256 research outputs found
Predicting Beta Decay Energy with Machine Learning
represents one of the most important factors characterizing
unstable nuclei, as it can lead to a better understanding of nuclei behavior
and the origin of heavy atoms. Recently, machine learning methods have been
shown to be a powerful tool to increase accuracy in the prediction of diverse
atomic properties such as energies, atomic charges, volumes, among others.
Nonetheless, these methods are often used as a black box not allowing
unraveling insights into the phenomena under analysis. Here, the
state-of-the-art precision of the -decay energy on experimental data is
outperformed by means of an ensemble of machine-learning models. The
explainability tools implemented to eliminate the black box concern allowed to
identify uncertainty and atomic number as the most relevant characteristics to
predict energies. Furthermore, physics-informed feature addition
improved models' robustness and raised vital characteristics of theoretical
models of the nuclear structure
The Bose–Hubbard model with squeezed dissipation
The stationary properties of the Bose–Hubbard model under squeezed dissipation are investigated. The dissipative model does not possess aU (1) symmetry but conserves parity. We find that 〈a j 〉 = 0 always holds, so no symmetry breaking occurs. Without the onsite repulsion, the linear case is known to be critical. At the critical point the system freezes to an EPR state with infinite two mode entanglement. We show here that the correlations are rapidly destroyed whenever the repulsion is switched on. As we increase the latter, the system approaches a thermal state with an effective temperature defined in terms of the squeezing parameter in the dissipators. We characterize this transition by means of a Gutzwiller ansatz and the Gaussian Hartree–Fock–Bogoliubov approximation
AR/ER Ratio Correlates with Expression of Proliferation Markers and with Distinct Subset of Breast Tumors
The co-expression of androgen (AR) and estrogen (ER) receptors, in terms of higher AR/ER ratio, has been recently associated with poor outcome in ER-positive (ER+) breast cancer (BC) patients. The aim of this study was to analyze if the biological aggressiveness, underlined in ER+ BC tumors with higher AR/ER ratio, could be due to higher expression of genes related to cell proliferation. On a cohort of 47 ER+ BC patients, the AR/ER ratio was assessed by immunohistochemistry and by mRNA analysis. The expression level of five gene proliferation markers was defined through TaqMan®-qPCR assays. Results were validated using 979 BC cases obtained from gene expression public databases. ER+ BC tumors with ratios of AR/ER ≥ 2 have higher expression levels of cellular proliferation genes than tumors with ratios of AR/ER < 2, in both the 47 ER+ BC patients (P < 0.001) and in the validation cohort (P = 0.005). Moreover, BC cases with ratios of AR/ER ≥ 2 of the validation cohort were mainly assigned to luminal B and HER2-enriched molecular subtypes, typically characterized by higher proliferation and poorer prognosis. These data suggest that joint routine evaluation of AR and ER expression may identify a unique subset of tumors, which show higher levels of cellular proliferation and therefore a more aggressive behavior
Architecting new diffraction-resistant light structures and their possible applications in atom guidance
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOIn this work we extend the so called frozen wave method in order to obtain new diffraction resistant light structures that can be shaped on demand, with possible applications in atom guidance. The resulting beams and the corresponding optical dipole potentials exhibit a strong resistance to diffraction effects and their longitudinal and transverse intensity patterns can be chosen a priori. Besides the theoretical development, we also present the experimental confirmation of our approach; specifically, by generating three different beam profiles using a spatial light modulator that is addressed by a computer-generated hologram. In addition to its many potential applications in atom guiding, the method developed here can also lead to many new developments in optics and photonics in general. (C) 2016 Optical Society of AmericaIn this work we extend the so called frozen wave method in order to obtain new diffraction resistant light structures that can be shaped on demand, with possible applications in atom guidance. The resulting beams and the corresponding optical dipole potentials exhibit a strong resistance to diffraction effects and their longitudinal and transverse intensity patterns can be chosen a priori. Besides the theoretical development, we also present the experimental confirmation of our approach, specifically, by generating three different beam profiles using a spatial light modulator that is addressed by a computer-generated hologram. In addition to its many potential applications in atom guiding, the method developed here can also lead to many new developments in optics and photonics in general.24222540325408CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO141977/2013-2, 312376/2013-82015/26444-
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DNA cleavage and antitumour activity of platinum(II) and copper(II) compounds derived from 4-methyl-2-N-(2-pyridylmethyl)aminophenol: spectroscopic, electrochemical and biological investigation
The reaction of the redox-active ligand, Hpyramol (4-methyl-2-N-(2-pyridylmethyl)aminophenol) with K2PtCl4 yields monofunctional square-planar [Pt(pyrimol)Cl], PtL-Cl, which was structurally characterised by single-crystal X-ray diffraction and NMR spectroscopy. This compound unexpectedly cleaves supercoiled double-stranded DNA stoichiometrically and oxidatively, in a non-specific manner without any external reductant added, under physiological conditions. Spectro-electrochemical investigations of PtL-Cl were carried out in comparison with the analogue CuL-Cl as a reference compound. The results support a phenolate oxidation, generating a phenoxyl radical responsible for the ligand-based DNA cleavage property of the title compounds. Time-dependent in vitro cytotoxicity assays were performed with both PtL-Cl and CuL-Cl in various cancer cell lines. The compound CuL-Cl overcomes cisplatin-resistance in ovarian carcinoma and mouse leukaemia cell lines, with additional activity in some other cells. The platinum analogue, PtL-Cl also inhibits cell-proliferation selectively. Additionally, cellular-uptake studies performed for both compounds in ovarian carcinoma cell lines showed that significant amounts of Pt and Cu were accumulated in the A2780 and A2780R cancer cells. The conformational and structural changes induced by PtL-Cl and CuL-Cl on calf thymus DNA and phi X174 supercoiled phage DNA at ambient conditions were followed by electrophoretic mobility assay and circular dichroism spectroscopy. The compounds induce extensive DNA degradation and unwinding, along with formation of a monoadduct at the DNA minor groove. Thus, hybrid effects of metal-centre variation, multiple DNA-binding modes and ligand-based redox activity towards cancer cell-growth inhibition have been demonstrated. Finally, reactions of PtL-Cl with DNA model bases (9-Ethylguanine and 5'-GMP) followed by NMR and MS showed slow binding at Guanine-N7 and for the double stranded self complimentary oligonucleotide d(GTCGAC)(2) in the minor groove
Efeito do Esteroíde nos Limiares Agudos de um Eletrodo Atrial e Ventricular de Fixaçao Ativa
Objetivo: Comparar a performace de um eletrodo bipolar permanente com fixaçao ativa e colar de esteróide, com outro eletrodo semelhante, mas sem o colar de esteróide. Material e Método: Este estudo foi realizado em 2 fases em 3 centros no Brasil: na fase atrial eletrodos Sweet Tip Rx e Sweet Tip foram implantados em 16 e 8 pacientes, respectivamente. Em todos os pacientes os limiares de voltagem (largura de pulso = 0,5 ms) e a largura de pulso (amplitude = 1,5V ) foram medidos por ocasiao da alta hospitalar, 2 semanas e 3 ou 4 meses após o implante. Resultados: Na avaliaçao de 2 semanas a média dos limiares de voltagem foi de 0,57± 0,04 V para o Sweet Tip Rx e 1,0 ± 0,19V para o Sweet Tip (p0,49) e, para os eletrodos ventriculares, 0,14 ± 0,02ms para o Sweet Tip Rx e 0,31 ± 0,05ms para o Sweet Tip (pConclusao: Os eletrodos envolvidos com esteróide tiveram um limiar significativamente menor após o implante
Efeito do Esteroíde nos Limiares Agudos de um Eletrodo Atrial e Ventricular de Fixaçao Ativa
Objetivo: Comparar a performace de um eletrodo bipolar permanente com fixaçao ativa e colar de esteróide, com outro eletrodo semelhante, mas sem o colar de esteróide. Material e Método: Este estudo foi realizado em 2 fases em 3 centros no Brasil: na fase atrial eletrodos Sweet Tip Rx e Sweet Tip foram implantados em 16 e 8 pacientes, respectivamente. Em todos os pacientes os limiares de voltagem (largura de pulso = 0,5 ms) e a largura de pulso (amplitude = 1,5V ) foram medidos por ocasiao da alta hospitalar, 2 semanas e 3 ou 4 meses após o implante. Resultados: Na avaliaçao de 2 semanas a média dos limiares de voltagem foi de 0,57± 0,04 V para o Sweet Tip Rx e 1,0 ± 0,19V para o Sweet Tip (p0,49) e, para os eletrodos ventriculares, 0,14 ± 0,02ms para o Sweet Tip Rx e 0,31 ± 0,05ms para o Sweet Tip (pConclusao: Os eletrodos envolvidos com esteróide tiveram um limiar significativamente menor após o implante
Local Prefrontal Cortex TMS-Induced Reactivity Is Related to Working Memory and Reasoning in Middle-Aged Adults
Introduction: The prefrontal cortex (PFC) plays a crucial role in cognition, particularly in executive functions. Cortical reactivity measured with Transcranial Magnetic Stimulation combined with Electroencephalography (TMS-EEG) is altered in pathological conditions, and it may also be a marker of cognitive status in middle-aged adults. In this study, we investigated the associations between cognitive measures and TMS evoked EEG reactivity and explored whether the effects of this relationship were related to neurofilament light chain levels (NfL), a marker of neuroaxonal damage. Methods: Fifty two healthy middle-aged adults (41–65 years) from the Barcelona Brain Health Initiative cohort underwent TMS-EEG, a comprehensive neuropsychological assessment, and a blood test for NfL levels. Global and Local Mean-Field Power (GMFP/LMFP), two measures of cortical reactivity, were quantified after left prefrontal cortex (L-PFC) stimulation, and cognition was set as the outcome of the regression analysis. The left inferior parietal lobe (L-IPL) was used as a control stimulation condition. Results: Local reactivity was significantly associated with working memory and reasoning only after L-PFC stimulation. No associations were found between NfL and cognition. These specific associations were independent of the status of neuroaxonal damage indexed by the NfL biomarker and remained after adjusting for age, biological sex, and education. Conclusion: Our results demonstrate that TMS evoked EEG reactivity at the L-PFC, but not the L-IPL, is related to the cognitive status of middle-aged individuals and independent of NfL levels, and may become a valuable biomarker of frontal lobe-associated cognitive function
Red wine consumption increases antioxidant status and decreases oxidative stress in the circulation of both young and old humans
Background: Red wine contains a naturally rich source of antioxidants, which may protect the body from oxidative stress, a determinant of age-related disease. The current study set out to determine the in vivo effects of moderate red wine consumption on antioxidant status and oxidative stress in the circulation.Methods: 20 young (18–30 yrs) and 20 older (≥ 50 yrs) volunteers were recruited. Each age group was randomly divided into treatment subjects who consumed 400 mL/day of red wine for two weeks, or control subjects who abstained from alcohol for two weeks, after which they crossed over into the other group. Blood samples were collected before and after red wine consumption and were used for analysis of whole blood glutathione (GSH), plasma malondialdehyde (MDA) and serum total antioxidant status.Results: Results from this study show consumption of red wine induced significant increases in plasma total antioxidant status (P < 0.03), and significant decreases in plasma MDA (P < 0.001) and GSH (P < 0.004) in young and old subjects. The results show that the consumption of 400 mL/day of red wine for two weeks, significantly increases antioxidant status and decreases oxidative stress in the circulation.Conclusion: It may be implied from this data that red wine provides general oxidative protection and to lipid systems in circulation via the increase in antioxidant status.<br /
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