ABSTRACT
We present an extended monthly and seasonal Greenland Blocking Index (GBI) from January 1851 to December 2015, which more than doubles the length of the existing published GBI series. We ...achieve this by homogenizing the Twentieth Century Reanalysis version 2c‐based GBI and splicing it with the NCEP/NCAR Reanalysis‐based GBI. For the whole time period, there are significant decreases in GBI in autumn, October and November, and no significant monthly, seasonal or annual increases. More recently, since 1981 there are significant GBI increases in all seasons and annually, with the strongest monthly increases in July and August. A recent clustering of high GBI values is evident in summer, when 7 of the top 11 values in the last 165 years – including the two latest years 2014 and 2015 – occurred since 2007. Also, 2010 is the highest GBI year in the annual, spring, winter and December series but 2011 is the record low GBI value in the spring and April series. Moreover, since 1851 there have been significant increases in GBI variability in May and especially December. December has also shown a significant clustering of extreme high and low GBI values since 2001, mirroring a similar, recently identified phenomenon in the December North Atlantic Oscillation index, suggesting a related driving mechanism. We discuss changes in hemispheric circulation that are associated with high compared with low GBI conditions. Our GBI time series should be useful for climatologists and other scientists interested in aspects and impacts of Arctic variability and change.
Graphene/Mn3O4 composites were prepared by a simple hydrothermal process from KMnO4 using ethylene glycol as a reducing agent. Mn3O4 nanorods of 100 nm to 1 μm length were observed to be ...well-dispersed on graphene sheets. To assess the properties of these materials for use in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements were performed. Graphene/Mn3O4 composites could be charged and discharged faster and had higher capacitance than free Mn3O4 nanorods. The capacitance of the composites was 100% retained after 10 000 cycles at a charging rate of 5 A/g.
Reliable and quantifiable high-resolution protein localization is critical for understanding protein function. However, the time required to clone and characterize any protein of interest is a ...significant bottleneck, especially for electron microscopy (EM). We present a modular system for enzyme-based protein tagging that allows for improved speed and sampling for analysis of subcellular protein distributions using existing clone libraries to EM-resolution. We demonstrate that we can target a modified soybean ascorbate peroxidase (APEX) to any GFP-tagged protein of interest by engineering a GFP-binding peptide (GBP) directly to the APEX-tag. We demonstrate that APEX-GBP (1) significantly reduces the time required to characterize subcellular protein distributions of whole libraries to less than 3 days, (2) provides remarkable high-resolution localization of proteins to organelle subdomains, and (3) allows EM localization of GFP-tagged proteins, including proteins expressed at endogenous levels, in vivo by crossing existing GFP-tagged transgenic zebrafish lines with APEX-GBP transgenic lines.
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•APEX-GBP allows for high-resolution subcellular protein distribution analyses•APEX-GBP allows for quantitative and volumetric assessment of protein distribution•APEX-GBP is conducive to rapid screening of GFP-tagged clone libraries by EM•APEX-GBP is a sensitive and inducible system for protein localization in vivo
Rapid screening with electron microscopy (EM)-based analysis has been difficult. Here, Ariotti et al. generate and characterize a system for fast, sensitive, and reliable localization of GFP-tagged proteins to nanometer resolution. APEX-GBP zebrafish lines are also crossed with GFP-tagged lines to rapidly determine whole organism protein distribution at EM resolution.
We present a homogenized Greenland blocking index (GBI) daily record from 1851 to 2015, therefore significantly extending our previously published monthly/seasonal GBI analysis. This new time series ...is analysed for evidence of changes in extreme events, and we investigate the underlying thermodynamic and dynamic precursors. We compare occurrences and changes in extreme events between our GBI record and a recently published, temporally similar daily North Atlantic Oscillation (NAO) series, and use this comparison to test dynamic meteorology hypotheses relating negative NAO to Greenland blocking. We also compare daily GBI changes and extreme events with long‐running indices of England and Wales temperature and precipitation, to assess potential downstream effects of Greenland blocking on UK extreme weather events and climate change. In this extended analysis we show that there have been sustained periods of positive GBI during 1870–1900 and from the late 1990s to present. A clustering of extreme high GBI events since 2000 is not consistently reflected by a similar grouping of extreme low NAO events. Case studies of North Atlantic atmospheric circulation changes linked with extreme high and low daily GBI episodes are used to shed light on potential linkages between Greenland blocking and jet‐stream changes. Particularly noteworthy is a clustering of extreme high GBI events during mid‐October in 4 out of 5 years during 2002–2006, which we investigate from both cryospheric and dynamic meteorology perspectives. Supporting evidence suggests that these autumn extreme GBI episodes may have been influenced by regional sea‐ice anomalies off west Greenland but were probably largely forced by increases in Rossby‐wave train activity originating from the tropical Pacific. However, more generally our results indicate that high GBI winter anomalies are co‐located with sea‐ice anomalies, while there seems to be minimal influence of sea‐ice anomalies on the recent significant increase in summer GBI.
Since 2000 there has been a sustained period of high Greenland blocking, especially in summer. Case studies of atmospheric circulation changes linked with extreme daily Greenland blocking episodes are used to shed light on linkages with North Atlantic jet‐stream changes and possible connections with extreme weather events over the UK. Particularly noteworthy is a clustering of extreme high blocking events during mid‐October in 4 out of 5 years during 2002–2006, which we investigate from both cryospheric and dynamic meteorology perspectives.
Summary Background The attacks on the World Trade Center (WTC) on Sept 11, 2001 (9/11) created the potential for occupational exposure to known and suspected carcinogens. We examined cancer incidence ...and its potential association with exposure in the first 7 years after 9/11 in firefighters with health information before 9/11 and minimal loss to follow-up. Methods We assessed 9853 men who were employed as firefighters on Jan 1, 1996. On and after 9/11, person-time for 8927 firefighters was classified as WTC-exposed; all person-time before 9/11, and person-time after 9/11 for 926 non-WTC-exposed firefighters, was classified as non-WTC exposed. Cancer cases were confirmed by matches with state tumour registries or through appropriate documentation. We estimated the ratio of incidence rates in WTC-exposed firefighters to non-exposed firefighters, adjusted for age, race and ethnic origin, and secular trends, with the US National Cancer Institute Surveillance Epidemiology and End Results (SEER) reference population. CIs were estimated with overdispersed Poisson models. Additional analyses included corrections for potential surveillance bias and modified cohort inclusion criteria. Findings Compared with the general male population in the USA with a similar demographic mix, the standardised incidence ratios (SIRs) of the cancer incidence in WTC-exposed firefighters was 1·10 (95% CI 0·98–1·25). When compared with non-exposed firefighters, the SIR of cancer incidence in WTC-exposed firefighters was 1·19 (95% CI 0·96–1·47) corrected for possible surveillance bias and 1·32 (1·07–1·62) without correction for surveillance bias. Secondary analyses showed similar effect sizes. Interpretation We reported a modest excess of cancer cases in the WTC-exposed cohort. We remain cautious in our interpretation of this finding because the time since 9/11 is short for cancer outcomes, and the reported excess of cancers is not limited to specific organ types. As in any observational study, we cannot rule out the possibility that effects in the exposed group might be due to unidentified confounders. Continued follow-up will be important and should include cancer screening and prevention strategies. Funding National Institute for Occupational Safety and Health.
We compare the performance of five magnesium (Mg2+) ion models in simulations of an RNA stem loop which has an experimentally determined divalent ion dependent conformational shift. We show that ...despite their differences in parametrization and resulting van der Waals terms, including differences in the functional form of the nonbonded potential, when the RNA adopts its folded conformation, all models behave similarly across ten independent microsecond length simulations with each ion model. However, when the entire structure ensemble is accounted for, chelation of Mg2+ to RNA is seen in three of the five models, most egregiously and likely artifactual in simulations using a 12-6-4 model for the Lennard-Jones potential. Despite the simple nature of the fixed point-charge and van der Waals sphere models employed, and with the exception of the likely oversampled directed chelation of the 12-6-4 potential models, RNA–Mg2+ interactions via first shell water molecules are surprisingly well described by modern parameters, allowing us to observe the spontaneous conformational shift from Mg2+ free RNA to Mg2+ associated RNA structure in unrestrained molecular dynamics simulations.
Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the ...innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.
Adult zebrafish show a remarkable capacity to regenerate their spinal column after injury, an ability that stands in stark contrast to the limited repair that occurs within the mammalian CNS ...post-injury. The reasons for this interspecies difference in regenerative capacity remain unclear. Here we demonstrate a novel role for Fgf signaling during glial cell morphogenesis in promoting axonal regeneration after spinal cord injury. Zebrafish glia are induced by Fgf signaling, to form an elongated bipolar morphology that forms a bridge between the two sides of the resected spinal cord, over which regenerating axons actively migrate. Loss of Fgf function inhibits formation of this "glial bridge" and prevents axon regeneration. Despite the poor potential for mammalian axonal regeneration, primate astrocytes activated by Fgf signaling adopt a similar morphology to that induced in zebrafish glia. This suggests that differential Fgf regulation, rather than intrinsic cell differences, underlie the distinct responses of mammalian and zebrafish glia to injury.
Metal–organic frameworks (MOFs) provide access to structures with nanoscale pores, the size and connectivity of which can be controlled by combining the appropriate metals and linkers. To date, there ...have been no reports of using MOFs as templates to make porous, crystalline metal oxides. Microporous titania replicas were made from the MOF template HKUST-1 by dehydration, infiltration with titanium isopropoxide, and subsequent hydrothermal treatment at 200 °C. Etching of the MOF with 1 M aqueous HCl followed by 5% H2O2 yielded a titania replica that retained the morphology of the parent HKUST-1 crystals and contained partially ordered micropores as well as disordered mesopores. Interestingly, the synthesis of porous titania from the HKUST-1 template stabilized the formation of brookite, a rare titania polymorph.
Summary Background Perioperative respiratory adverse events (PRAE) are the most common critical incidents in paediatric anaesthesia and occur more often in infants. Use of laryngeal mask airways ...(LMAs) is associated with reduced PRAE compared with endotracheal tubes in older children (>1 year). We aimed to evaluate the effect of these devices on the incidence of PRAE in infants. Methods We did a randomised controlled trial at the Princess Margaret Hospital for Children in Perth (WA, Australia) by recruiting infants (aged 0–12 months) undergoing general (with or without regional or local) anaesthesia with anticipated fentanyl dose 1 μg/kg or lower for minor elective surgery. We excluded patients contraindicated for LMA or endotracheal tube; who had known cardiac disease or airway or thoracic malformations; who were receiving midazolam premedication; who were undergoing airway, thoracic, or abdomen surgery at the time of participation; and if the parents did not speak English. Written parental or guardian consent was obtained before enrolment. Participants were randomly assigned (1:1), by computer-generated variable block randomisation, to receive an LMA (PRO-Breathe, Well Lead Medical Co Ltd, Panyu, China) or an endotracheal tube (Microcuff, Halyard Health Inc, Atlanta, GA, USA). Sealed randomisation envelopes were used to conceal device assignment. An interim analysis was planned once half the number of infants needed (145) had been recruited. The primary outcome was incidence of PRAE, assessed in the intention-to-treat population. The institutional ethics committee at the Princess Margaret Hospital for Children granted ethical approval (1786/EP). The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000250033). Findings The trial began on July 8, 2010, and was ended early on May 7, 2015, after the interim analysis results met the study stopping rules. During this time, 239 infants were assessed and 181 eligible infants were randomly assigned to receive an LMA (n=85) or an endotracheal tube (n=95). Four infants were not included in the analysis (two due to cancelled procedures, one did not meet inclusion criteria, and one with missing dataset). In the intention-to-treat analysis, PRAE occurred in 50 (53%) infants in the endotracheal tube group and in 15 (18%) infants in the LMA group (risk ratio RR 2·94, 95% CI 1·79–4·83, p<0·0001). Laryngospasm and bronchospasm (major PRAE) were recorded in 18 (19%) infants in the endotracheal tube group and in three (4%) infants in the LMA group (RR 5·30, 95% CI 1·62–17·35, p=0·002). No deaths were reported. Interpretation In infants undergoing minor elective procedures, LMAs were associated with clinically significantly fewer PRAE and lower occurrence of major PRAE (laryngospasm and bronchospasm) than endotracheal tubes. This difference should be a consideration in airway device selection. Funding Princess Margaret Hospital Foundation, National Health and Australian Medical Research Council, Stan Perron Charitable Trust, and Callahan Estate.
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