共查询到20条相似文献,搜索用时 38 毫秒
1.
Winfield J Ieropoulos I Greenman J Dennis J 《Bioprocess and biosystems engineering》2011,34(4):477-484
Microbial fuel cells (MFCs) can ‘treat’ wastewater but individually are thermodynamically restricted. Scale-up might, therefore,
require a plurality of units operating in a stack which could introduce losses simply through fluidic connections. Experiments
were performed on two hydraulically joined MFCs (20 cm apart) where feedstock flowed first through the upstream unit (MFCup) and into the downstream unit (MFCdown) to explore the interactive effect of electrical load connection, influent make-up and flow-rate on electrical outputs. This
set-up was also used to investigate how calculating total internal resistance based on a dynamic open circuit voltage (OCV)
might differ from using the starting OCV. When fed a highly conductive feedstock (~4,800 μS) MFCdown dropped approximately 180 mV as progressively heavier loads were applied to MFCup (independent of flow-rate) due to electron leakages through the medium. The conductivities of plain acetate solutions (5
and 20 mM) were insufficient to induce losses in MFCdown even when MFCup was operating at high current densities. However, at the highest flow-rate (240 mL/h) MFCdown dropped by approximately 100 mV when using 5 and 220 mV using 20 mM acetate. When the distance between MFCs was reduced by
5 cm, voltage drops were apparent even at lower flow-rates, (30 mL/h decreased the voltage by 115 mV when using 20 mM acetate).
Shear flow-rates can introduce dissolved oxygen and turbulence all capable of affecting the anodic biofilm and redox conditions.
Calculating total internal resistance using a dynamic OCV produced a more stable curve over time compared to that based on
the starting constant OCV. 相似文献
2.
Marie-Anne Pilette 《Inorganica chimica acta》2010,363(15):4253-4261
Reaction at pH = 2.3 of the [Mo2O2S2(OH2)6]2+ aqua cation with the tetravacant ion [β-B-HAs2W8O31]7− leads to the formation of a red solid from which three mixed salts have been obtained as single crystals and characterized by X-ray diffraction analysis. Three mixed salts K-5a, RbNa-5b, DMACs-5c exhibit a similar molecular arrangement consisting in three {β-HAs2W9O34} subunits mutually linked by three {Mo2O2S2} groups. The triangular arrangement delimits a large open-cavity, lined on the periphery by three outer {As-OH} groups and closed at the bottom by a small hexagonal pocket formed by six terminal oxygen atoms. The central hexagonal cavity is filled either by a potassium, a rubidium or a cesium cation. The outer {As-OH} groups are pointed towards two directions labelled up and down, respectively. In K-6a the three {As-OH} bonds are in up configuration leading to the {up, up, up} isomer. The structure of RbNa-5b is rather consistent with the superposition of the two {up, up, up} and {down, up, up} isomers disordered over the same crystallographic site, while only the {down, up, up} isomer is present in DMACs-5c. In solution, 183W NMR characterization of 6a as sodium salt results in a complicated spectrum consistent with the simultaneous presence of the four isomers, {up, up, up}, {down, up, up}, {down, down, up} and {down, down, down}, respectively. 5a reacts with three equivalents of iodine to give CsNa-6 isolated as single crystals. In 6, four β-{AsW9O33} moieties are located at the corner of a super tetrahedron and are mutually connected by six {Mo2O2S2} linkers. The three outer {As-OH} groups can be selectively removed by iodine, this oxidation reaction consisting in fact in a deprotecting process permitting the extension of the arrangement from triangular to tetrahedral. 相似文献
3.
Melamed O Barak O Silberberg G Markram H Tsodyks M 《Journal of computational neuroscience》2008,25(2):308-316
The synchronous oscillatory activity characterizing many neurons in a network is often considered to be a mechanism for representing,
binding, conveying, and organizing information. A number of models have been proposed to explain high-frequency oscillations,
but the mechanisms that underlie slow oscillations are still unclear. Here, we show by means of analytical solutions and simulations
that facilitating excitatory (E
f) synapses onto interneurons in a neural network play a fundamental role, not only in shaping the frequency of slow oscillations,
but also in determining the form of the up and down states observed in electrophysiological measurements. Short time constants and strong E
f synapse-connectivity were found to induce rapid alternations between up and down states, whereas long time constants and weak E
f synapse connectivity prolonged the time between up states and increased the up state duration. These results suggest a novel role for facilitating excitatory synapses onto interneurons in controlling
the form and frequency of slow oscillations in neuronal circuits. 相似文献
4.
Catabolite repression of the Bacillus subtilis gnt operon exerted by two catabolite-responsive elements 总被引:2,自引:1,他引:1
Yasuhiko Miwa. Kazuya Nagura Susumu Eguchi Hirokazu Fukuda Josef Deutscher Yasutaro Fujita 《Molecular microbiology》1997,23(6):1203-1213
Catabolite repression of Bacillus subtilis catabolic operons is supposed to occur via a negative regulatory mechanism involving the recognition of a cis-acting catabolite-responsive element (cre) by a complex of CcpA, which is a member of the GalR-LacI family of bacterial regulatory proteins, and the seryl-phos-phorylated form of HPr (P-ser-HPr), as verified by recent studies on catabolite repression of the gnt operon. Analysis of the gnt promoter region by deletions and point mutations revealed that in addition to the ere in the first gene (gntR) of the gnt operon (credown), this operon contains another ere located in the promoter region (creup). A translational gntR-lacZ fusion expressed under the control of various combinations of wild-type and mutant credown and creup was integrated into the chromosomal amyE locus, and then catabolite repression of p-galac-tosidase synthesis in the resultant integrants was examined. The in vivo results implied that catabolite repression exerted by creup was probably independent of catabolite repression exerted by credown; both creup and credown catabolite repression involved CcpA. Catabolite repression exerted by creup was independent of P-ser-HPr, and catabolite repression exerted by credown was partially independent of P-ser-HPr. DNase I footprinting experiments indicated that a complex of CcpA and P-ser-HPr did not recognize creup, in contrast to its specific recognition of credown. However, CcpA complexed with glucose-6-phosphate specifically recognized creup as well as credown, but the physiological significance of this complexing is unknown. 相似文献
5.
Jonathon S. Schofield Eric C. Parent Justin Lewicke Jason P. Carey Marwan El-Rich Samer Adeeb 《Journal of biomechanics》2013
Sit-to-stand transfer (STS) is a common yet critical prerequisite for many daily tasks. Literature conducted on healthy STS often assume the body to behave symmetrically across the left and right side; yet only a few studies have been conducted to investigate this supposition. These studies have focused on a single numerical indicator such as peak joint moment (JM) values to describe symmetricity; however, STS is a dynamic and time dependent movement. This study addresses the validity of peak value analyses through the introduction of a time based peak-offset measure and proposes two time-dependent techniques to further characterize asymmetry and assesses their feasibility in ten (10) healthy male participants. JM and joint power (JP) over the whole STS movement was determined using motion capture and inverse dynamics. Using a paired one-tailed t-test differences were found in the time at which the left and right side reached peak values in all lower extremity joints (p<0.05) with exception of the hip JM. Using a measure of JM and JP straight-difference it was determined that the ankle joint displayed the largest number of JM and JP development strategies of all the lower extremity joints. Finally, through numerical integration of the JM and JP data with respect to time, it was found that the longer one side spends dominating the movement, the larger the excess angular impulse and work that can be expected from that side. The results suggest that when analyzing STS movements, one must be aware of the potential asymmetry present even in healthy movements. Furthermore, a simple peak JM or JP analysis may not fully describe the extent of these asymmetries. 相似文献
6.
《Archives of animal nutrition》2013,67(3):201-210
Abstract The effects of different modes of inulin supplementation on caecal fermentation were evaluated in rats. Groups S and IN were fed diets containing 5% of sucrose or inulin, respectively, for the whole experimental period of 40 days. Group IN/S was fed IN and S diets, whereas group S/IN was fed S and IN diets, in the first and the second 20-day period, respectively. Groups INup and INdown were fed diets in which the content of inulin increased from 1 – 5% and decreased from 5 – 1%, every 8 days, respectively. The common effects of inulin on caecal fermentation, i.e. enlargement of tissue, acidification of digesta, a decrease in activities of potentially harmful bacterial enzymes (β-glucuronidase and β-glucosidase), and an increase in the total volatile fatty acids concentration and pool, were especially observed in the IN, S/IN and INup groups. The results suggested that the intensity of caecal fermentation is increased when inulin is present at a relatively high dietary level and that these changes are easily reversible after inulin withdrawal from feed. 相似文献
7.
Abdulbari Bener John Brebner Mohammed N. S. Atta James Gomes Fatih Ozkaragoz Mohammed Y. Cheema 《Aerobiologia》1997,13(1):11-15
The aim of this study, was to determine the prevalence of some respiratory symptoms and possible diseases among taxi drivers
and manual workers. This prospective study was performed on 165 Pakistani male drivers, (mean age: 34.5±7.8 years) and 165
Pakistani male manual workers not exposed to dust or fumes, without occupational exposure to driving employed in the Water
and Electricity Department and recruited as controls (mean age: 34.6±7.6 years and mean height and weight 169.8±6.0 cm and
71.9±10.9 kg). The data on chronic respiratory symptoms showed that taxi drivers had higher prevalence of symptoms than manual
workers, being significantly greater for asthma (RR=1.72; 95% CI=1.00–2.88,P=0.037); allergic rhinitis (RR=2.41; 95% CI=1.46–3.94,P=0.0006); dyspnea (RR=2.13; 95% CI=1.22–3.71,P=0.009); and nasal catarrh (RR=2.19; 95% CI=1.22–3.91,P=0.0106). Thirty percent of taxi drivers and 27% of manual workers were smokers, there was no significant differences in the
prevalence of chronic respiratory symptoms between smokers and non-smokers. Lung function parameters in the taxi drivers were
significantly lower than in manual workers group (P<0.0001) except PEF parameter. When comparing the measured mean values of lung function parameters in the drivers among smokers
and nonsmokers, there was no significant differences between smokers and nonsmokers. Also, a comparison of ventilatory capacity
of paired predicted values with measured normal values showed statistically significant differences between predicted and
measured values for taxi drivers and manual workers for FVC, FEV1, FEF25–75 and PEF parameters except for FEV1/FVC test in manual workers. In conclusion, the results of the present study provide evidence regarding effects of such as
carbon monoxide, nitrogen dioxide, sulfur dioxide and gases exposures on taxi drivers and long-term driving, which may be
associated with the development of chronic respiratory symptoms and lung function impairment. 相似文献
8.
D Coggon G Ntani KT Palmer VE Felli R Harari LH Barrero SA Felknor D Gimeno A Cattrell C Serra M Bonzini E Solidaki E Merisalu RR Habib F Sadeghian M Kadir SS Warnakulasuriya K Matsudaira B Nyantumbu MR Sim H Harcombe K Cox MH Marziale LM Sarquis F Harari R Freire N Harari MV Monroy LA Quintana M Rojas EJ Salazar Vega EC Harris S Vargas-Prada JM Martinez G Delclos FG Benavides M Carugno MM Ferrario AC Pesatori L Chatzi P Bitsios M Kogevinas K Oha T Sirk A Sadeghian RJ Peiris-John N Sathiakumar 《PloS one》2012,7(7):e39820
Background
The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.Methods/Principal Findings
A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).Conclusions/Significance
The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively. 相似文献9.
Although the primary sequence of kinases shows substantial divergence between unrelated eukaryotes, variation in the motifs that are actually phosphorylated by eukaryotic kinases is much smaller. Hence arrays developed for kinome profiling of mammalian cells are useful for kinome profiling of plant tissues as well, facilitating the study of plant signal transduction. We recently employed the Pepscan kinomics chip to reveal the small GTPases in plant sucrose signaling. Here we show that employing a different peptide library (the Pepscan kinase chip) largely similar results are obtained, confirming these earlier data, but such a different library also contributes new insights into the molecular details mediating plant cell responses to a sugar stimulus. Thus when studying plant signal transduction employing peptide arrays, using multiple platforms both increases the confidence of results and provides additional information.Key words: sucrose, arabidopsis, kinome profiling, kinase, MAPK, SnRK, casein kinase, tyrosine phosphorylation, CDC2, AGC kinaseIn our recently published paper1 we analyze the changes in the plant kinome after sucrose feeding compared to control sorbitol feeding of Arabidopsis. We employed kinomics chips (Pepscan Presto, The Netherlands) containing 960 different kinase consensus peptides selected for their importance in mammalian signal transduction. In addition we used kinase chips (Pepscan Presto, The Netherlands), containing 1,152 peptides covering the majority of peptides available through Phosphobase (version 2.0). These chips contain peptides derived from phosphorylation events described in many kingdoms and are taken from animals, plants, fungi and even bacteria.2,3 Full details as to the peptides spotted can be found at www. pepscanpresto.com. Results of the cluster analysis of three independent biological replicas of kinome profiling after treatment with water, sorbitol, sucrose and glucose are depicted in Figure 3A of our recent paper.1 A further analysis of this set of experiments was not given, due to a lower than expected biological reproducibility. In contrast to the >0.8 correlation observed for the set described in our recent paper, correlations of below 0.5 were seen for the experimental set analyzed on the kinase1 chips. However, we feel that some observation made based on these kinome profiles contain valuable information, if only to suggest follow-up experiments.Comparison of the kinome profiles of Arabidopsis treated with sucrose or sorbitol for 1 h revealed a set of 93 differentially phosphorylated consensus peptides, with the majority of 59 peptides showing reduced phosphorylation after sucrose treatment (Consensus Kinase sor vs. suc t-test P up/down ESSYSYEEI 0.0003 down PASPSPQRQ Cdk5-p23 0.0014 down PKRGSKDG AGC 0.0019 up IREESPPHS 0.0019 down RTPPPSG MAPK 0.0020 down PASQTPNKTt CDC2 0.0029 down STNEYMDMK PI3 kinase 0.0030 down SEENSKKTV CKI 0.0040 down APTPGGRR 0.0043 down RFTDTRKDE CaM-III 0.0046 down LSELSRRRI ds-RNA 0.0062 up PINGSPRTP CDC2 0.0065 down TEGQYELQP Tyr-K 0.0068 up KRAQISVRGL 0.0069 down AKRISGKMA 0.0069 up VVGGSLRGA AGC 0.0071 down KRPSNRAKA 0.0072 up ERQKTQTKL SnRK, MLCK 0.0073 down EEGISQESS 0.0080 up PVPEYINQS EGFR (Tyr-K) 0.0082 down FGHNTIDAV 0.0082 down ARVFSVLRE CaM-II 0.0085 down SNDDSDDDD CKII 0.0085 down GGVDYKNIH Tyr-K 0.0094 up SRSRSRSRS 0.0103 up SPSLSRHSS GSK3 0.0107 down RAKRSGSV 0.0120 down RRASLG AGC 1/2 0.0128 down GRASSHSSQ S6K 0.0129 down SGYISSLEY CKII 0.0139 down FFRRSKIAV AGC 0.0140 up STNDSPL beta-ARK 0.0145 down LRRASPG 0.0149 up SAVASNMRD GRK 0.0154 up KRPSGRAKA 0.0160 up KRSNSVDTS AGC 0.0165 down RQLRSPRRT CDC2 0.0171 up GRALSTRAQ CDPK, PhK 0.0172 down VSRTSAVPT AGC 0.0173 down TRKISQTAQ AGC 0.0174 down STTVSKTET 0.0180 down ESPASDEAE 0.0184 up LSYRGYSL PhK 0.0185 down DDINSYEAW 0.0186 up PNVSYIASR 0.0191 down KQPIYIVME FES (Tyr-K) 0.0195 up LVVASAGPT 0.0198 down TGFLTEYVA MAPKK 0.0198 up TEDQYSLVE Src 0.0212 up SSSSSPKAE MAPK 0.0213 up EKAKSPVPK 0.0221 down RRRASVA AGC1/2 0.0221 down APVASPAAP MAPK 0.0225 down LRRLSTKYR AGC1/2 0.0234 down EKHHSIDAQ 0.0256 down VRKRTLRRL SnRK, AGC 0.0266 down DLPGTEDFV GRK2 0.0277 down LSEHSSPEE CKII 0.0278 down KREASLDNQ AGC 0.0279 down TKKQSFKQT AGC 0.0280 up VRLRSSVPG autoP 0.0285 down KRPSLRAKA 0.0293 up PGPQSPGSP 0.0308 down YSGHSMSDP 0.0309 up ADGVYAASG FES (Tyr-K) 0.0311 up ENQASEEED CKII 0.0317 down TLASSFKRR AGC 0.0324 up TVKSSKGGP AGC 0.0326 down GVLRRASVA 0.0327 up SPRKSPRKS sperm-specific 0.0328 down PRRDSTEGF SnRK, AGC 0.0332 down RRRRAASVA 0.0346 down SRKDSLDDS GRK 0.0371 down ENPEYLGLD Tyr-K 0.0380 down KAKTTKKRP 0.0382 up RRPSV 0.0392 down QKAQTERKS AGC 0.0401 down AKAKTTKKR 0.0404 up GSDVSFNEE CKII 0.0409 down DEPSTPYHS GSK3 0.0409 down SSRPSSNRS CDPK, AGC 0.0411 up GGRASDYKS AGC 0.0413 up YMAPYDNYV Tyr-K 0.0420 up LELSDDDD CKII 0.0422 down THVASVSDV SnRK AMPK 0.0423 down SMANSFVGT PDKI 0.0427 down DLLTSPDVG CDC2 0.0441 down RGKSSSYSK AGC 0.0441 up SSSNTIRRP AGC 0.0453 up RRDSV 0.0457 down TKAASEKKS 0.0469 up DRLVSARSV CDPK, SnRK, AGC 0.0480 down RLSISTESQ AMPK 0.0489 up