Ammonia decomposition over cobalt/carbon catalysts—Effect of carbon support and electron donating promoter on activity

This paper sets the new design parameters for the development of low temperature ammonia decomposition catalysts based on readily available cobalt as an alternative to scarce but highly active ruthenium-based catalysts. By using a variety of carbon materials as catalytic supports, we systematically demonstrate that microporous supports capable of stabilising small cobalt crystallites (~2 nm) lead to high catalytic activities compared to bigger nanoparticles. Additionally, the degree of graphitisation of the carbon support has a detrimental effect on the activity of the cobalt (0) active sites, likely due to their potential as an electron donator. Consequently, the addition of electron donating promoters such as cesium substantially decreases the activity of the cobalt catalysts. This relationship deviates from the trends observed for ruthenium-based catalysts with an optimum 3–5 nm size where an increase of the graphitisation degree of the support and the addition of electron donating promoters increases the ammonia decomposition activity.The authors would like to acknowledge the UK Engineering and Physical Science Research Council (grant number EP/L020432/2) and the Doctoral Training Centre in the Centre for Sustainable Chemical Technologies at the University of Bath (grant number EP/K016334/1) for funding, and SASOL UK Ltd for supporting TEB’s studentship. We would also like to thank the Research Catalysis Group at Harwell(RCaH)for access to the TEM microscopy facilities.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.cattod.2016.05.04

The androgen receptor drives the sex-specific expression of vascular cell adhesion molecule-1 in endothelial cells but not lipid metabolism genes in monocyte-derived macrophages

Background: Anecdotal evidence suggests that male sex hormones are proatherogenic. We hypothesized that the male sex hormone receptor, the androgen receptor (AR), acts as a molecular switch in sex-specific inflammatory signaling in vascular cells. Materials and methods: AR expression in human umbilical vein endothelial cells (HUVECs), human monocyte-derived macrophages (MDMs) or HeLa cells was modulated by transfection with AR siRNA or human AR cDNA expression vector. Activity and expression levels were measured by luciferase reporter assays, Western blotting or real-time PCR analysis. Results: AR knockdown reduced expression of vascular cell adhesion molecule-1 (VCAM-1) in genetically male HUVECs. Conversely, AR upregulation in genetically female HUVECs induced VCAM-1 expression and increased dihydrotestos-terone-stimulated monocyte adhesion. Co-transfection of an AR expression vector with VCAM-1 or NF-kB-reporter vectors into phenotypically female, AR-negative HeLa cells confirmed AR regulation of VCAM-1 expression as well as AR activation of NF-kB. AR upregulation was not sufficient to increase ICAM-1 levels in female HUVECs or lipoprotein metabolism gene expression in female MDMs, despite AR knockdown limiting expression in their male counterparts. Conclusions: AR acts as a molecular switch to induce VCAM-1 expression. Low AR levels in female HUVECs limit NF-kB/VCAM-1 induction and monocyte adhesion and could contribute to the gender bias in cardiovascular disease. Unidentified factors in female cells limit induction of other proatherogenic genes not primarily regulated by NF-kB. © 2010, by Walter de Gruyter Berlin New York. All rights reserved

Correction: Detecting antimicrobial resistance in Escherichia coli using benchtop attenuated total reflectance-Fourier transform infrared spectroscopy and machine learning.

Correction for 'Detecting antimicrobial resistance in Escherichia coli using benchtop attenuated total reflectance-Fourier transform infrared spectroscopy and machine learning' by Hewa G. S. Wijesinghe et al., Analyst, 2021, DOI: 10.1039/d1an00546d

High-RI resist polymers for 193 nm immersion lithography

A critical aim within the field of 193 nm immersion lithography is the development of high refractive index immersion fluids and resists. Increases in the refractive index (RI) of the immersion fluid will result in increases in the numerical aperture and depth of focus. Increasing the RI of resist polymers will improve exposure latitude for the process. A challenge for increasing the RI of resist polymers is to do so without detrimentally affecting other properties of the polymer such as transparency, line edge roughness, adhesion and plasma etch resistance. It is well known in the literature that introducing sulfur, bromine or aromatic groups into a polymer structure will increase its RI. However, due to the relatively strong absorption of phenyl groups at 193 nm these groups have to be avoided. Furthermore, the use of bromine poses problems associated with contamination of the silicon wafer. Hence, in this study, a systematic approach has been used to increase the sulfur content of 193 nm type resist polymers, by synthesis of sulfur-containing monomers and by performing bulk modifications of the polymer. The effect of sulfur content on the RI at 193 nm was then investigated. A broad study of the relationship between molecular structure and RI dispersion from 250-180 nm has also been undertaken, and conclusions drawn using QSPR methodologies. Finally, the effect of sulfur content on other lithography parameters, such as transparency, adhesion and plasma etch resistance, was also evaluated

Synthesis of high-refractive index sulfur containing polymers for 193-nm immersion lithography: A progress report

To be able to extend the 193 nm immersion lithography technology platform, the development of high refractive index immersion fluids and resists is required. This paper reports our investigations into generating high refractive index polymers for use in photoresist formulations for 193 nm immersion lithograph. In this study a series of model compounds have been screened for refractive index and transparency at 589 nm and 193 nm. For the compounds studied this series of experiments demonstrated that sulfur-containing compounds have a positive effect on the refractive index of a molecule at 589 nm. However, the situation is complicated by the presence of absorption bands for some small molecules in the low waveleingth region. To demonstrate this, we examined the refractive index dispersion of a series of molecules based on ethyl acetate with varying degrees of sulfur substitution. These results indicated that an anomalous increase in refractive index could be expected 20 - 30 nm above the absorption maximum. The implications for design of high refractive index resists for 193 nm immersion lithography are discussed

“Quality teaches you how to use water. It doesn’t provide a water pump”: a qualitative study of context and mechanisms of action in an Ethiopian quality improvement program

Background Quality improvement collaboratives are a common approach to bridging the quality-of-care gap, but little is known about implementation in low-income settings. Implementers rarely consider mechanisms of change or the role of context, which may explain collaboratives’ varied impacts. Methods To understand mechanisms and contextual influences we conducted 55 in-depth interviews with staff from four health centres and two hospitals involved in quality improvement collaboratives in Ethiopia. We also generated control charts for selected indicators to explore any impacts of the collaboratives. Results The cross facility learning sessions increased the prominence and focus on quality, allowed learning from experts and peers and were motivational through public recognition of success or a desire to emulate peers. Within facilities, new structures and processes were created. These were fragile and sometimes alienating to those outside the improvement team. The trusted and respected mentors were important for support, motivation and accountability. Where mentor visits were infrequent or mentors less skilled, team function was impacted. These mechanisms were more prominent, and quality improvement more functional, in facilities with strong leadership and pre-existing good teamwork; as staff had shared goals, an active approach to problems and were more willing and able to be flexible to implement change ideas. Quality improvement structures and processes were more likely to be internally driven and knowledge transferred to other staff in these facilities, which reduced the impact of staff turnover and increased buy-in. In facilities which lacked essential inputs, staff struggled to see how the collaborative could meaningfully improve quality and were less likely to have functioning quality improvement. The unexpected civil unrest in one region strongly disrupted the health system and the collaborative. These contextual issues were fluid, with multiple interactions and linkages. Conclusions The study confirms the need to carefully consider context in the implementation of quality improvement collaboratives. Facilities that implement quality improvement successfully may be those that already have characteristics that foster quality. Quality improvement may be alienating to those outside of the improvement team and implementers should not assume the organic spread or transfer of quality improvement knowledge

The Mechanical Behavior of a 25Cr Super Duplex Stainless Steel at Elevated Temperature

Peer reviewedPostprin

PGB pair production at LHC and ILC as a probe of the topcolor-assisted technicolor models

The topcolor-assisted technicolor (TC2) model predicts some light pseudo goldstone bosons (PGBs), which may be accessible at the LHC or ILC. In this work we study the pair productions of the charged or neutral PGBs at the LHC and ILC. For the productions at the LHC we consider the processes proceeding through gluon-gluon fusion and quark-antiquark annihilation, while for the productions at the ILC we consider both the electron-positron collision and the photon-photon collision. We find that in a large part of parameter space the production cross sections at both colliders can be quite large compared with the low standard model backgrounds. Therefore, in future experiments these productions may be detectable and allow for probing TC2 model.Comment: 26 pages, 16 figures. slight changes in the text; notations for curves changed; references adde

Strong control of Southern Ocean cloud reflectivity by ice-nucleating particles

Large biases in climate model simulations of cloud radiative properties over the Southern Ocean cause large errors in modeled sea surface temperatures, atmospheric circulation, and climate sensitivity. Here, we combine cloud-resolving model simulations with estimates of the concentration of ice-nucleating particles in this region to show that our simulated Southern Ocean clouds reflect far more radiation than predicted by global models, in agreement with satellite observations. Specifically, we show that the clouds that are most sensitive to the concentration of ice-nucleating particles are low-level mixed-phase clouds in the cold sectors of extratropical cyclones, which have previously been identified as a main contributor to the Southern Ocean radiation bias. The very low ice-nucleating particle concentrations that prevail over the Southern Ocean strongly suppress cloud droplet freezing, reduce precipitation, and enhance cloud reflectivity. The results help explain why a strong radiation bias occurs mainly in this remote region away from major sources of ice-nucleating particles. The results present a substantial challenge to climate models to be able to simulate realistic ice-nucleating particle concentrations and their effects under specific meteorological conditions

Women's Experiences and Views about Costs of Seeking Malaria Chemoprevention and other Antenatal Services: A Qualitative Study from two Districts in Rural Tanzania.

The Tanzanian government recommends women who attend antenatal care (ANC) clinics to accept receiving intermittent preventive treatment against malaria during pregnancy (IPTp) and vouchers for insecticide-treated nets (ITNs) at subsidized prices. Little emphasis has been paid to investigate the ability of pregnant women to access and effectively utilize these services. To describe the experience and perceptions of pregnant women about costs and cost barriers for accessing ANC services with emphasis on IPTp in rural Tanzania. Qualitative data were collected in the districts of Mufindi in Iringa Region and Mkuranga in Coast Region through 1) focus group discussions (FGDs) with pregnant women and mothers to infants and 2) exit-interviews with pregnant women identified at ANC clinics. Data were analyzed manually using qualitative content analysis methodology. FGD participants and interview respondents identified the following key limiting factors for women's use of ANC services: 1) costs in terms of money and time associated with accessing ANC clinics, 2) the presence of more or less official user-fees for some services within the ANC package, and 3) service providers' application of fines, penalties and blame when failing to adhere to service schedules. Interestingly, the time associated with travelling long distances to ANC clinics and ITN retailers and with waiting for services at clinic-level was a major factor of discouragement in the health seeking behaviour of pregnant women because it seriously affected their domestic responsibilities. A variety of resource-related factors were shown to affect the health seeking behaviour of pregnant women in rural Tanzania. Thus, accessibility to ANC services was hampered by direct and indirect costs, travel distances and waiting time. Strengthening of user-fee exemption practices and bringing services closer to the users, for example by promoting community-directed control of selected public health services, including IPTp, are urgently needed measures for increasing equity in health services in Tanzania