Zero-field Kondo splitting and quantum-critical transition in double quantum dots

Double quantum dots offer unique possibilities for the study of many-body correlations. A system containing one Kondo dot and one effectively noninteracting dot maps onto a single-impurity Anderson model with a structured (nonconstant) density of states. Numerical renormalization-group calculations show that while band filtering through the resonant dot splits the Kondo resonance, the singlet ground state is robust. The system can also be continuously tuned to create a pseudogapped density of states and access a quantum critical point separating Kondo and non-Kondo phases.Comment: 4 pages, 4 figures; Accepted for publication in Physical Review Letter

p-Sulfonic acid calixarenes as efficient and reusable organocatalysts for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/-thiones

AbstractA new and efficient methodology is proposed for obtaining 3,4-dihydropyrimidin-2(1H)-ones/-thiones through Biginelli reactions. It is based on the use of less than the stoichiometric amount of p-sulfonic acid calixarenes as organocatalysts. A number of aromatic aldehydes as well as urea or thiourea can be employed for successfully synthesizing the corresponding Biginelli adducts. The described methodology is devoid of metal-containing catalysts, which in turn is very attractive for safely producing 3,4-dihydropyrimidin-2-(1H)-ones/-thiones of pharmacological interest. In addition, the catalyst efficiency is not compromised after its successive use in reactions. This is the first report about the application of calixarenes as catalysts in the multicomponent Biginelli reaction

Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment

Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucária, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin

Design, synthesis and the effect of 1,2,3-triazole sialylmimetic neoglycoconjugates on Trypanosoma cruzi and its cell surface trans-sialidase

This work describes the synthesis of a series of sialylmimetic neoglycoconjugates represented by 1,4-disubstituted 1,2,3-triazole-sialic acid derivatives containing galactose modified at either C-1 or C-6 positions, glucose or gulose at C-3 position, and by the amino acid derivative 1,2,3-triazole fused threonine-3-O-galactose as potential TcTS inhibitors and anti-trypanosomal agents. This series was obtained by Cu(I)-catalysed azide-alkyne cycloaddition reaction ('click chemistry') between the azido-functionalized sugars 1-N(3)-Gal (commercial), 6-N(3)-Gal, 3-N(3)-Glc and 3-N(3)-Gul with the corresponding alkyne-based 2-propynyl-sialic acid, as well as by click chemistry reaction between the amino acid N(3)-ThrOBn with 3-O-propynyl-GalOMe. the 1,2,3-triazole linked sialic acid-6-O-galactose and the sialic acid-galactopyranoside showed high Trypanosoma cruzi trans-sialidase (TcTS) inhibitory activity at 1.0 mM (approx. 90%), whilst only the former displayed relevant trypanocidal activity (IC(50) 260 mu M). These results highlight the 1,2,3-triazole linked sialic acid-6-O-galactose as a prototype for further design of new neoglycoconjugates against Chagas' disease. (C) 2011 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)USP, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP, BrazilUSP, Fac Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc

Impacts of the “Plastic Bag Law” in the Grocery Retail in the city of São Paulo/Brazil

Among the waste generated by retail, the plastic bag, which has its main use for the transportation of products, is a constant component of household waste and negatively impacts the environment. In this context, Municipal Law 15,374 prohibited the free distribution of plastic bags in the city of São Paulo / Brazil, as of April 2015, and brought as an alternative the use of returnable bags and biodegradable bags in an attempt to reduce environmental impact caused by improper disposal of the plastic. Therefore, the purpose of this research was to analyze the impact of said Law on the reduction of the purchase of plastic bags made by the grocery retail in the city of São Paulo. A survey was conducted with data from two grocery retail stores in the city of São Paulo, between January and December 2015. The results showed that the implementation of the law reduced the volume of plastic bags provided by supermarkets without compromising the flow of people and financial income

Influência da função pulmonar e da força muscular na capacidade funcional de portadores de doença pulmonar obstrutiva crónica = The influence of lung function and muscular strength on the functional capacity of chronic obstructive pulmonary disease patients

Objectivo : Determinar que variável entre o volume expirado forçado no primeiro segundo (VEF1), a pressão parcial do oxigénio no sangue arterial (PaO2), a hipoxemia nocturna e a força muscular do quadricípite femoral pode predizer a distância percorrida no teste de caminhada de seis minutos (TC6) em doentes com DPOC. Doentes e métodos : Um estudo observacional do tipo transversal, envolvendo trinta doentes encaminhados a um programa de reabilitação pulmonar de um hospital universitário. A função pulmonar foi avaliada por espirometria, gasometria arterial e oximetria nocturna. A função muscular pela força muscular do quadricípite femoral e a avaliação da capacidade funcional pelo TC6. Resultados : A análise de regressão bivariada mostrou que a força do quadricípite femoral foi a única variá- vel que se mostrou estatisticamente significativa (p = 0,002) em predizer a distância, sendo responsá- vel por 38% da variância do TC6. Para essas variáveis a relação estabelecida estatisticamente foi que para cada quilo de força do quadricípite femoral, os doentes caminharam 5,9 metros no TC6. Conclusão : Os resultados indicam a importância da força muscular do MI em testes de esforço submáximo. Entre as variáveis estudadas, apenas a força muscular do quadricípite femoral pôde predizer a distância percorrida no TC6 em portadores de doença pulmonar obstrutiva crónica. Aim : To determine which variable (forced expiratory volume in 1 second (FEV1), partial pressure of oxygen in arterial blood (PaO2), nocturnal hypoxaemia and muscular strength of femoral quadriceps) can predict the distance walked in the six-minute walk test (6MWT) by COPD patients. Methods : A cross-sectional and observational study of thirty patients referred to a pulmonary rehabilita tion programme at a university hospital. Lung function was evaluated by spirometry, arterial blood gas analysis and nocturnal oximetry. Muscle function was evaluated by quadriceps strength and functional capacity by the 6MWT. Results : Bivariate regression analysis showed that quadriceps strength, was the only variable to correlate significantly with the distance walked in the 6MWT (p=0.002), accounting for 38% of the 6MWT variance. The statistical relationship established for these variables was 1kg of quadriceps strength equalled 5.9 metres walked in the 6MWT. Conclusions : Our results showed the importance of lower limb muscle strength in submaximal exercise testing. We conclude that femoral quadriceps muscle strength is the only one of the variables studied which can predict the distance COPD patients walk in the 6MWT

Click chemistry oligomerisation of azido-alkyne-functionalised galactose accesses triazole-linked linear oligomers and macrocycles that inhibit Trypanosoma cruzi macrophage invasion

AbstractReaction of 2-(2-(2-azidoethoxy)ethoxy)ethyl 6-O-(prop-2-ynyl)-β-d-galactopyranoside (7) under CuAAC conditions gives rise to mixed cyclic and linear triazole-linked oligomers, with individual compounds up to d.p. 5 isolable, along with mixed larger oligomers. The linear compounds resolve en bloc from the cyclic materials by RP HPLC, but are separable by gel permeation chromatography. The triazole-linked oligomers—pseudo-galactooligomers—were demonstrated to be acceptor substrates for the multi-copy cell surface trans-sialidase of the human parasite Trypanosoma cruzi. In addition, these multivalent TcTS ligands were able to block macrophage invasion by T. cruzi

Vertical Distribution of Leaves and Stems on the Sward and Forage Intake by Lambs in Tifton-85 Pasture

Sward characteristics affect the performance of grazing livestock, especially for the youngest animals. The aim of this study was to evaluate the relationship between the vertical distribution of leaves and stems on the sward and the forage intake parameters of lambs in four sheep meat production systems grazing a Bermudagrass (Cynodon dactylon) cv. Tifton-85 pasture