The role of phenols in catalysis of nitrosamine formation

Phenolic compounds which can potentially form C-nitroso derivatives by reaction with nitrite can act as catalysts on the formation of an N-nitrosamine from nitrite and a secondary amine. Using a gas chromatographic technique, this effect has been measured for di- and trihydric phenols and for a number of naturally occurring phenolic compounds in the case of N-nitrosodiethylamine (NDEA) formation. The kinetics for this catalytic effect have been studied in detail with dinitrosoresorcinol and two possible mechanisms have been suggested. In addition, it has been shown that a number of naturally occurring phenols catalyse the formation of NDEA under alkaline conditions and such catalysis can lead to the artifactual formation of nitrosamines during their analysis.     

Structural changes during crystallization of apatite and wollastonite in the eutectic glass of Ca3(PO4)2‐CaSiO3 system

In this study, a bioactive glass of eutectic composition based on Ca₃(PO₄)₂‐CaSiO₃ system was prepared and investigated. It was found that by controlling the nucleation and growth of crystals, a glass‐ceramics free from cracks, containing one or two crystalline phases, and of controlled nano‐ to microscale microstructure can be obtained. Heat treatment of the parent glass produces various calcium phosphates (Ca‐deficient apatite and α‐tricalcium phosphate) and calcium silicates (pseudo‐wollastonite and/or wollastonite‐2M) plus amorphous phases. By combining a number of experimental techniques like ³¹P and ²⁹Si magic angle spinning nuclear magnetic resonance spectroscopy, scanning and transmission electron microscopy, energy‐dispersive X‐ray spectrometry, and Rietveld analysis of X‐ray diffraction patterns, a crystallization model was derived, capable of explaining the observed structural and microstructural changes. The determination of amorphous or crystalline phases enabled to produce time‐temperature‐transformation plots. The structural role on the behavior of these materials and its impact on their in vitro bioactivity are also discussed.     

A comparison of group treatments of women sexually abused as children.

We randomly assigned 65 women who had been sexually abused by a father, stepfather, or other close relative to 1 of 3 treatment conditions: a 10-week interpersonal transaction (IT) group, a 10-week process group, or a wait list condition. Subjects were evaluated at pretreatment, posttreatment, and (if assigned to a group) a 6-month follow-up on measures of social adjustment, depression, fearfulness, and general distress. Results suggested that both the IT and process group formats were more effective than the wait list condition in reducing depression and in alleviating distress; changes were maintained at follow-up. Subjects in the process group format exhibited improvement in social adjustment, whereas subjects in the wait list condition actually deteriorated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multivariate statistical monitoring of process operating performance

Process computers routinely collect hundreds to thousands of pieces of data from a multitude of plant sensors every few seconds. This has caused a “data overload” and due to the lack of appropriate analyses very little is currently being done to utilize this wealth of information. Operating personnel typically use only a few variables to monitor the plant's performance. However, multivariate statistical methods such as PLS (Partial Least Squares or Projection to Latent Structures) and PCA (Principal Component Analysis) are capable of compressing the information down into low dimensional spaces which retain most of the information. Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes. This procedure is demonstrated using simulations of two processes, a fluidized bed reactor and an extractive distillation column.     

Interoperability Test Methodology for ISO 18000-7 Active RFID

Standards are developed by highly reputed organizations with a genuine intention that the document acts as a reference requirement and specification record for all manufacturers, and in this process the consumer is presented with a list of conforming products that are all interoperable. Active RFID tags and readers are designed with commercial intent by different manufacturers according to the ISO 18000-7 standard. Through intensive research and tests, it has come to our attention that it is possible to design two active RFID systems that in their entirety conform to the ISO 18000-7 standard and yet be not interoperable with each other. From this statement it can be inferred that conformance is not the sufficient condition for interoperability as is popularly believed, but only the necessary or minimum condition to satisfy interoperability. Therefore apart from preliminary conformance testing, it becomes absolutely essential to include additional and supplemental interoperability tests into the verification process of the production cycle. This research primarily establishes the requirement for interoperability testing giving instances where the standard fails to insure interoperable products. The traditional method to test interoperability currently in practice are investigated and their limitations are exposed. Further this research paper introduces an innovative and ingenious methodology to test active RFID systems for interoperability at the physical layer.     

Study of oil soluble polymers as drag reducers

This investigation was undertaken to find the most effective material which would reduce the friction coefficient in turbulent flow when added in small quantities to oil pipelines. For this purpose, a series of oil-soluble polymers, namely homopolymers and copolymers of alkyl methacrylates, alkyl acrylates, and alkyl styrenes were synthesized. Emulsion polymerization techniques were used. Commercially available alkyl methacrylate and alkyl acrylate monomers were used in the synthesis. Monomeric alkyl styrenes were synthesized and structures established prior to polymerization. Intrinsic viscosities were measured and viscosity average molecular weights were calculated for several of the homopolymers synthesized in this study. Reduction of factional drag and resistance to shear degradation were measured by pumping a solution of the polymer in a hydrocarbon solvent through a pipe and recording the pressure drop across the pipe. Drag-reducing properties of several of the polymers were correlated in terms of their viscosity average molecular weights. Drag reduction of poly (isodecyl methacrylate) was studied in various hydrocarbon solvents. Drag-reducing behavior of polymers prepared in this study exhibited a strong dependence on molecular weight; increasing the molecular weight increased the drag reduction for a given polymer concentration and pipe size. Several of these polymers were found to be superior to commercially available polyisobutylene as drag reducers, especially in terms of shear stability.     

The effect of predeformation on the creep and stress rupture of an oxide dispersion strengthened mechanical alloy

The effect of higher strain rate predeformation on creep behavior and stress rupture life of the oxide dispersion strengthened nickel-base alloy MA 754 was studied. Both the predeformation and creep testing were conducted at 760 °C. It was found that the minimum creep rate decreased as the amount of prestrain increased and was a factor of two lower at 1.2 pct prestrain. Predeformation also shortened the duration of primary creep. Transmission electron microscopy revealed dislocations being emitted from particle-matrix interfaces after prestraining and an increase in dislocation density with increasing prestrain. These observations are discussed with respect to the mechanical results. Formerly a Graduate Student at Columbia University     

Application of the transportation model to a large-scale “Districting” problem

The “Application of the Transportation Model to a Large-Scale ‘Districting’ Problem” describes a method of partitioning an area containing many geographical locations, each with an associated activity or workload, into districts called “tours.” The objective is to assign each location to a tour in such a way that the total workload assigned to each tour falls within specified limits and that the total cost to service the locations from a specified set of tour “centers” is minimized. The present approach is compared and contrasted with other approaches to the problem in several contexts. The actual situation motivating the present work and the derivation of the transportation linear programming model is described. Special attention is given to features which aid implementation and which more realistically model the actual situation by handling the user's implicit constraints, i.e. those not explicitly contained in the transportation formulation. Finally, the results of an actual large-scale problem are presented.     

FREE CONVECTION EXPERIMENTS OF ATMOSPHERIC AIR IN VERTICAL OPEN ANNULI

Experiments were conducted for free convection of atomospheric air in open annuli (annulus ratios of 1.155, 1.33, 1.63 and 12.0) with an isoflux inner wall and an adiabatic outer wall for surface temperatures up to 856 K. The experiments established that Rayleigh number increased as the film temperature of air increased, reaching a maximum at approximately 375 K, regardless of the annulus ratio. Beyond this temperature, the Rayleigh number decreased as the film temperature increased. For film temperatures of air less than about 375 K, the Nusselt number increased proportionally to the Rayleigh number raised to the one-fourth power. For higher film temperatures, however, the Nusselt number was inversely proportional to the Rayleigh number.     

Variations in systemic and pulmonary endothelin-1 in horses with recurrent airway obstruction (heaves)

Recurrent airway obstruction (RAO) is an asthma-like condition of the horse that represents a major cause of morbidity and loss of performance. The exact pathogenesis of asthma in man is unclear but the role of endothelin (ET) is currently under investigation, thus sparking interest in the bronchoconstrictive and vasoconstrictive properties of endothelin in the equine-specific disease entity. In this study, we investigated the levels of ET-1 in systemic blood, as well as in bronchoalveolar lavage (BAL) from horses with RAO. We also studied how these values might correlate with those of lung function tests and pulmonary artery pressure. Five horses with RAO were evaluated both in remission and in crisis and compared to five control horses. RAO horses had significantly (P<0.05) higher systemic ET-1 levels than control horses. They also had a negative arteriovenous ET-1 difference that may correspond to a net uptake of ET-1 in the lung. RAO horses in crisis had increased amounts of immunoreactive ET in BAL fluid compared to normal control subjects. Additionally, the reduction in lung function seen in RAO horses in crisis was significantly correlated with lower epithelial lining fluid ET-1 levels. Our results demonstrate that endothelin may contribute to the pathogenesis of asthma.