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冀北沙地人工林土壤逆转特征研究 被引量:3
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作者 马增旺 范少辉 +1 位作者 官凤英 邢存旺 《浙江林业科技》 北大核心 2013年第4期23-28,共6页
为了掌握零星沙地人工林营造后林地土壤的逆转变化特征,通过标准地调查,对榆树(Ulmus pumila)、侧柏(Platycladus orientalis)和小叶杨(Populus simonii)3个树种进行了调查。结果表明:人工固沙林不同程度地起到了拦截风沙、降低风蚀的作... 为了掌握零星沙地人工林营造后林地土壤的逆转变化特征,通过标准地调查,对榆树(Ulmus pumila)、侧柏(Platycladus orientalis)和小叶杨(Populus simonii)3个树种进行了调查。结果表明:人工固沙林不同程度地起到了拦截风沙、降低风蚀的作用,对改善输沙率以及土壤的机械组成、理化性质发挥了作用;不同林分的输沙率不同,但80%~90%的输沙集中发生在距离地面4 cm高度范围内,影响输沙量的主要林分结构因子是林分郁闭度,按输沙率大小排序9年生小叶杨林>7年生侧柏林>15年生小叶杨林>17年生侧柏林>7年生榆树林>=13年生榆树林;所有林地土壤的有机质、N素、P素仍然处于极低水平,呈极贫瘠状态,造林后地力的自然恢复进程非常缓慢。 展开更多
关键词 零星沙地 人工固沙林 输沙率 土壤理化性质 逆转特征
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Structural Characteristics and Molecular Mechanism of Hepatitis B Virus Reverse Transcriptase 被引量:6
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作者 Hui FENG Kang-hong HU 《Virologica Sinica》 SCIE CAS CSCD 2009年第6期509-517,共9页
Hepatitis B virus (HBV), a typical member of the Hepadnaviridae family, is responsible for infections that cause B-type hepatitis which leads to severe public health problems around the world. The small enveloped DNA-... Hepatitis B virus (HBV), a typical member of the Hepadnaviridae family, is responsible for infections that cause B-type hepatitis which leads to severe public health problems around the world. The small enveloped DNA-containing virus replicates via reverse transcription, and this unique process is accomplished by the virally encoded reverse transcriptase (RT). This multi-functional protein plays a vital role in the viral life cycle. Here, we provide a summary of current knowledge regarding the structural characteristics and molecular mechanisms of HBV RT. Improved understanding of these processes is of both theoretical and practical significance for fundamental studies of HBV and drug discovery. 展开更多
关键词 HEPADNAVIRUS Hepatitis B virus (HBV) Reverse transcriptase
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mRNA Expression of Chemokine Receptors on Peripheral Blood Mononuclear Cells and Correlation with Clinical Features in Systemic Lupus Erythematosus Patients 被引量:2
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作者 Yu-mei Li Zhi-qiang Chen +4 位作者 Xu Yao Ai-zhen Yang An-sheng Li Dong-ming Liu Juan-qin Gong 《Chinese Medical Sciences Journal》 CAS CSCD 2010年第3期162-168,共7页
Objective To investigate the expressions of chemokine receptors and interleukin (IL) receptors on the peripheral blood mononuclear cells (PBMCs) from systemic lupus erythematosus (SLE) patients and their correla... Objective To investigate the expressions of chemokine receptors and interleukin (IL) receptors on the peripheral blood mononuclear cells (PBMCs) from systemic lupus erythematosus (SLE) patients and their correlations with clinical features as well as SLE disease activity index (SLEDAI). Methods The mRNA expressions of chemokine receptors and IL receptors on PBMCs of 93 SLE patients and 30 healthy controls were detected by reverse transcription-polymerase chain reaction, including CCR2, CCR3, CCR4, CCR5, CCR6, CCR8, CXCR3, CXCR5, CX3CR1, XCR1, IL-4R, and IL-10R. The clinical features of SLE patients were recorded. The correlations of chemokine receptors and IL receptors mRNA expressions with clinical features as well as SLEDAI were assayed using linear regression analysis. Results The level of CCR5 mRNA in SLE patients (including active and inactive SLE) was signifi- cantly higher than that in healthy controls (P〈0.05), and there was no significant difference between active and inactive patients in this respect (P〉0.05). CX3CR1 mRNA expression significantly increased from healthy control to inactive SLE to active SLE in sequence. The others (except for CCR8, CXCR3, and IL-1 OR) in active SLE patients weresignificantly higher than those in both inactive SLE patients and healthy controls (all P〈0.05). There were positive correlations between SLEDAI and CCR2 (r=0.424, t=4.313, P〈0.001), CCR3 (r=0.518, t=5.410, P〈0.001), CCR4 (r=0.376, t=3.851, P〈0.001), CCR6 (r=0.457, t=4.513,P〈0.001), CXCR5 (r=0.455, t=4.629, P〈0.001), CX3CR1 (r=0.44-5, t=4.523, P〈0.001), as well as XCRI (r=0.540, t=5.445, P〈0.001). And CCR5 mRNA expression level was positively correlated with IL-4R mRNA (r=0.313, t=2.353, P〈0.05). The patients with myositis and cutaneous vasculitis simultaneously showed lower levels of CCR5 and CX3CRI, and CCR5 expression was negatively correlated with the scores of SLEDAI in SLE cases accompanied by photosensitivity (r=0.426, t=- 2.155, P〈0.05). Conclusion Increased expressions of CCR5 and CX3CRI on PBMCs may be indicators in clinical survey for SLE. 展开更多
关键词 systemic lupus erythematosus chemokine receptors peripheral bloodmononuclear cell
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