9 research outputs found

    Quantum Theory Of Atoms In Molecules/charge-charge Flux-dipole Flux Models For Fundamental Vibrational Intensity Changes On H-bond Formation Of Water And Hydrogen Fluoride.

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    The Quantum Theory of Atoms In Molecules/Charge-Charge Flux-Dipole Flux (QTAIM/CCFDF) model has been used to investigate the electronic structure variations associated with intensity changes on dimerization for the vibrations of the water and hydrogen fluoride dimers as well as in the water-hydrogen fluoride complex. QCISD/cc-pVTZ wave functions applied in the QTAIM/CCFDF model accurately provide the fundamental band intensities of water and its dimer predicting symmetric and antisymmetric stretching intensity increases for the donor unit of 159 and 47 km mol(-1) on H-bond formation compared with the experimental values of 141 and 53 km mol(-1). The symmetric stretching of the proton donor water in the dimer has intensity contributions parallel and perpendicular to its C2v axis. The largest calculated increase of 107 km mol(-1) is perpendicular to this axis and owes to equilibrium atomic charge displacements on vibration. Charge flux decreases occurring parallel and perpendicular to this axis result in 42 and 40 km mol(-1) total intensity increases for the symmetric and antisymmetric stretches, respectively. These decreases in charge flux result in intensity enhancements because of the interaction contributions to the intensities between charge flux and the other quantities. Even though dipole flux contributions are much smaller than the charge and charge flux ones in both monomer and dimer water they are important for calculating the total intensity values for their stretching vibrations since the charge-charge flux interaction term cancels the charge and charge flux contributions. The QTAIM/CCFDF hydrogen-bonded stretching intensity strengthening of 321 km mol(-1) on HF dimerization and 592 km mol(-1) on HF:H2O complexation can essentially be explained by charge, charge flux and their interaction cross term. Atomic contributions to the intensities are also calculated. The bridge hydrogen atomic contributions alone explain 145, 237, and 574 km mol(-1) of the H-bond stretching intensity enhancements for the water and HF dimers and their heterodimer compared with total increments of 149, 321, and 592 km mol(-1), respectively.14008430

    An atom in molecules study of infrared intensity enhancements in fundamental donor stretching bands in hydrogen bond formation

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    Vibrational modes ascribed to the stretching of X–H bonds from donor monomers (HXdonor) in complexes presenting hydrogen bonds (HF⋯HF, HCl⋯HCl, HCN⋯HCN, HNC⋯HNC, HCN⋯HF, HF⋯HCl and H2O⋯HF) exhibit large (4 to 7 times) infrared intensity increments during complexation according to CCSD/cc-pVQZ-mod calculations. These intensity increases are explained by the charge–charge flux–dipole flux (CCFDF) model based on multipoles from the Quantum Theory of Atoms in Molecules (QTAIM) as resulting from a reinforcing interaction between two contributions to the dipole moment derivatives with respect to the vibrational displacements: charge and charge flux. As such, variations that occur in their intensity cross terms in hydrogen bond formation correlate nicely with the intensity enhancements. These stretching modes of HXdonor bonds can be approximately modeled by sole displacement of the positively charged hydrogens towards the acceptor terminal atom with concomitant electronic charge transfers in the opposite direction that are larger than those occurring for the H atom displacements of their isolated donor molecules. This analysis indicates that the charge–charge flux interaction reinforcement on H-bond complexation is associated with variations of atomic charge fluxes in both parent molecules and small electronic charge transfers between them. The QTAIM/CCFDF model also indicates that atomic dipole flux contributions do not play a significant role in these intensity enhancements16452492024928CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP300544/2009-0; 140711/2013-9; 140916/ 2011-32010/18743-1; 2009/09678-1; 2011/02807-

    Systematic Theoretical Study of Non-nuclear Electron Density Maxima in Some Diatomic Molecules

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    First, exploratory calculations were performed to investigate the presence of non-nuclear maxima (NNMs) in ground-state electron densities of homonuclear diatomic molecules from hydrogen up to calcium at their equilibrium geometries. In a second stage, only for the cases in which these features were previously detected, a rigorous analysis was carried out by several combinations of theoretical methods and basis sets in order to ensure that they are not only calculation artifacts. Our best results support that Li<sub>2,</sub> B<sub>2</sub>, C<sub>2</sub>, and P<sub>2</sub> are molecules that possess true NNMs. A NNM was found in values obtained from the largest basis sets for Na<sub>2</sub>, but it disappeared at the experimental geometry because optimized bond lengths are significantly inaccurate for this case (deviations of 0.10 Å). Two of these maxima are also observed in Si<sub>2</sub> with CCSD and large basis sets, but they are no longer detected as core–valence correlation or multiconfigurational wave functions are taken into account. Therefore, the NNMs in Si<sub>2</sub> can be considered unphysical features due to an incomplete treatment of electron correlation. Finally, we show that a NNM is encountered in LiNa, representing the first discovery of such electron density maxima in a heteronuclear diatomic system at its equilibrium geometry, to our knowledge. Some results for LiNa, found in variations in internuclear distances, suggest that molecular electric moments, such as dipole and quadrupole, are sensitive to the presence of NNMs

    Prevalence of cervical intraepithelial neoplasia and invasive carcinoma based on cytological screening in the region of Campinas, São Paulo, Brazil Prevalência da neoplasia intra-epitelial cervical e do carcinoma invasivo com base no rastreamento citológico na região de Campinas, São Paulo, Brasil

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    This study aimed to estimate and analyze the prevalence of cervical intraepithelial neoplasia (CIN) and invasive cervical carcinoma based on cytological diagnosis. The study included 120,635 women undergoing cytological exams in public health services in the region of Campinas, São Paulo State, Brazil, between September 1998 and March 1999. Prevalence rates per 100,000 women were: 354 for CIN I; 255 for CIN II; 141 for CIN III; and 24 for invasive carcinoma. As age increased, prevalence rates and prevalence ratios decreased for CIN grades I and II and increased for CIN III until the 50-54 age group, decreasing thereafter The prevalence rate of invasive carcinoma increased with age. The prevalence pattern of CIN II was distinct from that of CIN III, but similar to that of CIN I. This would not have been observed if the Bethesda System had been used for cytological diagnosis. Mean age at time of CIN II diagnosis was about 10 years less than for CIN III diagnosis. Therefore, a high-grade lesion diagnosed in a young woman according to the Bethesda System would probably be a CIN II, whereas in an older woman it would probably be a CIN III.<br>O objetivo deste estudo foi estimar e analisar a prevalência das neoplasias intra-epiteliais cervicais (NIC) e do carcinoma invasivo do colo uterino, com base no diagnóstico citológico. Foram incluídas 120.635 mulheres que realizaram o exame citológico, entre setembro de 1998 a março de 1999, nos serviços públicos de saúde da região de Campinas, Brasil. As prevalências por 100 mil mulheres foram: 354 para NIC I; 255 para NIC II; 141 para NIC III e 24 de carcinoma invasivo. À medida que a idade aumentou, as prevalências e razões de prevalência diminuíram para NIC I e NIC II, e aumentaram para NIC III até 50-54 anos, decrescendo após. A prevalência do carcinoma invasivo aumentou com a idade. O padrão da prevalência da NIC II é distinto do padrão da NIC III e semelhante ao da NIC I, o que não teria sido observado se fosse utilizado o Sistema de Bethesda. Ainda, a média da idade ao diagnóstico da NIC II foi cerca de dez anos menor que para NIC III. Portanto, um diagnóstico de lesão de alto grau, de acordo com o Sistema de Bethesda, em uma mulher jovem provavelmente seria NIC II e em uma mulher mais velha seria NIC III

    Brazilian society of hepatology recommendations for the diagnosis and management of autoimmune diseases of the liver

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    ABSTRACT In order to draw evidence-based recommendations concerning the management of autoimmune diseases of the liver, the Brazilian Society of Hepatology has sponsored a single-topic meeting in October 18th, 2014 at São Paulo. An organizing committee comprised of seven investigators was previously elected by the Governing Board to organize the scientific agenda as well as to select twenty panelists to make a systematic review of the literature and to present topics related to the diagnosis and treatment of autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cirrhosis and their overlap syndromes. After the meeting, all panelists gathered together for the discussion of the topics and the elaboration of those recommendations. The text was subsequently submitted for suggestions and approval of all members of the Brazilian Society of Hepatology through its homepage. The present paper is the final version of the reviewed manuscript organized in topics, followed by the recommendations of the Brazilian Society of Hepatology

    Brazilian society of hepatology recommendations for the diagnosis and management of autoimmune diseases of the liver

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    ABSTRACT In order to draw evidence-based recommendations concerning the management of autoimmune diseases of the liver, the Brazilian Society of Hepatology has sponsored a single-topic meeting in October 18th, 2014 at São Paulo. An organizing committee comprised of seven investigators was previously elected by the Governing Board to organize the scientific agenda as well as to select twenty panelists to make a systematic review of the literature and to present topics related to the diagnosis and treatment of autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cirrhosis and their overlap syndromes. After the meeting, all panelists gathered together for the discussion of the topics and the elaboration of those recommendations. The text was subsequently submitted for suggestions and approval of all members of the Brazilian Society of Hepatology through its homepage. The present paper is the final version of the reviewed manuscript organized in topics, followed by the recommendations of the Brazilian Society of Hepatology

    Hepatocellular carcinoma recurrence after liver transplantation in a brazilian multicenter study : clinical profile and prognostic factors of survival

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    Liver transplantation (LT) is the treatment of choice for patients with unresectable early hepatocellular carcinoma (HCC). Post-LT HCC recurrence rates range from 8 to 20% and still impact on overall survival (OS). The aim of our study was to evaluate the impact of HCC recurrence on post-LT survival and analyze prognostic factors among those patients with recurrence. We carried out a national, multicenter, retrospective cohort study in Brazil. Medical records of 1119 LT recipients with HCC were collected. Data from patients with post-LT HCC recurrence were analyzed and correlated with post-relapse survival. OS of the 1119 patients included in the study was 63% over 5 years. Post-LT HCC recurrence occurred in 86 (8%) patients. The mean time to recurrence was 12 months. Sites of recurrence were extrahepatic in 55%, hepatic in 27%, and both hepatic and extrahepatic in 18%. Recurrence treatment was performed in 50 (64%) cases, mostly with sorafenib. Post-relapse survival rates were 34% at 1 year and 13% at 5 years. Univariable analysis identified alpha-fetoprotein more than 1000 ng/ml at relapse, recurrence treatment, extrahepatic location, and time to recurrence more than 2 years as prognostic factors. In multivariable analysis, recurrence treatment, extrahepatic location, and time to recurrence more than 2 years were independent predictors of better survival. In a large Brazilian cohort of LT recipients with HCC, post-LT HCC recurrence occurred in 8% and impacted significantly on the OS. Patients with early recurrence presented a worse prognosis. However, treatment of recurrence improved outcomes, highlighting the importance of early diagnosis3191148115

    Direct antiviral therapy for treatment of hepatitis C: A real-world study from Brazil

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    Introduction and objectives: Direct antiviral agents (DAAs) including sofosbuvir (SOF), daclatasvir (DCV), simeprevir (SIM) and ombitasvir, paritaprevir and dasabuvir were introduced 2015 in Brazil for treatment of hepatitis C virus (HCV) infection. The aims of this study were to assess effectiveness and safety of HCV treatment with DAA in real-life world in a highly admixed population from Brazil. Materials and methods: All Brazilian reference centers for HCV treatment were invited to take part in a web-based registry, prospectively conducted by the Brazilian Society of Hepatology, to assess outcomes of HCV treatment in Brazil with DAAs. Data to be collected included demographics, disease severity and comorbidities, genotype (GT), viral load, DAA regimens, treatment side effects and sustained virological response (SVR). Results: 3939 patients (60% males, mean age 58 ± 10 years) throughout the country were evaluated. Most had advanced fibrosis or cirrhosis, GT1 and were treated with SOF/DCV or SOF/SIM. Overall SVR rates were higher than 95%. Subjects with decompensated cirrhosis, GT2 and GT3 have lower SVR rates of 85%, 90% and 91%, respectively. Cirrhosis and decompensated cirrhosis in GT1 and male sex and decompensated cirrhosis in GT3 were significantly associated with no SVR. Adverse events (AD) and serious AD occurred in 18% and 5% of those subjects, respectively, but less than 1% of patients required treatment discontinuation. Conclusion: SOF-based DAA regimens are effective and safe in the heterogeneous highly admixed Brazilian population and could remain an option for HCV treatment at least in low-income countries
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