Role of the Solvent and Intramolecular Hydrogen Bonds in the Antioxidative Mechanism of Prenylisoflavone from Leaves of Vatairea guianensis.

This work discusses the electron structure, antioxidative properties, and solvent contribution of two new antioxidant molecules discovered, named S10 and S11, extracted from a medicinal plant called Vatairea guianensis, found in the Amazon rain-forest. To gain a better understanding, a study using density functional theory coupled with the polarizable-continuum model and the standard 6-311++G(d,p) basis set was conducted. The results indicate that S10 has a higher antioxidant potential than S11, confirming the experimental expectations. In the gas phase, the hydrogen atom transfer route dominates the hydrogen scavenging procedure. However, in the water solvents, the antioxidant mechanism prefers the sequential proton loss electron transfer mechanism. Furthermore, the solvent plays a fundamental role in the antioxidant mechanism. The formation of an intramolecular OH···OCH3 hydrogen bond is crucial for accurately describing the hydrogen scavenging phenomenon, better aligning with the experimental data. The results suggest that the two isoflavones investigated are promising for the pharmacologic and food industries.

Biotransformation of 1-nitro-2-phenylethane [Formula: see text] 2-phenylethanol from fungi species of the Amazon biome: an experimental and theoretical analysis.

CONTEXT: Natural products and their biotransformation procedures are a powerful source of new chromophores with potential applications in fields like biology, pharmacology and materials science. Thus, this work discusses about the extraction procedure of 1-nitro-2-phenylethane (1N2PE) from Aniba canelilla, its biotransformation setup into 2-phenylethanol (2PE) using four fungi, Lasiodiplodia caatinguensis (phytopathogenic fungus from Citrus sinensis), Colletotrichum sp. (phytopathogenic fungus from Euterpe oleracea), Aspergillus flavus and Rigidoporus lineatus isolated from copper mining waste located in the interior of the Brazilian Amazon. A detailed experimental and theoretical vibrational analysis (IR and Raman) have allowed us to perform some charge transfer effects on the title compounds (push-pull effect) by monitoring specific vibrational modes of their electrophilic and nucleophilic molecular sites. The solvent interactions promote molecular conformations that affect the vibrational spectra of the donor and acceptor groups, as can be seen comparatively in the gas and aqueous solution spectra, an effect possibly related to the bathochromic shift in the calculated optical spectrum of the compounds. The nonlinear optical behavior shows that while the solvent reduces the response of 1N2PE, the response of 2PE increases the optical parameters, which presents low refractive index (n) and first hyperpolarizability. ([Formula: see text]) is almost eight times that reported for urea (42.79 a.u.), a common nonlinear optical material. Furthermore, the bioconversion goes from an electrophilic to a nucleophilic compound, affecting its molecular reactivity. METHODS: 1N2PE was obtained from Aniba canelilla, whose essential oil is constituted of [Formula: see text] of 2PE. The A. canelilla essential oil was extracted under hydrodistillation. The biotransformation reactions were performed in autoclaved liquid media (100 mL) composed of malt extract (2%) in 250 mL Erlenmeyer flask. Each culture was incubated in an orbital shaker (130 rpm) at [Formula: see text]C during 7 days and after that, 50 mg of 1N2PE (80%) were diluted in 100 [Formula: see text]L of dimethylsulfoxide (DMSO) and added to the reactions flasks. Aliquots (2 mL) were removed using ethyl acetate (2 mL) and analyzed by GC-MS (fused silica capillary col1umn, Rtx -5MS 30 m [Formula: see text] 0.25 mm [Formula: see text] 0.25 [Formula: see text]m) in order to determine the amount of 1N2PE biotransformation. FTIR 1N2PE and 2PE spectra were obtained by attenuated total reflectance (ATR), using a Agilent CARY 630 spectrometer, in the spectral region 4000-650 cm[Formula: see text]. The quantum chemical calculations were carried out in the Gaussian 09 program while the DICE code was used to perform the classical Monte Carlo simulations and generate the liquid environment using the classical All-Atom Optimized parameters for Liquid Simulations (AA-OPLS). All nonlinear optical properties, reactive parameters, and electronic excitations were calculated using the Density Functional Theory framework coupled to the standard 6-311++G(d,p) basis set.

The Solute Polarization and Structural Effects on the Nonlinear Optical Response of Based Chromone Molecules.

The solute polarization due to solvent is a an electrostatic quantum effect that impacts diverse molecular properties, including the nonlinear optical response of a material. An iterative procedure that allows updating the solute charge distribution in the presence of the solvent is combined with a sequential Monte Carlo/Quantum Mechanics methodology and Density Functional Theory methods to evaluate the nonlinear optical (NLO) response using the hyper Rayleigh scattering (HRS) of a series of chromones recently identified in Chamaecrista diphylla, an herbaceous plant abundant throughout the Americas and used in folk medicine. From this study, it is determined that from gas to solvent environment, the systems acquire low refractive index (n) and an improvement of the first hyperpolarizability (ßHRS ), signaling potential NLO uses. It is shown that the octupolar contributions (ßJ=3 ) superate the dipolar ones (ßJ=1 ) and dominate the second-order optical response in both gas and liquid phases, which indicate nontrivial optical materials. Moreover, the solvent environment and structural changes in the periphery can tune significantly the dipolar/octupolar balance, showing a key to control the decoupling between these contributions.

The Importance of the Density Functional Theory Exchange-Correlation Hartree-Fock Term in Magnetic Resonance: Application to an Aqueous Environment.

Within the framework of Density Functional Theory (DFT), the relevance of the term Hartree-Fock exchange (HFE) for a variety of molecular properties is a critical point. For this reason, we spend efforts to understand these relationships in nuclear magnetic resonance (NMR) parameters in a water solvent. This work takes advantage of the appropriate aug-cc-pVTZ-J basis set and the Minnesota family of DFT methods, which consider different portions of HFE contributions. With regard to solvent participation, the results are based on a sequential Monte Carlo/Quantum Mechanics procedure, which builds the structures of the liquid under realistic thermodynamic conditions. Compared to the accurate results of second-order polarization propagator approximation (SOPPA) and experimental data, all NMR parameters show a huge dependence on the size of the HFE contribution. For instance, the inclusion of this term in 1JOH and 2JHH indirect spin-spin couplings does vary with 49.661 and 25.459 Hz, respectively. The M06-HF method accounts for 100% of HFE and better matches the σO and σH shielding constants. On the other hand, 1JOH and 2JHH demand a medium contribution (54% of HFE), the best description being associated with the M06-2X method. Thus, the dependence varies regarding the phenomenology of the property in focus and the order for independent treatments. For elements that participate in hydrogen bonds simultaneously as donor and acceptor actors, the results indicate that explicit solvent molecules must be considered in the quantum mechanical calculations for better modeling of paramagnetic shielding constants.

Anthelmintic resistance against gastrointestinal nematodes in beef cattle: effect on liveweight gain of grazing livestock in Mexico / Resistência anti-helmíntica em nematódeos gastrointestinais de bovinos de corte em uma região tropical: efeito no ganho de peso vivo do gado de pasto no México

This study aimed to determine the efficacy and parasite resistance of levamisole (LV) and ivermectin (IVM) in beef cattle naturally infected with gastrointestinal nematodes, as well as the effect on the liveweight gain in a tropical wet region of Oaxaca, Mexico. From November 2019 to January 2020, sixty-six grazing calves were randomly allocated into three groups of twenty-two animals each, treated with LV or IVM or an untreated control group (day 0). Feces were collected 1 day before treatment and 15 days after treatment. The liveweight gain from each animal was recorded at days 0, 15, 30 and 45 post treatment. The LV group presented the highest reduction of eggs per gram (EPG) of feces, followed by the IVM group. Resistance to IVM was detected, although LV resistance was also suspected. The IVM group had significantly higher effective treatment at 93.5%, resulting in an increase (P<0.05) of liveweight gain of 16.1kg, followed by the LV group (92.4%) with 17.1kg, compared to the untreated control group. A significant (P < 0.05) negative correlation was observed between EPG and weight gain for the LV (r = -0.46) and IVM groups (r = -0.32). LV and IVM showed a lack of efficacy against gastrointestinal nematodes, as well as an adequate capacity for EPG reduction but with IVM resistance and detrimental effects on growth performance in grazing beef cattle.

Os nematódeos gastrointestinais do gado de pastoreio causam perdas econômicas substanciais em todo o mundo. Este estudo teve como objetivo determinar a eficácia e a resistência parasitária do levamisol (LV) e da ivermectina (IVM) em bovinos de corte naturalmente infectados com nematódeos gastrointestinais, bem como o efeito no ganho de peso vivo, em uma região tropical úmida de Oaxaca, México. De novembro de 2019 a janeiro de 2020, 66 bezerros de pasto foram distribuídos aleatoriamente em três grupos de 22 animais cada um, tratados com LV ou IVM, ou em um grupo controle sem tratamento (dia 0). As fezes foram coletadas 1 dia antes do tratamento e 15 dias após o tratamento. O ganho de peso vivo de cada animal foi registrado nos dias 0, 15, 30 e 45 pós-tratamento. O grupo do LV apresentou a maior redução de ovos por grama de fezes (EPG), seguido pelo grupo IVM. A resistência à IVM foi detectada, embora também se suspeitasse de resistência ao LV. O grupo IVM teve um tratamento eficaz significativamente maior, com 93,5%, resultando em um aumento (P < 0,05) do ganho de peso vivo de 16,1kg, seguido pelo grupo LV (92,4%), com 17,1kg, em comparação com o grupo controle sem tratamento. Foi observada uma correlação negativa (P < 0,05) entre o EPG e o ganho de peso para os grupos LV (r = -0,46) e IVM (r = -0,32). LV e IVM mostraram falta de eficácia contra nematódeos gastrointestinais, assim como uma capacidade adequada de redução de EPG, mas com resistência IVM e efeitos prejudiciais no desempenho de crescimento em gado de corte em pastagem.

Complex gastroschisis with apple peel jejunoileal atresia, primary closure, and Santulli procedure as a surgical alternative. Case report.

BACKGROUND: Gastroschisis is a closure defect of the abdominal wall classified as complex when it presents with necrosis, volvulus, or atresia of the gastrointestinal tract. Jejunoileal atresia is caused by abnormal closure, discontinuity, or narrowing of the intestine. Apple Peel or type IIIb is the rarest presentation, with an incidence of 1.3 per 10,000 live births. In addition to presenting a high mortality rate. PRESENTATION OF CASE: We present a preterm newborn patient of 30 weeks with a diagnosis of gastroschisis and jejunoileal atresia type IIIB. The congenital wall defect was closed in the first surgical stage, and he was then taken at four weeks to correct the atresia. In the second surgery, we found a difference in intestinal calibers of 8:1, and the surgical team decides to perform remodeling of the proximal sac with a mechanical stapler and perform anastomosis using the Santulli technique. On day 6 of life, enteral feeding began through a nutrition tube localized under intestinal anastomosis with progressive nutritional increase. Subsequently, intermittent and progressive occlusion of the stoma was performed, leading the patient to a definitive surgical closure one month later. CONCLUSIONS: The mortality rate for gastroschisis and complex intestinal atresia is high. Advances in prenatal diagnosis, neonatal intensive care, and proper surgical correction are crucial to improving survival rates. The Santulli procedure is a surgical alternative for intestinal atresias with a caliber discrepancy greater than 4 to 1 or when the characteristics of the distal part do not allow a primary anastomosis to be performed.

Physical achirality in geometrically chiral rotamers of hydrazine and boranylborane molecules.

The diagonal components and the trace of tensors which account for chiroptical response of the hydrazine molecule N2 H4 , that is, static anapole magnetizability and frequency-dependent electric dipole-magnetic dipole polarisability, are a function of the ϕ ≡ ∠ H─N─N─H dihedral angle. They vanish for symmetry reasons at ϕ = 0° and ϕ = 180°, corresponding respectively to C2v and C2h point group symmetries, that is, cis and trans conformers characterized by the presence of molecular symmetry planes. Nonetheless, vanishing diagonal components have been observed also in the proximity of ∠ H─N─N─H = 90°, in which the point group symmetry is C2 and hydrazine is unquestionably chiral. In the boranylborane molecule B2 H4 , assuming the B─B bond in the y direction, the ayy component of the anapole magnetizability tensor approximately vanishes for dihedral angles ∠ H─B─B─H corresponding to chiral rotamers which belong to D2 symmetry. Such anomalous effects have been ascribed to physical achirality of these conformers, that is, to their inability to sustain electronic current densities inducing either anapole moments, or electric and magnetic dipole moments, about the chiral axis connecting heavier atoms, as well as perpendicular directions. In other terms, the structure of certain geometrically chiral rotamers may be such that neither toroidal nor helical flow, which determine chiroptical phenomenology, can take place in the presence of perturbing fields parallel or orthogonal to the chiral axis.

A Density Functional Theory Study of Optical Rotation in Some Aziridine and Oxirane Derivatives.

We present time-dependent density functional theory (TDDFT) calculations of the electronic optical rotation (ORP) for seven oxirane and two aziridine derivatives in the gas phase and in solution and compare the results with the available experimental values. For seven of the studied molecules it is the first time that their optical rotation was studied theoretically and we have therefore investigated the influence of several settings in the TDDFT calculations on the results. This includes the choice of the one-electron basis set, the exchange-correlation functional or the particular polarizable continuum model (PCM). We can confirm that polarized quadruple zeta basis sets augmented with diffuse functions are necessary for converged results and find that the aug-pc-3 basis set is a viable alternative to the frequently employed aug-cc-pVQZ basis set. Based on our study, we cannot recommend the generalized gradient functional KT3 for calculations of the ORP in these compounds, whereas the hybrid functional PBE0 gives results quite similar to the long-range correct CAM-B3LYP functional. Finally, we observe large differences in the solvent effects predicted by the integral equation formalism of PCM and the SMD variant of PCM. For the majority of solute/solvent combinations in this study, we find that the SMD model in combination with the PBE0 functional and the aug-pc-3 basis set gives the best agreement with the experimental values.

Ecological and phylogenetic determinants of life-history patterns among ten loricariid species.

We analysed the influence of ecological factors, phylogenetic history and trade-offs between traits on the life-history variation among 10 loricariid species of the middle Paraná River. We measured eight life-history variables and classified the life-history strategies following the equilibrium-periodic-opportunistic (EPO) model. Principal-component analysis of life-history traits segregated species along a gradient from small opportunistic (low fecundity, low parental investment) to large equilibrium (low-medium fecundity, high parental investment) species. A clear periodic strategist was absent in the analysed assemblage. Variation partitioning by canonical phylogenetic ordination analysis showed both a component of variation uniquely explained by phylogenetic history (PH; 32.2%) and a component shared between PH and ecological factors (EF; 37%). The EPO model is a useful tool for predicting correlations among life-history traits and understanding potential demographic responses of species to environmental variation. Life-history patterns observed throughout Loricariidae suggests that this family has diversified across all three endpoint strategies of the EPO model. Our study indicates that evolutionary lineage affiliation at the level of subfamily can be a strong predictor of the life-history strategy used by each species.

Periductal Lymphocytic Infiltrate at Bilary Atresia Diagnosis Increases the Risk of Addition to the Transplant Waitlist.

PURPOSE: Biliary atresia (BA) is the main indication for pediatric liver transplantation. The aim of this study is to correlate aspects of histological examinations of diagnostic hepatic biopsies for BA with the patients' clinical progression and successful addition to the liver transplant waitlist. METHODS: This was a retrospective study of all 108 BA cases treated at the Federal University of São Paulo (1998-2015). Demographic and clinical data were correlated with histological findings. A logistic regression was used for outcome analysis, while the Kaplan-Meier method was applied for survival analysis. RESULTS: There were 108 patients with BA, 68.5% of whom underwent Kasai surgery. Patients added to the transplant waitlist tended to undergo Kasai surgery at a later time (P = .035). Periductal lymphocytic infiltrate was correlated with the addition to the transplant waitlist, with an odds ratio of 3.92 (P = .033). Patients who developed ascites after surgery were more frequently added to the transplant waitlist (P = .05). CONCLUSION: Patients added to the transplant waitlist underwent Kasai surgery later than other patients. Periductal lymphocytic infiltrate in the diagnostic hepatic biopsy and ascites after Kasai surgery were associated with an increased likelihood of addition to the transplant waitlist.

Colonic perforation due to amebiasis, a rare and lethal complication.

Amebiasis is still a major healthcare concern, especially in developing countries like Ecuador. The lack of sanitary control and hygiene measures make parasites infections still a burden for patients and physicians. Despite infections due to this parasites are usually mild, severe infections and fatal outcomes although rare still occur. Bowel perforation is a rare complication of amebiasis, and unfortunately, it continues to be almost fatal. We present a case of an Ecuadorian patient who presented to the emergency room with an acute abdomen, despite adequate surgery and critical care, the patient regrettably died. Bowel perforation due to Entamoeba histolytica was the final diagnosis.

Cirugía Plástica: ¿Enseñar y aprender o aprender a enseñar? / Plastic Surgery: Teach and learn or learn to teach?

Ser especialista certificado en Cirugía Plástica es esencial. Gran cantidad de maestros enseñan muy bien, simplemente sirviendo como ejemplo. Si bien este hecho ha logrado grandes discípulos, la aplicación de un planeamiento basado en las ciencias de la educación puede mejorar mucho más el producto final. La educación médica va mucho más allá de excelentes clases magistrales con herramientas multimedia. Abarca desde un correcto planeamiento educativo inicial hasta la evaluación continua como retroalimentación del sistema educativo. Incluye la interpretación científica del proceso de enseñanza-aprendizaje y de los aspectos lógicos, fisiológicos, sociológicos y psicológicos de la relación docente / alumno. Ser docente en medicina implica manejar una serie de variables que sobrepasan el deseo de enseñar. Ser docente en medicina es capacitarse adecuadamente en educación; es aprender a aprender y aprender a enseñar. La intención del artículo es introducir conceptos sobre ciencias de la educación que correctamente aplicados a la medicina permitan reflexionar sobre el actual modelo de enseñanza y de esta manera mejorar lo que cada educador ya está haciendo con loable vocación

There is no doubt that to be a plastic surgery board certified specialist is essential. Many professors teach in a very good way, simply based on being an example to be followed. The acquisition of surgical dexterity is part of a good surgery and must be one of the main objectives in residents' training. Even though this approach has got excellent students, education sciences based planning, can improve much more the final product. Medical education goes beyond excellent lectures with multimedia effects. It implies from initial planning to continuing evaluation as a feedback educational process. It includes many variables that go beyond teaching vocation. To be a medical teacher is to properly learn the educational process. To be a medical teacher is to learn how to learn in order to learn how to teach. The objective of this article is to introduce basic concepts in educational sciences that properly applied to medicine teaching allow to think it over on the present teaching model. Following this idea, it will be possible to improve what every educator with commendable vocation already is performing.

Computational study of basis set and electron correlation effects on anapole magnetizabilities of chiral molecules.

In the presence of a static, nonhomogeneous magnetic field, represented by the axial vector B at the origin of the coordinate system and by the polar vector C=∇×B, assumed to be spatially uniform, the chiral molecules investigated in this paper carry an orbital electronic anapole, described by the polar vector A. The electronic interaction energy of these molecules in nonordered media is a cross term, coupling B and C via a¯, one third of the trace of the anapole magnetizability aαß tensor, that is, WBC=-a¯B·C. Both A and W(BC) have opposite sign in the two enantiomeric forms, a fact quite remarkable from the conceptual point of view. The magnitude of a¯ predicted in the present computational investigation for five chiral molecules is very small and significantly biased by electron correlation contributions, estimated at the density functional level via three different functionals. © 2016 Wiley Periodicals, Inc.

Investigation of the resonance-assisted hydrogen bond in model ß-diketones through localized molecular orbital analysis of the spin-spin coupling constants related to the O-H···O hydrogen bond.

The resonance-assisted hydrogen bond (HB) phenomenon has been studied theoretically by a localized molecular orbital (LMO) decomposition of the spin-spin coupling constants between atoms either involved or close to the O-H···O system of some ß-diketones and their saturated counterparts. The analysis, carried out at the level of the second-order polarization propagator approximation, shows that the contributions in terms of LMO to the paramagnetic spin orbital and the spin dipolar Ramsey terms proof the importance of the delocalized π-electron structure supporting the idea of the existence of the resonance-assisted HB phenomenon phenomenon. The LMO contributions to the Fermi contact term indicate mainly the presence of the HB that may or not be linked to the π-electrons.

On the truncation of the number of excited states in density functional theory sum-over-states calculations of indirect spin spin coupling constants.

It is investigated, whether the number of excited (pseudo)states can be truncated in the sum-over-states expression for indirect spin-spin coupling constants (SSCCs), which is used in the Contributions from Localized Orbitals within the Polarization Propagator Approach and Inner Projections of the Polarization Propagator (IPPP-CLOPPA) approach to analyzing SSCCs in terms of localized orbitals. As a test set we have studied the nine simple compounds, CH4, NH3, H2O, SiH4, PH3, SH2, C2H2, C2H4, and C2H6. The excited (pseudo)states were obtained from time-dependent density functional theory (TD-DFT) calculations with the B3LYP exchange-correlation functional and the specialized core-property basis set, aug-cc-pVTZ-J. We investigated both how the calculated coupling constants depend on the number of (pseudo)states included in the summation and whether the summation can be truncated in a systematic way at a smaller number of states and extrapolated to the total number of (pseudo)states for the given one-electron basis set. We find that this is possible and that for some of the couplings it is sufficient to include only about 30% of the excited (pseudo)states.

Reflexiones sobre educación médica / Reflections on medical education

Con los avances diarios de la medicina, los educadores se han dado cuenta que el método de memorizar datos y hechos, no es la mejor manera de aprender. Además de la idoneidad profesional de los docentes, es necesario que se capaciten en la manera de enseñar, siguiendo pautas pedagógicas. El currículo basado en competencias puede ser la respuesta. Se trata de un concepto curricular diseñado para capacitar al médico en las habilidades y destrezas que necesita, más que gran cantidad de conocimientos médicos, cuidados del paciente, destrezas manuales, profesionalismo y habilidades de comunicación. Las facultades de medicina y los programas de residencias, definen las habilidades y destrezas que las necesidades de los pacientes y de la sociedad, que consisten en conocimientos. El currículo basado en competencias se focaliza en lo que el médico debe ser capaz de hacer y sentir. Las estrategias de enseñanza para este abordaje, tienden a dar menos tiempo a las clases magistrales y difíciles exámenes para dar paso a seminarios, aprendizaje clínico basado en experiencias y evaluación continua, incluyen- do revisión de pares. El compromiso del cuerpo docente es el primer paso para cambiar la enseñanza. En el caso de enseñanza basada en competencias, los profesores finalmente deberán aprender a integran una gran variedad de materiales provenientes de diferentes campos, incluyendo aprendizaje de pedagogía. En Argentina, la Ley Nacional de Educación enfatiza la necesidad de profesores mejor preparados, comprometidos en aprender a aprender, para aprender a enseñar

With new medical and scientific knowledge coming to light each day, medical educators realize that memorizing specific lists of data and facts is no longer the ideal way to learn. Besides having medical expertise, it is very important to know how to teach and how to be prepared following pedagogical concepts. Competency-based medical education may be the answer. It is a curricular concept designed to provide the skills physicians need, rather than solely a large amount of knowledge. A medical school or residency program using the mentioned approach defines a set of competencies based on society and patient needs, such as medical knowledge, patient care, manual skills, professionalism and communicational abilities. Competency-based medical education focuses on what a physician should actually be able to do and to feel. Teaching methods for this approach tend to give less time to larger lecture courses and intense examinations, for more time to seminars, group discussions, active clinical learning experiences, and ongoing formative assessment including peer review. Faculty engagement is, of course, the first step to any change in an approach to training. In the case of competency-based education, professors ultimately will need to learn how to integrate a variety of materials from several different fields, including pedagogical learning. Argentina's Education Law, reinforces the need of better prepared professors, eager to learn to learn, to be able to learn to teach

Os avanços diários da medicina, levaram os educadores à percepção de que o método de memorizar dados e fatos, não é a melhor maneira de apreender. Além do saber profissional dos docentes, é necessário que se aperfeiçõem nas técnicas do ensino, seguindo linhas pedagógicas. O currículo baseado em competências pode ser a resposta. Trata-se de um conceito curricular desenhado para capacitar o médico nas habilidades e destrezas que necessita. Mais do que na grande quantidade de conhecimentos médicos, nos cuidados do paciente, destrezas manuais, profissionalismo e habilidades de comunicação. As escolas de Medicina e os programas de práticas hospitalares, definem as habilidades e destrezas para atender as necessidades dos pacientes e da sociedade através de conhecimentos. O currículo baseado em competências focaliza aquilo que o médico deve ser capaz de fazer e sentir. As estratégias de ensino para esta abordagem, se orientam menos ao tempo das aulas magistrais e a difíceis exames e mais aos seminários, à aprendizagem clínica baseada na experiência e na avaliação continua, incluindo a revisão dos pares. O compromisso do corpo docente é o primeiro passo para mudar o ensino. No caso daquele que está baseado em competências, os professores finalmente deverão apreender a integrar una grande variedade de materiais provenientes de diferentes campos, incluindo aprendizagem da Pedagogia. Na Argentina, a Lei Nacional de Educação enfatiza a necessidade de professores melhor preparados, comprometidos em aprender a apreender, para aprender a ensinar

Communication: Localized molecular orbital analysis of the effect of electron correlation on the anomalous isotope effect in the NMR spin-spin coupling constant in methane.

We discuss the effect of electron correlation on the unexpected differential sensitivity (UDS) in the (1)J(C-H) coupling constant of CH4 using a decomposition into contributions from localized molecular orbitals and compare with the (1)J(N-H) coupling constant in NH3. In particular, we discuss the well known fact that uncorrelated coupled Hartree-Fock (CHF) calculations are not able to reproduce the UDS in methane. For this purpose we have implemented for the first time a localized molecular orbital analysis for the second order polarization propagator approximation with coupled cluster singles and doubles amplitudes--SOPPA(CCSD) in the DALTON program. Comparing the changes in the localized orbital contributions at the correlated SOPPA and SOPPA(CCSD) levels and at the uncorrelated CHF level, we find that the latter overestimates the effect of stretching the bond between the coupled atoms on the contribution to the coupling from the localized bonding orbital between these atoms. This disturbs the subtle balance between the molecular orbital contributions, which lead to the UDS in methane.

Grade IV fibrosis interferes in biliary drainage after Kasai procedure.

OBJECTIVES: Biliary atresia (BA) is the most common cause of liver transplantation in children. The earlier the treatment is done, the better the prognosis. The aim is to evaluate the impact of late diagnosis in children with BA, including the histopathological findings and success rate of biliary drainage in patients submitted to hepatic portoenterostomy (HPE). MATERIALS AND METHODS: A retrospective study of cases of BA in the Department of Pediatric Surgery, Federal University of São Paulo (UNIFESP) between 1998-2011. We found 63 cases of BA; of these, 42 underwent HPE and 21 were referred for liver transplantation. Clinic and pathologic data were evaluated. RESULTS: The HPE was performed with a mean age of 86.5 days, with 16.6% having the operation at 60 days or earlier; 59.2% between 61 and 90 days; and 23.8% after 90 days. Successful biliary drainage occurred in 31% of surgeries, Mean days when HPE drained was 69.1 days, and 94.3 days when the surgery did not drain (P = .05). All patients who were successfully drained, did not have grade IV fibrosis on histology. In cases in which surgery was performed after 60 days that had not drained, 25% had grade IV fibrosis on biopsy (P = .0469). CONCLUSION: The age of HPE relates to better prognosis of the disease. It was found that the rate of grade IV fibrosis is higher in no drainage patients. All patients with grade IV fibrosis had no biliary drainage.

Monte Carlo-quantum mechanics study of magnetic properties of hydrogen peroxide in liquid water.

A theoretical study of magnetic properties of hydrogen peroxide in water has been carried out by means of Monte Carlo simulation and quantum mechanics calculations. The solvent effects were evaluated in supermolecular structures generated by simulations in the NPT ensemble. The solute-solvent structure was analyzed in terms of radial distribution functions, and the solute-solvent hydrogen bonds were identified with geometric and energetic criteria. Approximately three water molecules are hydrogen bonded to H2O2 (0.6 and 0.8 in each hydrogen and oxygen atom, respectively, of the H2O2). Although, on average, both hydroxyls of the peroxide are equivalent, the distribution of hydrogen-bonded water molecules is highly asymmetric. Analyzing the statistics of the hydrogen bonds, we identify that only 34% of the configurations give symmetric distributions around the two hydroxyls of the H2O2 simultaneously. The magnetic shieldings and the indirect spin-spin coupling constants were calculated at the B3LYP/aug-cc-pVTZ and aug-cc-pVTZ-J computational level. We find that the solvent shields the oxygen and unshields the hydrogen atoms of the peroxide (+5.5 and -2.9 ppm, respectively), with large fluctuation from configuration to configuration in the oxygen case, an effect largely accounted for in terms of a single hydrogen bond with H2O2 as the proton donor. The most sensitive coupling in the presence of the solvent is observed to be the one-bond J(O,H).