Methane dimer rovibrational states and Raman transition moments.

Benchmark-quality rovibrational data are reported for the methane dimer from variational nuclear motion computations using an ab initio intermolecular potential energy surface reported by [M. P. Metz et al., Phys. Chem. Chem. Phys., 2019, 21, 13504-13525]. A simple polarizability model is used to compute Raman transition moments that may be relevant for future direct observation of the intermolecular dynamics. Non-negligible ΔK ≠ 0 transition moments arise in this symmetric top system due to strong rovibrational couplings.

Vibrational infrared and Raman spectra of HCOOH from variational computations.

All vibrational energies of the formic acid molecule in different forms (trans-, cis-, delocalized-) were converged up to 4500 cm-1 beyond the zero-point vibrational energy with the GENIUSH-Smolyak variational approach and using an ab initio potential energy surface [D. P. Tew and W. Mizukami, J. Phys. Chem. A, 120, 9815-9828 (2016)]. The full-dimensional dipole and polarizability surfaces were fitted to points computed at the CCSD/aug-cc-pVTZ level of theory. Then, body-fixed vibrational dipole and polarizability transition moments were evaluated and used to simulate jet-cooled infrared and Raman spectra of HCOOH. The benchmark-quality vibrational energy, transition moment, and wave function data will be used in further work for comparison with vibrational experiments, and in further rovibrational computations.

Exact quantum dynamics developments for floppy molecular systems and complexes.

Molecular rotation, vibration, internal rotation, isomerization, tunneling, intermolecular dynamics of weakly and strongly interacting systems, intra-to-inter-molecular energy transfer, hindered rotation and hindered translation over surfaces are important types of molecular motions. Their fundamentally correct and detailed description can be obtained by solving the nuclear Schrödinger equation on a potential energy surface. Many of the chemically interesting processes involve quantum nuclear motions which are 'delocalized' over multiple potential energy wells. These 'large-amplitude' motions in addition to the high dimensionality of the vibrational problem represent challenges to the current (ro)vibrational methodology. A review of the quantum nuclear motion methodology is provided, current bottlenecks of solving the nuclear Schrödinger equation are identified, and solution strategies are reviewed. Technical details, computational results, and analysis of these results in terms of limiting models and spectroscopically relevant concepts are highlighted for selected numerical examples.

Temporary trend of breast cancer mortality in the state of Santa Catarina in the period from 1996 to 2019

Introduction: Breast cancer is the most common female cancer and the leading cause of cancer death in women around the world. It has repercussions not only on human health, but also on health services due to the high incidence resulting in a large number of consultations and treatments. The disease is responsible for a large demand for hospitalizations throughout Brazil, where an increase in mortality rates is observed and Santa Catarina does not differ from the national scenario. The study aimed to analyze the temporal trend of the breast cancer mortality rate in the state of Santa Catarina from 1996 to 2019 Methods: This is an ecological epidemiological study of time series of breast cancer mortality in the population residing in the state according to age groups and health macro-regions. Data were obtained from the Mortality Information System and the Brazilian Institute of Geography and Statistics. Simple linear regression of standardized mortality rates according to the world standard population was performed. p<0.05 was considered significant. Results: Data showed 9,637 deaths in the period. There was a significant upward trend in mortality in the state (from 6.50 to 7.92/100,000 women). An upward trend was observed in the age groups of 30­39 years, 60­69 years, and over 80 years. All seven health macro-regions showed an upward trend in mortality. Conclusion:The overall mortality rate from breast cancer in Santa Catarina showed a significant upward trend. A significant increase was also observed in the age groups of 30­39 years, 60­69 years, and 80 years old or older and in all health macro-regions. Problems in public health infrastructure, lack of control of risk factors and deficiency in mammographic screening are revealed. The elaboration and strengthening of public policies to control the disease are fundamental.

Germline genetic mutations in high-risk patients for breast cancer: profile of a group in the city of Florianopolis, Santa Catarina

To analyze the occurrence of genetic mutations in a sample of patients with high risk of breast cancer in Florianopolis/ SC from December 1st, 2021, to January 31, 2022. Methods: An observational, descriptive and retrospective study carried out through data collection of a preexisting database. A total of 194 tests were analyzed. Of these, 192 met the inclusion criteria and composed the final sample of 205 genes. Data were classified and reported the frequency and percentage of the variables: gene and presence or absence of mutation. Results: Mean age of the analyzed patients was 52.3 years, and most underwent the test due to personal history of breast cancer (80%). Clinical significance classification showed that, of the 192 gene panels, 62% were variants of uncertain significance; 14% were pathogenic; and 24%, negative. Of the 205 mutations, the most prevalent genes were: ATM 8.7%, MUTYH 5.8%, POLE 5.8%, BRCA2 4.8%, MSH6 4.8% and RECQL4 4.8%. Of the pathogenic tests regarding genetic predisposition to cancer (n=38/14.1%), the most common mutations were MUTYH (23%) and BRCA1 (15%), with mean age of 52 years (±14.3). In variants of uncertain significance panels (n=168/62%) the frequency rates were ATM (7.7%), POLE (7.1%) and MSH6 (5.9%) genes. The high penetrance genes were present in 18% of the genetic predisposition to cancer panels. Of those with positive family history (n=40), 19% of the genes were pathogenic, 53% were variants of uncertain significance; and 26% were negative. Furthermore, in patients with pathogenic mutations and positive family history (n=11), the most common mutations were in BRCA1 (27%) and BRCA2 (27%). Of the patients who tested due to personal history (n=152), 64% of the genes presented variants of uncertain significance, 13% were pathogenic and 22% were negative.

Performance of a black-box-type rovibrational method in comparison with a tailor-made approach: Case study for the methane-water dimer.

The present work intends to join and respond to the excellent and thoroughly documented rovibrational study of X. G. Wang and T. Carrington, Jr. [J. Chem. Phys. 154, 124112 (2021)] that used an approach tailored for floppy dimers with an analytic dimer Hamiltonian and a non-product basis set including Wigner D functions. It is shown in the present work that the GENIUSH black-box-type rovibrational method can approach the performance of the tailor-made computation for the example of the floppy methane-water dimer. Rovibrational transition energies and intensities are obtained in the black-box-type computation with a twice as large basis set and in excellent numerical agreement in comparison with the more efficient tailor-made approach.

Fingerprint region of the formic acid dimer: variational vibrational computations in curvilinear coordinates.

Curvilinear kinetic energy models are developed for variational nuclear motion computations including the inter- and the low-frequency intra-molecular degrees of freedom of the formic acid dimer. The coupling of the inter- and intra-molecular modes is studied by solving the vibrational Schrödinger equation for a series of vibrational models, from two up to ten active vibrational degrees of freedom by selecting various combinations of active modes and constrained coordinate values. Vibrational states, nodal assignment, and infrared vibrational intensity information is computed using the full-dimensional potential energy surface (PES) and electric dipole moment surface developed by Qu and Bowman [Phys. Chem. Chem. Phys., 2016, 18, 24835; J. Chem. Phys., 2018, 148, 241713]. Good results are obtained for several fundamental and combination bands in comparison with jet-cooled vibrational spectroscopy experiments, but the description of the ν8 and ν9 fundamental vibrations, which are close in energy and have the same symmetry, appears to be problematic. For further progress in comparison with experiment, the potential energy surface, and in particular, its multi-dimensional couplings representation, requires further improvement.

Implementation of the Surviving Sepsis Campaign in Patients With Heart Failure: Gender-Specific Outcomes.

Background Limited data exist about the impact of gender-specific outcomes in patients with heart failure (HF) who develop concomitant sepsis. Methods This is a retrospective cohort study of patients with HF who developed sepsis. Clinical outcomes, including in-hospital mortality, development of cardiogenic shock (CS), pulmonary edema requiring urgent intravenous diuretics (IVD), acute kidney injury (AKI), length of stay (LOS), and 30-day HF-related readmission, were evaluated in men vs. women. Results This cohort of 618 patients includes 272 (44%) women with a mean age of 75±14 years. Coronary artery disease (p<0.0001), diabetes mellitus (p=0.0213), stage ≥ 3 chronic kidney disease (p<0.0001), and HF with reduced ejection fraction (HFrEF) (p=0.0015) were more prevalent in men. The implementation of the Surviving Sepsis Campaign (i.e., intravenous (IV) crystalloids in the first six hours) was more aggressive in women (p=0.0192). There was no difference in in-hospital mortality (p=0.2385) between men and women. After adjusting for HF types, women with HF with preserved ejection fraction (HFpEF) developed more episodes of pulmonary edema requiring urgent IVD (p=0.0389), while men with HFpEF had more CS requiring inotropes (p=0.0400) and a longer LOS (p=0.0434). Conversely, women with HFrEF were most likely to develop CS requiring inotropes (p=0.0132). Conclusion Women with HF who developed sepsis receive a more aggressive implementation of the Surviving Sepsis Campaign than men, leading to more pulmonary edema events in women with HFpEF and more cardiogenic shock in women with HFrEF. A cautiously tailored approach is desperately needed for patients with HF who develop sepsis.

Exact quantum dynamics background of dispersion interactions: case study for CH4·Ar in full (12) dimensions.

A full-dimensional ab initio potential energy surface of spectroscopic quality is developed for the van-der-Waals complex of a methane molecule and an argon atom. Variational vibrational states are computed on this surface including all twelve (12) vibrational degrees of freedom of the methane-argon complex using the GENIUSH computer program and the Smolyak sparse grid method. The full-dimensional computations make it possible to study the fine details of the interaction and distortion effects and to make a direct assessment of the reduced-dimensionality models often used in the quantum dynamics study of weakly-bound complexes. A 12-dimensional (12D) vibrational computation including only a single harmonic oscillator basis function (9D) to describe the methane fragment (for which we use the ground-state effective structure as the reference structure) has a 0.40 cm-1 root-mean-square error (rms) with respect to the converged 12D bound-state excitation energies, which is less than half of the rms of the 3D model set up with the 〈r〉0 methane structure. Allowing 10 basis functions for the methane fragment in a 12D computation performs much better than the 3D models by reducing the rms of the bound state vibrational energies to 0.07 cm-1. The full-dimensional potential energy surface correctly describes the dissociation of the system, which together with further development of the variational (ro)vibrational methodology opens a route to the study of the role of dispersion forces in the excited methane vibrations and the energy transfer from the intra- to the intermolecular vibrational modes.

Full-dimensional (12D) variational vibrational states of CH4·F-: Interplay of anharmonicity and tunneling.

The complex of a methane molecule and a fluoride anion represents a 12-dimensional (12D), four-well vibrational problem with multiple large-amplitude motions, which has challenged the quantum dynamics community for years. The present work reports vibrational band origins and tunneling splittings obtained in a full-dimensional variational vibrational computation using the GENIUSH program and the Smolyak quadrature scheme. The converged 12D vibrational band origins and tunneling splittings confirm complementary aspects of the earlier full- and reduced-dimensionality studies: (1) the tunneling splittings are smaller than 0.02 cm-1; (2) a single-well treatment is not sufficient (except perhaps the zero-point vibration) due to a significant anharmonicity over the wells; and thus, (3) a full-dimensional treatment appears to be necessary. The present computations extend to a higher energy range than earlier work, show that the tunneling splittings increase upon vibrational excitation of the complex, and indicate non-negligible "heavy-atom" tunneling.

Toward breaking the curse of dimensionality in (ro)vibrational computations of molecular systems with multiple large-amplitude motions.

Methodological progress is reported in the challenging direction of a black-box-type variational solution of the (ro)vibrational Schrödinger equation applicable to floppy, polyatomic systems with multiple large-amplitude motions. This progress is achieved through the combination of (i) the numerical kinetic-energy operator (KEO) approach of Mátyus et al. [J. Chem. Phys. 130, 134112 (2009)] and (ii) the Smolyak nonproduct grid method of Avila and Carrington, Jr. [J. Chem. Phys. 131, 174103 (2009)]. The numerical representation of the KEO makes it possible to choose internal coordinates and a body-fixed frame best suited for the molecular system. The Smolyak scheme reduces the size of the direct-product grid representation by orders of magnitude, while retaining some of the useful features of it. As a result, multidimensional (ro)vibrational states are computed with system-adapted coordinates, a compact basis- and grid-representation, and an iterative eigensolver. Details of the methodological developments and the first numerical applications are presented for the CH4·Ar complex treated in full (12D) vibrational dimensionality.

Revisiting the Formation Mechanism of 1,3,4-Oxadiazole-2(3 H)-ones from Hydrazonyl Chloride and Carbon Dioxide.

The reaction mechanism for the synthesis of 1,3,4-oxadiazole-2(3 H)-ones from hydrazonyl chloride and CO2 in the presence of CsF/18-crown-6 and toluene, is revisited via density functional theory computations. Although this reaction was earlier classified as a 1,3-dipolar cycloaddition, we found some competing pathways involved therein. The mechanisms including the (F-CO2)- anion and the nitrile imine intermediate are some options. The dimerization of nitrile imine is another competing mechanism in this reaction. Our results show that the most favorable mechanism proceeds via a stepwise pathway without involving any nitrile imine intermediate or the (F-CO2)- anion. The F- anion, resulting from the formation of a complex between 18-crown-6 and Cs+ cation, deprotonates the nitrile imine precursor easily, which acts then as a nucleophilic anion, enhancing the reactivity of CO2 toward it. The mechanism for the reaction with COS, an isoelectronic analogue of CO2, is also explored.

Ab initio study of the CO-N2 complex: a new highly accurate intermolecular potential energy surface and rovibrational spectrum.

A new, highly accurate ab initio ground-state intermolecular potential-energy surface (IPES) for the CO-N2 complex is presented. Thousands of interaction energies calculated with the CCSD(T) method and Dunning's aug-cc-pVQZ basis set extended with midbond functions were fitted to an analytical function. The global minimum of the potential is characterized by an almost T-shaped structure and has an energy of -118.2 cm-1. The symmetry-adapted Lanczos algorithm was used to compute rovibrational energies (up to J = 20) on the new IPES. The RMSE with respect to experiment was found to be on the order of 0.038 cm-1 which confirms the very high accuracy of the potential. This level of agreement is among the best reported in the literature for weakly bound systems and considerably improves on those of previously published potentials.

Computing vibrational energy levels of CH4 with a Smolyak collocation method.

In this paper, we demonstrate that it is possible to apply collocation to compute vibrational energy levels of a five-atom molecule using an exact kinetic energy operator (with cross terms and coordinate-dependent coefficients). This is made possible by using (1) a pruned basis of products of univariate functions; (2) a Smolyak grid made from nested sequences of grids for each coordinate; (3) a collocation method that obviates the need to solve a generalized eigenvalue problem; (4) an efficient sequential transformation between the (nondirect product) grid and the (nondirect product) basis representations; and (5) hierarchical univariate functions that make it possible to avoid storing large intermediate vectors. The accuracy of the method is confirmed by computing 500 vibrational energy levels of methane.

Reducing the cost of using collocation to compute vibrational energy levels: Results for CH2NH.

In this paper, we improve the collocation method for computing vibrational spectra that was presented in the work of Avila and Carrington, Jr. [J. Chem. Phys. 143, 214108 (2015)]. Known quadrature and collocation methods using a Smolyak grid require storing intermediate vectors with more elements than points on the Smolyak grid. This is due to the fact that grid labels are constrained among themselves and basis labels are constrained among themselves. We show that by using the so-called hierarchical basis functions, one can significantly reduce the memory required. In this paper, the intermediate vectors have only as many elements as the Smolyak grid. The ideas are tested by computing energy levels of CH2NH.

Cryo-EM reconstruction of the Cafeteria roenbergensis virus capsid suggests novel assembly pathway for giant viruses.

Whereas the protein composition and overall shape of several giant virus capsids have been described, the mechanism by which these large capsids assemble remains enigmatic. Here, we present a reconstruction of the capsid of Cafeteria roenbergensis virus (CroV), one of the largest viruses analyzed by cryo-electron microscopy (cryo-EM) to date. The CroV capsid has a diameter of 3,000 Å and a Triangulation number of 499. Unlike related mimiviruses, the CroV capsid is not decorated with glycosylated surface fibers, but features 30 Å-long surface protrusions that are formed by loops of the major capsid protein. Based on the orientation of capsomers in the cryo-EM reconstruction, we propose that the capsids of CroV and related giant viruses are assembled by a newly conceived assembly pathway that initiates at a five-fold vertex and continuously proceeds outwards in a spiraling fashion.

A multi-dimensional Smolyak collocation method in curvilinear coordinates for computing vibrational spectra.

In this paper, we improve the collocation method for computing vibrational spectra that was presented in Avila and Carrington, Jr. [J. Chem. Phys. 139, 134114 (2013)]. Using an iterative eigensolver, energy levels and wavefunctions are determined from values of the potential on a Smolyak grid. The kinetic energy matrix-vector product is evaluated by transforming a vector labelled with (nondirect product) grid indices to a vector labelled by (nondirect product) basis indices. Both the transformation and application of the kinetic energy operator (KEO) scale favorably. Collocation facilitates dealing with complicated KEOs because it obviates the need to calculate integrals of coordinate dependent coefficients of differential operators. The ideas are tested by computing energy levels of HONO using a KEO in bond coordinates.

Using multi-dimensional Smolyak interpolation to make a sum-of-products potential.

We propose a new method for obtaining potential energy surfaces in sum-of-products (SOP) form. If the number of terms is small enough, a SOP potential surface significantly reduces the cost of quantum dynamics calculations by obviating the need to do multidimensional integrals by quadrature. The method is based on a Smolyak interpolation technique and uses polynomial-like or spectral basis functions and 1D Lagrange-type functions. When written in terms of the basis functions from which the Lagrange-type functions are built, the Smolyak interpolant has only a modest number of terms. The ideas are tested for HONO (nitrous acid).

Avaliação da resistência ao cisalhamento e miniflexão de resinas ortodônticas associadas ao primer / Evaluation of the shear bond and mini flexural strength of the orthodontics resins associated with primer

O objetivo desse estudo foi avaliar o efeito da aplicação do primer na resina na resistência ao cisalhamento e flexão em compósitos para colagem ortodôntica. Foram colados braquetes em 60 pré-molares humanos com as resinas Orthobond (G1), Z100 (G2) e Transbond XT (G3). Nos grupos 1, 2 e 3 a colagem foi feita de modo convencional, com a aplicação do primer na superfície condicionada. Nos grupos 4, 5 e 6 o primer foi aplicado na resina presente no braquete. Para o teste de flexão, nos grupos 1, 2 e 3 foram confeccionadas barras com as resinas Orthobond, Z100 e Transbond XT sem misturar com o primer. Nos grupos 4, 5 e 6 o primer foi aplicado nas resinas durante a confecção das barras. Os ensaios de resistência ao cisalhamento e flexão de três pontos foram realizados em máquina Instron com velocidade de 1,0 mm/minuto. Os resultados foram submetidos à Anova dois fatores e ao teste de Tukey (α=0,05). Os resultados mostraram que o Transbond XT apresentou resistência ao cisalhamento significativamente maior do que os outros materiais, e que não houve diferença significante quanto ao método de aplicação do primer. No teste de flexão, a resina Orthobond apresentou resistência significativamente menor do que os outros materiais, e a adição do primer reduziu significativamente a resistência à flexão dos materiais. Concluiu-se que a adição do primer na resina reduziu a resistência à flexão dos materiais e não alterou a resistência de união de braquetes ao esmalte. Dentre as resinas, o melhor desempenho foi apresentado pela Transbond XT...

The aim of this study was to evaluate the effect of primer application in shear bond and flexural strength of composite for orthodontic bonding. Brackets were bonded in 60 human premolars with Orthobond (G1), Z100 (G2) and Transbond XT (G3). In groups 1 to 3 the bond was done in a conventional manner with the application of the primer in the etched surface. In groups 4 to 6 the primer was applied on the primer resin in this bracket. For the flexural test, in groups 1-3 bars were made with the Orthobond, Z100 and Transbond XT without mixing with the primer. In groups 4 to 6 primer was applied to the resin during the manufacture of the bars. Shear bond test and flexural three points test were performed in Instron machine with a speed of 1.0 mm/minute. The results were submitted to Anova two factors and Tukey's test (α=0.05). The results showed that Transbond XT showed significantly higher shear bond resistance than the other materials; there was no significant difference in the primer application method. In the flexural test, the resin Orthobond showed significantly lower resistance than the other materials; adding the primer significantly reduced the flexural strength of the materials. It is concluded that the addition of the primer resin reduced the flexural strength of the material and did not alter the bond strength of brackets to enamel. Among the resins, the best performance was presented by Transbond XT...