Comparison of observed lung retention and urinary excretion of thorium workers and members of the public in India with the values predicted by the ICRP biokinetic model

The daily intake of natural Th and its contents in lungs, skeleton and liver of an Indian adult population group were estimated using radiochemical neutron activation analysis (RNAA) technique. These data on daily intake (through inhalation and ingestion) were used to compute Th contents in lungs and other systemic organs such as skeleton and liver using the new human respiratory tract model (HRTM) and the new biokinetic model of Th. The theoretically computed Th contents in lungs, skeleton and liver of an average Indian adult are 2.56, 4.00 and 0.17 microg, respectively which are comparable with the corresponding experimentally measured values of 4.31, 3.45 and 0.14 microg in an urban population group living in Mumbai. The measured lung contents of Th in a group of five occupational workers were used to compute their total body Th contents and the corresponding daily urinary excretions. The computed total body contents and daily urinary excretions of Th in the five subjects compared favourably with their measured values. These studies, thus, validate the new biokinetic model of Th in natural as well as in occupational exposures in Indian conditions.     

Capacity Theorems for the “Z” Channel

We consider the two-user "Z" channel (ZC), where there are two senders and two receivers. One of the senders transmits information to its intended receiver (without interfering with the unintended receiver), while the other sender transmits information to both receivers. The complete characterization of the discrete memoryless ZC remains unknown to date. For the Gaussian ZC, the capacity has only been established for a crossover link gain of 1. In this work, we study both the discrete memoryless ZC and the Gaussian ZC. We first establish achievable rates for the general discrete memoryless ZC. The coding strategy uses rate-splitting and superposition coding at the sender with information for both receivers. At the receivers, we use joint decoding. We then specialize the rates obtained to two different types of degraded discrete memoryless ZCs and also derive respective outer bounds to their capacity regions. We show that as long as a certain condition is satisfied, the achievable rate region is the capacity region for one type of degraded discrete memoryless ZC. The results are then extended to the two-user Gaussian ZC with different crossover link gains. We determine an outer bound to the capacity region of the Gaussian ZC with strong crossover link gain and establish the capacity region for moderately strong crossover link gain     

Novel down link rain fade mitigation technique for Ka‐band multibeam systems

Rain fades at Ka‐Band degrades the link quality and performance significantly. Several rain fade mitigation techniques for Ka‐band satellite systems are being investigated to improve the channel capacity. Methods such as power control and adaptive waveform techniques have been proposed for use in the uplink as they are capable of straightforward implementation. A novel down link power control technique for multi‐beam Ka‐band system has been proposed in this paper. It is based on the use of multi‐port amplifier, which is commonly used for dynamic power sharing of the beams depending upon the traffic. Payload architecture for multi‐beam coverage using multi‐port amplifiers has been designed for the proposed technique. The simulation results to compensate for the rain fade attenuation of one beam by sharing the unused power from other beams have been presented Copyright © 2006 John Wiley & Sons, Ltd.     

Isolicrung eines Nonicosapeptids aus Cheddar-K?se

Zusammenfassung Aus jungem Cheddar wurde durch Dialyse, Äthanol-Fällung, Gelchromatographie und Ionenaustauscher-Chromatographie ein Nonicosapeptid isoliert. Seine Brutto-Aminosäure-Zusammensetzung wird angegeben.

---

Isolation of a nonicosa-peptide from cheddar cheese

Summary A nonicosa-peptide was isolated from young Cheddar cheese via dialysis, ethanol precipitation, gel chromatography and ion exchange chromatography. Its amino acid composition is given.

     

Electroinitiated polymerization of benzonitrile

Summary The electroinitiated polymerization of benzonitrile yields a linear conjugated polymer, {ie421-01}(C₆H₅)C=N{ie421-02}. An anionic mechanism of polymerization is indicated.     

Osmotically controlled oral drug delivery

It is advantageous to deliver some drugs with short half-life, and which are to be given frequently for chronic ailments, in the form of controlled-release (CR) formulations. The orally administered drugs, in the form of conventional matrix or reservoir type formulations, pose problems of bioavailability fluctuations due to gastric pH variations. Moreover, the release of drug(s) from these systems is affected by the hydrodynamic conditions of the body. Osmotically controlled drug delivery systems utilize the principles of osmotic pressure for the controlled delivery of active agent(s). The release rate of drug(s) from these systems is independent of the physiological factors of the gastrointestinal (GI) tract to a large extent. In the present review, theory underlying the delivery of drugs from osmotic systems is presented. Different types of oral osmotic systems, their advantages over conventional matrix and reservoir types of systems, and their applications are also discussed. Finally, some of the limitations, adverse effects, and patent and market status of these systems are reviewed. These systems form a major segment of drug delivery products. Because of their advantages and strong market potential, it appears that the future of osmotic systems in rate-controlled oral drug delivery is promising.     

Electric arc deposition of carbon steel coatings with improved mechanical properties

To achieve high deposition rate and efficiency, electric arc spraying has been routinely used to deposit carbon steel coatings. Although retention of carbon in these coatings is poor due to the use of compressed air during spraying, the coatings are sufficiently hardened by brittle iron oxide inclusions to be suitable for hardfacing mechanical components used in mild adhesive and abrasive wear environments. However, carbon steel coatings can be employed for hardfacing mechanical components used in more aggressive wear environments, provided they are hardened by the carbon retention rather than by iron oxide inclu-sions. Therefore, to increase retention of carbon, reduce inclusion of iron oxides, and improve hardness and wear properties of carbon steel coatings, deposition experiments were carried out using an inexpen-sive nitrogen, which is produced on-site by a pressure swing adsorption or a membrane separation sys-tem, instead of compressed air during spraying.     

Partially Loaded Superimposed Training Scheme for Large MIMO Uplink Systems

This paper proposes a new superimposed training (ST) scheme for uplink multi-user multi-cell system, where each base station, equipped with a large number of antennas (M), communicates to single antenna users. In uplink training phase, large number of users within limited coherence time introduces the pilot contamination, which causes two types of interferences in data estimation. The first type, which is referred as self interference, arises due to the dependence between channel estimate and estimation error of the same user, while the second type, known as cross interference, occurs because of the correlation between ST vectors of different users. In this paper, an ST scheme with variable data length is proposed for Rician fading channels. For simplicity of analysis, a single cell model is considered first to derive mean squared error and signal to interference plus noise ratio. The analysis is further extended to multi-cell system. Various limiting cases are investigated, and the design parameters viz., power allocation factor and length of data vector, are optimized. Simulation results verify that the proposed ST scheme reduces self interference, and yields sum rate improvement over conventional ST scheme.     

Event Detection and Information Passing Using LEACH Protocol in Wireless Sensor Networks

Wireless Personal Communications - Wireless Sensor Networks plays an important role in creating and developing smart environments. It includes sensors geographically distributed which are...     

Fracture toughness of maraging steel from Charpy “V” notch specimens

Compact tension (CT) and Charpy V notch (CVN) (impact and three-point bend) specimens of 18 Ni 1800 MPa maraging steel (parent metal and weldment) were used to determine plane strain fracture toughness (K _IC) and CVN impact energy (CVNIE), respectively. Using an empirical equation,K _IC-CVNIE correlation is attempted which could be advantageously utilized for routine quality control of inward material to effect savings in cost and time. Investigations reveal betterK _IC-CVNIE correlation for tests using the precracked CVN specimens. Scanning electron microscopic (SEM) observations reveal good correlation between fractographic features and fracture toughness.