1,448 research outputs found
1-CycloÂpropyl-6-fluoro-7-(4-nitroÂsoÂpiperazin-1-yl)-4-oxo-1,4-dihydroÂquinoline-3-carboxylic acid
The title compound, C17H17FN4O4, is a derivative of ciprofloxacin [1-cycloÂpropyl-6-fluoro-4-oxo-7-(1-piperazinÂyl)-1,4-dihydroÂquinoline-3-carboxylic acid]. The crystal packing is stabilized by interÂmolecular CâHâŻO hydrogen bonds together with ÏâÏ electron ring interÂactions [centroidâcentroid separations between quinoline rings of 3.5864â
(11) and 3.9339â
(13)â
Ă
]. A strong intraÂmolecular OâHâŻO hydrogen bonds is present as well as an intraÂmolecular CâHâŻF interÂaction
Quality of reporting of systematic reviews published in âevidence-basedâ Chinese journals
BACKGROUND: The number of systematic reviews (SRs)/meta-analyses (MAs) has increased dramatically in China over the past decades. However, evaluation of quality of reporting of systematic reviews published has not been undertaken. The objective of this study is to evaluate the quality of reporting of SRs/MAs assessing efficacy and/or harms of clinical interventions published in âevidence-basedâ Chinese journals. METHODS: Web-based database searches were conducted for the Chinese Journal of Evidence-based Medicine, the Journal of Evidence-Based Medicine, the Chinese Journal of Evidence Based Pediatrics, and the Chinese Journal of Evidence-Based Cardiovascular Medicine. SRs/MAs assessing efficacy and/or harms of clinical interventions were included. The cut-off was December 31st 2011. The PRISMA statement was applied to assess the quality of reporting. Each item was assessed as follows: âYesâ for total compliance, scored â1â; âpartialâ for partial compliance, scored â0.5â; and âNoâ for non-compliance, scored â0â. The review was considered to have major flaws if it received a total score of â€15.0, minor flaws if it received a total score of 15.5 to 21.0, and minimal flaws if it received a total score 21.5 to 27.0. Odds ratios were used for binary variables, and the mean difference was used for continuous variables. Analyses were performed using RevMan 5.0 software. RESULTS: Overall, 487 SRs/MAs were identified and assessed. The included reviews had medium quality with minor flaws based on PRISMA total scores (range: 8.5â26.0; mean: 19.6â±â3.3). The stratified analysis showed that SRs/MAs with more than 3 authors, from a university, hospitalâ+âuniversity cooperation, multiple affiliations (â„2), and funding have significantly higher quality of reporting of SRs/MAs; 58% of the included reviews were considered to have minor flaws (total score of 15.6 to 21.0). Only 9.6% of reviews were considered to have major flaws. Specific areas needing improvement in reporting include the abstract, protocol and registration, and characteristics of the search. CONCLUSIONS: The reporting of SRs published in âevidence-basedâ Chinese journals is poor and needs to be improved in order for reviews to be useful. SR authors should use the PRISMA checklist to ensure complete and accurate accounts of their SRs
Preparation and Photoeletrochemical Performance of CdS Quantum Dot Sensitized ZnO Nanorod Array Electrodes
We sensitized CdS quantum dots on a ZnO nanorod array electrode by the successive ionic layer adsorption and reaction method. Scanning electron microscopy (SEM), X. ray diffraction (XRD), and transmission electron microscopy (TEM) experiments were performed to characterize the morphology, crystalline phase, and grain size of the CdS quantum dot sensitized ZnO nanorod array electrodes. The effect of CdS deposition cycle number and the precursor concentration were studied by photocurrent-potential characteristics and photocurrent spectra. The results showed that the best photoelectrochemical performance was obtained at 0.1 mol.L-1 for both Cd2+ and S2- after 15 cycles. Meanwhile, the composite films exhibited a remarkably enhanced photoelectric conversion efficiency compared with the ZnO nanorods array films and with CdS quantum dot electrodes. The monochromatic incident photon. to. electron conversion efficiency (IPCE) was as high as 76% at 380 nm. This may be attributed to the broad light harvesting capability of CdS and the efficient separation of photogenerated carriers on its interface. The reason for this enhancement was further confirmed by a photoluminescent experiment. The results showed that sensitization with CdS quantumdots reduced the recombination of electron and hole pairs resulting in an enhancement in the photocurrent.National Natural Science Foundation of China [20433040
The role of the microbiota-gut-brain axis and intestinal microbiome dysregulation in Parkinsonâs disease
Parkinsonâs disease (PD) is a complex progressive neurodegenerative disease associated with aging. Its main pathological feature is the degeneration and loss of dopaminergic neurons related to the misfolding and aggregation of α-synuclein. The pathogenesis of PD has not yet been fully elucidated, and its occurrence and development process are closely related to the microbiota-gut-brain axis. Dysregulation of intestinal microbiota may promote the damage of the intestinal epithelial barrier, intestinal inflammation, and the upward diffusion of phosphorylated α-synuclein from the enteric nervous system (ENS) to the brain in susceptible individuals and further lead to gastrointestinal dysfunction, neuroinflammation, and neurodegeneration of the central nervous system (CNS) through the disordered microbiota-gut-brain axis. The present review aimed to summarize recent advancements in studies focusing on the role of the microbiota-gut-brain axis in the pathogenesis of PD, especially the mechanism of intestinal microbiome dysregulation, intestinal inflammation, and gastrointestinal dysfunction in PD. Maintaining or restoring homeostasis in the gut microenvironment by targeting the gut microbiome may provide future direction for the development of new biomarkers for early diagnosis of PD and therapeutic strategies to slow disease progression
Diatom-based water-table reconstruction in Sphagnum peatlands of northeastern China
Peatlands are important ecosystems for biodiversity conservation, global carbon cycling and water storage. Hydrological changes due to climate variability have accelerated the degradation of global and regional ecosystem services of peatlands. Diatoms are important producers and bioindicators in wetlands, but comprehensive diatom-based inference models for palaeoenvironmental reconstruction in peatlands are scarce. To explore the use of diatoms for investigating peatland hydrological change, this study established a training set consisting of diatom composition and twelve environmental factors from 105 surface samples collected from five Sphagnum peatlands in northeastern China. Diatom communities were dominated by Eunotia species. Ordination analyses showed that depth to the water table (DWT) was the most important factor influencing diatom distribution, independently accounting for 4.99% of total variance in diatom data. Accordingly, a diatom-based DWT transfer function was developed and thoroughly tested. The results revealed that the best-performing model was based on weighted averaging with inverse deshrinking (R2 = 0.66, RMSEP = 8.8 cm with leave-one-out cross validation). Quantitative reconstruction of DWT on a short peat core collected from the Aershan Peatland (Inner Mongolia) recorded climate-mediated hydrological changes over the last two centuries. This study presents the first diatom-water table transfer function in Sphagnum peatlands, and highlights the potential of diatoms as a powerful tool to assess the magnitude of past hydrological changes in peatlands of northeastern China, as well as similar peaty environments worldwide
DHAV-1 2A1 Peptide â A Newly Discovered Co-expression Tool That Mediates the Ribosomal âSkippingâ Function
Duck hepatitis A virus 1 (DHAV-1) belongs to the genus Avihepatovirus in the family Picornaviridae. Little research has been carried out on the non-structural proteins of this virus. This study reports that 2A1 protein, the first non-structural protein on the DHAV-1 genome, has a ribosomal âskippingâ function mediated by a â-GxExNPGP-â motif. In addition, we prove that when the sequence is extended 10aa to VP1 from the N-terminal of 2A1, the ribosome âskipsâ completely. However, as the N-terminus of 2A is shortened, the efficiency of ribosomal âskippingâ reduces. When 2A1 is shortened to 10aa, it does not function. In addition, we demonstrate that N18, P19 G20, and P21 have vital roles in this function. We find that the expression of upstream and downstream proteins linked by 2A1 is different, and the expression of the upstream protein is much greater than that of the downstream protein. In addition, we demonstrate that it is the nature of 2A1 that is responsible for the expression imbalance. We also shows that the protein âcleavageâ is not due to RNA âcleavageâ or RNA transcription abnormalities, and the expressed protein level is independent of RNA transcriptional level. This study provides a systematic analysis of the activity of the DHAV-1 2A1 sequence and, therefore, adds to the âtool-boxâ that can be deployed for the co-expression applications. It provides a reference for how to apply 2A1 as a co-expression tool
Prospects for detection rate of very-high-energy {\gamma}-ray emissions from short {\gamma}-ray bursts with the HADAR experiment
The observation of short gamma ray bursts (SGRBs) in the TeV energy range
plays an important role in understanding the radiation mechanism and probing
new areas of physics such as Lorentz invariance violation. However, no SGRB has
been observed in this energy range due to the short duration of SGRBs and the
weakness of current experiments. New experiments with new technology are
required to detect sub-TeV SGRBs. In this work, we observe the very high energy
(VHE) -ray emissions from SGRBs and calculate the annual detection rate
with the High Altitude Detection of Astronomical Radiation HADAR (HADAR)
experiment. First, a set of pseudo-SGRB samples is generated and checked using
the observations of Fermi-GBM, Fermi-LAT, and SWIFT measurements. The annual
detection rate is calculated from these SGRB samples based on the performance
of the HADAR instrument. As a result, the HADAR experiment can detect 0.5 SGRB
per year if the spectral break-off of -rays caused by the internal
absorption is larger than 100 GeV. For a GRB09010-like GRB in HADAR's view, it
should be possible to detect approximately 2000 photons considering the
internal absorption. With a time delay assumption due to the Lorentz invariance
violation effects, a simulated light curve of GRB090510 has evident energy
dependence. We hope that the HADAR experiment can perform the SGRB observations
and test our calculations in the future
Household inhalants exposure and nasopharyngeal carcinoma risk: a large-scale case-control study in Guangdong, China
Study of
We present an analysis of the decay based
on data collected by the BESIII experiment at the resonance. Using
a nearly background-free sample of 18262 events, we measure the branching
fraction . For GeV/ the partial branching fraction is
. A partial wave analysis shows that the dominant
component is accompanied by an \emph{S}-wave contribution accounting for
of the total rate and that other components are
negligible. The parameters of the resonance and of the
form factors based on the spectroscopic pole dominance predictions are also
measured. We also present a measurement of the helicity
basis form factors in a model-independent way.Comment: 17 pages, 6 figure
Study of and and
We study the decays of and to the final states
and based on a single
baryon tag method using data samples of
and events collected with
the BESIII detector at the BEPCII collider. The decays to
are observed for the first time. The
measured branching fractions of and
are in good agreement with, and much
more precise, than the previously published results. The angular parameters for
these decays are also measured for the first time. The measured angular decay
parameter for , , is found to be negative, different to the other
decay processes in this measurement. In addition, the "12\% rule" and isospin
symmetry in the and and
systems are tested.Comment: 11 pages, 7 figures. This version is consistent with paper published
in Phys.Lett. B770 (2017) 217-22
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