Sensitivity Analysis of Calibration Methods and Factors Effecting the Statistical Nature of Radiation Measurement

The scintillator detectors are recalibrated against the datasheet given by the manufacturer. Optimal and mutual dependent values of (a) high voltage at PMT (Photomultiplier Tube), (b) amplifier gain, (c) average time to count the radiation particles (set by operator), and (d) number of instances/sample number are estimated. Total 5: two versions of Central Limit Theorem (CLT), (3) industry preferred Pulse Width Saturation, (4) calibration based on MPPC coupled Gamma-ray detector, and (5) gross method are used. It is shown that the CLT method is the most optimal method to calibrate the detector and its respective electronics couple. An inverse modeling-based Computerized Tomography method is used for verification. It is shown that statistically averaging results are more accurate and precise data than mode and median if the data is not skewed and a random number of samples are used during the calibration process. It is also shown that the average time to count the radiation particle is the most important parameter affecting the optimal calibration setting for precision and accurate measurements of gamma radiation.

     

Premature separation of centromere and aneuploidy: an indicator of high risk in unaffected individuals from familial breast cancer families?

OBJECTIVES: Injury is the leading cause of death in the male working population of Brazil. An important fraction of these deaths are work related. Very few cohort studies of steel workers, and none from developing countries, have reported on mortality from injuries. This paper analyses mortality from work and non-work related injuries among Brazilian steel workers. METHODS: Deaths during employment from 1 January 1977 to 30 November 1992 were analysed in a cohort of 21,816 male steel workers. Mortality rates specific for age and calendar year among the workers were compared with those of the male population of the state where the plant is located. Work related injuries were analysed by comparing the mortality rates for different subgroups of the cohort. RESULTS: The number of deaths (391) was less than half that expected based on death rates of the general population. Over 60% (242) of deaths were due to injuries. Mortality from most causes was substantially below that in the general population, but that from unintentional injury, was 50% above that of the general population. Standardised mortality ratios (SMRs) were highest for the youngest and the oldest employees and for labourers and clerical workers. Mortality from motor vehicle injury was twice that expected from population rates (SMR = 209, 95% confidence interval (95% CI) 176-244). There was a 67% fall in the age adjusted mortality from occupational injuries in the study period. CONCLUSION: The healthy worker effect in this cohort was greater than that commonly found in studies of occupational groups in developed countries, probably because of a greater socioeconomic gap between employed and unemployed populations in Brazil, and unequal distribution of health care resources. Mortality was especially high for motor vehicle injuries. The fall in mortality from occupational injuries during the study period was probably due to improvement in safety standards, increased automation, and better medical care. There is a need to investigate risk factors for unintentional injuries among steel workers, especially those due to motor vehicle injuries. Prevention of occupational and nonoccupational injuries should be a main priority in Brazil.     

Production of agrochemical from waste polyesters

In this study, agrochemical was produced from waste polyesters. Reactions of waste polyesters [poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT)] powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol lead acetate as a catalyst were carried out in a batch reactor at 470 K and at atmospheric pressure conditions. Reactions were undertaken with various particle size ranges from 50 to 512.5 μm, and reaction time from 30 to 70 min for reactions of polyesters. Low molecular weight product of polyester was obtained during this process. In the next stage, hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide (KOH) solution were introduced to convert low molecular weight product of polyester into terephthalohydroxamic acid (TPHA) by introduction of HCl (Hydrochloric Acid) as per stoichiometric requirement. TPHA can be used as an agrochemical (insecticide) with appreciable efficiency. To increase the polyester conversion rate, external catalyst (0.003 mol lead acetate) was introduced during the reaction. The product was deposited on the surface of unreacted polyester, which was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate, DMSO, CHA, and THF were introduced during the reaction, which has an industrial significance. Depolymerization of polyester was proportional to the reaction time. Depolymerization of polyester was inversely proportional to the particle size of polyester. Analyses of value‐added product (TPHA) and byproducts [EG and BD (1,4‐butanediol)] as well as polyesters were undertaken. A kinetic model is developed, and experimental data simulated with it, which was consistent with the model. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2504–2510, 2006     

Metronidazole-loaded nanostructured lipid carriers to improve skin deposition and retention in the treatment of rosacea

The objective of the present investigation was to improve the skin deposition and retention of metronidazole (MTZ) in rosacea therapy by incorporating it into nanostructured lipid carriers (NLCs). The main challenge in this endeavor was the partial hydrophilicity of MTZ, which mandated careful selection of excipients, including solid and liquid lipids, surfactants, and their ratios in combination. NLCs were produced by the phase inversion temperature method and finally converted into a gel for topical application. The prepared nanoparticles were evaluated for their particle size, zeta potential, entrapment efficiency, solid-state characteristics, surface morphology, in vitro drug release, and permeation through excised skin. The gel was additionally characterized for its pH, drug content, viscosity, and spreadability. The prepared nanoparticles were spherical in shape and of size less than 300?nm. Incorporation of judiciously chosen excipients made possible a relatively high entrapment efficiency of almost 40%. The drug release was found to be biphasic, with an initial burst release followed by sustained release up to 8?hours. In comparison to the plain drug gel, which had a tissue deposition of 11.23%, the NLC gel showed a much superior and desirable deposition of 26.41%. The lipophilic nature of the carrier, its size, and property of occlusion enabled greater amounts of drug to enter and be retained in the skin, simultaneously minimizing permeation through the skin, i.e. systemic exposure. The results of the study suggest that NLCs of anti-rosacea drugs have the potential to be used in the therapy of rosacea.     

Effect of Nd3+ substitution on structural and magnetic properties of Mg–Cd ferrites synthesized by microwave sintering technique

Nd~(3+) substituted spinel ferrites with formula Mg_xCd_(1-x)Nd_(0.03)Fe_(1.97)O_4(x = 0.0.2,0.4,0.6.0.8 and 1.0)were prepared by oxalate co-precipitation method using novel microwave sintering technique. AR grade sulphates were used as starting chemicals. The samples were sintered at optimized power of 70 W for10 min in a microwave oven(800 W). The structural analysis of these samples was done by using X-ray diffraction, scanning electron microscope and Fourier transform IR techniques. The XRD analysis of the synthesized ferrite confirms the formation of cubic spinel structure of ferrite. The influence of Nd3+substitution on various structural parameters of Mg-Cd ferrites was reported. IR study indicates the spectra contain two intense absorption bands around 600 and 400 cm~(-1) in addition with four extra bands. The magnetic properties of all ferrites were studied by using a vibration sample magnetometer.The crystallite and grain size dependant magnetic properties are observed. The composition Mg_(0.6)Cd_(0.4)Nd_(0.03)Fe_(1.97)O_4 has better magnetic properties that can be used in recording media. The fast synthesis of spinel ferrites is yielded due to use of the microwave sintering technique.     

Modelling of nanostructured TiO2-based memristors

The fourth fundamental circuit element memristor completes the missing link between charge and magnetic flux. It consists of the function of the resistor as well as memory in nonlinear fashion. The property of the memristor depends on the magnitude and direction of applied potential. This unique property makes it the primitive building block for many applications such as resistive memories, soft computing, neuromorphic systems and chaotic circuits etc. In this paper we report TiO2-based nanostructured memristor modelling. The present memristor model is constructed in MATLAB environment with consideration of the linear drift model of memristor. The result obtained from the linear drift model is well matched with earlier reported results by other research groups.     

Photocatalytic degradation of RhB and TNT and photocatalytic water splitting with CZTS microparticles

Cu₂ZnSnS₄ (CZTS) is a main candidate material for solar energy conversion through both photovoltaics and photocatalysis based on environmentally friendly elements and with a direct band gap of 1.5 eV. We report the synthesis of quasi Cu₂ZnSnS₄ microparticles with unprecedented narrow size distributions. The structural, morphological and core level analysis has been carried out by XRD, SEM and XPS techniques. These microparticles have shown excellent photocatalytic activity toward degradation of Rhodamine B dye (RhB) and TNT under visible light. The extent of mineralization has been analyzed by COD and TOC values. Photocatalytic water splitting for H₂ generation has also been reported.