3,836 research outputs found
The Interaction of HCl and Crystalline Ice Clusters at Cryogenic Temperatures: Evidence of the Molecular Complex
No full text1. Lance Delzeit, Brad Rowland, and J. Paul Devlin; J. Phys. Chem. 97 10312 (1993). 2. B. S. Ault and G. C. Pimentel; J. Phys. Chem. 77 57 (1973). 3. A. Schriver, et. al.; J. Phys. Chem. 87 2095 (1977). 4. G. Kroes and D. C. Clary; J. Phys. Chem. 96 7079 (1992). 5. Brad Rowland, Mark Fisher, and J. Paul Devlin; J. Chem. Phys. 95 1378 (1991).Author Institution: Oklahoma State University, Stillwater, OK 74078The addition of HCl to the surface of crystalline ice clusters at cryogenic temperatures produces spectroscopic changes which can be related to the formation of the hydronium ion and the HCl acting as a molecular adsorbate. The hydronium ion is identified from its IR active modes below . Evidence for the HCl acting as a molecular adsorbate is its effect on the dangling-hydrogen (d-H) mode and the appearance of a band. Analogous spectra for with the and the show two bands relative to the one band in the region due to the interaction. The single band in the HCl system is attributed to the near overlap of the bands due to the molecular and ionic interaction of the HCl and . Reference to matrix and computational will show the plausibility of the presence of the molecular complex. Shifting of the d-H band is a common effect for molecularly adsorbed species on the surface of The shifting of the d-H to a position yet unobserved for common adsorbates gives strong evidence of the HCl acting as a molecular adsorbate
T-L SPLITTINGS FROM POLARIZED ATR SPECTRA OF UNIAXIAL CRYSTALS
No full textR. P. J. Cooney, C. Thayer, P. C. Li, and J. P. Devlin, J. Chem. Phys. 51, 302 (1969).""Author Institution: Chemistry Department, Oklahoma State University; Department of Chemistry, Oregon State UniversityOriented films of the trigonal alkali metal nitrates, which behave effectively as single crystals, can be grown in optical contact with silicon and Irtran 6 atr elements from the corresponding pure melts. Contrary to earlier spectra from such crystals are not strongly influenced by crystal distortion at the interface. Rather the unusual experimental curves, typified by a nearly complete lack of TE and TM band overlap for the mode of (II), have been found to be predictable using optical parameters generated from a damped oscillator model. Substitution of the empirically calibrated optical constants into Fresnel’s equations for the case in point (unique crystal axis perpendicular to the sample-element interface) yields nearly quantitative agreement with the experimental curves
Hundreds of variants clustered in genomic loci and biological pathways affect human height
No full textMost common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits(1), but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait(2,3). The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways
Minimally invasive management of bile leaks after blunt liver trauma in children
No full textBackground: Management of bile leaks after blunt abdominal trauma remains controversial. Conventionally, open surgery has been considered necessary, but new modalities of treatment, including endoscopic biliary stenting and laparoscopy, offer a minimally invasive alternative. Materials and Methods: A retrospective review of all cases of blunt liver trauma in children treated at our institution between May 2002 and October 2004 was performed looking for possible biliary injury. Results: Five children (3 boys), median age 13 years (range, 10-15 years), were referred to our institution at a median time of 4 days (1-15 days) after the initial trauma. Mechanism of injury was motor vehicle accident (n = 3), fall from a motorbike/Quad bike (n = 2), and a scooter handlebar injury (n = 1). Two, who were hemodynamically unstable, required laparotomy within 24 hours, although their subsequent management was minimally invasive. Endoscopic retrograde cholangiopancreatography, performed at a median time of 15 days (2-28 days), demonstrated an intrahepatic biliary leak in all 5 patients. Biliary stenting was performed in each case, with 2 also having a sphincterotomy. One subsequently developed a bile duct stricture that was managed by endoscopic dilatation. Four required additional percutaneous external drainage of intraabdominal collections. Two underwent laparoscopy to facilitate peritoneal lavage and rule out bowel injuries. No child required open surgery to treat the bite leak. Median hospital stay was 43 days (range, 15-58 days). Conclusions: A minimally invasive, multidisciplinary approach to traumatic bile leaks, as an alternative to open surgery, is practical and safe. It requires flexibility, particularly if the diagnosis has been delayed, and may still involve a prolonged hospital stay. (c) 2006 Elsevier Inc. All rights reserve
Il contributo della stimolazione cerebrale ala comprensione dell’organizzazione del linguaggio
No full textVIBRATIONAL SPECTRA OF AND ISOLATED IN AND (S): PROTON TRANSFER RATES IN HYDROGEN BONDED SOLIDS
No full textG. Ritzhaupt and J. P. Devlin, J. Chem. Physics 67, 4779 (1977). G. Ritzhaupt, C. Thornton, and J. P. Devlin, Chem. Phys. Lett. 59, 420 (1978). M. G. Sceats. M. Stavola, and S. A. Rice, private communication.Author Institution:Recent studies have shown that proton transfer processes cease at low temperatures in and . Consequently, it is possible, via a matrix isolation approach to isolate molecules such as and , intact, in otherwise pure glassy or crystalline and . has been studied isolated in amorphous and crystalline where decoupling of the vibrational modes has permitted evaluation of the relative importance of correlation field effects, the coupling of intramolecular bond oscillators and Fermi resonance similar decoupling results are now available for in showing that the correlation field effects are small and nearly of magnitude less than for crystalline or amorphous . These results will be presented together with spectroscopically determined proton exchange rates and conclusions regarding energy barriers and mechanisms for proton exchange
Investigating sentence weighting components for automatic summarisation
No full textThe work described here initially formed part of a triangulation exercise to establish the effectiveness of the Query Term Order algorithm. The methodology produced subsequently proved to be a reliable indicator of quality for summarising English web documents. We utilised the human summaries from the Document Understanding Conference data, and generated queries automatically for testing the QTO algorithm. Six sentence weighting schemes that made use of Query Term Frequency and QTO were constructed to produce system summaries, and this paper explains the process of combining and balancing the weighting components. We also examined the five automatically generated query terms in their different permutations to check if the automatic generation of query terms resulting bias. The summaries produced were evaluated by the ROUGE-1 metric, and the results showed that using QTO in a weighting combination resulted in the best performance. We also found that using a combination of more weighting components always produced improved performance compared to any single weighting component
Prediction of optical rotation using density functional theory: 6,8-diabicyclo [3.2.1] octanes
No full textWe report calculations of the optical rotations of six 6,8-dioxabicyclo[3.2.1]octanes using ab initio density functional theory (DFT). GIAO basis sets are used to ensure origin independence of predicted rotations. Large basis sets including diuse functions are used to minimize basis set error. The signs of [a]D are correctly predicted. Magnitudes dier from experiment by 10±20 degrees [dm (g/cc)] 1 on average. Agree- ment with experiment is improved by inclusion of solvent eects via the Polarized Continuum Model (PCM). The results support the conclusion that DFT/GIAO/PCM calculations of speci®c rotations can be useful in elucidating the absolute con®gurations of chiral molecules
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