Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportati...Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new展开更多
Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF),...Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.展开更多
引言血管性认知损害（vascular cognitive impairment,VCI）诊断共识的缺乏（体现为多种不同评估方案的使用）,妨碍了对其理解和治疗的推进.多个国家的大量临床医生和研究人员参与了2个阶段血管性认知损害分类共识研究（Vascular Impair...引言血管性认知损害（vascular cognitive impairment,VCI）诊断共识的缺乏（体现为多种不同评估方案的使用）,妨碍了对其理解和治疗的推进.多个国家的大量临床医生和研究人员参与了2个阶段血管性认知损害分类共识研究（Vascular Impairment of Cognition Classification Consensus Study,VICCCS）,旨在就VCI的诊断原则（VICCCS-1）和诊断方案（VICCCS-2）达成一致意见.本文提供了VICCCS-2的相关内容.方法使用VICCCS-1达成的原则和已发表的诊断指南作为在线德尔菲（Delphi）调查的参考基点,以期对VCI的临床诊断达成共识.结果共进行了6轮调查,每轮有65～79名专家参与,他们就VICCCS修订的轻度和重度VCI的诊断指南达成共识,并肯定了美国国立神经疾病与卒中研究所-加拿大卒中网（National Institute of Neurological Disorders and Stroke–Canadian Stroke Network,NINDS-CSN）发布的神经心理学评估方案和对影像学检查的推荐意见.讨论VICCCS-2建议规范化应用NINDS-CSN推荐的神经心理学和影像学评估方案诊断VCI,以促进研究协作.展开更多
Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a com...Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species （ROS）. Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane-localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.展开更多
The aim of this paper is to review the development and state of the art in the application of certain organosilicon compounds known as trialkoxysilanes （or simply silanes） to the problems of the metal finishing indu...The aim of this paper is to review the development and state of the art in the application of certain organosilicon compounds known as trialkoxysilanes （or simply silanes） to the problems of the metal finishing industry. The ultimate goal of this work is the replacement of chromate passivation and paint pretreatments, as well as overcoming the shortcomings of organic coatings formulated in the modern environmentally friendly world, thus without chromate or chromated pigments, volatile organic carbon （VOC） containing compounds or harazardous air pollutants （HAPs）.展开更多
Macronutrients （N, P, K, Ca, Mg, and S） in litter of three primarily spruce （Picea purpurea Masters） （SF）, fir （Abies faxoniana Rehder ＆ E. H. Wilson） （FF）, and birch （Betula platyphylla Sukaczev） （BF） ...Macronutrients （N, P, K, Ca, Mg, and S） in litter of three primarily spruce （Picea purpurea Masters） （SF）, fir （Abies faxoniana Rehder ＆ E. H. Wilson） （FF）, and birch （Betula platyphylla Sukaczev） （BF） subalpine forests in western China were measured to understand the monthly variations in litter nutrient concentrations and annual and monthly nutrient returns via litteffall. Nutrient concentration in litter showed the rank order of Ca 〉 N 〉 Mg 〉 K 〉 S 〉 P. Monthly variations in nutrient concentrations were greater in leaf litter （LL） than other litter components. The highest and lowest concentrations of N, P, K, and S in LL were found in the growing season and the nongrowing season, respectively, but Ca and Mg were the opposite. Nutrient returns via litterfall showed a marked monthly pattern with a major peak in October and one or two small peaks in February and/or May, varying with the element and stand type, but no marked monthly variations in nutrient returns via woody litter, reproductive litter, except in May for the BF, and moss litter. Not only litter production but also nutrient concentration controlled the annual nutrient return and the monthly nutrient return pattern. The monthly patterns of the nutrient concentration and return were of ecological importance for nutrient cycling and plant growth in the subalpine forest ecosystems.展开更多
AIM:To study the clinical efficacy and safety of Fecal microbiota transplantation(FMT).We systematically reviewed FMT used as clinical therapy.METHODS:We searched MEDLINE,EMBASE,the Cochrane Library and Conference pro...AIM:To study the clinical efficacy and safety of Fecal microbiota transplantation(FMT).We systematically reviewed FMT used as clinical therapy.METHODS:We searched MEDLINE,EMBASE,the Cochrane Library and Conference proceedings from inception to July,2013.Treatment effect of FMT was calculated as the percentage of patients who achieved clinical improvement per patient category,on an intention-to-treat basis.RESULTS:We included 45 studies;34 on Clostridium difficile-infection(CDI),7 on inflammatory bowel disease,1 on metabolic syndrome,1 on constipation,1 on pouchitis and 1 on irritable bowel syndrome(IBS).In CDI 90% resolution of diarrhea in 33 case series(n = 867) was reported,and 94% resolution of diarrhea after repeated FMT in a randomized controlled trial(RCT)(n = 16).In ulcerative colitis(UC) remission rates of 0% to 68% were found(n = 106).In Crohn's disease(CD)(n = 6),no benefit was observed.In IBS,70% improvement of symptoms was found(n = 13).100% Reversal of symptoms was observed in constipation(n = 3).In pouchitis,none of the patients(n = 8) achieved remission.One RCT showed significant improvement of insulin sensitivity in metabolic syndrome(n = 10).Serious adverse events were rare.CONCLUSION:FMT is highly effective in CDI,and holds promise in UC.As for CD,chronic constipation,pouchitis and IBS data are too limited to draw conclusions.FMT increases insulin sensitivity in metabolic syndrome.展开更多
Although suppressed serum testosterone （T） is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual （e.g., erectile dysfunction）, physical （e.g...Although suppressed serum testosterone （T） is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual （e.g., erectile dysfunction）, physical （e.g. loss of vigor and frailty） and psychological （e.g., depression） symptoms. This syndrome carries many names, including male menopause or climacterium, andropause and partial androgen deficiency of the ageing male （PADAM）. Late-onset hypogonadism （LOH） describes it best and is therefore generally preferred. The decrease of T in LOH is often marginal, and hypogonadism can be either due to primary testicular failure （low T, high luteinizing hormone （LH）） or secondary to a hypothalamic-pituitary failure （low T, low or inappropriately normal LH）. The latter form is more common and it is usually associated with overweight/obesity or chronic diseases （e.g., type 2 diabetes mellitus, the metabolic syndrome, cardiovascular and chronic obstructive pulmonary disease, and frailty）. A problem with the diagnosis of LOH is that often the symptoms （in 20%-40% of unselected men） and low circulating T （in 20% of men 〉70 years of age） do not coincide in the same individual. The European Male Ageing Study （EMAS） has recently defined the strict diagnostic criteria for LOH to include the simultaneous presence of reproducibly low serum T （total T 〈11 nmol 1-1 and free T 〈220 pmol 1-1） and three sexual symptoms （erectile dysfunction, and reduced frequency of sexual thoughts and morning erections）. By these criteria, only 2% of 40- to 80-year-old men have LOH. In particular obesity, but also impaired general health, are more common causes of low T than chronological age per se. Evidence-based information whether, and how, LOH should be treated is sparse. The most logical approach is lifestyle modification, weight reduction and good treatment of comorbid diseases. T replacement is widely used for the treatment, but evidence-based information about its real benefits展开更多
Hepatocellular carcinoma(HCC),the most common primary liver cancer,is one of the dreaded complications of chronic liver disease.Recent experimental and clinical studies have revealed that the alteration of gut-liver a...Hepatocellular carcinoma(HCC),the most common primary liver cancer,is one of the dreaded complications of chronic liver disease.Recent experimental and clinical studies have revealed that the alteration of gut-liver axis plays a pivotal role in the onset of chronic liver diseases,including HCC.Altered gut microbiota and endotoxemia are increasingly recognized as critical components in promoting the progression of chronic liver diseases to HCC.Probiotics have been suggested as a novel,safe and cost-effective approach to prevent or treat HCC.Mechanisms by which probiotics exerts their anti-cancer effects include their ability to bind carcinogens,modulation of gut microbiota,improvement of intestinal barrier function,and immunomodulation.This review summarizes the literature findings of the changes in gut microbiota linked to HCC,and discusses the possible therapeutic implications of probiotics for HCC.展开更多
Systemic inflammation is a marker of poor prognosis preoperatively present in around 20%-40%of colorectal cancer patients.The hallmarks of systemic inflammation include an increased production of proinflammatory cytok...Systemic inflammation is a marker of poor prognosis preoperatively present in around 20%-40%of colorectal cancer patients.The hallmarks of systemic inflammation include an increased production of proinflammatory cytokines and acute phase proteins that enter the circulation.While the low-level systemic inflammation is often clinically silent,its consequences are many and may ultimately lead to chronic cancer-associated wasting,cachexia.In this review,we discuss the pathogenesis of cancer-related systemic inflammation,explore the role of systemic inflammation in promoting cancer growth,escaping antitumor defense,and shifting metabolic pathways,and how these changes are related to less favorable outcome.展开更多
AIM:To study whether selected bacterial 16S ribosomal RNA(rRNA)gene phylotypes are capable of disting- uishing irritable bowel syndrome(IBS). METHODS:The faecal microbiota of twenty volunteers with IBS,subdivided into...AIM:To study whether selected bacterial 16S ribosomal RNA(rRNA)gene phylotypes are capable of disting- uishing irritable bowel syndrome(IBS). METHODS:The faecal microbiota of twenty volunteers with IBS,subdivided into eight diarrhoea-predominant (IBS-D),eight constipation-predominant(IBS-C)and four mixed symptom-subtype(IBS-M)IBS patients,and fifteen control subjects,were analysed at three time-points with a set of fourteen quantitative real-timepolymerase chain reaction assays.All assays targeted 16S rRNA gene phylotypes putatively associated with IBS,based on 16S rRNA gene library sequence analysis. The target phylotypes were affiliated with Actinobac-teria,Bacteroidetes and Firmicutes.Eight of the target phylotypes had less than 95%similarity to cultured bacterial species according to their 16S rRNA gene sequence.The data analyses were made with repeated-measures ANCOVA-type modelling of the data and principle component analysis(PCA)with linear mixed-effects models applied to the principal component scores. RESULTS:Bacterial phylotypes Clostridium cocleatum 88%,Clostridium thermosuccinogenes 85%,Coprobacillus catenaformis 91%,Ruminococcus bromii-like, Ruminococcus torques 91%,and R.torques 93%were detected from all samples analysed.A multivariate analysis of the relative quantities of all 14 bacterial 16S rRNA gene phylotypes suggested that the intestinal microbiota of the IBS-D patients differed from other sample groups.The PCA on the first principal component(PC1),explaining 30.36%of the observed variation in the IBS-D patient group,was significantly altered from all other sample groups(IBS-D vs control, P=0.01;IBS-D vs IBS-M,P=0.00;IBS-D vs IBS-C, P=0.05).Significant differences were also observed in the levels of distinct phylotypes using relative values in proportion to the total amount of bacteria.A phy- lotype with 85%similarity to C.thermosuccinogenes was quantified in significantly different quantities among the IBS-D and control subjects(-4.08±0.90 vs -3.33±1.16,P=0.04)and IBS-D and IBS-M subjects 展开更多
AIM： To characterize the bifidobacterial microbiota of the colonic mucosa in patients with colon cancer, inflammatory bowel disease or diverticulitis. METHODS： A sample of the distal colonic mucosa was taken during ...AIM： To characterize the bifidobacterial microbiota of the colonic mucosa in patients with colon cancer, inflammatory bowel disease or diverticulitis. METHODS： A sample of the distal colonic mucosa was taken during surgery from a total of 34 patients, twenty-one with diagnosed colorectal cancer, nine with diverticulitis and four with inflammatory bowel disease, requiring surgery for their condition. Bacterial DNA was extracted from the resected mucosal samples and bifidobacterial mucosa-associated microbiota was qualitatively and quantitatively determined by means of qualitative and quantitative PCR. RESULTS： Bifidobacteria were found in 100% of the samples from patients with diverticulitis or IBD and a 76% of those suffering colon cancer. The species B. Iongum and B. bifidum were the most widely found, followed by B. animalis, B. catenulatum and B. adolescentis. B. breve, B. dentium and B. angulatum were not detected in any sample. A significantly higher occurrence of B. Iongum was observed in patients with diverticulitis than in those with colon cancer or IBD （100%, 62% and 75%, respectively, P 〈 0.05）. Similar results were obtained for B, animalis （56%, 0% and 25%, P 〈 0.05）, while B. adolescentis was only found in the mucosa from patients with colon cancer （5 out of 21, 24%）. At the quantitative level, patients with colon cancer or IBD showed lower counts of total Bifidobacterium （4.94 and 5.91 vs 6.96 log Cells/sample, respectively, P 〈 0.05） and of the species B. longum （4.05 and 4.79 vs 6.76, P 〈 0.05） than those with diverticulitis.CONCLUSION： Aberrancies in mucosa associated microbiota are present in different intestinal diseases. This may indicate a role of the microbiota in the pathogenesis of these diseases.展开更多
Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the...Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species,the insulating nature of sulfur,and the fast capacity decay of the electrodes.Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites,as well as modifying the separators to physically/chemically retard the polysulfides migration.Two dimensional transition metal carbides,carbonitrides and nitrides,so-called MXenes,are ideal for confining the polysulfides shuttling effects due to their high conductivity,layered structure as well as rich surface terminations.As such,MXenes have thus been widely studied in Li-S batteries,focusing on the conductive sulfur hosts,polysulfides interfaces,and separators.Therefore,in this review,we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail.In addition,challenges and perspectives of MXenes for Li-S batteries are also outlined.展开更多
Probiotic bacteria have well-established beneficial ef-fects in the management of diarrhoeal diseases.Newer evidence suggests that probiotics have the potential to reduce the risk of developing inflammatory bowel dise...Probiotic bacteria have well-established beneficial ef-fects in the management of diarrhoeal diseases.Newer evidence suggests that probiotics have the potential to reduce the risk of developing inflammatory bowel diseases and intestinal bacterial overgrowth after gut surgery.In liver health,the main benefits of probiotics might occur through preventing the production and/or uptake of lipopolysaccharides in the gut,and therefore reducing levels of low-grade inflammation.Specific immune stimulation by probiotics through processes involving dendritic cells might also be beneficial to the host immunological status and help prevent pathogen translocation.Hepatic fat metabolism also seems to be influenced by the presence of commensal bacteria,and potentially by probiotics;although the mechanisms by which probiotic might act on the liver are still unclear.However,this might be of major importance in the fu-ture because low-grade inflammation,hepatic fat infil-tration,and hepatitis might become more prevalent as a result of high fat intake and the increased prevalence of obesity.展开更多
文摘Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new
基金the National Natural Science Foundation of China (Nos. 30471378, 90202010 and 30211130504),and the Program of 100 Distinguished Young Scientists of the Chinese Academy of Sciences.
文摘Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.
文摘引言血管性认知损害（vascular cognitive impairment,VCI）诊断共识的缺乏（体现为多种不同评估方案的使用）,妨碍了对其理解和治疗的推进.多个国家的大量临床医生和研究人员参与了2个阶段血管性认知损害分类共识研究（Vascular Impairment of Cognition Classification Consensus Study,VICCCS）,旨在就VCI的诊断原则（VICCCS-1）和诊断方案（VICCCS-2）达成一致意见.本文提供了VICCCS-2的相关内容.方法使用VICCCS-1达成的原则和已发表的诊断指南作为在线德尔菲（Delphi）调查的参考基点,以期对VCI的临床诊断达成共识.结果共进行了6轮调查,每轮有65～79名专家参与,他们就VICCCS修订的轻度和重度VCI的诊断指南达成共识,并肯定了美国国立神经疾病与卒中研究所-加拿大卒中网（National Institute of Neurological Disorders and Stroke–Canadian Stroke Network,NINDS-CSN）发布的神经心理学评估方案和对影像学检查的推荐意见.讨论VICCCS-2建议规范化应用NINDS-CSN推荐的神经心理学和影像学评估方案诊断VCI,以促进研究协作.
基金supported by the National Key Scientific Research Project(2011CB915400)supported by the National Natural Science Foundation of China(31730007)
文摘Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species （ROS）. Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane-localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.
文摘The aim of this paper is to review the development and state of the art in the application of certain organosilicon compounds known as trialkoxysilanes （or simply silanes） to the problems of the metal finishing industry. The ultimate goal of this work is the replacement of chromate passivation and paint pretreatments, as well as overcoming the shortcomings of organic coatings formulated in the modern environmentally friendly world, thus without chromate or chromated pigments, volatile organic carbon （VOC） containing compounds or harazardous air pollutants （HAPs）.
基金Project supported by the National Natural Science Foundation of China (Nos. 30471378, 90202010 and 30211130504)the Applied and Basic Research Program of Sichuan Province, and the Talent-Recruiting Program of Sichuan Agricultural University
文摘Macronutrients （N, P, K, Ca, Mg, and S） in litter of three primarily spruce （Picea purpurea Masters） （SF）, fir （Abies faxoniana Rehder ＆ E. H. Wilson） （FF）, and birch （Betula platyphylla Sukaczev） （BF） subalpine forests in western China were measured to understand the monthly variations in litter nutrient concentrations and annual and monthly nutrient returns via litteffall. Nutrient concentration in litter showed the rank order of Ca 〉 N 〉 Mg 〉 K 〉 S 〉 P. Monthly variations in nutrient concentrations were greater in leaf litter （LL） than other litter components. The highest and lowest concentrations of N, P, K, and S in LL were found in the growing season and the nongrowing season, respectively, but Ca and Mg were the opposite. Nutrient returns via litterfall showed a marked monthly pattern with a major peak in October and one or two small peaks in February and/or May, varying with the element and stand type, but no marked monthly variations in nutrient returns via woody litter, reproductive litter, except in May for the BF, and moss litter. Not only litter production but also nutrient concentration controlled the annual nutrient return and the monthly nutrient return pattern. The monthly patterns of the nutrient concentration and return were of ecological importance for nutrient cycling and plant growth in the subalpine forest ecosystems.
文摘AIM:To study the clinical efficacy and safety of Fecal microbiota transplantation(FMT).We systematically reviewed FMT used as clinical therapy.METHODS:We searched MEDLINE,EMBASE,the Cochrane Library and Conference proceedings from inception to July,2013.Treatment effect of FMT was calculated as the percentage of patients who achieved clinical improvement per patient category,on an intention-to-treat basis.RESULTS:We included 45 studies;34 on Clostridium difficile-infection(CDI),7 on inflammatory bowel disease,1 on metabolic syndrome,1 on constipation,1 on pouchitis and 1 on irritable bowel syndrome(IBS).In CDI 90% resolution of diarrhea in 33 case series(n = 867) was reported,and 94% resolution of diarrhea after repeated FMT in a randomized controlled trial(RCT)(n = 16).In ulcerative colitis(UC) remission rates of 0% to 68% were found(n = 106).In Crohn's disease(CD)(n = 6),no benefit was observed.In IBS,70% improvement of symptoms was found(n = 13).100% Reversal of symptoms was observed in constipation(n = 3).In pouchitis,none of the patients(n = 8) achieved remission.One RCT showed significant improvement of insulin sensitivity in metabolic syndrome(n = 10).Serious adverse events were rare.CONCLUSION:FMT is highly effective in CDI,and holds promise in UC.As for CD,chronic constipation,pouchitis and IBS data are too limited to draw conclusions.FMT increases insulin sensitivity in metabolic syndrome.
基金Supported by the Program for New Century Excellent Talents in University of China under Grant No.NCET-05-0657(新世纪优秀人才支持计划)the Foundation for Distinguished Young Scientists of Hubei Province of China under Grant No.2006ABB028(湖北省青年杰出人才基金)
文摘Although suppressed serum testosterone （T） is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual （e.g., erectile dysfunction）, physical （e.g. loss of vigor and frailty） and psychological （e.g., depression） symptoms. This syndrome carries many names, including male menopause or climacterium, andropause and partial androgen deficiency of the ageing male （PADAM）. Late-onset hypogonadism （LOH） describes it best and is therefore generally preferred. The decrease of T in LOH is often marginal, and hypogonadism can be either due to primary testicular failure （low T, high luteinizing hormone （LH）） or secondary to a hypothalamic-pituitary failure （low T, low or inappropriately normal LH）. The latter form is more common and it is usually associated with overweight/obesity or chronic diseases （e.g., type 2 diabetes mellitus, the metabolic syndrome, cardiovascular and chronic obstructive pulmonary disease, and frailty）. A problem with the diagnosis of LOH is that often the symptoms （in 20%-40% of unselected men） and low circulating T （in 20% of men 〉70 years of age） do not coincide in the same individual. The European Male Ageing Study （EMAS） has recently defined the strict diagnostic criteria for LOH to include the simultaneous presence of reproducibly low serum T （total T 〈11 nmol 1-1 and free T 〈220 pmol 1-1） and three sexual symptoms （erectile dysfunction, and reduced frequency of sexual thoughts and morning erections）. By these criteria, only 2% of 40- to 80-year-old men have LOH. In particular obesity, but also impaired general health, are more common causes of low T than chronological age per se. Evidence-based information whether, and how, LOH should be treated is sparse. The most logical approach is lifestyle modification, weight reduction and good treatment of comorbid diseases. T replacement is widely used for the treatment, but evidence-based information about its real benefits
文摘Hepatocellular carcinoma(HCC),the most common primary liver cancer,is one of the dreaded complications of chronic liver disease.Recent experimental and clinical studies have revealed that the alteration of gut-liver axis plays a pivotal role in the onset of chronic liver diseases,including HCC.Altered gut microbiota and endotoxemia are increasingly recognized as critical components in promoting the progression of chronic liver diseases to HCC.Probiotics have been suggested as a novel,safe and cost-effective approach to prevent or treat HCC.Mechanisms by which probiotics exerts their anti-cancer effects include their ability to bind carcinogens,modulation of gut microbiota,improvement of intestinal barrier function,and immunomodulation.This review summarizes the literature findings of the changes in gut microbiota linked to HCC,and discusses the possible therapeutic implications of probiotics for HCC.
文摘Systemic inflammation is a marker of poor prognosis preoperatively present in around 20%-40%of colorectal cancer patients.The hallmarks of systemic inflammation include an increased production of proinflammatory cytokines and acute phase proteins that enter the circulation.While the low-level systemic inflammation is often clinically silent,its consequences are many and may ultimately lead to chronic cancer-associated wasting,cachexia.In this review,we discuss the pathogenesis of cancer-related systemic inflammation,explore the role of systemic inflammation in promoting cancer growth,escaping antitumor defense,and shifting metabolic pathways,and how these changes are related to less favorable outcome.
基金Supported by The Finnish Funding Agency for Technologyand Innovation,Tekes,grants No.945/401/00 and 40160/05the Finnish Graduate School of Applied Biosciences,the Academy of Finland,Grant No.214 157the Centre of Excellence on Microbial Food Safety Research,Academy of Finland
文摘AIM:To study whether selected bacterial 16S ribosomal RNA(rRNA)gene phylotypes are capable of disting- uishing irritable bowel syndrome(IBS). METHODS:The faecal microbiota of twenty volunteers with IBS,subdivided into eight diarrhoea-predominant (IBS-D),eight constipation-predominant(IBS-C)and four mixed symptom-subtype(IBS-M)IBS patients,and fifteen control subjects,were analysed at three time-points with a set of fourteen quantitative real-timepolymerase chain reaction assays.All assays targeted 16S rRNA gene phylotypes putatively associated with IBS,based on 16S rRNA gene library sequence analysis. The target phylotypes were affiliated with Actinobac-teria,Bacteroidetes and Firmicutes.Eight of the target phylotypes had less than 95%similarity to cultured bacterial species according to their 16S rRNA gene sequence.The data analyses were made with repeated-measures ANCOVA-type modelling of the data and principle component analysis(PCA)with linear mixed-effects models applied to the principal component scores. RESULTS:Bacterial phylotypes Clostridium cocleatum 88%,Clostridium thermosuccinogenes 85%,Coprobacillus catenaformis 91%,Ruminococcus bromii-like, Ruminococcus torques 91%,and R.torques 93%were detected from all samples analysed.A multivariate analysis of the relative quantities of all 14 bacterial 16S rRNA gene phylotypes suggested that the intestinal microbiota of the IBS-D patients differed from other sample groups.The PCA on the first principal component(PC1),explaining 30.36%of the observed variation in the IBS-D patient group,was significantly altered from all other sample groups(IBS-D vs control, P=0.01;IBS-D vs IBS-M,P=0.00;IBS-D vs IBS-C, P=0.05).Significant differences were also observed in the levels of distinct phylotypes using relative values in proportion to the total amount of bacteria.A phy- lotype with 85%similarity to C.thermosuccinogenes was quantified in significantly different quantities among the IBS-D and control subjects(-4.08±0.90 vs -3.33±1.16,P=0.04)and IBS-D and IBS-M subjects
文摘AIM： To characterize the bifidobacterial microbiota of the colonic mucosa in patients with colon cancer, inflammatory bowel disease or diverticulitis. METHODS： A sample of the distal colonic mucosa was taken during surgery from a total of 34 patients, twenty-one with diagnosed colorectal cancer, nine with diverticulitis and four with inflammatory bowel disease, requiring surgery for their condition. Bacterial DNA was extracted from the resected mucosal samples and bifidobacterial mucosa-associated microbiota was qualitatively and quantitatively determined by means of qualitative and quantitative PCR. RESULTS： Bifidobacteria were found in 100% of the samples from patients with diverticulitis or IBD and a 76% of those suffering colon cancer. The species B. Iongum and B. bifidum were the most widely found, followed by B. animalis, B. catenulatum and B. adolescentis. B. breve, B. dentium and B. angulatum were not detected in any sample. A significantly higher occurrence of B. Iongum was observed in patients with diverticulitis than in those with colon cancer or IBD （100%, 62% and 75%, respectively, P 〈 0.05）. Similar results were obtained for B, animalis （56%, 0% and 25%, P 〈 0.05）, while B. adolescentis was only found in the mucosa from patients with colon cancer （5 out of 21, 24%）. At the quantitative level, patients with colon cancer or IBD showed lower counts of total Bifidobacterium （4.94 and 5.91 vs 6.96 log Cells/sample, respectively, P 〈 0.05） and of the species B. longum （4.05 and 4.79 vs 6.76, P 〈 0.05） than those with diverticulitis.CONCLUSION： Aberrancies in mucosa associated microbiota are present in different intestinal diseases. This may indicate a role of the microbiota in the pathogenesis of these diseases.
基金the support from an Empa interal research grant.
文摘Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species,the insulating nature of sulfur,and the fast capacity decay of the electrodes.Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites,as well as modifying the separators to physically/chemically retard the polysulfides migration.Two dimensional transition metal carbides,carbonitrides and nitrides,so-called MXenes,are ideal for confining the polysulfides shuttling effects due to their high conductivity,layered structure as well as rich surface terminations.As such,MXenes have thus been widely studied in Li-S batteries,focusing on the conductive sulfur hosts,polysulfides interfaces,and separators.Therefore,in this review,we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail.In addition,challenges and perspectives of MXenes for Li-S batteries are also outlined.
文摘Probiotic bacteria have well-established beneficial ef-fects in the management of diarrhoeal diseases.Newer evidence suggests that probiotics have the potential to reduce the risk of developing inflammatory bowel diseases and intestinal bacterial overgrowth after gut surgery.In liver health,the main benefits of probiotics might occur through preventing the production and/or uptake of lipopolysaccharides in the gut,and therefore reducing levels of low-grade inflammation.Specific immune stimulation by probiotics through processes involving dendritic cells might also be beneficial to the host immunological status and help prevent pathogen translocation.Hepatic fat metabolism also seems to be influenced by the presence of commensal bacteria,and potentially by probiotics;although the mechanisms by which probiotic might act on the liver are still unclear.However,this might be of major importance in the fu-ture because low-grade inflammation,hepatic fat infil-tration,and hepatitis might become more prevalent as a result of high fat intake and the increased prevalence of obesity.
