LAMOST （Large sky Area Multi-Object fiber Spectroscopic Telescope） is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences （NAOC）. After two ...LAMOST （Large sky Area Multi-Object fiber Spectroscopic Telescope） is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences （NAOC）. After two years of commis- sioning beginning in 2009, the telescope, instruments, software systems and opera- tions are nearly ready to begin the main science survey. Through a spectral survey of millions of objects in much of the northern sky, LAMOST will enable research in a number of contemporary cutting edge topics in astrophysics, such as discovery of the first generation stars in the Galaxy, pinning down the formation and evolution history of galaxies - especially the Milky Way and its central massive black hole, and look- ing for signatures of the distribution of dark matter and possible sub-structures in the Milky Way halo. To maximize the scientific potential of the facility, wide national par- ticipation and international collaboration have been emphasized. The survey has two major components： the LAMOST ExtraGAlactic Survey （LEGAS） and the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE）. Until LAMOST reaches its full capability, the LEGUE portion of the survey will use the available ob- serving time, starting in 2012. An overview of the LAMOST project and the survey that will be carried out in the next five to six years is presented in this paper. The sci- ence plan for the whole LEGUE survey, instrumental specifications, site conditions, and the descriptions of the current on-going pilot survey, including its footprints and target selection algorithm, will be presented as separate papers in this volume.展开更多
OBJECTIVE:To assess the efficacy and safety of heat-sensitive moxibustion in the treatment of lumbar disc herniation(LDH).METHODS:Randomized controlled trials(RCTs) involving heat-sensitive moxibustion in the treatmen...OBJECTIVE:To assess the efficacy and safety of heat-sensitive moxibustion in the treatment of lumbar disc herniation(LDH).METHODS:Randomized controlled trials(RCTs) involving heat-sensitive moxibustion in the treatment of LDH were retrieved from the Chinese Biological Medical Literature database(1978-20011),Weipu database(1989-2011),Wanfang digital journal(1998-2011),China National Knowledge Internet(1979-2011),PubMed(1966-2011),EMBASE(1980-2011),and Cochrane Library(Issue 1,2011).Hand-search of the relevant journals from the Library of Jiangxi University of Traditional Chinese Medicine was also adopted for the collection of data.Data were extracted and evaluated by two reviewers independently with a specially designed extraction form.The Cochrane Collaboration's RevMan 5.0.20 software was used for data analyses.RESULTS:A total of 6 trials involving 580 patients were included.Meta-analysis showed that the total effectiveness rate in the heat-sensitive moxibustion group was significantly different when compared with conventional moxibustion [RR=1.19,95% CI [1.06,1.33)] and diclofenac sodium [RR=1.47,95% CI [1.17,1.85)],but similar to that of acupuncture.The cure rate in the heat-sensitive moxibustion group was significantly different when compared with conventional moxibustion [RR=1.58,95% CI(1.04,2.40)] and diclofenac sodium [RR=1.91,95% CI(1.01,3.60)],but similar with that of acupuncture.In terms of the Japanese Orthopaedic Association scores,significant differences were noted in subjective indices,objective indices,and daily life subscales.Two trials reported that there were no adverse events over the duration of treatment.CONCLUSION:Compared with conventional moxibustion,acupuncture,and diclofenac sodium,heat-sensitive moxibustion in the treatment of LDH is superior in efficacy.Further large-scale trials are required to define the role of heat-sensitive moxibustion in the treatment of this disease.展开更多
Transforaminal Percutaneous Endoscopic Discectomy(TPED) is a minimally invasive technique mainly used for the treatment of lumbar disc herniation from a lateral approach. Performed under local anesthesia, TPED has bee...Transforaminal Percutaneous Endoscopic Discectomy(TPED) is a minimally invasive technique mainly used for the treatment of lumbar disc herniation from a lateral approach. Performed under local anesthesia, TPED has been proven to be a safe and effective technique which has been also associated with shorter rehabilitation period, reduced blood loss, trauma, and scar tissue compared to conventional procedures. However, the procedure should be performed by a spine surgeon experienced in the specific technique and capable of recognizing or avoiding various challenging conditions. In this review, pitfalls that a novice surgeon has to be mindful of, are reported and analyzed.展开更多
To assess the seasonal and spatial variations and long-term trends in water optical properties in Lake Fuxian, investigations based on field work in four seasons and a long-term analysis of data from 1980 to 2014 were...To assess the seasonal and spatial variations and long-term trends in water optical properties in Lake Fuxian, investigations based on field work in four seasons and a long-term analysis of data from 1980 to 2014 were conducted. The results show that there was no significant variation in the euphotic depth（Z（eu）） across the four seasons, and no significant correlations between Z（eu） and potential influencing factors in seasons other than summer, suggesting that the water itself may be a major factor regulating the Z（eu）in general. Nevertheless, significant differences in Z（eu） between the north region（NR） and the south region（SR） were observed in all seasonal tests except spring. This finding relates to a higher abundance of chromophoric dissolved organic matter（CDOM） in the NR due to runoff, especially in the rainy seasons（summer and autumn）.CDOM and its terrigenous component had an important impact on Z（eu）in summer, with the highest precipitation, and impacts from suspended solids and non-algal particles were also found in the NR in summer. The Secchi disk depth in the lake decreased clearly over the years,with significantly negative correlations with the increasing permanganate index and air temperature, implying that organic contaminants（CDOM and/or phytoplankton） are important regulators of water transparency. We estimate that the combined effects of climate warming and changes in land use and land cover are also indirect regulating factors. These findings should be considered in the protection of Lake Fuxian, owing to the importance of light penetration in aquatic ecosystems.展开更多
A computer code, ELANEX, including several Homogenous-Equilibrium-Model （HEM） type cavitation models, were developed, to numerically simulate natural cavitation phenomena. The effectiveness of the code was checked b...A computer code, ELANEX, including several Homogenous-Equilibrium-Model （HEM） type cavitation models, were developed, to numerically simulate natural cavitation phenomena. The effectiveness of the code was checked by cavitation flows around the disk and cylinder body for a wide range of different cavitation numbers. Cavity profiles were compared with the analytic solution of disk and empirical formulae fitted from the experiment data, and contrast between different cavitation models were fulfilled as well. The cavity length and maximal cavity diameter were found to agree well with the analytic solutions, and detailed cavity profiles were in accordance with the experimental formula. Comparison with the hemisphere headed cylinder body presented a good agreement of the pressure coefficient with the experiment data. Reasonable drag-force coefficient variation and drag-force reduction effect were obtained.展开更多
We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope （GSJT, formerly calledthe Large sky Area Multi-Object fiber Spectroscopic Telesc...We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope （GSJT, formerly calledthe Large sky Area Multi-Object fiber Spectroscopic Telescope -- LAMOST）. The survey will obtain spectra for 2.5 million stars brighter than r 〈 19 during dark/grey time, and 5 million stars brighter than r 〈 17 or J 〈 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope＇s design constrains the optimal declination range for observations to 10~ 〈 di 〈 50~, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies： disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey will be completed in summer 2012, after a review of the results of the pilot survey.展开更多
Objective： To observe the clinical efficacy of electroacupuncture and waist-building exercise in treating lumbar disk herniation. Methods： A multi-center, randomized controlled trial was adopted. Three hundred cases...Objective： To observe the clinical efficacy of electroacupuncture and waist-building exercise in treating lumbar disk herniation. Methods： A multi-center, randomized controlled trial was adopted. Three hundred cases of lumbar disk herniations were divided into two groups, an observation group in which 149 cases were treated by electroacupuncture and waist-building exercise, and a control group in which 151 cases were treated by electroacupuncture alone. The clinical efficacy and long-term relapse rate were observed and compared between the two groups. Results： Among 149 cases in the observation group, 80 cases were cured, 57 cases improved, 12 cases failed and 4 cases relapsed; the cure rate was 53.7%, the total effective rate was 91.9% and the relapse rate was 5.0%. Among 151 cases in the control group, 74 cases were cured, 51 cases improved, 26 cases failed and 12 cases relapsed; the cure rate was 49.0%, the total effective rate was 82.8% and the relapse rate was 16.2%. There were significant differences in the cure rate and the total effective rate between the two groups （P〈0.05）. Conclusion： Combined electroacupuncture and waist-building exercise had better effects than electroacupuncture in treating lumbar disk herniation.展开更多
湖水透明度能直观反映湖水清澈和混浊程度,是水体能见程度的一个量度,同时也是评价湖泊富营养化,衡量水质优劣的一个重要指标。传统地表水透明度观测主要采用塞克盘(Secchi Disk)法,这种方法不仅费时费力,而且只具有局部的代表意义。遥...湖水透明度能直观反映湖水清澈和混浊程度,是水体能见程度的一个量度,同时也是评价湖泊富营养化,衡量水质优劣的一个重要指标。传统地表水透明度观测主要采用塞克盘(Secchi Disk)法,这种方法不仅费时费力,而且只具有局部的代表意义。遥感技术具有快速、大面积和周期性的特点,可以有效地解决这种局限性。该文通过查干湖高光谱数据,建立透明度(Secchi Disk Depth)单波段和比值高光谱估测遥感模型,并进行验证。结果表明:利用高光谱遥感监测模型对查干湖透明度进行估算和监测,能够获取较为准确的评价结果,相对于传统监测方法具有省时省力的特点。通过对单波段估测模型和比值估测模型进行比较发现,单波段模型估测结果好于比值模型,而对数比值模型又强于单纯的比值模型。查干湖透明度高光谱定量估测模型的建立,有利于今后利用遥感影像,对查干湖水体透明度进行全面估测,对于研究和监测查干湖水体水质状况有重要意义。展开更多
椎间盘退行性变（Intervertebral disk degeneration，IVDD）是一系列脊柱退行性疾病的前提和基础病理过程。这一过程不仅表现为细胞种类和形态学上的变化，更伴随有椎间盘的组织学与生化性质的改变。目前引起椎间盘退变的确切机制尚无...椎间盘退行性变（Intervertebral disk degeneration，IVDD）是一系列脊柱退行性疾病的前提和基础病理过程。这一过程不仅表现为细胞种类和形态学上的变化，更伴随有椎间盘的组织学与生化性质的改变。目前引起椎间盘退变的确切机制尚无定论。但研究发现椎间盘中的细胞因子（Cytokines，CK）在椎间盘退行性变的病理过程中可能发挥着重要的调控作用。现就细胞因子在椎间盘退变中的作用研究状况综述如下：展开更多
对美国3M公司的锶特效固相萃取片(EmporeTMStrontium Rad Disk)分离水溶液中锶离子的性能进行了系统研究,包括酸度、流速、样品体积对吸附百分比的影响,吸附容量的测定,137 Cs和99 Tc在萃取片上的吸附情况等,并对萃取片上90Sr的解吸及片...对美国3M公司的锶特效固相萃取片(EmporeTMStrontium Rad Disk)分离水溶液中锶离子的性能进行了系统研究,包括酸度、流速、样品体积对吸附百分比的影响,吸附容量的测定,137 Cs和99 Tc在萃取片上的吸附情况等,并对萃取片上90Sr的解吸及片上90Sr的放射性测量进行了研究。在此基础上,给出了萃取片法分析环境水中90Sr的推荐程序。样品体积为1L,液闪测量时间为1h时,分析程序的最小可探测活度浓度为0.033Bq/L。最后应用一些实际环境水样对该程序进行了检验。展开更多
The success of a tunnel-boring machine （TBM） in a given project depends on the functionality of all components of the system, from the cutters to the backup system, and on the entire rolling stock. However, no part ...The success of a tunnel-boring machine （TBM） in a given project depends on the functionality of all components of the system, from the cutters to the backup system, and on the entire rolling stock. However, no part of the machine plays a more crucial role in the efficient operation of the machine than its cutterhead. The design of the cutterhead impacts the efficiency of cutting, the balance of the head, the life of the cutters, the maintenance of the main bearing/gearbox, and the effectiveness of the mucking along with its effects on the wear of the face and gage cutters/muck buckets. Overall, cutterhead design heavily impacts the rate of penetration （ROP）, rate of machine utilization （U）, and daffy advance rate （AR）. Although there has been some discussion in commonly available publications regarding disk cutters, cutting forces, and some design features of the head, there is limited literature on this subject because the design of cutter- heads is mainly handled by machine manufacturers. Most of the design process involves proprietary algorithms by the manufacturers, and despite recent attention on the subject, the design of rock TBMs has been somewhat of a mystery to most end-users. This paper is an attempt to demystify the basic concepts in design. Although it may not be sufficient for a full-fledged design by the readers, this paper allows engineers and contractors to understand the thought process in the design steps, what to Look for in a proper design, and the implications of the head design on machine operation and life cycle.展开更多
Objective： To construct the recombinant baculovirus Ac-cytomegalovirus （CMV）-hSox9 for gene therapy of intervertebral disc degeneration. Methods： Bac-to-Bac system was used for the construction of baculovirus Ac-C...Objective： To construct the recombinant baculovirus Ac-cytomegalovirus （CMV）-hSox9 for gene therapy of intervertebral disc degeneration. Methods： Bac-to-Bac system was used for the construction of baculovirus Ac-CMV-hSox9. The cDNA of hSox9 was first cloned into a plasmid vector under the control of CMV promotor to generate the donor plasmid pFastBacDul-green fluorescene protein （ GFP ）-CMV （pgGC）-hSox9. The resultant plasmid was transformed into DH10Bac cells and then the transformation mixture was spread on Luria-Bertani （LB） agarose culture medium containing isopropyl-β-D-thiogalactoside （IPTG）, X-gal, gentamicin, kanamycin and tetracycline. The white colonies were selected and cultured for amplification, and the hSox9 Bacmid DNA was extracted. After verification, recombinant baculovirns Ac-CMV-hSox9 was obtained through transfecting Sf 21 cells. The expression of hSox9 gene in the intervertebral disc cells in rabbits was determined by Western blotting and immunohistochemical staining. Results： Polymerase chain reaction （ PCR ） confirmed the presence of hSox9 gene in the recombinant baculovirus and the Sf 21 cells transfected by the baculovirus showed the expression of fluorescence protein. Western blotting and indicated that exogenous hSox9 disc cells. staining analysis Conclusions： The successful construction of the recombinant baculovirus Ac-CMV-hSox9 and the confirmation of the target gene expression provides a novel expression vector system for basic research and clinical treatment of intervertebral degenerative disc disease.展开更多
基金the National Natural Science Foundation of China (GrantNos. 10573022, 10973015 and 11061120454)that Heidi J. Newberg from RPI and her team PLUS (Participating LAMOST, US) have made substantial contributions in designing the survey under the support of the US National Science Foundation through grant AST-09-37523
文摘LAMOST （Large sky Area Multi-Object fiber Spectroscopic Telescope） is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences （NAOC）. After two years of commis- sioning beginning in 2009, the telescope, instruments, software systems and opera- tions are nearly ready to begin the main science survey. Through a spectral survey of millions of objects in much of the northern sky, LAMOST will enable research in a number of contemporary cutting edge topics in astrophysics, such as discovery of the first generation stars in the Galaxy, pinning down the formation and evolution history of galaxies - especially the Milky Way and its central massive black hole, and look- ing for signatures of the distribution of dark matter and possible sub-structures in the Milky Way halo. To maximize the scientific potential of the facility, wide national par- ticipation and international collaboration have been emphasized. The survey has two major components： the LAMOST ExtraGAlactic Survey （LEGAS） and the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE）. Until LAMOST reaches its full capability, the LEGUE portion of the survey will use the available ob- serving time, starting in 2012. An overview of the LAMOST project and the survey that will be carried out in the next five to six years is presented in this paper. The sci- ence plan for the whole LEGUE survey, instrumental specifications, site conditions, and the descriptions of the current on-going pilot survey, including its footprints and target selection algorithm, will be presented as separate papers in this volume.
基金Supported by the National "11th 5-year Plan" (2006BAI12B04-2)National Plan on Developing Key Basic Researches("973" Plan)(2009CB522902)+1 种基金State Natural Science Fund(30760320)a project of Key Sci-tech Support Plan in Jiangxi Province
文摘OBJECTIVE:To assess the efficacy and safety of heat-sensitive moxibustion in the treatment of lumbar disc herniation(LDH).METHODS:Randomized controlled trials(RCTs) involving heat-sensitive moxibustion in the treatment of LDH were retrieved from the Chinese Biological Medical Literature database(1978-20011),Weipu database(1989-2011),Wanfang digital journal(1998-2011),China National Knowledge Internet(1979-2011),PubMed(1966-2011),EMBASE(1980-2011),and Cochrane Library(Issue 1,2011).Hand-search of the relevant journals from the Library of Jiangxi University of Traditional Chinese Medicine was also adopted for the collection of data.Data were extracted and evaluated by two reviewers independently with a specially designed extraction form.The Cochrane Collaboration's RevMan 5.0.20 software was used for data analyses.RESULTS:A total of 6 trials involving 580 patients were included.Meta-analysis showed that the total effectiveness rate in the heat-sensitive moxibustion group was significantly different when compared with conventional moxibustion [RR=1.19,95% CI [1.06,1.33)] and diclofenac sodium [RR=1.47,95% CI [1.17,1.85)],but similar to that of acupuncture.The cure rate in the heat-sensitive moxibustion group was significantly different when compared with conventional moxibustion [RR=1.58,95% CI(1.04,2.40)] and diclofenac sodium [RR=1.91,95% CI(1.01,3.60)],but similar with that of acupuncture.In terms of the Japanese Orthopaedic Association scores,significant differences were noted in subjective indices,objective indices,and daily life subscales.Two trials reported that there were no adverse events over the duration of treatment.CONCLUSION:Compared with conventional moxibustion,acupuncture,and diclofenac sodium,heat-sensitive moxibustion in the treatment of LDH is superior in efficacy.Further large-scale trials are required to define the role of heat-sensitive moxibustion in the treatment of this disease.
文摘Transforaminal Percutaneous Endoscopic Discectomy(TPED) is a minimally invasive technique mainly used for the treatment of lumbar disc herniation from a lateral approach. Performed under local anesthesia, TPED has been proven to be a safe and effective technique which has been also associated with shorter rehabilitation period, reduced blood loss, trauma, and scar tissue compared to conventional procedures. However, the procedure should be performed by a spine surgeon experienced in the specific technique and capable of recognizing or avoiding various challenging conditions. In this review, pitfalls that a novice surgeon has to be mindful of, are reported and analyzed.
基金supported by the National Natural Science Foundation of China(Nos.41601208,41325001)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(No.QYZDB-SSW-DQC016)+1 种基金the State Key Laboratory of Lake Science and Environment(No.2016SKL007)the Yunnan Science and Technology Project(Nos.2016RA081,2017FD029)
文摘To assess the seasonal and spatial variations and long-term trends in water optical properties in Lake Fuxian, investigations based on field work in four seasons and a long-term analysis of data from 1980 to 2014 were conducted. The results show that there was no significant variation in the euphotic depth（Z（eu）） across the four seasons, and no significant correlations between Z（eu） and potential influencing factors in seasons other than summer, suggesting that the water itself may be a major factor regulating the Z（eu）in general. Nevertheless, significant differences in Z（eu） between the north region（NR） and the south region（SR） were observed in all seasonal tests except spring. This finding relates to a higher abundance of chromophoric dissolved organic matter（CDOM） in the NR due to runoff, especially in the rainy seasons（summer and autumn）.CDOM and its terrigenous component had an important impact on Z（eu）in summer, with the highest precipitation, and impacts from suspended solids and non-algal particles were also found in the NR in summer. The Secchi disk depth in the lake decreased clearly over the years,with significantly negative correlations with the increasing permanganate index and air temperature, implying that organic contaminants（CDOM and/or phytoplankton） are important regulators of water transparency. We estimate that the combined effects of climate warming and changes in land use and land cover are also indirect regulating factors. These findings should be considered in the protection of Lake Fuxian, owing to the importance of light penetration in aquatic ecosystems.
基金supported by the National Natural Science Foundation of China (Grant No. 10372061)the Doctor Foundation (Grant No. 20030248001)
文摘A computer code, ELANEX, including several Homogenous-Equilibrium-Model （HEM） type cavitation models, were developed, to numerically simulate natural cavitation phenomena. The effectiveness of the code was checked by cavitation flows around the disk and cylinder body for a wide range of different cavitation numbers. Cavity profiles were compared with the analytic solution of disk and empirical formulae fitted from the experiment data, and contrast between different cavitation models were fulfilled as well. The cavity length and maximal cavity diameter were found to agree well with the analytic solutions, and detailed cavity profiles were in accordance with the experimental formula. Comparison with the hemisphere headed cylinder body presented a good agreement of the pressure coefficient with the experiment data. Reasonable drag-force coefficient variation and drag-force reduction effect were obtained.
基金partially supported by the National Natural Science Foundation of China (Grant Nos. 10573022, 10973015, 11061120454and 11243003)the US National Science Foundation through grant AST-09-37523
文摘We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope （GSJT, formerly calledthe Large sky Area Multi-Object fiber Spectroscopic Telescope -- LAMOST）. The survey will obtain spectra for 2.5 million stars brighter than r 〈 19 during dark/grey time, and 5 million stars brighter than r 〈 17 or J 〈 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope＇s design constrains the optimal declination range for observations to 10~ 〈 di 〈 50~, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies： disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey will be completed in summer 2012, after a review of the results of the pilot survey.
文摘Objective： To observe the clinical efficacy of electroacupuncture and waist-building exercise in treating lumbar disk herniation. Methods： A multi-center, randomized controlled trial was adopted. Three hundred cases of lumbar disk herniations were divided into two groups, an observation group in which 149 cases were treated by electroacupuncture and waist-building exercise, and a control group in which 151 cases were treated by electroacupuncture alone. The clinical efficacy and long-term relapse rate were observed and compared between the two groups. Results： Among 149 cases in the observation group, 80 cases were cured, 57 cases improved, 12 cases failed and 4 cases relapsed; the cure rate was 53.7%, the total effective rate was 91.9% and the relapse rate was 5.0%. Among 151 cases in the control group, 74 cases were cured, 51 cases improved, 26 cases failed and 12 cases relapsed; the cure rate was 49.0%, the total effective rate was 82.8% and the relapse rate was 16.2%. There were significant differences in the cure rate and the total effective rate between the two groups （P〈0.05）. Conclusion： Combined electroacupuncture and waist-building exercise had better effects than electroacupuncture in treating lumbar disk herniation.
文摘湖水透明度能直观反映湖水清澈和混浊程度,是水体能见程度的一个量度,同时也是评价湖泊富营养化,衡量水质优劣的一个重要指标。传统地表水透明度观测主要采用塞克盘(Secchi Disk)法,这种方法不仅费时费力,而且只具有局部的代表意义。遥感技术具有快速、大面积和周期性的特点,可以有效地解决这种局限性。该文通过查干湖高光谱数据,建立透明度(Secchi Disk Depth)单波段和比值高光谱估测遥感模型,并进行验证。结果表明:利用高光谱遥感监测模型对查干湖透明度进行估算和监测,能够获取较为准确的评价结果,相对于传统监测方法具有省时省力的特点。通过对单波段估测模型和比值估测模型进行比较发现,单波段模型估测结果好于比值模型,而对数比值模型又强于单纯的比值模型。查干湖透明度高光谱定量估测模型的建立,有利于今后利用遥感影像,对查干湖水体透明度进行全面估测,对于研究和监测查干湖水体水质状况有重要意义。
文摘椎间盘退行性变（Intervertebral disk degeneration，IVDD）是一系列脊柱退行性疾病的前提和基础病理过程。这一过程不仅表现为细胞种类和形态学上的变化，更伴随有椎间盘的组织学与生化性质的改变。目前引起椎间盘退变的确切机制尚无定论。但研究发现椎间盘中的细胞因子（Cytokines，CK）在椎间盘退行性变的病理过程中可能发挥着重要的调控作用。现就细胞因子在椎间盘退变中的作用研究状况综述如下：
文摘对美国3M公司的锶特效固相萃取片(EmporeTMStrontium Rad Disk)分离水溶液中锶离子的性能进行了系统研究,包括酸度、流速、样品体积对吸附百分比的影响,吸附容量的测定,137 Cs和99 Tc在萃取片上的吸附情况等,并对萃取片上90Sr的解吸及片上90Sr的放射性测量进行了研究。在此基础上,给出了萃取片法分析环境水中90Sr的推荐程序。样品体积为1L,液闪测量时间为1h时,分析程序的最小可探测活度浓度为0.033Bq/L。最后应用一些实际环境水样对该程序进行了检验。
文摘The success of a tunnel-boring machine （TBM） in a given project depends on the functionality of all components of the system, from the cutters to the backup system, and on the entire rolling stock. However, no part of the machine plays a more crucial role in the efficient operation of the machine than its cutterhead. The design of the cutterhead impacts the efficiency of cutting, the balance of the head, the life of the cutters, the maintenance of the main bearing/gearbox, and the effectiveness of the mucking along with its effects on the wear of the face and gage cutters/muck buckets. Overall, cutterhead design heavily impacts the rate of penetration （ROP）, rate of machine utilization （U）, and daffy advance rate （AR）. Although there has been some discussion in commonly available publications regarding disk cutters, cutting forces, and some design features of the head, there is limited literature on this subject because the design of cutter- heads is mainly handled by machine manufacturers. Most of the design process involves proprietary algorithms by the manufacturers, and despite recent attention on the subject, the design of rock TBMs has been somewhat of a mystery to most end-users. This paper is an attempt to demystify the basic concepts in design. Although it may not be sufficient for a full-fledged design by the readers, this paper allows engineers and contractors to understand the thought process in the design steps, what to Look for in a proper design, and the implications of the head design on machine operation and life cycle.
基金This work was supported by the National Natural Science Foundation of China （No. 30672130 ）, China Postdoctoral Foundation （No. 20060390249 ） and National Basic Research Priorities Program of China （No. 2003CB1140）.
文摘Objective： To construct the recombinant baculovirus Ac-cytomegalovirus （CMV）-hSox9 for gene therapy of intervertebral disc degeneration. Methods： Bac-to-Bac system was used for the construction of baculovirus Ac-CMV-hSox9. The cDNA of hSox9 was first cloned into a plasmid vector under the control of CMV promotor to generate the donor plasmid pFastBacDul-green fluorescene protein （ GFP ）-CMV （pgGC）-hSox9. The resultant plasmid was transformed into DH10Bac cells and then the transformation mixture was spread on Luria-Bertani （LB） agarose culture medium containing isopropyl-β-D-thiogalactoside （IPTG）, X-gal, gentamicin, kanamycin and tetracycline. The white colonies were selected and cultured for amplification, and the hSox9 Bacmid DNA was extracted. After verification, recombinant baculovirns Ac-CMV-hSox9 was obtained through transfecting Sf 21 cells. The expression of hSox9 gene in the intervertebral disc cells in rabbits was determined by Western blotting and immunohistochemical staining. Results： Polymerase chain reaction （ PCR ） confirmed the presence of hSox9 gene in the recombinant baculovirus and the Sf 21 cells transfected by the baculovirus showed the expression of fluorescence protein. Western blotting and indicated that exogenous hSox9 disc cells. staining analysis Conclusions： The successful construction of the recombinant baculovirus Ac-CMV-hSox9 and the confirmation of the target gene expression provides a novel expression vector system for basic research and clinical treatment of intervertebral degenerative disc disease.
