Barrier-free substitutional doping of graphene sheets with boron atoms: Ab initio calculations

Using ab initio methods, we propose a simple and effective way to substitutionally dope graphene sheets with boron. The method consists of selectively exposing each side of the graphene sheet to different elements. We first expose one side of the membrane to boron while the other side is exposed to nitrogen. Proceeding this way, the B atoms will be spontaneously incorporated into the graphene membrane without any activation barrier. In a second step, the system should be exposed to a H-rich environment, which will remove the CN radical from the layer and form HCN, leading to a perfect substitutional doping.

Influence of laser surface texturing on surface microstructure and mechanical properties of adhesive joined steel sheets

This work discusses the resultant microstructure of laser surface treated galvanised steel and the mechanical properties of adhesively bonded surfaces therein. The surface microstructure obtained at laser intensities between 170 and 1700 MW cm 22 exhibit zinc melting and cavity formation. The wavy surface morphology of the treated surface exhibits an average roughness Ra between 1.0 and 1.5 mu m, and a mean roughness depth R(z) of 8.6 mu m. Atomic force microscopic analyses revealed that the R(z) inside the laser shot cavities increased from 68 to 243 nm when the incident laser intensity was increased from 170 to 1700 MW cm(-2). X-ray fluorescence analyses were used to measure Zn coating thicknesses as a function of process parameters. Both X-ray fluorescence and X-ray diffraction analyses demonstrated that the protective coating remains at the material surface, and the steel structure beneath was not affected by the laser treatment. Tensile tests under peel strength conditions demonstrated that the laser treated adhesively joined samples had resistance strength up to 88 MPa, compared to a maximum of only 23 MPa for the untreated surfaces. The maximum deformation for rupture was also greatly increased from 0.07%, for the original surface, to 0.90% for the laser treated surfaces.

Long-term aging of fiber-cement corrugated sheets - The effect of carbonation, leaching and acid rain

This paper studies the performance of fiber-cement corrugated sheets exposed to long-term weathering, exploring the effect of different environments on fiber-cement degradation. Fiber-cement corrugated sheets that had been exposed to weathering, and in place for more than 30-years, were collected from two different Brazilian cities (Sao Paulo and Criciuma). Mechanical properties (MOR, MOE and fracture toughness) were tested on samples removed from the corrugated sheets. Microstructure was evaluated by X-ray diffraction, SEM with EDS analysis, MIP and TG. The results show that the 37-year-old asbestos-cement corrugated sheets from Sao Paulo presented similar characteristics to those of the non-aged asbestos-cement readily available on the market place. Conversely, deterioration of the asbestos-cement from the industrial area of Criciuma is related to acidic attack, along with carbonation and leaching as a consequence of continued exposition to acid rain during several decades. This process resulted in higher porosity and lower mechanical strength, revealing that leaching mechanisms can have important effect on the performance of thin fiber-cement sheets. (c) 2007 Elsevier Ltd. All rights reserved.

Loops, Chains, Sheets, and Networks from Variable Coordination of Cu(hfac)(2) with a Flexibly Hinged Aminoxyl Radical Ligand

One pair of reactants, Cu(hfac)(2) = M and the hinge-flexible radical ligand 5-(3-N-tert-butyl-N-aminoxylphenyl)pyrimidine (3PPN = L), yields a diverse set of five coordination complexes: a cyclic loop M(2)L(1) dimer; a 1:1 cocrystal between an M(2)L(2) loop and an ML(2) fragment; a ID chain of M(2)L(2) loops linked by M; two 2D M(3)L(2) networks of (M-L)(n) chains crosslinked by M with different repeat length pitches; a 3D M(3)L(2) network of M(2)L(2) loops cross-linking (M-L)(n)-type chains with connectivity different from those in the 2D networks. Most of the higher dimensional complexes exhibit reversible, temperature-dependent spin-state conversion of high-temperature paramagnetic states to lower magnetic moment states having antiferromagnetic exchange within Cu-ON bonds upon cooling, with accompanying bond contraction. The 3D complex also exhibited antiferromagnetic exchange between Cu(II) ions linked in chains through pyrimidine rings.

Absolute normalization for uncorrelated background with the event mixing technique

We present a method to determine the magnitude of the uncorrelated background distribution obtained with the event mixing technique, through the simultaneous observation of the projectile elastic scattering in different detectors, which correspond to random coincidences. The procedure is tested with alpha-d angular correlation data from the (6)Li + (59)Co reaction at E(lab) = 29.6 MeV. We also show that the method can be applied using the product of singles events, when singles measurements are available. (C) 2009 Elsevier B.V. All rights reserved.

An imaginary potential with universal normalization for dissipative processes in heavy-ion reactions

In this work we present new coupled channel calculations with the Sao Paulo potential (SPP) as the bare interaction, and an imaginary potential with system and energy independent normalization that has been developed to take into account dissipative processes in heavy-ion reactions. This imaginary potential is based on high-energy nucleon interaction in nuclear medium. Our theoretical predictions for energies up to approximate to 100 MeV/nucleon agree very well with the experimental data for the p, n + nucleus, (16)O + (27)Al, (16)O + (60)Ni, (58)Ni + (124)Sn, and weakly bound projectile (7)Li + (120)Sn systems. (C) 2008 Elsevier B.V. All rights reserved.

Normalization procedure for relaxation studies in NMR quantum information processing

NMR quantum information processing studies rely on the reconstruction of the density matrix representing the so-called pseudo-pure states (PPS). An initially pure part of a PPS state undergoes unitary and non-unitary (relaxation) transformations during a computation process, causing a ""loss of purity"" until the equilibrium is reached. Besides, upon relaxation, the nuclear polarization varies in time, a fact which must be taken into account when comparing density matrices at different instants. Attempting to use time-fixed normalization procedures when relaxation is present, leads to various anomalies on matrices populations. On this paper we propose a method which takes into account the time-dependence of the normalization factor. From a generic form for the deviation density matrix an expression for the relaxing initial pure state is deduced. The method is exemplified with an experiment of relaxation of the concurrence of a pseudo-entangled state, which exhibits the phenomenon of sudden death, and the relaxation of the Wigner function of a pseudo-cat state.

Electromyographic activity of masticatory muscles in women with osteoporosis

The purpose of this study was to analyze the electromyographic (EMG) activity and the maximal molar bite force in women diagnosed with osteoporosis in the maxillary and mandibular regions, considering the habits and conditions that lead to development of generalized skeletal bone loss, including on face bones, can disturb the functional harmony of the stomatognathic system. Twenty-seven women with mandibular and maxillary osteoporosis and 27 healthy controls volunteered to participate in the study. A 5-channel electromyographer was used. Muscle activity was evaluated by means of EMG recordings of the masticatory musculature (masseter and temporalis muscles, bilaterally) during the following clinical conditions: rest (5 s); right and left lateral excursions (5 s); protrusion (5 s); maximal dental clenching on Parafilm™ (4 s) and maximal voluntary contraction (4 s). This latter clinical condition was used as the normalization factor of the sample data. It was observed that individuals with osteoporosis presented greater EMG activity when maintaining mandible posture conditions and less activity during dental clenching and when obtaining maximal molar bite force. It may be concluded that facial osteoporosis can interfere on the patterns of masticatory muscle activation and maximal bite force of the stomatognathic system.

Thermal performance of sisal fiber-cement roofing tiles for rural constructions

Roofing provides the main protection against direct solar radiation in animal housing. Appropriate thermal properties of roofing materials tend to improve the thermal comfort in the inner ambient. Nonasbestos fiber-cement roofing components reinforced with cellulose pulp from sisal (Agave sisalana) were produced by slurry and dewatering techniques, with an optional addition of polypropylene fibers. Nonasbestos tiles were evaluated and compared with commercially available asbestos-cement sheets and ceramic tiles (frequently chosen as roofing materials for animal housing). Thermal conductivity and thermal diffusivity of tiles were determined by the parallel hot-wire method, along with the evaluation of the downside surface temperature. Cement-based components reinforced with sisal pulp presented better thermal performance at room temperature (25ºC), while those reinforced with sisal pulp added by polypropylene fibers presented better thermal performance at 60ºC. Non-asbestos cement tiles provided more efficient protection against radiation than asbestos corrugated sheets.

Doença granulomatosa crônica: diagnóstico no primeiro episódio infeccioso

OBJETIVO: Relatar caso ilustrativo de doença granulomatosa crônica cujo diagnóstico ocorreu durante o aparecimento do primeiro episódio infeccioso, colaborando com a iniciativa do Brazilian Group for Immunodeficiency para a sensibilização do pediatra geral em relação ao diagnóstico precoce das imunodeficiências primárias, o que está associado a melhor qualidade de vida e maior sobrevida desses indivíduos. DESCRIÇÃO DE CASO: Paciente do sexo masculino, 39 dias de vida, admitido em pronto-socorro pediátrico por febre alta há cinco dias e irritabilidade. No dia seguinte, observou-se abscesso cervical, isolando-se Staphylococcus aureus comunitário. Durante a internação, ocorreram outros abscessos superficiais e em cadeias ganglionares profundas, além de resposta lenta aos antimicrobianos. Solicitou-se investigação para imunodeficiências, que confirmou a hipótese de doença granulomatosa crônica por quantificação dos ânions superóxido e teste de redução do nitrobluetetrazolio. Paciente foi encaminhado a serviço especializado, no qual identificou-se doador de medula óssea compatível, realizando-se o transplante seis meses após o diagnóstico. Quatro meses após o transplante, ocorreu normalização do burst oxidativo, indicando sucesso. COMENTÁRIOS: O paciente mostrou apresentação típica da doença, o que permitiu seu diagnóstico por pediatras gerais já na primeira infecção, tendo como consequência o acompanhamento por especialistas em imunodeficiências primárias, a introdução da profilaxia antimicrobiana e a procura bem sucedida de doador de medula HLA-compatível.

High resolution study of 104Pd(d,t)103Pd

Information collected in the present high resolution study of 104Pd(d,t)103Pd is interpreted within the systematics of the A ~ 100 region. The paper complements data previously presented by the S.Paulo Group, which were taken with the Pelletron-Enge-Spectrograph facility. A one-to-one correspondence to gamma ray results for 103Pd, collected by the Nuclear Data Sheets (NDS), was achieved and at least four open questions were settled. More reliable spectroscopic strengths were extracted in the present study.

Avaliação da contaminação por elementos metálicos dos sedimentos do Estuário Santos - São Vicente

Three approaches were applied to evaluate metal contamination in 41 sediment samples from the Santos - São Vicente Estuarine System: normalization to Al, statistical analysis and sediment quality guidelines (SQGs). The results showed increases in the concentrations of Zn, Ni, Pb, Cd, Cr and Hg, which seemed to be associated with human activities. The levels of Al, Fe and Co probably were associated with crustal material or natural weathering processes. About 45% of the samples presented concentrations exceeding TEL-ERL, levels occasionally associated with adverse biological effects. Four of these samples presented concentrations above PEL-ERM, levels frequently associated with adverse biological effects.

Discrepancies among ecological, household, and individual data on fruits and vegetables consumption in Brazil

Information on fruits and vegetables consumption in Brazil in the three levels of dietary data was analyzed and compared. Data about national supply came from Food Balance Sheets compiled by the FAO; household availability information was obtained from the Brazilian National Household Budget Survey (HBS); and actual intake information came from a large individual dietary intake survey that was representative of the adult population of São Paulo city. All sources of information were collected between 2002 and 2003. A subset of the HBS, representative of São Paulo city, was used in our analysis in order to improve the quality of the comparison with actual intake data. The ratio of national supply to household availability of fruits and vegetables was 2.6 while the ratio of national supply to actual intake was 4.0. The discrepancy ratio in the comparison between household availability and actual intake was smaller, 1.6. While the use of supply and availability data has advantages, as lower cost, must be taken into account that these sources tend to overestimate actual intake of fruits and vegetables.

Validation of reference genes for gene expression studies in the honey bee, Apis mellifera, by quantitative real-time RT-PCR

For obtaining accurate and reliable gene expression results it is essential that quantitative real-time RT-PCR (qRT-PCR) data are normalized with appropriate reference genes. The current exponential increase in postgenomic studies on the honey bee, Apis mellifera, makes the standardization of qRT-PCR results an important task for ongoing community efforts. For this aim we selected four candidate reference genes (actin, ribosomal protein 49, elongation factor 1-alpha, tbp-association factor) and used three software-based approaches (geNorm, BestKeeper and NormFinder) to evaluate the suitability of these genes as endogenous controls. Their expression was examined during honey bee development, in different tissues, and after juvenile hormone exposure. Furthermore, the importance of choosing an appropriate reference gene was investigated for two developmentally regulated target genes. The results led us to consider all four candidate genes as suitable genes for normalization in A. mellifera. However, each condition evaluated in this study revealed a specific set of genes as the most appropriated ones.

Selection of suitable housekeeping genes for expression analysis in glioblastoma using quantitative RT-PCR

Background: Considering the broad variation in the expression of housekeeping genes among tissues and experimental situations, studies using quantitative RT-PCR require strict definition of adequate endogenous controls. For glioblastoma, the most common type of tumor in the central nervous system, there was no previous report regarding this issue. Results: Here we show that amongst seven frequently used housekeeping genes TBP and HPRT1 are adequate references for glioblastoma gene expression analysis. Evaluation of the expression levels of 12 target genes utilizing different endogenous controls revealed that the normalization method applied might introduce errors in the estimation of relative quantities. Genes presenting expression levels which do not significantly differ between tumor and normal tissues can be considered either increased or decreased if unsuitable reference genes are applied. Most importantly, genes showing significant differences in expression levels between tumor and normal tissues can be missed. We also demonstrated that the Holliday Junction Recognizing Protein, a novel DNA repair protein over expressed in lung cancer, is extremely over-expressed in glioblastoma, with a median change of about 134 fold. Conclusion: Altogether, our data show the relevance of previous validation of candidate control genes for each experimental model and indicate TBP plus HPRT1 as suitable references for studies on glioblastoma gene expression.