3,076 research outputs found
Staged and non-staged anaerobic filters : microbial activity segregation, hydrodynamic behaviour and performance
This work describes a comparative study of staged and non-staged anaerobic flters for treating a synthetic dairy waste under similar operating conditions.
The effect of increasing the substrate concentration from 3 to 12 g COD dmˉ³ at a constant hydraulic residence time (HRT) of 2 days was evaluated with
respect to overall reactor performance, biogas production, volatile fatty acids
profiles along the height, methanogenic and acidogenic activity distribution, and
hydrodynamic behaviour. The potential maximum specific methanogenic activity
against acetate, hydrogen, propionate and butyrate and the lactose specific activity
were determined for sludge sampled from three different points in each
reactor, under two operating conditions (influent COD of 3 and 9 g COD
dmˉ³). Although all trophic groups involved in the anaerobic process were
found throughout the reactors, it was possible to identify different specific
sludges at different heights in both reactors. Performances of the two configurations
were very similar under the operating conditions tested and the plug flow
behaviour of the staged reactor was clearly reduced when the influent concentration
increased from 3 to 9 g COD dmˉ³.EU Human Capital and Mobility network Improved Application of Anaerobic
Digestion Technology - EXBCHRXCT 930262.Fundação para a Ciência e a Tecnologia – PEAM/SEL/517/95
A laser-induced mouse model with long-term intraocular pressure elevation
Purpose: To develop and characterize a mouse model with intraocular pressure (IOP) elevation after laser photocoagulation on the trabecular meshwork (TM), which may serve as a model to investigate the potential of stem cell-based therapies for glaucoma. Methods: IOP was measured in 281 adult C57BL/6 mice to determine normal IOP range. IOP elevation was induced unilaterally in 50 adult mice, by targeting the TM through the limbus with a 532-nm diode laser. IOP was measured up to 24 weeks post-treatment. The optic nerve damage was detected by electroretinography and assessed by semiautomatic counting of optic nerve axons. Effects of laser treatment on the TM were evaluated by histology, immunofluorescence staining, optical coherence tomography (OCT) and transmission electron microscopy (TEM). Results: The average IOP of C57BL/6 mice was 14.5±2.6 mmHg (Mean ±SD). After laser treatment, IOP averaged above 20 mmHg throughout the follow-up period of 24 weeks. At 24 weeks, 57% of treated eyes had elevated IOP with the mean IOP of 22.5±2.5 mmHg (Mean ±SED). The difference of average axon count (59.0%) between laser treated and untreated eyes was statistically significant. Photopic negative response (PhNR) by electroretinography was significantly decreased. CD45+ inflammatory cells invaded the TM within 1 week. The expression of SPARC was increased in the TM from 1 to 12 weeks. Histology showed the anterior chamber angle open after laser treatment. OCT indicated that most of the eyes with laser treatment had no synechia in the anterior chamber angles. TEM demonstrated disorganized and compacted extracellular matrix in the TM. Conclusions: An experimental murine ocular hypertension model with an open angle and optic nerve axon loss was produced with laser photocoagulation, which could be used to investigate stem cell-based therapies for restoration of the outflow pathway integrity for ocular hypertension or glaucoma. Copyright
Band-gap expansion in the surface-localized electronic structure of MoS2(0002)
The electronic band structure of MoS2 single crystals has been investigated using angle-resolved photoelectron spectroscopy and first-principles calculations. The orbital symmetry and k dispersion of these electronic states responsible for the direct and the indirect electronic band gaps have been unambiguously determined. By experimentally probing an increase of the electronic band gap, we conclude that a MoS2 (0002) surface localized state exists just below the valence band maximum at the Gamma point. This electronic state originates from the sulfur planes within the topmost layer. Our comprehensive study addresses the surface electronic structure of MoS2 and the role of van der Waals interlayer interactions.open112625Nsciescopu
Comparison of intravascular ultrasound guided versus angiography guided drug eluting stent implantation: a systematic review and meta-analysis
BACKGROUND: Intravascular ultrasound (IVUS) can be a useful tool during drug-eluting stents (DES) implantation as it allows accurate assessment of lesion severity and optimal treatment planning. However, numerous reports have shown that IVUS guided percutaneous coronary intervention is not associated with improved clinical outcomes, especially in non-complex patients and lesions. METHODS: We searched the literature in Medline, the Cochrane Library, and other internet sources to identify studies that compare clinical outcomes between IVUS-guided and angiography-guided DES implantation. Random-effects model was used to assess treatment effect. RESULTS: Twenty eligible studies with a total of 29,068 patients were included in this meta-analysis. The use of IVUS was associated with significant reductions in major adverse cardiovascular events (MACE, odds ratios [OR] 0.77, 95 % confidence intervals [CI] 0.71-0.83, P < 0.001), death (OR 0.62, 95 % CI 0.54-0.71, p < 0.001), and stent thrombosis (OR 0.59, 95 % CI: 0.47-0.73, P < 0.001). The benefit was also seen in the repeated analysis of matched and randomized studies. In stratified analysis, IVUS guidance appeared to be beneficial not only in patients with complex lesions or acute coronary syndromes (ACS) but also patients with mixed lesions or presentations (MACE: OR 0.69, 95 % CI: 0.60-0.79, p < 0.001, OR 0.81, 95 % CI 0.74-0.90, p < 0.001, respectively). By employing meta-regression analysis, the benefit of IVUS is significantly pronounced in patients with complex lesions or ACS with respect to death (p = 0.048). CONCLUSIONS: IVUS guidance was associated with improved clinical outcomes, especially in patients with complex lesions admitted with ACS. Large, randomized clinical trials are warranted to identify populations and lesion characteristics where IVUS guidance would be associated with better outcomes
Search for Second-Generation Scalar Leptoquarks in Collisions at =1.96 TeV
Results on a search for pair production of second generation scalar
leptoquark in collisions at =1.96 TeV are reported. The
data analyzed were collected by the CDF detector during the 2002-2003 Tevatron
Run II and correspond to an integrated luminosity of 198 pb. Leptoquarks
(LQ) are sought through their decay into (charged) leptons and quarks, with
final state signatures represented by two muons and jets and one muon, large
transverse missing energy and jets. We observe no evidence for production
and derive 95% C.L. upper limits on the production cross sections as well
as lower limits on their mass as a function of , where is the
branching fraction for .Comment: 9 pages (3 author list) 5 figure
Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-
We report a measurement of time-integrated CP-violation asymmetries in the
resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II
data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar
collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come
from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production
flavor of the charm meson is determined by the charge of the accompanying pion.
We apply a Dalitz-amplitude analysis for the description of the dynamic decay
structure and use two complementary approaches, namely a full Dalitz-plot fit
employing the isobar model for the contributing resonances and a
model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We
find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57
(stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry,
consistent with the standard model prediction.Comment: 15 page
Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+
We perform amplitude analyses of the decays , , and , and measure CP-violating
parameters and partial branching fractions. The results are based on a data
sample of approximately decays, collected with the
BABAR detector at the PEP-II asymmetric-energy factory at the SLAC National
Accelerator Laboratory. For , we find a direct CP asymmetry
in of , which differs
from zero by . For , we measure the
CP-violating phase .
For , we measure an overall direct CP asymmetry of
. We also perform an angular-moment analysis of
the three channels, and determine that the state can be described
well by the sum of the resonances , , and
.Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree
with published versio
Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters
This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio
Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-
We report the first observation of the baryonic flavor-changing neutral
current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a
statistical significance of 5.8 Gaussian standard deviations. This measurement
uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV
collected by the CDF II detector at the Tevatron collider. The total and
differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We
find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}.
We also report the first measurement of the differential branching ratio of B_s
-> phi mu+ mu- using 49 signal events. In addition, we report branching ratios
for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let
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