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The present investigation was designed to distinguish prostate cancer and benign prostate hyperplasia by lectin-prostate specific antigen (PSA) binding.The quantitative precipitin method of concanavalin A (Con A)-carbohydrate interaction was explored with the serum PSA of patients suffering from prostatic complications.The carbohydrate content in the precipitate after binding of Con A with serum PSA of prostate cancer was significantly lower than that of benign prostate hyperplasia. This may be due to altered sugar chain structure or less glycosylation of PSA in prostate cancer.We conclude that a serum value3.0 microg/ml of the carbohydrate content of Con A-PSA precipitate indicates strong suspicion for prostate cancer and this cut off level is effective in reducing the rate of unnecessary biopsies in men with total PSA value between 4.0 to 10.0 ng/ml.

We have investigated hypothalamic-pituitary-thyroid function in four groups of healthy elderly male humans. Group A (n=18, age range 20-45 years) served as healthy younger controls, group B (n=10, age range 50-60 years), group C (n=15, age range 60-70 years) and group D (n=16, age range 70-85 years) are the subjects of this study. Groups C and D showed significantly lower T3 and thyroid-stimulating hormone (TSH), and higher T4 levels with respect to controls. Evidence for TSH circadian modulation was found in group A (control) and group B subjects. The TRH-stimulated TSH peak was reduced among all elderly subjects with respect to controls and appeared to be pronounced with the ageing process. The maximal prolactin response was also inhibited with increasing age. Our study suggest that a resetting of the pituitary threshold for the TSH feed-back suppression along with complex alterations in peripheral thyroid hormone concentrations may, in turn, develop in older people and that appeared to manifest prominently among the oldest population. Additionally, the TSH nocturnal response appeared to be impaired with increasing age indicating an alteration of hypothalamic function.

A systematic study of the changes in photovoltaic properties of amorphous silicon p-i-n-type solar cells upon 100 h of white light (air mass (AM) 1.5 G) soaking has been made with the thickness of the i layer as variable parameter. The thickness of the i layer ranged from 700 to 7500 A. A significant rise in open-circuit voltage was observed in cells having an i layer less than 2500 A thick. This is explained as an effect of doping enhancement in the p and n layers of the cell upon light soaking. A study of collection efficiency spectra revealed that with an increase in i layer thickness the degradation increases towards longer wavelengths.

The results of optical absorption, IR absorption, Raman scattering and conductivity measurements for hydrogenated amorphous SiN films (a-Si1−xNx:H) prepared by r.f. magnetron sputtering have been presented. The variation in the nitrogen flow rate reveals three distinct regions: region A, a-Si1−xNx:H, where a kind of doping effect is shown in the conductivity, possibly due to the presence of fourfold-coordinated nitrogen atoms together with threefold-coordinated nitrogen atoms; region B, a-Si1−xNx:H with mainly threefold-coordinated nitrogen atoms; region C, Si3N4, with an optical gap near that of the stoichiometric compound. Effects of variation in hydrogen flow rate and substrate temperature have been studied for films in region B. A detailed investigation of light-induced changes for a-Si1−xNx:H films deposited with different nitrogen and hydrogen flow rates has been carried out. The results obtained indicate that films with a larger nitrogen content are more vulnerable to light-induced degradation.

The structural effect of high-dose implantation of nitrogen (N 2 + ) ions into iron, aluminium and nickel thin films has been investigated by high-voltage transmission electron microscopy (HVTEM) and selected area diffraction (SAD). It has been demonstrated that N 2 + acts as a glass former in these cases in the dose range between 8 × 10 17 and 1 × 10 18 N 2 + ions cm −2 . The metastability of the films so produced is discussed in the light of their annealing behaviour.

The electronic and optical properties of p-type a-Si:H films prepared by the rf glow discharge decomposition of a mixture of silane and diborane gases have been studied. The films have been prepared under different conditions which include variation of volume ration of B 2 H 6 and SiH 4 and rf power. The properties of compensated a-Si:H films prepared with very small boron doping have also been studied. The effects of mixing Ar with SiH 4 + B 2 H 6 mixture have been investigated. The properties actually studied include (1) dark conductivity, (2) steady state photoconductivity, (3) spectral response, (4) optical absorption and band gap. Attempts have been made to analyse the data to yield information about the transport mechanism, and the existence of hole and electron traps.

Light-induced changes in the electrical properties of magnetron-sputtered hydrogenated amorphous silicon films prepared at different deposition conditions have been investigated using light soaking at different temperatures. It has been observed that the direction of metastable change in the dark conductivity and activation energy is reserved as the light soaking temperature is increased although the change in the photoconductivity is maintained in the same direction throughout the temperature range studied.

Polycrystalline thin films of iron, nickel and aluminium were bombarded with N2+ ions with energies from 15 to 50 keV up to doses ranging from 1 × 1016 to 1.2 × 1018 ions cm−2 at room temperature. The implantation resulted in the formation of nitrides of both iron and nickel, as indicated by high voltage transmission electron microscopy and selected area diffraction patterns. No AlN phase could, however, be detected up to the implantation energy of 50 keV and dose of 1.2 × 1018 ions cm−2. The minimum energy and dose required for inducing compound formation in iron and nickel as well as the stability of the nitride phase have been investigated.

Tin doped indium oxide (ITO) films have been prepared by electron beam evaporation of hot pressed powder of 90% In 2 O 3 10% SnO 2 by weight. The parameters varied for optimization of film properties have been the substrate temperature and the partial pressure of the oxygen added. Properties which have been studied for characterization are the resistivity, Hall effect, transmittance and optical band gap. The structural studies have been made by X-ray diffraction and transmission electron microscopy. D.c. resistivity in the range 10 −3 −10 −4 Ω cm and visible transmittance in excess of 90% have been obtained for the films, with proper parametric adjustments. A 〈111〉 texture has been generally exhibited by the ITO films, using X-ray diffraction. This has been corroborated by electron diffraction studies.

The properties of undoped and p-type hydrogenated amorphous silicon carbide (a Si C:H) films were studied. Thea Si C:H films were prepared under different deposition conditions by the r.f. glow discharge decomposition of gas mixtures of silane and methane in an inductively coupled system. The p-typea Si C:H films were prepared from mixtures of silane, methane and diborane gases. The dark conductivity, photoconductivity, optical absorption, band gap and spectral response of these films were studied. By analysing the dark and photoconductivity data, information about the transport mechanism and the recombination processes in these films was obtained. It is suggested that there is possibly a significant change in the structure ofa Si C:H films with an increase in the carbon concentration that influences various properties of the material.

The influence of various deposition parameters on the properties of amorphous silicon (a-Si) thin films produced by r.f. magnetron sputtering was studied. The following parameters were varied: the incident r.f. power, the argon pressure in the sputtering chamber and the substrate temperature. The films were characterized by studying the dark conductivity and optical absorption from which the values of the band gaps were obtained. The most interesting result was that a-Si films prepared at high argon pressures showed significant photoconductivity. The results show that the magnetron sputtering method has good potential for producing high quality a-Si films.

Hydrogenated amorphous silicon-germanium films of different optical band gaps have been prepared by rf glow discharge method and their opto-electronic properties have been investigated. Photovoltaic quality of the material has been estimated in terms of a conceptually new Quality Factor, Q = photoconductivity X photosensitivity. At a deposition temperature of 250°C, films of Eg = 1.53 eV with O=5.6×101 have been reported.