Intuitive Understanding of sigma Delocalization in Loose and sigma Localization in Tight Helical Conformations of a Saturated Chain Oligosilanes

Conformational effects on the amp; 963; electron delocalization in oligosilanes are addressed by Hartree Fock and time dependent density functional theory calculations B3LYP, 6 311G at MP2 optimized geometries of permethylated uniformly helical linear oligosilanes all amp; 969; SinR2n 2 up to n 16 and for backbone dihedral angles amp; 969; 55 180 . The extent of amp; 963; delocalization is judged by the partition ratio of the highest occupied molecular orbital and is reflected in the dependence of its shape and energy and of UV absorption spectra on n. The results agree with known spectra of all transoid loose helix conformers all [ 165] SinMe2n 2 and reveal a transition at amp; 969; amp; 8776;90 from the amp; 963; delocalized limit at amp; 969; 180 toward and close to the physically non realizable amp; 963; localized tight helix limit amp; 969; 0 with entirely different properties. The distinction is also obtained in the Hückel Ladder H and C models of amp; 963; delocalization. An easy intuitive way to understand the origin of the two contrasting limits is to first view the linear chain as two subchains with alternating primary and vicinal interactions amp; 963; hyperconjugation , one consisting of the odd and the other of the even amp; 963; SiSi bonds, and then allow the two subchains to interact by geminal interactions amp; 963; conjugatio

Impact of renal impairment on atrial fibrillation: ESC-EHRA EORP-AF Long-Term General Registry

Background: Atrial fibrillation (AF) and renal impairment share a bidirectional relationship with important pathophysiological interactions. We evaluated the impact of renal impairment in a contemporary cohort of patients with AF. Methods: We utilised the ESC-EHRA EORP-AF Long-Term General Registry. Outcomes were analysed according to renal function by CKD-EPI equation. The primary endpoint was a composite of thromboembolism, major bleeding, acute coronary syndrome and all-cause death. Secondary endpoints were each of these separately including ischaemic stroke, haemorrhagic event, intracranial haemorrhage, cardiovascular death and hospital admission. Results: A total of 9306 patients were included. The distribution of patients with no, mild, moderate and severe renal impairment at baseline were 16.9%, 49.3%, 30% and 3.8%, respectively. AF patients with impaired renal function were older, more likely to be females, had worse cardiac imaging parameters and multiple comorbidities. Among patients with an indication for anticoagulation, prescription of these agents was reduced in those with severe renal impairment, p <.001. Over 24 months, impaired renal function was associated with significantly greater incidence of the primary composite outcome and all secondary outcomes. Multivariable Cox regression analysis demonstrated an inverse relationship between eGFR and the primary outcome (HR 1.07 [95% CI, 1.01–1.14] per 10 ml/min/1.73 m2 decrease), that was most notable in patients with eGFR <30 ml/min/1.73 m2 (HR 2.21 [95% CI, 1.23–3.99] compared to eGFR ≥90 ml/min/1.73 m2). Conclusion: A significant proportion of patients with AF suffer from concomitant renal impairment which impacts their overall management. Furthermore, renal impairment is an independent predictor of major adverse events including thromboembolism, major bleeding, acute coronary syndrome and all-cause death in patients with AF

Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV

We report on the first measurement of the triangular $v_3$, quadrangular $v_4$, and pentagonal $v_5$ charged particle flow in Pb-Pb collisions at 2.76 TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow $v_2$ and $v_3$ have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.Comment: 10 pages, 4 figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

RAMAN SPECTRAL INVESTIGATION OF THE Hg(II)-SCN-H2OH_{2}O SYSTEM

$^{1}$. A. Tramewr, J. Chim. Phys. {\bf 59} , 232 (1962). $^{2}$. K. A. Taylor, T. V. Long and R. A. Plane, J. Chem. Phys. {\bf 47} , 138 (1966).Author Institution: Department of Physical Chemistry, University of BelgradeIn the course of extensive investigations of thiocyanate complexes of different metals, the new Raman bands have been recorded for the Hg(II)-SCN-$H_{2}O$ system, in addition to those due to free SCN ion. The new bands, located at $\sim$$240 cm^{-1}$, $\sim$$717 cm^{-1}$ and $\sim 2120 cm^{-1}$, were assumed as a consequence of Hg(II)-SCN complex formation. To obtain more evidence about the nature of species formed, a quantitative Raman spectral study combined with the mole-ratio method have been undertaken. The results are consistent with the presence of the $Hg(SCN)^{2-}_{4}$ species in solution and $Hg(SCN)_{2}$ in solid. The results were discussed and compared with those obtained $previously^{1,2}$

THE B-X TRANSITION OF B18OB^{18}O

Author Institution: Steacie Institute for Molecular Sciences, University of Belgrade; Faculty of Physical Chemistry, University of BelgradeThe $B - X$ bands of two isotopic species $^{11}B^{18}O$ and $^{10}B^{18}O$ have been observed for the first time. The bands were developed in emission from a low-pressure arc running in an atmosphere of the mixture of argon and oxygen 18 enriched up to 90 atom %. Twelve bandheads between 220 and 300 nm have been measured and vibrationaly assigned. The bands 1-0, 0-0 and 0-1 have been recorded under high dispersion and rotationally analyzed. Using determined molecular constants, Franck-Condon factors have been calculated and compared with visually estimated intensities of the bands. Full analyses of the bands will be presented

ACE and AT1 receptor gene polymorphisms and renal scarring in urinary bladder dysfunction

The objective of this study was to investigate whether DNA polymorphisms of the renin-angiotensin system (RAS) genes were associated with renal scar formation in pediatric patients with bladder dysfunction (BD). Although these children are born healthy, due to persistence of immature voiding habits and evolution of BD, some develop progressive renal damage. It has been suggested that the DD genotype of the angiotensin I-converting enzyme (ACE) gene might be an adverse renal prognostic factor. The insertion/deletion (I/D) polymorphism of the ACE gene and the A1166C polymorphism of the angiotensin II type 1 receptor (ATR1) gene were identified by polymerase chain reaction amplification in 42 children with BD (aged 5-14 years) and 198 healthy adult controls. Twelve children had urgency syndrome and 30 had dysfunctional voiding. Renal scarring was found in 16 patients, while 26 patients had normal kidneys on dimercaptosuccinic acid scan. In children with renal lesions there was significant over-representation of the DD genotype compared with either controls or patients without renal damage (P LT 0.05). On multivariate analysis, the DD genotype was the only factor that had a significant impact on renal scar formation, introducing a 2.51-fold risk (odds ratio 2.51, 95% confidence interval 1.04-6.04, P=0.04). The A1166C gene polymorphism was not significantly associated with the development of parenchymal damage in children with BD. Our findings introduce ACE I/D gene polymorphism as an independent risk factor for parenchymal destruction in pediatric patients with BD