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1.
Nobuhiko Ohga 《Ecological Research》1992,7(3):341-353
Herbaceous lomas in the Peruvian coastal desert, of South America establish in spring, and its habitat is limited to the southern
or southwestern slopes along the coast that are affected by thick fog. The time of appearance, the duration and the thickness
of the fog vary greatly from year to year, so the lomas can grow only in habitats with enough water to, sustain seed germination
and plant growth. This paper studies the species composition and density of the buried seed population, of the herbaceous
lomas of Loma Ancon in order to clarify the mechanisms of the lomas' establishment. The mean number of species with viable
seeds was about, 12 spp. m−2 and that of dead seeds was about 22 spp. m−2. The dominant species wereSolanum tuberiferum, S. pinnatifidum andNolana humifusa, both in viable and dead seeds. Viable seed density was about 5000–8000 seeds m−2, which is comparable with the seed densities of other herbaceous communities. Dead seed density was about 15000–27000 seeds
m−2, or nearly three times the viable seed density, because the rate of decomposition was slow in the extremely dry conditions.
The net increase of viable seeds by seed production was estimated at about 5000 seeds m−2 in 1980, and the increase in the number of dead seeds was 2200 seeds m−2. 相似文献
2.
Use of ATP to characterize biomass viability in freely suspended and immobilized cell bioreactors 总被引:2,自引:0,他引:2
This work describes investigations into the viability of cells growing on 3,4-dichloroaniline (34DCA). Two bioreactors are employed for microbial growth, a continuous stirred tank (CST) bioreactor with a 2-L working volume, and a three-phase air lift (TPAL) bioreactor with a 3-L working volume. Experiments have been performed at several dilution rates between 0.027 and 0.115 h(-1) in the CST bioreactor and between 0.111 and 0.500 h(-1) in the TPAL bioreactor. The specific ATP concentration was calculated at each dilution rate in the suspended biomass in both bioreactors as well as in the immobilized biomass in the TPAL bioreactor. The ATP was extracted from the cells using boiling tris-EDTA buffer (pH 7.75), and the quantity determined using a firefly (bioluminescence) technique. The cultures were inspected under an electron microscope to monitor compositional changes. Results from the CST bioreactor showed that the biomass-specific ATP concentration increases from 0.44 to 1.86 mg ATP g(-1) dry weight (dw) as dilution rate increases from 0.027 to 0.115 h(-1). At this upper dilution rate the cells were washed out. The specific ATP concentration reached a limiting average value of 1.73 mg ATP g(-1) dw, which is assumed to be the quantity of ATP in 100% viable biomass. In the TPAL bioreactor, the ATP level increased with dilution rate in both the immobilized and suspended biomass. The specific ATP concentration in the immobilized biomass increased from approximately 0.051 mg ATP g(-1) dw at dilution rates between 0.111 and 0.200 h(-1) to approximately 0.119 mg ATP g(-1) dw at dilution rates between 0.300 and 0.500 h(-1). This indicates that the immobilized biomass contained a viable cell fraction of around 5%. Based on these results, kinetic data for freely suspended cells should not be applied to the modeling of immobilized cell systems on the assumption that immobilized biomass is 100% viable. (c) 1993 John Wiley & Sons, Inc. 相似文献
3.
A dynamic treatment regime (DTR) is a sequence of decision rules that provide guidance on how to treat individuals based on their static and time-varying status. Existing observational data are often used to generate hypotheses about effective DTRs. A common challenge with observational data, however, is the need for analysts to consider “restrictions” on the treatment sequences. Such restrictions may be necessary for settings where (1) one or more treatment sequences that were offered to individuals when the data were collected are no longer considered viable in practice, (2) specific treatment sequences are no longer available, or (3) the scientific focus of the analysis concerns a specific type of treatment sequences (eg, “stepped-up” treatments). To address this challenge, we propose a restricted tree–based reinforcement learning (RT-RL) method that searches for an interpretable DTR with the maximum expected outcome, given a (set of) user-specified restriction(s), which specifies treatment options (at each stage) that ought not to be considered as part of the estimated tree-based DTR. In simulations, we evaluate the performance of RT-RL versus the standard approach of ignoring the partial data for individuals not following the (set of) restriction(s). The method is illustrated using an observational data set to estimate a two-stage stepped-up DTR for guiding the level of care placement for adolescents with substance use disorder. 相似文献
4.
Molecular genetic and phenotypic alteration of Escherichia coli in natural water microcosms containing toxic chemicals 总被引:2,自引:0,他引:2
Abstract Microcosms of sterile Chesapeake Bay water were used to study effects of sub-lethal concentrations (1 μl/l) of nitrobenzene, m -cresol, and dibutyl phthalate on Escherichia coli H10407. E. coli remained viable during the 19-day test period in estuarine water, both in the presence and absence of the chemicals, long after it became non-culturable. Analysis of membrane proteins revealed changes in the protein composition. Carbohydrate and amino acid utilization was affected by these changes. Plasmids in E. coli H10407 could not be detected following microcosm exposure. When the cells were transferred to rich medium without toxic chemicals, growth resumed and plasmid bands were again detectable. 相似文献
5.
本文介绍了加速贮存实验预测冻干活菌制品存活期的方法,并用此法对冻干青春型双歧杆菌DM8504的存活期进行了预测。结果表明,预测结果与实验测试结果非常接近,两者没有显著性统计学差异,笔者认为加速贮存实验法是预测冻干活菌稳定性的一种快速而可行的方法。 相似文献
6.
目的探讨双歧三联活菌胶囊对急性胰腺炎患者肠黏膜屏障功能的保护作用。方法选取急性胰腺炎患者66例,随机分为观察组和对照组。两组患者均予以禁食水、持续胃肠减压、解痉镇痛、抗感染、抑制胃酸分泌、生长抑素、改善局部微循环和保持水电解质酸碱平衡等常规治疗。观察组患者加用双歧杆菌三联活菌胶囊420mg水化后自胃管灌注,夹管1.5h,3次/d,连用7d。观察两组患者的治疗前后肠黏膜屏障功能的变化情况,并比较其临床疗效。结果治疗7d后,两组患者血清内毒素、TNF—α和D-乳酸水平均有明显下降(P〈0.05或P〈0.01),且观察组下降值比对照组更明显(P〈0.05);同时观察组患者临床总有效率为93.94%,明显高于对照组的75.76%(χ2=4.24,P〈0.05)。结论双歧杆菌三联活菌胶囊治疗急性胰腺炎效果较好,能降低血清内毒素、TNF-α和D-乳酸水平,对患者肠黏膜屏障功能具有良好的保护作用。 相似文献
7.
摘要 目的:观察醒脾养儿颗粒联合双歧杆菌三联活菌散对轮状病毒腹泻患儿免疫功能、心肌酶指标和血清白介素 -6(IL-6)、C反应蛋白(CRP)的影响。方法:选取 2018年 1月到 2021年 1月期间我院接收的 92例轮状病毒腹泻患儿。根据随机数字表法将患儿分为对照组和研究组,各为 46例。对照组患儿接受双歧杆菌三联活菌散治疗,研究组患儿接受醒脾养儿颗粒联合双歧杆菌三联活菌散治疗,均治疗 3 d。观察两组疗效,记录不良反应发生情况。观察并对比两组患儿免疫功能[免疫球蛋白(Ig)M、IgG和 IgA]、心肌酶指标[磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)、肌酸激酶同工酶(CK-MB)]和血清 IL-6、CRP的变化情况。结果:研究组的临床总有效率为 91.30%(42/46),高于对照组患者的 71.74%(33/46),差异有统计学意义(P<0.05)。两组治疗 3 d后血清 IgM、IgG、IgA水平较治疗前升高,且研究组的改善程度优于对照组(P<0.05)。两组治疗 3 d后血清 LDH、CK、CK-MB水平较治疗前降低,且研究组的改善程度优于对照组(P<0.05)。两组治疗 3 d后血清 IL-6、CRP水平较治疗前降低,且研究组的改善程度优于对照组(P<0.05)。两组患儿均未见明显不良反应发生。结论:醒脾养儿颗粒联合双歧杆菌三联活菌散治疗轮状病毒腹泻患儿,可提高免疫力,减轻心肌损伤,降低血清 IL-6、CRP水平,安全有效。 相似文献
8.
目的探究双歧杆菌三联活菌胶囊辅助治疗术后早期炎性肠梗阻的临床效果。方法收集兰州大学第一医院2014年9月至2016年9月收治的术后早期炎性肠梗阻患者56例为研究对象,随机分为对照组和干预组,每组28例,对照组予以常规治疗,干预组在对照组治疗基础上加用双歧杆菌三联活菌胶囊。收集整理两组患者临床数据并分析比较临床治疗效果。结果两组患者治疗总有效率差异无统计学意义(P0.05)。干预组患者腹胀消失时间、肛门排气时间、肠鸣音恢复时间均较对照组短(P0.05);两组患者治疗前后降钙素原下降及淋巴细胞绝对值增加差异均有统计学意义(P0.05),且干预组治疗前后降钙素原降低及淋巴细胞绝对值增加幅度与对照组相比差异均有统计学意义(P0.05)。结论双歧杆菌三联活菌胶囊用于术后早期炎性肠梗阻的治疗,可缩短治疗时间,促进肠道免疫功能恢复,且使用安全,值得临床推广。 相似文献
9.
目的 探讨双歧杆菌三联活菌胶囊辅助治疗对新诊断2型糖尿病(T2DM)患者β细胞功能及胰岛素抵抗的影响。方法 选取128例新诊断T2DM患者,随机分为研究组和对照组。两组患者均按照相同要求进行饮食控制和运动干预。对照组患者予以阿卡波糖联合甘精胰岛素控制血糖治疗;研究组患者在对照组治疗基础上加用双歧杆菌三联活菌胶囊420 mg/次,3次/d,温水口服,两组患者均连用12周。观察并比较两组患者治疗前和治疗12周后糖代谢指标、β细胞功能及胰岛素抵抗的变化。结果 治疗12周后,两组患者空腹血糖(FBG)、餐后2 h血糖(2 hPG)和糖化血红蛋白(HbA1C)较前明显下降(P<0.05或P<0.01),且研究组下降值较对照组更明显(P<0.05);同时两组患者HOMA-β较前明显上升,HOMA-IR较前明显下降,且研究组上升或下降值较对照组更明显(P<0.05)。结论 双歧杆菌三联活菌胶囊辅助治疗新诊断T2DM患者可改善其β细胞功能,缓解胰岛素抵抗,提高胰岛素敏感性,从而改善糖代谢功能,有利于血糖稳定,使糖化血红蛋白达标。 相似文献
10.
采用meta分析评价双歧杆菌三联活菌散/胶囊治疗儿童呼吸道感染继发腹泻的临床疗效。
计算机检索中国知网、维普、万方、PubMed、Web of Science和Embase数据库,收集全球范围内在治疗儿童呼吸道感染继发腹泻中使用双歧杆菌三联活菌制剂(散/胶囊)的随机对照研究和前瞻性非随机对照研究,检索时间截至2022年7月,采用Jadad评分量表对纳入文献进行质量评价,采用Cochrane协作网提供的RevMan 5.4分析软件进行数据处理和meta分析。
纳入19篇公开发表的文献进行meta分析,共3 086例患者,治疗组(对照组常规治疗措施+双歧杆菌三联活菌散/胶囊)1 578例,对照组1 508例,meta分析结果显示,治疗组的总体有效率显著高于对照组[
双歧杆菌三联活菌散/胶囊与常规治疗方法相比,可以提高儿童呼吸道感染继发腹泻的治疗总体有效率、治疗显效率,同时有效降低患儿的腹泻发病率。