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Neutral Pion Electromagnetic Form Factor as a Bound System of 3 + 1 Dimensional QCD
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作者 Teruo Kurai 《Journal of Modern Physics》 2024年第7期1036-1044,共9页
We investigate a neutral pion electromagnetic form factor in momentum space and obtain Gaussian-like function for it. The characteristic form of our neutral pion electromagnetic form factor is consistent with the resu... We investigate a neutral pion electromagnetic form factor in momentum space and obtain Gaussian-like function for it. The characteristic form of our neutral pion electromagnetic form factor is consistent with the results published by Jefferson Lab Hall A Collaboration. . 展开更多
关键词 Neutral Pion Electromagnetic Form factor Gaussian-Like function
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Simulation of Haloxylon Ammodendron Stand Basic Diameter Structure Based on Fuzzy Distribution Function
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作者 Shaohua Wang Chuanqiang Liu Ting Yang 《Agricultural Sciences》 2024年第1期132-145,共14页
Based on the investigation data of 12 Haloxylon ammodendron plots in the south edge of Gurbantunggut Desert, Fuzzy distribution was introduced into the study of Haloxylon ammodendron base diameter structure fitting ac... Based on the investigation data of 12 Haloxylon ammodendron plots in the south edge of Gurbantunggut Desert, Fuzzy distribution was introduced into the study of Haloxylon ammodendron base diameter structure fitting according to the consistency between the characteristics of Fuzzy distribution function and the distribution series of cumulative percentage of stand base diameter, and the fitting precision and effect of Fuzzy distribution function were discussed. The root mean square error RMSE and determination coefficient R<sup>2</sup> values showed that Fuzzy-Γ<sub>1</sub>, Fuzzy-Γ<sub>2</sub>, Fuzzy-Γ<sub>3</sub>, Fuzzy-Γ<sub>4</sub> had good fitting performance, among which Fuzzy-Γ<sub>1</sub> had relatively high fitting precision, and its parameters were closely related to stand age and density, Fuzzy-Γ<sub>2</sub> distribution function was the second, and Fuzzy-Γ<sub>4</sub> distribution function had the worst fitting effect. By introducing a parameter c from the similarity of four distribution function formulas, a generalized Fuzzy distribution function Fuzzy-Γ<sub>5</sub> is obtained. This function shows the highest fitting accuracy. Most of the values of parameter c are near 1 or 2, which shows that the diameter distribution is mainly approximate to Fuzzy-Γ<sub>1</sub> and Fuzzy-Γ<sub>2</sub>. 展开更多
关键词 Fuzzy Distribution function Haloxylon Ammodendron Base Diameter Distribution Stand factor
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Effect of Exchange-Correlation Functional on the Structural, Mechanical, and Optoelectronic Properties of Orthorhombic RbSrBr3 Perovskite
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作者 Fatema Najrin Rabeya Bakar Sarna +3 位作者 Md. Alamin Sarker Budrun Neher Md. Mahbubur Rahman Bhuiyan Farid Ahmed 《Materials Sciences and Applications》 2024年第6期137-154,共18页
In the present study, the effect of the exchange-correlation functional on the structural, mechanical, and optoelectronic properties of orthorhombic RbSrBr3 perovskite has been investigated using various functionals i... In the present study, the effect of the exchange-correlation functional on the structural, mechanical, and optoelectronic properties of orthorhombic RbSrBr3 perovskite has been investigated using various functionals in Density Functional Theory (DFT) with the CASTEP code. The optimized lattice parameters are quite similar for all the functionals. The electronic properties have shown that RbSrBr3 perovskite is a wide direct band gap compound with a band gap energy ranging from 4.296 eV to 4.494 eV for all the functionals. The mechanical parameters like elastic constants, Young’s modulus, Shear modulus, Poisson’s ratio, Pugh’s ratio, and an anisotropic factor reveal that the RbSrBr3 perovskite has ductile behavior and an anisotropic nature which signifies the mechanical stability of the compound. The Debye temperature might withstand lattice vibration heat. High absorption coefficient (>104 cm−1), high optical conductivity, and very low reflectivity have been found in the RbSrBr3 perovskite for all functions. The computed findings on the RbSrBr3 perovskite suggested that the presented studied material is potentially applicable for photodetector and optoelectronic devices. 展开更多
关键词 Density functional Theory Mechanical Properties PHOTODETECTOR DUCTILITY Anisotropic factor
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Functional Confirmation Using a Medical X-Ray System of a Semiconductor Survey Meter
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作者 Katsunao Suzuki Toru Negishi +2 位作者 Yoh Kato Yasuhisa Kono Michiharu Sekimoto 《Open Journal of Radiology》 2024年第1期1-13,共13页
In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate ... In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate the time constant of a semiconductor survey meter and confirm the meter’s function. An additional filter was attached to the medical X-ray system to satisfy the standards of N-60 to N-120, more copper plates were added as needed, and the first and second half-value layers were calculated to enable comparisons of the facility’s X-ray system quality with the N-60 to N-120 quality values. Next, we used a medical X-ray system to measure the leakage dose and calculate the time constant of the survey meter. The functionality of the meter was then checked and compared with the energy characteristics of the meter. The experimental results showed that it was possible to use a medical X-ray system to reproduce the N-60 to N-120 radiation quality values and to calculate the time constant from the measured results, assuming actual leakage dosimetry for that radiation quality. We also found that the calibration factor was equivalent to that of the energy characteristics of the survey meter. 展开更多
关键词 Semiconductor Survey Meter functional Confirmation Medical X-Ray System Calibration factor Time Constant
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A New Thermodynamic Calculation Method for Binary Alloys Part II:Exploring the Correction Factor Function 被引量:1
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作者 XingqiuCHEN P.Rogl 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第4期328-331,共4页
A new method of revising activity values has been derived based on the so called correction factor function for binary alloys with a large difference between two components. The correction factor is a function of phys... A new method of revising activity values has been derived based on the so called correction factor function for binary alloys with a large difference between two components. The correction factor is a function of physical properties formed by the difference of two components. Its absolute value increases with the enhancement of the difference in the character of components. It can be either positive or negative and the rules for selecting the sign of correction factor have been analyzed. Results are in good agreement with the experimental values. 展开更多
关键词 Correction factor function THERMODYNAMICS Binary alloys
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Multi-factor analysis of initial poor graft function after orthotopic liver transplantation 被引量:12
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作者 Chen, Hao Peng, Cheng-Hong +5 位作者 Shen, Bai-Yong Deng, Xia-Xing Shen, Chuan Xie, Jun-Jie Dong, Wei Li, Hong-Wei 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2007年第2期141-146,共6页
BACKGROUND: In the early period of orthotopic liver transplantation (OLT), initial poor graft function (IPGF) is one of the complications which leads to primary graft non-function (PGNF) in serious cases. This study s... BACKGROUND: In the early period of orthotopic liver transplantation (OLT), initial poor graft function (IPGF) is one of the complications which leads to primary graft non-function (PGNF) in serious cases. This study set out to establish the clinical risk factors resulting in IPGF after OLT. METHODS: Eighty cases of OLT were analyzed. The IPGF group consisted of patients with alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) above 1500 IU/L within 72 hours after OLT, while those in the non-IPGF group had values below 1500 IU/L. Recipient-associated factors before OLT analyzed were age, sex, primary liver disease and Child-Pugh classification; factors analyzed within the peri-operative period were non-heart beating time (NHBT), cold ischemia time (CIT), rewarming ischemic time (RWIT), liver biopsy at the end of cold ischemia; and factors analyzed within 72 hours after OLT were ALT and/or AST values. A logistic regression model was applied to filter the possible factors resulting in IPGF. RESULTS: Donor NHBT, CIT and RWIT were significantly longer in the IPGF group than in the non-IPGF group; in the logistic regression model, NHBT was the risk factor leading to IPGF (P < 0.05), while CIT and RWIT were possible risk factors. In one case in the IPGF group, PGNF appeared with moderate hepatic steatosis. CONCLUSIONS: Longer NHBT is an important risk factor leading to IPGF, while serious steatosis in the donor liver, CIT and RWIT are potential risk factors. 展开更多
关键词 orthotopic liver transplantation poor liver function multi-factor analysis
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Improved theory of generalized meteo-ballistic weighting factor functions and their use 被引量:1
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作者 Vladimir CECH Jiri JEVICKY 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2016年第3期242-254,共13页
It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire ... It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire error budget model.Trajectories calculated under non-standard conditions are considered to be perturbed.The tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs)which are a special kind of sensitivity functions.WFFs are used for calculation of meteo ballistic elements B(ballistic wind w B,densityρB,virtual temperatureτB,pressure p B)as well.We have found that the existing theory of WFF calculation has several significant shortcomings.The aim of the article is to present a new,improved theory of generalized WFFs that eliminates the deficiencies found.Using this theory will improve methods for designing firing tables,fire control systems algorithms,and meteo message generation algorithms. 展开更多
关键词 EXTERIOR BALLISTIC Non-standard projectile trajectory Perturbation Meteoconditions Sensitivity function (Generalized) weighting (factor) function(curve) (Generalized) EFFECT function Norm EFFECT
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Relationship between brain—derived neurotrophic factor and cognitive function of obstructive sleep apnea/hypopnea syndrome patients 被引量:15
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作者 Wei-Hong Wang Guo-Ping He +2 位作者 Xu-Ping Xiao Can Gu Hua-Ying Chen 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2012年第11期906-910,共5页
Objective:To determine the relationship between the blood serum brain-derived neurotrophic factor(BDNF) level and cognitive function deterioration in patients with obstructive sleep apnea/ hypopnea syndrome(OSAHS)... Objective:To determine the relationship between the blood serum brain-derived neurotrophic factor(BDNF) level and cognitive function deterioration in patients with obstructive sleep apnea/ hypopnea syndrome(OSAHS),and to explore the possible mechanism of cognitive impairment. Methods:Twenty-eight male OSAHS patients and 14 normal males(as controls) were enrolled in the study.Polysomnography and the Montreal cognitive assessment(MoCA) were conducted. The blood serum BDNF levels were measured using ELISA.Results:The OSAHS group had significantly decreased blood serum BDNF levels compared with the control group(t=-10.912, P=0.000).The blood serum BDNF level of the subjects was significantly positively associated with the MoCA score(r=0.544,P=0.000),significantly negatively associated with the apneahypopnea index(AHI) and shallow sleep(S1+S2)(AHI:r=-0.607,P=0.000;S1+S2:r =-0.768,P= 0.000),and significantly positively associated with the lowest SaO<sub>2</sub>(LSO),slow wave sleep(S3+S4), and rapid eye movement sleep(REM)(LSO:r=0.566,P = 0.000;S3+S4:r=0.778,P=0.000;REM: r=0.575,P=0.000).Conclusions:OSAHS patients have significantly decreased blood serum BDNF levels compared with the control.Nocturnal hypoxia as well as the deprivation of slow wave sleep and REM may lead to the decreased serum BDNF level of OSAHS patients.This decreased blood serum BDNF level may contribute to the cognitive impairment in OSAHS. 展开更多
关键词 OBSTRUCTIVE SLEEP apnea/hypopnea syndrome Cognitive function BRAIN-DERIVED NEUROTROPHIC factor SLEEP
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Expression pattern and function analyses of the MADS thranscription factor genes in wheat(Triticum aestivum L.) under phosphorusstarvation condition 被引量:1
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作者 SHI Shu-ya ZHANG Fei-fei +1 位作者 GAO Si XIAO Kai 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第8期1703-1715,共13页
supported by the National Natural Science Foundation of China (31201674 and 31371618);the National Transgenic Major Program, China (2011ZX08008)
关键词 wheat(Triticum aestivum L) MADS type transcription factor Pi deprivation expression gene function
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Engineering personalized neural tissue using functionalized transcription factors
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作者 stephanie m.willerth 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第10期1570-1571,共2页
Diseases and disorders of the central nervous system often require significant interventions to restore lost function due to their com- plexity. Examples of such disorders include Parkinson's disease, Alzheimer's di... Diseases and disorders of the central nervous system often require significant interventions to restore lost function due to their com- plexity. Examples of such disorders include Parkinson's disease, Alzheimer's disease, multiple sclerosis, traumatic brain injury, and spinal cord in)ury. These diseases and disorders result trom healthy cells being destroyed, which in turn causes dysfunction in the cen- tral nervous system, The death of these cells can trigger a cascade of events that affect the rest of the body, causing symptoms that become progressively worse over time. Developing strategies for repairing the damage to the central nervous system remains chal- lenging, in part due to its inability to regenerate. 展开更多
关键词 CELL Engineering personalized neural tissue using functionalized transcription factors
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Linear QSAR Regression Models for the Prediction of Bioconcentration Factors of Chloroanilines in Fish by Density Functional Theory 被引量:16
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作者 冯长君 杨伟华 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2014年第6期830-834,共5页
Density functional theory(DFT)-B3LYP level with the 6-311G**(d,p) basis set was used to calculate a set of molecular quantum chemical descriptors of 12 chloroanilines. Quantitative structure-activity relationshi... Density functional theory(DFT)-B3LYP level with the 6-311G**(d,p) basis set was used to calculate a set of molecular quantum chemical descriptors of 12 chloroanilines. Quantitative structure-activity relationship(QSAR) models of the bioconcentration factors(BCF) of the anilines in fish were established using some of the following calculated descriptors: EHOMO, ENHOMO, ELUMO, ENLUMO, ΔE1(= ELUMO- EHOMO), ΔE2(= ENLUMO- ENHOMO), dipole moment(μ), molecular volume(V), vibrational energy of 0 K(Ev), thermodynamic energy(E), heat capacity(Cv), entropy(Sm) and the charge of benzene ring(Qph). Using the variable selection and leaps-and-bounds regression, the quantum chemical descriptors derived directly from the molecular structures were employed to develop a linear QSAR model between the bioconcentration factors(BCF) and two descriptors(Sm, ENHOMO) of 12 chloroanilines. Statistically, the most significant one is a two-parameter linear equation with the correlation coefficient(R^2) of 0.981 and cross-validated correlation coefficient(Rcv^2) of 0.967. The established QSAR model has good stability and predictability based on the results from Rcv2 of leave-one-out cross-validation, AIC, FIT and tα/2. The quantum chemical analyses were performed from two aspects of frontier molecular orbital and entropy. The results show that two structural describers are crucial to the bioconcentration activity of chloroanilines. 展开更多
关键词 CHLOROANILINES bioconcentration factor density functional theory quantum chemical describers quantitative structure-activity relationship
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Mudskipper interleukin-34 modulates the functions of monocytes/macrophages via the colony-stimulating factor-1 receptor 1 被引量:4
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作者 Hai-Yu Shen Yan Zhou +2 位作者 Qian-Jin Zhou Ming-Yun Li Jiong Chen 《Zoological Research》 SCIE CAS CSCD 2020年第2期123-137,共15页
Interleukin-34(IL-34)is a novel cytokine that plays an important role in innate immunity and inflammatory processes by binding to the colonystimulating factor-1 receptor(CSF-1R).However,information on the function of ... Interleukin-34(IL-34)is a novel cytokine that plays an important role in innate immunity and inflammatory processes by binding to the colonystimulating factor-1 receptor(CSF-1R).However,information on the function of IL-34 in fish remains limited.In the present study,we identified an IL-34 homolog from mudskippers(Boleophthalmus pectinirostris).In silico analysis showed that the mudskipper IL-34(BpIL-34)was similar to other known IL-34 variants in sequence and structure and was most closely related to an orange-spotted grouper(Epinephelus coioides)homolog.BpIL-34 transcripts were constitutively expressed in various tissues,with the highest level of expression found in the brain.Edwardsiella tarda infection significantly up-regulated the mRNA expression of BpIL-34 in the mudskipper tissues.The recombinant mature BpIL-34 peptide(rBpIL-34)was purified and used to produce anti-rBpIL-34 IgG.Western blot analysis combined with PNGase F digestion revealed that native BpIL-34 in monocytes/macrophages(MOs/MФs)was N-glycosylated.In vitro,rBpIL-34 treatment enhanced the phagocytotic and bactericidal activity of mudskipper MOs/MФs,as well as the mRNA expression of pro-inflammatory cytokines like tumor necrosis factorα(BpTNF-α)and BpIL-1βin these cells.Furthermore,the knockdown of mudskipper CSF-1R1(BpCSF-1R1),but not mudskipper BpCSF-1R2,significantly inhibited the rBpIL-34-mediated enhanced effect on MO/MФfunction.In conclusion,our results indicate that mudskipper BpIL-34 modulates the functions of MOs/MФs via BpCSF-1R1. 展开更多
关键词 Interleukin-34 MUDSKIPPER MONOCYTE/MACROPHAGE function EDWARDSIELLA tarda Colonystimulating factor-1 RECEPTOR
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On factorization of certain entire function
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作者 Feng Zixin(Department of Mathematics, Southwest China Normal University , Chongqing 630715) 《西南师范大学学报(自然科学版)》 CAS CSCD 1995年第4期356-360,共5页
OnfactorizationofcertainentirefunctionFengZixin(DepartmentofMathematics,SouthwestChinaNormalUniversity,Chong... OnfactorizationofcertainentirefunctionFengZixin(DepartmentofMathematics,SouthwestChinaNormalUniversity,Chongqing630715)Onfact... 展开更多
关键词 有穷级 整函数 分解
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Scalp electroacupuncture at the Baihui acupoint (DU 20) improves functional recovery in rats with cerebral ischemia Association with increased expression of vascular endothelial growth factors 被引量:4
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作者 Min-Wook Kim You Chul Chung +11 位作者 Hee Chan Jung Moon-Seo Park Young-Min Han Yong-An Chung Lee-So Maeng Sang-In Park Jiyeon Lim Seung Chan Kim Woo-Seok Im Jin Young Chung Minky Kim Manho Kim 《Neural Regeneration Research》 SCIE CAS CSCD 2011年第36期2822-2828,共7页
In this study, we induced cerebral infarction in rats by occluding the right middle cerebral artery, and tested the effects of electroacupuncture at the Baihui acupoint (DU 20). Motor and sensory function was tested... In this study, we induced cerebral infarction in rats by occluding the right middle cerebral artery, and tested the effects of electroacupuncture at the Baihui acupoint (DU 20). Motor and sensory function was tested using Garcia’s scale and motor weakness grading, and the expression of vascular endothelial growth factor in the brain was quantified using immunoblotting and immunohistochemistry. We found that scalp electroacupuncture at DU 20 significantly improved motor performance and sensory function in rats with stroke, and this was accompanied by an increased expression of vascular endothelial growth factor in the ischemic brain tissue and peri-ischemic area. In addition, Pearson correlation analysis showed that the improvements in functional recovery were correlated with the increased expression of vascular endothelial growth factor. 展开更多
关键词 ELECTROACUPUNCTURE cerebrovascular disorder vascular endothelial growth factor Baihui acupoint functional improvement
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A UNIVERSAL ANALYTIC POTENTIAL-ENERGY FUNCTION BASED ON A PHASE FACTOR 被引量:11
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作者 CFYu KYan DZLiu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第6期455-468,共14页
Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are o... Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are obtained adjusting the phase factors. The linear thermal expansion coefficients and Young's moduli of eleven kinds of face-centered cubic (fcc) metals - Al, Cu, Ag, etc. are calculated using the potential-energy function; the computational results are quite consistent with experimental values. Moreover, an analytic relation between the linear thermal expansion coefficients and Young's moduli of fcc metals is given using the potential-energy function. Finally, the force constants of fifty-five kinds of diatomic moleculars with low excitation state are computed using this theory, and they are quite consistent with RKR (Rydberg-Klein-Rees) experimental values. 展开更多
关键词 universal potential energy function field equation phase factor derivative renormalization linear thermal expansion coefficient Young's modulus force constant
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SYNTHESIS OF THERMAL RESPONSE FACTORS AND Z-TRANSFER FUNCTION COEFFICIENTS FOR CALCULATION OF ROOM TEMPERATURE VARIATION 被引量:1
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作者 Ding Guoliang Zhang Chunlu +1 位作者 Ge Hongming Cheng Zhzjiu(Refrigeration Technique Research Institute, Dept. of Power Machinery Engineering) 《Journal of Shanghai Jiaotong university(Science)》 EI 1996年第2期49-52,59,共5页
A new method is presented for getting the general thermal response factors and z-transfer functioncoefficients of a room by synthesizing them from the thermal response factors of different parts of the thermalinsulati... A new method is presented for getting the general thermal response factors and z-transfer functioncoefficients of a room by synthesizing them from the thermal response factors of different parts of the thermalinsulation structure. How to use the general thermal response factors and z-transfer function coefficients toca1culate the indoor air temperature variation directly is also studied. It is shown through practical use that it iseasy to program with the methods presented in this paper and the calculated results are reliable. 展开更多
关键词 thermal response factorS z-transfer function synthesis ROOM temperature VARIATION
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<i>Ratanasampil</i>(Tibetan Medicine, RNSP) Reduces <i>β</i>-Amyloid Protein (Aβ) and Pro-Inflammatory Factor Levels and Improves Cognitive Functions in Mild-to-Moderate Alzheimer’s Disease (AD) Patients Living at High Altitude 被引量:5
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作者 Aiqin Zhu Aiqi Xi +7 位作者 Guofeng Li Yinglan Li Baoxia Liao Xing Zhong Jingping Zhou Sonqin Gu Meihua Yu Yide Chu 《Journal of Behavioral and Brain Science》 2012年第1期82-91,共10页
Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory... Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory in Alzheimer’s mouse models (Tg2576) led us to investigate whether RNSP can improve cognitive functions in Alzheimer’s patients. In this study, 146 AD patients living in Qinghai province received either one gram or 0.33 gram daily of RNSP for 16 weeks. Placebo patients received Piracetam. Serum Aβ40 and Aβ42 levels were measured at the beginning of the study and after 4 and 16 weeks of treatment. Compared to the same group before treatment, MMSE scores, ADAS-cog scores and ADL scores were significantly improved (p 0.05, p > 0.05). After 16-week treatment, serum TNF-α, IL-1β, IL-6 and Aβ42 levels were significantly decreased (p < 0. 01) in the high-dose RNSP group, whereas no significant differences were found in the low-dose and placebo groups. The Aβ42/Aβ40 ratio was significantly decreased after 4-week and 16-week treatment in the high-dose RNSP group (p < 0. 05, p < 0.01). Furthermore, serum Aβ42 concentrations had a strong positive correlation with TNF-α, IL-1β and IL-6 levels. There were no observable adverse effects in either treatment or control groups. We conclude that further clinical trials of RNSP in Alzheimer disease are warranted. 展开更多
关键词 Ratanasampil (RNSP Tibetan Medicine) Alzheimer’s Disease Β-AMYLOID Peptide Aβ42/Aβ40 Ratio PRO-INFLAMMATORY factors Cognitive function
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Diet and Rat Strain as Factors in Nervous System Function and Influence of Confounders
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作者 S.KACEW R.DIXIT 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1998年第3期203-217,共15页
The necessity for understanding normal human cognitive processes and behavior, and themechanisrns which result in dysfunction in these processes are dependant on utilization of a suitable animal model. In order to dev... The necessity for understanding normal human cognitive processes and behavior, and themechanisrns which result in dysfunction in these processes are dependant on utilization of a suitable animal model. In order to develop pharmaceutical agents to alleviate mental disturbances and enable the individual to cope within the norms of society, it is incumbent upon investigators to choose a species in which pharmacokinetic principles are established and resemble those of hurnans. The choice of rats in cognition research studies has specific advantages in that these anirnals possess similar pharrnacodynamic parameters to hurnans. Further advantages include availability, low cost, ease of breeding, maintenance and an extensive literature database which enable comparisons to present findings. However, there are substantial differences in the perforrnance of various rat strains in tasks of learning, memory, attention, and responses to stress or drugs. In addition to rat strain, quantity of thed also exerts profound consequences on animal behavior. The aim of this review is to demonstrate that there are differences in the central nervous systern responsivencess of rat strains to chemicals and these could be related to factors such as source of supplier, type and quantity of feed, or season of the year. It is also evident that the genotype differs amongst strains and this may be responsible for the observed differences in CNS sensitivity to chemicals. Strain differences must be identified and taken into consideration in interpretation of assessrnent of neurobehavioural functions. It is also incumbent upon the investigators to utilize healthy (diet-controlled) animal models. 展开更多
关键词 Diet and Rat Strain as factors in Nervous System function and Influence of Confounders
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Weight Function Method for Stress Intensity Factor of Internal Surface Semi-elliptical Crack in Elliptical Holes
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作者 XIE Wei HUANG Qi-qing 《International Journal of Plant Engineering and Management》 2007年第2期93-100,共8页
The hatches for inspecting are usually designed with elliptical holes in airplane structures, so computation of the stress intensity factor of three dimensional crack at elliptical holes is pivotal for damage toleranc... The hatches for inspecting are usually designed with elliptical holes in airplane structures, so computation of the stress intensity factor of three dimensional crack at elliptical holes is pivotal for damage tolerance analysis of these structures. In this paper, weight function is derived for a two dimensional through cracks at elliptical holes by applying a compounding method. Stress intensity factor formulas for an internal surface semi-elliptical crack in elliptical holes are obtained wing the three dimensional weight function method. Stress intensity factors for an internal surface semi-elliptical crack in elliptical holes under remote tension are computed. At the same time, research on how radius of curvature for elliptical holes affect stress intensity factors was conducted. Stress intensity factors decrease when radius of curvature increases. Some results and conclusions which are of practical value are given. 展开更多
关键词 compounding method internal surface semi-elliptical crack stress intensity factor weight function elliptical holes
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SEMI-WEIGHT FUNCTION METHOD ON COMPUTATION OF STRESS INTENSITY FACTORS IN DISSIMILAR MATERIALS 被引量:2
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作者 马开平 柳春图 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第11期1241-1248,共8页
Semi_weight function method is developed to solve the plane problem of two bonded dissimilar materials containing a crack along the bond. From equilibrium equation, stress and strain relationship, conditions of contin... Semi_weight function method is developed to solve the plane problem of two bonded dissimilar materials containing a crack along the bond. From equilibrium equation, stress and strain relationship, conditions of continuity across interface and free crack surface, the stress and displacement fields were obtained. The eigenvalue of these fields is lambda. Semi_weight functions were obtained as virtual displacement and stress fields with eigenvalue?_lambda. Integral expression of fracture parameters, K Ⅰ and K Ⅱ, were obtained from reciprocal work theorem with semi_weight functions and approximate displacement and stress values on any integral path around crack tip. The calculation results of applications show that the semi_weight function method is a simple, convenient and high precision calculation method. 展开更多
关键词 dissimilar material interface crack stress intensity factor semi-weight function method plane fracture problem
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