Abstract This paper looks at chromatography, an analytical technique based on the principle of selective adsorption that is used for the chemical separation of mixtures and substances. It examines how it is an important field of chemistry, which deals with the separation of pure substances from complex mixtures, and is widely used in the analysis of foods, drugs, blood, petroleum products, and radioactive-fission products. It also examines how variants of "column" chromatography have been developed since its discovery in 1906, including partition, liquid, paper, thin-layer, and gas-liquid chromatography.
From the Paper "Chromatography was discovered in 1906 by the Russian botanist Mikhail Tswett who first coined the term (derived from the Latin for "color writing"). The technique used by Tswett for separating the pigments (chlorophyll) of plants consisted of pouring petroleum-ether extract of green leaves over a column of powdered calcium carbonate in a vertical glass tube. As the solution seeped through the column the individual components of the mixture moved downward at different rates of speed, and the column became marked with horizontal bands of colors. Tswett did not enjoy a happy relationship with fellow scientists of his time, as they derided his results, and his technique, with Tswett responding in kind. As a result, it wasn?t until the 1930s that his methods were accepted as a breakthrough in chromatography."
Compares the Salem witch trials to the experience of those in modern society who are attempting to break into a career field dominated by one particular caste.
Abstract This paper compares at the experience of women accused of witchcraft in Europe in the 17th century to the experience of women in contemporary society trying to break into the field of science. The paper contends that women of the 17th century, who practiced medicine through their knowledge of herbs and natural healing methods, were perceived as a threat to the male-dominated field of medicine and society at large. It is also argued in this paper that women in science today are faced with the same set of beliefs and barriers that held the women of the 17th century back from their equal status.
From the Paper "Whenever one group of people obtain a majority interest in social order over another particular group, or over all other groups, the cries of outrage and abuse will soon be heard from both the dominant and the oppressed. The oppressed people of the group often have a legitimate point of contention. Possibly they were not the fastest to secure economic prominence, and therefore as the poor, they now need assistance to keep up with the leaders. Perhaps they simple lost a number of competitions, and became the follower rather than the leaders. In any case, those who are now in the position of following eventually begin to question the established social order. In order to bring about change, they often cry "discrimination" or "prejudice" of some other emotionally charged epithet in order to gain the public's support for their self induced plight."
Tags: social, order, authority, trial, religious, leaders, scientists, scientific, community
Abstract This paper examines polarity, the unequal distribution of charges, and how bond formation and, hence, compound formation largely depends on it. It looks at how all properties of chemical compounds largely stem from their relative polarities and how life would not exist without elemental polarities. It provides a basic explanation of the different types of bonding between elements, such as ionic and covalent, as well the importance of these bonds in the creation of biochemical structures, such as proteins and DNA.
From the Paper "Therefore, any molecule or ion (simple of complex) that has an internal unequal distribution of charges is a polar molecule. This is the definition of polarity. Since bond breaking or bond formation and chemical reactions occur by means of electron transfer, the availability (or lack thereof) of electrons and the ease in which one bond can break and another form depends on the polarities of the compounds involved. Every chemical reaction and every pharmaceutical product created depends on polarities and electron density distributions. Here is an example of electron transfer: nucleophilic substitutions reactions."
Tags: ionic, covalent, dna, protein, ion, electron
Abstract This study provides a discussion of silica, the evolution of crystalline silica dust exposure concerns, an overview of the various uses of crystalline silica in the workplace, a summary of the various governmental regulations and standards that currently govern crystalline silica in the workplace, and the International Agency for Research on Cancer (IARC) evaluation process for classification of silica, a discussion of how the presence of crystalline silica is currently determined and measured in the workplace, as well as what can be done to protect workers from exposure to this hazardous material. Additionally, the various health risks resulting from crystalline silica exposure are discussed, including the relationship between crystalline silica exposure and the incidence of silicosis, cancer, and various autoimmune disorders. Finally, the specific dangers of exposure in the construction industry and among heavy-equipment operators are explored, and the growing body of legal actions resulting from crystalline silica exposure is discussed.
Contents
Introduction
Problem Statement
Purpose of Study
Importance of Study
Scope of Study
Rationale of Study
Definition of Terms
Overview of Study
Review of Literature
History of Crystalline Silica Exposure
Use of Crystalline Silica
Measurement of Crystalline Silica
Determining the Presence of Silica in the Workplace
Measuring Workplace Exposure to Crystalline Silica
Protection Against Crystalline Silica
Silicosis Resulting from Crystalline Silica
The IARC Evaluation Process
IARC Classification of Silica
Amended IARC Evaluation of Silica as a Carcinogen
Crystalline Silica and Autoimmune Diseases
Exposure to Silica in Construction
Exposure to Silica Among Heavy Equipment
Exposure to Silica in Sandblasters
Legal Actions
Death in the Workplace
Regulation
OSHA's Hazard Standard
Relevant OSHA Regulations
Methodology
Approach
Data Gathering
Database of Study
Validity of the Data
Originality & Limitations of the Data
From the Paper "Silicon is classified as a nonmetal, but it has many of the properties that are associated with metals. Some scientists refer to this type of an element as a metalloid. Silicon acts like a metal and conducts electricity at high temperatures, but at low temperatures, it behaves more like an insulator and does not conduct electricity. Therefore, it is referred to as a semiconductor. This particular property is what made silicon the perfect element to propel technology into the world of transistors, then integrated circuits, and finally today's computer chip (Boegel, 1968).
Silica is a chemical compound, as opposed to an element, and is formed from silicon and oxygen atoms. A chemical compound is defined as "a distinct and pure substance formed by the union of two or more elements" (USGS, 1992, p. 3). Due to the abundance of the elements of oxygen and silicon, the natural formation of silica is quite common. Silica sand, the substance from which pure silicon is derived, is made of quartz. Quartz is the most common form of silica found in nature."
Abstract This paper is a technical report on a laboratory experiment on surface tension measurements using the Du Nuoy ring. Samples are pure water, ethanol solution, and 1.5N NaCl. Calculations for the correction factor and other necessary values are included in the discussion.
From the Paper "The Du Nuoy ring is the most commonly used apparatus for surface tension measurements. The group used pieces of paper to determine the weight needed to depress the lever arm to zero. For the experiment proper, the ring was thoroughly cleaned and flamed to red heat for a few seconds. The vernier was turned to zero reading and the lever arm made to just touch the zero indicator. The ring was made to contact the surface of the liquid and was carefully submerged until good contact is established. This was then slowly recovered from the liquid by careful downward movement of the platform and of the thumbscrew. It is important that the lever arm is kept at the zero indicator until the ring is detached from the liquid."
Abstract This paper uses explanations and many technical chemistry terms. It is written using a lot of chemistry terminology, but maintains a coherent voice. The paper covers how steroids used to be administered, why newer steroids are given the way they are, and what the advantages are to the different types of drugs and delivery methods.
From the Paper "The new technology in prohormones hitting the market are Lipophilic ester and ethers, and are being touted as the first truly effective solutions to the poor oral bioavailability of many such supplements. And there is a tremendous amount of promise with this technology if properly applied. Supplement manufacturers have been looking for a solution to problems with oral dosing for some time, and they knew they had a true advance on their hands in this area. Chemists went through great lengths not to just drop powder into a capsule, but to develop a series of ether-modified, oil-solubilized, softgel-encapsulated prohormones."
This paper discusses that, while modern day discoveries of new carbon allotropes are reported, the characterization of allotropy remains ambiguous as the definition of what constitutes an allotrope is under debate.
Abstract This paper explains that the linear sp carbon of Lagow's proposed length and structure is contradicted by the unlikelihood of such a stable, long chain allotrope, granting more validity to Hirsch's argument against the existence of Lagow's carbon allotrope. The author points out that controversy arises because, while they do not directly fit the definition of allotropes, non-molecular allotropes like diamond and graphite will terminate with other elements (so no longer a pure element) to become stable. The paper concludes that future scientific work in this area is required to determine a true carbon sp allotrope of usable stability, if one exists, but at this time, Hirsch's position remains the more plausible basis of allotropic characterization.
From the Paper "The IUPAC Red Book defines allotropes as ?different structural modifications of [an] element,? with allotropic transition considered the "transition of a pure element, at a defined temperature and pressure, from one crystal structure to another which contains the same atoms but which has different properties". This definition excludes ozone and oxygen, and does not discuss the classification of carbon allotropes, which can be examined on the basis of the hybridization of their valence orbitals. More modern definitions include the classification of tin where one allotrope is a covalently bonded solid and the other a metal, and differentiate between allotropic molecules, such as dioxygen, infinite covalent solids, like diamond, and infinite, covalently bonded layers with weak intermolecular forces, as seen with graphite. There are also materials that crystallize where the covalent bonding between the elements is unchanged, which are termed polymorphs rather than true allotropes."
Abstract This paper relates that lactose, an important and well-understood component of milk, provides an important source of nutrition during development, and, for individuals without lactose intolerance, milk often continues to be an important part of a healthy and varied adult diet. The author points out that lactose intolerance is a common issue for much of the world's population, especially people of Asian and non-Western European decent, but a large number of Europeans can easily digest lactose. The paper relates that, in the Western society, lactose (within milk) is used within a wide variety of milk products, such as cheeses, cottage cheese, sour cream, and yogurts; in addition, milk is used in a wide variety of other food products, including breads, pizzas, ice cream products, and even cereals.
From the Paper "In structure, lactose is a white crystalline disaccharide that is comprised of two sugars that are bound together: glucose and galactose. Glucose and galactose are monosaccharides. Lactose has the same chemical formula as sucrose and maltose (C12H22O11). However, lactose differs from sucrose and maltose in structure. When hydrolyzed, lactose yields D-glucose and D-galactose. This hydrolysis is catalyzed by lactase within the digestive tract (Miller). Thy hydrolysis of lactose results in increased sweetness and a depression of the freezing point of milk."
Abstract This paper examines the fact that issues of gender continue to strongly influence both scientific literature and the practice of science today. Based on notions of gender that developed during the enlightenment and the Victorian era, the paper explores science's long history of incorporating gender norms and sex dichotomies into science.
From the Paper "Notions of gender have influenced the historic development of science in the west, as reason and science have long been seen as male traits. Similarly, gender ideals such as the characterization of females as maternal, associated with nature, irrational, and week have been reflected in scientific literature. Today, science continues to be influenced by ideas of gender, as literature reflects gender biases, and female scientists routinely must challenge gender biases."
Abstract This paper describes the early belief in spontaneous generation, the theory that living things could originate from non-living matter. It then takes a look at the scientific experiments responsible for finally putting this belief to rest. The paper also describes a laboratory experiment, performed by the paper's author, that delivers results, which concur with the previous experiments mentioned.
From the Paper "For many centuries people believed that living things could originate from nonliving matter. This belief is known as spontaneous generation, or abiogenesis. It was a commonly held belief in Ancient Rome, during the Middle Ages, and even until the late nineteenth century that spontaneous generation, or the sudden generation of complex life from nonliving matter, existed. (Evers, 1999) Scientists began to question this theory as early as the second half of the seventeenth century, but it was not until almost 200 years later that Louis Pasteur definitively disproved spontaneous generation and changed the course of scientific thought. While it is still debated whether any forms of abiogenesis, or the generation of even simple or microscopic life from nonliving matter, could be possible (Wilkins, 2004), it is certain that spontaneous generation involving complex life forms is not possible."
Abstract This paper analyzes the fundamentals of the large and complex body of information already collected and still in progress on the subject of G protein-linked receptors. The paper highlights the basic nature of G protein-linked signaling and explains how physiological regulation occurs through particular mechanisms.
From the Paper "Cells in multi-cellular organisms, like animals, need to communicate among themselves in directing and regulating growth, development and organization (Altruis Biomedical Network 2003). Such communication modes include secreting chemicals that signal to distant cells, display cell surface chemicals that influence other cells in direct physical contact, and directly through porous cellular points called gap junctions (Altruis Biomedical Network). Endocrine signaling demonstrates the first mode, wherein hormones are secreted in the bloodstream to distant target cells. Paracrine signaling illustrates the second mode, wherein local chemical mediators are secreted and act only on cells in the proximate environment. And synaptic signaling exhibits the third mode, wherein molecules are released by vesicles at those junctions called synapses. The molecules are neurotransmitters that spread out and act only on the postsynaptic target cell (Altruis Biomedical Network). Protein receptor molecules that are on or within the target cells bind to the hormone, paracrine or neurotransmitter and a response results, depending on the speed and selectivity of the delivered signal."
Abstract This paper highlights the causes and effects of the compulsory licensing of pharmaceutical products. The paper discusses the fundamental positions, attitude, inclination, and concerns of the developed world and the under-developed world with regard to the intellectual property rights of the pharmaceutical products. The paper also concentrates on the subject of the intellectual property rights of the biotechnology products. The paper also exposes the priorities of both the developed world and the under-developed world, priorities that have been a major hurdle in all previous negotiations on Intellectual Property Rights (IPR) protection. Subsequently, the paper gives practical recommendations that ought to be followed in all future negotiations so that both parties can derive maximum benefits from the patentability of pharmaceutical products.
From the Paper "Over the years, it has become a general belief that biodiversity will pave the way for a solution to almost all the diseases that exist today and continue to negatively influence our lives. This belief has led scientists to take further steps in the Research and development (R&D) of biotechnology. These steps comprise of various compounds, compounds that are biologically active, compounds that are natural resources, for example microbes, insects, fungi, marine organisms, and plants. However, laboratories are not capable of producing these complex biologically active and complex compounds. This is because the key places of genetic biodiversity are situated in the tropical and the subtropical regions of the world (Tara, 1994). Therefore, it is imperative for biotech scientists to go into the tropical forests with the purpose of locating these biologically active compounds."
Abstract This paper describes the pain-killing medication, Celebrex, including its functional groups and solubility. This paper also talks about some of the diseases Celebrex helps control, as well as the medication's possible side effects.
From the Paper "There has been much controversy the past couple of years about COX-2 inhibitors. These drugs are currently either being taken off the market or given strict caution labels. This is due to a higher risk of heart attacks and strokes. One of these COX-2 inhibitors that are coming up in discussion is Celecoxib. This drug is better known by its brand name, Celebrex."
Scientific review of journal article, "Determination of Safety Levels of Horseradish Peroxidase-Iodide System to Human Gingival Keratinocytes and Fibroblasts in Vitro" .
Abstract This paper explains and reviews an article about the effects of the horseradish peroxidase-iodide system on metabolic activity, membrane permeability, and cell growth of gingival keratinocytes and fibroblasts in vitro. The paper provides background information on the subject of the article, details the results of the experiment under discussion, and explains the significance of the experiment in terms of future research on the subject.
From the Paper "Collectively, these results demonstrate that of the three studied cellular indicators the effects of the complete HRP-I system were first observed as decreased metabolic activity and cell growth. Keratinocytes cell membrane permeability was altered only with concentrations of iodine and hydrogen peroxide as high as 25mmol/L in the complete HRP system in growth medium. The highest production of free iodine was measured to be by the HRP-I system in buffer compared to the growth medium. This is due to the presence of oxidizable free amino acids and antioxidants in the growth media. The highest concentrations of the HRP-Iodine system components which did not have any significant detrimental effects on the metabolic activity and cell growth of gingival keratinocytes and fibroblasts with exposure time as long as 1 hour did not have detrimental effects on the metabolism of HGK and HGF cells if the exposure time did not exceed 5 minutes. The effects of the HRP system on cell growth and metabolic activity were observed at lower iodide and hydrogen peroxide concentrations than its effects on membrane permeability. Gingival fibroblasts were more prone to detachment than keratinocyte cell lines, but no differences in changes of growth or metabolic activities were observed between gingival fibroblasts and gingival keratinocytes."
Abstract This paper examines how trans-fatty acids (TFAs) are lipids that have been chemically manipulated to become more solid at room temperature. In particular, it looks at how they are broken down by the body and how they can be a cause of heart disease.
From the Paper "Dietary fatty acids are emulsified by bile acids in the small intestine and transformed into chylomicrons which enter the bloodstream via the lymphatic system. Fatty acids are also taken up by cells, where they may serve as fuels for energy production. Chylomicrons can have two outcomes depending upon the body's need for energy, either being stored or oxidized. The oxidation of fatty acids produces acetyl-ScoA, which is the platform for cholesterol synthesis. Excess cholesterol can be stored or deposited on the walls of arteries, narrowing them. The stored fatty acids, as triacylglycerol (triglyceride) in white adipose tissue, also results in the formation of acetyl-ScoA, but through a different pathway."
