ChemSemBlog

There was a presentation on March 4, 2010 about synthesis, application and commercial development of dendrimer. The presentation was given by Mr. Joseph Heinzelmann who is the product manager of dendritic nanotechnologies, Inc. The presentation was very impressive because it was full of informative contents about business in chemistry as well as scientific contents. He started the seminar introducing the basic knowledge of dendrimers. What properties do dendrimers have? How are they synthesized? What application can they be used?

Mr. Joseph Heinzelmann told us that dendrimers are highly organized polymers which are built from repeating branching sides. As the complexity of the molecules, there are a number of different types. Dendrimer is composed of a core molecules, interior rod, and surface group. The question I asked to him was that which molecules can be a core molecule. He answered that any molecule is able to be a core molecule of a dendrimer and the company he is working for is using ammonia group for the core molecule. One of the applications of the dendrimer is to carry molecule like drugs or imaging agents. Nowadays, the treatment for cancer is MTX which blocks the pathway of synthesizing Tetrahydrofolate from Folate. However, the weak point of MTX is that it is non-selective. It means that MTX also affect on normal body cells which grow rapidly such as hair cell. If dendrimers carry MTX to only tumor cells, they will be the best way to treat cancer.

I would tell my friends that the presentation was a good chance to learn how a company based on chemistry is operated and how dendrimers can be used.

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On February 18, 2010, there was a presentation which was about properties of cellular membrane of the life.  The guest speaker was Mary L. Kraft. The title of the presentation was Visualizing Lipids in Plasma Membrane. She is an assistant professor of the University of Illinois, in Urbana-Champaign. Her presentation was very calm and tranquil. Even though it was not easy for me to understand her presentation thoroughly, it was a good chance to know deeper knowledge of the properties and composition of cellular plasma membrane than I learned in other chemistry and biology classes.

Dr. Mary L. Kraft started her presentation introducing us the basic information of cellular plasma membrane. It is composed of two lipid layers and there are various kinds of lipid in the membrane such as cholesterol, glycans, and transmembrane protein. The selective permeability of the membrane plays an important role as a barrier of the cell.

For direct approach to prove cell membrane organization, Dr. Mary L. Kraft used a high resolution secondary ion mass spectrometry (SIMS) which is new for me. It is used to reveal a map of elemental and isotopic composition. She told us that there are only seven SIMS in U.S.A. Throughout the presentation, I wonder when the instrument was developed and became commercially used and how she was able to conduct the experiments with it.

I would tell my friends that the presentation was about finding out the organization of cell membranes that is mainly composed of various kinds of lipids.

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On January 28, 2010, Basar Bilgicer who is a professor at University of Notre Dame visited Andrews University for his presentation. Mr. Basar Bilgicer prepared two presentations. One of them was “Peptide Design Using Unnatural Amino Acids.” The other was “Multivalent Antibody Aggregation.”  More students in the presentation wanted to know about the antibody aggregation. Therefore, he started the presentation, introducing us the basis of antibody. Especially, he talked about IgG antigen. Overall, he showed us a lot of illustrations which explained how the antibody which has bivalency or trivalency worked with antigens and ligands. Also, he used chromatographic graphs which supported his experimental results. It made me easy to understand how the antibody aggregates in various ways.

There were several kinds of ways which antibody binds to antigen or ligands. Largely, the antigens were divided up depending on the shape, whether they are bivalent, or trivalent. Then, they generated several aggregates, such as dimer, trimer, tetramer, or polymer. They also were produced in a cyclic form, a linear form, or in the middle.

During the presentation, he gave details about the correlation between the Gibbs free energy and the binding constant. I asked him about the effects of temperature on the binding constant. He answered that denaturing occurs above five to ten Celsius degree than the body temperature and the binding constant decreases as the temperature decreases under room temperature.

I would tell my friends that the presentation was about the kind of how and what is involved in binding between antibodies and antigens, or ligands.

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On February fourth, there was a presentation about colon and rectal cancer given by Amanda B. Hummon, who is from University of Notre Dame. Her presentation title was “Functional Interrogation of Genes Driving Colorectal Cancer.” I thought that her presentation was very well organized. Also, she explained basic information about cancer cell without difficult words, which made me understand her presentation much easier.

She started the seminar introducing basic properties of cancer cell to us. The cancer cell is caused by disease on genome which is particular number and combination of certain chromosomes. She also explained about the basic structure of chromosome which contains gene in it. I learned that the white region of a chromosome is gene rich zone, while the black region of the chromosome is gene poor zone. There are several factors which contribute to occurring cancer cells, which are DNA, RNA, Function, pathways and etc.  Dr. Hummon especially focused on the relationship between DNA, RNA and cancer cells.

She collected sample of tumor and mucosa cells from patients to compare them. In the future, she said that she would like to have an experiment how the genes are regulated by mRNA and protein. Throughout the presentation, I wondered how she obtained DNA from tumor cells. I also would like to ask her what causes the change of number or shape of gene or chromosome.

I would tell my friends that the presentation is about the factors which cause cancer in colon or rectum in microscopic views such as DNA, RNA, or protein.

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There was a presentation about lipid natural product by Robert E. Minto at Andrews University. He is a bioorganic chemist at Indiana University. One of the interesting things in his presentation was that he showed us pictures of fungi from which he extracted lipid for his experiment. However, it was hard for me to understand completely his presentation, overall.

He explained about the variety of lipid. It is made up of fatty acids, their derivatives, or substances which are related biosynthetically, or functionally to these compounds. Usually, Lipid is classified into two large categories. One of them is Acetate-derived group which contains   triacylglycerol, or sphingolipid. The other is MEP-derived group which includes cholesterol, or steroid hormone. Also, these groups are divided into countless lipid groups depending on the temperature at which it is synthesized, the number of carbon atom, the number of double bond which a lipid molecule contains and the type of double bond; cis, or trans.

One thing I would like to know is that which condition makes cis double bond and which condition produces trans double bond in a lipid structure. Also, one of the questions which came across my mind during the presentation was that it is possible to use the plant lipid as fuel for instruments or implements which we are using in our daily lives. One day, I read about the possibility of using plant fuel which contaminates less than other fuels such as coal, and petroleum. If it is possible to use the plant lipid as fuel and to synthesize it without contamination of nature in a cheap way, we would be able to save many things on the earth.

I would like to tell my friends that lipid is synthesized in various ways under various conditions.

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On January 14, 2010, there was a presentation about disk implants given by Ryan K. Roeder, who is from University of Notre Dame. His presentation title was “Porous and Bioactive Polyaryletherketone Implants.” It was very interesting that the theme of his seminar is related to the material which is used practically in our daily lives. Overall, his presentation attracted me because he explained the way which his product is used as well as the way which he has developed to synthesize the material with various conditions.

He started the seminar introducing the students to the materials which are commonly used when doctors operate on implants. These are metal, ceramics, and polymers. Each of these materials has their own strength and weakness. Especially, whether the material is injectable and bioresorbable, are two standards for implants. One of the products his research focuses on is Polyaryletherketone. This is a good material for replacing disks located between backbones, because it is biocompatible, and bioinert. In addition, it has higher strength than other materials.

In synthesizing Polyarlyetherketone, Roeder changed many variables to obtain the most suitable material for implant in a human body. In variables, there are porosity, amount of HA, and temperature which the material is synthesized at. In particular, the temperature effects on the sintering and mechanical integrity. At higher temperature which is about 375 Celsius, both sintering and mechanical integrity increase.

I would tell my friends that as we grow older, the materials which help supporting our bodies between the bones that are worn out. Therefore, as the level of medical technology increases, the we can discover materials which are able to replace bone.  Roeder’s work takes us down that path.

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The guest speaker for this week’s Seminar in Chemistry was Jefferey A. Turk. He has worked as a fragrance maker. Now, he is a professor at Alma College, researching about synthesizing molecules which smell like odors of nature. Overall, he spoke clearly and slowly, and explained contents easily.

He started the seminar introducing us to the mechanism of how we smell. He said that, to be a fragrance molecule, it needs to be volatile, less than three hundred grams per mole and hydrophobic. If the molecule is non-volatile and hydrophilic, it would not reach the olfactory receptor and we cannot smell it. He, also, said that stereochemistry is important in producing fragrance. If the molecule has S conformation, it would have different smells from R conformation molecules.

The benefit of manufacturing artificial smells are, that we can save natural resource and make fragrance cheaper than using real natural oil. The price of synthetic compounds is one thousand times cheaper than the price of natural oil. The interesting thing was that the main materials for popular perfume to people are from excrement of animals. For an example, musk is from feces of deer.

Throughout the presentation, I was wondering whether the organic compound has any effects on human body. He also said that there is an organization which is responsible for regulating and supervising the safety of fragrance.

It is very interesting to know about applications of organic chemistry, and behind the story of synthesizing fragrance. I would tell my friends that the seminar was about making various smells, or fragrance, by mixing chemical compounds.

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The guest speaker for chemistry seminar was Jyllian Kemsly. She is an associate editor of Chemical and Engineering News. She earned her doctorate degree in Chemistry at Standford University. While attending doctorate program, she also took the science writing program, which gave her a chance to work as a science writer.

The seminar was held by video conference. Sometimes, when we asked her questions, she answered a little bit later. However, the seminar finished without much trouble. I think that video conference is a good tool to learn and share thoughts between the people whom I can not reach easily and me.

From the seminar, I learned what C&EN consists of, what kind of weekly news there are in the magazine, what makes a good science writer and her life story. Throughout her life story, I could understand writers’ challenges, solicitude and rewards. One interesting thing was that a person needs to have thick skin to be a good science writer. The reason is that everyone has different thoughts, and the writers cannot fit to everyone’s opinion.

She had worked as a freelance for a few years, and joined C&EN. I asked her about the reason why she applied to C&EN. She told me that she had several reasons. One of them was that it was not easy for her to write science things to general audience.

I would tell my friends that the seminar was about science writing skills and if you become a science writer, it involves creativity, flexibility of your time, and intellectual freedom.

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Today’s guest speaker for the chemistry seminar was Hisashi Yamamoto. He is an Arthur Holly Compton Distinguished Service Professor at the University of Chicago. He has received various awards in chemistry and published hundreds of articles, reviews, books, and journals.

The title of the presentation was “Designing Asymmetric Catalysis – Cascade Reaction for Polyketide synthesis.” Mainly, Hisashi Yamamoto explained about synthesizing catalysts, which have more power than other catalysts that have existed before. Generally, a catalyst is a chemical substance which is not consumed in the chemical reaction. However, it participates by speeding up or speeding down the reaction through reducing or increasing the activation energy of the reaction. He said that by using strong catalysts, he can reduce the amount of steps needed to make products, which also saves time, money, and materials. Also, I learned that it is important for cascade reactions to have no side products and load very low catalyst.

From his presentation, I found that most of the reactions he did occurred at very low temperature; from -78°C to 0°C. I was wondering if there were any special reasons that the temperature was very low. Does the temperature affect the behavior of the catalyst?

It was interesting that I had a chance to meet a world famous chemist and learn about his passion for his job. He said that he had never thought about having any other career except as a chemist. I want to be as passionate about my work as he is.

I would tell my friends that he is using more effective chemical substances which help speed up reactions.

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On October 22^nd, there was a presentation about geological science given by Michael A. Velbel, who is from Michigan State University. His presentation title was “Rate and Rate-determining Processes in Natural Weathering of Rock-forming minerals.” It was very interesting that the theme of his seminar had not been presented during past seminars. Also, he used a lot of visual data, like SEM or TEM pictures, which attracted my attention.

The purpose of his research was to examine the weathering rates of minerals in metamorphic bedrock in the southern Appalachian Blue Ridge, specifically in Coweeta watershed. He said that he collected the data once a week and analyzed it to make a model and related molecular distribution ratio. From his seminar, I learned that the reaction formula which the textbook presents does not fit well in real reaction for Na-feldspar weathering. Also, he said that nomenclature for geological compounds is from the name of a place which they are found, or a person who discovers the compound. Lastly, he explained the applications of geologically analyzed data. For example, we might be able to say that there was water on Mars because the marks on the surface of Mars are similar to the water marks on the soil of the Earth.

I would tell my friends that the seminar was about researching which molecules consist of mineral, and which facts affect the forming rates of minerals. This helps us easily understand the mysteries occurring on the Earth and other planets in the Solar system.

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Today’s guest speaker for chemistry seminar was Adam J. Matzger. He is a professor of chemistry at University of Michigan in Ann Arbor, Michigan. He graduated from Oberlin College with a bachelor’s degree.  Also, he earned his doctorate degree at the University of California at Berkeley. While attending graduate school, he investigated theoretical and experimental properties of dehydrobenzoannulenes and phenylenes. Currently, Dr. Matzger is doing research on organic materials in the solid state ranging from crystalline polymorphs to porous materials.

Dr. Matzger presented on how to store hydrogen gas and capture carbon dioxide molecule. At first, he introduced the definition of coordination polymer. It is an assembly of porphyrin building blocks into network structures with large channels. Secondly, he explained about the ways of synthesizing coordination polymers. Lastly, he talked about applications of the products he made. Overall, it was easy to understand the concept of his research for me because he explained it using some examples we can see easily in our daily lives.

During the presentation, he said that he measured the ability of the polymer to capture hydrogen gas or carbon dioxide gas according to the pressure. I was curious about how he increased the pressure during the experiments. In addition, he used carboxylic acid groups to make a polymer structure. I was wondering the effects of using carboxylic acid group and adding more carboxylic acid groups.

Hydrogen gas is a powerful energy source. However, it is dangerous if it is not stored in a proper way. When we can store it safely, we can use it efficiently in our actual lives.

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On October 8^th, there was a presentation about organic synthesis given by Sean Reed. He is a graduate student at the University of Illinois in Urbana-Champaign, Illinois. He graduated from the Iowa State University with a bachelor’s degree in Chemistry and psychology. Currently, Mr. Reed is doing a research with Professor White on intermolecular C-H amination, and the strategic application of C-H activation reactions in complex molecules synthesis.

Mr. Reed’s presentation title was “Recent Advances in Allylic C-H Amination.”  He started the presentation by introducing the class to a general basic process of synthesizing oxidized hydrocarbons, and allylic and aliphatic C-H oxidation product from nature. I learned that we can get oxidized hydrocarbons by using 3 different ways which are functional group transformation, C-C bond formation and olefin oxidation. Also, he talked about catalytic allylic C-H oxidation. Especially, in branched allylic oxidation, he and his research team members are using catalytic cycle, which is not focused on reactant or product, but on catalyst. As it was last week, the speaker did not state his purpose clearly, so I did not get the objective of the presentation even after the presentation was over. I was curious about how we can apply the results of the research in our daily lives. Overall, it was interesting that he spoke about a field that we never explored before in organic chemistry, even though I took sophomore organic chemistry.

I would tell my friends that the presentation was about looking for a more efficient way to synthesize chemical materials.

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Today’s guest speaker for chemistry seminar was Carolyn E. Anderson. She is an assistant professor of chemistry at Calvin College in Grand Rapids, Michigan. She graduated from the University of Michigan with a bachelor’s degree in Chemistry. Also, she earned her doctorate degree in Organic Chemistry at the University of California at Irvine. Currently, Dr. Anderson is doing research on developing new synthetic methods to produce N-alkyl pyridones, as well as amino acid homologues.

Dr. Anderson’s presentation title was “Synthesis of N-Alkyl pyridones: Methodology and Mechanism.” She started the presentation by introducing the class with a new O- to N-alkyl migration strategy for the preparation of N-benzyl and propargylic pyridines. Secondly, she explained about the mechanism of benzyl migration. Lastly, she talked about an unusual product, which she did not expect to produce. Overall, her speaking speed was too fast for me to understand all the things that she explained.

From the presentation, I learned about Hammett Correlation, which correlates electronic effects of a series of substituent to reaction rate. If the p values are negative, the substituent is electron donating group, which increases the reaction rate. However, if the p values are positive, it has an electron withdrawing group.

Throughout the presentation, I was wondering about the theme and objective of  Dr. Anderson’s experiment. Why is she finding a new strategy to synthesize N-Alkyl pyridone? Also, I did not understand the concept of sigma hole. Which factors affect  creating sigma holes?

I found it interesting that N-alkyl pyridones are from nature. Throughout the history, scientists have tried to produce different products to have positive effect on our body system. Those products could heal a disease, or relieve the pain. However, I think that if the products are not nature products, they could cause unwanted side effects on our body. Therefore, the idea of making N-alkyl pyridones from natural products was very intriguing and interesting for me.

Soldiers make various strategies to gain victory. Similarly, scientists make various strategies to get a new product which will lead us to gain victory over various diseases.

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Today’s guest speaker for chemistry seminar was Wendell P. Griffith. He earned a doctor’s degree in Analytical Chemistry at the University of Massachusetts.  Also, he conducted research at John Hopkins University School of Medicine.

His presentation title was “Breathing New Life into Old Protein.”   The main theme was a story of hemoglobin and hemoglobin binding protein. Before presenting about hemoglobin and its binding protein, he explained about Mass Spectrometry, or MS, which is used to analyze and determine the composition of molecules. It is a good instrument for efficient separation and high resolution.  The neutral molecule has to be converted to an ion to be analyzed and for its mass to be determined. After that, he talked about the application of MS to protein structure and dynamics, hemoglobin assembly and dissociation, heptoglobin, and band3.

I also learned that Dalton John is called the  father of atomic theory. He published the first atomic weight table, and did research on colour blindness, which  is also called Daltonism.  In addition, α helix chain of hemoglobin is made from number 16 chromosome, while β sheet chain of it is made from number 11 chromosome of DNA. Therefore, α globin and β globin have different roles in hemoglobin assembly.  α-Globin plays an important role as a rigid template when they are assembled into hemoglobin.  On the other hand, β globin is flexible enough to efficiently form the hemoglobin tetramer.

The presentation was interesting to me because it dealt with biochemistry.  As a biochemistry major, it was a good chance to learn the connection between our body system and chemistry. When we assemble new furniture and use it, we need to read the description to know how each part functions.   Similarly, to use our body better, we need to study, analyze and understand more knowledge about our body.  So, this seminar allowed me to understand more about hemoglobin.

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Today’s guest speaker was Silas Cook who is one of the faculty members in the Chemistry Department of Indiana University.

His presentation title was “The Evolution of a Synthesis: 11-o-Debenzoyltashironin. This compound affects on TRK receptor and is used to treat Alzheimer’s disease.

At first, he told us the difference between total synthesis and methodology in synthetic organic chemistry, which I did not know before. Total synthesis focuses on natural products, structure determination, biological activity and pharmaceuticals. In methodology, scientists study new conditions and their effects on existing reactions and also synthesis of new products using same reagents. Therefore, number of steps, yield, control/selectivity, purification and cost are important things to consider in methodology. He used both ways, which give him new strategies and fundamental understanding.

Cook also spoke about and introduced us to some other drugs. of interest to him. For example, Artemisinin is used for treating malaria. He said that  it is cheap in  the U.S. but not in the Third World, where it is needed most. In addition, Maoecrystal V and Englerin A are used to treat cancer.

He mainly explained about the steps to synthesize 11-o-Debenzoyltashironin. I was impressed when I heard that the compound was made in 12 steps and in the steps, there were some reactions which I learned in Organic Chemistry class. Moreover, it is interesting that a new compound, made by synthetic organic chemistry, gives hope to people who have a tough time because of a chronic disease. I would tell my friends that we can make useful compounds which are able to treat fatal diseases by using various organic reactions.

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Matthew Allen is an assistant professor of Wayne State University in Detroit, MI.  After graduating from Swartz Creek High School, MI, he earned his bachelor degree in chemistry and a minor in mathematics at Purdue University, West Lafayette, IN. Also, he obtained a doctorate in Chemistry at California Institute of Technology.

Allen obtained several distinguished awards from NIH, NSF, Eli, Lilly and Bausch & Lomb. Currently, he is conducting research that involves inorganic chemistry, organic synthesis, analytical chemistry and biology.  His presentation on September, 10, 2009 at Andrews University was about Magnetic Resonance Imaging, which is abbreviated MRI.

The presentation was interesting. The main idea, MRI, was related to improvement of our practical lives and I could learn more about MRI. Through the presentation I learned about the properties and uses of lanthanide, which we do not study about in our regular chemistry classes and labs. Also, I learned that water, the applied magnetic field, and chemical environment affect the functioning and effectiveness of MRI.

There were few things that I did not understand. One of them is the meaning of relaxivity. Even though he explained and defined the meaning of the relaxivity, he spoke kind of fast, so I could not catch the concept of the relaxivity in a short time.

Students attending seminar asked Allen a lot of questions. He kindly answered most of the questions. However, there were some questions that he could not answer because the research is still going on.

I liken chemical environment and MRI to a camera and a lens. In order to get clear pictures, we use a camera with a better lens which has better resolution. Like this, to get better pictures of inside of our body, scientists try to develop a better chemical environment, that is, ‘lens’ for MRI.

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