NiP active site ensembles tune electrocatalytic nitrate reduction selectivity.

We demonstrate that active site ensembles on transition metal phosphides tune the selectivity of the nitrate reduction reaction. Using NiP nanocrystals as a case study, we report a mechanism involving competitive co-adsorption of H* and NO* intermediates. A near 100% faradaic efficiency for nitrate reduction over hydrogen evolution is observed at -0.

Phosphonate-based iron complex for a cost-effective and long cycling aqueous iron redox flow battery.

A promising metal-organic complex, iron (Fe)-NTMPA, consisting of Fe(III) chloride and nitrilotri-(methylphosphonic acid) (NTMPA), is designed for use in aqueous iron redox flow batteries. A full-cell testing, where a concentrated Fe-NTMPA anolyte (0.67 M) is paired with a Fe-CN catholyte, demonstrates exceptional cycling stability over 1000 charge/discharge cycles, and noteworthy performances, including 96% capacity utilization, a minimal capacity fade rate of 0.

Multilevel Computational Studies Reveal the Importance of Axial Ligand for Oxygen Reduction Reaction on Fe-N-C Materials.

The systematic improvement of Fe-N-C materials for fuel cell applications has proven challenging, due in part to an incomplete atomistic understanding of the oxygen reduction reaction (ORR) under electrochemical conditions. Herein, a multilevel computational approach, which combines ab initio molecular dynamics simulations and constant potential density functional theory calculations, is used to assess proton-coupled electron transfer (PCET) processes and adsorption thermodynamics of key ORR intermediates. These calculations indicate that the potential-limiting step for ORR on Fe-N-C materials is the formation of the Fe-OOH intermediate.

Understanding and tackling the activity and selectivity issues for methane to methanol using single atom alloys.

The process for the direct oxidation of methane to methanol is investigated on single atom alloys using density functional theory. A catalyst search is performed across FCC metal single atom alloys. 7 single atom alloys are found as candidates and microkinetic modelling is performed.

Hydrogen Coupling on Platinum Using Artificial Neural Network Potentials and DFT.

To date, the understanding of reactions at solid-liquid interfaces has proven challenging, mainly because of the inaccessible nature of such systems to current experimental techniques with atomic resolution. This has meant that many important features, including free energy barriers and the atomistic structure of intermediates, remain unknown. To tackle these issues, we construct and utilize a high-dimensional neural network (HDNN) potential for the simulation of hydrogen evolution at the HCl(aq)/Pt(111) interface, taking into consideration the influence of adsorbate-adsorbate, adsorbate-solvent interactions, and ion solvation explicitly.

Investigating the innate selectivity issues of methane to methanol: consideration of an aqueous environment.

The higher reactivity of the methanol product over the methane reactant for the direct oxidation of methane to methanol is explored. C-H activation, C-O coupling, and C-OH coupling are investigated as key steps in the selective oxidation of methane using DFT. These elementary steps are initially considered in the gas phase for a variety of fcc (111) pristine metal surfaces.

Understanding supported noble metal catalysts using first-principles calculations.

Heterogeneous catalysis on supported and nonsupported nanoparticles is of fundamental importance in the energy and chemical conversion industries. Rather than laboratory analysis, first-principles calculations give us an atomic-level understanding of the structure and reactivity of nanoparticles and supports, greatly reducing the efforts of screening and design. However, unlike catalysis on low index single crystalline surfaces, nanoparticle catalysis relies on the tandem properties of a support material as well as the metal cluster itself, often with charge transfer processes being of key importance.

Interconversion of hydrated protons at the interface between liquid water and platinum.

Hydrogen transfer is the fundamental step in electrochemistry involved in water splitting and the hydrogen evolution reaction (HER). However, the nature of this process at the solid-liquid interface has been little studied at the atomic level. In this work, we use ab initio molecular dynamics (AIMD) and umbrella sampling (US), giving us an accurate description of the dynamic processes associated with the solid-liquid environment.

Time-serial Assessment of Drug Combination Interventions in a Mouse Model of Colorectal Carcinogenesis Using Optical Coherence Tomography.

Optical coherence tomography (OCT) is a high-resolution, nondestructive imaging modality that enables time-serial assessment of adenoma development in the mouse model of colorectal cancer. In this study, OCT was utilized to evaluate the effectiveness of interventions with the experimental antitumor agent α-difluoromethylornithine (DFMO) and a nonsteroidal anti-inflammatory drug sulindac during early [chemoprevention (CP)] and late stages [chemotherapy (CT)] of colon tumorigenesis. Biological endpoints for drug interventions included OCT-generated tumor number and tumor burden.

Diagnostic potential of multimodal imaging of ovarian tissue using optical coherence tomography and second-harmonic generation microscopy.

Ovarian cancer is particularly deadly because it is usually diagnosed after it has metastasized. We have previously identified features of ovarian cancer using optical coherence tomography (OCT) and second-harmonic generation (SHG) microscopy (targeting collagen). OCT provides an image of the ovarian microstructure while SHG provides a high-resolution map of collagen fiber bundle arrangement.

In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis.

Background And Objective: Development of miniaturized imaging systems with molecular probes enables examination of molecular changes leading to initiation and progression of colorectal cancer in an azoxymethane (AOM)-induced mouse model of the disease. Through improved and novel studies of animal disease models, more effective diagnostic and treatment strategies may be developed for clinical translation. We introduce use of a miniaturized multimodal endoscope with lavage-delivered fluorescent probes to examine dynamic microenvironment changes in an AOM-treated mouse model.

Dual optical modality endoscopic imaging of cancer development in the mouse colon.

Background And Objective: We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon.

Materials And Methods: Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size.

Feasibility of optical coherence tomography imaging to characterize renal neoplasms: limitations in resolution and depth of penetration.

Unlabelled: What's known on the subject? and What does the study add? Optical coherence tomography has been used for the diagnosis of retinal disease and has been used experimentally for imaging of vascular plaques, gastrointestinal pathology, bladder cancer, prostate cancer, and recently to examine benign kidney microanatomy. It has not been previously used to image kidney cancer. This study presents the first data on the utility of OCT in the imaging for renal neoplasms.

Ultra-violet radiation is responsible for the differences in global epidemiology of chickenpox and the evolution of varicella-zoster virus as man migrated out of Africa.

Background: Of the eight human herpes viruses, varicella-zoster virus, which causes chickenpox and zoster, has a unique epidemiology. Primary infection is much less common in children in the tropics compared with temperate areas. This results in increased adult susceptibility causing outbreaks, for example in health-care workers migrating from tropical to temperate countries.

The advantages gained by the use of modern materials in the post operative casting procedure for foot and ankle surgery.

Background: In June 2006, the post operative plaster immobilisation protocol for patients undergoing hindfoot and ankle surgery, at our institution, changed from multiple plaster changes to the immediate application of a definitive removable and reusable split synthetic cast. This study aims to assess the savings to the hospital and patient, following this change in practice.

Methods: A retrospective analysis of plaster room records from June 2005 to June 2007 was performed.

DNA microarrays for virus detection in cases of central nervous system infection.

A low-density, high-resolution diagnostic DNA microarray comprising 38 gene targets for 13 viral causes of meningitis and encephalitis was constructed. The array has been used for the detection of multiplex PCR-amplified viruses in cerebrospinal fluid (CSF) and non-CSF specimens. A total of 41 clinical specimens were positive for echoviruses (23 samples), herpes simplex virus type 2 (4 samples), varicella-zoster virus (4 samples), human herpesvirus 7 (1 sample), human herpesvirus 6A (1 sample) and 6B (2 samples), Epstein-Barr virus (three samples), polyomavirus JC (1 sample), and cytomegalovirus (2 samples).

Early detection of cytomegalovirus (CMV) infection in bone marrow transplant patients by reverse transcription-PCR for CMV spliced late gene UL21.5: a two site evaluation.

Background: Bone marrow transplant (BMT) patients at risk of developing cytomegalovirus (CMV) pneumonitis are identified routinely by the early detection of virus in blood. For early diagnosis of CMV infection, the RNA-based approach demonstrates advantages when compared with the current CMV antigen and DNA detection methods.

Objectives: We have evaluated our previously developed reverse transcription-polymerase chain reaction (RT-PCR) to a spliced late CMV gene (SLG; J.

HIV seroprevalence by anonymous testing in patients with Mycobacterium tuberculosis and in tuberculosis contacts.

Having witnessed a large increase in Mycobacterium tuberculosis notifications in south London, we wanted to ascertain the prevalence of HIV and tuberculosis co-infection in our patients. All patients with tuberculosis and their contacts were anonymously tested for HIV in blood and saliva, respectively. 11.

High prevalence of human papillomavirus type 16 infection among children.

Infection with high-risk human papillomaviruses (HPV), is the most significant risk factor for cervical cancer and it may be possible to prevent this malignancy by immunisation. Before immunisation programmes can be designed, however, it is necessary to know the age of acquisition and all routes of infection for these viruses. Sexual transmission is well documented and vertical transmission has also been demonstrated, although the frequency of transmission remains controversial.

Testing for HIV antibodies should not be offered on a same-day basis.

Same-day testing for HIV is now offered in 16 of Genitourinary Medicine clinics in the UK and in 31 of those in London, and supposedly offers a reduction in client waiting time and anxiety levels. 'Same-day' is, however, misleading as the majority of same-day testing services provide same-day negative results only, with confirmed positive results being available no earlier than from a routine drop-in clinic. In addition, as most same-day testing services are appointment-based, patients would generally receive their results much sooner if they were to attend a drop-in clinic.

High risk genital papillomavirus infections are spread vertically.

It is well recognised that high-risk human papillomaviruses (HPVs) are spread by sexual activity, but the possibility of non-sexual transmission remains controversial. We present evidence for vertical transmission from at least 30% HPV positive mothers to their infants, resulting in persistent infection in children. That the mother is the source of infant infection has been confirmed by DNA sequencing.

Exposure to blood borne viruses and the hepatitis B vaccination status among healthcare workers in inner London.

Occupational exposure to blood borne viruses was examined during one year at a London teaching hospital. A total of 236 incidents occurred of which 83% were related to sharps, 32% were clearly avoidable, and 7% involved an infected source patient. Overall uptake of hepatitis B vaccine was 78% but it was particularly low in paramedical (70%) and domestic staff (45%).

A school outbreak of parvovirus B19 infection investigated using salivary antibody assays.

An outbreak of parvovirus B19 infection at a primary school was investigated using saliva samples. Antibody capture immunoassays for salivary B19 IgG and IgM were developed using a recombinant B19 antigen and monoclonal antibody to B19 virus. Evaluation of the salivary IgG assay using paired serum and saliva samples from 43 staff at St Thomas' Hospital showed that it had a sensitivity of 100% and a specificity of 95%.