Multiplication noise in multi-heterostructure avalanche photodiodes

Using a multi-feedback network representation, multiplication noise in two-stage and three-stage heterostructure avalanche photodiodes has been calculated for different degrees of carrier feedback over heterobarriers. Results show appreciable dependence of noise on carrier feedback in III–V compound APD's, the effect being less with larger number of stages.     

Lactic acid in human aqueous humour

IQs of rapists were compared to IQs of nonrapist prisoners convicted of violent crimes and nonrapist prisoners convicted of nonviolent crimes. Subjects were 136 male convicted felons in the Kentucky State Penitentiary. Determination of violent vs. nonviolent crimes other than rape was made upon consultation with a Kentucky Commonwealth Attorney. The results revealed significantly lower IQs for rapists compared to nonrapists convicted of violent crimes and compared to heterogeneous nonrapist convicts. The present research supports the findings of Karacan and co-workers, indicating a general tendency for rapists to have lower IQs than other convicted prisoners.     

Noncompressive myelopathy after lienorenal shunt in a patient with noncirrhotic portal fibrosis

Noncirrhotic portal fibrosis is a common cause of portal hypertension in India. We report the development of noncompressive myelopathy after a lienorenal shunt in a patient with noncirrhotic portal fibrosis.     

Scheme for detection of subcarrier modulated optical signals using switched parametric amplification

Switched parametric amplification is used to amplify detected subcarrier modulated fibre-opt)c signals. A large gain of the order of 23 dB has been easily obtained, and the distortion is found to be below 25 dB over an input signal range of 20 dB.     

35 GHz dielectric resonator stabilised gunn oscillator

A 35 GHz dielectric resonator oscillator(DRO) using GaAs Gunn diode in microstrip configuration has been designed and developed. The oscillator, with an integral waveguide-to-microstrip transition, delivered an output greater than 18 dBm. Phase noise of the oscillator is found to be better than ?80 dBc/Hz at 100 KHz away from the carrier. A frequency drift of about ±25 MHz has been observed over the temperature range from ?10 °C to 50 °C.     

Development of moderate temperature CVD Al2O3 coatings

Chemically vapor deposited Al₂O₃ coatings, due to their high hardness and chemical inertness, are currently the state of art in the cutting tool industry. The conventional high deposition temperature of about 1050 °C for Al₂O₃ coatings, based on the water–gas shift process, has to a great extend restricted the development of several hybrid coatings, such as TiC/TiN/TiCN/Al₂O₃. To overcome this limitation, alternate systems to deposit Al₂O₃ at moderate temperatures have been investigated. Systems using NO–H₂, H₂O₂, NO₂–H₂ and HCOOH were identified and thermodynamic calculations were performed to evaluate them as potential sources of oxygen donors to form Al₂O₃ in the moderate temperature range of 700–950 °C. Preliminary results have clearly demonstrated that it is possible to grow moderate temperature alumina (using such alternate sources) on the TiC/TiN coated cemented carbide substrates.     

Computationally efficient variational Bayesian method for PAPR reduction in multiuser MIMO‐OFDM systems

This paper investigates the use of the inverse‐free sparse Bayesian learning (SBL) approach for peak‐to‐average power ratio (PAPR) reduction in orthogonal frequency‐division multiplexing (OFDM)‐based multiuser massive multiple‐input multiple‐output (MIMO) systems. The Bayesian inference method employs a truncated Gaussian mixture prior for the sought‐after low‐PAPR signal. To learn the prior signal, associated hyperparameters and underlying statistical parameters, we use the variational expectation‐maximization (EM) iterative algorithm. The matrix inversion involved in the expectation step (E‐step) is averted by invoking a relaxed evidence lower bound (relaxed‐ELBO). The resulting inverse‐free SBL algorithm has a much lower complexity than the standard SBL algorithm. Numerical experiments confirm the substantial improvement over existing methods in terms of PAPR reduction for different MIMO configurations.     

Feasibility studies of large scale production of human anti-tetanus toxoid monoclonal antibodies

The feasibility of large scale production of human anti-tetanus toxoid monoclonal antibody for therapeutic use was evaluated using a human heterohybridoma. The effects of duration of subculture, transition from static to agitated culture conditions and the level of serum concentration were studied. The level of antibody secreted by the clone decreased with increasing length of subculture and decreasing serum concentration. The clone exhibited heterogeneity in expression of surface IgG after 2 or 7 weeks of subculture in static culture conditions irrespective of the serum concentration. However, a prolonged duration of subculture (9 weeks) in 3% serum medium had an effect on the expression of surface IgG both in static and agitated culture conditions. With respect to total (surface and intracellular) IgG, two distinct cell populations were observed. On long term subculture (9 weeks) in low serum medium (3% FCS), there was a decrease in the population which was the high synthesizer. In addition, when these cells were cultivated in agitated spinner flasks, a defect in secretion of antibodies was observed. Thus a general fall in the amount of antibody in the supernatant of agitated cultures was due to decrease in antibody synthesis as well as the defect in secretion of antibodies.     

Development of ashless multifunctional additives from cashew nutshell liquid

Aminodi(alkylphenyl) phosphorodithioates have been synthes‐ised by the condensation of di (alkylphenyl) phosphorodithioic acid, which was derived from a renewable, biodegradable, low‐cost, naturally occurring vegetable product, cashew nutshell liquid, with various amines. These ashless aminodi (alkyl‐phenyl) phosphorodithioates have been evaluated as anti‐oxidant, antiwear, friction‐modifying, and extreme‐pressure additives in lubricant compositions.