MECHANISTIC ASPECTS OF CAROTENOID BIOSYNTHESIS

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemical Reviews, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/cr400106

Synthesis and characterisation of some metal complexes of hybrid phosphorus-nitrogenligands: the crystal structure of 1-(diphenylphosphino)-2-(2-pyridyl)ethane cobalt(II) chloride

Some iron(II), cobalt(II) and copper(II) complexes of the hybrid ligand 1-(diphenylphosphino)-2-(2-pyridyl)ethane (dppe) and diphenyl-2-pyridylphosphine (dppp) have been synthesised and characterised. Analyses suggest tetrahedral structures in which the metal atoms are bonded to two chlorine atoms and to both phosphorus and nitrogen atoms for 1-(diphenylphosphino)-2-(2-pyridyl)ethane on one hand and on the other hand, bonding is through the nitrogen atoms of two molecules of diphenyl-2-pyridylphosphine, which acts as a monodentate ligand. The crystal structure of 1-(diphenylphosphino)-2-(2-pyridyl)ethane cobalt(II) chloride shows a pseudo-tetrahedral structure in which the aminophosphine is bonded to the cobalt centre through both the phosphorus and nitrogen atoms, forming a 6-membered ring. KEY WORDS: Aminophosphines, Metal complexes, Cobalt(II) complex, Crystal structure  Bull. Chem. Soc. Ethiop. 2008, 22(2), 253-260

Calibration of an HPGe detector and self-attenuation correction for Pb-210: Verification by alpha spectrometry of Po-210 in environmental samples

In this work the calibration of an HPGe detector for Pb-210 measurement is realised by a liquid standard source and the determination of this radionuclide in solid environmental samples by gamma spectrometry takes into account a correction factor for self-attenuation of its 46.5 keV line. Experimental, theoretical and Monte Carlo investigations are undertaken to evaluate self-attenuation for cylindrical sample geometry. To validate this correction factor (at equilibrium with Po-210 Pb-210) alpha spectrometry procedure using microwave acid digestion under pressure is developed and proposed. The different self-attenuation correction methods are in coherence, and corrected Pb-210 activities are in good agreement with the results of Po-210. Finally, self-attenuation corrections are proposed for environmental solid samples whose density ranges between 0.8 and 1.4 g/cm(3) and whose mass attenuation coefficient is around 0.4 cm(2)/g. (C) 2007 Elsevier B.V. All rights reserved

Optically-Switched Resonant Tunneling Diodes for Space-Based Optical Communication Applications

We are developing a new type of digital photo-receiver that has the potential to perform high speed optical-to-electronic conversion with a factor of 10 reduction in component count and power dissipation. In this paper, we describe the room-temperature photo-induced switching of this InP-based device which consists of an InGaAs/AlAs resonant tunneling diode integrated with an InGaAs absorber layer. When illuminated at an irradiance of greater than 5 Wcm(exp -2) using 1.3 micromillimeter radiation, the resonant tunneling diode switches from a high-conductance to a low-conductance electrical state and exhibits a voltage swing of up to 800 mV

Cloud Condensation Nuclei properties of model and atmospheric HULIS

Humic like substances (HULIS) have been identified as a major fraction of the organic component of atmospheric aerosols. These large multifunctional compounds of both primary and secondary sources are surface active and water soluble. Hence, it is expected that they could affect activation of organic aerosols into cloud droplets. We have compared the activation of aerosols containing atmospheric HULIS extracted from fresh, aged and pollution particles to activation of size fractionated fulvic acid from an aquatic source (Suwannee River Fulvic Acid), and correlated it to the estimated molecular weight and measured surface tension. A correlation was found between CCN-activation diameter of SRFA fractions and number average molecular weight of the fraction. The lower molecular weight fractions activated at lower critical diameters, which is explained by the greater number of solute species in the droplet with decreasing molecular weight. The three aerosol-extracted HULIS samples activated at lower diameters than any of the size-fractionated or bulk SRFA. The Köhler model was found to account for activation diameters, provided that accurate physico-chemical parameters are known

Toward a Structure Determination Method for Biomineral-Associated Protein Using Combined Solid- State NMR and Computational Structure Prediction

SummaryProtein-biomineral interactions are paramount to materials production in biology, including the mineral phase of hard tissue. Unfortunately, the structure of biomineral-associated proteins cannot be determined by X-ray crystallography or solution nuclear magnetic resonance (NMR). Here we report a method for determining the structure of biomineral-associated proteins. The method combines solid-state NMR (ssNMR) and ssNMR-biased computational structure prediction. In addition, the algorithm is able to identify lattice geometries most compatible with ssNMR constraints, representing a quantitative, novel method for investigating crystal-face binding specificity. We use this method to determine most of the structure of human salivary statherin interacting with the mineral phase of tooth enamel. Computation and experiment converge on an ensemble of related structures and identify preferential binding at three crystal surfaces. The work represents a significant advance toward determining structure of biomineral-adsorbed protein using experimentally biased structure prediction. This method is generally applicable to proteins that can be chemically synthesized

Data Management Guide: Integrated Baseline System (IBS). Version 2.1

The Integrated Baseline System (IBS) is an emergency management planning and analysis tool that is being developed under the direction of the US Army Nuclear and Chemical Agency (USANCA). The IBS Data Management Guide provides the background, as well as the operations and procedures needed to generate and maintain a site-specific map database. Data and system managers use this guide to manage the data files and database that support the administrative, user-environment, database management, and operational capabilities of the IBS. This document provides a description of the data files and structures necessary for running the IBS software and using the site map database

Evolution from 4f-electron antiferromagnetic to ferromagnetic order in the CeCu(Ge1-xSnx) alloy series (0≤x≤1)

We report the evolution from ferromagnetic (FM) to antiferromagnetic (AFM) state in CeCu(Ge1-xSnx) investigated by means of magnetic and heat capacity measurements. X-ray diffraction studies for all compositions indicate the ZrBeSi - type hexagonal crystal structure with space group P63/mmc (No. 194). The magnetic susceptibility, x(T) at high temperature follows the Curie - Weiss relation with an effective magnetic moment close to the value of 2.54 µB expected for free Ce3+ - ion. At low temperatures, x(T) data indicate AFM transition for alloys in the concentration range 0.7≤x≤1 and FM for x≤0.6. The magnetization, M(µ0H) of samples exhibiting AFM behaviour shows metamagnetic transition at low magnetic fields with some irreversibility in the process of increasing and decreasing magnetic field. In turn, M(µ0H) of samples exhibiting FM behaviour shows saturation in high magnetic fields. Heat capacity, Cp(T) data confirm the AFM and FM transitions observed in magnetic measurements. An additional anomaly below TC and TN is observed in Cp(T)/T, which likely arises from spin reorientation or rearrangement in FM or AFM structure. Below in FM region, Cp(T) can be well described assuming spin-waves excitations with an energy gap ∆C.Scopu

Anxiety sensitivity and medication nonadherence in patients with uncontrolled hypertension

Objective Anxiety sensitivity—fear of the negative social, physical, or cognitive consequences of anxiety related sensations—has been linked to cardiovascular disease and adverse cardiovascular health behaviors. Medication nonadherence may account for this association. We examined whether anxiety sensitivity was independently associated with objectively measured medication nonadherence in a multi-ethnic primary care sample. Methods Eighty-eight patients with uncontrolled hypertension completed the Anxiety Sensitivity Index and had their adherence to blood pressure (BP) medications measured during the interval between two primary care visits using an electronic pillbox (MedSignals®). Multivariable Poisson regressions were conducted to determine the relative risks of medication nonadherence associated with anxiety sensitivity after adjustment for age, gender, Hispanic/Latino ethnicity, education, total number of prescribed medications, and depressive and posttraumatic stress disorder (PTSD) symptoms. Results Nearly twice as many patients with high anxiety sensitivity were nonadherent to BP medications compared to patients with low anxiety sensitivity (65.0% vs. 36.8%; p = 0.03). Patients with high anxiety sensitivity had higher relative risks of medication nonadherence than their low anxiety sensitivity counterparts (adjusted relative risk [RR] = 1.76; 95% CI: 1.03–3.03). Conclusions In this first study of the association between anxiety sensitivity and medication adherence, we found that high anxiety sensitivity was strongly associated with BP medication nonadherence, even after adjustment for known confounders. Our results suggest that teaching patients who have uncontrolled hypertension adaptive strategies to manage their anxiety sensitivity may help improve their medication adherence, and thereby lower their cardiovascular risk