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排序方式: 共有107条查询结果,搜索用时 562 毫秒
1.
铁在苹果树器官中的定量研究   总被引:1,自引:0,他引:1  
成龄苹果树整株分析结果表明 ,果实、叶片、枝干、根系的鲜重分别占整株鲜重的 42 .0 9%、6 .33%、38.81%、12 .77% ,以果实占鲜重的比例最大 ,单株鲜重为 2 0 7.90kg ;果实、叶片、枝干、根系的干重分别占整株干重的 19.5 1%、6 .45 %、5 7.30 %、16 .75 % ,以枝干占干重的比例最大 ,单株干重 84.37kg ,单株含水量 12 3.5 5kg。铁浓度以直径 <0 .5cm的根最高 ,达 2 5 7.5 1mg/kg ,其次为叶片 ,达 2 14.0 9mg/kg ,果实中铁浓度最低 ,为 18.2 7mg/kg;单株总铁含量 4915 .78mg,叶、果、根、枝干中铁含量分别为 116 4.6 5、30 0 .72、15 0 0 .30、1949.6 0mg ,分别占单株总铁量的2 3 .70 %、6 .12 %、30 .5 2 %和 39.6 6 %。  相似文献   
2.
To determine the role of the spleen in the pathogenesis of canine visceral leishmaniasis (CVL), we analyzed cellular immunophenotypic profiles of 52 dogs naturally infected with Leishmania infantum, clinically classified as follows: asymptomatic dogs-I (AD-I), seronegative/PCR+; asymptomatic dogs-II (AD-II), seropositive/PCR+; oligosymptomatic dogs (OD) and symptomatic dogs (SD). Seven non-infected dogs (CD) were included as a control group. AD-II presented higher levels of CD8+ T splenocytes and lower TCD4+/TCD8+ ratio in comparison with CD. OD and SD showed lower percentages of CD21+ as compared with AD-II. All seropositive dogs presented lower levels of CD45RA+ than CD. Regardless of the stimuli used, the proliferation index from splenocytes in vitro was inversely correlated with clinical status. After LSA stimulation, there was a higher percentage of specific CD8+ T in AD-II than CD and non-stimulated culture. In contrast, splenocytes from SD under in vitro LSA stimulation induced decreased MHC-II+ expression in comparison with all groups, and non-stimulated culture. In conclusion, the role of CD8+ T splenocytes seems to be important for an effective immunological response, a hallmark of asymptomatic CVL, whereas the pronounced loss of MHC-II expression upon LSA stimulation is a biomarker of symptomatic CVL.  相似文献   
3.
康平  汪秋宽 《水产科学》2006,25(3):155-157
皱纹盘鲍是我国北方海珍品的主要养殖种类,其特殊的生长习性、营养及药用价值说明它的消化能力强,体内具有活性强的酶。近年来,鲍内脏酶的研究越来越为人们所重视,特别是鲍内脏中的褐藻酸酶、纤维素酶、琼脂酶的研究和应用。本文主要研讨鲍内脏酶的组成、制备法及其应用前景。  相似文献   
4.
建立了番茄动态生长的功能模型,从个体和器官的角度,研究生物量在植物体内的生产和分配规律、器官的动态生长规则。模型根据蒸腾作用计算物质的生产;根据节间、叶柄、叶片和果实等器官的汇强和扩展规律对物质进行分配;根据与物质量的动态关系计算各器官的几何尺寸;利用试验数据对模型参数进行估计。通过对参数进行比较和分析得出它们对各器官生长的影响程度和器官本身的扩展规律。并对模型输出与测量数据的拟合程度进行了残差分析,验证了模型的合理性和有效性。  相似文献   
5.
除草剂阿特拉津影响大鼠脏器功能的毒理学研究   总被引:17,自引:0,他引:17  
试验研究了除草剂阿特拉津对大鼠脏器功能的影响。选用SD大鼠120只.雌雄各半,随机分成4组.分别按每千克体重200mg,100mg,10mg,0mg,设置高、中、低剂量3个处理组和1个对照组,药物配成乳浊液灌胃.并于喂药15d和30d采样测定甲状腺、胸腺、心脏、肺脏、肝脏、脾脏、肾脏、生殖腺等脏器与体重的相对比值。实验结果表明:阿特拉津对动物的代谢器官(肝脏、肾脏)具有损伤作用,使其发生退行性病变,中、高剂量组损伤作用尤为明显;阿特拉津使大鼠的免疫器官——胸腺、脾脏发生退行性病变,高剂量组损伤作用最为明显;雄性大鼠睾丸发生退行性病变,雌性大鼠卵巢则出现增生性病变,进而可能影响到大鼠的生殖功能。  相似文献   
6.
Cu在小麦不同部位的分配特征   总被引:1,自引:1,他引:1  
以郑州9023为材料,研究了小麦不同生育期植株不同部位Cu的含量、累积量以及不同生育阶段的吸 收量。结果表明,在整个生长过程中,小麦不同部位Cu的吸收、分配和累积随着时间的推移而不断变化,至灌 浆末期,各部位Cu含量从大到小依次为根>叶、废弃物、颖片>叶鞘>籽粒>茎、穗轴,地上各部位Cu累积量 从大到小依次为籽粒>茎、颖片>废弃物、叶鞘>叶>穗轴,因此,在小麦植株中较易富集Cu的部位是根、籽 粒和颖片;小麦在拔节-灌浆中期Cu吸收量及吸收速率明显高于其他时期。  相似文献   
7.
Computed tomography (CT) exams were conducted to determine the distribution of abdominal fat identified based on the CT number measured in Hounsfield Units (HU) and to measure the volume of the abdominal visceral and subcutaneous fat in minipigs. The relationship between the CT-based fat volumes of several vertebral levels and the entire abdomen and anthropometric data including the sagittal abdominal diameter and waist circumference were evaluated. Moreover, the total fat volumes at the T11, T13, L3, and L5 levels were compared with the total fat volume of the entire abdomen to define the landmark of abdominal fat distribution. Using a single-detector CT, six 6-month-old male minipigs were scanned under general anesthesia. Three radiologists then assessed the HU value of visceral and subcutaneous abdominal fat by drawing the region of interest manually at the T11, T13, L1, L3, and L5 levels. The CT number and abdominal fat determined in this way by the three radiologists was found to be correlated (intra-class coefficient = 0.9). The overall HU ranges for the visceral and subcutaneous fat depots were -147.47 to -83.46 and -131.62 to -90.97, respectively. The total fat volume of the entire abdomen was highly correlated with the volume of abdominal fat at the T13 level (r = 0.97, p < 0.0001). These findings demonstrate that the volume of abdominal adipose tissue measured at the T13 level using CT is a strong and reliable predictor of total abdominal adipose volume.  相似文献   
8.
Objective A dog model was developed to study visceral pain by stimulating the ovarian ligament. Study design Prospective experimental trial. Animals Twelve 1‐year old female hound dogs weighing 25.7 ± 3.6 kg. Methods Dogs were anesthetized with sevoflurane. The right ovary was accessed via laparoscopy. A suture was placed around the ovarian ligament and exteriorized through the abdominal wall for stimulation. The noxious stimulus consisted of pulling the ovary and ovarian ligament with a force transducer. The response to noxious stimulation was determined using the anesthetic minimum alveolar concentration requirement (MAC) for sevoflurane. The ovarian MAC was compared to the standardized somatic noxious stimulation tail clamp MAC. The results are depicted as mean ± SD and corrected to sea‐level. Results The stimulus–response curve during ovarian stimulation in three dogs was hyperbolic and best represented by a three‐parameter logistic growth curve model. The curve plateaued at 7.12 ± 4.19 N. From the stimulus‐response curve, we chose 6.61 N to test the consistency and repeatability of the model in nine dogs. The ovarian stimulation MAC for sevoflurane in these dogs was 2.16 ± 0.46%. The ovarian stimulation confidence interval and limits are comparable to the results from tail stimulation MAC. The tail stimulation MACs before and after laparoscopy surgery were not different (1.86 ± 0.28% and 1.77 ± 0.38% respectively; p > 0.05) but lower when compared to the ovarian MAC (p < 0.01). The dogs recovered from anesthesia without complications. Conclusions and clinical relevance The ovarian stimulation model is an adequate and repeatable means of producing visceral stimulation to determine MAC. The model may provide a humane mechanism to study the effectiveness of analgesics for acute ovarian pain.  相似文献   
9.
BDE209胁迫对翡翠贻贝(Perna viridis)SOD、MDA和GSH的影响   总被引:1,自引:0,他引:1  
采用半静态实验方法,研究不同浓度BDE209(0.1、1、10mg·L-1)在胁迫1、3、7、15d和清洁海水中释放3、7d后,翡翠贻贝(Perna viridis)外套膜和内脏团超氧化物歧化酶(Superoxide Dismutase,SOD)活性、丙二醛(Malondialdehyde,MDA)含量和谷胱甘肽(Glutathione,GSH)含量的变化规律。结果表明,BDE209胁迫后,翡翠贻贝2组织SOD活性先是受到明显的诱导作用,之后随胁迫时间延长被显著性抑制(P<0.01);BDE209对翡翠贻贝外套膜MDA含量的影响呈诱导-抑制反复变化,对内脏团MDA含量的影响表现为明显的诱导效应,其中胁迫第3d时的诱导率最高,为22.83%。翡翠贻贝外套膜GSH含量在BDE209胁迫初期就被显著诱导(P<0.01),随暴露时间延长诱导效应降低,在第15d时被显著性抑制(P<0.05);BDE209可诱导内脏团GSH含量显著性增加(P<0.05),但随暴露浓度增加GSH含量明显降低。清水恢复阶段,在清洁海水中恢复3d后,翡翠贻贝2组织MDA含量和GSH含量相对于对照组仍有显著性增加(P<0.05);而SOD活性总体在外套膜中受到抑制、内脏团中受到诱导,仅个别浓度组有所恢复。  相似文献   
10.
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