Evaluating the Sorption Kinetics of Polychlorinated Biphenyls in Powdered and Granular Activated Carbon.

Activated carbon (AC) has been applied widely in water treatment as a strong sorbent for organic contaminants and, more recently, in-situ treatment and capping for remediating legacy contaminants. In some sediment environments, the sorption kinetics onto AC may significantly impact remedial performance, particularly for large, highly hydrophobic contaminants such as PCBs, but there is limited kinetic data on such compounds. In this study, batch experiments were conducted over 52 weeks to measure PCB adsorption kinetics on 2 ACs in granular (1.1 mm diameter) and powdered (0.02 mm) form using polydimethylsiloxane (PDMS) fibers to measure aqueous concentrations over time. The experiment was conducted in glass containers with water at known PCB concentration and containing 10 mg/L natural organic matter (NOM) and activated carbon. Blanks without activated carbon were used to estimate kinetics and equilibrium uptake to PDMS and NOM. The PDMS measured aqueous concentration in AC containing slurries was then used to estimate kinetics and equilibrium uptake of the various PCBs onto the AC. Achieving equilibration of PCBs onto the powdered activated carbon (PAC) was accomplished in days to weeks, but granular activated carbon (GAC) uptake was not complete for some high molecular weight congeners in a year. The data were used to fit linear driving force models with both linear and Freundlich models of equilibrium. The models were then used to predict uptake onto powdered and granular AC during in-situ capping and treatment using the CapSim model. Slow kinetics can significantly limit the performance of granular AC in high upwelling (> 1-10 cm/day) environments. This study demonstrates the usage of polymeric passive samplers to explore sorption kinetics and equilibrium for low solubility compounds as well as the differences in performance of granular and powdered forms of AC for remediation of PCB contaminated sediment.

Corticosteroid Injections Into Lumbar Facet Joints: A Prospective, Randomized, Double-Blind Placebo-Controlled Trial.

BACKGROUND: Corticosteroid injections into the intra-articular zygapophysial (z-joints) are frequently used to treat this cause of low back pain. No studies have been done on the efficacy of intra-articular corticosteroids in those with z-joint pain confirmed by dual comparative medial branch blocks. OBJECTIVE: The aim of the study was to determine whether an injection of a corticosteroid into lumbar z-joints is effective in reducing pain and the need for radiofrequency neurotomy. METHODS: This is a double-blind, prospective, randomized, placebo-controlled trial. The study was conducted in Academic Medical Center. Twenty-eight subjects with z-joint pain confirmed by medial branch blocks were included in the study. Subjects with confirmed z-joint pain via dual comparative medial branch block were randomized to receive either intra-articular corticosteroid (triamcinolone 20 mg) or saline via fluoroscopic guided injection. RESULTS: No statistically significant difference in the need for radiofrequency neurotomy (radiofrequency neurotomy) between the groups, with 75% (95% confidence interval = 50.5%-99.5%) of the saline group vs. 91% (95% confidence interval = 62.3%-100%) of the corticosteroid group receiving radiofrequency neurotomy. There is no difference in mean time to radiofrequency neurotomy between saline (6.1 wks) and corticosteroid (6.5 wks) groups. There is a need for radiofrequency neurotomy. CONCLUSIONS: Corticosteroid injections into the lumbar z-joints were not effective in reducing the need for radiofrequency neurotomy of the medial branches in those with z-joint pain confirmed by dual comparative medial branch blocks.

Putting the t in tools: a roadmap for implementation of new global and regional transgender guidance.

Transgender (trans) activists and global health partners have collaborated to develop new tools and guidance for assessing and addressing HIV and other health needs within trans populations. Trans women experience a heavy burden of HIV and other sexually transmitted infections (STIs), high incidence of violence and difficulties accessing gender-affirming services. At the same time, little has been published on trans men's health, HIV issues, needs and experiences. Young trans people are especially marginalized and vulnerable, with few programmes and services specifically tailored to their needs. Trans-specific data and guidance are needed to adapt the global response to HIV to meet the needs of the trans population. While the needs of this group have only recently received attention, global, regional and other technical guidance documents are being developed to address these gaps. Regional blueprints for comprehensive care for trans people in Latin America, the Caribbean, and Asia and the Pacific are now available. These tools - supported by the Pan American Health Organization, World Health Organization, US President's Emergency Plan for AIDS Relief and the United Nations Development Programme, in collaboration with regional trans groups - provide a contextual map, indicating opportunities for interventions in health, HIV, violence, stigma and discrimination, social protection and human rights. Global guidance includes the World Health Organization's Policy Brief: Transgender People and HIV, and the interagency publication, Implementing Comprehensive HIV and STI Programmes with Transgender People. Community empowerment and capacity building are the focus of the new tools for global and regional transgender guidance. The goal is to strengthen and ensure community-led responses to the HIV challenge in trans populations. This article describes the new tools and guidance and considers the steps needed to use them to appropriately support and engage transgender populations within national AIDS, STI, and sexual and reproductive health responses and programmes. The time to use these tools and guidance for advocacy, strategic planning, capacity building, programme design and training is now.

Cardiomyocyte apoptosis contributes to pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated mice.

Cirrhotic cardiomyopathy is defined as systolic and diastolic dysfunctions, electrophysiological changes and macroscopic structural changes. However, the underlying mechanisms of this syndrome remain unclear. A possible role of myocardial apoptosis in the pathogenesis has not been previously examined. We hypothesized that dysregulation of apoptotic signalling participates in cardiac dysfunction in the cirrhotic heart. Therefore, we evaluated apoptotic pathways in the hearts of mice with chronic BDL (bile duct ligation). A cirrhotic cardiomyopathy model was induced by BDL in mice. Left ventricular geometry and volumes were evaluated by MRI. Intrinsic and extrinsic apoptotic pathways were evaluated by immunohistochemical staining and Western blot analysis. Fas-mediated apoptosis was inhibited by in vivo administration of an anti-FasL (Fas ligand) monoclonal antibody, and subsequently cardiac contractility was measured in isolated cardiomyocytes. BDL-mice showed significantly more PARP [poly(ADP-ribose) polymerase] staining than sham controls (18.2±11.4 compared with 6.7±5.3; P<0.05). Fas protein expression and PARP cleavage were activated, whereas FLIP (Fas-associated death domain-like interleukin 1ß-converting enzyme-inhibitory protein) was decreased compared with sham controls. The Bcl-2/Bax ratio was increased in BDL-mice compared with sham controls. Anti-FasL monoclonal antibody injection in BDL-mice improved systolic and diastolic dysfunctions in cardiomyocytes, but had no effect in sham controls. A net pro-apoptotic balance exists in BDL hearts, mainly mediated by activation of the extrinsic pathway, and abrogation of apoptosis improved contractility. These results suggest that apoptosis contributes to depressed cardiac contractility in a murine model of cirrhotic cardiomyopathy.

Analysis of organic nitrogen removal in municipal wastewater by reverse osmosis.

The results of a pilot study that was conducted to determine the total nitrogen removal by the reverse osmosis process are presented. The organic nitrogen removal rates are compared with removals observed from three full-scale reverse osmosis facilities and four pilot studies. The results of this analysis suggest that organic nitrogen removal is variable and that reverse osmosis may not consistently produce total nitrogen levels less than 1.0 mg/L without additional treatment. Three hypotheses to explain the variability in organic nitrogen removal in the different data sets are presented.

Combustion front dynamics in the combustion synthesis of refractory metal carbides and di-borides using time-resolved X-ray diffraction.

A compact diffraction-reaction chamber, using a 2-inch photodiode array detector, has been employed to investigate the chemical dynamics at the combustion front of a selected series of refractory metal carbides and di-borides from their constituent element reactants as well as binary products from B4C as a reactant. These systems are denoted as (i) M + C --> MC; (ii) M + 2B --> MB2; and (iii) 3M + B4C --> 2MB2 + MC, where M = Ti, Zr, Nb, Hf or Ta. Time-resolved X-ray diffraction using intense synchrotron radiation at frame rates up to 10 frames s(-1) (or 100 ms frame(-1)) was employed. The combustion reactions were found to complete within 200-400 ms. In contrast to the Ta + C --> TaC combustion system studied earlier, in which a discernible intermediate sub-carbide phase was first formed, reacted further and disappeared to yield the final TaC product, no intermediate sub-carbide or sub-boride was detected in the current systems. Combustion for the Ti, Zr and Hf systems involved a liquid phase, in which the adiabatic temperatures Tad are well above the melting points of the respective reactant metals and have a typical combustion front velocity of 5-6 mm s(-1). The Nb and Ta systems have lower Tad, involving no liquid phase. These are truly solid combustion systems and have a lower combustion front velocity of 1-2 mm s(-1). The current study opens up a new avenue to chemical dynamics and macrokinetic investigations of high-temperature solid-state reactions.

Fear of severe acute respiratory syndrome (SARS) among health care workers.

In this study, the authors examined fear related to severe acute respiratory syndrome (SARS) among 2 samples of hospital staff in Hong Kong. Sample 1 included health care workers (n=82) and was assessed during the peak of the SARS epidemic. Sample 2 included hospital staff who recovered from SARS (n=97). The results show that participants in both samples had equal, if not more, concern about infecting others (especially family members) than being self-infected. Sample 1 participants had stronger fear related to infection than Sample 2 participants, who seemed to be concerned more about other health problems and discrimination. Participants with lower self-efficacy tended to have higher fear related to SARS. Fear related to SARS was also correlated positively with posttraumatic stress symptoms among respondents of Sample 2 (recovered staff). Interventions based on these findings are described.

Phonon dispersions of fcc delta-plutonium-gallium by inelastic x-ray scattering.

We report an experimental determination of the phonon dispersion curves in a face-centered cubic (fcc) delta-plutonium-0.6 weight % gallium alloy. Several unusual features, including a large elastic anisotropy, a small-shear elastic modulus C', a Kohn-like anomaly in the T1[011] branch, and a pronounced softening of the [111] transverse modes, are found. These features can be related to the phase transitions of plutonium and to strong coupling between the lattice structure and the 5f valence instabilities. Our results also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory calculations for delta-plutonium.

Ultraviolet protection factors for clothing: an intercomparison of measurement systems.

In recent years the need to standardize measurement protocols for quantifying the degree of ultraviolet radiation (UVR) protection provided by clothing has led to the introduction of a number of standards around the world. To date, these standards have specified spectral measurements of UVR transmission by clothing and fabrics. Development of a standard test method has become an important part of the testing process, and this article presents results from an intercomparison involving 10 independent testing laboratories and 11 different UVR transmission measurement instruments. In addition to comparing the measured ultraviolet protection factors (UPF), this intercomparison also incorporates detailed scan results from all 10 laboratories and highlights differences in performance of the various instruments in different wavelength regions. Careful examination of these differences can indicate where changes to the systems could be made to allow improvements both in equipment performance and in agreement of the final results. The variability in the measurements of UPF in this study suggest that the protection categories in standards may need to be broadened.

Dynamics of phase transformations and microstructure evolution in carbon-manganese steel arc welds using time-resolved synchrotron X-ray diffraction.

Phase transformations that occur in both the heat-affected zone (HAZ) and the fusion zone (FZ) of a carbon-manganese steel spot weld have been investigated using time-resolved X-ray diffraction (TRXRD) with time resolutions down to 50 ms. It is found that in both zones the gamma(f.c.c.) --> alpha(b.c.c.) transformation on cooling is twice as fast as the forward transformation of alpha --> gamma on heating. Profile analysis of the major Bragg reflections recorded in the TRXRD patterns reveals similarities and differences in the microstructural evolution with time in the HAZ and in the FZ. The latter undergoes melting and solidification in addition to solid-state transformations. With increasing temperature, the (110) d-spacing of the alpha phase prior to and during the alpha --> gamma transformation and the (111) d-spacing of the gamma phase just after the same transformation exhibit a decrease. The observed (and unusual) lattice contraction with temperature rise may be attributed to chemical effects, such as carbide precipitation in the alpha matrix, and/or mechanical effects due to stress relief. In the FZ, the gamma-Fe that forms has a preferential (200) texture on solidification of the liquid, whereas, on cooling in the HAZ, the gamma-Fe retains largely a (111) texture that is induced in the alpha --> gamma transformation on heating. On cooling in the HAZ, the width of the gamma(111) reflection increases initially, which is indicative of microstrain developing in the f.c.c. lattice, but decreases as expected, with a reduction of thermal disorder, on further cooling until the completion of the gamma --> alpha transformation. In the FZ, however, the microstrain in the gamma phase increases steadily on solidification and more rapidly for the duration of the gamma --> alpha transformation on further cooling. The final microstructure of the FZ is likely to consist of a single alpha phase dispersed in two morphological entities, whereas in the HAZ the alpha phase persists in one morphological entity in the final microstructure.