Effect of sodium diclofenac loads on mesophase components and structure

We studied the effect of a model electrolytic drug on intermolecular interactions, conformational changes, and phase transitions in structured discontinuous cubic QL lyotropic liquid crystals. These changes were due to competition with hydration of the lipid headgroups. Structural changes of the phase induced by solubilization loads of sodium diclofenac (Na-DFC) were investigated by directly observing the water, ethanol, and Na-DFC components of the resulting phases using 2H and 23Na NMR. Na-DFC interacted with the surfactant glycerol monoolein (GMO) at the interface while interfering with the mesophase curvature and also competed with hydration of the surfactant headgroups. Increasing quantities of solubilized Na-DFC promoted phase transitions from cubic phase (discontinuous (QL) and bicontinuous (Q)) into lamellar structures and subsequently into a disordered lamellar phase. Quadrupolar coupling of deuterated ethanol by 2H NMR showed that it is located near the headgroups of the lipid and apparently is hydrogen bonded to the GMO headgroups. A phase transition between two lamellar phases (L alpha to L alpha*) was seen by 23Na NMR of Na-DFC at a concentration where the characteristics of the drug change from kosmotropic to chaotropic. These findings show that loads of solubilized drug may affect the structure of its vehicle and, as a result, its transport across skin-blood barriers. The structural changes of the mesophase may also aid controlled drug delivery.     

Quality assurance for molecular epidemiology of tuberculosis methods in the mycobacterium reference laboratory

In the National Mycobacterium Reference Laboratory of the Israeli National Public Health Laboratory (hereafter referred to as “the laboratory”), three methods are employed for the molecular epidemiology of Mycobacterium tuberculosis: IS6110 restriction fragment length polymorphism typing (RFLP typing), 43 spacer oligonucleotide typing (spoligotyping), and 24 loci Mycobacterial Interspersed Repeating Unit—Variable Number of Tandem Repeats typing (MIRU-VNTR typing). In this article, we describe the main practical aspects concerning quality assurance of these methods that are based on standardized, internationally agreed upon conditions, including consensus reference strains and markers. All three methods were validated by classical epidemiology (confirmed transmission) and clinical information. The laboratory has introduced a new 5 colors, 4 primer sets multiplex modification of the optimal 24-miru typing system that includes an easily produced in-house internal standard for the high-throughput capillary electrophoresis system. Quantitative measurement of the internal standards yielded statistics for measurement uncertainty that include the frequency distribution, mean, standard deviation, 95% confidence interval and coefficient of variation. Use of the new internal standard developed in our laboratory allowed us to introduce the first quantitative evaluation of the system performance of the AB3130xl capillary electrophoresis genetic analyzer for MIRU-VNTR typing. The results are discussed in terms of expected accuracy and precision of MIRU-VNTR results, and possible implications for forensic microsatellite typing which may be much more sensitive to the observed intra- and inter-plate variation.     

Symmetry breaking in an initially curved micro beam loaded by a distributed electrostatic force

The asymmetric buckling of a shallow initially curved stress-free micro beam subjected to distributed nonlinear deflection-dependent electrostatic force is studied. In order to highlight the symmetry breaking phenomenon and the approach to its analysis, the subsidiary simplified problem of a curved beam attached to a linearly elastic foundation, and subjected to uniformly distributed “mechanical” load, which is independent of deflections, is addressed first. The analysis is based on a two degrees of freedom reduced order (RO) model resulting from the Galerkin decomposition with linear undamped eigenmodes of a straight beam used as the base functions. Simple approximate expressions are derived defining the geometric parameters of beams for which an asymmetric response bifurcates from the symmetric one. The necessary criterion establishes the conditions for the appearance of bifurcation points on the unstable branch of the symmetric limit point buckling curve; the sufficient criterion assures a realistic asymmetric buckling bifurcating from the stable branches of the curve. It is shown that while the symmetry breaking conditions are affected by the nonlinearity of the electrostatic force, its influence is less pronounced than in the case of the symmetric snap-through criterion. A comparison between the RO model results and those obtained by direct numerical analysis shows good agreement between the two and indicates that the obtained criteria can be used to predict non-symmetric buckling in electrostatically actuated bistable micro beams.     

BRCA1/2 mutation carriers: living with susceptibility

OBJECTIVES: To examine whether being a BRCA1/2 mutation carrier affects a wide array of aspects of life, and if so, how. METHODS: Participants were grouped according to their carrier status (carrier and noncarrier status), health status (affected or unaffected by cancer), and their enrollment at the counseling service (probands and other family members). One hundred and sixty-five women completed a self-administered questionnaire following their genetic consultation session. RESULTS: Probands/nonprobands and carriers/noncarriers did not differ with regard to demographic characteristics, health behaviors including medical checkups, the distress they experience or their resources (sense of coherence, social integration, religiosity). Individuals affected by cancer did differ on some of these aspects from participants without cancer. CONCLUSIONS: From the results of this study, being a carrier could not be considered a psychosocial risk factor, nor does it seem to have an effect on carriers' resources and lifestyle.     

Compatible valuations and generalized Milnor -theory

Given a field and a subgroup of there is a minimal group for which there exists an -compatible valuation whose units are contained in . Assuming that has finite index in and contains for prime, we describe in computable -theoretic terms.

     

Computing homotopic shortest paths efficiently

We give deterministic and randomized algorithms to find shortest paths homotopic to a given collection Π of disjoint paths that wind amongst n point obstacles in the plane. Our deterministic algorithm runs in time , and the randomized algorithm runs in expected time O(k_out+k_inlogn+n(logn)^1+ε). Here k_in is the number of edges in all the paths of Π, and k_out is the number of edges in the output paths.     

Spectral deformations of automorphic functions over graphs of groups

Supported by the Alfred P. Sloan and the National Science Foundations     

A spray-based method for the production of semiconductor nanocrystals

We present a spray based-method for the formation and production of semiconductor nanocrystals that provides an attractive alternative to the commonly used epitaxial and colloidal procedures. According to this spray-based method, mainly thermospray, solutions of semiconductor salts are first sprayed into monodispersed droplets, which subsequently become solid nanocrystals by solvent evaporation. A semiconductor nanocrystal is produced from a single spray droplet upon the full vaporization of the solvent. The average diameter and size distribution of the final nanocrystals are controlled and determined by the solute concentration of the sprayed solution and by the droplet size, hence by the spray production parameters. The spray-produced nanocrystals are collected on any selected solid support. Representative results, shown in this letter, reveal the formation of CdS nanocrystals in the size range of 3 to 6 nanometers and with a size distribution of as low as five percent. A further structural analysis of these nanocrystals showed that they were formed in the zinc blend phase with a high degree of crystallinity.     

Determination of magnesium in blood serum using a flow-injection system with a potential-scanning electrochemical detector equipped with a thin-film deaerator

Batch and flow-injection determination of magnesium in blood serum, based on the adsorptive reduction current peak of the Eriochrome Black T—magnesium complex, is described. A potential-scanning electrochemical detector, equipped with a novel thin-film deaerator, allows the successful adaptation of the batch method to a flow-injection system. Using a simple flow system, up to 35 samples h^?1 can be processed. The results obtained agree well with those obtained by atomic absorption spectrometry.