Synergizing Fe2O3 nanoparticles on single atom Fe-N-C for nitrate reduction to ammonia at industrial current densities.

The electrochemical reduction of oxidized nitrogen species enables a pathway for the carbon neutral synthesis of ammonia (NH3). The most oxidized form of nitrogen, nitrate (NO3 -) can be reduced to NH3 via the electrocatalytic nitrate reduction reaction (NO3RR), which has been demonstrated at high selectivity. However, to make NH3 synthesis cost-competitive with current technologies, high NH3 partial current densities (jNH3) must be achieved to reduce the levelized cost of NH3. Here, we leverage the high NO3RR activity of Fe-based materials to synthesize a novel active particle-active support system with Fe2O3 nanoparticles supported on atomically dispersed Fe-N-C. By synergizing the activity of both nanoparticles and single atom sites, the optimized 3xFe2O3/Fe-N-C catalyst demonstrates an ultrahigh NO3RR activity, reaching a maximum jNH3 of 1.95 A cm-2 at a Faradaic efficiency (FE) for NH3 of 100% and an NH3 yield rate over 9 mmol hr-1 cm-2 (at -1.2 V versus RHE). In-situ XANES and post-mortem XPS reveal the importance of a pre-reduction activation step, reducing the surface Fe2O3 (Fe3+) to highly active Fe0 sites, which are maintained during electrolysis, to realize the ultrahigh NO3RR activity. Durability studies demonstrate the robustness of both the Fe2O3 particles and Fe-Nx sites at highly cathodic potentials, maintaining a current of -1.3 A cm-2 over 24 hours, a near unity FENH3 (at -1.0 V versus RHE). This work exhibits an effective and durable active particle-active support system enhancing the performance of the NO3RR, enabling industrially relevant current densities and near 100% selectivity. This article is protected by copyright. All rights reserved.

Chemical Kinetic Method for Active-Site Quantification in Fe-N-C Catalysts and Correlation with Molecular Probe and Spectroscopic Site-Counting Methods.

Mononuclear Fe ions ligated by nitrogen (FeNx) dispersed on nitrogen-doped carbon (Fe-N-C) serve as active centers for electrocatalytic O2 reduction and thermocatalytic aerobic oxidations. Despite their promise as replacements for precious metals in a variety of practical applications, such as fuel cells, the discovery of new Fe-N-C catalysts has relied primarily on empirical approaches. In this context, the development of quantitative structure-reactivity relationships and benchmarking of catalysts prepared by different synthetic routes and by different laboratories would be facilitated by the broader adoption of methods to quantify atomically dispersed FeNx active centers. In this study, we develop a kinetic probe reaction method that uses the aerobic oxidation of a model hydroquinone substrate to quantify the density of FeNx centers in Fe-N-C catalysts. The kinetic method is compared with low-temperature Mössbauer spectroscopy, CO pulse chemisorption, and electrochemical reductive stripping of NO derived from NO2- on a suite of Fe-N-C catalysts prepared by diverse routes and featuring either the exclusive presence of Fe as FeNx sites or the coexistence of aggregated Fe species in addition to FeNx. The FeNx site densities derived from the kinetic method correlate well with those obtained from CO pulse chemisorption and Mössbauer spectroscopy. The broad survey of Fe-N-C materials also reveals the presence of outliers and challenges associated with each site quantification approach. The kinetic method developed here does not require pretreatments that may alter active-site distributions or specialized equipment beyond reaction vessels and standard analytical instrumentation.

Elucidating electrochemical nitrate and nitrite reduction over atomically-dispersed transition metal sites.

Electrocatalytic reduction of waste nitrates (NO3-) enables the synthesis of ammonia (NH3) in a carbon neutral and decentralized manner. Atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts demonstrate a high catalytic activity and uniquely favor mono-nitrogen products. However, the reaction fundamentals remain largely underexplored. Herein, we report a set of 14; 3d-, 4d-, 5d- and f-block M-N-C catalysts. The selectivity and activity of NO3- reduction to NH3 in neutral media, with a specific focus on deciphering the role of the NO2- intermediate in the reaction cascade, reveals strong correlations (R=0.9) between the NO2- reduction activity and NO3- reduction selectivity for NH3. Moreover, theoretical computations reveal the associative/dissociative adsorption pathways for NO2- evolution, over the normal M-N4 sites and their oxo-form (O-M-N4) for oxyphilic metals. This work provides a platform for designing multi-element NO3RR cascades with single-atom sites or their hybridization with extended catalytic surfaces.

Innovations, adaptations, and accelerations in the delivery of HIV services during COVID-19.

During 2020, the COVID-19 pandemic disrupted the delivery of HIV prevention and treatment services globally. To mitigate the negative consequences of the pandemic, service providers and communities adapted and accelerated an array of HIV interventions to meet the needs of people living with HIV and people at risk of acquiring HIV in diverse geographical and epidemiological settings. As a result of these adaptations, services such as HIV treatment showed programmatic resilience and remained relatively stable in 2020 and into the first half of 2021. To review lessons learned and suggest which novel approaches to sustain, UNAIDS convened a virtual consultation on Feb 1-2, 2022, which was attended by a range of stakeholders from different areas of global HIV response.

Protocol for rapid ammonia detection via surface-enhanced Raman spectroscopy.

As a key industrial nitrogenous product and a critical environmental pollutant, ammonia broadly affects our daily lives. Rapid and sensitive detection of ammonia is essential to both environmental monitoring and process control for industrial manufacturing. Here, we present a protocol for rapid detection of low amounts of ammonia in the aqueous phase, via surface-enhanced Raman spectroscopy. We believe the mechanism and speed of the approach demonstrate its potential toward applications in operando electrochemical catalysis and in situ ammonia detection. For complete details on the use and execution of this protocol, please refer to Liu et al. (2020).

What will it take to end AIDS in Asia and the Pacific region by 2030?

The 2016 global commitments towards ending the AIDS epidemic by 2030 require the Asia-Pacific region to reach the Fast-Track targets by 2020. Despite early successes, the region is well short of meeting these targets. The overall stalled progress in the HIV response has been further undermined by rising new infections among young key populations and the unprecedented COVID-19 pandemic. This paper examines the HIV situation, assesses the gaps, and analyses what it would take the region to end AIDS by 2030. Political will and commitments for ending AIDS must be reaffirmed and reinforced. Focused regional strategic direction that answers the specific regional context and guides countries to respond to their specific needs must be put in place. The region must harness the power of innovative tools and technology in both prevention and treatment. Community activism and meaningful community engagement across the spectrum of HIV response must be ensured. Punitive laws, stigma, and discrimination that deter key populations and people living with HIV from accessing health services must be effectively tackled. The people-centred public health approach must be fully integrated into national universal health coverage while ensuring domestic resources are available for community-led service delivery. The region must utilise its full potential and draw upon lessons that have been learnt to address common challenges of the HIV and COVID-19 pandemics and achieve the goal of ending AIDS by 2030, in fulfillment of the United Nations' Sustainable Development Goals.

Regulatory encoding of quantitative variation in spatial activity of a Drosophila enhancer.

Developmental enhancers control the expression of genes prefiguring morphological patterns. The activity of an enhancer varies among cells of a tissue, but collectively, expression levels in individual cells constitute a spatial pattern of gene expression. How the spatial and quantitative regulatory information is encoded in an enhancer sequence is elusive. To link spatial pattern and activity levels of an enhancer, we used systematic mutations of the yellow spot enhancer, active in developing Drosophila wings, and tested their effect in a reporter assay. Moreover, we developed an analytic framework based on the comprehensive quantification of spatial reporter activity. We show that the quantitative enhancer activity results from densely packed regulatory information along the sequence, and that a complex interplay between activators and multiple tiers of repressors carves the spatial pattern. Our results shed light on how an enhancer reads and integrates trans-regulatory landscape information to encode a spatial quantitative pattern.

Facile All-Optical Method for In Situ Detection of Low Amounts of Ammonia.

As a key precursor for nitrogenous compounds and fertilizer, ammonia affects our lives in numerous ways. Rapid and sensitive detection of ammonia is essential, both in environmental monitoring and in process control for industrial production. Here we report a novel and nonperturbative method that allows rapid detection of ammonia at low concentrations, based on the all-optical detection of surface-enhanced Raman signals. We show that this simple and affordable approach enables ammonia probing at selected regions of interest with high spatial resolution, making in situ and operando observations possible.

Fast-tracking the end of HIV in the Asia Pacific region: domestic funding of key population-led and civil society organisations.

Ending AIDS in Asia Pacific by 2030 requires countries to give higher priority to financing community-based and key population-led service delivery. Mechanisms must be developed for civil society organisations to deliver health and HIV/AIDS services for key populations, especially men who have sex with men, and transgender people, within national health policy frameworks. Current investments in the HIV response in the Asia Pacific region reflect inadequate HIV financing for key populations, particularly for civil society and key population-led organisations that are optimally positioned to advance HIV epidemic control. These organisations are typically supported by international agencies whose investments are starting to decline. Domestic investments in key population-led organisations are often hampered by punitive laws against their communities, pervasive stigma and discrimination by policy makers, an insufficient understanding of the most effective HIV epidemic control strategies, and financing systems that limit access to funding for these organisations from the national budget. Countries in the Asia Pacific region are evolving their community-based and key population policies and programmes. We need accessible, disaggregated financial data and in-depth case studies that showcase effective key population-led programmes, to enable countries to learn from each other.

Evolution of the health sector response to HIV in Myanmar: progress, challenges and the way forward.

Critical building blocks for the response to HIV were made until 2012 despite a series of political, social and financial challenges. A rapid increase of HIV service coverage was observed from 2012 to 2015 through collaborative efforts of government and non-governmental organisations (NGOs). Government facilities, in particular, demonstrated their capacity to expand services for antiretroviral therapy (ART), prevention of mother-to-child transmission (PMTCT) of HIV, tuberculosis and HIV co-infection and methadone-maintenance therapy (MMT). After nearly three decades into the response to HIV, Myanmar has adopted strategies to provide the right interventions to the right people in the right places to maximise impact and cost efficiency. In particular, the country is now using strategic information to classify areas into high-, medium- and low-HIV burden and risk of new infections for geographical prioritisation - as HIV remains concentrated among key population (KP) groups in specific geographical areas. Ways forward include: •Addressing structural barriers for KP to access services, and identifying and targeting KPs at higher risk;•Strengthening the network of public facilities, NGOs and general practitioners and introducing a case management approach to assist KPs and other clients with unknown HIV status, HIV-negative clients and newly diagnosed clients to access the health services across the continuum to increase the number of people testing for HIV and to reduce loss to follow-up in both prevention and treatment;•Increasing the availability of HIV testing and counselling services for KPs, clients of female sex workers (FSW), and other populations at risk, and raising the demand for timely testing including expansion of outreach and client-initiated voluntary counselling and testing (VCT) services;•Monitoring and maximising retention from HIV diagnosis to ART initiation and expanding quality HIV laboratory services, especially viral load;•Prioritising integration of HIV and related services in high-burden areas;•Increasing the proportion of PLHIV receiving testing and treatment at public facilities by improving human resources and increasing public facilities providing these services to ensure sustainability;•Obtaining intelligence and tailoring services in hard-to-reach/under-served areas;•Strengthening planning, monitoring, and coordination capacity especially at regional levels.

Space-qualified laser system for the BepiColombo Laser Altimeter.

The space-qualified design of a miniaturized laser for pulsed operation at a wavelength of 1064 nm and at repetition rates up to 10 Hz is presented. This laser consists of a pair of diode-laser pumped, actively q-switched Nd:YAG rod oscillators hermetically sealed and encapsulated in an environment of dry synthetic air. The system delivers at least 300 million laser pulses with 50 mJ energy and 5 ns pulse width (FWHM). It will be launched in 2017 aboard European Space Agency's Mercury Planetary Orbiter as part of the BepiColombo Laser Altimeter, which, after a 6-years cruise, will start recording topographic data from orbital altitudes between 400 and 1500 km above Mercury's surface.

The Dublin cardiac arrest registry: temporal improvement in survival from out-of-hospital cardiac arrest reflects improved pre-hospital emergency care.

AIMS: Out-of-hospital cardiac arrest (OOHCA) survival remains poor, estimated at 3-7%. We aim to describe the incidence of OOHCA, survival from OOHCA, and the impact of improved pre-hospital care on survival from OOHCA. METHODS AND RESULTS: A retrospective registry was established using multi-source information to assess survival from cardiac arrest following the introduction of several improvements in pre-hospital emergency medical care from 2003. Survival from OOHCA, from asystole/pulseless electrical activity, and from ventricular tachycardia/ventricular fibrillation was estimated. Adjusted per 100 000 population annual incidence rates from national population census data were calculated. Mean and median emergency medical services (EMS) response times to OOHCA calls were assessed. A total of 962 OOHCAs occurred from 1 January 2003 until 31 December 2008. Sixty-nine per cent (69%, n = 664) were male. Seventy-two per cent (72%, n = 693) occurred at home with 28% occurring in a public venue. Of these public venues, 33.9% (91 of 268) had an automated external defibrillator available. Bystander cardiopulmonary resuscitation (CPR) was in progress when emergency services arrived in 11% (n = 106) of the cases. Nineteen per cent (19.4%, n = 187) had a known prior cardiac history or chest pain prior to circulatory collapse. Overall survival to hospital discharge improved significantly from 2.6 to 11.3%, P = 0.001. Survival from ventricular fibrillation (VF) to hospital admission, rose from 28.6 to 86.3%, P = 0.001. Survival to hospital discharge from VF improved from 21.4 to 33%, P = 0.007. Mean EMS response times to the scene of arrest decreased from 9.18 to 8.34 min. Emergency medical services scene time, reflecting acute pre-hospital medical care, rose from 14.46 to 18.12 min. The adjusted incidence of OOHCA for our catchment population declined from 109.4 to 88.2 per 100,000 population between 2003 and 2008. CONCLUSIONS: The incidence of OOHCA has declined but importantly, survival to hospital discharge has improved dramatically. Reduction in ambulance response time, resulting in earlier initiation of basic and advanced life support and earlier defibrillation, was associated with an increase in the proportion of victims found in VF rather than asystole and likely accounted for most of the improvement. Further improvements in response times and public education to improve bystander CPR rates should remain a priority.

Novel routes to Cu(salicylaldimine) covalently bound to silica: combined pulse EPR and in situ attenuated total reflection-IR studies of the immobilization.

Several novel routes for the immobilization of modified Cu(salicylaldimine) complexes on commercially available silica are described. New pulse electron paramagnetic resonance (EPR) and electron-nuclear double resonance sequences, which provide more detailed information than that available previously, in combination with continuous wave EPR, allow a definitive assignment of the geometry at the copper center in the immobilized Cu(salicylaldimine). Immobilization of the modified Cu(salicylaldimine) on silica was followed in situ by monitoring the intensity of the characteristic free- and metal-coordinated imine bands as a function of time using attenuated total reflectance IR spectroscopy. On the basis of these studies, the outcome of the Schiff base condensation of Cu-bis(salicylaldehyde) with gamma-aminopropyl-modified silica gel is shown to provide immobilized trans-O(2)N(2)- and O(3)N-coordinated immobilized Cu(salicylaldimine)-type compounds. In addition, trans-O(2)N(2)- or O(3)N-coordinated copper centers are selectively prepared on silica by controlling the aminopropyl modifier loading, thus opening a route to compounds not available by conventional synthesis. The O(3)N-coordinated Cu(salicylaldimine)-type compound on silica was investigated as a precursor for the synthesis of a tethered chiral Cu(salicylaldimine) via reaction of the coordinated carbonyl group with (R)-(+)-alpha-methylbenzylamine. Supported Cu(salicylaldimine) was also prepared via the immobilization of the appropriate silylethoxy-modified homogeneous precursor on silica gel. Precursors and silica-supported Cu(salicylaldimine) materials have been fully characterized. Comparisons are drawn with related Cu(salicylaldimine) immobilized in silica aerogels.

Evaluation and management of TMDs, Part 1. History, epidemiology, classification, anatomy, and patient evaluation.

The study of temporomandibular disorders has undergone many changes throughout its history. Focus on the structure and function of the TMJ continues to improve our understanding of these complex disorders. A more standardized classification system allows practitioners and researchers to discuss findings in a common language. With improved patient evaluation techniques, the clinician can establish a proper working differential diagnosis and begin focusing attention on treatment planning.

First Mixed Fluoro-Chloro Group 4 Organometallics: Synthesis and Spectroscopic and Structural Characterization of [{(C(5)Me(5))ZrF(2)Cl}(4)], [{(C(5)Me(5))HfF(2)Cl}(4)], [(C(5)Me(5))(4)Zr(4)(&mgr;-F)(2)(&mgr;-F(2))(2)(&mgr;-Cl)(2)Cl(4)], [(C(5)Me(5))(4)Hf(4)(&mgr;-F)(2)(&mgr;-F(2))(2)(&mgr;-Cl)(2)Cl(4)], [(C(5)Me(4)Et)(2)ZrClF], and [(C(5)Me(5))(2)HfClF].

Tetrameric [{(C(5)Me(5))MF(3)}(4)] (M = Zr, Hf) react smoothly with Me(3)SiCl in CH(2)Cl(2) at room temperature to give [{(C(5)Me(5))ZrF(2)Cl}(4)] (1) and [{(C(5)Me(5))HfF(2)Cl}(4)] (2), respectively, in high yield. Treatment of [{(C(5)Me(5))MF(3)}(4)] (M = Zr, Hf) with Me(2)AlCl in toluene gives mixtures of 1 and [(C(5)Me(5))(4)Zr(4)(&mgr;-F)(2)(&mgr;-F(2))(2)(&mgr;-Cl)(2)Cl(4)] (3), and 2 and [(C(5)Me(5))(4)Hf(4)(&mgr;-F)(2)(&mgr;-F(2))(2)(&mgr;-Cl)(2)Cl(4)] (4), respectively, in an approximately 1:1 molar ratio. Metallocene type complexes [(C(5)Me(4)Et)(2)ZrCl(2)] and [(C(5)Me(5))(2)HfCl(2)] react with 1 equiv of Me(3)SnF to give [(C(5)Me(4)Et)(2)ZrClF] (5) and [(C(5)Me(5))(2)HfClF] (6), respectively. The complexes 1-6 were characterized by spectroscopic methods ((1)H and (19)F NMR and mass spectroscopy). The solid state structures of 1, 3, and 5 were determined by single-crystal X-ray diffraction analyses.