258 research outputs found
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In Vitro Antimicrobial Activities of Organic Acids and Their Derivatives on Several Species of Gram-Negative and Gram-Positive Bacteria.
The objective of this study was to determine the in vitro antimicrobial activity of several organic acids and their derivatives against Gram-positive (G+) and Gram-negative (G-) bacteria. Butyric acid, valeric acid, monopropionin, monobutyrin, monovalerin, monolaurin, sodium formate, and ProPhorce-a mixture of sodium formate and formic acid (40:60 w/v)-were tested at 8 to 16 concentrations from 10 to 50,000 mg/L. The tested bacteria included G- bacteria (Escherichia coli, Salmonella enterica Typhimurium, and Campylobacter jejuni) and G+ bacteria (Enterococcus faecalis, Clostridium perfringens, Streptococcus pneumoniae, and Streptococcus suis). Antimicrobial activity was expressed as minimum inhibitory concentration (MIC) of tested compounds that prevented growth of tested bacteria in treated culture broth. The MICs of butyric acid, valeric acid, and ProPhorce varied among bacterial strains with the lowest MIC of 500-1000 mg/L on two strains of Campylobacter. Sodium formate at highest tested concentrations (20,000 mg/L) did not inhibit the growth of Escherichia coli, Salmonella Typhimurium, and Enterococcus faecalis, but sodium formate inhibited the growth of other tested bacteria with MIC values from 2000 to 18,800 mg/L. The MIC values of monovalerin, monolaurin, and monobutyrin ranged from 2500 to 15,000 mg/L in the majority of bacterial strains. Monopropionin did not inhibit the growth of all tested bacteria, with the exception that the MIC of monopropionin was 11,300 mg/L on Clostridia perfringens. Monolaurin strongly inhibited G+ bacteria, with the MIC value of 10 mg/L against Streptococcus pneumoniae. The MIC tests indicated that organic acids and their derivatives exhibit promising antimicrobial effects in vitro against G- and G+ bacteria that are resistant to antimicrobial drugs. The acid forms had stronger in vitro antimicrobial activities than ester forms, except that the medium chain fatty acid ester monolaurin exhibited strong inhibitory effects on G+ bacteria
PlanimetrÃa de alta resolución del dolmen de Menga (Antequera, Málaga) mediante escaneado láser terrestre, levantamiento 3D y fotogrametrÃa
Dielectric metasurfaces can achieve flexible beam manipulations. Herein, we study dielectric metasurfaces with different refractive indices, periods, incident angles, and cross-sectional shapes to determine the metasurface working mechanisms. Perfect transmission mainly depends on multipolar interference that can be used to control the transmission modes through the hybrid periods, hybrid cross sections, and multilayers. Perfect reflection is strongly influenced by the period of the metasurface and occurs only when the period is shorter than incident wavelength, which can be attributed to the lattice coupling. Furthermore, lattice coupling can be classified into two types with distinct properties: vertical mode and horizontal mode coupling. The vertical mode appears when the effective wavelength matches the feature size, whereas the horizontal mode only appears when the incident wavelength is close to the period. The horizontal mode is sensitive to the incident angle. The revealed functioning mechanisms enable further practical applications of metasurfaces
Topological Atomic Spinwave Lattices by Dissipative Couplings
Recent experimental advance in creating dissipative couplings provides a new
route for engineering exotic lattice systems and exploring topological
dissipation. Using the spatial lattice of atomic spinwaves in a vacuum vapor
cell, where purely dissipative couplings arise from diffusion of atoms, we
experimentally realize a dissipative version of the Su-Schrieffer-Heeger (SSH)
model. We construct the dissipation spectra of the topological or trivial
lattices via electromagnetically-induced-transparency (EIT) spectroscopy. The
topological dissipation spectrum is found to exhibit edge modes at dissipation
rates within a dissipative gap, decoupled from the bulk. We also validate
chiral symmetry of the dissipative SSH couplings. This work paves the way for
realizing topology-enabled quantum correlations and non-Hermitian topological
quantum optics via dissipative couplings.Comment: 5 pages, 4 figure
Beam Manipulation Mechanisms of Dielectric Metasurfaces
Dielectric metasurfaces can achieve flexible beam manipulations. Herein, we study dielectric metasurfaces with different refractive indices, periods, incident angles, and cross-sectional shapes to determine the metasurface working mechanisms. Perfect transmission mainly depends on multipolar interference that can be used to control the transmission modes through the hybrid periods, hybrid cross sections, and multilayers. Perfect reflection is strongly influenced by the period of the metasurface and occurs only when the period is shorter than incident wavelength, which can be attributed to the lattice coupling. Furthermore, lattice coupling can be classified into two types with distinct properties: vertical mode and horizontal mode coupling. The vertical mode appears when the effective wavelength matches the feature size, whereas the horizontal mode only appears when the incident wavelength is close to the period. The horizontal mode is sensitive to the incident angle. The revealed functioning mechanisms enable further practical applications of metasurfaces
The efficacy of dapagliflozin for type 1 diabetes: a meta-analysis of randomized controlled studies
Introduction: The efficacy of dapagliflozin for type 1 diabetes remains
controversial. We conduct a systematic review and meta-analysis to
explore the treatment efficacy of dapagliflozin versus placebo in
patients with type 1 diabetes. Methods: We have searched PubMed,
EMbase, Web of science, EBSCO and Cochrane library databases through
May 2019 for randomized controlled trials (RCTs) assessing the effect
of dapagliflozin versus placebo for type 1 diabetes. This meta-analysis
is performed using the random-effect model. Results: Six RCTs are
included in the meta-analysis. Overall, compared with control group for
type 1 diabetes, dapagliflozin treatment shows favorable impact on
glycated hemoglobin HbA1c ( standard mean difference SMD=-3.93; 95%
confidence interval CI =-4.44 to -3.48; P<0.00001), HbA1c reduction
of 650.5% (risk ratio RR=1.98; 95% CI=1.65 to 2.39; P<0.00001),
and fasting plasma glucose FPG (SMD=-0.93; 95% CI=-1.77 to -0.10;
P=0.03). There is no statistical difference of hypoglycemia (RR=1.09;
95% CI=0.66 to 1.79; P=0.75) or adverse events (RR=1.07; 95% CI=0.96 to
1.20; P=0.20) between two groups, but the incidence of ketone-related
events is higher than those in control group (RR=0.28; 95% CI=3.96 to
11.52; P=0.01). Conclusions: Dapagliflozin treatment benefits to reduce
HbA1c and FPG for type 1 diabetes
Genetic Variants on Chromosome 8q24 and Colorectal Neoplasia Risk: A Case-Control Study in China and a Meta-Analysis of the Published Literature
Previous studies have found that common genetic variants on chromosome 8q24 are associated with the risk of developing colorectal neoplasia. We conducted a hospital-based case-control study, including 435 cases and 788 unrelated controls to investigate the associations between common variants on 8q24 and the risk of colorectal cancer in a Chinese population. We also evaluated the association of rs6983267 with colorectal neoplasia in the published literature via a meta-analysis study. We found that rs6983267 was significantly associated with the risk of colorectal cancer in the Chinese population, with an adjusted odds-ratio (OR) for the GT heterozygotes and GG homozygotes of 1.30 (95% CI  = 0.98–1.71, P = 0.069) and 1.66 (95% CI  = 1.18–2.34, P = 0.004), respectively, compared to the TT homozygotes, with a P-trend value of 0.003. No association was found for the other three loci (rs16901979, rs1447295 and rs7837688). In the meta-analysis of the published genetic association studies, the rs6983267 variant was found to be associated with an increased risk of colorectal neoplasia. The heterozygous GT carriers showed a 20% increased risk of colorectal neoplasia (OR  = 1.20, 95% CI  = 1.16–1.25; random effects model) with a summary OR for homozygous GG carriers of 1.39 (95% CI  = 1.32–1.48; random effects model) compared to the TT genotype carriers. We found no significant differences between the association of rs6983267 and colorectal cancer and colorectal adenomas. In summary, our study confirms that the variant rs6983267 is a risk factor for colorectal neoplasia in various populations, including the Chinese population
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