Carboxy-substituted 2-azetidinones as cholesterol absorption inhibitors

Ferric ions bind to citrate and undergo an autoreduction to form a ferrous-citrate complex, greatly increasing the redox activity of the iron complex. Ferrous ions and citrate are also essential for the enzymic activity of aconitase. Aconitase, with its iron-sulphur cluster has a versatile structure which allows it to act as an iron regulatory protein (IRP-1). The purpose of this study was to see whether iron binding, and its autoreduction by citrate, could play a physiological signalling role in iron regulation. Significant amounts of ferrous ions were associated with citrate, when measured using ferrozine, however, these did not appear to activate iron-requiring aconitase.     

Piezoelectricity and carrier dynamics in In0·2Ga0·8As/GaAs single quantum wells grown on (n11)A-oriented GaAs (n=1, 2, 3)

Temporal variations of the photoluminescence (PL) peak wavelength due to screening of the piezoelectric field by photogenerated carriers are observed in ln_0·2Ga_0·8As/GaAs single quantum wells grown on (n11)A-oriented substrates (n=1, 2, 3) by using time-resolved PL spectroscopy. The partial screening of the piezoelectric field shifts the PL peak to shorter wavelengths. The subsequent decrease of the photogenerated carriers by recombination produces a redshift of the PL peak, which is explained using a model that fits successfully the experimental results.     

Escalated substance use: A longitudinal grouping analysis from early to middle adolescence.

The authors surveyed a cohort of 1,184 adolescents in the 7th, 8th, and 9th grades. Measures of tobacco, alcohol, and marijuana use and of constructs from 3 theoretical models of substance use were obtained at each point. Clustering analysis for 3-wave substance use data indicated subgroups of nonusers, minimal experimenters, late starters, and escalators. Discriminant function analyses tested whether study variables differentiated the subgroups. One discriminant function accounted for the majority of between-group association; it had loadings for (high) life stress, nonadaptive coping, deviance-prone attitudes, and parental and peer substance use, and (low) parental support, academic competence, and behavioral control. Escalators were high on this function; late starters and experimenters had intermediate values; and nonusers were low on the function. Implications for theories of vulnerability to substance abuse are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical Basis for Evaluating the Reliability of p?n Junction Devices

The measurement and prediction of the reliability of semiconductor devices is becoming increasingly more dependent upon an understanding of device physics. The present level of understanding tanding of device physics is, however, inadequate for many practical purposes. This paper reviews the present status of p-n junction theory, its relevance to device degradation, and the experimental techniques available for measuring intrinsic device properties. Limitations in the theory and additional development required to meet the needs of device reliability evaluation and prediction are considered. The role of modeling in evaluating device reliability is discussed.     

Role of Cytokines in Vitiligo: Pathogenesis and Possible Targets for Old and New Treatments

Vitiligo is a chronic autoimmune dermatosis of which the pathogenesis remains scarcely known. A wide variety of clinical studies have been proposed to investigate the immune mediators which have shown the most recurrency. However, such trials have produced controversial results. The aim of this review is to summarize the main factors involved in the pathogenesis of vitiligo, the latest findings regarding the cytokines involved and to evaluate the treatments based on the use of biological drugs in order to stop disease progression and achieve repigmentation. According to the results, the most recurrent studies dealt with inhibitors of IFN-gamma and TNF-alpha. It is possible that, given the great deal of cytokines involved in the lesion formation process of vitiligo, other biologics could be developed in the future to be used as adjuvants and/or to entirely replace the treatments that have proven to be unsatisfactory so far.     

Optical properties of self-assembled InAs quantum dots grown on GaAs(211)A substrate

We have investigated the photoluminescence (PL) and growth properties of self-assembled InAs/GaAs quantum dots (QD) grown on (211)A-oriented GaAs substrate in a low coverage region. At the onset of the QD formation in the Stranski–Krastanov mode, structures of QD on (211)A substrate were quite different from those on (100) substrate. The uniformity of size distribution was better and the density was higher than that grown on (100) substrate. We found a PL peak at 1.32 eV when the InAs coverage was 1.57 ML. Another PL peak gradually appeared at 1.37–1.42 eV with increasing InAs coverage. The peaks at 1.32 and 1.37–1.42 eV were attributed to the emission from a defect-related QD and a typical QD, respectively. When the InAs coverage exceeded 1.89 ML, the QD density decreased with increasing InAs coverage, due to the coalescence of QD. The samples studied here showed PL spectra having a larger intensity and narrower full width at half-maximum compared with that grown on (100) substrate.     

Stainless steel slot antenna with integrated solar cells

A new principle of a solar slot antenna is presented. The slot antenna integrates amorphous silicon solar cells which are directly grown on the ground plane where the slot antenna is cut. To facilitate the deposition of the solar cells, stainless steel was used for the ground plane. The effect on the efficiency of the antenna of this rather unusual choice for the conducting ground plane is also described     

Synuclein Analysis in Adult Xenopus laevis

The α-, β- and γ-synucleins are small soluble proteins expressed in the nervous system of mammals and evolutionary conserved in vertebrates. After being discovered in the cartilaginous fish Torpedo californica, synucleins have been sequenced in all vertebrates, showing differences in the number of genes and splicing isoforms in different taxa. Although α-, β- and γ-synucleins share high homology in the N-terminal sequence, suggesting their evolution from a common ancestor, the three isoforms also differ in molecular characteristics, expression levels and tissue distribution. Moreover, their functions have yet to be fully understood. Great scientific interest on synucleins mainly derives from the involvement of α-synuclein in human neurodegenerative diseases, collectively named synucleinopathies, which involve the accumulation of amyloidogenic α-synuclein inclusions in neurons and glia cells. Studies on synucleinopathies can take advantage of the development of new vertebrate models other than mammals. Moreover, synuclein expression in non-mammalian vertebrates contribute to clarify the physiological role of these proteins in the evolutionary perspective. In this paper, gene expression levels of α-, β- and γ-synucleins have been analysed in the main organs of adult Xenopus laevis by qRT-PCR. Moreover, recombinant α-, β- and γ-synucleins were produced to test the specificity of commercial antibodies against α-synuclein used in Western blot and immunohistochemistry. Finally, the secondary structure of Xenopus synucleins was evaluated by circular dichroism analysis. Results indicate Xenopus as a good model for studying synucleinopathies, and provide a useful background for future studies on synuclein functions and their evolution in vertebrates.     

A patterned and passivated organic-inorganic semiconductorheterojunction diode

A new process for photolithographically patterning and passivating organic-inorganic semiconductor heterojunction devices is described. It makes it possible to overcome two important barriers to the use of organic semiconductors in active optoelectronic integrated circuit applications. The organic semiconductor used was 2,4,9,10-peryelenetetracarboxylic dianhydride (PTCDA), which was vacuum deposited onto the surface of a p-Si substrate. Passivation was achieved via the deposition of SiO₂ onto the organic thin film using a low-temperature process. It was found that the organic-inorganic heterointerfaces is not damaged in the fabrication process, which uses several wet chemical etchants. In addition, all processes employed are compatible with both Si, III-V, and II-VI semiconductor device fabrication technologies. Preliminary reliability tests made at elevated temperatures indicate that the organic-inorganic heterojunction, after passivation is stable over extended periods of time