期刊文献+
共找到266篇文章
< 1 2 14 >
每页显示 20 50 100
Z箍缩内爆的MARED程序1维模拟分析 被引量:12
1
作者 丁宁 邬吉明 +6 位作者 杨震华 符尚武 宁成 刘全 束小建 张扬 戴自换 《强激光与粒子束》 EI CAS CSCD 北大核心 2008年第2期212-218,共7页
研制可靠的数值模拟工具对Z箍缩内爆产生X光辐射过程进行理论研究、实验分析以及负载设计至关重要。介绍了2维三温辐射磁流体力学程序(MARED)的物理方案,给出了MARED程序的1维检验结果,验证表明MARED程序适用不同装置条件、不同负载参... 研制可靠的数值模拟工具对Z箍缩内爆产生X光辐射过程进行理论研究、实验分析以及负载设计至关重要。介绍了2维三温辐射磁流体力学程序(MARED)的物理方案,给出了MARED程序的1维检验结果,验证表明MARED程序适用不同装置条件、不同负载参数。结合丝阵Z箍缩实验的数值模拟和分析表明:相同负载质量条件下,钨丝阵内爆产生的X光辐射功率远大于铝丝阵产生的X光功率;相同负载电流条件下,负载质量越大,计算得到X光功率越低;X光功率随着负载电流增加而增加。 展开更多
关键词 Z箍缩 内爆等离子体 丝阵负载 mareD程序 数值模拟 X光辐射
在线阅读 下载PDF
固定化脂肪酶ANL-MARE催化酸解合成1-油酸-2-棕榈酸-3-亚油酸甘油三酯 被引量:1
2
作者 康梦 何家强 +7 位作者 冯孔龙 黄早成 李一峰 苗建银 符姜燕 朱泽榕 刘果 曹庸 《现代食品科技》 CAS 北大核心 2024年第2期109-119,共11页
1-油酸-2-棕榈酸-3-亚油酸甘油三酯(OPL)是人乳中主要的脂质组成,为满足婴幼儿配方食品母乳化需求,该试验探究了新型固定化脂肪酶ANL-MARE催化制备OPL的方法。试验成功制备和表征了固定化酶ANLMARE,并以ANL-MARE为生物催化剂,建立了一... 1-油酸-2-棕榈酸-3-亚油酸甘油三酯(OPL)是人乳中主要的脂质组成,为满足婴幼儿配方食品母乳化需求,该试验探究了新型固定化脂肪酶ANL-MARE催化制备OPL的方法。试验成功制备和表征了固定化酶ANLMARE,并以ANL-MARE为生物催化剂,建立了一种用三棕榈酸甘油三酯(PPP)、油酸(OA)和亚油酸(LA)高效酶催化制备富含OPL结构脂的方法。经单因素和响应面试验优化,获得OPL最优合成工艺为:PPP与总脂肪酸的摩尔比1:14.27,OA与LA摩尔比为1:0.76,脂肪酶添加量12.70%,反应温度50℃,反应4 h,此条件下产物中OPL相对含量为47.93%,2位棕榈酸(sn-2 PA)占总棕榈酸(PA)的质量分数(sn-2 PA相对含量)为71.69%。此外,固定化酶ANL-MARE与商业脂肪酶相比,表现出较好的催化合成OPL的活性。综上所述,固定化酶ANL-MARE具有催化制备OPL结构脂的重大潜力,为人乳脂替代脂的高效制备提供了新策略和理论基础。 展开更多
关键词 1-油酸-2-棕榈酸-3-亚油酸甘油三酯 酶促酸解法 固定化脂肪酶 ANL-mare 工艺优化
在线阅读 下载PDF
A comparative evaluation of methicillin-resistant staphylococci isolated from harness racing-horses,breeding mares and riding-horses in Italy 被引量:2
3
作者 Karina Mallardo Sandra Nizza +2 位作者 Filomena Fiorito Ugo Pagnini Luisa De Martino 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第3期169-173,共5页
Objective:To investigate the prevalence of methicillin-resistant staphylococci(MRS)which is a potencial risk factor of transmission between animals and humans in different types of horses(harness racing-horses,breedin... Objective:To investigate the prevalence of methicillin-resistant staphylococci(MRS)which is a potencial risk factor of transmission between animals and humans in different types of horses(harness racing-horses,breeding mares and riding-horses)and to compare the antimicrobial resistance of the isolates.Methods:A total of 191 healthy horses,housed at different locations of the Campania Region(Italy),were included in the study.Nasal swab samples were collected from each nostril of the horses.The mecA gene was detected by a nested PCR technique.Antibiotic susceptibility was tested for each isolate.Results:MRS was isolated from nasal samples of 68/191(35.6%;95%CI:28.9%-42.9%)healthy horses.All isolates were coagulase-negative with the exception of two coagulase-positive MRS strains,identified as Staphylococcus aureus and Staphylococcus pseudintermedius.2/83(2.4%;95%,CI:0.4%-9.2%).Interestingly,both coagulase-positive MRS isolates were from harness racing-horses.These horses also presented a significantly higher positivity for MRS(53.3%;95%CI:40.1%-66.1%)than the breeding mares and riding-horses groups.Antibiotic susceptibility testing showed difference between isolates due to different origins except for an almost common high resistance to aminopenicillins,such as ampicillin and amoxicillin.Conclusions:It can be concluded that harness racing-horses may act as a significant reservoir of MRS as compared to breeding mares and riding-horses. 展开更多
关键词 METHICILLIN-RESISTANT STAPHYLOCOCCI mareS HARNESS racing-horse Riding-horse Nasal swabs
在线阅读 下载PDF
Estimation of the elastic thickness over ancient Mare Moscoviense 被引量:2
4
作者 Zhen Zhong Jian-Guo Yan +2 位作者 Teng Zhang Zhi-Yong Xiao Jose Alexis Palmero Rodriguez 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第12期318-326,共9页
The Moscoviense basin is an atypical lunar impact basin with concentric rings of positive and negative gravity anomalies.This basin can provide insights into the inhomogeneous thermal activities across the farside of ... The Moscoviense basin is an atypical lunar impact basin with concentric rings of positive and negative gravity anomalies.This basin can provide insights into the inhomogeneous thermal activities across the farside of the Moon.Based on an updated spherical harmonic thin elastic-shell loading model,we used localized admittance analyses to estimate the elastic thickness as well as other associated selenophysical parameters for the Moscoviense basin.The high precision gravity and topography data employed in our estimation were collected by the Gravity Recovery and Interior Laboratory and the Lunar Orbiter Laser Altimeter missions.Our results indicate that the crust-mantle interface is mainly compensated by the prefilling depth rather than the observed surface topography.The results constrained within two standard deviations yielded a small load ratio(~0.168),a best-fit crustal thickness of 36.2 km,and an optimized crustal density of 3159.5 kg m-3.Such large density approaches the density of olivine-rich mantle materials,implying that the excavation of the Mare Moscoviense occurred during a basin-forming impact.The inversed elastic thickness at Mare Moscoviense was around 18 km,lower than the previous results(~60 km)found over Mare basins on the lunar nearside.These results indicate that extreme thermal activity existed during the Moscoviense basin-forming period such as reheating mechanisms from a double-impact process and mare volcanism. 展开更多
关键词 mare Moscoviense localized admittance thin elastic spherical shell elastic thickness
在线阅读 下载PDF
Endometritis associated with Enterococcus casseliflavus in a mare:A case report 被引量:1
5
作者 Francesca Paola Nocera Chiara Papulino +3 位作者 Chiara Del Prete Veronica Palumbo Maria Pia Pasolini Luisa De Martino 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2017年第8期760-762,共3页
Infectious endometritis is one of the main causes of subfertility/infertility in the mare. In this report, we present the first case of endometritis in mare associated with a strain of Enterococcus casseliflavus, an u... Infectious endometritis is one of the main causes of subfertility/infertility in the mare. In this report, we present the first case of endometritis in mare associated with a strain of Enterococcus casseliflavus, an unusual gram-positive bacterium which can also be a zoonotic agent. Furthermore, the isolated strain showed a worrying multidrug-resistant profile. The accurate finding of a successful antimicrobial treatment and consequently,the pregnancy diagnosis indicate the importance to isolate, identify and define the antibiotic resistance profile of bacteria associated with endometritis. 展开更多
关键词 ENDOMETRITIS Enterococcus casseliflavus mareS SUBFERTILITY
在线阅读 下载PDF
Two Lunar Mare Soil Simulants 被引量:1
6
作者 Yongquan LI Jianzhong LIU +3 位作者 Yongliao ZOU Ziyuan OUYANG Yongchun ZHENG Zongyu YUE 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第5期1016-1021,共6页
Two new lunar mare soil simulants,NAO-2 and NAO-3,have been created in National Astronomical Observatories(NAO),Chinese Academy of Sciences.These two simulants were produced from low-titanium basalt and high-titanium ... Two new lunar mare soil simulants,NAO-2 and NAO-3,have been created in National Astronomical Observatories(NAO),Chinese Academy of Sciences.These two simulants were produced from low-titanium basalt and high-titanium basalt respectively.The chemical composition,mineralogy, particle size distribution,density,angle of internal friction,and cohesion of both simulants have been analyzed,indicating that some characteristics of NAO-2 and NAO-3 are similar to those of Apollo 14 and Apollo 11 landing site soils.NAO-2 and NAO-3 will be of great benefit to the scientific and engineering research on lunar soil. 展开更多
关键词 lunar mare soil simulants
在线阅读 下载PDF
A novel strategy to extract lunar mare KREEP-rich metal resources using a silicon collector 被引量:1
7
作者 Chen Li Kuixian Wei +4 位作者 Yang Li Wenhui Ma Yun Lei Han Yu Jianzhong Liu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2023年第9期1429-1436,I0006,共9页
The lunar mare potassium(K)-,rare-earth elements(REEs)-and phosphorous(P)-rich(KREEP-rich) region is a unique late-stage product of magma crystallization,in which ilmenite and incompatible elements have high grades,th... The lunar mare potassium(K)-,rare-earth elements(REEs)-and phosphorous(P)-rich(KREEP-rich) region is a unique late-stage product of magma crystallization,in which ilmenite and incompatible elements have high grades,thus forming a giant natural reservoir.The extraction and purification of the high-value metal resources in the KREEP-rich region not only meet the construction needs of the lunar base but also solve the problem of resource scarcity on Earth.In this study,photovoltaic elemental silicon(Si) was used as a collector to extract ilmenite resources,REEs,and nuclear energy elements from basalt in the lunar mare KREEP-rich region at 1873 K.Based on experimentation,the metals titanium(Ti)and iron(Fe) in the lunar mare ilmenite are found to be enriched and solidified in the form of Si-based alloys.The contents of valuable incompatible elements in the KREEP-rich area are also found to be enriched and contained in the incompatible trace elements(ITEs) phase of the alloy.Among them,REEs(e.g.,cerium(Ce) and thulium(Tm)) and nuclear elements(e.g.,thorium(Th) and uranium(U)) are found to account for 82.61 wt% of the ITEs phase.This process provides a simple and feasible scheme for the insitu resource utilization(ISRU) of the lunar surface and is suitable for the extraction and enrichment of lunar metal resources. 展开更多
关键词 Lunar rare earth elements In situ resource Utilization Lunar mare ilmenite Si reduction
原文传递
Time of foaling in Arabian mares raised in Tiaret, Algeria
8
作者 Samia Meliani Bouabdellah Benallou +1 位作者 Miloud Halbouche Zohra Haddouche 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第7期587-588,共2页
Objective:To enhance effectiveness of reproduction management in Arabian mares,factorsinfluencing the time of foaling were investigated in this study.Methods:Data were collectedat the National Haras of Tiaret in Alger... Objective:To enhance effectiveness of reproduction management in Arabian mares,factorsinfluencing the time of foaling were investigated in this study.Methods:Data were collectedat the National Haras of Tiaret in Algeria from 2003 to 2010.The foaling time of 255 Arabian purebred mares,aged from 3 to 20 years were used for this study.Results:A total of 78.07%of foalinghappens between 7 pm and 6 am.Conclusions:The influence of the month of foaling and the sexof the foal,on the time of foaling was statically significant. 展开更多
关键词 Arabian mare TIME of FOALING REPRODUCTION FOAL heat
在线阅读 下载PDF
Endoscopic monitoring the estrous phase of Arabian mares with assaying its biopsy
9
作者 Mohamed Fathi Haithem AMFarghali +2 位作者 Nagla AAbdelkader Khattab MA El Karmoty AF 《Asian pacific Journal of Reproduction》 2017年第3期140-143,共4页
Objective:To evaluate the changes occur in the vagina, cervix and endometrium during the pre- ovulatory period in Arabian mares by using endoscope as a diagnostic tool as well as the availability of taking an endoscop... Objective:To evaluate the changes occur in the vagina, cervix and endometrium during the pre- ovulatory period in Arabian mares by using endoscope as a diagnostic tool as well as the availability of taking an endoscopic biopsy during this stage.Methods:Ten cyclic and healthy arabian mares were subjected to ultrasound scanning of their ovaries to estimate the diameter of the preovulatory follicles, collection of blood samples for estimating the hormonal levels (Estradiol-17β and progestrone) for confirming the estrous phase, endoscopic monitoring their vagina, cervix and endometrium, the availability of taking biopsical samples and histological examination of the obtained samples.Results:The obtained data revealed that, the mean diameter of the preovulatory follicles was (3.95±0.34) cm, the plasma estradiol and progestrone levels were (85.98±5.26) pg/mL and (0.73±0.23) ng/mL, respectively, endoscopic monitoring the vagina, cervix and endometrium revealed hyperemic vaginal mucous membrane, soft and opened cervical ostium with abundant estrous mucous and folding, hyperemic and edematous appearance of the endometrium, respectively and the histological features of the biopsical endometrial samples revealed that, The lamina propria-sub mucosa was packed with simple or branched tubular glands lined with simple columnar epithelium showing oval or rounded dark nuclei with different degrees of secretory activities of the glands.Conclusions: The endoscope proved to be a reliable tool for confirming the estrous phase in mares and monitoring the gross features of the vagina, the cervix and the endometrium, in addition to the availability of taking biopsical smears. 展开更多
关键词 Arabian mareS ENDOSCOPE ESTROUS
暂未订购
A heterogeneous lunar mantle revealed by young low-Ti mare basalt NWA 16460
10
作者 Weibiao Hsu Aoxin Mei +5 位作者 Yukang Liang Lei Jin Kai Zhao Lihui Chen Shaolin Li Chipui Tang 《Science Bulletin》 2025年第18期2963-2966,共4页
In the canonical view of lunar evolution,mare basalts are regarded as secondary partial melts of deep-seated lunar mantle formed as cumulates from a lunar magma ocean(LMO)during the early stage of lunar magmatism[1].M... In the canonical view of lunar evolution,mare basalts are regarded as secondary partial melts of deep-seated lunar mantle formed as cumulates from a lunar magma ocean(LMO)during the early stage of lunar magmatism[1].Mare basalts filled mainly near-side lunar basins and occupied approximately 17%of the lunar surface[2].Mare volcanism is a long-lived process(1.0 to 4.4 Ga)that primarily involved the emplacement of lunar basins during the era of large impact basin formation(3.5-3.8 Ga)[1].Some earlier pulses of volcanism(prior to 3.9 Ga)also existed on the moon but covered only a small area(2%)in the form of cryp-tomare basalts[3].Ancient lunar basalts are relatively enriched in Al,K,and rare earth elements(REEs).Representative rocks include high-Al,high-K,K-REE-P-rich rock(KREEP)and some cryp-tomare basalts[1],which were emplaced at the surface during a continuous episode contemporaneous with lunar crust formation[1].Younger patches of mare volcanism(as late as 1.0 Ga)have been recognized via remote sensing techniques[2].However,only the Chang’E 5(CE5)samples provided solid evidence for 2.0 Ga young volcanic activity[4,5].Mare volcanism on the lunar far side,while relatively sparse,follows a similar temporal distribution pat-tern[6]. 展开更多
关键词 lunar mantle emplacement lunar basins lunar magma ocean lmo large impact basin formation secondary partial melts lunar magmatism mare basalts mare basalts Lunar magma ocean
原文传递
Z箍缩内爆的MARED程序数值模拟分析 被引量:4
11
作者 丁宁 邬吉明 +6 位作者 戴自换 张扬 尹丽 姚彦忠 孙顺凯 宁成 束小建 《物理学报》 SCIE EI CAS CSCD 北大核心 2010年第12期8707-8716,共10页
MARED程序是模拟Z箍缩内爆过程的二维三温辐射磁流体力学程序,它适用于不同装置条件和不同负载参数.利用MARED程序对Z箍缩内爆进行模拟,结合丝阵Z箍缩实验分析表明:相同负载质量条件下,钨丝阵内爆产生的X射线辐射功率远大于铝丝阵产生的... MARED程序是模拟Z箍缩内爆过程的二维三温辐射磁流体力学程序,它适用于不同装置条件和不同负载参数.利用MARED程序对Z箍缩内爆进行模拟,结合丝阵Z箍缩实验分析表明:相同负载质量条件下,钨丝阵内爆产生的X射线辐射功率远大于铝丝阵产生的X射线功率;相同负载电流条件下,负载质量越大,计算得到的X射线功率越低;X射线功率随着负载电流增加而增加.MARED程序能够较好地反映Z箍缩内爆动力学过程,特别是不稳定性发展的二维图像,能够给出与不稳定性简化模型的理论分析及实验结果定性一致的演化规律.MARED程序模拟丝阵填充泡沫形成辐射场的初步计算得到了与Sandia实验室模拟Z装置上丝阵填充泡沫定性一致的结果. 展开更多
关键词 丝阵Z箍缩内爆等离子体 mareD程序 辐射磁流体力学数值模拟 X射线辐射
原文传递
SIMS Pb/Pb dating of Zr-rich minerals in lunar meteorites Miller Range 05035 and LaPaz Icefield 02224:Implications for the petrogenesis of mare basalt 被引量:2
12
作者 HSU WeiBiao 《Science China Earth Sciences》 SCIE EI CAS 2010年第3期327-334,共8页
Miller Range (MIL) 05035 and LaPaz Icefield (LAP) 02224 are unbrecciated lunar basalt meteorites. In this report, we studied their petrography and mineralogy and made in situ uranogenic Pb/Pb dating of Zr-rich mineral... Miller Range (MIL) 05035 and LaPaz Icefield (LAP) 02224 are unbrecciated lunar basalt meteorites. In this report, we studied their petrography and mineralogy and made in situ uranogenic Pb/Pb dating of Zr-rich minerals. Petrography and mineralogy of these two lunar meteorites are consistent with previous investigations. The zirconolite Pb/Pb age of MIL 05035 is 3851±8 Ma (2σ), in excellent agreement with previous reports. This age suggests that MIL 05035 could be paired with Asuka 881757, a low-Ti mare basalt meteorite. The magmatic event related to MIL 05035 was probably due to the late heavy impact bom- bardment on the moon around 3.9 Ga. One baddeleyite grain in LAP 02224 shows a large variation of Pb/Pb age, from 3109±29 to 3547±21 Ma (2σ), much older than the whole-rock age of the same meteorite (~3.02±0.03 Ga). The other baddeleyite grain in LAP 02224 has an age of 3005±17 Ma (2σ). The result indicates that the minimum crystallization age of LAP 02224 is ~3.55 Ga and the younger ages could reflect late thermal disturbance on U-Pb system. 展开更多
关键词 Pb/Pb DATING SIMS ZIRCONOLITE and BADDELEYITE lunar METEORITE low-Ti mare basalt
原文传递
1∶250万月球酒海幅(LQ-20)地质图编研
13
作者 刘敬稳 刘建忠 +4 位作者 朱凯 张敬宜 张珂 吴聪哲 雷丹泓 《遥感学报》 北大核心 2025年第2期553-565,共13页
在嫦娥探月数据及其他月球地质资料的基础上,中国科学院地球化学研究所主导的团队编制了比例尺为1∶250万的全月地质图、月球分幅地质图、月球构造纲要图、月球岩石分布图以及30分幅地质图,其中就包括LQ-20酒海幅。LQ-20图幅以其独特的... 在嫦娥探月数据及其他月球地质资料的基础上,中国科学院地球化学研究所主导的团队编制了比例尺为1∶250万的全月地质图、月球分幅地质图、月球构造纲要图、月球岩石分布图以及30分幅地质图,其中就包括LQ-20酒海幅。LQ-20图幅以其独特的酒海纪与艾肯纪交界的标志事件——酒海盆地撞击事件而引人注目。本文详细介绍了月球地质图的编研的发展历史、LQ-20分幅图的图幅表达的内容,并阐述了该图幅表达的岩石类型、撞击盆地和撞击坑物质、构造形迹特征等:图幅中表达了12类岩石类型、8个盆地的地质信息、260个撞击坑的坑物质、16类构造形迹特征,涉及了整个三宙六纪的地质信息。最后讨论了该月球图幅区域内从岩浆洋纪到哥白尼纪的整体区域地质演化历史,并通过对比分析LQ20的制图结果提出中国1∶250万月球地质图与美国月球地质图在表达地质信息上的本质区别在于其对月球地质过程整体的地质体系的完整建立与系统表达,每处地质信息都明确表达其地质作用来源,每个区域都有层次分明的按形成顺序排列的地质过程,这充分论证了中国1∶250万月球地质图能够为中国乃至全球月球就位探测、科学研究等提供了一份详尽的月球地质背景资料。 展开更多
关键词 遥感 月球地质图 LQ-20 酒海盆地 遥感解译 月球地质演化历史
原文传递
月海玄武岩硫化物特征及其岩浆硫化物饱和状态
14
作者 曹勇华 胡靖琳 +1 位作者 黄钰庭 许晶瑶 《中南大学学报(自然科学版)》 北大核心 2025年第11期4512-4521,共10页
本文系统收集并分析阿波罗计划、嫦娥工程返回样品及月球陨石资料,结合alphaMELTS热力学模拟,揭示月海玄武岩中硫化物的类型、分布特征与成因机制,评估月球内部的硫饱和状态与金属硫化物的成矿潜力。研究结果表明:月海玄武岩中的硫化物... 本文系统收集并分析阿波罗计划、嫦娥工程返回样品及月球陨石资料,结合alphaMELTS热力学模拟,揭示月海玄武岩中硫化物的类型、分布特征与成因机制,评估月球内部的硫饱和状态与金属硫化物的成矿潜力。研究结果表明:月海玄武岩中的硫化物类型以陨硫铁(FeS)为主,伴生少量的黄铜矿(CuFeS_(2))、方黄铜矿(CuFe_(2)S_(3))和镍黄铁矿((Fe,Ni)_(9)S_(8)),其中陨硫铁主要以填隙物的形式产于硅酸盐矿物之间;相较于月海低钛玄武岩,高钛玄武岩具有更高的全岩硫质量分数和δ34S值;两类玄武岩的全岩硫质量分数均与全岩MgO质量分数呈显著负相关,而δ34S值变化范围窄且与硫质量分数无明显相关性;高钛玄武岩与低钛玄武岩的月幔源区硫质量分数分别为16~24μg/g和17~38μg/g,远低于月幔硫饱和质量分数。岩浆去气作用对硫质量分数和硫同位素分馏的影响有限,且月海玄武质岩浆在演化过程中始终未达到硫化物饱和状态。因此,月球内部缺乏形成岩浆硫化物矿床的条件,月海玄武岩中的硫化物主要在岩浆演化晚期由残余熔体结晶而成。 展开更多
关键词 月海玄武岩 硫化物 岩浆硫化物饱和 陨硫铁
在线阅读 下载PDF
一篇典型的月球版地幔地球化学研究论文——学术、学科意义解读与嫦娥系列成果产出背景解析
15
作者 周新华 《矿物岩石地球化学通报》 北大核心 2025年第4期786-789,共4页
本文对嫦娥6号阿波罗盆地玄武岩的地幔地球化学研究初步成果进行了述评,肯定了应用样品Sr,Nd同位素特征反演其源区为极端亏损地幔属性发现的重要学术意义,并将其与地球亏损地幔物质直接进行了对比。这一成果对月球早期演化史、月球的内... 本文对嫦娥6号阿波罗盆地玄武岩的地幔地球化学研究初步成果进行了述评,肯定了应用样品Sr,Nd同位素特征反演其源区为极端亏损地幔属性发现的重要学术意义,并将其与地球亏损地幔物质直接进行了对比。这一成果对月球早期演化史、月球的内部组成,特别是月幔的化学结构以及月球正面与背面重大差异机制的研究将产生重大影响。作者进而指出嫦娥5号和嫦娥6号成果应是地幔地球化学应用于月球科学成功的明证与开端,更是化学地球动力学应用于行星科学成功的明证与开端。本文强调了嫦娥工程回收样品研究系列成果获取的五方面背景:即深厚的学术积累、坚实的同位素年代学与同位素地球化学的学科基础、老中青三结合的人才梯队、学术引领。技术先行的实验体系和集中力量办大事体制化组织优势的集成。 展开更多
关键词 嫦娥6号 月海玄武岩 Sr、Nd同位素 极端亏损地幔 地幔地球化学
原文传递
长效黄体酮在同期发情-定时输精技术中的应用
16
作者 杨阳 王煜舒 +3 位作者 万姣 茅渊 窦立静 欧四海 《养殖与饲料》 2025年第4期20-23,共4页
[目的]研究长效黄体酮优化同期发情-定时输精程序技术在规模化奶牛场中的优化应用方案,提高母牛产后配种妊娠率。[方法]选取荷斯坦奶牛与荷弗杂交牛混养试验场,设置6个试验组,产后45 d同期发情-定时输精的荷弗牛(A组)和荷斯坦奶牛(B组)... [目的]研究长效黄体酮优化同期发情-定时输精程序技术在规模化奶牛场中的优化应用方案,提高母牛产后配种妊娠率。[方法]选取荷斯坦奶牛与荷弗杂交牛混养试验场,设置6个试验组,产后45 d同期发情-定时输精的荷弗牛(A组)和荷斯坦奶牛(B组)在0-7-9同期发情-定时输精程序技术的基础上,采用第0天增加长效黄体酮、第7天增加孕马血清处理方法优化程序,比较同一输精程序下不同品种的妊娠率;产后自然发情配种的荷弗牛(C组)和荷斯坦奶牛(D组),比较自然发情条件下不同品种的妊娠率;试验场荷斯坦奶牛(E组)用长效黄体酮优化同期发情-定时输精程序配种,对照场荷斯坦奶牛(F组)用基础程序配种,比较同品种不同处理方法的妊娠率。[结果]试验A组、B组长效黄体酮优化同期发情-定时输精程序妊娠率荷弗杂交牛比荷斯坦奶牛提高2.17百分点;C组、D组产后母牛自然发情受胎率荷弗杂交牛比荷斯坦奶牛提高17.31百分点;E组、F组荷斯坦牛受胎率长效黄体酮优化同期发情-定时输精程序比基础程序提高17.35百分点。[结论]在同期发情-定时输精程序技术基础上应用长效黄体酮,能有效提高产后奶牛的受胎率。 展开更多
关键词 长效黄体酮 孕马血清 同期发情-定时输精程序技术 妊娠率 产后奶牛
在线阅读 下载PDF
Seasonal influence on miRNA expression dynamics of extracellular vesicles in equine follicular fluid
17
作者 Jean M.Feugang Ahmed Gad +7 位作者 Nico G.Menjivar Ghassan M.Ishak Samuel Gebremedhn Melba O.Gastal Notsile H.Dlamini Radek Prochazka Eduardo L.Gastal Dawit Tesfaye 《Journal of Animal Science and Biotechnology》 2025年第1期136-152,共17页
Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellu... Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellular vesicles(EVs)containing vital regulatory molecules,such as microRNAs(miRNAs).These miRNAs are pivotal in facilitating commu-nication within the follicles through diverse signaling and information transfer forms.EV-coupled miRNA signaling is implicated to be associated with ovarian function,follicle and oocyte growth and response to various environmen-tal insults.Herein,we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.Results Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the ano-vulatory(spring:non-breeding)and ovulatory(spring,summer,and fall:breeding)seasons and subsequent EV isola-tion and miRNA profiling identified significant variation in EV-miRNA cargo content.We identified 97 miRNAs with dif-ferential expression among the groups and specific clusters of miRNAs involved in the spring transition(miR-149,-200b,-206,-221,-328,and-615)and peak breeding period(including miR-143,-192,-451,-302b,-100,and let-7c).Bioinformatic analyses showed enrichments in various biological functions,e.g.,transcription factor activity,transcrip-tion and transcription regulation,nucleic acid binding,sequence-specific DNA binding,p53 signaling,and post-trans-lational modifications.Cluster analyses revealed distinct sets of significantly up-and down-regulated miRNAs associ-ated with spring anovulatory(Cluster 1)and summer ovulation–the peak breeding season(Clusters 4 and 6).Conclusions The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons,and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation. 展开更多
关键词 Extracellular vesicle Follicle growth Follicular fluid HORSE mare OVULATION Pre-ovulation Seasonal breeding
在线阅读 下载PDF
鲜马奶细菌多样性分析及乳酸菌的益生研究 被引量:1
18
作者 张华丽 王悦 +2 位作者 王伟亮 胡圣伟 倪伟 《内蒙古农业大学学报(自然科学版)》 北大核心 2025年第3期37-46,共10页
鲜马奶中蕴含着丰富的乳酸菌资源,本文采用Illumina MiSeq高通量测序法解析鲜马奶细菌的多样性,同时基于传统纯培养方法和16S rRNA基因序列测序分析法分离鉴定乳酸菌,并且对获得的乳酸菌进行益生特性研究。结果表明,厚壁菌门(Firmicutes... 鲜马奶中蕴含着丰富的乳酸菌资源,本文采用Illumina MiSeq高通量测序法解析鲜马奶细菌的多样性,同时基于传统纯培养方法和16S rRNA基因序列测序分析法分离鉴定乳酸菌,并且对获得的乳酸菌进行益生特性研究。结果表明,厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)是鲜马奶的优势群门,平均相对丰度分别为93.67%和4.86%。乳杆菌属(Lactobacillus)和乳球菌属(Lactococcus)是优势细菌属,占所有菌群的比例分别为82.47%和7.17%。从鲜马奶中共分离32株乳酸菌,其中20株植物乳植杆菌(Lactiplantibacillus plantarum)、6株面包伴生乳杆菌(Companilactobacillus crustorum)、1株副干酪乳酪杆菌(Lacticaseibacillus paracasei)、5株粪肠球菌(Enterococcus faecalis)。通过耐酸耐胆盐测定,发现菌株ALT6、ALT10、ALT53、ALT99在pH 2.0酸性条件和0.5%胆盐浓度下耐受能力较强。耐模拟胃肠液测定中这4株菌株在模拟胃液3 h的存活率分别为81%、86.72%、91.87%、74.43%,模拟肠液6 h存活率分别为60.39%、50.5%、89.68%、51.85%。在自聚集、体外抑菌试验中植物乳植杆菌ALT53的自聚集能力最高达到89.24%,对大肠埃希氏菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、沙门氏菌(Salmonella)都具有良好抑菌作用。综上所述,分离到的一株植物乳植杆菌ALT53具有潜在的优良益生特性。 展开更多
关键词 鲜马奶 细菌多样性 乳酸菌 分离鉴定 益生特性
原文传递
分离、鉴定和筛选具有益生特性和降胆固醇能力的发酵马乳源益生菌 被引量:1
19
作者 库尔旦·胡达依别尔根 刘学莲 +3 位作者 卡吾萨尔·恰依马尔旦 何瑶 巴合班·叶尔江 新华·那比 《食品与发酵工业》 北大核心 2025年第11期171-178,共8页
为筛选具有益生特性和降胆固醇能力的发酵马乳源发酵菌。该研究从传统发酵马乳中分离纯化了4株乳酸菌,并对其形态学和生理生化特征,生长曲线、胆盐耐受能力、人工胃液耐受能力和抗生素敏感性等特性进行了评价。进而通过胆盐水解酶活性... 为筛选具有益生特性和降胆固醇能力的发酵马乳源发酵菌。该研究从传统发酵马乳中分离纯化了4株乳酸菌,并对其形态学和生理生化特征,生长曲线、胆盐耐受能力、人工胃液耐受能力和抗生素敏感性等特性进行了评价。进而通过胆盐水解酶活性定性检测法和胆固醇氧化酶法评估了发酵菌在体外的胆固醇清除能力,最后对筛选的菌株进行了16S rRNA鉴定。结果表明,分离的4株菌对高胆盐(3.0 g/L)和人工胃液(pH 2.0)具有较好的耐受性并且对所选8种抗生素多数表现敏感;在4株菌的滤纸片周围观察到了明显的白色沉淀圈,表明其均具有胆盐水解酶活性;单一菌及复合菌对培养基中胆固醇的清除率为(76.46±1.26)%~(87.96±0.43)%,且复合菌胆固醇清除能力高于其单一菌株,最后经16S rRNA基因测序鉴定为植物乳植杆菌(Lactiplantibacillus plantarum)。可见分离的4株菌具有益生的基本特性和较高的安全性,同时在体外具有较好的降胆固醇能力,可进一步探究其在体内的机制。 展开更多
关键词 传统发酵马乳 益生特性 抗生素敏感性 胆盐水解酶 降胆固醇作用
在线阅读 下载PDF
马乳清蛋白ACE、DPP-Ⅳ、AG抑制肽的分离及鉴定
20
作者 娄肖肖 赵艳坤 +3 位作者 郑楠 陈贺 马梅 邵伟 《中国畜牧兽医》 北大核心 2025年第12期5651-5660,共10页
【目的】从马乳清蛋白水解产物中分离鉴定对血管紧张素转换酶(ACE)、二肽基肽酶-Ⅳ(DPP-Ⅳ)和α-葡萄糖苷酶(AG)具有多重抑制活性的多肽。【方法】自新疆乌鲁木齐南山牧场采集15份生马乳样品,以马乳清蛋白为底物,分别用单酶(胰蛋白酶、... 【目的】从马乳清蛋白水解产物中分离鉴定对血管紧张素转换酶(ACE)、二肽基肽酶-Ⅳ(DPP-Ⅳ)和α-葡萄糖苷酶(AG)具有多重抑制活性的多肽。【方法】自新疆乌鲁木齐南山牧场采集15份生马乳样品,以马乳清蛋白为底物,分别用单酶(胰蛋白酶、中性蛋白酶和碱性蛋白酶)、双酶(胰蛋白酶+中性蛋白酶)和三酶(胰蛋白酶+中性蛋白酶+碱性蛋白酶)进行水解,通过超滤法对水解产物进行分离;通过测定ACE抑制活性评价各级分离产物的降血压活性,通过测定AG抑制活性和DPP-Ⅳ抑制活性评价各级分离产物的降血糖活性;通过液质联用(LC-MS/MS)的方法鉴定多肽的氨基酸组成,根据鉴定结果化学合成活性较好的多肽,并体外测定其抑制活性。【结果】与单酶、双酶水解产物相比,三酶水解产物的水解度(74.33%)、ACE抑制活性(22.81%)、DPP-Ⅳ抑制活性(23.46%)及AG抑制活性(20.77%)均显著提高(P<0.05)。从活性最优的三酶水解产物中分离鉴定出具有多重抑制活性的新型多肽系列(HSVAMAASDISLLDSESAPLR、TQMVDEEIMEK、VQIVPDLTR、RALQPLPGRVQIVPDLTR、TELTEEEKNYLK、LRPTPEDNLEIILR);体外化学合成这几种多肽,并测定其活性,结果显示,TQMVDEEIMEK对ACE抑制率达99.89%,VQIVPDLTR对DPP-Ⅳ抑制率达90.85%,TELTEEEKNYLK对AG抑制率达97.87%。【结论】本研究从马乳清蛋白水解产物中成功分离鉴定出6种具有ACE、DPP-Ⅳ、AG多重抑制活性的新型多肽,为马乳功能性产品的开发提供了理论依据。 展开更多
关键词 马乳清蛋白 生物活性肽 抑制活性
在线阅读 下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部