Transesterification kinetics of soybean oil 1

Transesterification of soybean oil (SBO) and other triglycerides with alcohols, in the presence of a catalyst, yields fatty esters and glycerol. Di- and monoglycerides are intermediates. Reactions are consecutive and reversible. Rate constants have been determined for each reaction with a computerized kinetic program. The effects of the type of alcohol, 1-butanol or methanol (MeOH); molar ratio of alcohol to SBO; type and amount of catalyst; and reaction temperature on rate constants and kinetic order were examined. Forward reactions appear to be pseudo-first order or second order depending upon conditions used. Reverse reactions appear to be second order. At a molar ratio of MeOH/SBO of 6:1, a shunt reaction was observed. Energy of activation was determined for all forward and reverse reactions under a variety of experimental conditions from plots of log k vs 1/T. Values ranged from 8–20 kcal/mol. 1Presented at the AOCS meeting in Philadelphia, PA, May, 1985. 2 Deceased.     

Benefit Without Cost in a Mechanics Laboratory

This paper describes, in some detail, a very simple “building block” experiment designed to motivate students towards the mastery of the basic principles of stability, dimensional similarity and the interpretation of practical measurements. The experiment consumes very little of either money, space, or time and can easily be adapted to challenge students of widely different abilities.     

Newborn Country USA

"Newborn Country USA" describes a concept for a regionwide, integrated perinatal care system that serves a population of more than four million. How the four sectors of the Denver Regional Perinatal Center - The Children's Hospital, Denver, Denver General Hospital, Fitzsimons Army Medical Center, and the University of Colorado Army Medical Center - interact as a regional resource, relate to 223 hospitals in portions of 10 states, and assist in serving a portion of 70,000 live births in 1976 are reported.     

Selective hydrogenation with copper catalysts: II. Kinetics

To explain the unusually high selectivity of copper catalysts toward linolenate, model compounds were hydrogenated (150 C and atmospheric pressure) and the reaction products analyzed. Products varied depending upon location of the double bonds. Monoenes were not reduced by copper chromite except when the double bond was next to a carboxyl group. Dienes with isolated double bonds also were not reduced. Binary mixtures of model compounds were hydrogenated with copper chromite. From the composition of the initial and final products, a competitive rate ratio of the two compounds was determined. Esters with conjugated double bonds reacted faster than esters containing methylene interrupted double bonds. Kinetic data on the hydrogenation of linolenate indicated conjugation of the double bonds. Simulation of the kinetic data gave competitive reaction rates for the different isomers formed. Presented at the AOCS Meeting, New York, October 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

On-line chemical database for new crop seeds

Since the 1950s, a database of the chemical composition of seeds, collected throughout the world, has been generated at the National Center for Agricultural Utilization Research. Information contained in the database is primarily selected chemical and physical properties of seed oils. Over more than 38 years, 15,738 accessions of 7,924 species of 2,339 genera from 225 families were collected and analyzed. This database is now accessible on the Internet at http://www.ncaur.usda.gov/nc/ncdb/search.html.ssi. This paper gives an overview of the database, describes the information available, and illustrates how to do searches. Retired USDA/ARS.     

Lectin-affinity chromatography brain glycoproteomics and Alzheimer disease: insights into protein alterations consistent with the pathology and progression of this dementing disorder

Alzheimer disease (AD) is a neurodegenerative disorder characterized pathologically by the accumulation of senile plaques and neurofibrillary tangles, and both these pathological hallmarks of AD are extensively modified by glycosylation. Mounting evidence shows that alterations in glycosylation patterns influence the pathogenesis and progression of AD, but the vast number of glycan motifs and potential glycosylation sites of glycoproteins has made the field of glycobiology difficult. However, the advent of glycoproteomics has produced major strides in glycoprotein identification and glycosylation site mapping. The use of lectins, proteins that have strong affinity for specific carbohydrate epitopes, to enrich glycoprotein fractions coupled with modern MS, have yielded techniques to elucidate the glycoproteome in AD. Proteomic studies have identified brain proteins in AD and arguably the earliest form of AD, mild cognitive impairment, with altered affinity for Concanavalin-A and wheat germ agglutinin lectins that are consistent with the pathology and progression of this disorder. This is a relatively nascent field of proteomics research in brain, so future studies of lectin-based brain protein separations may lead to additional insights into AD pathogenesis and progression.     

The Role of Sulfur Dioxide in the Regulation of Mitochondrion-Related Cardiomyocyte Apoptosis in Rats with Isopropylarterenol-Induced Myocardial Injury

The authors investigated the regulatory effects of sulfur dioxide (SO₂) on myocardial injury induced by isopropylarterenol (ISO) hydrochloride and its mechanisms. Wistar rats were divided into four groups: control group, ISO group, ISO plus SO₂ group, and SO₂ only group. Cardiac function was measured and cardiomyocyte apoptosis was detected. Bcl-2, bax and cytochrome c (cytc) expressions, and caspase-9 and caspase-3 activities in the left ventricular tissues were examined in the rats. The opening status of myocardial mitochondrial permeability transition pore (MPTP) and membrane potential were analyzed. The results showed that ISO-treated rats developed heart dysfunction and cardiac injury. Furthermore, cardiomyocyte apoptosis in the left ventricular tissues was augmented, left ventricular tissue bcl-2 expression was down-regulated, bax expression was up-regulated, mitochondrial membrane potential was significantly reduced, MPTP opened, cytc release from mitochondrion into cytoplasm was significantly increased, and both caspase-9 and caspase-3 activities were increased. Administration of an SO₂ donor, however, markedly improved heart function and relieved myocardial injury of the ISO-treated rats; it lessened cardiomyocyte apoptosis, up-regulated myocardial bcl-2, down-regulated bax expression, stimulated mitochondrial membrane potential, closed MPTP, and reduced cytc release as well as caspase-9 and caspase-3 activities in the left ventricular tissue. Hence, SO₂ attenuated myocardial injury in association with the inhibition of apoptosis in myocardial tissues, and the bcl-2/cytc/caspase-9/caspase-3 pathway was possibly involved in this process.     

Competitive hydrogenation rates of isomeric methyl octadecadienoates

Determination of the relative reaction rates of isomeric methyl octadecadienoates is possible by competitive reduction of a mixture containing an inactive diene and a radioactively labeled isomer. The hydrogenation rate of methylcis-9,cis-12-octadecadienoate with platinum and nickel catalysts is compared to the hydrogenation rate of each of several isomers of methyl octadecadienoate, and the relative rate of the competitive hydrogenations is calculated by a digital computer. Methylcis-9,cis-12 linoleate is reduced the most rapidly of all the dienes studied. The relative rates of the positional isomers tend to decrease with the increasing number of methylene groups between the double bonds, except when one of the double bonds is in the more reactive 15 position. Comparison of the geometric isomers shows thattrans,trans diene is hydrogenated at a slower rate thancis,cis linoleate.