Calcificação pulmonar metastática: relato de caso

Neste trabalho é relatado o caso de uma paciente do sexo feminino de 48 anos de idade, portadora de insuficiência renal crônica, em diálise há 13 anos, tendo iniciado o quadro com hemoptise, febre, tosse produtiva e dispneia aos grandes esforços. A radiografia de tórax apresentou opacidades mal definidas predominando nos terços médios e inferiores dos pulmões. A tomografia computadorizada de tórax evidenciou opacidades em vidro fosco associadas com nódulos centrolobulares mal definidos, com atenuação em vidro fosco. A paciente foi submetida a lavagem broncoalveolar, que foi negativa para micobactérias e fungos. Com base nesses achados, foi realizada biópsia pulmonar a céu aberto, que revelou calcificação pulmonar metastática.

Vidros recobertos com camadas delgadas transparentes de SnO2

SnO2 thin layers, prepared from aqueous colloidal suspensions by the sol-gel process, have been dip-coated on commercial borosilicate glasses. The effect of the conditions of deposition on the optical and structural characteristics of the thin layers was analysed by UV-Vis spectroscopy, x-ray reflectometry and electron scanning microscopy. Layers prepared with withdrawal speed in between 0.1 and 10cm/min show thickness smaller than 90nm, roughness of the order of 2nm and transmittance higher than 80%, resulting in good optical quality samples. The roughness increases from 2 to 11nm as the withdrawal speed increases from 10 to 80cm/min, what seems to be associated to the enlargement of the layers thickness (> 90nm). The measurements of mass loss, done after etching with fluoridric acid show that the coated samples are more corrosion resistant than the uncoated borosilicate glass.

Síntese e atividade antibacteriana de imidas cíclicas: 3,4-dicloromaleimidas e 3-cloro-4-substituída-maleimidas

In the present study, new N-aryl and N-alkylarylcyclic imides were synthesized and their antibacterial properties against Escherichia coli and Staphylococcus aureus were evaluated by using the diffusion method. All compounds were obtained in good yield (54 - 95%) and characterized by spectral data (¹H-NMR, MS, IR) and elemental analysis (CHN). The biological results indicated that some compounds exert significative antibacterial effects, confirming previous studies on biological activities of cyclic imides.

Contaminação por crômio de águas de rios proveniente de curtumes em Minas Gerais

In order to evaluate the chromium contamination from tannery discharges into rivers in the State of Minas Gerais, samples of water and suspended material were collected and submitted to chemical analysis. The total content of chromium in the samples was measured by flame atomic absorption spectrophotometry. Water samples were analysed by standard addition method, while chromium concentration in suspended materials was determined by calibration curves. Localities investigated were Ipatinga, Matias Barbosa, Dores de Campo, Ressaquinha, Ubá and Juiz de Fora. Samples from a not-industrialized area were also analysed to obtain regional background values. Metal inputs were related to effluent discharges into the rivers. Suspended material transported Cr downriver. Chromium concentration in river water exceeded 656 times the value of the Brazilian Environmental Standards, while its concentration in suspended material ranged from 15 to 11066 µg g-1.

Os 200 anos da pilha elétrica

In celebration of the 200th anniversary of the electric pile, invented by Alessandro Volta, a synopsis of his letter to The Royal Society (London) and of his biography is presented.

Dimensão fractal de ácidos húmicos em diferentes condições experimentais

The determination of fractal dimension (D) of humic particles was achieved by the turbidimetric technique where diluted suspensions of humic acids, in different experimental conditions, were analyzed by spectrophotometry UV-Vis. The slope of the lines (beta) was taken from the graphics (logtauvs loglambda) to obtain D. The results show that the values of D changed according to pH (3.0, 5.0 and 7.0), temperature (25 and 5 ºC) and shaking (magnetic and horizontal). In general, the value of D decreased with the increment of pH, increase of shaking and decrease of temperature.

Avaliação da susceptibilidade magnética usando uma balança analítica

A simple system to measure the magnetic susceptibility of different materials is presented. The system uses an analytical scale with sensitivity on the order of micrograms and a permanent NdBFe magnet, based in the Rankine method. In this apparatus, the sample is placed near to the magnet that is fixed on the scale. Depending on the magnetic properties of the sample, an attractive or repulsive force will appear between the magnet and the magnetizing sample. Measuring this force, registered by the scale as a mass, the magnetic parameters such as: permeability and susceptibility of the sample can be determined. Despite it is simplicity the method is quantitative, precise and easily reproducible in many laboratories, what makes it attractive for teaching experiments.

A primeira lei da termodinâmica dos processos homogêneos

Thermodynamics of homogeneous processes, which corresponds to the very special situation in thermodynamics of continuous media, is used to discuss the first law. An important part of this work is the exposition of some typical mathematical errors, frequently found in the traditional presentation of thermodynamics. The concepts of state and process functions are discussed, as well as reverse and reversible processes, temporality and its implications on thermodynamics, energy reservoirs and symmetry. Our proposal is to present the first law by using a time dependent viewpoint coherent with mechanics and the foundations of that viewpoint.

Distribuição e biodisponibilidade de crômio em solos contaminados por resíduos de couro

Samples of soil, water and sediment were collected and analyzed in order to evaluate chromium contamination due to deposition of tannery residues onto soils under different management regimes. The results showed that soils used for sugar cane cultivation were not adversely impacted. However, in the case of mango plantations, variable concentrations of chromium were measured in the soil profile, with 22.2% of values being higher than permitted legal limits, and 38.9% being at levels requiring remediation. Concentrations of bioavailable chromium were lower than the detection limit of the method (0.01 mg of chromium kg-1 of soil), indicating that all of the chromium present in the samples was either complexed or in an insoluble form. Chromium concentrations measured in samples of water and sediments were indicative of low mobility of the metal in soils. The main cause of differences found between soil samples obtained from different cultivations was the type of soil management.

A quantidade de matéria nas ciências clássicas

The chemical amount values vary in a discrete or continuous form, depending on the approach used to describe the system. In classical sciences, the chemical amount is a property of the macroscopic system and, like any other property of the system, it varies continuously. This is neither inconsistent with the concept of indivisible particles forming the system, nor a mere approximation, but it is a sound concept which enables the use of differential calculus, for instance, in chemical thermodynamics. It is shown that the fundamental laws of chemistry are absolutely compatible to the continuous concept of the chemical amount.

An expeditious and consistent procedure for tetrahydrofuran (THF) drying and deoxygenation by the still apparatus

Despite the availability of alternative methods for drying tetrahydrofuran (THF), the use of the still apparatus, wherein a THF solution containing Na-bezophenone ketyl is heated to reflux, remains widespread. We herein propose a set of procedures to solve the problems usually faced in applying this drying technique. Moreover, a discussion is made on the chemical knowledge underlying such procedures. Safety and economy issues concerned with the operation of the THF still apparatus are also discussed.

HIV: mecanismo de replicação, alvos farmacológicos e inibição por produtos derivados de plantas

The AIDS epidemy has spread out and led to the diversification on the research for new antiviral drugs. Natural products, especially those derived from plants, are well-recognized as excellent sources of new drugs. Several of them have inhibitory activity against HIV replication, and some have been already clinically tested, with favorable results. This review presents the biochemical basis of the viral cycle and the research up to date on the identification, determination of the mechanism of biological action together with the therapeutical potential of plants-derived natural products, in the inhibition of HIV.