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991.
水资源短缺是影响黄土高原雨养农业发展的关键性因素,雨水资源开发是缓解该地区水资源短缺的有效措施.本研究利用管式 TDR 系统监测21年红富士老果园0~300 cm土层土壤含水率变化,分析了雨水集聚深层入渗(RWCI)系统下黄土高原旱作山地果园土壤水分时空分布特征.结果表明: RWCI系统能够显著增加果园土壤含水率,特别是40~80 cm土层(土壤含水率低值区)土壤含水率,在该区域,不同设计深度(40、60和80 cm)RWCI处理(RWCI40、RWCI60和RWCI80)年均土壤含水率分别较鱼鳞坑(CK)处理提高75.3%、85.4%和62.4%,分别较裸露坡地(BS)处理提高39.2%、47.2%和29.1%.RWCI40、RWCI60和RWCI80处理土壤水分入渗最大深度分别为80、120和180 cm,显著深于CK处理(60 cm),其中土壤水分变化幅度最大的土层分别主要发生在0~60、0~100和0~120 cm.在果树整个生育期内,RWCI处理土壤平均含水率(0~300 cm)以RWCI80处理最大,其次是RWCI40和RWCI60处理.总体来看,RWCI系统是黄土高原实现雨水资源化和农业高效用水的有效措施.  相似文献   
992.
组织型纤维原激活剂(tPA)的作用是激活血纤维蛋白酶原,从而溶解血栓。生物体内tPA的含量很低,远远不能满足临床需要。为了利用转基因动物生产tPA,需要对所用tPA乳腺表达载体pSVL-WAP-tPA2(Fig.1)进行予证。将三种待研究载体分别用脂质体包埋,注入中后期怀孕母兔乳腺。对乳汁、乳腺组织的mRNA和DNA分别进行检测。实验兔分娩后,每4天取乳汁冻存,ELISA检测其中tPA含量(Fig.2),泌乳期第4天最高可达600ng/ml。又,于乳腺注射第3天,手术切取部分乳腺组织,制备总RNA,以β-Casein启动子下游序列(TACTAG…)为引物Ⅰ,tPA上游序列(TTCCCA…)为引物Ⅱ,做RT-PCR检测,表明:此时已有tPAmRNA转录(Fig.3)。再,于停乳后30天左右,切取部分乳腺制备DNA,以tPAcDNA为探针,做Southern杂交检测,表明:无tPA整合,仅是以附合体形式存在(Fig.4)。上述质粒直接注射技术是予证转基因用载体表达水平的快捷、简便方法。  相似文献   
993.
中国红螯蛛属两新种及两种雄蛛新发现(蜘蛛目:管巢蛛科)   总被引:1,自引:0,他引:1  
本文记述红螯蛛属2新种,即宁明红螯蛛Cheiracanthiumningmingensis,sp.nov,和思茅红螯蛛Cheiracanthiumsimaoensis,sp.nov及2种雄性的补充描述,即粗美红螯蛛CheiracanthiumexquestiumZhangetZhu,1993和纤红螯蛛CheiracanthiumfibrosumZhangetal,1994模式标本保存于湖南省生物研  相似文献   
994.

Background

The purpose of this case series is to investigate the relationship between splenic thickness (ST) and postoperative outcomes after hepatic resection in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) patients.

Methods

The clinical data of 320 patients with HBV-associated HCC who had undergone liver resection were retrospectively analyzed. The value of ST in predicting postoperative outcomes was evaluated.

Results

A total of 320 patients were enrolled in the study. An increase in ST was significantly associated with an increase in portal vein diameter (PVD), indocyanine green retention rate 15 min (ICG R15), and total bilirubin (TBIL); however, it was negatively correlated with platelet count (PLT). Post-hepatectomy liver failure (PHLF) occurred in 35 (10.9%) patients. Multivariate logistic regression analysis showed that ST was an independent predictor of morbidity and mortality after hepatectomy. Meanwhile, ST was associated with an almost sixfold increased risk for developing perioperative complications (OR 5.678; 95% CI 2.873 to 11.224; P?<?0.001) and almost 13-fold increased risk for mortality after hepatectomy (OR 13.007; 95% CI 1.238 to 136.627; P?=?0.033).The area under the receiver operating characteristic (ROC) curve (AUC) of ST for predicting the incidence of PHLF was 0.754 (95% confidence interval (CI) 0.667 to 0.841; P?<?0.001), with a sensitivity of 57.1% and a specificity of 82.5%, which were significantly greater than those of the ICG R15 level (AUC 0.670; 95% CI 0.560 to 0.779; P?<?0.001). The critical value of ST was 43.5 mm.

Conclusions

ST, which is an easy, inexpensive, and routinely available perioperative marker, showed a favorable predictive value for postoperative outcomes in HBV-associated HCC patients.
  相似文献   
995.
996.
Sex‐determination mechanisms vary both within and among populations of common frogs, opening opportunities to investigate the molecular pathways and ultimate causes shaping their evolution. We investigated the association between sex‐chromosome differentiation (as assayed from microsatellites) and polymorphism at the candidate sex‐determining gene Dmrt1 in two Alpine populations. Both populations harboured a diversity of X‐linked and Y‐linked Dmrt1 haplotypes. Some males had fixed male‐specific alleles at all markers (“differentiated” Y chromosomes), others only at Dmrt1 (“proto‐” Y chromosomes), while still others were genetically indistinguishable from females (undifferentiated X chromosomes). Besides these XX males, we also found rare XY females. The several Dmrt1 Y haplotypes differed in the probability of association with a differentiated Y chromosome, which we interpret as a result of differences in the masculinizing effects of alleles at the sex‐determining locus. From our results, the polymorphism in sex‐chromosome differentiation and its association with Dmrt1, previously inferred from Swedish populations, are not just idiosyncratic features of peripheral populations, but also characterize highly diverged populations in the central range. This implies that an apparently unstable pattern has been maintained over long evolutionary times.  相似文献   
997.
The new teleost fish PKZ (PKR-like) full-length cDNA (GU299765) had been cloned and identified from grass carp (Ctenopharyngodon idellus). The cDNA of grass carp PKZ (CiPKZ) has 2185 bp in length with a largest open reading frame (ORF) encoding 513aa. CiPKZ possesses a conserved C-terminal catalytic domain of eIF2α kinase family. Within its N-terminal there are two binding domain (Zα) named Zα1 (1-67aa) and Zα2 (81-152aa). BLAST homologous search reveals that CiPKZ has a high-level homology with other fish PKZs and PKRs. Like other fish PKZs and PKRs, CiPKZ is a ubiquitous tissue expression gene that had a very low level of constitutive expression but up-regulated in response to Poly I:C or hot stress (34 °C). For the purpose of searching for the potential function of CiPKZ, we obtained CiPKZ polypeptide via Escherichia coli Rosetta prokaryotic expression and purified with Ni-NTA His-Bind Resin affinity chromatography. CiPKZ polypeptide was used for the test of phosphorylating eIF2αin vitro. The results demonstrated that CiPKZ could be activated by Z-DNA but not by Poly I:C, and with subsequent could phosphorylate eIF2α. Meanwhile, four pcDNA3.1/PKZ recombinant plasmids, including pcDNA3.1/PKZ-wet, pcDNA3.1/PKZ-wet-K198R, pcDNA3.1/PKZ-wet-C, pcDNA3.1/PKZ-wet-C-K198R had been constructed, respectively. Mouse Myeloma cells (Sp2/0) and Human Umbilical Vein Endothelial Cells (HUVEC) were transiently cotransfected with pcDNA3.1/PKZ recombinant plasmid and PGL-3-promoter plasmid. The results revealed that CiPKZ could greatly decrease luciferase level in these cells. Zα and the K198 amino acid residue may play a key role in its function.  相似文献   
998.
Wei W  Xu Z  Shi SL  Tian QS  Wang HP  Liu JL 《应用生态学报》2011,22(10):2686-2692
运用参与式方法调查了内蒙古农牧交错区太仆寺旗不同类型农牧户的生计现状,分析了不同类型农牧户的生计策略、制约因素和提高途径.结果表明:纯农型家庭规模小,年龄结构偏大,整体文化水平低,生计策略单一,脆弱性和风险较大,引入非农生产活动是降低生计风险和提高生活水平的重要途径;纯牧型家庭以放牧为主要谋生方式,草场脆弱性对其生产活动影响很大,发展环境友好型高产农牧业是解决生计问题和环境问题的有效途径;农业兼业型和牧业兼业型家庭规模大,年龄结构轻,劳动力分工多样化,从事非农活动的比例较大,生活水平较好,尤以牧业兼业型家庭收入更高.  相似文献   
999.
Arsenite has a long history in treating leukemia, which might be also effective in the therapy of other cancers. Our previous published data have demonstrated that arsenite exposure induces apoptosis in the HepG2 human hepatoma cells via activating JNKs/AP-1 pathway, but the upstream signaling events responsible for JNKs (c-Jun N-terminal kinase) cascade activation have not been fully discovered. Since cross-talk between IKK/NF-κB and JNKs pathways under stress conditions is a hot topic, in this article, we investigate the potential roles of IKKα and IKKβ, the catalytic subunits of IKK complexes, in the arsenite-induced JNKs pathway activation in the HepG2 cells. We found that arsenite exposure induced JNKs and AP-1 activation accompanying with a significant reduction of both IKKα and IKKβ expressions. Overexpression of IKKβ, but not of IKKα, inhibited arsenite-induced MKK7/JNKs/AP-1 pathway activation as well as the apoptotic response. Therefore, we conclude that the downregulation of IKKβ expression is the prerequisite signaling event for mediating JNKs pathway activation and the cellular apoptotic response in the HepG2 cells under arsenite exposure. Targeting IKKβ might be helpful to enhance the tumor therapeutic effect of arsenite.  相似文献   
1000.
Most Drosophila species sing species-specific pulse songs during their "precopulatory courtship." Three sibling species of the Drosophila montium species subgroup performed "copulatory courtship": males generated courtship songs by vibrating either wing only after mounting and during copulation. In these three species, strong sexual isolation was detected between D. ohnishii and D. lini and between D. ohnishii and D. ogumai, but not between D. lini and D. ogumai. Female showed strong repelling behavior when they were mounted by a heterospecific male in the species combinations including D. ohnishii, resulting in failure of the copulation attempt of the male. Acoustic analyses of courtship songs revealed that the pulse song was irregular, without any species-specific parameters, but that the frequency of the sine song was different among the three species in accordance with the modes of sexual isolation between them; it was significantly lower in D. ohnishii (mean ± SE = 193.0 ± 1.7 Hz) but higher in D. lini (253.4 ± 2.7 Hz) and D. ogumai (246.7 ± 5.3 Hz). We suggest that this difference in the sine song frequency is a sexual signal in the Specific Mate Recognition System (SMRS) among these three Drosophila species.  相似文献   
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