4,065 research outputs found
Cardiovascular magnetic resonance reference ranges for the heart and aorta in Chinese at 3T.
Cardiovascular magnetic resonance (CMR) reference ranges have not been well established in Chinese. Here we determined normal cardiac and aortic reference ranges in healthy Singaporean Chinese and investigated how these data might affect clinical interpretation of CMR scans.In 180 healthy Singaporean Chinese (20 to 69 years old; males, n = 91), comprehensive cardiac assessment was performed using the steady state free precision technique (3T Ingenia, Philips) and images were analysed by two independent observers (CMR42, Circle Cardiovascular Imaging). Measurements were internally validated using standardized approaches: left ventricular mass (LVM) was measured in diastole and systole (with and without papillary muscles) and stroke volumes were compared in both ventricles. All reference ranges were stratified by sex and age; and indeterminate/borderline regions were defined statistically at the limits of the normal reference ranges. Results were compared with clinical measurements reported in the same individuals.LVM was equivalent in both phases (mean difference 3.0 ± 2.5 g; P = 0.22) and stroke volumes were not significantly different in the left and right ventricles (P = 0.91). Compared to females, males had larger left and right ventricular volumes (P 0.05 for all measures). In both sexes, age correlated negatively with left and right ventricular volumes; and positively with aortic sinus and sinotubular junction diameters (P < 0.0001 for all). There was excellent agreement in indexed stroke volumes in the left and right ventricles (0.1±5.7 mL/m2, 0.7±6.2 mL/m2, respectively), LVM (0.6±6.4 g/m2), atrial sizes and aortic root dimensions between values reported in clinical reports and our measured reference ranges.Comprehensive sex and age-corrected CMR reference ranges at 3T have been established in Singaporean Chinese. This is an important step for clinical practice and research studies of the heart and aorta in Asia
Pure Samples of Quark and Gluon Jets at the LHC
Having pure samples of quark and gluon jets would greatly facilitate the
study of jet properties and substructure, with many potential standard model
and new physics applications. To this end, we consider multijet and jets+X
samples, to determine the purity that can be achieved by simple kinematic cuts
leaving reasonable production cross sections. We find, for example, that at the
7 TeV LHC, the pp {\to} {\gamma}+2jets sample can provide 98% pure quark jets
with 200 GeV of transverse momentum and a cross section of 5 pb. To get 10 pb
of 200 GeV jets with 90% gluon purity, the pp {\to} 3jets sample can be used.
b+2jets is also useful for gluons, but only if the b-tagging is very efficient.Comment: 19 pages, 16 figures; v2 section on formally defining quark and gluon
jets has been adde
Hexagonal Boron Nitride Nanosheets Grown via Chemical Vapor Deposition for Silver Protection
© 2019 American Chemical Society. In this study, hexagonal boron nitride nanosheets (h-BNNS) have been grown on polycrystalline silver substrates via chemical vapor deposition (CVD) using ammonia borane as a precursor. The h-BNNS are of few-atomic-layer thickness and form continuous coverage over the whole Ag substrate. The atomically thin coating poses negligible interference to the reflectivity in the UV-visible range. The nanosheet coating also proves very effective in protecting Ag foil chemically. In contrast to bare Ag foil, the coated foil displayed only minor decolorization under high concentration of H2S. The study indicates that h-BNNS can be a promising protective coating for Ag based items such as jewelry or mirrors used in astronomical telescopes
HI-Tree: Mining High Influence Patterns Using External and Internal Utility Values
We propose an efficient algorithm, called HI-Tree, for mining high influence patterns for an incremental dataset. In traditional pattern mining, one would find the complete set of patterns and then apply a post-pruning step to it. The size of the complete mining results is typically prohibitively large, despite the fact that only a small percentage of high utility patterns are interesting. Thus it is inefficient to wait for the mining algorithm to complete and then apply feature selection to post-process the large number of resulting patterns. Instead of generating the complete set of frequent patterns we are able to directly mine patterns with high utility values in an incremental manner. In this paper we propose a novel utility measure called an influence factor using the concepts of external utility and internal utility of an item. The influence factor for an item takes into consideration its connectivity with its neighborhood as well as its importance within a transaction. The measure is especially useful in problem domains utilizing network or interaction characteristics amongst items such as in a social network or web click-stream data. We compared our technique against state of the art incremental mining techniques and show that our technique has better rule generation and runtime performance
Large enhancement of the photovoltaic effect in ferroelectric complex oxides through bandgap reduction
Tuning the bandgap in ferroelectric complex oxides is a possible route for improving the photovoltaic activity of materials. Here, we report the realization of this effect in epitaxial thin films of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 (BLT) suitably doped by Fe and Co. Our study shows that Co (BLCT) doping and combined Fe, Co (BLFCT) doping lead to a reduction of the bandgap by more than 1 eV compared to undoped BLT, accompanied by a surprisingly more efficient visible light absorption. Both BLCT and BLFCT films can absorb visible light with a wavelength of up to 500 nm while still exhibiting ferroelectricity, whereas undoped BLT only absorbs UV light with a wavelength of less than 350 nm. Correlated with its bandgap reduction, the BLFCT film shows a photocurrent density enhanced by 25 times compared to that of BLT films. Density functional theory calculations indicate that the bandgap contraction is caused by the formation of new energy states below the conduction bands due to intermixed transition metal dopants (Fe, Co) in BLT. This mechanism of tuning the bandgap by simple doping can be applied to other wide-bandgap complex oxides, thereby enabling their use in solar energy conversion or optoelectronic applications
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Rapid detection of BRCA1/2 recurrent mutations in Chinese breast and ovarian cancer patients with multiplex SNaPshot genotyping panels.
BRCA1/2 mutations are significant risk factors for hereditary breast and ovarian cancer (HBOC), its mutation frequency in HBOC of Chinese ethnicity is around 9%, in which nearly half are recurrent mutations. In Hong Kong and China, genetic testing and counseling are not as common as in the West. To reduce the barrier of testing, a multiplex SNaPshot genotyping panel that targeted 25 Chinese BRCA1/2 mutation hotspots was developed, and its feasibility was evaluated in a local cohort of 441 breast and 155 ovarian cancer patients. For those who tested negative, they were then subjected to full-gene testing with next-generation sequencing (NGS). BRCA mutation prevalence in this cohort was 8.05% and the yield of the recurrent panel was 3.52%, identifying over 40% of the mutation carriers. Moreover, from 79 Chinese breast cancer cases recruited overseas, 2 recurrent mutations and one novel BRCA2 mutation were detected by the panel and NGS respectively. The developed genotyping panel showed to be an easy-to-perform and more affordable testing tool that can provide important contributions to improve the healthcare of Chinese women with cancer as well as family members that harbor high risk mutations for HBOC
Study of optical Tamm states based on the phase properties of one-dimensional photonic crystals
Author name used in this publication: Chi Wah LeungVersion of RecordPublishe
Colored Resonant Signals at the LHC: Largest Rate and Simplest Topology
We study the colored resonance production at the LHC in a most general
approach. We classify the possible colored resonances based on group theory
decomposition, and construct their effective interactions with light partons.
The production cross section from annihilation of valence quarks or gluons may
be on the order of 400 - 1000 pb at LHC energies for a mass of 1 TeV with
nominal couplings, leading to the largest production rates for new physics at
the TeV scale, and simplest event topology with dijet final states. We apply
the new dijet data from the LHC experiments to put bounds on various possible
colored resonant states. The current bounds range from 0.9 to 2.7 TeV. The
formulation is readily applicable for future searches including other decay
modes.Comment: 29 pages, 9 figures. References updated and additional K-factors
include
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