A paper analyzing the physical and chemical properties of the lead (II) and lead (IV) halide compounds. Comparisons between compounds and applications are also discussed.
Abstract After a brief historical introduction to lead compounds, it explains what +2 and +4 cations are and examines their uses. The physical and chemical properties of the lead (II) halides are also discussed, with mention of "mixed" halides (e.g., PbFCl).
Outline
An Introduction to Lead
General Lead Dihalide Trends
Mixed Lead Halides
Lead Chloride
Lead Bromide Lead Iodide
Lead Fluoride
Lead Tetrahalides
Lead Tetrafluoride
Lead Tetrachloride
Possible Lead Halide Application
From the Paper "Lead, located at the bottom of group IVA on the periodic table is well known for being a massive (atomic mass is 207.2 amu) and dense element. The density characteristics associated with lead arise from its rather compact structure despite its large size. This occurs in accordance to the periodic trend that atom size decreases as one moves left to right across a period. This trend, in conjunction with the massive properties found among the period six elements, accounts for the elements ranging from osmium to lead in that row being the densest (osmium does have the largest density) known to exist."
Abstract This paper details the results of a chemistry experiment on the deblocking of benzyloxycarbonlyglycylglycine to glycylglycine. The production of glycylglycine 4, a peptide consisting of two glycine units, is described. The reaction of Z-Gly-Gly-OH 1, an N-carbobenzoxylated peptide was reacted with hydrogen bromide in acetic acid to produce glycylglycine 4. The purification of glycylglycine 4 was achieved through filtration to give a low yield of 13%. The experiment was successful with the product being identified as glycylglycine 4; it was identified as such through the analysis of its melting point.
From the Paper "Z-Gly-Gly-OH 1 is a peptide composed of two gylcine residues or units. Z-Gly-Gly-OH 1 may also be referred to as a C-terminal amino acid because it has a free carboxyl group at the right end of the molecule1. Z-Gly-Gly-OH 1 is reacted with hydrogen bromide in glacial acetic acid, which results in the scission of the N-acyl substituent yielding glycylglycine 42. "
Abstract This paper begins by giving a scientific content breakdown of cadmium, explaining what it looks like and what its uses are. It discusses where the risks exist where one could get cadmium poisoning and what areas are exposed to such an agent. It also looks at toxicological concerns which are the health problems which could occur when exposed to cadmium over a long period of time. It concludes with suggestions for exposure control.
OUTLINE
Introduction
Cadmium poisoning on the Increase
Description of Cadmium
General Concerns about Toxicity
Exposures
Underground Mineral
Water
Airborne
Food
Industrial
Toxicological Concerns
Renal Dysfunction
Immunosuppressant Problems
Emphysema
Anemia
Role in Cancer, Hypertension and Heart and Kidney Disease.
Exposure Control
Safe Levels
Exposure Reduction
From the Paper "Cadmium poisoning was chosen as a topic because it is a threat that can be avoided and because it is not a well-known source of poisoning. Better knowledge of the issue would help reduce incidence. Cadmium, the name for which was derived from the Greek kadmeia, is a zinc ore that resembles tin. It is a metallic blueish white element with the atomic number 48 and the atomic weight of 112.40. Cadmium has many uses in industry. At one time, Cadmium was included in medications, but these have since been replaced by less toxic drugs. A recurrent problem is cadmium poisoning, brought about through the inhalation of cadmium in fumes created by welding, smelting, or other industrial processes involving solder. Cadmium bromide is used in engraving, lithography, and photography and can cause severe gastrointestinal symptoms if swallowed. Cadmium poisoning may also be caused by the ingestion of acidic foods prepared and stored in cadmium-lined containers, such as lemonade in certain metal cans."
Abstract This paper discusses California medflies and explains how these pest have not only posed a problem for Californian growers since the 1960s, but also pose a threat to international trade through exported produce. The author describes the possible threats to the environment and human health if spraying as a way of eradication of the medflies is undertaken. In return, the paper suggests several methods in which the stake holders can consider in the control of medflies.
Outline:
The Medfly Problem: General Overview
Facts about the Case
The Decision Makers
Goals and Main Concerns of the Decision Makers
Possible Alternatives and Likely Responses
Cold-storing the Produce to Kill the Medfly
Spraying with Malathion via the Air
Spraying with Methyl bromide and Ethylene dibromide
Comprehensive Plan: Fumigation and Cold Storage Prior to Shipping to out-of-state
Doing Nothing and Hoping the Problem Corrects Itself Over Time
Viable Solutions from the above Evaluations
Possible Future Monitoring
Work Cited
From the Paper "How to combat the problem posed by the medfly to agriculture and international trade? While the California agricultural industry looks eagerly towards the expanding Asian market as a potential and continuing source of revenue, it must also combat the spread of the medfly, a pest that has dogged the industry since the 1960s and feared by the Japanese government. Japan fears that the medfly could enter its borders through imported California produce. To contain the medfly California growers first imposed quarantines on medfly-infested areas, and when the medfly threat reasserted itself in the 1990s, the agricultural industry then resorted spraying affected areas with pesticides."
Tags: pests agriculture, international trade, produce
