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HIV-1 RNA Viral Load, CD4 Count and Some Haematological Parameters of People Living with HIV in the Enugu Metropolis
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作者 Izuchukwu Ibeagha Evelyn Ada Kyrian-Ogbonna +7 位作者 Felix Emelike Ekene Ibeagha Emmanuel Enyi Theresa Osarunwese Ifeyinwa Onochie-Igbinedion Harrison Abone Dorothy Ezeagwuna Chinwe Chukwuka Moses Ikegbunam 《World Journal of AIDS》 2023年第2期57-69,共13页
Background: It is widely known that the human immune-deficiency virus (HIV) induces biochemical and physiological changes in affected persons. Consequently, the overall aim of this study was to evaluate the HIV-1 RNA ... Background: It is widely known that the human immune-deficiency virus (HIV) induces biochemical and physiological changes in affected persons. Consequently, the overall aim of this study was to evaluate the HIV-1 RNA viral load, CD4 count, and certain haematological parameters among HIV treatment-na?ve subjects in the Enugu metropolis of Nigeria. Materials and Methods: A total of 252 HIV-infected, ART-native subjects (≥18) attending the University of Nigeria Teaching Hospital (UNTH) in Ituku-Ozalla, Enugu were recruited for this study and were made up of 157 (62.3%) females and 95 (37.7%) males. A total of 250 HIV-negative subjects were used as control subjects (100 males and 150 females). Blood samples were collected from all the participants and their HIV-1 status was confirmed by an immunoblot confirmatory test. Their haematological parameters and CD4 count were evaluated, while the HIV-1 viral load was only assessed on confirmed HIV-positive subjects. Results: There was female predominance (62.3%) among these HIV-positive subjects. The mean age of HIV-positive subjects was 39.16 ± 10.08 years while the mean age of the control subjects was 34.8 ± 8.6 years. The age group of 31 - 40 years (102/252 (40.5%)) constituted most of the test subjects. The total white blood cells (TWBC) (6.05 ± 5.46), lymphocyte counts (36 ± 14), haemoglobin concentrations (Hb) (9.85 ± 7.36) and the CD4 counts (242 ± 228) of the HIV-infected subjects showed a significant difference when compared with their control counterpart values of TWBC (4.5 ± 0.568), lymphocytes (39.67 ± 8.2), Hb (13.48 ± 1.5), and CD4 counts (807 ± 249) (p 0.05). Anaemia, lymphocytopenia, and thrombocytopenia were the haematological abnormalities seen in the HIV-positive subjects. HIV viral load correlated with haemoglobin concentration, CD4 count, lymphocyte count, and neutrophil count (p Conclusion: Prognostic factors, such as haemoglobin concentrations, CD4 counts, lymphocyte counts, and neutrophil counts can be used to monitor patients’ viral loads since they correlate with the latter;furthermore, age is a factor that should be considered in the management of HIV-positive patients. 展开更多
关键词 HIV-1 RNA CD4 Count Haematological parameters
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基于阵列声波测井估算碳酸盐岩储层岩石力学和地应力参数——以顺北4号带为例
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作者 刘军 黄超 +2 位作者 周磊 陈群 张生龙 《地质力学学报》 CSCD 北大核心 2024年第3期394-407,共14页
地质力学分析在油气藏勘探开发过程中发挥着重要作用,顺北油气田中—下奥陶统一间房组—鹰山组储层地应力研究相对滞后。对比分析了顺北4号带下古生界中—下奥陶统一间房组—鹰山组碳酸盐岩不同类型储层的岩石力学和地应力特征,同时探... 地质力学分析在油气藏勘探开发过程中发挥着重要作用,顺北油气田中—下奥陶统一间房组—鹰山组储层地应力研究相对滞后。对比分析了顺北4号带下古生界中—下奥陶统一间房组—鹰山组碳酸盐岩不同类型储层的岩石力学和地应力特征,同时探讨了微观颗粒结构对碳酸盐岩储层地应力和岩石力学参数的控制作用,为顺北地区超深层碳酸盐岩储层评价提供了基础地质依据。基于弹簧组合模型,通过岩石力学实验和阵列声波测井确定了岩石力学和地应力特征,通过铸体薄片和X射线CT扫描表征碳酸盐岩的微观孔隙结构。研究结果表明:顺北4号带一间房组—鹰山组杨氏模量分布在50~89 GPa,抗压强度在99~136 MPa,泊松比在0.25~0.32;地层最大水平主应力为200~225 MPa,最小水平主应力为125~160 MPa。一间房组—鹰山组碳酸盐岩不同类型储层的岩石力学参数和地应力存在明显差异,从Ⅰ类、Ⅱ类、Ⅲ类到非储层段碳酸盐岩的杨氏模量、抗压强度和最大水平主应力明显增大,而泊松比和最小水平主应力变化不大。相比于一间房组—鹰山组泥晶灰岩,砂屑-生屑灰岩方解石颗粒较大,颗粒黏结程度降低,导致岩石抗压强度和杨氏模量减小;砂屑-生屑灰岩部分方解石颗粒呈次圆状或圆状,颗粒三维空间球度较大,颗粒之间咬合作用减弱,使得岩石的抗压强度和杨氏模量减小;砂屑-生屑灰岩存在大量的孔隙和裂缝,灰岩易沿着潜在的微裂缝面或者颗粒接触面摩擦滑动甚至破裂,同样导致岩石抗压强度和杨氏模量减小。此外,一间房组—鹰山组泥晶灰岩受热液作用影响,部分白云石交代为石英,导致泥晶灰岩的抗压强度和杨氏模量增加。岩石的宏观力学特征和岩石力学参数受岩石微观颗粒结构的制约,一间房组—鹰山组杨氏模量、抗压强度和最大水平主应力低值区即为顺北4号带优势储层发育区带。 展开更多
关键词 顺北4号带 碳酸盐岩 岩石力学参数 地应力
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SF_(6)替代气体C_(4)F_(7)N/CO_(2)喷口灭弧性能分析
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作者 李静 荐雯 +1 位作者 曹云东 王成丽 《高压电器》 CAS CSCD 北大核心 2024年第9期92-98,共7页
近几年,C_(4)F_(7)N/CO_(2)混合气体因为较低的温室效应和优异的绝缘性能受到广泛关注,但是C_(4)F_(7)N的电弧分断性能实验昂贵、费时,所以文中以SF_(6)和C_(4)F_(7)N/CO_(2)混合气体为研究对象,建立了在固定开距直流电源条件下的电弧... 近几年,C_(4)F_(7)N/CO_(2)混合气体因为较低的温室效应和优异的绝缘性能受到广泛关注,但是C_(4)F_(7)N的电弧分断性能实验昂贵、费时,所以文中以SF_(6)和C_(4)F_(7)N/CO_(2)混合气体为研究对象,建立了在固定开距直流电源条件下的电弧模型。通过电弧累计能量和电导的计算结果分析SF_(6)和C_(4)F_(7)N/CO_(2)混合气体的灭弧性能,通过对径向温度、物性参数的分析和能量运输的计算分析SF_(6)和C_(4)F_(7)N/CO_(2)混合气体的换热机理研究。结果表明,C_(4)F_(7)N/CO_(2)混合气体的电弧特性比较接近SF_(6)气体,可以通过适当提高气压和C_(4)F_(7)N气体占比来提高C_(4)F_(7)N/CO_(2)混合气体的灭弧性能,C_(4)F_(7)N/CO_(2)混合气体的能量交换方式也和SF_(6)气体比较接近,说明C_(4)F_(7)N/CO_(2)混合气体有较好的灭弧性能,为其在SF_(6)替代气体断路器的应用提供参考。 展开更多
关键词 SF_(6)替代气体 电弧 C_(4)F_(7)N/CO_(2)混合气体 物性参数
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Determination of Electron Swarm Parameters in Pure CHF_3 and CF_4 by a Time-Resolved Method 被引量:5
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作者 肖登明 邓云坤 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第1期25-29,共5页
The density-normalized effective ionization coefficient (α - η)/N (α and η are the ionization and attachment coefficients respectively), the electron drift velocity Ve and density- normalized longitudinal diff... The density-normalized effective ionization coefficient (α - η)/N (α and η are the ionization and attachment coefficients respectively), the electron drift velocity Ve and density- normalized longitudinal diffusion coefficient NDL in trifluoromethane (CHF3) and carbon tetraflu- oride (CF4) were measured using a pulsed Townsend technique over a wide E/N range. From the plots of (α- η)/N, we have derived the limiting field strength, (E/N)nm, which is valid for the analysis of insulation characteristics and applications to power equipment. Comparisons of the electron swarms parameters between CHF3 and CFa have been performed, and the global warming potential (GWP) is also taken into account. 展开更多
关键词 electron swarm parameters CHF3 CF4 pulse Townsend discharge GWP
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Application of response surface methodology to optimize process parameters in friction welding of Ti-6Al-4V and SS304L rods 被引量:3
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作者 R.KUMAR M.BALASUBRAMANIAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第11期3625-3633,共9页
A method to decide near optimal settings of the process parameters in friction welding was proposed.The success of the friction welding process is based on various input parameters like friction pressure,friction time... A method to decide near optimal settings of the process parameters in friction welding was proposed.The success of the friction welding process is based on various input parameters like friction pressure,friction time,upset pressure and upset time and output parameters like tensile strength,hardness and material loss.Ti-6Al-4V and SS304L(SS) materials were joined by friction welding process using interlayer techniques.The Box-Behnken design and response surface methodology(RSM) were applied to deciding the number of experiments to be performed and identify the optimum process parameters for obtaining better joint strength.The results were highly encouraging.Join strength of 523 MPa was obtained at a friction pressure of 12 N/mm^2,upset pressure of40 N/mm^2,friction time of 1.2 s and upset time of 7 s. 展开更多
关键词 friction welding welding parameters TI-6AL-4V SS304L copper interlayer
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Investigation of the performance of CF3I/c-C4F8/N2 and CF3I/c-C4F8/CO2 gas mixtures from electron transport parameters 被引量:5
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作者 Ruishuang ZHONG Su ZHAO +4 位作者 Dengming XIAO Hui WANG Xiuchen JIANG Zhongmin YU Yunkun DENG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第5期44-51,共8页
CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas m... CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment. 展开更多
关键词 CF3I/c-C4F8/N2 gas mixtures CF3I/c-C4F8/CO2 gas mixtures Boltzmann method electron transport parameters synergistic effect
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Calculating Hamiltonian parameters for Yb^(3+) in a low-symmetry lattice site,and fitting the structure and levels of Yb^(3+) :TaO_4 (= Gd,Y,and Sc) 被引量:1
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作者 张庆礼 宁凯杰 +4 位作者 丁丽华 刘文鹏 孙敦陆 江海河 殷绍唐 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第6期522-529,共8页
An iterative method is used to find the values of the Hamiltonian parameters for Yb^3+ in a given low-symmetry crys- talline site. Samples of Yb^3+ :RETaO4 (RE = Gd, Y, and Sc) were prepared and their structures ... An iterative method is used to find the values of the Hamiltonian parameters for Yb^3+ in a given low-symmetry crys- talline site. Samples of Yb^3+ :RETaO4 (RE = Gd, Y, and Sc) were prepared and their structures were determined. Based on the obtained structural data, their orbital-spin parameters and crystal field parameters were fitted by the superposition model (SM). Using the crystal field parameters obtained by the SM fitting as the initial parameters, the Hamiltonian parameters were fitted iteratively. The calculated and experimental energy levels for Yb^3+:RETaO4 are consistent, and the maximal mean-root-square deviation is only 2.84 cm^- 1, indicating that the method is effective to determine the Hamiltonian parameters of Yb^3+ in low-symmetry crystalline sites. 展开更多
关键词 crystal field parameter rare earth X-ray diffraction Yb^3+ :RETaO4
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Spectral Parameters of Nd^(3+) Ion in Nd^(3+):NaGd(MoO_4)_2 Crystal 被引量:1
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作者 李修芝 王国富 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第4期392-394,共3页
The spectral parameters of Nd^3+ ions in Nd^3+-doped NaGd(MoO4)2 crystal have been investigated based on Judd-Ofelt theory and obtained as follows: The intensity parameters Ωeff are Ω2 = 24.77×10^20, Ω4 =... The spectral parameters of Nd^3+ ions in Nd^3+-doped NaGd(MoO4)2 crystal have been investigated based on Judd-Ofelt theory and obtained as follows: The intensity parameters Ωeff are Ω2 = 24.77×10^20, Ω4 = 7.31×10^-20 and Ω6 = 6.91×10^-20 cm^2. The radiative lifetime is 100 μs, and the quantum efficiency is 93.9%. The fluorescence branch ratios were calculated to be β1 = 0.441, β2 = 0.469,β3 = 0.086 and β4=0.004. 展开更多
关键词 spectral parameters Judd-Ofelt theory Nd^3+:NaGd(MoO4)2 solid-state laser materials
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胃癌患者血清胃泌素释放肽前体、鳞癌相关抗原和糖类抗原72-4的变化及意义
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作者 胡飞 张克昌 +2 位作者 陈峰 童正喜 涂秀 《实用临床医药杂志》 CAS 2024年第12期46-50,共5页
目的探讨胃癌患者血清胃泌素释放肽前体(ProGRP)、鳞癌相关抗原(SCC)及糖类抗原72-4(CA72-4)水平变化及临床意义。方法选取68例胃癌患者(胃癌组)、37例胃部良性病变患者(胃部良性病变组)、30例健康受试者(非胃部疾病组)作为研究对象。比... 目的探讨胃癌患者血清胃泌素释放肽前体(ProGRP)、鳞癌相关抗原(SCC)及糖类抗原72-4(CA72-4)水平变化及临床意义。方法选取68例胃癌患者(胃癌组)、37例胃部良性病变患者(胃部良性病变组)、30例健康受试者(非胃部疾病组)作为研究对象。比较3组研究对象入院时血清ProGRP、SCC、CA72-4水平;分析胃癌组患者血清ProGRP、SCC、CA72-4水平与病理参数的关系;对出院后胃癌组患者随访24个月,采用多因素Logistic回归分析明确胃癌患者随访预后的影响因素,绘制受试者工作特征(ROC)曲线并计算曲线下面积(AUC),分析血清ProGRP、SCC、CA72-4对胃癌患者随访期间死亡的预测效能。结果胃癌组血清ProGRP、SCC、CA72-4水平高于胃部良性病变组和非胃部疾病组,胃部良性病变组血清ProGRP、CA72-4水平高于非胃部疾病组,差异有统计学意义(P<0.05);胃癌组中,TNM分期为Ⅲ~Ⅳ期、组织学分级为中低分化、有淋巴结转移患者血清ProGRP、CA72-4水平分别高于Ⅰ~Ⅱ期、高分化、无淋巴结转移患者,组织学分级为中低分化患者血清SCC水平高于高分化患者,差异有统计学意义(P<0.05)。随访24个月,胃癌组存活49例(存活组)、死亡19例(死亡组),死亡组患者入院时血清ProGRP、SCC、CA72-4水平均高于存活组,差异有统计学意义(P<0.05)。多因素Logistic回归分析结果显示,血清ProGRP、SCC、CA72-4均为胃癌患者随访预后的独立影响因素(P<0.05);血清ProGRP、SCC、CA72-4对胃癌患者随访期间死亡均有良好的预测效能(AUC=0.766、0.705、0.828),且三者联合的预测效能更佳(AUC=0.899)。结论胃癌患者血清ProGRP、SCC、CA72-4水平异常升高(与TNM分期、组织学分级、淋巴结转移状态有关),三者联合检测对患者随访期间死亡具有很好的预测效能。 展开更多
关键词 胃癌 胃泌素释放肽前体 鳞癌相关抗原 糖类抗原72-4 病理参数
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GX4CrNi13-4马氏体不锈钢激光熔覆工艺参数优化和仿真模拟
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作者 张华炜 何凌欢 +2 位作者 侯娟 李家民 黄爱军 《材料工程》 EI CAS CSCD 北大核心 2024年第7期83-93,共11页
为提升激光熔覆质量,建立以激光功率、扫描速度及送粉量为主要工艺参数的有限元分析过程,减少熔覆工艺参数优化的研发周期和经济成本。通过温度场和应力场模拟GX4CrNi13-4马氏体不锈钢激光熔覆数据对照实验结果的方法,验证不同参数下的... 为提升激光熔覆质量,建立以激光功率、扫描速度及送粉量为主要工艺参数的有限元分析过程,减少熔覆工艺参数优化的研发周期和经济成本。通过温度场和应力场模拟GX4CrNi13-4马氏体不锈钢激光熔覆数据对照实验结果的方法,验证不同参数下的成形质量,优化激光熔覆工艺参数。结果表明:为避免基体熔穿和高质量致密度,激光功率的调整范围应控制在1800~2000 W之间;增加送粉量可以有效降低温度和残余应力。3个工艺参数中激光功率是主要调控参数,对熔覆质量影响最大。综合致密度分析和显微硬度测试评估不同参数下样品的熔覆质量和残余应力分布,发现最佳工艺参数组合为激光功率1800 W、扫描速度10 mm/s以及送粉量10 g/min。实验结果与应力场模拟的趋势一致,进一步验证模拟数据的准确性。 展开更多
关键词 GX4CrNi13-4马氏体不锈钢 工艺参数优化 有限元模拟 温度场 应力场
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超声造影及TgAb、SP1和KLF4表达水平对分化型甲状腺癌临床分期的诊断价值
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作者 张文涛 董汉华 +1 位作者 赵亚鹏 康志强 《实用癌症杂志》 2024年第5期701-704,709,共5页
目的探讨超声造影及血清甲状腺球蛋白抗体(TgAb)、特异性蛋白1(SP1)和Krüppel样因子4(KLF4)基因表达对分化型甲状腺癌(DTC)的诊断价值,并分析其相关性。方法采用便利抽样法选取手术治疗的130例DTC患者为研究对象,术前使用彩色多普... 目的探讨超声造影及血清甲状腺球蛋白抗体(TgAb)、特异性蛋白1(SP1)和Krüppel样因子4(KLF4)基因表达对分化型甲状腺癌(DTC)的诊断价值,并分析其相关性。方法采用便利抽样法选取手术治疗的130例DTC患者为研究对象,术前使用彩色多普勒超声诊断仪进行甲状腺检查,记录超声造影参数造影剂达峰时间(TIP)、平均通过时间(MTT)以及峰值强度(PI)。术前采集患者晨起空腹静脉血,检测血清TgAb、SP1和KLF4水平。收集患者术后病理标本,根据AJCC分级系统对DTC临床分期进行评估,比较不同分期患者的超声造影参数与血清TgAb、SP1、KLF4表达水平的差异;采用Spearman法进行DTC临床分期与TIP、MTT、PI、TgAb、SP1、KLF4水平相关性分析;绘制受试者工作特征曲线(ROC)分析超声造影与血清TgAb、SP1、KLF4水平对DTC临床分期的诊断效能。结果Ⅰ期、Ⅱ期、Ⅲ期和Ⅳ期,DTC患者TIP、MTT、PI和KLF4 mRNA相对表达水平依次降低,血清TgAb水平和SP1mRNA相对表达水平依次升高(P<0.001)。DTC临床分期与TIP、MTT、PI和血清KLF4 mRNA水平负相关(P<0.05),与血清TgAb、SP1 mRNA水平正相关(P<0.05)。超声造影、TgAb水平、SP1与KLF4 mRNA表达水平单一及联合诊断DTC的AUC依次为0.808、0.715、0.689、0.667、0.853,其中联合诊断AUC最大。结论DTC临床分期与超声造影参数TIP、MTT、PI和血清KLF4表达呈负相关关系,与血清TgAb、SP1表达呈正相关关系,将超声造影与血清TgAb、SP1和KLF4联合用于鉴别诊断DTC临床分期的效能最高。 展开更多
关键词 分化型甲状腺癌 临床分期 超声造影参数 甲状腺球蛋白抗体 特异性蛋白1 Krüppel样因子4
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Haematology Parameters of Apparently Healthy Prospective Whole Blood Donors in a Nigerian Hospital Setting
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作者 Taiwo Modupe Balogun Kingsley Aile +2 位作者 Athanasius Chika Nnamani Olayinka Saidat Kareem Adenekan Salu 《Open Journal of Blood Diseases》 2023年第2期59-68,共10页
Background: Adequate selection of a prospective whole blood donor protects his health and safety of the recipient. Objectives: The main objective of this study was to determine the haematology parameters of apparently... Background: Adequate selection of a prospective whole blood donor protects his health and safety of the recipient. Objectives: The main objective of this study was to determine the haematology parameters of apparently healthy prospective whole blood donors. Participants and Methods: This was a hospital based prospective study carried out from August to October 2020 at the blood transfusion unit of the Lagos State University Teaching Hospital (LASUTH), Ikeja, Nigeria. A structured pretested questionnaire was used for data collection. The socio demographic status and the haematology parameters of apparently healthy prospective whole blood donors who tested negative for HIV, hepatitis B and C markers were captured. Obtained data were analysed with the statistical package for the social scientist software version 20. Results: One hundred male (97.1%) and three female (2.9%) apparently healthy prospective whole blood donors were studied. The median age of study subjects was 30 years. Obtained median haematology parameter values were 13 g/dl, 40%, 4.9/nl and 203.9/nl for haemoglobin concentration, haematocrit, total white cell and platelet counts respectively. The median values for the mean corpuscular haemoglobin concentration (MCHC), mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) of participants were 32.6 g/dl, 27.7 pg and 85.7 fl respectively. Observed prevalence of subnormal haematology parameters for haemoglobin concentration, total white cells, platelets were 12.6%, 25.2%, and 13.6% respectively. Also subnormal values for MCHC, MCH, MCV were 11.7%, 26.2%, and 16.5% respectively among prospective whole blood donors in this study. No higher than normal haematology parameter values were observed. Median values for erythrocyte sedimentation rate was 8.4 mm/hr. Conclusion: A significant percentage of apparently healthy prospective whole blood donors had subnormal haematology parameters values. Obtained normal values in our study are comparable with local reference range reports from previous studies in Nigeria and other parts of Africa. 124947 . 展开更多
关键词 Whole Blood Donors Selection Haematology parameters CD4 +ve T Lymphocyte Counts Nigeria
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Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl_6)^(4-) coordination complex in MCl:V^(2+) (M=Na,K,Rb) systems
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作者 祁林 邝小渝 +2 位作者 柴瑞鹏 段美玲 张彩霞 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1586-1593,共8页
By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl... By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl:V2+ (M=Na, K, Rb) systems at 77K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V2+ systems. Meanwhile, it finds that the structure parameters R1, R2 and |△R|( = R1 - R2) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed. 展开更多
关键词 complete energy matrix EPR parameters (VCl6)4- coordination complex local structure
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Investigation of radiation influences on electrical parameters of 4H-SiC VDMOS
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作者 Li Sheng Xu Zhiyuan +2 位作者 Wei Jiaxing Liu Siyang Sun Weifeng 《Journal of Southeast University(English Edition)》 EI CAS 2018年第4期474-479,共6页
The radiation influences on electrical parameters of4H-SiC vertical double-implanted metal-oxide-semiconductor field effect transistor( VDMOS) are studied. By simulations on SRIM software and SILVACO software, the ele... The radiation influences on electrical parameters of4H-SiC vertical double-implanted metal-oxide-semiconductor field effect transistor( VDMOS) are studied. By simulations on SRIM software and SILVACO software, the electrical parameters shifts of the device with defects in different regions are observed. The results indicate that the defects in different regions induced by radiations lead to different degradations of the electrical parameters. Non-ionization bulk defects in the JFET region make the drain-source on-state resistance Rdson increase,and those near the impact ionization center make the breakdown voltage Vbreakdownincrease. Moreover,the radiationinduced SiC/SiO2 interface defects,known as negative interface charges or positive interface charges,influence the electrical parameters significantly as well. The positive interface charges along the SiC/SiO2 interface above the channel region lead to a decrease in threshold voltage Vth,Rdsonand Vbreakdown,while positive interface charges along the Si C/Metal interface above the main junction of the terminal only leads to the decrease in Vbreakdown. The negative interface charges along the SiC/SiO2 interface above the channel region can make Vth,Rdsonand Vbreakdownincrease. 展开更多
关键词 4H-SiC VDMOS RADIATION TRAP interface charge electrical parameters
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Optical parameters and energy levels splitting of Ho^(3+) in Ho^(3+): GdVO_4
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作者 王策 陈晓波 +8 位作者 张春林 张蕴芝 刘金英 王亚非 刘大禾 杜帅 徐小灵 王磊 李崧 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第12期4656-4664,共9页
Ho^3+ : GdVO4 is a new laser material suitable for high-power laser systems. In this paper we measure the absorption spectra of Ho^3+ in the sample Ho^3+: GdVO4. The intensity parameters are calculated by using t... Ho^3+ : GdVO4 is a new laser material suitable for high-power laser systems. In this paper we measure the absorption spectra of Ho^3+ in the sample Ho^3+: GdVO4. The intensity parameters are calculated by using the Judd-Ofelt theory. Some predicted spectroscopic parameters, such as the spontaneous radiative transition rate, branching ratio and integrated emission cross section are dealt with. And we also compare the optical parameters with those of other materials. From these results, it is found that there are many transitions which have large oscillator strengths and large integrated emission cross sections. Especially the transitions such as ^5 F4 → ^5 I 8, ^5 S2→^5 I8, ^5 F5 → ^5 I8 and ^5 I7 →^ 5 I8 are useful in solid-state lasers and other fields. Finally, we discuss the splitting of the energy levels of Ho^3+ in the crystal GdVO4 based on the group theory. 展开更多
关键词 Ho^3+: GdVO4 absorption spectrum intensity parameters laser material
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Spectral Parameters of Nd^(3+) Ion in Nd^(3+):KLu(WO_4)_2 Crystal
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作者 TANGLi-Yong WANGGuo-Fu 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第4期383-386,共4页
The spectral parameters of Nd3+ ions in Nd3+:Klu(WO4)2 crystal were calculated based on Judd-Ofelt theory and obtained as follows: for the oscillator strengths ?λ: ?2 = 7.5029×10-20 cm2, ?4 = 7.1837×10-20... The spectral parameters of Nd3+ ions in Nd3+:Klu(WO4)2 crystal were calculated based on Judd-Ofelt theory and obtained as follows: for the oscillator strengths ?λ: ?2 = 7.5029×10-20 cm2, ?4 = 7.1837×10-20 cm2 and ?6 = 3.1189×10-20 cm2; the radiative lifetime is 123 μs; the quantum efficiency is equal to 64.55%; and β1 = 0.5498, β2 = 0.3943, β3 = 0.0551 and β4 = 0.0027 for the fluorescence branch ratios. 展开更多
关键词 spectral parameters Nd3+:KLu(WO4)2 crystal Judd-Ofelt theory
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Estimations of Land Surface Characteristic Parameters and Turbulent Heat Fluxes over the Tibetan Plateau Based on FY-4A/AGRI Data
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作者 Nan GE Lei ZHONG +5 位作者 Yaoming MA Yunfei FU Mijun ZOU Meilin CHENG Xian WANG Ziyu HUANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第8期1299-1314,共16页
Accurate estimates of land surface characteristic parameters and turbulent heat fluxes play an important role in the understanding of land-atmosphere interaction. In this study, Fengyun-4A (FY-4A) Advanced Geostationa... Accurate estimates of land surface characteristic parameters and turbulent heat fluxes play an important role in the understanding of land-atmosphere interaction. In this study, Fengyun-4A (FY-4A) Advanced Geostationary Radiation Imager (AGRI) satellite data and the China Land Data Assimilation System (CLDAS) meteorological forcing dataset CLDAS-V2.0 were applied for the retrieval of broadband albedo, land surface temperature (LST), radiation flux components, and turbulent heat fluxes over the Tibetan Plateau (TP). The FY-4A/AGRI and CLDAS-V2.0 data from 12 March 2018 to 30 April 2018 were first used to estimate the hourly turbulent heat fluxes over the TP. The time series data of in-situ measurements from the Tibetan Observation and Research Platform were divided into two halves-one for developing retrieval algorithms for broadband albedo and LST based on FY-4A, and the other for the cross validation. Results show the root-mean-square errors (RMSEs) of the FY-4A retrieved broadband albedo and LST were 0.0309 and 3.85 K, respectively, which verifies the applicability of the retrieval method. The RMSEs of the downwelling/upwelling shortwave radiation flux and downwelling/upwelling longwave radiation flux were 138.87/32.78 W m^(−2) and 51.55/17.92 W m^(−2), respectively, and the RMSEs of net radiation flux, sensible heat flux, and latent heat flux were 58.88 W m^(−2), 82.56 W m^(−2) and 72.46 W m^(−2), respectively. The spatial distributions and diurnal variations of LST and turbulent heat fluxes were further analyzed in detail. 展开更多
关键词 FY-4A/AGRI land surface characteristic parameters turbulent heat fluxes Surface Energy Balance System model Tibetan Plateau
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Computation of Energy, Intensity and Thermodynamic Parameters for the Interaction of Ln(III) with Nucleic Acid: Analysis of Structural Conformations, Chemical Kinetics and Thermodynamic Behaviour through 4f-4f Transition Spectra as Probe
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作者 N. Bendangsenla T. Moainla +1 位作者 Juliana Sanchu M. Indira Devi 《Journal of Materials Science and Chemical Engineering》 2018年第7期169-183,共15页
Nucleosides and Nucleotides are polydentate ligands, offering potential binding sites for metal ions. Energy interaction parameters: Slater Condon Fk (cm-1), Spin Orbit interaction ξ4f? (cm-1), Nephelauxetic Ratio (... Nucleosides and Nucleotides are polydentate ligands, offering potential binding sites for metal ions. Energy interaction parameters: Slater Condon Fk (cm-1), Spin Orbit interaction ξ4f? (cm-1), Nephelauxetic Ratio (β), Bonding (b1/2) and Covalency (δ) parameter for the interaction of Pr(III) with Nucleoside and Nucleotide are evaluated to study the mode of binding of the Nucleic Acid Components (Guanosine and Guanosine Triphosphate) with Pr(III). Further Intensity Parameters like Oscillation Strength and Judd Ofelt Parameter (T2, T4, T6) have been evaluated to investigate degree of inner or outer sphere co-ordination of Pr(III) with Nucliec Acid ligands. Comperative Absorption Spectra in different solvents substantiate the informations, gathered from the evaluated values of both energy interaction and intensity parameters. Further evaluation of Thermodynamic parameters (ΔG, ΔH and ΔS) through Kinetic studies enable to provide the detailed information about the reaction pathways and thermodynamic behavour of the complexation process of neucleosides and nucleotides with Pr(III) and Ca2+. 展开更多
关键词 Nucleic Acid 4f-4f TRANSITION SPECTRA Nephelauxetic Effect Judd-Ofelt parameters Slator Condon Reaction Rate Thermodynamic
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Study on Uncertainties of Seismicity Parameters b and ν_4 in Seismic Statistical Zones
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作者 Pan Hua Li Jinchen Li Zhiguo 《Earthquake Research in China》 2007年第3期318-326,共9页
For several seismic statistical zones in North China, the key factors causing uncertainties in the important seismicity parameters b and v4 and the features of their uncertainties are discussed in this paper. The magn... For several seismic statistical zones in North China, the key factors causing uncertainties in the important seismicity parameters b and v4 and the features of their uncertainties are discussed in this paper. The magnitude of uncertainty is also analyzed. It can be seen that the key influencing factors are statistical period, methods of processing statistical samples, lower limit magnitude and the annual average occurrence ratio of large earthquakes. The variation ranges of b and v4 in the Tancheng-Lujiang zone are as high as 0.2 and 1. 4 respectively, which are similar to those in the Fenwei zone. They are much smaller however in the Hebei zone because of its sufficient statistical samples. 展开更多
关键词 Seismic statistical zone Seismicity parameters b value V4 Uncertainty
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胰腺癌中Fas、CCR4表达及与临床病理参数及预后的关系
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作者 韩万斌 鲁旭 《实用癌症杂志》 2024年第6期912-916,共5页
目的分析胰腺癌中Fas、趋化因子受体4(CCR4)的表达及与临床病理参数及预后的关系。方法收集手术治疗的118例胰腺癌患者癌组织标本及距离癌组织边缘4 cm以上的癌旁正常组织标本,采用免疫组织化学染色法检测118例癌组织及癌旁正常组织中Fa... 目的分析胰腺癌中Fas、趋化因子受体4(CCR4)的表达及与临床病理参数及预后的关系。方法收集手术治疗的118例胰腺癌患者癌组织标本及距离癌组织边缘4 cm以上的癌旁正常组织标本,采用免疫组织化学染色法检测118例癌组织及癌旁正常组织中Fas、CCR4表达情况,并分析Fas、CCR4表达与胰腺癌患者临床病理参数及预后的关系。结果胰腺癌癌组织中Fas阳性表达率显著低于癌旁正常组织(P<0.05),CCR4阳性表达率显著高于癌旁正常组织(P<0.05)。Fas表达与胰腺癌分化程度(P=0.005)、淋巴结转移(P=0.011)有关,与性别、年龄、肿瘤部位、肿瘤大小、TNM分期、血管侵犯无关(P均>0.05);CCR4表达与TNM分期(P=0.006)、淋巴结转移(P=0.027)有关,与性别、年龄、肿瘤部位、肿瘤大小、分化程度、血管侵犯无关(P均>0.05)。Fas阳性表达组总生存率显著高于Fas阴性表达组(P<0.05),CCR4阳性表达组总生存率显著低于CCR4阴性表达组(P<0.05)。淋巴结转移(P=0.013)、Fas表达(P=0.018)、CCR4表达(P=0.022)是影响胰腺癌患者预后的独立危险因素。结论Fas低表达及CCR4高表达可能与胰腺癌的发生发展有关,可用作评估胰腺癌预后的重要指标。 展开更多
关键词 胰腺癌 FAS 趋化因子受体4 病理参数 预后
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