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81.
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Objective: We tested the hypothesis that with similar weight gain the increase in blood pressure (BP) would be smaller in men with higher cardiorespiratory fitness (HCRF) than in men with lower cardiorespiratory fitness (LCRF). Research Methods and Procedures: Thirteen men (age = 23 ± 1, BMI = 24 ± 1) were overfed by ~1000 kcal/d over ~8 weeks to achieve a 5‐kg weight gain. Resting BP and 24‐hour ambulatory BP, body composition, and fat distribution were measured. Results: Cardiorespiratory fitness (CRF) was higher in the HCRF group compared with the LCRF group (49.9 ± 1.2 vs. 38.1 ± 1.4 mL/kg per minute, p < 0.001). At baseline, body weight was similar in the HCRF and LCRF groups, whereas the HCRF group displayed lower levels of total body fat (13.0 ± 1.7 vs. 16.9 ± 1.3 kg, p = 0.049) and abdominal visceral fat (49 ± 6 vs. 80 ± 14 cm2, p = 0.032). Resting BP and 24‐hour ambulatory BP were similar in the two groups at baseline. After weight gain, body weight increased ~5 kg (p < 0.05) in both groups; the changes in body composition and regional fat distribution were similar. As hypothesized, the increases in resting systolic (1 ± 2 vs. 7 ± 2 mm Hg; p = 0.008) and diastolic (?1 ± 4 vs. 5 ± 1 mm Hg; p = 0.005) BP were smaller in the HCRF group. CRF was correlated with the increases in resting systolic (r = ?0.64; p = 0.009) and diastolic BP (r = ?0.80; p < 0.001). Furthermore, the relationship between CRF and BP remained significant after adjusting for the changes in the proportion of total abdominal fat gained as visceral fat. Discussion: These findings suggest that higher levels of CRF are associated with a smaller increase in BP with weight gain, independently of changes in abdominal visceral fat.  相似文献   
83.
Probabilistic analyses allow the effect of uncertainty in system parameters on predicted model performance measures to be determined. Furthermore, using performance functions to describe a failure event, the probability of failure can be quantified. The effect of three-dimensional prosthesis shape optimization on the probabilistic response and failure probability of a cemented hip prosthesis system is investigated. Random variables include joint and muscle loading, cortical and cancellous bone and PMMA bone cement elastic properties, and strength parameters describing failure of the bone cement and the prosthesis-bone cement interface. Several performance functions describing the bone cement and prosthesis-cement interface are used to compute the probability of failure. When evaluated deterministically, most performance functions indicated a safe design, with the exception of interface tensile failure. However, when evaluated probabilistically, finite probabilities of failure were computed, some significant. The most likely mode of failure before shape optimization was prosthesis-bone cement interface tensile failure with a predicted probability of failure of 97.9%. Deterministic prosthesis shape optimization reduced the probability of failure for all performance functions and reduced prosthesis-bone cement interface tensile failure by 31.7%. Probability sensitivity factors indicate that the uncertainty in the joint loading, cement strength, and implant-cement interface strength have the greatest effect on the computed probability of failure. Implant shape optimization results in a more robust implant design that is less sensitive to uncertainties in joint loading, which cannot be easily controlled, and more sensitive to cement and interface properties, which are easier to modify.  相似文献   
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Different experimental strategies using short columns in both conventional liquid chromatography (HPLC) and ultra‐high pressure liquid chromatography (UHPLC) were evaluated to allow, for the first time with these techniques, the lipophilicity determination of compounds with log P>5. Various organic modifiers, stationary phases, and elution modes were tested on 14 rigid compounds with a CLogP between 5 and 8, and 38 compounds with log Poct from 0 to 5. The best results in HPLC were obtained with the 20‐mm Discovery ® RP Amide C16 stationary phase in isocratic mode using MeOH as organic modifier. To improve analysis time, the UHPLC approach was then evaluated. Consequently, a generic method was developed with a 30‐mm Acquity BEH Shield RP18 column in gradient mode using MeOH as organic modifier, allowing a fourfold gain of time compared to the HPLC method, for the highly lipophilic compounds tested. Finally, the most rapid and accurate results were obtained with a 10‐mm HypersilTM GOLD Javelin HTS stationary phase in UHPLC, enabling an eightfold gain of time compared to the HPLC method.  相似文献   
87.
The purpose of autonomic networking is to manage the business and technical complexity of networked components and systems. However, the lack of a common lingua franca makes it impossible to use vendor-specific network management data to ascertain the state of the network at any given time. Furthermore, the tools used to analyze management data are all different, and hence require different data in different formats. This complicates the construction of context from diverse information sources. This paper describes a new version of the DEN-ng context-aware policy model, which is part of the FOCALE autonomic network architecture. This model has been built using three guiding principles: (1) both the context model and the policy model are rooted in information models, so that they can govern managed entities, (2) each model is expressly constructed to facilitate the generation of ontologies, so that reasoning about policies constructed from the model may be done, and (3) the model is expressly constructed so that a policy language that supports machine-based reasoning and learning can be developed from it.
Keara BarrettEmail:
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88.
Proteorhodopsins (PRs) are widespread bacterial integral membrane proteins that function as light-driven proton pumps. Antarctic sea ice supports a complex community of autotrophic algae, heterotrophic bacteria, viruses, and protists that are an important food source for higher trophic levels in ice-covered regions of the Southern Ocean. Here, we present the first report of PR-bearing bacteria, both dormant and active, in Antarctic sea ice from a series of sites in the Ross Sea using gene-specific primers. Positive PR sequences were generated from genomic DNA at all depths in sea ice, and these sequences aligned with the classes Alphaproteobacteria, Gammaproteobacteria, and Flavobacteria. The sequences showed some similarity to previously reported PR sequences, although most of the sequences were generally distinct. Positive PR sequences were also observed from cDNA reverse transcribed from RNA isolated from sea ice samples. This finding indicates that these sequences were generated from metabolically active cells and suggests that the PR gene is functional within sea ice. Both blue-absorbing and green-absorbing forms of PRs were detected, and only a limited number of blue-absorbing forms were found and were in the midsection of the sea ice profile in this study. Questions still remain regarding the protein''s ecological functions, and ultimately, field experiments will be needed to establish the ecological and functional role of PRs in the sea ice ecosystem.Proteorhodopsins (PRs) are retinal binding bacterial integral membrane proteins that function as light-driven proton pumps (9, 10) and belong to the microbial rhodopsin superfamily of proteins (54). Since the first reported PR sequence from members of SAR86 clade marine (class Gammaproteobacteria) in 2000 (9), many other PR-bearing bacteria have been identified in a range of marine habitats (5, 18, 20, 24, 25, 46, 62). In the recent Global Ocean Sampling (GOS) expedition, almost 4,000 PR sequences from 41 distinct surface marine environments were acquired, demonstrating that these PR genes are extremely abundant in the genomes of ocean bacterioplankton (46). In fact, PR-containing bacteria account for 13% of the community in the Mediterranean Sea and Red Sea and 70% of the community in the Sargasso Sea (18, 46, 49, 60). These light-harvesting bacteria are present in three major marine classes of bacteria: the Alphaproteobacteria, Gammaproteobacteria, and Flavobacteria. In addition, two distinct PR genes encode pigments with “blue-absorbing” and “green-absorbing” properties, which is achieved by a substitution at a single amino acid position, which thereby functions as a spectral tuning switch (10, 37, 48).Sea ice represents a complex physicochemical environment in polar regions and covers up to 13% of the Earth''s surface (59). Although extreme gradients of temperature, salinity, nutrient availability, and light stratify the ice matrix from the surface to the ice-water interface (41), the sea ice habitat nevertheless supports a diverse microbial community of phytoplankton, Bacteria, Archaea, viruses, and protists that grow in liquid brine channels within the ice (14, 35, 56). This sea ice microbial community (SIMCO) is highly metabolically active despite being unable to avoid the extreme environmental conditions that they experience (39). In fact, very-high-standing stocks of the SIMCO exist in many regions of the Southern Ocean. For example, the concentration of chlorophyll a, a proxy for microalgal biomass, typically reaches 200 mg m2 in the Ross Sea, while the concentration of chlorophyll a in the water column below is approximately 2 orders of magnitude less (47), and the percentage of metabolically active bacteria (32% [39]) is significantly higher than the 10% observed for temperate marine systems (36). The SIMCO is thus a major source of biomass in ice-covered regions of the Southern Ocean (59), providing a critical food source for grazing zooplankton (and, consequently, also for higher trophic levels) for much of the year (3, 59). This biomass is of particular importance during the darkness of the polar winter, where the bottom-ice community is the only available food source for juvenile krill. These grazers absolutely rely on the sea ice microbial community to survive, as the water lacks other food sources (6, 28).In the past decade, reports of the widespread occurrence of bacteriochlorophyll and PR pigments in planktonic marine bacteria have challenged the assumption that chlorophyll a is the only principal light-capturing pigment in ocean surface waters. These alternative pigments may in fact play a critical role in light energy harvesting for microbial metabolism in various aquatic ecosystems (5, 10, 25, 40, 49). It has been proposed that energy, rather than nutrient conservation, is important for the regulation of productivity (7). PR-containing phototrophic eubacteria could play a significant role in the energy budget of cells in the photic zone in marine environments (15). PR sequences have been detected in the Southern Ocean (9), but to our knowledge, there have been no reports of PR-bearing bacteria within the sea ice matrix.The majority of the microbial rhodopsin genes found in oceanic samples have been detected by environmental sequencing (30, 46, 48, 60). We have used degenerate PR gene primers (5) in this study to positively identify PR-bearing operational taxonomic units (OTUs) from sea ice. Also, specific bacterial mRNA can now be detected from extracted nucleic acids and used to examine gene expression and, thus, infer metabolic activity (8). With this in mind, we have generated cDNA from RNA extracted from sea ice samples. From these observations, we deduce that PR-bearing bacteria are present in sea ice and may be actively contributing to the ecosystem within this extreme microenvironment.  相似文献   
89.
Mutations in X-linked ephrin-B1 in humans cause craniofrontonasal syndrome (CFNS), a disease that affects female patients more severely than males. Sorting of ephrin-B1–positive and –negative cells following X-inactivation has been observed in ephrin-B1+/− mice; however, the mechanisms by which mosaic ephrin-B1 expression leads to cell sorting and phenotypic defects remain unknown. Here we show that ephrin-B1+/− mice exhibit calvarial defects, a phenotype autonomous to neural crest cells that correlates with cell sorting. We have traced the causes of calvarial defects to impaired differentiation of osteogenic precursors. We show that gap junction communication (GJC) is inhibited at ectopic ephrin boundaries and that ephrin-B1 interacts with connexin43 and regulates its distribution. Moreover, we provide genetic evidence that GJC is implicated in the calvarial defects observed in ephrin-B1+/− embryos. Our results uncover a novel role for Eph/ephrins in regulating GJC in vivo and suggest that the pleiotropic defects seen in CFNS patients are due to improper regulation of GJC in affected tissues.  相似文献   
90.
We recorded bat activity on Zakynthos island (Greece) to test the hypotheses that (1) olive ( Olea europea ) groves and native woodlands provide comparable foraging habitat for insectivorous bats, (2) lower foraging activity occurs in olive groves treated with insecticide chemicals. We acoustically sampled bat activity (passes per minute) in four wooded habitats (organic and non-organic olive groves, oak woodland ( Quercus ilex and Quercus coccifera ) and pine ( Pinus halepensis ) woodland from June to August 2005. Habitat type did not affect overall bat activity. A single application of insecticide chemicals annually did not affect activity over traditional olive groves. Habitat use on the island differed in several ways from that reported in studies at mainland sites. Most strikingly, pine woodland supported higher bat activity than expected relative to other habitat types, and we recorded unexpectedly high levels of M. capaccinii activity in woodland habitats. We suggest that traditional olive groves buffer some bat species from the effects of deforestation. Conservation plans for Mediterranean bats should consider the biodiversity value of these groves along with the need to conserve small woodland patches. Finally, understanding island-specific patterns of habitat use is essential to bat conservation on small off-shore islands.  相似文献   
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