Formation of oriented nickel aggregates in rutile single crystals by Ni implantation

The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5 x 10(17) cm(-2) and 2.0 x 10(17) cm(-2) with 150 keV energy, corresponding to maximum atomic concentrations between 9 at% and 27 at% at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibit superparamagnetic behavior for the two higher fluences, which is attributed to the formation of nanosized nickel clusters with an average size related with the implanted concentration, while only paramagnetic behavior is observed for the lowest fluence. Annealing at 1073 K induces the aggregation of the implanted nickel and enhances the magnetization in all samples. The associated anisotropic behavior indicates preferred orientations of the nickel aggregates in the rutile lattice consistent with Rutherford backscattering spectrometry-channelling results. Electrical conductivity displays anisotropic behavior but no magnetoresistive effects were detected. (C) 2013 Elsevier B.V. All rights reserved.

Haptoglobin, acid phosphatase and demographic factors: obesity risk

The aim of this work is to study the risk of obesity posed by two genetic factors: haptoglobin phenotype and acid phosphatase phenotype, one enzymatic activity: acid phosphatase activity (ACP1), age and gender. Haptoglobin (Hp) is a protein of the immune system, and three phenotypes of Hp are found in humans: Hp1-1, Hp2-1, and Hp2-2. This protein is associated with a susceptibility to common pathological conditions, such as obesity. ACP1 is an intracellular enzyme The phenotypes of ACP1 (AA, AB, AC, BB, BC, CC) are also considered. We took a sample of 127 subjects with complete data from 714 registers. Since we intend to identify risk factors for obesity, an ordinal regression model is adjusted, using the Body Mass Index, BMI, to define weight categories. Haptoglobin phenotype, enzymatic activity of ACP1, acid phosphatase phenotype, age and gender are considered as regressor variables. We found three factors associated with an increased risk of obesity: phenotype Hp2-1 of haptoglobin (estimated odds ratio OR 11.54), phenotype AA of acid phosphatase (OR 33.788) and age (OR 1.39). The interaction between phenotype Hp2-1 and phenotype AC is associated with a decreased risk of obesity (OR 0.032); The interaction between phenotype AA and ACP1 activity is associated with a decreased risk of obesity (OR 0.954).

Comparação da fixação em formalina e em fixador molecular e sua influência em técnicas histoquímicas em tecido hepático

A Formalina 10% Tamponada (FNT 10%) é considerada o fixador de eleição nos Laboratórios de Anatomia Patológica. Contudo, a exposição a esta substância acarreta riscos para a saúde dos técnicos. A International Agency for Research on Cancer (IARC) classificou-a como cancerígeno humano e estudos relevam uma correlação positiva entre a exposição a formaldeído e o desenvolvimento de leucemia e leucemia mielóide. Torna-se relevante alterar o processo de fixação substituindo a FNT 10% por outros fixadores melhorando estas questões. Como tal, desenvolveram-se fixadores à base de outros compostos químicos que não formaldeído, como o Fixador Molecular Universal (UMFIX) que tem como base metanol e polietilenoglicol e que é usualmente utilizado com um processador rápido de micro-ondas. Pretende-se comparar as diferenças entre a fixação por FNT 10% e a fixação por UMFIX, em tecido hepático processado em processador rápido de micro-ondas, para as colorações de Hematoxilina-Eosina (H&E), Tricrómio de Gomori, Reticulina e PAS, através da qualidade final das lâminas testadas. A coloração de H&E foi a única que apresentou diferenças estatisticamente significativas entre os dois fixadores (p=0,032; α<0,05; Mann-Whitney). O UMFIX apresenta-se como um substituto da FNT 10% para o processamento rápido em micro-ondas, pois além de apresentar lâminas com uma qualidade final semelhante ou superior às da FNT 10%, ultrapassa os riscos referidos.

Synthesis of Sub-5 NM Co-Doped SnO2 nanoparticles and their structural microstructural, optical and photocatalytic properties

A swift chemical route to synthesize Co-doped SnO2 nanopowders is described. Pure and highly stable Sn1-xCoxO2-delta (0 <= x <= 0.15) crystalline nanoparticles were synthesized, with mean grain sizes <5 nm and the dopant element homogeneously distributed in the SnO2 matrix. The UV-visible diffuse reflectance spectra of the Sn1-xCoxO2-delta samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The samples' Urbach energies were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn1-xCoxO2-delta samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn0.95Co0.05O2-delta nanoparticles in 60 min of irradiation. (C) 2014 Elsevier B.V. All rights reserved.