What is protein synthesis?

The Flow of Information from Stored to Active Form

The cell can be viewed as a unit that assembles resources from the environment into biochemically functional molecules and organizes these molecules in three-dimensional space in a way that allows cellular growth and replication. In order to carry out this organizational process, a cell must have a biosynthetic means to assemble resources into useful molecules, and it must contain the information required to produce the biosynthetic and structural machinery. DNA serves as the stored form of this information, whereas protein is its active form. Although there are thousands of different proteins in cells, they either serve a structural role or are enzymes that catalyze the biosynthetic reactions of a cell. Following the discovery of the structure of DNA in 1953 by James Watson and Francis Crick, scientists began to study the process by which the information stored in this molecule is converted into protein.

Proteins are linear, functional molecules composed of a unique sequence of amino acids. Twenty different amino acids are used as the protein building blocks. Although the information for the amino acid sequence of each protein is present in DNA, protein is not synthesized directly from this source. Instead, RNA serves as the intermediate form from which proteins are synthesized. RNA plays three roles during protein synthesis. Messenger RNA (mRNA)
contains the information for the amino acid sequence of a protein. Transfer RNAs (tRNAs)
are small RNA molecules that serve as adapters that decipher the coded information present within an mRNA and bring the appropriate amino acid to the polypeptide as it is being synthesized. Ribosomal RNAs (rRNAs)
act as the engine that carries out most of the steps during protein synthesis. Together with a specific set of proteins, rRNAs form ribosomes that bind the mRNA, serve as the platform for tRNAs to decode an mRNA, and catalyze the formation of peptide bonds between amino acids. Each ribosome is composed of two subunits: a small (or 40s) and a large (or 60s) subunit, each of which has its own function. The “s” in 40s and 60s is an abbreviation for Svedberg units, which are a measure of how quickly a large molecule or complex molecular structure sediments (or sinks) to the bottom of a centrifuge tube while being centrifuged. The larger the number, the larger the molecule.

Like all RNA, mRNA is composed of just four types of nucleotides: adenine (A), guanine (G), cytosine (C), and uracil (U). Therefore, the information in an mRNA is contained in a linear sequence of nucleotides that is converted into a protein molecule composed of a linear sequence of amino acids. This process is referred to as “translation,” since it converts the “language” of nucleotides that make up an mRNA into the “language” of amino acids that make up a protein. This is achieved by a three-letter genetic code in which each amino acid in a protein is specified by a three-nucleotide sequence in the mRNA called a codon. The four possible “letters” means that there are sixty-four possible three-letter “words.” As there are only twenty amino acids used to make proteins, most amino acids are encoded by several different codons. For example, there are six different codons (UCU, UCC, UCA, UCG, AGU, and AGC) that specify the amino acid serine, whereas there is only one codon (AUG) that specifies the amino acid methionine. The mRNA, therefore, is simply a linear array of codons (that is, three-nucleotide “words” that are “read” by tRNAs together with ribosomes). The region within an mRNA containing this sequence of codons is called the coding region.

Before translation can occur in eukaryotic cells, mRNAs undergo processing steps at both ends to add features that will be necessary for translation. (These processing steps do not occur in prokaryotic cells.) Nucleotides are structured such that they have two ends, a 5′ and a 3′ end, that are available to form chemical bonds with other nucleotides. Each nucleotide present in an mRNA has a 5′ to 3′ orientation that gives a directionality to the mRNA so that the RNA begins with a 5′ end and finishes in a 3′ end. The ribosome reads the coding region of an mRNA in a 5′ to 3′ direction. Following the synthesis of an mRNA from its DNA template, one guanine is added to the 5′ end of the mRNA in an inverted orientation and is the only nucleotide in the entire mRNA present in a 3′ to 5′ orientation. It is referred to as the cap. A long stretch of adenosine is added to the 3′ end of the mRNA to make what is called the poly-A tail.

Typically, mRNAs have a stretch of nucleotide sequence that lies between the cap and the coding region. This is referred to as the leader sequence and is not translated. Therefore, a signal is necessary to indicate where the coding region initiates. The codon AUG usually serves as this initiation codon; however, other AUG codons may be present in the coding region. Any one of three possible codons (UGA, UAG, or UAA) can serve as stop codons that signal the ribosome to terminate translation. Several accessory proteins assist ribosomes in binding mRNA and help carry out the required steps during translation.

The Translation Process: Initiation

Translation occurs in three phases: initiation, elongation, and termination. The function of the 40s ribosomal subunit is to bind to an mRNA and locate the correct AUG as the initiation codon. It does this by binding close to the cap at the 5′ end of the mRNA and scanning the nucleotide sequence in its 5′ to 3′ direction in search of the initiation codon. Marilyn Kozak identified a certain nucleotide sequence surrounding the initiator AUG of eukaryotic mRNAs that indicates to the ribosome that this AUG is the initiation codon. She found that the presence of an A or G three nucleotides prior to the AUG and a G in the position immediately following the AUG were critical in identifying the correct AUG as the initiation codon. This is referred to as the “sequence context” of the initiation codon. Therefore, as the 40s ribosomal subunit scans the leader sequence of an mRNA in a 5′ to 3′ direction, it searches for the first AUG in this context and may bypass other AUGs not in this context.

Nahum Sonenberg demonstrated that the scanning process by the 40s subunit can be impeded by the presence of stem-loop structures present in the leader sequence. These form from base pairing between complementary nucleotides present in the leader sequence. Two nucleotides are said to be complementary when they join together by hydrogen bonds. For instance, the nucleotide (or base) A is complementary to U, and these two can form what is called a “base pair.” Likewise, the nucleotides C and G are complementary. Several accessory proteins, called eukaryotic initiation factors (eIFs), aid the binding and scanning of 40s subunits. The first of these, eIF4F, is composed of three subunits called eIF4E, eIF4A, and eIF4G. The protein eIF4E is the subunit responsible for recognizing and binding to the cap of the mRNA. The eIF4A subunit of eIF4F, together with another factor called eIF4B, functions to remove the presence of stem-loop structures in the leader sequence through the disruption of the base pairing between nucleotides in the stem loop. The protein eIF4G is the large subunit of eIF4F, and it serves to interact with several other proteins, one of which is eIF3. It is this latter initiation factor that the 40s subunit first associates with during its initial binding to an mRNA.

Through the combined action of eIF4G and eIF3, the 40s subunit is bound to the mRNA, and through the action of eIF4A and eIF4B, the mRNA is prepared for 40s subunit scanning. As the cellular concentration of eIF4E is very low, mRNAs must compete for this protein. Those that do not compete well for eIF4E will not be translated efficiently. This represents one means by which a cell can regulate protein synthesis. One class of mRNA that competes poorly for eIF4E encodes growth-factor proteins. Growth factors are required in small amounts to stimulate cellular growth. Sonenberg has shown that the overproduction of eIF4E in animal cells leads to a reduction in the competition for this protein, and mRNAs such as growth-factor mRNAs that were previously poorly translated when the concentration of eIF4E was low are now translated at a higher rate when eIF4E is abundant. This in turn results in the overproduction of growth factors, which leads to uncontrolled growth, a characteristic typical of cancer cells.

A protein that specifically binds to the poly-A tail at the 3′ end of an mRNA is called the poly-A-binding protein (PABP). Discovered in the 1970’s, the only function of this protein was thought to be to protect the mRNA from attack at its 3′ end by enzymes that degrade RNA. Daniel Gallie demonstrated another function for PABP by showing that the PABP-poly-A-tail complex was required for the function of the eIF4F-cap complex during translation initiation. The idea that a protein located at the 3′ end of an mRNA should participate in events occurring at the opposite end of an mRNA seemed strange initially. However, RNA is quite flexible and is rarely present in a straight, linear form in the cellular environment. Consequently, the poly-A tail can easily approach the cap at the 5′ end. Gallie showed that PABP interacts with eIF4G and eIF4B, two initiation factors that are closely associated with the cap, through
protein-to-protein contacts. The consequence of this interaction is that the 3′ end of an mRNA is held in close physical proximity to its cap. The interaction between these proteins stabilizes their binding to the mRNA, which in turn promotes protein synthesis. Therefore, mRNAs can be thought of as adopting a circular form during translation that looks similar to a snake biting its own tail. This idea is now widely accepted by scientists.

One additional factor, called eIF2, is needed to bring the first tRNA to the 40s subunit. Along with the initiator tRNA (which decodes the AUG codon specifying the amino acid methionine), eIF2 aids the 40s subunit in identifying the AUG initiation. Once the 40s subunit has located the initiation codon, the 60s ribosomal subunit joins the 40s subunit to form the intact 80s ribosome. (Svedberg units are not additive; therefore, a 40s and 60s unit joined together do not make a 100s unit.) This marks the end of the initiation phase of translation.

The Translation Process: Elongation and Termination

During the elongation phase, tRNAs bind to the 80s ribosome as it passes over the codons of the mRNA, and the amino acids attached to the tRNAs are transferred to the growing polypeptide. Binding of the tRNAs to the ribosome is assisted by an accessory protein called eukaryotic elongation factor 1 (eEF1). A codon is decoded by the appropriate tRNA through base pairing between the three nucleotides that make up the codon in the mRNA and three complementary nucleotides within a specific region (called the anticodon) within the tRNA. The tRNA binding sites in the 80s ribosome are located in the 60s subunit. The ribosome moves over the coding region one codon at a time, or in steps of three nucleotides, in a process referred to as “translocation.” When the ribosome moves to the next codon to be decoded, the tRNA containing the appropriate anticodon will bind tightly in the open site in the 60s subunit (the A site). The tRNA that bound to the
previous codon is present in a second site in the 60s subunit (the P site). Once a new tRNA has bound to the A site, the ribosomal RNA itself catalyzes the formation of a peptide bond between the growing polypeptide and the new amino acid. This results in the transfer of the polypeptide attached to the tRNA present in the P site to the amino acid on the tRNA present in the A site. A second elongation factor, eEF2, catalyzes the movement of the ribosome to the next codon to be decoded. This process is repeated one codon at a time until a stop codon is reached.

The termination phase of translation begins when the ribosome reaches one of the three termination or stop codons. These are also referred to as “nonsense” codons as the cell does not produce any tRNAs that can decode them. Accessory factors, called release factors, are also required to assist this stage of translation. They bind to the empty A site in which the stop codon is present, and this triggers the cleavage of the bond between the completed protein from the last tRNA in the P site, thereby releasing the protein. The ribosome then dissociates into its 40s and 60s subunits, the latter of which diffuse away from the mRNA. The close physical proximity of the cap and poly-A tail of an mRNA maintained by the interaction between PABP and the initiation factors (eIF4G and eIF4B) is thought to assist the recycling of the 40s subunit back to the 5′ end of the mRNA to participate in a subsequent round of translation.

Impact and Applications

The elucidation of the process and control of protein synthesis provides a ready means by which scientists can manipulate these processes in cells. In addition to infectious diseases, insufficient dietary protein represents one of the greatest challenges to world health. The majority of people now living are limited to obtaining their dietary protein solely through the consumption of plant matter. Knowledge of the process of protein synthesis may allow molecular biologists to increase the amount of protein in important crop species. Moreover, most plants contain an imbalance in the amino acids needed in the human diet that can lead to disease. For example, protein from corn is poor in the amino acid lysine, whereas the protein from soybeans is poor in methionine and cysteine. Molecular biologists may be able to correct this imbalance by changing the codons present in plant genes, thus improving this source of protein for those people who rely on it for life.

Key terms




amino acid


:

the basic subunit of a protein; there are twenty commonly occurring amino acids, any of which may join together by chemical bonds to form a complex protein molecule





peptide bond


:

the chemical bond between amino acids in protein




polypeptide

:

a linear molecule composed of amino acids joined together by peptide bonds; all proteins are functional polypeptides





RNA


:

ribonucleic acid, that molecule that acts as the messenger between genes in DNA and their protein product, directing the assembly of proteins; as an integral part of ribosomes, RNA is also involved in protein synthesis




translation

:

the process of forming proteins according to instructions contained in an RNA molecule





Bibliography

Atkins, John F., Raymond F. Gesteland, and Thomas Cech. RNA Worlds: From Life's Origins to Diversity in Gene Regulation. Cold Spring Harbor: Cold Spring Harbor Laboratory, 2011. Print.

Crick, Francis. “The Genetic Code III.” Scientific American 215 (1966): 57. Print.

Keiler, Kenneth C. Bacterial Regulatory RNA: Methods and Protocols. New York: Humana, 2012. Print.

Lake, James. “The Ribosome.” Scientific American 245 (1981): 84–97. Print.

Lewin, Benjamin, et al. Genes X. Sudbury: Jones, 2011. Print.

Liljas, Anders, and Måns Ehrenberg. Structural Aspects of Protein Synthesis. 2nd ed. Hackensack: World Scientific, 2013. Print.

Li Puma, Vito, and Carlo Bethaz. New Research on Protein Synthesis. New York: Nova Science, 2014. eBook Collection (EBSCOhost). Web. 26 Aug. 2014.

Rich, Alexander, and Sung Hou Kim. “The Three-Dimensional Structure of Transfer RNA.” Scientific American 238 (1978): 52–62. Print.

Tropp, Burton E., and David Freifelder. Molecular Biology: Genes to Proteins. 4th ed. Sudbury: Jones, 2012. Print.

Whitford, David. “Protein Synthesis, Processing, and Turnover.” Proteins: Structure and Function. Hoboken: Wiley, 2005. Print.

In To Kill a Mockingbird by Harper Lee, what kind of student is Scout?

There are several scenes throughout the novel that depict Scout inside of the classroom. Scout is more advanced than the rest of her pupils and continually volunteers to answer difficult questions. From this perspective, Scout is portrayed as a good student who is more than willing to participate in class. Her pupils also look up to her and encourage Scout to explain Walter Cunningham's background. Scout accepts the challenge and graciously tries her best to defend Walter. Although she fails to appropriately explain Walter's unique behavior, Scout is socially accepted by her peers and is viewed as a leader.

However, Scout finds school and the numerous mundane activities to be extremely boring. In her first grade class, she decides to write her friend Dill a letter in the middle of an activity. Scout ends up getting into trouble because writing is a skill that they are supposed to learn in third grade. Scout struggles to appreciate school because she is not challenged or encouraged to develop her already advanced skills. Scout's teachers may find her to be inattentive the majority of the time because Scout is simply uninterested in the material and slow pace of the class. Scout is the prototypical advanced student who is stuck in a class surrounded by slow learners. Unless the teacher is discussing something interesting, Scout tries her best to entertain herself, which can result in a less than a favorable reputation among her teachers.

What is the balanced equation when you oxidize propan-1-ol with potassium permanganate?

Propan-1-ol is also known as 1-propanol and is a primary alcohol. Potassium permangante is an oxidizing agent and oxidizes the primary alcohol to carboxylic acid in a two step process. In the first step, the primary alcohol is oxidized to an aldehyde and in the next step, the aldehyde converts to the carboxylic acid. The overall reaction is written as:

`C_3H_7OH + KMnO_4 -> C_2H_5COOH + MnO_2 + KOH + H_2O`

In this equation, the primary alcohol gets oxidized, while the permanganate gets reduced. However, this equation is not balanced. One can check that by counting of number of atoms of each species on the reactant side and product side of the chemical equation. For example, number of hydrogen atoms on reactant side is 8, while on the product side, it is 9. 

The well-balanced chemical equation is as follows:

`3C_3H_7OH + 4KMnO_4 -> 3C_2H_5COOH + 4MnO_2 + 4KOH + H_2O`

Interestingly, this reaction works only for the primary alcohol. 

With a secondary alcohol, acetone is the final product. With a tertiary alcohol, no oxidation takes place.

Hope this helps. 

What is the relationship between the ideas of John Locke and those contained in the U.S. Declaration of Independence?

The relationship between the ideas of John Locke and those contained in the Declaration of Independence is that the main ideas in the second section of the Declaration come from Locke.  The people who wrote the Declaration had read Locke’s writings and Locke had influenced them greatly.  They borrowed almost directly from him in writing that part of the Declaration.

The first relevant part of the Declaration comes when the document says that

all men … are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

This comes fairly directly from Locke.  Locke says, in his Second Treatise on Government, that the “law of nature” says that “no one ought to harm another in his life, health, liberty, or possessions.”  Locke then goes on to say that the reason why no one should do this is because all people were made by an “omnipotent, and infinitely wise maker” and that people had no right to take away what the maker had given.  We can see that Locke’s ideas and those of the Declaration are very similar here.  The only real difference is that the Declaration substitutes the phrase “pursuit of happiness” for “possessions.”

The second relevant part of the Declaration says that governments get “their just power from the consent of the governed.”  This, too, comes from Locke.  Locke says that no man can be “subjected to the political power of another, without his own consent.”  Once again, these ideas are practically identical.

Third, the Declaration says that the people have the right to change or to overthrow their government if it fails to protect their rights.  Locke says something very similar.  He says that, whenever the government tries

to take away, and destroy the property of the people, or to reduce them to slavery under arbitrary power

then the people no longer have to obey the government.  Instead, the people have the right to throw off the government and create a new one.

From all of this, we can see that the second section of the Declaration of Independence comes almost directly from the ideas of John Locke as set out in his Second Treatise.  This is the relationship between Locke’s ideas and those of the Declaration.

What were the grievances of the peasants before the French Revolution?

Although many factors led up to the French Revolution, the peasants—part of the citizenry making up the Third Estate—significantly influenced the government's overthrow.

The peasants' largest grievance in the run-up to the French Revolution was the burden of taxation from all corners of government. Peasants were taxed by the church, their landlords, and the crown. Combined with the burden of taxation, crops were failing, leaving peasants to fend for themselves. Fearing a coordinated uprising, the French government abolished the feudal system in 1793.

Another grievance, also tied to financial concerns, was the lack of religious freedom in the feudal system. Landowners were Catholic, and therefore those on their land were forced to tithe 10% to the Catholic Church, whether they wanted to or not. The Protestant Reformation had begun over two centuries prior, but France was still a deeply Catholic nation. Like other European citizens, peasants wanted to subscribe to the faith of their choosing. 

Finally, peasants wanted more equitable representation in government. Often, each of the Three Estates received one vote on policy decisions. Despite how much smaller they were than the peasants in the Third Estate, the clergy and nobility were each their own Estate. The clergy and nobility often voted similarly, canceling out the voice of the people. The peasants wanted more of a say in their own destinies.

If 1144 grams of silver chloride were allowed to decompose, how many liters of chlorine gas would be produced? (assume STP conditions)

Silver chloride (AgCl) decomposes according to the following reaction:

    `~2AgCl -gt 2Ag + ~Cl_2` ` `

Identify Information in the Problem:

This is a stoichiometry problem. The given amount is 1144 g AgCl. The final substance is L of `~Cl_2`.

Preliminary Calculation: Calculate the molar mass of AgCl.

Notice that the unit of the given substance (AgCl) is grams. Whenever the unit "grams" is used with a substance in a stoichometry problem, you will need to calculate the molar mass of the substance before you start working the problem. The molar mass of a compound is equal to the sum of the atomic masses of each element in the compound. The atomic mass of each element can be found in the periodic table.

   Atomic mass Ag = 107.868 g

   Atomic mass Cl = 35.453 g

   molar mass AgCl = 107.868 g + 35.453 g = 143.321 g

Stoichiometry Calculations:

Step 1: Convert the given substance to moles by multiplying by the conversion factor "1 mol = molar mass". Earlier, we determined that the molar mass of AgCl = 143.321 g. So, the conversion factor becomes, 1 mol AgCl = 143.321 g AgCl.

   1144 g AgCl x (1 mol AgCl/143.321 g AgCl) = 7.982 mol AgCl

Notice that the conversion factor "1 mol = 143.321 g" is oriented such that the "gram" part of the conversion factor is in the denominator. This enables us to cancel out grams and be left in moles. 

Step 2: Refer back to the balanced equation for the decomposition of AgCl. Notice that the coefficient of the given substance AgCl is 2, and the coefficient for the final substance `~Cl_2` is 1. Create a conversion factor using the coefficients of the given and final substances: 2 mol AgCl = 1 mol `~Cl_2` .

Multiply the moles of AgCl (from Step 1) by the coefficient conversion factor.

   7.982 mol AgCl x (1 mol `~Cl_2` /2 mol AgCl) = 3.991 mol `~Cl_2`

Notice that the coefficient conversion factor is oriented such that the "mol AgCl" part of the conversion factor is in the denominator. This enables us to cancel out "mol AgCl" and be left with "mol `~Cl_2` ".

Step 3: Convert moles of `~Cl_2` (from Step 2) to liters by multiplying by the conversion factor "1 mol = 22.4 L".

   3.991 mol `~Cl_2` x (22.4 L `~Cl_2` /1 mol `~Cl_2` ) = 89.40 L `~Cl_2`

Notice that the conversion factor "1 mol = 22.4 L" is oriented such that the "mole" part of the conversion factor is in the denominator. This enables us to cancel out moles and be left in liters. 

What did Eliza, Pickering and Higgins each do for a living in Pygmalion?

Eliza sells flowers on the streets of east London, Pickering is a linguist and retired soldier, and Higgins is a linguistic scientist and professor of phonetics. But this doesn't really tell us all that we need to know in a play that is an exploration and critique of the British class system. Higgins and Pickering are vastly wealthier than Eliza, who has never been seen a bathtub and rents a unheated room, barely scraping by on her income of about half a crown a day. To the men, half a crown is pocket change, nothing--to her it is her all in all. This comes out early in the play, when Eliza arrives at Higgins' home prepared to pay a shilling for speech lessons. 

As Higgins says to Pickering:

You know, Pickering, if you consider a shilling, not as a simple shilling, but as a percentage of this girl's income, it works out as fully equivalent to sixty or seventy guineas from a millionaire.

This shilling, laughable to Higgins and Pickering, is, in other words, a large percentage of Eliza's income. 

Higgins thinks the difference in their income means he can treat Eliza despicably, but the play shows there's more to class than the accident of birth. 

How does the Odyssey demonstrate that although life can be difficult, the end result is worth the struggle?

You have rightly recognized that the Odyssey can be viewed as metaphor for the journey of life. Odysseus faced a daunting (and very dangerous), ten-year journey home to his wife, Penelope, and son, Telemachus.

At several points in the story, he was given the option to give up or compromise his quest. For instance, the beautiful goddess Calypso wanted Odysseus to marry her and start a new family with her on her island. However, Odysseus refused to trade his goal for what would only be a shadow of the real thing.

At another juncture, Odysseus was sidetracked from his quest by a year-long affair with Circe, another goddess. However, Odysseus eventually remembered his quest and made the decision to get back on track.

Like Odysseus, most people encounter difficult experiences on the journey of life. They may be tempted to abandon their goals, or at least compromise them for lesser ones. However, like Odysseus--who eventually returned home to his wife and son--one will find that life is worth the struggle.

What is mitral valve prolapse?

Causes and Symptoms

The mitral valve connects the heart’s left ventricle and left atrium. The oxygenated blood, having already passed through the right heart chambers and the lungs, arrives in the left atrium through the pulmonary
veins and then passes through the mitral valve into the left ventricle. Compression of the left ventricle pumps the blood into the aorta and on to the rest of the body. A properly functioning mitral valve closes and prevents regurgitation or backflow into the left atrium. Mitral valve prolapse occurs when the two leaves of the mitral valve close imperfectly, allowing leakage. This condition, known also as mitral valve insufficiency prolapse, is the most common cardiac syndrome. Found in all segments of society, it is most common in young adult women.

Mitral valve prolapse has several possible causes including rheumatic fever, inflammation of the heart lining (endocarditis), cardiac tumors, or most often, genetic error. Its symptoms are undue fatigue after exercise, shortness of breath, and chest pain. Other common complaints are anxiety, depression, and panic, all related to stress. The number of diagnosed cases in Western countries is rising markedly and may be the result of more sophisticated diagnostic techniques or the increasing stress in modern society.

Perspective and Prospects

Until the 1960s, the detection of mitral valve prolapse was through a characteristic “click” heard by the physician when the mitral leaves attempted to close. Now the use of echocardiograms, allowing ultrasound images of the beating heart and blood flow, is standard practice.

People with mitral valve prolapse lead a normal life, and many are unaware that they have the condition. Repeated irregularity in breathing or an inexplicable shortness of breath is a sign to see one’s physician. Regular exercise and good eating habits are recommended for this mild condition. Only in severe cases is mitral valve prolapse treated surgically or considered life-threatening.

Bibliography

Alpert, Joseph S., James E. Dalen, and Shahbudin H. Rahimtoola, eds. Valvular Heart Disease. 3d ed. Philadelphia: Lippincott Williams & Wilkins, 2000.

Badash, Michelle. "Mitral Valve Prolapse." Health Library, May 9, 2013.

Boudoulas, Harisios, and Charles F. Wooley, eds. Mitral Valve: Floppy Mitral Valve, Mitral Valve Prolapse, Mitral Valvular Regurgitation. 2d ed. Armonk, N.Y.: Futura, 2000.

Crawford, Michael, ed. Current Diagnosis and Treatment—Cardiology. 3rd ed. New York: McGraw-Hill Medical, 2009.

Eagle, Kim A., and Ragavendra R. Baliga, eds. Practical Cardiology: Evaluation and Treatment of Common Cardiovascular Disorders. 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2009.

Frederickson, Lyn. Confronting Mitral Valve Prolapse Syndrome. New York: Warner Books, 1992.

Gersh, Bernard J., ed. The Mayo Clinic Heart Book. 2d ed. New York: William Morrow, 2000.

"Mitral Valve Prolapse." Mayo Clinic, April 21, 2011.

"What Is Mitral Valve Prolapse?" National Heart, Lung, and Blood Institute, July 1, 2011.

What is the relationship between breast milk and infectious disease?

Definition

The female breast is a “factory” of milk production. It is composed of
milk-producing mammary glands
and lactiferous ducts that carry milk to the nipple, which is
surrounded by fatty tissue. Breast milk provides ideal nutrition for a growing newborn and offers significant advantages for the baby’s immune system. It has been known for some time that breast-fed infants contract
fewer infections than those who are formula-fed, but only lately have experts come
to understand and identify the specific immune components that are transferred to
the infant in breast milk.

Breast milk also contains microorganisms, a few of which can be passed to the infant, leading to infection and clinical disease. Rarely, the considerable benefits of breast-feeding must be weighed against the risk of transmitting infection.

Breast-feeding can also be a source of infection in the
breast. Mastitis (infection of the breast tissue) is commonly seen
between one and three months of delivery and may cause pain, fever, and malaise in
the mother, which makes care of the newborn difficult. In almost all cases, it is
recommended that a woman with mastitis continue to breast-feed.

Immunity

During the first months of life, the infant’s immune system is immature and
unable to make the proteins and cells necessary to respond to “foreign” invaders.
Breast milk helps to offer protection in a number of ways. During pregnancy
immunoglobulins cross the placenta to help protect the fetus from infections. Some
types of antibodies can cross the placenta. IgM, the first antibody
to fight acute infection, does not cross the placenta.

All five major antibody types—IgG, IgA, IgM, IgD, and IgE—have been found in human breast milk and are active when ingested by the nursing infant. The most abundant is the type known as secretory IgA, which binds with potential pathogens, preventing them from invading the infant’s system. All antibody types are specific for only one pathogen and do not attack irrelevant or commensal (good) organisms. Other important immune molecules are present in breast milk too. Oligosaccharides (chains of sugars) and mucins (large molecules made of protein and carbohydrates) are able to clump together with invading bacteria, making them harmless.

White blood
cells (leukocytes) are abundant in breast milk; most notably in colostrum, the milky fluid that precedes the flow of milk. Neutrophils, macrophages, and lymphocytes are all present and play a role in protecting the infant from
disease. In addition, studies suggest that some hormones and other factors in
breast milk may induce the infant’s own immune system to mature more rapidly,
allowing breast-fed infants to protect themselves sooner than formula-fed
infants.

Infection Transmission

Few organisms are passed readily by breast milk to cause clinical infection, and it may be difficult to accurately determine the mode of transmission, because breast-feeding requires close contact between mother and infant. Some infections that are spread during the breast-feeding period pass by other means, such as airborne droplets or skin contact. Concern about infection rarely leads to a recommendation against breast-feeding.

Three viruses can be transmitted through breast milk and are of greatest
clinical concern. These include cytomegalovirus (CMV), human immunodeficiency virus
(HIV), which causes acquired immunodeficiency syndrome or
AIDS, and humanT-lymphotrophic virus (HTLV). It is thought that transmission
occurs through exposure to small amounts of virus for several feedings each day
during the prolonged period of breast-feeding.

CMV is a common cause of congenital infection. Most women are infected before becoming pregnant and develop antibodies that cross the placenta to protect the growing fetus and breast-feeding infant. However, if the woman experiences primary infection during pregnancy or breast-feeding, inadequate immune resources and infection can result.

Breast-feeding by an HIV-positive mother increases transmission risk up to 25 percent, in addition to the risk of perinatal transmission. There is no adequate immune protection for mother or infant. HIV-positive mothers should avoid breast-feeding to prevent mother-to-child transmission
.

HTLV is a cause of adult leukemia and other chronic conditions, and it is endemic to several regions of the world. Transmission occurs more often in breast-fed than in formula-fed infants. Mother-to-child transmission can be avoided by not breast-feeding.

Bacterial and other infections are rarely passed to infants through breast
milk. Some infections, including having gonorrhea, group B strep, syphilis, or
tuberculosis, could lead to an interruption of breast-feeding for a brief time,
while the mother or the mother and infant begin antimicrobial therapy. One should
not necessarily stop breast-feeding if using antibiotics.

Infection in the Lactating Breast

Mastitis can occur when bacteria from the infant’s mouth or the mother’s skin enter a duct through a sore, cracked nipple and multiply in breast milk, which is an ideal growth medium. This condition may lead to a localized, minor infection or a more serious deep-breast abscess. Symptoms include tenderness and swelling of the breast, fever, chills, and other flulike symptoms.

Breast infections require treatment with antibiotics. Prevention includes good hygiene and handwashing and proper breast-feeding technique to avoid cracked nipples. Most women with mastitis should continue to breast-feed; doing so does not harm the infant. Also, emptying the breast through feeding speeds healing.

Impact

Breast-feeding provides important protection against disease. The immunologic benefits are well documented and beyond question. For those few circumstances where disease transmission is of concern, more work is needed to develop vaccines and other interventions.

Bibliography

Barbosa-Cesnik, C., K. Schwartz, and B. Foxman. “Lactation Mastitis.” Journal of the American Medical Association 289 (2003): 1609-1612.

Huggins, Kathleen. The Nursing Mother’s Companion. 5th ed. Boston: Harvard Common Press, 2005.

Jackson, Kelly M., and Andrea M. Nazar. “Breastfeeding, the Immune Response, and Long-Term Health.” Journal of the American Osteopathic Association 106, no. 4 (2006): 203-207.

Lawrence, Robert, and Ruth Lawrence, eds. Breastfeeding: A Guide for the Medical Profession. St. Louis, Mo.: Mosby, 1999.

Mestecky, Jim, et al., eds. Immunology of Milk and the Neonate. New York: Plenum Press 1991.

Riordan, Jan, ed. Breastfeeding and Human Lactation. 4th ed. Sudbury, Mass.: Jones and Bartlett, 2010.

In "The Secret Life of Bees," what made some of the honey purple?

In Sue Monk Kidd's "The Secret Life of Bees," the reader learns the cause of purple honey during an exchange between Lilly and Zach. As Lilly is learning the ins and outs of beekeeping, Zach shows her a beehive which drips with an unusually colored honey: "The frame leaked with honey the color of plums," Kidd writes. In the passage, Zach goes on to explain to Lilly: "When the weather turns dry and the flowers dry up, the bees start sucking elderberry. It makes a purple honey.  People will pay two dollars a jar for purple honey."

This passage, though brief, informs us of two significant factors that go into the making of purple honey.  First, the bees must drink the nectar of a purple-colored plant (elderberry). And secondly, Zach's words imply that this only happens when the bees are somewhat desperate, due to drought conditions and the local flowers drying up.  

Although there is only a brief reference to purple honey in the novel, it appeals to the reader's imagination because it is an unusual color we do not generally associate with honey.  It is an intriguing detail Kidd supplies us with, which is easy for the reader to visualize. Lilly's character echoes the excitement we feel when she exclaim's, "Purple honey!" in amazement.

What is gonorrhea?

Causes and Symptoms

Gonorrhea is the second most common bacterial sexually transmitted infection (STI) in the United States, the most common being chlamydia. In the United States, the incidence of gonorrhea has fallen. In 1995, the incidence was about 150 cases out of every 100,000 persons, down from the mid-1970’s of more than 400 cases per 100,000 persons. After 1997, the percentage of infections increased slightly, but by 2009, the rate per 100,000 reached an all-time low of 98.1. The following two years saw a slight increase in the rate of infection, reaching 104.2 in 2011. However, overall, from 2007 to 2011, the rate of infection decreased by nearly 12 percent. The highest incidence of gonorrhea is in sexually active men and women under twenty-five years of age; since 2002, the rate of infection for women of any age group has been higher than for men (108.9 cases per 100,000 compared with 98.7 for men).

Gonorrhea is caused by the bacterium Neisseria gonorrhea, a gram-negative diplococcus. The bacterium infects the mucous membranes with which it comes in contact, most commonly the urethra and the cervix but also the throat, rectum, and eyes. Some men will be asymptomatic, but most will experience urinary discomfort and a purulent urethral discharge. Long-term complications of this infection in men include epididymitis, prostatitis, and urethral strictures (scarring). In women, the disease is more likely to be asymptomatic.

Women with symptoms may have purulent vaginal discharge, urinary discomfort, urethral discharge, lower abdominal discomfort, or pain with intercourse. Pelvic inflammatory disease (PID)
and its consequences may occur if gonorrheal infection ascends past the cervix into the upper genital tract (uterus, Fallopian tubes, ovaries, and pelvic cavity) in women. Complications of PID include infertility and an increased risk of ectopic pregnancy.

In rare cases, gonorrhea can enter the bloodstream and disseminate throughout the body, causing fever, joint pain, and skin
lesions. Gonorrhea can infect the heart valves, pericardium, and meninges as well. When it infects the joints, a condition known as septic arthritis

occurs, characterized by pain and swelling of the joints and potential destruction of the joints.

Gonorrhea can be transmitted to infants through the birth canal, leading to an eye infection that can damage the eye and impair vision. Fortunately, erythromycin eye drops are routinely given to newborns to prevent eye infection. These eyedrops are effective against Neisseria gonorrhea as well as Chlamydia trachomatis.

Treatment and Therapy

Treatment for gonorrhea consists of the use of antibiotics. With the development of penicillin-resistant strains of gonorrhea, effective therapy relies on antibiotics, such as ceftriaxone, to which gonorrhea remains susceptible. In uncomplicated cases of gonorrheal infection, such as cervicitis or urethritis, a single dose is given.

A patient who has risk factors for STIs (primarily contact with a suspected infected partner) or a clinical picture suggestive of gonorrhea, or both, may receive treatment presumptively, before confirmatory laboratory test results for gonorrhea are available. Because a large number of patients with gonorrhea also have chlamydia, patients are treated concomitantly with an antibiotic directed against chlamydia, such as azithromycin. Occasional doxycycline may be used as well. Once laboratory test results confirm the diagnosis of gonorrhea, patients should be advised that it is recommended that they be tested for other STIs, such as Human immunodeficiency virus (HIV), hepatitis B and C, and syphilis.

As with all STIs, a key component of therapy includes counseling regarding safer sex. This includes the use of barrier contraceptives, such as condoms, and the avoidance of high-risk sexual behaviors. Contact tracing is another important element to STI treatment. It notifies the patient’s sexual partners of their exposure to gonorrhea or other STIs. Contact tracing also involves offering resources to these partners for medical attention. Contact tracing can prevent both reinfection of the patient through subsequent sexual encounters and can prevent the spread of STIs from the patient’s partner to his or her subsequent sexual partners.

Perspective and Prospects

The symptoms of gonorrhea have been described in numerous cultures in the past, including those dating back to the ancient Chinese, Egyptians, and Romans. The actual gonorrhea bacterium was first identified by Albert Neisser in the 1870s, and it was one of the first bacteria ever discovered. Neisseria gonorrhea has continued to be well-studied on both the molecular and the epidemiological level.

Antibiotic therapy, in the form of sulfanilamide, was first used to combat N. gonorrhea in the 1930s. By the 1940s, however, gonococcal strains resistant to this antibiotic appeared, and the therapy of choice became penicillin. Over the next several decades, N. gonorrhea evolved the ability to resist penicillin, forcing clinicians to use other drugs to combat the bacterium, such as ceftriaxone and ciprofloxacin. In the 1980s, the Centers for Disease Control instituted surveillance programs to monitor antibiotic resistance
patterns in different US cities. Continued success in combating N. gonorrhea will depend on the ability to minimize the development of antibiotic resistance.

Finally, since many patients with gonorrhea infection have no symptoms, screening programs of asymptomatic patients who are in high-risk groups (those younger than twenty-five and/or with multiple sexual partners) play a vital role in decreasing the incidence of N. gonorrhea infections.

Bibliography

Armed Forces Health Surveillance Center. "Predictive Value of Reportable Medical Events for Neisseria gonorrhoeae and Chlamydia trachomatis. MSMR 20, no. 2 (February, 2013): 11–14.

Beharry, M. S., T. Shafii, G. R. Burstein. "Agnosis and Treatment of Chlamydia, Gonorrhea, and Trichomonas in Adolescents." Pediatric Annals 42, no. 2 (February, 2013): 26–33.

Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines 2010. Atlanta: Author, 2010.

Shmaefsky Brian R. Gonorrhea. 2d ed. New York: Chelsea House, 2011.

Holmes, King K., et al., eds. Sexually Transmitted Diseases. 4th ed. New York: McGraw-Hill Medical, 2008.

Kasper, Dennis L., et al., eds. Harrison’s Principles of Internal Medicine. 18th ed. New York: McGraw-Hill, 2012.

Ryan, Kenneth J., and C. George Ray, eds. Sherris Medical Microbiology: An Introduction to Infectious Diseases. 4th ed. New York: McGraw-Hill, 2004.

Sutton, Amy L., ed. Sexually Transmitted Diseases Sourcebook. 5th ed. Detroit, Mich.: Omnigraphics, 2013.

How can I compare and contrast Ernest Hemingway's "Soldier's Home" to its film adaption directed by Robert Young?

Robert Young's film adaptation of Hemingway's short story "Soldier's Home" portrays its essence without duplicating it exactly. The setting is a small Oklahoma town and Young depicts the time and the setting adequately. The tone of the film is somber and detached just as Hemingway's writing is. While emotions are expressed, Krebs seems fittingly oblivious. Hemingway's statement in the story that Krebs simply wanted to live an uncomplicated life is illustrated by the actor's ability to remain almost deadpan throughout the film.

Only once, in a scene not in the story, does he divert from this emotionless state. At a dance he tries to make out with a girl who, while teasing him, doesn't want to go that far. The scene, however, is implied in the story when Krebs admits he would like to be with a girl but doesn't want to engage in the level of social conventions it would take. By immediately kissing the girl he displays his character's impatience with social norms.

Other than the aforementioned scene, the plot of the film follows Hemingway's story quite well. It even includes the photographs described in the opening lines of the story. The first scene of the film shows a smiling Krebs posing for a picture with his college fraternity. When Krebs returns from the war, he rarely smiles. He is also carrying the photograph taken with two German girls, which seems to be his only memento from the war.

Krebs checks out books about the war just as in the story. He is interested in sorting out the details of what he went through. When queried about the war he is mostly silent. The film never portrays the lies about the war which Hemingway includes in the story. Instead, the film adds another character, Kenner, who is a wounded veteran who seems outwardly as lost as Krebs. He is almost like Krebs's alter ego. He drinks and carouses to forget. The two go to a dance which is not part of the story and end up disagreeing about their feelings for the war. It is emblematic of Krebs's desire to live an uncomplicated life. Kenner's life is anything but uncomplicated as he seems to be dealing with the war in a negative way.

Finally, Young depicts the final scene with Krebs and his mother almost exactly. In this scene Krebs reveals that he neither loves his mother nor will he pray with her. The actor's performance replicates Krebs's feelings in this scene. Hemingway writes just after Krebs tells his mother he doesn't love her,

It wasn't any good. He couldn't tell her, he couldn't make her see it. It was silly to have said it. He had only hurt her. He went over and took her by the arm. She was crying with her head in her hands.

The mother is right from the book. She displays both optimism and religious devotion. She doesn't understand Harold. His father too is similar. Unlike in the story, he actually appears in a short scene. He is typically American with impatience regarding anything but business concerns. For some reason the sister's name is changed from Helen to Margaret and the scene where she says Harold is her "beau" is totally left out. Overall, the characterizations seem loyal to the written word, especially those of Harold and the mother, who are the main characters. The added characters, Kenner and Roselle Simmons, are important because they help visually reveal Harold's feelings.

Describe Augustus's rise to power.

Augustus rose to power by defeating Mark Antony. 

Augustus was the heir to Julius Caesar, but he became Rome’s first emperor through guts and intelligence.  He knew how to surround himself with people who could accomplish his goals and quietly get rid of detractors.  He was ambitious, ruthless, and pragmatic. 

Augustus was born Gaius Octavius.  When Julius Caesar was assassinated he left Octavius as his heir.  He did not choose Octavius at random.  He had no son, and was obviously aware that of all of his relatives, young Octavius had the best chance to take over his rise to power.  Caesar may not have expected to be assassinated in 44 B.C., but he already knew then that the teenage Octavius was something special.

Octavius did have some military training when Julius Caesar died, but it was really just beginning.  He was too young to command an army, and he suffered from a few physical infirmities that made military life difficult.  This did not stop him.  He was cunning and observant.  He turned every situation to his advantage.  He was only eighteen years old when Caesar died, but within a few years he would be one of the three leaders of the Roman world.

Mark Antony was Octavius’s ticket to power.  He called himself Octavius Caesar, using his “father’s” name to add clout to his status.  The senate gave him an army and asked him to help put down Mark Antony’s, but instead he joined him.  Antony, Octavius Caesar, and Lepidus formed a triumvirate (a power-sharing arrangement) a year later.

Although Antony likely considered himself the leader of this band over a teenager and a nobody, Octavius was already gaining supporters.  He wanted people to think that he was Caesar’s heir in every way.  When the war ended at the final defeat of Brutus and Cassius, Octavius did not go into the woodwork. 

Antony and Octavius had more and more disputes in intervening years over sharing power.  By now Octavius Caesar had a trusted lieutenant, Agrippa, who was a brilliant military strategist.  He also had other advisers in just about every area, including a crucial area Antony lacked: publicity.

Antony’s greatest publicity problem was Cleopatra.  She was the queen of Egypt and many Romans considered her Antony’s weakness.  Octavius used her and several military failures of Antony to make him look weak and ineffectual.  He also took advantage of an attempted coup by Lepidus to force out their third triumvir.  Soon Antony was the only obstacle left to his power.

History has made Antony and Cleopatra into a love story for the ages.  To Rome, Antony’s relationship with her was scandalous.  Antony supposedly recognized her and his children with her in his will, even giving her Roman territory.  Octavius got the will and read it to the senate, embarrassing Antony.  He also read his own will by contrast, which was glowing with love for Rome.

As was bound to happen, Antony made a move against Octavius.  It was doomed.  Antony had too few men and resources left, and Octavius had both.  He also had Agrippa.  With his help, Octavius defeated Antony soundly, and both Antony and Cleopatra committed suicide.  Octavius had Cleopatra’s oldest son Caesarian (Julius Caesar’s son) killed, and had Antony and Cleopatra’s children marched through Rome in triumph. 

Now Octavius Caesar had all of Rome under his thumb.  There were no more power-sharing arrangements with Antony to honor.  He changed his name to Augustus and declared himself emperor.  He also completed an ambitious program of public works for Rome, from libraries to sewers.

Explain why burning magnesium continues to burn, but burning sulfur is extinguished when dropped in gas containing NO.

Both magnesium and sulfur need oxygen for burning to occur and continue. The amount of oxygen available is what determines whether the burning will continue or be extinguished. Dropping burning magnesium or sulfur into a jar causes oxygen to become a limiting factor in the combustion reactions.

When magnesium is burning, it produces more heat energy than sulfur. As a result, the heat produced by the burning magnesium causes the NO to break down into N2 and O2. The O2 allows the combustion, or burning, of the magnesium to continue. The magnesium will continue to burn as long as there is sufficient O2 for the combustion reaction to continue.

When burning sulfur is dropped into the jar containing NO, the heat it produces is not enough to cause the breakdown of NO to N2 and O2. As a result, there is insufficient O2 in the jar to allow the combustion of the sulfur to continue, and so the burning sulfur is extinguished.

What is the relevance of A Mercy for a student today?

Morrison's A Mercy can teach modern students that America is comprised of "outsiders."

American students currently experience a great deal of social and political chatter about being "American." Presidential candidates talk about making America "great" again. Given the global threat of terrorism, many leaders have no problem saying that there are those who are "like us" and those who are "different."  Morrison's work is relevant because it shows that Americans are essentially orphans.  People who settled America into what it is today came from other nations.  Their backgrounds are not the simplistic notion of "America" that modern students hear of in today's political and social settings.

The characters in A Mercy show the divergent definition in America's past.  Florens is the product of rape, while Vaark has experienced the very worst in human treatment.  Rebekka is transplanted from England, and represents the essence of a stranger in a strange land. Lina is a slave who has seen everyone near her die of disease, while Sorrow is a "mongrel." Each of them must work to make a life in America.  They represent how there is no such thing as a pure "American."  The country is formed by people who are hybrids from other countries and settings.  They apply their past experience to the New World.  

Modern students could find this discussion quite meaningful.  It allows them to parse through the discourse that suggests that being "American" is simple and easy to understand.  Morrison instructs readers that to be an American means to embrace a very complex past.  Nuance replaces simplicity. a lesson that could be quite relevant to modern students.

How are the concepts of species, population, and community related?

Species, population, and community are concepts commonly studied in ecology. They are sometimes called levels of organization in ecology. 

A species refers to individual organisms that can reproduce and produce fertile offspring. For example, horses belong to their own species. They can reproduce and their offspring can reproduce. Donkeys are their own species for the same reason. However, if a horse breeds with a donkey the offspring, a mule, is not fertile. Since the mule cannot produce offspring, it is a not a species. This also provides evidence that a horse and donkey are two separate species. The process of determining what constitutes a species can get very complicated, especially when working with plants. The example I've provided is part of the biological species concept and is a common way to define a species.

A population is a collection of all of the members of a specific species in a given area. For example, all of the walleye in a lake can be considered a population. A population will contain its own genetic variation, and there will also be genetic variation between different populations. If a population is isolated from other populations over long periods of time, they may become so genetically different that they become their own species. 

A community includes all of the populations of living organisms in a given area. For example, the collection of all living organisms in the lake with the walleye is a community. At the community level of ecology we begin to see many different interactions happen between different species. Common interactions include predator-prey interactions, competition, and symbiosis. At the community level we can also observe food webs and study how energy flows through an environment. Communities with higher levels of diversity are usually considered more stable and resilient to disturbances than communities with low levels of diversity.

In short, a individuals of a species are part of a population, and a population is part of a community. 

Was the colonization of the Americas a positive or a negative?

There are really three groups of people that need to weigh in on this question and they probably would all have different responses. Europeans, especially from the elite classes, would view the exploration of America as a positive. It opened new lands for colonization and the acquisition of material wealth. While that the Europeans sought was not readily available, Europeans benefited from establishing cash crops systems in the New World. The exploration of America also produced a number of agricultural goods like corn, potato, and tomato that were not available before the voyages of Columbus.

For their part, the Europeans brought the horse to America. They also brought deadly diseases that the Native Americans were not immune to. For this reason, if you ask the Native population, they would view exploration as a disaster. Their populations were practically wiped out by disease and warfare that occurred from defending their homeland. Native populations faced the loss of their ancestral lands for centuries that followed the voyage of Columbus. Africans would not have felt the exploration of the Americas was a positive either. Because of the demand for labor on the large cash crop plantations, Africans were targeted for slave labor in the New World. Millions were forced across the Atlantic Ocean and into slavery in the Americas.

What do you observe when iron sulfate is added to copper?

When iron sulfate is added to copper, no reaction will occur. We can predict whether a single replacement reaction will occur by looking at the metal activity series.

The metal activity series is a list of metals from the most reactive metal to the least reactive metal. In order for a single replacement reaction to occur, the individual metal element must be higher on the activity series than the metal in the compound that it is trying to replace.

Part of the metal activity series is shown below:

  Iron (Fe)

  Cobalt (Co)

  Nickel (Ni)

  Tin (Sn)

  Lead (Pb)

  Copper (Cu)

Let's look at the situation involving copper and iron sulfate:

   Cu + `~FeSO_4` ->

In order for this reaction to occur, Cu would need to be higher on the activity series than Fe. Instead, Fe is higher on the series than Cu. The reaction will not occur because Cu is not reactive enough to replace Fe in the compound.

The contrast of youth and old age is important in this play. How far do you agree with this statement?

Shakespeare definitely presents a generation gap in Romeo and Juliet. Both Romeo and Juliet believe the older characters, Friar Lawrence and the Nurse, do not understand their love for each other. Juliet makes reference to the idea in Act II, scene 5 during her soliloquy to open the scene. Romeo does the same thing after the fight in Act III. He accuses the Friar of not realizing the depth of his love for Juliet.

At the beginning of Act II, Romeo proposes marriage to Juliet. Later in the Act, Juliet sends the Nurse to discover Romeo's plans. In scene 5, Juliet is anxiously awaiting the Nurse's return. The Nurse is late and Juliet remarks that if the woman were younger she would be quicker and would better understand Juliet's feelings. Juliet says,

Had she affections and warm youthful blood,
She would be as swift in motion as a ball;
My words would bandy her to my sweet love,
And his to me.
But old folks, many feign as they were dead,
Unwieldy, slow, heavy, and pale as lead.

The Nurse is also slow in revealing Romeo's arrangements and it drives Juliet crazy. She cajoles the Nurse but it doesn't speed up the news. The Nurse doesn't understand Juliet's haste and comments,

O God’s lady dear,
Are you so hot? Marry, come up, I trow.
Is this the poultice for my aching bones?
Henceforward do your messages yourself.

A similar conversation takes place between Romeo and the Friar in Act III, scene 3. Romeo has just killed Tybalt and taken refuge in Lawrence's cell. When the Friar gives Romeo the news that he has been banished, Romeo launches into a whining rant. He laments the fact that he won't be able to see Juliet and that he'd rather be dead. When the Friar tries to reason with him, Romeo accuses the Friar of being old and not comprehending his feelings. Romeo says,

Thou canst not speak of that thou dost not feel.
Wert thou as young as I, Juliet thy love,
An hour but married, Tybalt murderèd,
Doting like me, and like me banishèd,
Then mightst thou speak, then mightst thou tear thy hair
And fall upon the ground as I do now,
Taking the measure of an unmade grave.

The Friar eventually reprimands Romeo for his words and points out his immature behavior. He says,

Hold thy desperate hand!
Art thou a man? Thy form cries out thou art.
Thy tears are womanish; thy wild acts denote
The unreasonable fury of a beast.
Unseemly woman in a seeming man,
And ill-beseeming beast in seeming both!

In the end the Nurse and Friar Lawrence fail in their roles as older role models for Romeo and Juliet. The Nurse gives Juliet bad advice about marrying Paris, forcing the girl to seek counsel from the Friar. The Friar fails in his plan for Juliet to fake her death as his message to Romeo is never received. In this case, the generation gap winds up being deadly for the young people.

What is Sjögren's syndrome?

Causes and Symptoms

Sjögren’s (pronounced SHOW-grins) syndrome is a chronic autoimmune
disease in which the body’s own immune cells attack and eliminate the glands that produce tears and saliva. This results in dryness of the eyes and mouth and is referred to as sicca syndrome. The causes of Sjögren’s syndrome are not known, although evidence suggests that viral infection, heredity, and hormones may be involved. Sjögren’s syndrome is one of the more prevalent autoimmune disorders. Nine of ten patients with Sjögren’s syndrome are female.

Sjögren’s syndrome can be difficult to diagnose because the symptoms are similar to those caused by other diseases. The symptoms can also mimic the side effects associated with a number of medications and may vary from individual to individual. Even when the symptoms are reported to a physician, dentist, or eye specialist, the proper diagnosis can be overlooked.

The classic symptoms are dry eyes
(xerophthalmia) and dry mouth
(xerostomia). Individuals with Sjögren’s syndrome often have blurred vision, constant eye discomfort, recurrent mouth infections, swollen parotid (salivary) glands, hoarseness, and difficulty in swallowing and eating. Dryness of other mucous membranes of the body, such as the intestines, lungs, and reproductive system, may also occur. Extreme fatigue can also seriously alter the quality of life.

Sjögren’s syndrome is most commonly diagnosed in people in their mid-forties. In some individuals, primary Sjögren’s syndrome affects only the tear ducts and salivary glands. In other patients, it is present in conjunction with other diseases such as rheumatoid arthritis, systemic
lupus erythematosus, systemic sclerosis (scleroderma), or polymyositis/dermatomyositis (secondary Sjögren’s syndrome).

Treatment and Therapy

Once Sjögren’s syndrome is suspected, blood tests for autoantibodies against nuclear or cytoplasmic proteins may be performed. Schirmer’s test, which measures tear production, and salivary scintigraphy, which determines salivary gland function, may also be performed. A lower lip biopsy, to determine the extent of inflammation, may also be needed.

Moisture replacement therapies are designed to ease the symptoms of dryness. The routine use of eyedrops aids in controlling dryness of the eyes, and saliva-stimulating drugs and salivary packets help with difficulties in chewing and swallowing food. For individuals with more severe complications, immunosuppressive or nonsteroidal anti-inflammatory drugs (NSAIDs) may be prescribed.

Perspective and Prospects

Sjögren’s syndrome is named after the Swedish eye doctor Henrik Sjögren, who first identified the syndrome in 1933. There is no known cure for Sjögren’s syndrome, nor is there a current treatment to restore gland secretion. The outlook for individuals with this condition is usually good because Sjögren’s syndrome is generally not life-threatening.

Bibliography

Carson-DeWitt, Rosalyn. "Sjogren's Syndrome." Health Library, Dec. 30, 2011.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Sjögren’s Syndrome. San Diego, Calif.: Icon Health, 2002.

Rose, Noel R., and Ian R. Mackay, eds. The Autoimmune Diseases. 4th ed. St. Louis, Mo.: Academic Press/Elsevier, 2006.

"Sjogren's Syndrome." MedlinePlus, May 22, 2013.

Teitel, Ariel D., and David Zieve. "Sjogren Syndrome." MedlinePlus, June 28, 2011.

Wallace, Daniel J., et al., eds. The New Sjogren’s Syndrome Handbook. 3d rev. ed. New York: Oxford University Press, 2005.

"What Is Sjögren's Syndrome?" National Institute of Arthritis and Musculoskeletal and Skin Diseases, July 2010.

Why might it be problematic for teachers to apply Atkinson’s theory of need for achievement in their classrooms?

John Atkinson, David McClelland, and their colleagues theorized that student motivation was unconsciously linked to early childhood experiences. For example, a child who was consistently punished for asking questions would have a low motivation to ask questions throughout the course of his or her lifetime. The problematic application of this theory lies in the underlying belief that individual need for achievement is limited and determined before the child enters the classroom. 

A teacher who applies Atkinson's Theory of Motivation on a long term basis may be able to gain an accurate knowledge of their students' current need for achievement. However, further research has shown that intelligence and motivation are not deterministic traits. Therefore, teachers could very well neglect the potential growth of a child's mindset if they apply Atkinson and McClelland's theory without considering current research in the field. 

What does "the city's broken roar" mean in the poem "Faces" by Sara Teasdale?

The phrase "the city's broken roar" in the poem "Faces" by Sara Teasdale means that although the exterior face of a city often exudes a countenance of strength and robust activity, it is not really the true face of the city because of the challenges of the people face who inhabit said city.

Consider what Sara Teasdale is saying in this poem when she conveys the message that people put on facades or wear disguises – facially – as they interact on the streets of a city and throughout the society they inhabit. This is evident in these lines in stanza two of this four stanza poem:

“How ashamed I am, and sad

To have pierced your poor disguise?”

Therefore, Sara Teasdale is saying here that there is a fragility to the city because of the everyday challenges that its citizens face. The city may try to put forth a roar, as if a powerful lion, however, the city is only as strong as its people. People wearied and embattled by life’s trials and disappointments cause a weakening of that proud roar, which becomes “the city’s broken roar.”

Teasdale states that the people of the city have secrets that are crying out from the hiding places that individuals have. These hiding places may be the sanctuaries of respite that people go to, so as to rest and recover from their everyday battles. In as much, this shows that the city may put on a brave face, but is the city actually brave when its citizens often lack the wherewithal to fight their daily battles, or seek to find solace or hide from them?

Teasdale writes that she:

 “…cannot bear

The sorrow of the passing faces.”

She recognizes “the city’s broken roar” in the faces of people. She recognizes the exterior show that people put on, while often hiding their true emotions so as not to appear weak to others. The poet writes that the street is restless. This concerns the people on the street, in a harried, modern, and fast-paced society not always at peace with itself.

Teasdale also recognizes that what she sees in others, they probably see in her as well. She is not immune to the pressures of life and faces exactly what others face in living life. She is part of that “broken roar” as well, trying to be strong, while facing significant challenges.

What is the California Psychological Inventory (CPI)?

Introduction

The California Psychological Inventory (CPI) is a paper-and-pencil test designed for a comprehensive analysis of traits that describe a normal adult personality. The test itself consists of 462 statements about feelings and opinions, ethical and social attitudes, personal relationships, and characteristic behavior. The testee responds to each item as “true” or “false.” Responses to these statements are analyzed, first of all, according to how well they fit twenty different patterns, each of which corresponds to a specified personality characteristic. The personality characteristics that are assessed include such everyday traits as sociability, dominance, independence, responsibility, self-control, tolerance, and achievement. The individual test-taker’s scores on each scale are evaluated by how these scores compare with the range of scores established by a nationwide comparison group or norm group. Such comparisons also permit evaluating the test-taker on three structural scales that summarize patterns underlying the twenty primary scales at a more abstract and basic level: externality-internality (self-confident assertive extraversion versus introversion), norm-favoring versus norm-questioning (allegiance to the conventional social rules versus its lack), and the degree of one’s “realization” of these tendencies, an index of self-fulfillment or satisfaction.

Development

Harrison Gough, the author of the CPI, began assembling items relevant to the measurement of everyday personality characteristics in the late 1940s. It was 1957, however, before the completed eighteen scales of the CPI were published by Consulting Psychologist Press. In 1987, modest revisions in the scale were initiated. At this time, a few items were modified to reflect cultural changes, and two new primary scales, independence and empathy, were added to the original eighteen. The most important change, however, was the addition of the three summary, structural scales.

Two important principles governed the CPI’s development. The first of these was Gough’s interest in measuring “folk concepts,” characteristics which in many cultures and over centuries made sense to ordinary people. This principle was in contrast to many existing tests that assessed concepts based on psychiatric diagnosis or academic personality theories or were abstracted from a mathematical procedure called factor analysis.

A second guiding principle was that of empirical criterion keying, which means that the validity of items on scales, as well as the scales themselves, should be established by actual research. In such research, items and scales are tested to assure that people who show evident differences in real-life functioning answer the item or the scale in the different ways one would expect. For example, the socialization scale was conceived to measure moral uprightness in the sense of observing society’s rules and customs. One would expect that convicted felons would answer questions on this scale in ways different from Eagle Scouts, and felons would be expected to score much lower on this scale. Research verifying this difference supported the validity of the item and the scale. Hundreds of such predictions derived from the meaning of various CPI scales were tested. Only thereafter was the test considered valid.

Evaluation

A major criticism of the CPI is that there is much overlap between highly similar scales. Dominance and capacity for status, for example, seem to involve only slightly nuanced measurements of almost the same thing. It has been argued, therefore, that the essential information could be gleaned from fewer, simpler scales. Gough answered this criticism by pointing out that everyday descriptions of others by ordinary folk also show this sort of overlap. He also pointed out that the structural scales, added in 1987, permit such simple, efficient description of a personality without depriving the test-taker of the refined and detailed analysis offered by assessing twenty primary traits.

It has also been charged that the CPI is often employed beyond the uses for which its validity has been established. Clinicians are prone to apply the test to abnormal populations for which validity data is incomplete. The test has also been frequently used for people from cultures outside the United States and for minorities within the United States. Although Gough selected his “folk concepts” for their apparent cross-cultural relevance, validity studies in minority and Third World subcultures have been neglected. Interpreting the test results of those from different cultural backgrounds must, therefore, be done with caution.

These admitted limitations could be addressed by adding more studies of minority or clinical populations to the already impressive research with this instrument. For more than half a century, the CPI has served such purposes as predicting vocational choice, academic success, and antisocial behavior. Few other personality tests have been as thoroughly validated. Its many scales permit a detailed description of a person in language that makes sense. Useful and much used, the CPI remains one of the best personality tests for normal populations.

Bibliography

Anastasi, Anne, and Susan Urbina. Psychological Testing. 7th ed. Upper Saddle River: Prentice, 1997. Print.

Bolton, B. “Review of the California Psychological Inventory, Revised Edition.” Eleventh Mental Measurements Yearbook. Ed. J. J. Framer and J. C. Conly. Lincoln: Buros Institute of Mental Measurements, 1992. Print.

Gough, H. G. “The California Psychological Inventory.” Testing in Counseling Practice. Ed. C. E. Walker and V. L. Campbell. Hillsdale.: Erlbaum, 1992. Print.

Gough, H. G., and P. Bradley. “Delinquent and Criminal Behavior as Assessed by the Revised California Psychological Inventory.” Journal of Clinical Psychology 48 (1992): 298–308. Print.

Groth-Marnat, Gary. Handbook of Psychological Assessment. Rev. ed. New York: Wiley, 2009. Print.

Kulas, John T., Richard C. Thompson, and Michael G. Anderson. "California Psychological Inventory Dominance Scale Measurement Equivalence: General Population Normative and Indian, UK, and US Managerial Samples." Educational & Psychological Measurement 71.1 (2011): 245–57. Print.

Megargee, E. I. The California Psychological Inventory Handbook. San Francisco: Jossey, 1977. Print.

Melton, Gary B., et al. Psychological Evaluations for the Courts: A Handbook for Mental Health Professionals and Lawyers. 3d ed. New York: Guilford, 2007. Print.

Nestor, Paul, and Russell K. Schutt. Research Methods in Psychology: Investigating Human Behavior. Los Angeles: SAGE, 2012. Print.

Reynolds, Cecil R., and Ronald B. Livingston. Mastering Modern Psychological Testing: Theory & Methods. Boston: Pearson Education, 2012. Print.

What is septic shock?

Definition

Septic shock is acute cardiovascular collapse precipitated by a complex
interaction between biochemical agents in the bloodstream and the body’s
immune
system as it attempts to respond to infectious agents.
Arterial hypotension persists despite adequate fluid resuscitation.
The circulatory system is unable to meet the metabolic demands of cells: delivery
of oxygen and nutrients and removal of waste products. Pumping and circulation
fail, leading to reduced tissue perfusion and organ dysfunction. Mortality
approaches 40 to 70 percent.

Causes

Infectious agents such as gram-positive and gram-negative bacteria, viruses, fungi, and yeast trigger an exaggerated immune inflammatory response. The lipopolysaccharide (LPS) shell on gram-negative bacteria is an extremely strong stimulator of systemic inflammation.

Risk Factors

Substantive risk factors include a compromised immune system, thermal burns,
malnutrition, extremes of age, chronic medical conditions, use of invasive medical
devices, hospitalization, steroid administration, and urinary tract, respiratory,
or abdominal infection. Recent research has demonstrated polymorphisms, mutations,
and dysregulation of cellular receptors that negatively affect the body’s
recognition of and response to pathogens.

Symptoms

Infection is heralded by fever, tachycardia, tachypnea, and
abnormal white blood cell count. Respiratory distress or frank respiratory failure
ensues. Myocardial depression, decreased cardiac output, and vasodilation lead to
hypotension refractory and fluid resuscitation and may require vasopressor and
hydrocortisone support. Peripheral pulses and capillary refill are diminished. A
procoagulant state develops in an attempt to prevent the dissemination of
pathogens, leading to coagulopathy and dermal petechiae and purpura. Renal and
gastrointestinal function diminishes.

Screening and Diagnosis

Diagnosis is incumbent on history, physical examination, clinical signs and symptoms, hematologic labs (blood culture, complete blood count, differential, immature to total neutrophil ratio, and serum lactate), acute-phase reactants and biomarkers (interleukin-6, adrenomedullin, C-reactive protein, and procalcitonin), and radiological evaluation of suspected source sites.

Treatment and Therapy

Elimination of the infection source is vital to survival. Culture and sensitivity testing of infected sites to identify the causative organism allows selection of definitive antimicrobial therapy. Until culture results are known empiric antibiotic therapy is required. Antibiotics should be administered within an hour of a diagnosis of sepsis. Newer microarray testing is allowing earlier identification of pathogens, leading to better definitive antibiotic therapy. Cardiovascular support includes adequate ventilation and oxygenation, vasopressor support, corticosteroids, and adequate hematologic parameters (platelets, red blood cells).

Prevention and Outcomes

Adequate nutrition, management of chronic illness, good handwashing technique,
aseptic
technique for sterile procedures, the avoidance of trauma or
exposure to infectious agents, and the removal of unnecessary tubes and catheters
in institutionalized and hospitalized persons reduces the incidence of infection
and thus lowers the risk of an exaggerated inflammatory response and shock
state.

Bibliography

Dellinger, R. Phillip, et al. “Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2008.” Critical Care Medicine 36 (2008): 296-327.

Evans, Timothy, and Mitchell P. Fink, eds. Mechanisms of Organ Dysfunction in Critical Illness. New York: Springer, 2002.

Klein, Deborah G. “Shock and Sepsis.” In Introduction to Critical Care Nursing, edited by Mary Lou Sole, Deborah G. Klein, and Marthe J. Moseley. 5th ed. St. Louis, Mo.: Saunders/Elsevier, 2009.

“Septic Shock.” MedlinePlus. Natl. Lib. of Medicine, 8 Feb. 2014. Web. 29 Dec. 2015.

Tissari, Päivi, et al. “Accurate and Rapid Identification of Bacterial Species from Positive Blood Cultures with a DNA-based Microarray Platform.” The Lancet 375 (January, 2010): 224-230.

Why does Winnie feel reassured when she hears the music box in Tuck Everlasting?

The music box reassures Winnie because it is pretty, and no one who owns something like that could really be all that bad.

The music box is one of Mae Tuck’s most prized possessions.  She finds in comforting and enjoys listening to it year after year.

Then she stood and took from the washstand beside the bed a little square-shaped object, a music box painted with roses and lilies of the valley. It was the one pretty thing she owned and she never went anywhere without it. (Ch. 2)

The music box is important because it is how the man in the yellow suit connects the spring to the Tucks.  She has had the music box for so long that he has heard its music described.  When they hear the music, Winnie’s grandma thinks it is elves playing, but Winnie thinks it is a music box.  The man in the yellow suit knows it’s not elves.  He thinks it is the music of the immortals.

Winnie finds the music box reassuring because it is pretty, and the music coming from it is pretty.  It reminds her of home, where she first heard it.

And then, after several more turns, the music began to play again, brisk from its fresh winding, and merry. No one who owned a thing like this could be too disagreeable.  Winnie examined the painted roses and lilies of the valley, and smiled in spite of herself. (Ch. 6)

The music box calms all of them.  It is soothing music and a distraction from their troubles.  Winnie is nervous because she has been “kidnapped” by people she does not know.  The Tucks are nervous because they are not sure how to explain everything to Winnie.  To most people, their tale of drinking from a spring in the woods and becoming immortal must sound strange.

Why did the Quit India Movement fail?

During World War II, Mahatma Gandhi led the Quit India Movement, a non-violent resistance against British rule in India. Gandhi hoped that, due to its military involvement in the war, Britain would capitulate and give India self-rule.

However, the Quit India Movement failed because its leaders did not present a clear plan of action and some supporters began to enact violence against buildings owned by the British government. Additionally, Great Britain acted swiftly to suppress the revolt, even going to so far as to imprison most of the India National Congress for most of the remainder of World War II. Britain also imprisoned as many as 100,000 Indian nationals for supporting the movement.

Nevertheless, the Quit India Movement may have contributed to the British government's eventual pull-out from India. They feared additional protests which would perhaps be even more violent. Thus Britain--weakened by World War II--decided that governing India was more trouble than it was worth. 

Explain the theme of loss as it is illustrated in Othello.

Loss is presented in a number of different forms in the play. At the beginning of the play, we become aware of Iago's failure to attain a promotion. He loses the opportunity for betterment and a title which would afford him greater status and authority. He is bitterly resentful toward Othello, his general, for denying him the opportunity to improve his situation and tells Roderigo:

And I, of whom his eyes had seen the proof
At Rhodes, at Cyprus and on other grounds
Christian and heathen, must be be-lee'd and calm'd
By debitor and creditor: this counter-caster,
He, in good time, must his lieutenant be,
And I—God bless the mark!—his Moorship's ancient.

Iago's bitterness is born from the fact that he felt he deserved the appointment since he had been loyal to the general. He had fought by his side and was an experienced soldier. He is angry at Othello's audacity in appointing an inexperienced outsider, Michael Cassio, in his stead, even though three senators had made an appeal on his behalf.

This decision informs Iago's desire for revenge, and he tells Roderigo that he will appear loyal to his general, for:

I follow him to serve my turn upon him . . . 

Appearing loyal will give him an opportunity to take revenge, for Othello will not suspect him of any malice.

The issue of loss is also evident in the character Brabantio. He has been a doting, loving and possessive father to his beautiful daughter, Desdemona. When Othello and she elope, he is devastated, especially since Iago and Roderigo had painted a maliciously lurid picture of Othello with her, using animal imagery and stating that the general had abducted her and was abusing her.

Brabantio is absolutely distraught when Desdemona later chooses Othello over him. She tells her father:

...I am hitherto your daughter: but here's my husband,
And so much duty as my mother show'd
To you, preferring you before her father,
So much I challenge that I may profess
Due to the Moor my lord.

He feels betrayed and later tells Othello:

Look to her, Moor, if thou hast eyes to see:
She has deceived her father, and may thee.

This comment serves to plant a tiny, pernicious seed in Othello's mind which later informs his thinking and the devastating results thereof. We also later discover that Brabantio has died of a broken heart brought on by what he believed to be Desdemona's treason.

Othello experiences loss. He loses his trust in Desdemona and loses her. He loses his self-control, his sanity, his integrity and, eventually, his life. He loses all these because he is gullible enough to trust the malevolent Iago and, like a fool, is manipulated by him. Iago convinces him that his wife is having an affair with his handsome lieutenant and presents him with all kinds of made-up proof of her deceit. The general swears revenge and first plots with Iago to have his lieutenant murdered, and he eventually kills her. Cassio escapes his wrath, but is injured in the process.

The depth of his loss is expressed by Othello himself, at the end of the play:

. . . then must you speak
Of one that loved not wisely but too well;
Of one not easily jealous, but being wrought
Perplex'd in the extreme; of one whose hand,
Like the base Indian, threw a pearl away
Richer than all his tribe . . .

Michael Cassio loses not only his position as lieutenant, but also his reputation. He, too, is a victim of Iago's manipulation and is coerced into drinking alcohol by the sly ancient. Since he is easily inebriated, he later gets into a brawl with Roderigo (all planned by Iago) and a confrontation with Montano. Othello is awoken by the noise and, after an "honest" report of the incident by Iago, dismisses Cassio. Cassio is overwhelmed and distraught and later painfully cries out:

Reputation, reputation, reputation! O, I have lost
my reputation! I have lost the immortal part of
myself, and what remains is bestial. My reputation,
Iago, my reputation!

Iago, who, one feels, should be the one who loses most because of his perfidy, actually wins more than he loses. He got his revenge, for both Othello and Desdemona are dead. He ensured Cassio's dismissal, although he is later appointed to Othello's position. Although he loses Emilia, he is entirely responsible, for he killed her for what he believed was her betrayal. He loses his freedom and will face justice, but one cannot help but feel that his punishment can never be enough for the devastation he has caused. Lodovico says of him:

. . . For this slave,
If there be any cunning cruelty
That can torment him much and hold him long,
It shall be his. You shall close prisoner rest,
Till that the nature of your fault be known
To the Venetian state. Come, bring him away.

Desdemona also suffers great loss. She loses Othello's trust and later her life. She also loses her father in that he rejects her for her marriage to Othello, and her loss is emphasized when he later dies of a broken heart. More devastatingly, though, she loses her life at the hands of the one she loved and trusted the most, her first and only love, Othello.

One may also refer to other losses: Roderigo loses his money, integrity, self-respect, and he loses the chance to ever engage with Desdemona. He also loses his life at the hand of Iago, who had made him his puppet. Furthermore, there is the loss regarding Emilia. In trying to please Iago, she lost some of her integrity, for she stole her mistress' handkerchief and later lied to her about it. There is also the loss that Bianca, who was infatuated with Cassio, suffers. She eventually falls out with him because of the incident with the handkerchief.