目的了解上海地区男男性行为人群(Men who have sex with men,MSM)拥有性伴情况及性行为特征,探讨性病、艾滋病病毒(Human immunodeficiency virus,HIV)在该人群中的传播及其向普通人群传播的途径,为制定性病、艾滋病预防控制策略提供...目的了解上海地区男男性行为人群(Men who have sex with men,MSM)拥有性伴情况及性行为特征,探讨性病、艾滋病病毒(Human immunodeficiency virus,HIV)在该人群中的传播及其向普通人群传播的途径,为制定性病、艾滋病预防控制策略提供依据。方法通过艾滋病自愿咨询检测门诊、网络、非政府组织、"滚雪球"等方式招募MSM对象,采用面对面匿名问卷调查方式收集相关信息。结果共招募了459名MSM,发现最近6个月内有64人(13.9%)与女性性伴发生过性行为,其中危险性行为的发生率为51.6%;最近6个月内有318人(69.3%)曾主动寻求与男性发生性行为,主要寻找途径是通过网络,占73.3%。最近6个月同性性伴数最少1个,最多50个,中位数2个。其中174人(64.4%)有同性固定性伴,223人(48.6%)与非同性固定性伴发生过多次男男性行为(4N9),236人(51.4%)发生过一夜情(419),28人(6.6%)从事商业性性行为。而在与固定同性性伴、同性4N9、同性419、商业性男性客人的高危性行为发生率,依次是64.4%、56.1%、52.5%、64.3%。结论 MSM人群属于性活跃人群,拥有性伴类型复杂多样,高危性行为发生率高,使HIV及性病在该人群中广泛传播,尤其与女性性伴发生高危性行为比例较高,今后与女性结婚可能性较大,使其已成为向普通人群传播HIV的"桥梁人群"。应积极在该人群中开展干预工作。展开更多
AIM:To investigate the epidemiological characteristics of colorectal cancer(CRC)in patients under 50 years of age across two institutions.METHODS:Records of patients under age 50 years of age who had CRC surgery over ...AIM:To investigate the epidemiological characteristics of colorectal cancer(CRC)in patients under 50 years of age across two institutions.METHODS:Records of patients under age 50 years of age who had CRC surgery over a 16 year period were assessed at two institutions.The following documents where reviewed:admission notes,operative notes,and discharge summaries.The main study variables included:age,presenting symptoms,family history,tumor location,operation,stage/differentiation of disease,and post operative complications.Stage of disease was classified according to the American Joint Committee on Cancer TNM staging system:tumor depth;node status;and metastases.RESULTS:CRC was found in 180 patients under age50 years(87 females,93 males;mean age 41.4±6.2years).Young patients accounted for 11.2%of cases during a 6 year period for which the full data set wasavailable.Eight percent had a 1stdegree and 12%a 2nd degree family CRC history.Almost all patients(94%)were symptomatic at diagnosis;common symptoms included:bleeding(59%),obstruction(9%),and abdominal/rectal pain(35%).Evaluation was often delayed and bleeding frequently attributed to hemorrhoids.Advanced stage CRC(Stage 3 or 4)was noted in 53%of patients.Most tumors were distal to the splenic flexure(77%)and 39%involved the rectum.Most patients(95%)had segmental resections;6 patients had subtotal/total colectomy.Poorly differentiated tumors were noted in 12%and mucinous lesions in 19%of patients of which most had Stage 3 or 4 disease.Twenty-two patients(13%)developed recurrence and/or progression of disease to date.Three patients(ages 42,42and 49 years)went on to develop metachronous primary colon cancers within 3 to 4 years of their initial resection.CONCLUSION:CRC was common in young patients with no family history.Young patients with symptoms merit a timely evaluation to avoid presentation with late stage CRC.展开更多
Carbon capture,utilization and storage (CCUS) is considered as a very important technology for mitigating global climate change.Carbon dioxide (CO2) injected into an underground reservoir will induce changes in its ph...Carbon capture,utilization and storage (CCUS) is considered as a very important technology for mitigating global climate change.Carbon dioxide (CO2) injected into an underground reservoir will induce changes in its physical properties and the migration of CO2 will be affected by many factors.Accurately understanding these changes and migration characteristics of CO2 is crucial for selecting a CCUS project site,estimating storage capacity and ensuring storage security.In this paper,the basic principles of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) technologies are briefly introduced in the context of laboratory experiments related to CCUS.The types of NMR apparatus,experimental samples and testing approaches applied worldwide are discussed and analyzed.Then two typical NMR core analysis systems used in CCUS field and a self-developed high-pressure,low-field NMR rock core flooding experimental system are compared.Finally,a summary of the current deficiencies related to NMR applied to CCUS field is given and future research plans are proposed.展开更多
The aim of this review is to offer dietary advice for individuals with spinal cord injury(SCI)and neurogenic bowel dysfunction.With this in mind,we consider health conditions that are dependent on the level of lesion ...The aim of this review is to offer dietary advice for individuals with spinal cord injury(SCI)and neurogenic bowel dysfunction.With this in mind,we consider health conditions that are dependent on the level of lesion including skeletal muscle atrophy,autonomic dysreflexia and neurogenic bladder.In addition,SCI is often associated with a sedentary lifestyle,which increases risk for osteoporosis and diseases associated with chronic low-grade inflammation,including cardiovascular and chronic kidney diseases.The Mediterranean diet,along with exercise and dietary supplements,has been suggested as an anti-inflammatory intervention in individuals with SCI.However,individuals with chronic SCI have a daily intake of whole fruit,vegetables and whole grains lower than the recommended dietary allowance for the general population.Some studies have reported an increase in neurogenic bowel dysfunction symptoms after high fiber intake;therefore,this finding could explain the low consumption of plant foods.Low consumption of fibre induces dysbiosis,which is associated with bothendotoxemia and inflammation.Dysbiosis can be reduced by exercise and diet in individuals with SCI.Therefore,to summarize our viewpoint,we developed a Mediterranean diet-based diet and exercise pyramid to integrate nutritional recommendations and exercise guidelines.Nutritional guidelines come from previously suggested recommendations for military veterans with disabilities and individuals with SCI,chronic kidney diseases,chronic pain and irritable bowel syndrome.We also considered the recent exercise guidelines and position stands for adults with SCI to improve muscle strength,flexibility and cardiorespiratory fitness and to obtain cardiometabolic benefits.Finally,dietary advice for Paralympic athletes is suggested.展开更多
[目的]了解男男性行为者（men who have sex with men,MSM）人群社会网络及性行为特征,为MSM人群干预提供参考。[方法]采用统一设计的问卷进行面对面调查,并用描述性、卡方检验等方法进行分析。[结果]151名被调查对象拥有128个社交网络...[目的]了解男男性行为者（men who have sex with men,MSM）人群社会网络及性行为特征,为MSM人群干预提供参考。[方法]采用统一设计的问卷进行面对面调查,并用描述性、卡方检验等方法进行分析。[结果]151名被调查对象拥有128个社交网络;网络大小为2~6个节点,其中≥4个节点的占32.93%;网络密度为0.40~1.00,中位数为1.00;社会网络成员中,男性占85.86%,≤30岁者占73.73%,大学及以上文化程度者占49.93%,被调查对象与社交对象年龄、文化程度的构成差异无统计学意义。297名社交对象中,属于朋友或同学者占61.62%,同事占15.15%,性伴占12.12%,亲属占11.11%;56.23%是MSM;24.58%曾与被调查对象发生性行为,其中76.71%在过去6个月发生过性关系。被调查对象首次与男性发生性行为的年龄为13~40岁,平均（22.73±5.14）岁;在过去6个月中,男性伴个数为1~101个,中位数为2个;60.93%有2个以上男性伴,与固定男性伴、多次男性伴、偶遇男性伴、商业男性伴、异性性伴不安全性行为发生率分别为51.65%、46.05%、36.84%、75.00%和53.33%。[结论]MSM人群多性伴、无保护性行为普遍,社会网络是艾滋病危险行为扩散的重要影响因素,应根据各地区网络社交的特点,开展针对性艾滋病防治。展开更多
Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these f...Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these factors depends on tree mycorrhizal associations,whereby large-tree effects may be driven by ectomycorrhizal(EM)trees,diversity effects may be driven by arbuscular mycorrhizal(AM)trees,and environment effects may depend on differential climate and soil preferences of AM and EM trees.To test this hypothesis,we used forest-inventory data consisting of over 80,000 trees from 631 temperate-forest plots(30 m×30 m)across Northeast China to examine how biodiversity(species diversity and ecological uniqueness),large trees(top 1%of tree diameters),and environmental factors(climate and soil nutrients)differently regulate aboveground carbon stocks of AM trees,EM trees,and AM and EM trees combined(i.e.total aboveground carbon stock).We found that large trees had a positive effect on both AM and EM tree carbon stocks.However,biodiversity and environmental factors had opposite effects on AM vs.EM tree carbon stocks.Specifically,the two components of biodiversity had positive effects on AM tree carbon stocks,but negative effects on EM tree carbon stocks.Environmental heterogeneity(mean annual temperature and soil nutrients)also exhibited contrasting effects on AM and EM tree carbon stocks.Consequently,for the total carbon stock,the positive large-tree effect far surpasses the diversity and environment effect.This is mainly because when integrating AM and EM tree carbon stock into total carbon stock,the opposite diversity-effect(also environment-effect)on AM vs.EM tree carbon stock counteracts each other while the consistent positive large-tree effect on AM and EM tree carbon stock is amplified.In summary,this study emphasized a mycorrhizal viewpoint to better understand the determinants of overarching aboveground carbon profile across regional forests.展开更多
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is...To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process.展开更多
We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. Th...We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.展开更多
In order to improve CO_(2) capture,utilization and storage(CCUS) to solve carbon emission,sandstone from the Triassic Liujiagou Formation(LF) from the Ordos Basin in China was investigated using permeability tests and...In order to improve CO_(2) capture,utilization and storage(CCUS) to solve carbon emission,sandstone from the Triassic Liujiagou Formation(LF) from the Ordos Basin in China was investigated using permeability tests and computed X-ray tomography(CT) scanning.The presence of reactive minerals within the geological CO_(2) sequestration target storage formation can allow reaction with injected CO_(2),which changes the porosity and permeability of the LF beds,affecting storage effectiveness.To investigate the effect of chemical reactions on the pore structure and permeability of sandstone cores representing the LF CO_(2) storage,tests were conducted to analyze the changes in porosity and permeability of sandstone cores induced by CO_(2)-saturated brine at different reaction times(28-day maximum reaction period).Porosity and permeability of the sandstone increased after reaction with CO_(2)-saturated brine due to mineral dissolution.The sandstone exhibited an increase in porosity and permeability after 15 days of reaction with CO_(2)-saturated brine.Moreover,there was an increase in the volume of large pores in the sandstone after the 28-day period.The pore network of the sandstone was established through CT results,and the porosity calculated based on the obtained pore network was close to that measured in the test,demonstrating the feasibility to use CT to study the evolution of the microstructure of sandstone after long-time exposure to CO_(2)-saturated brine.展开更多
During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3...During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3 and C4 species to longterm exposure to glacial conditions. Here Abutilon theophrasti Medik. （C3） and Amaranthus retroflexus L. （C4） were grown at 200 umol/mol CO2 with current （30/24℃） and glacial （22/16℃） temperatures for 22d. Overall, the C4 species exhibited a large growth advantage over the C3 species at low [CO2]. However, this advantage was reduced at low temperature, where the C4 species produced 5x the total mass of the C3 species versus 14x at the high temperature. This difference was due to a reduction in C4 growth at low temperature, since the C3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C4 species had a growth advantage over C3 species during low [CO2] of the last ice age, although concurrent reductions in temperatures may have reduced this advantage.展开更多
目的了解上海地区男男性行为人群(Men who have sex with men,MSM)的社会学特征及艾滋病相关的健康需求,分析该人群主动参与艾滋病病毒(Human immunodeficiency virus,HIV)抗体检测的情况,为更好地开展MSM人群艾滋病高危行为干预提供思...目的了解上海地区男男性行为人群(Men who have sex with men,MSM)的社会学特征及艾滋病相关的健康需求,分析该人群主动参与艾滋病病毒(Human immunodeficiency virus,HIV)抗体检测的情况,为更好地开展MSM人群艾滋病高危行为干预提供思路。方法采用横断面调查方法,于2010年对上海地区314名符合入选标准的研究对象进行一对一问卷调查,收集一般人口学信息、性取向与性活动情况、既往接受HIV抗体检测及HIV感染情况等资料,进行相关的统计描述与分析。结果被调查的314名MSM中,68.5%(215/314)为外来人员;其性伙伴为仅男性、男性为主、男女各半及女性为主的分别占64.0%(201/314)、21.7%(68/314)、7.0%(22/314)和7.3%(23/314)。其中既往HIV抗体检测率为73.9%(232/314),最近2年检测率为63.4%(199/314),不参与检测的主要原因是不相信自己会感染。被调查者对目前艾滋病防治工作的建议主要为加强宣传教育,多关心、多理解、少歧视,加强免费安全套推广等。结论上海市MSM人群对艾滋病防治相关的健康干预措施有较高的需求,加强反对歧视的宣传,多关心、多理解MSM人群,推广免费优质安全套等措施能有效满足MSM人群的健康和心理需求,对有效开展艾滋病防治工作具有重要意义。展开更多
Polyreactive innate-type B cells account for many B cells expressing self-reactivity in the periphery. Improper regulation of these B cells may be an important factor that underlies autoimmune disease. Here we have ex...Polyreactive innate-type B cells account for many B cells expressing self-reactivity in the periphery. Improper regulation of these B cells may be an important factor that underlies autoimmune disease. Here we have explored the influence of self-reactive innate B cells in the development of collagen-induced arthritis （CIA）, a mouse model of rheumatoid arthritis. We show that splenic marginal zone （MZ）, but not B- 1 B cells exhibit spontaneous IgM reactivity to autologous collagen II in na＇=＇ve mice. Upon immunization with heterologous collagen II in complete Freund＇s adjuvant the collagen-reactive MZ B cells expanded rapidly, while the B-1 B cells showed a modest anti-collagen response. The MZ B cells were easily activated by toll-like receptor （TLR） 4 and 9-1igands in vitro, inducing proliferation and cytokine secretion, implying that dual engagement of the B-cell receptor and TLRs may promote the immune response to self-antigen. Furthermore, collagen-primed MZ B cells showed significant antigen-presenting capacity as reflected by cognate T-cell proliferation in vitroand induction of IgG anti-collagen antibodies in vivo. MZ B cells that were deficient in complement receptors I and 2 demonstrated increased proliferation and cytokine production, while Fcy receptor lib deficiency of the cells lead to increased cytokine production and antigen presentation. In conclusion, our data highlight self-reactive MZ B cells as initiators of the autoimmune response in CIA, where complement and Fc receptors are relevant in controlling the self-reactivity in the cells.展开更多
文摘目的了解上海地区男男性行为人群(Men who have sex with men,MSM)拥有性伴情况及性行为特征,探讨性病、艾滋病病毒(Human immunodeficiency virus,HIV)在该人群中的传播及其向普通人群传播的途径,为制定性病、艾滋病预防控制策略提供依据。方法通过艾滋病自愿咨询检测门诊、网络、非政府组织、"滚雪球"等方式招募MSM对象,采用面对面匿名问卷调查方式收集相关信息。结果共招募了459名MSM,发现最近6个月内有64人(13.9%)与女性性伴发生过性行为,其中危险性行为的发生率为51.6%;最近6个月内有318人(69.3%)曾主动寻求与男性发生性行为,主要寻找途径是通过网络,占73.3%。最近6个月同性性伴数最少1个,最多50个,中位数2个。其中174人(64.4%)有同性固定性伴,223人(48.6%)与非同性固定性伴发生过多次男男性行为(4N9),236人(51.4%)发生过一夜情(419),28人(6.6%)从事商业性性行为。而在与固定同性性伴、同性4N9、同性419、商业性男性客人的高危性行为发生率,依次是64.4%、56.1%、52.5%、64.3%。结论 MSM人群属于性活跃人群,拥有性伴类型复杂多样,高危性行为发生率高,使HIV及性病在该人群中广泛传播,尤其与女性性伴发生高危性行为比例较高,今后与女性结婚可能性较大,使其已成为向普通人群传播HIV的"桥梁人群"。应积极在该人群中开展干预工作。
文摘AIM:To investigate the epidemiological characteristics of colorectal cancer(CRC)in patients under 50 years of age across two institutions.METHODS:Records of patients under age 50 years of age who had CRC surgery over a 16 year period were assessed at two institutions.The following documents where reviewed:admission notes,operative notes,and discharge summaries.The main study variables included:age,presenting symptoms,family history,tumor location,operation,stage/differentiation of disease,and post operative complications.Stage of disease was classified according to the American Joint Committee on Cancer TNM staging system:tumor depth;node status;and metastases.RESULTS:CRC was found in 180 patients under age50 years(87 females,93 males;mean age 41.4±6.2years).Young patients accounted for 11.2%of cases during a 6 year period for which the full data set wasavailable.Eight percent had a 1stdegree and 12%a 2nd degree family CRC history.Almost all patients(94%)were symptomatic at diagnosis;common symptoms included:bleeding(59%),obstruction(9%),and abdominal/rectal pain(35%).Evaluation was often delayed and bleeding frequently attributed to hemorrhoids.Advanced stage CRC(Stage 3 or 4)was noted in 53%of patients.Most tumors were distal to the splenic flexure(77%)and 39%involved the rectum.Most patients(95%)had segmental resections;6 patients had subtotal/total colectomy.Poorly differentiated tumors were noted in 12%and mucinous lesions in 19%of patients of which most had Stage 3 or 4 disease.Twenty-two patients(13%)developed recurrence and/or progression of disease to date.Three patients(ages 42,42and 49 years)went on to develop metachronous primary colon cancers within 3 to 4 years of their initial resection.CONCLUSION:CRC was common in young patients with no family history.Young patients with symptoms merit a timely evaluation to avoid presentation with late stage CRC.
基金supported by the Open Research Fund of State Key Laboratory of Geomechanics and GeotechnicalEngineering, IRSM, CAS (Grant No. Z017002)the National Natural Science Foundation of China (Grant Nos. 41872210 and 41274111)financial support from the China-Australia Geological Storage of CO_2 (CAGS) Project funded by the Australian Government under the auspices of the China-Australia Joint Coordination Group on Clean Coal Technology
文摘Carbon capture,utilization and storage (CCUS) is considered as a very important technology for mitigating global climate change.Carbon dioxide (CO2) injected into an underground reservoir will induce changes in its physical properties and the migration of CO2 will be affected by many factors.Accurately understanding these changes and migration characteristics of CO2 is crucial for selecting a CCUS project site,estimating storage capacity and ensuring storage security.In this paper,the basic principles of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) technologies are briefly introduced in the context of laboratory experiments related to CCUS.The types of NMR apparatus,experimental samples and testing approaches applied worldwide are discussed and analyzed.Then two typical NMR core analysis systems used in CCUS field and a self-developed high-pressure,low-field NMR rock core flooding experimental system are compared.Finally,a summary of the current deficiencies related to NMR applied to CCUS field is given and future research plans are proposed.
基金Supported by the Project AMAMP(2019-2021),No.M_D GCOM REG2019002167303-12-2019funded by Ministero della Difesa,Italyfunded as a visiting professor by Sapienza,University of Rome,No.Prot.n.008164526-09-2019。
文摘The aim of this review is to offer dietary advice for individuals with spinal cord injury(SCI)and neurogenic bowel dysfunction.With this in mind,we consider health conditions that are dependent on the level of lesion including skeletal muscle atrophy,autonomic dysreflexia and neurogenic bladder.In addition,SCI is often associated with a sedentary lifestyle,which increases risk for osteoporosis and diseases associated with chronic low-grade inflammation,including cardiovascular and chronic kidney diseases.The Mediterranean diet,along with exercise and dietary supplements,has been suggested as an anti-inflammatory intervention in individuals with SCI.However,individuals with chronic SCI have a daily intake of whole fruit,vegetables and whole grains lower than the recommended dietary allowance for the general population.Some studies have reported an increase in neurogenic bowel dysfunction symptoms after high fiber intake;therefore,this finding could explain the low consumption of plant foods.Low consumption of fibre induces dysbiosis,which is associated with bothendotoxemia and inflammation.Dysbiosis can be reduced by exercise and diet in individuals with SCI.Therefore,to summarize our viewpoint,we developed a Mediterranean diet-based diet and exercise pyramid to integrate nutritional recommendations and exercise guidelines.Nutritional guidelines come from previously suggested recommendations for military veterans with disabilities and individuals with SCI,chronic kidney diseases,chronic pain and irritable bowel syndrome.We also considered the recent exercise guidelines and position stands for adults with SCI to improve muscle strength,flexibility and cardiorespiratory fitness and to obtain cardiometabolic benefits.Finally,dietary advice for Paralympic athletes is suggested.
文摘[目的]了解男男性行为者（men who have sex with men,MSM）人群社会网络及性行为特征,为MSM人群干预提供参考。[方法]采用统一设计的问卷进行面对面调查,并用描述性、卡方检验等方法进行分析。[结果]151名被调查对象拥有128个社交网络;网络大小为2~6个节点,其中≥4个节点的占32.93%;网络密度为0.40~1.00,中位数为1.00;社会网络成员中,男性占85.86%,≤30岁者占73.73%,大学及以上文化程度者占49.93%,被调查对象与社交对象年龄、文化程度的构成差异无统计学意义。297名社交对象中,属于朋友或同学者占61.62%,同事占15.15%,性伴占12.12%,亲属占11.11%;56.23%是MSM;24.58%曾与被调查对象发生性行为,其中76.71%在过去6个月发生过性关系。被调查对象首次与男性发生性行为的年龄为13~40岁,平均（22.73±5.14）岁;在过去6个月中,男性伴个数为1~101个,中位数为2个;60.93%有2个以上男性伴,与固定男性伴、多次男性伴、偶遇男性伴、商业男性伴、异性性伴不安全性行为发生率分别为51.65%、46.05%、36.84%、75.00%和53.33%。[结论]MSM人群多性伴、无保护性行为普遍,社会网络是艾滋病危险行为扩散的重要影响因素,应根据各地区网络社交的特点,开展针对性艾滋病防治。
基金supported by the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant ZDBS-LY-DQC019)the National Key Research and Development Program of China(2023YFE0124300)+4 种基金the National Natural Science Foundation of China(32301344)Major Program of Institute of Applied EcologyChinese Academy of Sciences(IAEMP202201)supported by grants from the U.S.National Science Foundation(DEB 2240431)the Seeding Projects for Enabling Excellence and Distinction(SPEED)Program at Washington University in St.Louis。
文摘Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these factors depends on tree mycorrhizal associations,whereby large-tree effects may be driven by ectomycorrhizal(EM)trees,diversity effects may be driven by arbuscular mycorrhizal(AM)trees,and environment effects may depend on differential climate and soil preferences of AM and EM trees.To test this hypothesis,we used forest-inventory data consisting of over 80,000 trees from 631 temperate-forest plots(30 m×30 m)across Northeast China to examine how biodiversity(species diversity and ecological uniqueness),large trees(top 1%of tree diameters),and environmental factors(climate and soil nutrients)differently regulate aboveground carbon stocks of AM trees,EM trees,and AM and EM trees combined(i.e.total aboveground carbon stock).We found that large trees had a positive effect on both AM and EM tree carbon stocks.However,biodiversity and environmental factors had opposite effects on AM vs.EM tree carbon stocks.Specifically,the two components of biodiversity had positive effects on AM tree carbon stocks,but negative effects on EM tree carbon stocks.Environmental heterogeneity(mean annual temperature and soil nutrients)also exhibited contrasting effects on AM and EM tree carbon stocks.Consequently,for the total carbon stock,the positive large-tree effect far surpasses the diversity and environment effect.This is mainly because when integrating AM and EM tree carbon stock into total carbon stock,the opposite diversity-effect(also environment-effect)on AM vs.EM tree carbon stock counteracts each other while the consistent positive large-tree effect on AM and EM tree carbon stock is amplified.In summary,this study emphasized a mycorrhizal viewpoint to better understand the determinants of overarching aboveground carbon profile across regional forests.
基金Financial support provided by Correlated Solutions Incorporated to perform StereoDIC experimentsthe Department of Mechanical Engineering at the University of South Carolina for simulation studies is deeply appreciated.
文摘To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process.
文摘We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.
基金the funding support provided by the National Natural Science Foundation of China (Grant Nos. U1967208 and 42172315)。
文摘In order to improve CO_(2) capture,utilization and storage(CCUS) to solve carbon emission,sandstone from the Triassic Liujiagou Formation(LF) from the Ordos Basin in China was investigated using permeability tests and computed X-ray tomography(CT) scanning.The presence of reactive minerals within the geological CO_(2) sequestration target storage formation can allow reaction with injected CO_(2),which changes the porosity and permeability of the LF beds,affecting storage effectiveness.To investigate the effect of chemical reactions on the pore structure and permeability of sandstone cores representing the LF CO_(2) storage,tests were conducted to analyze the changes in porosity and permeability of sandstone cores induced by CO_(2)-saturated brine at different reaction times(28-day maximum reaction period).Porosity and permeability of the sandstone increased after reaction with CO_(2)-saturated brine due to mineral dissolution.The sandstone exhibited an increase in porosity and permeability after 15 days of reaction with CO_(2)-saturated brine.Moreover,there was an increase in the volume of large pores in the sandstone after the 28-day period.The pore network of the sandstone was established through CT results,and the porosity calculated based on the obtained pore network was close to that measured in the test,demonstrating the feasibility to use CT to study the evolution of the microstructure of sandstone after long-time exposure to CO_(2)-saturated brine.
基金Supported by the US Department of Energy (DE-FG02-95ER62124)the US National Science Foundation (0517668 and 0746822)an American Fellowship to JK Ward from the American Association of University Women Educational Foundation.
文摘During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3 and C4 species to longterm exposure to glacial conditions. Here Abutilon theophrasti Medik. （C3） and Amaranthus retroflexus L. （C4） were grown at 200 umol/mol CO2 with current （30/24℃） and glacial （22/16℃） temperatures for 22d. Overall, the C4 species exhibited a large growth advantage over the C3 species at low [CO2]. However, this advantage was reduced at low temperature, where the C4 species produced 5x the total mass of the C3 species versus 14x at the high temperature. This difference was due to a reduction in C4 growth at low temperature, since the C3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C4 species had a growth advantage over C3 species during low [CO2] of the last ice age, although concurrent reductions in temperatures may have reduced this advantage.
文摘目的了解上海地区男男性行为人群(Men who have sex with men,MSM)的社会学特征及艾滋病相关的健康需求,分析该人群主动参与艾滋病病毒(Human immunodeficiency virus,HIV)抗体检测的情况,为更好地开展MSM人群艾滋病高危行为干预提供思路。方法采用横断面调查方法,于2010年对上海地区314名符合入选标准的研究对象进行一对一问卷调查,收集一般人口学信息、性取向与性活动情况、既往接受HIV抗体检测及HIV感染情况等资料,进行相关的统计描述与分析。结果被调查的314名MSM中,68.5%(215/314)为外来人员;其性伙伴为仅男性、男性为主、男女各半及女性为主的分别占64.0%(201/314)、21.7%(68/314)、7.0%(22/314)和7.3%(23/314)。其中既往HIV抗体检测率为73.9%(232/314),最近2年检测率为63.4%(199/314),不参与检测的主要原因是不相信自己会感染。被调查者对目前艾滋病防治工作的建议主要为加强宣传教育,多关心、多理解、少歧视,加强免费安全套推广等。结论上海市MSM人群对艾滋病防治相关的健康干预措施有较高的需求,加强反对歧视的宣传,多关心、多理解MSM人群,推广免费优质安全套等措施能有效满足MSM人群的健康和心理需求,对有效开展艾滋病防治工作具有重要意义。
文摘Polyreactive innate-type B cells account for many B cells expressing self-reactivity in the periphery. Improper regulation of these B cells may be an important factor that underlies autoimmune disease. Here we have explored the influence of self-reactive innate B cells in the development of collagen-induced arthritis （CIA）, a mouse model of rheumatoid arthritis. We show that splenic marginal zone （MZ）, but not B- 1 B cells exhibit spontaneous IgM reactivity to autologous collagen II in na＇=＇ve mice. Upon immunization with heterologous collagen II in complete Freund＇s adjuvant the collagen-reactive MZ B cells expanded rapidly, while the B-1 B cells showed a modest anti-collagen response. The MZ B cells were easily activated by toll-like receptor （TLR） 4 and 9-1igands in vitro, inducing proliferation and cytokine secretion, implying that dual engagement of the B-cell receptor and TLRs may promote the immune response to self-antigen. Furthermore, collagen-primed MZ B cells showed significant antigen-presenting capacity as reflected by cognate T-cell proliferation in vitroand induction of IgG anti-collagen antibodies in vivo. MZ B cells that were deficient in complement receptors I and 2 demonstrated increased proliferation and cytokine production, while Fcy receptor lib deficiency of the cells lead to increased cytokine production and antigen presentation. In conclusion, our data highlight self-reactive MZ B cells as initiators of the autoimmune response in CIA, where complement and Fc receptors are relevant in controlling the self-reactivity in the cells.
