Transmission of wireless neural signals through a 0.18 µm CMOS low-power amplifier.

In the field of Brain Machine Interfaces (BMI) researchers still are not able to produce clinically viable solutions that meet the requirements of long-term operation without the use of wires or batteries. Another problem is neural compatibility with the electrode probes. One of the possible ways of approaching these problems is the use of semiconductor biocompatible materials (silicon carbide) combined with an integrated circuit designed to operate with low power consumption. This paper describes a low-power neural signal amplifier chip, named Cortex, fabricated using 0.18 µm CMOS process technology with all electronics integrated in an area of 0.40 mm(2). The chip has 4 channels, total power consumption of only 144 µW, and is impedance matched to silicon carbide biocompatible electrodes.

Infecção toxoplásmica causa hipertrofia da parede do cólon de frangos / Toxoplasmic infecction causes hipertrophy of the chicken colon wall

Estudaram-se os efeitos da infecção toxoplásmica sobre a morfometria da parede intestinal, a distribuição de fibras colágenas e a dinâmica de mucinas secretadas no cólon de frangos. Foram utilizados 16 frangos machos de linhagem comercial, com 26 dias de idade. As aves foram distribuídas, aleatoriamente, em três grupos (G). As do G1 não receberam inóculo e se caracterizaram como grupo-controle; nas do G2, foram inoculados cistos teciduais da cepa ME49 de Toxoplasma gondii; e nos G3, oocistos da cepa M7741 de T. gondii. Após 60 dias da inoculação, os animais foram sacrificados para coleta do cólon, o qual foi submetido à rotina de processamento histológico. Em G2 e G3, observou-se hipertrofia da parede do cólon, contudo não houve alteração na proporção do número de células caliciformes e de enterócitos presentes no epitélio intestinal.

The effects of toxoplasmosis on the intestinal wall morphometry, the distribution of collagen fibers, and the dynamic of mucins secreted in the chicken colon were analyzed. Sixteen 26-day-old male Cobb chicks (Gallus gallus) were randomly distributed into three groups (G1, G2, and G3). G1 received no inoculums and characterized the control group, G2 was inoculated with tissue cysts of ME49 strain of Toxoplasma gondii, and G3 was inoculated with oocytes of M7741 strain of T. gondii. After 60 days of inoculation, the animals were slaughtered and had their colon collected and submitted to histological processing. Transversal cuts (4μm) were stained with Hematoxylin-Eosin (HE), Periodic Acid Schiff (PAS), Alcian Blue pH 2.5, Alcian Blue (AB) pH 1.0, and Azan. G2 and G3 animals showed hypertrophy of the colon wall, but the proportion between the number of goblet cells and enterocytes present in the intestinal epithelium was not altered.

Matrix isolation FTIR spectroscopic and theoretical study of 3,3-dichloro-1,1,1-trifluoropropane (HCFC-243).

The molecular structure and infrared spectrum of the atmospheric pollutant 3,3-dichloro-1,1,1-trifluoropropane (HCFC-243) were characterized experimentally and theoretically. The theoretical calculations show the existence of two conformers, with the gauche (G) and trans (T) orientation around the HCCC dihedral angle. Conformer G was calculated to be more stable than form T by more than 10 kJ mol (-1). In consonance with the large predicted relative energy of conformer T, only the G form was identified spectroscopically in cryogenic argon (10 K) and xenon (20 K) matrices prepared from room-temperature equilibrium vapor of the compound. The observed infrared spectra of the matrix-isolated HCFC-243 were interpreted with the aid of high-level density functional theory calculations and normal coordinate analysis. For experimental identification of the weakest IR absorption bands, the spectrum of HCFC-243 in the neat solid state at 145 K was obtained. This spectrum also confirmed the sole presence of the G conformer in the sample. Natural bond orbital and atomic charge analyses were carried out for the two conformers to shed light on the most important intramolecular interactions in the two conformers, in particular those responsible for their relative stability.

A theoretical prediction of stability in hydrogen-bonded complexes formed between oxirane and oxetane rings with HX (X=F and Cl).

The optimised geometries of heterocyclic hydrogen-bonded complexes, C2H4O...HX and C3H6O...HX, where X=F or Cl, were determined at DFT/B3LYP/6-311++G(d,p) computational level. Structural, electronic and vibrational properties of these complexes are used in order to compare the strained ring, which confer the great reactivity of these heterocyclic rings with monoprotic acids, forming a primary hydrogen bond. A secondary hydrogen bond between the hydrogen atoms of the CH2 groups and the halide species also takes place, thus causing a nonlinearity (characterized by the theta angle), in the primary hydrogen bond.

Aerosols concentration in the Candiota area applying different gravimetric methods of sampling and numeric modelling.

The main purpose of the present work is to study the concentration of atmospheric particles in the Candiota region, in the state of Rio Grande do Sul, where the Presidente Médici coal power plant is located. Aerosol samples were collected at the studied locations between December 2000 and December 2001 during 24 h periods at 15 day intervals using HV PM10 and dichotomous samplers. Then, the values obtained with the ISCST (Industrial Source Complex Term) model, with the HV PM10 sampler at all studied stations, and with the dichotomous sampler at the 8 de Agosto station were compared with each other. The results show that the values for the model had been underestimated in relation to the HV PM10 data for the studied stations, but agreed with the values obtained with the dichotomous sampler.