Functional Imaging Using InGaAs/GaAs Photorefractive Multiple Quantum Wells

doi:10.1063/1.1994722 http://link.aip.org/link/?APCPCS/772/1581/1We propose the use of an InGaAs/GaAs photorefractive quantum well (PRQW) as an adaptive beam combiner for holographic optical coherence imaging applications. Holograms have been observed by using a diode laser and an interferometer. A weaker quantum confined exciton leads to the saturation of electroabsorption and hence diffraction, under a high external electric field, in the InGaAs PRQW. A careful choice of external electric field modulation seems to reduce this effect. We examine several characteristics that govern the use of an InGaAs PRQW in a functional imaging system

Will He Be There?: Mediating malaria, immobilizing science

This paper focuses on an unsettling example of experimental labour – the Human Landing Catch (HLC). The HLC is a cheap and reliable technique to produce data on mosquito densities in a defined area. It requires only a human volunteer to sit over night with his legs exposed, a headlamp to spot mosquitoes, and a rubber tube and plastic cup to catch them as they come to feed on him. The HLC formed the central methodological and operational strategy for a malaria control that took place in Dar es Salaam, funded by the Bill and Melinda Gates Foundation. This paper analyses the epistemic and economic value of this experimental scenario by examining in detail the work it entails. In conceptualizing the different species of productivity associated with the HLC, of particular interest is the surprising fact that he is there. This paper argues that the interplay of mobility and immobility offers a way to rethink the value of research within interlocking circulations of capital, science, mosquitoes and men

Governing stem cell therapy in India: regulatory vacuum or jurisdictional ambiguity?

Stem cell treatments are being offered in Indian clinics although preclinical evidence of their efficacy and safety is lacking. This is attributed to a governance vacuum created by the lack of legally binding research guidelines. By contrast, this paper highlights jurisdictional ambiguities arising from trying to regulate stem cell therapy under the auspices of research guidelines when treatments are offered in a private market disconnected from clinical trials. While statutory laws have been strengthened in 2014, prospects for their implementation remain weak, given embedded challenges of putting healthcare laws and professional codes into practice. Finally, attending to the capacities of consumer law and civil society activism to remedy the problem of unregulated treatments, the paper finds that the very definition of a governance vacuum needs to be reframed to clarify whose rights to health care are threatened by the proliferation of commercial treatments and individualized negligence-based remedies for grievances

On centralizer algebras for spin representations

We give a presentation of the centralizer algebras for tensor products of spinor representations of quantum groups via generators and relations. In the even-dimensional case, this can be described in terms of non-standard q-deformations of orthogonal Lie algebras; in the odd-dimensional case only a certain subalgebra will appear. In the classical case q = 1 the relations boil down to Lie algebra relations

Finite difference lattice Boltzmann model with flux limiters for liquid-vapor systems

In this paper we apply a finite difference lattice Boltzmann model to study the phase separation in a two-dimensional liquid-vapor system. Spurious numerical effects in macroscopic equations are discussed and an appropriate numerical scheme involving flux limiter techniques is proposed to minimize them and guarantee a better numerical stability at very low viscosity. The phase separation kinetics is investigated and we find evidence of two different growth regimes depending on the value of the fluid viscosity as well as on the liquid-vapor ratio.Comment: 10 pages, 10 figures, to be published in Phys. Rev.

Management of Multi Drug Resistance Tuberculosis in the Field: Tuberculosis Research Centre Experience

Setting: Multi-drug TB resistant (resistant to isoniazid and rifampicin) patients identified from a rural and urban area. Objective: To study the feasibility of managing MDR TB patients under field conditions where DOTS programme has been implemented Methods: MDR TB Patients identified among patients treated under DOTS in the rural area and from cases referred by the NGO when MDR TB was suspected form the study population. Culture and drug susceptibility testing were done at Tuberculosis Research Centre (TRC). Treatment regimen was decided on individual basis. After a period of initial hospitalization, treatment was continued in the respective peripheral health facility or with the NGO after identifying a DOT provider in the field. Patients attended TRC at monthly intervals for clinical, sociological and bacteriological evaluations. Drugs for the month were pre-packed and handed over to the respective center. Results: A total of 66 MDR TB patients (46 from the rural and 20 from the NGO) started on treatment form the study population and among them 20 (30%) were resistant to one or more second line drugs (Eto, Ofx, Km) including a case of “XDR TB”. Less than half the patients stayed in the hospital for more than 10 days. The treatment was provided partially under supervision. Providing injection was identified to be a major problem. Response to treatment could be correctly predicted based on the 6-month smear results in 40 of 42 regular patients. Successful treatment outcome was observed only in 37% of cases with a high default of 24%. Adverse reactions necessitating modification of treatment was required only for three patients. Implications Despite having reliable DST and drug logistics, the main challenge was to maintain patients on such prolonged treatment by identifying a provider closer to the patient who can also give injection, have social skills and manage of minor adverse reactions

Zoo-chemical profile analysis and cytotoxicity screening of five marine sponge species collected from Andaman and Nicobar Islands

1464-1472Marine environment with vast diversity is a great natural source of many important bioactive compounds of medicinal value. In the present study, five marine sponges i.e. Hyrtios erectus, Pseudoceratina purpurea, Carteriospongia foliascens, Stylissa carteri and Axinella acanthelloides were collected from eastern coast of Andaman sea around South Andaman group of islands and their zoo-chemical profiles were analyzed. The in-vitro cytotoxic potential of the five sponge species against breast carcinoma cell line was evaluated. Alkaloid was the major zoo-chemical constituent of the sponges. Among the five sponge species studied, Hyrtios showed most promising cytotoxic effect against breast carcinoma cell line. Hexane extract of sponge inhibited the proliferation of the MCF-7 cell line. IC50 value was 25 µg per ml. The IC50 values of all the solvent extracts of all the four sponges were higher than 100 µg per ml. In conclusion, the sponge Hyrtios has huge pharmaceutical potential in the treatment of breast cancer

Profitable failure: antidepressant drugs and the triumph of flawed experiments

Drawing on an analysis of Irving Kirsch and colleagues? controversial 2008 article in PLoS [Public Library of Science] Medicine on the efficacy of SSRI antidepressant drugs such as Prozac, I examine flaws within the methodologies of randomized controlled trials (RCTs) that have made it difficult for regulators, clinicians and patients to determine the therapeutic value of this class of drug. I then argue, drawing analogies to work by Pierre Bourdieu and Michael Power, that it is the very limitations of RCTs ? their inadequacies in producing reliable evidence of clinical effects ? that help to strengthen assumptions of their superiority as methodological tools. Finally, I suggest that the case of RCTs helps to explore the question of why failure is often useful in consolidating the authority of those who have presided over that failure, and why systems widely recognized to be ineffective tend to assume greater authority at the very moment when people speak of their malfunction