Electrocatalytic oxidation of methanol on platinum microparticles in polypyrrole

The oxidation of methanol on gold electrodes modified with polypyrrole and platinum is reported. These electrodes were characterized by cyclic voltammetry and by 12h polarizations in methanol solutions. They were found to give higher currents and lower rates of drift than electrodes of platinum and platinized gold. The effect of varying the amount of platinum deposited is also discussed.     

Software cost estimation with incomplete data

The construction of software cost estimation models remains an active topic of research. The basic premise of cost modeling is that a historical database of software project cost data can be used to develop a quantitative model to predict the cost of future projects. One of the difficulties faced by workers in this area is that many of these historical databases contain substantial amounts of missing data. Thus far, the common practice has been to ignore observations with missing data. In principle, such a practice can lead to gross biases and may be detrimental to the accuracy of cost estimation models. We describe an extensive simulation where we evaluate different techniques for dealing with missing data in the context of software cost modeling. Three techniques are evaluated: listwise deletion, mean imputation, and eight different types of hot-deck imputation. Our results indicate that all the missing data techniques perform well with small biases and high precision. This suggests that the simplest technique, listwise deletion, is a reasonable choice. However, this will not necessarily provide the best performance. Consistent best performance (minimal bias and highest precision) can be obtained by using hot-deck imputation with Euclidean distance and a z-score standardization     

Phylogenetic analysis of tnpR genes in mercury resistant soil bacteria: the relationship between DNA sequencing and RFLP typing approaches

The purpose of this study was to characterize hepatic cytochrome P450 induction in the dog by phenobarbital, beta-naphthoflavone, dexamethasone, and isoniazid using catalytic activities and Western blots with antibodies prepared against rat cytochrome P450 isozymes. Male beagle dogs were treated with phenobarbital (10 mg/kg for 2 days and 30 mg/kg for the following 5 days), beta-naphthoflavone (50 mg/kg for 5 days), or isoniazid (10 mg/kg for 2 days and 30 mg/kg for the following 5 days). Female beagle dogs were treated with dexamethasone (50 mg/kg for 5 days). Increases in the liver/body weight ratio were observed after treatment of dogs with phenobarbital (133% of control) and dexamethasone (153%). Total cytochrome P450 content was increased as a percentage of control after treatment with phenobarbital (264%) and (3-naphthoflavone (186%), while it slightly decreased after treatment with isoniazid (54%) and dexamethasone (71%). Dog liver microsomes hydroxylated testosterone mainly at the 6-beta and 16-alpha positions but also at the 6-alpha-, 15-beta-, 15-alpha-, 16-beta-, 18-, 2-beta-, and 17-positions. There were no sex differences in terms of regio-selectivity of testosterone metabolism between control male and female dogs. Treatment of dogs with phenobarbital produced increases in 6-beta- (184%), 16-alpha- (379%), 16-beta- (210%), 18- (195%), and 2-beta-testosterone (203%) hydroxylase and pentoxyresorufin 0-dealkylase (651%) activities. On Western blots, phenobarbital treatment produced induction of P450 3A- and 2B1-related proteins. Although treatment with dexamethasone resulted in a large increase in liver weight, no significant increase in P450 3A-related protein or 6-beta-hydroxylase activity was detected. However, dexamethasone and isoniazid treatment produced slight increases in chlorzoxazone hydroxylase activity. Treatment with isoniazid induced a P450 2E1-related protein. Treatment with (beta-naphthoflavone produced increases that were 689 and 357% of control in ethoxyresorufin 0-deethylase and chlorzoxazone hydroxylase activities, respectively. Beta-Naphthoflavone treatment increased the amount of two proteins immunochemically related to the cytochrome P450 1A subfamily. Thus, although generally similar to other species, the response of the dog to cytochrome P450 inducers differs significantly from the rat and human in some cases.     

HIV/AIDS training and continuing education for psychologists.

The HIV infection and AIDS pandemic presents professional disciplines, including psychology, with unique challenges. The authors review the literature on education concerning HIV/AIDS in doctoral psychology programs, internships, and continuing education efforts in psychology and other disciplines. Recommendations are offered regarding the process and content of continuing education for psychologists regarding HIV and AIDS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The design and testing of a composite lower limb prosthesis

In unilateral lower limb prosthetic gait, the intact limb, together with the hip on the affected side, strive to compensate for the loss of the missing below-knee musculature. The resultant abnormal gait patterns can eventually lead to pathologies of the spine and other joints. The aim of this research was to design a trans-tibial dynamic elastic response (DER) prosthesis which could simulate the power generation and absorption properties of an intact foot and shank segments. A carbon fibre sickle-shaped prosthesis was developed in which the strain energy from the early part of the stride was stored, and was released again at the point of take-off, to simulate the action of the missing musculature. Stress analysis techniques were used in the design of the prosthesis, for the purposes of computing and maximizing the strain energy of the elements. A force transducer was designed into the prosthesis to verify the analysis. Video motion analyses of the prosthesis were carried out in order to determine the most appropriate shape that would reduce gait asymmetries. The research shows that biomechanical techniques, together with good engineering design and the selection of modern materials, can lead to a prosthesis which approaches the function of a natural foot.     

Social networks and partner stress as predictors of adherence to medication, rehabilitation attendance, and quality of life following acute coronary syndrome.

Objective: This study examined whether social network size and partner stress predicted medication adherence, cardiac rehabilitation attendance, and quality of life 12 months following hospitalization for an acute coronary syndrome (ACS). Design: ACS patients (N = 193, M age = 60.6 years, SD = 11.4 years, 23% female) were recruited shortly following admission to 4 local hospitals. A prospective design was employed with follow-up data collected 12 months following hospital admission. Main Outcome Measures: Data were gathered on social network size and partner stress. The main outcomes assessed at 12 months were medication adherence, cardiac rehabilitation attendance, and quality of life (Short Form 36). Results: Partner stress predicted medication nonadherence, odds ratio: 2.89, (95% CI = 1.21, 6.95). ACS patients with large social networks were more likely to attend rehabilitation, odds ratio: 3.42, (95% CI = 1.42, 8.25). Analyses were adjusted for age, gender, clinical risk scores, readmission/recurrence, and negative affectivity. Both partner stress and smaller social network size were associated with poorer quality of life. Conclusion: Social network size and partner stress may partly exert their influence on coronary heart disease morbidity and mortality through recovery behaviors and maintenance of quality of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental Health Professionals' Disability Competence: Measuring Self-Awareness, Perceived Knowledge, and Perceived Skills.

Objective: To describe mental health professionals' self-reported competence when working with clients with disabilities. Study Design: Survey administered with a measure of social desirability. Participants and Setting: One hundred eight professionals in counseling offices, disability services offices, and doctoral counseling programs. Main Outcome Measure: Competence as self-reported on the Counseling Clients With Disabilities Survey (CCDS). Results: CCDS scores paralleled participants' disability experience. Participants reported most competence in awareness, less competence in knowledge, and least competence in skills. Neither socially desirable responding nor years of experience accounted for these results. Conclusions: Findings indicate the need for mental health professionals to develop (a) awareness/beliefs/attitudes toward disability, (b) knowledge of disability and disability-related issues, and (c) skills/behaviors working with clients with disabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distribution, diversity and evolution of the bacterial mercury resistance (mer) operon

Mercury and its compounds are distributed widely across the earth. Many of the chemical forms of mercury are toxic to all living organisms. However, bacteria have evolved mechanisms of resistance to several of these different chemical forms, and play a major role in the global cycling of mercury in the natural environment. Five mechanisms of resistance to mercury compounds have been identified, of which resistance to inorganic mercury (HgR) is the best understood, both in terms of the mechanisms of resistance to mercury and of resistance to heavy metals in general. Resistance to inorganic mercury is encoded by the genes of the mer operon, and can be located on transposons, plasmids and the bacterial chromosome. Such systems have a worldwide geographical distribution, and furthermore, are found across a wide range of both Gram-negative and Gram-positive bacteria from both natural and clinical environments. The presence of mer genes in bacteria from sediment cores suggest that mer is an ancient system. Analysis of DNA sequences from mer operons and genes has revealed genetic variation both in operon structure and between individual genes from different mer operons, whilst analysis of bacteria which are sensitive to inorganic mercury has identified a number of vestigial non-functional operons. It is hypothesised that mer, due to its ubiquity with respect to geographical location, environment and species range, is an ancient system, and that ancient bacteria carried genes conferring resistance to mercury in response to increased levels of mercury in natural environments, perhaps resulting from volcanic activity. Models for the evolution of both a basic mer operon and for the Tn21-related family of mer operons and transposons are suggested. The study of evolution in bacteria has recently become dominated by the generation of phylogenies based on 16S rRNA genes. However, it is important not to underestimate the roles of horizontal gene transfer and recombinational events in evolution. In this respect mer is a suitable system for evaluating phylogenetic methods which incorporate the effects of horizontal gene transfer. In addition, the mer operon provides a model system in the study of environmental microbiology which is useful both as an example of a genotype which is responsive to environmental pressures and as a generic tool for the development of new methodology for the analysis of bacterial communities in natural environments.