PEO coatings obtained on an Mg-Mn type alloy under unipolar and bipolar modes in silicate-containing electrolytes

Protective surface layers with high corrosion resistance (R_p = 3.3·105 ohm cm²) and significant microhardness (H = 4.8 GPa), as compared to the substrate material, were obtained on MA8 magnesium alloy by bipolar Plasma Electrolytic Oxidation (PEO) in a silicate-fluoride electrolyte. The phase and elemental composition and morphology of the coatings were investigated. It was found that the application of the bipolar PEO mode enables one to synthesise on the alloy's surface a high-temperature phase of magnesium silicate, forsterite (Mg₂SiO₄) having good anticorrosion and mechanical properties.     

The nuclear factor-kappa B RelA transcription factor is constitutively activated in human pancreatic adenocarcinoma cells

To assess the efficiency of nasally administered cartilage-specific collagens as vaccination against development of arthritis and to ameliorate already established chronic arthritis, experimental models which develop chronic arthritis, pristane-induced arthritis (PIA), and homologous collagen-induced arthritis (CIA) in the rat were selected. Cartilage-specific collagens type IX (CIX) and type II (CII) were used for vaccination intranasally. A single dose of 250 microg CII instilled intranasally in rats with established PIA ameliorated the disease. For the prevention of disease, the same dose given before immunization was found to be most effective. Most importantly, the disease was more severe if this dose was given three times. For treatment of PIA, CIX was found to be more effective than CII, whereas for treatment of CIA only CII was effective. The amelioration of CIA was associated with a marked suppression of delayed type hypersensitivity and the flare reaction to CII and lower levels of IgG2b anti-CII antibodies in serum, i.e., with suppression of the TH1 rather than the TH2 response to CII. These findings, that cartilage proteins, if given intranasally, can both prevent and ameliorate established chronic arthritis in rats, are of significant importance for possible use in rheumatoid arthritis. The identification of two different cartilage-specific proteins (CII and CIX) effective against a disease induced with a well-defined nonimmunogenic adjuvant such as pristane will be of value for enhancing the effectiveness of the treatment.     

Effects of hostility on ambulatory blood pressure and mood during daily living in healthy adults.

This study (a) tested the effects of hostile attributes on ambulatory blood pressure (BP), heart rate, and mood monitored repeatedly over 3 days in 100 healthy men and women and (b) determined whether the cardiovascular effects of trait hostility were moderated by mood. Multilevel random-coefficients regression analyses showed that hostile individuals exhibited higher systolic and diastolic BP and rated their current moods as more negative and less positive throughout the monitoring. Individuals low in hostility exhibited high BP only during the few occasions when they experienced negative mood. However, these patterns were true only when participants were classified by Potential for Hostility ratings from the Structured Interview (R. H. Rosenman, 1978), not by the Cynical Hostile Attitudes score derived from the Cook-Medley scale. Results provide convergent and ecological validity of interview rating of hostility and illuminate one possible dynamic mechanism by which overt hostile behaviors might contribute to the rates of increased cardiovascular morbidity and mortality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Light-dependent changes in outer segment free-Ca2+ concentration in salamander cone photoreceptors

Simultaneous measurements of photocurrent and outer segment Ca2+ were made from isolated salamander cone photoreceptors. While recording the photocurrent from the inner segment, which was drawn into a suction pipette, a laser spot confocal technique was employed to evoke fluorescence from the outer segment of a cone loaded with the Ca2+ indicator fluo-3. When a dark-adapted cone was exposed to the intense illumination of the laser, the circulating current was completely suppressed and fluo-3 fluorescence rapidly declined. In the more numerous red-sensitive cones this light-induced decay in fluo-3 fluorescence was best fitted as the sum of two decaying exponentials with time constants of 43 +/- 2.4 and 640 +/- 55 ms (mean +/- SEM, n = 25) and unequal amplitudes: the faster component was 1.7-fold larger than the slower. In blue-sensitive cones, the decay in fluorescence was slower, with time constants of 140 +/- 30 and 1,400 +/- 300 ms, and nearly equal amplitudes. Calibration of fluo-3 fluorescence in situ from red-sensitive cones allowed the calculation of the free-Ca2+ concentration, yielding values of 410 +/- 37 nM in the dark-adapted outer segment and 5.5 +/- 2.4 nM after saturating illumination (mean +/- SEM, n = 8). Photopigment bleaching by the laser resulted in a considerable reduction in light sensitivity and a maintained decrease in outer segment Ca2+ concentration. When the photopigment was regenerated by applying exogenous 11-cis-retinal, both the light sensitivity and fluo-3 fluorescence recovered rapidly to near dark-adapted levels. Regeneration of the photopigment allowed repeated measurements of fluo-3 fluorescence to be made from a single red-sensitive cone during adaptation to steady light over a range of intensities. These measurements demonstrated that the outer segment Ca2+ concentration declines in a graded manner during adaptation to background light, varying linearly with the magnitude of the circulating current.     

Folding mechanism of the alpha-subunit of tryptophan synthase, an alpha/beta barrel protein: global analysis highlights the interconversion of multiple native, intermediate, and unfolded forms through parallel channels

A variety of techniques have been used to investigate the urea-induced kinetic folding mechanism of the alpha-subunit of tryptophan synthase from Escherichia coli. A distinctive property of this 29 kDa alpha/beta barrel protein is the presence of two stable equilibrium intermediates, populated at approximately 3 and 5 M urea. The refolding process displays multiple kinetic phases whose lifetimes span the submillisecond to greater than 100 s time scale; unfolding studies yield two relaxation times on the order of 10-100 s. In an effort to understand the populations and structural properties of both the stable and transient intermediates, stopped-flow, manual-mixing, and equilibrium circular dichroism data were globally fit to various kinetic models. Refolding and unfolding experiments from various initial urea concentrations as well as forward and reverse double-jump experiments were critical for model discrimination. The simplest kinetic model that is consistent with all of the available data involves four slowly interconverting unfolded forms that collapse within 5 ms to a marginally stable intermediate with significant secondary structure. This early intermediate is an off-pathway species that must unfold to populate a set of four on-pathway intermediates that correspond to the 3 M urea equilibrium intermediate. Reequilibrations among these conformers act as rate-limiting steps in folding for a majority of the population. A fraction of the native conformation appears in less than 1 s at 25 degrees C, demonstrating that even large proteins can rapidly traverse a complex energy surface.     

Small signal frequency response studies for plasma electrolytic oxidation

Plasma assisted electrochemical treatments provide new possibilities in surface modification of various materials including light weight alloys. However, their large-scale application is still restricted, mainly due to poor understanding of the process mechanisms and consequent limitations in process control and automation. This problem can be resolved if the frequency response (FR) of the system is known and applied for process diagnostics. Our previous work has shown the effectiveness of the large signal mode for FR studies of plasma electrolytic oxidation (PEO) of aluminium. This research is dedicated to FR measurements during PEO of Al in the small signal mode corresponding to small perturbations of voltage signal around large DC values. The study was carried out during PEO of Al at DC voltages which were varied from 450 to 600 V. The FR obtained is a frequency dependent admittance of the PEO electrolyser; this complex number is represented by a modulus and a phase angle. Under potentiostatic conditions, the modulus evolution strongly correlates with the average current value; therefore, it bears insufficient amounts of independent information. The FR phase angle measured within this study was never obtained before. Depending on the frequency, it varies between 0° and 70 ° in the capacitive domain. One of the most notable features of this characteristic is low values at 500-5000 Hz when microdischarges appear during PEO. The other feature is a correlation with the coating growth. As a result, a new diagnostic tool was developed and shown to be effective for evaluation of microdischarges and surface properties during the treatment, thus decreasing the uncertainty in the system.     

Synthesis, biochemical evaluation, and classical and three-dimensional quantitative structure-activity relationship studies of 7-substituted-1,2,3,4-tetrahydroisoquinolines and their relative affinities toward phenylethanolamine N-methyltransferase and the alpha2-adrenoceptor

7-Substituted-1,2,3,4-tetrahydroisoquinolines (7-substituted-THIQs) are potent inhibitors of phenylethanolamine N-methyltransferase (PNMT, EC 2.1.1.28), the enzyme involved in the biosynthesis of epinephrine. Unfortunately, most of these compounds also exhibit strong affinity for the alpha2-adrenoceptor. To design a selective (PNMT vs alpha2-adrenoceptor affinity) inhibitor of PNMT, the steric and electrostatic factors responsible for PNMT inhibitory activity and alpha2-adrenoceptor affinity were investigated by evaluating a number of 7-substituted-THIQs. A classical quantitative structure-activity relationship (QSAR) study resulted in a three-parameter equation for PNMT (PNMT pKi = 0.599pi - 0.0725MR + 1. 55sigmam + 5.80; n = 27, r = 0.885, s = 0.573) and a three-parameter equation for the alpha2-adrenoceptor (alpha2 pKi = 0.599pi - 0. 0542MR - 0.951sigmam + 6.45; n = 27, r = 0.917, s = 0.397). These equations indicated that steric effects and lipophilicity play a similar role at either active site but that electronic effects play opposite roles at either active site. Two binding orientations for the THIQs were postulated such that lipophilic and hydrophilic 7-substituents would not occupy the same region of space at either binding site. Using these two binding orientations, based on the lipophilicity of the 7-substituent, comparative molecular field analysis (CoMFA) models were developed that showed that the steric and electrostatic interactions at both sites were similar to those previously elaborated in the QSAR analyses. Both the QSAR and the CoMFA analyses showed that the steric interactions are similar at the PNMT active site and at the alpha2-adrenoceptor and that the electrostatic interactions were different at the two sites. This difference in electrostatic interactions might be responsible for the selectivity of THIQs bearing a nonlipophilic electron-withdrawing group at the 7-position. These QSAR and CoMFA results will be useful in the design of potent and selective (PNMT vs alpha2-adrenoceptor affinity) inhibitors of PNMT.     

The PingER project: active Internet performance monitoring for theHENP community

The extraordinary network challenges presented by high energy nuclear and particle physics experiments has created a need for network monitoring both to understand present performance and to allocate resources to optimize performance between laboratories, and the universities and institutes collaborating on present and future experiments. The resulting Internet end-to-end performance monitoring project is called PingER. The monitoring infrastructure reflects the wide geographical spread of the collaborations, and involves a large number of research and commercial networks. The architecture of the data acquisition and methodology of the analysis have evolved over several years, and are described here in their present state. The strengths and weaknesses of the project are reviewed, and the derived metrics are discussed in terms of their diagnostic functions. The observed short-term effects and long-term trends are reviewed, and plans for future developments are described     

What's in a manner of speaking? Children's sensitivity to partner-specific referential precedents.

Do young children form “referential pacts”? If a person has referred to an object with a certain term (e.g., the horse), will children expect this person to use this term in the future but allow others to use a different expression (e.g., the pony)? One hundred twenty-eight children between 3 and 5 years old co-operated with an experimenter (E1) to move toys to new locations on a shelf. E1 established referential terms for all toys in a warm-up game. Then, either the original partner, E1, or a new partner, E2, played a second game with the same toys. In this game, the experimenters referred to toys using either their original terms from the warm-up game or new terms. Children were slower to react to new terms than old, and this difference in reaction times was greater in the original partner condition (but only on the first trial). Children sometimes protested at the use of new terms, doing so regardless of their interlocutor's identity. We contrast these findings with those for adults and discuss their implications for the debate regarding the nature of referential pacts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association between socioeconomic status and metabolic syndrome in women: Testing the reserve capacity model.

Objective: Low socioeconomic status (SES) environments may impede the development of a bank of resources, labeled reserve capacity, and may also be stressful, thereby depleting available reserves. In consequence, lower SES persons may experience more negative emotions, leading to adverse health consequences. The authors tested the reserve capacity model in relation to the metabolic syndrome. Design: There were 401 initially healthy women who followed longitudinally for 12 years. Self-reported characteristics, stressors, and cardiovascular risk factors were measured repeatedly. Structural equation modeling was used to evaluate hypothesized relationships. Main Outcome Measure: Metabolic syndrome factor. Results: Confirmatory factor analysis verified reserve capacity as the aggregate of optimism, self-esteem, and social support, and negative emotion as the aggregate of depressive symptoms, anger, and tension. Structural equation modeling showed two pathways to the metabolic syndrome factor, (χ2(59) = 111.729, p ldf = 1.894; CFI = .956; RMSEA = .047): direct from low SES to the metabolic syndrome factor (B = -0.19, t = -3.24, p = .001); and indirect, from low SES to low reserve capacity to high negative emotions to the metabolic syndrome factor (B = -0.024, t = -2.05, p = .04). Conclusion: Low SES may increase risk for metabolic syndrome, in part, through reserve capacity and negative emotions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)