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41.
42.
Long-term cathode performance and the microbial communities that develop in microbial fuel cells fed different fermentation endproducts 总被引:1,自引:0,他引:1
Patrick D. KielyGeoffrey Rader John M. ReganBruce E. Logan 《Bioresource technology》2011,102(1):361-366
To better understand how cathode performance and substrates affected communities that evolved in these reactors over long periods of time, microbial fuel cells were operated for more than 1 year with individual endproducts of lignocellulose fermentation (acetic acid, formic acid, lactic acid, succinic acid, or ethanol). Large variations in reactor performance were primarily due to the specific substrates, with power densities ranging from 835 ± 21 to 62 ± 1 mW/m3. Cathodes performance degraded over time, as shown by an increase in power of up to 26% when the cathode biofilm was removed, and 118% using new cathodes. Communities that developed on the anodes included exoelectrogenic families, such as Rhodobacteraceae, Geobacteraceae, and Peptococcaceae, with the Deltaproteobacteria dominating most reactors. Pelobacter propionicus was the predominant member in reactors fed acetic acid, and it was abundant in several other MFCs. These results provide valuable insights into the effects of long-term MFC operation on reactor performance. 相似文献
43.
Heidi Goodrich-Blair Jean-Michel Ané James D. Bever Seth R. Bordenstein Monika Bright John M. Chaston Keith Clay Cameron R. Currie Angela E. Douglas Nicole Gerardo Maria J. Harrison Ruth E. Ley Margaret McFall-Ngai Arijit Mukherjee Bethany Rader Kenneth F. Raffa Edward G. Ruby Mary Beth Saffo Marc-André Selosse Justin L. Sonnenburg S. Patricia Stock Garret Suen Katarzyna Turnau Michael Udvardi Karen L. Visick Virginia M. Weis 《Symbiosis (Philadelphia, Pa.)》2010,51(1):1-12
Symbiosis, the intimate association between two or more organisms, is a fundamental component of biological systems. Our ability to understand the processes involved in the establishment and function of Symbiosis has critical consequences for the health of humans and the world we live in. For example, a deeper understanding of how legumes and insects have harnessed the nitrogen-fixing capacity of microbes can pave the way toward novel strategies to decrease fertilizer use. Also, using insect models to elucidate links between diet, gut microbiota, and toxin sensitivity not only has implications for biological control strategies, but also will lend insights into similar links in the human gut ecosystem. These types of ideas were presented and discussed at the 6th International Symbiosis Society Congress held in Madison, Wisconsin August, 2009. Over 300 participants from 20 countries attended the 7-day event, which featured cutting-edge symbiosis research from many different perspectives and disciplines. The conference was organized thematically, with oral sessions focused on Evolution, Ecology, Metabolism, the Host-Microbe Interface, Threats to Earth Systems, Symbiosis Models and the Human Microbiome, Viruses and Organelles, and Symbiosis Education. World-renowned scientists, post-doctoral fellows, and students were given the opportunity to describe their most recent discoveries. Session chairs provided overviews of their programs which highlight how the comparative analysis of different systems reveal common trends underlying symbiotic associations, what tools and theory are being developed that may be applied more broadly in symbiosis research, how symbiosis research contributing solutions to global issues such as emerging antibiotic resistance, a need for alternative energy sources, the pursuit of sustainable agriculture and natural resources, and how symbiotic systems are ideal for educating people about the fascinating natural world around us. The following paragraphs provide an overview of the research and discussions that took place during the congress. 相似文献
44.
By the age of 80 yr, the skeletal muscles of men and women decrease in mass and maximum force by approximately 30%. Severe contraction-induced injury may contribute to these age-related declines. One to two months after a 225 lengthening contraction protocol (LCP), muscles of young/adult male mice recovered completely, whereas those of old male mice sustained deficits of approximately 15% in mass and approximately 25% in maximum force. Although gender-related differences in the early events of contraction-induced injury have been reported, the recovery phase of muscles in old female animals has not been investigated. The hypothesis tested was that 2 mo after a severe LCP to the plantar flexor muscle group, the magnitude of recovery of mass and force for old female mice is less than that for adult female mice. The LCP was administered to muscles of adult and old, female C57BL/6 mice. At 3 days, 1 mo, and 2 mo following the LCP, maximum isometric force was measured, and muscles were removed and weighed. Two months following the LCP, the muscles of adult female mice recovered mass and force. In contrast, for old female mice, even after 2 mo, muscle masses were decreased by 11% and maximum forces by 38%. We conclude that, as reported previously for old male mice, a severe contraction-induced injury to muscles of old female mice results in prolonged deficits in mass and force. 相似文献
45.
A E Rader P G Rose M Rodriguez S Mansbacher D Pitlik F W Abdul-Karim 《Acta cytologica》1999,43(3):357-362
OBJECTIVE: To determine the significance of atypical squamous cells of undetermined significance (ASCUS) in patients 55 years or older. STUDY DESIGN: From January 1994, to January 1997, 8,175 cervicovaginal smears were obtained from patients 55 years or older (mean age, 64.8; range, 56-84) at University Hospitals of Cleveland. Ninety-six of these patients were diagnosed with ASCUS only or ASCUS with a qualifying statement on the smear. Patient records, follow-up cervicovaginal smears and biopsies were reviewed for a period of one to four years following the diagnosis of ASCUS. RESULTS: The incidence of ASCUS only or ASCUS with a qualifying statement for patients 55 years or older was 1.8%. The ASCUS:SIL ratio was 2.6:1. An estrogen stimulation test was recommended in two cases. Women older than 55 with ASCUS were three times more likely to be receiving hormonal replacement therapy than similar-aged women with normal cervicovaginal smears. Follow-up cervicovaginal smears or biopsies were obtained on 93 (80 cervicovaginal smears, 13 biopsies). The results were the following: LSIL (13), squamous carcinoma in situ (1) and ASCUS (53); the remainder of the cases were normal. In the patients who received a second diagnosis of ASCUS, follow-up cervi covaginal smears or biopsies revealed low grade dysplasia in six. CONCLUSION: Although the incidence of ASCUS and the frequency of underlying dysplasia is lower in postmenopausal women than the general population, there is still a real risk that a postmenopausal woman with ASCUS has underlying intraepithelial neoplasia. Therefore, these patients should be managed as is the general population. 相似文献
46.
Preservation of biodiversity depends on restoring the full range of historic environmental variation to which organisms have evolved, including natural disturbances. Lotic ecosystems have been fragmented by dams causing a reduction in natural levels of environmental variation (flow and temperature) and consequently a reduction of biodiversity in downstream communities. We conducted a long‐term study of the macroinvertebrate communities before and after natural flood disturbances in an unregulated reference site (natural flows and temperatures), a regulated site (regulated flows and temperatures), and a partially regulated reference site (regulated flows and natural temperatures) on the upper Colorado River downstream from a deep‐release storage reservoir. We aimed to test the hypothesis that floods and temperature restoration would cause an increase in macroinvertebrate diversity at the regulated site. Over the short term, macroinvertebrate richness decreased at the regulated site when compared to pre‐flood levels, whereas total macroinvertebrate density remained unchanged. Over the long term (1 and 10 years after the floods), macroinvertebrate diversity and community structure at the regulated site returned to pre‐flood levels without increasing to reference conditions. Occasional floods did not restore biodiversity in this system. As long as the physical state variables remain altered beyond a threshold, the community will return to its altered regulated condition. However, temperature restoration at the partially regulated site resulted in an increase in macroinvertebrate diversity. Our results indicate that restoration of the natural temperature regime will have a stronger effect on restoring biodiversity than occasional channel‐forming floods. 相似文献
47.
Robert J. Brown Andrew C. Edmondson Nathalie Griffon Theophelus B. Hill Ilia V. Fuki Karen O. Badellino Mingyao Li Megan L. Wolfe Muredach P. Reilly Daniel J. Rader 《Journal of lipid research》2009,50(9):1910-1916
Human endothelial lipase (EL) is a member of a family of lipases and phospholipases that are involved in the metabolism of plasma lipoproteins. EL displays a preference to hydrolyze lipids in HDL. We report here that a naturally occurring low frequency coding variant in the EL gene (LIPG), glycine-26 to serine (G26S), is significantly more common in African-American individuals with elevated HDL cholesterol (HDL-C) levels. To test the hypothesis that this variant results in reduced EL function, we extensively characterized and compared the catalytic and noncatalytic functions of the G26S variant and wild-type (WT) EL. While the catalytic-specific activity of G26S EL is similar to WT EL, its secretion is markedly reduced. Consistent with this observation, we found that carriers of the G26S variant had significantly reduced plasma levels of EL protein. Thus, this N-terminal variant results in reduced secretion of EL protein, plausibly leading to increased HDL-C levels. 相似文献
48.
Margaret E. Brousseau John S. Millar Margaret R. Diffenderfer Chorthip Nartsupha Bela F. Asztalos Megan L. Wolfe James P. Mancuso Andres G. Digenio Daniel J. Rader Ernst J. Schaefer 《Journal of lipid research》2009,50(7):1456-1462
This study was designed to establish the mechanism responsible for the increased apolipoprotein (apo) A-II levels caused by the cholesteryl ester transfer protein inhibitor torcetrapib. Nineteen subjects with low HDL cholesterol (<40 mg/dl), nine of whom were also treated with 20 mg of atorvastatin daily, received placebo for 4 weeks, followed by 120 mg of torcetrapib daily for the next 4 weeks. Six subjects in the nonatorvastatin cohort participated in a third phase, in which they received 120 mg of torcetrapib twice daily for 4 weeks. At the end of each phase, subjects underwent a primed-constant infusion of [5,5,5-2H3]l-leucine to determine the kinetics of HDL apoA-II. Relative to placebo, torcetrapib significantly increased apoA-II concentrations by reducing HDL apoA-II catabolism in the atorvastatin (−9.4%, P < 0.003) and nonatorvastatin once- (−9.9%, P = 0.02) and twice- (−13.2%, P = 0.02) daily cohorts. Torcetrapib significantly increased the amount of apoA-II in the α-2-migrating subpopulation of HDL when given as monotherapy (27%, P < 0.02; 57%, P < 0.003) or on a background of atorvastatin (28%, P < 0.01). In contrast, torcetrapib reduced concentrations of apoA-II in α-3-migrating HDL, with mean reductions of −14% (P = 0.23), −18% (P < 0.02), and −18% (P < 0.01) noted during the atorvastatin and nonatorvastatin 120 mg once- and twice-daily phases, respectively. Our findings indicate that CETP inhibition increases plasma concentrations of apoA-II by delaying HDL apoA-II catabolism and significantly alters the remodeling of apoA-II-containing HDL subpopulations. 相似文献
49.
Michael CW Chan Renee WY Chan Wendy CL Yu Carol CC Ho WH Chui CK Lo Kit M Yuen Yi Guan John M Nicholls JS Malik Peiris 《Respiratory research》2009,10(1):102