N-bromosuccinimide in the conjugation of fatty acids and oils

1. A series of methyl esters of fatty acids were reacted with N-bromosuccinimide, and the products were dehydrobrominated by heating.
2. In the reaction of metyyl erucate and methyl oleate with equivalent amounts of N-bromosuccinimide, bromination occurred in the allylic position farthest from the carboxyl group. Products of dehydrobromination contained 30–40% conjugated dienoic acids.
3. Use of excess N-bromosuccinimide led to production of both diene and triene conjugation.
4. Products from mono-acetylenic fatty acids had a double bond conjugated to the triple bond initially present.
5. The product from methyl 9∶12-linoleate was a complex mixture having diene, triene, and tetraene conjugation.
6. Mustard seed, peanut, olive, karanja, neem, tobacco seed, and safflower oils were reacted with N-bromosuccinimide. The bromo derivatives could not be satisfactorily dehydrobrominated by heat alone; heating in pyridine, quinoline, or 2∶4∶6-collidine was more effective. The products from safflower and tobacco seed oils partially gelled during the process. The films of all the treated oils dried in wrinkled patterns.

     

Geographic and sociodemographic variation in self-reported seat belt use in the United States

Background

With new data available, we sought to update existing literature on the prevalence of self-reported seat belt use by state, region, and rural/urban status and to estimate the strength of the association between seat belt use and rural/urban status adjusted for type of seat belt law and several other factors.

Methods

We examined data on self-reported use of seat belts from 50 states, the District of Columbia, and three territories using the 2008 Behavioral Risk Factor Surveillance System, a state-based random-digit-dialed telephone survey (n = 406,552). Reported seat belt use was assessed by state, U.S. Census regions, and U.S. Department of Agriculture (USDA) rural/urban continuum codes.

Results

Overall, 85% of adults in the United States reported they always used seat belts. Regionally, the West had the highest prevalence of persons who reported that they always wear seat belts (89.6%) and the Midwest had the lowest (80.4%). States with primary seat belt laws had the highest prevalence of reported seat belt use, compared with states with secondary or no laws. After adjusting for various sociodemographic characteristics, body mass index, and type of seat belt law, persons in the most densely populated metropolitan areas were significantly more likely to report always wearing seat belts than those in most sparsely populated rural areas (adjusted odds ratio = 2.9).

Conclusion

Our findings reinforce the evidence that primary enforcement seat belt laws are effective for increasing seat belt use, and suggest that upgrading to primary enforcement laws will be an important strategy for reducing crash-related fatalities in rural areas.     

Densities,Viscosities, Sound Speeds,Refractive Indices,and Excess Properties of Binary Mixtures of Isoamyl Alcohol with Some Alkoxyethanols

Densities and viscosities were measured for binary mixtures of isoamyl alcohol with 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol over the entire range of composition at 303.15 K, 313.15 K, and 323.15K and ultrasonic speeds and refractive indices at 303.15 K under atmospheric pressure. From the experimental values of density, viscosity, ultrasonic speed, and refractive index, the values of excess molar volume (V ^E), viscosity deviations (Δη), deviations in isentropic compressibility (ΔK _S ), and excess molar refraction (ΔR) have been calculated. The excess or deviation properties were found to be either negative or positive, depending on the molecular interactions and the nature of liquid mixtures.     

Thermodynamics of the Frustrated 2D Hubbard Model

The thermodynamic properties of the quarter filled 2D Hubbard model extended by next-nearest-neighbor (NNN) hopping have been studied in an exact diagonalization method on a tilted square cluster. The NNN hopping interaction (i.e. frustration) is prominent at the low-temperature region. A positive (negative) diagonal hopping t′ favors (suppresses) double occupancy and hence decreases (increases) local moment. At higher temperatures thermal excitations favor the formation of doublans against the strong Coulomb repulsion U and the weak diagonal hopping, hence decreasing local moment. A two-peak structure is observed in the specific heat curves with the inclusion of negative NNN hopping. The low-T peak in specific heat is highly suppressed in comparison to the high-T peak. It has also been argued that t′ influences the ‘pseudogap’ energy scale. In the present case of quarter filling, a weak and short range antiferromagnetic order is present at very low temperatures, which is slightly suppressed (enhanced) by positive (negative) t′. The effect of t′ is more pronounced in the non-interacting limit.     

Diversity Analysis,Batch Fermentation and Characterization of Nisin in Identified Strains of Lactococcus lactis spp. lactis

Thirty-one strains of Lactococcus lactis spp. lactis were identified out of 89 isolates of lactic acid bacteria (LAB) from dairy and nondairy sources. Of the 31 strains, 24 (46.1%) were obtained from dairy and seven (18.9%) from non-dairy sources. The cluster analysis of rep-PCR showed that (GTG)₅-PCR followed by ERIC-PCR exhibited more discriminating potential than BOX-PCR. The obtained banding patterns characterized the polymorphism among strains. The strain level polymorphism was also obtained by the combined cluster analysis of (GTG)_5, ERIC and BOX-PCR which exhibited a level of heterogeneity among strains but not with the sources of isolation. Among 31 strains, 17 strains were able to produce zones of inhibition against Lactobacillus acidophilus NCDC 015 and therefore considered as nisin producers. Nisin production by strains was further confirmed by PCR amplification of nisA/Z of 174 bp size. The nisin activity and cell growth observed to be higher in pH controlled batch fermentation than in uncontrolled fermentation. The nisin activity, cell concentration, and acidity were high in immobilized cell system than free cell batch fermentation. The hot acid and chloroform extraction method was found to be the efficient way for the partial purification of nisin from fermented broth.     

Protein-based indicator system for detection of temperature differences in high pressure high temperature processing

Since the kinetics of change of target attributes in high pressure high temperature (HPHT) processing are not only pressure but also clearly temperature dependent, a control of temperature in space and time is indispensible. A tool that can easily detect temperature differences in prototype HPHT vessels during a HPHT process would aid the design of industrial HPHT equipments. In this work, the potential of ovomucoid as extrinsic, isolated, protein-based indicator to detect temperature differences inside a HPHT vessel was assessed. Ovomucoid fulfilled the selection criteria of a candidate indicator for HPHT. Solvent engineering was successfully used to shift the inactivation window of the candidate indicator into the HPHT processing window. Since, the dissociation equilibrium of buffer systems shifts under high pressure and/or under high temperature, a critical evaluation of the effect of a pH-shift of the selected phosphate buffer system in the context of protein-based indicator development was performed. The ovomucoid system inactivation kinetics were characterized under isobaric–isothermal conditions and modeled best by a first order inactivation model. A temperature dependent inactivation at constant pressure could be observed, which creates potential for the detection of temperature differences under HPHT conditions. These integrating properties were unaffected under dynamic, industrially relevant HPHT conditions.     

Determination of the stress level for voltage screen of integrated circuits

Voltage screen is a method to screen out products that suffer from defectivity related issues. A risk associated with voltage screen is that the applied voltage is too severe and damages the product. Most papers dealing with voltage screen determine the stress voltage by a general rule of thumb (focusing on one specific mechanism) without taking into account the particularities and the knowledge of the specific process.This paper describes a general approach to determine a safe level for voltage screening of products. In this approach, the onset of the wearout phase is not allowed to shift more than 1%. All the information needed to determine the voltage value is in general typically available from the process reliability tests performed as part of the process qualification.     

Integral transform approach for solving dynamic thermal vibrations in the elliptical disk

The present article is concerned with the determination of thermally induced transverse vibration of a uniform thin elliptical disk with elastic supports at both radial boundaries. The temperature field on the disk is considered to be a ramp-type prescribed on the top face while the bottom face is kept at zero temperature. In this study, integral transform technique is used to investigate the conductivity equation in an exact manner by the use of Mathieu functions and modified Mathieu functions. The thermal moment is derived on the basis of temperature distribution, and its stresses are derived based on the resultant bending moments per unit width. The numerical calculations of the distributions of the transient temperature and its associated thermoelastic results are performed, and the numerical results are shown in the figures.     

A SYSTEMATIC APPROACH FOR INVESTIGATION OF SPRAY DRYING PROCESSES

Abstract

A systematic approach is developed for investigation of spray drying processes for chemical and biological systems. The approach involves an in-depth study of atomizer performance, spray dryer parametric sensitivity, spray-dried powder properties, thermal inactivation and post-drying properties. The approach helps considerably in rational design of spray drying experiments and in investigation and optimization of various process aspects of spray drying of chemical and biological systems, leading to large savings in labor, cost and time.     

Polybenzoxazine‐based composites as high‐performance materials

Polybenzoxazines are newly developed thermoset polymers exhibiting versatility in a wide range of applications including in the electronics and aerospace industries. When combined as composites, the attractive characteristics of both components are apparent. The chemistry of benzoxazine synthesis offers wide molecular design flexibility and thus facilitates preparation of various polybenzoxazine‐based composites. This article reviews recent developments in the preparation and thermal curing of benzoxazine composites with a focus on structure–property relations of cured materials. Copyright © 2010 Society of Chemical Industry