6,638 research outputs found
Sternal non-union in a professional hockey player: considerations for return to play
We describe a healthy 40-year old professional hockey player with an asymptomatic sternal non-union following aortic root surgery. The purpose of this case report is to make orthopedic surgeons aware of the possibility of this complication following sternotomy, and to discuss the considerations involved in return to play in contact sports. We will discuss our work-up, evaluation, and management of a sternal non-union in a professional athlete. Patient's consent has been obtained
Predictive coupled-cluster isomer orderings for some SiC () clusters; A pragmatic comparison between DFT and complete basis limit coupled-cluster benchmarks
The accurate determination of the preferred
isomer is important to guide experimental efforts directed towards synthesizing
SiC nano-wires and related polymer structures which are anticipated to be
highly efficient exciton materials for opto-electronic devices. In order to
definitively identify preferred isomeric structures for silicon carbon
nano-clusters, highly accurate geometries, energies and harmonic zero point
energies have been computed using coupled-cluster theory with systematic
extrapolation to the complete basis limit for set of silicon carbon clusters
ranging in size from SiC to . It is found that
post-MBPT(2) correlation energy plays a significant role in obtaining converged
relative isomer energies, suggesting that predictions using low rung density
functional methods will not have adequate accuracy. Utilizing the best
composite coupled-cluster energy that is still computationally feasible,
entailing a 3-4 SCF and CCSD extrapolation with triple- (T) correlation,
the {\it closo} isomer is identified to be the
preferred isomer in support of previous calculations [J. Chem. Phys. 2015, 142,
034303]. Additionally we have investigated more pragmatic approaches to
obtaining accurate silicon carbide isomer energies, including the use of frozen
natural orbital coupled-cluster theory and several rungs of standard and
double-hybrid density functional theory. Frozen natural orbitals as a way to
compute post MBPT(2) correlation energy is found to be an excellent balance
between efficiency and accuracy
Radiofrequency catheter ablation of supraventricular tachycardia substrates after mustard and senning operations for d-transposition of the great arteries
OBJECTIVES The purpose of this study was to determine the efficacy and risks of radiofrequency ablation of various forms of supraventricular tachycardia after Mustard and Senning operations for d-transposition of the great arteries. BACKGROUND In this patient group, the reported success rate of catheter ablation of intraatrial reentry tachycardia is about 70% with a negligible complication rate. There are no reports of the use of radiofrequency ablation to treat other types of supraventricular tachycardia. METHODS Standard diagnostic criteria were used to determine supraventricular tachycardia type. Appropriate sites for attempted ablation included 1) intraatrial reentry tachycardia: presence of concealed entrainment with a postpacing interval similar to tachycardia cycle length; 2) focal atrial tachycardia: a P-A interval ≤-20 ms; and 3) typical variety of atrioventricular (AV) node reentry tachycardia: combined electrographic and radiographic features. RESULTS Nine Mustard and two Senning patients underwent 13 studies to successfully ablate all supraventricular tachycardia substrates in eight (73%) patients. Eight of eleven (73%) patients having intraatrial reentry tachycardia, 3/3 having typical AV node reentry tachycardia, and 2/2 having focal atrial reentry tachycardia were successfully ablated. Among five patients having intraatrial reentry tachycardia (IART) and not having ventriculoatrial (V-A) conduction, two suffered high-grade AV block when ablation of the systemic venous portion of the medial tricuspid valve/inferior vena cava isthmus was attempted. CONCLUSIONS Radiofrequency catheter ablation can be effectively and safely performed for certain supraventricular tachycardia types in addition to intraatrial reentry. A novel catheter course is required for slow pathway modification. High-grade AV block is a potential risk of lesions placed in the systemic venous medial isthmus
HST ultraviolet spectral energy distributions for three ultraluminous infrared galaxies
We present HST Faint Object Camera ultraviolet (230 nm and 140 nm) images of
three ultraluminous infrared galaxies (ULIG: L_ir > 10^12 L_sun) selected from
the IRAS Revised Bright Galaxy Sample. The purpose is to estimate spectral
energy distributions (SEDs) to facilitate the identification of similar objects
at high redshift in deep optical, infrared, and submm surveys.
All three galaxies (VII Zw031 = IRAS F12112+0305, and IRAS F22491-1808) were
well detected at 230 nm. Two of the three were marginally detected at 140 nm.
The fluxes, together with ground-based optical and infrared photometry, are
used to compute SEDs over a wide wavelength range. The measured SEDs drop from
the optical to the ultraviolet, but the magnitude of the drop ranges from a
factor of ~3 in IRAS F22491-1808 to a factor of ~100 in VIIZw031. This is most
likely due to different internal extinctions. Such an interpretation is also
suggested by extrapolating to ultraviolet wavelengths the optical internal
extinction measured in VIIZw031. K-corrections are calculated to determine the
colors of the sample galaxies as seen at high redshifts. Galaxies like VIIZw031
have very low observed rest-frame UV fluxes which means that such galaxies at
high redshift will be extremely red or even missing in optical surveys. On the
other hand, galaxies like IRAS F12112+0305 and IRAS F22491-1808, if seen at
high redshift, would be sufficiently blue that they would not easily be
distinguished from normal field galaxies, and therefore, identified as ULIGs.
The implication is then that submillimeter surveys may be the only means of
properly identifying the majority of ULIGs at high redshift.Comment: AJ in press, TeX, 23 pages, 7 tab, 17 figs available also (at higher
resolution) from http://www.ast.cam.ac.uk~trentham/ufigs.htm
The Effects of Cold and Lower Body Negative Pressure on Cardiovascular Effects
Purpose. The purpose of this study is to determine how cold exposure and lower body negative pressure effected cardiovascular variables. Methods. Eleven males (20.3 years ± 2.7) underwent two 20-minute exposures to LBNP. During the 2 trials, the subjects were exposed to cold air (10°C) (COLD) and to ambient temperature (23°C) (AMB). The trials consisted of a 100-minute pre-LBNP period followed by a 20-minute exposure to LBNP and then a 15-minute recovery period. Cardiovascular variables were recorded every 30 minutes using bioimpedance. Results. When LBNP was applied during the AMB trials, stroke volume immediately decreased. During the COLD trial, there was a five-minute delay before the decrease in stroke volume. Heart rate increased immediately after LBNP initiation during the AMB trials but there was a delay in the increase during the COLD trials. That same pattern was followed with mean arterial blood pressures. Cerebral oxygenation was significantly lower throughout the COLD trial as compared to the AMB trials. Six subjects reported symptoms of syncope or presyncope during the AMB trials but there were no reports of symptoms during the COLD trials. Conclusion. From analysis of this data, cold improved the subject’s tolerance to LBNP
A new way to estimate disease prevalence from random partial-mouth samples
Standard partial-mouth estimators of chronic periodontitis that define an individual’s disease status solely in terms of selected sites underestimate prevalence. This study proposes an improved prevalence estimator based on randomly sampled sites and evaluates its accuracy in a well characterized population cohort
The female protective effect in autism spectrum disorder is not mediated by a single genetic locus
Background: A 4:1 male to female sex bias has consistently been observed in autism spectrum disorder (ASD). Epidemiological and genetic studies suggest a female protective effect (FPE) may account for part of this bias; however, the mechanism of such protection is unknown. Quantitative assessment of ASD symptoms using the Social Responsiveness Scale (SRS) shows a bimodal distribution unique to females in multiplex families. This leads to the hypothesis that a single, common genetic locus on chromosome X might mediate the FPE and produce the ASD sex bias. Such a locus would represent a major therapeutic target and is likely to have been missed by conventional genome-wide association study (GWAS) analysis. Methods: To explore this possibility, we performed an association study in affected versus unaffected females, considering three tiers of single nucleotide polymorphisms (SNPs) as follows: 1) regions of chromosome X that escape X-inactivation, 2) all of chromosome X, and 3) genome-wide. Results: No evidence of a SNP meeting the criteria for a single FPE locus was observed, despite the analysis being well powered to detect this effect. Conclusions: The results do not support the hypothesis that the FPE is mediated by a single genetic locus; however, this does not exclude the possibility of multiple genetic loci playing a role in the FPE.Intellectual and Developmental Disabilities Research Center at Washington University (NIH/NICHD) [P30 HD062171]; Simons Foundation (SFARI) [307705]; Canadian Institutes of Health Research; [R01 HD042541]SCI(E)[email protected]; [email protected]
Search for a Solution of the Pioneer Anomaly
In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the
first to explore the outer solar system and achieved stunning breakthroughs in
deep-space exploration. But beginning in about 1980 an unmodeled force of \sim
8 \times 10^{-8} cm/s^2, directed approximately towards the Sun, appeared in
the tracking data. It later was unambiguously verified as being in the data and
not an artifact. The cause remains unknown (although radiant heat remains a
likely origin). With time more and more effort has gone into understanding this
anomaly (and also possibly related effects). We review the situation and
describe ongoing programs to resolve the issue.Comment: 24 pages 8 figure
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