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Solar Cells, 2001.
A look at solar cells and the technology behind them.
1,210 words (approx. 4.8 pages), 5 sources, MLA, $ 41.95
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Abstract
This paper defines what solar cells are, how they are created and the technological history behind their development. It provides scientific theories to support this information and explains the uses of solar cells in today's technology.
From the Paper
"A solar cell is any device that directly converts the energy in light into electrical energy through the process of photovoltaics. Unlike batteries or fuel cells, solar cells do not utilize chemical reactions to produce electric power, and, unlike electric generators, they do not have any moving parts. Solar cells are also called solar batteries and, as the term solar implies, they are in most cases designed for converting sunlight into electrical energy.
"In the basic structure of a typical solar cell, light enters the device through a layer of material called the antireflection layer. The function of this layer is to trap the light falling on the solar cell and to promote the transmission of this light into the energy-conversion layers below. Such materials as silicon oxides or titanium dioxide are employed as the antireflection layer in solar cells."
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Solar Cell Manufacturing Process, 2008.
An analysis of the steps involved in the process of solar cell manufacturing.
968 words (approx. 3.9 pages), 5 sources, MLA, $ 34.95
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Abstract
This paper discusses the process of solar cell manufacturing and looks at each step of the process in detail. The paper describes the processing stages of chlorine-free polysilicon production and describes the purity requirements for the silicon used in solar cells. The paper also briefly looks at the changes in the solar cell manufacturing industry over the past few years.
From the Paper
"The very last step of manufacturing a solar cell is adding the electrodes (electrical contacts) and interconnection strips. Electrical contacts connect each solar cell to another, creating a solar panel, and then to the receiver of the produced current. The contacts must be very thin (at least in the front) so as not to block sunlight to the cell. Metals such as silver, nickel, or copper are vacuum-evaporated through either a photo-resister, silkscreen, or they can be deposited on the exposed portion of cells that have been partially covered with wax. All three methods involve a system where the part of the cell on which a contact is not desired is protected, while the rest of the cell is exposed to the metal. And finally, the interconnection strips are soldered into place. Flux is applied to cell interconnection strips before soldering to act as a deoxidizer. It ensures better adhesion between the solder and solar cells. This provides positive contact for an electrical current and greatly lowers the probability of the current shorting out. After applying the solder and flux, the cell surfaces need to be cleaned with a chlorofluorocarbon compound."
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Solar Energy and Solar Cells, 2003.
This paper is on solar energy, solar cells (panels) and the breakdown of what happens in the process.
1,137 words (approx. 4.5 pages), 3 sources, MLA, $ 39.95
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Abstract
This paper provides a full explanation about the way in which solar energy is created. The paper looks at the process in details and then discusses what benefits solar energy may have in the future.
From the Paper
"Solar Energy comes from Solar cells which today are mostly made of silicon, one of the most common elements on Earth. The crystalline silicon solar cell was one of the first types to be developed and it is still the most common type in use today. They do not pollute the atmosphere and they leave behind no harmful waste products. Photovoltaic cells work effectively even in cloudy weather and unlike solar heaters, are more efficient at low temperatures. They do their job silently and there are no moving parts to wear out. It is no wonder that one marvels on how such a device would function. To understand how a solar cell works, it is necessary to go back to some basic atomic concepts. In the simplest model of the atom, electrons orbit a central nucleus, composed of protons and neutrons."
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Photovoltaic Cells and Solar Thermal Power Plants, 2005.
A comparison of photovoltaic cells and solar thermal power plants.
2,700 words (approx. 10.8 pages), 4 sources, $ 106.95
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Abstract
This paper compares two technologies, photovoltaic cells and solar thermal power plants, both providing energy from solar radiation, but by different means and in different degrees. It looks at how the photovoltaic cell is used in limited situations for powering small appliances and how solar thermal power plants are able to produce much more energy for use on a widespread basis by consumers, industry and entire countries. The relative costs are noted, along with economies that will be realized once these systems are more widely used.
From the Paper
"This report summarizes two related technologies, the photovoltaic cell and the solar thermal power plant, both methods of producing energy from solar radiation. The photovoltaic cell is used in limited situations for powering small appliances, and solar thermal power plants are able to produce much more energy for use on a widespread basis by consumers, industry, and entire countries. The relative costs are noted, along with economies that will be realized once these systems are more widely used. Introduction One of the great unknowns in American energy policy remains the extent to which solar energy in its various forms will contribute to the nation's energy supply in the future. After the oil, embargo in 1973, considerable interest was expressed in solar energy as a potential way of producing energy and of reducing dependence on foreign oil. "
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T- Cell B-Cell Collaborations in the Immune System, 2001.
A descriptive overview of the vertebrate adaptive immune response to both intra and extra-cellular pathogens with explicit focus on T-cell B-cell collaboration and antibody response.
1,425 words (approx. 5.7 pages), 9 sources, APA, $ 47.95
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Abstract
This paper covers the major pathways by which foreign antigens are identified and dealt with through the adaptive immune response which is paramount on B-cell and T-cell responses and interaction with one another in distinct pathways and steps. It includes several diagrams and their explanations of antigens, B-Cells, T-Cells, APC's and more and their interactions and processes they go through.
From the Paper
"All immune responses involving T-cell B-cell collaborations follow distinct pathways of interactions and development. These very pathways of the adaptive immune response are almost entirely dependant on the cellular interaction of B- cells and T- cells with one another. It is within each stage of these pathways and the progression of an adaptive immune response that we will concern ourselves. The following is a condensed synopsis of the adaptive immune response and the cellular interactions that will be the emphasis of this paper. Within secondary lymph tissues foreign antigen is presented to naive B-cells via their surface immunoglobulins (Igs) receptors. The same antigen is also presented to naive T-cells at this time. This presentation and subsequent recognition of antigen by both types of cells results in and end product of proliferation and development of naive B-cells into plasma cells whose function is the production of soluble immunoglobulins (antibodies), and the differentiation and development of memory B-cells whose function is to respond to subsequent exposure to the same antigen. However, this pathway is not self-sufficient and requires the direct interaction of activated T-cells, specifically ?helper? T-cells (Th2 cells) 1,9. It is these T-cells in conjunction with the antigen presenting B-cells that interact to produce a hormonal response to infection. These interactions activate Th2 cells that in turn promote B-cell activation both through T-cell secreted cytokines, (interlukeinI1-2, 4 and 5), and also through direct cell to cell contacts involving specific surface proteins and corresponding receptors and the signaling initiated by the binding of these proteins to one another."
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Stem Cells, 2006.
An overview of the nature of stem cells, stem cell research, and the controversy surrounding the use of stem cells from human embryos.
675 words (approx. 2.7 pages), 3 sources, $ 26.95
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Abstract
The different types of stem cell research involve the use of human eggs - and embryos - as intermediates and are at the center of controversy as to whether it should be considered human life. Recent advances are attempting to produce non-embryonic stem cells as well as address the said issue. This paper discusses the nature of stem cells, what they are, how they are produced and the issues surrounding them.
From the Paper
"Stem cells are undifferentiated cells that have the potential to develop and proliferate into more specialized cells such as neurons or skin cells. These specialized somatic cells comprise the different tissues and organs of the human body. The cloning process currently in use involves the use of the cellular machinery of an egg cell and the genetic material encoded in the nucleus of a somatic cell called somatic cell nuclear transplant (SCNT). First, the egg cell is secured to stabilize it. A needle is inserted into the egg to extract the nucleus and DNA."
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Stem Cells, 2002.
This is a persuasive essay on the use of stem cell research and how the cells are derived.
2,155 words (approx. 8.6 pages), 0 sources, MLA, $ 67.95
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Abstract
This paper discusses the controversial issue of stem cell research in the U.S. It conveys the negativity of using human embryos, but also expresses the positive uses of adult stem cells. The author includes remarks made by President George W. Bush, numerous quotes and reference pages and websites.
From the Paper
"The issue of using stem cells (embryonic and adult) is a heated debate among many citizens of the United States. Many people are against all types of research, but do not understand what it is about or what the research can be used for. There are many points that need to be made so people will know that not all stem cell research is harmful, or destroys human life. Embryonic stem cell research can be, and should be avoided, especially when there are other options available to us. Adult stem cell research is an available option that is being used in all parts of the world to find new discoveries. Once society agrees to certain forms of research, scientists may be able to use the research to obtain cures for numerous diseases."
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Cloning Embryonic Stem Cells, 2005.
This paper discusses, from a neutral position, ethical arguments either for or against the cloning of embryonic stem cells.
4,710 words (approx. 18.8 pages), 23 sources, APA, $ 121.95
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Abstract
This paper explains that embryonic stem cells are self-renewing, undifferentiated cells that are extracted from the inner cell mass of a 5-6 day old embryo or blasto-cyst, which destroys the embryo in the process of extracting the stem cells. The author stresses that the basic problems in embryonic stem cell research are the very highly valued moral problems it presents: (1) The prevention or alleviation of suffering and (2) the respect of human life. The paper stresses that the argument for and against cloning embryonic stem cells is also an argument as to the meaning of life and the recognition of the loss, at any point in life, of inevitable death.
Table of Contents
Introduction
What is Embryonic Stem Cell?
The Basic Problem
Arguments Presented For and Against Cloning Embryonic Stem Cells
Conclusion
From the Paper
"To endorse any use of the human embryo which was not consistent with a reverence for human life would be widely regarded as wrong. Those who believe that therapeutic research on embryos is ethically permissible, might argue that the creation and use of a human embryo outside the context of human reproduction does not necessarily undermine the attitude of respect for the human body and human dignity, provided that the purposes involved in such creation and use are purposes which we would recognize as beneficial ones. Medical uses fall into this category. In this view, it would appear to be quite consistent with an attitude of respect for human life to allow the use of human embryos at an early stage of development, well before the stage at which anything resembling a self can be said to come into existence. Such use promises to provide the possibility of the relief of a great deal of human suffering, a goal which in no sense calls into question respect for the human body."
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Stem Cells, 2004.
This paper discusses stem cell research, one of the most truly revolutionary medical science developments.
1,755 words (approx. 7.0 pages), 10 sources, APA, $ 56.95
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Abstract
This paper explains the potential benefits of stem cells result from the fact that they can transform themselves into literally any cell in the body, thus replacing the injured or damaged organs, which will render today's medicines obsolete. The author points out that there are formidable challenges to be overcome; the most serious is the 'ethical' opposition to stem cell research led by pro-life advocates who consider the use of embryos for creating stem cell lines as the killing of potential human beings. This has resulted in restriction of federal funding for stem cell research. The paper states that there are several formidable scientific barriers, such as the tendency of the immune systems to attack transplanted cells, which have to be crossed; therefore, the author believes that stem cell research deserves full support.
Table of Contents
Introduction
Types of Stem Cells
How Are Stem Cell Lines Created?
Sources of Stem Cells for Research Purposes
Fertility Clinics
Aborted Fetuses
Cloning
Made to Order
The Ethics of Stem Cell Research
Arguments Against Stem Cell Research Arguments for Stem Cell Research
Other Ethical Concerns
Issue of Federal Funding
Conclusion
From the Paper
"One of the most dramatic breakthroughs in the history of biological research occurred in November 1998, when two independent teams of American researchers managed to isolate and grow a special kind of human cell called the stem cell. Until then, scientists had struggled long and hard to isolate the elusive cells but capturing them had proved difficult. One reason for this difficulty was that most stem cells only exist in their original form for a short time before turning into the various specialized cells of the body; the other was that the cells need a highly specialized environment to keep them alive outside the body. Other scientists had previously succeeded in culturing stem cells for only short periods; the 'breakthrough' accomplishment was that the pioneering scientists successfully created conditions under which the stem cells could replicate over time without specializing."
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Stem Cells, 2004.
This paper discusses one of the most controversial topics of popular discourse, stem cell research.
2,055 words (approx. 8.2 pages), 3 sources, MLA, $ 64.95
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Abstract
This paper explains that stem cells intended for use in human applications are harvested from humans, umbilical cords, and embryos, and are so valuable because they are master cells with the capability to produce or ?become? any other cell type. The author points out that the reason for the discourse surrounding the topic of stem cells is the fact that the most promising source of stem cells is human fetal tissue; thus, many who hold anti-abortion views find this practice to be highly immoral and repugnant. The paper relates that the problem with umbilical cord stem cells is the small amount that can be harvested from any particular cord; adult stem cells, which pale in comparison to the ability of embryonic cells to differentiate into specialized cells, can be used for research.
From the Paper
"Of course, most people know the origin of human life begins with the sperm fertilizing the egg. After this, a single cell is created that holds all of the genetic information needed to form the entire human body. This cell divides and redivides over several days until these cells (known as totipotent, or as having ?total potential?) begin to specialize into the formation known as the ?blastocyst,? which has a hollow sphere of cells, and a cluster of inner cells (the inner cell mass). While the outer cells of this blastocyst proceed to form the placenta, the cells within the inner cell mass go on to form virtually all of the tissues and organs of the human body. It is these cells that are harvested to research stem cells."
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Stem Cells Research, 2002.
A look at the make-up of stem cells and their use in the medical sphere.
1,883 words (approx. 7.5 pages), 6 sources, MLA, $ 60.95
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Abstract
This paper begins by looking at the properties of stem cells and examines the phenomenon of stem cells, which provide limitless division and the rise of differentiated progeny. It then asks what embryonic stem cells are and looks at how they are cultured in the laboratory. It then discusses adult stem cells and the use of cell therapy today. The paper concludes with expectations for the future.
From the Paper
"Stem cells can be defined as progenitor cells or primitive cells that give rise to other cells. They are totipotent cells also dubbed as the ?master cells? of the body as they contain all the genetic information needed to create all the cells in the body plus the placenta, which nourishes the human embryo. Human cells have this capacity only during the first few divisions of the fertilized egg. Totipotent cells follow a series of stages and become highly specialized after 3-4 divisions. The next stage of division give rise to pluriopotent cells that are highly versatile and can give rise to any cell except the cells in the placenta. At the next stage, cells become multipotent, meaning they can give rise to several other cell types, but those types are limited in number. An example of multipotent cells is hematopoietic cells?blood stem cells that can develop into several types of blood cells, but cannot develop into brain cells. At the end of the long chain of cell divisions that make up the embryo are "terminally differentiated" cells?cells permanently committed to a specific function [Author not known, 2003]."
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Umbilical Cord Stem Cells, 2004.
Examines the ethical and medical issues surrounding the utilizing of stem cells.
5,350 words (approx. 21.4 pages), 18 sources, APA, $ 132.95
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Abstract
Umbilical cord blood offers great hope for the future of stem cell research and use. This paper examines the potential of these types of stem cells in order to demonstrate how stem cells from umbilical cord blood can help scientists solve the ethical debate and provide sick patients with hope for life.
Paper Outline
Introduction
Stem Cell Background
About Umbilical Cord Stem Cells
Umbilical Cord Blood Process
The Great Stem Cell Debate
Conclusion
Works Cited
From the Paper
"Estimations regarding the need for a given cord blood sample vary. One estimate of a child needing his or her own cord blood stem cells is 1:10,000 (Wolf, 2002). Another places the odds at 1:1000 to 1:2000. The probability of use varies depending on individual circumstances. Disturbing statistics reveal that every year there are about 8,000 new cases of cancer in children under the age of 15. These children could potentially benefit from the use of cord blood stem cells, so perhaps expectant parents should make the effort to donate their newborn?s cord blood or store it for their own family?s potential use."
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Epithelial Cells of the Nephron, 2008.
This paper describes the epithelial cells of the nephron, which is the basic structural and functional unit of the kidney.
1,040 words (approx. 4.2 pages), 11 sources, MLA, $ 36.95
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Abstract
This paper explains that the framework of the nephron in the kidney is made up of epithelial cells. The author points out that there are two types of nephrons, cortical and juxtamedullary, and they are named according to the location within the renal parenchyma. The paper relates that epithelial cells that make up the nephron must be able to preserve nutrients and materials required by the body and return them to circulation, while leaving wastes, toxins and excess water to be expelled. The author states that the epithelia are described by the number of layers and the shape of the cells at the edge closest to the exterior environment, thus helping to prevent bacteria and other foreign materials from entering the body. The paper continues that the epithelial cells of the nephron permit the kidney to have particular functions that include controlling blood pressure.
From the Paper
"Epithelium lines the surfaces of the body and is positioned on the borders between the exterior and interior environments. Epithelium is a tissue composed of cells, bound tightly together with no intercellular connective tissue. These cells derive their food and oxygen from the tissue fluid that filters through from the capillaries in the underlying connective tissue. The epithelium develops in the embryo from all the three germ layers; ectoderm, mesoderm and endoderm. The epithelium is derived from mesenchyme cells that mature into connective tissue, bone, cartilage, blood and the lymphatic system."
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Stem Cells, 2002.
An examination of the ethical debate of whether to use stem cells for research.
1,165 words (approx. 4.7 pages), 8 sources, MLA, $ 40.95
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Abstract
This paper gives a brief description of what stem cells are and how they may be used in scientific research. Recent studies show that stem cells may hold the key to discovering a cure for many mysterious diseases, including Parkinson?s and Alzheimer?s. But the moral issues remain intact, despite the obvious positive consequences. The core of the stem cell debate is a battle over abortion, as stem cells come from embryos. This paper discusses both sides of the debate and looks at government intervention.
From the Paper
"For pro-life advocates, the moral costs of the research far outweigh any potential benefits. For scientists, the possibilities of research are awe-inspiring and bewildering. No one denies the moral dilemma of the stem cell debate. But to turn back now, researchers say, would be like turning our backs on a bright, sustaining light because we are terrified of the shadows it creates. "
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