Fungal and mycotoxin contamination has been found in fordstuffs from Cixian County, an area with a high incidence of esophageal carcinoma (Eca). To set a scientific foundation for the prevention of Eca at the etiologi...Fungal and mycotoxin contamination has been found in fordstuffs from Cixian County, an area with a high incidence of esophageal carcinoma (Eca). To set a scientific foundation for the prevention of Eca at the etiological level, fungal and mycotoxin contaminations of local foodstuffs in Cixian County were analyzed using classical fungal culture methods and HPLC. From 1990 to 1994, 220 corn/wheat samples and 34 corn samples were studied. As a control, 26 corn samples collected from a relatively low incidence area of Eca in Zanhuang County were analyzed for mycotoxins in 1990. The results showed that fungal contamination in corn and wheat was severe and that several of the predominant contaminating fungi such as Furasium moniliforme, etc. were carcinogenic. HPLC results showed that the detection rate and mean content of the mycotoxin sterigmatocystin (ST) in the mountainous area (5/8; 9. 14 μg/kg) were significantly higher than those in the hilly (0; 0) and plain areas (1/18; 1. 29 μg/kg) as well as in low risk area control samples (3/26; 0. 76 μg/kg). Detection rates of deoxynivalenol (DON) in mountainous and hilly areas (5/8, 4/8 respectively) were slightly higher than that in plain area (8/18), while the mean content of DON in the plain area was significantly higher (90. 45-170. 22 vs 50. 56 and 46. 45 μg/kg).Among the different aflatoxins, AFB1 was detected in samples from the two villages in the plain area for the subsequent two years. The mean content of AFB1 was 0. 0183μg/kg, and the highest level was 0. 0497 μg/kg. No AFB1 was detected in the samples from mountainous and hilly areas. AFG1 was detected in more than half of all the samples, and its concentration ranged from 8. 77 to 46. 51 ng/kg. No AFG2 was found in the samples. Thus, the results suggest that at present, fungal and mycotoxin contamination of foodstuffs in Cixian County are quite common.展开更多
Owing to their very high theoretical capacity, lithium （Li） metal anodes regain widespread attentions for their promising applications for next-generation high-energy-density Li batteries （e.g., lithium-sulfur batt...Owing to their very high theoretical capacity, lithium （Li） metal anodes regain widespread attentions for their promising applications for next-generation high-energy-density Li batteries （e.g., lithium-sulfur batteries, lithium-oxygen batteries, solid-state lithium metal batter- ies）. However, the inherent bottleneck of Li metal anodes, especially the growth of Li dendrites and the related safety concerns, should be well addressed. Owing to their featured micro-/nano-porous structures and intriguing physical properties, nanocarbon materials have been applied as host materials for Li metal anodes. This review summarizes the recent progress in the development of porous nanocarbon materials for safe Li metal anodes. The perspectives regarding the challenges and future development of employing micro-/nano-porous carbon materials in Li metal anodes are also included.展开更多
Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure （SCEP...Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure （SCEP）, inductively coupled plasma mass spectrometry （ICP-MS）, X-ray powder diffraction （XRD）, and scanning electron microscope in conjunction with an energy-dispersive X-ray spectrometer （SEM-EDX） analysis. The results indicate that the Li contents have reached the industrial grade of the coal associated Li deposit, and the total Li reserves have reached 2406600 tons, that is, 5157000 tons Li2O in the No. 6 seam in the Jungar Coalfield. The sequential chemical extraction procedure results suggest that the Li concentration is mainly related to inorganic matter. The minerals in the coals consist of kaolinite, boehmite, chlorite-group mineral, quartz, calcite, pyrite, siderite and amorphous clay material. Some Li could be absorbed by clay minerals in the Li-bearing coal seam. The chlorite phase？could be？most likely the host for a part of Li. The Yinshan Oldland should be the most possible source of Li of the coal.展开更多
大红柳滩岩体位于西昆仑造山带东段,主要由黑云母二长花岗岩、二长花岗岩及二云母花岗岩组成。笔者对大红柳滩岩体东南部的黑云母二长花岗岩进行了锆石LA ICP MS U Pb定年,测得黑云母二长花岗岩的侵位年龄分别为(214±1.8)Ma,说明...大红柳滩岩体位于西昆仑造山带东段,主要由黑云母二长花岗岩、二长花岗岩及二云母花岗岩组成。笔者对大红柳滩岩体东南部的黑云母二长花岗岩进行了锆石LA ICP MS U Pb定年,测得黑云母二长花岗岩的侵位年龄分别为(214±1.8)Ma,说明大红柳滩岩体为印支晚期岩浆活动的产物。大红柳滩岩体具有高δ7 Li(0.76‰~3.25‰)和低Li(5.04×10-6~52.22×10-6)同位素地球化学特征;黑云母二长花岗岩样品的锆石εHf(t)值介于-1.86~2.16,二阶段模式年龄为1113~1368 Ma;在εHf(t)锆石U Pb年龄图解中,所有数据点均落在球粒陨石演化线附近。综合研究表明,大红柳滩岩体的原始岩浆是由地幔与中元古代地壳2个单元形成的混合岩浆。展开更多
Chronic inflammation is often associated with alcoholrelated medical conditions. The key inducer of such inflammation, and also the best understood, is gut microflora-derived lipopolysaccharide (LPS). Alcohol can sign...Chronic inflammation is often associated with alcoholrelated medical conditions. The key inducer of such inflammation, and also the best understood, is gut microflora-derived lipopolysaccharide (LPS). Alcohol can significantly increase the translocation of LPS from the gut. In healthy individuals, the adverse effects of LPS are kept in check by the actions and interactions of multiple organs. The liver plays a central role in detoxifying LPS and producing a balanced cytokine milieu. The central nervous system contributes to anti-inflammatory regulation through neuroimmunoendocrine actions. Chronic alcohol use impairs not only gut and liver functions, but also multi-organ interactions, leading to persistent systemic inflammation and ultimately, to organ damage. The study of these interactions may provide potential new targets for therapeutic intervention.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
Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properti...Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properties of a carbon-sulfur composite, in which sulfur is impregnated in porous hollow carbon spheres （PHCSs） via a melt-diffusion method. Instrumental analysis shows that the PHCSs, which were prepared by a facile template strategy, are characterized by high specific surface area （1520 m2.g 1）, large pore volume （2.61 cm^3·g^-1）, broad pore size distribution from micropores to mesopores, and high electronic conductivity （2.22 S·cm-1）. The carbon-sulfur composite with a sulfur content of 50.2 wt.% displays an initial discharge capacity of 1450 mA.h·g^-1 （which is 86.6% of the theoretical specific capacity） and a reversible discharge capacity of 1357 mA.h·g^-1 after 50 cycles at 0.05 C charge-discharge rate. At a higher rate of 0.5 C, the capacity stabilized at around 800 mA-h·g^-1 after 30 cycles. The results illustrate that the porous carbon-sulfur composites with hierarchically porous structure have potential application as the cathode of Li-S batteries because of their effective improvement of the electronic conductivity, the repression of the volume expansion, and the reduction of the shuttling loss.展开更多
This review is part one of three, which will present an update on diagnostic procedures for gastrointestinal (GI) submucosal tumors (SMTs). Part two identifies the classification and part three the therapeutic methods...This review is part one of three, which will present an update on diagnostic procedures for gastrointestinal (GI) submucosal tumors (SMTs). Part two identifies the classification and part three the therapeutic methods regarding GI SMTs. Submucosal tumors are typically asymptomatic and therefore encountered incidentally. Advances in diagnostic tools for gastrointestinal submucosal tumors have emerged over the past decade. The aim of this paper is to provide the readers with guidelines for the use of diagnostic procedures, when a submucosal tumor is suspected. Literature searches were performed to find information on diagnostics for gastrointestinal submucosal tumors. Based on the searches, the optimal diagnostic procedures and specific features of the submucosal tumors could be outlined. Standard endoscppy, capsule endoscopy and push-and-pull enteroscopy (PPE) together with barium contrast X-ray do not alone provide sufficient information, when examining submucosal tumors. Endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI) and fluorodeoxyglucose-labeled positron emission tomography (FDG-PET) are recommended as supplementary tools.展开更多
The aging behaviors of Al 1.42%Li 2.41%Cu 0.93%Mg 0.073%Zr 0.17%Sc(mass fraction, the same below) alloy at room temperature, 160 ℃ , and 160 ℃ after 8% pre deformation were studied respectively by hardness measureme...The aging behaviors of Al 1.42%Li 2.41%Cu 0.93%Mg 0.073%Zr 0.17%Sc(mass fraction, the same below) alloy at room temperature, 160 ℃ , and 160 ℃ after 8% pre deformation were studied respectively by hardness measurement. The microstructure of the alloy in various aging conditions was observed by TEM. The results show that the main precipitations of the alloy in quenching condition are the particles containing Sc and Zr which have certain coherent relation with the matrix. Addition of Sc in Al Li Cu Mg Zr alloy will be favorable to promoting precipitation. The particles can serve as preferred nucleation sites for δ′ phases which accelerate the aging hardening rate at initial aging. The main hardening phases of the alloy aged at 160 ℃ are δ′ and δ′/β′ composite precipitates. The size of the composite precipitates is very small (nanometer size). The composite precipitates will preclude efficiently the formation concentrative slip location and will improve the mechanical properties of the alloy. S′ phase will occur in the alloy aged at 160 ℃ after 8% pre deformation. It is found that 8% pre deformation has no obvious influence on the precipitation of the composite phase.展开更多
文摘Fungal and mycotoxin contamination has been found in fordstuffs from Cixian County, an area with a high incidence of esophageal carcinoma (Eca). To set a scientific foundation for the prevention of Eca at the etiological level, fungal and mycotoxin contaminations of local foodstuffs in Cixian County were analyzed using classical fungal culture methods and HPLC. From 1990 to 1994, 220 corn/wheat samples and 34 corn samples were studied. As a control, 26 corn samples collected from a relatively low incidence area of Eca in Zanhuang County were analyzed for mycotoxins in 1990. The results showed that fungal contamination in corn and wheat was severe and that several of the predominant contaminating fungi such as Furasium moniliforme, etc. were carcinogenic. HPLC results showed that the detection rate and mean content of the mycotoxin sterigmatocystin (ST) in the mountainous area (5/8; 9. 14 μg/kg) were significantly higher than those in the hilly (0; 0) and plain areas (1/18; 1. 29 μg/kg) as well as in low risk area control samples (3/26; 0. 76 μg/kg). Detection rates of deoxynivalenol (DON) in mountainous and hilly areas (5/8, 4/8 respectively) were slightly higher than that in plain area (8/18), while the mean content of DON in the plain area was significantly higher (90. 45-170. 22 vs 50. 56 and 46. 45 μg/kg).Among the different aflatoxins, AFB1 was detected in samples from the two villages in the plain area for the subsequent two years. The mean content of AFB1 was 0. 0183μg/kg, and the highest level was 0. 0497 μg/kg. No AFB1 was detected in the samples from mountainous and hilly areas. AFG1 was detected in more than half of all the samples, and its concentration ranged from 8. 77 to 46. 51 ng/kg. No AFG2 was found in the samples. Thus, the results suggest that at present, fungal and mycotoxin contamination of foodstuffs in Cixian County are quite common.
基金financially supported by the National Key Research and Development Program(Nos.2016YFA0202500,2015CB932500)the National Natural Scientific Foundation of China(Nos.21676160,21561130151)
文摘Owing to their very high theoretical capacity, lithium （Li） metal anodes regain widespread attentions for their promising applications for next-generation high-energy-density Li batteries （e.g., lithium-sulfur batteries, lithium-oxygen batteries, solid-state lithium metal batter- ies）. However, the inherent bottleneck of Li metal anodes, especially the growth of Li dendrites and the related safety concerns, should be well addressed. Owing to their featured micro-/nano-porous structures and intriguing physical properties, nanocarbon materials have been applied as host materials for Li metal anodes. This review summarizes the recent progress in the development of porous nanocarbon materials for safe Li metal anodes. The perspectives regarding the challenges and future development of employing micro-/nano-porous carbon materials in Li metal anodes are also included.
基金financially supported by the National Science Fundamental of China Projects(Nos.41072115 and 51174262)the project of the Science Foundation of Hebei(No.D2011402034)
文摘Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure （SCEP）, inductively coupled plasma mass spectrometry （ICP-MS）, X-ray powder diffraction （XRD）, and scanning electron microscope in conjunction with an energy-dispersive X-ray spectrometer （SEM-EDX） analysis. The results indicate that the Li contents have reached the industrial grade of the coal associated Li deposit, and the total Li reserves have reached 2406600 tons, that is, 5157000 tons Li2O in the No. 6 seam in the Jungar Coalfield. The sequential chemical extraction procedure results suggest that the Li concentration is mainly related to inorganic matter. The minerals in the coals consist of kaolinite, boehmite, chlorite-group mineral, quartz, calcite, pyrite, siderite and amorphous clay material. Some Li could be absorbed by clay minerals in the Li-bearing coal seam. The chlorite phase？could be？most likely the host for a part of Li. The Yinshan Oldland should be the most possible source of Li of the coal.
文摘大红柳滩岩体位于西昆仑造山带东段,主要由黑云母二长花岗岩、二长花岗岩及二云母花岗岩组成。笔者对大红柳滩岩体东南部的黑云母二长花岗岩进行了锆石LA ICP MS U Pb定年,测得黑云母二长花岗岩的侵位年龄分别为(214±1.8)Ma,说明大红柳滩岩体为印支晚期岩浆活动的产物。大红柳滩岩体具有高δ7 Li(0.76‰~3.25‰)和低Li(5.04×10-6~52.22×10-6)同位素地球化学特征;黑云母二长花岗岩样品的锆石εHf(t)值介于-1.86~2.16,二阶段模式年龄为1113~1368 Ma;在εHf(t)锆石U Pb年龄图解中,所有数据点均落在球粒陨石演化线附近。综合研究表明,大红柳滩岩体的原始岩浆是由地幔与中元古代地壳2个单元形成的混合岩浆。
文摘Chronic inflammation is often associated with alcoholrelated medical conditions. The key inducer of such inflammation, and also the best understood, is gut microflora-derived lipopolysaccharide (LPS). Alcohol can significantly increase the translocation of LPS from the gut. In healthy individuals, the adverse effects of LPS are kept in check by the actions and interactions of multiple organs. The liver plays a central role in detoxifying LPS and producing a balanced cytokine milieu. The central nervous system contributes to anti-inflammatory regulation through neuroimmunoendocrine actions. Chronic alcohol use impairs not only gut and liver functions, but also multi-organ interactions, leading to persistent systemic inflammation and ultimately, to organ damage. The study of these interactions may provide potential new targets for therapeutic intervention.
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Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properties of a carbon-sulfur composite, in which sulfur is impregnated in porous hollow carbon spheres （PHCSs） via a melt-diffusion method. Instrumental analysis shows that the PHCSs, which were prepared by a facile template strategy, are characterized by high specific surface area （1520 m2.g 1）, large pore volume （2.61 cm^3·g^-1）, broad pore size distribution from micropores to mesopores, and high electronic conductivity （2.22 S·cm-1）. The carbon-sulfur composite with a sulfur content of 50.2 wt.% displays an initial discharge capacity of 1450 mA.h·g^-1 （which is 86.6% of the theoretical specific capacity） and a reversible discharge capacity of 1357 mA.h·g^-1 after 50 cycles at 0.05 C charge-discharge rate. At a higher rate of 0.5 C, the capacity stabilized at around 800 mA-h·g^-1 after 30 cycles. The results illustrate that the porous carbon-sulfur composites with hierarchically porous structure have potential application as the cathode of Li-S batteries because of their effective improvement of the electronic conductivity, the repression of the volume expansion, and the reduction of the shuttling loss.
文摘This review is part one of three, which will present an update on diagnostic procedures for gastrointestinal (GI) submucosal tumors (SMTs). Part two identifies the classification and part three the therapeutic methods regarding GI SMTs. Submucosal tumors are typically asymptomatic and therefore encountered incidentally. Advances in diagnostic tools for gastrointestinal submucosal tumors have emerged over the past decade. The aim of this paper is to provide the readers with guidelines for the use of diagnostic procedures, when a submucosal tumor is suspected. Literature searches were performed to find information on diagnostics for gastrointestinal submucosal tumors. Based on the searches, the optimal diagnostic procedures and specific features of the submucosal tumors could be outlined. Standard endoscppy, capsule endoscopy and push-and-pull enteroscopy (PPE) together with barium contrast X-ray do not alone provide sufficient information, when examining submucosal tumors. Endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI) and fluorodeoxyglucose-labeled positron emission tomography (FDG-PET) are recommended as supplementary tools.
基金The Key Program of the 9th Five year Plan of China!(No .95 YS 0 0 1)
文摘The aging behaviors of Al 1.42%Li 2.41%Cu 0.93%Mg 0.073%Zr 0.17%Sc(mass fraction, the same below) alloy at room temperature, 160 ℃ , and 160 ℃ after 8% pre deformation were studied respectively by hardness measurement. The microstructure of the alloy in various aging conditions was observed by TEM. The results show that the main precipitations of the alloy in quenching condition are the particles containing Sc and Zr which have certain coherent relation with the matrix. Addition of Sc in Al Li Cu Mg Zr alloy will be favorable to promoting precipitation. The particles can serve as preferred nucleation sites for δ′ phases which accelerate the aging hardening rate at initial aging. The main hardening phases of the alloy aged at 160 ℃ are δ′ and δ′/β′ composite precipitates. The size of the composite precipitates is very small (nanometer size). The composite precipitates will preclude efficiently the formation concentrative slip location and will improve the mechanical properties of the alloy. S′ phase will occur in the alloy aged at 160 ℃ after 8% pre deformation. It is found that 8% pre deformation has no obvious influence on the precipitation of the composite phase.
