451 research outputs found
Cell cycle controls: potential targets for chemical carcinogens?
The progression of the cell cycle is controlled by the action of both positive and negative growth regulators. The key players in this activity include a family of cyclins and cyclin-dependent kinases, which are themselves regulated by other kinases and phosphatases. Maintenance of balanced cell cycle controls may be directly linked to genomic stability. Loss of the check-points involved in cell cycle control may result in unrepaired DNA damage during DNA synthesis or mitosis leading to genetic mutations and contributing to carcinogenesis
Addressing resistance to antibiotics in systematic reviews of antibiotic interventions
Antibiotics are among the most important interventions in healthcare. Resistance of bacteria to antibiotics threatens the effectiveness of treatment. Systematic reviews of antibiotic treatments often do not address resistance to antibiotics even when data are available in the original studies. This omission creates a skewed view, which emphasizes short-term efficacy and ignores the long-term consequences to the patient and other people. We offer a framework for addressing antibiotic resistance in systematic reviews. We suggest that the data on background resistance in the original trials should be reported and taken into account when interpreting results. Data on emergence of resistance (whether in the body reservoirs or in the bacteria causing infection) are important outcomes. Emergence of resistance should be taken into account when interpreting the evidence on antibiotic treatment in randomized controlled trials or systematic reviews
Intermittency analysis of high-lift airfoil with slat cove fillers
Experimental measurements were carried out to assess the aeroacoustic characteristics of 30P30N airfoil fitted with two different types of slat cove fillers at the aeroacoustic facility at the University of Bristol. The results are presented for the angle of attack α = 18◦ at a free-stream velocity of U∞ = 30 m/s which corresponds to a chord-based Reynolds number of Rec = 7 × 10◦ . Simultaneous measurements of the unsteady surface pressure were made at several locations in the vicinity of slat cove and at the far-field location to gain a deeper understanding of the slat noise generation mechanism. The results are analyzed using a higher-order statistical approach to determine the nature of the broadband hump seen at low-frequency for the 30P30N high-lift airfoil observed in recent studies and also to further understand the tone generation mechanism within the slat cavity. A series of cross-correlation and coherence of the unsteady pressure measurements are carried out to identify and isolate the low-frequency hump. Wavelet analysis is performed to investigate the nature of the slat-wing resonant intermittent events in both time and frequency domains. The far-field noise measurement results showed that significant noise reduction can be achieved by the use of slat cove fillers. A series of far-field and near-field correlation are also presented to show the propagated noise from the slat.5s
Evidence of Hot Carrier Extraction in Metal Halide Perovskite Solar Cells
The presence of hot carriers is presented in the operational properties of an
(FA,Cs)Pb(I, Br, Cl)3 solar cell at ambient temperatures and under practical
solar concentration. At 100 K, clear evidence of hot carriers is observed in
both the high energy tail of the photoluminescence spectra and from the
appearance of a non-equilibrium photocurrent at higher fluence in light J-V
measurements. At room temperature, however, the presence of hot carriers in the
emission at elevated laser fluence are shown to compete with a gradual red
shift in the PL peak energy as photo induced halide segregation begins to occur
at higher lattice temperature. The effects of thermionic emission of hot
carriers and the presence of a non-equilibrium carrier distribution are also
shown to be distinct from simple lattice heating. This results in large
unsaturated photocurrents at high powers as the Fermi distribution exceeds that
of the heterointerface controlling carrier transport and rectification
The SXS Collaboration catalog of binary black hole simulations
Accurate models of gravitational waves from merging black holes are necessary
for detectors to observe as many events as possible while extracting the
maximum science. Near the time of merger, the gravitational waves from merging
black holes can be computed only using numerical relativity. In this paper, we
present a major update of the Simulating eXtreme Spacetimes (SXS) Collaboration
catalog of numerical simulations for merging black holes. The catalog contains
2018 distinct configurations (a factor of 11 increase compared to the 2013 SXS
catalog), including 1426 spin-precessing configurations, with mass ratios
between 1 and 10, and spin magnitudes up to 0.998. The median length of a
waveform in the catalog is 39 cycles of the dominant
gravitational-wave mode, with the shortest waveform containing 7.0 cycles and
the longest 351.3 cycles. We discuss improvements such as correcting for moving
centers of mass and extended coverage of the parameter space. We also present a
thorough analysis of numerical errors, finding typical truncation errors
corresponding to a waveform mismatch of . The simulations provide
remnant masses and spins with uncertainties of 0.03% and 0.1% (
percentile), about an order of magnitude better than analytical models for
remnant properties. The full catalog is publicly available at
https://www.black-holes.org/waveforms .Comment: 33+18 pages, 13 figures, 4 tables, 2,018 binaries. Catalog metadata
in ancillary JSON file. v2: Matches version accepted by CQG. Catalog
available at https://www.black-holes.org/waveform
Experimental Investigation of Flow Around Three-Element High-Lift Airfoil with Morphing Fillers
Replication of TCF4 through Association and Linkage Studies in Late-Onset Fuchs Endothelial Corneal Dystrophy
Fuchs endothelial corneal dystrophy (FECD) is a common, late-onset disorder of
the corneal endothelium. Although progress has been made in understanding the
genetic basis of FECD by studying large families in which the phenotype is
transmitted in an autosomal dominant fashion, a recently reported genome-wide
association study identified common alleles at a locus on chromosome 18 near
TCF4 which confer susceptibility to FECD. Here, we report
the findings of our independent validation study for TCF4 using
the largest FECD dataset to date (450 FECD cases and 340 normal controls).
Logistic regression with sex as a covariate was performed for three genetic
models: dominant (DOM), additive (ADD), and recessive (REC). We found
significant association with rs613872, the target marker reported by Baratz
et al.(2010), for all three genetic models (DOM:
P = 9.33×10−35;
ADD:
P = 7.48×10−30;
REC:
P = 5.27×10−6).
To strengthen the association study, we also conducted a genome-wide linkage
scan on 64 multiplex families, composed primarily of affected sibling pairs
(ASPs), using both parametric and non-parametric two-point and multipoint
analyses. The most significant linkage region localizes to chromosome 18 from
69.94cM to 85.29cM, with a peak multipoint
HLOD = 2.5 at rs1145315 (75.58cM) under the DOM
model, mapping 1.5 Mb proximal to rs613872. In summary, our study presents
evidence to support the role of the intronic TCF4 single
nucleotide polymorphism rs613872 in late-onset FECD through both association and
linkage studies
A systematic review of operating room ventilation
Ventilation systems are the primary way of eliminating airborne pathogenic particles in an operating room (OR). However, such systems can be complex due to factors such as different surgical instruments, diverse room sizes, various staff counts, types of clothing used, different surgical types and duration, medications, and patient conditions. OR ventilation should provide a thermally comfortable environment for the surgical staff team members while preventing the patient from suffering from any extreme hypothermia. Many technical, logistical, and ethical implications need to be considered in the early stage of designing a ventilation system for an OR. Years of research and a significant number of publications have highlighted the controversy and disagreement among infection specialists, design engineers, and ventilation experts in this context. This review article aims to provide a good understanding of OR ventilation systems in the context of air quality and infection control from existing research and provide multidimensional insights for appropriate design and operation of the OR. To this end, we have conducted a systematic review of the literature, covering 253 articles in this context. Systematic review and meta-analyses were used to map the evidence and identify research gaps in the existing clinical, practical, and engineering knowledge. The present study is categorized into six research focuses: ventilation system, thermal comfort, staff work practice and obstacles, door operation and passage, air cleaning technology, emission rate, and clothing systems. In the conclusion, we summarize the key limitations of the existing studies and insights for future research direction
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