首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
目的观察EB病毒(EBV)与人类巨细胞病毒(HCMV)感染所致的传染性单核细胞增多症(IM)患儿超敏C-反应蛋白(hs-CRP)、白细胞(WBC)计数、嗜中性粒细胞比值(N)、异常淋巴细胞(异淋)、嗜异性抗体和血清酶的变化。方法选择70例确诊有EBV病毒感染且具备传染性单核细胞增多症临床特点的患儿(A组)进行实验室检测指标分析及总结;并与37例HCMV相关传染性单核细胞增多症患儿(B组)进行比较。结果与EB组(A组)比较,HCMV组(B组)感染患儿hs-CRP水平、肌酸激酶同功酶(CK-MB)、丙氨酸氨基转移酶(ALT)、外周血WBC计数、异型淋巴细胞增高程度较低(P〈0.05),嗜异性抗体常为阴性,两组N值差异无统计学意义(P〉0.05)。结论 EBV与HCMV感染所致的传染性单核细胞增多症患儿的实验室指标变化不同,应重视IM患儿的实验室检查以辅助诊断。  相似文献   

2.
The ability of carbon nanotubes (CNTs) to undergo surface modification allows them to form nanocomposites (NCs) with materials such as polymers, metal nanoparticles, biomolecules, and metal oxides. The biocidal nature, protein fouling resistance, and fouling release properties of CNT-NCs render them the perfect material for biofouling prevention. At the same time, the cytotoxicity of CNT-NCs can be reduced before applying them as substrates to promote biofilm formation in environmental biotechnology applications. This paper reviews the potential prospects of CNT-NCs to accomplish two widely varying objectives in environmental engineering applications: (i) preventing biofouling, and (ii) promoting the formation of desirable biofilms on materials surface. This paper addresses practical issues such as costs, risks to human health, and ecological impacts that are associated with the application, development and commercialization of CNT-NC technology.  相似文献   

3.
Two studies of complicated ecological phenomena in Lake Maarsseveen (The Netherlands) are presented to illustrate that a combination of field and laboratory analysis might be a successful approach. In the first one, the yearly varying ratio of population abundance of two diatoms, Asterionella formosa and Fragilaria crotonensis during early spring is explained by a combination of abiotic and biotic factors. A fungal parasite blocks population development of the first species at temperatures higher than 3–5 °C . The second species then competes successfully for phosphate and develops a large population. The interaction between Asterionella and the fungus proved to be intricate. Several physiological mechanisms operate together and combined with variable climatic factors makes the prediction of what species will be dominant, impossible. In the second example diel vertical migration of the hybrid Daphnia galeata × hyalina is analysed in the field and the laboratory. Migration is confined to six to seven weeks in June–July when large shoals of juvenile perch are present in the pelagic zone of the lake. These fish exudate a kairomone that enhances the reaction of Daphnia to relative increases in light intensity of dawn. Especially accelerations in rate of relative increases enhance swimming velocity. The extent of enhancement depends, however, on the concentration of the kairomone and on food concentration. A Decision Making Mechanism is introduced and the relation between the response mechanism and the adaptive relevance of diel vertical migration is made.Finally considerations about research strategies and the importance of fundamental research are made. It is concluded that the development of limnology and aquatic ecology might be in danger when the present tendency to give prevalence to applied research continues.  相似文献   

4.
Using a combination of laboratory and field investigations, this study examined embryo mortality in the southern calamary Sepioteuthis australis as a function of egg mass size, the substrate upon which the mass is attached, the position of the embryo within the mass, and the degree of biofouling. Egg mass size ranged from 2 to 1,241 egg strands, however most masses consisted of 200–299 strands. Small egg masses (<300 strands) were generally attached to soft-sediment vegetation (Amphibolis antarctica, Heterozostera tasmanica, Caulerpa sp.), whereas larger masses (>300 strands) were either securely attached to robust macroalgae holdfasts (Ecklonia sp., Marcocystis pyrifera, Sargassum sp.) or unattached. Rates of embryo mortality were highly variable ranging from 2 to 25%. Both laboratory and field results indicated a positive relationship between egg mass size and embryo mortality. Larger, unattached egg masses contained twice as many dead embryos than those securely attached to a substrate. Mortality rates were significantly affected by the embryos’ relative position within the mass and were highest in embryos located near the attachment point of the egg strand, within the interior of the mass, and in close contact with the substrate. This was attributed to the inability of the embryos to respire adequately and eliminate metabolic wastes. Biofouling did not strongly influence embryo mortality, but colonisation occurred in areas conducive to growth, photosynthesis, and respiration indicating ‘healthy’ regions within the mass.  相似文献   

5.
Aporrectodea caliginosa is the most common endogeic (topsoil) earthworm in New Zealand and, because of its habitat, is potentially vulnerable to surface-applied pesticides. Lysosomal damage to earthworms, which can be visualized by the use of the neutral red retention assay (NRRA) has been evaluated in this species as a biomarker of organophosphate exposure. Earthworms were exposed in the laboratory to sub-lethal concentrations of chlorpyrifos and diazinon. In a semi-field experiment, earthworms were placed in mesocosms in a field sprayed with these pesticides at the rate recommended for a vegetable crop. In the laboratory, the neutral red retention time (NRRT) was significantly reduced following exposure to both pesticides compared with controls. In the semi-field experiment, earthworm NRRT was significantly reduced by both pesticides. These experiments have shown that the NRRA is very sensitive to exposure to chlorpyrifos and diazinon even at field rates. It therefore shows promise as a potential biomarker of contamination of soil by organophosphates.  相似文献   

6.
The photosynthesis of plankton sampled from the eutrophic Lake Loosdrecht was studied in Laboratory Scale Enclosures (LSEs) with regard to the rate of mixing. First, two LSEs were operated at different mixing rates. No significant differences in photosynthetic performance were found, with the exception of a depressed photosynthesis in the afternoon in the LSE which had a low mixing rate. Secondly, when mixing was stopped, the phytoplankton which stayed in the dark due to the steep light gradient in the LSE responded by changing its maximal photosynthetic capacity. The results show that the filamentous cyanobacteria in the lake can respond rapidly to changes in the depth of the mixed layer by altering their photosynthetic performance.This is publication 567 of the Centre for Estuarine and Coastal Ecology.  相似文献   

7.
Summary Predation by Saduria entomon on the depositfeeding amphipods Monoporeia (=Pontoporeia) affinis and Pontoporeia femorata was studied in laboratory experiments. Prey vulnerabilities were compared in singleprey treatments and in mixed-prey treatments, where the proportions of the two species were varied at one total density. In a pilot experiment, P. femorata was the more vulnerable prey, both in single-prey and mixed-prey treatments. In later experiments, the amphipod species were equally vulnerable in single-prey treatments, while in mixed-prey treatments Saduria preyed preferentially on M. affinis, even when this prey was rare, i.e. it did not switch. We suggest that the different result in the later experiments may have been due to a change in the search mode of the isopods.  相似文献   

8.
Aporrectodea caliginosa is the most common endogeic (topsoil) earthworm in New Zealand and, because of its habitat, is potentially vulnerable to surface-applied pesticides. Lysosomal damage to earthworms, which can be visualized by the use of the neutral red retention assay (NRRA) has been evaluated in this species as a biomarker of organophosphate exposure. Earthworms were exposed in the laboratory to sub-lethal concentrations of chlorpyrifos and diazinon. In a semi-field experiment, earthworms were placed in mesocosms in a field sprayed with these pesticides at the rate recommended for a vegetable crop. In the laboratory, the neutral red retention time (NRRT) was significantly reduced following exposure to both pesticides compared with controls. In the semi-field experiment, earthworm NRRT was significantly reduced by both pesticides. These experiments have shown that the NRRA is very sensitive to exposure to chlorpyrifos and diazinon even at field rates. It therefore shows promise as a potential biomarker of contamination of soil by organophosphates.  相似文献   

9.
Recent research in the protein intrinsic disorder was stimulated by the availability of accurate computational predictors. However, most of these methods are relatively slow, especially considering proteome-scale applications, and were shown to produce relatively large errors when estimating disorder at the protein- (in contrast to residue-) level, which is defined by the fraction/content of disordered residues. To this end, we propose a novel support vector Regression-based Accurate Predictor of Intrinsic Disorder (RAPID). Key advantages of RAPID are speed (prediction of an average-size eukaryotic proteome takes < 1 h on a modern desktop computer); sophisticated design (multiple, complementary information sources that are aggregated over an input chain are combined using feature selection); and high-quality and robust predictive performance. Empirical tests on two diverse benchmark datasets reveal that RAPID's predictive performance compares favorably to a comprehensive set of state-of-the-art disorder and disorder content predictors. Drawing on high speed and good predictive quality, RAPID was used to perform large-scale characterization of disorder in 200 + fully sequenced eukaryotic proteomes. Our analysis reveals interesting relations of disorder with structural coverage and chain length, and unusual distribution of fully disordered chains. We also performed a comprehensive (using 56000+ annotated chains, which doubles the scope of previous studies) investigation of cellular functions and localizations that are enriched in the disorder in the human proteome. RAPID, which allows for batch (proteome-wide) predictions, is available as a web server at http://biomine.ece.ualberta.ca/RAPID/.  相似文献   

10.
比较野生和人工繁育树鼩的部分生理指标,为人类疾病的动物模型创制提供基本参数.血液采自昆明地区54只野生树鼩(被捕获后人工饲养1-2月)和54只子一代人工繁育树鼩.该研究首次报道在两组动物中,肌酸激酶、肌钙蛋白I、总胆汁酸、果糖胺、低密度脂蛋白胆固醇等在性别间差异无显著性;这些指标在人工繁育树鼩中的中位数(四分位数间距)依次为:1449(956)U/L、5.94(7.23)μg/L、15.6(19.7)μmol/L、393.5(80.8)μmol/L和0.36(0.32)mmol/L;在野生树鼩中依次为:986(564)U/L、4.01(4.10)μg/L、20.0(20.6)μmol/L、379.0(104.0)μmol/L和0.46(0.23)mmol/L.人工繁育树鼩生理指标表现出个体间离散程度降低趋势,但个别反映肝脏功能及心肌情况的指标表现出平均值上升,个体离散程度扩大的现象.这些生理指标为人类疾病的树鼢模型创制打下了基础.  相似文献   

11.
谢琛静  徐斯翀  潘琦  周莉  孙祖越 《生物磁学》2014,(14):2763-2768
档案的建立和管理在药物非临床安全性评价和科学研究中都起到非常重要的作用。我们通过查阅文献发现,关于GLP机构档案管理的文献综述极少,涉及到将它与科研档案管理作系统全面的比较的文章是没有的。现从资料档案保存机构的硬件设施、档案管理规范和应注意的问题3个方面详细介绍了资料档案管理的相关规定和经验,并将GLP档案管理规范与科研档案管理规范作比较,我们根据国家档案局发布的《科学技术研究档案管理暂行规定》和7年GLP档案管理经验以及多次国家食品药品监督管理局(SFDA)认证现场检查的经历,总结出两者在功能实现、硬件设施、温湿度要求、档案防护、制定SOP、档案管理人员资质、各方人员职责、归档范围、归档形式、资料档案的接收与审查、归档时间、保管期限、借阅返还规定、资料的书写规范性、进出记录和电子文件的保存这16个方面的异同之处,突出GLP档案管理规范的特点和重点。通过这一深入全面的比较分析,得出GLP档案管理更加明确、具体、细致和可操作。  相似文献   

12.
档案的建立和管理在药物非临床安全性评价和科学研究中都起到非常重要的作用。我们通过查阅文献发现,关于GLP机构档案管理的文献综述极少,涉及到将它与科研档案管理作系统全面的比较的文章是没有的。现从资料档案保存机构的硬件设施、档案管理规范和应注意的问题3个方面详细介绍了资料档案管理的相关规定和经验,并将GLP档案管理规范与科研档案管理规范作比较,我们根据国家档案局发布的《科学技术研究档案管理暂行规定》和7年GLP档案管理经验以及多次国家食品药品监督管理局(SFDA)认证现场检查的经历,总结出两者在功能实现、硬件设施、温湿度要求、档案防护、制定SOP、档案管理人员资质、各方人员职责、归档范围、归档形式、资料档案的接收与审查、归档时间、保管期限、借阅返还规定、资料的书写规范性、进出记录和电子文件的保存这16个方面的异同之处,突出GLP档案管理规范的特点和重点。通过这一深入全面的比较分析,得出GLP档案管理更加明确、具体、细致和可操作。  相似文献   

13.
Summary The sites of uptake, decarboxylation and retention of 1-dopa and the uptake and retention of dopamine and 6-hydroxytryptamine in the small intestine of the guinea-pig have been localised histochemically with a fluorescence technique for arylethylamines. In segments of ileum from untreated guinea-pigs only noradrenergic axons are fluorescent; these axons were eliminated by surgical denervation (crushing nerves running to the intestine through the mesentery) or by chemical denervation with 6-hydroxydopamine. In denervated segments of ileum, cell bodies and processes of intrinsic neurons become fluorescent after the injection of 1-dopa, dopamine or 6-hydroxytryptamine and the inhibition of monoamine oxidase, as do cells of Brunner's glands and Paneth cells. About 11% of the nerve cell bodies in the submucous plexus and 0.4% of those in the myenteric plexus become fluorescent. Varicose intrinsic axons which take up amines are found amongst the nerve cell bodies of the myenteric and submucous plexuses. They also ramify in the principal connections of the plexuses, in the tertiary strands of the myenteric plexus, in the deep muscular plexus and contribute sparse supplies of axons to arterioles in the submucosa and to the lamina propria of the mucosa. The axons are resistant to the degenerative actions of 6-hydroxydopamine.It is suggested that the intrinsic amine handling axons are more likely to utilise an indolamine related to 5-hydroxytryptamine than they are to utilise a catecholamine as a neurotransmitter.  相似文献   

14.
Summary The influence of liming on soil solution composition was compared in two laboratory amended soils and one field amended soil. In the laboratory study, soil solutions were sampled by miscible displacement at intervals of 1 and 10 weeks after liming. In addition to increases in pH and Ca, there were large reductions in the concentrations of Mg, K, Na, Si and Mn. Solution concentration of free Al decreased with liming; however, organically complexed Al increased, as did soluble organic matter. Liming also stimulated mineralization of N as indicated by increased solution NO3 levels. The field amended soils were obtained from a long-term cutting trial investigating the effects of lime on pasture. Despite the passage of a 16-year interval since application, the effects of lime on soil solution characteristics were still clearly evident and generally consistent with those observed in the laboratory study. Estimated leaching losses of Ca from limed soil were relatively low, amounting to 12%, 27% and 44% of the 4.2, 8.4 and 12.5 t lime ha−1 applied, respectively. The results suggest that, in Eastern Ireland, a lime treatment would maintain and elevated pH and would influence the avialability and mobility of plant nutrients for some decades following application.  相似文献   

15.
In this study, bacteria isolated from a lake were characterised for their chlorine resistivity and the effects of chlorination on growth, mortality, protein expression and attachment propensity towards membranes. Biofouling and membrane performance were analysed. All isolated chlorine resistant strains, characterised by 16s rRNA gene sequencing, belonged to the genus Bacillus. Chlorination caused limited effects on bacterial growth and mortality. B. safensis and B. lechinoformis suffered the maximum effects due to chlorination. Live-to-dead ratios immediately after chlorination were above 1.3, with some exceptions. The membrane pure water flux recovery was highly strain dependent. Irreversible membrane fouling was observed with B. aquimaris. Membrane flux decreased substantially during ultrafiltration of water containing chlorine resistant bacteria.  相似文献   

16.
The acidification and warming of seawater have several impacts on marine organisms, including over microorganisms. The influence of acidification and warming of seawater on biofilms grown on API 5L steel surfaces was evaluated by sequencing the 16S ribosomal gene. For this, three microcosms were designed, the first simulating the natural marine environment (MCC), the second with a decrease in pH from 8.1 to 7.9, and an increase in temperature by 2 °C (MMS), and the third with pH in around 7.7 and an increase in temperature of 4 °C (MES). The results showed that MCC was dominated by the Gammaproteobacteria class, mainly members of the Alteromonadales Order. The second most abundant group was Alphaproteobacteria, with a predominance of Rhodobacterales and Oceanospirillales. In the MMS system there was a balance between representatives of the Gammaproteobacteria and Alphaproteobacteria classes. In MES there was an inversion in the representations of the most prevalent classes previously described in MCC. In this condition, there was a predominance of members of the Alphaproteobacteria Class, in contrast to the decrease in the abundance of Gammaproteobacteria members. These results suggest that possible future climate changes may influence the dynamics of the biofouling process in surface metals.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12088-021-00925-7.  相似文献   

17.
This experiment was carried out to investigate the long-term effects of enhancing cage complexity on behavioural measures of welfare in laboratory rats. We housed 72 rats in groups of four in either ‘enriched’ or ‘unenriched’ cages for six weeks. Scan and focal animal sampling were conducted in both the light and dark phase of the second, fourth and sixth weeks. Results revealed that rats in the ‘enriched’ cages showed longer durations of sleep behaviour, and low levels of agonistic behaviour compared to rats in the ‘unenriched’ cages. Results importantly demonstrated that the behavioural changes observed in the enriched environment were due to the presence of the enrichments themselves in the cages (indirect effects) and not due merely to rats interacting with the enrichment items in their environment. Thus, enhancing the complexity of conventional laboratory cages can promote behaviour such as longer bouts of sleep that is likely to be indicative of good welfare, and diminish levels of behaviour such as aggression that is likely to lead to poor welfare.  相似文献   

18.
 Because cannibals are potentially both predator and prey, the presence of conspecifics and alternative prey may act together to influence the rate at which cannibals prey upon each other or emigrate from a habitat patch. Wolf spiders (Lycosidae) are cannibalistic-generalist predators that hunt for prey with a sit-and-wait strategy characterized by changes in foraging site. Little information is available on how both prey abundance and the presence of conspecifics influence patch quality for these cursorial, non-web-building spiders. To address this question, laboratory experiments were conducted with spiderlings and older juveniles of the lycosid genus Schizocosa. The presence of insect prey consistently reduced rates of spider emigration when spiders were housed either alone or in groups. Solitary juvenile Schizocosa that had been recently collected from the field exhibited a median giving-up time (GUT) of 10 h in the absence of prey (Collembola); providing Collembola increased the median GUT to 64 h. For solitary spiders, the absence of prey increased by about fourfold the rate of emigration during the first 24 h. In contrast, for spiders in patches with a high density of conspecifics, the absence of prey increased the 24-h emigration rate by only 1.6-fold. For successful cannibals in the no-prey patches, the presence of conspecifics improved patch quality by providing a source of food. Mortality by cannibalism was affected by both prey availability and openness of the patch to net emigration. In patches with no net emigration, the presence of prey reduced rates of cannibalism from 79% to 57%. Spiders in patches open to emigration but not immigration experienced a rate of cannibalism (16%) that was independent of prey availability. The results of these experiments indicate that for a cannibalistic forager such as the wolf spider Schizocosa, (1) the presence of conspecifics can improve average patch quality when prey are absent, and (2) cannibalism has the potential to be a significant mortality factor under natural field conditions because cannibalism persisted in prey patches that were open to emigration. Received: 12 April 1996 / Accepted: 14 August 1996  相似文献   

19.
Cordylophora caspia is a hydrozoan which causes biofouling in power plants and is an increasing problem in UK drinking water treatment works. Thermal control is not usually feasible without a ready source of hot water so laboratory experiments were conducted to assess whether using pulsed doses of chlorine is an alternative solution. C. caspia polyps disintegrated after a single 20 min dose (the length of one backwash cycle in water treatment work filter beds) of 2.5 ppm chlorine. Without further treatment colonies regenerated within 3 days, but repeated dosing with chlorine for 20 min each day inhibited this regeneration. The resistance of surviving colonies to chlorine increased over time, although colony size and polyp regeneration continued to fall. These results suggest pulsed treatment with chlorinated backwashes at 2 ppm could be used to control C. caspia biofouling in rapid gravity filters and this may have relevance to other settings where thermal control is not feasible.  相似文献   

20.
The side effects of mancozeb on the predatory mite Typhlodromus pyri were studied in 4-year field trials on grapevine and in the laboratory. In the field, the effect of mancozeb varied according to previous mancozeb use. In vineyards where mancozeb had commonly been used over years, this fungicide is generally slightly toxic, in some cases moderately toxic and rarely toxic. In plots were mancozeb has never been used, its effect on T. pyri was more pronounced and varied from moderately toxic to toxic. Despite the toxicity of mancozeb, T. pyri populations have never been eradicated. Laboratory results obtained with the French CEB guideline no. 167 confirmed those of the 4-year field study: mancozeb was significantly more toxic to T. pyri populations collected in plots where it had rarely been used before the field experiment. In plots where mancozeb had been used for a long time, the susceptibility of T. pyri populations to this fungicide was reduced and female survival, fecundity but also viability of female progeny were less affected by mancozeb. Even though toxicity of mancozeb increased in controlled conditions, a significant correlation was established between field and laboratory results.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号