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The chemical composition of the surfaces of γ-irradiated polytetrafluoroethylene and polychlorotrifluoroethylene plates has been studied by X-ray photoelectron spectroscopy (XPS). In the chemical composition of irradiated polytetrafluoroethylene, the concentration of fluorine decreased and the concentrations of carbon and oxygen increased as a result of the degradation of the main polymer chain with the formation of low-molecular-weight compounds and the oxidation of free radicals stabilized on the surface of the irradiated polymer. The chemical composition of the polychlorotrifluoroethylene surface revealed by analyzing the XPS spectrum noticeably changed after γ-irradiation with a decrease in the concentration of carbon and an increase in the concentrations of fluorine, oxygen, and chlorine. [ABSTRACT FROM AUTHOR]

The action of accelerated 1–4-MeV protons on polychlorotrifluoroethylene in vacuum was accompanied by a preferential rupture of the main polymer chain with the release of more than 30 gaseous products, most of which were tetrafluoroethylene and chlorine- and fluorine-containing compounds. As a result of proton bombardment, the concentration of carbon on the polymer surface decreased and the concentrations of fluorine and chlorine increased. It has been shown that the incorporation of chlorine atoms into the structure of a perfluoropolymer changes the mechanism of its proton bombardment and helps to protect its macromolecule from the reaction of fluorine abstraction by accelerated protons with the formation of hydrogen fluoride. It has been found that irradiation with accelerated protons leads to changes in surface energy characteristics. [ABSTRACT FROM AUTHOR]

Abstract In operando Ru K edge X-ray absorption spectra were recorded at various cell voltages from specific regions of a direct methanol fuel cell (DMFC), such as methanol inlet, outlet and middle regions. From the linear combination fitting analysis, it was found that 50% of the Ru in the pristine Pt/Ru catalyst is in an oxidized form that matches with hydrated ruthenium oxide (RuO 2 ·xH 2 O). During the DMFC cycling, fraction of this oxide phase gets reduced and forms metallic Ru. Furthermore, it is observed that under normal DMFC operation at various cell voltages relatively a higher amount of RuO 2 phase is present at the methanol inlet compared to the methanol outlet. This difference in the amount of RuO 2 phase observed translates into inhomogeneous distribution of potential/current within a single cell. The amount of RuO 2 phase increased further when the DMFC was subjected to fuel starvation conditions (very high anode potential). Again compared to the methanol outlet region, a higher amount of RuO 2 phase was found at the methanol inlet. As RuO 2 is more prone to dissolution compared to metallic Ru, it can be concluded that methanol inlet region is more prone to Ru dissolution compared to methanol outlet region. Highlights • RuO 2 ·xH 2 O phase found throughout the DMFC cycling. • Amount of RuO 2 ·xH 2 O depends on the methanol concentration. • The highest amount of RuO 2 ·xH 2 O found at methanol inlet. • Fuel starvation increases the RuO 2 ·xH 2 O formation. • Degradation begins from the more active region like methanol inlet. [ABSTRACT FROM AUTHOR]

A carbon supported Pt catalyst with tetradecyltrimethylammonium bromide (TTAB) adsorbed to the nanoparticle surface was operated and tested as a cathode in a polymer electrolyte membrane fuel cell. The fuel cell with the TTAB@Pt/C catalyst showed a higher current relative to the amount of Pt used than the fuel cell with a commercial Pt/C catalyst. Besides, CO stripping evidenced that for the TTAB@Pt/C electrode large parts of the Pt surface were covered by TTAB. Hence, the fuel cell with the TTAB@Pt/C cathode showed a larger current related to the electrochemical active surface area as compared to the fuel cell with the commercial Pt/C cathode. This improvement in the ORR kinetics was further investigated by X-ray photoelectron and in-situ X-ray absorption spectroscopy, and was found to have been caused by two effects: (1) the presence of a metal-ligand charge transfer in the TTAB@Pt/C electrode and (2) the prevention of oxygen containing adsorbates which were being formed in large amounts on the Pt/C electrode. Furthermore, the latter effect also explains the higher stability observed for the TTAB@Pt/C compared to the Pt/C electrode. [ABSTRACT FROM AUTHOR]

The action of 1- to 4-MeV protons on a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP) in a vacuum is accompanied by the release of more than 25 gaseous products and a decrease in its thermal stability. During the course of proton bombardment, the predominant rupture of lateral C-CF bonds with the release of CF particles occurs along with the detachment of fluorine and hydrogen atoms yielding H and HF. Unlike polytetrafluoroethylene, a distinctive feature of the radiolysis of FEP is a decrease by a factor of 5 in the probability of fluorine detachment from the FEP macromolecule by accelerated protons. [ABSTRACT FROM AUTHOR]

Oxygen plasma treatment was applied on commercially available graphite felt electrodes based on rayon (GFA) and polyacrylonitrile (GFD). The formation of functional groups on the surface of the felt was confirmed by X-ray photoelectron spectroscopy measurements. The BET studies of the plasma treated electrodes showed no significant increase in surface area for both the rayon as well as the PAN based felts. Both plasma treated electrodes showed significantly enhanced V 3+ /V 2+ redox activity compared to the pristine electrodes. Since an increase of the surface area has been ruled out for plasma treated electrode the enhanced activity could be attributed to surface functional groups. Interestingly, plasma treated GFD felts showed less electrochemical activity towards V 5+/ V 4+ compared to the pristine electrode. Nevertheless, an overall increase of the single cell performance was still observed as the negative electrode is known to be the performance limiting electrode. Thus, to a great extent the present work helps to preferentially understand the importance of functional groups on the electrochemical activity of negative and positive redox reaction. The study emphasizes the need of highly active electrodes especially at the negative electrode side as inactive electrodes can still facilitate hydrogen evolution and degrade the electrolyte in VRFBs. [ABSTRACT FROM AUTHOR]

The aim of this study was to look at the effects of caffeine on strength performance and to examine any differences between sexes. Sixteen moderately active, resistance-trained individuals (10 males and 8 females) performed 2 trials (excluding a familiarisation trial). The effect of 5 mg/kg body mass (BM) caffeine or a placebo on bench press (BP) one repetition maximum (1RM), squat 1RM, the number of BP reps to failure at 40% 1RM (total weight lifted; TWL), pain rating (0-10) were recorded after each final successful lift. BP 1RM was significantly greater (P=0.016), with an increase of 5.91% for males and an increase of 10.69% for females. However, there was no sex difference in squat 1RM with males producing 130.3±27.8 and 134.0±28.9 kg and females producing 66.9±6.2 and 65.3±7.0 kg for placebo and caffeine, respectively. TWL tended to increase with caffeine for males from 1,246.8±704.9 to 1,545.5±920.3 kg; with females having no effect of caffeine (397.8±245.1 to 398.8±182.7kg; P=0.06). Caffeine had no effect on pain perception. This study found that 5 mg/kg BM caffeine improved BP 1RM in resistance-trained males and females. However, for TWL there was a tendency towards improvement in males only, suggesting a sex difference to caffeine ingestion for TWL. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, we succeeded in supporting predominantly cuboctahedral Pt nanoparticles onto high surface area carbons while maintaining their shape. These novel catalysts were applied in a realistic fuel cell set-up for the first time and showed remarkable fuel cell performance. A 95% fraction of cuboctahedral Pt nanoparticles was synthesized using tetradecyltrimethylammonium bromide (TTAB) as a stabilizer. Transmission electron micrographs of the synthesized samples demonstrated the presence of monodispersed cuboctahedral particles of 12 nm in size. Cyclic voltammetry (CV) studies of the unsupported cuboctahedral nanoparticles revealed the presence of Pt (110) and (100) facets. The shape-selected Pt nanoparticles were let to absorb onto Vulcan carbon by a simple dispersing procedure to obtain supported shape-selected Pt nanoparticles. Only by this gentle adsorption step of the surfactant-stabilized nanoparticles on the carbonaceous support material, the nanoparticles retained their shape. Finally an MEA was fabricated using the supported shape-selected nanoparticles and tested in a realistic H2-PEM fuel cell environment. In terms of Pt utilization, shape-selected Pt particles were found to be more effective by a factor of four in weight compared to the commercial catalyst. [Copyright &y& Elsevier]

Highlights: [•] The DBF showed a degree of desaturation in both tests after 1.5 and 3.5years. [•] GF and HCB moved toward EMDD homogeneity due to their similar mineral textures. [•] The DBF and HCB after 3years still have very different EMDD values. [•] The DBF and HCB have different mineral textures and compressibility limitations. [•] The DBF and HCB are not expected to come to either density or EMDD homogeneity. [ABSTRACT FROM AUTHOR]

This study provides a baseline from which changes in the chemistry of the atmosphere over Antarctica can be monitored under expected warming scenarios and continued intensification of industrial activities in the Southern Hemisphere. It is the first study to measure more than 25 chemical constituents in the surface snow and firn across extensive regions of Antarctica. We present major ion, trace element, heavy metal, rare earth element and oxygen isotope data from a series of surface snow samples and shallow firn sections collected along four US ITASE traverses across East and West Antarctica. In each sample we measure dissolved concentrations of Na+, K+, Mg2+, Ca2+, Cl-, NO-3, SO2-4, and MS- using ion chromatography and total concentrations of Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co, Na, Mg, Li, and K using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). We also measure δ18O by isotope ratio mass spectrometry. Satellite remote sensing measurements of microwave backscatter and grain size are used to assist in the identification of glaze/dune areas across Antarctica and determine if these areas can possibly contain useful chemical climate records. The majority of the non-glaze/dune samples in this study exhibit similar, or lower, concentrations to those from previous studies. Consequently, the results presented here comprise a conservative baseline for Antarctic surface snow chemical concentrations. The elements Cd, Pb, As and Bi are enriched across Antarctica relative to both ocean and upper crust elemental ratios. Local and global volcanic outgassing may account for the majority of the Bi measured in East and West Antarctica and for a significant fraction of the Cd and As. However, significant concentrations of Cd, Pb, and As remain across much of Antarctica. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the efficiency (in terms of energy use and carbon emissions) with which 5 different types of domestic water heating systems employed in the UK are able to produce hot water for sanitary use. A method of normalisation is employed allowing results from case studies with different systems and usage levels to be compared. Water heating appliances studied include gas boilers, a micro CHP, heat pumps, an immersion heater, and a solar thermal system. It is found that instantaneous production of hot water is much more efficient than delivery via tank storage for gas-fuelled systems. For electrical systems, an immersion heater is found to perform better in some circumstances than heat pumps and also has advantages when combined with a solar thermal system leading to the proposal that this combination offers the most potential as a low carbon method for domestic hot water provision in the long term. Opportunities are identified to improve the performance of all systems with storage through better control of heat inputs. Inconsistencies in, and problems of compliance with, established standards for mitigation of Legionella in hot water systems are also identified. [Copyright &y& Elsevier]

A critical review of published studies investigating the dielectric barrier discharge (DBD) treatment of four polymers widely employed in the packaging sector, namely: polyethylene (PE), polypropylene (PP), poly (ethylene terephthalate) (PET) and polystyrene (PS) is presented. The DBD treatment process operates at atmospheric pressure in air, and thereby offers a low cost method of enhancing the surface properties of polymers. The method is suitable for high volume in-line applications such as packaging. It has been reported that treatment doses as low as 0.01 J/cm2 result in significant increases in surface energy and wettability, leading to enhanced adhesive bonding and printing performance. Two critical issues limit the improvements obtained via the DBD processing of polymers. Firstly, DBD processing can produce a poorly adhered surface layer of low molecular weight material, which can then interfere with bonding and printing processes. Secondly, the properties of DBD treated polymers tend to revert towards that of the untreated state during storage. [ABSTRACT FROM AUTHOR]

The solution method was used to create polysulfone/carbon nanotubes composites. The effect of three solvents (NMP, DMF, and THF), treatments (nitric acid and ethanol) and surfactants (ODA and OCA) on CNT/ solvent stability was investigated. NMP and DMF resulted in improved stability compared to THF, and all CNT treatments improved stability. Four composites were produced with CNT loadings of 0—5 wt%: as-received CNT and nitric acid treated in THF, as-received CNT and OCA surfactant CNT in NMP. Optical, TEM, and electrical percolation measurements confirmed the role of CNT/solvent stability on the final composite dispersion. Tensile testing and thermal analysis confirmed the presence of residual solvent in all samples. [ABSTRACT FROM AUTHOR]

Abstract: Ru dissolution is one of the key issues in direct methanol fuel cells (DMFC). A used DMFC stack membrane electrode assembly (MEA) was analyzed using different analytical techniques like X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM) and EDX and different regions probed in the process. Catalyst powder from e.g. like methanol inlet, outlet and center were investigated and compared with the as-received commercial electrocatalyst and the pristine MEA after manufacture. The large oxidized ruthenium fraction in the anode catalyst was found to play a significant role in particle growth and ruthenium dissolution. Crossover ruthenium from the anode side was found to be dispersed everywhere in the cathode in its oxidized form, and thus can have a significant effect on the oxygen reduction activity (ORR). Although with XRD no significant structural changes were observed for the different regions of the MEA, TEM and EDX analysis showed the preferential precipitation of the Ru at the methanol outlet. [Copyright &y& Elsevier]

Objectives. Social support for physical activity is reliably associated with regular physical activity, however the social cognitive processes, particularly post‐intentional processes, that can explain this link have not been well characterized. In this study, we examined the extent to which the relationship between social support for physical activity and subsequent physical activity can be accounted for by planning processes. Design and method. The design was prospective observational and the sample consisted of 903 university students. Participants completed standard theory of planned behaviour, planning, and physical activity measures at 2 time points, approximately 7 weeks apart. A gender stratified multiple mediation model was conducted to test the study hypotheses. Results. A significant interaction between social support and gender was observed. This indicated that lower levels of social support for physical activity were associated with lower levels of physical activity at Time 2, for women only. In multiple mediation analysis, this was partly explained by the indirect effects of social support through perceived behavioural control and coping planning. Conclusion. These findings highlight the importance of interpersonal processes in understanding the post‐intentional social cognitive determinants of regular physical activity. It is likely that planning processes relating to physical activity are often influenced by those in the ongoing immediate social environment who support this behaviour. Future development of theory and interventions should take account of the socially interactive nature of planning processes. [ABSTRACT FROM AUTHOR]

Abstract: Microwave activated chemical bath deposition (MW-CBD) is a simple and novel technique in which the substrate is heated directly by microwaves and very well adhered layers are obtained. It has not been used previously for TiO2 deposition on metals. We show that it is possible to coat stainless steel with TiO2 using MW-CBD. Two different precursor solutions are used for TiO2 deposition on steel grade 316. TiO2 thin films on steel substrates were characterized using SEM and Raman spectroscopy. Raman analysis showed that amorphous TiO2 is obtained using the precursor solution based on TiOSO4; however, films show anatase crystal structure when using the precursor solution based on (NH4)2TiF6. Thermal treatment of the films improved crystallinity and also allowed iron diffusion from the steel substrate into the film. Crystalline phases that appeared due to heat treatment were identified from Raman spectra. MW-CBD allows simple low temperature coating of a metal substrate with TiO2 and this should be useful for a number of different applications. [Copyright &y& Elsevier]

Species sensitivity distributions (SSDs) are used globally to generate water quality guidelines (WQGs). In Canada, a suite of models has been endorsed for describing SSDs. However, these models may not be suitable for substances with multiple modes of toxic action such as pesticides. Pesticides can produce multimodal SSDs where sensitive target organisms comprise one mode of the SSD and non-target organisms comprise the remaining mode(s). Guidelines from this type of SSD might be estimated using only the most sensitive taxa or using a multimodal distribution. The multimodal method presented here uses all data meeting data quality criteria and is thus in keeping with the concept that data comprising an SSD are a random sample from the population of interest rather than a subset thereof. The bimodal method can simultaneously emphasize the more sensitive portion of the dataset by allowing estimation of WQGs using a statistical subset of the data. In the case of the atrazine dataset example, this allowed estimating a WQG emphasizing more sensitive taxa whereas no parametric models fit only the more sensitive data and the small sample size (5) precluded the use of nonparametric methods. [ABSTRACT FROM AUTHOR]

Study Design:Cross-sectional, paired cohort study.Objectives:To replicate the finding of impaired immunocyte function following spinal cord injury (SCI). To determine whether cellular immune function in SCI subjects with decentralized sympathetic nervous system (SNS) (T6 and above) varies from SCI subjects with intact SNS (below T6).Setting:University of Medicine and Dentistry of New Jersey–New Jersey Medical School, Newark, NJ, USA.Method:In vitro immune assays: (1) natural killer (NK) cell cytotoxicity using a K562 target cell line in a 4-h chromium51 release assay. The mean of three samples for each effector-to-target (E:F) ratio (25:1, 50:1, 100:1) was used in the analyses. (2) Cell enumeration was performed using commercially available antibodies and standard flow cytometry techniques.Results:Participation of 36 SCI subjects and 36 individually age- and sex-matched healthy controls. SCI subjects were stratified into two groups, that is, neurologic level of injury (NLI) at T6 or above (26 subjects) and NLI below T6 (10 subjects). No statistically significant differences were identified between NLI T6 and above and NLI below T6 groups for the NK cytotoxicity assay. There was a statistically significant reduction in NK cell numbers in all subjects with SCI as compared to their paired controls. There was a statistically significant reduction in NK cell cytotoxicity in SCI subjects, relative to the controls for E:F ratio of 100:1 (F=6.18, d.f.=34, P=0.02).Conclusion:We replicated the finding of decreased NK cell number and cytotoxicity in SCI subjects. The mechanism behind these findings needs to be further investigated, with the long-term goal of developing therapeutic strategies to improve immune function.Spinal Cord (2008) 46, 477–481; doi:10.1038/sc.2008.4; published online 12 February 2008 [ABSTRACT FROM AUTHOR]

This paper discusses the long term effects of dielectric barrier discharge (DBD) treatment on the surface properties of ethylene vinyl acetate (EVA) film. The EVA surface was characterised using contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and 180° peel tests. EVA subjected to two different treatment times was compared to as-received and solvent cleaned film. The long term stability of the surface modification induced by the DBD treatment was studied over a period of 466 days. On initial application of DBD treatment to the EVA surface an increased wettability was observed, evident from a decreased water contact angle, improved peel strength when bonded, and an increased level of carbon–oxygen moieties measured using XPS. However, over the storage period of 466 days the material reverted to almost its original state with the contact angle being only ∼3° lower than that of as-received EVA compared to a difference ∼25° directly after treatment. AFM measurements showed that the treatment had a slight smoothing effect on the surface topography. [ABSTRACT FROM AUTHOR]

Purpose. Disability is conceptualized as behaviour by psychological theory and as a result of bodily impairment by medical models. However, how people with disabilities conceptualize those disabilities is unclear. The purpose of this study was to examine disability representations in people with mobility disabilities. Method. Thirteen people with mobility disabilities completed personal repertory grids (using the method of triads) applied to activities used to measure disabilities. Ten judges with expertise in health psychology then examined the correspondence between the elicited disability constructs and psychological and medical models of disability. Results. Participants with mobility disabilities generated 73 personal constructs of disability. These constructs were judged consistent with the content of two psychological models, namely the theory of planned behaviour and social cognitive theory and with the main medical model of disability, the International Classification of Functioning Disability and Health. Conclusions. Individuals with activity limitations conceptualize activities in a manner that is compatible with both psychological and medical models. This ensures adequate communication in contexts where the medical model is relevant, e.g., clinical contexts, as well as in everyday conversation about activities and behaviours. Finally, integrated models of disability may be of value for theory driven interdisciplinary approaches to disability and rehabilitation. [ABSTRACT FROM AUTHOR]

This paper investigates potential exposure to endotoxin in drinking water through the inhalation of aerosols generated by showers and humidifiers. Adverse health effects attributable to the inhalation of airborne endotoxin in various occupational settings are summarized, as are controlled laboratory inhalation studies. Data from investigations estimating aerosolization of particulate matter by showers and humidifiers provide a basis for similar analyses with endotoxin, which like minerals in water, is nonvolatile. A theoretical assessment of the inhalation of aerosolized endotoxin showed that while the likelihood of an acute response while showering is minimal, the same is not true for humidifiers. Ultrasonic and impeller (cool mist) humidifiers efficiently produce large numbers of respirable particles. It is predicted that airway inflammation can occur if humidifier reservoirs are filled with tap water, sometimes even at typical drinking water distribution-system endotoxin concentrations. Higher endotoxin levels occasionally found in drinking water (>1,000 EU/ml) are very likely to induce symptoms such as chills and fever if used as humidifier feed water. While it is unlikely that treated drinking water would contain extremely high endotoxin levels occasionally observed in cyanobacterial blooms (>35,000 EU/ml), the potential for serious acute health consequences exist if used in humidifiers. [ABSTRACT FROM AUTHOR]

This paper proposes a novel measurement method for investigating the high-temperature peel properties of medical packaging materials. Samples were attached to a temperature-controlled aluminium block fitted to a tensile testing machine allowing the temperature dependence of peel strength to be investigated. The mechanical performance of the seals at elevated temperatures is critical. Medical packaging materials are subjected to a range of elevated temperature conditions during the materials lifetime. High-temperature peel strength is an important parameter during pouch manufacture, sterilisation and also in shipping/storage. The proposed method allows the temperature dependence of seal behaviour to be investigated by adapting standard tensile testing equipment. The technique was used to determine the peel strengths of two grades of wax/polymer-type adhesive coated (Tyvek®) at elevated temperatures. The peel strength was found to decline with a 50% reduction in peel strength observed between ambient and 43°C. This demonstrates the importance of quantifying the effect of temperature on mechanical behaviour. [ABSTRACT FROM AUTHOR]

The Tunnel Sealing Experiment (TSX) was an international project developed by Canada, Japan, France, and the United States. The TSX consisted of a clay bulkhead and a concrete bulkhead. The two bulkheads were at opposite ends of a 12-m-long sand-filled chamber. The heating phase involved the circulation of heated water through the TSX chamber to raise the temperature of the sealing system. This was done to evaluate the influence of elevated temperature on the performance of the bulkheads. Numerical analyses to simulate the thermohydromechanical evolution of the clay bulkhead and the surrounding rock of the TSX were performed using MOTIF finite-element program and compared with measured data. This paper focuses on a preliminary interpretation of the results from the fully coupled thermohydromechanical modeling of the clay bulkhead and the adjacent rock during heating. Discussion of the issues that will affect the ability to model a field application is provided in the course of comparing simulated and measured results. [ABSTRACT FROM AUTHOR]

Employment in a children's hospital of a major medical center can be stressful for healthcare providers, especially when faced with potential losses of pediatric and adolescent patients. Although it seems natural to believe that emotional distress following the death of a patient would be addressed, this is not always the case. The current manuscript presents results of a survey of healthcare providers at Shands Children's Hospital at the University of Florida, a not for profit teaching hospital. Hospital staff (N = 94) responded to the survey with a 100% return rate. Responses identified situations considered to be stressful, and described how healthcare providers in this setting dealt with these incidents. Regarding existing hospital resources, respondents reported using multidisciplinary patient care conferences, social workers, and co-workers most often, as sources of support. Respondents also provided a lengthy listing of recommendations for improvement. Addressing the issues presented in this study may result in improved employee retention and lower overall turnover rates. [ABSTRACT FROM AUTHOR]

Objective: To examine the relationships between TNF-alpha, obesity, and insulin resistance among prepubescent children.Design: Cross-sectional study.Setting and Subjects: Data were collected from 112 nondiabetic Latino schoolchildren from public schools in three South Florida communities. Of the enrolled participants, 43.8% were obese (BMI 95th percentile) and 51.8% presented with a family history of type 2 diabetes mellitus (T2DM). With one exception, all demonstrated normal glucose tolerance.Interventions: Plasma TNF-alpha levels were determined with enzyme-linked immunosorbance assay (ELISA). Homeostasis model assessment (HOMA-IR) was calculated as an index of insulin resistance. Mean levels of TNF-alpha among obese vs nonobese children were compared with a one-way analysis of variance with two groups, and the association between TNF-alpha and HOMA-IR was assessed with a Pearson's correlation.Results: Higher circulating TNF-alpha levels were revealed among nonobese vs obese children. Nonobese girls demonstrated higher TNF-alpha levels than obese girls, whereas there were no significant differences for boys. There were no significant differences after stratifying for family history of T2DM. There was a modest relationship between increased TNF-alpha levels and decreased insulin resistance.Conclusions: The observed elevated circulating TNF-alpha concentrations among leaner participants may reflect an inflammatory process that has been associated with higher levels of physical fitness in both adults and prepubescent children. This effect may remain stronger for prepubescent girls, and the mechanism may be attenuated by the hormonal changes that occur with the onset of puberty. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: To examine the relationships between TNF-a, obesity, and insulin resistance among prepubescent children. DESIGN:: Cross-sectional study. SETTING AND SUBJECTS:: Data were collected from 112 nondiabetic Latino schoolchildren from public schools in three South Florida communities. Of the enrolled participants, 43.8% were obese (BMI 95th percentile) and 51.8% presented with a family history of type 2 diabetes mellitus (T2DM). With one exception, all demonstrated normal glucose tolerance. INTERVENTIONS:: Plasma TNF-a levels were determined with enzyme-linked immunosorbance assay (ELISA). Homeostasis model assessment (HOMA-IR) was calculated as an index of insulin resistance. Mean levels of TNF-a among obese vs nonobese children were compared with a one-way analysis of variance with two groups, and the association between TNF-a and HOMA-IR was assessed with a Pearson's correlation. RESULTS:: Higher circulating TNF-a levels were revealed among nonobese vs obese children. Nonobese girls demonstrated higher TNF-a levels than obese girls, whereas there were no significant differences for boys. There were no significant differences after stratifying for family history of T2DM. There was a modest relationship between increased TNF-a levels and decreased insulin resistance. CONCLUSIONS:: The observed elevated circulating TNF-a concentrations among leaner participants may reflect an inflammatory process that has been associated with higher levels of physical fitness in both adults and prepubescent children. This effect may remain stronger for prepubescent girls, and the mechanism may be attenuated by the hormonal changes that occur with the onset of puberty. SPONSORSHIP:: This research was supported, in part, by a clinical research grant from the American Diabetes Association, as well as NIMH NRSA # 5T32 MH18917-09.European Journal of Clinical Nutrition (2004) 58, 696-699. doi:10.1038/sj.ejcn.1601852 [ABSTRACT FROM AUTHOR]

Based on weight loss in water, 24 h is recommended for Tubifex tubifex gut clearance. Biota-to-sediment accumulation factors (BSAFs) in gut-cleared T. tubifex following six weeks of exposure to Cd-, Ni-, and Pb-spiked sediment were 12.4, 3.0, and 19.0, respectively. Tissue Ni concentrations peaked after 12 h, whereas Cd and Pb were accumulated for the duration of the exposure. Tubifex tubifex were transferred to either water (24 h) or sediment (10 weeks) to monitor changes in internal metal concentrations. After 24 h in water, only Ni concentration had declined significantly (p < 0.05), suggesting that the majority of Ni was associated with the gut content, while Cd and Pb were accumulated in the tissues. Metal depuration in sediment was described with twocompartment, first-order kinetic models (r² 5 0.7-0.8; p < 0.001), indicating that T. tubifex has both a quickly depurated and a more tightly bound pool of accumulated metal. Tubifex tubifex were also exposed to sediment spiked with just Cd (3.66 μmol/g). Cadmium uptake and induction of metallothionein-like protein (MTLP) were rapid; both parameters were significantly elevated within 24 h of exposure. Metallothionein-like protein (8.7 ± 1.8 nmol/g) and Cd (60.8 ± 11.0 μmol/g) reached maximum concentrations after 96 h and four weeks, respectively. [ABSTRACT FROM AUTHOR]

We examined the association of primary or nonprimary sexual partner relationship status on sexual risk behaviors, including condom use, among Latina women who are at self-disclosed increased heterosexual risk for human immunodeficiency virus (HIV) infection. Data were collected via structured interviews of 187 Puerto Rican women, aged 18-35, who attended a health clinic in the Bronx, New York. Approximately 13% of participants reported sexual activities with both primary and nonprimary sexual partners during the 6 months prior to the interview. Primary or nonprimary sexual partner status was associated with significant differences in frequency of condom use during anal sex and oral-penile sex, with more frequent condom use reported during these sexual activities with nonprimary sexual partners. Thus, potential contextual differences associated with primary or nonprimary relationship status may represent important factors to consider when designing interventions to facilitate HIV-protective behaviors among populations of urban women identified at increased heterosexual risk for HIV infection. [ABSTRACT FROM AUTHOR]

As disposal options for sludges become more difficult to find and more expensive to operate, those relying on some form of thermal treatment are becoming more commercially attractive. The incentive, especially for more heavily populated countries, is the production of treated solids suitable for beneficial application to land. It is the level of treatment required to achieve this cost effectively which has been the focus of much of the research in this field. There are now several commercially available plants designed to thermally treat sludges and many have been in full scale operation for a number of years. One of the auxiliary claims often made by proponents of such treatments, is that the resultant sludges are more amenable to dewatering and therefore easier and cheaper to handle. In this work we have used a novel filtration rig to obtain complete sets of filtration data for different sludges. Historically sludge characterisation has been achieved by measurement of an empirical Capillary Suction Time (CST) parameter, however with the new filtration apparatus it is now possible to obtain fundamental sludge characteristics across a wide range of volume fractions in hours not days. We have applied this technology to characterise different sludge samples before and after thermal treatment under different sets of operating conditions (pH, temperature and pressure) to simulate some of the commercially available thermal treatment technologies. We have also examined the effects of various chemical oxidants (hydrogen peroxide and Fenton's reagent) used as pretreatments to the thermal process and attempted to compare their cost efficiencies. The results show that the physical structure of the sludge is irreversibly altered by decreasing the pH or heating to temperatures in excess of 150°C in a way which significantly enhances the dewaterability of the material. The treated sludge not only has a higher permeability but also has a higher final per cent solids (often in the autothermal region). In contrast the amounts of chemical additives used in pretreatment to achieve similar effects are cost prohibitive. [ABSTRACT FROM AUTHOR]

Two large-scale sealing experiments were conducted at Atomic Energy of Canada Limited's Underground Research Laboratory at Lac du Bonnet, Manitoba. The rate of water uptake in densely compacted sand–clay buffer materials proposed for use in a deep geologic repository for spent nuclear fuel was monitored. The buffer–container experiment examined the influence of heat on the performance of a large mass of buffer. Temperatures, water contents, and total and hydraulic pressures within and surrounding the installation were monitored for approximately 2.5 years. Local groundwater pressures increased as a result of rising temperatures. Water uptake and redistribution occurred in the buffer due to drying shrinkage close to the heater and counter-acted swelling due to an increase in water content near the rock–buffer interface. The isothermal test (ITT) allowed natural groundwater uptake from the surrounding rock mass under isothermal conditions. It was monitored for a period of 6.5 years and is the first, and longest running test of its kind yet conducted in the world. During its operation, the ITT (for as yet unconfirmed reasons) experienced a 35% decrease in the rate of water supply relative to that measured prior to experiment installation. This decrease impacts on the time required for saturation to be achieved.Key words: buffer, bentonite, underground research laboratory, instrumentation.Deux essais d'étanchéité à grande échelle ont été conduits au Laboratoire de recherche souterrain de l'Énergie atomique du Canada au lac du Bonnet, Manitoba. On a mesuré la vitesse d'absorption d'eau dans des matériaux tampons formés de sable et argile densément compacts devant être utilisés dans un dépôt géologique profond pour le combustible nucléaire irradié. L'expérience tampon–conteneur a permis d'examiner l'influence de la chaleur sur la performance d'une large masse de tampon. Les températures, teneurs en eau, pressions totales et hydrauliques à l'intérieur et autour de l'installation ont été mesurées durant environ 2,5 années. Les pressions de l'eau souterraine locale ont augmenté à cause de l'augmentation de la température, une absorption et une redistribution se sont produites dans le tampon à cause du séchage et du retrait près des points chauds d'une part, et de l'action inverse du gonflement dû à l'augmentation de la teneur en eau près de l'interface roc–tampon d'autre part. L'essai isothermique a permis l'absorption de l'eau souterraine naturelle venant du massif rocheux dans des conditions isothermiques. Des mesures ont été prises durant une période de 6,5 années, et cet essai est le premier et le plus long essai de ce type à être réalisé jusqu'à ce jour dans le monde. Au cours de son opération, cet essai a subi, pour des raisons encore non confirmées, une diminution de 35 % de la vitesse de son alimentation en eau par rapport à celle mesurée avant la mise en place de l'expérience. Ceci a des impacts sur le temps requis pour atteindre la saturation.Mots clés : tampon, bentonite, Laboratoire de recherche souterrain, instrumentation.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Previous research has shown that both prosodic and content variations in speech register are important when addressing all individuals. Motherese speech register has been associated with higher levels of perceived disability and is viewed more negatively by individuals with a history of head injury. This research was conducted to investigate the separate contributions of content and prosody in producing differential response to speech by individuals with and without a history of head injury. Participants included 210 introductory psychology students with and without head injuries. No significant demographic differences were found between these groups. Participants listened to 4 sets of audiotaped instructions from a fictitious home economics teacher containing prosodic and content variations. Afterward, they rated the teacher on the following dimensions: liking, positive impact, negative impact, grade level being taught, and whether they would recommend hiring this teacher. Analysis of variance revealed there were no significant group differences between participants rating with normal speech. As expected, both groups favored the normal speech register over motherese. However, the group with head injuries consistently rated the speech with motherese content as more negative, less likable, less likely to hire, and aimed at a lower grade level. Participants with head injuries also rated the speech register with motherese prosody as less likable and less likely to hire. These results suggest that when addressing individuals with head injuries, both what you say and how you say it are important. [ABSTRACT FROM AUTHOR]

Focuses on a plant growth-promoting bacterium with the characteristics of decreasing nickel toxicity in seedlings. Resistance of bacterium; Acceleration of pollution of the biosphere by toxic metals; Indentification of this plant growth-bacterium.

Provides information on a study which found that bresiliid shrimp postlarvae are very widely dispersed around the Broken Spur vent field and extend into the next Mid-Atlantic Ridge (MAR) segment and the Atlantis Fracture Zone beyond. Methods of the study; Results and discussion.

Juvenile rainbow trout (initial mean body weight 17 g) reared on practical trout diets containing different levels of available carbohydrate for 8-24 weeks were assayed for liver function based on the time required to recover from the ariaesthetics tricaine methanesulphonate (MS222), 2-phenoxyethanol (2PE) and tertiary-amyl alcohol (TAA), as well as plasma clearance of 35S-sulphobromo- phthalein (BSP). Liverfbody weight ratios (LBW) and percentage liver glycogen content (LG) increased in a linear manner with increased available carbohydrate. The mean recovery time (MRT) of trout anaesthetized with 2PE and TAA increased linearly with increased LBW and LG. No difference was observed in the MRT of trout anaesthetized with MS222 which is not metabolized in the trout liver. There was a significant linear regression of the biological half-life of plasma BSP on LBW (MR2 = 957) and LG (MR2 = 99'6). The results indicate that increased liver glycogen and liver weight due to higher levels of available carbohydrate affect the liver function of rainbow trout. These liver function tests may be applicable in determining acceptable levels of available carbohydrate in practical trout diets. [ABSTRACT FROM AUTHOR]

Provides information on some of the key resources which can be used in the integration of service learning practices. Indepth look at some of the resources which can be used; Addresses for Web sites which can be used to acquire information.

In the course of γ-irradiation at 77 K, polyvinyl alcohol accumulates alkyl radicals (formed upon hydrogen atom abstraction) and radical anions (resulting from electron addition to the acetate group remaining after the saponification of polyvinyl acetate in the course of polyvinyl alcohol production on its basis). Upon the radiolysis of polyvinyl alcohol at 300–341 K, polyenyl radicals with a singlet spectrum were detected in the EPR spectrum in addition to the triplet of alkyl radicals. [ABSTRACT FROM AUTHOR]

The effect of MeV protons on the surface properties of a low-density polyethylene film was studied using EPR spectroscopy and thermomechanical spectrometry. The diblock semicrystalline structure of polyethylene was preserved upon proton irradiation; the molecular weight decreased, and the weight fraction of the crystalline modification increased. In the EPR spectrum of the irradiated polymer, allyl radicals were predominantly detected. At high proton fluences, the hyperfine structure disappeared from the EPR spectra, and they turned into a singlet with a line width of 4.1 or 3.5 mT as recorded at 23 and –196°C, respectively. [ABSTRACT FROM AUTHOR]

The irradiation of a poly(vinylidene fluoride) (PVDF) plate with γ-rays up to 100 kGy leads to the breaking of the chain and the formation of unsaturated bonds but practically does not have any effect on the conformation composition of PVDF macromolecules. The main conformer, as in native PVDF, is the β form. Irradiation with an IR laser leads to a noticeable carbonization of PVDF macromolecules and is accompanied by a structural transition of polymer macromolecules from the β conformer to the α conformer. In the IR spectrum of the powdered product from laser ablation of PVDF, in addition to the absorption bands of the ablation crater, absorption bands from the parent PVDF are still present. [ABSTRACT FROM AUTHOR]

Patients with type 2 diabetes mellitus (T2D) present an increased risk for cardiovascular (CV) complications. In addition to improvement in glycaemic control, glucose-lowering therapies, such as glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-dependent glucose cotransporter (SGLT)-2 inhibitors, have been shown to significantly reduce CV events. In 2008, the US Food and Drug Administration mandated that all new glucose-lowering drugs undergo CV outcomes trials (CVOTs) to determine their CV safety. These trials have largely demonstrated no major CV safety concerns. Most notably, the GLP-1RAs and SGLT-2 inhibitors have been found to be not only safe, but also cardioprotective compared to placebo. The SGLT-2 inhibitors have opened a new perspective for clinicians treating patients with T2D and established CV disease in light of their 'pleiotropic' effects, specifically on heart failure, while GLP-1RAs seem to present more favourable effects on atherosclerotic events. In this review, we discuss the role of GLP-1RAs and SGLT-2 inhibitors to reduce CV risk in T2D patients and suggest an individualized therapeutic approach in this population based on the presence of metabolic and CV comorbidities. [ABSTRACT FROM AUTHOR]

We report the effect of preliminary γ-irradiation of polyethylene (PE) and ethylene-propylene copolymer (CEP) on the kinetics of polymer ablation under CO laser irradiation. The rate of PE ablation exceeds the rate of CEP ablation at all doses of γ-irradiation. The ablation rate of the polymers can be approximated by a linear function in the initial stage, and the rate reaches a constant value in the second stage of ablation. The rate of laser ablation increases linearly with the dose of preliminary γ-irradiation in both stages of the kinetics. For PE ablation, the duration of the linear increase in rate decreases with increase in preliminary radiolysis dose. The morphology of the crater surface formed during the laser ablation of γ-irradiated polymers is characterized by a more diverse structure. [ABSTRACT FROM AUTHOR]

Carbon felt electrodes for vanadium redox flow batteries are obtained by the graphitization of polyacrylonitrile based felts at different temperatures. Subsequently, the surface of the felts is modified via thermal oxidation at various temperatures. A single-cell experiment shows that the voltage efficiency is increased by this treatment. Electrode potentials measured with reference electrode setup show that this voltage efficiency increase is caused mainly by a reduction of the overpotential of the negative half-cell reaction. Consequently, this reaction is investigated further by cyclic voltammetry and the electrode activity is correlated with structural and surface chemical properties of the carbon fibers. By Raman, X-ray photoelectron and near edge X-ray absorption fine structure spectroscopy the role of edge sites and oxygen containing functional groups (OCFs) for the electrochemical activity are elucidated. A significant activity increase is observed in correlation with these two characteristics. The amount of OCFs is correlated with structural defects (e.g. edge sites) of the carbon fibers and therefore decreases with an increasing graphitization degree. Thus, for the same thermal oxidation temperature carbon fibers graphitized at a lower temperature show higher activities than those graphitized at a higher temperature. [ABSTRACT FROM AUTHOR]

Novel stretchable conducting films were prepared by depositing gold layers onto polymer nano-composites substrates formed by in-situ crosslinking of polydimethylsiloxane (PDMS) in the presence of multiwall carbon nanotubes (MWNT). The MWNT content interferes with the PDMS cure reaction giving variations in thermal degradation, solvent swelling, mechanical and electrical properties. Tensile cycling experiments were carried out on the gold-coated PDMS and nano-composite substrates SEM analysis and electrical measurements demonstrated that the crack widening and increased electrical resistance observed during strain cycling were reversible. The inclusion of 8% MWNT into PDMS brought more micro-cracking in the gold layer yet reduced the electrical resistance of the gold-coated samples by 172X at 5% strain, 38X at 10% strain and 19X at 20%. Hence, this improvement in conduction is attributed to assisted-conduction through the MWNT loaded substrate. This mechanism results in a more stable and reproducible electrical behaviour, making electrical conduction less critically dependent on defects in the gold layer. [ABSTRACT FROM AUTHOR]

The influence of ultraviolet (UV) irradiation on creosote toxicity was investigated with the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1, and two indicator dyes, alamar Blue(TM) and 5-carboxyfluorescein diacetate acetoxymethyl ester. These monitor redox potential and membrane integrity, respectively. After solubilization andchemical analysis, creosote was presented to cells in the dark to measure cytotoxicity or concurrently with UV irradiation to evaluate photocytotoxicity. Additionally, creosote was photomodified by 2 h of UV irradiation before presentation to cells in the dark or together with UV. Cytotoxicity was detected only at high nominal creosote concentrations, but photocytoxicity occurred at creosote concentrations 35-fold lower, All the aromatic hydrocarbons in creosote appeared to contribute to cytotoxicity, but photocytotoxicity was due only to the fluoranthene, pyrene, anthracene, and benzo[a]anthracene in the mixture. Photomodified creosote was much more cytotoxic than intact creosoteand this difference was most pronounced in the alamar Blue assay. Likely, this was due to photomodification products that impaired the mitochondrial electron transport chain. Photomodified creosote was slightly less photocytotoxic than intact creosote. Overall these results indicate that UV irradiation potentially enhances the toxicity of creosote in fish in several different but significant ways. [ABSTRACT FROM AUTHOR]