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Clinical efficacy of intradermal type Ⅰ collagen injections in treating skin photoaging in patients from high-altitude areas
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作者 Bin Yang Ao He +6 位作者 Bin-Bin Bu Gong Zhuo Qing-Zhu Zhou Jia-Hang He Liu Liu Wen-Li Huang Xian Zhao 《World Journal of Clinical Cases》 SCIE 2024年第16期2713-2721,共9页
BACKGROUND Photoaging,a result of chronic sun exposure,leads to skin damage and pigmentation changes.Traditional treatments may have limitations in high-altitude areas like Yunnan Province.Intradermal Col Ⅰ injection... BACKGROUND Photoaging,a result of chronic sun exposure,leads to skin damage and pigmentation changes.Traditional treatments may have limitations in high-altitude areas like Yunnan Province.Intradermal Col Ⅰ injections stimulate collagen production,potentially improving skin quality.This study aims to assess the efficacy and safety of this treatment for photoaging.AIM To evaluate the efficacy and safety of intradermal typeΙcollagen(ColΙ)injection for treating photoaging.METHODS This prospective,self-controlled study investigated the impact of intradermal injections of ColΙon skin photodamage in 20 patients from the Yunnan Province.Total six treatment sessions were conducted every 4 wk±3 d.Before and after each treatment,facial skin characteristics were quantified using a VISIA skin detector.Skin thickness data were assessed using the ultrasound probes of the Dermalab skin detector.The Face-Q scale was used for subjective evaluation of the treatment effect by the patients.RESULTS The skin thickness of the right cheek consistently increased after each treatment session compared with baseline.The skin thickness of the left cheek significantly increased after the third through sixth treatment sessions compared with baseline.The skin thickness of the right zygomatic region increased after the second to sixth treatment sessions,whereas that of the left zygomatic region showed a significant increase after the fourth through sixth treatment sessions.The skin thickness of both temporal regions significantly increased after the fifth and sixth treatment sessions compared with baseline(P<0.05).These findings were also supported by skin ultrasound images.The feature count for the red areas and wrinkle feature count decreased following the treatment(P<0.05).VISIA assessments also revealed a decrease in the red areas after treatment.The Face-QSatisfaction with Facial Appearance Overall and Face-Q-Satisfaction with Skin scores significantly increased after each treatment session.The overall appearance of the patients improved after treatment.CONCLUSION Intradermal ColΙinjection improves photoaging,with higher patient satisfaction and fewer adverse reactions,and could be an effective treatment method for populations residing in high-altitude areas. 展开更多
关键词 PHOTOAGING TypeΙcollagen Face-Q high-altitude area Skin photodamage Patient satisfaction
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Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction
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作者 Ding-Han Zhu Xiong Zhang +3 位作者 Xiao-Qiang Li Peng Li Yan-Bin Wang Shuang Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第3期40-52,共13页
In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such events.These pulsed X-rays can be captured using a satellite-borne X-ray detect... In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such events.These pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric transmission.To quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction.The proposed method is an improvement over the traditional analytical method that only computes direct-transmission X-rays.The traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo method.Our improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain scenarios.Moreover,its computation time is 48,000 times faster than that of the Monte Carlo method.These results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects. 展开更多
关键词 high-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method
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Single-Arm Clinical Study of Combination Perindopril-Amlodipine Tablets in the Treatment of High-Altitude Hypertension
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作者 Miao Shao Jin Tian Jacinda Huang Wentao Wu 《Journal of Clinical and Nursing Research》 2024年第9期168-173,共6页
Objective:To evaluate the efficacy of combination perindopril/amlodipine tablets in patients with high-altitude hypertension who were previously unable to control their blood pressure with monotherapy.Methods:A total ... Objective:To evaluate the efficacy of combination perindopril/amlodipine tablets in patients with high-altitude hypertension who were previously unable to control their blood pressure with monotherapy.Methods:A total of 151 patients with high-altitude hypertension whose blood pressure remained inadequately controlled with previous monotherapy were enrolled in this study.All patients received an 8-week treatment with a combination of perindopril/amlodipine tablets,consisting of perindopril 10 mg/day and amlodipine 5 mg/day.Blood pressure measurements,including both diastolic and systolic pressures,were taken at baseline,and after 2,4,6,and 8 weeks of treatment.Results:After 8 weeks of treatment,there was a significant reduction in both average systolic and diastolic blood pressure compared to baseline(P<0.0001).Specifically,the average systolic blood pressure decreased by 24.45±13.75 mmHg,and the average diastolic blood pressure decreased by 13.37±8.40 mmHg.The overall heart rate showed no significant changes during the treatment period.Conclusion:A combination of perindopril/amlodipine tablets significantly improved blood pressure control in patients with high-altitude hypertension after 8 weeks of treatment.These results support the efficacy of combination perindopril/amlodipine as a viable treatment option for high-altitude hypertension. 展开更多
关键词 high-altitude hypertension Perindopril/amlodipine Blood pressure control Systolic and diastolic pressure reduction
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Geostructures, dynamics and risk mitigation of high-altitude and long- runout rockslides 被引量:6
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作者 Yueping Yin Bin Li +3 位作者 Yang Gao Wenpei Wang Shilin Zhang Nan Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第1期66-101,共36页
Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rock... Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas. 展开更多
关键词 ROCKSLIDE high-altitude and long-runout Sliding-prone geostructure Large-scale experimental apparatus Risk mitigation strategy Structural prevention technique
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Construction Technology of Warm Mix Asphalt Pavement in Cold High-Altitude Areas
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作者 Guangxi Wu 《Journal of Architectural Research and Development》 2023年第5期27-33,共7页
With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfor... With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfortable and smooth when traveling.High-quality pavement can significantly reduce the probability of traffic accidents.At present,there is a direct relationship between pavement quality and pavement construction operations.Carrying out pavement construction operations in cold high-altitude areas requires a reasonable selection of construction equipment and methods.The application of warm-mix asphalt pavement construction technology can ensure pavement quality.Therefore,this paper analyzes the advantages of warm-mix technology,the environmental characteristics of cold high-altitude areas,and construction preparations,and discusses the construction technology of warm-mix asphalt pavement in cold high-altitude areas in detail,to improve the overall road quality of cold high-altitude areas. 展开更多
关键词 Cold high-altitude areas Warm mix asphalt Pavement construction technology
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Settlement Control Technology of High Filled Soil-Rock Embankment in Alpine and High-Altitude Areas
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作者 Guangxi Wu 《Journal of World Architecture》 2023年第4期75-81,共7页
China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of diff... China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of different sizes in mountainous areas are unavoidable,and the settlement of high-fill embankments is usually the most concerned issue in high-fill projects.According to the current research of highway projects,most of the high embankments in mountainous areas are soil-rock mixed embankments or rock-filled embankments,and their post-construction settlements are directly related to construction technology and the type of filler used.In this paper,the problems in the settlement control of earth-filled embankment and related factors are analyzed in detail.The settlement control technology of high-fill embankment in high-cold and high-altitude areas is also discussed,so as to ensure the overall quality of high-fill embankment. 展开更多
关键词 high-altitude and cold areas High soil-rock embankment Settlement control technology
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Correlation of vascular endothelial growth factor to permeability of blood-brain barrier and brain edema during high-altitude exposure 被引量:4
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作者 Qiquan Zhou Chang'e Liu +2 位作者 Jing Wang Yunli Wang Bo Zhou 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第10期775-779,共5页
BACKGROUND: Many studies have evaluated the role of vascular endothelial growth factor (VEGF) in traumatic brain edema and hemorrhagic brain edema. OBJECTIVE: To observe the effects of VEGF expression on permeabil... BACKGROUND: Many studies have evaluated the role of vascular endothelial growth factor (VEGF) in traumatic brain edema and hemorrhagic brain edema. OBJECTIVE: To observe the effects of VEGF expression on permeability of the blood-brain barrier (BBB) during high-altitude and hypoxia exposure, and to investigate the correlation between VEGF expression and BBB permeability with regard to Evans blue staining and brain edema during high-altitude exposure. DESIGN, TIME AND SETTING: The randomized, controlled, animal study was performed at the Tanggula Etape, Central Laboratory of Chengdu Medical College, and Central Laboratory of General Hospital of Chengdu Military Area Command of Chinese PLA, China, from July 2003 to November 2004. MATERIALS: Quantitative RT-PCR kit (Sigma, USA), VEGF ELISA kit (Biosource, USA), and Evans blue (Jingchun, China) were acquired for this study. METHODS: A total of 180 Wistar rats were equally and randomly assigned to 15 groups: low-altitude (500 m), middle-altitude (2 880 m), high-altitude (4 200 m), super-high-altitude (5 000 m), 1,3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 days of super high-altitude exposure. Wistar rats were exposed to various altitude gradients to establish a hypoxia model. MAIN OUTCOME MEASURES: Brain water content was calculated according to the wet-to-dry weight ratio. BBB permeability to Evans blue was determined by colorimetric method. VEGF mRNA and protein levels in brain tissues were detected using RT-PCR and double-antibody sandwich ELISA. RESULTS: Brain water content, BBB permeability to Evans blue, and VEGF mRNA and protein levels in brain tissues increased with increasing altitude and prolonged exposure to altitude. The greatest increase was determined on day 9 upon ascending 5 000 m. Simultaneously, VEGF expression positively correlated to BBB permeability of Evans blue and brain water content (r = 0.975, 0.917, P〈 0.01). CONCLUSION: Increased VEGF protein and mRNA expression was responsible for increased BBB permeability, which may be an important mechanism underlying brain edema during high-altitude exposure. 展开更多
关键词 high-altitude blood-brain barrier PERMEABILITY vascular endothelial growth factor
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Comprehensive Marine Observing Experiment Based on High-Altitude Large Unmanned Aerial Vehicle(South China Sea Experiment2020 of the “Petrel Project”) 被引量:4
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作者 Xuefen ZHANG Liangxu LI +11 位作者 Rongkang YANG Ran GUO Xia SUN Jianping LUO Hongbin CHEN Daxin LIU Kebing TANG Wenwu PENG Xiaodong HAN Qiyun GUO Xiaoxia LI Xikun FEI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第4期531-537,共7页
In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yi... In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models. 展开更多
关键词 high-altitude large UAV MARINE typhoon unmanned surface vessel horizontal drifting radiosonde drifting buoy
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Industrial Poverty Alleviation Model in Southwestern High-altitude Mountainous Areas of China——A Case Study of Industrial Poverty Alleviation of Xueshan Township in Luquan County of Yunnan Province through Planting Codonopsis pilosula 被引量:4
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作者 Zisheng YANG Renyi YANG +5 位作者 Yanbo HE Chonghui LU En ZHU Yaohan PI Mingxin WU Ying XIONG 《Asian Agricultural Research》 2019年第3期48-54,共7页
Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and ... Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and Miao Autonomous County of Yunnan Province,located in the alpine valley of Jinsha River,is a major township with wide and deep poverty,and the incidence of poverty is up to 45. 00%. In recent years,Xueshan Township has insisted on the battle against poverty,made effort to develop the Codonopsis pilosula industry,and successfully developed a road to poverty alleviation through C. pilosula industry,and formed a unique industrial poverty alleviation model by the end of 2018,the incidence of poverty dropped to 0. 74%. Based on field survey and interview,this paper analyzes and summarizes the specific practices,main results,practical experience and promotion and application measures of the poverty alleviation model of C. pilosula planting industry in Xueshan Township,in the hope of providing certain reference for the targeted poverty alleviation in similar areas in Yunnan Province and other provinces of China. 展开更多
关键词 high-altitude mountainous areas INDUSTRIAL poverty alleviation Chinese herbal medicine PLANTING CODONOPSIS pilosula Model Xueshan Township of Luquan COUNTY
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Results of an Intentional Introduction of Artemia sinica in the High-Altitude Tibetan Lake Dangxiong Co:On a Base of Surveys in 2011 and 2013 被引量:2
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作者 JIA Qinxian Elena ANUFRIIEVA +4 位作者 LIU Shasha LIU Xifang KONG Fanjing ZHENG Mianping Nickolai SHADRIN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期74-76,共3页
1 Introduction The human population is projected to reach 9200million by 2050.A fundamental question for science is whether it is possible to increase food production to meet the demands of a human population of that ... 1 Introduction The human population is projected to reach 9200million by 2050.A fundamental question for science is whether it is possible to increase food production to meet the demands of a human population of that magnitude.It’s possible only to increase an aquaculture production.Cultivation of fish/shrimp larvae is a bottleneck in a cultivation of the different organisms.Live food 展开更多
关键词 Results of an Intentional Introduction of Artemia sinica in the high-altitude Tibetan Lake Dangxiong Co LAKE
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Exendin-4 inhibits high-altitude cerebral edema by protecting against neurobiological dysfunction 被引量:1
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作者 Zhong-Lei Sun Xian-Feng Jiang +8 位作者 Yuan-Chi Cheng Ying-Fu Liu Kai Yang Shuang-Long Zhu Xian-Bin Kong Yue Tu Ke-Feng Bian Zhen-Lin Liu Xu-Yi Chen 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第4期653-663,共11页
The anti-inflammatory and antioxidant effects of exendin-4(Ex-4) have been reported previously.However,whether(Ex-4) has anti-inflammatory and antioxidant effects on high-altitude cerebral edema(HACE) remains po... The anti-inflammatory and antioxidant effects of exendin-4(Ex-4) have been reported previously.However,whether(Ex-4) has anti-inflammatory and antioxidant effects on high-altitude cerebral edema(HACE) remains poorly understood.In this study,two rat models of HACE were established by placing rats in a hypoxic environment with a simulated altitude of either 6000-or 7000-m above sea level(MASL) for 72 hours.An altitude of 7000 MASL with 72-hours of hypoxia was found to be the optimized experimental paradigm for establishing HACE models.Then,in rats where a model of HACE was established by introducing them to a 7000 MASL environment with 72-hours of hypoxia treatment,2,10 and,100 μg of Ex-4 was intraperitoneally administrated.The open field test and tail suspension test were used to test animal behavior.Routine methods were used to detect change in inflammatory cells.Hematoxylin-eosin staining was performed to determine pathological changes to brain tissue.Wet/dry weight ratios were used to measure brain water content.Evans blue leakage was used to determine blood-brain barrier integrity.Enzyme-linked immunosorbent assay(ELISA) was performed to measure markers of inflammation and oxidative stress including superoxide dismutase,glutathione,and malonaldehyde values,as well as interleukin-6,tumor necrosis factor-alpha,cyclic adenosine monophosphate levels in the brain tissue.Western blot analysis was performed to determine the levels of occludin,ZO-1,SOCS-3,vascular endothelial growth factor,EPAC1,nuclear factor-kappa B,and aquaporin-4.Our results demonstrate that Ex-4 preconditioning decreased brain water content,inhibited inflammation and oxidative stress,alleviated brain tissue injury,maintain blood-brain barrier integrity,and effectively improved motor function in rat models of HACE.These findings suggest that Ex-4 exhibits therapeutic potential in the treatment of HACE. 展开更多
关键词 high-altitude cerebral edema EXENDIN-4 cyclic adenosine monophosphate EPACI suppressor of cytokine signaling 3 vascular endothelial growth factor HYPOXIA inflammation oxidative stress
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Multiyear Observations of Deposition-Mode Ice Nucleating Particles at Two High-Altitude Stations in India
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作者 Sandeep D.WAGH Baban NAGARE +1 位作者 Sanjay D.MORE P.Pradeep KUMAR 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第12期1437-1446,共10页
Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), an... Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), and at the Radio Astronomy Center, Ooty(RAC), were activated in deposition mode using a thermal gradient diffusion chamber to determine the INP concentrations. The measurement campaigns at IGO were conducted during 2011, 2013 and 2014, and at RAC during 2013 and 2014. When the aerosol samples were exposed to an ice supersaturation of between 5% and 23% in the temperature range-17.6?C to-22?C, the maximum INP number concentration at IGO and RAC was 1.0 L-1and 1.6 L-1, respectively.A maximum correlation coefficient of 0.76 was observed between the INP number concentration and ice supersaturation. The airmass trajectories analyzed for the measurement campaigns showed that the Arabian Desert and arid regions were the main INP contributors. Elemental analysis of particles showed the presence of Na, Cl, Si, Al, Fe, Cu, Co, Cd, S, Mn and K, as well as some rare-Earth elements like Mo, Ru, La, Ce, V and Zr. When aerosols in the size range 0.5–20 μm were considered, the fraction that acted as INPs was 1 : 104to 1 : 106at IGO, and 1 : 103to 1 : 104at RAC. The higher ratio of INPs to aerosols at RAC than IGO may be attributable to the presence of rare-Earth elements observed in the aerosol samples at RAC, which were absent at IGO. 展开更多
关键词 ice nuclei diffusion chamber AEROSOL high-altitude observation
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Minimally invasive surgery vs laparotomy in patients with colon cancer residing in high-altitude areas
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作者 Duo-Ji Suo Lang Yang-Zhen Ci Ren Zha-Xi Bian Ba 《World Journal of Clinical Cases》 SCIE 2021年第35期10919-10926,共8页
BACKGROUND Colon cancer is associated with a higher incidence among residents in highaltitude areas.Hypoxic environment at high altitudes inhibits the phagocytic and oxygen-dependent killing function of phagocytes,the... BACKGROUND Colon cancer is associated with a higher incidence among residents in highaltitude areas.Hypoxic environment at high altitudes inhibits the phagocytic and oxygen-dependent killing function of phagocytes,thereby increasing the inflammatory factors,inhibiting the body’s innate immunity and increasing the risk of colon cancer.AIM To examine the effect of minimally invasive surgery vs laparotomy in patients with colon cancer residing in high-altitude areas.METHODS Ninety-two patients with colon cancer in our hospital from January 2019 to February 2021 were selected and divided into the minimally invasive surgery and laparotomy groups using the random number table method,with 46 patients in each group.Minimally invasive surgery was performed in the minimally invasive group and laparotomy in the laparotomy group.Operative conditions,inflammatory index pre-and post-surgery,immune function index and complication probability were measured.RESULTS Operative duration was significantly longer and intraoperative blood loss and recovery time of gastrointestinal function were significantly less(all P<0.05)in the minimally invasive group than in the laparotomy group.The number of lymph nodes dissected was not significantly different.Before surgery,there were no significant differences in serum C-reactive protein,interleukin-6 and tumor necrosis factor-αlevels between the groups,whereas after surgery,the levels were significantly higher in the minimally invasive group(26.98±6.91 mg/L,146.38±11.23 ng/mL and 83.51±8.69 pg/mL vs 41.15±8.39 mg/L,186.79±15.36 ng/mL and 110.65±12.84 pg/mL,respectively,P<0.05).Furthermore,before surgery,there were no significant differences in CD3+,CD4+and CD4+/CD8+levels between the groups,whereas after surgery,the levels decreased in both groups,being significantly higher in the minimally invasive group(55.61%±4.39%,35.45%±3.67%and 1.30±0.35 vs 49.68%±5.33%,31.21%±3.25%and 1.13±0.30,respectively,P<0.05).Complication probability was significantly lower in the minimally invasive group(4.35%vs 17.39%,P<0.05).CONCLUSION Laparoscopic minimally invasive procedures reduce surgical trauma and alleviate the inflammatory response and immune dysfunction caused by invasive operation.It also shortens recovery time and reduces complication probability. 展开更多
关键词 Minimally invasive surgery LAPAROTOMY high-altitude area Colon cancer Surgical trauma Immune dysfunction
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Study on Query System of the Historical High-altitude Ground Weather Chart
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作者 GOU Si JI Li HAN Shi-gang 《Meteorological and Environmental Research》 2012年第1期5-7,13,共4页
We introduced query system of the historical high-altitude surface weather chart. Historical high-altitude surface data were converted to Grads data format. Grads as generation tool of the image, ASP was used to compi... We introduced query system of the historical high-altitude surface weather chart. Historical high-altitude surface data were converted to Grads data format. Grads as generation tool of the image, ASP was used to compile WEB page. By B/S mode, only user submitted necessary conditions for the image to server by client browser, historical high-altitude surface weather chart at corresponding time and height could be ob- tained. Without any procedures and related data, only needed client browser, user could use image conveniently to a large extent. 展开更多
关键词 Historical high-altitude ground weather chart ASP GRADS Client browser China
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High-Altitude Genetics
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作者 Maya Reid 《ChinAfrica》 2012年第7期55-55,共1页
STANDING atop a mountain thousands of meters in the air is one of the harshest of environments human can experience. But according to a study published earlier this year by a group of Chinese scientists in the journal... STANDING atop a mountain thousands of meters in the air is one of the harshest of environments human can experience. But according to a study published earlier this year by a group of Chinese scientists in the journal PLoS One, it's also a place where the mysteries of DNA may be solved. Although the building blocks of human biology take generations to change permanently, researchers are looking at how short-term functions contribute to the process. Their focus on gene expression, one such function, is particularly sharp. 展开更多
关键词 high-altitude Genetics
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大跨斜拉桥双层桁架主梁施工状态的阻力系数 被引量:1
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作者 李加武 谢泽恩 +2 位作者 李嘉煜 李宇 赵雪 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第1期14-23,共10页
针对规范中对大跨径桁架桥的双层主梁阻力系数在取值上的局限,提出一种主梁阻力系数计算方法,以施工阶段节段模型的风洞试验结果为基础,对双层桁架主梁进行模型简化后,使用CFD计算得出其三分力系数.采用不同迎风面特征尺寸,桁架片数以... 针对规范中对大跨径桁架桥的双层主梁阻力系数在取值上的局限,提出一种主梁阻力系数计算方法,以施工阶段节段模型的风洞试验结果为基础,对双层桁架主梁进行模型简化后,使用CFD计算得出其三分力系数.采用不同迎风面特征尺寸,桁架片数以及桁架间距,分析了迎风面特征尺寸对主梁的阻力系数的影响.讨论了桁架间距以及片数不同对主梁的阻力系数的影响趋势.结果表明:迎风面特征高度与特征宽度对主梁阻力系数影响的变化规律并不相同,对此提出以桁架纵高比为变量的双层桁架桥梁主梁的阻力系数拟合公式;当桁架间距较小时,桁架片数对主梁阻力系数无影响,但当桁架间距与桁架高度比值达到3时,桁架片数的变化会对主梁的阻力系数产生较大的影响. 展开更多
关键词 风洞试验 数值模拟 双层桁架梁 三分力系数 规范 计算流体动力学
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考虑温度因素对带有柔性结构的静压气体轴承稳定性影响研究
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作者 赵晓龙 张伟超 +2 位作者 孙广伟 苗张仪 董皓 《光学精密工程》 EI CAS CSCD 北大核心 2024年第14期2236-2246,共11页
为了研究静压气体轴承在工作状态下,温度对带有柔性结构的静压气体轴承柔性结构挠度变形量、流场流态及稳定性的影响规律,本文建立了带有柔性结构的静压气体止推轴承三维(3D)模型。首先,采用流-固-热多物理场耦合的计算方法,分析了工作... 为了研究静压气体轴承在工作状态下,温度对带有柔性结构的静压气体轴承柔性结构挠度变形量、流场流态及稳定性的影响规律,本文建立了带有柔性结构的静压气体止推轴承三维(3D)模型。首先,采用流-固-热多物理场耦合的计算方法,分析了工作状态下温度变化对静压气体轴承柔性结构挠度变形量、气膜流场流态及气膜稳定性的影响。然后,通过设计静压气体轴承试验台,对轴承受到载荷冲击时的振动情况进行测试,将测试结果与仿真分析结果对比,验证了仿真计算的可靠性。计算结果表明,环形柔性薄板在节流孔处的挠度变形量随温度升高而增大,当气膜间隙h=12μm的情况下,工作温度T=100℃相较于工作温度T=-20℃的挠度变形量提升了43%;其他条件相同下,随着温度的升高,气膜内气旋的范围逐渐减小;工作温度越高,受到载荷后轴承振动幅度越小。实验测试结果表明,随着工作温度的升高,轴承稳定性越高,与仿真分析结果基本一致。该研究为此类轴承在超精密领域的应用提供了理论参考。 展开更多
关键词 静压气体轴承 温度 流-固-热耦合 稳定性 计算流体力学
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基于不同加工工艺的微孔节流空气静压轴承的特性研究
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作者 于贺春 寇新俊 +4 位作者 侯玮杰 刘海腾 李广平 张国庆 王文博 《机床与液压》 北大核心 2024年第7期123-128,133,共7页
随着超精密加工技术和地面微低重力仿真的发展,相关产业对空气静压轴承的性能要求越来越高。由于传统的孔式节流器其结构特点不能完全满足实际使用的需要,节流孔直径与气膜间隙同一数量级的微孔节流空气静压轴承因其良好的刚度和承载特... 随着超精密加工技术和地面微低重力仿真的发展,相关产业对空气静压轴承的性能要求越来越高。由于传统的孔式节流器其结构特点不能完全满足实际使用的需要,节流孔直径与气膜间隙同一数量级的微孔节流空气静压轴承因其良好的刚度和承载特性,越来越受到关注。但在微孔节流器的发展过程中,微孔的加工工艺却限制了其推广应用。针对目前常用的三类微孔加工工艺,进行了理论仿真研究,通过建立不同加工工艺轴承仿真模型,运用双向流固耦合仿真方法,对比分析了基于不同加工工艺的微孔节流空气静压轴承的动静态特性。研究结果表明:锥孔类轴承承载性能优于其他两类,但耗气量大且在小间隙时刚度较差;薄壁直孔类轴承承载性能稍逊,但在大间隙下轴承刚度较佳;嵌套类轴承承载性能较差,但在小间隙下轴承刚度较大且耗气量较低。 展开更多
关键词 空气静压轴承 超精密加工 微低重力仿真 微孔节流 静动态特性
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基于MEA-BP神经网络的多孔质轴承参数优化
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作者 闫如忠 余智 《机床与液压》 北大核心 2024年第16期177-182,共6页
为了提高圆盘类多孔质静压止推轴承的静态特性,采用思维进化算法(MEA)优化反向传播(BP)神经网络,创建圆盘类多孔质静压止推轴承静态特性的预测模型,完成轴承静态承载力、静刚度以及耗气量的高精度预测,其预测误差分别低于2%、5%以及5%... 为了提高圆盘类多孔质静压止推轴承的静态特性,采用思维进化算法(MEA)优化反向传播(BP)神经网络,创建圆盘类多孔质静压止推轴承静态特性的预测模型,完成轴承静态承载力、静刚度以及耗气量的高精度预测,其预测误差分别低于2%、5%以及5%。基于此模型,以最大化静态承载力和静刚度、最小化耗气量为优化目标值,采用遗传算法对轴承的多孔质参数组合进行多目标优化,实现轴承参数的快速优化设计。优化结果表明:此轴承静态承载力提高了64.53%,静刚度提高了31.93%,耗气量降低了56.52%。 展开更多
关键词 多孔质静压止推轴承 MEA-BP神经网络 静态特性预测 多目标优化
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New dating indicates intermittent human occupation of the Nwya Devu Paleolithic site on the high-altitude central Tibetan Plateau during the past 45,000 years 被引量:2
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作者 Junyi GE Xiaoling ZHANG +9 位作者 Shejiang WANG Linhui LI Wei HE Yingshuai JIN Peiqi ZhANG Bing XU Chenglong DENG John WOLSEN Zhengtang GUO Xing GAO 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第2期531-551,共21页
The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly... The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans. 展开更多
关键词 Tibetan Plateau PALEOLITHIC Nwya Devu high-altitude adaptation Microblade industry Early Upper Paleolithic OSLdating AMS^(14)C dating
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