Idenpendent control of valence- and conduction-band states in composite quantum wells

iii+151hlm.;24c

Economic burden of asthma among patients visiting a private hospital in South India

Background: The presence of asthma is associated with a socioeconomic burden due to both direct and indirect cost. Aim: This study aims to estimate the economic burden of asthma in terms of direct and indirect cost as also determine if the proper control and adherence to medication would result in reduced cost. Materials and Methods: Direct cost was calculated in terms of medications, doctors visit, investigations, and hospitalizations. Indirect cost was calculated in terms of lost wages, termed as absenteeism. Asthma control was assessed using the asthma control test questionnaire. Results: A total of 120 patients were included; 69 males and 51 females. The mean annual direct cost for asthma treatment was ₹18,737/year. The mean annual cost due to medications, doctor's visit, investigations, and hospitalization was ₹7,427, ₹2089/year, ₹1103/year, and ₹62,500/year, respectively. An asthma patient lost an average of 17 working days/year. The mean annual indirect cost for an asthma patient was ₹25,358, whereas, for the caregivers was ₹19,971. About 47.5% of patients had well-controlled asthma and 52.5% of patients had uncontrolled asthma. The mean annual direct cost among controlled and uncontrolled asthma patients were ₹13,010 and ₹23,918, respectively. Fifty-seven percent of patients were compliant with medication. The mean annual direct cost among compliant and non-compliant patients was ₹14,401 and ₹24,407, respectively. Percentage of hospitalization was less among the compliant group (6%) when compared with noncompliant group (17%). Conclusion: Asthma is not only associated with patient-specific impairment but also a significant economic burden to the family and society. Loss of productivity is another underappreciated source of economic loss

Photoacoustic study on photobleaching of Rhodamine 6G doped in poly(methyl methacrylate)

The photobleaching of the lasing dye Rhodamine 6G embedded in the solid matrix poly(methyl methacrylate) was investigated using a photoacoustic technique. Chopped laser radiation from an argon ion laser at four different wavelengths was used for the study. Experimental results indicate that the photobleaching rate is directly proportional to the incident laser power while it decreases with increase in concentration of the dye molecules. In the present case we have not observed any dependence of photobleaching on the chopping frequency. One-photon absorption is found to be responsible for the photobleaching of the dye within the selected range of laser power

Not Available

Not AvailableNot AvailableNot Availabl

Photoacoustic study on photobleaching of Rhodamine 6G doped in poly(methyl methacrylate)

The photobleaching of the lasing dye Rhodamine 6G embedded in the solid matrix poly(methyl methacrylate) was investigated using a photoacoustic technique. Chopped laser radiation from an argon ion laser at four different wavelengths was used for the study. Experimental results indicate that the photobleaching rate is directly proportional to the incident laser power while it decreases with increase in concentration of the dye molecules. In the present case we have not observed any dependence of photobleaching on the chopping frequency. One-photon absorption is found to be responsible for the photobleaching of the dye within the selected range of laser powe

Photoacoustic investigation of intrinsic and extrinsic Si

An open-cell configuration of the photoacoustic (PA) technique is employed to determine the thermal and transport properties of intrinsic Si and Si doped with B (p-type) and P (n-type). The experimentally obtained phase of the PA signal under heat transmission configuration is fitted to that of theoretical model by taking thermal and transport properties, namely, thermal diffusivity, diffusion coefficient, and surface recombination velocity, as adjustable parameters. It is seen from the analysis that doping and also the nature of dopant have a strong influence on the thermal and transport properties of semiconductors. The results are interpreted in terms of the carrier-assisted and phonon-assisted heat transfer mechanisms in semiconductors as well as the various scattering processes occurring in the propagation of heat carriers.Cochin University of Science and Technolog

Photoacoustic spectrum of samarium phthalocyanine powder

Photoacoustic spectrum of samarium phthalocyanine powder is recorded and compared with previously reported UV–vis absorption spectra of the same dissolved in different liquid and solid host media. The Davidov splitting of Q band is observed in the PA spectrum but the two bands are overlapped considerably and the shorter wavelength band is more intense and dominating one in the powder spectrum.Cochin University of Science and Technolog

A microbent fiber optic pH sensor

Optical fiber sensors developed for measuring pH values usually employ an unclad and unstrained section of the fiber. In this paper, we describe the design and fabrication of a microbent fiber optic sensor that can be used for pH sensing. In order to obtain the desired performance, a permanently microbent portion of a plastic optic fiber is coated with a thin film of dye impregnated sol–gel material. The measurements are simultaneously carried out in two independent detection schemes viz., the bright field detection configuration for detecting the core modes and dark field detection configuration, for detecting the cladding modes. The results of measurements of core mode-power and cladding mode-power variation with change in pH of a solution surrounding the coated portion of the fiber is presented. This paper thus demonstrates how a bare plastic fiber can be modified for pH sensing in a simple and cost effective manner.Cochin University of Science and Technology & Technical University of Eindhove