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Sample records for high bacterial load

  1. High bacterial load in asymptomatic diabetic patients with neurotrophic ulcers retards wound healing after application of Dermagraft.

    Science.gov (United States)

    Browne, A C; Vearncombe, M; Sibbald, R G

    2001-10-01

    Diabetic neuropathic foot ulcers are a major healthcare burden. These chronic wounds always have a bacterial load, and although normal flora is not harmful, increased tissue burden may impede healing before clinical signs of infection are evident. In this study, chronic noninfected diabetic neuropathic foot ulcers (those with adequate blood supply and pressure offloading) were assessed for bacterial burden immediately before the application of a skin substitute. Eight patients with diabetic neuropathic foot ulcers greater than 1 cm2 and free of necrotic tissue had 3-mm tissue biopsies taken from the ulcer base for quantitative bacteriology. Five of the eight patients (75%) had greater or equal to 10(5) colony forming units/gram organisms present despite the absence of clinical signs of infection. Wound healing rates were linked to bacterial load as determined from quantitative biopsy--no growth was associated with a wound healing rate of 0.2 cm per week, 10(5) to 10(6) colony forming units/gram was associated with a healing rate of 0.15 cm per week, and greater than 10(6) colony forming units/gram was associated with 0.05 cm/per week healing rate. High bacterial burden impeded healing both before and after the application of the skin substitute. The authors will change their clinical practice to assess all diabetic neuropathic foot ulcers using quantitative skin biopsies before applying skin substitutes. All patients will be treated with combination antibiotics and repeat biopsies obtained with decreased bacterial burden (< 10(6) colony forming units/gram) prior to using any bioengineered skin substitute or growth factor treatment.

  2. Effect of high pressure pasteurization on bacterial load and bioactivity of Echinacea purpurea.

    Science.gov (United States)

    Chen, Xiu-Min; Hu, Chun; Raghubeer, Errol; Kitts, David D

    2010-09-01

    High hydrostatic pressure (HHP) technology was applied to organic Echinacea purpurea (E. purpurea) roots and flowers to determine the feasibility of using this technology for cold herb pasteurization, to produce microbiologically safe and shelf-stable products for the natural health products (NHPs) industry. HHP significantly (P purpurea methanol-derived extracts, evaluated in both chemical (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) [ABTS] and oxygen radical absorption capacity [ORAC] assay) and in cell culture models (RAW264, 7 macrophage, H(2)O(2)-induced intracellular oxidation, and lipopolysaccharide [LPS]-induced nitric oxide production), was not adversely affected by the application of HHP at both 2 and 5 min at 600 mPa. Furthermore, HHP did not affect the capacity of E. purpurea extracts to suppress nitric oxide production in LPS-activated macrophage cells. Therefore, our results show that HHP is an effective pasteurization process treatment to reduce microbial-contamination load while not adversely altering chemical and bioactive function of active constituents present in organic E. purpurea. Our study reports for the first time, the effectiveness of using high hydrostatic pressure (HHP) technology pressure to pasteurize E. purpurea root and flower, and the comparative retention of bioactive phytochemicals. Therefore, this technique can be used in food and natural health product industries to produce high-quality, microbiologically safe, and shelf-stable products.

  3. Characterization of the bacterial community involved in the bioflocculation process of wastewater organic matter in high loaded MBRs

    NARCIS (Netherlands)

    Faust, L.; Szendy, M.; Plugge, C.M.; Brink, van den P.F.; Temmink, H.; Rijnaarts, H.H.M.

    2015-01-01

    High-loaded membrane bioreactors (HL-MBRs), i.e., bioreactors equipped with a membrane for biomass retention and operated at extremely short sludge and hydraulic retention times, can concentrate sewage organic matter to facilitate subsequent energy and chemical recovery from these organics. Bioflocc

  4. Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads.

    Science.gov (United States)

    Robinson, Andrew L; Lee, Hyun Jung; Kwon, Junehee; Todd, Ewen; Rodriguez, Fernando Perez; Ryu, Dojin

    2016-02-01

    Hand washing and glove use are the main methods for reducing bacterial cross-contamination from hands to ready-to-eat food in a food service setting. However, bacterial transfer from hands to gloves is poorly understood, as is the effect of different durations of soap rubbing on bacterial reduction. To assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food after different soap washing times and glove use, participants' hands were artificially contaminated with Enterobacter aerogenes B199A at ∼9 log CFU. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities followed. The bacterial counts in diced tomatoes and on participants' hands and gloves were then analyzed. Different soap rubbing times did not significantly change the amount of bacteria recovered from participants' hands. Dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly less bacteria (P soap rubbing. Wearing gloves while dicing greatly reduced the incidence of contaminated tomato samples compared with dicing with bare hands. Increasing soap washing time decreased the incidence of bacteria recovered from outside glove surfaces (P bacterial cross-contamination in food service environments.

  5. Acidic electrolyzed water as a novel transmitting medium for high hydrostatic pressure reduction of bacterial loads on shelled fresh shrimp

    Directory of Open Access Journals (Sweden)

    Suping eDu

    2016-03-01

    Full Text Available Acidic electrolyzed water (AEW, a novel non-thermal sterilization technology, is widely used in the food industry. In this study, we firstly investigated the effect of AEW as a new pressure transmitting medium for high hydrostatic pressure (AEW-HHP processing on microorganisms inactivation on shelled fresh shrimp. The optimal conditions of AEW-HHP for Vibrio parahaemolyticus inactivation on sterile shelled fresh shrimp were obtained using response surface methodology: NaCl concentration to electrolysis 1.5 g/L, treatment pressure 400 MPa, treatment time 10 min. Under the optimal conditions mentioned above, AEW dramatically enhanced the efficiency of HHP for inactivating V. parahaemolyticus and Listeria monocytogenes on artificially contaminated shelled fresh shrimp, and the log reductions were up to 6.08 and 5.71 log10 CFU/g respectively, while the common HHP could only inactivate the two pathogens up to 4.74 and 4.31 log10 CFU/g respectively. Meanwhile, scanning electron microscopy (SEM showed the same phenomenon. For the naturally contaminated shelled fresh shrimp, AEW-HHP could also significantly reduce the micro flora when examined using plate count and PCR-DGGE. There were also no significant changes, histologically, in the muscle tissues of shrimps undergoing the AEW-HHP treatment. In summary, using AEW as a new transmitting medium for HHP processing is an innovative non thermal technology for improving the food safety of shrimp and other aquatic products.

  6. Bacterial Load in Expressed and Stored Breast Milk of Lactating ...

    African Journals Online (AJOL)

    Bacterial Load in Expressed and Stored Breast Milk of Lactating Mothers in Abia ... Using antiseptic procedures, breast milk samples were collected from these 20 ... bacteria isolated in the breast milk samples under both storage conditions.

  7. High Power Disk Loaded Guide Load

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Z.D.; /SLAC

    2006-02-22

    A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.

  8. Transient pauses of the bacterial flagellar motor at low load

    Science.gov (United States)

    Nord, A. L.; Pedaci, F.; Berry, R. M.

    2016-11-01

    The bacterial flagellar motor (BFM) is the molecular machine responsible for the swimming and chemotaxis of many species of motile bacteria. The BFM is bidirectional, and changes in the rotation direction of the motor are essential for chemotaxis. It has previously been observed that many species of bacteria also demonstrate brief pauses in rotation, though the underlying cause of such events remains poorly understood. We examine the rotation of Escherichia coli under low mechanical load with high spatial and temporal resolution. We observe and characterize transient pauses in rotation in a strain which lacks a functional chemosensory network, showing that such events are a phenomenon separate from a change in rotational direction. Rotating at low load, the BFM of E. coli exhibits about 10 pauses s-1, lasting on average 5 ms, during which time the rotor diffuses with net forwards rotation. Replacing the wild type stators with Na+ chimera stators has no substantial effect on the pausing. We discuss possible causes of such events, which are likely a product of a transient change in either the stator complex or the rotor.

  9. Molecular diagnosis of bacterial vaginosis: Does adjustment for total bacterial load or human cellular content improve diagnostic performance?

    Science.gov (United States)

    Plummer, E L; Garland, S M; Bradshaw, C S; Law, M G; Vodstrcil, L A; Hocking, J S; Fairley, C K; Tabrizi, S N

    2017-02-01

    We investigated the utility of quantitative PCR assays for diagnosis of bacterial vaginosis and found that while the best model utilized bacterial copy number adjusted for total bacterial load (sensitivity=98%, specificity=93%, AUC=0.95[95%CI=0.93,0.97]), adjusting for total bacterial or human cell load did not consistently increase the diagnostic performance of the assays. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. TE(01) High Power Disk Loaded Guide Load

    CERN Document Server

    Farkas, Zoltan D

    2005-01-01

    A method to design a matching section from a smooth guide to a disk loaded guide, using a variation of broadband matching* is described. Using this method, we show how to design high power loads, filters and attenuators. The load consists of a disk loaded coaxial guide, operating in the T01

  11. The Relation between Oral Candida Load and Bacterial Microbiome Profiles in Dutch Older Adults

    Science.gov (United States)

    Kraneveld, Eefje A.; Buijs, Mark J.; Bonder, Marc J.; Visser, Marjolein; Keijser, Bart J. F.; Crielaard, Wim; Zaura, Egija

    2012-01-01

    Currently there are no evidence-based ecological measures for prevention of overgrowth and subsequent infection by fungi in the oral cavity. The aim of this study was to increase our knowledge on fungal–bacterial ecological interactions. Salivary Candida abundance of 82 Dutch adults aged 58–80 years was established relative to the bacterial load by quantitative PCR analysis of the Internal Transcribed (ITS) region (Candida) and 16S rDNA gene (bacteria). The salivary microbiome was assessed using barcoded pyrosequencing of the bacterial hypervariable regions V5–V7 of 16S rDNA. Sequencing data was preprocessed by denoising and chimera removal, clustered in Operational Taxonomic Units (OTUs) and assigned to taxonomy. Both OTU-based (PCA, diversity statistics) and phylogeny-based analyses (UniFrac, PCoA) were performed. Saliva of Dutch older adults contained 0–4 × 108 CFU/mL Candida with a median Candida load of 0.06%. With increased Candida load the diversity of the salivary microbiome decreased significantly (pCandida load correlated positively with class Bacilli, and negatively with class Fusobacteria, Flavobacteria, and Bacteroidia. Microbiomes with high Candida load were less diverse and had a distinct microbial composition towards dominance by saccharolytic and acidogenic bacteria - streptococci. The control of the acidification of the oral environment may be a potential preventive measure for Candida outgrowth that should be evaluated in longitudinal clinical intervention trials. PMID:22900048

  12. Relationship between Milk Microbiota, Bacterial Load, Macronutrients, and Human Cells during Lactation.

    Science.gov (United States)

    Boix-Amorós, Alba; Collado, Maria C; Mira, Alex

    2016-01-01

    Human breast milk is considered the optimal nutrition for infants, providing essential nutrients and a broad range of bioactive compounds, as well as its own microbiota. However, the interaction among those components and the biological role of milk microorganisms is still uncovered. Thus, our aim was to identify the relationships between milk microbiota composition, bacterial load, macronutrients, and human cells during lactation. Bacterial load was estimated in milk samples from a total of 21 healthy mothers through lactation time by bacteria-specific qPCR targeted to the single-copy gene fusA. Milk microbiome composition and diversity was estimated by 16S-pyrosequencing and the structure of these bacteria in the fluid was studied by flow cytometry, qPCR, and microscopy. Fat, protein, lactose, and dry extract of milk as well as the number of somatic cells were also analyzed. We observed that milk bacterial communities were generally complex, and showed individual-specific profiles. Milk microbiota was dominated by Staphylococcus, Pseudomonas, Streptococcus, and Acinetobacter. Staphylococcus aureus was not detected in any of these samples from healthy mothers. There was high variability in composition and number of bacteria per milliliter among mothers and in some cases even within mothers at different time points. The median bacterial load was 10(6) bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods. Furthermore, milk bacteria were present in a free-living, "planktonic" state, but also in equal proportion associated to human immune cells. There was no correlation between bacterial load and the amount of immune cells in milk, strengthening the idea that milk bacteria are not sensed as an infection by the immune system.

  13. Relationship between milk microbiota, bacterial load, macronutrients and human cells during lactation

    Directory of Open Access Journals (Sweden)

    Alba eBOIX-AMORÓS

    2016-04-01

    Full Text Available Human breast milk is considered the optimal nutrition for infants, providing essential nutrients and a broad range of bioactive compounds, as well as its own microbiota. However, the interaction among those components and the biological role of milk microorganisms is still uncovered. Thus, our aim was to identify the relationships between milk microbiota composition, bacterial load, macronutrients and human cells during lactation. Bacterial load was estimated in milk samples from a total of 21 healthy mothers through lactation time by bacteria-specific qPCR targeted to the single-copy gene fusA . Milk microbiome composition and diversity was estimated by 16S-pyrosequencing and the structure of these bacteria in the fluid was studied by flow cytometry, qPCR and microscopy. Fat, protein, lactose and dry extract of milk as well as the number of somatic cells were also analyzed. We observed that milk bacterial communities were generally complex, and showed individual-specific profiles. Milk microbiota was dominated by Staphylococcus, Pseudomonas, Streptococcus and Acinetobacter. Staphylococcus aureus was not detected in any of these samples from healthy mothers. There was high variability in composition and number of bacteria per milliliter among mothers and in some cases even within mothers at different time points. The median bacterial load was 106 bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods.. Furthermore, milk bacteria were present in a free-living, planktonic state, but also in equal proportion associated to human immune cells. There was no correlation between bacterial load and the amount of immune cells in milk, strengthening the idea that milk bacteria are not sensed as an infection by the immune system.

  14. Interventions to reduce the bacterial load in recycled broiler litter.

    Science.gov (United States)

    Vaz, C S L; Voss-Rech, D; de Avila, V S; Coldebella, A; Silva, V S

    2017-03-23

    Two experiments were undertaken to evaluate the bacterial load in recycled litter between broiler flocks following addition of quicklime (T1), windrowing (T2), shallow fermentation (T3), and control (no intervention, T4). The first experiment was developed in field conditions in which the broiler houses were accompanied by 6 consecutive flocks and the effect of the treatments was assessed on enterobacteria and aerobic mesophiles. The second experiment was conducted in an experimental broiler house with recycled litter for assessment of Salmonella Enteritidis phage type 4 (SE PT4). In the field study, T3 presented the best results in reducing enterobacteria in broiler litter in relation to the other treatments, with the highest reduction occurring in the first 3 flocks, tending to stabilization from the fourth flock onward for all the treatments assessed. From the third to sixth flocks, enterobacteria level at the end of the treatments (d 12) was lower than the average in the fresh litter, except in T4. All treatments reduced aerobic mesophiles throughout the flocks, where T2 showed the highest reduction. The percentage of dry matter in the broiler litter diminished in T4 and increased in T3 over the course of the flocks. In the second experiment, the drop in the SE PT4 level in the broiler litter first occurred in T2 and T3. However, all the treatments except for T4 eliminated SE PT4 within 12 d. The temperature of the broiler litter in T2 was higher in relation to the other treatments. The results show that litter treatment prior to reutilization by the successive broiler flock is required to reduce the level of residual bacteria. The fermentative treatments (T2 and T3) were found to be superior to the others in terms of reducing the bacterial load, with shallow fermentation standing out with the highest reduction of enterobacteria and equivalent SE PT4 elimination when compared to windrowing.

  15. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  16. Polymer brushes under high load.

    Directory of Open Access Journals (Sweden)

    Suzanne M Balko

    Full Text Available Polymer coatings are frequently used to provide repulsive forces between surfaces in solution. After 25 years of design and study, a quantitative model to explain and predict repulsion under strong compression is still lacking. Here, we combine experiments, simulations, and theory to study polymer coatings under high loads and demonstrate a validated model for the repulsive forces, proposing that this universal behavior can be predicted from the polymer solution properties.

  17. The effect of a commercial UV disinfection system on the bacterial load of shell eggs.

    NARCIS (Netherlands)

    Reu, de K.; Grijspeerdt, K.; Hermann, L.M.; Heyndrickx, M.; Uytendaele, M.; Debevere, J.; Putirulan, F.F.; Bolder, N.M.

    2006-01-01

    Aims: To study the effect of UV irradiation on the bacterial load of shell eggs and of a roller conveyor belt. Methods and Results: The natural bacterial load on the eggshell of clean eggs was significantly reduced by a standard UV treatment of 4.7 s; from 4.47 to 3.57 log CFU per eggshell. For very

  18. The Molecular Bacterial Load Assay Replaces Solid Culture for Measuring Early Bactericidal Response to Antituberculosis Treatment

    Science.gov (United States)

    Mtafya, Bariki; Phillips, Patrick P. J.; Hoelscher, Michael; Ntinginya, Elias N.; Kohlenberg, Anke; Rachow, Andrea; Rojas-Ponce, Gabriel; McHugh, Timothy D.; Heinrich, Norbert

    2014-01-01

    We evaluated the use of the molecular bacterial load (MBL) assay, for measuring viable Mycobacterium tuberculosis in sputum, in comparison with solid agar and liquid culture. The MBL assay provides early information on the rate of decline in bacterial load and has technical advantages over culture in either form. PMID:24871215

  19. Relationship between the Presence of Bartonella Species and Bacterial Loads in Cats and Cat Fleas (Ctenocephalides felis) under Natural Conditions.

    Science.gov (United States)

    Gutiérrez, Ricardo; Nachum-Biala, Yaarit; Harrus, Shimon

    2015-08-15

    Cats are considered the main reservoir of three zoonotic Bartonella species: Bartonella henselae, Bartonella clarridgeiae, and Bartonella koehlerae. Cat fleas (Ctenocephalides felis) have been experimentally demonstrated to be a competent vector of B. henselae and have been proposed as the potential vector of the two other Bartonella species. Previous studies have reported a lack of association between the Bartonella species infection status (infected or uninfected) and/or bacteremia levels of cats and the infection status of the fleas they host. Nevertheless, to date, no study has compared the quantitative distributions of these bacteria in both cats and their fleas under natural conditions. Thus, the present study explored these relationships by identifying and quantifying the different Bartonella species in both cats and their fleas. Therefore, EDTA-blood samples and fleas collected from stray cats were screened for Bartonella bacteria. Bacterial loads were quantified by high-resolution melt real-time quantitative PCR assays. The results indicated a moderate correlation between the Bartonella bacterial loads in the cats and their fleas when both were infected with the same Bartonella species. Moreover, a positive effect of the host infection status on the Bartonella bacterial loads of the fleas was observed. Conversely, the cat bacterial loads were not affected by the infection status of their fleas. Our results suggest that the Bartonella bacterial loads of fleas are positively affected by the presence of the bacteria in their feline host, probably by multiple acquisitions/accumulation and/or multiplication events.

  20. APS high heat load monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.K.; Mills, D.

    1993-02-01

    This document contains the design specifications of the APS high heat load (HHL) monochromator and associated accessories as of February 1993. It should be noted that work is continuing on many parts of the monochromator including the mechanical design, crystal cooling designs, etc. Where appropriate, we have tried to add supporting documentation, references to published papers, and calculations from which we based our decisions. The underlying philosophy behind performance specifications of this monochromator was to fabricate a device that would be useful to as many APS users as possible, that is, the design should be as generic as possible. In other words, we believe that this design will be capable of operating on both bending magnet and ID beamlines (with the appropriate changes to the cooling and crystals) with both flat and inclined crystal geometries and with a variety of coolants. It was strongly felt that this monochromator should have good energy scanning capabilities over the classical energy range of about 4 to 20 keywith Si (111) crystals. For this reason, a design incorporating one rotation stage to drive both the first and second crystals was considered most promising. Separate rotary stages for the first and second crystals can sometimes provide more flexibility in their capacities to carry heavy loads (for heavily cooled first crystals or sagittal benders of second crystals), but their tuning capabilities were considered inferior to the single axis approach.

  1. Biomechanical Loading Modulates Proinflammatory and Bone Resorptive Mediators in Bacterial-Stimulated PDL Cells

    Directory of Open Access Journals (Sweden)

    Andressa Vilas Boas Nogueira

    2014-01-01

    Full Text Available The present study aimed to evaluate in vitro whether biomechanical loading modulates proinflammatory and bone remodeling mediators production by periodontal ligament (PDL cells in the presence of bacterial challenge. Cells were seeded on BioFlex culture plates and exposed to Fusobacterium nucleatum ATCC 25586 and/or cyclic tensile strain (CTS of low (CTSL and high (CTSH magnitudes for 1 and 3 days. Synthesis of cyclooxygenase-2 (COX2 and prostaglandin E2 (PGE2 was evaluated by ELISA. Gene expression and protein secretion of osteoprotegerin (OPG and receptor activator of nuclear factor kappa-B ligand (RANKL were evaluated by quantitative RT-PCR and ELISA, respectively. F. nucleatum increased the production of COX2 and PGE2, which was further increased by CTS. F. nucleatum-induced increase of PGE2 synthesis was significantly (P<0.05 increased when CTSH was applied at 1 and 3 days. In addition, CTSH inhibited the F. nucleatum-induced upregulation of OPG at 1 and 3 days, thereby increasing the RANKL/OPG ratio. OPG and RANKL mRNA results correlated with the protein results. In summary, our findings provide original evidence that CTS can enhance bacterial-induced syntheses of molecules associated with inflammation and bone resorption by PDL cells. Therefore, biomechanical, such as orthodontic or occlusal, loading may enhance the bacterial-induced inflammation and destruction in periodontitis.

  2. TE_01 High Power Disk Loaded Guide Load

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Z.D.; /SLAC

    2005-06-01

    A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads, attenuators and filters. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.

  3. High voltage load resistor array

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  4. The effect of organic loading on bacterial community composition of membrane biofilms in a submerged polyvinyl chloride membrane bioreactor.

    Science.gov (United States)

    Xia, Siqing; Li, Jixiang; He, Shuying; Xie, Kang; Wang, Xiaojia; Zhang, Yanhao; Duan, Liang; Zhang, Zhiqiang

    2010-09-01

    The effect of organic loading on bacterial community composition of membrane biofilms was investigated using a submerged polyvinyl chloride membrane bioreactor. The low and high loadings were set at 0.33 and 0.52 gCOD/(gVSSd), respectively. The results showed that membrane fouling occurred earlier and faster under the high loading conditions. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that the similarity of bacterial community in the membrane biofilms between the two loadings was 0.67, higher than that in the mixed liquors (0.52-0.55), which indicated that some specific bacteria were selected preferentially on the membranes. Clone library analysis of the membrane biofilms indicated that Betaproteobacteria and Bacteroidetes under the high loading were 54.72% and 19.81%, respectively. Microarray results further confirmed that the two bacteria were the dominant microorganisms in the high loading biofilm. The severe membrane fouling may be aroused mainly by the enrichment of the two bacteria under the high loading.

  5. Effect of species, breed, and age on bacterial load in bovine and bubaline semen

    Directory of Open Access Journals (Sweden)

    Chandrahas Sannat

    2015-04-01

    Full Text Available Aim: The present study was conducted to investigate the effect of species, breed and age on bacterial load in fresh and frozen semen of Cattle and Buffalo bull. Materials and Methods: Present study covered 56 cow and 10 buffalo bulls stationed at Central Semen Station Anjora, Durg (Chhattisgarh. Impact of breeds on bacterial load in semen was assessed using six breeds of cattle viz. Sahiwal, Gir, Red Sindhi, Tharparkar, Jersey and Holstein Friesian (HF cross. Cow bulls were categorized into four different groups based on their age ( 6 years to study variation among age groups. Bacterial load was measured in fresh and frozen semen samples from these bulls using the standard plate count (SPC method and count was expressed as colony forming unit (CFU per ml of semen. Results: Higher bacterial load was reported in fresh (2.36 × 104 ± 1943 CFU/ml and frozen (1.00 × 10 ± 90 CFU/ml semen of cow bulls as compared to buffalo bulls (1.95 × 104 ± 2882 and 7.75 × 102 ± 160 CFU/ml in fresh and frozen semen, respectively. Jersey bull showed significantly higher bacterial count (p < 0.05 both in fresh (4.07 × 104 ± 13927 CFU/ ml and frozen (1.92 × 103 ± 178 CFU/ml semen followed by HF cross, Sahiwal, Gir, Red Sindhi and Tharparkar bull. Bulls aged < 4 years and more than 6 years yielded increased bacterial load in their semen. Although a minor variation was reported between species and among age groups, no significant differences were measured. Conclusion: Bacterial load in semen did not differ significantly between species and age groups; however significant variation was reported among different breeds. Bulls of Jersey breed showed significantly higher bacterial load in semen as compared to the crossbred and indigenous bull.

  6. Autonomous Generation and Loading of DNA Guides by Bacterial Argonaute.

    Science.gov (United States)

    Swarts, Daan C; Szczepaniak, Malwina; Sheng, Gang; Chandradoss, Stanley D; Zhu, Yifan; Timmers, Elizabeth M; Zhang, Yong; Zhao, Hongtu; Lou, Jizhong; Wang, Yanli; Joo, Chirlmin; van der Oost, John

    2017-03-16

    Several prokaryotic Argonaute proteins (pAgos) utilize small DNA guides to mediate host defense by targeting invading DNA complementary to the DNA guide. It is unknown how these DNA guides are being generated and loaded onto pAgo. Here, we demonstrate that guide-free Argonaute from Thermus thermophilus (TtAgo) can degrade double-stranded DNA (dsDNA), thereby generating small dsDNA fragments that subsequently are loaded onto TtAgo. Combining single-molecule fluorescence, molecular dynamic simulations, and structural studies, we show that TtAgo loads dsDNA molecules with a preference toward a deoxyguanosine on the passenger strand at the position opposite to the 5' end of the guide strand. This explains why in vivo TtAgo is preferentially loaded with guides with a 5' end deoxycytidine. Our data demonstrate that TtAgo can independently generate and selectively load functional DNA guides.

  7. Autonomous Generation and Loading of DNA Guides by Bacterial Argonaute

    NARCIS (Netherlands)

    Swarts, Daan C.; Szczepaniak, Malwina; Sheng, Gang; Chandradoss, Stanley D.; Zhu, Yifan; Timmers, Elizabeth M.; Zhang, Yong; Zhao, Hongtu; Lou, Jizhong; Wang, Yanli; Joo, Chirlmin; Oost, van der John

    2017-01-01

    Several prokaryotic Argonaute proteins (pAgos) utilize small DNA guides to mediate host defense by targeting invading DNA complementary to the DNA guide. It is unknown how these DNA guides are being generated and loaded onto pAgo. Here, we demonstrate that guide-free Argonaute from Thermus thermophi

  8. Controlled release and antibacterial activity of tetracycline hydrochloride-loaded bacterial cellulose composite membranes.

    Science.gov (United States)

    Shao, Wei; Liu, Hui; Wang, Shuxia; Wu, Jimin; Huang, Min; Min, Huihua; Liu, Xiufeng

    2016-07-10

    Bacterial cellulose (BC) is widely used in biomedical applications. In this study, we prepared an antibiotic drug tetracycline hydrochloride (TCH)-loaded bacterial cellulose (BC) composite membranes, and evaluated the drug release, antibacterial activity and biocompatibility. The structure and morphology of the fabricated BC-TCH composite membranes were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TCH release results show that the incorporation of BC matrix to load TCH is able to control the release. In vitro antibacterial assay demonstrate that the developed BC-TCH composites displayed excellent antibacterial activity solely associated with the loaded TCH drug. More importantly, the BC-TCH composite membranes display good biocompatibility. These characteristics of BC-TCH composite membranes indicate that they may successfully serve as wound dressings and other medical biomaterials.

  9. Fungal and Bacterial Infection Mitigation with Antibiotic and Antifungal Loaded Biopolymer Sponges

    Science.gov (United States)

    Parker, Ashley Cox

    Musculoskeletal injuries are some of the most prevalent injuries in both civilian and military populations and their infections can be difficult to treat, often resulting in multiple surgeries and increased costs. In both previous and recent military operations, extremity injuries have been the most common battlefield injuries and many involve complex, open fractures. These extremity injuries are especially susceptible to multiple pathogenic, and sometimes drug resistant, bacteria and fungi. Fungal infections have recently become increasingly problematic in both military and civilian populations and have significantly higher amputation rates than those from bacterial infections. Many of these bacterial and fungal strains adhere to tissue and implanted orthopaedic hardware within wounds, forming biofilms. These problematic, often polymicrobial, infections threaten the health of the patient, but the risk also exists of spreading within hospitals to become prominent resistant infections. Local antimicrobial delivery releases high levels of antimicrobials directly to injured wound tissue, overcoming sub-bactericidal or subfungicidal antimicrobial levels present in the avascular wound zones. This research will determine the ability of modified chitosan sponges, buffered with sodium acetate or blended with polyethylene glycol (PEG), to act as short term adjunctive therapies to initial surgical treatment for delivering both antibiotics and/or antifungals for early abatement of infection. The objective of this work was to evaluate both types of modified sponges for in vitro and in vivo material characteristics and device functionality. In vitro analysis demonstrated both the buffered and PEG modified chitosan sponges exhibited increased degradation and functional cytocompatibility. The chitosan/PEG sponges were able to be loaded with hydrophobic antifungals and the sponges released in vitro biologically active concentrations, alone or in combination with the antibiotic

  10. Bacterial load of German cockroach (Blattella germanica) found in hospital environment

    Science.gov (United States)

    Menasria, Taha; Moussa, Fatima; El-Hamza, Souad; Tine, Samir; Megri, Rochdi; Chenchouni, Haroun

    2014-01-01

    Background Cockroaches are among the most common pests in public dwellings and health facilities. Their presence can raise safety concerns, especially as they maybe carriers of pathogenic organisms. Methods This study was carried out to isolate and identify the bacterial flora from German cockroaches (Blattella germanica). Cockroaches collected by hand catches from two public hospital environments in Tebessa city (northeast Algeria) were screened for microbial load from their external surfaces and alimentary tract using standard bacterial protocols. Results A total of 174 bacterial isolates were isolated from 39 German cockroach specimens. The most common and abundant bacterial species belonged to the Pseudomonas group (23.5%) and Serratia (13.2%). Pathogens like Staphylococcus aureus were also isolated, as well as opportunistic pathogens like Klebsiella species and food spoilage bacteria such as Enterobacter and Citrobacter species were isolated from both external surface and digestive tract of the insect. Generalized linear models (GLM) were performed to analyze the variation of abundances and occurrences of bacterial isolates harboured by B. germanica. The GLMs revealed that the main factors affecting variation of bacterial diversity and abundance were sex and hospital (P cockroach acts as reservoir and potential vector of some bacterial pathogens. PMID:24766338

  11. Effect of vaginal douching and different semen extenders on bacterial load and fertility in turkeys.

    Science.gov (United States)

    Omprakash, A V; Venkatesh, G

    2006-08-01

    1. A study on artificial insemination of Beltsville Small White turkeys investigated the effect on bacterial load and fertility of vaginal douching with diluents containing Gentamicin 400 microg/ml and different semen extenders. 2. Irrespective of the extenders used, vaginal douching with Gentamicin reduced the microbial load of the vagina with resultant improvement in fertility and hatchability and corresponding reduction in embryonic mortality. 3. Eggs from hens inseminated with semen extended with Beltsville Poultry Semen Extender (BPSE) diluent along with vaginal douching showed a trend towards higher per cent fertility and per cent hatchability of total and fertile eggs set compared to other extenders, though this was non-significant.

  12. High temperature bacterial leaching: HIOX project

    Energy Technology Data Exchange (ETDEWEB)

    Morin, D.; D' Hugues, P.; Bonney, C. F.; Norris, P.; Shwab, W.; Sundkvist, J-E.; Bridges, P. [Bureau de Recherhes Geologiques et Minieres, Orleans (France)

    2001-07-01

    The HIOX project was designed to investigate the use of thermophilic bacterial cultures for the leaching of chalcopyrite (CuFeS{sub 2}, the natural source of copper). Beyond bacterial leaching, the study also encompassed the downstream processing steps in an effort to develop a new method for the recovery of copper in an economical and environmentally-friendly process. Using the HIOX process copper recovery was increased to better than 90 per cent within 5 days with a 12 per cent solids culture, although some potentially limiting factors such as foam generation, nutrient concentrations and mixing/aeration efficiency were also identified. The study resulted in the establishment of a mass balance based on a simplified flowsheet of the process. Techno-economic evaluation carried out at three sites indicated technical feasibility using relatively conventional equipment and capital and operating costs in ranges that suggest that bioleaching with high temperature bacteria is an attractive alternative for the treatment of chalcopyrite concentrate. 5 tabs.

  13. Bacterial load of fresh vegetables and their resistance to the currently used antibiotics in Saudi Arabia.

    Science.gov (United States)

    Hassan, Sabry A; Altalhi, Abdullah D; Gherbawy, Youssuf A; El-Deeb, Bahig A

    2011-09-01

    This study was carried out to describe the bacterial load and the occurrence of some disease-causing enteric bacteria on raw vegetables sold in Saudi markets. The study further aimed to analyze antibiotic resistance rates, production of extended-spectrum beta lactamase, and plasmid carriage among bacterial population of raw vegetables. Results revealed that none of them contained Bacillus cereus, Salmonella, and Escherichia coli O157:H7. However, Staphylococcus aureus and Shigella were detected in 11.8% and 4.4% of the samples, respectively. The bacterial loads ranged from 3 to 8 log(10) CFUg(-1) for aerobic bacteria and 1 to 4 log(10) CFUg(-1) for coliforms as well as Enterobacteriaceae. The isolates exhibited resistance in decreasing order for ampicillin (76.5%), cephalothin (69.5%), trimethoprime-sulfamethoxazole (36.7%), aminoglycosides (21.9%), tetracycline (17.2%), fluoroquinolones (17.2%), amoxycillin-clavulanic acid (13.3%), and chloramphenicol (7.8%). Maximum resistance to extended-spectrum beta-lactam antibiotics occurred in 14.8% of isolates and the production of extended-spectrum beta-lactamase was achieved by 2.3% of isolates. Multiple resistances to four or more antimicrobial agents along with plasmid with varied sizes were documented. These investigations indicate the occurrence of antibiotic resistance and plasmid carriage among bacterial isolates populating raw vegetables.

  14. Diversity of Dominant Bacterial Taxa in Activated Sludge Promotes Functional Resistance following Toxic Shock Loading

    KAUST Repository

    Saikaly, Pascal

    2010-12-14

    Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30 min IC50 or the concentration of toxicant that results in a 50% reduction in oxygen utilization rate compared to a referential state represented by a control receiving no toxicant. Biodiversity of dominant bacterial taxa was assessed using polymerase chain reaction-terminal restriction fragment length polymorphism (PCR-T-RFLP) targeting the 16S ribosomal RNA (16S rRNA) gene. Statistical analysis of 30 min IC50 values and PCR-T-RFLP data showed a significant positive correlation (P<0.05) between functional resistance and microbial diversity for each of the three toxicants tested. To our knowledge, this is the first study showing a positive correlation between biodiversity of dominant bacterial taxa in activated sludge and functional resistance. In this system, activated sludge bacterial communities with higher biodiversity are functionally more resistant to disturbance caused by toxic shock loading. © 2010 Springer Science+Business Media, LLC.

  15. Effect of preputial washing on bacterial load and preservability of semen in Murrah buffalo bulls

    Directory of Open Access Journals (Sweden)

    G. S. Meena

    2015-06-01

    Full Text Available Aim: To study the effect of preputial washing on bacterial load, preservability and semen quality in Murrah buffalo bulls Materials and Methods: A total of 36 collections of three Murrah buffalo bulls maintained at Artificial Breeding Research Centre, ICAR-National Dairy Research Institute, Karnal, were collected at weekly intervals from each bull without preputial washing and latter ejaculates from same bull with preputial washing by infusing normal saline (0.85%, KMnO4 (0.02% and savlon (2.0% to first, second and third bull, respectively. The microbial load and semen quality were evaluated during different hours of storage at refrigerated temperature (0, 24 and 48 h and after thrawing of cryopreserved (at −196°C semen. Results: The results of preservation of semen at refrigerated temperature showed that bacterial load was markedly lower in ejaculates of bulls subjected to preputial washing. Semen preserved at refrigerator temperature and cryopreserved, the effect of washing solution was significant for individual motility (IM, non-eosiniphilic count, hypo-osmotic swelling reactivity (HOST, total plate count (TPC and acrosome integrity. KMnO4 was found to be the best in lowering bacterial load, sperm abnormalities and in improving semen quality such as motility, non-eosinophilic count, HOST and acrosome integrity even up to 48 h of preservation and cryopreserved semen. Effect of duration of preservation and stage of cryopreservation was also significant for IM, non-eosiniphilic count, HOST, sperm abnormalities and acrosome integrity. Conclusion: Overall the results suggested that preputial washing with KMnO4 solution improved the semen quality and reduced microbial load of Murrah buffalo bull’s semen preserved at refrigerated temperature and cryopreservation.

  16. Eggshell bacterial load is related to antimicrobial properties of feathers lining barn swallow nests.

    Science.gov (United States)

    Peralta-Sánchez, Juan Manuel; Soler, Juan José; Martín-Platero, Antonio Manuel; Knight, Rob; Martínez-Bueno, Manuel; Møller, Anders Pape

    2014-02-01

    The use of feathers to line bird's nests has traditionally been interpreted as having a thermoregulatory function. Feather-degrading bacteria growing on feathers lining nests may have antimicrobial properties, which may provide an additional benefit to lining nests with feathers. We test the hypothesis that the production of antimicrobial substances by feather bacteria affects the microbiological environment of the nest, and therefore the bacterial density on eggshells and, indirectly, hatching success. These effects would be expected to differ between nests lined with pigmented and white feathers, because bacteria grow differently on feathers of different colors. We experimentally manipulated the composition of pigmented and unpigmented feathers in nests of the barn swallow (Hirundo rustica) and studied the antimicrobial properties against the keratin-degrading bacterium Bacillus licheniformis of bacteria isolated from feathers of each color. Analyzed feathers were collected at the end of the incubation period, and antimicrobial activity was defined as the proportion of bacteria from the feathers that produce antibacterial substances effective against B. licheniformis. Our experimental manipulation affected antimicrobial activity, which was higher in nests with only white feathers at the beginning of incubation. Moreover, white feathers showed higher antimicrobial activity than black ones. Interestingly, antimicrobial activity in feathers of one of the colors correlated negatively with bacterial density on feather of the opposite color. Finally, antimicrobial activity of white feathers was negatively related to eggshell bacterial load. These results suggest that antimicrobial properties of feathers in general and of white feathers in particular affect the bacterial environment in nests. This environment in turn affects the bacterial load on eggshells, which may affect hatching success.

  17. Assembly and Mechanical Properties of the Cargo-Free and Cargo-Loaded Bacterial Nanocompartment Encapsulin.

    Science.gov (United States)

    Snijder, Joost; Kononova, Olga; Barbu, Ioana M; Uetrecht, Charlotte; Rurup, W Frederik; Burnley, Rebecca J; Koay, Melissa S T; Cornelissen, Jeroen J L M; Roos, Wouter H; Barsegov, Valeri; Wuite, Gijs J L; Heck, Albert J R

    2016-08-08

    Prokaryotes mostly lack membranous compartments that are typical of eukaryotic cells, but instead, they have various protein-based organelles. These include bacterial microcompartments like the carboxysome and the virus-like nanocompartment encapsulin. Encapsulins have an adaptable mechanism for enzyme packaging, which makes it an attractive platform to carry a foreign protein cargo. Here we investigate the assembly pathways and mechanical properties of the cargo-free and cargo-loaded nanocompartments, using a combination of native mass spectrometry, atomic force microscopy and multiscale computational molecular modeling. We show that encapsulin dimers assemble into rigid single-enzyme bacterial containers. Moreover, we demonstrate that cargo encapsulation has a mechanical impact on the shell. The structural similarity of encapsulins to virus capsids is reflected in their mechanical properties. With these robust mechanical properties encapsulins provide a suitable platform for the development of nanotechnological applications.

  18. Inhibited Bacterial Adhesion and Biofilm Formation on Quaternized Chitosan-Loaded Titania Nanotubes with Various Diameters

    Directory of Open Access Journals (Sweden)

    Wen-tao Lin

    2016-03-01

    Full Text Available Titania nanotube-based local drug delivery is an attractive strategy for combating implant-associated infection. In our previous study, we demonstrated that the gentamicin-loaded nanotubes could dramatically inhibit bacterial adhesion and biofilm formation on implant surfaces. Considering the overuse of antibiotics may lead to the evolution of antibiotic-resistant bacteria, we synthesized a new quaternized chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC with a 27% degree of substitution (DS; referred to as 27% HACC that had a strong antibacterial activity and simultaneously good biocompatibility with osteogenic cells. Titania nanotubes with various diameters (80, 120, 160, and 200 nm and 200 nm length were loaded with 2 mg of HACC using a lyophilization method and vacuum drying. Two standard strain, methicillin-resistant Staphylococcus aureus (American Type Culture Collection 43300 and Staphylococcus epidermidis (American Type Culture Collection 35984, and two clinical isolates, S. aureus 376 and S. epidermidis 389, were selected to investigate the bacterial adhesion at 6 h and biofilm formation at 24, 48, and 72 h on the HACC-loaded nanotubes (NT-H using the spread plate method, confocal laser scanning microscopy (CLSM, and scanning electron microscopy (SEM. Smooth titanium (Smooth Ti was also investigated and compared. We found that NT-H could significantly inhibit bacterial adhesion and biofilm formation on its surface compared with Smooth Ti, and the NT-H with 160 nm and 200 nm diameters had stronger antibacterial activity because of the extended HACC release time of NT-H with larger diameters. Therefore, NT-H can significantly improve the antibacterial ability of orthopedic implants and provide a promising strategy to prevent implant-associated infections.

  19. High power evaluation of X-band high power loads

    CERN Document Server

    Matsumoto, Shuji; Syratchev, Igor; Riddone, Germana; Wuensch, Walter

    2010-01-01

    Several types of X-band high power loads developed for several tens of MW range were designed, fabricated and used for high power tests at X-band facility of KEK. Some of them have been used for many years and few units showed possible deterioration of RF performance. Recently revised-design loads were made by CERN and the high power evaluation was performed at KEK. In this paper, the main requirements are recalled, together with the design features. The high power test results are analysed and presented

  20. Do Milk Samples Stored for 12 Days after Collection Exhibit a Change in Composition Related to the Initial Bacterial Load?

    Science.gov (United States)

    de Freitas, Larissa Nazareth; Cassoli, Laerte Dagher; da Silva, Janielen; de Figueiredo Pantoja, José Carlos; Machado, Paulo Fernando

    2016-05-01

    Total bacterial count (TBC) is a tool used to assess milk quality and is associated with not only the initial sample contamination but also the sample storage time and temperature. Several countries have reported milk samples with a high TBC, and the influence of TBC on milk preservation remains unclear. Thus, the aim of this study was to evaluate the impact of the initial bacterial contamination level on the macrocomponents and somatic cell count (SCC) of raw milk samples preserved with bronopol and maintained at two storage temperatures (7 and 25°C) for up to 12 days. Thus, we collected milk samples from 51 dairy farms, which were divided into two groups according to the initial bacterial load: low TBC (<100,000 CFU/ml) and high TBC (≥100,000 CFU/ml). We analyzed the sample composition for protein, fat, total solids, lactose, milk urea nitrogen, and the SCC. We did not observe an effect from TBC and storage time and temperature on the concentration of protein, fat, total solids, and lactose. SCC changes were not observed for samples maintained under refrigeration (7°C); however, samples maintained at room temperature (25°C) exhibited a decrease in the SCC beginning on day 6 of storage. For milk urea nitrogen, values increased when the samples were maintained at room temperature, beginning on the ninth storage day. Samples with the preservative bronopol added and maintained under refrigeration may be analyzed up to 12 days after collection, regardless of the milk microbial load.

  1. Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis.

    Science.gov (United States)

    Svahn, Sara L; Ulleryd, Marcus A; Grahnemo, Louise; Ståhlman, Marcus; Borén, Jan; Nilsson, Staffan; Jansson, John-Olov; Johansson, Maria E

    2016-04-01

    Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics,S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival.

  2. Health Effects of Alkaline Diet and Water, Reduction of Digestive-tract Bacterial Load, and Earthing.

    Science.gov (United States)

    Mousa, Haider Abdul-Lateef

    2016-04-01

    In the article, the author discusses the issue of chronic, low-grade acidosis that is thought to be brought about primarily by 2 factors: (1) advancing age, with a consequent decline in renal function; and (2) diet. An acid-forming diet can induce low-grade metabolic acidosis, which causes very small decreases in blood pH and plasma bicarbonate (HCO3-) that remain within the range considered to be normal. However, if the duration of the acidosis is prolonged or chronically present, even a low degree of acidosis can become significant. This article reviews supporting evidence in the literature that has shown that consumption of abundant alkaline-forming foods can result in improvement in bone mineral density (BMD) and muscle mass, protection from chronic illnesses, reduced tumor-cell invasion and metastasis, and effective excretion of toxins from the body. In addition, a large number of studies showing the benefits of alkaline water (mineral water) have revealed that people consuming water with a high level of total dissolved solids (TDS) (ie, with a high mineral content) have shown a lower incidence of coronary heart disease (CHD), cardiovascular disease (CVD), and cancer and lower total mortality rates. Consumption of alkaline water also may prevent osteoporosis and protect pancreatic beta cells with its antioxidant effects. In addition, this article discusses the literature that shows that reducing digestive-tract bacterial load can play an important role in increasing blood alkalinity toward the normal upper limit. That change occurs through good oral hygiene, flossing of teeth, perfect chewing of food, and bowel evacuation as soon as possible. Finally, the author reviews the literature that shows that earthing (ie, the direct contact of the human body with the earth) can supply a current of plentiful electrons. Earthing has been shown to reduce acute and chronic inflammation, blood glucose in patients with diabetes, red blood cell (RBC) aggregation, and blood

  3. High-pressure saline washing of allografts reduces bacterial contamination.

    Science.gov (United States)

    Hirn, M Y; Salmela, P M; Vuento, R E

    2001-02-01

    60 fresh-frozen bone allografts were contaminated on the operating room floor. No bacterial growth was detected in 5 of them after contamination. The remaining 55 grafts had positive bacterial cultures and were processed with three methods: soaking in saline, soaking in antibiotic solution or washing by high-pressure saline. After high-pressure lavage, the cultures were negative in three fourths of the contaminated allografts. The corresponding figures after soaking grafts in saline and antibiotic solution were one tenth and two tenths, respectively. High-pressure saline cleansing of allografts can be recommended because it improves safety by reducing the superficial bacterial bioburden.

  4. Can dressings soaked with polyhexanide reduce bacterial loads in full-thickness skin grafting? A randomized controlled trial.

    Science.gov (United States)

    Saleh, Karim; Sonesson, Andreas; Persson, Kerstin; Riesbeck, Kristian; Schmidtchen, Artur

    2016-12-01

    Polyhexamethylene biguanide (PHMB)-based antiseptic solutions can reduce bacterial loads in different clinical settings and are believed to lower risk of infections. We sought to assess the efficacy of a PHMB-based solution in lowering bacterial loads of full-thickness skin grafting wounds and the risk of surgical site infections (SSIs). In this double-blinded clinical trial, 40 patients planned for facial full-thickness skin grafting were randomized 1:1 to receive tie-over dressings soaked with either PHMB-based solution or sterile water. Quantitative and qualitative bacterial analysis was performed on all wounds before surgery, at the end of surgery, and 7 days postoperatively. In addition, all patients were screened for nasal colonization of Staphylococcus aureus. Analysis of wounds showed no statistically significant difference in bacterial reductions between the groups. The SSI rates were significantly higher in the intervention group (8/20) than in the control group (2/20) (P = .028). Higher postoperative bacterial loads were a common finding in SSIs (P = .011). This was more frequent when S aureus was present postoperatively (P = .034), intraoperatively (P = .03), and in patients with intranasal S aureus colonization (P = .007). Assessment of SSIs is largely subjective. In addition, this was a single-center study and the total number of participants was 40. Soaking tie-over dressings with PHMB solution in full-thickness skin grafting had no effect on postoperative bacterial loads and increased the risk of SSI development. The presence of S aureus intranasally and in wounds preoperatively and postoperatively increased postoperative bacterial loads, which in turn resulted in significantly more SSIs. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  5. Neisseria gonorrhoeae Bacterial DNA Load in the Pharynges and Saliva of Men Who Have Sex with Men.

    Science.gov (United States)

    Chow, Eric P F; Tabrizi, Sepehr N; Phillips, Samuel; Lee, David; Bradshaw, Catriona S; Chen, Marcus Y; Fairley, Christopher K

    2016-10-01

    Neisseria gonorrhoeae can be cultured in the saliva of individuals with pharyngeal gonorrhea. The aim of this study was to quantify the gonococcal bacterial DNA loads in the pharynges and saliva among men who have sex with men (MSM) with untreated pharyngeal gonorrhea. Untreated MSM who tested positive for pharyngeal gonorrhea by culture and returned for antibiotic treatment within 14 days at the Melbourne Sexual Health Centre between October 2014 and March 2015 were eligible for this study. The gonococcal bacterial DNA load was measured using real-time quantitative PCR. The median gonococcal bacterial DNA loads in the pharynges and saliva were calculated and compared to culture positivity using the Mann-Whitney U test. A total of 33 men were included in this study. The median gonococcal bacterial DNA load did not differ between the pharynges in men who were culture positive (2.5 × 10(5) copies/swab) and culture negative (2.9 × 10(4) copies/swab) (P = 0.166) and the saliva (culture positive, 2.2 × 10(5) copies/ml; culture negative, 2.7 × 10(5) copies/ml) (P = 0.499). The bacterial DNA load in the pharynges (P = 0.695) and saliva (P = 0.969) did not differ between who men returned for treatment within 7 days and those who returned 8 to 14 days later. Substantial gonococcal bacterial DNA loads were detected in both saliva and pharynges among MSM with pharyngeal gonorrhea. These findings suggest that gonorrhea can be transmitted via sexual practices involving exposure to saliva, such as oroanal practices (rimming) and saliva use as a lubricant for anal sex. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  6. Innate humoural immunity is related to eggshell bacterial load of European birds: a comparative analysis

    Science.gov (United States)

    Soler, Juan José; Peralta-Sánchez, Juan Manuel; Flensted-Jensen, Einar; Martín-Platero, Antonio Manuel; Møller, Anders Pape

    2011-09-01

    Fitness benefits associated with the development of a costly immune system would include not only self-protection against pathogenic microorganisms but also protection of host offspring if it reduces the probability and the rate of vertical transmission of microorganisms. This possibility predicts a negative relationship between probabilities of vertical transmission of symbionts and level of immune response that we here explore inter-specifically. We estimated eggshell bacterial loads by culturing heterotrophic bacteria, Enterococcus, Staphylococcus and Enterobacteriaceae on the eggshells of 29 species of birds as a proxy of vertical transmission of bacteria from mother to offspring. For this pool of species, we also estimated innate immune response (natural antibody and complement (lysis)) of adults, which constitute the main defence against bacterial infection. Multivariate general linear models revealed the predicted negative association between natural antibodies and density of bacteria on the eggshell of 19 species of birds for which we sampled the eggs in more than one nest. Univariate analyses revealed significant associations for heterotrophic bacteria and for Enterobacteriaceae, a group of bacteria that includes important pathogens of avian embryos. Therefore, these results suggest a possible trans-generational benefit of developing a strong immune system by reducing vertical transmission of pathogens.

  7. Diet and environment shape fecal bacterial microbiota composition and enteric pathogen load of grizzly bears.

    Directory of Open Access Journals (Sweden)

    Clarissa Schwab

    Full Text Available BACKGROUND: Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos and relates these to food resources consumed by bears. METHODOLOGY/PRINCIPAL FINDINGS: Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. CONCLUSION: This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.

  8. Determination of bacterial load in house dust using qPCR, chemical markers and culture.

    Science.gov (United States)

    Kärkkäinen, Päivi M; Valkonen, Maria; Hyvärinen, Anne; Nevalainen, Aino; Rintala, Helena

    2010-03-01

    In this study, we developed two novel qPCR-assays for the detection of bacteria in house dust; one that determines the total bacterial amount and another that detects Gram-positive and Gram-negative bacteria separately. The methods were tested in silico and in vitro with microbial strains and vacuum cleaner dust samples, and validated in relation to culture and chemical marker analysis. We also compared the results of these three types of methods (qPCR, culture and chemical marker analysis) in 211 house dust samples from farming and non-farming environments. Microbial concentrations determined by the new qPCR assays (median 7.2 x 10(5) cell equivalents mg(-1)) were about two orders of magnitude higher than concentrations obtained by culture (median 6.7 x 10(3) cfu mg(-1)). The median concentration of muramic acid was 25.67 ng mg(-1) and that of 3-hydroxy fatty acids, expressed as LPS(10-16) was 26.14 pg mg(-1). Correlations between qPCR and chemical markers were moderate, while correlations between culture and qPCR and chemical markers were low to moderate. All the methods used in this study showed that the microbial concentrations are statistically significantly higher (p < 0.001, Mann-Whitney) in farming than non-farming environments.As a conclusion, all tested methods can be used for determining the bacterial load in dust samples, but none of the methods was superior to the others. The results obtained with these methods represent different aspects of bacterial exposure and therefore the results are not expected to be identical with each other.

  9. High power s-band vacuum load

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, Michael [Muons, Inc., Batavia, IL (United States); Dudas, Alan [Muons, Inc., Batavia, IL (United States); Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-29

    Through a combination of experimentation and calculation the components of a novel room temperature dry load were successfully fabricated. These components included lossy ceramic cylinders of various lengths, thicknesses, and percent of silicon carbide (SiC). The cylinders were then assembled into stainless steel compression rings by differential heating of the parts and a special fixture. Post machining of this assembly provided a means for a final weld. The ring assemblies were then measured for S-parameters, individually and in pairs using a low-cost TE10 rectangular to TE01 circular waveguide adapter specially designed to be part of the final load assembly. Matched pairs of rings were measured for assembly into the final load and a sliding short designed and fabricated to assist in determining the desired short location in the final assembly. The plan for the project was for Muons, Inc. to produce prototype loads for long-term testing at SLAC. The STTR funds for SLAC were to upgrade and operate their test station to ensure that the loads would satisfy their requirements. Phase III was to be the sale to SLAC of loads that Muons, Inc. would manufacture. However, an alternate solution that involved a rebuild of the old loads, reduced SLAC budget projections, and a relaxed time for the replacement of all loads meant that in-house labor will be used to do the upgrade without the need for the loads developed in this project. Consequently, the project was terminated before the long term testing was initiated. However, SLAC can use the upgraded test stand to compare the long-term performance of the ones produced in this project with their rebuilt loads when they are available.

  10. The degradation processes in high loaded casts

    Directory of Open Access Journals (Sweden)

    E. Ďuriníková

    2010-01-01

    Full Text Available In this work are described structural changes of jet engine DV – 2 turbine blades and effect of degradation process. Turbine blades work in aggressively environs and because of that there are rate among high loaded cast stock. As an experimental material we have chose nickel superalloy ŽS6K with surface heat - resisting alitize layer. Evaluation is slant on largeness wearing over work of certain number of hour in operation. Effect working environs and overrun working temperatures is show changes measures as well as changes macrostructure of basic material blades. Evaluate is advance quantitative metallography through the medium metallographic software NIS element. Quantitative analysis evaluate thickness measures, quality control outer look and lack mixture in the seat, which is not splash, is precede by lack of near another applied protective layer. Allowance is knot on last examination in the area ratings protective heat-resisting layers and gives records for others possible ratings and experiments in this area.

  11. Numerical evaluation of tandem rotor for highly loaded transonic fan

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bin; LIU Bao-jie

    2011-01-01

    Transonic tandem rotor was designed for highly loaded fan at a corrected tip speed of 381 m/s and another conventional rotor was designed as a baseline to evaluate the loading superiority of tandem rotor with three-dimensional (3-D) numerical simulation. The aft blade solidity and its impact on total loading level were studied in depth. The result indicates that tandem rotor has potential to achieve higher loading level and attain favorable aerodynamic performance in a wide range of loading coefficient 0. 55 ~ 0.68, comparing with the conventional rotor which produced a total pressure ratio of 2.0 and loading coefficient of 0. 42.

  12. High prevalence of biofilm synergy among bacterial soil isolates in cocultures indicates bacterial interspecific cooperation

    DEFF Research Database (Denmark)

    Ren, Dawei; Madsen, Jonas Stenløkke; Sørensen, Søren Johannes;

    2015-01-01

    of single-species biofilms, indicating that all the individual strains benefit from inclusion in the multispecies community. Our results show a high prevalence of synergy in biofilm formation in multispecies consortia isolated from a natural bacterial habitat and suggest that interspecific cooperation...

  13. Polybiguanide (PHMB) loaded in PLA scaffolds displaying high hydrophobic, biocompatibility and antibacterial properties

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, Elena; Calderón, Silvia [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Valle, Luis J. del, E-mail: luis.javier.del.valle@upc.edu [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, Jordi [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CrNE), Universitat Politècnica de Catalunya, Edifici C, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain)

    2015-05-01

    Polyhexamethylenebiguanide hydrochloride (PHMB), a low molecular weight polymer related to chlorohexidine (CHX), is a well-known antibacterial agent. In this study, polylactide (PLA) nanofibers loaded with PHMB were produced by electrospinning to obtain 3D biodegradable scaffolds with antibacterial properties. PLA fibers loaded with CHX were used as control. The electrospun fibers were studied and analyzed by SEM, FTIR, DSC and contact angle measurements. PHMB and CHX release from loaded scaffolds was evaluated, as well as their antibacterial activity and biocompatibility. The results showed that the nanofibers became smoother and their diameter smaller with increasing the amount of loaded PHMB. This feature led to an increase of both surface roughness and hydrophobicity of the scaffold. PHMB release was highly dependent on the hydrophilicity of the medium and differed from that determined for CHX. Lastly, PHMB-loaded PLA scaffolds showed antibacterial properties since they inhibited adhesion and bacterial growth, and exhibited biocompatible characteristics for the adhesion and proliferation of both fibroblast and epithelial cell lines. - Highlights: • Nanofibers of PLA-PHMB (antibacterial polymer) were prepared by electrospinning. • PHMB has hydrophilic character but the PLA-PHMB scaffolds were highly hydrophobic. • The high-hydrophobicity of the new scaffolds conditioned the release of PHMB. • The controlled release of PHMB inhibited the growth and bacterial adhesion. • PLA-PHMB scaffolds have biocompatibility with fibroblast and epithelial cells.

  14. Tuberculous Pericarditis is Multibacillary and Bacterial Burden Drives High Mortality

    Directory of Open Access Journals (Sweden)

    Jotam G. Pasipanodya

    2015-11-01

    Interpretation: Patients with culture confirmed tuberculous pericarditis have a high bacillary burden, and this bacterial burden drives mortality. Thus proven tuberculosis pericarditis is not a paucibacillary disease. Moreover, the severe immunosuppression suggests limited inflammation. There is a need for the design of a highly bactericidal regimen for this condition.

  15. Cognitive skills and bacterial load: comparative evidence of costs of cognitive proficiency in birds

    Science.gov (United States)

    Soler, Juan José; Peralta-Sánchez, Juan Manuel; Martín-Vivaldi, Manuel; Martín-Platero, Antonio Manuel; Flensted-Jensen, Einar; Møller, Anders Pape

    2012-02-01

    Parasite-mediated selection may affect the evolution of cognitive abilities because parasites may influence development of the brain, but also learning capacity. Here, we tested some predictions of this hypothesis by analyzing the relationship between complex behaviours (feeding innovations (as a measure of behavioural flexibility) and ability to detect foreign eggs in their nests (i.e. a measure of discriminatory ability)) and abundance of microorganisms in different species of birds. A positive relationship would be predicted if these cognitive abilities implied a larger number of visited environments, while if these skills favoured detection and avoidance of risky environments, a negative relationship would be the prediction. Bacterial loads of eggshells, estimated for mesophilic and potentially pathogenic bacteria (i.e. Enterococcus, Staphylococcus and Enterobacteriaceae), were used as a surrogate of probability of contact with pathogenic bacteria. We found that bird species with higher feeding innovation rates and rejection rates of experimental brood parasitic eggs had higher density of bacteria on their eggshells than the average species. Since the analysed groups of microorganisms include pathogenic bacteria, these results suggest that both feeding innovation and ability to recognize foreign eggs are costly and highlight the importance of parasite-mediated selection in explaining the evolution of cognitive abilities in animals.

  16. Effectiveness of oxytetracycline in reducing the bacterial load in rohu fish (Labeo rohita, Hamilton) under laboratory culture condition

    Institute of Scientific and Technical Information of China (English)

    Syed Ariful Haque; Md Shaheed Reza; Md Rajib Sharker; Md Mokhlasur Rahman; Md Ariful Islam

    2014-01-01

    Objective: To observe the effectiveness of most widely used antibiotic, oxytetracycline (OTC) in reducing the bacterial load in rohu fish under artificial culture condition in the laboratory.Methods:University, Mymensingh-2202. The fish were reared in 8 aquaria where fish in 5 aquaria were used for replication of the treatment (experimental group) and fish in remaining 3 aquaria were considered as a control (Control group). OTC was fed to the fish in the experimental aquarium at the rate of 2 g/kg through diet twice daily whereas fish reared under control condition was given feed without antibiotic for 20 d and bacterial content in the aquarium water, gills, skin and intestine of fish were estimated at every alternative day after onset of the experiment. The experiment was conducted in the Faculty Fisheries, Bangladesh Agricultural Results: Rearing the fish with OTC treated feed resulted in gradual decrease of bacterial load in the aquarium water, gills, intestine and skin of the fish whereas the content remain unchanged or little increased in the control group. Water quality parameters such as dissolved oxygen, pH and total hardness were within the suitable range in the experimental aquarium but not in control aquaria throughout the experimental period.Conclusions:bacterial load in fish and can be used commercially for maintaining the fish health in aquarium conditions. These results suggest that OTC could be a potential antibiotic to reduce the

  17. Biodegradation and kinetics of aerobic granules under high organic loading rates in sequencing batch reactor.

    Science.gov (United States)

    Chen, Yao; Jiang, Wenju; Liang, David Tee; Tay, Joo Hwa

    2008-05-01

    Biodegradation, kinetics, and microbial diversity of aerobic granules were investigated under a high range of organic loading rate 6.0 to 12.0 kg chemical oxygen demand (COD) m(-3) day(-1) in a sequencing batch reactor. The selection and enriching of different bacterial species under different organic loading rates had an important effect on the characteristics and performance of the mature aerobic granules and caused the difference on granular biodegradation and kinetic behaviors. Good granular characteristics and performance were presented at steady state under various organic loading rates. Larger and denser aerobic granules were developed and stabilized at relatively higher organic loading rates with decreased bioactivity in terms of specific oxygen utilization rate and specific growth rate (muoverall) or solid retention time. The decrease of bioactivity was helpful to maintain granule stability under high organic loading rates and improve reactor operation. The corresponding biokinetic coefficients of endogenous decay rate (kd), observed yield (Yobs), and theoretical yield (Y) were measured and calculated in this study. As the increase of organic loading rate, a decreased net sludge production (Yobs) is associated with an increased solid retention time, while kd and Y changed insignificantly and can be regarded as constants under different organic loading rates.

  18. Low reflectance high power RF load

    Energy Technology Data Exchange (ETDEWEB)

    Ives, R. Lawrence; Mizuhara, Yosuke M.

    2016-02-02

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  19. Application of PSO, Artificial Bee Colony and Bacterial Foraging Optimization algorithms to economic load dispatch: An analysis

    CERN Document Server

    Baijal, Anant; Jayabarathi, T

    2011-01-01

    This paper illustrates successful implementation of three evolutionary algorithms, namely- Particle Swarm Optimization(PSO), Artificial Bee Colony (ABC) and Bacterial Foraging Optimization (BFO) algorithms to economic load dispatch problem (ELD). Power output of each generating unit and optimum fuel cost obtained using all three algorithms have been compared. The results obtained show that ABC and BFO algorithms converge to optimal fuel cost with reduced computational time when compared to PSO for the two example problems considered.

  20. Cementitious Stabilization of Mixed Wastes with High Salt Loadings

    Energy Technology Data Exchange (ETDEWEB)

    Spence, R.D.; Burgess, M.W.; Fedorov, V.V.; Downing, D.J.

    1999-04-01

    Salt loadings approaching 50 wt % were tolerated in cementitious waste forms that still met leach and strength criteria, addressing a Technology Deficiency of low salt loadings previously identified by the Mixed Waste Focus Area. A statistical design quantified the effect of different stabilizing ingredients and salt loading on performance at lower loadings, allowing selection of the more effective ingredients for studying the higher salt loadings. In general, the final waste form needed to consist of 25 wt % of the dry stabilizing ingredients to meet the criteria used and 25 wt % water to form a workable paste, leaving 50 wt % for waste solids. The salt loading depends on the salt content of the waste solids but could be as high as 50 wt % if all the waste solids are salt.

  1. High-Frequency Axial Fatigue Test Procedures for Spectrum Loading

    Science.gov (United States)

    2016-07-20

    REPORT NO: NAWCADPAX/TIM-2016/49 HIGH - FREQUENCY AXIAL FATIGUE TEST PROCEEDURES FOR SPECTRUM LOADING by David T. Rusk, AIR...OF THE NAVY NAVAL AIR WARFARE CENTER AIRCRAFT DIVISION PATUXENT RIVER, MARYLAND NAWCADPAX/TIM-2016/49 20 July 2016 HIGH - FREQUENCY AXIAL...Technical Information Memorandum 3. DATES COVERED 4. TITLE AND SUBTITLE High - Frequency Axial Fatigue Test Procedures for Spectrum Loading

  2. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  3. High-Temperature, High-Load-Capacity Radial Magnetic Bearing

    Science.gov (United States)

    Provenza, Andrew; Montague, Gerald; Kascak, Albert; Palazzolo, Alan; Jansen, Ralph; Jansen, Mark; Ebihara, Ben

    2005-01-01

    A radial heteropolar magnetic bearing capable of operating at a temperature as high as 1,000 F (=540 C) has been developed. This is a prototype of bearings for use in gas turbine engines operating at temperatures and speeds much higher than can be withstood by lubricated rolling-element bearings. It is possible to increase the maximum allowable operating temperatures and speeds of rolling-element bearings by use of cooling-air systems, sophisticated lubrication systems, and rotor-vibration- damping systems that are subsystems of the lubrication systems, but such systems and subsystems are troublesome. In contrast, a properly designed radial magnetic bearing can suspend a rotor without contact, and, hence, without need for lubrication or for cooling. Moreover, a magnetic bearing eliminates the need for a separate damping system, inasmuch as a damping function is typically an integral part of the design of the control system of a magnetic bearing. The present high-temperature radial heteropolar magnetic bearing has a unique combination of four features that contribute to its suitability for the intended application: 1. The wires in its electromagnet coils are covered with an insulating material that does not undergo dielectric breakdown at high temperature and is pliable enough to enable the winding of the wires to small radii. 2. The processes used in winding and potting of the coils yields a packing factor close to 0.7 . a relatively high value that helps in maximizing the magnetic fields generated by the coils for a given supplied current. These processes also make the coils structurally robust. 3. The electromagnets are of a modular C-core design that enables replacement of components and semiautomated winding of coils. 4. The stator is mounted in such a manner as to provide stable support under radial and axial thermal expansion and under a load as large as 1,000 lb (.4.4 kN).

  4. Mesoporous TiO2 implants for loading high dosage of antibacterial agent

    Science.gov (United States)

    Park, Se Woong; Lee, Donghyun; Choi, Yong Suk; Jeon, Hoon Bong; Lee, Chang-Hoon; Moon, Ji-Hoi; Kwon, Il Keun

    2014-06-01

    We have fabricated mesoporous thin films composed of TiO2 nanoparticles on anodized titanium implant surfaces for loading drugs at high doses. Surface anodization followed by treatment with TiO2 paste leads to the formation of mechanically stable mesoporous thin films with controllable thickness. A series of antibacterial agents (silver nanoparticles, cephalothin, minocycline, and amoxicillin) were loaded into the mesoporous thin films and their antibacterial activities were evaluated against five bacterial species including three oral pathogens. Additionally, two agents (silver nanoparticles and minocycline) were loaded together on the thin film and tested for antibacterial effectiveness. The combination of silver nanoparticles and minocycline was found to display a wide range of effectiveness against all tested bacteria.

  5. Energy efficiency indicators for high electric-load buildings

    Energy Technology Data Exchange (ETDEWEB)

    Aebischer, Bernard; Balmer, Markus A.; Kinney, Satkartar; Le Strat, Pascale; Shibata, Yoshiaki; Varone, Frederic

    2003-06-01

    Energy per unit of floor area is not an adequate indicator for energy efficiency in high electric-load buildings. For two activities, restaurants and computer centres, alternative indicators for energy efficiency are discussed.

  6. Bacterial ghosts as novel advanced drug delivery systems: antiproliferative activity of loaded doxorubicin in human Caco-2 cells.

    Science.gov (United States)

    Paukner, Susanne; Kohl, Gudrun; Lubitz, Werner

    2004-01-08

    Systemic application of anticancer drugs often causes severe toxic side effects. To reduce the undesired effects, advanced drug delivery systems are needed which are based on specific cell targeting vehicles. In this study, bacterial ghosts from Mannheimia haemolytica were used for site-specific delivery of doxorubicin (DOX) to human colorectal adenocarcinoma cells (Caco-2). Bacterial ghosts are non-denatured envelopes of Gram-negative bacteria with fully intact surface structures for specific attachment to mammalian cells. The in vitro release profile of DOX-ghosts demonstrated that the loaded drug was non-covalently associated with the bacterial ghosts and that the drug delivery vehicles themselves represent a slow release system. Adherence studies showed that the M. haemolytica ghosts more efficiently than E. coli ghosts targeted the Caco-2 cells and released the loaded DOX within the cells. Cytotoxicity assays revealed that the DOX-ghosts exhibited potent antiproliferative activities on Caco-2 cells as the DOX associated with ghosts was two magnitude of orders more cytotoxic than free DOX provided in the medium at the same concentrations. Notably, a significant reduction in the cell viability was measured with DOX-ghosts at low DOX concentrations, which had no inhibitory effect when applied as free DOX after incubation for 16 h or when applied at higher concentrations for only 10 min to the cells. As the higher antiproliferative effects of DOX on Caco-2 cells were mediated by the specific drug targeting properties of the bacterial ghosts, the bacterial ghost system represents a novel platform for advanced drug delivery.

  7. Organic loading rates affect composition of soil-derived bacterial communities during continuous, fermentative biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yonghua; Bruns, Mary Ann [Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Husen; Salerno, Michael; Logan, Bruce E. [Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2008-11-15

    Bacterial community composition during steady-state, fermentative H{sub 2} production was compared across a range of organic loading rates (OLRs) of 0.5-19 g COD l{sup -1} h{sup -1} in a 2-l continuous flow reactor at 30 C. The varied OLRs were achieved with glucose concentrations of 2.5-10 g l{sup -1} and hydraulic retention times of 1-10 h. The synthetic wastewater feed was amended with L-cysteine and maintained at a pH of 5.5. For each run at a given glucose concentration, the reactor was inoculated with an aliquot of well-mixed agricultural topsoil that had been heat-treated to reduce numbers of vegetative cells. At OLRs less than 2 g COD l{sup -1} h{sup -1}, DNA sequences from ribosomal RNA intergenic spacer analysis profiles revealed more diverse and variable populations (Selenomonas, Enterobacter, and Clostridium spp.) than were observed above 2 g COD l{sup -1} h{sup -1} (Clostridium spp. only). An isolate, LYH1, was cultured from a reactor sample (10 g glucose l{sup -1} at a 10-h HRT) on medium containing L-cysteine. In confirming H{sub 2} production by LYH1 in liquid batch culture, lag periods for H{sub 2} production in the presence and absence of L-cysteine were 5 and 50 h, respectively. The 16S rRNA gene sequence of LYH1 indicated that the isolate was a Clostridium sp. affiliated with RNA subcluster Ic, with >99% similarity to Clostridium sp. FRB1. In fluorescent in situ hybridization tests, an oligonucleotide probe complementary to the 16S rRNA of LYH1 hybridized with 90% of cells observed at an OLR of 2 g COD h{sup -1}, compared to 26% of cells at an OLR of 0.5 g COD l{sup -1} h{sup -1}. An OLR of 2 g COD l{sup -1} h{sup -1} appeared to be a critical threshold above which clostridia were better able to outcompete Enterobacteriaceae and other organisms in the mixed soil inoculum. Our results are discussed in light of other biohydrogen studies employing pure cultures and mixed inocula. (author)

  8. The effect of pomegranate extract on survival and peritoneal bacterial load in cecal ligation and perforation model of sepsis in rats

    Directory of Open Access Journals (Sweden)

    Sanaz Tavasoli

    2014-01-01

    Conclusions: Our study demonstrates for the first time that pomegranate extract could increase mortality rate via increasing peritoneal cavity bacterial load, in CLP sepsis model. More studies to assess mechanisms of this effect are warranted.

  9. High resolution FESEM and TEM reveal bacterial spore attachment.

    Science.gov (United States)

    Panessa-Warren, Barbara J; Tortora, George T; Warren, John B

    2007-08-01

    Transmission electron microscopy (TEM) studies in the 1960s and early 1970s using conventional thin section and freeze fracture methodologies revealed ultrastructural bacterial spore appendages. However, the limited technology at that time necessitated the time-consuming process of imaging serial sections and reconstructing each structure. Consequently, the distribution and function of these appendages and their possible role in colonization or pathogenesis remained unknown. By combining high resolution field emission electron microscopy with TEM images of identical bacterial spore preparations, we have been able to obtain images of intact and sectioned Bacillus and Clostridial spores to clearly visualize the appearance, distribution, resistance (to trypsin, chloramphenicol, and heat), and participation of these structures to facilitate attachment of the spores to glass, agar, and human cell substrates. Current user-friendly commercial field emission scanning electron microscopes (FESEMs), permit high resolution imaging, with high brightness guns at lower accelerating voltages for beam sensitive intact biological samples, providing surface images at TEM magnifications for making direct comparisons. For the first time, attachment structures used by pathogenic, environmental, and thermophile bacterial spores could be readily visualized on intact spores to reveal how specific appendages and outer spore coats participated in spore attachment, colonization, and invasion.

  10. Part-load performance of a high temperature Kalina cycle

    DEFF Research Database (Denmark)

    Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl

    2015-01-01

    bottoming cycle, and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve...... the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated...... by changing the solar heat input to the receiver. Compared with the steam Rankine cycle, the Kalina cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the cycle. The results include the part-load curves...

  11. Microbial response and elimination capacity in biofilters subjected to high toluene loadings.

    Science.gov (United States)

    Song, JiHyeon; Kinney, Kerry A

    2005-09-01

    Elimination capacity (EC) is frequently used as a performance and design criterion for vapor-phase biofilters without further verification of the microbial quantity and activity. This study was conducted to investigate how biofilters respond to high pollutant loadings and ultimately how this affects the EC of the biofilter. Two identical laboratory-scale biofilters were maintained at an initial toluene loading rate of 46 g m-3 h-1 for a period of 24 days. After the initial biofilm development stage, the loading rates were increased to 91 g m-3 h-1 and 137 g m-3 h-1, respectively. Following a short period of pseudo-steady state, toluene removal efficiencies rapidly declined in both biofilters, with a concurrent decline in both critical and maximum ECs. The decline was mainly due to deterioration in the biodegradation activity of the biofilm and a decline in the toluene-degrading bacterial population within the biofilm phase. The findings imply that high toluene loadings accelerated the deterioration in overall performance due to a rapid accumulation of inactive biomass. As a result, care must be used when relying on EC values for biofilter design and operational purposes, since the values do not appropriately reflect the temporal changes in biodegradation activity and active biomass quantities that can occur in biofilters subjected to high inlet loadings.

  12. Automatic imitation? Imitative compatibility affects responses at high perceptual load.

    Science.gov (United States)

    Catmur, Caroline

    2016-04-01

    Imitation involves matching the visual representation of another's action onto the observer's own motor program for that action. However, there has been some debate regarding the extent to which imitation is "automatic"-that is, occurs without attention. Participants performed a perceptual load task in which images of finger movements were presented as distractors. Responses to target letter stimuli were performed via finger movements that could be imitatively compatible (requiring the same finger movement) or incompatible with the distractor movements: In this common stimulus-response compatibility manipulation, the stimulus set comprises images of the response movements, producing an imitative compatibility effect. Attention to the distractor movements was manipulated by altering perceptual load through increasing the number of nontarget letter stimuli. If imitation requires attention, then at high perceptual load, imitative compatibility should not affect response times. In contrast, imitative compatibility influenced response times at high perceptual load, demonstrating that distractor movements were processed. However, the compatibility effect was reversed, suggesting that longer response times at high perceptual load tap into an inhibitory stage of distractor movement processing. A follow-up experiment manipulating temporal delay between targets and distractor movements supported this explanation. Further experiments confirmed that nonmovement distractor stimuli in the same configuration produced standard perceptual load effects and that results were not solely due to effector compatibility. These data suggest that imitation can occur without attention. (PsycINFO Database Record

  13. Influence of load by high power on the optical coupler

    Science.gov (United States)

    Bednarek, Lukas; Poboril, Radek; Vanderka, Ales; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

    2016-12-01

    Nowadays, aging of the optical components is a very current topic. Therefore, some investigations are focused on this area, so that the aging of the optical components is accelerated by thermal, high power and gamma load. This paper deals by findings of the influence of the load by laser with high optical power on the transmission parameters of the optical coupler. The investigated coupler has one input and eight outputs (1x8). Load by laser with high optical power is realized using a fiber laser with a cascade configuration EDFA amplifiers. The output power of the amplifier is approximately 250 mW. Duration of the load is moving from 104 hours to 139 hours. After each load, input power and output powers of all branches are measured. Following parameters of the optical coupler are calculated using formulas: the insertion losses of the individual branches, split ratio, total losses, homogeneity of the losses and cross-talk between different branches. All measurements are performed at wavelengths 1310 nm and 1550 nm. Individual optical powers are measured 20 times, due to the exclusion of statistical error of the measurement. After measuring, the coupler is connected to the amplifier for next cycle of the load. The paper contains an evaluation of the results of the coupler before and after four cycles of the burden.

  14. Micro-machined high capacity silicon load cells

    NARCIS (Netherlands)

    Zwijze, A.F.

    2000-01-01

    The aim of the research presented in this thesis is to improve the performance of high capacity conventional load cells or force sensors by using silicon as the base material. Silicon is used because it offers the possibility of realising small, light, low cost and high performance mechanical sensor

  15. The effect and mechanism of action of carbocysteine on airway bacterial load in rats chronically exposed to cigarette smoke.

    Science.gov (United States)

    Sun, Li; Tang, Lifeng; Xu, Yan; Wang, Shouqin; Li, Yaming; Kang, Jian

    2010-10-01

    Carbocysteine (S-carboxymethylcysteine) is a mucoactive drug with in vitro free radical scavenging and anti-inflammatory properties. Several clinical trials have indicated that carbocysteine reduces exacerbation rates in COPD. In the present study, the effect of carbocysteine on the airway load of Haemophilus influenzae was assessed in rats chronically exposed to cigarette smoke (CS). In addition, the effects of carbocysteine on airway mucus hypersecretion and mucociliary clearance (MCC) associated with the adherence and clearance of H. influenzae were investigated. Wistar rats were randomly divided into control, carbocysteine vehicle, CS exposure and carbocysteine treatment groups. After 12 weeks, rats were selected for quantitative inoculation of H. influenzae. BAL fluid and lungs were collected aseptically after 3 h for quantitative culture of H. influenzae. MCC was measured by quantifying the clearance of (99m)Tc-Sc. Goblet cell metaplasia and the presence of mucoid matter were evaluated by Alcian blue/periodic acid-Schiff staining. Mucin 5AC (Muc5AC) expression was detected by western blotting and real-time reverse transcription-PCR. Exposure to CS increased airway H. influenzae load, aggravated mucus hypersecretion and delayed MCC. Treatment with carbocysteine decreased airway H. influenzae load, and attenuated airway mucus hypersecretion, with improved MCC associated with adherence and clearance of H. influenzae. These results suggest that carbocysteine may be beneficial in patients with COPD by increasing the clearance of bacteria and decreasing bacterial load. © 2010 The Authors. Respirology © 2010 Asian Pacific Society of Respirology.

  16. Least Squares-support Vector Machine Load Forecasting Approach Optimized by Bacterial Colony Chemotaxis Method

    Institute of Scientific and Technical Information of China (English)

    ZENG Ming; LU Chunquan; TIAN Kuo; XUE Song

    2011-01-01

    During the Twelfth Five-Year plan, large-scale construction of smart grid with safe and stable operation requires a timely and accurate short-term load forecasting method. Moreover, along with the full-scale smart grid construction, the power supply mode and consumption mode of the whole system can be optimized through the accurate short-term load forecasting; and the security, stability and cleanness of the system can be guaranteed.

  17. Assembly and Mechanical Properties of the Cargo-Free and Cargo-Loaded Bacterial Nanocompartment Encapsulin

    NARCIS (Netherlands)

    Snijder, Joost; Kononova, Olga; Barbu, Ioana M; Uetrecht, Charlotte; Rurup, W Frederik; Koay, Melissa S T; Burnley, Rebecca J; Cornelissen, Jeroen J L M; Roos, Wouter H; Barsegov, Valeri; Wuite, Gijs J L; Heck, Albert J R

    2016-01-01

    Prokaryotes mostly lack membranous compartments that are typical of eukaryotic cells, but instead, they have various protein-based organelles. These include bacterial microcompartments like the carboxysome and the virus-like nanocompartment encapsulin. Encapsulins have an adaptable mechanism for enz

  18. Assembly and mechanical properties of the cargo-free and cargo-loaded bacterial nanocompartment encapsulin

    NARCIS (Netherlands)

    Snijder, Joost; Kononova, Olga; Barbu, Ioana M; Uetrecht, Charlotte; Rurup, W Frederik; Burnley, Rebecca J; Koay, Melissa S T; Cornelissen, Jeroen J L M; Roos, Wouter H; Barsegov, Valeri; Wuite, Gijs J L; Heck, Albert J R

    2016-01-01

    Prokaryotes mostly lack membranous compartments that are typical of eukaryotic cells, but instead they have various protein-based organelles. These include bacterial microcompartments like the carboxysome and the virus-like nanocompartment encapsulin. Encapsulins have an adaptable mechanism for enzy

  19. The relation between oral Candida load and bacterial microbiome profiles in Dutch older adults

    NARCIS (Netherlands)

    Kraneveld, E.A.; Buijs, M.J.; Bonder, M.J.; Visser, M.; Keijser, B.J.F.; Crielaard, W.; Zaura, E.

    2012-01-01

    Currently there are no evidence-based ecological measures for prevention of overgrowth and subsequent infection by fungi in the oral cavity. The aim of this study was to increase our knowledge on fungal-bacterial ecological interactions. Salivary Candida abundance of 82 Dutch adults aged 58-80 years

  20. The relation between oral candida load and bacterial microbiome profiles in dutch older adults

    NARCIS (Netherlands)

    Kraneveld, E.A.; Buijs, M.J.; Bonder, M.J.; Visser, M.; Keijser, B.J.F.; Crielaard, W.; Zaura, E.

    2012-01-01

    Currently there are no evidence-based ecological measures for prevention of overgrowth and subsequent infection by fungi in the oral cavity. The aim of this study was to increase our knowledge on fungal-bacterial ecological interactions. Salivary Candida abundance of 82 Dutch adults aged 58-80 years

  1. Relation of sputum colour to bacterial load in acute exacerbations of COPD

    NARCIS (Netherlands)

    Brusse-Keizer, M. G. J.; Grotenhuis, A. J.; Kerstjens, H. A. M.; Telgen, M. C.; van der Palen, J.; Hendrix, M. G. R.; van der Valk, P. D. L. P. M.

    2009-01-01

    Background: When COPI) patients present with an exacerbation, one cannot verify a bacterial. cause of an exacerbation without time-consuming laboratory analyses. This makes it difficult to decide up front if antibiotic treatment is needed. Therefore, in clinical, practice sputum colour and purulence

  2. Total Antioxidant Capacity and Total Oxidant Status in Saliva of Periodontitis Patients in Relation to Bacterial Load.

    Science.gov (United States)

    Zhang, Taowen; Andrukhov, Oleh; Haririan, Hady; Müller-Kern, Michael; Liu, Shutai; Liu, Zhonghao; Rausch-Fan, Xiaohui

    2015-01-01

    The detection of salivary biomarkers has a potential application in early diagnosis and monitoring of periodontal inflammation. However, searching sensitive salivary biomarkers for periodontitis is still ongoing. Oxidative stress is supposed to play an important role in periodontitis progression and tissue destruction. In this cross-sectional study, we investigated total antioxidant capacity (TAC) and total oxidant status (TOS) in saliva of periodontitis patients compared to healthy controls and their relationship with periodontopathic bacteria and periodontal disease severity. Unstimulated saliva was collected from 45 patients with generalized severe periodontitis and 37 healthy individuals and the TAC/TOS were measured. In addition, salivary levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum in saliva were measured. Salivary TAC was lower in periodontitis patients compared to healthy controls. Moreover, a significant negative correlation of salivary TAC with clinical attachment loss was observed in periodontitis patients. No significant difference in the salivary TOS was observed between periodontitis patients and healthy controls. Bacterial load was enhanced in periodontitis patients and exhibited correlation with periodontal disease severity but not with salivary TAC/TOS. Our data suggest that changes in antioxidant capacity in periodontitis patients are not associated with increased bacterial load and are probably due to a dysregulated immune response.

  3. Total antioxidant capacity and total oxidant status in saliva of periodontitis patients in relation to bacterial load

    Directory of Open Access Journals (Sweden)

    Taowen eZhang

    2016-01-01

    Full Text Available The detection of salivary biomarkers has a potential application in early diagnosis and monitoring of periodontal inflammation. However, searching sensitive salivary biomarkers for periodontitis is still ongoing. Oxidative stress is supposed to play an important role in periodontitis progression and tissue destruction. In this cross-sectional study, we investigated total antioxidant capacity (TAC and total oxidant status (TOS in saliva of periodontitis patients compared to healthy controls and their relationship with periodontopathic bacteria and periodontal disease severity. Unstimulated saliva was collected from 45 patients with generalized severe periodontitis and 37 healthy individuals and the TAC/TOS were measured. In addition, salivary levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum in saliva were measured. Salivary TAC was lower in periodontitis patients compared to healthy controls. Moreover, a significant negative correlation of salivary TAC with clinical attachment loss was observed in periodontitis patients. No significant difference in the salivary TOS was observed between periodontitis patients and healthy controls. Bacterial load was enhanced in periodontitis patients and exhibited correlation with periodontal disease severity but not with salivary TAC/TOS. Our data suggest that changes in antioxidant capacity in periodontitis patients are not associated with increased bacterial load and are probably due to a dysregulated immune response.

  4. A model for damage load and its implications for the evolution of bacterial aging.

    Directory of Open Access Journals (Sweden)

    Lin Chao

    2010-08-01

    Full Text Available Deleterious mutations appearing in a population increase in frequency until stopped by natural selection. The ensuing equilibrium creates a stable frequency of deleterious mutations or the mutational load. Here I develop the comparable concept of a damage load, which is caused by harmful non-heritable changes to the phenotype. A damage load also ensues when the increase of damage is opposed by selection. The presence of a damage load favors the evolution of asymmetrical transmission of damage by a mother to her daughters. The asymmetry is beneficial because it increases fitness variance, but it also leads to aging or senescence. A mathematical model based on microbes reveals that a cell lineage dividing symmetrically is immortal if lifetime damage rates do not exceed a threshold. The evolution of asymmetry allows the lineage to persist above the threshold, but the lineage becomes mortal. In microbes with low genomic mutation rates, it is likely that the damage load is much greater than the mutational load. In metazoans with higher genomic mutation rates, the damage and the mutational load could be of the same magnitude. A fit of the model to experimental data shows that Escherichia coli cells experience a damage rate that is below the threshold and are immortal under the conditions examined. The model estimates the asymmetry level of E. coli to be low but sufficient for persisting at higher damage rates. The model also predicts that increasing asymmetry results in diminishing fitness returns, which may explain why the bacterium has not evolved higher asymmetry.

  5. The effect of high load training on psychomotor speed

    NARCIS (Netherlands)

    Nederhof, E.; Lemmink, K.; Zwerver, J.; Mulder, T.

    The purpose of the present study was to investigate whether overreached athletes show psychomotor slowness after a period of high load training. Fourteen well-trained cyclists (10 male, 4 female, mean age 25.3 [SD = 4.1] years, mean maximal oxygen consumption 65.5 [SD=8.1] ml/ kg-min) performed a

  6. High resolution imaging of surface patterns of single bacterial cells

    Energy Technology Data Exchange (ETDEWEB)

    Greif, Dominik; Wesner, Daniel [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany); Regtmeier, Jan, E-mail: jan.regtmeier@physik.uni-bielefeld.de [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany); Anselmetti, Dario [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany)

    2010-09-15

    We systematically studied the origin of surface patterns observed on single Sinorhizobium meliloti bacterial cells by comparing the complementary techniques atomic force microscopy (AFM) and scanning electron microscopy (SEM). Conditions ranged from living bacteria in liquid to fixed bacteria in high vacuum. Stepwise, we applied different sample modifications (fixation, drying, metal coating, etc.) and characterized the observed surface patterns. A detailed analysis revealed that the surface structure with wrinkled protrusions in SEM images were not generated de novo but most likely evolved from similar and naturally present structures on the surface of living bacteria. The influence of osmotic stress to the surface structure of living cells was evaluated and also the contribution of exopolysaccharide and lipopolysaccharide (LPS) by imaging two mutant strains of the bacterium under native conditions. AFM images of living bacteria in culture medium exhibited surface structures of the size of single proteins emphasizing the usefulness of AFM for high resolution cell imaging.

  7. Effect of High Pressure and Heat on Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Dirk Margosch

    2005-01-01

    Full Text Available Even though the inactivation of microorganisms by high pressure treatment is a subject of intense investigations, the effect of high pressure on bacterial toxins has not been studied so far. In this study, the influence of combined pressure/temperature treatment (0.1 to 800 MPa and 5 to 121 °C on bacterial enterotoxins was determined. Therefore, heat-stable enterotoxin (STa of cholera toxin (CT from Vibrio cholerae, staphylococcal enterotoxins A-E, haemolysin BL (HBL from Bacillus cereus, and Escherichia coli (STa were subjected to different treatment schemes. Structural alterations were monitored in enzyme immunoassays (EIAs. Cytotoxicity of the pressure treated supernatant of toxigenic B. cereus DSM 4384 was investigated with Vero cells. High pressure of 200 to 800 MPa at 5 °C leads to a slight increase of the reactivity of the STa of E. coli. However, reactivity decreased at 800 MPa and 80 °C to (66±21 % after 30 min and to (44±0.3 % after 128 min. At ambient pressure no decrease in EIA reactivity could be observed after 128 min. Pressurization (0.1 to 800 MPa of heat stable monomeric staphylococcal toxins at 5 and 20 °C showed no effect. A combined heat (80 °C and pressure (0.1 to 800 MPa treatment lead to a decrease in the immuno-reactivity to 20 % of its maximum. For cholera toxin a significant loss in latex agglutination was observable only at 80 °C and 800 MPa for holding times higher than 20 min. Interestingly, the immuno-reactivity of B. cereus HBL toxin increased with the increase of pressure (182 % at 800 MPa, 30 °C, and high pressure showed only minor effects on cytotoxicity to Vero cells. Our results indicate that pressurization can increase inactivation observed by heat treatment, and combined treatments may be effective at lower temperatures and/or shorter incubation time.

  8. A 10-day vacancy period after cleaning and disinfection has no effect on the bacterial load in pig nursery units.

    Science.gov (United States)

    Luyckx, K; Millet, S; Van Weyenberg, S; Herman, L; Heyndrickx, M; Dewulf, J; De Reu, K

    2016-10-19

    Biosecurity measures such as cleaning, disinfection and a vacancy period between production cycles on pig farms are essential to prevent disease outbreaks. No studies have tested the effect of a longer vacancy period on bacterial load in nursery units. The present study evaluated the effect of a 10-day vacancy period in pig nursery units on total aerobic flora, Enterococcus spp., Escherichia coli, faecal coliforms and methicillin resistant Staphylococcus aureus (MRSA). Three vacancy periods of 10 days were monitored, each time applied in 3 units. The microbiological load was measured before disinfection and at 1, 4, 7 and 10 days after disinfection. No significant decrease or increase in E. coli, faecal coliforms, MRSA and Enterococcus spp. was noticed. Total aerobic flora counts were the lowest on day 4 after disinfection (i.e. 4.07 log CFU/625 cm(2)) (P disinfection, drinking nipples were still mostly contaminated with total aerobic flora (i.e. 5.32 log CFU/625 cm(2)) and Enterococcus spp. (i.e. 95 % of the samples were positive) (P disinfection with no extra biosecurity measures has no impact on the environmental load of total aerobic flora, E. coli, faecal coliforms, MRSA and Enterococcus spp..

  9. A Comparison of Increases in Volume Load Over 8 Weeks of Low-Versus High-Load Resistance Training

    OpenAIRE

    Schoenfeld; Ogborn; Contreras,, J. g.; Cappaert; Silva Ribeiro; Alvar; Vigotsky

    2016-01-01

    Background It has been hypothesized that the ability to increase volume load (VL) via a progressive increase in the magnitude of load for a given exercise within a given repetition range could enhance the adaptive response to resistance training. Objectives The purpose of this study was to compare changes in volume load (VL) over eight weeks of resistance training (RT) in high-versus low-load protocols. ...

  10. High functional load inhibits phonological contrast loss: a corpus study.

    Science.gov (United States)

    Wedel, Andrew; Kaplan, Abby; Jackson, Scott

    2013-08-01

    For nearly a century, linguists have suggested that diachronic merger is less likely between phonemes with a high functional load--that is, phonemes that distinguish many words in the language in question. However, limitations in data and computational power have made assessing this hypothesis difficult. Here we present the first larger-scale study of the functional load hypothesis, using data from sound changes in a diverse set of languages. Our results support the functional load hypothesis: phoneme pairs undergoing merger distinguish significantly fewer minimal pairs in the lexicon than unmerged phoneme pairs. Furthermore, we show that higher phoneme probability is positively correlated with merger, but that this effect is stronger for phonemes that distinguish no minimal pairs. Finally, within our dataset we find that minimal pair count and phoneme probability better predict merger than change in system entropy at the lexical or phoneme level.

  11. Atomistic simulations of high strain rate loading of nanocrystals

    Science.gov (United States)

    Bringa, E. M.; Tramontina, D.; Ruestes, C. J.; Tang, Y.; Meyers, M. A.; Gunkelmann, N.; Urbassek, H. M.

    2013-03-01

    Materials loaded at high strain rates can reach extreme temperature and pressure conditions. Most experiments on loading of simple materials use poly crystals, while most atomistic simulations of shock wave loading deal with single crystals, due to the higher computational cost of running polycrystal samples. Of course, atomistic simulations of polycrystals with micron-sized grains are beyond the capabilities of current supercomputers. On the other hand, nanocrystals (nc) with grain sizes below 50 nm can be obtained experimentally and modeled reasonably well at high strain rates, opening the possibility of nearly direct comparison between atomistic molecular dynamics (MD) simulations and experiments using high power lasers. We will discuss MD simulations and links to experiments for nc Cu and Ni, as model f.c.c. solids, and nc Ta and Fe, as model b.c.c. solids. In all cases, the microstructure resulting from loading depends strongly on grain size, strain rate and peak applied pressure. We will also discuss effects related to target porosity in nc's. E.M.B. thanks funding from PICT2008-1325.

  12. Part-load performance of a high temperature Kalina cycle

    DEFF Research Database (Denmark)

    Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl

    2015-01-01

    The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine...... bottoming cycle, and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve...... the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated...

  13. Influence of linear profile modification and loading conditions on the dynamic tooth load and stress of high contact ratio gears

    Science.gov (United States)

    Lee, Chinwai; Lin, Hsiang Hsi; Oswald, Fred B.; Townsend, Dennis P.

    1990-01-01

    A computer simulation for the dynamic response of high-contact-ratio spur gear transmissions is presented. High contact ratio gears have the potential to produce lower dynamic tooth loads and minimum root stress but they can be sensitive to tooth profile errors. The analysis presented examines various profile modifications under realistic loading conditions. The effect of these modifications on the dynamic load (force) between mating gear teeth and the dynamic root stress is presented. Since the contact stress is dependent on the dynamic load, minimizing dynamic loads will also minimize contact stresses. It is shown that the combination of profile modification and the applied load (torque) carried by a gear system has a significant influence on gear dynamics. The ideal modification at one value of applied load will not be the best solution for a different load. High-contact-ratio gears were found to require less modification than standard low-contact-ratio gears. High-contact-ratio gears are more adversely affected by excess modification than by under modification. In addition, the optimal profile modification required to minimize the dynamic load (hence the contact stress) on a gear tooth differs from the optimal modification required to minimize the dynamic root (bending) stress. Computer simulation can help find the design tradeoffs to determine the best profile modification to satisfy the conflicting constraints of minimizing both the load and root stress in gears which must operate over a range of applied loads.

  14. Bacterial reduction of mercury in the high arctic

    DEFF Research Database (Denmark)

    Møller, Annette Klæstrup

    from three snow depths and freshwater only showed a scattered representation of the phyla and genera in comparison to strains identified by culture independent methods. The microbial composition of all arctic sample sites was significantly different, with the two uppermost snow layers being most......, Bacteroidetes, Actinobacteria and Planctomycetes in freshwater. The bacteria identified in this study both included phylotypes commonly found in cold environments as well as rare phylotypes. During the time of sampling atmospheric ozone measurements and total Hg measurements in the snow indicated...... suggested that this may be important in the deeper snow layers. This highlights the importance of microbial mercury transformation in the biogeochemical mercury cycling in the High Arctic. While bacterial Hg reduction by the mercuric reductase, MerA, is widespread in temperate environments, its distribution...

  15. High-speed seatbelt pretensioner loading of the abdomen.

    Science.gov (United States)

    Foster, Craig D; Hardy, Warren N; Yang, King H; King, Albert I; Hashimoto, Syuzo

    2006-11-01

    This study characterizes the response of the human cadaver abdomen to high-speed seatbelt loading using pyrotechnic pretensioners. A test apparatus was developed to deliver symmetric loading to the abdomen using a seatbelt equipped with two low-mass load cells. Eight subjects were tested under worst-case scenario, out-of-position (OOP) conditions. A seatbelt was placed at the level of mid-umbilicus and drawn back along the sides of the specimens, which were seated upright using a fixed-back configuration. Penetration was measured by a laser, which tracked the anterior aspect of the abdomen, and by high-speed video. Additionally, aortic pressure was monitored. Three different pretensioner designs were used, referred to as system A, system B and system C. The B and C systems employed single pretensioners. The A system consisted of two B system pretensioners. The vascular systems of the subjects were perfused. Peak anterior abdominal loads due to the seatbelt ranged from 2.8 kN to 10.1 kN. Peak abdominal penetration ranged from 49 mm to 138 mm. Peak penetration speed ranged from 4.0 m/s to 13.3 m/s. Three cadavers sustained liver injury: one AIS 2, and two AIS 3. Cadaver abdominal response corridors for the A and B system pretensioners are proposed. The results are compared to the data reported by Hardy et al. (2001) and Trosseille et al. (2002).

  16. High Hydrogen Loading of Thin Palladium Wires Through

    CERN Document Server

    Celani, F; Marini, P; Di Stefano, V; Nakamura, M; Pace, S; Vecchione, A; Mancini, A; Tripodi, P; Di Gioacchino, D

    2000-01-01

    A new protocol for the electrolytic loading of hydrogen (H) in thin palladium (Pd) wires has been developed. In order to increase the cathodic overvoltage, which is known to be the main parameter capable to enhance the electrolytic $9 H loading of Pd, the catalytic action of the Pd surface versus H-H recombination has been strongly reduced by precipitation of a thin layer of alkaline-earth carbonates on the cathode. A set of electrolytes has been employed, $9 containing small amounts of hydrochloric or sulphuric acid and strontium or calcium ions. The H loading has been continuously evaluated through ac measurements of the Pd wire resistance. Uncommonly low resistivity values, leading to $9 an estimate of exceptionally high H loading, have been observed. Evidence of the existence of a new phase in the very high H content region of the Pd-H system has been inferred on the basis of the determination of the temperature $9 coefficient of the electrical resistivity. For this purpose a thin layer of Hg was galvanic...

  17. Treatment failure of bacterial vaginosis is not associated with higher loads of Atopobium vaginae and Gardnerella vaginalis.

    Science.gov (United States)

    Ferreira, Carolina Sanitá Tafner; Donders, Gilbert Gerard; Parada, Cristina Maria Garcia de Lima; Tristão, Andrea da Rocha; Fernandes, Thaiz; da Silva, Márcia Guimarães; Marconi, Camila

    2017-08-01

    Cervicovaginal Atopobium vaginae and Gardnerella vaginalis are strongly associated with bacterial vaginosis (BV) and are the main components of vaginal biofilms. The low efficacy of BV treatment with metronidazole may be due to the presence of such biofilms. Thus, the aim of this study was to compare the pretreatment cervicovaginal loads of A. vaginae and G. vaginalis for women who restored normal flora and those who persisted with BV after a full course of oral metronidazole. In this cross-sectional study, 309 reproductive-aged women were recruited in a primary health care service in Botucatu, Brazil. Cervicovaginal samples were tested for genital tract infections, microscopic classification of local microbiota and molecular quantification of A. vaginae and G. vaginalis. All the participants with concurrent cervicovaginal infections (n=64) were excluded. A total of 84 out of 245 (34.3 %) women had BV at enrolment and 43 (51.2 %) of them completed the treatment and returned for follow-up. Evaluation of the vaginal microbiota at follow-up showed that 29 (67.4 %) women restored normal vaginal flora, while 14 (32.6 %) still had BV. The pretreatment loads of G. vaginalis were lower in women with treatment failure (P=0.001) compared to those who successfully restored normal flora. The loads of A. vaginae did not differ between the groups. Although G. vaginalis produces several virulence factors and its loads correlate positively with those of A. vaginae, higher cervicovaginal quantities of these bacteria are not associated with treatment failure of BV after oral metronidazole.

  18. A quantitative swab is a good non-invasive alternative to a quantitative biopsy for quantifying bacterial load in wounds healing by second intention in horses.

    Science.gov (United States)

    Van Hecke, L L; Hermans, K; Haspeslagh, M; Chiers, K; Pint, E; Boyen, F; Martens, A M

    2017-07-01

    The aim of this study was to evaluate different techniques for diagnosing wound infection in wounds healing by second intention in horses and to assess the effect of a vortex and sonication protocol on quantitative bacteriology in specimens with a histologically confirmed biofilm. In 50 wounds healing by second intention, a clinical assessment, a quantitative swab, a semi-quantitative swab, and a swab for cytology were compared to a quantitative tissue biopsy (reference standard). Part of the biopsy specimen was examined histologically for evidence of a biofilm. There was a significant, high correlation (Pquantitative swabs and the quantitative biopsies. The semi-quantitative swabs showed a significant, moderate correlation with the quantitative biopsies (Pquantitative swab is an acceptable non-invasive alternative to a quantitative biopsy for quantifying bacterial load in equine wounds healing by second intention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Total bacterial load within Echinacea purpurea, determined using a new PCR-based quantification method, is correlated with LPS levels and in vitro macrophage activity.

    Science.gov (United States)

    Pugh, Nirmal D; Jackson, Colin R; Pasco, David S

    2013-01-01

    Our previous studies indicate that the majority of in vitro monocyte/macrophage activation exhibited by extracts of Echinacea depends on bacterial components. In the present study, total bacterial load was determined within E. purpurea samples and ranged from 6.4 × 10(6) to 3.3 × 10(8) bacteria/g of dry plant material. To estimate total bacterial load, we developed a PCR-based quantification method that circumvents the problems associated with nonviable/nonculturable cells (which precludes using plate counts) or the coamplification of mitochondrial or chloroplast DNA with the use of universal bacterial primers (which precludes the use of qPCR). Differences in total bacterial load within Echinacea samples were strongly correlated with the activity (NF-κB activation in THP-1 cells) and content of bacterial lipopolysaccharides within extracts of this plant material. These results add to the growing body of evidence that bacteria within Echinacea are the main source of components responsible for enhancing innate immune function. Georg Thieme Verlag KG Stuttgart · New York.

  20. When the most potent combination of antibiotics selects for the greatest bacterial load: the smile-frown transition.

    Directory of Open Access Journals (Sweden)

    Rafael Pena-Miller

    Full Text Available Conventional wisdom holds that the best way to treat infection with antibiotics is to 'hit early and hit hard'. A favoured strategy is to deploy two antibiotics that produce a stronger effect in combination than if either drug were used alone. But are such synergistic combinations necessarily optimal? We combine mathematical modelling, evolution experiments, whole genome sequencing and genetic manipulation of a resistance mechanism to demonstrate that deploying synergistic antibiotics can, in practice, be the worst strategy if bacterial clearance is not achieved after the first treatment phase. As treatment proceeds, it is only to be expected that the strength of antibiotic synergy will diminish as the frequency of drug-resistant bacteria increases. Indeed, antibiotic efficacy decays exponentially in our five-day evolution experiments. However, as the theory of competitive release predicts, drug-resistant bacteria replicate fastest when their drug-susceptible competitors are eliminated by overly-aggressive treatment. Here, synergy exerts such strong selection for resistance that an antagonism consistently emerges by day 1 and the initially most aggressive treatment produces the greatest bacterial load, a fortiori greater than if just one drug were given. Whole genome sequencing reveals that such rapid evolution is the result of the amplification of a genomic region containing four drug-resistance mechanisms, including the acrAB efflux operon. When this operon is deleted in genetically manipulated mutants and the evolution experiment repeated, antagonism fails to emerge in five days and antibiotic synergy is maintained for longer. We therefore conclude that unless super-inhibitory doses are achieved and maintained until the pathogen is successfully cleared, synergistic antibiotics can have the opposite effect to that intended by helping to increase pathogen load where, and when, the drugs are found at sub-inhibitory concentrations.

  1. NASA/GE Highly-Loaded Turbine Research Program

    Science.gov (United States)

    Giel, Paul W.

    2008-01-01

    An overview of the NASA/GE Highly-Loaded Turbine Research Program at the NASA Glenn Research Center is presented. The program is sponsored by the Subsonic Fixed Wing Project of the Fundamental Aeronautics Program. The goals of the turbine research program are presented along with their relationship to the higher-level program goals. Two turbine research programs are described; the highly-loaded, single-stage high pressure turbine (HPT) and the highly loaded low pressure turbine (LPT). The HPT program is centered on an extremely high pressure ratio single-stage turbine with an engine stage pressure ratio of 5.5. It was designed with a 33% increase in stage loading. It has shown performance levels 2 points better than current engines operating at the higher work level. Some advantages of the turbine include reduced weight and parts count. Optimization of the blade shape to reduce shock losses is described. The LPT program utilizes a four-stage low pressure turbine with an integral first stage vane/transition duct strut; counterrotation; low-solidity blading; fully optimized flowpath including vanes, blades, and endwalls; and a fluidically controlled turbine vane frame/exit guide vane. The implementation of the LPT into GE s and NASA s test facilities is described. A description of NASA s Single Spool Turbine Facility that is currently under renovation is given. The new, upgraded facility is compared to its predecessor. Renovation design requirements are outlined. Facility limits on pressures, temperatures, flow rates, rotational speeds, and power absorption are described. The current renovation status is given.

  2. Effect of magnesium peroxide biostimulation of fish feed-loaded marine sediments on changes in the bacterial community.

    Science.gov (United States)

    Santander-De Leon, Sheila Mae S; Okunishi, Suguru; Kihira, Masaki; Nakano, Miyo; Nuñal, Sharon N; Hidaka, Masayasu; Yoshikawa, Takeshi; Maeda, Hiroto

    2013-01-01

    The effect of an oxygen-releasing compound (ORC) magnesium peroxide (MgO(2)) on the changes in the bacterial community in organically polluted sediment of aquaculture farms was tested in a microcosm experiment. The sediment, to which fish feed was added, was treated with 1% or 5% MgO(2). The addition of fish feed induced a highly reduced environment with low redox potential, high total sulfides, and abundance of sulfate-reducing bacteria (SRB) . Although the sediment remained highly reduced at 1% MgO(2), there was a significant reduction of total sulfides, increase of redox potential, and resultant reduction of SRB. The bacterial community clearly changed with the treatments according to denaturing gradient gel electrophoresis (DGGE) analysis of 16S ribosomal RNA gene (16S rDNA) . Aerobes disappeared in the fish feed-added sediment, and some SRB emerged in place of these aerobes. On the other hand, the SRB disappeared in the ORC-amended sediment due to its highly oxic condition. This study revealed the bacterial community in the sediments was affected mainly by the redox potential and resultant sulfides produced by SRB, but total organic carbon and nitrogen were not determinants of the microbial population.

  3. High Heat-Load Slits for the PLS Multipole Wiggler

    CERN Document Server

    Gil, Kyehwan; Kim, Young-Chan; Lee, Heung-Soo; Wha Chung, Chin

    2005-01-01

    The HFMX (High Flux Macromolecular X-ray crystallography) beamline under commissioning at Pohang Accelerator Laboratory uses beam from a multipole wiggler for MAD experiment. Two horizontal and vertical slits relevant to high heat load are installed at its front-end. In order to treat high heat load and to reduce beam scattering, the horizontal slit has two glidcop blocks with 10° of vertical inclination and its tungsten blades defining beam size are bolted on backsides of both blocks. The blocks of the slit are adjusted on fixed slides by two actuating bars, respectively. Water through channels machined along the actuating bars cool down the heat load of both blocks. The vertical slit has the same structure as the horizontal slit except its installation direction and angle of vertical inclination. The installed slits show stable operation performance and no alignment for the blocks is required by virtue of a pair of blocks translating on slides. The cooling performance of two slits is also shown to ...

  4. Behavior of high strength concrete columns under eccentric loads

    Directory of Open Access Journals (Sweden)

    Hany A. Kottb

    2015-04-01

    Full Text Available In recent decades, high strength concrete (HSC has been widely accepted by designers and contractors to be used in concrete structures, especially in high compressive stress elements. The research aims to study the behavior of high strength concrete columns under eccentric compression using experimental and analytical programs. The research is divided into two main parts; the first part is an experimental investigation for ten square columns tested at the Cairo University Concrete Research Laboratory. The main studied parameters were eccentricity of the applied load, column slenderness ratio; and ratios of longitudinal and transverse reinforcement. The second part is analytical analysis using nonlinear finite element program ANSYS11 on nineteen columns (ten tested square columns and nine rectangular section columns to study the effect of the previous parameters on the column ultimate load, mid-height displacement, and column cracking patterns. The analyzed columns revealed a good agreement with the experimental results with an average difference of 16% and 17% for column ultimate load and mid-height displacement respectively. Results showed an excellent agreement for cracking patterns. Predictions of columns capacities using the interaction diagrams based on ACI 318-08 stress block parameters indicated a safe design procedure of HSC columns under eccentric compression, with ACI 318-08 being more conservative for moderate reinforced HSC columns.

  5. Fabrication of interconnected microporous biomaterials with high hydroxyapatite nanoparticle loading

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wei; Yao Donggang [School of Polymer Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Zhang Qingwei; Lelkes, Peter I [School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104 (United States); Zhou, Jack G, E-mail: yao@gatech.ed [Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104 (United States)

    2010-09-15

    Hydroxyapatite (HA) is known to promote osteogenicity and enhance the mechanical properties of biopolymers. However, incorporating a large amount of HA into a porous biopolymer still remains a challenge. In the present work, a new method was developed to produce interconnected microporous poly(glycolic-co-lactic acid) (PLGA) with high HA nanoparticle loading. First, a ternary blend comprising PLGA/PS (polystyrene)/HA (40/40/20 wt%) was prepared by melt blending under conditions for formation of a co-continuous phase structure. Next, a dynamic annealing stage under small-strain oscillation was applied to the blend to facilitate nanoparticle redistribution. Finally, the PS phase was sacrificially extracted, leaving a porous matrix. The results from different characterizations suggested that the applied small-strain oscillation substantially accelerated the migration of HA nanoparticles during annealing from the PS phase to the PLGA phase; nearly all HA particles were uniformly presented in the PLGA phase after a short period of annealing. After dissolution of the PS phase, a PLGA material with interconnected microporous structure was successfully produced, with a high HA loading above 30 wt%. The mechanisms beneath the experimental observations, particularly on the enhanced particle migration process, were discussed, and strategies for producing highly particle loaded biopolymers with interconnected microporous structures were proposed.

  6. Development and in vitro characterization of poly(lactide-co-glycolide microspheres loaded with an antibacterial natural drug for the treatment of long-term bacterial infections

    Directory of Open Access Journals (Sweden)

    Reinbold J

    2016-09-01

    microspheres was determined using transmission electron microscopy. No biofilm formation could be detected, even if the totarol concentration was below the minimal inhibitory concentration. The hemocompatibility investigations on various markers with fresh heparinized blood (1.5 IU/mL showed that totarol and totarol-loaded microspheres have no influence on different blood parameters. The PLGA microspheres characterized by slow release of totarol and great entrapment efficiency represent a novel drug delivery system, which may be highly beneficial for the long-term therapy of bacterial infections. Keywords: totarol, drug delivery system, Staphylococcus aureus, antibacterial, cytotoxicity

  7. Morphological, physical, antimicrobial and release properties of ZnO nanoparticles-loaded bacterial cellulose films.

    Science.gov (United States)

    Shahmohammadi Jebel, Fereshteh; Almasi, Hadi

    2016-09-20

    Bacterial cellulose (BC) monolayer and multilayer films, incorporating 5wt.% ZnO nanoparticles (NPs) have been obtained. Ultrasound (US) irradiation (40kHz) was applied during ZnO-BC nanocomposites preparation. X-ray diffraction (XRD) patterns showed that ZnO NPs were crystallized in their pure phase. SEM scanning electron microscopy (SEM) results indicated that US treatment causes to decrease ZnO particle size, forming a stable hybrid nanostructure and evenly distributed ZnO NPs coated BC nanofibers. ZnO NPs enhanced the mechanical properties and diminished water vapor permeability and moisture absorption of BC films. Antibacterial activity of ZnO-BC films against Staphylococcus aureus was more than Escherichia coli. The antibacterial activity was enhanced with the utilization of US irradiation. The ZnO release was influenced by films composition; the multilayer and US treated films being promising in order to achieve controlled release of ZnO. Results suggest that ZnO-BC films may be used as controlled release antimicrobial food active packaging.

  8. Bacterial Communities in Women with Bacterial Vaginosis: High Resolution Phylogenetic Analyses Reveal Relationships of Microbiota to Clinical Criteria

    Science.gov (United States)

    Srinivasan, Sujatha; Hoffman, Noah G.; Morgan, Martin T.; Matsen, Frederick A.; Fiedler, Tina L.; Hall, Robert W.; Ross, Frederick J.; McCoy, Connor O.; Bumgarner, Roger; Marrazzo, Jeanne M.; Fredricks, David N.

    2012-01-01

    Background Bacterial vaginosis (BV) is a common condition that is associated with numerous adverse health outcomes and is characterized by poorly understood changes in the vaginal microbiota. We sought to describe the composition and diversity of the vaginal bacterial biota in women with BV using deep sequencing of the 16S rRNA gene coupled with species-level taxonomic identification. We investigated the associations between the presence of individual bacterial species and clinical diagnostic characteristics of BV. Methodology/Principal Findings Broad-range 16S rRNA gene PCR and pyrosequencing were performed on vaginal swabs from 220 women with and without BV. BV was assessed by Amsel’s clinical criteria and confirmed by Gram stain. Taxonomic classification was performed using phylogenetic placement tools that assigned 99% of query sequence reads to the species level. Women with BV had heterogeneous vaginal bacterial communities that were usually not dominated by a single taxon. In the absence of BV, vaginal bacterial communities were dominated by either Lactobacillus crispatus or Lactobacillus iners. Leptotrichia amnionii and Eggerthella sp. were the only two BV-associated bacteria (BVABs) significantly associated with each of the four Amsel’s criteria. Co-occurrence analysis revealed the presence of several sub-groups of BVABs suggesting metabolic co-dependencies. Greater abundance of several BVABs was observed in Black women without BV. Conclusions/Significance The human vaginal bacterial biota is heterogeneous and marked by greater species richness and diversity in women with BV; no species is universally present. Different bacterial species have different associations with the four clinical criteria, which may account for discrepancies often observed between Amsel and Nugent (Gram stain) diagnostic criteria. Several BVABs exhibited race-dependent prevalence when analyzed in separate groups by BV status which may contribute to increased incidence of BV in

  9. Different phenotypes of CD8+ T cells associated with bacterial load in active tuberculosis.

    Science.gov (United States)

    Silva, Bruna Daniella de Souza; Trentini, Monalisa Martins; da Costa, Adeliane Castro; Kipnis, Andre; Junqueira-Kipnis, Ana Paula

    2014-07-01

    Tuberculosis is an infectious disease that affects millions of people worldwide with an annual mortality rate of 1.3 million. The mechanisms contributing to the loss of balance of immune responses and progression to active tuberculosis disease are unknown. Although CD4+ and CD8+ T cells and the cytokines they produce are crucial for protection against tuberculosis they have different roles in tuberculosis immunology. The function of CD4+ T cells has been extensively studied; however, less is known about the phenotype and function of CD8+ T cells. This study evaluated the specific expression of IFN-γ, IL-17, IL-10, and TGF-β and ex vivo expression of perforin and granzyme-B by CD8+ T cells from active tuberculosis individuals compared with latent infected individuals and non-latent infected individuals. Tuberculosis responses were correlated with the baciloscopy score. We observed that the presence of IL-10 and TGF-β expression and down-expression of granzyme-B in CD8+ T cells correlated with increased sputum bacillary load in active tuberculosis individuals. These findings provide new insights into the role of CD8+ T cells in Mycobacterium tuberculosis disease.

  10. Antibiotic-loaded MoS2 nanosheets to combat bacterial resistance via biofilm inhibition

    Science.gov (United States)

    Zhang, Xu; Zhang, Wentao; Liu, Lizhi; Yang, Mei; Huang, Lunjie; Chen, Kai; Wang, Rong; Yang, Baowei; Zhang, Daohong; Wang, Jianlong

    2017-06-01

    The emergence of antibiotic resistance has resulted in increasing difficulty in treating clinical infections associated with biofilm formation, one of the key processes in turn contributing to enhanced antibiotic resistance. With the rapid development of nanotechnology, a new way to overcome antibiotic resistance has opened up. Based on the many and diverse properties of MoS2 nanosheets that have attracted wide attention, in particular their antibacterial potential, herein, a novel antimicrobial agent to combat resistant gram-positive Staphylococcus aureus and gram-negative Salmonella was prepared using chitosan functionalized MoS2 nanosheets loading tetracycline hydrochloride drugs (abbreviated to CM-TH). The antibacterial and anti-biofilm activities of the CM-TH nanocomposites showed the synergetic effect that the combination of nanomaterials and antibiotics was more efficient than either working alone. In particularly, the minimum inhibitory concentration values generally decreased by a factor of dozens, suggesting that CM-TH may become a possible alternative to traditional antibiotics in disrupting biofilms and overcoming antibiotic resistance in treating medical diseases.

  11. Glycol-Substitute for High Power RF Water Loads

    CERN Document Server

    Ebert, Michael

    2005-01-01

    In water loads for high power rf applications, power is dissipated directly into the coolant. Loads for frequencies below approx. 1GHz are ordinarily using an ethylene glycol-water mixture as coolant. The rf systems at DESY utilize about 100 glycol water loads with powers ranging up to 600kW. Due to the increased ecological awareness, the use of glycol is now considered to be problematic. In EU it is forbidden to discharge glycol into the waste water system. In case of cooling system leakages one has to make sure that no glycol is lost. Since it is nearly impossible to avoid any glycol loss in large rf systems, a glycol-substitute was searched for and found. The found sodium-molybdate based substitute is actually a additive for corrosion protection in water systems. Sodium-molybdate is ecologically harmless; for instance, it is also used as fertilizer in agriculture. A homoeopathic dose of 0.4% mixed into deionised water gives better rf absorption characteristics than a 30% glycol mixture. The rf coolant feat...

  12. Experimental investigation of bond strength under high loading rates

    Science.gov (United States)

    Michal, Mathias; Keuser, Manfred; Solomos, George; Peroni, Marco; Larcher, Martin; Esteban, Beatriz

    2015-09-01

    The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw) and the Joint Research Centre (JRC) in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.

  13. Experimental investigation of bond strength under high loading rates

    Directory of Open Access Journals (Sweden)

    Michal Mathias

    2015-01-01

    Full Text Available The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw and the Joint Research Centre (JRC in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.

  14. Gearbox Reliability Collaborative Investigation of Gearbox Motion and High-Speed-Shaft Loads

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jon [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-18

    This paper extends a model-to-test validation effort to examine the effect of different constant rotor torque and moment conditions and intentional generator misalignment on the gearbox motion and high-speed-shaft loads. Fully validating gearbox motion and high-speed-shaft loads across a range of test conditions is a critical precursor to examining the bearing loads, as the gearbox motion and high-speed-shaft loads are the drivers of these bearing loads.

  15. A Comparison of Increases in Volume Load Over 8 Weeks of Low-Versus High-Load Resistance Training.

    Science.gov (United States)

    Schoenfeld, Brad J; Ogborn, Dan; Contreras, Bret; Cappaert, Tom; Silva Ribeiro, Alex; Alvar, Brent A; Vigotsky, Andrew D

    2016-06-01

    It has been hypothesized that the ability to increase volume load (VL) via a progressive increase in the magnitude of load for a given exercise within a given repetition range could enhance the adaptive response to resistance training. The purpose of this study was to compare changes in volume load (VL) over eight weeks of resistance training (RT) in high-versus low-load protocols. Eighteen well-trained men were matched according to baseline strength were randomly assigned to either a low-load RT (LOW, n = 9) where 25 - 35 repetitions were performed per exercise, or a high-load RT (HIGH, n = 9) where 8 - 12 repetitions were performed per exercise. Both groups performed three sets of seven exercises for all major muscles three times per week on non-consecutive days. After adjusting for the pre-test scores, there was a significant difference between the two intervention groups on post-intervention total VL with a very large effect size (F (1, 15) = 16.598, P = .001, ηp(2) = .525). There was a significant relationship between pre-intervention and post-intervention total VL (F (1, 15) = 32.048, P < .0001, ηp(2) = .681) in which the pre-test scores explained 68% of the variance in the post-test scores. This study indicates that low-load RT results in greater accumulations in VL compared to high-load RT over the course of 8 weeks of training.

  16. High Heat Load Properties of Ultra Fine Grain Tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z.; Du, J.; Ge, C. [Lab. of Special Ceramic and P/M, University of Science and Technology, 100083 Beijing (China); Linke, J.; Pintsuk, G. [FZJ-Forschungszentrum Juelich GmbH, Association Euratom-FZJ, Institut fur Plasmaphysik, Postfach 1913, D-52425 Juelich (Germany); Song, S.X. [Research Center on Fusion Materials (RCFM), University of Science and Technology Beijing (USTB), 100083 Beijing (China)

    2007-07-01

    Full text of publication follows: Tungsten is increasingly considered as a promising candidate armour materials facing the plasma in tokamaks for medium to high heat flux components (EAST, ASDEX, ITER). Fabrication tungsten with ultra fine grain size is considered as an effective way to ameliorate some disadvantages of tungsten, such as its brittleness at room temperature. But the research data on the performance of ultra fine grain tungsten is still very limit. In this work, high heat load properties of pure ultra-fine grain tungsten have been studied. The ultra fine grain tungsten samples with average grain size of 0.2 {mu}m, 1 {mu}m and 3 {mu}m were fabricated by resistance sintering under ultra high pressure. The annealing experiments for the investigation of the material resistance against grain growth have been done by annealing samples in a vacuum furnace at different temperature holding for 2 hours respectively. It is found that recrystallization and grain growth occur at heating temperature of 1250 deg. c. The finer the initial grain sizes of tungsten, the smaller its grain growth grain. The effects of transient high thermal loads (off normal events like disruptions) on tungsten surface morphology have been performed in electron beam test facility JUDITH. The thermal loads tests have been carried out with 4 ms pulses at different power density of 0.22, 0.33, 0.44, 0.55 and 0.88 GW/m{sup 2} respectively. Horizontal cracks formed for all tungsten samples at 0.44 GW/m{sup 2}. Particle erosions occurred for tungsten with 3 {mu}m size at 0.33 GW/m{sup 2} and for tungsten with 0.2 and 1 {mu}m size at 0.55 GW/m{sup 2}. The weight loss of tungsten with 0.2, 1 and 3 {mu}m size are 2,0.1,0.6 mg respectively at 0.88 GW/m{sup 2}. The effects of a large number of very short transient repetitive thermal loads (ELM-like) on tungsten surface morphology also have been performed by using a fundamental wave of a YAG laser. It is found that tungsten with 0.2 {mu}m size has

  17. Enhancing pesticide degradation using indigenous microorganisms isolated under high pesticide load in bioremediation systems with vermicomposts.

    Science.gov (United States)

    Castillo Diaz, Jean Manuel; Delgado-Moreno, Laura; Núñez, Rafael; Nogales, Rogelio; Romero, Esperanza

    2016-08-01

    In biobed bioremediation systems (BBSs) with vermicomposts exposed to a high load of pesticides, 6 bacteria and 4 fungus strains were isolated, identified, and investigated to enhance the removal of pesticides. Three different mixtures of BBSs composed of vermicomposts made from greenhouse (GM), olive-mill (OM) and winery (WM) wastes were contaminated, inoculated, and incubated for one month (GMI, OMI and WMI). The inoculums maintenance was evaluated by DGGE and Q-PCR. Pesticides were monitored by HPLC-DAD. The highest bacterial and fungal abundance was observed in WMI and OMI respectively. In WMI, the consortia improved the removal of tebuconazole, metalaxyl, and oxyfluorfen by 1.6-, 3.8-, and 7.7-fold, respectively. The dissipation of oxyfluorfen was also accelerated in OMI, with less than 30% remaining after 30d. One metabolite for metalaxyl and 4 for oxyfluorfen were identified by GC-MS. The isolates could be suitable to improve the efficiency of bioremediation systems.

  18. Survivability of MEMS Packages at High-G Loads

    Science.gov (United States)

    Pryputniewicz, Ryszard J.

    2014-10-01

    Advances in emerging technology of microelectromechanical systems (MEMS) are one of the most challenging tasks in today's experimental mechanics. More specifically, development of these miniature devices requires sophisticated design, analysis, fabrication, testing, and characterization tools that have multiphysics and multiscale capabilities, especially as MEMS are being developed for use at harsh conditions. In harsh-environment and high-performance (e.g., military) guidance applications inertial sensors must be sensitive to low rates of rotation yet survive the high blast loads associated with the initial launch. In this multi-year study, a set of tuning fork gyroscopes were subjected to a series of increasing g-loads (culminating at approximately 60,000 g's) with measurements of shape made after each test. A custom set of test sample packages (aka articles) were hermetically sealed with glass lids to allow optical inspection of components while preserving the operating environment (i.e., vacuum). Initial test measurements were made upon fabrication of the articles. Optical and interferometric measurements have been made prior to and after each shock g-loading. The shape of the tuning fork gyroscope (TFG) test articles was measured using a phase shifting Michelson interferometer with compensation for package cover glass. Full field shape was determined and traces of pertinent structures were extracted for comparison. Failure of the die was observed in the form of fractures below the chip surface as well as fractures in the glass lid sealing the package. Potential causes of the failure are discussed as well as a recommendation for modified packaging techniques to mitigate future component failures.

  19. Workshop on high heat load x-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    A workshop on High Heat Load X-Ray Optics'' was held at Argonne National Laboratory on August 3--5, 1989. The object of this workshop was to discuss recent advances in the art of cooling x-ray optics subject to high heat loads from synchrotron beams. The cooling of the first optical element in the intense photon beams that will be produced in the next generation of synchrotron sources is recognized as one of the major challenges that must be faced before one will be able to use these very intense beams in future synchrotron experiments. Considerable advances have been made in this art during the last few years, but much work remains to be done before the heating problem can be said to be completely solved. Special emphasis was placed on recent cooling experiments and detailed finite element'' and finite difference'' calculations comparing experiment with theory and extending theory to optimize performance.

  20. High load vortex oscillations developed in Francis turbines

    Science.gov (United States)

    Rodriguez, D.; Rivetti, A.; Lucino, C.

    2016-11-01

    Francis turbines operating at high load conditions produce a typical flow pattern in the draft tube cone characterized by the presence of an axisymmetric central vortex. This central cavity could become unstable, generating synchronic pressure pulsations, usually called self-excited oscillations, which propagate into the whole machine. The on-set and size of the central vortex cavity depend on the geometry of the runner and draft tube and on the operating point as well. Numerical flow simulations and model tests allow for the characterization of the different flow patterns induced by each particular Francis turbine design and, when studied in combination with the hydraulic system, including the intake and penstock, could predict the prototype hydraulic behavior for the complete operation zone. The present work focuses the CFD simulation on the development and dynamic behavior of the central axisymmetric vortex for a medium-head Francis turbine operating at high load conditions. The CFD simulations are based in two-phase transient calculations. Oscillation frequencies against its cavity volume development were obtained and good correlation was found with experimental results.

  1. Treatment of Helicobacter pylori infected mice with Bryophyllum pinnatum, a medicinal plant with antioxidant and antimicrobial properties, reduces bacterial load.

    Science.gov (United States)

    Kouitcheu Mabeku, Laure Brigitte; Eyoum Bille, Bertrand; Tchouangueu, Thibau Flaurant; Nguepi, Eveline; Leundji, Hubert

    2017-12-01

    Bryophyllum pinnatum (Lam.) Kurz (Crassulaceae) is a plant known for its antiulcer properties. This study evaluates the anti-Helicobacter pylori activity of Bryophyllum pinnutum methanol extract with a mouse model and its antioxidant properties. Dried leaves of Bryophyllum pinnutum were extracted with methanol and ethyl acetate. Broth microdilution method was used to evaluate the anti-Helicobacter activity of extract samples in vitro. Swiss mice were inoculated with a suspension of Helicobacter pylori and divided into control group and four others that received 125, 250, 500 mg/kg of methanol extract or ciprofloxacin (500 mg/kg), respectively, for 7 days. Helicobacter pylori colonization and bacterial load of mouse stomach was assessed on day 1 and 7 post-treatment. The antioxidant activity of Bryophyllum pinnutum was evaluated through DPPH radical, hydroxyl radical and reducing power assay. Methanol extract showed a significant anti-Helicobacter activity with MIC and MBC values of 32 and 256 μg/mL, respectively. Bryophyllum pinnatum and ciprofloxacin reduced H. pylori colonization of gastric tissue from 100% to 17%. Bryophyllum pinnatum extract (85.91 ± 52.91 CFU) and standard (25.74 ± 16.15 CFU) also reduced significantly (p pylori growth, and may also acts as an antioxidant to protect gastric mucosa against reactive oxygen species.

  2. Effects of cold stress and Salmonella Heidelberg infection on bacterial load and immunity of chickens.

    Science.gov (United States)

    Borsoi, Anderlise; Quinteiro-Filho, Wanderley Moreno; Calefi, Atilio Sersun; Ferreira, Antonio José Piantino; Astolfi-Ferreira, Claudete Serrano; Florio, Jorge Camilo; Palermo-Neto, João

    2015-01-01

    We analysed the effects of cold stress (19 ± 1°C, 6 h /day, from the first to the seventh day of life) applied to specific pathogen free (SPF) chickens. On experimental Day 1 (ED1), chicks were divided into four groups: C (not infected and kept under thermoneutral condition); CS (not infected and cold stressed); PC (Salmonella Heidelberg (SH) infected and kept under thermoneutral condition) and PCS (SH infected and cold stressed). High concentrations of corticosterone were found in the cold stressed birds on ED7 and ED21, with a greater increase in birds of the PCS group. Stress or non-stressed SH-infected birds had high levels of norepinephrine on ED21. On ED21, an increased percentage and number of SH were found in birds of the PCS group. On ED7, a decrease in macrophages presenting MHCII, CD8(+) and CD8(+) γδ cells was observed in the chickens of the CS group. Decrease was observed in CD3(+) cells in the birds of the PCS group and increase in macrophages presenting MHCII cells and of the CD4(+)/CD8(+) ratio in chickens of the CS group on ED21. There was a decrease in CD8(+) γδ cells in birds of the CS group on ED21 and in the CD3(+) and CD8(+)cell numbers in chickens of the PCS group on ED21. Our results suggest that cold stress applied to chickens in the first 7 days of life increases both the hypothalamus pituitary adrenal axis and the sympathetic nervous system activities, leading to long-term immune cell dysfunction, thus allowing increased SH invasion and persistence within the birds' body.

  3. Impulsive Loading of Armour by High Explosive Squash Head Munition

    Directory of Open Access Journals (Sweden)

    P.U. Deshpande

    2003-10-01

    Full Text Available Results obtained by theoretical modelling studies involving classical stress-strain theories, duly validated by experimental investigation in understanding the mechanism of impulsive loading (scabbing and blast under dynamic and static conditions, are discussed. This concept has been used in designing a high explosive squash head ammunition being effective in defeating monolithic armour. Efforts have been made to carry out an in-depth study in understanding the mechanism of scabbing under static and dynamic (live firing conditions. For this purpose, a one-dimensional computer code has been used to predict the spread of explosive against time on the target. The simulations were carried out using a 2-D Lagrangian hydrodynamic code for scabbing effect. The blast effect that follows under static and dynamic conditions has also been studied. Blast parameters have been computed in terms of TNT equivalent and compared with experimental results. The events occurring during impulsive loading of 135 mm monolithic rolled homogenous armour have been illustrated.

  4. Changes in rocket salad phytochemicals within the commercial supply chain: Glucosinolates, isothiocyanates, amino acids and bacterial load increase significantly after processing.

    Science.gov (United States)

    Bell, Luke; Yahya, Hanis Nadia; Oloyede, Omobolanle Oluwadamilola; Methven, Lisa; Wagstaff, Carol

    2017-04-15

    Five cultivars of Eruca sativa and a commercial variety of Diplotaxis tenuifolia were grown in the UK (summer) and subjected to commercial growth, harvesting and processing, with subsequent shelf life storage. Glucosinolates (GSL), isothiocyanates (ITC), amino acids (AA), free sugars, and bacterial loads were analysed throughout the supply chain to determine the effects on phytochemical compositions. Bacterial load of leaves increased significantly over time and peaked during shelf life storage. Significant correlations were observed with GSL and AA concentrations, suggesting a previously unknown relationship between plants and endemic leaf bacteria. GSLs, ITCs and AAs increased significantly after processing and during shelf life. The supply chain did not significantly affect glucoraphanin concentrations, and its ITC sulforaphane significantly increased during shelf life in E. sativa cultivars. We hypothesise that commercial processing may increase the nutritional value of the crop, and have added health benefits for the consumer.

  5. Drip Line Flushing with Chlorine May Not Be Effective in Reducing Bacterial Loads in Irrigation Water Distribution Systems.

    Science.gov (United States)

    Callahan, Mary Theresa; Marine, Sasha C; Everts, Kathryne L; Micallef, Shirley A

    2016-06-01

    Irrigation water distribution systems are used to supply water to produce crops, but the system may also provide a protected environment for the growth of human pathogens present in irrigation water. In this study, the effects of drip tape installation depth and sanitization on the microbial quality of irrigation groundwater were evaluated. Drip tape lines were installed on the soil surface or 5 or 10 cm below the soil surface. Water samples were collected from the irrigation source and the end of each drip line every 2 weeks over an 11-week period, and the levels of Escherichia coli, total coliforms, aerobic mesophilic bacteria, and enterococci were quantified. Half of the lines installed at each depth were flushed with sodium hypochlorite for 1 h during week 6 to achieve a residual of 10 ppm at the end of the line. There was a statistically significant (P = 0.01) effect of drip tape installation depth and sanitizer application on the recovery of E. coli, with increased levels measured at the 5-cm depth and in nonsanitized lines, although the levels were at the limit of detection, potentially confounding the results. There was no significant effect of drip tape depth on total coliforms, aerobic mesophiles, or enterococci. In contrast, a statistically significant increase (P < 0.01) in the recovery of total coliforms was recorded from the ends of lines that received chlorine. This may be indicative of shedding of cells owing to degradation of biofilms that formed on the inner walls of the lines. These findings emphasize the need to better understand conditions that may lead to corrosion and increases in bacterial loads inside drip lines during flushing. Recommendations to growers should suggest collecting groundwater samples for testing at the end of drip lines rather than at the source. Guidelines on flushing drip lines with chlorine may need to include water pH monitoring, a parameter that influences the corrosive properties of chlorine.

  6. Application of high-turning bowed compressor stator to redesign of highly loaded fan stage

    Institute of Scientific and Technical Information of China (English)

    Shaobin LI; Jiexian SU; Zhongqi WANG

    2008-01-01

    A redesign of a highly loaded fan stage by using high-turning bowed compressor stator was conducted. The original tandem stator was replaced by the highly loaded bowed stator which was applicable to highly sub-sonic flow conditions. 3D contouring technique and local modification of blade were applied to the design of the bowed blade in order to improve the aerodynamic per-formance and the matching of the rotor and stator blade rows. Performance curves at different rotating speeds and performances at different operating points for both the original fan stage and redesigned fan stage were obtained by numerical simulations. The results show that the highly loaded bowed stator can be used not only to improve the structure and the aerodynamic performances at various operating points of the compressor stage but also to pro-vide high performances at off-design conditions. It is believed that the highly loaded bowed stator can advance the design of high-performance compressor.

  7. A Comparison of Increases in Volume Load Over 8 Weeks of Low-Versus High-Load Resistance Training

    Directory of Open Access Journals (Sweden)

    Schoenfeld

    2016-01-01

    Full Text Available Background It has been hypothesized that the ability to increase volume load (VL via a progressive increase in the magnitude of load for a given exercise within a given repetition range could enhance the adaptive response to resistance training. Objectives The purpose of this study was to compare changes in volume load (VL over eight weeks of resistance training (RT in high-versus low-load protocols. Materials and Methods Eighteen well-trained men were matched according to baseline strength were randomly assigned to either a low-load RT (LOW, n = 9 where 25 - 35 repetitions were performed per exercise, or a high-load RT (HIGH, n = 9 where 8 - 12 repetitions were performed per exercise. Both groups performed three sets of seven exercises for all major muscles three times per week on non-consecutive days. Results After adjusting for the pre-test scores, there was a significant difference between the two intervention groups on post-intervention total VL with a very large effect size (F (1, 15 = 16.598, P = .001, ηp2 = .525. There was a significant relationship between pre-intervention and post-intervention total VL (F (1, 15 = 32.048, P < .0001, ηp2 = .681 in which the pre-test scores explained 68% of the variance in the post-test scores. Conclusions This study indicates that low-load RT results in greater accumulations in VL compared to high-load RT over the course of 8 weeks of training.

  8. Rectangular Dielectric-loaded Structures for Achieving High Acceleration Gradients

    Science.gov (United States)

    Wang, Changbiao; Yakovlev, V. P.; Marshall, T. C.; LaPointe, M. A.; Hirshfield, J. L.

    2006-11-01

    Rectangular dielectric-loaded structures are described that may sustain higher acceleration gradients than conventional all-metal structures with similar apertures. One structure is a test cavity designed to ascertain the breakdown limits of dielectrics, while a second structure could be the basis for a two-beam accelerator. CVD diamond is an attractive dielectric for a high-gradient structure, since the published DC breakdown limit for CVD diamond is ˜ 2 GV/m, although the limit has never been determined for RF fields. Here we present a design of a diamond-lined test cavity to measure the breakdown limit. The designed cavity operates at 34 GHz, where with 10-MW input power it is expected to produce an ˜800 MV/m field on the diamond surface—provided breakdown is avoided. The two channel rectangular dielectric-loaded waveguide could be a two-beam accelerator structure, in which a drive beam is in one channel and an accelerated beam is in the other. The RF power produced by drive bunches in the drive channel is continuously coupled to the acceleration channel. The ratio of fields in the channels (transformer ratio) for the operating mode can be designed by adjusting the dimensions of the structure. An example of the two-channel structure is described, in which a train of five 3-nC drive bunches excites wake fields in the accelerator channel of up to 1.3 GV/m with a transformer ratio of 10 for the design mode.

  9. High- and low-affinity binding sites for Cd on the bacterial cell walls of Bacillus subtilis and Shewanella oneidensis

    Science.gov (United States)

    Mishra, Bhoopesh; Boyanov, Maxim; Bunker, Bruce A.; Kelly, Shelly D.; Kemner, Kenneth M.; Fein, Jeremy B.

    2010-08-01

    Bulk Cd adsorption isotherm experiments, thermodynamic equilibrium modeling, and Cd K edge EXAFS were used to constrain the mechanisms of proton and Cd adsorption to bacterial cells of the commonly occurring Gram-positive and Gram-negative bacteria, Bacillus subtilis and Shewanella oneidensis, respectively. Potentiometric titrations were used to characterize the functional group reactivity of the S. oneidensis cells, and we model the titration data using the same type of non-electrostatic surface complexation approach as was applied to titrations of B. subtilis suspensions by Fein et al. (2005). Similar to the results for B. subtilis, the S. oneidensis cells exhibit buffering behavior from approximately pH 3-9 that requires the presence of four distinct sites, with p Ka values of 3.3 ± 0.2, 4.8 ± 0.2, 6.7 ± 0.4, and 9.4 ± 0.5, and site concentrations of 8.9(±2.6) × 10 -5, 1.3(±0.2) × 10 -4, 5.9(±3.3) × 10 -5, and 1.1(±0.6) × 10 -4 moles/g bacteria (wet mass), respectively. The bulk Cd isotherm adsorption data for both species, conducted at pH 5.9 as a function of Cd concentration at a fixed biomass concentration, were best modeled by reactions with a Cd:site stoichiometry of 1:1. EXAFS data were collected for both bacterial species as a function of Cd concentration at pH 5.9 and 10 g/L bacteria. The EXAFS results show that the same types of binding sites are responsible for Cd sorption to both bacterial species at all Cd loadings tested (1-200 ppm). Carboxyl sites are responsible for the binding at intermediate Cd loadings. Phosphoryl ligands are more important than carboxyl ligands for Cd binding at high Cd loadings. For the lowest Cd loadings studied here, a sulfhydryl site was found to dominate the bound Cd budgets for both species, in addition to the carboxyl and phosphoryl sites that dominate the higher loadings. The EXAFS results suggest that both Gram-positive and Gram-negative bacterial cell walls have a low concentration of very high

  10. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea).

    Science.gov (United States)

    Amer, Ranya A; Mapelli, Francesca; El Gendi, Hamada M; Barbato, Marta; Goda, Doaa A; Corsini, Anna; Cavalca, Lucia; Fusi, Marco; Borin, Sara; Daffonchio, Daniele; Abdel-Fattah, Yasser R

    2015-01-01

    Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt). Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  11. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Ranya A. Amer

    2015-01-01

    Full Text Available Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt. Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  12. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea)

    KAUST Repository

    Amer, Ranya A.

    2015-02-01

    Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt). Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  13. Microfluidic generation of droplets with a high loading of nanoparticles.

    Science.gov (United States)

    Wan, Jiandi; Shi, Lei; Benson, Bryan; Bruzek, Matthew J; Anthony, John E; Sinko, Patrick J; Prudhomme, Robert K; Stone, Howard A

    2012-09-18

    Microfluidic approaches for controlled generation of colloidal clusters, for example, via encapsulation of colloidal particles in droplets, have been used for the synthesis of functional materials including drug delivery carriers. Most of the studies, however, use a low concentration of an original colloidal suspension (microfluidic approaches for directly making droplets with moderate (10-25 wt %) and high (>60 wt %) particle concentrations. Three types of microfluidic devices, PDMS flow-focusing, PDMS T-junction, and microcapillary devices, are investigated for direct encapsulation of a high concentration of polystyrene (PS) nanoparticles in droplets. In particular, it is shown that PDMS devices fabricated by soft lithography can generate droplets from a 25 wt % PS suspension, whereas microcapillary devices made from glass capillary tubes are able to produce droplets from a 67 wt % PS nanoparticle suspension. When the PS concentration is between 0.6 and 25 wt %, the size of the droplets is found to change with the oil-to-water flow rate ratio and is independent of the concentration of particles in the initial suspensions. Drop sizes from ~12 to 40 μm are made using flow rate ratios Q(oil)/Q(water) from 20 to 1, respectively, with either of the PDMS devices. However, clogging occurs in PDMS devices at high PS concentrations (>25 wt %) arising from interactions between the PS colloids and the surface of PDMS devices. Glass microcapillary devices, on the other hand, are resistant to clogging and can produce droplets continuously even when the concentration of PS nanoparticles reaches 67 wt %. We believe that our findings indicate useful approaches and guidelines for the controlled generation of emulsions filled with a high loading of nanoparticles, which are useful for drug delivery applications.

  14. High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments.

    Science.gov (United States)

    Dell'Anno, Antonio; Beolchini, Francesca; Rocchetti, Laura; Luna, Gian Marco; Danovaro, Roberto

    2012-08-01

    We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments.

  15. The Use of Different Irrigation Techniques to Decrease Bacterial Loads in Healthy and Diabetic Patients with Asymptomatic Apical Periodontitis

    Directory of Open Access Journals (Sweden)

    Mai Ghoneim

    2016-12-01

    CONCLUSION: The EndoVac can be considered as a promising tool in combination with irrigant solution to defeat the bacterial colonies living in the root canal system. Additional studies ought to be done to improve the means of bacterial clearance mainly in immune-compromised individuals.

  16. Bacterial natural transformation by highly fragmented and damaged DNA

    DEFF Research Database (Denmark)

    Overballe-Petersen, Søren; Harms, Klaus; Orlando, Ludovic Antoine Alexandre

    2013-01-01

    of DNA from a 43,000-y-old woolly mammoth bone, we further demonstrate that such natural transformation events include ancient DNA molecules. We find that the DNA recombination is RecA recombinase independent and is directly linked to DNA replication. We show that the adjacent nucleotide variations......DNA molecules are continuously released through decomposition of organic matter and are ubiquitous in most environments. Such DNA becomes fragmented and damaged (often DNA is recognized as nutrient source...... for microbes, but not as potential substrate for bacterial evolution. Here, we show that fragmented DNA molecules (≥20 bp) that additionally may contain abasic sites, cross-links, or miscoding lesions are acquired by the environmental bacterium Acinetobacter baylyi through natural transformation. With uptake...

  17. High temperature and bacteriophages can indirectly select for bacterial pathogenicity in environmental reservoirs.

    Directory of Open Access Journals (Sweden)

    Ville-Petri Friman

    Full Text Available The coincidental evolution hypothesis predicts that traits connected to bacterial pathogenicity could be indirectly selected outside the host as a correlated response to abiotic environmental conditions or different biotic species interactions. To investigate this, an opportunistic bacterial pathogen, Serratia marcescens, was cultured in the absence and presence of the lytic bacteriophage PPV (Podoviridae at 25°C and 37°C for four weeks (N = 5. At the end, we measured changes in bacterial phage-resistance and potential virulence traits, and determined the pathogenicity of all bacterial selection lines in the Parasemia plantaginis insect model in vivo. Selection at 37°C increased bacterial motility and pathogenicity but only in the absence of phages. Exposure to phages increased the phage-resistance of bacteria, and this was costly in terms of decreased maximum population size in the absence of phages. However, this small-magnitude growth cost was not greater with bacteria that had evolved in high temperature regime, and no trade-off was found between phage-resistance and growth rate. As a result, phages constrained the evolution of a temperature-mediated increase in bacterial pathogenicity presumably by preferably infecting the highly motile and virulent bacteria. In more general perspective, our results suggest that the traits connected to bacterial pathogenicity could be indirectly selected as a correlated response by abiotic and biotic factors in environmental reservoirs.

  18. Participation of Flexible Loads in Load Frequency Control to Support High Wind Penetration

    DEFF Research Database (Denmark)

    uslu, umur; Zhang, Boyang; Pillai, Jayakrishnan Radhakrishna;

    2016-01-01

    The increasing amount of fluctuating wind power penetration in power systems presents many challenges to its operation and control. The new wind power plants are replacing many of the conventional large power plants that ensure power balancing and ancillary services for stable and reliable...... operation of the grid. Therefore, new solutions for power balancing reserves have to be explored and utilized by the grid utilities. To meet these challenges, large sizable loads like alkaline electrolysers, heat pumps and electric vehicles which are gaining popularity can provide system support to the grid...... through their inherent flexibility and energy storage characteristics. This paper investigates the possibilities and potential of such flexible loads to participate in power system frequency regulation in a wind dominated power system. The results show that these consumption units provide better...

  19. Association of High Orientia tsutsugamushi DNA Loads with Disease of Greater Severity in Adults with Scrub Typhus▿

    Science.gov (United States)

    Sonthayanon, Piengchan; Chierakul, Wirongrong; Wuthiekanun, Vanaporn; Phimda, Kriangsak; Pukrittayakamee, Sasithon; Day, Nicholas P.; Peacock, Sharon J.

    2009-01-01

    Orientia tsutsugamushi, the cause of scrub typhus, is a major pathogen in the Asia-Pacific region. The severity of infection ranges from mild features to multiorgan failure and death. The aim of this prospective study was to define the O. tsutsugamushi loads in the blood samples of patients with scrub typhus on the day of hospital admission and to determine whether this was associated with disease severity. Quantitation was performed using a real-time PCR assay targeting the 16S rRNA gene of O. tsutsugamushi. A total of 155 patients with a confirmed diagnosis of scrub typhus had a median (interquartile range [IQR], range) O. tsutsugamushi DNA load in blood of 13 (0 to 334, 0 to 310,253) copies/ml. This included 74 patients who had undetectable bacterial loads. An analysis of bacterial load versus clinical features for all 155 patents demonstrated that duration of illness (P < 0.001), presence of eschar (P = 0.004), and concentrations of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase (P < 0.001 for all three) were positively correlated with bacterial load. Patients who died had a significantly higher bacterial load than those who survived (mean [standard deviation] values: 17,154 [12.7] versus 281 [5.2] copies/ml; P < 0.001). This study has demonstrated a relationship between bacterial load and disease severity in adults with scrub typhus. PMID:19091812

  20. Balancing the organic load and light supply in symbiotic microalgal–bacterial biofilm reactors treating synthetic municipal wastewater

    NARCIS (Netherlands)

    Boelee, N.C.; Temmink, B.G.; Janssen, M.; Buisman, C.J.N.; Wijffels, R.H.

    2014-01-01

    Symbiotic microalgal–bacterial biofilms can be very attractive for municipal wastewater treatment. Microalgae remove nitrogen and phosphorus and simultaneously produce the oxygen that is required for the aerobic, heterotrophic degradation of organic pollutants. For the application of these biofilms

  1. Balancing the organic load and light supply in symbiotic microalgal–bacterial biofilm reactors treating synthetic municipal wastewater

    NARCIS (Netherlands)

    Boelee, N.C.; Temmink, B.G.; Janssen, M.; Buisman, C.J.N.; Wijffels, R.H.

    2014-01-01

    Symbiotic microalgal–bacterial biofilms can be very attractive for municipal wastewater treatment. Microalgae remove nitrogen and phosphorus and simultaneously produce the oxygen that is required for the aerobic, heterotrophic degradation of organic pollutants. For the application of these biofilms

  2. The Use of Different Irrigation Techniques to Decrease Bacterial Loads in Healthy and Diabetic Patients with Asymptomatic Apical Periodontitis

    Science.gov (United States)

    Ghoneim, Mai; Saber, Shehab ElDin; El-Badry, Tarek; Obeid, Maram; Hassib, Nehal

    2016-01-01

    BACKGROUND: Diabetes mellitus is a multisystem disease which weakens the human’s immunity. Subsequently, it worsens the sequelae of apical periodontitis by raising a fierce bacterial trait due to the impaired host response. AIM: This study aimed to estimate bacterial reduction after using different irrigation techniques in systemically healthy and diabetic patients with asymptomatic apical periodontitis. MATERIAL AND METHODS: Enterococcus faecalis, Peptostreptococcus micros, and Fusobacterium necleatum bacteria were chosen, as they are the most common and prevailing strains found in periodontitis. Bacterial samples were retrieved from necrotic root canals of systemically healthy and diabetic patients, before and after endodontic cleaning and shaping by using two different irrigation techniques; the conventional one and the EndoVac system. Quantitive polymerase chain reaction (qPCR) was utilised to detect the reduction in the bacterial count. RESULTS: The EndoVac irrigation system was effective in reducing bacteria, especially Peptostreptococcus micros in the diabetic group when compared to conventional irrigation technique with a statistically significant difference. CONCLUSION: The EndoVac can be considered as a promising tool in combination with irrigant solution to defeat the bacterial colonies living in the root canal system. Additional studies ought to be done to improve the means of bacterial clearance mainly in immune-compromised individuals. PMID:28028421

  3. Correlation between Clostridium difficile bacterial load, commercial real-time PCR cycle thresholds, and results of diagnostic tests based on enzyme immunoassay and cell culture cytotoxicity assay.

    Science.gov (United States)

    Dionne, Léa-Laurence; Raymond, Frédéric; Corbeil, Jacques; Longtin, Jean; Gervais, Philippe; Longtin, Yves

    2013-11-01

    The impact of Clostridium difficile fecal loads on diagnostic test results is poorly understood, but it may have clinical importance. In this study, we investigated the relationship between C. difficile fecal load and the results of four assays: a glutamate dehydrogenase (GDH) enzyme immunoassay (EIA), a toxin A/B antigen EIA (ToxAB), a cell culture cytotoxicity assay (CCA), and PCR targeting the tcdB gene. We also compared the PCR cycle threshold (CT) with the results of quantitative culture using Spearman's rank correlation coefficient. Finally, we sequenced the genomes of 24 strains with different detection profiles. A total of 203 clinical samples harboring toxigenic C. difficile were analyzed and sorted into one of four groups: 17 PCR(+) (group 1), 37 PCR(+) GDH(+) (group 2), 24 PCR(+) GDH(+) CCA(+) (group 3), and 125 PCR(+) GDH(+) ToxAB(+) (group 4). The overall median fecal load in log10 CFU/g was 6.67 (interquartile range [IQR], 5.57 to 7.54). The median fecal bacterial load of groups 1, 2, 3, and 4 were 4.15 (IQR, 3.00 to 4.98), 5.74 (IQR, 4.75 to 6.16), 6.20 (IQR, 5.23 to 6.80), and 7.08 (IQR, 6.35 to 7.83), respectively. Group 1 samples had lower fecal loads than those from each of the other groups (P tests.

  4. Sex differences in verbal working memory performance emerge at very high loads of common neuroimaging tasks.

    Science.gov (United States)

    Reed, Jessica L; Gallagher, Natalie M; Sullivan, Marie; Callicott, Joseph H; Green, Adam E

    2017-04-01

    Working memory (WM) supports a broad range of intelligent cognition and has been the subject of rich cognitive and neural characterization. However, the highest ranges of WM have not been fully characterized, especially for verbal information. Tasks developed to test multiple levels of WM demand (load) currently predominate brain-based WM research. These tasks are typically used at loads that allow most healthy participants to perform well, which facilitates neuroimaging data collection. Critically, however, high performance at lower loads may obscure differences that emerge at higher loads. A key question not yet addressed at high loads concerns the effect of sex. Thoroughgoing investigation of high-load verbal WM is thus timely to test for potential hidden effects, and to provide behavioral context for effects of sex observed in WM-related brain structure and function. We tested 111 young adults, matched on genotype for the WM-associated COMT-Val(108/158)Met polymorphism, on three classic WM tasks using verbal information. Each task was tested at four WM loads, including higher loads than those used in previous studies of sex differences. All tasks loaded on a single factor, enabling comparison of verbal WM ability at a construct level. Results indicated sex effects at high loads across tasks and within each task, such that males had higher accuracy, even among groups that were matched for performance at lower loads.

  5. Participation of Flexible Loads in Load Frequency Control to Support High Wind Penetration

    DEFF Research Database (Denmark)

    Uslu, Umur; Zhang, Boyang; Pillai, Jayakrishnan Radhakrishna;

    2016-01-01

    The increasing amount of fluctuating wind power penetration in power systems presents many challenges to its operation and control. The new wind power plants are replacing many of the conventional large power plants that ensure power balancing and ancillary services for stable and reliable...... operation of the grid. Therefore, new solutions for power balancing reserves have to be explored and utilized by the grid utilities. To meet these challenges, large sizable loads like alkaline electrolysers, heat pumps and electric vehicles which are gaining popularity can provide system support to the grid...... performance for balancing the power than the conventional generation reserves....

  6. Can the Bacterial Community of a High Arctic Glacier Surface Escape Viral Control?

    Science.gov (United States)

    Rassner, Sara M. E.; Anesio, Alexandre M.; Girdwood, Susan E.; Hell, Katherina; Gokul, Jarishma K.; Whitworth, David E.; Edwards, Arwyn

    2016-01-01

    Glacial ice surfaces represent a seasonally evolving three-dimensional photic zone which accumulates microbial biomass and potentiates positive feedbacks in ice melt. Since viruses are abundant in glacial systems and may exert controls on supraglacial bacterial production, we examined whether changes in resource availability would promote changes in the bacterial community and the dynamics between viruses and bacteria of meltwater from the photic zone of a Svalbard glacier. Our results indicated that, under ambient nutrient conditions, low estimated viral decay rates account for a strong viral control of bacterial productivity, incurring a potent viral shunt of a third of bacterial carbon in the supraglacial microbial loop. Moreover, it appears that virus particles are very stable in supraglacial meltwater, raising the prospect that viruses liberated in melt are viable downstream. However, manipulating resource availability as dissolved organic carbon, nitrogen, and phosphorous in experimental microcosms demonstrates that the photic zone bacterial communities can escape viral control. This is evidenced by a marked decline in virus-to-bacterium ratio (VBR) concomitant with increased bacterial productivity and number. Pyrosequencing shows a few bacterial taxa, principally Janthinobacterium sp., dominate both the source meltwater and microcosm communities. Combined, our results suggest that viruses maintain high VBR to promote contact with low-density hosts, by the manufacture of robust particles, but that this necessitates a trade-off which limits viral production. Consequently, dominant bacterial taxa appear to access resources to evade viral control. We propose that a delicate interplay of bacterial and viral strategies affects biogeochemical cycling upon glaciers and, ultimately, downstream ecosystems. PMID:27446002

  7. Can the Bacterial Community of a High Arctic Glacier Surface Escape Viral Control?

    Science.gov (United States)

    Rassner, Sara M E; Anesio, Alexandre M; Girdwood, Susan E; Hell, Katherina; Gokul, Jarishma K; Whitworth, David E; Edwards, Arwyn

    2016-01-01

    Glacial ice surfaces represent a seasonally evolving three-dimensional photic zone which accumulates microbial biomass and potentiates positive feedbacks in ice melt. Since viruses are abundant in glacial systems and may exert controls on supraglacial bacterial production, we examined whether changes in resource availability would promote changes in the bacterial community and the dynamics between viruses and bacteria of meltwater from the photic zone of a Svalbard glacier. Our results indicated that, under ambient nutrient conditions, low estimated viral decay rates account for a strong viral control of bacterial productivity, incurring a potent viral shunt of a third of bacterial carbon in the supraglacial microbial loop. Moreover, it appears that virus particles are very stable in supraglacial meltwater, raising the prospect that viruses liberated in melt are viable downstream. However, manipulating resource availability as dissolved organic carbon, nitrogen, and phosphorous in experimental microcosms demonstrates that the photic zone bacterial communities can escape viral control. This is evidenced by a marked decline in virus-to-bacterium ratio (VBR) concomitant with increased bacterial productivity and number. Pyrosequencing shows a few bacterial taxa, principally Janthinobacterium sp., dominate both the source meltwater and microcosm communities. Combined, our results suggest that viruses maintain high VBR to promote contact with low-density hosts, by the manufacture of robust particles, but that this necessitates a trade-off which limits viral production. Consequently, dominant bacterial taxa appear to access resources to evade viral control. We propose that a delicate interplay of bacterial and viral strategies affects biogeochemical cycling upon glaciers and, ultimately, downstream ecosystems.

  8. Effects of high hydrostatic pressure on bacterial growth on human ossicles explanted from cholesteatoma patients.

    Science.gov (United States)

    Dommerich, Steffen; Frickmann, Hagen; Ostwald, Jürgen; Lindner, Tobias; Zautner, Andreas Erich; Arndt, Kathleen; Pau, Hans Wilhelm; Podbielski, Andreas

    2012-01-01

    High hydrostatic pressure (HHP) treatment can eliminate cholesteatoma cells from explanted human ossicles prior to re-insertion. We analyzed the effects of HHP treatment on the microbial flora on ossicles and on the planktonic and biofilm states of selected isolates. Twenty-six ossicles were explanted from cholesteatoma patients. Five ossicles were directly analyzed for microbial growth without further treatment. Fifteen ossicles were cut into two pieces. One piece was exposed to HHP of 350 MPa for 10 minutes. Both the treated and untreated (control) pieces were then assessed semi-quantitatively. Three ossicles were cut into two pieces and exposed to identical pressure conditions with or without the addition of one of two different combinations of antibiotics to the medium. Differential effects of 10-minute in vitro exposure of planktonic and biofilm bacteria to pressures of 100 MPa, 250 MPa, 400 MPa and 540 MPa in isotonic and hypotonic media were analyzed using two patient isolates of Staphylococcus epidermidis and Neisseria subflava. Bacterial cell inactivation and biofilm destruction were assessed by colony counting and electron microscopy. A variety of microorganisms were isolated from the ossicles. Irrespective of the medium, HHP treatment at 350 MPa for 10 minutes led to satisfying but incomplete inactivation especially of gram-negative bacteria. The addition of antibiotics increased the efficacy of elimination. A comparison of HHP treatment of planktonic and biofilm cells showed that the effects of HPP were reduced by about one decadic logarithmic unit when HPP was applied to biofilms. High hydrostatic pressure conditions that are suitable to inactivate cholesteatoma cells fail to completely sterilize ossicles even if antibiotics are added. As a result of the reduced microbial load and the viability loss of surviving bacteria, however, there is a lower risk of re-infection after re-insertion.

  9. Yellowstone Lake: high-energy geochemistry and rich bacterial diversity.

    Science.gov (United States)

    Clingenpeel, Scott; Macur, Richard E; Kan, Jinjun; Inskeep, William P; Lovalvo, Dave; Varley, John; Mathur, Eric; Nealson, Kenneth; Gorby, Yuri; Jiang, Hongchen; LaFracois, Toben; McDermott, Timothy R

    2011-08-01

    Yellowstone Lake is central to the balanced functioning of the Yellowstone ecosystem, yet little is known about the microbial component of its food chain. A remotely operated vehicle provided video documentation (http://www.tbi.montana.edu/media/videos/) and allowed sampling of dilute surface zone waters and enriched lake floor hydrothermal vent fluids. Vent emissions contained substantial H(2)S, CH(4), CO(2) and H(2), although CH(4) and H(2) levels were also significant throughout the lake. Pyrosequencing and near full-length sequencing of Bacteria 16S rRNA gene diversity associated with two vents and two surface water environments demonstrated that this lake contains significant bacterial diversity. Biomass was size-fractionated by sequentially filtering through 20-µm-, 3.0-µm-, 0.8-µm- and 0.1-µm-pore-size filters, with the >0.1 to <0.8 µm size class being the focus of this study. Major phyla included Acidobacteria, Actinobacteria, Bacteroidetes, α- and β-Proteobacteria and Cyanobacteria, with 21 other phyla represented at varying levels. Surface waters were dominated by two phylotypes: the Actinobacteria freshwater acI group and an α-Proteobacteria clade tightly linked with freshwater SAR11-like organisms. We also obtained evidence of novel thermophiles and recovered Prochlorococcus phylotypes (97-100% identity) in one near surface photic zone region of the lake. The combined geochemical and microbial analyses suggest that the foundation of this lake's food chain is not simple. Phototrophy presumably is an important driver of primary productivity in photic zone waters; however, chemosynthetic hydrogenotrophy and methanotrophy are likely important components of the lake's food chain.

  10. Pilot study to evaluate 3 hygiene protocols on the reduction of bacterial load on the hands of veterinary staff performing routine equine physical examinations.

    Science.gov (United States)

    Traub-Dargatz, Josie L; Weese, J Scott; Rousseau, Joyce D; Dunowska, Magdalena; Morley, Paul S; Dargatz, David A

    2006-07-01

    Reduction factors (RFs) for bacterial counts on examiners' hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl alcohol plus 1% chlorhexidine active ingredients) protocols, respectively. The RFs were significantly different (P bacterial load on the hands of people after they perform routine physical examinations.

  11. Distribution of background equivalent static wind load on high-rise buildings

    Institute of Scientific and Technical Information of China (English)

    Jianguo ZHANG; Ming GU

    2009-01-01

    In this paper, the along-wind and cross-wind fluctuating load distributions along the height of high-rise buildings and their correlations are obtained through simultaneous pressure measurements in a wind tunnel.Some typical methods proposed in some relative litera-tures, i.e., load-response correlation (LRC), and quasi-mean load (QML) and gust load envelope (GLE) methods,are verified in terms of their accuracy in describing the background equivalent static wind load distribution on high-rise buildings. Based on the results, formulae of the distribution of background equivalent static load on high-rise buildings with typical shapes are put forward. It is shown that these formulae are of high accuracy and practical use.

  12. Muscular adaptations in low- versus high-load resistance training: A meta-analysis.

    Science.gov (United States)

    Schoenfeld, Brad J; Wilson, Jacob M; Lowery, Ryan P; Krieger, James W

    2016-01-01

    There has been much debate as to optimal loading strategies for maximising the adaptive response to resistance exercise. The purpose of this paper therefore was to conduct a meta-analysis of randomised controlled trials to compare the effects of low-load (≤60% 1 repetition maximum [RM]) versus high-load (≥65% 1 RM) training in enhancing post-exercise muscular adaptations. The strength analysis comprised 251 subjects and 32 effect sizes (ESs), nested within 20 treatment groups and 9 studies. The hypertrophy analysis comprised 191 subjects and 34 ESs, nested with 17 treatment groups and 8 studies. There was a trend for strength outcomes to be greater with high loads compared to low loads (difference = 1.07 ± 0.60; CI: -0.18, 2.32; p = 0.09). The mean ES for low loads was 1.23 ± 0.43 (CI: 0.32, 2.13). The mean ES for high loads was 2.30 ± 0.43 (CI: 1.41, 3.19). There was a trend for hypertrophy outcomes to be greater with high loads compared to low loads (difference = 0.43 ± 0.24; CI: -0.05, 0.92; p = 0.076). The mean ES for low loads was 0.39 ± 0.17 (CI: 0.05, 0.73). The mean ES for high loads was 0.82 ± 0.17 (CI: 0.49, 1.16). In conclusion, training with loads ≤50% 1 RM was found to promote substantial increases in muscle strength and hypertrophy in untrained individuals, but a trend was noted for superiority of heavy loading with respect to these outcome measures with null findings likely attributed to a relatively small number of studies on the topic.

  13. High Efficiency Binding Aptamers for a Wide Range of Bacterial Sepsis Agents.

    Science.gov (United States)

    Graziani, Ana Cláudia; Stets, Maria Isabel; Lopes, Ana Luisa Kalb; Schluga, Pedro Henrique Caires; Marton, Soledad; Mendes, Ieda Ferreira; Andrade, Antero Silva Ribeiro de; Krieger, Marco Aurélio; Cardoso, Josiane

    2017-04-28

    Sepsis is a major health problem worldwide, with an extremely high rate of morbidity and mortality, partly due to delayed diagnosis during early disease. Currently, sepsis diagnosis requires bacterial culturing of blood samples over several days, whereas PCR-based molecular diagnosis methods are faster but lack sensitivity. The use of biosensors containing nucleic acid aptamers that bind targets with high affinity and specificity could accelerate sepsis diagnosis. Previously, we used the systematic evolution of ligands by exponential enrichment technique to develop the aptamers Antibac1 and Antibac2, targeting the ubiquitous bacterial peptidoglycan. Here, we show that these aptamers bind to four gram-positive and seven gram-negative bacterial sepsis agents with high binding efficiency. Thus, these aptamers could be used in combination as biological recognition elements in the development of biosensors that are an alternative to rapid bacteria detection, since they could provide culture and amplification-free tests for rapid clinical sepsis diagnosis.

  14. LOADS INFLUENCE ANALYSIS ON NOVEL HIGH PRECISION FLEXURE PARALLEL POSITIONER

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A large workspace flexure parallel positioner system is developed, which can attain sub-micron scale accuracy over cubic centimeter motion range for utilizing novel wide-range flexure hinges instead of the conventional mechanism joints. Flexure hinges eliminate backlash and friction, but on the other hand their deformation caused by initial loads influences the positioning accuracy greatly, so discussions about loads' influence analysis on this flexure parallel positioner is very necessary. The stiffness model of the whole mechanism is presented via stiffness assembly method based on the stiffness model of individual flexure hinge. And the analysis results are validated by the finite element analysis (FEA) simulation and experiment tests, which provide essential data to the practical application of this positioner system.

  15. Review of 20 years research in fatigue of high pressure loaded components

    Energy Technology Data Exchange (ETDEWEB)

    Thumser, Rayk [Bauhaus Univ. Weimar (Germany). Materialforschungs- und -pruefanstalt; Scheibe, Wolfgang

    2011-07-01

    This paper gives an overview of the research in fatigue of high pressure loaded components. In the last 20 years the main research was carried out in Germany. This research was mainly driven by the fatigue requirements for high pressure loaded Diesel engine injection parts as common rails, injectors and pipes. (orig.)

  16. Inflammation in the middle ear of children with recurrent or chronic otitis media is associated with bacterial load

    NARCIS (Netherlands)

    Stol, K.; Diavatopoulos, D.A.; Graamans, K.; Engel, J.A.; Melchers, W.J.G.; Savelkoul, H.F.J.; Hays, J.P.; Warris, A.; Hermans, P.W.M.

    2012-01-01

    Background: Viral upper respiratory tract infections have been described as an important factor in the development of otitis media (OM), although it is unclear whether they facilitate bacterial OM or can directly cause OM. To clarify the role of viral infections in OM, we compared the relative contr

  17. The co-occurrence of the demosponge Hymeniacidon perlevis and the edible mussel Mytilus galloprovincialis as a new tool for bacterial load mitigation in aquaculture.

    Science.gov (United States)

    Longo, Caterina; Cardone, Frine; Corriero, Giuseppe; Licciano, Margherita; Pierri, Cataldo; Stabili, Loredana

    2016-02-01

    filter-feeder H. perlevis with M. galloprovincialis is a powerful tool in reducing the bacterial load in shellfish culture areas thus playing a role in mitigating the health hazard related to the consumption of edible mussels.

  18. High-Resolution Melt Analysis for Rapid Comparison of Bacterial Community Compositions

    DEFF Research Database (Denmark)

    Hjelmsø, Mathis Hjort; Hansen, Lars Hestbjerg; Bælum, Jacob

    2014-01-01

    and fertilization treatments. The HRM analysis identified a shift in the bacterial community composition in two of the treatments, both including the soil fumigant Basamid GR. These results were confirmed with both denaturing gradient gel electrophoresis (DGGE) analysis and 454-based 16S rRNA gene amplicon......In the study of bacterial community composition, 16S rRNA gene amplicon sequencing is today among the preferred methods of analysis. The cost of nucleotide sequence analysis, including requisite computational and bioinformatic steps, however, takes up a large part of many research budgets. High......-resolution melt (HRM) analysis is the study of the melt behavior of specific PCR products. Here we describe a novel high-throughput approach in which we used HRM analysis targeting the 16S rRNA gene to rapidly screen multiple complex samples for differences in bacterial community composition. We hypothesized...

  19. A small-scale, low-cost isolation system for the incubation and rearing of low bacterial load chicks as a model to study microbial-intestinal interactions.

    Science.gov (United States)

    Forder, Rebecca E A; Firth, Gordon A; Tivey, David R; Howarth, Gordon S; Hughes, Robert J

    2008-04-01

    A small-scale, economical isolator system was adapted to hatch and raise chicks in a bacteria-free environment as a means to observe bacterial interactions with the intestinal mucosa during early development. The design and construction of flexible plastic isolators for incubation and brooding are described along with methodologies for preparation of eggs for entry into the isolators, incubation and hatching. Two trials were conducted, the first in August 2005 and the second in March 2006. Results from both trials showed no differences in body weights of chicks raised in isolation when compared with those raised conventionally. Growth of bacteria was detected from rectal swabs at day 2 post-hatch, with both trials, showing a light growth of Bacillus sp., coagulase-negative staphylococci and haemolytic streptococcus in trial 1, and a light growth of Bacillus cereus only in trial 2. Although not germfree, the growth of bacteria in chicks raised in isolation was decreased or absent when compared with chicks raised conventionally. Feed was negative for contamination and surface swabs of equipment were also negative until day 3 post-hatch, suggesting possible contamination within the eggs themselves. Despite the presence of bacterial species, the isolator system was successful in producing low bacterial load chicks for comparison studies with conventionally raised chicks.

  20. Gearbox Reliability Collaborative Investigation of High-Speed-Shaft Bearing Loads

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    The loads and contact stresses in the bearings of the high speed shaft section of the Gearbox Reliability Collaborative gearbox are examined in this paper. The loads were measured though strain gauges installed on the bearing outer races during dynamometer testing of the gearbox. Loads and stresses were also predicted with a simple analytical model and higher-fidelity commercial models. The experimental data compared favorably to each model, and bearing stresses were below thresholds for contact fatigue and axial cracking.

  1. Potent engineered PLGA nanoparticles by virtue of exceptionally high chemotherapeutic loadings.

    Science.gov (United States)

    Enlow, Elizabeth M; Luft, J Christopher; Napier, Mary E; DeSimone, Joseph M

    2011-02-01

    Herein we report the fabrication of engineered poly(lactic acid-co-glycolic acid) nanoparticles via the PRINT (particle replication in nonwetting templates) process with high and efficient loadings of docetaxel, up to 40% (w/w) with encapsulation efficiencies >90%. The PRINT process enables independent control of particle properties leading to a higher degree of tailorability than traditional methods. Particles with 40% loading display better in vitro efficacy than particles with lower loadings and the clinical formulation of docetaxel, Taxotere.

  2. The source of high signal cooperativity in bacterial chemosensory arrays.

    Science.gov (United States)

    Piñas, Germán E; Frank, Vered; Vaknin, Ady; Parkinson, John S

    2016-03-22

    The Escherichia coli chemosensory system consists of large arrays of transmembrane chemoreceptors associated with a dedicated histidine kinase, CheA, and a linker protein, CheW, that couples CheA activity to receptor control. The kinase activity responses to receptor ligand occupancy changes can be highly cooperative, reflecting allosteric coupling of multiple CheA and receptor molecules. Recent structural and functional studies have led to a working model in which receptor core complexes, the minimal units of signaling, are linked into hexagonal arrays through a unique interface 2 interaction between CheW and the P5 domain of CheA. To test this array model, we constructed and characterized CheA and CheW mutants with amino acid replacements at key interface 2 residues. The mutant proteins proved defective in interface 2-specific in vivo cross-linking assays, and formed signaling complexes that were dispersed around the cell membrane rather than clustered at the cell poles as in wild type chemosensory arrays. Interface 2 mutants down-regulated CheA activity in response to attractant stimuli in vivo, but with much less cooperativity than the wild type. Moreover, mutant cells containing fluorophore-tagged receptors exhibited greater basal anisotropy that changed rapidly in response to attractant stimuli, consistent with facile changes in loosely packed receptors. We conclude that interface 2 lesions disrupt important network connections between core complexes, preventing receptors from operating in large, allosteric teams. This work confirms the critical role of interface 2 in organizing the chemosensory array, in directing the clustered array to the cell poles, and in producing its highly cooperative signaling properties.

  3. Progressive high-load strength training compared with general low-load exercises in patients with rotator cuff tendinopathy

    DEFF Research Database (Denmark)

    Ingwersen, Kim G; Christensen, Robin; Sørensen, Lilli

    2015-01-01

    subgroups of SIS and have often had methodological flaws, making it difficult to specifically design target treatment for patients diagnosed with SIS. Therefore, it was considered important to focus on a subgroup such as tendinopathy, with a specific tailored intervention strategy based on evidence from...... of this trial is to compare the efficacy of progressive high-load exercises with traditional low-load exercises in patients with rotator cuff tendinopathy. Methods/Design: The current study is a randomised, participant- and assessor-blinded, controlled multicentre trial. A total of 260 patients with rotator...... home-based exercises three times a week. The primary outcome measure will be change from baseline to 12 weeks in the patient-reported outcome Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Discussion: Previous studies of exercise treatment for SIS have not differentiated between...

  4. Three Months of Progressive High-Load Versus Traditional Low-Load Strength Training Among Patients With Rotator Cuff Tendinopathy

    DEFF Research Database (Denmark)

    Ingwersen, Kim Gordon; Jensen, Steen Lund; Sørensen, Lilli

    2017-01-01

    BACKGROUND: Progressive high-load exercise (PHLE) has led to positive clinical results in patients with patellar and Achilles tendinopathy. However, its effects on rotator cuff tendinopathy still need to be investigated. PURPOSE: To assess the clinical effects of PHLE versus low-load exercise (LLE......) among patients with rotator cuff tendinopathy. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Patients with rotator cuff tendinopathy were recruited and randomized to 12 weeks of PHLE or LLE, stratified for concomitant administration of corticosteroid injection. The primary...... benefit from PHLE over traditional LLE among patients with rotator cuff tendinopathy. Further investigation of the possible interaction between exercise type and corticosteroid injection is needed to establish optimal and potentially synergistic combinations of these 2 factors. REGISTRATION: NCT01984203...

  5. Effects of laxative and N-acetylcysteine on mucus accumulation, bacterial load, transit, and inflammation in the cystic fibrosis mouse small intestine.

    Science.gov (United States)

    De Lisle, Robert C; Roach, Eileen; Jansson, Kyle

    2007-09-01

    The accumulation of mucus in affected organs is characteristic of cystic fibrosis (CF). The CF mouse small intestine has dramatic mucus accumulation and exhibits slower interdigestive intestinal transit. These factors are proposed to play cooperative roles that foster small intestinal bacterial overgrowth (SIBO) and contribute to the innate immune response of the CF intestine. It was hypothesized that decreasing the mucus accumulation would reduce SIBO and might improve other aspects of the CF intestinal phenotype. To test this, solid chow-fed CF mice were treated with an osmotic laxative to improve gut hydration or liquid-fed mice were treated orally with N-acetylcysteine (NAC) to break mucin disulfide bonds. Treatment with laxative or NAC reduced mucus accumulation by 43% and 50%, respectively, as measured histologically as dilation of the intestinal crypts. Laxative and NAC also reduced bacterial overgrowth in the CF intestine by 92% and 63%, respectively. Treatment with laxative normalized small intestinal transit in CF mice, whereas NAC did not. The expression of innate immune response-related genes was significantly reduced in laxative-treated CF mice, whereas there was no significant effect in NAC-treated CF mice. In summary, laxative and NAC treatments of CF mice reduced mucus accumulation to a similar extent, but laxative was more effective than NAC at reducing bacterial load. Eradication of bacterial overgrowth by laxative treatment was associated with normalized intestinal transit and a reduction in the innate immune response. These results suggest that both mucus accumulation and slowed interdigestive small intestinal transit contribute to SIBO in the CF intestine.

  6. Association between BVAB1 and high Nugent scores among women with bacterial vaginosis

    Science.gov (United States)

    Muzny, Christina A.; Sunesara, Imran R.; Griswold, Michael E.; Kumar, Ranjit; Lefkowitz, Elliot J.; Mena, Leandro A.; Schwebke, Jane R.; Martin, David H.; Swiatlo, Edwin

    2015-01-01

    As part of a larger study using 454 pyrosequencing to investigate the vaginal microbiota of women with bacterial vaginosis (BV), we found an association between a novel BV-associated bacterium (BVAB1) and high Nugent scores and propose that BVAB1 is the curved Gram-negative rod traditionally identified as Mobiluncus spp. in vaginal Gram stains. PMID:25262105

  7. Association between BVAB1 and high Nugent scores among women with bacterial vaginosis.

    Science.gov (United States)

    Muzny, Christina A; Sunesara, Imran R; Griswold, Michael E; Kumar, Ranjit; Lefkowitz, Elliot J; Mena, Leandro A; Schwebke, Jane R; Martin, David H; Swiatlo, Edwin

    2014-12-01

    As part of a larger study using 454 pyrosequencing to investigate the vaginal microbiota of women with bacterial vaginosis (BV), we found an association between a novel BV-associated bacterium (BVAB1) and high Nugent scores and propose that BVAB1 is the curved Gram-negative rod traditionally identified as Mobiluncus spp. in vaginal Gram stains.

  8. Rapid detection of malto-oligosaccharide-forming bacterial amylases by high performance anion-exchange chromatography

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Larsen, K. L.; Zimmermann, W.

    2000-01-01

    High performance anion-exchange chromatography with pulsed amperometric detection was applied for the rapid analysis of malto-oligosaccharides formed by extracellular enzyme preparations from 49 starch-degrading bacterial strains isolated from soil and compost samples. Malto-oligosaccharide-formi...

  9. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography.

    Science.gov (United States)

    Desmarais, Samantha M; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D; de Pedro, Miguel A; Huang, Kerwyn Casey

    2015-12-25

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination.

  10. High-throughput nucleotide sequence analysis of diverse bacterial communities in leachates of decomposing pig carcasses

    Directory of Open Access Journals (Sweden)

    Seung Hak Yang

    2015-09-01

    Full Text Available The leachate generated by the decomposition of animal carcass has been implicated as an environmental contaminant surrounding the burial site. High-throughput nucleotide sequencing was conducted to investigate the bacterial communities in leachates from the decomposition of pig carcasses. We acquired 51,230 reads from six different samples (1, 2, 3, 4, 6 and 14 week-old carcasses and found that sequences representing the phylum Firmicutes predominated. The diversity of bacterial 16S rRNA gene sequences in the leachate was the highest at 6 weeks, in contrast to those at 2 and 14 weeks. The relative abundance of Firmicutes was reduced, while the proportion of Bacteroidetes and Proteobacteria increased from 3–6 weeks. The representation of phyla was restored after 14 weeks. However, the community structures between the samples taken at 1–2 and 14 weeks differed at the bacterial classification level. The trend in pH was similar to the changes seen in bacterial communities, indicating that the pH of the leachate could be related to the shift in the microbial community. The results indicate that the composition of bacterial communities in leachates of decomposing pig carcasses shifted continuously during the study period and might be influenced by the burial site.

  11. Spatial Vulnerability: Bacterial Arrangements, Microcolonies, and Biofilms as Responses to Low Rather than High Phage Densities

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2012-04-01

    Full Text Available The ability of bacteria to survive and propagate can be dramatically reduced upon exposure to lytic bacteriophages. Study of this impact, from a bacterium’s perspective, tends to focus on phage-bacterial interactions that are governed by mass action, such as can be observed within continuous flow or similarly planktonic ecosystems. Alternatively, bacterial molecular properties can be examined, such as specific phage‑resistance adaptations. In this study I address instead how limitations on bacterial movement, resulting in the formation of cellular arrangements, microcolonies, or biofilms, could increase the vulnerability of bacteria to phages. Principally: (1 Physically associated clonal groupings of bacteria can represent larger targets for phage adsorption than individual bacteria; and (2, due to a combination of proximity and similar phage susceptibility, individual bacteria should be especially vulnerable to phages infecting within the same clonal, bacterial grouping. Consistent with particle transport theory—the physics of movement within fluids—these considerations are suggestive that formation into arrangements, microcolonies, or biofilms could be either less profitable to bacteria when phage predation pressure is high or require more effective phage-resistance mechanisms than seen among bacteria not living within clonal clusters. I consider these ideas of bacterial ‘spatial vulnerability’ in part within a phage therapy context.

  12. Electronic system for high power load control. [solar arrays

    Science.gov (United States)

    Miller, E. L. (Inventor)

    1980-01-01

    Parallel current paths are divided into two groups, with control devices in the current paths of one group each having a current limiting resistor, and the control devices in the other group each having no limiting resistor, so that when the control devices of the second group are turned fully on, a short circuit is achieved by the arrangement of parallel current paths. Separate but coordinated control signals are provided to turn on the control devices of the first group and increase their conduction toward saturation as a function of control input, and when fully on, or shortly before, to turn on the control devices of the second group and increase their conduction toward saturation as a function of the control input as that input continues to increase. Electronic means may be used to generate signals. The system may be used for 1-V characteristic measurements of solar arrays as well as for other load control purposes.

  13. Maximum Likelihood Estimation of Time-Varying Loadings in High-Dimensional Factor Models

    DEFF Research Database (Denmark)

    Mikkelsen, Jakob Guldbæk; Hillebrand, Eric; Urga, Giovanni

    In this paper, we develop a maximum likelihood estimator of time-varying loadings in high-dimensional factor models. We specify the loadings to evolve as stationary vector autoregressions (VAR) and show that consistent estimates of the loadings parameters can be obtained by a two-step maximum...... likelihood estimation procedure. In the first step, principal components are extracted from the data to form factor estimates. In the second step, the parameters of the loadings VARs are estimated as a set of univariate regression models with time-varying coefficients. We document the finite...

  14. High heritability is compatible with the broad distribution of set point viral load in HIV carriers.

    Directory of Open Access Journals (Sweden)

    Sebastian Bonhoeffer

    2015-02-01

    Full Text Available Set point viral load in HIV patients ranges over several orders of magnitude and is a key determinant of disease progression in HIV. A number of recent studies have reported high heritability of set point viral load implying that viral genetic factors contribute substantially to the overall variation in viral load. The high heritability is surprising given the diversity of host factors associated with controlling viral infection. Here we develop an analytical model that describes the temporal changes of the distribution of set point viral load as a function of heritability. This model shows that high heritability is the most parsimonious explanation for the observed variance of set point viral load. Our results thus not only reinforce the credibility of previous estimates of heritability but also shed new light onto mechanisms of viral pathogenesis.

  15. Effect of High-pressure CO2 Processing on Bacterial Spores.

    Science.gov (United States)

    Rao, Lei; Bi, Xiufang; Zhao, Feng; Wu, Jihong; Hu, Xiaosong; Liao, Xiaojun

    2016-08-17

    High-pressure CO2 (HPCD) is a nonthermal technology that can effectively inactivate the vegetative forms of pathogenic and spoilage bacteria, yeasts, and molds at pressures less than 30 MPa and temperatures in the range of 20°C to 40°C. However, HPCD alone at moderate temperatures (20-40°C) is often insufficient to obtain a substantial reduction in bacterial spore counts because their structures are more complex than those of vegetative cells. In this review, we first thoroughly summarized and discussed the inactivation effect of HPCD treatment on bacterial spores. We then presented and discussed the kinetics by which bacterial spores are inactivated by HPCD treatment. We also summarized hypotheses drawn by different researchers to explain the mechanisms of spore inactivation by HPCD treatment. We then summarized the current research status and future challenges of spore inactivation by HPCD treatment.

  16. Nile Red Detection of Bacterial Hydrocarbons and Ketones in a High-Throughput Format

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, NM; Aukema, KG; Gralnick, JA; Wackett, LP

    2011-06-28

    A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones. IMPORTANCE In recent years, there has been renewed interest in advanced biofuel sources such as bacterial hydrocarbon production. Previous studies used solvent extraction of bacterial cultures followed by gas chromatography-mass spectrometry (GC-MS) to detect and quantify ketones and hydrocarbons (Beller HR, Goh EB, Keasling JD, Appl. Environ. Microbiol. 76: 1212-1223, 2010; Sukovich DJ, Seffernick JL, Richman JE, Gralnick JA, Wackett LP, Appl. Environ. Microbiol. 76: 3850-3862, 2010). While these analyses are powerful and accurate, their labor-intensive nature makes them intractable to high-throughput screening; therefore, methods for rapid identification of bacterial strains that are overproducing hydrocarbons are needed. The use of high

  17. Miniaturized MEMS-Based Gas Chromatograph for High Inertial Loads Associated with Planetary Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a rugged, miniaturized, low power MEMS-based gas chromatograph (GC) capable of handling the high inertial loads...

  18. Some important aspects in testing high-modulus fiber composite tubes designed for multiaxial loading.

    Science.gov (United States)

    Sullivan, T. L.; Chamis, C. C.

    1972-01-01

    Tubular specimens were potted in metal grips to determine the feasibility of this gripping method in applying multiaxial loads. Strain gage rosettes were used to assess grip transitional strains, through thickness strain variation and strain variations along the tube length and circumference. The investigation was limited to loading 0, 45, plus or minus 45, and 90 deg graphite/epoxy and glass/epoxy tubes in axial tension. Results include modifications made to the grips to reduce transitional strains, illustrations of the tube failure modes, and some material properties. The gripping concept shows promise as a satisfactory technique for applying multiaxial loads to high-strength, high-modulus fiber composite tubes.

  19. Use of quantitative 16S rRNA PCR to determine bacterial load does not augment conventional cerebrospinal fluid (CSF) cultures among children undergoing treatment for CSF shunt infection☆,☆☆

    Science.gov (United States)

    Simon, Tamara D.; Van Yserloo, Brian; Nelson, Kevin; Gillespie, David; Jensen, Randy; McAllister, James P.; Riva-Cambrin, Jay; Stockmann, Chris; Daly, Judy A.; Blaschke, Anne J.

    2013-01-01

    The aim of this study was to develop a quantitative 16S rRNA assay for determination of bacterial nucleic acid load in cerebrospinal fluid (CSF) shunt infection and to compare quantitative 16S rRNA polymerase chain reaction (PCR) findings to those of conventional bacterial culture in patients treated for CSF shunt infection. We developed a quantitative 16S rRNA PCR assay that detected bacterial load across a range of 2.5 × 109 down to 2.5 × 104 16S copies/mL CSF under experimental conditions for numerous Gram-positive and Gram-negative organisms. However, when applied to archived CSF samples from 25 shunt infection episodes, correlations between positive bacterial culture and 16S rRNA levels were seen in only half of infections, and 16S rRNA levels dropped precipitously after an initial peak on the first day of sample collection. Bacterial load measured using 16S rRNA PCR does not provide sufficient information beyond bacterial culture to inform CSF shunt infection treatment. PMID:23953744

  20. Preparation of Multiwall Carbon Nanotubes-supported High Loading Platinum for Vehicular PEMFC Application

    Institute of Scientific and Technical Information of China (English)

    Bing ZHANG; Li Juan CHEN; Kai Yong GE; Yan Chuan GUO; Bi Xian PENG

    2005-01-01

    Multiwall carbon nanotube-supported Pt (Pt/MWNTs) catalysts with high dispersion and high loading of Pt were prepared by chemical reduction method and the loading of Pt got to 40wt%. The average diameter of Pt nanoparticles on MWNTs was about 3.5 nm. When the hydrogen and air were used as reactant gases for PEMFC, Pt/MWNTs catalysts showed significantly higher performance than the Pt/XC-72 (carbon black) catalysts.

  1. Nutrition Coupled with High-Load Traditional or Low-Load Blood Flow Restricted Exercise During Human Limb Suspension

    Science.gov (United States)

    Hackney, K. J.; Everett, M.; Ploutz-Snyder, L. L.

    2011-01-01

    High-load resistance exercise (HRE) and low-load blood flow restricted (BFR) exercise have demonstrated efficacy for attenuating unloading related muscle atrophy and dysfunction. In recreational exercisers, protein consumption immediately before and/or after exercise has been shown to increase the skeletal muscle anabolic response to resistance training. PURPOSE: To compare the skeletal muscle adaptations when chocolate milk intake was coupled with HRE or low-load BFR exercise [3 d/wk] during simulated lower limb weightlessness. METHODS: Eleven subjects were counterbalanced [based on age and gender] to HRE (31 +/- 14 yr, 170 +/- 13 cm, 71 +/- 18 kg, 2M/3W) or low-load BFR exercise (31 +/- 12 yr, 169 +/- 13 cm, 66 +/- 14 kg, 2M/4W) during 30 days of unilateral lower limb suspension (ULLS). Both HRE and BFR completed 3 sets of single leg press and calf raise exercise during ULLS. BFR exercise intensity was 20% of repetition maximum (1RM) with a cuff inflation pressure of 1.3 systolic blood pressure (143 4 mmHg). Cuff pressure was maintained during all 3 sets including rest intervals (90s). HRE intensity was 75% 1RM and was performed without cuff inflation. Immediately (chocolate milk (150 kcal, 2.5g total fat, 22g total carbohydrate, 8g protein) was consumed to optimize acute exercise responses in favor of muscle anabolism. ULLS analog compliance was assessed from leg skin temperature recordings and plantar accelerometry. Muscle cross-sectional area (CSA) for knee extensor and plantar flexor muscle groups were determined from analysis of magnetic resonance images using ImageJ software. 1RM strength for leg press and calf raise was assessed on the Agaton exercise system. Muscular endurance during leg press and calf raise was evaluated from the maximal number of repetitions performed to volitional fatigue using 40% of pre-ULLS 1RM. RESULTS: Steps detected by plantar acceleometry declined by 98.9% during ULLS relative to an ambulatory control period. Average skin

  2. Resistance and resilience of removal efficiency and bacterial community structure of gas biofilters exposed to repeated shock loads.

    Science.gov (United States)

    Cabrol, Léa; Malhautier, Luc; Poly, Franck; Roux, Xavier Le; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis

    2012-11-01

    Since full-scale biofilters are often operated under fluctuating conditions, it is critical to understand their response to transient states. Four pilot-scale biofilters treating a composting gas mixture and undergoing repeated substrate pulses of increasing intensity were studied. A systematic approach was proposed to quantify the resistance and resilience capacity of their removal efficiency, which enabled to distinguish between recalcitrant (ammonia, DMDS, ketones) and easily degradable (esters and aldehyde) compounds. The threshold of disturbing shock intensity and the influence of disturbance history depended on the contaminant considered. The spatial and temporal distribution of the bacterial community structure in response to the perturbation regime was analysed by Denaturing Gradient Gel Electrophoresis (DGGE). Even if the substrate-pulses acted as a driving force for some community characteristics (community stratification), the structure-function relationships were trickier to evidence: the distributions of resistance and composition were only partially coupled, with contradictory results depending on the contaminant considered.

  3. Nonequivalence of membrane voltage and ion-gradient as driving forces for the bacterial flagellar motor at low load.

    Science.gov (United States)

    Lo, Chien-Jung; Leake, Mark C; Pilizota, Teuta; Berry, Richard M

    2007-07-01

    Many bacterial species swim using flagella. The flagellar motor couples ion flow across the cytoplasmic membrane to rotation. Ion flow is driven by both a membrane potential (V(m)) and a transmembrane concentration gradient. To investigate their relation to bacterial flagellar motor function we developed a fluorescence technique to measure V(m) in single cells, using the dye tetramethyl rhodamine methyl ester. We used a convolution model to determine the relationship between fluorescence intensity in images of cells and intracellular dye concentration, and calculated V(m) using the ratio of intracellular/extracellular dye concentration. We found V(m) = -140 +/- 14 mV in Escherichia coli at external pH 7.0 (pH(ex)), decreasing to -85 +/- 10 mV at pH(ex) 5.0. We also estimated the sodium-motive force (SMF) by combining single-cell measurements of V(m) and intracellular sodium concentration. We were able to vary the SMF between -187 +/- 15 mV and -53 +/- 15 mV by varying pH(ex) in the range 7.0-5.0 and extracellular sodium concentration in the range 1-85 mM. Rotation rates for 0.35-microm- and 1-microm-diameter beads attached to Na(+)-driven chimeric flagellar motors varied linearly with V(m). For the larger beads, the two components of the SMF were equivalent, whereas for smaller beads at a given SMF, the speed increased with sodium gradient and external sodium concentration.

  4. A criterion for high-cycle fatigue life and fatigue limit prediction in biaxial loading conditions

    Institute of Scientific and Technical Information of China (English)

    ukasz Pejkowski; Dariusz Skibicki

    2016-01-01

    This paper presents a criterion for high-cycle fatigue life and fatigue strength estimation under periodic proportional and non-proportional cyclic loading. The cri-terion is based on the mean and maximum values of the second invariant of the stress deviator. Important elements of the criterion are: function of the non-proportionality of fatigue loading and the materials parameter that expresses the materials sensitivity to non-proportional loading. The methods for the materials parameters determination uses three S–N curves: tension–compression, torsion, and any non-proportional loading proposed. The criterion has been verified using experimental data, and the results are included in the paper. These results should be considered as promis-ing. The paper also includes a proposal for multiaxial fatigue models classification due to the approach for the non-proportionality of loading.

  5. Surface modifications of W divertor components for EAST during exposure to high heat loads with He

    Energy Technology Data Exchange (ETDEWEB)

    Li, C., E-mail: lichun10@mails.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Greuner, H. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Yuan, Y. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhao, S.X.; Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Böswirth, B. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Fu, B.Q.; Jia, Y.Z. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, X. [Southwestern Institute of Physics, Chengdu, Sichuan 610041 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-08-15

    Flat-type W/Cu plasma-facing components have been developed for the new generation divertor of the Chinese Experimental Advanced Superconducting Tokamak. Surface modifications of such actively water-cooled W components following short and long pulse high heat loading coupled with He particle loads with fluence of 3 × 10{sup 22} m{sup −2} have been investigated. An adiabatically loaded W block was investigated as a comparison and exposed to short pulse loads. Blistering was observed on all sample surfaces, but was less pronounced on the components than on the W block, due to the significant lower surface temperature caused by active cooling. For components, longer pulse loads gave rise to a rougher surface. Furthermore, most blisters on components are found to be less than 1 μm in diameter, with just a very few blisters larger than 1 μm, observed only in some near 〈1 1 1〉 grains.

  6. Safe-site effects on rhizosphere bacterial communities in a high-altitude alpine environment.

    Science.gov (United States)

    Ciccazzo, Sonia; Esposito, Alfonso; Rolli, Eleonora; Zerbe, Stefan; Daffonchio, Daniele; Brusetti, Lorenzo

    2014-01-01

    The rhizosphere effect on bacterial communities associated with three floristic communities (RW, FI, and M sites) which differed for the developmental stages was studied in a high-altitude alpine ecosystem. RW site was an early developmental stage, FI was an intermediate stage, M was a later more matured stage. The N and C contents in the soils confirmed a different developmental stage with a kind of gradient from the unvegetated bare soil (BS) site through RW, FI up to M site. The floristic communities were composed of 21 pioneer plants belonging to 14 species. Automated ribosomal intergenic spacer analysis showed different bacterial genetic structures per each floristic consortium which differed also from the BS site. When plants of the same species occurred within the same site, almost all their bacterial communities clustered together exhibiting a plant species effect. Unifrac significance value (P < 0.05) on 16S rRNA gene diversity revealed significant differences (P < 0.05) between BS site and the vegetated sites with a weak similarity to the RW site. The intermediate plant colonization stage FI did not differ significantly from the RW and the M vegetated sites. These results pointed out the effect of different floristic communities rhizospheres on their soil bacterial communities.

  7. Effect of surface roughness and sterilization on bacterial adherence to ultra-high molecular weight polyethylene.

    Science.gov (United States)

    Kinnari, T J; Esteban, J; Zamora, N; Fernandez, R; López-Santos, C; Yubero, F; Mariscal, D; Puertolas, J A; Gomez-Barrena, E

    2010-07-01

    Sterilization with ethylene oxide (EO) and gas plasma (GP) are well-known methods applied to ultra-high molecular weight polyethylene (UHMWPE) surfaces in the belief that they prevent major material changes caused by gamma irradiation. However, the influence of these surface sterilization methods on bacterial adherence to UHMWPE is unknown. UHMWPE samples with various degrees of roughness (0.3, 0.8 and 2.0 μm) were sterilized with either GP or EO. The variations in hydrophobicity, surface free energy and surface functional groups were investigated before and after sterilization. Sterilized samples were incubated with either Staphylococcus aureus or Staphylococcus epidermidis in order to study bacterial adherence to these materials. Fewer bacteria adhered to UHMWPE after sterilization with EO than after sterilization with GP, especially to the smoothest surfaces. No changes in chemical composition of the UHMWPE surface due to sterilization were observed using X-ray photoemission spectroscopy analysis. The decreased bacterial adherence to UHMWPE found at the smoothest surfaces after sterilization with EO was not directly related to changes in chemical composition. Increased bacterial adherence to rougher surfaces was associated with increased polar surface energy of EO-sterilized surfaces.

  8. Facile, High Quality Sequencing of Bacterial Genomes from Small Amounts of DNA

    Directory of Open Access Journals (Sweden)

    Momchilo Vuyisich

    2014-01-01

    Full Text Available Sequencing bacterial genomes has traditionally required large amounts of genomic DNA (~1 μg. There have been few studies to determine the effects of the input DNA amount or library preparation method on the quality of sequencing data. Several new commercially available library preparation methods enable shotgun sequencing from as little as 1 ng of input DNA. In this study, we evaluated the NEBNext Ultra library preparation reagents for sequencing bacterial genomes. We have evaluated the utility of NEBNext Ultra for resequencing and de novo assembly of four bacterial genomes and compared its performance with the TruSeq library preparation kit. The NEBNext Ultra reagents enable high quality resequencing and de novo assembly of a variety of bacterial genomes when using 100 ng of input genomic DNA. For the two most challenging genomes (Burkholderia spp., which have the highest GC content and are the longest, we also show that the quality of both resequencing and de novo assembly is not decreased when only 10 ng of input genomic DNA is used.

  9. Safe-Site Effects on Rhizosphere Bacterial Communities in a High-Altitude Alpine Environment

    Directory of Open Access Journals (Sweden)

    Sonia Ciccazzo

    2014-01-01

    Full Text Available The rhizosphere effect on bacterial communities associated with three floristic communities (RW, FI, and M sites which differed for the developmental stages was studied in a high-altitude alpine ecosystem. RW site was an early developmental stage, FI was an intermediate stage, M was a later more matured stage. The N and C contents in the soils confirmed a different developmental stage with a kind of gradient from the unvegetated bare soil (BS site through RW, FI up to M site. The floristic communities were composed of 21 pioneer plants belonging to 14 species. Automated ribosomal intergenic spacer analysis showed different bacterial genetic structures per each floristic consortium which differed also from the BS site. When plants of the same species occurred within the same site, almost all their bacterial communities clustered together exhibiting a plant species effect. Unifrac significance value (P<0.05 on 16S rRNA gene diversity revealed significant differences (P<0.05 between BS site and the vegetated sites with a weak similarity to the RW site. The intermediate plant colonization stage FI did not differ significantly from the RW and the M vegetated sites. These results pointed out the effect of different floristic communities rhizospheres on their soil bacterial communities.

  10. Highly Loaded Fan by Using Tandem Cascade Rotor Blade

    Science.gov (United States)

    Hasegawa, Hiroaki; Suga, Shinya; Matsuoka, Akinori

    For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could be built. The design of fan with tandem cascades and the fan testing were carried out to develop the high pressure ratio fan for the Air Turbo Ramjet (ATR) propulsion system. The ATR is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds. In particular, high fan pressure ratio contributes to increase the engine thrust during subsonic flight at which the engine does not make use of ram effect. The results of the fan testing indicate that the pressure ratio of 2.2 is achieved in single stage fan.

  11. Exfoliation rate of mammary epithelial cells in milk on bovine mastitis caused by Staphylococcus aureus is associated with bacterial load.

    Science.gov (United States)

    Nagasawa, Yuya; Kiku, Yoshio; Sugawara, Kazue; Tanabe, Fuyuko; Hayashi, Tomohito

    2017-09-11

    The exfoliation rate of mammary epithelial cells (MECs) in milk is affected by physiological, breeding and environmental factors. Little is known about the relationship between the MEC exfoliation into milk and mammary-infected Staphylococcus aureus (S. aureus) load on bovine mastitis caused by S. aureus. The aim of this study was to investigate the relationship between S. aureus load and the proportion of MEC exfoliation in milk using five substantial bovine mastitis models. In 64 randomly extracted milk samples from udders at 3-21 days after S. aureus infusion, there were various samples with different numbers of S. aureus counts and somatic cell counts. No significant correlations were found between the S. aureus counts and somatic cell count (r = 0.338). In contrast, a significant correlation was noted between S. aureus counts and the proportion of cytokeratin-positive cells in the milk from the infused udders (r = 0.734, P S. aureus may contribute to reduced milk yield. © 2017 Japanese Society of Animal Science.

  12. Hybrid Superconducting Magnetic Bearing (HSMB) for high load devices

    Science.gov (United States)

    McMichael, C. K.; Ma, K. B.; Lamb, M. A.; Lin, M. W.; Chow, L.; Meng, R. L.; Hor, P. H.; Chu, W. K.

    1992-05-01

    Lifting capacities greater than 41 N/cm(exp 2) (60 psi) at 77 K have been achieved with a new type of levitation (hybrid) using a combination of permanent magnets and high quality melt-mixtured YBa2Cu3O(7-delta) (YBCO). The key concept of the hybrid superconducting magnetic bearing (HSMB) is the use of strong magnetic repulsion and attraction from permanent magnets for high levitation or suspension forces in conjunction with a superconductor's flux pinning characteristics to counteract the inherent instabilities in a system consisting of magnets only. To illustrate this concept, radial and axial forces between magnet/superconductor, magnet/magnet, and magnet/superconductor/magnet, were measured and compared for the thrust bearing configuration

  13. Mesoscale modeling of metal-loaded high explosives

    Energy Technology Data Exchange (ETDEWEB)

    Bdzil, John Bohdan [Los Alamos National Laboratory; Lieberthal, Brandon [UNIV OF ILLINOIS; Srewart, Donald S [UNIV OF ILLINOIS

    2010-01-01

    We describe a 3D approach to modeling multi-phase blast explosive, which is primarily condensed explosive by volume with inert embedded particles. These embedded particles are uniform in size and placed on the array of a regular lattice. The asymptotic theory of detonation shock dynamics governs the detonation shock propagation in the explosive. Mesoscale hydrodynamic simulations are used to show how the particles are compressed, deformed, and accelerated by the high-speed detonation products flow.

  14. Large Differences in Bacterial Community Composition among Three Nearby Extreme Waterbodies of the High Andean Plateau.

    Science.gov (United States)

    Aguilar, Pablo; Acosta, Eduardo; Dorador, Cristina; Sommaruga, Ruben

    2016-01-01

    The high Andean plateau or Altiplano contains different waterbodies that are subjected to extreme fluctuations in abiotic conditions on a daily and an annual scale. The bacterial diversity and community composition of those shallow waterbodies is largely unexplored, particularly, of the ponds embedded within the peatland landscape (i.e., Bofedales). Here we compare the small-scale spatial variability (Altiplano peatland ponds represent a hitherto unknown source of microbial diversity.

  15. Dynamic Response of RPC-Filled Steel Tubular Columns with High Load Carrying Capacity Under Axial Impact Loading

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhimin; WU Ping'an; JIA Jianwei

    2008-01-01

    Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted, and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method.Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of columns were obtained.

  16. Evaluation of Surface Roughness and Bacterial Adhesion on Tooth Enamel Irradiated With High Intensity Lasers.

    Science.gov (United States)

    Nogueira, Ruchele D; Silva, Camilla B; Lepri, Cesar P; Palma-Dibb, Regina Guenka; Geraldo-Martins, Vinicius R

    2017-01-01

    The aim was to evaluate the surface roughness and bacterial adhesion on enamel irradiated with high intensity lasers, associated or not to a fluoride varnish. Eighty fragments of bovine enamel were equally divided in 8 groups (n=10). Group 1 was not treated and Group 2 received only a 5% fluoride varnish application. The other groups were irradiated with an Er:Cr:YSGG (8.92 J/cm2), an Nd:YAG (84.9 J/cm2) and a diode laser (199.04 J/cm2), associated or not to a 5% fluoride varnish. The surface roughness was measured before and after treatments. Afterward, all samples were incubated in a suspension of S. mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted by a stereoscope and the results were expressed in CFU/mm2. One-way ANOVA and the Tukey´s test compared the roughness data and the Student´s test compared the results obtained in the bacterial adhesion test (a=5%). The results showed that the irradiated samples without varnish presented the same roughness and the same bacterial adhesion that the non-irradiated samples. However, samples irradiated in the presence of fluoride varnish showed higher surface roughness and higher bacterial adhesion than the non-irradiated samples and those irradiated without varnish. Presence of pigments in the varnish increased the lasers' action on the enamel surface, which produced ablation in this hard tissue and significantly increased its surface roughness. For this reason, the enamel's susceptibility to bacterial adhesion was higher when the irradiation of the samples was made in presence of fluoride varnish.

  17. High-throughput, kingdom-wide prediction and annotation of bacterial non-coding RNAs.

    Directory of Open Access Journals (Sweden)

    Jonathan Livny

    Full Text Available BACKGROUND: Diverse bacterial genomes encode numerous small non-coding RNAs (sRNAs that regulate myriad biological processes. While bioinformatic algorithms have proven effective in identifying sRNA-encoding loci, the lack of tools and infrastructure with which to execute these computationally demanding algorithms has limited their utilization. Genome-wide predictions of sRNA-encoding genes have been conducted in less than 3% of all sequenced bacterial strains, leading to critical gaps in current annotations. The relative paucity of genome-wide sRNA prediction represents a critical gap in current annotations of bacterial genomes and has limited examination of larger issues in sRNA biology, such as sRNA evolution. METHODOLOGY/PRINCIPAL FINDINGS: We have developed and deployed SIPHT, a high throughput computational tool that utilizes workflow management and distributed computing to effectively conduct kingdom-wide predictions and annotations of intergenic sRNA-encoding genes. Candidate sRNA-encoding loci are identified based on the presence of putative Rho-independent terminators downstream of conserved intergenic sequences, and each locus is annotated for several features, including conservation in other species, association with one of several transcription factor binding sites and homology to any of over 300 previously identified sRNAs and cis-regulatory RNA elements. Using SIPHT, we conducted searches for putative sRNA-encoding genes in all 932 bacterial replicons in the NCBI database. These searches yielded nearly 60% of previously confirmed sRNAs, hundreds of previously annotated cis-encoded regulatory RNA elements such as riboswitches, and over 45,000 novel candidate intergenic loci. CONCLUSIONS/SIGNIFICANCE: Candidate loci were identified across all branches of the bacterial evolutionary tree, suggesting a central and ubiquitous role for RNA-mediated regulation among bacterial species. Annotation of candidate loci by SIPHT provides clues

  18. High Nutrient Load Increases Biostabilization of Sediment by Biofilms

    Science.gov (United States)

    Valentine, K.; Mariotti, G.

    2016-12-01

    Benthic biofilms, matrixes of microbial cells and their secretions, have been shown to stabilize sediment in coastal environments. While there have been numerous studies on the effects of nutrients on the ability of vascular plants to stabilize sediment, few studies have investigated how nutrients affect biofilm growth and their ability to stabilize sediment. Diatom-based biofilms were grown in laboratory experiments on a settled bed of bentonite clay, under a saline water column with varying amounts of nutrients. Erodibility at different stages of biofilm growth was measured using a Gust Erosion Microcosm System, which applied shear stresses from 0.05 to 0.6 Pa. Biofilms more than one week old decreased the erodibility of the sediments in all nutrient treatments compared to abiotic experiments. With high nutrients, the biofilm grew the fastest; the erodibility decreased within two weeks of biofilm growth and remained low for all applied shear stresses. After four weeks of biofilm growth, no erosion of sediment occurred even at the highest applied shear stress (0.6 Pa). With low nutrients the erodibility decreased within three weeks. With no nutrients the biofilms grew similarly to those with low nutrients; the erodibility decreased within three weeks under shear stresses 0.05-0.45 Pa, but the sediments were eroded under high shear stresses. Under low to moderate shear stresses (0.05-0.45 Pa), the total mass eroded by all experiments with biofilms was similar, suggesting that any amount of biofilm decreases erodibility at low shear stresses. In summary, high nutrients allow for faster biostabilization and for resistance to extreme shear stresses. These results suggest that eutrophication would not decrease the biofilm ability to stabilize muddy sediments in coastal environment.

  19. Modeling and Depletion Simulations for a High Flux Isotope Reactor Cycle with a Representative Experiment Loading

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Betzler, Ben [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Hirtz, Gregory John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Ilas, Germina [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Sunny, Eva [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division

    2016-09-01

    The purpose of this report is to document a high-fidelity VESTA/MCNP High Flux Isotope Reactor (HFIR) core model that features a new, representative experiment loading. This model, which represents the current, high-enriched uranium fuel core, will serve as a reference for low-enriched uranium conversion studies, safety-basis calculations, and other research activities. A new experiment loading model was developed to better represent current, typical experiment loadings, in comparison to the experiment loading included in the model for Cycle 400 (operated in 2004). The new experiment loading model for the flux trap target region includes full length 252Cf production targets, 75Se production capsules, 63Ni production capsules, a 188W production capsule, and various materials irradiation targets. Fully loaded 238Pu production targets are modeled in eleven vertical experiment facilities located in the beryllium reflector. Other changes compared to the Cycle 400 model are the high-fidelity modeling of the fuel element side plates and the material composition of the control elements. Results obtained from the depletion simulations with the new model are presented, with a focus on time-dependent isotopic composition of irradiated fuel and single cycle isotope production metrics.

  20. A method for calculation of finite fatigue life under multiaxial loading in high-cycle domain

    Directory of Open Access Journals (Sweden)

    M. Malnati

    2014-04-01

    Full Text Available A method for fatigue life assessment in high-cycle domain under multiaxial loading is presented in this paper. This approach allows fatigue assessment under any kind of load history, without limitations. The methodology lies on the construction - at a macroscopic level - of an “indicator” in the form of a set of cycles, representing plasticity that can arise at mesoscopic level throughout fatigue process. During the advancement of the loading history new cycles are created and a continuous evaluation of the damage is made.

  1. High-dose vaginal maintenance metronidazole for recurrent bacterial vaginosis: a pilot study.

    Science.gov (United States)

    Aguin, Tina; Akins, Robert A; Sobel, Jack D

    2014-05-01

    The purpose of this study was to explore the benefit of high-dose intravaginal metronidazole as a maintenance therapy in reducing recurrence rates of bacterial vaginosis (BV). Eighteen women with a history of recurrent BV and symptomatic BV were treated with metronidazole 750 mg suppository intravaginally daily for 7 days. Those in remission by Amsel criteria received metronidazole 750 mg twice weekly for 3 months with further follow-up for 3 months. High-dose metronidazole intravaginally was associated with rare clinical recurrence during the period of use. After cessation of suppression therapy, recurrence was high.

  2. Optimization of biomethanation focusing on high ammonia loaded processes

    DEFF Research Database (Denmark)

    Wang, Han

    , could theoretically mitigate the ammonia inhibition problem (Angelidaki et al., 1999). Therefore, the effect of co-digestion of cattle manure with lipids (i.e. glycerol trioleate (GTO)) under high ammonia levels (5 g NH4+-N·L-1) in anaerobic continuous stirred tank (CSTR) reactors (RGTO) was assessed....... Additionally, for comparison purposes, a soluble carbohydrate (i.e. glucose) was also used as a co-substrate in an identical CSTR reactor (RGLU). At 5 g NH4+-N·L-1, relative methane production of RGTO and RGLU, was 10.5% and 41% compared to the expected uninhibited production, respectively. At the same time...... control reactor (RCTL), only fed with manure, reached 32.7% compared to the uninhibited basis production. Therefore, the hypothesis that the co-digestion of manure with lipids could alleviate the ammonia inhibition was not supported by the results. However, an “ammonia-LCFA synergetic inhibitory effect...

  3. Gadolinium loaded plastic scintillators for high efficiency neutron detection

    Science.gov (United States)

    Ovechkina, Lena; Riley, Kent; Miller, Stuart; Bell, Zane; Nagarkar, Vivek

    2009-08-01

    Gadolinium has the highest thermal neutron absorption cross section of any naturally occurring element, and emits conversion electrons as well as atomic X-rays in over 50% of its neutron captures, which makes it a useful dopant in scintillators for detecting thermal neutrons. Gadolinium isopropoxide was studied as a possible dopant for styrene-based plastic scintillators as a convenient and inexpensive method to produce high-efficiency thermal neutron detectors. Plastic scintillators with gadolinium weight concentrations of up to 3% were transparent, uniform and defect-free and were characterized with spectral measurements performed under x-ray and neutron irradiation. The new material has the same characteristic emission of styrene with a maximum at approximately 425 nm, and a light output of 76% relative to the undoped plastic. A 13 mm thick sample containing 0.5% gadolinium by weight detected 46% of incident thermal neutrons, which makes this an attractive material for a variety of applications.

  4. High strain rate loading of polymeric foams and solid plastics

    Science.gov (United States)

    Dick, Richard D.; Chang, Peter C.; Fourney, William L.

    2000-04-01

    The split-Hopkinson pressure bar (SHPB) provided a technique to determine the high strain rate response for low density foams and solid ABS and polypropylene plastics. These materials are used in the interior safety panels of automobiles and crash test dummies. Because the foams have a very low impedance, polycarbonate bars were used to acquire the strain rate data in the 100 to 1600 l/s range. An aluminum SPHB setup was used to obtain the solid plastics data which covered strain rates of 1000 to 4000 l/s. The curves for peak strain rate versus peak stress for the foams over the test range studied indicates only a slight strain rate dependence. Peak strain rate versus peak stress curves for polypropylene shows a strain rate dependence up to about 1500 l/s. At that rate the solid poly propylene indicates no strain rate dependence. The ABS plastics are strain rate dependent up to 3500 l/s and then are independent at larger strain rates.

  5. CFD simulations of transient load change on a high head Francis turbine

    Science.gov (United States)

    Jakobsen, Ken-Robert G.; Aasved Holst, Martin

    2017-01-01

    Motivated by the importance of better understanding the structural integrity of high-head hydraulic turbines operating at intermittent conditions, complete 360º steady-state and transient simulations of a Francis turbine are presented in this paper. The main target of the work has been to investigate different numerical approaches such as mesh deformation for different operating conditions. Steady-state simulations were performed at the best efficiency point (BEP) and used as initial conditions for the transient simulations considering load rejection from BEP to part load (BEP2PL) and during load acceptance from BEP to high load (BEP2HL). Simulation results were compared with experimental data available for the Francis-99 project where close agreement was found for the mesh independent solution. The transient load analyses showed general trends in accordance with the measurement reports, especially for the pressure in vaneless space that is of high importance regarding RSI effects. Some deviations were identified for the net head at load rejection for which further investigations will be conducted. All CFD simulations were performed at model scale with ANSYS CFX v. 17 at either 96 or 120 cores (2.60 GHz). The immersed boundary technique was tested during the initial stages of the project, but had to be abandoned due to severe memory requirements. Pressure amplitudes and other instantaneous results were not considered.

  6. Entropy-driven spatial organization of highly confined polymers: Lessons for the bacterial chromosome

    Science.gov (United States)

    Jun, Suckjoon; Mulder, Bela

    2006-08-01

    Despite recent progress in visualization experiments, the mechanism underlying chromosome segregation in bacteria still remains elusive. Here we address a basic physical issue associated with bacterial chromosome segregation, namely the spatial organization of highly confined, self-avoiding polymers (of nontrivial topology) in a rod-shaped cell-like geometry. Through computer simulations, we present evidence that, under strong confinement conditions, topologically distinct domains of a polymer complex effectively repel each other to maximize their conformational entropy, suggesting that duplicated circular chromosomes could partition spontaneously. This mechanism not only is able to account for the spatial separation per se but also captures the major features of the spatiotemporal organization of the duplicating chromosomes observed in Escherichia coli and Caulobacter crescentus. bacterial chromosome segregation | Caulobacter crescentus | Escherichia coli | polymer physics

  7. Bacterial Glycosyltransferases: Challenges and opportunities of a highly diverse enzyme class toward tailoring natural products

    Directory of Open Access Journals (Sweden)

    Jochen eSchmid

    2016-02-01

    Full Text Available The enzyme subclass of glycosyltransferases (EC 2.4 currently comprises 97 families as specified by CAZy classification. One of their important roles is in the biosynthesis of disaccharides, oligosaccharides and polysaccharides by catalyzing the transfer of sugar moieties from activated donor molecules to other sugar molecules. In addition glycosyltransferases also catalyze the transfer of sugar moieties onto aglycons, which is of great relevance for the synthesis of many high value natural products. Bacterial glycosyltransferases show a higher sequence similarity in comparison to mammalian ones. Even when most glycosyltransferases are poorly explored, state of the art technologies, such as protein engineering, domain swapping or computational analysis strongly enhance our understanding and utilization of these very promising classes of proteins. This perspective article will focus on bacterial glycosyltransferases, especially on classification, screening and engineering strategies to alter substrate specificity. The future development in these fields as well as obstacles and challenges will be highlighted and discussed.

  8. Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.

    Science.gov (United States)

    Torcasio, Antonia; Jähn, Katharina; Van Guyse, Maarten; Spaepen, Pieter; Tami, Andrea E; Vander Sloten, Jos; Stoddart, Martin J; van Lenthe, G Harry

    2014-01-01

    Exposure to microgravity causes loss of lower body bone mass in some astronauts. Low-magnitude high-frequency loading can stimulate bone formation on earth. Here we hypothesized that low-magnitude high-frequency loading will also stimulate bone formation under microgravity conditions. Two groups of six bovine cancellous bone explants were cultured at microgravity on a Russian Foton-M3 spacecraft and were either loaded dynamically using a sinusoidal curve or experienced only a static load. Comparable reference groups were investigated at normal gravity. Bone structure was assessed by histology, and mechanical competence was quantified using μCT and FE modelling; bone remodelling was assessed by fluorescent labelling and secreted bone turnover markers. Statistical analyses on morphometric parameters and apparent stiffness did not reveal significant differences between the treatment groups. The release of bone formation marker from the groups cultured at normal gravity increased significantly from the first to the second week of the experiment by 90.4% and 82.5% in response to static and dynamic loading, respectively. Bone resorption markers decreased significantly for the groups cultured at microgravity by 7.5% and 8.0% in response to static and dynamic loading, respectively. We found low strain magnitudes to drive bone turnover when applied at high frequency, and this to be valid at normal as well as at microgravity. In conclusion, we found the effect of mechanical loading on trabecular bone to be regulated mainly by an increase of bone formation at normal gravity and by a decrease in bone resorption at microgravity. Additional studies with extended experimental time and increased samples number appear necessary for a further understanding of the anabolic potential of dynamic loading on bone quality and mechanical competence.

  9. Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.

    Directory of Open Access Journals (Sweden)

    Antonia Torcasio

    Full Text Available Exposure to microgravity causes loss of lower body bone mass in some astronauts. Low-magnitude high-frequency loading can stimulate bone formation on earth. Here we hypothesized that low-magnitude high-frequency loading will also stimulate bone formation under microgravity conditions. Two groups of six bovine cancellous bone explants were cultured at microgravity on a Russian Foton-M3 spacecraft and were either loaded dynamically using a sinusoidal curve or experienced only a static load. Comparable reference groups were investigated at normal gravity. Bone structure was assessed by histology, and mechanical competence was quantified using μCT and FE modelling; bone remodelling was assessed by fluorescent labelling and secreted bone turnover markers. Statistical analyses on morphometric parameters and apparent stiffness did not reveal significant differences between the treatment groups. The release of bone formation marker from the groups cultured at normal gravity increased significantly from the first to the second week of the experiment by 90.4% and 82.5% in response to static and dynamic loading, respectively. Bone resorption markers decreased significantly for the groups cultured at microgravity by 7.5% and 8.0% in response to static and dynamic loading, respectively. We found low strain magnitudes to drive bone turnover when applied at high frequency, and this to be valid at normal as well as at microgravity. In conclusion, we found the effect of mechanical loading on trabecular bone to be regulated mainly by an increase of bone formation at normal gravity and by a decrease in bone resorption at microgravity. Additional studies with extended experimental time and increased samples number appear necessary for a further understanding of the anabolic potential of dynamic loading on bone quality and mechanical competence.

  10. Fatigue in Welded High-Strength Steel Plate Elements under Stochastic Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

    1999-01-01

    The present project is a part of an investigation on fatigue in offshore structures in high-strength steel. The fatigue life of plate elements with welded attachments is studied. The material used has a yield stress of ~ 810-840 MPa, and high weldability and toughness properties. Fatigue test...... series with constant amplitude loading and with various types of stochastic loading have been carried through on test specimens in high-strength steel, and - for a comparison - on test specimens in conventional offshore structural steel with a yield stress of ~ 400-410 MPa.A comparison between constant...... amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those...

  11. High Pt Loading on Polydopamine Functionalized Graphene as a High Performance Cathode Electrocatalyst for Proton Exchange Membrane Fuel Cells

    OpenAIRE

    Monireh Faraji; Hussein Gharibi; Masoumeh Javaheri

    2016-01-01

    Morphology and size of platinum nanoparticles are a crucial factor in improving their catalytic activity and stability. Here, we firstly report the synthesis of high loading Pt nanoparticles on polydopamine reduced Graphene. The loading concentration of Pt (nanoparticles) NPs on Graphene can be adjusted in the range of 60-70%.With the insertion of polydopamine between Graphene oxide sheets, stacking of Graphene can be effectively prevented, promoting diffusion of oxygen molecules through the ...

  12. Similarity and cascade flow characteristics of a highly loaded helium compressor

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bin, E-mail: jiangbin_hrbeu@163.com [College of Power & Energy Engineering of Harbin Engineering University, Harbin 150001 (China); Chen, Zhongliang [College of Power & Energy Engineering of Harbin Engineering University, Harbin 150001 (China); Chen, Hang [AVIG Shenyang Engine Design and Research Institute, Shenyang 110015 (China); Zhang, Hai; Zheng, Qun [College of Power & Energy Engineering of Harbin Engineering University, Harbin 150001 (China)

    2015-05-15

    Highlights: • The deviation of different similarity criteria is analyzed theoretically. • Flow difference between helium and air compressor cascades is analyzed numerically. • The analysis of calculated results validates the theoretical derivation. • Flow characteristics of highly loaded helium compressor blade profile are computed. - Abstract: Helium compressor is a major component of the Power Conversion Unit (PCU) used in a High Temperature Gas Cooled Reactor (HTGR). Because the high cost of closed cycle test and leakage problem of helium gas, air could be used as working fluid instead of helium in compressor performance tests. However, the properties of Helium are largely different from those of air, e.g. the adiabatic exponent of Helium is 1.6, while the adiabatic exponent itself is a criterion of similarity between the two compressors. The characteristics of compressor will be different due to the effect of the adiabatic exponent of working fluid, especially for highly loaded compressor working at higher inlet Mach number. In this paper, a theoretical study on the similarity between air compressor and a highly loaded helium compressor is carried out and the deviation of similarity is analyzed. Numerical simulations are then used to confirm the theoretical analysis. The results indicate that the similarity deviation could not be neglected for highly loaded compressor cascade, which means the experience and experimental results of those conventional air compressor cannot be applied directly to the design of highly loaded helium compressor. The flow characteristics of a highly loaded helium compressor at different Reynolds numbers, attack angles, Mach numbers and cascade geometries are then investigated.

  13. An in vitro scratch tendon tissue injury model: effects of high frequency low magnitude loading.

    Science.gov (United States)

    Adekanmbi, Isaiah; Zargar, Nasim; Hulley, Philippa

    2017-03-01

    The healing process of ruptured tendons is suboptimal, taking months to achieve tissue with inferior properties to healthy tendon. Mechanical loading has been shown to positively influence tendon healing. However, high frequency low magnitude (HFLM) loads, which have shown promise in maintaining healthy tendon properties, have not been studied with in vitro injury models. Here, we present and validate an in vitro scratch tendon tissue injury model to investigate effects of HFLM loading on the properties of injured rat tail tendon fascicles (RTTFs). A longitudinal tendon tear was simulated using a needle aseptically to scratch a defined length along individual RTTFs. Tissue viability, biomechanical, and biochemical parameters were investigated before and 7 days after culture . The effects of static, HFLM (20 Hz), and low frequency (1 Hz) cyclic loading or no load were also investigated. Tendon viability was confirmed in damaged RTTFs after 7 days of culture, and the effects of a 0.77 ± 0.06 cm scratch on the mechanical property (tangent modulus) and tissue metabolism in damaged tendons were consistent, showing significant damage severity compared with intact tendons. Damaged tendon fascicles receiving HFLM (20 Hz) loads displayed significantly higher mean tangent modulus than unloaded damaged tendons (212.7 ± 14.94 v 92.7 ± 15.59 MPa), and damaged tendons receiving static loading (117.9 ± 10.65 MPa). HFLM stimulation maintained metabolic activity in 7-day cultured damaged tendons at similar levels to fresh tendons immediately following damage. Only damaged tendons receiving HFLM loads showed significantly higher metabolism than unloaded damaged tendons (relative fluorescence units -7021 ± 635.9 v 3745.1 ± 641.7). These validation data support the use of the custom-made in vitro injury model for investigating the potential of HFLM loading interventions in treating damaged tendons.

  14. Beyond perception: testing for implicit conceptual traces in high-load tasks.

    Science.gov (United States)

    Ruz, María; Fuentes, Luis J

    2009-09-01

    The present commentary addresses the main results obtained in the Butler and Klein [Butler, B. C., & Klein, R. (2009). Inattentional blindness for ignored words: Comparison of explicit and implicit memory tasks. Consciousness and Cognition, 18, 811-819.] study and discusses them in relation to the Perceptual Load Theory of Lavie [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451-68.]. The authors claim that the use of implicit indexes of conceptual distractor processing in high-load situations would be an important addition to the load literature, which would benefit the research field regardless of their positive or negative findings.

  15. Cockroaches as a Source of High Bacterial Pathogens with Multidrug Resistant Strains in Gondar Town, Ethiopia.

    Science.gov (United States)

    Moges, Feleke; Eshetie, Setegn; Endris, Mengistu; Huruy, Kahsay; Muluye, Dagnachew; Feleke, Tigist; G/Silassie, Fisha; Ayalew, Getenet; Nagappan, Raja

    2016-01-01

    Background. Cockroaches are source of bacterial infections and this study was aimed to assess bacterial isolates and their antimicrobial profiles from cockroaches in Gondar town, Ethiopia. Methods. A total of 60 cockroaches were collected from March 1 to May 30, 2014, in Gondar town. Bacterial species were isolated from external and internal parts of cockroaches. Disk diffusion method was used to determine antibiotic susceptibility patterns. Data were entered and analyzed by using SPSS version 20; P values cockroaches, respectively. Klebsiella pneumoniae 32 (17.7%), Escherichia coli 29 (16%), and Citrobacter spp. 27 (15%) were the predominant isolates. High resistance rate was observed to cotrimoxazole, 60 (33.1%), and least resistance rate was noted to ciprofloxacin, 2 (1.1%). Additionally, 116 (64.1%) of the isolates were MDR strains; Salmonella spp. were the leading MDR isolates (100%) followed by Enterobacter (90.5%) and Shigella spp. (76.9%). Conclusion. Cockroaches are the potential source of bacteria pathogens with multidrug resistant strains and hence effective preventive and control measures are required to minimize cockroach related infections.

  16. Intramammary Immunization of Pregnant Mice with Staphylococcal Protein A Reduces the Post-Challenge Mammary Gland Bacterial Load but Not Pathology.

    Directory of Open Access Journals (Sweden)

    Jully Gogoi-Tiwari

    Full Text Available Protein A, encoded by the spa gene, is one of the major immune evading MSCRAMM of S. aureus, demonstrated to be prevalent in a significant percentage of clinical bovine mastitis isolates in Australia. Given its' reported significance in biofilm formation and the superior performance of S. aureus biofilm versus planktonic vaccine in the mouse mastitis model, it was of interest to determine the immunogenicity and protective potential of Protein A as a potential vaccine candidate against bovine mastitis using the mouse mastitis model. Pregnant Balb/c mice were immunised with Protein A emulsified in an alum-based adjuvant by subcutaneous (s/c or intramammary (i/mam routes. While humoral immune response of mice post-immunization were determined using indirect ELISA, cell-mediated immune response was assessed by estimation of interferon-gamma (IFN-γ produced by protein A-stimulated splenocyte supernatants. Protective potential of Protein A against experimental mastitis was determined by challenge of immunized versus sham-vaccinated mice by i/mam route, based upon manifestation of clinical symptoms, total bacterial load and histopathological damage to mammary glands. Significantly (p<0.05 higher levels of IgG1 isotype were produced in mice immunized by the s/c route. In contrast, significantly higher levels of the antibody isotype IgG2a were produced in mice immunized by the i/mam route (p<0.05. There was significant reduction (p<0.05 in bacterial loads of the mammary glands of mice immunized by Protein A regardless of the route of immunization, with medium level of clinical symptoms observed up to day 3 post-challenge. However, Protein A vaccine failed to protect immunized mice post-challenge with biofilm producing encapsulated S. aureus via i/mam route, regardless of the route of immunization, as measured by the level of mammary tissue damage. It was concluded that, Protein A in its' native state was apparently not a suitable candidate for inclusion

  17. High Powered Tests of Dielectric Loaded High Pressure RF Cavities for Use in Muon Cooling Channels

    Energy Technology Data Exchange (ETDEWEB)

    Freemire, Ben [IIT, Chicago; Bowring, Daniel [Fermilab; Kochemirovskiy, Alexey [Chicago U.; Moretti, Alfred [Fermilab; Peterson, David [Fermilab; Tollestrup, Alvin [Fermilab; Torun, Yagmur [IIT, Chicago; Yonehara, Katsuya [Fermilab

    2016-06-01

    Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. Alumina of purities ranging from 96 to 99.8% was tested in a high pressure RF test cell at the MuCool Test Area at Fermilab. The results of breakdown studies with pure nitrogen gas, and oxygen-doped nitrogen gas indicate the peak surface electric field on the alumina ranges between 10 and 15 MV/m. How these results affect the design of a prototype cooling channel cavity will be discussed.

  18. Performance of rotating drum biofilter for volatile organic compound removal at high organic loading rates

    Institute of Scientific and Technical Information of China (English)

    YANG Chunping; CHEN Hong; ZENG Guangming; ZHU Xueqing; SUIDAN Makram T

    2008-01-01

    Uneven distribution of volatile organic compounds (VOCs) and biomass,and excess biomass accumulation in some biofilters hinder the application of biofiltration technology.An innovative multilayer rotating drum biofilter (RDB) was developed to correct these problems.The RDB was operated at an empty bed contact time (EBCT) of 30 s and a rotational rate of 1.0 r/rain.Diethyl ether was chosen as the model VOC.Performance of the RDB was evaluated at organic loading rates of 32.1,64.2,128,and 256 g ether/(m3·h) (16.06 g ether/(m3·h) ≈1.0 kg chemical oxygen demand (COD)/(m3·d)).The EBCT and organic loading rates were recorded on the basis of the medium volume.Results show that the ether removal efficiency decreased with an increased VOC loading rate.Ether removal efficiencies exceeding 99% were achieved without biomass control even at a high VOC loading rate of 128 g ether/(m3·h). However,when the VOC loading rate was increased to 256 g ether/(m3·h),the average removal efficiency dropped to 43%.Nutrient limitation possibly contributed to the drop in ether removal efficiency.High biomass accumulation rate was also observed in the medium at the two higher ether loading rates,and removal of the excess biomass in the media was necessary to maintain stable performance. This work showed that the RDB is effective in the removal of diethyl ether from waste gas streams even at high organic loading rates. The results might help establish criteria for designing and operating RDBs.

  19. Total protein or high-abundance protein: Which offers the best loading control for Western blotting?

    Science.gov (United States)

    Thacker, Jonathan S; Yeung, Derrick H; Staines, W Richard; Mielke, John G

    2016-03-01

    Western blotting routinely involves a control for variability in the amount of protein across immunoblot lanes. Normalizing a target signal to one found for an abundantly expressed protein is widely regarded as a reliable loading control; however, this approach is being increasingly questioned. As a result, we compared blotting for two high-abundance proteins (actin and glyceraldehyde 3-phosphate dehydrogenase [GAPDH]) and two total protein membrane staining methods (Ponceau and Coomassie Brilliant Blue) to determine the best control for loading variability. We found that Ponceau staining optimally balanced accuracy and precision, and we suggest that this approach be considered as an alternative to normalizing with a high-abundance protein.

  20. High-voltage transmission tower-line system subjected to disaster loads

    Institute of Scientific and Technical Information of China (English)

    LI Hongnan; BAI Haifeng

    2006-01-01

    The high-voltage power transmission system is an important lifeline structure. It is significant for wide researches on the features and ability of the system subjected to earthquake and environmental loads. The promising prosperity of the system has been demonstrated around the world. The corresponding advances of the system with respect to the mechanism of loading action, analytical methods, experimental research measurements, structural vibration control, fatigue damage, lifetime prediction, and design methods are comprehensively discussed herein. Finally, further research work on dynamic response characteristics of high-voltage transmission towerline system in the near future is predicted.

  1. Better target detection in the presence of collinear flankers under high working memory load

    Directory of Open Access Journals (Sweden)

    Jan W. De Fockert

    2014-10-01

    Full Text Available There are multiple ways in which working memory can influence selective attention. Aside from the content-specific effects of working memory on selective attention, whereby attention is more likely to be directed towards information that matches the contents of working memory, the mere level of load on working memory has also been shown to have an effect on selective attention. Specifically, high load on working memory is associated with increased processing of irrelevant information. In most demonstrations of the effect to-date, this has led to impaired target performance, leaving open the possibility that the effect partly reflects an increase in general task difficulty under high load. Here we show that working memory load can result in a performance gain when processing of distracting information aids target performance. The facilitation in the detection of a low-contrast Gabor stimulus in the presence of collinear flanking Gabors was greater when load on a concurrent working memory task was high, compared to low. This finding suggests that working memory can interact with selective attention at an early stage in visual processing.

  2. High-loading Fe2O3/SWNT composite films for lithium-ion battery applications

    Science.gov (United States)

    Wang, Ying; Guo, Jiahui; Li, Li; Ge, Yali; Li, Baojun; Zhang, Yingjiu; Shang, Yuanyuan; Cao, Anyuan

    2017-08-01

    Single-walled carbon nanotube (SWNT) films are a potential candidate as porous conductive electrodes for energy conversion and storage; tailoring the loading and distribution of active materials grafted on SWNTs is critical for achieving maximum performance. Here, we show that as-synthesized SWNT samples containing residual Fe catalyst can be directly converted to Fe2O3/SWNT composite films by thermal annealing in air. The mass loading of Fe2O3 nanoparticles is tunable from 63 wt% up to 96 wt%, depending on the annealing temperature (from 450 °C to 600 °C), while maintaining the porous network structure. Interconnected SWNT networks containing high-loading active oxides lead to synergistic effect as an anode material for lithium ion batteries. The performance is improved consistently with increasing Fe2O3 loading. As a result, our Fe2O3/SWNT composite films exhibit a high reversible capacity (1007.1 mA h g-1 at a current density of 200 mA g-1), excellent rate capability (384.9 mA h g-1 at 5 A g-1) and stable cycling performance with the discharge capacity up to 567.1 mA h g-1 after 600 cycles at 2 A g-1. The high-loading Fe2O3/SWNT composite films have potential applications as nanostructured electrodes for various energy devices such as supercapacitors and Li-ion batteries.

  3. Thermal shock behaviour of tungsten after high flux H-plasma loading

    Science.gov (United States)

    Wirtz, M.; Linke, J.; Pintsuk, G.; De Temmerman, G.; Wright, G. M.

    2013-11-01

    Previous studies have shown that transient thermal shock loads induce crack networks on tungsten samples especially at low base temperatures. To achieve test conditions which are more relevant for the performance of tungsten-armoured plasma facing components in next step thermonuclear fusion devices tungsten tiles were exposed to high flux hydrogen-plasma in the linear plasma generator Pilot-PSI and the high heat flux ion beam test facility MARION. Subsequently, the cyclic transient heat load tests were done in the electron beam facility JUDITH 1. The induced damages after these combined tests were examined by microscopically means, profilometry and metallography. The comparison of the obtained results and damage characteristics with those obtained after thermal shock loading show that the preloading of tungsten targets with high flux hydrogen-plasma has significant influence on the thermal shock behaviour of tungsten in terms of crack distance, width, and depth as well as cracked area. Furthermore the plasma parameters, in particular pulse duration and sample temperature during loading, have strong impact on the damage pattern after thermal shock loading.

  4. Muramic Acid Measurements for Bacterial Investigations in Marine Environments by High-Pressure Liquid Chromatography

    Science.gov (United States)

    Mimura, Toru; Romano, Jean-Claude

    1985-01-01

    Muramic acid, a constituent of procaryotic cell walls, was assayed by high-pressure liquid chromatography in samples from several marine environments (water column, surface microlayer, and sediment) and a bacterial culture. It is used as a microbial biomass indicator. The method gave a good separation of muramic acid from interfering compounds with satisfactory reproducibility. A pseudomonad culture had a muramic acid content of 4.7 × 10−10 to 5.3 × 10−10 μg per cell during growth. In natural water samples, highly significant relationships were found between muramic acid concentrations and bacterial numbers for populations of 108 to 1011 cells per liter. The muramic acid content in natural marine water decreased from 5.3 × 10−10 to 1.6 × 10−10 μg per cell with increasing depth. In coastal sediments exposed to sewage pollution, concentrations of muramic acid, ATP, organic carbon, and total amino acids displayed a parallel decrease with increasing distance from the sewage outlet. Advantages of muramic acid measurement by high-pressure liquid chromatography are its high sensitivity and reduction of preparation steps, allowing a short time analysis. PMID:16346848

  5. Change in the locus of dynamic loading axis on the knee joint after high tibial osteotomy.

    Science.gov (United States)

    Kawakami, Hideo; Sugano, Nobuhiko; Yonenobu, Kazuo; Yoshikawa, Hideki; Ochi, Takahiro; Nakata, Ken; Toritsuka, Yukiyoshi; Hattori, Asaki; Suzuki, Naoki

    2005-04-01

    The purpose of this study was to visualise the locus of the dynamic loading axis on the knee joint, and to evaluate changes in this locus during gait after high tibial osteotomy (HTO) in three patients who underwent HTO for medial compartment osteoarthritis (OA) of a varus knee. The bone structure of the lower limb and the relative position of skin markers were acquired from CT images. Motion capture data was acquired using spherical skin markers. Skeletal model movement during gait was calculated based on the movement of the markers. The locus of the dynamic loading axis on the knee joint was defined as the point on the proximal tibia joint surface that intersected with the loading axis of the lower limb, which passed through the centre of the femoral head and the centroid of multiple points surrounded by the distal tibia joint surface contour. This system was able to visualise the locus of the dynamic loading axis on the knee joint and not only lateral but also anterior-posterior direction movement. After HTO, the locus shifted from a medial and posterior area of the medial joint edge of the knee to a central area of the knee joint surface. This indicates that HTO shifted the dynamic loading axis. Lateral movement of the dynamic loading axis in the early stance phase of gait was reduced within a year after HTO.

  6. Stratified Bacterial Diversity along Physico-chemical Gradients in High-Altitude Modern Stromatolites

    Science.gov (United States)

    Toneatti, Diego M.; Albarracín, Virginia H.; Flores, Maria R.; Polerecky, Lubos; Farías, María E.

    2017-01-01

    At an altitude of 3,570 m, the volcanic lake Socompa in the Argentinean Andes is presently the highest site where actively forming stromatolite-like structures have been reported. Interestingly, pigment and microsensor analyses performed through the different layers of the stromatolites (50 mm-deep) showed steep vertical gradients of light and oxygen, hydrogen sulfide and pH in the porewater. Given the relatively good characterization of these physico-chemical gradients, the aim of this follow-up work was to specifically address how the bacterial diversity stratified along the top six layers of the stromatolites which seems the most metabolically important and diversified zone of the whole microbial community. We herein discussed how, in only 7 mm, a drastic succession of metabolic adaptations occurred: i.e., microbial communities shift from a UV-high/oxic world to an IR-low/anoxic/high H2S environment which force stratification and metabolic specialization of the bacterial community, thus, modulating the chemical faces of the Socompa stromatolites. The oxic zone was dominated by Deinococcus sp. at top surface (0.3 mm), followed by a second layer of Coleofasciculus sp. (0.3 to ∼2 mm). Sequences from anoxygenic phototrophic Alphaproteobacteria, along with an increasing diversity of phyla including Bacteroidetes, Spirochaetes were found at middle layers 3 and 4. Deeper layers (5–7 mm) were mostly occupied by sulfate reducers of Deltaproteobacteria, Bacteroidetes and Firmicutes, next to a high diversity and equitable community of rare, unclassified and candidate phyla. This analysis showed how microbial communities stratified in a physicochemical vertical profile and according to the light source. It also gives an insight of which bacterial metabolic capabilities might operate and produce a microbial cooperative strategy to thrive in one of the most extreme environments on Earth. PMID:28446906

  7. A FAST BIT-LOADING ALGORITHM FOR HIGH SPEED POWER LINE COMMUNICATIONS

    Institute of Scientific and Technical Information of China (English)

    Zhang Shengqing; Zhao Li; Zou Cairong

    2012-01-01

    Adaptive bit-loading is a key technology in high speed power line communications with the Orthogonal Frequency Division Multiplexing (OFDM) modulation technology.According to the real situation of the transmitting power spectrum limited in high speed power line communications,this paper explored the adaptive bit loading algorithm to maximize transmission bit number when transmitting power spectral density and bit error rate are not exceed upper limit.With the characteristics of the power line channel,first of all,it obtains the optimal bit loading algorithm,and then provides the improved algorithm to reduce the computational complexity.Based on the analysis and simulation,it offers a non-iterative bit allocation algorithm,and finally the simulation shows that this new algorithm can greatly reduce the computational complexity,and the actual bit allocation results close to optimal.

  8. The study of organic removal efficiency and halophilic bacterial mixed liquor characteristics in a membrane bioreactor treating hypersaline produced water at varying organic loading rates.

    Science.gov (United States)

    Sharghi, Elham Abdollahzadeh; Bonakdarpour, Babak

    2013-12-01

    In this study the organic pollutant removal performance and the mixed liquor characteristics of a membrane bioreactor (MBR), employing a halophilic bacterial consortium, for the treatment of hypersaline synthetic produced water - at varying organic loading rates (OLR) from 0.3 to 2.6 kg CODm(-3)d(-1) - were considered. The oil and grease (O&G) and COD removal efficiency were 95-99% and 83-93%, respectively with only transient O&G (mainly polycyclic aromatic hydrocarbons) and soluble microbial products accumulation being observed. With increasing OLR, in the range 0.9-2.6 kg COD m(-3)d(-1), as a result of change in both extracellular polymeric substances (EPS) and zeta potential, bioflocculating ability improved but the compressibility of the flocs decreased resulting in the occurrence of EPS bulking at the highest OLR studied. The latter resulted in a change in the rheology of the mixed liquor from Newtonian to non-Newtonian and the occurrence of significant membrane fouling. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Brittle materials at high-loading rates: an open area of research

    Science.gov (United States)

    Forquin, Pascal

    2017-01-01

    Brittle materials are extensively used in many civil and military applications involving high-strain-rate loadings such as: blasting or percussive drilling of rocks, ballistic impact against ceramic armour or transparent windshields, plastic explosives used to damage or destroy concrete structures, soft or hard impacts against concrete structures and so on. With all of these applications, brittle materials are subjected to intense loadings characterized by medium to extremely high strain rates (few tens to several tens of thousands per second) leading to extreme and/or specific damage modes such as multiple fragmentation, dynamic cracking, pore collapse, shearing, mode II fracturing and/or microplasticity mechanisms in the material. Additionally, brittle materials exhibit complex features such as a strong strain-rate sensitivity and confining pressure sensitivity that justify expending greater research efforts to understand these complex features. Currently, the most popular dynamic testing techniques used for this are based on the use of split Hopkinson pressure bar methodologies and/or plate-impact testing methods. However, these methods do have some critical limitations and drawbacks when used to investigate the behaviour of brittle materials at high loading rates. The present theme issue of Philosophical Transactions A provides an overview of the latest experimental methods and numerical tools that are currently being developed to investigate the behaviour of brittle materials at high loading rates. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  10. Brittle materials at high-loading rates: an open area of research

    Science.gov (United States)

    2017-01-01

    Brittle materials are extensively used in many civil and military applications involving high-strain-rate loadings such as: blasting or percussive drilling of rocks, ballistic impact against ceramic armour or transparent windshields, plastic explosives used to damage or destroy concrete structures, soft or hard impacts against concrete structures and so on. With all of these applications, brittle materials are subjected to intense loadings characterized by medium to extremely high strain rates (few tens to several tens of thousands per second) leading to extreme and/or specific damage modes such as multiple fragmentation, dynamic cracking, pore collapse, shearing, mode II fracturing and/or microplasticity mechanisms in the material. Additionally, brittle materials exhibit complex features such as a strong strain-rate sensitivity and confining pressure sensitivity that justify expending greater research efforts to understand these complex features. Currently, the most popular dynamic testing techniques used for this are based on the use of split Hopkinson pressure bar methodologies and/or plate-impact testing methods. However, these methods do have some critical limitations and drawbacks when used to investigate the behaviour of brittle materials at high loading rates. The present theme issue of Philosophical Transactions A provides an overview of the latest experimental methods and numerical tools that are currently being developed to investigate the behaviour of brittle materials at high loading rates. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956517

  11. Accumulative deformation in railway track induced by high-speed traffic loading of the trains

    Institute of Scientific and Technical Information of China (English)

    Bian Xuecheng; Jiang Hongguang; Chen Yunmin

    2010-01-01

    Prediction and control of the permanent settlement of a track caused by traffic loading from trains is crucial to high-speed railway design and maintenance. In this study, a unified prediction model of accumulative deformation of geomaterials used in railway construction subjected to cyclic loadings is introduced and calibrated using physical model testing. Based on this versatile model, a calculation approach to determine the track structure settlement under repeated loadings caused by the movement of the wheel axle of the train is proposed. Regression analysis on the physical model testing is adopted to determine the parameters involved in the computational approach. Comparison of model test data and computed results shows that the parameters obtained from the back-analysis are consistent throughout the various testing conditions, and the proposed calculation approach is capable of satisfactorily predicting the accumulative settlement of the railway roadbed and subgrade soil for various axle loads and loading cycles. A case study of a high-speed railway is performed to demonstrate the feasibility of the proposed approach in realistic engineering applications. The computation results from the settlement development of a roadbed and subgrade soil are presented and discussed.

  12. Biofilm and Planktonic Bacterial and Fungal Communities Transforming High-Molecular-Weight Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Folwell, Benjamin D; McGenity, Terry J; Whitby, Corinne

    2016-04-01

    High-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[a]pyrene (44% ± 13.6%) and benzo[b]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs were Pseudomonas, Bacillus, and Microbacterium species. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation.

  13. Material Compressing Test of the High Polymer Part Used in Draft Gear of Heavy Load Locomotive

    Directory of Open Access Journals (Sweden)

    Wei Yangang

    2016-01-01

    Full Text Available According to the actual load cases of heavy load locomotive, the material compressing tests of the high polymer parts used in the locomotive are researched. The relationship between stress and strain during the material compressing are acquired by means of comparing the many results of the material compressing tests under different test condition. The relationship between stress and strain during the material compressing is nonlinear in large range of strain, but the relationship is approximately linear in small range of strain. The material of the high polymer made in China and the material of the high polymer imported are compared through the tests. The results show that the compressing property of the material of the high polymer made in China and the material of the high polymer imported are almost same. The research offers the foundation to study the structure elasticity of the draft gear.

  14. Towards Cognitive-Aware Multimodal Presentation: The Modality Effects in High-Load HCI

    NARCIS (Netherlands)

    Cao, Yujia; Theune, Mariët; Nijholt, Anton; Harris, D,

    2009-01-01

    In this study, we argue that multimodal presentations should be created in a cognitive-aware manner, especially in a high-load HCI situation where the user task challenges the full capacity of the human cognition. An experiment was conducted to investigate the cognitive effects of modalities, using

  15. Influence of different SSF conditions on ethanol production from corn stover at high solids loadings

    DEFF Research Database (Denmark)

    Gladis, Arne; Bondesson, Pia-Maria; Galbe, Mats

    2015-01-01

    In this study, three different kinds of simultaneous saccharification and fermentation (SSF) of washed pretreated corn stover with water-insoluble solids (WIS) content of 20% were investigated to find which one resulted in highest ethanol yield at high-solids loadings. The different methods were...

  16. Fat oxidation before and after a high fat load in the obese insulin-resistant state

    NARCIS (Netherlands)

    Blaak, E.E.; Hul, G.; Verdich, C.; Stich, V.; Martinez, A.; Petersen, M.; Feskens, E.J.M.; Patel, K.; Oppert, J.M.; Barbe, P.; Toubro, S.; Anderson, I.; Polak, J.; Astrup, A.; Macdonald, I.A.; Holst, C.; Sørensen, T.I.; Saris, W.H.

    2006-01-01

    Background: Obesity may be associated with a lowered use of fat as a fuel, which may contribute to the enlarged adipose tissue stores. Aim: The aim of the present study was to study fatty acid use in the fasting state and in response to a high fat load in a large cohort of obese subjects (n = 701) a

  17. A high-rate shape memory alloy actuator for aerodynamic load control on wind turbines

    NARCIS (Netherlands)

    Lara-Quintanilla, A.; Hulskamp, A.W.; Bersee, H.E.N.

    2013-01-01

    This paper discusses the development of a high rate shape memory alloy (SMA) driven actuator. The concept of the actuator was developed to act as aerodynamic load control surface on wind turbines. It was designed as a plate or beam-like structure with prestrained SMA wires embedded off its neutral a

  18. Residual stress in a M3:2 PM high speed steel; effect of mechanical loading

    DEFF Research Database (Denmark)

    Højerslev, Christian; Odén, Magnus; Carstensen, Jesper V.;

    2001-01-01

    X-ray lattice strains were investigated in an AISI M3:2 PM high-speed steel in the as heat treated condition and after exposure to alternating mechanical load. The volume changes during heat treatment were monitored with dilatometry. Hardened and tempered AISI M3:2 steel consists of tempered lath...

  19. High HPV 16 viral load is associated with increased cervical dysplasia in Honduran women.

    NARCIS (Netherlands)

    Tabora, N.; Ferrera, A.; Bakkers, J.M.J.E.; Massuger, L.F.A.G.; Melchers, W.J.G.

    2008-01-01

    Cervical cancer is believed to have a co-factorial etiology in which high-risk human papillomavirus (HPV) infections are considered an essential factor and other elements play an ancillary role. Besides the importance of specific HPV genotypes, other viral cofactors as viral load may influence the

  20. Fat oxidation before and after a high fat load in the obese insulin-resistant state

    NARCIS (Netherlands)

    Blaak, E.E.; Hul, G.; Verdich, C.; Stich, V.; Martinez, A.; Petersen, M.; Feskens, E.J.M.; Patel, K.; Oppert, J.M.; Barbe, P.; Toubro, S.; Anderson, I.; Polak, J.; Astrup, A.; Macdonald, I.A.; Holst, C.; Sørensen, T.I.; Saris, W.H.

    2006-01-01

    Background: Obesity may be associated with a lowered use of fat as a fuel, which may contribute to the enlarged adipose tissue stores. Aim: The aim of the present study was to study fatty acid use in the fasting state and in response to a high fat load in a large cohort of obese subjects (n = 701)

  1. Effect of dissolved oxygen concentration on the bioflocculation process in high loaded MBRs

    NARCIS (Netherlands)

    Faust, L.; Temmink, B.G.; Zwijnenburg, A.; Kemperman, A.J.B.; Rijnaarts, H.

    2014-01-01

    High-loaded membrane bioreactors (HL-MBRs), i.e. MBRs which are operated at extremely short sludge and hydraulic retention times, can be applied to flocculate and concentrate sewage organic matter. The concentrated organics can be used for energy recovery, or for the production of more valuable

  2. Acute Effects of Low-Load/High-Repetition Single-Limb Resistance Training in COPD.

    Science.gov (United States)

    Nyberg, André; Saey, Didier; Martin, Mickaël; Maltais, François

    2016-12-01

    Exercising small muscle groups at a time allows higher muscle specific workloads compared with whole body aerobic exercises in people with chronic obstructive pulmonary disease (COPD). Whether similar effects also occur with partitioning exercise during low load/high-repetition resistance exercises is uncertain.

  3. New impact specimen for adhesives: optimization of high-speed-loaded adhesive joints

    NARCIS (Netherlands)

    Bezemer, A.A.; Guyt, C.B.; Vlot, A.

    1998-01-01

    A new kind of joint specimen has been developed to load the adhesive in pure shear on impact. The specimen is tested with three adhesives at five layer thicknesses, and at three test speeds. From these tests it can be concluded that the rod-ring specimen is suitable for use in impact tests at high s

  4. Note: High resolution ultra fast high-power pulse generator for inductive load using digital signal processor.

    Science.gov (United States)

    Flaxer, Eli

    2014-08-01

    We present a new design of a compact, ultra fast, high resolution and high-powered, pulse generator for inductive load, using power MOSFET, dedicated gate driver and a digital signal controller. This design is an improved circuit of our old version controller. We demonstrate the performance of this pulse generator as a driver for a new generation of high-pressure supersonic pulsed valves.

  5. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Science.gov (United States)

    Janek, Daniela; Zipperer, Alexander; Kulik, Andreas; Krismer, Bernhard; Peschel, Andreas

    2016-08-01

    The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84%) was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  6. Nile red detection of bacterial hydrocarbons and ketones in a high-throughput format.

    Science.gov (United States)

    Pinzon, Neissa M; Aukema, Kelly G; Gralnick, Jeffrey A; Wackett, Lawrence P

    2011-01-01

    A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones.

  7. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Directory of Open Access Journals (Sweden)

    Daniela Janek

    2016-08-01

    Full Text Available The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84% was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  8. High prevalence of multidrug resistance in bacterial uropathogens from Kathmandu, Nepal

    Directory of Open Access Journals (Sweden)

    Baral Pankaj

    2012-01-01

    Full Text Available Abstract Background Urinary Tract Infection (UTI is one of the most common infectious diseases and people of all age-groups and geographical locations are affected. The impact of disease is even worst in low-resource developing countries due to unaware of the UTIs caused by multidrug-resistant (MDR pathogens and the possibility of transfer of MDR traits between them. The present study aimed to determine the prevalence of MDR bacterial isolates from UTI patients, the antibiotic resistance pattern and the conjugational transfer of multidrug resistance phenotypes in Escherichia coli (E. coli. Results Two hundred and nineteen bacterial isolates were recovered from 710 urine samples at Kathmandu Model hospital during the study period. All samples and isolates were investigated by standard laboratory procedures. Among the significant bacterial growth (30.8%, 219 isolates, 41.1% isolates were MDR. The most prevailing organism, E. coli (81.3%, 178 isolates was 38.2% MDR, whereas second most common organism, Citrobacter spp. (5%, 11 isolates was found 72.7% MDR. Extended-spectrum β-lactamase (ESBL production was detected in 55.2% of a subset of MDR E. coli isolates. Among the 29 MDR E. coli isolates, plasmids of size ranging 2-51 kb were obtained with different 15 profiles. The most common plasmid of size 32 kb was detected in all of the plasmid-harbored E. coli strains. The majority of E. coli isolates investigated for the multidrug resistance transfer were able to transfer plasmid-mediated MDR phenotypes along with ESBL pattern with a frequency ranging from 0.3 × 10-7 to 1.5 × 10-7 to an E. coli HB101 recipient strain by conjugation. Most of the donor and recipient strain showed high levels of minimum inhibitory concentration (MIC values for commonly-used antibiotics. Conclusions The high prevalence of multidrug resistance in bacterial uropathogens was observed. Particularly, resistance patterns were alarmingly higher for amoxycillin, co

  9. Preliminary C3 Loading Analysis for Future High-Altitude Unmanned Aircraft in the NAS

    Science.gov (United States)

    Ho, Yan-Shek; Gheorghisor, Izabela; Box, Frank

    2006-01-01

    This document provides a preliminary assessment and summary of the command, control, and communications (C(sup 3)) loading requirements of a generic future high-altitude, long-endurance unmanned aircraft (UA) operating at in the National Airspace System. Two principal types of C(sup 3) traffic are considered in our analysis: communications links providing air traffic services (ATS) to the UA and its human pilot, and the command and control data links enabling the pilot to operate the UA remotely. we have quantified the loading requirements of both types of traffic for two different assumed levels of UA autonomy. Our results indicate that the potential use of UA-borne relays for the ATS links, and the degree of autonomy exercised by the UA during the departure and arrival phases of its flight, will be among the key drivers of C(sup 3) loading and bandwidth requirements.

  10. Numerical analysis of high strain rate failure of electro-magnetically loaded steel sheets

    Directory of Open Access Journals (Sweden)

    Erice Borja

    2015-01-01

    Full Text Available Electro-magnetic forces provide a potentially power full means in designing dynamic experiments with active control of the loading conditions. This article deals with the development of computational models to simulate the thermo-mechanical response of electro-magnetically loaded metallic structures. The model assumes linear electromagnetic constitutive equations and time-independent electric induction to estimate the Joule heating and the Lorentz forces. The latter are then taken into account when evaluating stress equilibrium. A thermo-visco-plastic model with Johnson-Cook type of temperature and strain rate dependence and combined Swift-Voce hardening is used to evaluate the material's thermo-mechanical response. As a first application, the model is used to analyse the effect of electro-magnetic loading on the ductility of advanced high strength steels.

  11. Molecular dynamics simulation of materials response to high strain-rate loading

    Energy Technology Data Exchange (ETDEWEB)

    Belak, J

    1999-07-22

    A molecular dynamics (MD) analysis of conservation of momentum through a shock front is presented. The MD model uses a non-traditional boundary condition that allows simulation in the reference frame of the shock front. Higher order terms proportional to gradients in the density are shown to be non-negligible at the shock front. The simulation is used to study the sequence of thermodynamic states during shock loading. Melting is observed in the simulations, though above the thermodynamic melt curve as is common in homogeneous simulations of melting. High strain-rate tensile loading is applied to the growth of nanoscale voids in copper. Void growth is found to occur by plasticity mechanisms with dislocations emerging from the void surface. [molecular dynamics, shock loading, conservation of momentum, shock melting, void growth

  12. Individual differences at high perceptual load: the relation between trait anxiety and selective attention.

    Science.gov (United States)

    Sadeh, Naomi; Bredemeier, Keith

    2011-06-01

    Attentional control theory (Eysenck et al., 2007) posits that taxing attentional resources impairs performance efficiency in anxious individuals. This theory, however, does not explicitly address if or how the relation between anxiety and attentional control depends upon the perceptual demands of the task at hand. Consequently, the present study examined the relation between trait anxiety and task performance using a perceptual load task (Maylor & Lavie, 1998). Sixty-eight male college students completed a visual search task that indexed processing of irrelevant distractors systematically across four levels of perceptual load. Results indicated that anxiety was related to difficulty suppressing the behavioural effects of irrelevant distractors (i.e., decreased reaction time efficiency) under high, but not low, perceptual loads. In contrast, anxiety was not associated with error rates on the task. These findings are consistent with the prediction that anxiety is associated with impairments in performance efficiency under conditions that tax attentional resources.

  13. The effect of variable stator on performance of a highly loaded tandem axial flow compressor stage

    Science.gov (United States)

    Eshraghi, Hamzeh; Boroomand, Masoud; Tousi, Abolghasem M.; Fallah, Mohammad Toude; Mohammadi, Ali

    2016-06-01

    Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coefficients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils (like CDAs), slotted blades or other boundary layer control methods has helped the designers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade's suction side. Also, in comparison to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.

  14. The Effect of Variable Stator on Performance of a Highly Loaded Tandem Axial Flow Compressor Stage

    Institute of Scientific and Technical Information of China (English)

    Hamzeh Eshraghi; Masoud Boroomand; Abolghasem M.Tousi; Mohammad Toude Fallah; Ali Mohammadi

    2016-01-01

    Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds.Considering the high aerodynamic load effects and structural concerns in the design process,it is possible to obtain higher pressure ratios compared to conventional compressors.However,it must be noted that imposing higher aerodynamic loads results in higher loss coefficients and deteriorates the overall performance.To avoid the loss increase,the boundary layer quality must be studied carefully over the blade suction surface.Employment of advanced shaped airfoils (like CDAs),slotted blades or other boundary layer control methods has helped the designers to use higher aerodynamic loads on compressor blades.Tandem cascade is a passive boundary layer control method,which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads.In fact,the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade's suction side.Also,in comparison to the single blade stators,tandem variable stators have more degrees of freedom,and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance.In the current study,a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage.Following,this design is numerically investigated using a CFD code and the stage characteristic map is reported.Also,the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed.To validate the CFD method,another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.

  15. Development and Application of Mullite Brick With High Refractoriness under Load and Low Creep

    Institute of Scientific and Technical Information of China (English)

    ZHANGSheng; WANGRuikun; 等

    2000-01-01

    This paper introduces of the development and applica-tion of heavily burned mullited brick with high reractoriness under load low creep,which is made of andalusie fine and coarse grains (as aggregate),high alumina bauxite produced in Yangquan county,clay produced in Guangxi provine,industrial alumina powder and silliman-ite powder (as matrix material) and a little amount of ad-ditives and bonded with synthetic bond.

  16. [High-throughput analysis of bacterial community of transition zone in littoral wetland of Wuliangsuhai eutrophic lake].

    Science.gov (United States)

    Li, Jingyu; Du, Ruifang; Zhao, Ji

    2015-05-04

    We studied soil bacterial community composition, abundance and diversity of transition zone along eutrophic lakeside wetland sediments and soils. The total DNA was extracted according to the sediment DNA extraction. Then high-throughput pyrosequencing was used to detect soil bacterial community composition,abundance and diversity based-on 16S rRNA gene. Soil physicochemical properties were tested to analyze its effects on bacterial community according to standard methods. The soil bacterial community composition and relative abundance were very different across transition zone in littoral wetland. Bacteria groups mainly include Proteobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, Planctomycetes and Gemmatimonadetes at phylum level. The diversity index of bacterial communities gradually increased according the land distribution, especially the phylum Proteobacteria and the genus Sulfurimonas. Correlation analysis indicated that the combination of total phosphorus, total water soluble salt and ammonium has the most significant effects on the whole bacterial community structure, and Mantel Test results indicated that the correlation was statistically significant (R = 0.8857, P = 0.037). The bacterial community structure of transition zone is quite different in littoral wetland of Wuliangsuhai eutrophic lake, where Sulfurimonas play potential important roles in biogeochemical cycles of sediments in Wuliangsuhai Lake.

  17. Monitoring bacterial and archaeal community shifts in a mesophilic anaerobic batch reactor treating a high-strength organic wastewater.

    Science.gov (United States)

    Lee, Changsoo; Kim, Jaai; Shin, Seung Gu; Hwang, Seokhwan

    2008-09-01

    Shifts in bacterial and archaeal communities, associated with changes in chemical profiles, were investigated in an anaerobic batch reactor treating dairy-processing wastewater prepared with whey permeate powder. The dynamics of bacterial and archaeal populations were monitored by quantitative real-time PCR and showed good agreement with the process data. A rapid increase in bacterial populations and a high rate of substrate fermentation were observed during the initial period. Growth and regrowth of archaeal populations occurred with biphasic production of methane, corresponding to the diauxic consumption of acetate and propionate. Bacterial community structure was examined by denaturing gel gradient electrophoresis (DGGE) targeting 16S rRNA genes. An Aeromonas-like organism was suggested to be mainly responsible for the rapid fermentation of carbohydrate during the initial period. Several band sequences closely related to the Clostridium species, capable of carbohydrate fermentation, lactate or ethanol fermentation, and/or homoacetogenesis, were also detected. Statistical analyses of the DGGE profiles showed that the bacterial community structure, as well as the process performance, varied with the incubation time. Our results demonstrated that the bacterial community shifted, reflecting the performance changes and, particularly, that a significant community shift corresponded to a considerable process event. This suggested that the diagnosis of an anaerobic digestion process could be possible by monitoring bacterial community shifts.

  18. Presence of a highly efficient binding to bacterial contamination can distort data from binding studies

    Energy Technology Data Exchange (ETDEWEB)

    Balcar, V.J. (Department of Anatomy, University of Sydney, N.S.W. (Australia))

    1990-12-01

    {sup 3}HGABA at low concentrations (5-10 nM) was bound by what appeared to be a GABA receptor binding site in bacterial contamination originating from a batch of distilled water. Under experimental conditions similar to those usually employed in {sup 3}HGABA binding studies, the apparent binding displayed a very high specific component and a high efficiency in terms of {sup 3}HGABA bound per mg of protein. The binding was blocked by muscimol but not by isoguvacine, SR95531 and nipecotic acid. These characteristics suggest that the presence of such spurious binding in the experiments using 3H-labeled ligands in brain homogenates may not always be very obvious and, moreover, it can result in subtle, but serious, distortions of data from such studies, which may not be immediately recognized.

  19. Bacterial production in the water column of small streams highly depends on terrestrial dissolved organic carbon

    Science.gov (United States)

    Graeber, Daniel; Poulsen, Jane R.; Rasmussen, Jes J.; Kronvang, Brian; Zak, Dominik; Kamjunke, Norbert

    2016-04-01

    In the recent years it has become clear that the largest part of the terrestrial dissolved organic carbon (DOC) pool is removed on the way from the land to the ocean. Yet it is still unclear, where in the freshwater systems terrestrial DOC is actually taken up, and for streams DOC uptake was assumed to happen mostly at the stream bottom (benthic zone). However, a recent monitoring study implies that water column but not benthic bacteria are strongly affected by the amount and composition of DOM entering streams from the terrestrial zone. We conducted an experiment to compare the reaction of the bacterial production and heterotrophic uptake in the water column and the benthic zone to a standardized source of terrestrial DOC (leaf leachate from Beech litter). In detail, we sampled gravel and water from eight streams with a gradient in stream size and land use. For each stream four different treatments were incubated at 16°C for three days and each stream: filtered stream water with gravel stones (representing benthic zone bacteria) or unfiltered stream water (representing water column bacteria), both either with (n = 5) or, without (n = 3) leaf leachate. We found that the bacterial uptake of leaf litter DOC was higher for the benthic zone likely due to the higher bacterial production compared to the water column. In contrast, the bacterial production per amount of leaf leachate DOC taken up was significantly higher for the bacteria in the water column than for those in the benthic zone. This clearly indicates a higher growth efficiency with the leaf leachate DOC for the bacteria in the water column than in the benthic zone. We found a high variability for the growth efficiency in the water column, which was best explained by a negative correlation of the DOC demand with stream width (R² = 0.86, linear correlation of log-transformed data). This was not the case for the benthic zone bacteria (R² = 0.02). This implies that water column bacteria in very small streams

  20. Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer

    Directory of Open Access Journals (Sweden)

    Kaul Rajinder

    2009-11-01

    Full Text Available Abstract Background Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia

  1. Durability improvement assessment in different high strength bacterial structural concrete grades against different types of acids

    Indian Academy of Sciences (India)

    Ramin Andalib; M Zaimi Abd Majid; A Keyvanfar; Amirreza Talaiekhozan; Mohd Warid Hussin; A Shafaghat; Rosli Mohd Zin; Chew Tin Lee; Mohammad Ali Fulazzaky; Hasrul Haidar Ismail

    2014-12-01

    This paper provides an insight into a new biotechnological method based on calcite precipitation for achieving high strength bio-concrete durability. It is very clear that mineral precipitation has the potential to enhance construction material resistance towards degradation procedures. The appropriate microbial cell concentration (30 * 105 cells/ml) was introduced onto different structural concrete grades (40, 45 and 50 MPa) by mixing water. In order to study the durability of structural concrete against aggressive agents, specimens were immersed in different types of acids solution (5% H2SO4 and HCl) to compare their effects on 60th, 90th and 120th day. In general, sulphuric acid and hydrochloric acid are known to be the most aggressive natural threats from industrial waters which can penetrate concrete to transfer the soluble calcium salts away from the cement matrix. The experimental results demonstrated that bio-concrete has less weight and strength losses when compared to the ordinary Portland cement concrete without microorganism. It was also found that maximum compressive strength and weight loss occurred during H2SO4 acid immersion as compared to HCl immersion. The density and uniformity of bio-concrete were examined using ultrasonic pulse velocity (UPV) test. Microstructure chemical analysis was also quantified by energy dispersive spectrometer (EDS) to justify the durability improvement in bacterial concrete. It was observed that less sulphur and chloride were noticed in bacterial concrete against H2SO4 and HCl, respectively in comparison to the ordinary Portland cement concrete due to calcite deposition.

  2. Extremely high frequency electromagnetic radiation enforces bacterial effects of inhibitors and antibiotics.

    Science.gov (United States)

    Tadevosyan, Hasmik; Kalantaryan, Vitaly; Trchounian, Armen

    2008-01-01

    The coherent electromagnetic radiation (EMR) of the frequency of 51.8 and 53 GHz with low intensity (the power flux density of 0.06 mW/cm(2)) affected the growth of Escherichia coli K12(lambda) under fermentation conditions: the lowering of the growth specific rate was considerably (approximately 2-fold) increased with exposure duration of 30-60 min; a significant decrease in the number of viable cells was also shown. Moreover, the enforced effects of the N,N'-dicyclohexylcarbodiimide (DCCD), inhibitor of H(+)-transporting F(0)F(1)-ATPase, on energy-dependent H(+) efflux by whole cells and of antibiotics like tetracycline and chloramphenicol on the following bacterial growth and survival were also determined after radiation. In addition, the lowering in DCCD-inhibited ATPase activity of membrane vesicles from exposed cells was defined. The results confirmed the input of membranous changes in bacterial action of low intensity extremely high frequency EMR, when the F(0)F(1)-ATPase is probably playing a key role. The radiation of bacteria might lead to changed metabolic pathways and to antibiotic resistance. It may also give bacteria with a specific role in biosphere.

  3. Isolated Bacterial Spores at High-velocity Survive Surface Impacts in Vacuum

    Science.gov (United States)

    Austin, Daniel; Barney, Brandon

    We present experiments in which bacterial spores were found to survive being accelerated in vacuum to velocities in the range 30-120 m/s and impacted on a dense target. In these experiments, spores of Bacillus subtilis spores were charged using electrospray at atmospheric pressure, dried, and then introduced into high vacuum. Through choice of skimmers and beam tubes, different velocity ranges were achieved. An image-charge detector observed the charged spores, providing total charge and velocity. The spores then impacted a glass target within a collection vessel. After the experiment, the collection vessel contents were extracted and cultured. Several positive and negative controls were used, including the use of antibiotic-resistant spores and antibiotic-containing (rifampicin) agar for culturing. These impact velocities are of particular interest for possible transport of bacterial spores from Mars to Phobos, and may have implications for planetary protection in a Phobos sample return mission. In addition, bacteria may reach similar velocities during a spacecraft crash (e.g., within components, or from spacecraft to surface materials during impact, etc.), raising concerns about forward contamination. The velocities of interest to transport of life between planets (panspermia) are somewhat higher, but these results complement shock-based experiments and contribute to the general discussion of impact survivability of organisms.

  4. Correlation analysis of high-risk human papillomavirus viral load and cervical lesions

    Directory of Open Access Journals (Sweden)

    Xiao-xing MA

    2012-05-01

    Full Text Available Objective  To explore the association between high-risk human papillomavirus (HR-HPV viral load and pathological grades of cervical intraepithelial neoplasia (CIN and cervical cancer. Methods  A total of 1248 patients from General Hospital of PLA, who underwent colposcopy and surgery due to cervical lesions between Jan. 2006 and Aug. 2011 were enrolled in this study, and they were divided five groups: cervicitis, CIN Ⅰ, CIN Ⅱ-Ⅲ, stage Ⅰ cervical cancer and stage Ⅱ cervical cancer. HR-HPV viral load (RLU/CO was determined by the Hybrid Capture Ⅱ (HCⅡ system, and they were categorized into five groups: 0-0.99, 1.00-9.99, 10.00-99.99, 100.00-999.99, ≥1000.00. The mean value and standard deviation of different HR-HPV viral load in the patients with cervicitis or with CIN Ⅰ, CINⅡ-Ⅲ, stage Ⅰ cervical cancer or stage Ⅱ cervical cancer were compared, and the correlation of HR-HPV viral load and pathogenesis of cervical lesions was analyzed. Results  HPV viral loads were significantly higher in CINⅠ(842.1±983.9, CINⅡ-Ⅲ (690.1±795.0, stage Ⅰ cervical cancer (893.1±974.2 and stage Ⅱ cervical cancer (699.5±908.3 patients than in cervicitis patients (274.2±613.6, P < 0.05, and the HPV viral loads in CINⅠ(842.1±983.9 and stage Ⅰ cervical cancer patients were higher than those in CINⅡ-Ⅲ patients (P < 0.05. When HR-HPV viral load was ≥100RLU/CO, the risk of CIN and cervical cancer increased with the increase in viral load, but there was no correlation between the viral load and pathological grades of cervical lesions. In the patients with stage ⅠB-Ⅱ cervical squamous cell carcinoma, when the HR-HPV viral load was ≥100RLU/CO, the risk of lymph node metastasis increased (P < 0.05, and the number of patients with maximum diameter of the cervical tumor ≥4cm also increased (P < 0.05. However, the HR-HPV viral load was not correlated with patient age, pathological type of the lesion, depth of cancer

  5. Quantitative Immobilization of Phthalocyanine onto Bacterial Cellulose for Construction of a High-Performance Catalytic Membrane Reactor.

    Science.gov (United States)

    Chen, Shiliang; Teng, Qiaoling

    2017-07-24

    We report the fabrication of a tetra-amino cobalt (II) phthalocyanine (CoPc)-immobilized bacterial cellulose (BC) functional nanocomposite, CoPc@BC, by quantitative immobilization of CoPc onto a BC membrane. Lab-cultured BC was oxidized by NaIO₄ to generate aldehyde groups on BC for the subsequent CoPc immobilization, the processing conditions were optimized by monitoring both the generated aldehyde content and the resulting CoPc loading. X-ray photoelectron spectroscopy (XPS) was employed to characterize the change of the element bonding environment during the functionalization processes. The CoPc@BC functional nanocomposite was utilized for the treatment of reactive red X-3B dye wastewater. The CoPc molecules in the CoPc@BC nanocomposite can function as an "antenna" to adsorb the target anionic dye molecules, the adsorption takes place both on the surface and in the interior of CoPc@BC. A catalytic membrane reactor (CMR) was assembled with the CoPc@BC nanocomposite, the performance of CMR was evaluated based on the catalytic oxidation behavior of reactive red X-3B, with H₂O₂ as an oxidant. Highly-reactive hydroxyl radical (OH) was involved in the catalytic oxidation process, as detected by electron paramagnetic resonance (EPR). Under optimal operating conditions of a flow rate of 6 mL/min, a reaction temperature of 50 °C, and an H₂O₂ concentration of 10 mmol/L, the decoloration rate of CMR was as high as 50 μmol⋅min(-1)⋅g(-1).

  6. Highly loaded Ni-based catalysts for low temperature ethanol steam reforming

    Science.gov (United States)

    Wang, Tuo; Ma, Hongyan; Zeng, Liang; Li, Di; Tian, Hao; Xiao, Shengning; Gong, Jinlong

    2016-05-01

    This paper describes the design of high-loading Ni/Al2O3 catalysts (78 wt% Ni) for low temperature ethanol steam reforming. The catalysts were synthesized via both co-precipitation (COP) and impregnation (IMP) methods. All the catalysts were measured by N2 adsorption-desorption, XRD, H2-TPR, and H2 pulse chemisorption. The characterization results demonstrated that the preparation method and the loading significantly affected the nickel particle size, active nickel surface area and catalytic performance. Over COP catalysts, large nickel particles were presented in nickel aluminum mixed oxides. In comparison, IMP catalysts gained more ``free'' NiO particles with weak interaction with the aluminum oxide. Consequently, COP catalysts yielded smaller nickel particles and larger active nickel surface areas than those of IMP catalysts. High loading is beneficial for obtaining sufficient active nickel sites when nickel particles are dispersed via COP, whereas excessive nickel content is not desired for catalysts prepared by IMP. Specifically, the 78 wt% nickel loaded catalyst synthesized by COP possessed small nickel particles (~6.0 nm) and an abundant active nickel area (35.1 m2 gcat-1). Consequently, COP-78 achieved superior stability with 92% ethanol conversion and ~35% H2 selectivity at 673 K for 30 h despite the presence of a considerable amount of coke.

  7. Prediction of Stress Concentration effect under Thermal and Dynamic loads on a High Pressure Turbine Rotor

    Directory of Open Access Journals (Sweden)

    R.Nagendra Babu

    2010-08-01

    Full Text Available Geometric discontinuities cause a large variation of stress and produce a significant increase in stress. The high stress due to the variation of geometry is called as ‘stress concentration’. This will increase when the loads are further applied. There are many investigators who have studied the stress distribution around the notches, grooves, and other irregularities of various machine components. This paper analyses the effects of thermal and fatigue load on a steam turbine rotor under the operating conditions. Stresses due to thermal and dynamic loads of High Pressure Steam Turbine Rotor of 210MW power station are found in two stages. A source code is developed for calculating the nominal stress at each section of HPT rotor. Maximum stress is obtained using FEA at the corresponding section. Thermal and Fatigue Stress Concentration Factors at each section are calculated. It is observed that the SCFdue to the combined effect of thermal and dynamic loads at the temperatures beyond 5400C is exceeding the safe limits.

  8. High efficiency WCDMA power amplifier with Pulsed Load Modulation (PLM) technique

    Science.gov (United States)

    Liao, Shu-Hsien

    In wireless communication, high data rate complex modulation is used for spectral efficiency. However, power efficiency of power amplifier degrades when complex modulation is applied. Therefore, efficiency enhancement is necessary to maintain the performance. However, conventional efficiency enhancement schemes are nonlinear and performance improvement can only be optimized over a small range of power level. In order to preserve linearity and power efficiency, we propose a new digital power amplification technique "Pulsed Load Modulation (PLM)" for high efficiency and linear amplification. The PLM technique realizes load impedance modulation in digital fashion which is insensitive to device nonlinearity. Furthermore, the optimum power efficiency can be maintained over a wide range of output power. In this work, a PLM power amplifier module has been fabricated and to demonstrate the ability of PLM to provide high efficiency and linear amplification.

  9. Progress on High Power Tests of Dielectric-Loaded Accelerating Structures

    CERN Document Server

    Jing, Chunguang; Gold, Steven H; Kinkead, Allen; Konecny, Richard; Power, John G

    2005-01-01

    This paper presents a progress report on a series of high-power rf experiments that were carried out to evaluate the potential of the Dielectric-Loaded Accelerating (DLA) structure for high-gradient accelerator operation. Since the last PAC meeting in 2003, we have tested DLA structures loaded with two different ceramic materials: Alumina (Al2O3) and MCT (MgxCa1-xTiO3). The alumina-based DLA experiments have concentrated on the effects of multipactor in the structures under high-power operation, and its suppression using TiN coatings, while the MCT experiments have investigated the dielectric joint breakdown observed in the structures due to local field enhancement. In both cases, physical models have been set up, and the potential engineering solutions are being investigated.

  10. Eficacia de cinco desinfectantes para la reducción bacteriana doméstica Efficacy of five disinfectants to reduce bacterial load in the household

    Directory of Open Access Journals (Sweden)

    Julián Stambullian

    2011-06-01

    count in kitchen of 66.0 CFU/cm², and in bathroom 40.1 CFU/cm². Samples taken immediately after-cleaning (no group discrimination contained: kitchen 0.8 CFU/cm²; bathroom < 1 CFU/ cm². After one week (intervention group vs. control group contained: kitchen 18.0 vs. 32.5 CFU/cm²; bathroom 12.7 vs. 7.7 CFU/cm². After one month (intervention group vs. control group: kitchen 60.1 vs. 62.1 CFU/cm²; bathroom 37.0 vs. 42.0 CFU/cm². A remarkable dicrease of bacterial load was observed in both groups, which suggests that not only product quality but also education for suitable use plays a key role in successful house disinfection. This approach could be an important tool for improving prevention of foodborne infections since fecal coliforms widely predominated in all analyzed samples.

  11. An analysis in vivo of intracanal bacterial load before and after chemo-mechanical preparation: A comparative analysis of two irrigants and two activation techniques

    Science.gov (United States)

    Rico-Romano, Cristina; Zubizarreta-Macho, Álvaro; Baquero-Artigao, María-Rosario

    2016-01-01

    Background The goals of this randomized double-blind trial were to assess the antimicrobial activity in vivo of Sodium hypochlorite (NaOCl) vs. chlorhexidine gluconate (CHX) used in combination either with EndoActivator® or IRRI S® files in patients with apical periodontitis. Material and Methods A total of 120 patients with apical periodontitis (in single or multiple root canals) were randomly assigned to the four irrigation protocols outlined below: Group A: 5.25% sodium hypochlorite (NaOCl) + EndoActivator®; Group B: 5.25% NaOCl + IRRI S® files; Group C: 2% chlorhexidine gluconate (CHX) + EndoActivator®; Group D: 2% CHX + IRRI S® files. Paper points were used to collect microbiological samples before (1A samples) and after (1B samples) irrigation. Viable colony-forming units (CFU) were quantified twice: (1) without speciation, and (2) only for Enterococcus Faecalis(EF). Statistical analysis was performed using SPSS 22.0 for Windows. Results No significant differences were observed between NaOCl and CHX in the reduction of CFU; in fact, reduction was irrigants. Conversely, statistically significant differences were found between the two activation techniques (sonic and ultrasonic) in the reduction of Enterococcus Faecalis(EF). Thus, the effectiveness of ultrasonic activation was significantly higher (irrigants with the two activation techniques (groups A, B, C and D), significant differences were observed between group A and B (p=0.025) in the reduction of EF populations, reaching up to 94%. Conclusions NaClO and CHX are effective in reducing intracanal bacterial load. Ultrasonic activation is the most effective activation technique in reducing EF populations. Key words:Chlorhexidine gluconate, sodium hypochlorite, ultrasonic irrigation, sonic irrigation, apical periodontitis, Enterococcus faecalis. PMID:26855714

  12. Self-healing of mechanically-loaded self consolidating concretes with high volumes of fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Mustafa Sahmaran; Suleyman B. Keskin; Gozde Ozerkan; Ismail O. Yaman [University of Gaziantep, Gaziantep (Turkey). Department of Civil Engineering

    2008-11-15

    This article discusses the effects of self-healing on self consolidating concretes incorporating high volumes of fly ash (HVFA-SCC) when subjected to continuous water exposure. For this purpose, self consolidating concretes with fly ash replacement ratios of 0%, 35%, and 55% were prepared having a constant water-cementitious material ratio of 0.35. A uniaxial compression load was applied to generate microcracks in concrete where cylindrical specimens were pre-loaded up to 70% and 90% of the ultimate compressive load determined at 28 days. Later, the extent of damage was determined as percentage of loss in mechanical properties and percentage of increase in permeation properties. After pre-loading, concrete specimens were stored in water for a month and the mechanical and permeation properties are monitored at every two weeks. It was observed that HVFA-SCC mixtures initially lost 27% of their strength when pre-loaded up to 90% of their ultimate strength, and after 30 days of water curing that reduction was only 7%, indicating a substantial healing. On the other hand, for SCC specimens without fly ash that were pre-loaded to the same level, the loss in strength was initially 19%, and after a month of moist curing it was only 13%. Similar observations were also made on the permeation properties with greater effects. As the HVFA-SCCs studied have an important amount of unhydrated fly ash available in their microstructure, these observations are attributed to the self-healing of the pre-existing cracks, mainly by hydration of anhydrous fly ash particles on the crack surfaces.

  13. Mechanical model for yield strength of nanocrystalline materials under high strain rate loading

    Institute of Scientific and Technical Information of China (English)

    朱荣涛; 周剑秋; 马璐; 张振忠

    2008-01-01

    To understand the high strain rate deformation mechanism and determine the grain size,strain rate and porosity dependent yield strength of nanocrystalline materials,a new mechanical model based on the deformation mechanism of nanocrystalline materials under high strain rate loading was developed.As a first step of the research,the yield behavior of the nanocrystalline materials under high strain rate loading was mainly concerned in the model and uniform deformation was assumed for simplification.Nanocrystalline materials were treated as composites consisting of grain interior phase and grain boundary phase,and grain interior and grain boundary deformation mechanisms under high strain rate loading were analyzed,then Voigt model was applied to coupling grain boundary constitutive relation with mechanical model for grain interior phase to describe the overall yield mechanical behavior of nanocrystalline materials.The predictions by the developed model on the yield strength of nanocrysatlline materials at high strain rates show good agreements with various experimental data.Further discussion was presented for calculation results and relative experimental observations.

  14. Direct FEM-computation of load carrying capacity of highly loaded passive components; Direkte FEM - Berechnung der Tragfaehigkeit hochbeanspruchter passiver Komponenten

    Energy Technology Data Exchange (ETDEWEB)

    Staat, M.; Heitzer, M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Sicherheitsforschung und Reaktortechnik

    1998-11-01

    Detailed, inelastic FEM analyses yield accurate information about the stresses and deformations in passive components. The local loading conditions, however, cannot be directly compared with a limit load in terms of structural mechanics. Concentration on the load carrying capacity is an approach simplifying the analysis. Based on the plasticity theory, limit and shakedown analyses calculate the load carrying capacities directly and exactly. The paper explains the implementation of the limit and shakedown data sets in a general FEM program and the direct calculation of the load carrying capacities of passive components. The concepts used are explained with respect to common structural analysis. Examples assuming high local stresses illustrate the application of FEM-based limit and shakedown analyses. The calculated interaction diagrams present a good insight into the applicable operational loads of individual passive components. The load carrying analysis also opens up a structure mechanics-based approach to assessing the load-to-collapse of cracked components made of highly ductile fracture-resistant material. (orig./CB) [Deutsch] Genaue Kenntnis der Spannungen und Verformungen in passiven Komponenten gewinnt man mit detailierten inelastischen FEM Analysen. Die lokale Beanspruchung laesst sich aber nicht direkt mit einer Beanspruchbarkeit im strukturmechanischen Sinne vergleichen. Konzentriert man sich auf die Frage nach der Tragfaehigkeit, dann vereinfacht sich die Analyse. Im Rahmen der Plastizitaetstheorie berechnen Traglast- und Einspielanalyse die tragbaren Lasten direkt und exakt. In diesem Beitrag wird eine Implementierung der Traglast- und Einspielsaetze in ein allgemeines FEM Programm vorgestellt, mit der die Tragfaehigkeit passiver Komponenten direkt berechnet wird. Die benutzten Konzepte werden in Bezug auf die uebliche Strukturanalyse erlaeutert. Beispiele mit lokal hoher Beanspruchung verdeutlichen die Anwendung der FEM basierten Traglast- und

  15. Flow separation control by using bowed blade in highly loaded turbine cascades

    Institute of Scientific and Technical Information of China (English)

    YAMAMOTO; Atsumasa

    2009-01-01

    Due to the serious flow separations and centralized vortices,there are high secondary losses in highly loaded turbines.It is imperative to find measures to control the flow separation and vortices hence improve the turbine performance.This paper reports our recent progress on flow separation and vor-tices control in highly loaded turbine cascades by using bowed blades.Two sets of highly loaded tur-bine cascades with the turning angles of 113° and 160°,and each with 7 bowed blade angles 0°(straight),±10°,±20° and ±30° were experimentally investigated.Both internal flow field measurement and flow visualization on the blade surfaces were conducted,and the effects of blade bowing on the flow topology,distribution of vorticity and the flow energy loss were discussed.The results show that,for the cascade with the turning angle of 113°,the appropriately positive bow angle could reduce the flow energy loss;whereas for the cascade with the turning angle of 160°,the well selected negative bow angle can give the better aerodynamic performance.

  16. Flow separation control by using bowed blade in highly loaded turbine cascades

    Institute of Scientific and Technical Information of China (English)

    TAN ChunQing; ZHANG HuaLiang; CHEN HaiSheng; DONG XueZhi; ZHAO HongLei; YAMAMOTO Atsumasa

    2009-01-01

    Due to the serious flow separations and centralized vortices, there are high secondary losses in highly loaded turbines. It is imperative to find measures to control the flow separation and vortices hence improve the turbine performance. This paper reports our recent progress on flow separation and vor-tices control in highly loaded turbine cascades by using bowed blades. Two sets of highly loaded tur-bine cascades with the turning angles of 113°and 160°, and each with 7 bowed blade angles 0°(straight),±10°, ±20° and ±30° were experimentally investigated. Both internal flow field measurement and flow visualization on the blade surfaces were conducted, and the effects of blade bowing on the flow topology, distribution of vorticity and the flow energy loss were discussed. The results show that, for the cascade with the turning angle of 113°, the appropriately positive bow angle could reduce the flow energy loss; whereas for the cascade with the turning angle of 160°, the well selected negative bow angle can give the better aerodynamic performance.

  17. Preparation of high molecular weight gDNA and bacterial artificial chromosome (BAC) libraries in plants.

    Science.gov (United States)

    Biradar, Siddanagouda S; Nie, Xiaojun; Feng, Kewei; Weining, Song

    2014-01-01

    Bacterial artificial chromosome (BAC) libraries are extremely valuable large-insert DNA libraries for physical mapping, positional cloning, comparative genomic analysis, complete genome sequencing, and evolutionary studies. Due to their stability and relative simplicity BAC libraries are most preferred over other approaches for cloning large genomic DNA fragments for large-insert libraries. Isolation of intact high molecular weight (HMW) DNA is a critical step underlying the success of large-insert genomic DNA library construction. It requires the isolation of purified nuclei, embedding them into LMP agarose plugs, restriction digestion of the plugs, and quite often size selection using PFGE and electro-elution of insert DNA. The construction of BAC libraries is complex and challenging for most molecular laboratories. To facilitate the construction of BAC libraries, we present a step-by-step protocol for isolation of HMW DNA and construction of plant BAC libraries.

  18. Optimized cultivation of highly-efficient degradation bacterial strains and their degradation ability towards pyrene

    Institute of Scientific and Technical Information of China (English)

    HOU Shuyu; ZHANG Qingmin; DUO Miao; ZHANG Yang; SUN Hongwen

    2007-01-01

    Two bacterial strains,Pyl and Py4,have been tamed and isolated through long cultivation with polycyclic aromatic hydrocarbon-pyrene as the single carbon source.It has been proven that they are both highly-efficient pyrene degrading bacteria and both Bacillus sp..The pyrene degradation ability of separated Pyl,Py4 and the consortium of equal Pyl and Py4 was studied in this project.It is shown that pyrene degradation rates were 88% in 10hr by Py1,84% in 14hr by Py4,and 88% in 8hr by the consortium.It was also determined that the best degradation temperatures were 37℃ and pH 7.0 respectively.The influence of different nutrient substrates added in the degradation experiments was also studied.It was shown that sodium salicylate,sodium acetate and yeast exuact had obvious simulative effect,but glucose had no obvious effect.

  19. Formation and post-formation dynamics of bacterial biofilm streamers as highly viscous liquid jets

    CERN Document Server

    Das, Siddhartha

    2013-01-01

    It has been recently reported that in presence of low Reynolds number (Re<<1) transport, preformed bacterial biofilms, several hours after their formation, may degenerate in form of filamentous structures, known as streamers. In this letter, we explain that such streamers form as the highly viscous liquid states of the intrinsically viscoelastic biofilms. Such "viscous liquid" state can be hypothesized by noting that the time of appearance of the streamers is substantially larger than the viscoelastic relaxation time scale of the biofilms, and this appearance is explained by the inability of a viscous liquid to withstand an external shear. Further, by identifying the post formation dynamics of the streamers as that of a viscous liquid jet in a surrounding flow field, we can interpret several unexplained issues associated with the post-formation dynamics of streamers, such as the clogging of the flow passage or the exponential time growth of streamer dimensions.

  20. Over-starvation aggravates intestinal injury and promotes bacterial and endotoxin translocation under high-altitude hypoxic environment

    Institute of Scientific and Technical Information of China (English)

    Qi-Quan Zhou; Ding-Zhou Yang; Yong-Jun Luo; Su-Zhi Li; Fu-Yu Liu; Guan-Song Wang

    2011-01-01

    AIM: To study whether over-starvation aggravates intestinal mucosal injury and promotes bacterial and endotoxin translocation in a high-altitude hypoxic environment. METHODS: Sprague-Dawley rats were exposed to hypobaric hypoxia at a simulated altitude of 7000 m for 72 h. Lanthanum nitrate was used as a tracer to detect intestinal injury. Epithelial apoptosis was observed with terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Serum levels of diamino oxidase (DAO), malondialdehyde (MDA), glutamine (Gln), superoxide dismutase (SOD) and endotoxin were measured in intestinal mucosa. Bacterial translocation was detected in blood culture and intestinal homogenates. In addition, rats were given Gln intragastrically to observe its protective effect on intestinal injury. RESULTS: Apoptotic epithelial cells, exfoliated villi and inflammatory cells in intestine were increased with edema in the lamina propria accompanying effusion of red blood cells. Lanthanum particles were found in the intercellular space and intracellular compartment. Bacterial translocation to mesenteric lymph nodes (MLN) and spleen was evident. The serum endotoxin, DAO and MDA levels were significantly higher while the serum SOD, DAO and Gln levels were lower in intestine (P < 0.05). The bacterial translocation number was lower in the high altitude hypoxic group than in the high altitude starvation group (0.47 ± 0.83 vs 2.38 ± 1.45, P < 0.05). The bacterial translocation was found in each organ, especially in MLN and spleen but not in peripheral blood. The bacterial and endotoxin translocations were both markedly improved in rats after treatment with Gln. CONCLUSION: High-altitude hypoxia and starvation cause severe intestinal mucosal injury and increase bacterial and endotoxin translocation, which can be treated with Gln.

  1. Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men.

    Directory of Open Access Journals (Sweden)

    Nicholas A Burd

    Full Text Available BACKGROUND: We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. METHODOLOGY/PRINCIPAL FINDINGS: Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2 performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM until volitional failure (90FAIL, 30% 1RM work-matched to 90%FAIL (30WM, or 30% 1RM performed until volitional failure (30FAIL. Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX, myofibrillar (MYO, and sarcoplasmic (SARC protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121% and MYO (87% protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199% above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023 and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025. Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05 only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237% and 30FAIL (312% conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02 regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. CONCLUSIONS/SIGNIFICANCE: These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.

  2. Aerodynamic loading distribution effects on the overall performance of ultra-high-lift LP turbine cascades

    Science.gov (United States)

    Berrino, M.; Satta, F.; Simoni, D.; Ubaldi, M.; Zunino, P.; Bertini, F.

    2014-02-01

    The present paper reports the results of an experimental investigation aimed at comparing aerodynamic performance of three low-pressure turbine cascades for several Reynolds numbers under steady and unsteady inflows. This study is focused on finding design criteria useful to reduce both profile and secondary losses in the aero-engine LP turbine for the different flight conditions. The baseline blade cascade, characterized by a standard aerodynamic loading (Zw=1.03), has been compared with two Ultra-High-Lift profiles with the same Zweifel number (Zw=1.3 for both cascades), but different velocity peak positions, leading to front and mid-loaded blade cascade configurations. The aerodynamic flow fields downstream of the cascades have been experimentally investigated for Reynolds numbers in the range 70000plane downstream of the cascade for both inflow conditions. The analysis of the results allows the evaluation of the aerodynamic performance of the blade cascades in terms of profile and secondary losses and the understanding of the effects of loading distribution and Zweifel number on secondary flows. When operating under unsteady inflow, contrarily to the steady case, the mid-loaded cascade has been found to be characterized by the lowest profile and secondary losses, making it the most attractive solution for the design of blades working in real conditions where unsteady inflow effects are present.

  3. Crystallization Kinetics of Indomethacin/Polyethylene Glycol Dispersions Containing High Drug Loadings.

    Science.gov (United States)

    Duong, Tu Van; Van Humbeeck, Jan; Van den Mooter, Guy

    2015-07-06

    The reproducibility and consistency of physicochemical properties and pharmaceutical performance are major concerns during preparation of solid dispersions. The crystallization kinetics of drug/polyethylene glycol solid dispersions, an important factor that is governed by the properties of both drug and polymer has not been adequately explored, especially in systems containing high drug loadings. In this paper, by using standard and modulated differential scanning calorimetry and X-ray powder diffraction, we describe the influence of drug loading on crystallization behavior of dispersions made up of indomethacin and polyethylene glycol 6000. Higher drug loading increases the amorphicity of the polymer and inhibits the crystallization of PEG. At 52% drug loading, polyethylene glycol was completely transformed to the amorphous state. To the best of our knowledge, this is the first detailed investigation of the solubilization effect of a low molecular weight drug on a semicrystalline polymer in their dispersions. In mixtures containing up to 55% indomethacin, the dispersions exhibited distinct glass transition events resulting from amorphous-amorphous phase separation which generates polymer-rich and drug-rich domains upon the solidification of supercooled polyethylene glycol, whereas samples containing at least 60% drug showed a single amorphous phase during the period in which crystallization normally occurs. The current study demonstrates a wide range in physicochemical properties of drug/polyethylene glycol solid dispersions as a result of the complex nature in crystallization of this system, which should be taken into account during preparation and storage.

  4. Enzymatic hydrolysis of pelletized AFEX™-treated corn stover at high solid loadings.

    Science.gov (United States)

    Bals, Bryan D; Gunawan, Christa; Moore, Janette; Teymouri, Farzaneh; Dale, Bruce E

    2014-02-01

    Ammonia fiber expansion (AFEX™) pretreatment can be performed at small depots, and the pretreated biomass can then be pelletized and shipped to a centralized refinery. To determine the feasibility of this approach, pelletized AFEX-treated corn stover was hydrolyzed at high (18-36%) solid loadings. Water absorption and retention by the pellets was low compared to unpelletized stover, which allowed enzymatic hydrolysis slurries to remain well mixed without the need for fed-batch addition. Glucose yields of 68% and xylose yields of 65% were obtained with 20 mg enzyme/g glucan and 18% solid loading after 72 h, compared to 61% and 59% for unpelletized corn stover. Pelletization also slightly increased the initial rate of hydrolysis compared to unpelletized biomass. The ease of mixing and high yields obtained suggests that pelletization after AFEX pretreatment could have additional advantages beyond improved logistical handling of biomass.

  5. EFFECTS OF HIGH-IMPACT MECHANICAL LOADING ON SYNOVIAL CELL CULTURES

    Directory of Open Access Journals (Sweden)

    Hui Bin Sun

    2004-03-01

    Full Text Available Cartilage metabolism in response to mechanical loading is an important subject in sports science and medicine. In animal studies high-impact exercise is known to stimulate bone adaptation and increase bone mass. However, mechanical impacts potentially induce tissue swelling and occasionally degradation of connective tissues in synovium and articular cartilage. These detrimental outcomes should be properly evaluated clinically and biochemically. Using two synovial cell cultures derived from normal and rheumatic tissues, we examined the biochemical effects of impulsive mechanical loads on expression and activities of influential proteolytic enzymes in joints, matrix metalloproteinases (MMPs, and their natural inhibitors, tissue inhibitors of metalloproteinases (TIMPs. The molecular analysis demonstrates that an impact factor (Im, the ratio of the maximum force to weight, served as a good indicator for assessment of the inflammatory responses. The results showed that high impact above Im = 40 to 80 elevated not only expression but also enzymatic activities of MMPs

  6. Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

    Energy Technology Data Exchange (ETDEWEB)

    Freemire, Ben [IIT, Chicago; Bowring, Daniel [Fermilab; Kochemirovskiy, Alexey [Chicago U.; Moretti, Alfred [Fermilab; Peterson, David [Fermilab; Tollestrup, Alvin [Fermilab; Torun, Yagmur [IIT, Chicago; Yonehara, Katsuya [Fermilab

    2016-06-01

    Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% alumina ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.

  7. Molecular dynamics simulation of functionalized graphene surface for high efficient loading of doxorubicin

    Science.gov (United States)

    Mirhosseini, Mohammad Masoud; Rahmati, Mahmoud; Zargarian, Seyed Shahrooz; Khordad, Reza

    2017-08-01

    Molecular dynamics simulations are performed to study the design and optimization of nanocarriers with high drug loading capacity. Functionalized graphene is considered as the nominated high capacity drug carrier and Dox as the drug model. The graphene surface functionalized with hydroxyl (- OH), carboxyl (- COOH), methyl (- CH3) and amine (- NH2) groups and their associated properties are investigated. The simulation results are illustrated that G - COOH surface absorbs Dox more effectively in comparison to other functionalized graphene surfaces due to the higher binding energy of carboxylic groups and the model drug. The effect of hydrogen bonding, temperature and surface porosity are also evaluated. The results show that binding energy and the solubility parameter are temperature-dependent. The simulation results in this present work reveal the underlying mechanisms of Dox loading on neat and functionalized graphene surfaces may be employed to design better graphene-based nanocarriers for the Dox delivery applications.

  8. Investigation of Internal Flow in Ultra—Highly Loaded Turbine Cascade by PIV Method

    Institute of Scientific and Technical Information of China (English)

    A.Senoo; S.MizukiandH.Tsujita; 等

    2000-01-01

    The highly loaded turbine blades are able to reduce both the number of blades and the stages of turbojet-engines.In this study,PIV(Particle Image Velocimetry)method is used for the measuremts of the secondary flow in ultra-highly loaded tubine blade casecades.The results obtained by the PIV method clearly show the complicated behavior of the secondary flow in the cascade.The horseshoe vortex and the passage vortex are observed inside the cascade,Moreover.the wake generated by the accumulation of the low energy fluid by the passage vortex near the suction side and that discharged toward downstream of the trailing edge has been recognized.

  9. Batch medication of intestinal infections in nursery pigs—A randomised clinical trial on the efficacy of treatment strategy, type of antibiotic and bacterial load on average daily weight gain

    DEFF Research Database (Denmark)

    Weber, Nicolai Rosager; Pedersen, Ken Steen; Hansen, Christian Fink

    2017-01-01

    after weaning) on average daily weight gain (ADG); (2) to compare the effect of treatment with doxycycline or tylosine on diarrhoea prevalence, pathogenic bacterial load, and ADG; (3) to evaluate PCR testing of faecal pen floor samples as a diagnostic tool for determining the optimal time of treatment...... LI-positive pens (p = 0.004), lower excretion levels of LI (p = 0.013), and fewer pens with a high level of LI (p = 0.031) compared to pens treated with tylosine. There was no significant difference in F4, F18 and PILO levels after treatment with the two antibiotic compounds. There was a significant...... difference (p = 0.04) of mean diarrhoea prevalence on day 21 of the study between pens treated with tylosine (0.254, 95% CI: 0.184–0.324), and doxycycline (0.167, 95% CI: 0.124–0.210). The type of antibiotic compound was not found to have a significant effect on ADG (p = 0.209). (3) Pigs starting treatment...

  10. The role of volume-load in strength and absolute endurance adaptations in adolescent's performing high- or low-load resistance training.

    Science.gov (United States)

    Steele, James; Fisher, James P; Assunção, Ari R; Bottaro, Martim; Gentil, Paulo

    2017-02-01

    This study compared high- (HL) and low-load (LL) resistance training (RT) on strength, absolute endurance, volume-load, and their relationships in untrained adolescents. Thirty-three untrained adolescents of both sexes (males, n = 17; females, n = 16; 14 ± 1 years) were randomly assigned into either (i) HL (n = 17): performing 3 sets of 4-6 repetitions to momentary concentric failure; or (ii) LL (n = 16): performing 2 sets of 12-15 repetitions to momentary concentric failure. RT was performed for 2×/week for 9 weeks. Change in maximum strength (1 repetition maximum) and absolute muscular endurance for barbell bench press was assessed. Weekly volume-load was calculated as sets (n) × repetitions (n) × load (kg). Ninety-five percent confidence intervals (CIs) revealed that both groups significantly increased in strength and absolute endurance with large effect sizes (d = 1.51-1.66). There were no between-group differences for change in strength or absolute endurance. Ninety-five percent CIs revealed that both groups significantly increased in weekly volume-load with large effect sizes (HL = 1.66, LL = 1.02). There were no between-group differences for change in volume-load though average weekly volume-load was significantly greater for LL (p strength (r = 0.650, p = 0.005) and absolute endurance (r = 0.552, p = 0.022) increases. Strength and absolute endurance increases do not differ between HL and LL conditions in adolescents when performed to momentary concentric failure. Under HL conditions greater weekly volume-load is associated with greater strength and absolute endurance increases.

  11. The effect of high-frequencies loading on the fatigue cracking of nodular cast iron

    Directory of Open Access Journals (Sweden)

    R. Ulewicz

    2017-01-01

    Full Text Available The article presents the results of fatigue tests using high-frequency loading of nodular cast iron. Nodular cast iron GJS-500-7, GJS-600-3 and cast iron ADI with a tensile strength of Rm = 1 125 MPa were used for the tests. The fatigue tests were conducted on a resonance testing machine. For the cast iron grades under investigation, fatigue characteristics in high and ultra-high-cycle regions were experimentally determined. After the completion of the tests, the fractographic analysis of fatigue fractures was made with the aim of determining the fatigue crack initiation location and the fracture mechanism.

  12. Chilled ceiling and displacement ventilation system: Laboratory study with high cooling load

    OpenAIRE

    Schiavon, S.; Bauman, FS; Tully, B; Rimmer, J

    2015-01-01

    © 2015 ASHRAE.Radiant chilled ceilings with displacement ventilation represent a promising system that combines the energy efficiency of both subsystems with the opportunity for improved ventilation performance. Laboratory experiments were conducted for an interior zone office with a very high cooling load (91.0 W/m2) and with two different heat source heights to investigate their influence on thermal stratification and air change effectiveness. The results showed that displacement ventilatio...

  13. Local Release of Highly Loaded Antibodies from Functionalized Nanoporous Support for Cancer Immunotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Chenghong; Liu, P.; Chen, Baowei; Mao, Yumeng; Engelmann, Heather E.; Shin, Yongsoon; Jaffar, Jade; Hellstrom, Ingegerd; Liu, Jun; Hellstrom, Karl E.

    2010-05-26

    We report that antibodies can be loaded in functionalized mesoporous silica (FMS) with super-high density to provide long-lasting local release at a given site. Preliminary data indicate that FMS-antibody injected directly into a mouse melanoma induces a greater inhibition of tumor growth than seen in various controls, including the antibody injected intraperitoneally. Our findings introduce a novel approach for local delivery of therapeutically active proteins to tumors and potentially, other diseases.

  14. Advanced thermoplastic composites: An attractive new material for usage in highly loaded vehicle components

    Energy Technology Data Exchange (ETDEWEB)

    Mehn, R.; Seidl, F.; Peis, R.; Heinzmann, D.; Frei, P. [BMW AG Muenchen (Germany)

    1995-10-01

    Beside the lightweight potential and further well known advantages of advanced composite materials, continuous fiber reinforced thermoplastics employed in vehicle structural parts especially offer short manufacturing cycle times and an additional economically viable manufacturing process. Presenting a frame structure concept for two highly loaded vehicle parts, a safety seat and a side door, numerous features concerning the choice of suitable composite materials, design aspects, investigations to develop a thermoforming technique, mature for a series production of vehicle parts, are discussed.

  15. Microbial activities in a vertical-flow wetland system treating sewage sludge with high organic loads

    Energy Technology Data Exchange (ETDEWEB)

    Wang, R. Y.; Perissol, C.; Baldy, V.; Bonin, G.; Korboulewsky, N.

    2009-07-01

    The rhizosphere is the most active zone in treatment wetlands where take place physicochemical and biological processes between the substrate, plants, microorganisms, and contaminants. Microorganisms play the key role in the mineralisation of organic matter. substrate respiration and phosphatase activities (acid and alkaline) were chosen as indicators of microbial activities, and studied in a vertical-flow wetland system receiving sewage sludge with high organic loads under the Mediterranean climate. (Author)

  16. Theoretical research and experimental validation of elastic dynamic load spectra on bogie frame of high-speed train

    Science.gov (United States)

    Zhu, Ning; Sun, Shouguang; Li, Qiang; Zou, Hua

    2016-05-01

    When a train runs at high speeds, the external exciting frequencies approach the natural frequencies of bogie critical components, thereby inducing strong elastic vibrations. The present international reliability test evaluation standard and design criteria of bogie frames are all based on the quasi-static deformation hypothesis. Structural fatigue damage generated by structural elastic vibrations has not yet been included. In this paper, theoretical research and experimental validation are done on elastic dynamic load spectra on bogie frame of high-speed train. The construction of the load series that correspond to elastic dynamic deformation modes is studied. The simplified form of the load series is obtained. A theory of simplified dynamic load-time histories is then deduced. Measured data from the Beijing-Shanghai Dedicated Passenger Line are introduced to derive the simplified dynamic load-time histories. The simplified dynamic discrete load spectra of bogie frame are established. Based on the damage consistency criterion and a genetic algorithm, damage consistency calibration of the simplified dynamic load spectra is finally performed. The computed result proves that the simplified load series is reasonable. The calibrated damage that corresponds to the elastic dynamic discrete load spectra can cover the actual damage at the operating conditions. The calibrated damage satisfies the safety requirement of damage consistency criterion for bogie frame. This research is helpful for investigating the standardized load spectra of bogie frame of high-speed train.

  17. Highly heterogeneous soil bacterial communities around Terra Nova Bay of Northern Victoria Land, Antarctica.

    Directory of Open Access Journals (Sweden)

    Mincheol Kim

    Full Text Available Given the diminished role of biotic interactions in soils of continental Antarctica, abiotic factors are believed to play a dominant role in structuring of microbial communities. However, many ice-free regions remain unexplored, and it is unclear which environmental gradients are primarily responsible for the variations among bacterial communities. In this study, we investigated the soil bacterial community around Terra Nova Bay of Victoria Land by pyrosequencing and determined which environmental variables govern the bacterial community structure at the local scale. Six bacterial phyla, Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, Cyanobacteria, and Bacteroidetes, were dominant, but their relative abundance varied greatly across locations. Bacterial community structures were affected little by spatial distance, but structured more strongly by site, which was in accordance with the soil physicochemical compositions. At both the phylum and species levels, bacterial community structure was explained primarily by pH and water content, while certain earth elements and trace metals also played important roles in shaping community variation. The higher heterogeneity of the bacterial community structure found at this site indicates how soil bacterial communities have adapted to different compositions of edaphic variables under extreme environmental conditions. Taken together, these findings greatly advance our understanding of the adaption of soil bacterial populations to this harsh environment.

  18. Load balancing in highly parallel processing of Monte Carlo code for particle transport

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Kenji; Takemiya, Hiroshi [Japan Atomic Energy Research Inst., Tokyo (Japan); Kawasaki, Takuji [Fuji Research Institute Corporation, Tokyo (Japan)

    2001-01-01

    In parallel processing of Monte Carlo(MC) codes for neutron, photon and electron transport problems, particle histories are assigned to processors making use of independency of the calculation for each particle. Although we can easily parallelize main part of a MC code by this method, it is necessary and practically difficult to optimize the code concerning load balancing in order to attain high speedup ratio in highly parallel processing. In fact, the speedup ratio in the case of 128 processors remains in nearly one hundred times when using the test bed for the performance evaluation. Through the parallel processing of the MCNP code, which is widely used in the nuclear field, it is shown that it is difficult to attain high performance by static load balancing in especially neutron transport problems, and a load balancing method, which dynamically changes the number of assigned particles minimizing the sum of the computational and communication costs, overcomes the difficulty, resulting in nearly fifteen percentage of reduction for execution time. (author)

  19. Light weight design of highly loaded components requires matching load assumptions; Leichtbau hoch beanspruchter Bauteile erfordert angepasste rechnerische Bauteilbemessung

    Energy Technology Data Exchange (ETDEWEB)

    Heinrietz, A.; Ehl, O. [Fraunhofer-Institut fuer Betriebsfestigkeit (LBF), Darmstadt (Germany); Hasselberg, P. [Volvo Truck Corporation (Sweden); Hamm, C.E. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Bereich Plankton Biomechanik und Marine Bionik

    2007-07-01

    The aim of safe light weight design requires increasing efforts for component design in the design process. A significant change of the component's topology in order to reach the aim of light weight design may lead to unsafe components, taking customer use into account. The component's light weight shape may become more sensitive to varying operational loads or to varying adjacent components. Computational methods can support the way to light weight design in an efficient way. (orig.)

  20. DM100 AND DM1200 MELTER TESTING WITH HIGH WASTE LOADING GLASS FORMULATIONS FOR HANFORD HIGH-ALUMINUM HLW STREAMS

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; MATLACK KS; KOT WK; PEGG IL; JOSEPH I

    2009-12-30

    This Test Plan describes work to support the development and testing of high waste loading glass formulations that achieve high glass melting rates for Hanford high aluminum high level waste (HLW). In particular, the present testing is designed to evaluate the effect of using low activity waste (LAW) waste streams as a source of sodium in place ofchemical additives, sugar or cellulose as a reductant, boehmite as an aluminum source, and further enhancements to waste processing rate while meeting all processing and product quality requirements. The work will include preparation and characterization of crucible melts in support of subsequent DuraMelter 100 (DM 100) tests designed to examine the effects of enhanced glass formulations, glass processing temperature, incorporation of the LAW waste stream as a sodium source, type of organic reductant, and feed solids content on waste processing rate and product quality. Also included is a confirmatory test on the HLW Pilot Melter (DM1200) with a composition selected from those tested on the DM100. This work builds on previous work performed at the Vitreous State Laboratory (VSL) for Department of Energy's (DOE's) Office of River Protection (ORP) to increase waste loading and processing rates for high-iron HLW waste streams as well as previous tests conducted for ORP on the same waste composition. This Test Plan is prepared in response to an ORP-supplied statement of work. It is currently estimated that the number of HLW canisters to be produced in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is about 12,500. This estimate is based upon the inventory ofthe tank wastes, the anticipated performance of the sludge treatment processes, and current understanding of the capability of the borosilicate glass waste form. The WTP HLW melter design, unlike earlier DOE melter designs, incorporates an active glass bubbler system. The bubblers create active glass pool convection and thereby improve heat

  1. High gas pressure: an innovative method for the inactivation of dried bacterial spores.

    Science.gov (United States)

    Colas de la Noue, A; Espinasse, V; Perrier-Cornet, J-M; Gervais, P

    2012-08-01

    In this article, an original non-thermal process to inactivate dehydrated bacterial spores is described. The use of gases such as nitrogen or argon as transmission media under high isostatic pressure led to an inactivation of over 2 logs CFU/g of Bacillus subtilis spores at 430 MPa, room temperature, for a 1 min treatment. A major requirement for the effectiveness of the process resided in the highly dehydrated state of the spores. Only a water activity below 0.3 led to substantial inactivation. The solubility of the gas in the lipid components of the spore and its diffusion properties was essential to inactivation. The main phenomenon involved seems to be the sorption of the gas under pressure by the spores' structures such as residual pores and plasma membranes, followed by a sudden drop in pressure. Observation by phase-contrast microscopy suggests that internal structures have been affected by the treatment. Some parallels with polymer permeability to gas and rigidity at various water activities offer a few clues about the behavior of the outer layers of spores in response to this parameter and provide a good explanation for the sensitivity of spores to high gas pressure discharge at low hydration levels. Specificity of microorganisms such as size, organization, and composition could help in understanding the differences between spores and yeast regarding the parameters required for inactivation, such as pressure or maintenance time.

  2. Numerical Simulation and Validation of a High Head Model Francis Turbine at Part Load Operating Condition

    Science.gov (United States)

    Goyal, Rahul; Trivedi, Chirag; Kumar Gandhi, Bhupendra; Cervantes, Michel J.

    2017-07-01

    Hydraulic turbines are operated over an extended operating range to meet the real time electricity demand. Turbines operated at part load have flow parameters not matching the designed ones. This results in unstable flow conditions in the runner and draft tube developing low frequency and high amplitude pressure pulsations. The unsteady pressure pulsations affect the dynamic stability of the turbine and cause additional fatigue. The work presented in this paper discusses the flow field investigation of a high head model Francis turbine at part load: 50% of the rated load. Numerical simulation of the complete turbine has been performed. Unsteady pressure pulsations in the vaneless space, runner, and draft tube are investigated and validated with available experimental data. Detailed analysis of the rotor stator interaction and draft tube flow field are performed and discussed. The analysis shows the presence of a rotating vortex rope in the draft tube at the frequency of 0.3 times of the runner rotational frequency. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations in the draft tube, is predicted within 3.9% of the experimental measured value. The vortex rope results pressure pulsations propagating in the system whose frequency is also perceive in the runner and upstream the runner.

  3. HIGH SOLID AND LOW ENZYME LOADING BASED SACCHARIFICATION OF AGRICULTURAL BIOMASS

    Directory of Open Access Journals (Sweden)

    Yu Zhang,

    2011-11-01

    Full Text Available Two agricultural biomass materials, namely wheat straw and sugarcane bagasse, were pretreated with NaOH and then used as substrates for enzymatic saccharification. After the pretreatment, the increase in glucan content and the decrease in lignin content were more than 65%, while less than 20% increase occurred in xylan content. The enzymatic saccharification was initiated with solid loading 9% (w/v, and then 8%, 7% and 6% (w/v solid was fed at 8, 24, and 48 h, respectively. The final enzyme solid loading was 9.60 FPU/g solid and 30% (w/v, respectively. At 144 h, the produced glucose, xylose, and reducing sugar concentrations for wheat straw were 81.88, 20.30, and 115.25 g/L, respectively, and for sugarcane bagasse they were 125.97, 8.66, and 169.50 g/L, respectively. The final conversions of wheat straw and sugarcane bagasse were 34.57% and 50.85%, respectively. SEM images showed that the surface structure of the two materials changed a lot via alkali-pretreatment and enzymatic hydrolysis. In summary, a high concentration sugar is produced from the two agricultural biomass materials by high solid and low enzyme loading. Compared to wheat straw, sugarcane bagasse is more suitable for use in sugar production.

  4. Residual stress in a M3:2 PM high speed steel; effect of mechanical loading

    DEFF Research Database (Denmark)

    Højerslev, Christian; Odén, Magnus; Carstensen, Jesper V.

    2001-01-01

    X-ray lattice strains were investigated in an AISI M3:2 PM high-speed steel in the as heat treated condition and after exposure to alternating mechanical load. The volume changes during heat treatment were monitored with dilatometry. Hardened and tempered AISI M3:2 steel consists of tempered lath...... martensite and the carbides M6C,V8C7 and M23C6. In the as heat treated condition the stress state is triaxial. The primary carbides M6C and V8C7 experience a compressive state of stress. Exposure to an alternating mechanical load, changes the states of stress of V8C7 and tempered martensite, but does...... not appear to change the state of stress in M6C....

  5. Study of stress ratio effect on titanium alloy fatigue under high-frequency loading

    Energy Technology Data Exchange (ETDEWEB)

    Voznyj, T.S.; Gurvich, Yu.V.; Kirillov, V.I.; Troyan, I.A. (AN Ukrainskoj SSR, Kiev. Inst. Problem Prochnosti)

    1983-02-01

    Endurance of two titanium alloys, OT4 type ..cap alpha..-alloy and VT6 martensite class, (..cap alpha..+..beta..)-alloy was studied under symmetric and asymmetric tension-compression at 10 kHz frequency and room temperature using a magnetostriction resonance device. The tests were carried out in the air without water cooling usual in high-frequency tests, since a very low hysteresis dissipation of energy was observed under cyclic loading near the fatigue limit of these titanium alloys. Fatigue curves are obtained on the basis of 10/sup 9/ cycles. The ratio is found for the endurance limit based on 10/sup 7/ and 10/sup 8/ cycles to the ultimate strength under symmetric loading. An equation is given which satisfactorily describes limiting amplitude diagrams, and its coefficients are analyzed.

  6. Assessment of Gearbox Operational Loads and Reliability under High Mean Wind Speeds

    DEFF Research Database (Denmark)

    Dabrowski, Dariusz; Natarajan, Anand

    2015-01-01

    wind turbine that operates in storm conditions with mean wind speeds less than 30 m/s is presented. In the study, normal shut-downs of a wind turbine in storm conditions were investigated. The analysis were conducted for two storm control strategies and different wind conditions from an extreme...... of the model was based on the experimental data provided by NREL for 750 kW prototype gearbox. Failures of gearboxes caused by high dynamic loads have a significant influence on the cost of operation of wind farms. For these reasons in the study, the probability of failure of the gearbox working in an offshore...... operating gust, normal turbulence model and extreme turbulence model. In the paper, loads in the planetary gear are quantified as well as the torsional moments in the main shaft. On the basis of simulation results the annual probability of failure of the gearbox in a wind turbine with soft storm controller...

  7. Design and identification of high performance steel alloys for structures subjected to underwater impulsive loading

    Science.gov (United States)

    Wei, Xiaoding; Latourte, Felix; Feinberg, Zack; Olson, Gregory; Espinosa, Horacio; Micro; Nanomechanics Laboratory Team; Olson Group Team

    2011-06-01

    To characterize the performance of naval structures, underwater blast experiments have been developed. Martensitic and austenitic steel alloys were designed to optimize the performance of structures subjected to impulsive loads. The deformation and fracture characteristics of the designed steel alloys were investigated experimentally and computationally. The experiments were based on an instrumented fluid structure interaction apparatus, in which deflection profiles were recorded. The computational study was based on a modified Gurson damage model able to accurately describe ductile failure under various loading paths. The model was calibrated for two high performance martensitic steels (HSLA-100 and BA-160) and an austenitic steel (TRIP-120). The martensitic steel (BA-160) was designed to maximize strength and fracture toughness while the austenitic steel (TRIP-120) was designed to maximize uniform ductility. The combined experimental-computational approach provided insight into the relationships between material properties and blast resistance of structures.

  8. High-Velocity Impact Behaviour of Prestressed Composite Plates under Bird Strike Loading

    Directory of Open Access Journals (Sweden)

    Sebastian Heimbs

    2012-01-01

    Full Text Available An experimental and numerical analysis of the response of laminated composite plates under high-velocity impact loads of soft body gelatine projectiles (artificial birds is presented. The plates are exposed to tensile and compressive preloads before impact in order to cover realistic loading conditions of representative aeronautic structures under foreign object impact. The modelling methodology for the composite material, delamination interfaces, impact projectile, and preload using the commercial finite element code Abaqus are presented in detail. Finally, the influence of prestress and of different delamination modelling approaches on the impact response is discussed and a comparison to experimental test data is given. Tensile and compressive preloading was found to have an influence on the damage pattern. Although this general behaviour could be predicted well by the simulations, further numerical challenges for improved bird strike simulation accuracy are highlighted.

  9. Automated load balancing in the ATLAS high-performance storage software

    CERN Document Server

    Le Goff, Fabrice; The ATLAS collaboration

    2017-01-01

    The ATLAS experiment collects proton-proton collision events delivered by the LHC accelerator at CERN. The ATLAS Trigger and Data Acquisition (TDAQ) system selects, transports and eventually records event data from the detector at several gigabytes per second. The data are recorded on transient storage before being delivered to permanent storage. The transient storage consists of high-performance direct-attached storage servers accounting for about 500 hard drives. The transient storage operates dedicated software in the form of a distributed multi-threaded application. The workload includes both CPU-demanding and IO-oriented tasks. This paper presents the original application threading model for this particular workload, discussing the load-sharing strategy among the available CPU cores. The limitations of this strategy were reached in 2016 due to changes in the trigger configuration involving a new data distribution pattern. We then describe a novel data-driven load-sharing strategy, designed to automatical...

  10. Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions.

    Science.gov (United States)

    Singh, Kiran; Giri, B S; Sahi, Amrita; Geed, S R; Kureel, M K; Singh, Sanjay; Dubey, S K; Rai, B N; Kumar, Surendra; Upadhyay, S N; Singh, R S

    2017-10-01

    The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm(-3)h(-1). The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65-98.7% and the maximum elimination capacity (EC) was 405.7gm(-3)h(-1). Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Ionic modified crosslinked salep: a highly loaded and efficient heterogeneous organocatalyst.

    Science.gov (United States)

    Pourjavadi, Ali; Hosseini, Seyed Hassan; Fakoorpoor, Seyed Mahmoud

    2013-02-15

    In this work, a novel heterogeneous organocatalyst was synthesized by immobilization of hydroxide ions on the modified salep as a natural polymer. Because of the grafting of ionic polymer chains onto the salep backbone, catalyst has high loading level of hydroxide ions (3.01 mmol/g). The resulting catalyst shows excellent activity in the synthesis of 4H-benzo[b]pyrans in water at room temperature in short reaction times. The present catalyst and protocol represent a simple, ecologically safe and cost-effective route to synthesize 4H-benzo[b]pyrans with high product yield, as well as easy catalyst recycling.

  12. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    Science.gov (United States)

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S.; Ellis, Tom

    2016-03-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity.

  13. Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds under Lap Shear Loading Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2008-06-01

    This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS) under lap shear loading condition. DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. Static weld strength tests using lap shear samples were performed on the joint populations with various fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with conventionally required fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 welds under lap shear loading. Moreover, failure mode has strong influence on weld peak load and energy absorption for all the DP800 welds and the TRIP800 small welds: welds failed in pullout mode have statistically higher strength and energy absorption than those failed in interfacial fracture mode. For TRIP800 welds above the critical fusion zone level, the influence of weld failure modes on peak load and energy absorption diminishes. Scatter plots of peak load and energy absorption versus weld fusion zone size were then constructed, and the results indicate that fusion zone size is the most critical factor in weld quality in terms of peak load and energy absorption for both DP800 and TRIP800 spot welds.

  14. Cooling performance of grid-sheets for highly loaded ultra-supercritical steam turbines

    Institute of Scientific and Technical Information of China (English)

    Dieter BOHN; Robert KREWINKEL; Shuqing TIAN

    2009-01-01

    In order to increase efficiency and achieve a further CO2-reduction, the next generation of power plant turbines will have steam turbine inlet temperatures that are considerably higher than the current ones. The high pressure steam turbine inlet temperature is expected to be increased up to approximately 700℃ with a live steam pressure of 30 MPa. The elevated steam parameters in the high and intermediate pressure turbines can be encountered with Ni-base alloys, but this is a costly alternative associated with many manufacturing difficulties. Colla-borative research centre 561 "Thermally Highly Loaded,Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants" at RWTH Aachen University proposes cooling the highly loaded turbines instead, as this would necessitate the application of far less Ni-base alloys.To protect the thermally highly loaded components, a sandwich material consisting of two thin face sheets and a core made from a woven wire mesh is used to cover the walls of the steam turbine casing. The cooling steam is led through the woven wire mesh between the two face sheets to achieve a cooling effect. The wire mesh provides the grid-sheet with structural rigidity under varying operating conditions.In the present work, the cooling performance of the grid-sheets will be investigated applying the conjugate heat transfer method to ultra-supercritical live and cooling steam conditions for a section of the cooling structure. The behaviour of the flow and the heat transfer in the grid-sheet will be analyzed in detail using a parameter variation. The numerical results should give a first prediction of the cooling performance under future operating conditions.

  15. Electrospinning of silver nanoparticles loaded highly porous cellulose acetate nanofibrous membrane for treatment of dye wastewater

    Science.gov (United States)

    Wang, Ke; Ma, Qian; Wang, Shu-Dong; Liu, Hua; Zhang, Sheng-Zhong; Bao, Wei; Zhang, Ke-Qin; Ling, Liang-Zhong

    2016-01-01

    In this paper, silver nanoparticles (NPs) were reduced form silver nitrate. Morphology and distribution of the synthesized silver NPs were characterized. In order to obtain cellulose acetate (CA), nanofibrous membrane with high effective adsorption performance to carry silver NPs for treatment of dye wastewater, different solvent systems were used to fabricate CA nanofibrous membranes with different morphologies and porous structures via electrospinning. Morphologies and structures of the obtained CA nanofibrous membranes were compared by scanning electron microscopy (SEM), which showed that CA nanofibrous membrane obtained from acetone/dichloromethane (1/2, v/v) was with the highly porous structure. SEM, energy-dispersive spectrometry and Fourier transform infrared spectrometry showed that the silver NPs were effectively incorporated in the CA nanofibrous membrane and the addition of silver NPs did not damage the porous structure of the CA nanofibrous membrane. Adsorption of dye solution (rhodamine B aqueous solution) revealed that the highly porous CA nanofibrous membrane exhibited effective adsorption performance and the addition of silver NPs did not affect the adsorption of the dye. Antibacterial property of the CA nanofibrous membrane showed that the silver-loaded highly porous CA nanofibrous membrane had remarkable antibacterial property when compared to the CA nanofibrous membrane without silver NPs. The silver-loaded highly porous CA nanofibrous membrane could be considered as an ideal candidate for treatment of the dye wastewater.

  16. Clinical efficacy of entecavir combined with adefovir in chronic hepatitis B patients with high viral load

    Directory of Open Access Journals (Sweden)

    ZHANG Wen

    2014-11-01

    Full Text Available ObjectiveTo investigate the efficacy and safety of entecavir (ETV combined with adefovir (ADV in chronic hepatitis B (CHB patients with high viral load. MethodsEighty CHB patients with high viral load who were admitted to our hospital from December 2008 to December 2011 were equally and randomly divided into observation group and control group. The control group was given ETV, while the observation group was treated with ETV combined with ADV. HBV DNA load, HBsAg or HBeAg seroconversion, alanine aminotransferase (ALT normalization, and adverse reactions before and after 3, 6, 12, and 24 months of treatment were evaluated. Comparison of continuous data between the two groups was made by independent-samples t test, and comparison of categorical data was made by chi-square test. ResultsCompared with the control group, the observation group had significantly lower HBV DNA load after 6, 12, and 24 months of treatment (3.7±0.3 vs 3.4±0.4 log copies/ml, t=3.339, P<0.05; 2.9±0.4 vs 2.6±0.3 log copies/ml, t=5.657, P<0.05; 1.6±0.7 vs 1.2±0.4 log copies/ml, t=2.806, P<0.05. The HBV DNA clearance rate and HBeAg clearance rate in observation group were significantly higher than those in control group after 12 months of treatment (87.5% vs 70.0%, P<0.05; 80.0% vs 55.0%, P<0.05 and 24 months of treatment (95.0% vs 77.5%, P<0.05; 90.0% vs 70.0%, P<0.05. The observation group had significantly higher HBeAg seroconversion rate and ALT normalization rate than the control group after 24 months of treatment (77.5% vs 50.0%, P<0.05; 82.5% vs 55.0% P<005. During the treatment, there was no significant difference in the incidence of adverse reactions between the two groups (P>0.05, but the observation group had a significantly lower viral breakthrough rate than the control group (0 vs 10.0%, P<0.05. ConclusionFor CHB patients with high viral load, ETV combined with ADV has strong antiviral activity, reduces drug resistance and poor

  17. PIPE-chipSAD: a pipeline for the analysis of high density arrays of bacterial transcriptomes

    Directory of Open Access Journals (Sweden)

    Silvia Bottini

    2016-12-01

    Full Text Available PIPE-chipSAD is a pipeline for bacterial transcriptome studies based on high-density microarray experiments. The main algorithm chipSAD, integrates the analysis of the hybridization signal with the genomic position of probes and identifies portions of the genome transcribing for mRNAs. The pipeline includes a procedure, align-chipSAD, to build a multiple alignment of transcripts originating in the same locus in multiple experiments and provides a method to compare mRNA expression across different conditions. Finally, the pipeline includes anno-chipSAD a method to annotate the detected transcripts in comparison to the genome annotation. Overall, our pipeline allows transcriptional profile analysis of both coding and non-coding portions of the chromosome in a single framework. Importantly, due to its versatile characteristics, it will be of wide applicability to analyse, not only microarray signals, but also data from other high throughput technologies such as RNA-sequencing.The current PIPE-chipSAD implementation is written in Python programming language and is freely available at https://github.com/silviamicroarray/chipSAD.

  18. Experimental research on behavior of 460 MPa high strength steel I-section columns under cyclic loading

    Science.gov (United States)

    Wang, Jiaojiao; Shi, Gang; Shi, Yongjiu

    2014-12-01

    To investigate the seismic behavior of I-section columns made of 460 MPa high strength steel (HSS), six specimens were tested under constant axial load and cyclic horizontal load. The specimens were designed with different width-to-thickness ratios and loaded under different axial load ratios. For each specimen, the failure mode was observed and hysteretic curve was measured. Comparison of different specimens on hysteretic characteristic, energy dissipation capacity and deformation capacity were further investigated. Test results showed that the degradation of bearing capacity was due to local buckling of flange and web. Under the same axial load ratio, as width-to-thickness ratio increased, the deformation area of local buckling became smaller. And also, displacement level at both peak load and failure load became smaller. In addition, the full extent of hysteretic curve, energy dissipation capacity, ultimate story drift angle decreased, and capacity degradation occurred more rapidly with the increase of width-to-thickness ratio or axial load ratio. Based on the capacity of story drift angle, limiting values which shall not be exceeded are suggested respectively for flange and web plate of 460 MPa HSS I-section columns when used in SMFs and in IMFs in the case of axial load ratio no more than 0.2. Such values should be smaller when the axial load ratio increases.

  19. Association of running manner with bacterial community dynamics in a partial short-term nitrifying bioreactor for treatment of piggery wastewater with high ammonia content.

    Science.gov (United States)

    Du, Wei-Li; Huang, Qiang; Miao, Li-Li; Liu, Ying; Liu, Zhi-Pei

    2016-12-01

    Optimization of running parameters in a bioreactor requires detailed understanding of microbial community dynamics during the startup and running periods. Using a novel piggery wastewater treatment system termed "UASB + SHARON + ANAMMOX" constructed in our laboratory, we investigated microbial community dynamics using the Illumina MiSeq method, taking activated sludge samples at ~2-week intervals during a ~300-day period. Ammonia-oxidizing bacteria (AOB) were further investigated by quantification of AOB amoA genes and construction of gene clone libraries. Major changes in bacterial community composition and dynamics occurred when running manner was changed from continuous flow manner (CFM) to sequencing batch manner (SBM), and when effluent from an upflow anaerobic sludge blanket (UASB) reactor for practical treatment of real piggery wastewater was used as influent; differences among these three experimental groups were significant (R (2)  = 0.94, p level thereafter. Relative abundance of the genus Nitrosomonas increased from ~0.67 % during the CFM period to 8.0 % by day 220, and thereafter decreased to a near-constant ~1.6 %. Environmental factors such as load ammonia, effluent ammonia, effluent nitrite, UASB effluent, pH, and DO levels collectively drove bacterial community dynamics and contributed to maintenance of effluent NH4 (+)-N/NO2 (-)-N ratio ~1. Theses results might provide useful clues for the control of the startup processes and maintaining high efficiency of such bioreactors.

  20. Growth-Based Bacterial Viability Assay for Interference-Free and High-Throughput Toxicity Screening of Nanomaterials.

    Science.gov (United States)

    Qiu, Tian A; Nguyen, Thu Ha Thi; Hudson-Smith, Natalie V; Clement, Peter L; Forester, Dona-Carla; Frew, Hilena; Hang, Mimi N; Murphy, Catherine J; Hamers, Robert J; Feng, Z Vivian; Haynes, Christy L

    2017-02-07

    Current high-throughput approaches evaluating toxicity of chemical agents toward bacteria typically rely on optical assays, such as luminescence and absorbance, to probe the viability of the bacteria. However, when applied to toxicity induced by nanomaterials, scattering and absorbance from the nanomaterials act as interferences that complicate quantitative analysis. Herein, we describe a bacterial viability assay that is free of optical interference from nanomaterials and can be performed in a high-throughput format on 96-well plates. In this assay, bacteria were exposed to various materials and then diluted by a large factor into fresh growth medium. The large dilution ensured minimal optical interference from the nanomaterial when reading optical density, and the residue left from the exposure mixture after dilution was confirmed not to impact the bacterial growth profile. The fractions of viable cells after exposure were allowed to grow in fresh medium to generate measurable growth curves. Bacterial viability was then quantitatively correlated to the delay of bacterial growth compared to a reference regarded as 100% viable cells; data analysis was inspired by that in quantitative polymerase chain reactions, where the delay in the amplification curve is correlated to the starting amount of the template nucleic acid. Fast and robust data analysis was achieved by developing computer algorithms carried out using R. This method was tested on four bacterial strains, including both Gram-negative and Gram-positive bacteria, showing great potential for application to all culturable bacterial strains. With the increasing diversity of engineered nanomaterials being considered for large-scale use, this high-throughput screening method will facilitate rapid screening of nanomaterial toxicity and thus inform the risk assessment of nanoparticles in a timely fashion.

  1. Hippocampal NMDA receptors are involved in rats' spontaneous object recognition only under high memory load condition.

    Science.gov (United States)

    Sugita, Manami; Yamada, Kazuo; Iguchi, Natsumi; Ichitani, Yukio

    2015-10-22

    The possible involvement of hippocampal N-methyl-D-aspartate (NMDA) receptors in spontaneous object recognition was investigated in rats under different memory load conditions. We first estimated rats' object memory span using 3-5 objects in "Different Objects Task (DOT)" in order to confirm the highest memory load condition in object recognition memory. Rats were allowed to explore a field in which 3 (3-DOT), 4 (4-DOT), or 5 (5-DOT) different objects were presented. After a delay period, they were placed again in the same field in which one of the sample objects was replaced by another object, and their object exploration behavior was analyzed. Rats could differentiate the novel object from the familiar ones in 3-DOT and 4-DOT but not in 5-DOT, suggesting that rats' object memory span was about 4. Then, we examined the effects of hippocampal AP5 infusion on performance in both 2-DOT (2 different objects were used) and 4-DOT. The drug treatment before the sample phase impaired performance only in 4-DOT. These results suggest that hippocampal NMDA receptors play a critical role in spontaneous object recognition only when the memory load is high.

  2. Transient pressure measurements at part load operating condition of a high head model Francis turbine

    Indian Academy of Sciences (India)

    RAHUL GOYAL; CHIRAG TRIVEDI; B K GANDHI; MICHEL J CERVANTES; OLE G DAHLHAUG

    2016-11-01

    Hydraulic turbines are operating at part load conditions depending on availability of hydraulic energy or to meet the grid requirements. The turbine experiences more fatigue during the part load operating conditions due to flow phenomena such as vortex breakdown in the draft tube and flow instability in the runner.The present paper focuses on the investigation of a high head model Francis turbine operating at 50% load.Pressure measurements have been carried out experimentally on a model Francis turbine. Total six pressure sensors were mounted inside the turbine and other two pressure sensors were mounted at the turbine inlet pipe. It is observed that the turbine experiences significant pressure fluctuations at the vaneless space and the runner.Moreover, a standing wave is observed between the pressure tank outlet and the turbine inlet. Analysis of the data acquired by the pressure sensors mounted in the draft tube showed the presence of vortex breakdown corotating with the runner. The detailed analysis showed the rotating and plunging components of the vortex breakdown. The influence of the rotating component was observed in the entire hydraulic circuit includingdistributor and turbine inlet but not the plunging one.

  3. Charge-Reversal APTES-Modified Mesoporous Silica Nanoparticles with High Drug Loading and Release Controllability.

    Science.gov (United States)

    Wang, Yifeng; Sun, Yi; Wang, Jine; Yang, Yang; Li, Yulin; Yuan, Yuan; Liu, Changsheng

    2016-07-13

    In this study, we demonstrate a facile strategy (DL-SF) for developing MSN-based nanosystems through drug loading (DL, using doxorubicin as a model drug) followed by surface functionalization (SF) of mesoporous silica nanoparticles (MSNs) via aqueous (3-aminopropyl)triethoxysilane (APTES) silylation. For comparison, a reverse functionalization process (i.e., SF-DL) was also studied. The pre-DL process allows for an efficient encapsulation (encapsulation efficiency of ∼75%) of an anticancer drug [doxorubicin (DOX)] inside MSNs, and post-SF allows in situ formation of an APTES outer layer to restrict DOX leakage under physiological conditions. This method makes it possible to tune the DOX release rate by increasing the APTES decoration density through variation of the APTES concentration. However, the SF-DL approach results in a rapid decrease in drug loading capacity with an increase in APTES concentration because of the formation of the APTES outer layer hampers the inner permeability of the DOX drug, resulting in a burst release similar to that of undecorated MSNs. The resulting DOX-loaded DL-SF MSNs present a slightly negatively charged surface under physiological conditions and become positively charged in and extracellular microenvironment of solid tumor due to the protonation effect under acidic conditions. These merits aid their maintenance of long-term stability in blood circulation, high cellular uptake by a kind of skin carcinoma cells, and an enhanced intracellular drug release behavior, showing their potential in the delivery of many drugs beyond anticancer chemotherapeutics.

  4. Particle Concentration and Yield Stress of Biomass Slurries During Enzymatic Hydrolysis at High-Solids Loadings

    Energy Technology Data Exchange (ETDEWEB)

    Roche, C. M.; Dibble, C. J.; Knutsen, J. S.; Stickel, J. J.; Liberatore, M. W.

    2009-01-01

    Effective and efficient breakdown of lignocellulosic biomass remains a primary barrier for its use as a feedstock for renewable transportation fuels. A more detailed understanding of the material properties of biomass slurries during conversion is needed to design cost-effective conversion processes. A series of enzymatic saccharification experiments were performed with dilute acid pretreated corn stover at initial insoluble solids loadings of 20% by mass, during which the concentration of particulate solids and the rheological property yield stress ({tau}{sub y}) of the slurries were measured. The saccharified stover liquefies to the point of being pourable ({tau}{sub y} {le} 10 Pa) at a total biomass conversion of about 40%, after roughly 2 days of saccharification for a moderate loading of enzyme. Mass balance and semi-empirical relationships are developed to connect the progress of enzymatic hydrolysis with particle concentration and yield stress. The experimental data show good agreement with the proposed relationships. The predictive models developed here are based on established physical principles and should be applicable to the saccharification of other biomass systems. The concepts presented, especially the ability to predict yield stress from extent of conversion, will be helpful in the design and optimization of enzymatic hydrolysis processes that operate at high-solids loadings.

  5. Dynamics and Control of High-Rise Buildings under Multidirectional Wind Loads

    Directory of Open Access Journals (Sweden)

    Aly Mousaad Aly

    2011-01-01

    Full Text Available This paper presents a procedure for the response prediction and reduction in high-rise buildings under multidirectional wind loads. The procedure is applied to a very slender tall building that is instructive. The structure is exposed to both cross-wind and along-wind loads obtained from pressure measurements on a rigid model (scaled 1 : 100 that was tested in a wind tunnel with two different configurations of the surroundings. In the theoretical formulation, dynamic equations of the structure are introduced by finite element and 3D lumped mass modeling. The lateral responses of the building in the two directions are controlled at the same time using tuned mass dampers (TMDs and active tuned mass dampers (ATMDs commanded by LQR and fuzzy logic controllers, while the effects of the uncontrolled torsional response of the structure are simultaneously considered. Besides their simplicity, fuzzy logic controllers showed similar trend as LQR controllers under multidirectional wind loads. Nevertheless, the procedure presented in this study can help decision makers, involved in the design process, to choose among innovative solutions like structural control, different damping techniques, modifying geometry, or even changing materials.

  6. Bacterial diversity of a consortium degrading high-molecular-weight polycyclic aromatic hydrocarbons in a two-liquid phase biosystem.

    Science.gov (United States)

    Lafortune, Isabelle; Juteau, Pierre; Déziel, Eric; Lépine, François; Beaudet, Réjean; Villemur, Richard

    2009-04-01

    High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. Although several PAH-degrading bacterial species have been isolated, it is not expected that a single isolate would exhibit the ability to degrade completely all PAHs. A consortium composed of different microorganisms can better achieve this. Two-liquid phase (TLP) culture systems have been developed to increase the bioavailability of poorly soluble substrates for uptake and biodegradation by microorganisms. By combining a silicone oil-water TLP system with a microbial consortium capable of degrading HMW PAHs, we previously developed a highly efficient PAH-degrading system. In this report, we characterized the bacterial diversity of the consortium with a combination of culture-dependent and culture-independent methods. Polymerase chain reaction (PCR) of part of the 16S ribosomal RNA gene (rDNA) sequences combined with denaturing gradient gel electrophoresis was used to monitor the bacterial population changes during PAH degradation of the consortium when pyrene, chrysene, and benzo[a]pyrene were provided together or separately in the TLP cultures. No substantial changes in bacterial profiles occurred during biodegradation of pyrene and chrysene in these cultures. However, the addition of the low-molecular-weight PAHs phenanthrene or naphthalene in the system favored one bacterial species related to Sphingobium yanoikuyae. Eleven bacterial strains were isolated from the consortium but, interestingly, only one-IAFILS9 affiliated to Novosphingobium pentaromativorans-was capable of growing on pyrene and chrysene as sole source of carbon. A 16S rDNA library was derived from the consortium to identify noncultured bacteria. Among 86 clones screened, 20 were affiliated to different bacterial species-genera. Only three strains were represented in the screened clones. Eighty

  7. Constructing An Event Based Aerosol Product Under High Aerosol Loading Conditions

    Science.gov (United States)

    Levy, R. C.; Shi, Y.; Mattoo, S.; Remer, L. A.; Zhang, J.

    2016-12-01

    High aerosol loading events, such as the Indonesia's forest fire in Fall 2015 or the persistent wintertime haze near Beijing, gain tremendous interests due to their large impact on regional visibility and air quality. Understanding the optical properties of these events and further being able to simulate and predict these events are beneficial. However, it is a great challenge to consistently identify and then retrieve aerosol optical depth (AOD) from passive sensors during heavy aerosol events. Some reasons include:1). large differences between optical properties of high-loading aerosols and those under normal conditions, 2) spectral signals of optically thick aerosols can be mistaken with surface depending on aerosol types, and 3) Extremely optically thick aerosol plumes can also be misidentified as clouds due to its high optical thickness. Thus, even under clear-sky conditions, the global distribution of extreme aerosol events is not well captured in datasets such as the MODIS Dark-Target (DT) aerosol product. In this study, with the synthetic use of OMI Aerosol Index, MODIS cloud product, and operational DT product, the heavy smoke events over the seven sea region are identified and retrieved over the dry season. An event based aerosol product that would compensate the standard "global" aerosol retrieval will be created and evaluated. The impact of missing high AOD retrievals on the regional aerosol climatology will be studied using this newly developed research product.

  8. Flight Loads Prediction of High Aspect Ratio Wing Aircraft Using Multibody Dynamics

    Directory of Open Access Journals (Sweden)

    Michele Castellani

    2016-01-01

    Full Text Available A framework based on multibody dynamics has been developed for the static and dynamic aeroelastic analyses of flexible high aspect ratio wing aircraft subject to structural geometric nonlinearities. Multibody dynamics allows kinematic nonlinearities and nonlinear relationships in the forces definition and is an efficient and promising methodology to model high aspect ratio wings, which are known to be prone to structural nonlinear effects because of the high deflections in flight. The multibody dynamics framework developed employs quasi-steady aerodynamics strip theory and discretizes the wing as a series of rigid bodies interconnected by beam elements, representative of the stiffness distribution, which can undergo arbitrarily large displacements and rotations. The method is applied to a flexible high aspect ratio wing commercial aircraft and both trim and gust response analyses are performed in order to calculate flight loads. These results are then compared to those obtained with the standard linear aeroelastic approach provided by the Finite Element Solver Nastran. Nonlinear effects come into play mainly because of the need of taking into account the large deflections of the wing for flight loads computation and of considering the aerodynamic forces as follower forces.

  9. Release of Inattentional Blindness by High Working Memory Load: Elucidating the Relationship between Working Memory and Selective Attention

    Science.gov (United States)

    de Fockert, Jan W.; Bremner, Andrew J.

    2011-01-01

    An unexpected stimulus often remains unnoticed if attention is focused elsewhere. This inattentional blindness has been shown to be increased under conditions of high memory load. Here we show that increasing working memory load can also have the opposite effect of reducing inattentional blindness (i.e., improving stimulus detection) if stimulus…

  10. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Landman, I.S.; Pestchanyi, S.E.; Bazylev, B.N [Forschungszentrum Karlsruhe (Germany). Inst. for Pulsed Power and Microwave Technology; Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (TRINITI) (Russian Federation); Garkusha, I.E. [Kharkov Inst. of Physics and Technology (KIPT) (Ukraine). Inst. of Plasma Physics

    2004-08-01

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 10{sup 2} MJ/m{sup 2} on a time scale {tau} of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q {approx} 3MJ/m{sup 2} and {tau}{approx}0.3 ms; deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q=10-30MJ/m{sup 2} and {tau} = 0.03-0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  11. Effect of various loads on the force-time characteristics of the hang high pull.

    Science.gov (United States)

    Suchomel, Timothy J; Beckham, George K; Wright, Glenn A

    2015-05-01

    The purpose of this study was to investigate the effect of various loads on the force-time characteristics associated with peak power during the hang high pull (HHP). Fourteen athletic men (age: 21.6 ± 1.3 years; height: 179.3 ± 5.6 cm; body mass: 81.5 ± 8.7 kg; 1 repetition maximum [1RM] hang power clean [HPC]: 104.9 ± 15.1 kg) performed sets of the HHP at 30, 45, 65, and 80% of their 1RM HPC. Peak force, peak velocity, peak power, force at peak power, and velocity at peak power were compared between loads. Statistical differences in peak force (p = 0.001), peak velocity (p < 0.001), peak power (p = 0.015), force at peak power (p < 0.001), and velocity at peak power (p < 0.001) existed, with the greatest values for each variable occurring at 80, 30, 45, 80, and 30% 1RM HPC, respectively. Effect sizes between loads indicated that larger differences in velocity at peak power existed as compared with those displayed by force at peak power. It seems that differences in velocity may contribute to a greater extent to differences in peak power production as compared with force during the HHP. Further investigation of both force and velocity at peak power during weightlifting variations is necessary to provide insight on the contributing factors of power production. Specific load ranges should be prescribed to optimally train the variables associated with power development during the HHP.

  12. Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin.

    Science.gov (United States)

    Slane, Joshua; Gietman, Bradley; Squire, Matthew

    2017-09-06

    Two-stage revision treatment of prosthetic joint infection (PJI) frequently employs the use of a temporary bone cement spacer loaded with multiple antibiotic types. Tobramycin and vancomycin are commonly used antibiotics in cement spacers, however, there is no consensus on the relative concentrations and combinations that should be used. Therefore, the purpose of this study was to investigate the influence of dual antibiotic loading on the total antibiotic elution and compressive mechanical properties of acrylic bone cement. Varying concentrations of tobramycin (0-3 g) and vancomycin (0-3 g) were added either alone or in combination to acrylic cement (Palacos R), resulting in 12 experimental groups. Samples were submerged in 37°C saline for 28 d and sampled at specific time points. The collected eluent was analyzed to determine the cumulative antibiotic release. In addition, the cement's compressive mechanical properties and porosity were characterized. Interestingly, the cement with the highest concentration of antibiotics did not possess the best elution properties. Cement samples containing both 3 g of tobramycin and 2 g vancomycin demonstrated the highest cumulative antibiotic release after 28 d, which was coupled with a significant decrease in the mechanical properties and an increased porosity. The collected data also suggests that tobramycin elutes more effectively than vancomycin from cement. In conclusion, this study demonstrates that high antibiotic loading in cement does not necessarily lead to enhanced antibiotic elution. Clinically this information may be used to optimize cement spacer antibiotic loading so that both duration and amount of antibiotics eluted are optimized. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  13. Development of high drug-loading nanomicelles targeting steroids to the brain.

    Science.gov (United States)

    Zheng, Sijia; Xie, Yanqi; Li, Yuan; Li, Ling; Tian, Ning; Zhu, Wenbo; Yan, Guangmei; Wu, Chuanbin; Hu, Haiyan

    2014-01-01

    The objective of this research was to develop and evaluate high drug-loading ligand-modified nanomicelles to deliver a steroidal compound to the brain. YC1 (5α-cholestane-24-methylene-3β, 5α, 6β, 19-tetraol), with poor solubility and limited access to the brain, for the first time, has been proved to be an effective neuroprotective steroid by our previous studies. Based on the principle of 'like dissolves like', cholesterol, which shares the same steroidal parent nucleus with YC1, was selected to react with sodium alginate, producing amphiphilic sodium alginate- cholesterol derivatives (SACDs). To increase the grafting ratio and drug loading, cholesterol was converted to cholesteryl chloroformate, for the first time, before reacting with sodium alginate. Further, lactoferrin was conjugated on SACDs to provide lactoferrin-SACDs (Lf-SACD), which was established by immune electron microscopy (IEM) and self-assembled into brain-targeting nanomicelles. These nanomicelles were negatively charged and spherical in nature, with an average size of drug loading was increased due to the cholesteryl inner cores of the nanomicelles, and the higher the grafting ratio was, the lower the critical micelle concentration (CMC) value of SACD, and the higher drug loading. The in vitro drug release, studied by bulk-equilibrium dialysis in 20 mL of 6% hydroxypropyl-β-cyclodextrin solution at 37°C, indicated a prolonged release profile. The YC1 concentration in mouse brain delivered by lactoferrin-modified nanomicelles was higher than in those delivered by non-modified nanomicelles and YC1 solution. The unique brain-targeting nanomicelle system may provide a promising carrier to deliver hydrophobic drugs across the blood-brain barrier for the treatment of brain diseases.

  14. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Science.gov (United States)

    Landman, I. S.; Pestchanyi, S. E.; Safronov, V. M.; Bazylev, B. N.; Garkusha, I. E.

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 102 MJ/m 2 on a time scale Ïä of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q âe 1/4 3 MJ/m2 and Ïä âe 1/4 0.3 ms, deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q = 10–30 MJ/m2 and Ïä = 0.03–0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  15. A Method for Load Frequency Control using Battery in Power System with Highly Penetrated Photovoltaic Generation

    Science.gov (United States)

    Nagoya, Hiroyuki; Komami, Shintaro; Ogimoto, Kazuhiko

    It is generally believed that a large amount of battery system will be needed to store surplus electric energy due to high penetration of renewable energy (RE) such as photovoltaic generation (PV). Since main objective of high penetration of REs is to reduce amount of CO2 emission, reducing kWh output of thermal generation that does emit large amount of CO2 in power system should be considered sufficiently. However, thermal generation takes a important role in load frequency control (LFC) of power system. Therefore, if LFC could be done with battery and hydro generation, kWh output of thermal generation would be reduced significantly. This paper presents a method for LFC using battery in power system with highly penetrated PVs. Assessment of the effect of the proposed method would be made considering mutual smoothing effect of highly penetrated PVs.

  16. A high sensitivity wireless mass-loading surface acoustic wave DNA biosensor

    Science.gov (United States)

    Cai, Hua-Lin; Yang, Yi; Zhang, Yi-Han; Zhou, Chang-Jian; Guo, Cang-Ran; Liu, Jing; Ren, Tian-Ling

    2014-03-01

    In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

  17. Progressive high-load strength training compared with general low-load exercises in patients with rotator cuff tendinopathy: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Ingwersen, Kim G; Christensen, Robin; Sørensen, Lilli; Jørgensen, Hans Ri; Jensen, Steen Lund; Rasmussen, Sten; Søgaard, Karen; Juul-Kristensen, Birgit

    2015-01-27

    Shoulder pain is the third most common musculoskeletal disorder, often affecting people's daily living and work capacity. The most common shoulder disorder is the subacromial impingement syndrome (SIS) which, among other pathophysiological changes, is often characterised by rotator cuff tendinopathy. Exercise is often considered the primary treatment option for rotator cuff tendinopathy, but there is no consensus on which exercise strategy is the most effective. As eccentric and high-load strength training have been shown to have a positive effect on patella and Achilles tendinopathy, the aim of this trial is to compare the efficacy of progressive high-load exercises with traditional low-load exercises in patients with rotator cuff tendinopathy. The current study is a randomised, participant- and assessor-blinded, controlled multicentre trial. A total of 260 patients with rotator cuff tendinopathy will be recruited from three outpatient shoulder departments in Denmark, and randomised to either 12 weeks of progressive high-load strength training or to general low-load exercises. Patients will receive six individually guided exercise sessions with a physiotherapist and perform home-based exercises three times a week. The primary outcome measure will be change from baseline to 12 weeks in the patient-reported outcome Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Previous studies of exercise treatment for SIS have not differentiated between subgroups of SIS and have often had methodological flaws, making it difficult to specifically design target treatment for patients diagnosed with SIS. Therefore, it was considered important to focus on a subgroup such as tendinopathy, with a specific tailored intervention strategy based on evidence from other regions of the body, and to clearly describe the intervention in a methodologically strong study. The trial was registered with Clinicaltrials.gov ( NCT01984203 ) on 31 October 2013.

  18. Temperature calculations of heat loads in rotating target wheels exposed to high beam currents.

    Energy Technology Data Exchange (ETDEWEB)

    Greene, J. P.; Gabor, R.; Neubauer, J.

    2000-11-29

    In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or wobbled beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material.

  19. Influence of different SSF conditions on ethanol production from corn stover at high solids loadings

    DEFF Research Database (Denmark)

    Gladis, Arne; Bondesson, Pia-Maria; Galbe, Mats

    2015-01-01

    In this study, three different kinds of simultaneous saccharification and fermentation (SSF) of washed pretreated corn stover with water-insoluble solids (WIS) content of 20% were investigated to find which one resulted in highest ethanol yield at high-solids loadings. The different methods were...... batch SSF, prehydrolysis followed by batch SSF and fed-batch SSF. Batch-SSF resulted in an ethanol yield of 75-76% and an ethanol concentration of 53 g/L. Prehydrolysis prior to batch SSF did not improve the ethanol yield compared with batch SSF. Fedbatch SSF, on the other hand, increased the yield...

  20. Online Load Operating Mode of Oil Film Bearing in High Speed Wire Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    LI Yugui; PANG Siqing; HUANG Qingxue; WANG Jianmei; ZHAO Chunjiang

    2006-01-01

    To study the mechanism of burnt damage of oil film bearing in high-speed wire rolling mill, reasonable temperature sensors are designed and calibrated, pressure block of rolling mill has been transformed into pressure sensors. Online temperature and load of oil film bearing in a domestic precision rolling F15 have been tested. Consequently, a large sum of valuable test data was obtained. The distributions rules of pressure and temperature under continuous online rolling state are recorded in detail. Theoretical and experimental results are beneficial to damage mechanism of oil film bearing, thus its service life could be prolonged. Moreover, such results could provide an important reference for online test and control.

  1. Comparative survey of bacterial and archaeal communities in high arsenic shallow aquifers using 454 pyrosequencing and traditional methods.

    Science.gov (United States)

    Li, Ping; Jiang, Dawei; Li, Bing; Dai, Xinyue; Wang, Yanhong; Jiang, Zhou; Wang, Yanxin

    2014-12-01

    A survey of bacterial and archaeal community structure was carried out in 10 shallow tube wells in a high arsenic groundwater system located in Hetao Basin, Inner Mongolia by 16S rRNA gene based two-step nested PCR-DGGE, clone libraries and 454 pyrosequencing. 12 bacterial and 18 archaeal DGGE bands and 26-136 species-level OTUs were detected for all the samples. 299 bacterial and 283 archaeal 16S rRNA gene clones for two typical samples were identified by phylogenetic analysis. Most of the results from these different methods were consistent with the dominant bacterial populations. But the proportions of the microbial populations were mostly different and the bacterial communities in most of these samples from pyrosequencing were both more abundant and more diverse than those from the traditional methods. Even after quality filtering, pyrosequencing revealed some populations including Alishewanella, Sulfuricurvum, Arthrobacter, Sporosarcina and Algoriphagus which were not detected with traditional techniques. The most dominant bacterial populations in these samples identified as some arsenic, iron, nitrogen and sulfur reducing and oxidizing related populations including Acinetobacter, Pseudomonas, Flavobacterium, Brevundimonas, Massilia, Planococcus, and Aquabacterium and archaeal communities Nitrosophaera and Methanosaeta. Acinetobacter and Pseudomonas were distinctly abundant in most of these samples. Methanogens were found as the dominant archeal population with three methods. From the results of traditional methods, the dominant archaeal populations apparently changed from phylum Thaumarchaeota to Euryarchaeota with the arsenic concentrations increasing. But this structure dynamic change was not revealed with pyrosequencing. Our results imply that an integrated approach combining the traditional methods and next generation sequencing approaches to characterize the microbial communities in high arsenic groundwater is recommended.

  2. High specificity ZnO quantum dots for diagnosis and treatment in bacterial infection

    Science.gov (United States)

    Zhang, Min; Qian, Zhiyu; Gu, Yueqing

    2016-03-01

    Early diagnosis and effective treatment of bacterial infection has become increasingly important. Herein, we developed a fluorescent nano-probe MPA@ZnO-PEP by conjugating SiO2-stabilized ZnO quantum dot (ZnO@SiO2) with bacteria-targeting peptide PEP, which was encapsulated with MPA, a near infrared (NIR) dye. The nanoprobe MPA@ZnO-PEP showed excellent fluorescence property and could specifically distinguish bacterial infection from sterile inflammation both in vitro and in vivo. The favorable biocompatability of MPA@ZnO-PEP was verified by MTT assay. This probe was further modified with antibiotic methicillin to form the theranostic nanoparticle MPA/Met@ZnO-PEP with amplified antibacterial activity. These results promised the great potential of MPA@ZnO-PEP for efficient non-invasive early diagnosis of bacterial infections and effective bacterial-targeting therapy.

  3. High-throughput viability assay using an autonomously bioluminescent cell line with a bacterial Lux reporter.

    Science.gov (United States)

    Class, Bradley; Thorne, Natasha; Aguisanda, Francis; Southall, Noel; McKew, John C; Zheng, Wei

    2015-04-01

    Cell viability assays are extensively used to determine cell health, evaluate growth conditions, and assess compound cytotoxicity. Most existing assays are endpoint assays, in which data are collected at one time point after termination of the experiment. The time point at which toxicity of a compound is evident, however, depends on the mechanism of that compound. An ideal cell viability assay allows the determination of compound toxicity kinetically without having to terminate the assay prematurely. We optimized and validated a reagent-addition-free cell viability assay using an autoluminescent HEK293 cell line that stably expresses bacterial luciferase and all substrates necessary for bioluminescence. This cell viability assay can be used for real-time, long-term measurement of compound cytotoxicity in live cells with a signal-to-basal ratio of 20- to 200-fold and Z-factors of ~0.6 after 24-, 48- 72-, or 96-h incubation with compound. We also found that the potencies of nine cytotoxic compounds correlated well with those measured by four other commonly used cell viability assays. The results demonstrated that this kinetic cell viability assay using the HEK293(lux) autoluminescent cell line is useful for high-throughput evaluation of compound cytotoxicity.

  4. Freestanding bacterial cellulose-graphene oxide composite membranes with high mechanical strength for selective ion permeation

    Science.gov (United States)

    Fang, Qile; Zhou, Xufeng; Deng, Wei; Zheng, Zhi; Liu, Zhaoping

    2016-09-01

    Graphene oxide (GO) based membranes have been widely applied in molecular separation based on the size exclusion effect of the nanochannels formed by stacked GO sheets. However, it’s still a challenge to prepare a freestanding GO-based membrane with high mechanical strength and structural stability which is prerequisite for separation application in aqueous solution. Here, a freestanding composite membrane based on bacterial cellulose (BC) and GO is designed and prepared. BC network provides a porous skeleton to spread GO sheets and uniformly incorporates into the GO layers, which endows the BC + GO composite membrane with well water-stability, excellent tensile strength, as well as improved toughness, guaranteeing its separation applicability in water environment. The resulting BC + GO membrane exhibits obviously discrepant permeation properties for different inorganic/organic ions with different size, and in particular, it can quickly separate ions in nano-scale from angstrom-scale. Therefore, this novel composite membrane is considered to be a promising candidate in the applications of water purification, food industry, biomedicine, and pharmaceutical and fuel separation.

  5. High Dynamic Range Color Image Enhancement Using Fuzzy Logic and Bacterial Foraging

    Directory of Open Access Journals (Sweden)

    Om Prakash Verma

    2011-09-01

    Full Text Available High dynamic range images contain both the underexposed and the overexposed regions. The enhancement of the underexposed and the overexposed regions is the main concern of this paper. Two new transformation functions are proposed to modify the fuzzy membership values of under and the overexposed regions of an image respectively.For the overexposed regions, a rectangular hyperbolic function is used while for the underexposed regions, an S-function is applied. The shape and range of these functions can be controlled by the parameters involved, which are optimized using the bacterial foraging optimization algorithm so as to obtain the enhanced image. The hue, saturation, and intensity (HSV color space is employed for the purpose of enhancement, where the hue component is preserved to keep the original color composition intact. This approach is applicable to a degraded image of mixed type. On comparison, the proposed transforms yield better results than the existing transformation functions17 for both the underexposed and the overexposed regions.Defence Science Journal, 2011, 61(5, pp.462-472, DOI:http://dx.doi.org/10.14429/dsj.61.1184

  6. Freestanding bacterial cellulose-graphene oxide composite membranes with high mechanical strength for selective ion permeation

    Science.gov (United States)

    Fang, Qile; Zhou, Xufeng; Deng, Wei; Zheng, Zhi; Liu, Zhaoping

    2016-01-01

    Graphene oxide (GO) based membranes have been widely applied in molecular separation based on the size exclusion effect of the nanochannels formed by stacked GO sheets. However, it’s still a challenge to prepare a freestanding GO-based membrane with high mechanical strength and structural stability which is prerequisite for separation application in aqueous solution. Here, a freestanding composite membrane based on bacterial cellulose (BC) and GO is designed and prepared. BC network provides a porous skeleton to spread GO sheets and uniformly incorporates into the GO layers, which endows the BC + GO composite membrane with well water-stability, excellent tensile strength, as well as improved toughness, guaranteeing its separation applicability in water environment. The resulting BC + GO membrane exhibits obviously discrepant permeation properties for different inorganic/organic ions with different size, and in particular, it can quickly separate ions in nano-scale from angstrom-scale. Therefore, this novel composite membrane is considered to be a promising candidate in the applications of water purification, food industry, biomedicine, and pharmaceutical and fuel separation. PMID:27615451

  7. Bioremediation potential of a highly mercury resistant bacterial strain Sphingobium SA2 isolated from contaminated soil.

    Science.gov (United States)

    Mahbub, Khandaker Rayhan; Krishnan, Kannan; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    A mercury resistant bacterial strain, SA2, was isolated from soil contaminated with mercury. The 16S rRNA gene sequence of this isolate showed 99% sequence similarity to the genera Sphingobium and Sphingomonas of α-proteobacteria group. However, the isolate formed a distinct phyletic line with the genus Sphingobium suggesting the strain belongs to Sphingobium sp. Toxicity studies indicated resistance to high levels of mercury with estimated EC50 values 4.5 mg L(-1) and 44.15 mg L(-1) and MIC values 5.1 mg L(-1) and 48.48 mg L(-1) in minimal and rich media, respectively. The strain SA2 was able to volatilize mercury by producing mercuric reductase enzyme which makes it potential candidate for remediating mercury. ICP-QQQ-MS analysis of Hg supplemented culture solutions confirmed that almost 79% mercury in the culture suspension was volatilized in 6 h. A very small amount of mercury was observed to accumulate in cell pellets which was also evident according to ESEM-EDX analysis. The mercuric reductase gene merA was amplified and sequenced. The deduced amino acid sequence demonstrated sequence homology with α-proteobacteria and Ascomycota group.

  8. On the performance of circular concrete-filled high strength steel columns under axial loading

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmoud El-Heweity

    2012-06-01

    Full Text Available This work presents a numerical study to investigate the performance of circular high-strength steel tubes filled with concrete (CFT under monotonic axial loading. A model is developed to implement the material constitutive relationships and non-linearity. Calibration against previous experimental data shows good agreement. A parametric study is then conducted using the model and compared with codes provisions. Strength and ductility of confined concrete are of primary concern. Variables considered are yield stress of steel tube and column diameter. The assessment of column performance is based on axial load carrying capacities and enhancements of both strength and ductility due to confinement. Two parameters namely strength enhancement factor (Kf and ductility index (μ are clearly defined and introduced for assessment. Results indicate that both concrete strength and ductility of CFT columns are enhanced but to different extents. The ductile behaviors are significantly evident. The increase in yield stress of steel tube has a minimal effect on concrete strength but pronounced effect on concrete ductility. However, reduction in ductility is associated with using high-tensile steel of Grade 70. The overall findings indicate that the use of high-strength tube in CFT columns is not promising. This finding may seriously be considered in seismic design.

  9. CO2–CH4 permeation in high zeolite 4A loading mixed matrix membranes

    KAUST Repository

    Adams, Ryan T.

    2011-02-01

    Mixed matrix membranes (MMMs) with low particle loadings have been shown to improve the properties of pure polymers for many gas separations. Comparatively few reports have been made for high particle loading (≥50vol.%) MMMs. In this work, CO2-CH4 feeds were used to study the potential of 50vol.% zeolite 4A-poly(vinyl acetate) (PVAc) MMMs for natural gas separations. A low CO2 partial pressure mixed feed probed MMM performance below the plasticization pressure of PVAc and a high CO2 partial pressure mixed feed probed MMM performance at industrially relevant conditions above the plasticization pressure.Under both mixed feed conditions at 35°C, substantial improvements in overall separation performance were observed. At low CO2 partial pressures, CO2 permeability roughly doubled with a nearly 50% increase in selectivity versus pure PVAc under the same conditions. For the high CO2 partial pressure feed, CO2 permeability remained effectively unchanged with a 63% increase in selectivity versus pure PVAc. Surprisingly, the performance of these PVAc based MMMs approached the properties of current " upper bound" polymers. Overall, this work shows that significantly improved performance MMMs can be made with traditional techniques from a low cost, low performance polymer without costly adhesion promoters. © 2010.

  10. Highly Heterogeneous Soil Bacterial Communities around Terra Nova Bay of Northern Victoria Land, Antarctica

    OpenAIRE

    Mincheol Kim; Ahnna Cho; Hyoun Soo Lim; Soon Gyu Hong; Ji Hee Kim; Joohan Lee; Taejin Choi; Tae Seok Ahn; Ok-Sun Kim

    2015-01-01

    Given the diminished role of biotic interactions in soils of continental Antarctica, abiotic factors are believed to play a dominant role in structuring of microbial communities. However, many ice-free regions remain unexplored, and it is unclear which environmental gradients are primarily responsible for the variations among bacterial communities. In this study, we investigated the soil bacterial community around Terra Nova Bay of Victoria Land by pyrosequencing and determined which environm...

  11. Bacterial vaginosis among women at high risk for HIV in Uganda: high rate of recurrent diagnosis despite treatment.

    Science.gov (United States)

    Francis, Suzanna C; Looker, Clare; Vandepitte, Judith; Bukenya, Justine; Mayanja, Yunia; Nakubulwa, Susan; Hughes, Peter; Hayes, Richard J; Weiss, Helen A; Grosskurth, Heiner

    2016-03-01

    Bacterial vaginosis (BV) is associated with increased risk for sexually transmitted infections (STIs) and HIV acquisition. This study describes the epidemiology of BV in a cohort of women at high risk for STI/HIV in Uganda over 2 years of follow-up between 2008-2011. 1027 sex workers or bar workers were enrolled and asked to attend 3-monthly follow-up visits. Factors associated with prevalent BV were analysed using multivariate random-effects logistic regression. The effect of treatment on subsequent episodes of BV was evaluated with survival analysis. Prevalences of BV and HIV at enrolment were 56% (573/1027) and 37% (382/1027), respectively. Overall, 905 (88%) women tested positive for BV at least once in the study, over a median of four visits. Younger age, a higher number of previous sexual partners and current alcohol use were independently associated with prevalent BV. BV was associated with STIs, including HIV. Hormonal contraception and condom use were protective against BV. Among 853 treated BV cases, 72% tested positive again within 3 months. There was no difference in time to subsequent BV diagnosis between treated and untreated women. BV was highly prevalent and persistent in this cohort despite treatment. More effective treatment strategies are urgently needed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  12. Changes in the bacterial populations of the highly alkaline saline soil of the former lake Texcoco (Mexico) following flooding.

    Science.gov (United States)

    Valenzuela-Encinas, César; Neria-González, Isabel; Alcántara-Hernández, Rocio J; Estrada-Alvarado, Isabel; Zavala-Díaz de la Serna, Francisco Javier; Dendooven, Luc; Marsch, Rodolfo

    2009-07-01

    Flooding an extreme alkaline-saline soil decreased alkalinity and salinity, which will change the bacterial populations. Bacterial 16S rDNA libraries were generated of three soils with different electrolytic conductivity (EC), i.e. soil with EC 1.7 dS m(-1) and pH 7.80 (LOW soil), with EC 56 dS m(-1) and pH 10.11 (MEDIUM soil) and with EC 159 dS m(-1) and pH 10.02 (HIGH soil), using universal bacterial oligonucleotide primers, and 463 clone 16S rDNA sequences were analyzed phylogenetically. Library proportions and clone identification of the phyla Proteobacteria, Actinobacteria, Acidobacteria, Cyanobacteria, Bacteroidetes, Firmicutes and Cloroflexi showed that the bacterial communities were different. Species and genera of the Rhizobiales, Rhodobacterales and Xanthomonadales orders of the alpha- and gamma-subdivision of Proteobacteria were found at the three sites. Species and genera of the Rhodospirillales, Sphingobacteriales, Clostridiales, Oscillatoriales and Caldilineales were found only in the HIGH soil, Sphingomonadales, Burkholderiales and Pseudomonadales in the MEDIUM soil, Myxococcales in the LOW soil, and Actinomycetales in the MEDIUM and LOW soils. It was found that the largest diversity at the order and species level was found in the MEDIUM soil as bacteria of both the HIGH and LOW soils were found in it.

  13. Evolution of the fracture process zone in high-strength concrete under different loading rates

    Directory of Open Access Journals (Sweden)

    Cámara M.

    2010-06-01

    Full Text Available For cementitious materials, the inelastic zone around a crack tip is termed as fracture process zone (FPZ and dominated by complicated mechanism, such as microcracking, crack deflection, bridging, crack face friction, crack tip blunting by voids, crack branching, and so on. Due to the length of the FPZ is related with the characteristic length of the cementitious materials, the size, extent and location of the FPZ has been the object of countless research efforts for several decades. For instance, Cedolin et al. [1] have used an optical method based on the moiré interferometry to determine FPZ in concrete. Castro-Montero et al. [2] have applied the method of holographic interferometry to mortar to study the extension of the FPZ. The advantage of the interferometry method is that the complete FPZ can be directly observed on the surface of the sample. Swartz et al. [3] has adopted the dye penetration technique to illustrate the changing patterns observed as the crack progress from the tensile side to the compression side of the beam. Moreover, acoustic emission (AE is also an experimental technique well suited for monitoring fracture process. Haidar et al. [4] and Maji et al. [5] have studied the relation between acoustic emission characteristics and the properties of the FPZ. Compared with the extensive research on properties of the FPZ under quasi-static loading conditions, much less information is available on its dynamic characterization, especially for high-strength concrete (HSC. This paper presents the very recent results of an experimental program aimed at disclosing the loading rate effect on the size and velocity of the (FPZ in HSC. Eighteen three-point bending specimens were conducted under a wide range of loading rates from from 10-4 mm/s to 103 mm/s using either a servo-hydraulic machine or a self-designed drop-weight impact device. The beam dimensions were 100 mm 100 mm in cross section, and 420 mm in length. The initial notch

  14. Changes in performance and bacterial communities in response to various process disturbances in a high-rate biohydrogen reactor fed with galactose.

    Science.gov (United States)

    Park, Jeong-Hoon; Kumar, Gopalakrishnan; Park, Jong-Hun; Park, Hee-Deung; Kim, Sang-Hyoun

    2015-01-01

    High-rate biohydrogen production was achieved via hybrid immobilized cells fed with galactose in a continuous reactor system. The hybrid immobilized cells were broken down after 20 days and began to form granules by self-aggregation. The peak hydrogen production rate (HPR) and hydrogen yield (HY) of 11.8 ± 0.6 LH2/L-d and 2.1 ± 0.1 mol H2/molgalactose(added), respectively, were achieved at the hydraulic retention time (HRT) of 8h with an organic loading rate (OLR) of 45 g/L-d. This is the highest yet reported for the employment of galactose in a continuous system. Various process disturbances including shock loading, acidification, alkalization and starvation were examined through bacterial community analysis via pyrosequencing of the 16S rRNA genes. The proportion of Clostridia increased during the stable biohydrogen production periods, while that of Bacilli increased when the reactor was disturbed. However, due to the stability of the self-aggregated granules, the process performance was regained within 4-7 days.

  15. Analysis of ammonia-oxidizing bacteria dominating in lab-scale bioreactors with high ammonium bicarbonate loading

    NARCIS (Netherlands)

    Vejmelkova, D.; Sorokin, D.Y.; Abbas, B.; Kovaleva, O.L.; Kleerebezem, R.; Kampschreur, M.J.; Muyzer, G.; Van Loosdrecht, M.C.M.

    2011-01-01

    The ammonia-oxidizing bacterial community (AOB) was investigated in two types of laboratory-scale bioreactors performing partial oxidation of ammonia to nitrite or nitrate at high (80 mM) to extremely high (428 mM) concentrations of ammonium bicarbonate. At all conditions, the dominant AOB was affil

  16. Analysis of ammonia-oxidizing bacteria dominating in lab-scale bioreactors with high ammonium bicarbonate loading

    NARCIS (Netherlands)

    D. Vejmelkova; D.Y. Sorokin; B. Abbas; O.L. Kovaleva; R. Kleerebezem; M.J. Kampschreur; G. Muyzer; M.C.M. van Loosdrecht

    2012-01-01

    The ammonia-oxidizing bacterial community (AOB) was investigated in two types of laboratory-scale bioreactors performing partial oxidation of ammonia to nitrite or nitrate at high (80 mM) to extremely high (428 mM) concentrations of ammonium bicarbonate. At all conditions, the dominant AOB was affil

  17. Identification of Bacterial Pathogens in Ascitic Fluids from Patients with Suspected Spontaneous Bacterial Peritonitis by Use of Broad-Range PCR (16S PCR) Coupled with High-Resolution Melt Analysis

    OpenAIRE

    Hardick, Justin; Won, Helen; Jeng, Kevin; Hsieh, Yu-Hsiang; Gaydos, Charlotte A.; Richard E Rothman; Yang, Samuel

    2012-01-01

    Spontaneous bacterial peritonitis (SBP) can be a severe complication occurring in patients with cirrhosis and ascites, with associated mortality often as high as 40%. Traditional diagnostics for SBP rely on culture techniques for proper diagnosis, although recent reports suggest that the presence of bacterial DNA in peritoneal fluid in patients with cirrhosis and ascites is an indicator of SBP. A previously published broad-range PCR (16S PCR) coupled with high-resolution melt analysis (HRMA) ...

  18. Microwave-assisted synthesis of high-loading, highly dispersed Pt/carbon aerogel catalyst for direct methanol fuel cell

    Indian Academy of Sciences (India)

    Zhijun Guo; Hong Zhu; Xinwei Zhang; Fanghui Wang; Yubao Guo; Yongsheng Wei

    2011-06-01

    A Pt supported on carbon aerogel catalyst has been synthesized by the microwave-assisted polyol process. The Pt supported on carbon aerogel catalyst was characterized by high resolution transmission electron microscopy and X-ray diffraction. The results show a uniform dispersion of spherical Pt nanoparticles 2.5–3.0 nm in diameter. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity of the Pt/carbon aerogel catalyst for methanol oxidation at room temperature. The Pt/carbon aerogel catalyst shows higher electrochemical catalytic activity and stability for methanol oxidation than a commercial Pt/C catalyst of the same Pt loading.

  19. The Effect of Predeparture Training Loads on Posttour Physical Capacities in High-Performance Junior Tennis Players.

    Science.gov (United States)

    Murphy, Alistair P; Duffield, Rob; Kellett, Aaron; Gescheit, Dani; Reid, Machar

    2015-11-01

    Difficulties in preserving physical capacities while on tennis tours necessitate targeted training prescription. This study analyzed training and match loads performed before and on tour for their relationship with posttour physical-capacity changes. A secondary aim was to determine whether the presence of a strength and conditioning (S&C) coach affected the type and volume of on-tour training load. The training and match loads of 30 high-performance junior tennis players were recorded over 8 wk: 4 wk before and 4 wk during an international tour. Fitness tests were conducted pretour and posttour, including double and single-leg (dominant and nondominant) countermovement jump, speed (5, 10, and 20 m), modified 5-0-5 agility, 10 × 20-m repeated-sprint ability, and multistage fitness tests. Tour training and match loads were categorized according to whether S&C support was present or absent. Total and tennis training loads were significantly greater on tour than pretour (P ≤ .05, d > 0.8). Increases in on-tour, on-court training loads were moderately correlated with decrements in speed and aerobic power (r = .31-.52). Finally, S&C presence on tour significantly increased total, on-court, and off-court training load completed (P ≤ .05, d > 0.8). Training loads should be carefully prescribed to ensure that sufficient total and tennis loads are completed pretour. Specifically, speed and aerobic capacities may regress with increased training on tour. Finally, a practical observation was that on-tour S&C support resulted in increased S&C training load (around match loads), potentially countering the observed regression of physical capacities. Such a finding has the capacity to alter current physical-preparation structures in high-performance tennis environments with finite resources.

  20. Eradication of high viable loads of Listeria monocytogenes contaminating food-contact surfaces

    Directory of Open Access Journals (Sweden)

    Silvia ede Candia

    2015-07-01

    Full Text Available This study demonstrates the efficacy of cold gaseous ozone treatments at low concentrations in the eradication of high Listeria monocytogenes viable cell loads from glass, polypropylene, stainless steel and expanded polystyrene food-contact surfaces. Using a step by step approach, involving the selection of the most resistant strain-surface combinations, 11 Listeria spp. strains resulted inactivated by a continuous ozone flow at 1.07 mg m-3 after 24 or 48 h of cold incubation, depending on both strain and surface evaluated. Increasing the inoculum level to 9 log CFU coupon-1, the best inactivation rate was obtained after 48h of treatment at 3.21 mg m-3 ozone concentration when cells were deposited onto stainless steel and expanded polystyrene coupons, resulted the most resistant food-contact surfaces in the previous assays.The addition of naturally microbiologically contaminated meat extract to a high load of L. monocytogenes LMG 23775 cells, the most resistant strain out of the 11 assayed Listeria spp. strains, led to its complete inactivation after four days of treatment.To the best of our knowledge, this is the first report describing the survival of L. monocytogenes and the effect of ozone treatment under cold storage conditions on expanded polystyrene, a commonly-used material in food packaging. These results could be useful for reducing pathogen cross-contamination phenomena during cold food storage.

  1. Core-shell nanocarriers with high paclitaxel loading for passive and active targeting

    Science.gov (United States)

    Jin, Zhu; Lv, Yaqi; Cao, Hui; Yao, Jing; Zhou, Jianping; He, Wei; Yin, Lifang

    2016-06-01

    Rapid blood clearance and premature burst release are inherent drawbacks of conventional nanoparticles, resulting in poor tumor selectivity. iRGD peptide is widely recognized as an efficient cell membrane penetration peptide homing to αVβ3 integrins. Herein, core-shell nanocapsules (NCs) and iRGD-modified NCs (iRGD-NCs) with high drug payload for paclitaxel (PTX) were prepared to enhance the antitumor activities of chemotherapy agents with poor water solubility. Improved in vitro and in vivo tumor targeting and penetration were observed with NCs and iRGD-NCs; the latter exhibited better antitumor activity because iRGD enhanced the accumulation and penetration of NCs in tumors. The NCs were cytocompatible, histocompatible, and non-toxic to other healthy tissues. The endocytosis of NCs was mediated by lipid rafts in an energy-dependent manner, leading to better cytotoxicity of PTX against cancer cells. In contrast with commercial product, PTX-loaded NCs (PTX-NCs) increased area under concentration-time curve (AUC) by about 4-fold, prolonged mean resident time (MRT) by more than 8-fold and reduced the elimination rate constant by greater than 68-fold. In conclusion, the present nanocarriers with high drug-loading capacity represent an efficient tumor-targeting drug delivery system with promising potential for cancer therapy.

  2. High organic loading treatment for industrial molasses wastewater and microbial community shifts corresponding to system development.

    Science.gov (United States)

    Kuroda, Kyohei; Chosei, Tomoaki; Nakahara, Nozomi; Hatamoto, Masashi; Wakabayashi, Takashi; Kawai, Toshikazu; Araki, Nobuo; Syutsubo, Kazuaki; Yamaguchi, Takashi

    2015-11-01

    Molasses wastewater contains high levels of organic compounds, cations, and anions, causing operational problems for anaerobic biological treatment. To establish a high organic loading treatment system for industrial molasses wastewater, this study designed a combined system comprising an acidification tank, a thermophilic multi-stage (MS)-upflow anaerobic sludge blanket (UASB) reactor, mesophilic UASB reactor, and down-flow hanging sponge reactor. The average total chemical oxygen demand (COD) and biochemical oxygen demand removal rates were 85%±3% and 95%±2%, respectively, at an organic loading rate of 42kgCODcrm(-3)d(-1) in the MS-UASB reactor. By installation of the acidification tank, the MS-UASB reactor achieved low H2-partial pressure. The abundance of syntrophs such as fatty acid-degrading bacteria increased in the MS-UASB and 2nd-UASB reactors. Thus, the acidification tank contributed to maintaining a favorable environment for syntrophic associations. This study provides new information regarding microbial community composition in a molasses wastewater treatment system. Copyright © 2015. Published by Elsevier Ltd.

  3. A high-power switch-mode dc power supply for dynamic loads

    Energy Technology Data Exchange (ETDEWEB)

    Shimer, D.W.; Lange, A.C. [Lawrence Livermore National Lab., CA (United States); Bombay, J.N. [Kaiser Engineers, Oakland, CA (United States)

    1994-06-23

    High-voltage dc power supplies are often required to operate with highly dynamic loads, such as arcs. A switch-mode dc power supply can offer significant advantages over conventional thyristor-based dc power supplies under such conditions. It can quickly turn off the supply to extinguish the arc, and it can quickly recover after the arc. It has a relatively small output filter capacitance, which results in small stored energy available to the arc. A 400-kW, 50-kV switch-mode dc power supply for an electron-beam gun that exploits these advantages was designed and tested. It uses four 100-kW, current-source-type dc-dc converters with inputs in parallel and outputs in series. The dc-dc converters operate at 20 kHz in the voltage regulator part and 10 kHz in the inverter, transformer, and output rectifier part of the circuit. Insulated gate bipolar transistors (IGBTs) are used as the power switches. Special techniques are used to protect the power supply and load against arcs and hard shorts. The power supply has an efficiency of 93%, an output voltage ripple of 1%, and fast dynamic response. In addition, it is nearly one-third the size of conventional power supplies.

  4. The role of superconductivity in magnetic bearings for high-load applications

    Science.gov (United States)

    Downer, James; Eisenhaure, David

    1993-01-01

    Slewing of large payloads will require control torque and angular momentum storage capacities that are large in comparison to the capabilities of available control moment gyros (CMG's). SatCon Technology Corporation is currently designing a CMG which may be employed as a slew actuator for large spacecraft or other payloads. The slew actuator employs a type of magnetic bearing which may be used in high load applications. The magnetic bearing is also used to fully gimbal the suspended rotor of the slew actuator. The use of magnetic bearings in angular momentum exchange actuators has the primary advantage that physical contact between the rotor and stator is eliminated. This leads to greatly extended life, increased reliability, and reduced vibrations. Several actuators operating on magnetic bearings have been demonstrated in previous research efforts. These were sized for use in small satellites. For conventional magnetic bearings, which employ magnetic cores, high torsional loading may require that the magnetic structure be excessively massive. An alternative magnetic bearing design which employs a superconducting coil and eliminates conventional magnetic structures is discussed. The baseline approach is to replace the field coil of a conventional magnetic bearing with the superconducting coil.

  5. Carbon, metals and grain size correlate with bacterial community composition in sediments of a high arsenic aquifer

    Directory of Open Access Journals (Sweden)

    Teresa eLegg

    2012-03-01

    Full Text Available Bacterial communities can exert significant influence on the biogeochemical cycling of arsenic (As. This has globally important implications since As toxicity in drinking water affects the health of millions of people worldwide, including in the Ganges-Brahmaputra Delta region of Bangladesh where geogenic groundwater arsenic concentrations can be more than 10 times the World Health Organization’s limit. Thus, the goal of this research was to investigate patterns in bacterial community composition across environmental gradients in an aquifer with elevated groundwater As concentrations in Araihazar, Bangladesh. We characterized the bacterial community by pyrosequencing 16S rRNA genes from aquifer sediment samples collected at three locations along a groundwater flowpath, at a range of depths between 1.5 and 15 m. We identified significant shifts in bacterial community composition along the groundwater flowpath in the aquifer. In addition, we found that bacterial community structure was significantly related to sediment grain size, and sediment carbon (C, manganese (Mn, and iron (Fe concentrations. Deltaproteobacteria and Chloroflexi were more abundant in silty sediments with higher concentrations of C, Fe, and Mn. By contrast, Alphaproteobacteria and Betaproteobacteria were more abundant in sediments with higher concentrations of sand and Si, and lower concentrations of C and metals. Based on the phylogenetic affiliations of these taxa, these results may indicate a shift to more Fe-, Mn-, and humic substance- reducers in the high C and metal sediments. It is well-documented that C, Mn and Fe may influence the mobility of groundwater arsenic, and it is intriguing that these constituents may also structure the bacterial community.

  6. Hybrid Robust Control Law with Disturbance Observer for High-Frequency Response Electro-Hydraulic Servo Loading System

    Directory of Open Access Journals (Sweden)

    Zhiqing Sheng

    2016-04-01

    Full Text Available Addressing the simulating issue of the helicopter-manipulating booster aerodynamic load with high-frequency dynamic load superimposed on a large static load, this paper studies the design of the robust controller for the electro-hydraulic loading system to realize the simulation of this kind of load. Firstly, the equivalent linear model of the electro-hydraulic loading system under assumed parameter uncertainty is established. Then, a hybrid control scheme is proposed for the loading system. This control scheme consists of a constant velocity feed-forward compensator, a robust inner loop compensator based on disturbance observer and a robust outer loop feedback controller. The constant velocity compensator eliminates most of the extraneous force at first, and then the double-loop cascade composition control strategy is employed to design the compensated system. The disturbance observer–based inner loop compensator further restrains the disturbances including the remaining extraneous force, and makes the actual plant tracking a nominal model approximately in a certain frequency range. The robust outer loop controller achieves the desired force-tracking performance, and guarantees system robustness in the high frequency region. The optimized low-pass filter Q(s is designed by using the H∞ mixed sensitivity optimization method. The simulation results show that the proposed hybrid control scheme and controller can effectively suppress the extraneous force and improve the robustness of the electro-hydraulic loading system.

  7. Bacteria in the injection water differently impacts the bacterial communities of production wells in high-temperature petroleum reservoirs

    Directory of Open Access Journals (Sweden)

    Hongyan eRen

    2015-05-01

    Full Text Available Water flooding is widely used for oil recovery. However, how the introduction of bacteria via water flooding affects the subsurface ecosystem remains unknown. In the present study, the distinct bacterial communities of an injection well and 6 adjacent production wells were revealed using denaturing gradient gel electrophoresis (DGGE and pyrosequencing. All sequences of the variable region 3 of the 16S rRNA gene retrieved from pyrosequencing were divided into 543 operational taxonomic units (OTUs based on 97% similarity. Approximately 13.5% of the total sequences could not be assigned to any recognized phylum. The Unifrac distance analysis showed significant differences in the bacterial community structures between the production well and injection water samples. However, highly similar bacterial structures were shown for samples obtained from the same oil-bearing strata. More than 69% of the OTUs detected in the injection water sample were absent or detected in low abundance in the production wells. However, the abundance of two OTUs reached as high as 17.5% and 26.9% in two samples of production water, although the OTUs greatly varied among all samples. Combined with the differentiated water flow rate measured through ion tracing, we speculated that the transportation of injected bacteria was impacted through the varied permeability from the injection well to each of the production wells. Whether the injected bacteria predominate the production well bacterial community might depend both on the permeability of the strata and the reservoir conditions.

  8. Correlation of bacterial vaginosis with preterm labour: a case control study

    Directory of Open Access Journals (Sweden)

    Waseeqa Nigeen

    2015-12-01

    Conclusions: Bacterial vaginosis is significantly more prevalent in women with preterm labour. Whiff test can be used alone in centres where the patient load is too high. Illiteracy is a risk factor that can be modified to bring down incidence of bacterial vaginosis. [Int J Reprod Contracept Obstet Gynecol 2015; 4(6.000: 1868-1874

  9. Gluconacetobacter hansenii subsp. nov., a high-yield bacterial cellulose producing strain induced by high hydrostatic pressure.

    Science.gov (United States)

    Ge, Han-Jing; Du, Shuang-Kui; Lin, De-Hui; Zhang, Jun-Na; Xiang, Jin-Le; Li, Zhi-Xi

    2011-12-01

    Strain M(438), deposited as CGMCC3917 and isolated from inoculums of bacterial cellulose (BC) producing strain screened in homemade vinegar and then induced by high hydrostatic pressure treatment (HHP), has strong ability to produce BC more than three times as that of its initial strain. It is the highest yield BC-producing strain ever reported. In this paper, M(438) was identidied as Gluconacetobacter hansenii subsp. nov. on the basis of the results obtained by examining it phylogenetically, phenotypically, and physiologically-biochemically. Furthermore, the genetic diversity of strain M(438) and its initial strain was examined by amplified fragment length polymorphism. The results indicated that strain M(438) was a deletion mutant induced by HHP, and the only deleted sequence showed 99% identity with 24,917-24,723 bp in the genome sequence of Ga. hansenii ATCC23769, and the complement gene sequence was at 24,699-25,019 bp with local tag GXY_15142, which codes small multidrug resistance (SMR) protein. It can be inferred that SMR might be related to inhibiting BC production to a certain extent.

  10. An ultra-high temperature flow-through capillary device for bacterial spore lysis.

    Science.gov (United States)

    Hukari, Kyle W; Patel, Kamlesh D; Renzi, Ronald F; West, Jay A A

    2010-08-01

    Rapid and specific characterization of bacterial endospores is dependent on the ability to rupture the cell wall to enable analysis of the intracellular components. In particular, bacterial spores from the bacillus genus are inherently robust and very difficult to lyze or solubilize. Standard protocols for spore inactivation include chemical treatment, sonication, pressure, and thermal lysis. Although these protocols are effective for the inactivation of these agents, they are less well suited for sample preparation for analysis using proteomic and genomic approaches. To overcome this difficulty, we have designed a simple capillary device to perform thermal lysis of bacterial spores. Using this device, we were able to super heat (195 degrees C) an ethylene glycol lysis buffer to perform rapid flow-through rupture and solubilization of bacterial endospores. We demonstrated that the lysates from this preparation method are compatible with CGE as well as DNA amplification analysis. We further demonstrated the flow-through lysing device could be directly coupled to a miniaturized electrophoresis instrument for integrated sample preparation and analysis. In this arrangement, we were enabled to perform sample lysis, fluorescent dye labeling, and protein electrophoresis analysis of bacterial spores in less than 10 min. The described sample preparation device is rapid, simple, inexpensive, and easily integratable with various microfluidic devices.

  11. A highly precise and portable genome engineering method allows comparison of mutational effects across bacterial species.

    Science.gov (United States)

    Nyerges, Ákos; Csörgő, Bálint; Nagy, István; Bálint, Balázs; Bihari, Péter; Lázár, Viktória; Apjok, Gábor; Umenhoffer, Kinga; Bogos, Balázs; Pósfai, György; Pál, Csaba

    2016-03-01

    Currently available tools for multiplex bacterial genome engineering are optimized for a few laboratory model strains, demand extensive prior modification of the host strain, and lead to the accumulation of numerous off-target modifications. Building on prior development of multiplex automated genome engineering (MAGE), our work addresses these problems in a single framework. Using a dominant-negative mutant protein of the methyl-directed mismatch repair (MMR) system, we achieved a transient suppression of DNA repair in Escherichia coli, which is necessary for efficient oligonucleotide integration. By integrating all necessary components into a broad-host vector, we developed a new workflow we term pORTMAGE. It allows efficient modification of multiple loci, without any observable off-target mutagenesis and prior modification of the host genome. Because of the conserved nature of the bacterial MMR system, pORTMAGE simultaneously allows genome editing and mutant library generation in other biotechnologically and clinically relevant bacterial species. Finally, we applied pORTMAGE to study a set of antibiotic resistance-conferring mutations in Salmonella enterica and E. coli. Despite over 100 million y of divergence between the two species, mutational effects remained generally conserved. In sum, a single transformation of a pORTMAGE plasmid allows bacterial species of interest to become an efficient host for genome engineering. These advances pave the way toward biotechnological and therapeutic applications. Finally, pORTMAGE allows systematic comparison of mutational effects and epistasis across a wide range of bacterial species.

  12. Rapid room temperature solubilization and depolymerization of polymeric lignin at high loadings

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jian; Dutta, Tanmoy; Parthasarathi, Ramakrishnan; Kim, Kwang Ho; Tolic, Nikola; Chu, Rosalie K.; Isern, Nancy G.; Cort, John R.; Simmons, Blake A.; Singh, Seema

    2016-10-03

    The relatively poor solubility of lignin in most pretreatment solvents remains one of the biggest challegnes in lignin valorization to improve overall biorefinery economics. In this work, rapid room temperature solubilization of lignin at high solid loadings (>30 wt%) can be easily achieved in a single step using ethylene glycol (EG). The solubilized lignin can be rapidly and quantitively recovered with the addtion of ethanol. The computational and nuclear magnetic resonance (NMR) spectroscopic studies confirm that strong hydrogen bond interactions between EG and the free hydroxyl groups present in lignin contribute to the lignin dissolution. In addition, hydrogen peroxide mediated depolymerization of dissolved lignin at low temperature (80 oC) was tested and the effect of EG molecules on depolymerization of ligin was also theoritically studied. The findings of this work provide mechanistic insights of hydrogen bond interactions in high lignin solubilization and valorization.

  13. Application of high-resolution domestic electricity load profiles in network modelling

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna; Mendaza, Iker Diaz de Cerio; Heiselberg, Per Kvols

    2016-01-01

    % of buildings, the loading of the transformer and power lines is reduced in the summer time to 58% and 51%, respectively. However, the power lines are stress with bi-directional power flow. The results indicate that the business-as-usual approach to network modeling is not sufficient to capture......The ongoing development towards electrification of the energy consumption together with large deployment of renewable energy sources creates new challenges of variability and fluctuation of the electricity supply and increases complexity of the network operation. In order to capture all...... the particularities of electricity demand and on-site generation, e.g. the short-term spikes due use of high electricity consumption appliances such like electric kettle, and get a full picture of network performance, a high-resolution input data are needed. This paper compares the business-as-usual network modeling...

  14. Estimated environmental loads of alpha-amylase from transgenic high-amylase maize

    Energy Technology Data Exchange (ETDEWEB)

    Wolt, Jeffrey D. [Department of Agronomy, Iowa State University, Ames, IA 50011 (United States); Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States); Karaman, Sule [Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States)

    2007-11-15

    Environmental exposure of plants bioengineered to improve efficiencies of biofuel production is an important consideration for their adoption. High-amylase maize genetically engineered to produce thermostable alpha-amylase in seed endosperm is currently in development, and its successful adoption will entail >1000 km{sup 2} of annual production in the USA. Environmental exposure of thermostable amylase will occur in production fields from preharvest and harvest dropped grain, with minor additional contributions from stover and root biomass. Mass loadings of thermostable alpha-amylase are projected to be 16 kg km{sup -2} and represent a potential source of increased alpha-amylase activity in receiving soils. An understanding of the degradation, persistence, accumulation, and activity of thermostable alpha-amylase introduced from transgenic high-amylase maize will be necessary in order to effectively manage transgenic crop systems intended or biofeedstock production. (author)

  15. The cryogenic cooling program in high-heat-load optics at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, C.S.

    1993-07-01

    This paper describes some of the aspects of the cryogenic optics program at the Advanced Photon Source (APS). A liquid-nitrogen-cooled, high-vacuum, double crystal monochromator is being fabricated at Argonne National Laboratory (ANL). A pumping system capable of delivering a variable flow rate of up to 10 gallons per minute of pressurized liquid nitrogen and removing 5 kilowatts of x-ray power is also being constructed. This specialized pumping system and monochromator will be used to test the viability of cryogenically cooled, high-heat-load synchrotron optics. It has been determined that heat transfer enhancement will be required for optics used with APS insertion devices. An analysis of a porous-matrix-enhanced monochromator crystal is presented. For the particular case investigated, a heat transfer enhancement factor of 5 to 6 was calculated.

  16. Cost optimization of load carrying thin-walled precast high performance concrete sandwich panels

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hansen, Sanne; Hulin, Thomas

    2015-01-01

    and HPCSP’s geometrical parameters as well as on material cost function in the HPCSP design. Cost functions are presented for High Performance Concrete (HPC), insulation layer, reinforcement and include labour-related costs. The present study reports the economic data corresponding to specific manufacturing......The paper describes a procedure to find the structurally and thermally efficient design of load-carrying thin-walled precast High Performance Concrete Sandwich Panels (HPCSP) with an optimal economical solution. A systematic optimization approach is based on the selection of material’s performances....... The solution of the optimization problem is performed in the computer package software Matlab® with SQPlab package and integrates the processes of HPCSP design, quantity take-off and cost estimation. The proposed optimization process outcomes in complex HPCSP design proposals to achieve minimum cost of HPCSP....

  17. Load management strategy for Particle-In-Cell simulations in high energy physics

    CERN Document Server

    Beck, Arnaud; Derouillat, Julien

    2015-01-01

    In the wake of the intense effort made for the experimental CILEX project, numerical simulation campaigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. By comparing the results given by different codes, it is possible to point out algorithmic limitations both in terms of physical accuracy and computational performances. In this paper we illustrate some of these limitations in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-performance PIC code for high energy physics.

  18. Load management strategy for Particle-In-Cell simulations in high energy particle acceleration

    Science.gov (United States)

    Beck, A.; Frederiksen, J. T.; Dérouillat, J.

    2016-09-01

    In the wake of the intense effort made for the experimental CILEX project, numerical simulation campaigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. In this paper, we compare the results given by different codes and point out algorithmic limitations both in terms of physical accuracy and computational performances. These limitations are illustrated in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-performance PIC code for high energy particle acceleration.

  19. Turbulence Resolving Flow Simulations of a Francis Turbine in Part Load using Highly Parallel CFD Simulations

    Science.gov (United States)

    Krappel, Timo; Riedelbauch, Stefan; Jester-Zuerker, Roland; Jung, Alexander; Flurl, Benedikt; Unger, Friedeman; Galpin, Paul

    2016-11-01

    The operation of Francis turbines in part load conditions causes high fluctuations and dynamic loads in the turbine and especially in the draft tube. At the hub of the runner outlet a rotating vortex rope within a low pressure zone arises and propagates into the draft tube cone. The investigated part load operating point is at about 72% discharge of best efficiency. To reduce the possible influence of boundary conditions on the solution, a flow simulation of a complete Francis turbine is conducted consisting of spiral case, stay and guide vanes, runner and draft tube. As the flow has a strong swirling component for the chosen operating point, it is very challenging to accurately predict the flow and in particular the flow losses in the diffusor. The goal of this study is to reach significantly better numerical prediction of this flow type. This is achieved by an improved resolution of small turbulent structures. Therefore, the Scale Adaptive Simulation SAS-SST turbulence model - a scale resolving turbulence model - is applied and compared to the widely used RANS-SST turbulence model. The largest mesh contains 300 million elements, which achieves LES-like resolution throughout much of the computational domain. The simulations are evaluated in terms of the hydraulic losses in the machine, evaluation of the velocity field, pressure oscillations in the draft tube and visual comparisons of turbulent flow structures. A pre-release version of ANSYS CFX 17.0 is used in this paper, as this CFD solver has a parallel performance up to several thousands of cores for this application which includes a transient rotor-stator interface to support the relative motion between the runner and the stationary portions of the water turbine.

  20. Influence of high glycemic index and glycemic load diets on blood pressure during adolescence.

    Science.gov (United States)

    Gopinath, Bamini; Flood, Victoria M; Rochtchina, Elena; Baur, Louise A; Smith, Wayne; Mitchell, Paul

    2012-06-01

    We aimed to prospectively examine the association between the glycemic index and glycemic load of foods consumed and the dietary intakes of carbohydrates, sugars, fiber, and principal carbohydrate-containing food groups (eg, breads, cereals, and sugary drinks) with changes in blood pressure during adolescence. A total of 858 students aged 12 years at baseline (422 girls and 436 boys) were examined from 2004-2005 to 2009-2011. Dietary data were assessed from validated semiquantitative food frequency questionnaires. Blood pressure was measured using a standard protocol. In girls, after adjusting for age, ethnicity, parental education, parental history of hypertension, baseline height, baseline blood pressure, change in body mass index, and time spent in physical and sedentary activities, each 1-SD (1-SD = 7.10 g/d) increase in baseline dietary intake of total fiber was associated with a 0.96-, 0.62-, and 0.75-mmHg decrease in mean systolic (P = 0.02), diastolic (P = 0.01), and arterial blood pressures (P = 0.002), respectively, 5 years later. In girls, each 1-SD increase in dietary glycemic index, glycemic load, carbohydrate, and fructose was concurrently related to increases of 1.81 (P = 0.001), 4.02 (P = 0.01), 4.74 (P = 0.01), and 1.80 mm Hg (P = 0.03) in systolic blood pressure, respectively, >5 years. Significant associations between carbohydrate nutrition variables and blood pressure were not observed among boys. Excessive dietary intake of carbohydrates, specifically from high glycemic index/glycemic load foods, could adversely influence blood pressure, particularly in girls, whereas fiber-rich diets may be protective against elevated blood pressure during adolescence.

  1. The effects of varying resistance-training loads on intermediate- and high-velocity-specific adaptations.

    Science.gov (United States)

    Jones, K; Bishop, P; Hunter, G; Fleisig, G

    2001-08-01

    The purpose of this study was to compare changes in velocity-specific adaptations in moderately resistance-trained athletes who trained with either low or high resistances. The study used tests of sport-specific skills across an intermediate- to high-velocity spectrum. Thirty NCAA Division I baseball players were randomly assigned to either a low-resistance (40-60% 1 repetition maximum [1RM]) training group or a high-resistance (70-90% 1RM) training group. Both of the training groups intended to maximallv accelerate each repetition during the concentric phase (IMCA). The 10 weeks of training consisted of 4 training sessions a week using basic core exercises. Peak force, velocity, and power were evaluated during set angle and depth jumps as well as weighted jumps using 30 and 50% 1RM. Squat 1RMs were also tested. Although no interactions for any of the jump tests were found, trends supported the hypothesis of velocity-specific training. Percentage gains suggest that the combined use of heavier training loads (70-90% 1RM) and IMCA tend to increase peak force in the lower-body leg and hip extensors. Trends also show that the combined use of lighter training loads (40-60% 1RM) and IMCA tend to increase peak power and peak velocity in the lower-body leg and hip extensors. The high-resistance group improved squats more than the low-resistance group (p IMCA to increase 1RM strength in the lower bodies of resistance-trained athletes.

  2. Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

    2010-01-01

    In a previous study, vane-rotor shock interactions and heat transfer on the rotor blade of a highly loaded transonic turbine stage were simulated. The geometry consists of a high pressure turbine vane and downstream rotor blade. This study focuses on the physics of flow and heat transfer in the rotor tip, casing and hub regions. The simulation was performed using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) code MSU-TURBO. A low Reynolds number k-epsilon model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1 percent of the blade height. The Reynolds number of the flow is approximately 3x10(exp 6) per meter. Unsteadiness was observed at the tip surface that results in intermittent "hot spots". It is demonstrated that unsteadiness in the tip gap is governed by inviscid effects due to high speed flow and is not strongly dependent on pressure ratio across the tip gap contrary to published observations that have primarily dealt with subsonic tip flows. The high relative Mach numbers in the tip gap lead to a choking of the leakage flow that translates to a relative attenuation of losses at higher loading. The efficacy of new tip geometry is discussed to minimize heat flux at the tip while maintaining choked conditions. In addition, an explanation is provided that shows the mechanism behind the rise in stagnation temperature on the casing to values above the absolute total temperature at the inlet. It is concluded that even in steady mode, work transfer to the near tip fluid occurs due to relative shearing by the casing. This is believed to be the first such explanation of the work transfer phenomenon in the open literature. The difference in pattern between steady and time-averaged heat flux at the hub is also explained.

  3. Polyamidoamine dendrimer-based binders for high-loading lithium–sulfur battery cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Priyanka; Nandasiri, Manjula I.; Lv, Dongping; Schwarz, Ashleigh M.; Darsell, Jens T.; Henderson, Wesley A.; Tomalia, Donald A.; Liu, Jun; Zhang, Ji-Guang; Xiao, Jie

    2016-01-01

    Lithium-sulfur (Li-S) batteries are regarded as one of the most promising candidates for next generation energy storage systems because of their ultra high theoretical specific energy. To realize the practical application of Li-S batteries, however, a high S active material loading is essential (>70 wt% in the carbon-sulfur (C-S) composite cathode and >2 mg cm-2 in the electrode). A critical challenge to achieving this high capacity in practical electrodes is the dissolution of the longer lithium polysulfide reaction intermediates in the electrolyte (resulting in loss of active material from the cathode and contamination of the anode due to the polysulfide shuttle mechanism). The binder material used for the cathode is therefore crucial as this is a key determinant of the bonding interactions between the active material (S) and electronic conducting support (C), as well as the maintenance of intimate contact between the electrode materials and current collector. The battery performance can thus be directly correlated with the choice of binder, but this has received only minimal attention in the relevant Li-S battery published literature. Here, we investigated the application of polyamidoamine (PAMAM) dendrimers as functional binders in Li-S batteries—a class of materials which has been unexplored for electrode design. By using dendrimers, it is demonstrated that high S loadings (>4 mg cm-2) can be easily achieved using "standard" (not specifically tailored) materials and simple processing methods. An exceptional electrochemical cycling performance was obtained (as compared to cathodes with conventional linear polymeric binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR)) with >100 cycles and 85-98% capacity retention, thus demonstrating the significant utility of this new binder architecture which exhibits critical physicochemical properties and flexible nanoscale design parameters (CNDP's).

  4. High Pt Loading on Polydopamine Functionalized Graphene as a High Performance Cathode Electrocatalyst for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Monireh Faraji

    2016-04-01

    Full Text Available Morphology and size of platinum nanoparticles are a crucial factor in improving their catalytic activity and stability. Here, we firstly report the synthesis of high loading Pt nanoparticles on polydopamine reduced Graphene. The loading concentration of Pt (nanoparticles NPs on Graphene can be adjusted in the range of 60-70%.With the insertion of polydopamine between Graphene oxide sheets, stacking of Graphene can be effectively prevented, promoting diffusion of oxygen molecules through the Graphene sheets and enhancing the oxygen reduction reaction electrocatalytic activity. Compared to commercial catalysts (i.e., state-of-the-art Pt/C catalyst the as synthesized Pt supported polydopamine grafted reduced graphite oxide (Pt@PDA-rGO hybrid displays very high oxygen reduction reaction catalytic activities. We propose a unique 2D profile of the polydopamine-rGO role as a barrier preventing leaching of Pt into the electrolyte. The fabricated electrodes were evaluated with electrochemical techniques for oxygen reduction reaction and the obtained results were further verified by the transmission electron microscopy micrographs on the microstructure of the integrated pt@PDA-rGO structures. It has been revealed that the electrochemical impedance spectroscopy technique can provide more explicit information than polarization curves on the performance dependence on charge-transfer and mass transport processes at different overpotential regions.

  5. High-Speed "4D" Computational Microscopy of Bacterial Surface Motility.

    Science.gov (United States)

    de Anda, Jaime; Lee, Ernest Y; Lee, Calvin K; Bennett, Rachel R; Ji, Xiang; Soltani, Soheil; Harrison, Mark C; Baker, Amy E; Luo, Yun; Chou, Tom; O'Toole, George A; Armani, Andrea M; Golestanian, Ramin; Wong, Gerard C L

    2017-09-26

    Bacteria exhibit surface motility modes that play pivotal roles in early-stage biofilm community development, such as type IV pili-driven "twitching" motility and flagellum-driven "spinning" and "swarming" motility. Appendage-driven motility is controlled by molecular motors, and analysis of surface motility behavior is complicated by its inherently 3D nature, the speed of which is too fast for confocal microscopy to capture. Here, we combine electromagnetic field computation and statistical image analysis to generate 3D movies close to a surface at 5 ms time resolution using conventional inverted microscopes. We treat each bacterial cell as a spherocylindrical lens and use finite element modeling to solve Maxwell's equations and compute the diffracted light intensities associated with different angular orientations of the bacterium relative to the surface. By performing cross-correlation calculations between measured 2D microscopy images and a library of computed light intensities, we demonstrate that near-surface 3D movies of Pseudomonas aeruginosa translational and rotational motion are possible at high temporal resolution. Comparison between computational reconstructions and detailed hydrodynamic calculations reveals that P. aeruginosa act like low Reynolds number spinning tops with unstable orbits, driven by a flagellum motor with a torque output of ∼2 pN μm. Interestingly, our analysis reveals that P. aeruginosa can undergo complex flagellum-driven dynamical behavior, including precession, nutation, and an unexpected taxonomy of surface motility mechanisms, including upright-spinning bacteria that diffuse laterally across the surface, and horizontal bacteria that follow helicoidal trajectories and exhibit superdiffusive movements parallel to the surface.

  6. Preparation of HCPT-Loaded Nanoneedles with Pointed Ends for Highly Efficient Cancer Chemotherapy

    Science.gov (United States)

    Wu, Shichao; Yang, Xiangrui; Li, Yang; Wu, Hongjie; Huang, Yu; Xie, Liya; Zhang, Ying; Hou, Zhenqing; Liu, Xiangyang

    2016-06-01

    The high-aspect-ratio nanoparticles were proved to be internalized much more rapidly and efficiently by cancer cells than the nanoparticles with an equal aspect ratio. Herein, a kind of high-aspect ratio, pointed-end nanoneedles (NDs) with a high drug loading (15.04 %) and the prolonged drug release profile were fabricated with an anti-tumor drug—10-hydroxycamptothecin (HCPT)—via an ultrasound-assisted emulsion crystallization technique. It is surprising to see that the cellular internalization of NDs with an average length of 5 μm and an aspect ratio of about 12:1 was even much faster and higher than that of nanorods with the same size and the nanospheres with a much smaller size of 150 nm. The results further validated that cellular internalization of the nanoparticles exhibited a strong shape-dependent effect, and cellular uptake may favor the particles with sharp ends as well as a high-aspect ratio instead of particle size. The NDs with enhanced cytotoxicity would lead to a promising sustained local drug delivery system for highly efficient anticancer therapy. More importantly, the fabrication of NDs opens a door to design new formulations of nanoneedle drug delivery systems for highly efficient cancer.

  7. ITER-W monoblocks under high pulse number transient heat loads at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Loewenhoff, Th., E-mail: T.Loewenhoff@fz-juelich.de [Forschungszentrum Jülich, 52428 Jülich (Germany); Linke, J., E-mail: J.Linke@fz-juelich.de [Forschungszentrum Jülich, 52428 Jülich (Germany); Pintsuk, G., E-mail: G.Pintsuk@fz-juelich.de [Forschungszentrum Jülich, 52428 Jülich (Germany); Pitts, R.A., E-mail: Richard.Pitts@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-Lez-Durance (France); Riccardi, B., E-mail: Bruno.Riccardi@f4e.europa.eu [Fusion for Energy Joint Undertaking, Josep Pla No. 2 – T B3 7/01, Barcelona 08019 (Spain)

    2015-08-15

    In the context of using a full-tungsten (W) divertor for ITER, thermal shock resistance has become even more important as an issue that may potentially influence the long term performance. To address this issue a unique series of experiments has been performed on ITER-W monoblock mock ups in three EU high heat flux facilities: GLADIS (neutral beam), JUDITH 2 (electron beam) and Magnum-PSI (plasma beam). This paper discusses the JUDITH 2 experiments. Two different base temperatures, 1200 °C and 1500 °C, were chosen superimposed by ∼18,000/100,000 transient events (Δt = 0.48 ms) of 0.2 and 0.6 GW/m{sup 2}. Results showed a stronger surface deterioration at higher base temperature, quantified by an increase in roughening. This is intensified if the same test is done after preloading (exposure to high temperature without transients), especially at higher base temperature when the material recrystallizes.

  8. An integrated flow cytometry-based system for real-time, high sensitivity bacterial detection and identification.

    Directory of Open Access Journals (Sweden)

    Dan A Buzatu

    Full Text Available Foodborne illnesses occur in both industrialized and developing countries, and may be increasing due to rapidly evolving food production practices. Yet some primary tools used to assess food safety are decades, if not centuries, old. To improve the time to result for food safety assessment a sensitive flow cytometer based system to detect microbial contamination was developed. By eliminating background fluorescence and improving signal to noise the assays accurately measure bacterial load or specifically identify pathogens. These assays provide results in minutes or, if sensitivity to one cell in a complex matrix is required, after several hours enrichment. Conventional assessments of food safety require 48 to 56 hours. The assays described within are linear over 5 orders of magnitude with results identical to culture plates, and report live and dead microorganisms. This system offers a powerful approach to real-time assessment of food safety, useful for industry self-monitoring and regulatory inspection.

  9. Amelioration of high salinity stress damage by plant growth-promoting bacterial endophytes that contain ACC deaminase.

    Science.gov (United States)

    Ali, Shimaila; Charles, Trevor C; Glick, Bernard R

    2014-07-01

    Plant growth and productivity is negatively affected by soil salinity. However, it is predicted that plant growth-promoting bacterial (PGPB) endophytes that contain 1-aminocyclopropane-1-carboxylate (ACC) deaminase (E.C. 4.1.99.4) can facilitate plant growth and development in the presence of a number of different stresses. In present study, the ability of ACC deaminase containing PGPB endophytes Pseudomonas fluorescens YsS6, Pseudomonas migulae 8R6, and their ACC deaminase deficient mutants to promote tomato plant growth in the absence of salt and under two different levels of salt stress (165 mM and 185 mM) was assessed. It was evidence that wild-type bacterial endophytes (P. fluorescens YsS6 and P. migulae 8R6) promoted tomato plant growth significantly even in the absence of stress (salinity). Plants pretreated with wild-type ACC deaminase containing endophytic strains were healthier and grew to a much larger size under high salinity stress compared to plants pretreated with the ACC deaminase deficient mutants or no bacterial treatment (control). The plants pretreated with ACC deaminase containing bacterial endophytes exhibit higher fresh and dry biomass, higher chlorophyll contents, and a greater number of flowers and buds than the other treatments. Since the only difference between wild-type and mutant bacterial endophytes was ACC deaminase activity, it is concluded that this enzyme is directly responsible for the different behavior of tomato plants in response to salt stress. The use of PGPB endophytes with ACC deaminase activity has the potential to facilitate plant growth on land that is not normally suitable for the majority of crops due to their high salt contents.

  10. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy

    DEFF Research Database (Denmark)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H.

    2017-01-01

    . This is followed by automated microscopy and subsequent semi-automated spot detection to determine the number of intracellular bacterial colonies, their size distribution, and the average number per host cell. Multiple 48-well plates can be processed sequentially and the procedure can be completed in one working...... cell disruption or transcellular passage, to cause sepsis. Intracellular colonies are known to be clonal, originating from single invading UPEC. In our experimental setup, we found UPEC CFT073 intracellular bacterial colonies to be heterogeneous in size and present in nearly one third of the HKC-8...

  11. High-intensity tasks with external load in military applications: a review.

    Science.gov (United States)

    O'Neal, Eric K; Hornsby, Jared H; Kelleran, Kyle J

    2014-09-01

    This article provides a synopsis of the limited investigations examining the impact of external load (EL) on performance of high-intensity tasks under load (HITL), EL training intervention effects on HITL performance, and injuries from EL training. Repetitive lifting tasks and initiation of locomotion, such as rapidly moving from a prone position to sprinting appear to be more hindered by EL than maximal sprinting velocity and may explain why training with EL does not improve obstacle course or prolonged (200-300 yard shuttle) drills. EL training appears to offer very little if any benefit for HITL in lesser trained populations. This contrast results of multiple studies incorporating ≥ 3 weeks of prolonged hypergravity interventions (wearing EL during daily activities) in elite anaerobic athletes, indicating EL training stimulus is likely only beneficial to well-trained soldiers. Women and lesser trained individuals appear to be more susceptible to increased injury with EL training. A significant limitation concerning current HITL knowledge is the lack of studies incorporating trained soldiers. Future investigations concerning the effects of HITL on marksmanship, repetitive lifting biomechanics, efficacy of hypergravity training for military personnel, and kinematics of sprinting from tactical positions with various EL displacements and technique training are warranted.

  12. Detection of high biliary and fecal viral loads in patients with chronic hepatitis C virus infection.

    Science.gov (United States)

    Monrroy, Hugo; Angulo, Jenniffer; Pino, Karla; Labbé, Pilar; Miquel, Juan Francisco; López-Lastra, Marcelo; Soza, Alejandro

    2017-05-01

    The life cycle of the hepatitis C virus (HCV) is closely associated with lipid metabolism. Recently, NPC1L1 (a cholesterol transporter) has been reported to function as an HCV receptor. This receptor is expressed in the hepatocyte canalicular membrane and in the intestine; serving as a key transporter for the cholesterol enterohepatic cycle. We hypothesized that HCV might have a similar cycle, so we aimed to study the presence of HCV in bile and stools of infected patients. Blood, feces, and duodenal bile samples were collected from patients infected with HCV. The biliary viral load was normalized to the bile salt concentration of each sample and the presence of HCV core protein was also evaluated. A total of 12 patients were recruited. HCV RNA was detected in the bile from ten patients. The mean viral load was 2.5log10IU/60mg bile salt. In the stool samples, HCV RNA was detected in ten patients (mean concentration 2.7log10IU/g of feces). HCV RNA is readily detectable and is present at relatively high concentrations in the bile and stool samples of infected patients. This may be relevant as a source of infection in men who have sex with men. Biliary HCV secretion may perhaps play a role in the persistence of viral infection via an enterohepatic cycle of the virus or intrahepatic spread. Copyright © 2017 Elsevier España, S.L.U., AEEH y AEG. All rights reserved.

  13. Simplified formulations with high drug loads for continuous twin-screw granulation.

    Science.gov (United States)

    Meier, R; Thommes, M; Rasenack, N; Krumme, M; Moll, K-P; Kleinebudde, P

    2015-12-30

    As different batches of the same excipients will be intermixed during continuous processes, the traceability of batches is complicated. Simplified formulations may help to reduce problems related to batch intermixing and traceability. Twin-screw granulation with subsequent tableting was used to produce granules and tablets, containing drug, disintegrant and binder (binary and ternary mixtures), only. Drug loads up to 90% were achieved and five different disintegrants were screened for keeping their disintegration suitability after wetting. Granule size distributions were consistently mono-modal and narrow. Granule strength reached higher values, using ternary mixtures. Tablets containing croscarmellose-Na as disintegrant displayed tensile strengths up to 3.1MPa and disintegration times from 400 to 466s, resulting in the most robust disintegrant. Dissolution was overall complete and above 96% within 30 min. Na-starch glycolate offers tensile strengths up to 2.8MPa at disintegration times from 25s to 1031s, providing the broadest application window, as it corresponds in some parts to different definitions of orodispersible tablets. Tablets containing micronized crospovidone are not suitable for immediate release, but showed possibilities to produce highly drug loaded, prolonged release tablets. Tablets and granules from simplified formulations offer great opportunities to improve continuous processes, present performances comparable to more complicated formulations and are able to correspond to requirements of the authorities.

  14. Corner Separation Control by Boundary Layer Suction Applied to a Highly Loaded Axial Compressor Cascade

    Directory of Open Access Journals (Sweden)

    Yangwei Liu

    2014-11-01

    Full Text Available Control of corner separation has attracted much interest due to its improvement of performance and energy utilization in turbomachinery. Numerical studies have been performed under both design and off-design flow conditions to investigate the effects of boundary layer suction (BLS on corner separation in a highly loaded compressor cascade. Two new BLS slot configurations are proposed and a total of five suction slot configurations were studied and compared. Averaged static pressure rise, exit loss coefficient, passage blockage and flow turning angle have been given and compared systematically over a range of operation incidence angles. Distributions of significant loss removal, blade loading, exit deviation and total pressure loss at 3 degree and 7 degree incidence have also been studied. Under the same suction mass flows of 0.7% of the inlet mass flows, the pitchwise suction slot on the endwall shows a better optimal performance over the whole operation incidence among single suction slots. By using of the new proposed compound slot configuration with one spanwise slot on the blade suction side and one pitchwise slot on the endwall, the maximum reduction of total pressure loss at 7 degree incidence can be 39.4%.

  15. A Developed Methodology in Design of Highly Loaded Tandem Axial Flow Compressor Stage

    Directory of Open Access Journals (Sweden)

    Masoud Boroomand

    2016-01-01

    Full Text Available This study, primarily reports the development of a 3D design procedure for axial flow tandem compressor stages and then the method is used to design a highly loaded tandem stage. In order to investigate the effects of such arrangement, another stage with conventional loading with single blade for both rotor and stator rows is designed with similar specification. In order to ease the comparison of results, chord lengths and hub/shroud geometries are selected with the same dimensions. At the next stage a three dimensional numerical model is developed to predict the characteristic performance of both tandem and conventional stages. The model is validated with the experimental results of NASA-67 stage and the level of the accuracy of the model is presented. Employing the model to simulate the performance of both stages at design and offdesign operating points show that, tandem stage can provide higher pressure ratio with acceptable efficiency. In another word, tandem stage is capable having the same pressure ratio at lower rotational speed. The safe operation domain and loss mechanism in tandem stage are also discussed in this report.

  16. Behavior of Brazed W/Cu Mockup Under High Heat Flux Loads

    Science.gov (United States)

    Chen, Lei; Lian, Youyun; Liu, Xiang

    2014-03-01

    In order to transfer the heat from the armor to the coolant, tungsten has to be connected with a copper heat sink. The joint technology is the most critical issue for manufacturing plasma facing components. Consequently, the reliability of the joints should be verified by a great number of high-heat-flux (HHF) tests to simulate the real load conditions. W/Cu brazed joint technology with sliver free filler metal CuMnNi has been developed at Southwestern Institute of Physics (SWIP). Screening and thermal fatigue tests of one small-scale flat tile W/CuCrZr mockup were performed on a 60 kW electron-beam Material testing scenario (EMS-60) constructed recently at SWIP. The module successfully survived screening test with the absorbed power density (Pabs) of 2 MW/m2 to 10 MW/m2 and the following 1000 cycles at Pabs of 7.2 MW/m2 without hot spots and overheating zones during the whole test campaign. Metallurgy and SEM observations did not find any cracks at both sides and the interface, indicating a good bonding of W and CuCrZr alloy. In addition, finite element simulations by ANSYS 12.0 under experimental load conditions were performed and compared with experimental results.

  17. EFFECTS OF SLOTTED BLADING ON SECONDARY FLOW IN HIGHLY LOADED COMPRESSOR CASCADE

    Directory of Open Access Journals (Sweden)

    RAMZI MDOUKI

    2013-10-01

    Full Text Available With the aim to increase allowable blade loadings and enlarge stable operating range in highly loaded compressor, this work is carried out in order to explore the potential of passive control via slotted bladings in linear cascade configurations under both design and stall conditions. Through an extensive 2D-numerical study, the effects of location, width and slope of slots were analysed and the best configuration was identified. Based on the optimal slot, the 3D aerodynamic performances of cascade were studied and the influence of slotted blading to control endwall flow was investigated. Both 2D and 3D calculations are performed on steady RANS solver with standard k-epsilon turbulence model and low Mach number regime. The total loss coefficient, turning angle and flow visualizations on the blade and end-wall surfaces are adopted to describe the different configurations. The obtained results show, for 2D situation, that a maximum of 28.3% reduction in loss coefficient had been reached and the flow turning was increased with approximately 5°. Concerning 3D flow fields the slots marked their benefit at large incoming flow angles which delays the separation on both end wall and blade suction surface at mid span. However, at design conditions, the slotted blades are not able to control secondary flows near the wall and so, lose their potential.

  18. A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

    Science.gov (United States)

    Zhou, Junfang; Fang, Wenhong; Yang, Xianle; Zhou, Shuai; Hu, Linlin; Li, Xincang; Qi, Xinyong; Su, Hang; Xie, Layue

    2012-01-01

    Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by "white tail" and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of "white tail" but of non-bacterial origin, the present disease was named as "bacterial white tail disease (BWTD)". Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system.

  19. A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

    Directory of Open Access Journals (Sweden)

    Junfang Zhou

    Full Text Available Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by "white tail" and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905 was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN, white tail disease (WTD or penaeid white tail disease (PWTD. To differentiate from such diseases as with a sign of "white tail" but of non-bacterial origin, the present disease was named as "bacterial white tail disease (BWTD". Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system.

  20. Assessing the effects of salmon farming seabed enrichment using bacterial community diversity and high-throughput sequencing.

    Science.gov (United States)

    Dowle, Eddy; Pochon, Xavier; Keeley, Nigel; Wood, Susanna A

    2015-08-01

    Aquaculture is an extremely valuable and rapidly expanding sector of the seafood industry. The sediment below active aquaculture farms receives inputs of organic matter from uneaten food and faecal material and this has led to concerns related to environmental sustainability. The impacts of organic enrichment on macrobenthic infauna are well characterized; however, much less is known about effect on bacterial communities. In this study, sediment, macrobenthic infauna samples and environmental data were collected along an enrichment gradient radiating out from a Chinook salmon (Oncorhynchus tshawytscha) farm (Marlborough Sounds; New Zealand). DNA and RNA were extracted and 16S rRNA metabarcodes from bacterial communities characterized using high-throughput sequencing. Desulfobacterales dominated at the cage (DNA and RNA), and at sites 50 m (DNA and RNA) and 150 m (RNA) from the farm. In contrast, unclassified bacteria from the class Gammaproteobacteria were the most abundant taxa at control sites (625 and 4000 m). Pronounced differences among DNA and RNA samples occurred at the cage site where Desulfobacterales abundance was markedly higher in RNA samples. There were strong correlations between shifts in bacterial communities and total organic matter and redox. This suggests that bacterial composition is strongly influenced by organic enrichment, a trait that may make them useful for assessing impacts associated with aquaculture farms. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. FEATURES OF PERCEPTION OF LOADING ELEMENTS OF THE RAILWAY TRACK AT HIGH SPEEDS OF THE MOVEMENT

    Directory of Open Access Journals (Sweden)

    D. M. Kurhan

    2015-03-01

    Full Text Available Purpose. Increase the train speeds movements requires not only the appropriate technical solutions, but also methodological-calculated. Most of the models and methodologies used for solving problems of stress-strain state of the railroad tracks, are based on assumptions and hypotheses adequate only for certain speeds. In the framework of this work will be discussed theoretical background of the changing nature of perceptual load elements of the railway track at high speeds and investigated the numeric parameters of the processes by means of mathematical modeling. As a practical purposes is expected to provide the levels of train speed, the boundaries of which can reasonably exclude the possibility of occurrence of the considered effects. Methodology. To achieve these objectives was used principal new model of railway track based on wave propagation theory stresses in the elastic system to study the impact of the movable load, take into account that the deflection in a particular section of the road starts even while the wheels at some distance, and moving the wheels farther from the selected section of the wave front elastic strain continues to spread. According to the results of simulations explores the changing shape of the wave front voltages in time for the foundation under the rail. If the train speeds substantially less than the velocity propagation of elastic waves, the wheel remains in the area implemented deformations. Findings. Alternative calculations for various parameters of the railway track (especially for different soil conditions determined the levels of train speed, the boundaries of which can reasonably exclude the possibility of occurrence of the considered effects. Originality. The proposed theoretical study and implementation in the form of mathematical models for processes that occur in the perception of load elements of the railway track at high speeds. Practical value. According to simulation results obtained levels of

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  3. Evaluation by respirometry of the loading capacity of a high rate vermicompost bed for treating sewage sludge.

    Science.gov (United States)

    Clarke, William P; Taylor, Michael; Cossins, Rowan

    2007-09-01

    This study examines high rate vermicomposting of sewage sludge using high stocking densities of earthworms. To examine the loading capacity, two vermicompost beds were established in identical 0.84 m diameter reactors, one loaded at an average rate of 10 kg-wet-sludge-mixture m(-2) day(-1) (0.5 kg-carbon m(-2) day(-1)), the other loaded at 20 kg-wet-sludge-mixture m(-2) day(-1) (1 kg-carbon m(-2) day(-1)). The sludge mixture was from a commercial vermicomposting company (Vermitech) and contained 80-90% sludge and 10-20% green waste and clay. The beds were operated in fed-batch mode for 38 days, and then monitored for a further 12 days without any further sludge loading. Earthworms (Eisenia fetida) were added once or twice weekly over the 38 days loading period to gradually decrease the ratio of sludge loading rate to total earthworm biomass. By adding earthworm incrementally, the feeding rate ranged from 3.9 to 1.25 kg-wet-sludge kg-earthworm(-1) day(-1) for the full load experiment and 2-0.62 kg-wet-sludge kg-earthworm(-1) day(-1) for the half load experiment. The extent of degradation was estimated by fitting a 1st order model to the CO2 production rate from the beds. Based on the 1st order model, 53+/-20% (95% CI) and 68+/-4% of the organic carbon was converted to CO2 -C in the full load and half load experiments respectively. The CO2 production rate in the half load experiment became stable and repeatable when the total earthworm biomass reached 5.4 kg, corresponding to a feed rate of 1.04 kg-wet-sludge-mixture kg-earthworm(-1) day(-1). In contrast, the rate of CO2 production was still climbing and traces of methane were evident in the full load experiment at the end of the 38 day loading period. The experiments indicate that high rate vermicomposting beds are sustainable providing the feeding rate does not exceed approximately 1 kg-wet-sludge kg-earthworm(-1) day(-1).

  4. Reinstating lead for high-loaded efficient negative electrode for rechargeable sodium-ion battery

    Science.gov (United States)

    Darwiche, Ali; Dugas, Romain; Fraisse, Bernard; Monconduit, Laure

    2016-02-01

    Due to its weight and toxicity, Pb is usually not considered as possible anode for Li- and Na-ion (NIBs) batteries. Nevertheless the toxicity is related to specific applications and its recycling is more than 99% which is one of the highest recycling rates on the planet where no other power source is utilized in more applications with such sustainability. For this reason, we have investigated micrometric lead particles as electrode for NIBs in an ether-based electrolyte (1 M NaPF6 in diglyme). The cyclability, coulombic efficiency and rate capability of lead were unexpected. A high loaded lead electrode with 98%wt of Pb and only 1% of carbon additive showed i) a capacity retention of 464 mA h/g after 50 cycles with only 1.5% of capacity loss, which represents a high volumetric capacity of 5289 mA h/cm3 due to the high density of Pb and ii) a very interesting capacity retention even at high current rate (1950 mA/g). In situ XRD study confirmed a sodiation-desodiation process in four steps. Preliminary tests in Pb//Na3V2(PO4)2F3 full cells showed promising results demonstrating that Pb could be a practical candidate for future high energy density Na-ion batteries with an efficient sodiated or non sodiated positive electrode.

  5. Detection and quantification of bacterial autofluorescence at the single-cell level by a laboratory-built high-sensitivity flow cytometer.

    Science.gov (United States)

    Yang, Lingling; Zhou, Yingxing; Zhu, Shaobin; Huang, Tianxun; Wu, Lina; Yan, Xiaomei

    2012-02-07

    Cellular autofluorescence can affect the sensitivity of fluorescence microscopic or flow cytometric assays by interfering with or even precluding the detection of low-level specific fluorescence. Here we developed a method to detect and quantify bacterial autofluorescence in the green region of the spectrum at the single-cell level using a laboratory-built high-sensitivity flow cytometer (HSFCM). The detection of the very weak bacterial autofluorescence was confirmed by analyzing polystyrene beads of comparable and larger size than bacteria in parallel. Dithionite reduction and air re-exposure experiments verified that the green autofluorescence mainly originates from endogenous flavins. Bacterial autofluorescence was quantified by calibrating the fluorescence intensity of nanospheres with known FITC equivalents, and autofluorescence distribution was generated by analyzing thousands of bacterial cells in 1 min. Among the eight bacterial strains tested, it was found that bacterial autofluorescence can vary from 80 to 1400 FITC equivalents per cell, depending on the bacterial species, and a relatively large cell-to-cell variation in autofluorescence intensity was observed. Quantitative measurements of bacterial autofluorescence provide a reference for the background signals that can be expected with bacteria, which is important in guiding studies of low-level gene expression and for the detection of low-abundance biological molecules in individual bacterial cells. This paper presents the first quantification of bacterial autofluorescence in FITC equivalents.

  6. A Short-Term and High-Resolution System Load Forecasting Approach Using Support Vector Regression with Hybrid Parameters Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Huaiguang [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-25

    This work proposes an approach for distribution system load forecasting, which aims to provide highly accurate short-term load forecasting with high resolution utilizing a support vector regression (SVR) based forecaster and a two-step hybrid parameters optimization method. Specifically, because the load profiles in distribution systems contain abrupt deviations, a data normalization is designed as the pretreatment for the collected historical load data. Then an SVR model is trained by the load data to forecast the future load. For better performance of SVR, a two-step hybrid optimization algorithm is proposed to determine the best parameters. In the first step of the hybrid optimization algorithm, a designed grid traverse algorithm (GTA) is used to narrow the parameters searching area from a global to local space. In the second step, based on the result of the GTA, particle swarm optimization (PSO) is used to determine the best parameters in the local parameter space. After the best parameters are determined, the SVR model is used to forecast the short-term load deviation in the distribution system.

  7. Multi-mode controller IC for soft-switched flyback converter with high efficiency over the entire load range

    Institute of Scientific and Technical Information of China (English)

    Hai CHEN; Meng-lian ZHAO; Xiao-bo WU; Xiao-lang YAN

    2008-01-01

    This paper presents a multi-mode control scheme for a soft-switched flyback converter to achieve high efficiency and excellent load regulation over the entire load range. At heavy load, critical conduction mode with valley switching (CCMVS) is employed to realize soft switching so as to reduce turn-on loss of power switch as well as conducted electromagnetic interference (EMI). At light load, the converter operates in discontinuous conduction mode (DCM) with valley switching and adaptive off-time control (AOT) to limit the switching frequency range and maintain load regulation. At extremely light load or in standby mode,burst mode operation is adopted to provide low power consumption through reducing both switching frequency and static power dissipation of the controller. The multi-mode control is implemented by an oscillator whose pulse duration is adjusted by output feedback. An accurate valley switching control circuit guarantees the minimum turn-on voltage drop of power switch. The pro-totype of the controller IC was fabricated in a 1.5um BiCMOS process and applied to a 310 V/20 V, 90 W flyback DC/DC converter circuitry. Experimental results showed that all expected functions were realized successfully. The flyback converter achieved a high efficiency of over 80% from full load down to 2.5 W, with the maximum reaching 88.8%, while the total power consumption in standby mode was about 300 mW.

  8. A high-throughput sequencing ecotoxicology study of freshwater bacterial communities and their responses to tebuconazole.

    Science.gov (United States)

    Pascault, Noémie; Roux, Simon; Artigas, Joan; Pesce, Stéphane; Leloup, Julie; Tadonleke, Rémy D; Debroas, Didier; Bouchez, Agnès; Humbert, Jean-François

    2014-12-01

    The pollution of lakes and rivers by pesticides is a growing problem worldwide. However, the impacts of these substances on microbial communities are still poorly understood, partly because next-generation sequencing (NGS) has rarely been used in an ecotoxicology context to study bacterial communities despite its interest for accessing rare taxa. Microcosm experiments were carried out to evaluate the effects of tebuconazole (TBZ) on the structure and composition of bacterial communities from two types of freshwater ecosystem (lakes and rivers) with differing histories of pollutant contamination (pristine vs. previously exposed sites). Pyrosequencing revealed that bacterial diversity was higher in the river than in the lakes and in previously exposed sites than in pristine sites. Lakes and river stations shared very few OTUs, and differences at the phylum level were identified between these ecosystems (i.e. the relative importance of Actinobacteria and Gammaproteobacteria). Despite differences between these ecosystems and their contamination history, no significant effect of TBZ on bacterial community structure or composition was observed. Compared to functional parameters that displayed variable responses, we demonstrated that a combination of classical methods and NGS is necessary to investigate the ecotoxicological responses of microbial communities to pollutants.

  9. Chemical communication of antibiotic resistance by a highly resistant subpopulation of bacterial cells.

    Directory of Open Access Journals (Sweden)

    Omar M El-Halfawy

    Full Text Available The overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. Bacterial heteroresistance to antibiotics has been documented for several opportunistic Gram-negative bacteria, but the mechanism of heteroresistance is unclear. We use Burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin B (PmB and also other bactericidal antibiotics. Here, we report that B. cenocepacia is heteroresistant to PmB. Population analysis profiling also identified B. cenocepacia subpopulations arising from a seemingly homogenous culture that are resistant to higher levels of polymyxin B than the rest of the cells in the culture, and can protect the more sensitive cells from killing, as well as sensitive bacteria from other species, such as Pseudomonas aeruginosa and Escherichia coli. Communication of resistance depended on upregulation of putrescine synthesis and YceI, a widely conserved low-molecular weight secreted protein. Deletion of genes for the synthesis of putrescine and YceI abrogate protection, while pharmacologic inhibition of putrescine synthesis reduced resistance to polymyxin B. Polyamines and YceI were also required for heteroresistance of B. cenocepacia to various bactericidal antibiotics. We propose that putrescine and YceI resemble "danger" infochemicals whose increased production by a bacterial subpopulation, becoming more resistant to bactericidal antibiotics, communicates higher level of resistance to more sensitive members of the population of the same or different species.

  10. High-fat nutrition reduces hepatic damage following exposure to bacterial DNA and hemorrhagic shock.

    NARCIS (Netherlands)

    Luyer, M.D.; Derikx, J.P.; Beyaert, R.; Hadfoune, M.; Kuppevelt, A.H.M.S.M. van; Dejong, C.H.; Heineman, E.; Buurman, W.A.; Greve, J.W.

    2009-01-01

    BACKGROUND/AIMS: Bacterial infection combined with hypotension results in exacerbation of the inflammatory response with release of interferon (IFN) gamma. This excessive inflammation may lead to development of hepatic damage and liver failure. This study investigates the effect of dietary lipids on

  11. Consolidated bioprocessing (CBP) of AFEX™-pretreated corn stover for ethanol production using Clostridium phytofermentans at a high solids loading.

    Science.gov (United States)

    Jin, Mingjie; Gunawan, Christa; Balan, Venkatesh; Dale, Bruce E

    2012-08-01

    Consolidated bioprocessing (CBP) using Clostridium phytofermentans (ATCC 700394) on ammonia fiber expansion (AFEX™)-treated corn stover (AFEX™-CS) at a low solids loading showed promising results [Jin et al. (2011) Biotechnol Bioeng 108(6): 1290-1297]. However, industrial relevant process requires high solids loading. Therefore, we studied high solids loading CBP performance on AFEX™-CS. The factors potentially affecting the performance including solids loading, CBP products acetate and ethanol, and degradation products resulting from pretreatment were investigated. At 4% (w/w) glucan loading, C. phytofermentans performed well on AFEX™-CS with no nutrients supplementation and reached similar sugar conversions as a fermentation with nutrients supplementation. A glucan conversion of 48.9% and a xylan conversion of 77.9% were achieved after 264 h with 7.0 g/L ethanol and 8.8 g/L acetate produced. Relatively high concentrations of acetate produced at high solids loading was found to be the major factor limiting the CBP performance. Degradation products in AFEX™-CS helped enhance ethanol production.

  12. Effect of Temperature on the Void Growth in Pure Aluminium at High Strain-Rate Loading

    Institute of Scientific and Technical Information of China (English)

    QI Mei-Lan; HE Hong-Liang; YAN Shi-Lin

    2007-01-01

    @@ With the environment temperature varying from 273K to 773K, the dynamic process of void growth in pure aluminium at high strain-rate loading is calculated based on the dynamic growth equation of a void with internal pressure. The result shows that the effect of temperature on the growth of void should be emphasized. Because the initial pressure of void with gas will increase and the viscosity of materials will decrease with the rising of temperature, the growth of void is accelerated. Furthermore, material inertia restrains the growth of void evidently when the diameter exceeds 10μm. The effect of surface tension is very weak in the whole process of void growth.

  13. Highly sensitive optical biosensor based on silicon-microring-resonator-loaded Mach–Zehnder interferometer

    Science.gov (United States)

    Yoshida, Soichiro; Ishihara, Shintaro; Arakawa, Taro; Kokubun, Yasuo

    2017-04-01

    We propose and demonstrate a novel biosensor based on a silicon-single-microring-resonator-loaded Mach–Zehnder interferometer (MRR-MZI), and discuss the design of the sensor theoretically. Owing to the combination of an MZI and the enhanced phase change in a microring resonator (MRR), high sensitivity is expected to be realized. The designed MRR-MZI sensor is fabricated using a CMOS-compatible process, and its sensing characteristics are measured using ethanol solutions with a concentration of less than 3 wt % and avidin solutions. The sensitivity of the MRR-MZI to changes in the environmental refractive index is increased by approximately 50 times compared with that of a simple MRR. In addition, avidin solution with a concentration as low as 20 pM was successfully detected.

  14. Toroidal cell and battery. [storage battery for high amp-hour load applications

    Science.gov (United States)

    Nagle, W. J. (Inventor)

    1981-01-01

    A toroidal storage battery designed to handle relatively high amp-hour loads is described. The cell includes a wound core disposed within a pair of toroidal channel shaped electrodes spaced apart by nylon insulator. The shape of the case electrodes of this toroidal cell allows a first planar doughnut shaped surface and the inner cylindrical case wall to be used as a first electrode and a second planar doughnut shaped surface and the outer cylindrical case wall to be used as a second electrode. Connectors may be used to stack two or more toroidal cells together by connecting substantially the entire surface area of the first electrode of a first cell to substantially the entire surface area of the second electrode of a second cell. The central cavity of each toroidal cell may be used as a conduit for pumping a fluid through the toroidal cell to thereby cool the cell.

  15. Vibration measurement through high speed vision system in a civil structure under impact loading

    Science.gov (United States)

    Ferrer, Belén; García, Juan I.; Roig, Ana B.; Mas, David

    2014-05-01

    The method presented in this work is a simple, cheap and non-contact method. It is based on image processing using a circular target. It has subpixel accuracy and it only needs a low cost high-speed camera and a tripod. In the work presented in this paper, a Casio Exilim camera was used to measure the vibration of a pedestrian bridge. An impact load was applied on the bridge through one person jumping in the middle of the bridge. Tracking of the circle border give the center trajectory and therefore the displacement and frequency of the movement. Some accelerometers were used as a contrast device for the frequency. The displacement obtained by our procedure was previously checked in laboratory using a micrometric bench. The results show that this method is suitable for measuring successfully the vibration of civil structures.

  16. Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads

    Directory of Open Access Journals (Sweden)

    Marco Romano

    2014-07-01

    Full Text Available This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material.

  17. High-Tip-Speed, Low-Loading Transonic Fan Stage. Part 1: Aerodynamic and Mechanical Design

    Science.gov (United States)

    Wright, L. C.; Vitale, N. G.; Ware, T. C.; Erwin, J. R.

    1973-01-01

    A high-tip-speed, low-loading transonic fan stage was designed to deliver an overall pressure ratio of 1.5 with an adiabatic efficiency of 86 percent. The design flow per unit annulus area is 42.0 pounds per square foot. The fan features a hub/tip ratio of 0.46, a tip diameter of 28.74 in. and operates at a design tip speed of 1600 fps. For these design conditions, the rotor blade tip region operates with supersonic inlet and supersonic discharge relative velocities. A sophisticated quasi-three-dimensional characteristic section design procedure was used for the all-supersonic sections and the inlet of the midspan transonic sections. For regions where the relative outlet velocities are supersonic, the blade operates with weak oblique shocks only.

  18. Training Load Monitoring Algorithms on Highly Sub-Metered Home Electricity Consumption Data

    Institute of Scientific and Technical Information of China (English)

    Mario Berges; Ethan Goldman; H. Scott Matthews; Lucio Soibelman

    2008-01-01

    The growing interest in energy-efficient buildings is driving changes in investment, design, and occupant behavior. To better focus cost and resource conservation efforts, electricity consumption feedback can be used to provide motivation, guidance, and verification. Disaggregating by end-use helps both con-sumers and producers to identify targets for conservation. While hardware-based sub-metering is costly and labor-intensive, non-intrusive load monitoring (NILM) is capable of gathering detailed energy-use data with minimal equipment cost and installation time. However, variations in measurements between metering de-vices complicate the process of compiling the necessary appliance profiles. Future work involves the devel-opment of NILM algorithms using sensor fusion and detailed appliance-level data gathered from a highly-sensed house currently being constructed near Pittsburgh, Pennsylvania.

  19. Degradation and mineralization of high-molecular-weight polycyclic aromatic hydrocarbons by defined fungal-bacterial cocultures

    Energy Technology Data Exchange (ETDEWEB)

    Boonchan, S.; Britz, M.L.; Stanley, G.A.

    2000-03-01

    This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10,201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO{sub 2} by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization, and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula.

  20. Degradation and mineralization of high-molecular-weight polycyclic aromatic hydrocarbons by defined fungal-bacterial cocultures.

    Science.gov (United States)

    Boonchan, S; Britz, M L; Stanley, G A

    2000-03-01

    This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10, 201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO(2) by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization (53% of added [(14)C]benzo[a]pyrene was recovered as (14)CO(2) in 100 days), and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula.

  1. Bacterial microflora isolated from the bark surface of poplars growing in areas where air pollution is very high

    Directory of Open Access Journals (Sweden)

    Krystyna Przybył

    2015-05-01

    Full Text Available In the autumn of 1976 bacteria of the genera Bacillus, Pseudomonas, Flavobacterium, Erwinia and Cellulomonas were isolated from the bark surface of poplars growing in protective belts around several industrial plants. It was found that the qualitative and quantitative composition of the surface bacterial microflora changes in dependence on the degree of resistance of the poplars to the action of the dust emitted by the industrial establishment and containing high amounts of heavy metals.

  2. Removal of high organic loads from winery wastewater by aquatic plants.

    Science.gov (United States)

    Zimmels, Y; Kirzhner, F; Schreiber, J

    2008-09-01

    Laboratory- and field-scale purification tests of raw and diluted winery wastewater (WWW) were carried out using aquatic plants at high organic loads. The laboratory tests were performed using artificial light at 1800 to 1900 lux. The objective of the current study was to define the potential of floating and emergent aquatic macrophytes and the microorganisms attached to their roots, to reduce high organic loads that characterize WWW, thereby providing, for these effluents, an effective treatment and management system. These microorganisms are believed to have a major role in the treatment process. In this context, the potential of floating and emergent macrophytes to improve the water quality of raw compared with diluted WWW was evaluated. In raw WWW (chemical oxygen demand [COD] 5.6 g/L),growth inhibition of both water hyacinth (Eichhornia crassipes) and water pennywort (Hydrocotyle umbellata) was observed. A 1:1 dilution of WWW with fresh (tap) water facilitated growth of these plants. At this dilution level, growth of pennywort was limited, while that of water hyacinth was robust. In terms of reductions in biochemical oxygen demand, COD, and total suspended solids, both water hyacinth and pennywort performed better in diluted compared with raw WWW. At 1:1 and 1:3 dilution, 95.9 to 97% of the COD was removed after 23 days, in the presence of Hydrocotyle and Eichhornia plants and aeration. The capacity of new emergent plants to remove high organic loads from WWW, at enhanced kinetics, was demonstrated. This unique property was tested and compared with the role of the gravel media that support growth of the high-capacity emergent plants. In the presence of reed and salt marsh plants, 83 to 99% of the COD was removed within a period of 24 to 29 days, at 1.5:1 dilution. The new emergent plants proved to be effective, even at record high levels of COD. At an initial level of 16,460 mg/L, the COD was brought down to 2870 mg/L after 24 days (82.6% removal), while 12

  3. Protein growth factors loaded highly porous chitosan scaffold: A comparison of bone healing properties

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Samit K., E-mail: samitnandi1967@gmail.com [Department of Veterinary Surgery and Radiology, West Bengal University of Animal and Fishery Sciences, Kolkata (India); Kundu, Biswanath, E-mail: biswa_kundu@rediffmail.com [Bioceramics and Coating Division, CSIR—Central Glass and Ceramic Research Institute, Kolkata (India); Basu, Debabrata [Bioceramics and Coating Division, CSIR—Central Glass and Ceramic Research Institute, Kolkata (India)

    2013-04-01

    Present study aimed to investigate and compare effectiveness of porous chitosan alone and in combination with insulin like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) in bone healing. Highly porous (85 ± 2%) with wide distribution of macroporous (70–900 μm) chitosan scaffolds were fabricated as bone substitutes by employing a simple liquid hardening method using 2% (w/v) chitosan suspension. IGF-1 and BMP-2 were infiltrated using vacuum infiltration with freeze drying method. Adsorption efficiency was found to be 87 ± 2 and 90 ± 2% for BMP-2 and IGF-1 respectively. After thorough material characterization (pore details, FTIR and SEM), samples were used for subsequent in vivo animal trial. Eighteen rabbit models were used to evaluate and compare control (chitosan) (group A), chitosan with IGF-1 (group B) and chitosan with BMP-2 (group C) in the repair of critical size bone defect in tibia. Radiologically, there was evidence of radiodensity in defect area from 60th day (initiated on 30th day) in groups B and C as compared to group A and attaining nearly bony density in most of the part at day 90. Histological results depicted well developed osteoblastic proliferation around haversian canal along with proliferating fibroblast, vascularization and reticular network which was more pronounced in group B followed by groups C and A. Fluorochrome labeling and SEM studies in all groups showed similar outcome. Hence, porous chitosan alone and in combination with growth factors (GFs) can be successfully used for bone defect healing with slight advantage of IGF-1 in chitosan samples. - Highlights: ► Fabrication and characterization of porous chitosan with or without IGF-1 and BMP-2 ► Highly porous growth factor loaded chitosan studied in animal subjects for 3 months ► Parameters studied: histopathology, radiology and fluorochrome labeling ► IGF-1 loaded porous chitosan found to be very effective for bone defect healing.

  4. Multi-Mission Capable, High g Load mW RPS

    Energy Technology Data Exchange (ETDEWEB)

    John C. Bass; Nathan Hiller; Velimir Jovanovic; Norbert B. Elsner

    2007-05-23

    Over the past few years Hi-Z has been developing a wide range of mW generators and life testing thermoelectric modules for the Department of Energy (DOE) to fulfill requirements by NASA Ames and other agencies. The purpose of this report is to determine the capabilities of a wide range of mW generators for various missions. In the 1st quarterly report the power output of various mW generators was determined via thermal and mechanical modeling. The variable attributes of each generator modeled were: the number of RHUs (1-8), generator outer diameter (1.25-4 in.), and G-load (10, 500, or 2,000). The resultant power output was as high as 180 mW for the largest generator with the lowest Gload. Specifically, we looked at the design of a generator for high G loading that is insulated with Xenon gas and multifoil solid insulation. Because the design of this new generator varied considerably from the previous generator design, it was necessary to show in detail how it is to be assembled, calculate them as of the generator and determine the heat loss from the system. A new method of assembling the RHU was also included as part of the design. As a side issue we redesigned the test stations to provide better control of the cold sink temperature. This will help in reducing the test data by eliminating the need to 'normalize' the data to a specific temperature. In addition these new stations can be used to simulate the low ambient temperatures associated with Mars and other planets.

  5. Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ding Youliang

    2016-01-01

    Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

  6. A comprehensive insight into bacterial virulence in drinking water using 454 pyrosequencing and Illumina high-throughput sequencing.

    Science.gov (United States)

    Huang, Kailong; Zhang, Xu-Xiang; Shi, Peng; Wu, Bing; Ren, Hongqiang

    2014-11-01

    In order to comprehensively investigate bacterial virulence in drinking water, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential pathogenic bacteria and virulence factors (VFs) in a full-scale drinking water treatment and distribution system. 16S rRNA gene pyrosequencing revealed high bacterial diversity in the drinking water (441-586 operational taxonomic units). Bacterial diversity decreased after chlorine disinfection, but increased after pipeline distribution. α-Proteobacteria was the most dominant taxonomic class. Alignment against the established pathogen database showed that several types of putative pathogens were present in the drinking water and Pseudomonas aeruginosa had the highest abundance (over 11‰ of total sequencing reads). Many pathogens disappeared after chlorine disinfection, but P. aeruginosa and Leptospira interrogans were still detected in the tap water. High-throughput sequencing revealed prevalence of various pathogenicity islands and virulence proteins in the drinking water, and translocases, transposons, Clp proteases and flagellar motor switch proteins were the predominant VFs. Both diversity and abundance of the detectable VFs increased after the chlorination, and decreased after the pipeline distribution. This study indicates that joint use of 454 pyrosequencing and Illumina sequencing can comprehensively characterize environmental pathogenesis, and several types of putative pathogens and various VFs are prevalent in drinking water.

  7. Nanostructured poly (lactic acid) electrospun fiber with high loadings of TiO2 nanoparticles: Insights into bactericidal activity and cell viability.

    Science.gov (United States)

    Toniatto, T V; Rodrigues, B V M; Marsi, T C O; Ricci, R; Marciano, F R; Webster, T J; Lobo, A O

    2017-02-01

    Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.

  8. Plasma PCSK9 concentrations during an oral fat load and after short term high-fat, high-fat high-protein and high-fructose diets

    Directory of Open Access Journals (Sweden)

    Cariou Bertrand

    2013-01-01

    Full Text Available Abstract Background PCSK9 (Proprotein Convertase Subtilisin Kexin type 9 is a circulating protein that promotes hypercholesterolemia by decreasing hepatic LDL receptor protein. Under non interventional conditions, its expression is driven by sterol response element binding protein 2 (SREBP2 and follows a diurnal rhythm synchronous with cholesterol synthesis. Plasma PCSK9 is associated to LDL-C and to a lesser extent plasma triglycerides and insulin resistance. We aimed to verify the effect on plasma PCSK9 concentrations of dietary interventions that affect these parameters. Methods We performed nutritional interventions in young healthy male volunteers and offspring of type 2 diabetic (OffT2D patients that are more prone to develop insulin resistance, including: i acute post-prandial hyperlipidemic challenge (n=10, ii 4 days of high-fat (HF or high-fat/high-protein (HFHP (n=10, iii 7 (HFruc1, n=16 or 6 (HFruc2, n=9 days of hypercaloric high-fructose diets. An acute oral fat load was also performed in two patients bearing the R104C-V114A loss-of-function (LOF PCSK9 mutation. Plasma PCSK9 concentrations were measured by ELISA. For the HFruc1 study, intrahepatocellular (IHCL and intramyocellular lipids were measured by 1H magnetic resonance spectroscopy. Hepatic and whole-body insulin sensitivity was assessed with a two-step hyperinsulinemic-euglycemic clamp (0.3 and 1.0 mU.kg-1.min-1. Findings HF and HFHP short-term diets, as well as an acute hyperlipidemic oral load, did not significantly change PCSK9 concentrations. In addition, post-prandial plasma triglyceride excursion was not altered in two carriers of PCSK9 LOF mutation compared with non carriers. In contrast, hypercaloric 7-day HFruc1 diet increased plasma PCSK9 concentrations by 28% (p=0.05 in healthy volunteers and by 34% (p=0.001 in OffT2D patients. In another independent study, 6-day HFruc2 diet increased plasma PCSK9 levels by 93% (p Conclusions Plasma PCSK9 concentrations vary

  9. DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Energy Technology Data Exchange (ETDEWEB)

    Pi Changming; Yan Wei; Zhang Ke; Li Wenhong, E-mail: wenhongli@fudan.edu.c [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)

    2010-08-15

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 {mu}m CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency. (semiconductor integrated circuits)

  10. Fermentative high-titer ethanol production from Douglas-fir forest residue without detoxification using SPORL: high SO2 loading at low temperature

    Science.gov (United States)

    Feng Gu; William Gilles; Roland Gleisner; J.Y. Zhu

    2016-01-01

    This study evaluated high sulfur dioxide (SO2) loading in applying Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) to Douglas-fir forest residue (FS-10) for ethanol production through yeast fermentation. Three pretreatments were conducted at 140

  11. SEMICONDUCTOR INTEGRATED CIRCUITS: DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Science.gov (United States)

    Changming, Pi; Wei, Yan; Ke, Zhang; Wenhong, Li

    2010-08-01

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 μm CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency.

  12. Hierarchical sulfur electrodes as a testing platform for understanding the high-loading capability of Li-S batteries

    Science.gov (United States)

    Chung, Sheng-Heng; Chang, Chi-Hao; Manthiram, Arumugam

    2016-12-01

    Lithium-sulfur (Li-S) batteries are considered as an attractive electrochemical energy storage system due to the high theoretical capacity of sulfur (1,675 mA h g-1). However, high-loading sulfur cathodes would need to be employed for the Li-S cells to be practical, but the resulting poor cell cyclability and severe electrode degradation hamper their development. Here, we present a hierarchical sulfur cathode as a testing platform for understanding the high-loading capability of Li-S batteries. The hierarchical cathode presents good electrochemical utilization of above 70%, stable cyclability for 500-1,000 cycles, and high sulfur loadings of 4.2-10.0 mg cm-2. The exploration of the activation and the polysulfide-retention processes of the high-loading cathodes illustrates that the electrochemical stability mainly results from the stabilization of dissolved polysulfides within the cathode region as the electrochemically active catholyte. Therefore, the utilization of stabilized polysulfide migration might be a meaningful opportunity for designing high-loading cathodes and further improving their electrochemical stability and long-term cyclability.

  13. Study on load forecasting to data centers of high power density based on power usage effectiveness

    Science.gov (United States)

    Zhou, C. C.; Zhang, F.; Yuan, Z.; Zhou, L. M.; Wang, F. M.; Li, W.; Yang, J. H.

    2016-08-01

    There is usually considerable energy consumption in data centers. Load forecasting to data centers is in favor of formulating regional load density indexes and of great benefit to getting regional spatial load forecasting more accurately. The building structure and the other influential factors, i.e. equipment, geographic and climatic conditions, are considered for the data centers, and a method to forecast the load of the data centers based on power usage effectiveness is proposed. The cooling capacity of a data center and the index of the power usage effectiveness are used to forecast the power load of the data center in the method. The cooling capacity is obtained by calculating the heat load of the data center. The index is estimated using the group decision-making method of mixed language information. An example is given to prove the applicability and accuracy of this method.

  14. Effect of cyclic high loading rates on the fatigue strength of aluminum-based composites

    Science.gov (United States)

    Calderon Arteaga, Hermes Eskander

    The study of fatigue under high loading rates is of great interest in the complete characterization of a new series of composites with Al-Cu-Mg matrix reinforced with AlB2 dispersoids. Homogeneous and functionally graded composites were prepared via gravity and centrifugal casting, respectively. Through centrifugal casting a gradual variation of the volume fraction of reinforcing particles along the cross section was obtained. In specific fabrication conditions, even complete segregation of the reinforcement particles was achieved. Charpy impact tests as well as hardness tests were conducted to assess the composite strength as a function of the weight percent of boron. The tensile properties of gravity cast samples were obtained. Then for both casting conditions, simple edge-notched bend SE(B) specimens were tested under fatigue conditions (three-point bending). The results from impact and hardness tests allowed identifying an interaction between the Mg dissolved in the matrix and the diborides. This interaction, which has never been reported before, was responsible for the strength reduction observed. It was assumed that a substitutional diffusion of Al by Mg atoms in the hp3 structure of diboride was causing the strength reduction, and three approaches were developed to estimate the amount of Mg depleted from the matrix by the diborides during the composite processing. Gravity cast samples were more sensitive to monotonic damage due to fatigue loads where compared with functionally-graded composites. Contrary to the centrifugal cast samples, gravity samples were also affected by the loading rate. The Mg-AlB2 interaction was also responsible for the reduction in the fatigue resistance as the weight percent of boron increased in both types of composites; regression models were obtained to predict the crack growth curve slope change as function of the boron level. The particle distribution showed to affect the crack growth behavior of the FGMs, decreasing the

  15. Synthesis of High Valence Silver-Loaded Mesoporous Silica with Strong Antibacterial Properties

    Science.gov (United States)

    Chen, Chun-Chi; Wu, Hsin-Hsien; Huang, Hsin-Yi; Liu, Chen-Wei; Chen, Yi-Ning

    2016-01-01

    A simple chemical method was developed for preparing high valence silver (Ag)-loaded mesoporous silica (Ag-ethylenediaminetetraacetic acid (EDTA)-SBA-15), which showed strong antibacterial activity. Ag-EDTA-SBA-15 exhibited stronger and more effective antibacterial activity than commercial Ag nanoparticles did, and it offered high stability of high valence silver in the porous matrix and long-lasting antibacterial activity. The synthesized materials were characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) analysis, and transmission electron microscopy (TEM). Ag existed in both surface complexation and Ag particles. EDTA anchored within a porous structure chelated Ag ions in higher oxidation states and prevented their agglomeration and oxidation reduction. The XRD results showed that most Ag in the Ag-EDTA-SBA-15 existed in higher oxidation states such as Ag(II) and Ag(III). However, the XPS and TEM results showed that Ag easily reduced in lower oxidation states and agglomerated as Ag particles on the exterior layer of the SBA-15. PMID:26742050

  16. Synthesis of High Valence Silver-Loaded Mesoporous Silica with Strong Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Chun-Chi Chen

    2016-01-01

    Full Text Available A simple chemical method was developed for preparing high valence silver (Ag-loaded mesoporous silica (Ag-ethylenediaminetetraacetic acid (EDTA-SBA-15, which showed strong antibacterial activity. Ag-EDTA-SBA-15 exhibited stronger and more effective antibacterial activity than commercial Ag nanoparticles did, and it offered high stability of high valence silver in the porous matrix and long-lasting antibacterial activity. The synthesized materials were characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS analysis, and transmission electron microscopy (TEM. Ag existed in both surface complexation and Ag particles. EDTA anchored within a porous structure chelated Ag ions in higher oxidation states and prevented their agglomeration and oxidation reduction. The XRD results showed that most Ag in the Ag-EDTA-SBA-15 existed in higher oxidation states such as Ag(II and Ag(III. However, the XPS and TEM results showed that Ag easily reduced in lower oxidation states and agglomerated as Ag particles on the exterior layer of the SBA-15.

  17. Synthesis of High Valence Silver-Loaded Mesoporous Silica with Strong Antibacterial Properties.

    Science.gov (United States)

    Chen, Chun-Chi; Wu, Hsin-Hsien; Huang, Hsin-Yi; Liu, Chen-Wei; Chen, Yi-Ning

    2016-01-04

    A simple chemical method was developed for preparing high valence silver (Ag)-loaded mesoporous silica (Ag-ethylenediaminetetraacetic acid (EDTA)-SBA-15), which showed strong antibacterial activity. Ag-EDTA-SBA-15 exhibited stronger and more effective antibacterial activity than commercial Ag nanoparticles did, and it offered high stability of high valence silver in the porous matrix and long-lasting antibacterial activity. The synthesized materials were characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) analysis, and transmission electron microscopy (TEM). Ag existed in both surface complexation and Ag particles. EDTA anchored within a porous structure chelated Ag ions in higher oxidation states and prevented their agglomeration and oxidation reduction. The XRD results showed that most Ag in the Ag-EDTA-SBA-15 existed in higher oxidation states such as Ag(II) and Ag(III). However, the XPS and TEM results showed that Ag easily reduced in lower oxidation states and agglomerated as Ag particles on the exterior layer of the SBA-15.

  18. Novel Acoustic Loading of a Mass Spectrometer: Toward Next-Generation High-Throughput MS Screening.

    Science.gov (United States)

    Sinclair, Ian; Stearns, Rick; Pringle, Steven; Wingfield, Jonathan; Datwani, Sammy; Hall, Eric; Ghislain, Luke; Majlof, Lars; Bachman, Martin

    2016-02-01

    High-throughput, direct measurement of substrate-to-product conversion by label-free detection, without the need for engineered substrates or secondary assays, could be considered the "holy grail" of drug discovery screening. Mass spectrometry (MS) has the potential to be part of this ultimate screening solution, but is constrained by the limitations of existing MS sample introduction modes that cannot meet the throughput requirements of high-throughput screening (HTS). Here we report data from a prototype system (Echo-MS) that uses acoustic droplet ejection (ADE) to transfer femtoliter-scale droplets in a rapid, precise, and accurate fashion directly into the MS. The acoustic source can load samples into the MS from a microtiter plate at a rate of up to three samples per second. The resulting MS signal displays a very sharp attack profile and ions are detected within 50 ms of activation of the acoustic transducer. Additionally, we show that the system is capable of generating multiply charged ion species from simple peptides and large proteins. The combination of high speed and low sample volume has significant potential within not only drug discovery, but also other areas of the industry.

  19. Variations in airborne bacterial communities at high altitudes over the Noto Peninsula (Japan in response to Asian dust events

    Directory of Open Access Journals (Sweden)

    T. Maki

    2017-10-01

    Full Text Available Aerosol particles, including airborne microorganisms, are transported through the free troposphere from the Asian continental area to the downwind area in East Asia and can influence climate changes, ecosystem dynamics, and human health. However, the variations present in airborne bacterial communities in the free troposphere over downwind areas are poorly understood, and there are few studies that provide an in-depth examination of the effects of long-range transport of aerosols (natural and anthropogenic particles on bacterial variations. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated and the bacterial variations were compared between dust events and non-dust events.Aerosols were collected at three altitudes from ground level to the free troposphere (upper level: 3000 or 2500 m; middle level: 1200 or 500 m; and low level: 10 m during Asian dust events and non-dust events over the Noto Peninsula, Japan, where westerly winds carry aerosols from the Asian continental areas. During Asian dust events, air masses at high altitudes were transported from the Asian continental area by westerly winds, and laser imaging detection and ranging (lidar data indicated high concentrations of non-spherical particles, suggesting that dust-sand particles were transported from the central desert regions of Asia. The air samples collected during the dust events contained 10–100 times higher concentrations of microscopic fluorescent particles and optical particle counter (OPC measured particles than in non-dust events. The air masses of non-dust events contained lower amounts of dust-sand particles. Additionally, some air samples showed relatively high levels of black carbon, which were likely transported from the Asian continental coasts. Moreover, during the dust events, microbial particles at altitudes of  >  1200 m increased to the concentrations ranging from 1. 2 × 106 to 6

  20. Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment

    Energy Technology Data Exchange (ETDEWEB)

    Celine Cabet; L. Carroll; R. Wright; R. Madland

    2011-05-01

    Alloy 617 is the one of the leading candidate materials for Intermediate Heat eXchangers (IHX) of a Very High Temperature Reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. Furthermore, the anticipated IHX operating temperature, up to 950°C, is in the range of creep so that creep-fatigue interaction, which can significantly increase the fatigue crack growth, may be one of the primary IHX damage modes. To address the needs for Alloy 617 codification and licensing, a significant creep-fatigue testing program is underway at Idaho National Laboratory. Strain controlled LCF tests including hold times up to 1800s at maximum tensile strain were conducted at total strain range of 0.3% and 0.6% in air at 950°C. Creep-fatigue testing was also performed in a simulated VHTR impure helium coolant for selected experimental conditions. The creep-fatigue tests resulted in failure times up to 1000 hrs. Fatigue resistance was significantly decreased when a hold time was added at peak stress and when the total strain was increased. The fracture mode also changed from transgranular to intergranular with introduction of a tensile hold. Changes in the microstructure were methodically characterized. A combined effect of temperature, cyclic and static loading and environment was evidenced in the targeted operating conditions of the IHX. This paper This paper reviews the data previously published by Carroll and co-workers in references 10 and 11 focusing on the role of inelastic strain accumulation and of oxidation in the initiation and propagation of surface fatigue cracks.

  1. Metasurface Reflector (MSR Loading for High Performance Small Microstrip Antenna Design.

    Directory of Open Access Journals (Sweden)

    Md Rezwanul Ahsan

    Full Text Available A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15 is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%, 467 to 606 MHz (29% and 758 MHz to 1062 MHz (40% for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz RFID, WiMAX (3.5/5.5 GHz and WLAN (5.2/5.8 GHz applications.

  2. Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design

    Science.gov (United States)

    Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

    2015-01-01

    A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB) and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz) RFID, WiMAX (3.5/5.5 GHz) and WLAN (5.2/5.8 GHz) applications. PMID:26018795

  3. Aryl Polyenes, a Highly Abundant Class of Bacterial Natural Products, Are Functionally Related to Antioxidative Carotenoids.

    Science.gov (United States)

    Schöner, Tim A; Gassel, Sören; Osawa, Ayako; Tobias, Nicholas J; Okuno, Yukari; Sakakibara, Yui; Shindo, Kazutoshi; Sandmann, Gerhard; Bode, Helge B

    2016-02-02

    Bacterial pigments of the aryl polyene type are structurally similar to the well-known carotenoids with respect to their polyene systems. Their biosynthetic gene cluster is widespread in taxonomically distant bacteria, and four classes of such pigments have been found. Here we report the structure elucidation of the aryl polyene/dialkylresorcinol hybrid pigments of Variovorax paradoxus B4 by HPLC-UV-MS, MALDI-MS and NMR. Furthermore, we show for the first time that this pigment class protects the bacterium from reactive oxygen species, similarly to what is known for carotenoids. An analysis of the distribution of biosynthetic genes for aryl polyenes and carotenoids in bacterial genomes is presented; it shows a complementary distribution of these protective pigments in bacteria.

  4. Low platinum loading for high temperature proton exchange membrane fuel cell developed by ultrasonic spray coating technique

    Science.gov (United States)

    Su, Huaneng; Jao, Ting-Chu; Barron, Olivia; Pollet, Bruno G.; Pasupathi, Sivakumar

    2014-12-01

    This paper reports use of an ultrasonic-spray for producing low Pt loadings membrane electrode assemblies (MEAs) with the catalyst coated substrate (CCS) fabrication technique. The main MEA sub-components (catalyst, membrane and gas diffusion layer (GDL)) are supplied from commercial manufacturers. In this study, high temperature (HT) MEAs with phosphoric acid (PA)-doped poly(2,5-benzimidazole) (AB-PBI) membrane are fabricated and tested under 160 °C, hydrogen and air feed 100 and 250 cc min-1 and ambient pressure conditions. Four different Pt loadings (from 0.138 to 1.208 mg cm-2) are investigated in this study. The experiment data are determined by in-situ electrochemical methods such as polarization curve, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The high Pt loading MEA exhibits higher performance at high voltage operating conditions but lower performances at peak power due to the poor mass transfer. The Pt loading 0.350 mg cm-2 GDE performs the peak power density and peak cathode mass power to 0.339 W cm-2 and 0.967 W mgPt-1, respectively. This work presents impressive cathode mass power and high fuel cell performance for high temperature proton exchange membrane fuel cells (HT-PEMFCs) with low Pt loadings.

  5. Difference in kinematics and kinetics between high- and low-velocity resistance loading equated by volume: implications for hypertrophy training.

    Science.gov (United States)

    Mohamad, Nur Ikhwan; Cronin, John B; Nosaka, Ken K

    2012-01-01

    Although it is generally accepted that a high load is necessary for muscle hypertrophy, it is possible that a low load with a high velocity results in greater kinematics and kinetics than does a high load with a slow velocity. The purpose of this study was to determine if 2 training loads (35 and 70% 1 repetition maximum [1RM]) equated by volume, differed in terms of their session kinematic and kinetic characteristics. Twelve subjects were recruited in this acute randomized within-subject crossover design study. Two bouts of a half-squat exercise were performed 1 week apart, one with high load-low velocity (HLLV = 3 sets of 12 reps at 70% 1RM) and the other with low-load high-velocity (LLHV = 6 sets of 12 reps at 35% 1RM). Time under tension (TUT), average force, peak force (PF), average power (AP), peak power (PP), work (TW), and total impulse (TI) were calculated and compared between loads for the eccentric and concentric phases. For average eccentric and concentric single repetition values, significantly (p eccentric and concentric TUT, PF, AP, PP, and TW. The only variable that was significantly greater for the HLLV protocol than for the LLHV protocol was TI (∼20-24%). From these results, it seems that the LLHV protocol may offer an equal if not better training stimulus for muscular adaptation than the HLLV protocol, because of the greater time under tension, power, force, and work output when the total volume of the exercise is equated.

  6. Viral DNA load of high-risk human papilloma virus is closely associated with the grade of cervical lesions

    OpenAIRE

    Shen, Guqun; Cheng, Jingxin; Wang, Yan; Zhou, Ping; Zhang, Guoqing

    2014-01-01

    This study is to explore the correlation between the viral load of high-risk human papilloma virus (HPV) and the degree of cervical lesions, as well as the follow-up monitoring role of high-risk HPV measurements in the treatment of patients with cervical lesions. Hybrid capture-2 method was used to measure the amount of high-risk HPV load of 361 patients who were enrolled from January 2009 to December 2010 at the Affiliated Tumor Hospital of Xinjiang Medical University, including 76 cases of ...

  7. High Chromium Tolerant Bacterial Strains from Palar River Basin: Impact of Tannery Pollution

    Directory of Open Access Journals (Sweden)

    K. Sundar

    2010-04-01

    Full Text Available The basic survey study on tanneries and its pollution in the Palar river basin of Vellore District showed that it has been contaminated with heavy metals especially chromium and salts. This study is to improve our understanding to find the Cr contamination level and the ecology of heavy metal tolerance of the native bacterial flora of our study area. Chromium tolerant strains were isolated from contaminated sediments, water and effluents of various tanneries. The minimum and maximum concentration of chromium sediments was in the range of 47.4 and 682.4 mg/L, with an average of 306.285 mg/L in the study area. Sixty-eight chromium resistant bacterial strains were isolated and Maximum Tolerance Concentration (MTC studies have indicated that the tolerance concentrations of the isolates were in the range of 100-3300 mg/L. These bacterial isolates were also checked for their resistance to other heavy metals like Ni, Pb, Zn, Fe and Cd. Eighty percent of the isolates showed resistance to Ni, Pb, Zn, Fe at 100 ppm level and 45% had shown resistance to Cd. The isolates also had shown tolerance to salt (NaCl up to 9%. Significant note was found in the concentration of chromium and in the chromium tolerance ability of the bacteria in the study area and these chromium tolerance bacteria can be used as the indicator for the Cr contamination.

  8. Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

    Science.gov (United States)

    Veerapandian, Murugan; Zhang, Linghe; Krishnamoorthy, Karthikeyan; Yun, Kyusik

    2013-10-01

    A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml-1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml-1 for Bacillus subtilis and 0.5 μg ml-1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside.

  9. A NARX damper model for virtual tuning of automotive suspension systems with high-frequency loading

    Science.gov (United States)

    Alghafir, M. N.; Dunne, J. F.

    2012-02-01

    A computationally efficient NARX-type neural network model is developed to characterise highly nonlinear frequency-dependent thermally sensitive hydraulic dampers for use in the virtual tuning of passive suspension systems with high-frequency loading. Three input variables are chosen to account for high-frequency kinematics and temperature variations arising from continuous vehicle operation over non-smooth surfaces such as stone-covered streets, rough or off-road conditions. Two additional input variables are chosen to represent tuneable valve parameters. To assist in the development of the NARX model, a highly accurate but computationally excessive physical damper model [originally proposed by S. Duym and K. Reybrouck, Physical characterization of non-linear shock absorber dynamics, Eur. J. Mech. Eng. M 43(4) (1998), pp. 181-188] is extended to allow for high-frequency input kinematics. Experimental verification of this extended version uses measured damper data obtained from an industrial damper test machine under near-isothermal conditions for fixed valve settings, with input kinematics corresponding to harmonic and random road profiles. The extended model is then used only for simulating data for training and testing the NARX model with specified temperature profiles and different valve parameters, both in isolation and within quarter-car vehicle simulations. A heat generation and dissipation model is also developed and experimentally verified for use within the simulations. Virtual tuning using the quarter-car simulation model then exploits the NARX damper to achieve a compromise between ride and handling under transient thermal conditions with harmonic and random road profiles. For quarter-car simulations, the paper shows that a single tuneable NARX damper makes virtual tuning computationally very attractive.

  10. Effects of Radiation and a High Iron Load on Bone Mineral Density

    Science.gov (United States)

    Yuen, E.; Morgan, J. L. L.; Zwart, S. R.; Gonzales, E.; Camp, K.; Smith, S. M.; Bloomfield, S. A.

    2012-01-01

    Astronauts on long duration space flight missions to the moon or mars are exposed to radiation and have increase iron (Fe) stores, both of which can independently induce oxidative stress and may exacerbate bone mass loss and strength. We hypothesize a high Fe diet and a fractionated gamma radiation exposure would increase oxidative stress and lower bone mass. Three mo-old, SD rats (n=32) were randomized to receive an adequate Fe diet (45 mg Fe/kg diet) or a high Fe diet (650 mg Fe/kg diet) for 4 wks and either a cumulative 3 Gy dose (fractionated 8 x 0.375 Gy) of gamma radiation (Cs-137) or sham exposure starting on day 14. Elisa kit assessed serum catalase, clinical analyzer assessed serum Fe status and ex vivo pQCT scans measured bone parameters in the proximal/midshaft tibia and femoral neck. Mechanical strength was assessed by 3-pt bending and femoral neck test. There is a significant decrease in trabecular bone mineral density (BMD) from radiation (p less than 0.05) and a trend in diet (p=0.05) at the proximal tibia. There is a significant interaction in cortical BMD from the combined treatments at the midshaft tibia (p less than 0.05). There is a trending decrease in total BMD from diet (p=0.07) at the femoral neck. In addition, high serum Fe was correlated to low trabecular BMD (p less than 0.05) and high serum catalase was correlated to low BMD at all 3 bone sites (p less than 0.05). There was no difference in the max load of the tibia or femoral neck. Radiation and a high iron diet increases iron status and catalase in the serum and decreases BMD.

  11. Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

    Science.gov (United States)

    The United States of America as represented by the United States Department of Energy

    2009-12-15

    An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

  12. Effects of acute creatine loading with or without carbohydrate on repeated bouts of maximal swimming in high-performance swimmers.

    Science.gov (United States)

    Theodorou, Apostolos S; Havenetidis, Konstantinos; Zanker, Cathy L; O'Hara, John P; King, Roderick F G J; Hood, Colin; Paradisis, Giorgios; Cooke, Carlton B

    2005-05-01

    The addition of carbohydrate (CHO) to an acute creatine (Cr) loading regimen has been shown to increase muscle total creatine content significantly beyond that achieved through creatine loading alone. However, the potential ergogenic effects of combined Cr and CHO loading have not been assessed. The purpose of this study was to compare swimming performance, assessed as mean swimming velocity over repeated maximal intervals, in high-performance swimmers before and after an acute loading regimen of either creatine alone (Cr) or combined creatine and carbohydrate (Cr + CHO). Ten swimmers (mean +/- SD of age and body mass: 17.8 +/- 1.8 years and 72.3 +/- 6.8 kg, respectively) of international caliber were recruited and were randomized to 1 of 2 groups. Each swimmer ingested five 5 g doses of creatine for 4 days, with the Cr + CHO group also ingesting approximately 100 g of simple CHO 30 minutes after each dose of creatine. Performance was measured on 5 separate occasions: twice at "baseline" (prior to intervention, to assess the repeatability of the performance test), within 48 hours after intervention, and then 2 and 4 weeks later. All subjects swam faster after either dietary loading regimen (p swimmers continued to produce faster swim times for up to 4 weeks after intervention. Our findings suggest that no performance advantage was gained from the addition of carbohydrate to a creatine-loading regimen in these high-caliber swimmers.

  13. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual Load displays: evidence from neglect/extinction

    Directory of Open Access Journals (Sweden)

    Carmel eMevorach

    2014-01-01

    Full Text Available According to perceptual load theory (Lavie, 2005 distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load distractor processing will take place resulting in interference with a primary task; however when target processing uses-up attentional capacity (with high perceptual load interference can be avoided. An alternative account (Tsal & Benoni, 2010 suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  14. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual load displays: evidence from neglect/extinction.

    Science.gov (United States)

    Mevorach, Carmel; Tsal, Yehoshua; Humphreys, Glyn W

    2014-01-10

    According to perceptual load theory (Lavie, 2005) distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load) distractor processing will take place resulting in interference with a primary task; however, when target processing uses-up attentional capacity (with high perceptual load) interference can be avoided. An alternative account (Tsal and Benoni, 2010a) suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high-load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished) field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  15. The characterization of secondary lithium-ion battery degradation when operating complex, ultra-high power pulsed loads

    Science.gov (United States)

    Wong, Derek N.

    The US Navy is actively developing all electric fleets, raising serious questions about what is required of onboard power supplies in order to properly power the ship's electrical systems. This is especially relevant when choosing a viable power source to drive high power propulsion and electric weapon systems in addition to the conventional loads deployed aboard these types of vessels. Especially when high pulsed power loads are supplied, the issue of maintaining power quality becomes important and increasingly complex. Conventionally, a vessel's electrical power is generated using gas turbine or diesel driven motor-generator sets that are very inefficient when they are used outside of their most efficient load condition. What this means is that if the generator is not being utilized continuously at its most efficient load capacity, the quality of the output power may also be effected and fall outside of the acceptable power quality limits imposed through military standards. As a solution to this potential problem, the Navy has proposed using electrochemical storage devices since they are able to buffer conventional generators when the load is operating below the generator's most efficient power level or able to efficiently augment a generator when the load is operating in excess of the generator's most efficient power rating. Specifically, the US Navy is interested in using commercial off-the-shelf (COTS) lithium-ion batteries within an intelligently controlled energy storage module that could act as either a prime power supply for on-board pulsed power systems or as a backup generator to other shipboard power systems. Due to the unique load profile of high-rate pulsed power systems, the implementation of lithium-ion batteries within these complex systems requires them to be operated at very high rates and the effects these things have on cell degradation has been an area of focus. There is very little published research into the effects that high power transient

  16. Absorbing coatings for high power millimeter-wave devices and matched loads

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Bruschi, A.; Cirant, S. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Muzzini, V. [Istituto di Biologia Agro-ambientale e Forestale, Consiglio Nazionale delle Ricerche, Area di Ricerca di Roma 1, Monterotondo, Rome (Italy); Simonetto, A.; Spinicchia, N. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Angella, G. [Istituto per l’Energetica e le Interfasi, Consiglio Nazionale delle Ricerche, Milano (Italy); Dell’Era, F. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Gantenbein, G.; Leonhardt, W. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Nardone, A. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Samartsev, A.; Schmid, M. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2013-10-15

    Highlights: ► An overview of the activity at IFP-CNR concerning the absorbing coatings is presented. ► The application of the absorbing ceramics to the IFP-CNR matched loads is described. ► B{sub 4}C is presented as a promising material for power absorption in the EC frequency range. ► The most important high power validation tests performed on coatings are described. ► Some results from simulations of the absorption capability of a double layer coating are shown. -- Abstract: In the electron cyclotron frequency range the handling of high power is critical. In some cases an unpredictable amount of stray radiation can reach some components or accumulate in localized regions, with risk of damages caused by thermal overloads, and any uncontrolled reflection represents a danger for the sources. A possibility to mitigate the problem consists in covering some regions exposed to radiation with absorbers. Enhanced absorption of stray radiation lowers requirements on active protection systems in microwave diagnostics. The released heat can be extracted by dedicated cooling systems. The chromium oxide (Cr{sub 2}O{sub 3}), largely tested at IFP-CNR, has been routinely used as internal coating for matched loads. The performances of a variable thickness coating has been tested at high power at Karlsruhe Institute of Technology (KIT), with a 140 GHz gyrotron of the W7-X ECRH system and an averaged power density absorbed at the coating surface higher than 1 MW/m{sup 2} for 3 min. Also boron carbide (B{sub 4}C) has been tested at low power and patented as a millimeter-wave absorber. In the paper, the results of some tests performed on these coatings are given, together with some simulations of the absorption capability based on low power measurements on samples. Finally, some calculations are presented for a coating obtained combining together Cr{sub 2}O{sub 3} and B{sub 4}C.

  17. Bed load size distribution and flow conditions in a high mountain catchment of Central Pyrenees

    Directory of Open Access Journals (Sweden)

    Martínez-Castroviejo, Ricardo

    1990-06-01

    Full Text Available The bed load size distribution caused by different types of flow are compared in a high mountain catchment located in the upper Gallego river basin (Central Spanish’ Pyrenees. Three kinds of hydrologic events could be defined: those triggered by heavy autumn rainfalls, those originated by isolated summer rainstorms and those promoted by snowmelting. Each one is characterized by a peculiar bed load size distribution. Thus, it could be demonstrated that the coarser fractions, above 30 mm in diameter, are up to six times more abundant, in percentage of total weight, in transports caused by heavy rainfalls than in the material collected after snowmelt flows. In its turn, bed load mobilized by snowmelt flows is mainly composed by medium and fine gravel, from 2 to 8 mm. These may amount up to 60 % of total weight of bed load. The reasons for these so different size distributions are discussed.

    [es] En una cuenca de alta montaña localizada en el alto valle del río Gallego (Pirineo central se comparan las distribuciones por tamaños de los acarreos movilizados por diferentes tipos de caudal. Tres tipos de eventos hidrológicos han podido ser caracterizados: los ocasionados por intensas lluvias de otoño, los originados por tormentas estivales aisladas y los producidos por la fusión de la nieve acumulada durante el invierno. Se concluye que cada uno de ellos lleva asociada una distribución por tamaños típica de la carga de fondo. Así, se ha comprobado que las fracciones más gruesas consideradas -superiores a los 30 mm de diámetro- son hasta seis veces más abundantes -en porcentaje sobre el peso total- en las exportaciones causadas por lluvias de gran intensidad que en las generadas por caudales de fusión. A su vez, las descargas ocasionadas por la fusión arrastran principalmente gravas de calibre medio y fino -entre 2y8 mm- que llegan a suponer el 60 % en peso del volumen movilizado. Este artículo discute las razones que provocan

  18. Francis-99: Transient CFD simulation of load changes and turbine shutdown in a model sized high-head Francis turbine

    Science.gov (United States)

    Mössinger, Peter; Jester-Zürker, Roland; Jung, Alexander

    2017-01-01

    With increasing requirements for hydropower plant operation due to intermittent renewable energy sources like wind and solar, numerical simulations of transient operations in hydraulic turbo machines become more important. As a continuation of the work performed for the first workshop which covered three steady operating conditions, in the present paper load changes and a shutdown procedure are investigated. The findings of previous studies are used to create a 360° model and compare measurements with simulation results for the operating points part load, high load and best efficiency. A mesh motion procedure is introduced, allowing to represent moving guide vanes for load changes from best efficiency to part load and high load. Additionally an automated re-mesh procedure is added for turbine shutdown to ensure reliable mesh quality during guide vane closing. All three transient operations are compared to PIV velocity measurements in the draft tube and pressure signals in the vaneless space. Simulation results of axial velocity distributions for all three steady operation points, during both load changes and for the shutdown correlated well with the measurement. An offset at vaneless space pressure is found to be a result of guide vane corrections for the simulation to ensure similar velocity fields. Short-time Fourier transformation indicating increasing amplitudes and frequencies at speed-no load conditions. Further studies will discuss the already measured start-up procedure and investigate the necessity to consider the hydraulic system dynamics upstream of the turbine by means of a 1D3D coupling between the 3D flow field and a 1D system model.

  19. Demonstration of sulfur solubility determinations in high waste loading, low-activity waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-25

    A method recommended by Pacific Northwest National Laboratory (PNNL) for sulfate solubility determinations in simulated low-activity waste glasses was demonstrated using three compositions from a recent Hanford high waste loading glass study. Sodium and sulfate concentrations in the glasses increased after each re-melting step. Visual observations of the glasses during the re-melting process reflected the changes in composition. The measured compositions showed that the glasses met the targeted values. The amount of SO3 retained in the glasses after washing was relatively high, ranging from 1.6 to 2.6 weight percent (wt %). Measured SnO2 concentrations were notably low in all of the study glasses. The composition of the wash solutions should be measured in future work to determine whether SnO2 is present with the excess sulfate washed from the glass. Increases in batch size and the amount of sodium sulfate added did not have a measureable impact on the amount of sulfate retained in the glass, although this was tested for only a single glass composition. A batch size of 250 g and a sodium sulfate addition targeting 7 wt %, as recommended by PNNL, will be used in future experiments.

  20. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Directory of Open Access Journals (Sweden)

    Weihua Xie

    2016-10-01

    Full Text Available This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs, which are equipped with chemical composition gratings sensors (CCGs. The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C.

  1. Microstructural and Chemical Characterization of the Tribolayer Formation in Highly Loaded Cylindrical Roller Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Carsten Gachot

    2016-06-01

    Full Text Available Zinc dithiophosphates (ZDDP have been widely applied in automobile industry for over 70 years as a lubricant additive for wear protection. Tribolayers have been described as blue- and brown-colored layers on surfaces observed by microscopical observation or even bare eye presumably as a consequence of layer thickness or chemical composition. However, the reaction pathways of ZDDP tribolayers are still not yet fully understood. In the present study, the difference between the blue- and brown-colored tribolayers has been revealed by high resolution methods in cylindrical roller thrust bearings at relatively high contact pressures of around 1.92 GPa. After running a FE8 standard bearing test with a normal load of 80 kN and a temperature of 60 °C, said tribolayers could be identified on the bearing surfaces. By using Raman spectroscopy, it could be shown that the blue-colored layers are enriched by FeS and ZnS whereas the brown-colored layers show a significant amount of Fe3O4. This is an interesting finding as it clearly shows a correlation between the color appearance of the films and the chemical composition besides potential film thickness variations. Finally, transmission electron microscopy verified the amorphous nature of the formed tribolayer which is in a good agreement with literature.

  2. Characterization of ITER tungsten qualification mock-ups exposed to high cyclic thermal loads

    Energy Technology Data Exchange (ETDEWEB)

    Pintsuk, Gerald, E-mail: g.pintsuk@fz-juelich.de [Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Bednarek, Maja; Gavila, Pierre [Fusion for Energy, E-08019 Barcelona (Spain); Gerzoskovitz, Stefan [Plansee SE, Innovation Services, 6600 Reutte (Austria); Linke, Jochen [Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Lorenzetto, Patrick; Riccardi, Bruno [Fusion for Energy, E-08019 Barcelona (Spain); Escourbiac, Frederic [ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 Saint Paul lez Durance (France)

    2015-10-15

    Highlights: • Mechanical deformation of CuCrZr in case a thermal barrier layer has been formed due to impurity content in the cooling water. • Crack formation at the W/Cu interface starting at the block edge. • Porosity formation in the pure Cu interlayer. • Microstructural changes in tungsten down to the W/Cu interface, which indicates also high temperatures for the pure Cu interlayer. • Macrocrack formation in tungsten which is assumed to be ductile at the initiation point and brittle when proceeding toward the cooling tube. - Abstract: High heat flux tested small-scale tungsten monoblock mock-ups (5000 cycles at 10 MW/m{sup 2} and up to 1000 cycles at 20 MW/m{sup 2}) manufactured by Plansee and Ansaldo were characterized by metallographic means. Therein, the macrocrack formation and propagation in tungsten, its recrystallization behavior and the surface response to different heat load facilities were investigated. Furthermore, debonding at the W/Cu interface, void formation in the soft copper interlayer and microcrack formation at the inner surface of the CuCrZr cooling tube were found.

  3. MORPHOLOGY AND PROPERTIES OF LINEAR LOW-DENSITY POLYETHYLENE HIGHLY LOADED WITH ALUMINUM HYDROXIDE

    Institute of Scientific and Technical Information of China (English)

    Gen-lin Wang; Ping-kai Jiang; Zi-kang Zhu; Jie Yin

    2002-01-01

    An experimental study was carried out to investigate the effects of isopropoxy tri(dioctyl pyrophosphoryl) titanate coupling agent on the mechanical performance, rheological property and microstructures of polyethylene highly loaded with aluminum hydroxide (Al(OH)a) composite. It was found that the addition of coupling agent results in reduced tensile strength and increased percentage elongation of the filled systems. Silane crosslinkable polyethylene substituting for polyethylene as matrix improves the tensile strength of the composite, while the percentage elongation of the composite still remains at a desired level. Melt viscosity of the composite will be improved by addition of titanate coupling agent. Microstructures of the composites were also studied by means of the scanning electron microscopy (SEM) technique. SEM micrographs reveal that finer dispersion of Al(OH)3 will be obtained upon treatment of titanate and a transition from brittle to tough fracture takes place before and after silane crosslinking structure is introduced into polyethylene highly filled with Al(OH)3 composite.

  4. The effect of high intensity ultrasound on the loading of Au nanoparticles into titanium dioxide.

    Science.gov (United States)

    Belova, Valentina; Borodina, Tatiana; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-01-01

    Novel metal/semiconductor nanocomposites have been synthesized from pre-formed components by applying high intensity ultrasound irradiation. Positively and negatively charged Au nanoparticles were intercalated into mesoporous TiO(2) by sonication. The synthesized nanocomposites with implanted gold nanoparticles possess a narrow pore-size distribution around 7 nm and a large surface area of about 210 m(2)/g. The intercalation of the Au nanoparticles into the TiO(2) framework depends on the charge of the Au nanoparticles, time and amplitude of ultrasonic treatment. The experiments show that at 20 min of ultrasonic irradiation the volume fraction of the negatively charged Au nanoparticles intercalated into TiO(2) is 15%. By contrast, at the same time, 8.1% of positively charged Au nanoparticles with a diameter of about 6-7 nm enters into the TiO(2) matrix. The characterization of the samples was carried out by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared measurements and BET analysis. The structure of TiO(2) was not considerably affected by the intercalation of the Au nanoparticles. TiO(2) doped with negatively charged Au nanoparticles presented a higher photocatalytic activity (75 wt.%) than TiO(2) loaded with positively charged Au nanoparticles (62 wt.%), because of an enlarged surface area and quantity of Au nanoparticles in titania. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. High-speed motion picture camera experiments of cavitation in dynamically loaded journal bearings

    Science.gov (United States)

    Hamrock, B. J.; Jacobson, B. O.

    1983-01-01

    A high-speed camera was used to investigate cavitation in dynamically loaded journal bearings. The length-diameter ratio of the bearing, the speeds of the shaft and bearing, the surface material of the shaft, and the static and dynamic eccentricity of the bearing were varied. The results reveal not only the appearance of gas cavitation, but also the development of previously unsuspected vapor cavitation. It was found that gas cavitation increases with time until, after many hundreds of pressure cycles, there is a constant amount of gas kept in the cavitation zone of the bearing. The gas can have pressures of many times the atmospheric pressure. Vapor cavitation bubbles, on the other hand, collapse at pressures lower than the atmospheric pressure and cannot be transported through a high-pressure zone, nor does the amount of vapor cavitation in a bearing increase with time. Analysis is given to support the experimental findings for both gas and vapor cavitation. Previously announced in STAR as N82-20543

  6. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Science.gov (United States)

    Xie, Weihua; Meng, Songhe; Jin, Hua; Du, Chong; Wang, Libin; Peng, Tao; Scarpa, Fabrizio; Xu, Chenghai

    2016-01-01

    This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs), which are equipped with chemical composition gratings sensors (CCGs). The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE) model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C. PMID:27754356

  7. The Combined Effect of Electrical Stimulation and High-Load Isometric Contraction on Protein Degradation Pathways in Muscle Atrophy Induced by Hindlimb Unloading

    OpenAIRE

    Naoto Fujita; Shinichiro Murakami; Hidemi Fujino

    2011-01-01

    High-load isometric exercise is considered an effective countermeasure against muscle atrophy, but therapeutic electrical stimulation for muscle atrophy is often performed without loading. In the present study, we investigated the combined effectiveness of electrical stimulation and high-load isometric contraction in preventing muscle atrophy induced by hindlimb unloading. Electrical stimulation without loading resulted in slight attenuation of muscle atrophy. Moreover, combining electrical s...

  8. High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    Science.gov (United States)

    Shimer, Daniel W.; Lange, Arnold C.

    1995-01-01

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  9. Systems biology of bacterial nitrogen fixation: High-throughput technology and its integrative description with constraint-based modeling

    Directory of Open Access Journals (Sweden)

    Resendis-Antonio Osbaldo

    2011-07-01

    Full Text Available Abstract Background Bacterial nitrogen fixation is the biological process by which atmospheric nitrogen is uptaken by bacteroids located in plant root nodules and converted into ammonium through the enzymatic activity of nitrogenase. In practice, this biological process serves as a natural form of fertilization and its optimization has significant implications in sustainable agricultural programs. Currently, the advent of high-throughput technology supplies with valuable data that contribute to understanding the metabolic activity during bacterial nitrogen fixation. This undertaking is not trivial, and the development of computational methods useful in accomplishing an integrative, descriptive and predictive framework is a crucial issue to decoding the principles that regulated the metabolic activity of this biological process. Results In this work we present a systems biology description of the metabolic activity in bacterial nitrogen fixation. This was accomplished by an integrative analysis involving high-throughput data and constraint-based modeling to characterize the metabolic activity in Rhizobium etli bacteroids located at the root nodules of Phaseolus vulgaris (bean plant. Proteome and transcriptome technologies led us to identify 415 proteins and 689 up-regulated genes that orchestrate this biological process. Taking into account these data, we: 1 extended the metabolic reconstruction reported for R. etli; 2 simulated the metabolic activity during symbiotic nitrogen fixation; and 3 evaluated the in silico results in terms of bacteria phenotype. Notably, constraint-based modeling simulated nitrogen fixation activity in such a way that 76.83% of the enzymes and 69.48% of the genes were experimentally justified. Finally, to further assess the predictive scope of the computational model, gene deletion analysis was carried out on nine metabolic enzymes. Our model concluded that an altered metabolic activity on these enzymes induced

  10. Pilot study to evaluate 3 hygiene protocols on the reduction of bacterial load on the hands of veterinary staff performing routine equine physical examinations

    OpenAIRE

    Josie L Traub-Dargatz; Weese, J Scott; Rousseau, Joyce D.; Dunowska, Magdalena; Morley, Paul S.; Dargatz, David A.

    2006-01-01

    Reduction factors (RFs) for bacterial counts on examiners’ hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl ...

  11. Tribological Evaluation of Candidate Gear Materials Operating Under Light Loads in Highly Humid Conditions

    Science.gov (United States)

    Dellacorte, Christopher; Thomas, Fransua; Leak, Olivia Ann

    2015-01-01

    A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9 N, 2.7 m/s) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (approx. 0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via the secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed

  12. Mycoplasma, bacterial vaginosis-associated bacteria BVAB3, race, and risk of preterm birth in a high-risk cohort.

    Science.gov (United States)

    Foxman, Betsy; Wen, Ai; Srinivasan, Usha; Goldberg, Deborah; Marrs, Carl F; Owen, John; Wing, Deborah A; Misra, Dawn

    2014-03-01

    Genital tract infection accounts for approximately 25-40% of all preterm births. We sought to assess the relationship between preterm birth and selected vaginal bacterial taxa associated with preterm birth either directly or through their association with bacterial vaginosis (BV). Vaginal fluid for Gram stain was collected between 17 and 22 weeks' gestation as part of a randomized trial of ultrasound-indicated cerclage for preterm birth prevention in women at high risk for recurrent spontaneous preterm birth. Bacterial deoxyribonucleic acid was extracted from the Gram stain slides and analyzed using quantitative polymerase chain reaction. Among the 499 participants, Mycoplasma was positively correlated with increased risk of preterm (risk ratio [RR], 1.83; 95% confidence interval [CI], 1.52-2.22) as was Mobiluncus (RR, 1.36; 95% CI, 1.07-1.73) and Atopobium (RR, 1.44; 95% CI, 1.1-1.87). However, there were strong interactions between the race/ethnic group and the presence of these and other individual taxa on risk of preterm birth. By contrast, bacterial vaginosis-associated bacteria (BVAB)-3 was consistently associated with a reduction in the risk of preterm birth for all racial/ethnic groups (0.55; 95% CI, 0.39-0.78). BV is characterized by a reduction of Lactobacillus, and lactic acid-producing bacteria and the presence of Mobiluncus; we found these factors and the presence of Mycoplasma to be associated with an increased risk of preterm birth. By contrast, the presence of a recently identified organism sufficient to cause BV, BVAB3, decreased the risk of preterm birth. These findings give insight into why treating BV has mixed impact on risk of preterm birth. Copyright © 2014 Mosby, Inc. All rights reserved.

  13. Lowering the platinum loading of high temperature polymer electrolyte membrane fuel cells with acid doped polybenzimidazole membranes

    DEFF Research Database (Denmark)

    Fernandez, Santiago Martin; Li, Qingfeng; Jensen, Jens Oluf

    2015-01-01

    Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was establ......Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer...

  14. Dry coating of micronized API powders for improved dissolution of directly compacted tablets with high drug loading.

    Science.gov (United States)

    Han, Xi; Ghoroi, Chinmay; Davé, Rajesh

    2013-02-14

    Motivated by our recent study showing improved flow and dissolution rate of the active pharmaceutical ingredient (API) powders (20 μm) produced via simultaneous micronization and surface modification through continuous fluid energy milling (FEM) process, the performance of blends and direct compacted tablets with high drug loading is examined. Performance of 50 μm API powders dry coated without micronization is also considered for comparison. Blends of micronized, non-micronized, dry coated or uncoated API powders at 30, 60 and 70% drug loading, are examined. The results show that the blends containing dry coated API powders, even micronized ones, have excellent flowability and high bulk density compared to the blends containing uncoated API, which are required for direct compaction. As the drug loading increases, the difference between dry coated and uncoated blends is more pronounced, as seen in the proposed bulk density-FFC phase map. Dry coating led to improved tablet compactibility profiles, corresponding with the improvements in blend compressibility. The most significant advantage is in tablet dissolution where for all drug loadings, the t(80) for the tablets with dry coated APIs was well under 5 min, indicating that this approach can produce nearly instant release direct compacted tablets at high drug loadings.

  15. Ethanol Production from High Solids Loading of Alkali-Pretreated Sugarcane Bagasse with an SSF Process

    Directory of Open Access Journals (Sweden)

    Yueshu Gao

    2014-04-01

    Full Text Available A fed-batch process and high-temperature simultaneous saccharification and fermentation (SSF process were investigated to obtain high sugar yield and ethanol concentration. Different amounts of alkali-pretreated sugarcane bagasse were added during the first 24 h. For the highest final dry matter (DM content of 25% (w/v, a maximal glucose and total sugar concentration of 79.53 g/L and 135.39 g/L, respectively, were achieved with 8.3 FPU/g substrate after 120 h of hydrolysis. Based on the hydrolysis experiment, two processes for ethanol production from sugarcane bagasse, simultaneous saccharification and fermentation (SSF and separate hydrolysis and fermentation (SHF, were also compared using S. cerevisiae. The results indicated that ethanol concentration and yield in the SHF were higher, while ethanol productivity (gram per unit volume and over time was lower. For 25% substrate loading, the ethanol productivity and ethanol concentration could reach 0.38 g.L-1.h-1 and 36.25 g/L SSF in 96 h, respectively, while that of SHF could reach 0.32 g.L-1.h-1, with an ethanol concentration of 47.95 g/L in 152 h for SHF. When high-temperature simultaneous saccharification and fermentation (SSF process was performed by using Kluyveromyces marxianus NCYC 587 at 42 °C, 42.21 g/L ethanol (with an ethanol productivity of 0.44 g.L-1.h-1 was produced with 25% dry matter content and 8.3 FPU cellulase/g substrate, which meant 16.4% more ethanol when compared with SSF of S. cerevisiae.

  16. RELATIONSHIP BETWEEN BLOOD LACTATE AND HYPERVENTILATION DURING HIGH-INTENSITY CONSTANT-LOAD EXERCISE IN HEAT

    Directory of Open Access Journals (Sweden)

    T. Chiba

    2011-09-01

    Full Text Available The purpose of this study was to examine the relationship between hyperventilation and increase in blood lactate during high-intensity constant-load exercise in heat and normal conditions. Seven male volunteers exercised for 10 min on a cycle ergometer at 80%·VO2max in heat (40ºC, 50%relative humidity: HT and normal conditions (20ºC, 50% relative humidity: CON. Oxygen uptake, carbon dioxide output, ventilation, blood lactate and blood electrolytes (K , Na , Cl− were measured in HT and CON. We found that ventilation was significantly higher during exercise in HT compared with CON (p<0.05 and RER tends to be higher in HT than in CON. Blood lactate was significantly higher at 3 min during exercise in HT compared with CON (5.96 ± 0.57 mEq·l-1 5.00 ± 0.28 mEq·l-1, p<0.05. Change in strong ion difference [∆SID = (∆K ∆Na − (∆Cl− ∆La−], which affects ∆HCO3− in blood significantly, was lower at 5 min during exercise in HT compared with in CON (p<0.05. These results suggest that hyperventilation during exercise in heat would induce lower HCO3− in blood and consequently would result in an increase in blood lactate at an earlier time during high-intensity exercise in heat. It was concluded that hyperventilation during short-term high-intensity exercise in heat is temporarily associated with an increase in blood lactate.

  17. Lateral Load-Resisting System Using Mass Timber Panel for High-Rise Buildings

    Directory of Open Access Journals (Sweden)

    Zhiyong Chen

    2017-07-01

    Full Text Available As global interest in using engineered wood products in tall buildings intensifies due to the “green” credential of wood, it is expected that more tall wood buildings will be designed and constructed in the coming years. This, however, brings new challenges to the designers. One of the major challenges is how to design lateral load-resisting systems (LLRSs with sufficient stiffness, strength, and ductility to resist strong wind and earthquakes. In this study, an LLRS using mass timber panel on a stiff podium was developed for high-rise buildings in accordance with capacity-based design principle. The LLRS comprises eight shear walls with a core in the center of the building, which was constructed with structural composite lumber and connected with dowel-type connections and wood–steel composite system. The main energy dissipating mechanism of the LLRS was detailed to be located at the panel-to-panel interface. This LLRS was implemented in the design of a hypothetical 20-storey building. A finite element (FE model of the building was developed using general-purpose FE software, ABAQUS. The wind-induced and seismic response of the building model was investigated by performing linear static and non-linear dynamic analyses. The analysis results showed that the proposed LLRS using mass timber was suitable for high-rise buildings. This study provided a valuable insight into the structural performance of LLRS constructed with mass timber panels as a viable option to steel and concrete for high-rise buildings.

  18. Evaluation of drug loading capabilities of γ-cyclodextrin-metal organic frameworks by high performance liquid chromatography.

    Science.gov (United States)

    Xu, Xiaonan; Wang, Caifen; Li, Haiyan; Li, Xue; Liu, Botao; Singh, Vikramjeet; Wang, Shuxia; Sun, Lixin; Gref, Ruxandra; Zhang, Jiwen

    2017-03-10

    Drug loading into γ-cyclodextrin-metal organic frameworks (γ-CD-MOFs) using the impregnation approach is a laborious process. In this study, a γ-CD-MOF construct (2-5μm particle diameter) was used as the stationary phase under HPLC conditions with the aim to correlate retention properties and drug loading capability of the CD-based structure. Ketoprofen, fenbufen and diazepam were chosen as model drugs with m-xylene as a control analyte to investigate the correlation of drug loading and their chromatographic behaviour in the γ-CD-MOF column. Furthermore, γ-CD itself was also prepared as the stationary phase by coupling with silica in the column to illustrate the enhanced interaction between drugs and γ-CD-MOF as a reference. The retention and loading efficiency of the drugs were determined with different ratios of hexane and ethanol (10:90, 20:80, 50:50, 80:20, 90:10, v/v) at temperatures of 20, 25, 30 and 37°C. With the increment in hexane content, the loading efficiency of ketoprofen and fenbufen increased from 2.39±0.06% to 4.38±0.04% and from 5.82±0.94% to 6.37±0.29%, respectively. The retention time and loading efficiency of ketoprofen and diazepam were the lowest at 30°C while those of fenbufen had the different tendency. The excellent relation between the retention and loading efficiency onto γ-CD-MOF could be clearly observed through mobile phase and temperature investigation. In conclusion, a highly efficient chromatographic method has been established to evaluate the drug loading capability of γ-CD-MOF.

  19. Scan-directed load balancing for highly-parallel mesh-connected computers. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Biagioni, E.S.; Prins, J.F.

    1991-07-01

    Scan Directed Load Balancing is a new, locality-preserving, dynamic load balancing algorithm for grid based computations on mesh connected parallel computers. Scans are used to efficiently determine what areas of the machine are heavily loaded and what areas are lightly loaded, and to organize the movement of data. Data is shifted along the mesh in a regular fashion to balance the load. The Locality Property of the algorithm guarantees that all the neighbors of a data point on the grid are stored either on the same processor, or on a processor that is directly connected to it. Scan Directed Load Balancing is applicable to both SIMD and MIMD mesh-connected parallel computers, and has been implemented on the MasPar MP-1. The authors present some theoretical bounds achieved by the algorithm as well as the algorithm's performance on a particular image processing problem, edge-directed diffusion. Their experiments show that the algorithm is effective in improving the load distribution for real problems, while the efficiency of the original grid-based computation is preserved by the locality property.

  20. Optimization of {beta}-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, Michael D., E-mail: triplettm@battelle.or [Battelle Memorial Institute, Health and Life Sciences Global Business (United States); Rathman, James F. [The Ohio State University, Department of Chemical and Biomolecular Engineering (United States)

    2009-04-15

    Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, {beta}-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of {beta}-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. {beta}-Carotene entrapment efficiency averaged 40%. {beta}-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

  1. Flaw assessment guide for high-temperature reactor components subject to creep-fatigue loading

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, R.A. (Nuclear Electric PLC, Berkeley (UK). Berkeley Nuclear Labs.); Ruggles, M.B. (Oak Ridge National Lab., TN (USA)); Takahashi, Y. (Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.)

    1990-10-01

    A high-temperature flaw assessment procedure is described. This procedure is a result of a collaborative effort between Electric Power Research Institute in the United States, Central Research Institute of Electric Power Industry in Japan, and Nuclear Electric plc in the United Kingdom. The procedure addresses preexisting defects subject to creep-fatigue loading conditions. Laws employed to calculate the crack growth per cycle are defined in terms of fracture mechanics parameters and constants related to the component material. The crack-growth laws can be integrated to calculate the remaining life of a component or to predict the amount of crack extension in a given period. Fatigue and creep crack growth per cycle are calculated separately, and the total crack extension is taken as the simple sum of the two contributions. An interaction between the two propagation modes is accounted for in the material properties in the separate calculations. In producing the procedure, limitations of the approach have been identified. 25 refs., 1 fig.

  2. Bearing Capacity of High Density Polyethylene (HDPE Reinforced Sand Using Plate Load Test

    Directory of Open Access Journals (Sweden)

    Er. Aly K

    2015-06-01

    Full Text Available The work presented here is a study to examine the improvement in bearing capacity of coastal sand of Trivandrum, Kerala, India using high density polyethylene (HDPE /woven fabric as reinforcement in discrete layers. The bearing capacity was evaluated using plate load test. The effect of reinforcement configurations like sheet reinforcement (sanded with adhesive, with adhesive and sheet alone and strip reinforcement (single and grid pattern are investigated. The test parameters chosen for the present study are, depth of topmost layer of reinforcement layer below footing, compacted density and number of layers of reinforcement etc. From the tests, it has been observed that sheet reinforcement is more effective than sheet sanded with adhesive and strip reinforcements. It is found that the synthetic adhesive gives no binding action at the interface of the reinforcement and soil. But it is to be noted that the sheet with adhesive dried has a marked influence on the bearing capacity especially at lower densities. The strip reinforcements in single pattern is considered to be a favorable choice for minimum reinforcement. The strip reinforcement in single or grid pattern gives sufficient improvement in strength.

  3. Investigation of vacuum properties of CuCrZr alloy for high-heat-load absorber

    Science.gov (United States)

    Shueh, C.; Chan, C. K.; Chang, C. C.; Sheng, I. C.

    2017-01-01

    The Taiwan Photon Source (TPS) uses high-heat-load (HHL) absorbers to protect downstream ultrahigh-vacuum chambers from overheating. In this work, we propose to use the CuCrZr alloy (ASTM C18150) for the HHL absorber body and the ConFlat flanges. We use the throughput method to measure the thermal outgassing rate and a helium leak detector to verify the vacuum seal between the CuCrZr alloy and stainless-steel flanges. The measured outgassing rate of the CuCrZr alloy was 5.8×10-10 Pa m/s after 72 h of pumping and decreased to 2.0 × 10-10 Pa m/s after 100 h of pumping. The leak rate through the vacuum seal between a CuCrZr flange and a stainless-steel flange was less than 1 × 10-10 Pa m3/s even after mounting and unmounting the flanges ten times and baking them at 250 °C. These results indicate that CuCrZr alloy is suitable for integrating HHL components with ConFlat CuCrZr flanges for the absorption of the synchrotron radiation generated by the TPS.

  4. Biomass accumulation modelling in a highly loaded biotrickling filter for hydrogen sulphide removal.

    Science.gov (United States)

    Mannucci, Alberto; Munz, Giulio; Mori, Gualtiero; Lubello, Claudio

    2012-07-01

    A pilot scale test on a biotrickling filter packed with polyurethane foam cubes was carried out for 110 d at high volumetric mass load (up to 280 g m(bed)(-3) h(-1)) with the aim of studying the accumulation of solids in the treatment of H(2)S. Removal rate up to 245 g m(bed)(-3) h(-1) was obtained; however, an accumulation of gypsum, elemental sulphur and, above all, inert biomass was identified as the cause of an increased pressure drop over the long term. A mathematical model was applied and calibrated with the experimental results to describe the accumulation of biomass. The model was capable of describing the accumulation of solids and, corresponding to a solids retention time of 50 d, the observed yield resulted in 0.07 g of solids produced g(-1) H(2)S removed. Respirometric tests showed that heterotrophic activity is inhibited at low pH (pH < 2.3), and the contribution to biomass removal through decay was negligible.

  5. Biosyngas Fischer. Tropsch conversion by high Fe loaded supported catalysts prepared with ultrasound and microwave

    Energy Technology Data Exchange (ETDEWEB)

    Pirola, C.; Di Fronzo, A.; Boffito, D.C.; Bianchi, C. [Milano Univ. (Italy). Dipt. di Chimica; Di Michele, A. [Perugia Univ. (Italy). Dipt. di Fisica

    2012-07-01

    Catalysts with iron high loading