The October 2006 issue of JYI is highlighting the University of Connecticut's (UCONN's) REU program in Chemistry by publishing the following articles
You're jogging at the gym,exhausted, panting, and sweaty, burning off that dry salad you ate for lunch and wondering how far away the nearest McDonald's is. It seems no matter how hard you work or how little you eat, those extra pounds just won't budge. "Isn't there just a shot they can give me to make me thin?" you wonder.
At one time, it seemed like invisibility was a notion of science fiction, purely based on imagination, but today it seems we may be close to making that fantasy a reality. Scientists have identified a way to make an invisibility cloak (yes, just like the one in Harry Potter) which could render its wearer invisible. This cloak would use a revolutionary material and could literally change the way we see the world.
Polylactide can be processed into fibers and films for various biomedical applications, including sutures, dialysis media, and drug delivery devices. In this work, well-defined biodegradable polylactide (PLA) containing block copolymers, poly(ethylene-co-1,2-butylene)-b-poly(D-lactide) (PEB-b-PDLA) and poly(ethylene oxide)-b-poly(L-lactide) (PEO-b-PLLA), were synthesized via ring-opening polymerization of D- and L-lactides initiated from PEB-OH and PEO-OH macroinitiators, respectively. The goal of this research was to obtain stereocomplexes from PLA block copolymers containing highly immiscible blocks such as hydrophilic PEO and hydrophobic PEB.
We have recently defined a concise, three-step synthesis to carbohydrate-based oxepines from pyranose lactols, where the key step involved a Schrock catalyst mediated ring closing metathesis (RCM) reaction. A sub-family of diene substrates could be cyclized using the Grubbs second-generation catalyst, although the yields were low (25-30%) and a side product, tri-O-benzyl glucal was observed (~10%). The present study was undertaken to find a cleaner and more efficient route of synthesizing oxepines.
The study of fatigue is of major engineering importance because cracks occur more frequently than expected. The goal of this research is to be able to better predict fatigue crack growth (FCG) in 2324 Aluminum Alloy. Being able to accurately determine FCG will help prevent disastrous failure of engineering structures. Through the experimentation of a varying stress intensity factor with a constant stress ratio and constant amplitude loading, a better understanding of FCG is anticipated. Due to time constraints, only the stress ratio of 0.1 was tested for this paper. However, the resulting data from the test was compared with previous data obtained from the exact same test setup, and it was found to be comparable.
The bioconjugation of a protein with an N-hydroxysuccinimide ester is a protein modification technique used to create biomedical and biotechnological products. Some of the difficulties in this type of protein modification reaction are that proteins have many amines which react with N-hydroxysuccinimide esters, and the reaction solutions are difficult to analyze due to the complexity of the components. This study tests on a small scale whether controlling the pH could potentially be used to improve the site specificity of a protein modification reaction.
De novo designed peptide nanoparticles can have the size of a virus and carry antigenic information on their surface. Through genetic engineering, it is possible to mount almost any peptide-based epitope on the surface of the nanoparticles. In theory, the nanoparticles can elicit an immune response when used as a vaccine. Burkhard et. al. have designed such a peptide nanoparticle that consists of 60 peptide monomers and which has a diameter of about 20 nm. Our goal was to develop a novel Human Immunodeficiency Virus (HIV) vaccine by mounting HIV epitopes on the surface of the nanoparticles. In this project, the forward and reverse strands of DNA oligomers that coded for a highly conserved portion of the HIV protein gp41 were annealed. The annealed oligomers were successfully ligated into the expression vector pP_3a that coded for the peptide monomer of the core particle. The recombinant DNA was transformed into the Escherichia coli strain BL21(DE3)pLysS and the bacteria were cloned.
Obesity has been linked to the pathogenesis of heart failure. Leptin, a 16-kD peptide hormone synthesized mainly by the adipocytes reduces food consumption and enhances energy expenditure. Leptin receptors (Ob-R) consist of six isoforms (ObRa-ObRf) and are present mainly in the hypothalamus as well as other tissues. Leptin deficiency and resistance have been implicated in the development of left ventricular hypertrophy and myocardial infarction. Impaired leptin action can also affect insulin sensitivity in cardiomyocytes leading to development of heart failure. The effects of leptin on cardiomyocytes have not been analysed in a comprehensive manner. This review explores how leptin-induced signaling pathways and leptin deficiency or resistance can promote heart failure by promoting cardiomyocyte hypertrophy, maladaptive vascularremodeling, impairing cardiac contractility, and perturbing fatty acid metabolism in cardiac myocytes.