Systematic variation of the sodium/sulfur promoter content on carbon-supported iron catalysts for the Fischer–Tropsch to olefins reaction

The Fischer–Tropsch to olefins（FTO） process is a method for the direct conversion of synthesis gas to lower C–Colefins. Carbon-supported iron carbide nanoparticles are attractive catalysts for this reaction.The catalytic activity can be improved and undesired formation of alkanes can be suppressed by the addition of sodium and sulfur as promoters but the influence of their content and ratio remains poorly understood and the promoted catalysts often suffer from rapid deactivation due to particle growth. A series of carbon black-supported iron catalysts with similar iron content and nominal sodium/sulfur loadings of 1–30/0.5–5 wt% with respect to iron are prepared and characterized under FTO conditions at 1and 10 bar syngas pressure to illuminate the influence of the promoter level on the catalytic properties.Iron particles and promoters undergo significant reorganization during FTO operation under industrially relevant conditions. Low sodium content（1–3 wt%） leads to a delay in iron carbide formation. Sodium contents of 15–30 wt% lead to rapid loss of catalytic activity due to the covering of the iron surface with promoters during particle growth under FTO operation. Higher activity and slower loss of activity are observed at low promoter contents（1–3 wt% sodium and 0.5–1 wt% sulfur） but a minimum amount of alkali is required to effectively suppress methane and C–Cparaffin formation. A reference catalyst support（carbide-derived carbon aerogel） shows that the optimum promoter level depends on iron particle size and support pore structure.

Backcalculation of the disease-age specific frequency of secondary transmission of primary pneumonic plague

The purpose of the paper was to assess the frequency of secondary transmissions of primary pneumonic plague relative to the onset of fever.A simple backcalculation method was employed to estimate the frequency of secondary transmissions relative to disease-age.A likelihood-based procedure was taken using observed distributions of the serial interval(n = 177) and incubation period(n = 126).Furthermore,an extended model was developed to account for the survival probability of cases.The simple backcalculation suggested that 31. 0%(95%confidence intervals(CI):11.6,50.4) and 28.0%(95%CI:10.2,45.8) of the total number of secondary transmissions had occurred at second and third days of the disease,respectively,and more than four-fifths of the secondary transmission occurred before the end of third day of disease.The survivorship-adjusted frequency of secondary transmissions was obtained,demonstrating that the infectiousness in later stages of illness was not insignificant and indicates that the obtained frequencies were likely biased on underlying factors including isolation measures.In conclusion,the simple exercise suggests a need to implement countermeasures during pre-clinical stage or immediately after onset.Further information is needed to elucidate the finer details of the disease-age specific infectiousness.

Role of spleen tyrosine kinase in liver diseases

Spleen tyrosine kinase (SYK),a non-receptor tyrosine kinase,is expressed in most hematopoietic cells and non-hematopoietic cells and play a crucial role in both immune and non-immune biological responses.SYK mediate diverse cellular responses via an immune-receptor tyrosine-based activation motifs (ITAMs)-dependent signalling pathways,ITAMs-independent and ITAMs-semidependent signalling pathways.In liver,SYK expression has been observed in parenchymal (hepatocytes) and non-parenchymal cells (hepatic stellate cells and Kupffer cells) and found to be positively correlated with the disease severity.The implication of SYK pathway has been reported in different liver diseases including liver fibrosis,viral hepatitis,alcoholic liver disease,non-alcoholic steatohepatitis and hepatocellular carcinoma.Antagonism of SYK pathway using kinase inhibitors have shown to attenuate the progression of liver diseases thereby suggesting SYK as a highly promising therapeutic target.This review summarizes the current understanding of SYK and its therapeutic implication in liver diseases.

Distinct metamorphic evolution of alternating silica-saturated and silica-deficient microdomains within garnet in ultrahigh-temperature granulites: An example from Sri Lanka

Here we report the occurrence of garnet porphyroblasts that have overgrown alternating silica-saturated and silica deficient microdomains via different mineral reactions. The samples were collected from ultrahigh-temperature(UHT) metapelites in the Highland Complex, Sri Lanka. In some of the metapelites, garnet crystals have cores formed via a dehydration reaction, which had taken place at silicasaturated microdomains and mantle to rim areas formed via a dehydration reaction at silica-deficient microdomains. In contrast, some other garnets in the same rock cores had formed via a dehydration reaction which occurred at silica-deficient microdomains while mantle to rim areas formed via a dehydration reaction at silica-saturated microdomains. Based on the textural observations, we conclude that the studied garnets have grown across different effective bulk compositional microdomains during the prograde evolution. These microdomains could represent heterogeneous compositional layers(paleobedding/laminations) in the precursor sediments or differentiated crenulation cleavages that existed during prograde metamorphism. UHT metamorphism associated with strong ductile deformation, metamorphic differentiation and crystallization of locally produced melt may have obliterated the evidence for such microdomains in the matrix. The lack of significant compositional zoning in garnet probably due to self-diffusion during UHT metamorphism had left mineral inclusions as the sole evidence for earlier microdomains with contrasting chemistry.

Potential therapeutic benefits stemming from the thermal nature of irreversible electropora tion of solid cancers

To the Editor：Irreversible electroporation （IRE） is a CE- and FDA- approved treatment modality for pancreatic and liver tumors that is based on the site-confined destruction of tumor tissue by multiple short, high-intensity electrical pulses.

Synthesis of a Green Nano-Silica Material Using Beneficiated Waste Dunites and Its Application in Concrete

Nano-silica, one of the substances boosting the field of nanomaterials, can be produced by dissolving olivine in acid. The dissolution of olivine is a convenient alternative route to the existing methods of nano-silica production (neutralization of sodium silicate and flame hydrolysis) because the olivine dissolution is a low temperature process making this method cheaper and greener. Furthermore, this process can use waste olivine materials for the production of nano-silica. The produced nano-silica has a specific surface area between 100 and 400 m2/g;a primary particle size between 10 and 25 nm, which is agglomerated in clusters;and an impurity content below 5 wt.%. In addition, olivine nano-silica can be classified as a pozzolanic material with an activity index of 101%. The optimum replacement level of olivine nano-silica in conventional vibrated concrete is around 5% by volume resulting in: 1) a compressive strength increase of 20%;2) a CO2 emission reduction of 3%. Therefore, the use of the olivine nano-silica in CVC does not only improve the compressive strength but also reduce the CO2 emissions.

The Global Stratotype Section and Point （GSSP） for the base of the Holocene Series/Epoch （Quaternary System/Period） in the NGRIP ice core

The Greenland ice core from NorthGRIP （NGRIP） contains a proxy climate record across the Pleistocene-Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision.

Epidemiologic analysis of a previous outbreak of bubonic plague:The first identified outbreak with bacteriological confirmation in Kobe and Osaka,Japan

Objective:To characterize the case fatality and estimate the symptomatic period of bubonic plague.Methods: Epidemiologic analyses of a previous outbreak of plague in Osaka and Kobe,two major port cities in Japan, from 1899-1900 were performed.In addition to date of onset of symptoms,gender,age and the date of death were extracted from the historical data.The time from onset to death(symptomatic period) was fitted to gamma distribution using the maximum likelihood method.Results:Temporal distribution revealed suspected chains of transmission of the primary pneumonic plague at the late stage of the outbreak.The case fatality of bubonic plague without specific treatment was 83.4%,and the mean time from onset to death was estimated as 4.7 days(95%confidence interval;4.0,5.5).Conclusion:Case fatality of bubonic plague without specific treatment was extremely high.The symptomatic period of bubonic plague appeared to be longer than that of pneumonic plague.

产业特征对产业国际化进程的影响--以跨国并购为例

产业国际化对中国三十多年的经济增长和结构变迁产生了举足轻重的作用。由于不同产业的国际化进程存在着很大的差别,这种差别一定程度上导致了产业发展的差异性和产业结构的变化。因此,要深入探讨我国的产业发展和结构的变迁就有必要研究产业特征对产业国际化进程的影响。随着中国国际化进程的不断深入,产业国际化的方式逐渐从单一的出口转向出口与对外直接投资并进。在这一过程中,海外并购逐渐成为对外直接投资的一个重要渠道。通过海外并购,企业可以迅速有效地获得并购目标的品牌、管理技能、研究能力、资源和销售渠道等战略资产,有利于产业竞争力的提升。本文运用2003—2009年中国企业海外并购的数据对36个产业的国际化与其产业特征的关系进行分析。结果表明,产业海外并购的动机和能力与产业收益、产业的技术密集度、产业出口强度和产业规模成显著的正相关关系,而与产业的劳动密集度成显著的负相关关系;同时,出口强度对要素密集度与海外并购的关系有显著的调节作用,而且对两种要素(技术和劳动)的调节作用方向相反。这一结果帮助我们认识中国企业海外并购的产业条件,为产业政策的制定提供参考。

运输应激猪肝脏中热应激蛋白的定位与表达

利用免疫组织化学定位方法和Westernblot技术 ,对长途运输试验猪肝脏中 5种不同分子量的热应激蛋白HSP70 、HSP72 、HSP86、HSP90 和HSP2 7进行定位和表达。所有长途运输后应激猪和对照猪肝脏组织中均同时检测到了上述 5种HSP。肝细胞胞浆和胞核均显示阳性信号 ,但HSPs在肝细胞中的定位有差异 ,大多数HSP70 、HSP72 和HSP2 7主要分布于肝细胞胞浆内 ,而HSP90 和HSP86阳性颗粒在核内的分布比其在胞浆中的分布更为明显。肝小叶周边区有明显颗粒变性和脂肪变性的肝细胞中HSPs的阳性染色信号较弱。 6h的长途运输应激后 ,与对照组相比 ,HSPs在肝脏组织中的表达量存在差异 ,表现为HSP70 家族的HSP70 和HSP72 的表达没有明显的升高 (P >0 .0 5 ) ,HSP90 家族的HSP90 的表达出现极显著的增加 (P <0 .0 1) ,然而 ,HSP90 家族的HSP86和小分子量家族的HSP2 7的表达量呈现明显的下降 (P <0 .0 5 )。

Deposits and depositional sequence nearby Iluanghe Harbour in the Huanghe River Delta

The sedimentary sequence of the upper 4 m deposits in the Huanghe Harbour Pit is as follows, 1, Distributary mouth bar deposits formed before 1964; 2. lower delta plain (tidal flat) and subaqueous delta lateral deposits formed in the period of 1964-1972; 3. deposits of crevasse splay and distributary channel near mouth, formed in the period of 1972-1974; 4. tidal flat deposits formed in the period of 1975-1984. The sequence shows superimposition of sedimentary environments parallel to coastline.

Short-term exposure to ambient ozone associated with cardiac arrhythmias in healthy adults

Objective The exact biological mechanism whereby exposure to ambient ozone(O3)may contribute to clinical onset of cardiovascular events remains unclear.In this study,we aim to examine the impacts of O3 exposure on cardiac arrhythmias and potential pathways involved through autonomic dysfunction and myocardial injury.Methods Seventy-three non-smoking healthy adults were followed with 4 repeated measurements of 24-hour ambulatory arrhythmias,heart rate variability,ST-segment deviation,and blood pressure(BP)in Beijing,China,2014‒2016.Generalized additive mixed models coupled with distributed lag nonlinear models were constructed to evaluate the associations and potential interlinks between O3 exposure and outcome measurements.Results During the study period,24-hour average concentrations of ambient O3 were 47.4µg/m3(ranging from 1.0 to 165.9µg/m3).Increased risks of premature ventricular contraction and ventricular tachycardia were associated with interquartile range increases in O3 exposure during the last 5 days before each participant's clinic visit,with relative risks of 2.14(95%confidence interval[CI]:1.95 to 2.32)and 5.47(95%CI:3.51 to 7.43),respectively.Mediation analyses further showed that sympathetic activation,parasympathetic inhibition,and elevated BP levels,as well as heightened risks of ST-segment depression could mediate up to 47.74%of the risks of arrhythmias attributable to O3 exposure.Conclusion Our results suggest that short-term exposure to ambient O3 could prompt the genesis of arrhythmias partially through worsening autonomic function and myocardial burden.

Dissipation-induced instabilities and symmetry

The paradox of destabilization of a conservative or non-conservative system by small dissipation,or Ziegler’s paradox（1952）,has stimulated a growing interest in the sensitivity of reversible and Hamiltonian systems with respect to dissipative perturbations.Since the last decade it has been widely accepted that dissipation-induced instabilities are closely related to singularities arising on the stability boundary,associated with Whitney’s umbrella.The first explanation of Ziegler’s paradox was given（much earlier）by Oene Bottema in 1956.The aspects of the mechanics and geometry of dissipation-induced instabilities with an application to rotor dynamics are discussed.

Interpreting Kuhn＇s Incommensurability-Thesis： Its Different Meanings and Epistemological Consequences

Kuhn＇s incommensurability-thesis is crucial for consequences for the pursuit of epistemology. A interpreting his views on the development of science and their commemoration of the 50th anniversary of the publication of the original version of Kuhn＇s epoch-making book The Structure of Scientific Revolutions （henceforth： SSR） should thus provide a thorough reflection on this thesis. However, this thesis is not easy to interpret. It is not only complex in itself but has also undergone a historical development--in Kuhn＇s own hands and in those of his interpreters. In this article, I sort out the different interpretations of it, in particular, in Part A. In Part B, I demonstrate their epistemological consequences. Under closer scrutiny, Kuhn＇s incommensurability-thesis contains several sub-theses Different senses of ＂incommensurability＂ thus need to be distinguished. However, the way in which those distinctions are drawn in Kuhn-scholarship differs. In paragraph I of Part A, I provide an overview of the reception of the incommensurability-thesis in Kuhn-scholarship. In Paragraph II, I trace its development in Kuhn＇s later writings： given its importance and contested nature, Kuhn later clarifies his original thesis. Those later clarifications＇ main function consists in domesticating the most radically relativistic aspects his original incommensurability-thesis had, at least, in the eyes of his interpreters. The upshot of Part A （Paragraphs I and II） is to provide a coherent interpretation of Kuhn＇s incommensurability-thesis. To that end, I distinguish in line with much of Kuhn-scholarship a semantic from a methodological sense of incommensurability. In part B, the question is raised： What sort of epistemological consequences follow from both senses of incommensurability？ In particular, what consequences follow for the issues of reference, subjectivity （objectivity）, pluralism, and realism？ The underlying question is to what extent Kuhnian incommensurability caters to a relativistic understanding of those issues. This question is answered in Paragraph Ill with the help of the analyses of a currently leading Kuhn-scholar, C. H. Sankey. His answers are taken as a vantage point for my concluding evaluation of the consequences of Kuhnian incommensurability in Paragraph IV.

标准孢粉载片中有机质类型的鉴别

本文提供了标准孢粉载片中分散有机质典型分类的基本轮廓.

Roles of Arabidopsis Patatin-Related Phospholipases A in Root Development Are Related to Auxin Responses and Phosphate Deficiency

Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholipase A （pPLA） genes AtPLAIVA, AtPLAIVB, and AtPLAIVC and their corresponding proteins. Loss-of-function mutants reveal roles for these pPLAs in roots during normal development and under phosphate deprivation. AtPLAIVA is expressed strongly and exclusively in roots and AtplalVA-null mutants have reduced lateral root development, characteristic of an impaired auxin response. By contrast, AtPLAIVB is expressed weakly in roots, cotyledons, and leaves but is transcriptionally induced by auxin, although AtplalVB mutants develop normally. AtPLAIVC is expressed in the floral gynaecium and is induced by abscisic acid （ABA） or phosphate deficiency in roots. While an AtplalVC-1 loss-of-function mutant displays ABA respon- siveness, it exhibits an impaired response to phosphate deficiency during root development. Recombinant AtPLA proteins hydrolyze preferentially galactolipids and, less efficiently, phospholipids, although these enzymes are not localized in chloroplasts. We find that AtPLAIVA and AtPLAIVB are phosphorylated by calcium-dependent protein kinases in vitro and this enhances their activities on phosphatidylcholine but not on phosphatidylglycerol. Taken together, the data reveal novel functions of pPLAs in root development with individual roles at the interface between phosphate deficiency and auxin signaling.

Management of extracranial carotid artery stenosis during endovascular treatment for acute ischaemic stroke:results from the MR CLEAN Registry

Background The optimal management of ipsilateral extracranial internal carotid artery(ICA)stenosis during endovascular treatment(EVT)is unclear.We compared the outcomes of two different strategies:EVT with vs without carotid artery stenting(CAS).Methods In this observational study,we included patients who had an acute ischaemic stroke undergoing EVT and a concomitant ipsilateral extracranial ICA stenosis of≥50%or occlusion of presumed atherosclerotic origin,from the Dutch Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands(MR CLEAN)Registry(2014-2017).The primary endpoint was a good functional outcome at 90 days,defined as a modified Rankin Scale score≤2.Secondary endpoints were successful intracranial reperfusion,new clot in a different vascular territory,symptomatic intracranial haemorrhage,recurrent ischaemic stroke and any serious adverse event.Results Of the 433 included patients,169(39%)underwent EVT with CAS.In 123/168(73%)patients,CAS was performed before intracranial thrombectomy.In 42/224(19%)patients who underwent EVT without CAS,a deferred carotid endarterectomy or CAS was performed.EVT with and without CAS were associated with similar proportions of good functional outcome(47%vs 42%,respectively;adjusted OR(aOR),0.90;95%CI,0.50 to 1.62).There were no major differences between the groups in any of the secondary endpoints,except for the increased odds of a new clot in a different vascular territory in the EVT with CAS group(aOR,2.96;95%CI,1.07 to 8.21).Conclusions Functional outcomes were comparable after EVT with and without CAS.CAS during EVT might be a feasible option to treat the extracranial ICA stenosis but randomised studies are warranted to prove non-inferiority or superiority.

Moving interdisciplinary science forward:integrating participatory modelling with mathematical modelling of zoonotic disease in Africa

This review outlines the benefits of using multiple approaches to improve model design and facilitate multidisciplinary research into infectious diseases,as well as showing and proposing practical examples of effective integration.It looks particularly at the benefits of using participatory research in conjunction with traditional modelling methods to potentially improve disease research,control and management.Integrated approaches can lead to more realistic mathematical models which in turn can assist with making policy decisions that reduce disease and benefit local people.The emergence,risk,spread and control of diseases are affected by many complex bio-physical,environmental and socio-economic factors.These include climate and environmental change,land-use variation,changes in population and people’s behaviour.The evidence base for this scoping review comes from the work of a consortium,with the aim of integrating modelling approaches traditionally used in epidemiological,ecological and development research.A total of five examples of the impacts of participatory research on the choice of model structure are presented.Example 1 focused on using participatory research as a tool to structure a model.Example 2 looks at identifying the most relevant parameters of the system.Example 3 concentrates on identifying the most relevant regime of the system(e.g.,temporal stability or otherwise),Example 4 examines the feedbacks from mathematical models to guide participatory research and Example 5 goes beyond the so-far described two-way interplay between participatory and mathematical approaches to look at the integration of multiple methods and frameworks.This scoping review describes examples of best practice in the use of participatory methods,illustrating their potential to overcome disciplinary hurdles and promote multidisciplinary collaboration,with the aim of making models and their predictions more useful for decision-making and policy formulation.

Identification of common and distinct origins of human serum and breastmilk IgA1 by mass spectrometry-based clonal profiling

The most abundant immunoglobulin present in the human body is IgA. It has the highest concentrations at the mucosal lining and in biofluids such as milk and is the second most abundant class of antibodies in serum. We assessed the structural diversity and clonal repertoire of IgA1-containing molecular assemblies longitudinally in human serum and milk from three donors using a mass spectrometry-based approach. IgA-containing molecules purified from serum or milk were assessed by the release and subsequent analysis of their Fab fragments. Our data revealed that serum IgA1 consists of two distinct structural populations, namely monomeric IgA1 (∼80%) and dimeric joining (J-) chain coupled IgA1 (∼20%). Also, we confirmed that IgA1 in milk is present solely as secretory (S)IgA, consisting of two (∼50%), three (∼33%) or four (∼17%) IgA1 molecules assembled with a J-chain and secretory component (SC). Interestingly, the serum and milk IgA1-Fab repertoires were distinct between monomeric, and J-chain coupled dimeric IgA1. The serum dimeric J-chain coupled IgA1 repertoire contained several abundant clones also observed in the milk IgA1 repertoire. The latter repertoire had little to no overlap with the serum monomeric IgA1 repertoire. This suggests that human IgA1s have (at least) two distinct origins;one of these produces dimeric J-chain coupled IgA1 molecules, shared in human serum and milk, and another produces monomeric IgA1 ending up exclusively in serum.

动脉瘤性蛛网膜下腔出血患者的重症监护处理：神经危重症监护学会多学科共识会议的推荐意见

蛛网膜下腔出血（subarachnoidhemorrhage，SAH）是一种可对中枢神经系统造成毁灭性打击并对其他多个器官产生显著影响的急性脑血管病。SAH患者被常规收入重症监护病房并由多学科团队进行治疗。由于高质量研究证据的缺乏，使得治疗方法各异，可供选择的指导意见不多。现有的指南主要强调危险因素、预防、自然史以及再出血的预防，很少涉及SAH患者的重症监护问题。美国神经危重症监护学会组织了一次国际性多学科共识会议来探讨SAH的重症监护处理。根据发表的文章和研究领域，此次会议召集了来自欧洲和北美地区的神经重症监护科、神经外科、神经内科、介入神经放射科和神经麻醉科方面的专家。根据临床经验和制定实践指南方面的经验，选择4名经验丰富的神经重症监护专家组成评判委员会。应用推荐分级的评估、制定与评价（GradesofRecommendationsAssessment，DevelopmentandEvaluation，GRADE）系统进行文献回顾，结合参会者的经验、评判委员会的审评以及文献讨论产生推荐意见。应用GRADE系统制定推荐意见，其制定原则不仅强调研究资料的质量，而且还重视利弊权衡与实践转化。对SAH患者日常处理过程中面临的所有问题均提供指导和推荐意见，即使缺乏高质量的证据。