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991.
稻飞虱是缅甸水稻种植区常见且分布广泛的一类害虫,可造成农作物不同程度的减产.稻飞虱的爆发与高产品种的大规模推广种植具有一致性,同时其种群变化也与天气条件有关.近年来,缅甸中部部分省份稻飞虱大量孳生,在一定程度上,这与氮肥施用水平有关.雨季稻飞虱种群增加,7月和8月为高峰期.在缅甸,主要通过培育抗虫、抗旱、抗逆等水稻品种来防控稻飞虱.同时用诱虫灯进行早期入侵的虫源的监测,必要时,采用化学杀虫剂防治.缅甸部分农场还采用了病虫害综合管理系统(IPM),以建立健康、安全、可调节的水稻生态系统及可持续的病虫害管理. 相似文献
992.
血栓通注射液(冻干)(XST)是一种从三七中提取的中草药标准化产品,广泛用于临床治疗急性脑梗塞等脑血管疾病。本研究评估了XST在不同大鼠脑缺血模型中的急性和延长保护作用,并探讨了其对过氧化物酶(Prx) 6-toll样受体(TLR) 4信号通路的影响。用XST处理抑制过氧化物酶(Prx) 6-toll样受体(TLR) 4的蛋白质表达和p38的磷酸化水平,并且上调STAT3的磷酸化水平。XST治疗3 d可显著降低暂时性大脑中动脉阻塞(MCAO)诱导的梗死体积和肿胀百分比,并调节白细胞介素-1β(IL-1β)、IL-17、IL-23p19、肿瘤坏死因子-α(TNFα)和诱导型一氧化氮合酶(iNOS)。在永久MCAO大鼠中,XST可以减少梗死体积和肿胀百分比。XST治疗还可以增加大鼠的体重并改善一批功能结果。XST可以保护暂时性和永久性MCAO大鼠的缺血性损伤可能与Prx6-TLR4途径有关。 相似文献
993.
Abstract. The nurse-plant syndrome is a widely recognized example of positive (facilitative) influences of plant species on the establishment and growth of other species. Most studies of the nurse-plant syndrome have been on species that reproduce mainly from seed rather than vegetatively. In this study, we experimentally compared the influences of two species of nurse shrubs, Schinus patagonicus and Berberis buxifolia, on the survival and growth of vegetatively reproducing herbaceous and woody plants in a post-fire shrubland in northern Patagonia, Argentina. The vegetation beneath shrubs was removed by clipping and, in a paired-sample design, one half of the canopy of each shrub was removed. We determined species richness, counted number of resprouts, and measured photon flux density and soil moisture beneath cut and uncut halves of each shrubs. Abundances of resprouts were several times greater beneath the uncut vs. the cut shrubs, as was the mean number of species. Thus, shrubs have a strong facilitating influence as measured by resprout densities and the number of species. Numbers of resprouts and of species were twice as high beneath Schinus as beneath Berberis, implying important differences in the facilitative effects of the two shrubs species. Microsites beneath Schinus were characterized by lower and more heterogeneous light levels but by greater soil moisture. Even though the reproductive mode in this post-fire shrubland is overwhelmingly vegetative, facilitation by nurse shrubs is important and differentially effective for different species of nurse shrubs. 相似文献
994.
995.
Coral communities were investigated in the northwestern Gulf of Aden, Yemen, for their composition, structure, and bioconstruction potential. Although no true reef was encountered, high cover coral carpets were found where hard substrate was available. Seven different types of coral communities were differentiated, and both non-framework and framework coral communities were found. Monotypy or oligotypy seem to be consistent characteristics of framework-building coral communities in the study area. Apart from substrate availability, proximity to the upwelling area and exposure were found to be the most important environmental factors influencing coral communities structure, composition, and bioconstruction potential. 相似文献
996.
Anatomically intact articular cartilage in form of sesamoid bones from metacarpophalangeal joints of 2-year-old cows was tested for its influence on the microbicidal effect of the iodophore Betaisodona, the bispyridinamine Octenisept, and the biguanide Lavasept. Comparisons were carried out in Ham's F12 medium with and without 0.2% bovine serum albumin as organic matter loading. The expected abolition of the microbicidal effect of these antiseptics against the test organisms Escherichia coli or Staphylococcus aureus in the presence of sesamoid bone was not evident. Furthermore, sesamoid bone alone demonstrated antibacterial activity against Staphylococcus aureus, which may involve adherence of bacteria to surface constituents of articular cartilage. Final concentrations of 2.5-5% Betaisodona, 5% Octenisept as well as 0.025% Lavasept are effective in killing of 10(8)-10(9) cfu/ml Escherichia coli or Staphylococcus aureus in the presence of sesamoid bone without the reduction of antimicrobial activity expected from binding to CS, which has previously been demonstrated for CS in solution. 相似文献
997.
Hinderaker MP Raines RT 《Protein science : a publication of the Protein Society》2003,12(6):1188-1194
The well-known preference of the peptide bond for the trans conformation has been attributed to steric effects. Here, we show that a proline residue with an N-formyl group (H(i-1)-C'(i-1)=O(i-1)), in which H(i-1) presents less steric hindrance than does O(i-1), likewise prefers a trans conformation. Thus, the preference of the peptide bond for the trans conformation cannot be explained by steric effects alone. Rather, an n --> pi* interaction between the oxygen of the peptide bond (O(i-1)), and the subsequent carbonyl carbon in the polypeptide chain (C'(i)) also contributes to this preference. The O(i-1) and C'(i) distance and O(i-1).C'(i)=O(i) angle are especially favorable for such an n --> pi* interaction in a polyproline II helix. We propose that this electronic effect provides substantial stabilization to this and other elements of protein structure. 相似文献
998.
??????? 目的 基于失效模式与效应分析(FMEA)方法分析控制C形臂X线机的使用风险。方法 成立FMEA 5人小组,运用现场观察和访谈的方法,识别C形臂X线机使用的潜在失效模式,并对其发生的严重度、发生概率及检测的难易度进行评价打分,计算失效原因的风险优先指数。结果 FMEA小组找出了必须优先解决的C臂机使用的失效模式,制定并实施了改进措施,在不增加管理成本的基础上,取得了良好的管理效果。结论 FMEA可以评估医疗设备使用过程的失效,并能排序优先解决的问题,不增加管理成本就能预防问题的发生,是有效的过程管理工具。 相似文献
999.
Non-crop vegetation of field margins provides resources for natural enemies of crop herbivores. However, it is still not well known whether this resource provisioning effect is strong enough to improve herbivore regulation within crop fields and which plant species and functional groups favour this ecosystem service. A better understanding of the interactions between field margin vegetation and herbivore regulation is crucial to evaluate management strategies and to design suppressive plant mixtures. We surveyed 64 wheat and oilseed rape fields of Western France for two years (16 fields per year and crop) in order (1) to identify plant diversity or group effects on herbivore regulation within crop fields and (2) to identify species within plant groups that improve regulation. Herbivores, herbivore damage and natural enemies were monitored on crop plants at a distance of 5 and 50 m from the field margin. At the same time, the cover and phenological stage of all vascular plants were estimated in the adjacent field margin. The study demonstrated a positive relationship between the cover of entomophilous plant species that were flowering at the survey date and response variables related to herbivore regulation. Plant species richness and the cover of plant species taxonomically close to crop plants had a small influence on herbivores and natural enemies in wheat whereas related wild Brassicaceae increased herbivory and decreased herbivore regulation in oilseed rape. Within the entomophilous flowering plants, several species were significantly related to a better herbivore regulation in univariate analyses. Multivariate ordination techniques allowed the identification of plant species influencing several response variables of herbivore regulation at the same time. Our study demonstrated the importance of entomophilous species that flowered at peak infestation of crop herbivores. Spontaneous field margins rich in flowering entomophilous species provide an important ecosystem service without expensive sowing of seed mixtures. 相似文献
1000.
摘要 目的:探讨胶原生物膜在耳内镜下乳突根治术中的应用效果。方法:选取徐州医科大学附属医院2021年4月至2022年 2月收治的51例中耳胆脂瘤患者进行回顾性分析,其中研究组27例患者予以胶原生物膜修复皮肤缺损,对照组予以颞肌筋膜修复术腔皮肤缺损,观察两组患者术后临床症状,手术时长,术腔完全上皮化时间、干耳时间及术前术后听力改变。结果:研究组术后患者因外耳道进水,存在感染及肉芽生长者1例,予以清理后未再次生长;对照组术后发生1例外耳道口狭窄的情况,予以橡胶扩张管进行扩张并后并定期清理术腔肉芽、脱落痂皮,患者外耳道恢复良好。两组术前耳闷、耳痛、耳鸣及术后耳痛VAS评分无明显差异(P>0.05);研究组术后耳闷及耳鸣VAS评分较对照组降低(P<0.05)。研究组平均手术时长、术后术腔完全上皮化时间及平均干耳时间短于对照组(P<0.05)。两组术前术后气骨导差(ABG)、平均气导听阈(AC)比较差异均无统计学意义(P>0.05)。结论:作为术区移植物,胶原生物膜应用于耳内镜下中耳胆脂瘤乳突根治术可加快创面术腔的修复,减少局部创伤与操作步骤,改善临床症状,缩短手术时间、术后术腔完全上皮化时间及获得干耳时间,可作为临床上有效的修复材料。 相似文献