368 research outputs found

    Coherent Phonons in Bismuth Film Observed by Ultrafast Electron Diffraction

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    The generation of coherent phonons in polycrystalline bismuth film excited with femtosecond laser pulse is observed by ultrafast time-resolved electron diffraction. The dynamics of the diffracted intensities from the (110), (202), and (024) lattice planes show pronounced oscillations at 130-150 GHz. The origin of these coherent acoustic phonons is discussed in view of optical phonon decay into two acoustic phonons. Different drop times in the intensity of the diffraction orders are observed and interpreted as anisotropy in the energy transfer rate of coherent optical phonons

    Improving high-altitude UV–Vis resistance of PBO braided tendons of NASA’s super pressure balloons

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    Super pressure balloons (SPBs) are used by the National Aeronautics and Space Administration (NASA) for ultra-long duration ballooning (ULDB) missions which carry various scientific explorations to support space and earth sciences research activities. The resistance to photo-degradation of load-bearing braided tendons of SPBs is critical to the success of ULDB missions. Recognizing the critical need to improve UV and visible light (UV–Vis) protective performance of p-phenylene-2, 6-benzobisoxazole (PBO) braids, North Carolina State University and NASA’s Balloon Program collaborated to investigate the effectiveness of sheath extrusion method in improving the UV–Vis resistance of tendons. This study included two PBO tendon types – 48,000 (48k) denier tendons and 72,000 (72k) denier tendons. Using a sheath extrusion method, the tendons were covered with UV protective sheath of low-density polyethylene containing two types of UV inhibitors – TiO2 rutile nanoparticles and PolyOne PE White CC®. Bare and sheathed tendons were subjected to artificial UVB exposure in the lab as well as to both high altitude and ground exposure during flight missions conducted by NASA. Protection against radiation exposure was evaluated by determining the loss of tensile strength after exposure. UV–Vis protection of tendons improved with an increase in sheath thickness as well as UV inhibitor content in the sheath. The results also showed that 72k denier braids had higher resistance against UV degradation compared to 48k denier braids. In-flight exposure results confirmed the comparative UV protective performance of tendons exposed to accelerated artificial UVB exposure in lab. 72k denier tendon covered with sheath containing 10% PE White CC® (sheath thickness of 0.37 mm) experienced the lowest strength loss among all tendon samples to high-altitude exposure during flight missions. The study has also utilized UV–Vis transmittance of the sheath covering the braids as a method of evaluating the performance of the protective sheaths

    Sinteza i protuupalno, analgetsko i ulcerogeno djelovanje derivata tieno[2,3-d]pirimidina

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    5-Methyl-6-phenyl-2-thioxothieno[2,3-d]pyrimidone derivative (2) reacted with hydrazonoyl chloride derivatives to afford triazolothienopyrimidones 4a-f. Also, acetone-1-(2-amino-5-isopropyl-thiophene-3-carbonitrile) (3) reacted with functional and bifunctional groups to yield the corresponding compounds 5-11. The new products showed anti-inflammatory, analgesic, and ulcerogenic activities comparable to that of indomethacin and acetylsalicylic acid, respectively.Reakcijom derivata 5-metil-6-fenil-2-tioksotieno[2,3-d]pirimidona (2) s hidrazonoil kloridima dobiveni su triazolotienopirimidoni 4a-f, a reakcijom aceton-1-(2-amino-5-izopropil-tiopen-3-karbonitrila (3) s funkcionalnim i bifunkcionalnim spojevima dobiveni su produkti 511. Novi spojevi imaju slično protuupalno, analgetsko i ulcerogeno djelovanje kao i indometacin, odnosno acetilsalicilna kiselina

    DIVERSITY OF BACILLUS GENOTYPES IN SOIL SAMPLES FROM EL-OMAYED BIOSPHERE RESERVE IN EGYPT

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    Sequencing of the 16S rDNA hypervariant region was applied to determine the presence and composition of Bacillus species in 40 soil samples randomly collected from different habitats in El-Omayed biosphere reserve, Egypt. Although purified cultures showed 18 different phenotypes that were morphologically distinct on a sporulation medium plate, only 4 different nucleotide sequences designated Seq A, B, C and D were revealed. Computational analysis of DNA sequence data suggested that 17 of these isolates are closely related members of the Bacillus cereus/thuringiensis group (Seq B, C and D) and one isolate is belonging to the Bacillus subtilis group (Seq A). Further phenotypic investigations confirmed the diversity of the 17 novel Bacillus cereus/thuringiensis isolates and indicated that the new Bacillus subtilis group isolate is a Bacillus amyloliquefaciens strain. A simple phenotypic discrimination key that can be applied for distinguishing between such closely related Bacillus cereus/thuringiensis members is presented

    Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads

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    Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria

    Female urgency, trial of urodynamics as routine evaluation (FUTURE study): A superiority randomised clinical trial to evaluate the effectiveness and cost-effectiveness of invasive urodynamic investigations in management of women with refractory overactive

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    Background: Overactive bladder (OAB) syndrome is a symptom complex affecting 12–14% of the UK adult female population. Symptoms include urinary urgency, with or without urgency incontinence, increased daytime urinary frequency and nocturia. OAB has a negative impact on women’s social, physical, and psychological wellbeing. Initial treatment includes lifestyle modifications, bladder retraining, pelvic floor exercises and pharmacological therapy. However, these measures are unsuccessful in 25–40% of women (refractory OAB). Before considering invasive treatments, such as Botulinum toxin injection or sacral neuromodulation, most guidelines recommend urodynamics to confirm diagnosis of detrusor overactivity (DO). However, urodynamics may fail to show evidence of DO in up to 45% of cases, hence the need to evaluate its effectiveness and cost-effectiveness. FUTURE (Female Urgency, Trial of Urodynamics as Routine Evaluation) aims to test the hypothesis that, in women with refractory OAB, urodynamics and comprehensive clinical assessment is associated with superior patient-reported outcomes following treatment and is more cost-effective, compared to comprehensive clinical assessment only. Methods: FUTURE is a pragmatic, multi-centre, superiority randomised controlled trial. Women aged ≥ 18 years with refractory OAB or urgency predominant mixed urinary incontinence, and who have failed/not tolerated conservative and medical treatment, are considered for trial entry. We aim to recruit 1096 women from approximately 60 secondary/tertiary care hospitals across the UK. All consenting women will complete questionnaires at baseline, 3 months, 6 months and 15 months post-randomisation. The primary outcome is participant-reported success at 15 months post-randomisation measured using the Patient Global Impression of Improvement. The primary economic outcome is incremental cost per quality-adjusted life year gained at 15 months. The secondary outcomes include adverse events, impact on other urinary symptoms and health-related quality of life. Qualitative interviews with participants and clinicians and a health economic evaluation will also be conducted. The statistical analysis of the primary outcome will be by intention-to-treat. Results will be presented as estimates and 95% CIs. Discussion: The FUTURE study will inform patients, clinicians and policy makers whether routine urodynamics improves treatment outcomes in women with refractory OAB and whether it is cost-effective. Trial registration: ISRCTN63268739. Registered on 14 September 2017

    Quantifying the natural history of post-radical prostatectomy incontinence using objective pad test data

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    BACKGROUND: Urinary incontinence (UI) following radical prostatectomy is a well-recognized risk of the surgery. In most patients post-operative UI improves over time. To date, there is limited objective, quantitative data on the natural history of the resolution of post-prostatectomy UI. The purpose of this study was to define the natural history of post radical prostatectomy incontinence using an objective quantitative tool, the 1-hour standard pad test. METHODS: 203 consecutive patients underwent radical prostatectomy by a single surgeon between 03/98 & 08/03. A standardized 1-hour pad test was administered at subsequent postoperative clinic visits. The gram weight of urine loss was recorded and subdivided into four groups defined according to the grams of urine loss: minimal (<1 g), mild (>1, <10 g), moderate (10–50 g) and severe (>50 g). Patients were evaluated: at 2 weeks (catheter removal), 6 weeks, 18 weeks, 30 weeks, 42 weeks and 54 weeks. The data set was analyzed for average urine loss as well as grams of urine loss at each time point, the percentage of patients and the distribution of patients in each category. RESULTS: Mean follow up was 118 weeks. The majority of patients experienced incontinence immediately after catheter removal at 2 weeks that gradually improved with time. While continued improvement was noted to 1 year, most patients who achieved continence did so by 18 weeks post-op. CONCLUSION: While the majority of patients experience mild to severe UI immediately following catheter removal, there is a rapid decrease in leaked weight during the first 18 weeks following RRP. Patients continue to improve out to 1 year with greater than 90% having minimal leakage by International Continence Society criteria
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