Gold nanocrystals with variable index facets as highly effective cathode catalysts for lithium-oxygen batteries

© 2015 Nature Publishing Group All rights reserved. Cathode catalysts are the key factor in improving the electrochemical performance of lithium-oxygen (Li-O2) batteries via their promotion of the oxygen reduction and oxygen evolution reactions (ORR and OER). Generally, the catalytic performance of nanocrystals (NCs) toward ORR and OER depends on both composition and shape. Herein, we report the synthesis of polyhedral Au NCs enclosed by a variety of index facets: cubic gold (Au) NCs enclosed by {100} facets; truncated octahedral Au NCs enclosed by {100} and {110} facets; and trisoctahedral (TOH) Au NCs enclosed by 24 high-index {441} facets, as effective cathode catalysts for Li-O2 batteries. All Au NCs can significantly reduce the charge potential and have high reversible capacities. In particular, TOH Au NC catalysts demonstrated the lowest charge-discharge overpotential and the highest capacity of ∼ 20 298 mA h g-1. The correlation between the different Au NC crystal planes and their electrochemical catalytic performances was revealed: high-index facets exhibit much higher catalytic activity than the low-index planes, as the high-index planes have a high surface energy because of their large density of atomic steps, ledges and kinks, which can provide a high density of reactive sites for catalytic reactions

Wasp-Waist Interactions in the North Sea Ecosystem

Background In a “wasp-waist” ecosystem, an intermediate trophic level is expected to control the abundance of predators through a bottom-up interaction and the abundance of prey through a top-down interaction. Previous studies suggest that the North Sea is mainly governed by bottom-up interactions driven by climate perturbations. However, few studies have investigated the importance of the intermediate trophic level occupied by small pelagic fishes. Methodology/Principal Findings We investigated the numeric interactions among 10 species of seabirds, two species of pelagic fish and four groups of zooplankton in the North Sea using decadal-scale databases. Linear models were used to relate the time series of zooplankton and seabirds to the time series of pelagic fish. Seabirds were positively related to herring (Clupea harengus), suggesting a bottom-up interaction. Two groups of zooplankton; Calanus helgolandicus and krill were negatively related to sprat (Sprattus sprattus) and herring respectively, suggesting top-down interactions. In addition, we found positive relationships among the zooplankton groups. Para/pseudocalanus was positively related to C. helgolandicus and C. finmarchicus was positively related to krill. Conclusion/Significance Our results indicate that herring was important in regulating the abundance of seabirds through a bottom-up interaction and that herring and sprat were important in regulating zooplankton through top-down interactions. We suggest that the positive relationships among zooplankton groups were due to selective foraging and switching in the two clupeid fishes. Our results suggest that “wasp-waist” interactions might be more important in the North Sea than previously anticipated. Fluctuations in the populations of pelagic fish due to harvesting and depletion of their predators might accordingly have profound consequences for ecosystem dynamics through trophic cascades

Biodiversity impacts of the 2019-2020 Australian megafires.

With large wildfires becoming more frequent1,2, we must rapidly learn how megafires impact biodiversity to prioritize mitigation and improve policy. A key challenge is to discover how interactions among fire-regime components, drought and land tenure shape wildfire impacts. The globally unprecedented3,4 2019-2020 Australian megafires burnt more than 10 million hectares5, prompting major investment in biodiversity monitoring. Collated data include responses of more than 2,000 taxa, providing an unparalleled opportunity to quantify how megafires affect biodiversity. We reveal that the largest effects on plants and animals were in areas with frequent or recent past fires and within extensively burnt areas. Areas burnt at high severity, outside protected areas or under extreme drought also had larger effects. The effects included declines and increases after fire, with the largest responses in rainforests and by mammals. Our results implicate species interactions, dispersal and extent of in situ survival as mechanisms underlying fire responses. Building wildfire resilience into these ecosystems depends on reducing fire recurrence, including with rapid wildfire suppression in areas frequently burnt. Defending wet ecosystems, expanding protected areas and considering localized drought could also contribute. While these countermeasures can help mitigate the impacts of more frequent megafires, reversing anthropogenic climate change remains the urgent broad-scale solution

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Distonias: aspectos terapêuticos

Diversas abordagens terapêuticas são utilizadas em pacientes com distonias. Sempre que possível, causas específicas devem ser identificadas e tratadas. As modalidades de tratamento sintomático podem ser agrupadas em três categorias: tratamento farmacológico, cirúrgico e injeções locais de toxina botulínica. Cada uma dessas modalidades apresenta algumas vantagens e limitações. Formas generalizadas, particularmente as de ocorrência na infância, podem se beneficiar com drogas anticolinérgicas ou, em alguns casos, com a levodopa ou outros agentes tais como antagonistas da dopamina, baclofeno e benzodiazepínicos. As formas focais não respondem adequadamente ao tratamento farmacológico sistêmico mas beneficiam-se significativamente com injeções de toxina botulínica nos grupos musculares acometidos. Cerca de 90% dos pacientes com blefarospasmo e 70% daqueles com distonia cervical apresentam resposta satisfatória a esse tipo de terapia. O tratamento cirúrgico tem sido utilizado em algumas formas de distonias generalizadas (lesões estereotáxicas), axiais (rizotomias) ou focais (miectomias e neurectomias) com resultados variáveis.Several approaches have been employed for the treatment of dystonias. Possible specific causes should be searched for and specific treatment should be instituted. Different types of symptomatic treatment are grouped according to the following categories: pharmacological systemic therapy, surgical therapy and botulinum toxin injections in the affected muscles. Each of these approaches has its advantages and limitations. Generalized dystonias should be treated with anticholinergic agents. In some cases, levodopa or other drugs such as dopamine antagonists, baclofen and benzodiazepines should be preferred. Focal dystonias respond dramatically to local injections of botulinum toxin. Over 90% of patients with blepharospasm and 70% of patients with cervical dystonia present a satisfactory response to this procedure. Surgical approaches have been utilized in some cases of generalized (stereotaxic lesions), axial (rhizotomies) and focal dystonias (myectomies and neurectomies) with variable results

Remotely Sensed Fire Heterogeneity and Biomass Recovery Predicts Empirical Biodiversity Responses

Aim: To compare field-based evidence of plant and animal responses to fire with remotely sensed signals of fire heterogeneity and post-fire biomass recovery. Location: South-eastern Australia; New South Wales. Time Period: 2019–2022. Major Taxa Studied: A total of 982 species of plants and animals, in eight taxonomic groups: amphibians, birds, fish, insects, mammals, molluscs, plants and reptiles. Methods: We collated 545,223 plant and animal response records from 47 field surveys of 4613 sites that focussed on areas burnt in 2019–2020. For each site, we calculated remotely sensed signals of fire heterogeneity and post-fire biomass recovery, including the delayed recovery index. Meta-regression analyses were conducted separately for species that declined after fire (negative effect sizes) and species that increased after fire (positive effect sizes) for each buffer size (250 m, 500 m, 1 km, 1.5 km, 2 km and 2.5 km radius). Results: We found that species exposed to homogenous high-severity fire (i.e., low fire heterogeneity) were more likely to exhibit decreased abundance/occurrence or inhibited recovery. Areas with delayed recovery of biomass also had significant negative on-ground responses, with lower abundance or occurrence in areas where biomass recovery was slower. Main Conclusions: The fire heterogeneity index and the delayed recovery index are suitable for inclusion in monitoring and reporting systems for tracking relative measures over time, particularly when field survey data is not available at the landscape scales required to support reporting and management decisions. Locations with remotely sensed signals of delayed recovery should be prioritised for protection against further disturbances that may interfere with the recovery process. Research attention must next focus on how cumulative fire heterogeneity patterns of successive fires affect the post-fire recovery dynamics to further inform the application of remote sensing indicators as management tools for biodiversity conservation

Risk factors for unpleasant paresthesiae induced by paresthesiae - producing deep brain stimulation Fatores de risco para parestesia dolorosa induzida por estimulação cerebral profuda em sítios produtores de parestesia

Paresthesiae-producing deep brain stimulation (stimulation of ventrocaudal nucleus - VC, medial lemniscus - ML or internal capsule - IC) is one of the few procedures to treat the steady element of neural injury pain (NIP) currently available. Reviewing the first 60 patients with NIP submitted to deep brain stimulation (DBS) from 1978 to 1991 at the Division of Neurosurgery, Toronto Hospital, University of Toronto, we observed that 6 patients complained of unpleasant paresthesiae with paresthesiae-producing DBS, preventing permanent electrode implantation in all of them. Such patients accounted for 15% of the failures (6 out of 40 failures) in our series. In an attempt to improve patient selection, we reviewed our patients considering a number of parameters in order to determine risk factors for unpleasant paresthesiae elicited by paresthesiae-producing DBS. The results showed that this response happenned only in patients with brain central pain complaining of evoked pain, secondary to a supratentorial lesion. Age, sex, duration of pain, quality of the steady pain, size of the causative lesion and site (VC,ML,IC) and type (micro or macroelectrode) of surgical exploration were not important factors. Unpleasant paresthesiae in response to dorsal column stimulation, restricted thalamic lesion on computed tomography and the occurrence of associated intermittent pain were considered major risk factors in this subset of patients and the presence of cold allodynia or hyperpathia in isolation and the absence of sensory loss were considered minor risk factors. It is our hope that the criteria here established will improve patient selection and so, the overall results of DBS.<br>A estimulação cerebral profunda (ECP) de sítios cuja estimulação elicita parestesia (núcleo talâmico ventrocaudal - VC, lemnisco medial - LM e cápsula interna - CI) é um dos poucos métodos atualmente disponíveis para o tratamento do elemento constante da dor por injúria neural (DIN). Revendo os primeiros 60 pacientes com DIN submetidos à ECP na Division of Neurosurgery, Toronto Hospital, University of Toronto, no período 1978/ 1991, observamos que 6 destes pacientes apresentaram parestesia dolorosa à estimulação de VC/LM/ CI, prevenindo a definitiva implantação do sistema em todos eles e totalizando 15% (6 dentre 40) das falhas em nossa série. Em uma tentativa de se melhorar a seleção de pacientes para a ECP e, com isto, seus resultados globais, revimos nossos casos, considerando uma série de parâmetros, de modo a determinar os fatores de risco para parestesia dolorosa. Os resultados mostraram que esta resposta à estimulação de VC/LM/CI é exclusiva de pacientes com dor central cerebral, secundária a lesão supratentorial, apresentando dor evocada como parte do quadro doloroso. Nem todos os pacientes com estas características, porém, apresentavam parestesia dolorosa. O estudo comparativo destes dois subgrupos (dor central cerebral + dor evocada + parestesia dolorosa e dor central cerebral + dor evocada + parestesia dolorosa) permitiu definir que: 1. Parestesia dolorosa à estimulação da coluna dorsal da medula espinhal, lesão restrita ao tálamo à tomografia computorizada e dor intermitente como parte do quadro doloroso são fatores de risco maiores para parestesia dolorosa à estimulação de VC / LM / Cl; 2. Alodínia ao frio ou hiperpatia isoladamente e ausência de deficit sensitivo ao exame neurológico são fatores de risco menores; e 3. Idade, sexo, duração da dor, qualidade da dor constante, dimensões da lesão causal e sítio (VC, LM ou Cl) ou tipo (macro ou microeletrodo) da exploração cirúrgica não parecem ser fatores de risco relevantes. O autor sugere também os prováveis mecanismos fisiopatológicos envolvidos na gênese da parestesia dolorosa à estimulação de VC / LM / Cl