A universal pH range and a highly efficient Mo2C-based electrocatalyst for the hydrogen evolution reaction

Electrochemical water splitting is a promising approach to generate ‘green’ hydrogen. The efficiency of this process relies on the effectiveness of the electrocatalysts used. The electro-kinetics of the hydrogen evolution reaction (HER) is highly pH dependent and conventional catalysts typically are expensive and rare platinum-based materials. The development of low-cost, multi-component electrocatalysts, where each of the components has a synergistic effect, can be an effective approach to improve kinetics. Herein, a series of transition metal (Fe, Mn, Co, and Ni)-modified molybdenum carbides in a nitrogen-doped carbon matrix (TM-Mo2C@NCF) are synthesised to maximise exposed active sites. Among them, Fe-Mo2C@NCF delivers the best-in-class HER performance over a wide range of electrolytes. Tafel slopes of 76, 109 and 110 mV dec−1 and overpotentials of 65, 130 and 129 mV at 10 mA cm−2 were obtained in 1.0 M KOH, 1.0 M phosphate buffer solution (PBS) and 0.5 M H2SO4, respectively. The computational study further indicates that the synergistic electronic modulation co-activated by Fe and N dopants in Fe-Mo2C@NCF can reduce the Gibbs free energy of H adsorption (ΔGH*) and render the Mo–Mo bridge site the most energetically favorable adsorption site for the H* intermediate, which contributes to an increased HER performance

Scheme for generating entangled states of two field modes in a cavity

This paper considers a two-level atom interacting with two cavity modes with equal frequencies. Applying a unitary transformation, the system reduces to the analytically solvable Jaynes-Cummings model. For some particular field states, coherent and squeezed states, the transformation between the two bare basis's, related by the unitary transformation, becomes particularly simple. It is shown how to generate, the highly non-classical, entangled coherent states of the two modes, both in the zero and large detuning cases. An advantage with the zero detuning case is that the preparation is deterministic and no atomic measurement is needed. For the large detuning situation a measurement is required, leaving the field in either of two orthogonal entangled coherent states.Comment: Accepted in J. Mod. Opt.; 12 pages; Replaced with revised version. Extended discussion of experimental realizations, earlier studies in the field and on the frequency dependence in the adiabatic eliminatio

Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals

We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson's stochastic approach to quantum mechanics, which we use to conceptually clarify the physical nature of part of the kinetic-energy functional in terms of statistical fluctuations and in direct correspondence with Fisher Information Theory. We show that the N-electron purely quantum kinetic energy can be written as the sum of the (one-electron) Weizsacker term and an (N-1)-electron kinetic correlation term. We further show that the Weizsacker term results from local fluctuations while the kinetic correlation term results from the nonlocal fluctuations. For one-electron orbitals (where kinetic correlation is neglected) we obtain an exact (albeit impractical) expression for the noninteracting kinetic energy as the sum of the classical kinetic energy and the Weizsacker term. The classical kinetic energy is seen to be explicitly dependent on the electron phase and this has implications for the development of accurate orbital-free kinetic-energy functionals. Also, there is a direct connection between the classical kinetic energy and the angular momentum and, across a row of the periodic table, the classical kinetic energy component of the noninteracting kinetic energy generally increases as Z increases.Comment: 10 pages, 1 figure. To appear in Theor Chem Ac

Use of multiple methods for genotyping Fusarium during an outbreak of contact lens associated fungal keratitis in Singapore

<p>Abstract</p> <p>Background</p> <p>In Singapore, an outbreak of fungal keratitis caused by members of the <it>Fusarium solani </it>species complex (FSSC) was identified in March 2005 to May 2006 involving 66 patients. Epidemiological investigations have indicated that improper contact lens wear and the use of specific contact lens solutions were risk factors.</p> <p>Methods</p> <p>We assessed the genetic diversity of the isolates using AFLP, Rep-PCR, and ERIC-PCR and compared the usefulness of these typing schemes to characterize the isolates.</p> <p>Results</p> <p>AFLP was the most discriminative typing scheme and appears to group FSSC from eye infections and from other infections differently.</p> <p>Conclusion</p> <p>There was a high genomic heterogeneity among the isolates confirming that this was not a point source outbreak.</p

What facilitates the delivery of dignified care to older people? A survey of health care professionals Geriatrics

Background: Whilst the past decade has seen a growing emphasis placed upon ensuring dignity in the care of older people this policy objective is not being consistently achieved and there appears a gap between policy and practice. We need to understand how dignified care for older people is understood and delivered by the health and social care workforce and how organisational structures and policies can promote and facilitate, or hinder, the delivery of such care. Methods: To achieve our objective of understanding the facilitators and to the delivery of dignified care we undertook a survey with health and social care professionals across four NHS Trusts in England. Participants were asked provide free text answers identifying any facilitators/barriers to the provision of dignified care. Survey data was entered into SPSSv15 and analysed using descriptive statistics. These data provided the overall context describing staff attitudes and beliefs about dignity and the provision of dignified care. Qualitative data from the survey were transcribed verbatim and categorised into themes using thematic analysis. Results: 192 respondents were included in the analysis. 79 % of respondents identified factors within their working environment that helped them provide dignified care and 68 % identified barriers to achieving this policy objective. Facilitators and barriers to delivering dignified care were categorised into three domains: 'organisational level'; 'ward level' and 'individual level'. Within the these levels, respondents reported factors that both supported and hindered dignity in care including 'time', 'staffing levels', training',' 'ward environment', 'staff attitudes', 'support', 'involving family/carers', and 'reflection'. Conclusion: Facilitators and barriers to the delivery of dignity as perceived by health and social care professionals are multi-faceted and range from practical issues to interpersonal and training needs. Thus interventions to support health and social care professionals in delivering dignified care, need to take a range of issues into account to ensure that older people receive a high standard of care in NHS Trusts.Professor David Oliver, Professor Andree le May, Dr. Sally Richards, Dr Wendy Marti

Hybridization in human evolution: Insights from other organisms

During the late Pleistocene, isolated lineages of hominins exchanged genes thus influencing genomic variation in humans in both the past and present. However, the dynamics of this genetic exchange and associated phenotypic consequences through time remain poorly understood. Gene exchange across divergent lineages can result in myriad outcomes arising from these dynamics and the environmental conditions under which it occurs. Here we draw from our collective research across various organisms, illustrating some of the ways in which gene exchange can structure genomic/phenotypic diversity within/among species. We present a range of examples relevant to questions about the evolution of hominins. These examples are not meant to be exhaustive, but rather illustrative of the diverse evolutionary causes/consequences of hybridization, highlighting potential drivers of human evolution in the context of hybridization including: influences on adaptive evolution, climate change, developmental systems, sex-differences in behavior, Haldane’s rule and the large X-effect, and transgressive phenotypic variation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151330/1/evan21787.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151330/2/evan21787_am.pd

XIAP impairs Smac release from the mitochondria during apoptosis

X-linked inhibitor of apoptosis protein (XIAP) is a potent inhibitor of caspases 3, 7 and 9, and mitochondrial Smac (second mitochondria-derived activator of caspase) release during apoptosis inhibits the activity of XIAP. In this study we show that cytosolic XIAP also feeds back to mitochondria to impair Smac release. We constructed a fluorescent XIAP-fusion protein by labelling NH2- and COOH-termini with Cerulean fluorescent protein (C-XIAP-C). Immunoprecipitation confirmed that C-XIAP-C retained the ability to interact with Smac and impaired extrinsically and intrinsically activated apoptosis in response to tumour necrosis factor-related apoptosis-inducing ligand/cycloheximide and staurosporine. In C-XIAP-C-expressing cells, cytochrome c release from mitochondria proceeded normally, whereas Smac release was significantly prolonged and incomplete. In addition, physiological expression of native XIAP prolonged or limited Smac release in HCT-116 colon cancer cells and primary mouse cortical neurons. The Smac-binding capacity of XIAP, but not caspase inhibition, was central for mitochondrial Smac retention, as evidenced in experiments using XIAP mutants that cannot bind to Smac or effector caspases. Similarly, the release of a Smac mutant that cannot bind to XIAP was not impaired by C-XIAP-C expression. Full Smac release could however be provoked by rapid cytosolic C-XIAP-C depletion upon digitonin-induced plasma membrane permeabilization. Our findings suggest that although mitochondria may already contain pores sufficient for cytochrome c release, elevated amounts of XIAP can selectively impair and limit the release of Smac

In situ Biological Dose Mapping Estimates the Radiation Burden Delivered to ‘Spared’ Tissue between Synchrotron X-Ray Microbeam Radiotherapy Tracks

Microbeam radiation therapy (MRT) using high doses of synchrotron X-rays can destroy tumours in animal models whilst causing little damage to normal tissues. Determining the spatial distribution of radiation doses delivered during MRT at a microscopic scale is a major challenge. Film and semiconductor dosimetry as well as Monte Carlo methods struggle to provide accurate estimates of dose profiles and peak-to-valley dose ratios at the position of the targeted and traversed tissues whose biological responses determine treatment outcome. The purpose of this study was to utilise γ-H2AX immunostaining as a biodosimetric tool that enables in situ biological dose mapping within an irradiated tissue to provide direct biological evidence for the scale of the radiation burden to ‘spared’ tissue regions between MRT tracks. Γ-H2AX analysis allowed microbeams to be traced and DNA damage foci to be quantified in valleys between beams following MRT treatment of fibroblast cultures and murine skin where foci yields per unit dose were approximately five-fold lower than in fibroblast cultures. Foci levels in cells located in valleys were compared with calibration curves using known broadbeam synchrotron X-ray doses to generate spatial dose profiles and calculate peak-to-valley dose ratios of 30–40 for cell cultures and approximately 60 for murine skin, consistent with the range obtained with conventional dosimetry methods. This biological dose mapping approach could find several applications both in optimising MRT or other radiotherapeutic treatments and in estimating localised doses following accidental radiation exposure using skin punch biopsies

Integrin CD11b positively regulates TLR4-induced signalling pathways in dendritic cells but not in macrophages.

Tuned and distinct responses of macrophages and dendritic cells to Toll-like receptor 4 (TLR4) activation induced by lipopolysaccharide (LPS) underpin the balance between innate and adaptive immunity. However, the molecule(s) that confer these cell-type-specific LPS-induced effects remain poorly understood. Here we report that the integrin α(M) (CD11b) positively regulates LPS-induced signalling pathways selectively in myeloid dendritic cells but not in macrophages. In dendritic cells, which express lower levels of CD14 and TLR4 than macrophages, CD11b promotes MyD88-dependent and MyD88-independent signalling pathways. In particular, in dendritic cells CD11b facilitates LPS-induced TLR4 endocytosis and is required for the subsequent signalling in the endosomes. Consistent with this, CD11b deficiency dampens dendritic cell-mediated TLR4-triggered responses in vivo leading to impaired T-cell activation. Thus, by modulating the trafficking and signalling functions of TLR4 in a cell-type-specific manner CD11b fine tunes the balance between adaptive and innate immune responses initiated by LPS

Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications