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Effects of leaf N concentration and leaf area index on determining rice tillering
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《Chinese Rice Research Newsletter》 1999年第4期8-9,共2页
Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tille... Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha)and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower 展开更多
关键词 area IR Effects of leaf N concentration and leaf area index on determining rice tillering
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Clinical significance of melatonin concentrations in predicting the severity of acute pancreatitis 被引量:7
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作者 Yin Jin Chun-Jing Lin +3 位作者 Le-Mei Dong Meng-Jun Chen Qiong Zhou Jian-Sheng Wu 《World Journal of Gastroenterology》 SCIE CAS 2013年第25期4066-4071,共6页
AIM: To assess the value of plasma melatonin in predicting acute pancreatitis when combined with the acute physiology and chronic health evaluation?II?(APACHEII) and bedside index for severity in acute pancreatitis (B... AIM: To assess the value of plasma melatonin in predicting acute pancreatitis when combined with the acute physiology and chronic health evaluation?II?(APACHEII) and bedside index for severity in acute pancreatitis (BISAP) scoring systems.METHODS: APACHEII and BISAP scores were calculated for 55 patients with acute physiology (AP) in the first 24 h of admission to the hospital. Additionally, morning (6:00 AM) serum melatonin concentrations were measured on the first day after admission. According to the diagnosis and treatment guidelines for acute pancreatitis in China, 42 patients suffered mild AP (MAP). The other 13 patients developed severe AP (SAP). A total of 45 healthy volunteers were used in this study as controls. The ability of melatonin and the APACHEII and BISAP scoring systems to predict SAP was evaluated using a receiver operating characteristic (ROC) curve. The optimal melatonin cutoff concentration for SAP patients, based on the ROC curve, was used to classify the patients into either a high concentration group (34 cases) or a low concentration group (21 cases). Differences in the incidence of high scores, according to the APACHEII and BISAP scoring systems, were compared between the two groups.RESULTS: The MAP patients had increased melatonin levels compared to the SAP (38.34 ng/L vs 26.77 ng/L) (P = 0.021) and control patients (38.34 ng/L vs 30.73 ng/L) (P = 0.003). There was no significant difference inmelatoninconcentrations between the SAP group and the control group. The accuracy of determining SAP based on the melatonin level, the APACHEII score and the BISAP score was 0.758, 0.872, and 0.906, respectively, according to the ROC curve. A melatonin concentration ≤ 28.74 ng/L was associated with an increased risk of developing SAP. The incidence of high scores (≥ 3) using the BISAP system was significantly higher in patients with low melatonin concentration (≤ 28.74 ng/L) compared to patients with high melatonin concentration (> 28.74 ng/L) (42.9% vs 14.7%, P = 0.02). The incidence of high APACHEII scores (≥ 10) between the two groups was not significantly different.CONCLUSION: The melatonin concentration is closely related to the severity of AP and the BISAP score. Therefore, we can evaluate the severity of disease by measuring the levels of serum melatonin. 展开更多
关键词 PANCREATITIS Melatonin concentrations Predict CUTOFF Bedside index for severity in acute pancreatitis Acute physiology and chronic health evaluation?II
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Er^(3+) ion concentration effect on transient and steady-state behavior in Er^(3+):YAG crystal 被引量:1
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作者 Asadpour Seyyed Hossein Rahimpour Soleimani H 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期248-253,共6页
The effect of Er3+ ion concentration on transient and steady-state behavior in 45-nm Er3+ :YAG crystal is investigated. It is shown that by changing the signal field, the coherent field and the concentration of Er3... The effect of Er3+ ion concentration on transient and steady-state behavior in 45-nm Er3+ :YAG crystal is investigated. It is shown that by changing the signal field, the coherent field and the concentration of Er3+ ions in the crystal, the absorption, dispersion, and group index of the weak probe field can be adjusted. Also, it is found that the probe absorption occurs in the presence of population inversion and probe amplification is obtained in the absence of population inversion. 展开更多
关键词 Er3+ ion concentration ABSORPTION DISPERSION group index
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Characteristics Analysis of Chemical Concentration Sensor Based on Three-layer FBG 被引量:1
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作者 Zhaoxia Wu Xinyan Yu +2 位作者 Erdan Gu Zhi Kong Wenchao Li 《Optics and Photonics Journal》 2013年第2期268-271,共4页
The three-layer structure model of the fiber Bragg grating is proposed in this paper. And through experimental study and reasoning calculation to verify the three layer structure of the optical waveguide model, so the... The three-layer structure model of the fiber Bragg grating is proposed in this paper. And through experimental study and reasoning calculation to verify the three layer structure of the optical waveguide model, so the sensitivity characteristic of the Bragg wavelength to the refractive index of chemical solution is obtained. And the relationships between the concentration and the shift of Bragg wavelength of sucrose, ethanol, and Nacl solution are achieved. Finally the shifts of the Bragg wavelength with the external concentration are obtained by experiments. A kind of simple structure, small size, good stability, high sensitivity chemical concentration sensor is obtained. 展开更多
关键词 Fiber BRAGG grating(FBG) Three-layer Structure Refractive index concentration of Solution CHEMICAL SENSOR
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The Activity Concentrations, Radiation Contamination, and Hazards from Wastes and Soil Samples in Nasirabad Industrial Area, Chattogram, Bangladesh
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作者 Mohammed Didarul Alam Mojumder Mahiuddin Ahmed +2 位作者 Masud Kamal Mohammad Belal Hossen Md. Abdur Rashid 《Journal of Environmental Protection》 2020年第10期767-778,共12页
Soils and other solid wastes from industrial areas of Nasirabad, Chattogram are usually dumped or used for land development. Information about the radioactivity level presented on these soil and wastes enables one to ... Soils and other solid wastes from industrial areas of Nasirabad, Chattogram are usually dumped or used for land development. Information about the radioactivity level presented on these soil and wastes enables one to assess any possible radiological hazard to humankind by the use of such materials. A total of 37 (31 soils and 6 solid waste) samples near from different types of industries along four kilometre range were collected. The presence and activity concentrations of naturally occurred radioactive materials (NORM) and anthropogenic radionuclides in the samples were estimated using HPGe detector of 40% relative efficiency. The activity concentration of <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K were found to be ranging from 8 ± 2 to 131 ± 18.33 with an average of 21 Bq<span style="white-space:nowrap;">·</span>kg<sup>-1</sup>, 10 ± 2.69 to 133 ± 15.96 with an average of 40 Bq<span style="white-space:nowrap;">·</span>kg<sup>-1</sup> and 81 ± 22.68 to 930 ± 260.40 with an average of 449 Bq<span style="white-space:nowrap;">·</span>kg<sup>-1</sup> respectively. Besides this, some hazard indices like, the radium equivalent activity (<em>Ra<sub>eq</sub></em>), external hazard index (<em>H<sub>ex</sub></em>), internal hazard index (<em>Hi<sub>n</sub></em>), and the activity concentration index (<em>I</em><sub>y</sub>) were calculated to assess the radiation hazard in this region. The averages of calculated hazard indices were within the normal limits, except the activity concentration index, which shows elevated values. The outcomes of this study could serve as important baseline radiological data for future epidemiological studies and environmental monitoring initiatives in the study area. 展开更多
关键词 Industrial Contamination Gamma Spectrometry Activity concentration Hazard index
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Concentration Analysis of the Hungarian Mangalica Pig Stock
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作者 Krisztina Pocsai Peter Szabo Peter Balogh 《Chinese Business Review》 2012年第3期274-282,共9页
In the animal raising sector of Hungary, the indigenious and special Hungarian product called Mangalica pig has a special significance. Some descriptions were made about the species but the concentration of this segme... In the animal raising sector of Hungary, the indigenious and special Hungarian product called Mangalica pig has a special significance. Some descriptions were made about the species but the concentration of this segment has not been examined, that is why the aim of the researchers is to analyse the concentration of the Mangalica population on the basis of various statistical methods in the last 10 years. The certain concentration indexes were the following the concentration ratio, the Lorenz-curve, the Gini-coefficient, the Herfindahl-index and the redundancy index. Through the analysis we realised that from 2000 a kind of concentration started, which in case of the concentration ratio, the Lorenz-curve and the Gini-coefficient were in 2001 and 2003 of the highest ratio. The Herfindal-index and redundancy index showed that the years of 2000 and 2002 were the most significant, because of a number of large-scale producers started their activities or developed their stocks in these years. On the basis of the results, it can be stated that in the years before the application and after the recession the concentration of the stock was instable, while at the beginning of the supporting period until the crisis the appearance of large-scale firms became equal but basically according to every index the concentration in the examined years was approximately average. 展开更多
关键词 concentration indexes Mangalica pig stock concentration Lorenz-curve
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A Self-Organizing RBF Neural Network Based on Distance Concentration Immune Algorithm 被引量:4
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作者 Junfei Qiao Fei Li +2 位作者 Cuili Yang Wenjing Li Ke Gu 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第1期276-291,共16页
Radial basis function neural network(RBFNN) is an effective algorithm in nonlinear system identification. How to properly adjust the structure and parameters of RBFNN is quite challenging. To solve this problem, a dis... Radial basis function neural network(RBFNN) is an effective algorithm in nonlinear system identification. How to properly adjust the structure and parameters of RBFNN is quite challenging. To solve this problem, a distance concentration immune algorithm(DCIA) is proposed to self-organize the structure and parameters of the RBFNN in this paper. First, the distance concentration algorithm, which increases the diversity of antibodies, is used to find the global optimal solution. Secondly,the information processing strength(IPS) algorithm is used to avoid the instability that is caused by the hidden layer with neurons split or deleted randomly. However, to improve the forecasting accuracy and reduce the computation time, a sample with the most frequent occurrence of maximum error is proposed to regulate the parameters of the new neuron. In addition, the convergence proof of a self-organizing RBF neural network based on distance concentration immune algorithm(DCIA-SORBFNN) is applied to guarantee the feasibility of algorithm. Finally, several nonlinear functions are used to validate the effectiveness of the algorithm. Experimental results show that the proposed DCIASORBFNN has achieved better nonlinear approximation ability than that of the art relevant competitors. 展开更多
关键词 Distance concentration immune algorithm(DCIA) information processing strength(IPS) radial basis function neural network(RBFNN)
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Assessment of Heavy Metal Concentration and Evaluation of Health Risk of Some Vegetables Cultivated in Loumbila Farmland, Burkina Faso
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作者 Tougma Kiswendsida Alain Bambara Telado Luc +3 位作者 Doumounia Ali Derra Moumoni Inoussa Zongo Francois Zougmoré 《Journal of Environmental Protection》 2021年第12期1019-1032,共14页
Vegetables such as spinach, African eggplant, cabbage, eggplant, okra, chili peppers and tomatoes are found in our everyday foods and are the most important dietary source of nutrient. But, it becomes deleterious to h... Vegetables such as spinach, African eggplant, cabbage, eggplant, okra, chili peppers and tomatoes are found in our everyday foods and are the most important dietary source of nutrient. But, it becomes deleterious to human as well as animals as it accumulates toxic metals in their tissue when grown in contaminated soil. The mostly consumed vegetables like spinach, African eggplant (fruit and leaves), <i>Corchorus olitorius</i> leaf, <i>Amaranthus hybridus</i> leaf, cabbage, eggplant, okra, pepper and tomato were collected from Loumbila market gardening. Heavy metals copper (Cu), nickel (Ni), lead (Pb), chromium (Cr), cadmium (Cd) and zinc (Zn) were measured using atomic absorption spectrophotometer (AAS) model AANALYST 200 from PERKIN ELMER. The results of this study showed that the concentrations of lead (0.49 to 8.59 mg/kg) and zinc (20.73 to 71.29 mg/kg) in spinach, African eggplant (fruit and leaves), <i>Corchorus olitorius</i> leaf, <i>Amaranthus hybridus</i> leaf, cabbage, eggplant, okra, pepper and tomato exceeded the permissible level of FAO and WHO standard. The daily plant metal intake for Cd (0.001 - 0.015 mg/kg), Pb (0.041 - 0.730 mg/kg), and Cu (0.703 - 1.543 mg/kg) is higher than the recommended daily intake of metals but does not exceed the tolerable limit. The calculated values of the health risk indices show high values for Cd, Pb, Zn, Ni and Cu while low values are observed for Cr. Except for Cr, the IRS evaluated for all the studied metals were greater than one (IRS > 1). This implies that exposed populations are susceptible to developing diseases linked to the following metals: Cd, Pb, Zn, Ni and Cu. 展开更多
关键词 Heavy Metals concentration Daily Intake Health Risk index VEGETABLES
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Study of the relationship between dosage of oral progesterone and concentration of serum progesterone
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作者 郑婷萍 孙爱军 +5 位作者 王亚平 姜颖 张颖 陈蓉 金丽娜 郎景和 《生殖医学杂志》 CAS 2012年第B12期18-23,共6页
Objective:To explore the relationship among body mass index(BMI),dosage of progesterone(P) and serum progesterone concentration,and provide reference for the clinical use of oral progesterone. Methods:This was a rando... Objective:To explore the relationship among body mass index(BMI),dosage of progesterone(P) and serum progesterone concentration,and provide reference for the clinical use of oral progesterone. Methods:This was a random,open-label,prospective clinical trial.Eighty women meeting the criteria for enrollment were recruited from July 2010 to March 2011 in outpatient clinic of Peking Union Medical College Hospital and given oral progesterone therapy for consecutive 10 days.They were randomly assigned into four groups according to the different doses of progesterone:group A 100 mg/day,group B 200 mg/day,group C 300 mg/day and group D 400 mg/day. Results:Seventy four patients(92.5%,74/80) accomplished the study.It can be observed that administration of different dosage of P could significantly increase serum P concentration(all P<0.001).And there was a positive correlation between the increase of P concentration and dosage(r_p=0.613,P<0.001).Furthermore,the medians of the increase of serum P concentration in 4 groups were 14.71 nmol/L in group A,28.47 nmol/L in group B, 58.89 nmol/L in group C,72.69 nmol/L in group D.When BMI<24 kg/m^2(42 cases),the median of the increase of P levels was 13.90 nmol/L,37.22 nmol/L,62.55 nmol/L,and 119.02 nmol/L in group A,B,C and D, respectively,while BMI≥24 kg/m^2(32 cases),the median of increase was 8.93 nmol/L,24.82 nmol/L,24.87 nmol/L,and 63.48 nmol/L,respectively.In addition,significant difference was found only in group D between women with BMI<24 kg/m^2 and with BMI≥24 kg/m^2(P = 0.010). Conclusions;Serum progesterone levels go up linearly with the dosage increasing.The greater BMI the patient have,the larger dosage may be needed to achieve the same serum progesterone concentration.The individual dosage of oral progesterone needed can be roughly calculated in the light of the result of this study. 展开更多
关键词 个人剂量 孕激素 磷浓度 血清 口服 孕酮 激素水平 BMI
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Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain, Northwest China 被引量:6
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作者 QIANG Sheng-cai ZHANG Fu-cang +3 位作者 Miles Dyck ZHANG Yan XIANG You-zhen FAN Jun-liang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第10期2369-2380,共12页
Excessive use of nitrogen (N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary.... Excessive use of nitrogen (N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary. Previous studies mostly established critical N dilution curves based on aboveground dry matter (DM) or leaf dry matter (LDM) and stem dry matter (SDM), to diagnose the N nutrition status of the whole plant. As these methods are time consuming, we investigated the more rapidly determined leaf area index (LAI) method to establish the critical nitrogen (Nc) dilution curve, and the curve was used to diagnose plant N status for winter wheat in Guanzhong Plain in Northwest China. Field experiments were conducted using four N fertilization levels (0, 105, 210 and 315 kg ha?1) applied to six wheat cultivars in the 2013–2014 and 2014–2015 growing seasons. LAI, DM, plant N concentration (PNC) and grain yield were determined. Data points from four cultivars were used for establishing the Nc curve and data points from the remaining two cultivars were used for validating the curve. The Nc dilution curve was validated for N-limiting and non-N-limiting growth conditions and there was good agreement between estimated and observed values. The N nutrition index (NNI) ranged from 0.41 to 1.25 and the accumulated plant N deficit (Nand) ranged from 60.38 to –17.92 kg ha?1 during the growing season. The relative grain yield was significantly affected by NNI and was adequately described with a parabolic function. The Nc curve based on LAI can be adopted as an alternative and more rapid approach to diagnose plant N status to support N fertilization decisions during the vegetative growth of winter wheat in Guanzhong Plain in Northwest China. 展开更多
关键词 winter wheat leaf area index CRITICAL NITROGEN concentration NITROGEN nutrition index NITROGEN diagnosis
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The Suitability of Using Leaf Area Index to Quantify Soil Loss under Vegetation Cover 被引量:7
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作者 ZHANG Wentai YU Dongsheng +4 位作者 SHI Xuezheng WANG Hongjie GU Zhujun ZHANG Xiangyan TAN Manzhi 《Journal of Mountain Science》 SCIE CSCD 2011年第4期564-570,共7页
Soil erosion by water under forest cover is a serious problem in southern China.A comparative study was carried out on the use of leaf area index(LAI) and vegetation fractional coverage(VFC) in quantifying soil loss u... Soil erosion by water under forest cover is a serious problem in southern China.A comparative study was carried out on the use of leaf area index(LAI) and vegetation fractional coverage(VFC) in quantifying soil loss under vegetation cover.Five types of vegetation with varied LAI and VFC under field conditions were exposed to two rainfall rates(40 mm h-1 and 54 mm h-1) using a portable rainfall simulator.Runoff rate,sediment concentration and soil loss rate were measured at relatively runoff stable state.Significant negative exponential relationship(p < 0.05,R2 = 0.83) and linear relationship(p < 0.05,R2 = 0.84) were obtained between LAI and sediment concentration,while no significant relationship existed between VFC and sediment concentration.The mechanism by which vegetation canopy prevents soil loss was by reducing rainfall kinetic energy and sediment concentration.LAI could better quantify such a role than VFC.However,neither LAI nor VFC could explain runoff rate or soil loss rate.Caution must be taken when using LAI to quantify the role of certain vegetation in soil and water conservation. 展开更多
关键词 Leaf area index(LAI) Runoff steady state Sediment concentration Simulated rainfall
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Inversion of Biochemical Parameters by Selection of Proper Vegetation Index in Winter Wheat 被引量:2
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作者 HUANGWen-jiang WANGJi-hua +3 位作者 LIULiang-yun ZHAOChun-jiang WANGZhi-jie WANGJin-di 《Agricultural Sciences in China》 CAS CSCD 2004年第3期178-185,共8页
Recent studies have demonstrated the application of vegetation indices from canopy reflectedspectrum for inversion of chlorophyll concentration. Some indices are both response tovariations of vegetation and environmen... Recent studies have demonstrated the application of vegetation indices from canopy reflectedspectrum for inversion of chlorophyll concentration. Some indices are both response tovariations of vegetation and environmental factors. Canopy chlorophyll concentration, anindicator of photosynthesis activity, is related to nitrogen concentration in green vegetationand serves as an indicator of the crop response to soil nitrogen fertilizer application. Thecombination of normalized difference vegetation index (NDVI) and photochemical reflectanceindex (PRI) can reduce the effect of leaf area index (LAI) and soil background. The canopychlorophyll inversion index (CCII) was proved to be sensitive to chlorophyll concentration andvery resistant to the other variations. This paper introduced the ratio of TCARI/OSAVI to makeaccurate predictions of winter wheat chlorophyll concentration under different cultivars. Itindicated that canopy chlorophyll concentration could be evaluated by some combined vegetationindices. 展开更多
关键词 Winter wheat Canopy reflected spectrum Structure Insensitive Vegetation index Chlorophyll concentration
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Combined administration of platelet rich plasma and autologous bone marrow aspirate concentrate for spinal cord injury: a descriptive case series 被引量:3
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作者 Joseph A.Shehadi Steven M.Elzein +2 位作者 Paul Beery M.Chance Spalding Michelle Pershing 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第2期362-366,共5页
Administration of platelet rich plasma(PRP) and bone marrow aspirate concentrate(BMAC) has shown some promise in the treatment of neurological conditions;however, there is limited information on combined administratio... Administration of platelet rich plasma(PRP) and bone marrow aspirate concentrate(BMAC) has shown some promise in the treatment of neurological conditions;however, there is limited information on combined administration. As such, the purpose of this study was to assess safety and functional outcomes for patients administered combined autologous PRP and BMAC for spinal cord injury(SCI). This retrospective case series included seven patients who received combined treatment of autologous PRP and BMAC via intravenous and intrathecal administration as salvage therapy for SCI. Patients were reviewed for adverse reactions and clinical outcomes using the Oswestry Disability Index(ODI) for up to 1 year, as permitted by availability of follow-up data. Injury levels ranged from C3 through T11, and elapsed time between injury and salvage therapy ranged from 2.4 months to 6.2 years. Post-procedure complications were mild and rare, consisting only of self-limited headache and subjective memory impairment in one patient. Four patients experienced severe disability prior to PRP combined with BMAC injection, as evidenced by high(> 48/100) Oswestry Disability Index scores. Longitudinal Oswestry Disability Index scores for two patients with incomplete SCI at C6 and C7, both of whom had cervical spine injuries, demonstrated a decrease of 28–40% following salvage therapy, representing an improvement from severe to minimal disability. In conclusion, intrathecal/intravenous co-administration of PRP and BMAC resulted in no significant complications and may have had some clinical benefits. Larger clinical studies are needed to further test this method of treatment for patients with SCI who otherwise have limited meaningful treatment options. This study was reviewed and approved by the Ohio Health Institutional Review Board(IRB No. 1204946) on May 16, 2018. 展开更多
关键词 bone marrow aspirate concentrate cell-based therapy neural regeneration Oswestry Disability index platelet rich plasma spinal cord injury stem cells
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Interference of Local Government, Industrial Concentrative Rate and Corporate Diversification
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作者 LIU Shan-min 《Journal of Modern Accounting and Auditing》 2007年第2期45-55,81,共12页
This paper studies the effects of internal and external environments on the strategic decision-making of diversification using the cross-sectional data of China's 1 033 non-financial listed companies in Shenzhen and ... This paper studies the effects of internal and external environments on the strategic decision-making of diversification using the cross-sectional data of China's 1 033 non-financial listed companies in Shenzhen and Shanghai Exchange. Corporate external-environment is substituted by index of marketization and market concentrative rate, and internal-environment is substituted by governance framework and financial status. The multi-regression analysis shows that the strategic decision-making of diversification is prominently affected by external factors such as index of marketization and market concentrative rate, and is significantly negative related to the proportion of state-owned shares and corporate shares. There is no correlation between diversification and whether directors hold concurrently, or manager compensation, cash flow, and debt ratio. 展开更多
关键词 index of marketization market concentrative rate DIVERSIFICATION related diversification unrelated diversification
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一种基于迈克尔逊干涉仪的浓度/折射率在线测量系统的研究 被引量:1
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作者 陈少华 李辉 +5 位作者 周旭光 王浩 杨振清 赵卉 王芳 王麟杰 《大学物理实验》 2024年第1期27-30,共4页
浓度是表征溶液性质的重要物理参数之一。本文设计了一种基于旋转比色皿结合迈克尔逊干涉仪的浓度/折射率在线测量系统。将液体加入比色皿并旋转5°,利用CCD采集光强数据和自编的计数程序,可实时测量旋转前后干涉条纹移动数目之差,... 浓度是表征溶液性质的重要物理参数之一。本文设计了一种基于旋转比色皿结合迈克尔逊干涉仪的浓度/折射率在线测量系统。将液体加入比色皿并旋转5°,利用CCD采集光强数据和自编的计数程序,可实时测量旋转前后干涉条纹移动数目之差,并由此计算NaCl和葡萄糖溶液的折射率和浓度。对质量百分比浓度为0、10%和20%的NaCl溶液进行了折射率测量和误差分析,发现与相关理论值的相对误差仅为0.61%、0.63%和2.2%。葡萄糖溶液的浓度—折射率关系曲线也呈现出线性良好、可靠性高的特点。总之,基于迈克尔逊干涉仪的浓度/折射率在线测量系统具有测量非接触、结果可靠、高效实用的特点。 展开更多
关键词 干涉仪 旋转台 浓度 折射率 在线测量
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医疗保险视角下中国流动人口健康不平等:理论框架、水平测度与机制分析
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作者 姚强 张之恒 +1 位作者 程兆辉 李寒旋 《中国卫生政策研究》 CSCD 北大核心 2024年第11期26-34,共9页
目的:构建医疗保险视角下流动人口健康不平等框架并分析我国流动人口健康不平等。方法:以2017和2018年中国流动人口动态监测调查为数据源,基于Dover健康公平测量框架,通过集中指数及其分解探究医保视角下流动人口健康不平等现状及生成... 目的:构建医疗保险视角下流动人口健康不平等框架并分析我国流动人口健康不平等。方法:以2017和2018年中国流动人口动态监测调查为数据源,基于Dover健康公平测量框架,通过集中指数及其分解探究医保视角下流动人口健康不平等现状及生成机制。结果:收入水平较高的流动人口,在医疗服务利用、医保服务利用和健康结果方面表现更优;医疗保险参保特征是影响流动人口医疗和医保服务利用不平等的重要因素,但其对健康结果不平等的影响较小。结论:医疗保险对流动人口健康不平等的影响呈多层次特征,医疗保险制度的社会分层效应和健康社会效应差异是导致不平等的内在机制。建议围绕筹资、待遇和经办等关键环节,多措并举提升流动人口医疗保障的公平性,缩小流动人口医疗、医保服务利用及健康结果不平等。 展开更多
关键词 流动人口 医疗保险 健康不平等 集中指数
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煤自燃程序升温实验及其在实验教学中的应用
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作者 王刚 杨宝东 +2 位作者 徐浩 孙路路 黄启铭 《实验技术与管理》 CAS 北大核心 2024年第3期225-231,共7页
该文利用程序升温实验系统,对三种氧气浓度(20.9%、10%和7%)所代表的采空区散热带、氧化带、窒息带进行了煤样自燃发火实验,采集了不同温度阶段的气体产物,分析了温度及氧气浓度对气体产物浓度的影响,并对指标气体进行了详细分类和评估... 该文利用程序升温实验系统,对三种氧气浓度(20.9%、10%和7%)所代表的采空区散热带、氧化带、窒息带进行了煤样自燃发火实验,采集了不同温度阶段的气体产物,分析了温度及氧气浓度对气体产物浓度的影响,并对指标气体进行了详细分类和评估。实验结果表明:交叉点温度CPT随着氧气浓度的升高而降低,干空气的交叉点温度为144.6℃,由经验关系计算得到的CPT值与实验数据相差仅6.08%;氧气浓度越高,临界温度越低,所产生的气体浓度越高;CO气体在不同的含氧环境下都是主要的氧化产物,可作为判断煤自燃发火的主要指标,C_(2)H_(4)和C_(3)H_(6)的产生表示煤体进入加速氧化状态,可作为判断煤自燃发火的辅助指标。 展开更多
关键词 煤自燃 程序升温 氧气浓度 交叉点温度 指标体系
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福建省县域人口-经济时空分异及影响因素研究
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作者 黄耀裔 孙境蔚 +1 位作者 陈文成 赵益民 《黑河学院学报》 2024年第5期44-48,共5页
根据人口、经济及其相关指标数据,运用人口地理集中度、经济地理集中度和人口-经济匹配指数,对福建省人口与经济之间耦合关系和空间差异进行研究,并对其影响因素进行分析。结果表明:人口地理集中度在阈值为1时呈现东—西两级分异;经济... 根据人口、经济及其相关指标数据,运用人口地理集中度、经济地理集中度和人口-经济匹配指数,对福建省人口与经济之间耦合关系和空间差异进行研究,并对其影响因素进行分析。结果表明:人口地理集中度在阈值为1时呈现东—西两级分异;经济地理集中度在阈值为1时呈现闽东和闽东南集聚态势,将人口-经济匹配指数按3类划分,2010—2021年期间同类型县域逐渐呈现集聚效应,福建省县域人口-经济匹配度整体有趋好态势,但匹配程度仍有待提高,人口-经济稳定型逐渐形成一个“U”字形,与福建省“十四五”规划较为吻合,说明该划分有利于宏观决策。在今后的发展中,福建省仍要注重区域间人口与经济发展水平相协调。 展开更多
关键词 福建省 人口地理集中度 经济地理集中度 人口与经济匹配指数 时空分异
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干旱半干旱地区城市公园绿地空气负离子浓度特征及影响因素
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作者 包红光 闫晓云 +3 位作者 王波 侯秀娟 贾雨龙 秦嘉泽 《东北林业大学学报》 CAS CSCD 北大核心 2024年第5期82-88,共7页
为研究干旱半干旱地区城市公园绿地空气负离子浓度(NAIC)特征及影响因素,以呼和浩特市敕勒川公园为对象,于2020—2021年,每个季节选取晴天、晴间多云为主的天气各10 d,同步监测07:00—19:00时段,5种不同结构绿地(乔草型、乔灌型、乔木... 为研究干旱半干旱地区城市公园绿地空气负离子浓度(NAIC)特征及影响因素,以呼和浩特市敕勒川公园为对象,于2020—2021年,每个季节选取晴天、晴间多云为主的天气各10 d,同步监测07:00—19:00时段,5种不同结构绿地(乔草型、乔灌型、乔木型、灌草型、乔灌草型)及对照区(CK)空气负离子浓度及PM10、PM2.5、温度、湿度、风速、大气压强、噪声等环境指标。结果表明:不同结构绿地空气负离子浓度季节日变化有所差异;同一季节,复杂结构绿地空气负离子浓度均值较高,不同结构绿地之间空气负离子浓度均值差异不显著;同一结构绿地,夏、秋季空气负离子浓度均值显著高于春、冬季;不同结构绿地空气清洁度夏、秋季较高,空气清洁度评价指数均值分别为0.58~0.78、0.52~0.80。绿地结构、季节对空气负离子浓度影响为主效应,绿地结构×季节对空气负离子浓度交互作用不显著;除此之外,相对湿度、PM10、PM2.5是影响空气负离子浓度的主要因素。 展开更多
关键词 干旱半干旱地区 城市公园绿地 空气负离子浓度 空气清洁度评价指数
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基于分子动力学聚合物改性沥青黏附性能研究
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作者 李秀君 彭天平 但新华 《合肥工业大学学报(自然科学版)》 CAS 北大核心 2024年第4期548-554,共7页
为了增强基质沥青与集料之间界面黏附性,选取PE、SBS、SBR、PU 4种代表性聚合物对其进行改性,采用分子动力学模拟法对沥青-集料和沥青-水-集料模型进行不同工况模拟,并通过室内试验验证模拟结果。通过分析相对浓度分布曲线得到沥青极性... 为了增强基质沥青与集料之间界面黏附性,选取PE、SBS、SBR、PU 4种代表性聚合物对其进行改性,采用分子动力学模拟法对沥青-集料和沥青-水-集料模型进行不同工况模拟,并通过室内试验验证模拟结果。通过分析相对浓度分布曲线得到沥青极性组分的变化规律,研究不同温度下各改性沥青混合料黏附性并根据相对浓度参数对其机理进行分析,通过聚合物改性性能对比,得出其适用条件。结果表明:PE与沥青相溶性好,但PE改性沥青混合料水稳定性较差;SBS改性沥青能在温差较大的环境中保持较高的黏附性;SBR改性沥青低温条件下黏附性突出,且水稳定性优越,适用于低温多雨的地区;PU改性沥青综合性能较好,在高温多雨等气候条件复杂的环境中适用性较强。 展开更多
关键词 改性沥青 分子动力学 黏附性 水稳定性指标 相对浓度
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