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51.

Background  

The objective of this study was to quantify the nuclear localization and DNA binding activity of p65, the major transactivating nuclear factor-kappa B (NF-kappaB) subunit, in full-thickness fetal membranes (FM) and myometrium in the absence or presence of term or preterm labor.  相似文献   
52.
* Linkages between plant growth rate and root responses to soil moisture heterogeneity were investigated. * Root dynamics were studied using genetically identical shoots (Vitis vinifera cv. Merlot) with genetically distinct root systems that promote higher (HSV) and lower (LSV) shoot growth rates (1103P and 101-14 Mgt, respectively). Three quantities of irrigation replenished different amounts of evapotranspiration (0, 40 and 100%ET(c)) in a California vineyard. * Roots of HSV vines exhibited more plasticity, as indicated by greater preferential growth in irrigated soil during the summer, and a larger shift in root diameter with a change in soil moisture than LSV vines. Higher tolerance of low soil moisture was not observed in LSV roots--root survivorship was similar for the two rootstocks. LSV vines produced a large fraction of its roots during the winter months and increased root density over the study, while HSV vines produced roots mainly in summer and only exhibited a high initial peak in root biomass in the first year. * These results demonstrated that a plant of higher vigor has greater morphological plasticity in response to lateral heterogeneity in soil moisture but similar tolerance to moisture stress as indicated by root survivorship in dry soil.  相似文献   
53.
Siderophore Utilization by Bradyrhizobium japonicum   总被引:1,自引:0,他引:1       下载免费PDF全文
Bradyrhizobium japonicum USDA 110 and 61A152 can utilize the hydroxamate-type siderophores ferrichrome and rhodotorulate, in addition to ferric citrate, to overcome iron starvation. These strains can also utilize the pyoverdin-type siderophore pseudobactin St3. The ability to utilize another organism's siderophores may confer a selective advantage in the rhizosphere.  相似文献   
54.
Mammals detect temperature with specialized neurons in the peripheral nervous system. Four TRPV-class channels have been implicated in sensing heat, and one TRPM-class channel in sensing cold. The combined range of temperatures that activate these channels covers a majority of the relevant physiological spectrum sensed by most mammals, with a significant gap in the noxious cold range. Here, we describe the characterization of ANKTM1, a cold-activated channel with a lower activation temperature compared to the cold and menthol receptor, TRPM8. ANKTM1 is a distant family member of TRP channels with very little amino acid similarity to TRPM8. It is found in a subset of nociceptive sensory neurons where it is coexpressed with TRPV1/VR1 (the capsaicin/heat receptor) but not TRPM8. Consistent with the expression of ANKTM1, we identify noxious cold-sensitive sensory neurons that also respond to capsaicin but not to menthol.  相似文献   
55.
56.
Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model.  相似文献   
57.
58.

Background

Systematic reviews of the literature occupy the highest position in currently proposed hierarchies of evidence. The aims of this study were to assess whether citation classics exist in published systematic review and meta-analysis (SRM), examine the characteristics of the most frequently cited SRM articles, and evaluate the contribution of different world regions.

Methods

The 100 most cited SRM were identified in October 2012 using the Science Citation Index database of the Institute for Scientific Information. Data were extracted by one author. Spearman’s correlation was used to assess the association between years since publication, numbers of authors, article length, journal impact factor, and average citations per year.

Results

Among the 100 citation classics, published between 1977 and 2008, the most cited article received 7308 citations and the least-cited 675 citations. The average citations per year ranged from 27.8 to 401.6. First authors from the USA produced the highest number of citation classics (n=46), followed by the UK (n=28) and Canada (n=15). The 100 articles were published in 42 journals led by the Journal of the American Medical Association (n=18), followed by the British Medical Journal (n=14) and The Lancet (n=13). There was a statistically significant positive correlation between number of authors (Spearman’s rho=0.320, p=0.001), journal impact factor (rho=0.240, p=0.016) and average citations per year. There was a statistically significant negative correlation between average citations per year and year since publication (rho = -0.636, p=0.0001). The most cited papers identified seminal contributions and originators of landmark methodological aspects of SRM and reflect major advances in the management of and predisposing factors for chronic diseases.

Conclusions

Since the late 1970s, the USA, UK, and Canada have taken leadership in the production of citation classic papers. No first author from low or middle-income countries (LMIC) led one of the most cited 100 SRM.  相似文献   
59.
Helix-helix interactions in the putative three-helix bundle formation of the gp41 transmembrane (TM) domain may contribute to the process of virus-cell membrane fusion in HIV-1 infection. In this study, molecular dynamics is used to analyze and compare the conformations of monomeric and trimeric forms of the TM domain in various solvent systems over the course of 4 to 23-ns simulations. The trimeric bundles of the TM domain were stable as helices and remained associated in a hydrated POPE lipid bilayer for the duration of the 23-ns simulation. Several stable inter-chain hydrogen bonds, mostly among the three deprotonated arginine residues located at the center of each of the three TM domains, formed in a right-handed bundle embedded in the lipid bilayer. No such bonds were observed when the bundle was left-handed or when the central arginine residue in each of the three TM helices was replaced with isoleucine (R_I mutant), suggesting that the central arginine residues may play an essential role in maintaining the integrity of the three-helix bundle. These observations suggest that formation of the three-helix bundle of the TM domain may play a role in the trimerization of gp41, thought to occur during the virus-cell membrane fusion process.  相似文献   
60.
BackgroundActivity-based funding (ABF) of hospitals is a policy intervention intended to re-shape incentives across health systems through the use of diagnosis-related groups. Many countries are adopting or actively promoting ABF. We assessed the effect of ABF on key measures potentially affecting patients and health care systems: mortality (acute and post-acute care); readmission rates; discharge rate to post-acute care following hospitalization; severity of illness; volume of care.MethodsWe undertook a systematic review and meta-analysis of the worldwide evidence produced since 1980. We included all studies reporting original quantitative data comparing the impact of ABF versus alternative funding systems in acute care settings, regardless of language. We searched 9 electronic databases (OVID MEDLINE, EMBASE, OVID Healthstar, CINAHL, Cochrane CENTRAL, Health Technology Assessment, NHS Economic Evaluation Database, Cochrane Database of Systematic Reviews, and Business Source), hand-searched reference lists, and consulted with experts. Paired reviewers independently screened for eligibility, abstracted data, and assessed study credibility according to a pre-defined scoring system, resolving conflicts by discussion or adjudication.ResultsOf 16,565 unique citations, 50 US studies and 15 studies from 9 other countries proved eligible (i.e. Australia, Austria, England, Germany, Israel, Italy, Scotland, Sweden, Switzerland). We found consistent and robust differences between ABF and no-ABF in discharge to post-acute care, showing a 24% increase with ABF (pooled relative risk  = 1.24, 95% CI 1.18–1.31). Results also suggested a possible increase in readmission with ABF, and an apparent increase in severity of illness, perhaps reflecting differences in diagnostic coding. Although we found no consistent, systematic differences in mortality rates and volume of care, results varied widely across studies, some suggesting appreciable benefits from ABF, and others suggesting deleterious consequences.ConclusionsTransitioning to ABF is associated with important policy- and clinically-relevant changes. Evidence suggests substantial increases in admissions to post-acute care following hospitalization, with implications for system capacity and equitable access to care. High variability in results of other outcomes leaves the impact in particular settings uncertain, and may not allow a jurisdiction to predict if ABF would be harmless. Decision-makers considering ABF should plan for likely increases in post-acute care admissions, and be aware of the large uncertainty around impacts on other critical outcomes.  相似文献   
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