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Thursday February 9th Thursday March 16th Thursday April 18th Abstracts for this Spring's talks Thursday February 9th Plants as a Source of Drugs Abstract: It is remarkable to what a large extent medicinal treatment for
many centuries rested on the use of plants. Plants have given the field of
medicine many useful drugs; such pharmacological phootypes as digitalis, cinchona,
ergot, and opium, to mention a few. Humankind's first investigation of the
plant kingdom was prompted by a dependence on plants as a source of food.
From varied observations of the effects of plants on themselves, human use
of plants arrow and weapon poisons, as hallucinogens, and medicaments slowly
evolved. In the early days witch doctors, apothecaries, and physicians used
plants to treat disease, elevate mood, and relieve pain. As the art of chemistry
evolved, humans learned to isolate the pure chemicals that caused the medicinal
effect and to use them. Opium yielded codeine and morphine to relieve pain,
and Digitalis provided digitoxin for the heart. Ergot made available ergonovine
and ergotamine for migraine and childbirth and, paradoxically, the synthetic
LSD as a hallucinogen. The presence of sucha wide and diversified group of
compounds has prompted the search of plants for new narcotics, heart drugs,
and psychoactive and anticancer compounds. Although many drugs are produced
synthetically, natural products have served as the molecular model for their
starting point. Today, some 40% all prescriptions include compounds of natural
origin. Many diseases still cannot be effectively treated with current therapy.
How does one find effective agents for these diseases? Plants contain many
more compounds than chemists can synthesize. The more than 250,000 uninvestigated
higher plant species on the face of the Earth are a source of potential new
and effective drugs. However, in the face of the destruction of the Amazon
rain forest, time grows short. Thursday March 16th Glass: Its Many Facets Abstract: Glass is a material that is as old as civilization and yet as modern
as fiber optics. We use a great variety of glass products both in our everyday
lives and in the field of chemistry. But for most of us the nature and chemistry
of glass tend to remain obscure. Using a historic approach, this talk will
focus on the basic chemistry of glass and the methods used to form it into
useful objects. A half dozen major glass families will be examined, and their
unique and useful properties will be related to their chemical composition
and treatment. Several demonstrations will be used to show some of the special
properties of glass. The presentation will touch on some of the interesting
and Thursday April 18th The Application of Chemistry to the Examination
of a Work of Art Abstract: Scientists have been associated with museum conservation laboratories
for many years. Only recently, however, have art curators and conservation
begun to appreciate the contributions that scientists can make in the preservation
and restoration of the art objects. At present, about a dozen museums in the
United States have conservation science departments. Art conservation frequently
requires specific information about the component materials of a painting
or object prior to treatment. Due to the complex stratification of paintings,
most questions that arise concern the nature of their components. Microscopic
cross sections of a painting are frequently taken and viewed with the polarizing
microscope to understand the different layers that make upthe object. Pigment
identification is frequently employed to determine if the pigments are in
keeping with the time period of the object, as well as to understand the artist's
materials and methods. Such tasks are performed using polarized light microscopy
and X-ray diffraction of powdered samples or X-ray fluorescence, which is
well-suited to this talk due to it's noninvasive nature. To study the identity
of binding media, the conservation scientist uses gas chromatography (GC),
high-performance liquid chromatography (HPLC), and infrared spectroscopy.
GC is used to identify oil-containing binders, as well as for the identification
of waxes and various low molecular weight resins, HPLC can be used to identify
proteinaceous binders and organic dyes. Ultraviolet radiation can be used
to examine the varnish layer of a painting as well as to identify areas retouched
in previous conservation treatments. Infrared reflectography is frequently
used to examine underdrawing on a painting. In addition, X-rays are often
used to determine where lead white has been used on a painting, as well as
to reveal damaged areas beneath the painting's surface. This talk will focus
on the application of these various techniques to the examination of paintings
and sculpture. Examples will be presented from the National Gallery of Art
collection. September 13, 2004 ACS Meeting.
Chemagination -- An
exciting essay and poster competition for high school chemistry
students; Essay writing starts as
early as September, 2005, Final Competition will be on April 21, 2006 at Lawrence
University in Appleton.
Prize, Fun, and Educational
Submit a Job Opportunity for Posting
National Chemistry Week, January 2004
Submit Volunteer Opportunities for Posting
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