Issues on human acceleration tolerance after long-duration space flights

This report reviewed the literature on human tolerance to acceleration at 1 G and changes in tolerance after exposure to hypogravic fields. It was found that human tolerance decreased after exposure to hypokinetic and hypogravic fields, but the magnitude of such reduction ranged from 0 to 30 percent for plateau G forces and 30 to 70 percent for time tolerance on sustained G forces. A logistic regression model of the probability of individuals with 25 percent reduction in +Gz tolerance after 1 to 41 days of hypogravic exposures was constructed. The estimated values from the model showed a good correlation with the observed data. A brief review of the need for in-flight centrifuge during long-duration missions was also presented. Review of the available data showed that the use of countermeasures (such as anti-G suits, periodic acceleration, and exercise) reduced the decrement in acceleration tolerance after long-duration space flights. Areas of further research include quantification of the effect of countermeasures on tolerance, and methods to augment tolerance during and after exposures to hypogravic fields. Such data are essential for planning long-duration human missions

Risk of decompression sickness in the presence of circulating microbubbles

In this study, we examined the association between microbubbles formed in the circulation from a free gas phase and symptoms of altitude decompression sickness (DCS). In a subgroup of 59 males of mean (S.D) age 31.2 (5.8) years who developed microbubbles during exposure to 26.59 kPa (4.3 psi) under simulated extravehicular activities (EVA), symptoms of DCS occurred in 24 (41 percent) individuals. Spencer grade 1 microbubbles occurred in 4 (7 percent), grade 2 in 9 (15 percent), grade 3 in 15 (25 percent), and grade 4 in 31 (53 percent) of subjects. Survival analysis using Cox proportional hazards regression showed that individuals with less than grade 3 CMB showed 2.46 times (95 percent confidence interval = 1.26 to 5.34) higher risk of symptoms. This information is crucial for defining the risk of DCS for inflight Doppler monitoring under space EVA. Altitude decompression sickness (DCS) occurs when there is acute reduction in ambient pressure. The symptoms of DCS are due to the formation of a free gas phase (in the form of gas microbubbles) in tissues during decompression. Musculo-skeletal pain of bends is the commonest form of DCS in altitude exposures. In the space flight environment, there is a risk of DCS when astronauts decompress from the normobaric shuttle pressure into the hypobaric space suit pressure (currently about 29.65 kPa (4.3 psi) for extra-vehicular activities (EVA). This risk is counterbalanced by a judicious combination of prior denitrogenation and staged decompression. Studies of DCS are limited by the duration of the test at reduced pressure. Since only a proportion of subjects tested develop symptoms, the information on DCS is generally incomplete or 'censored'. Many studies employ Doppler ultrasound monitoring of the precordial area for detecting circulating microbubbles (CMB). Although the association between CMB and bends pain is not causal, CMB are frequently monitored during decompression. In this paper, we examine the association between CMB and symptoms of DCS under simulated EVA profiles

Analysis of the individual risk of altitude decompression sickness under repeated exposures

In a case-control study, researchers examined the risk of decompression sickness (DCS) in individual subjects with higher number of exposures. Of the 126 subjects, 42 showed one or more episodes of DCS. Examination of the exposure-DCS relationship by odds ratio showed a linear relationship. Stratification analysis showed that sex, tissue ratio, and the presence of Doppler microbubbles were cofounders of this risk. A higher number of exposures increased the risk of DCS in this analysis

High temperature CO2 sorption using Ca(OH)2 in pilot scale packed column

Carbon dioxide is the major content of greenhouse gases, which is released by many industries such as paper, cement and steel industries etc. Removal or separation of CO2 from the atmosphere is a challenging task for the researchers as it related to the human health and affects environment. Many methods and techniques have been tried for the removal of CO2, among them sorption method was found to be more simple and economical. Majority of research work related to CO2 sequestration was carried out using Thermo Gravimetric Analysis (TGA). In the present study an attempt was made to study high temperature CO2 sorption using self-fabricated packed bed column in pilot scale. In this work the absorption column was designed to utilize the flue gas temperature for effective sorption of carbon dioxide using Calcium hydroxide [Ca(OH)2] as a sorbent. The Ca(OH)2 was made into cylindrical extrudates. The gas mixture containing nitrogen and carbon dioxide was heated and subjected to CO2 sorption using Ca(OH)2. The sorption process for various temperatures was studied at a constant flow rate and fixed bed height. Concentration of CO2 was measured using a flue gas analyzer (NDIR sensors). The temperature was found to be major factor affecting sorption process. The optimum temperature was found to be 300 °C. Increase in the temperature above 300 °C, resulted in sintering and weight loss of the sorbent. The conversion of Ca(OH)2 to CaCO3 is confirmed by FT-IR, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis(EDAX) and XRD

Ethics Dumping – How not to do research in resource-poor settings

Ethics dumping is a global phenomenon involving the ‘off-shoring’of research. Research that would be prohibited, severely restrictedor regarded as highly patronizing in high-income regions is instead conducted inresource-poor settings. Twenty-eight case studies of ethics dumping were examined through inductive thematic analysis to reveal predisposing factors from the perspective of researchers from high-income regions. Six categories were agreed and further illuminated: Patronizing conduct, unfair distribution of benefits and/or burdens, culturally inappropriate conduct, double standards, lack of due diligence and lack of transparency. The ultimate aim of the paper is to deepen understanding of thesehighly unethical practicesamongst academics who stand against poverty, leading to theirfurther reduction

"Harnessing genomics to improve health in India" – an executive course to support genomics policy

BACKGROUND: The benefits of scientific medicine have eluded millions in developing countries and the genomics revolution threatens to increase health inequities between North and South. India, as a developing yet also industrialized country, is uniquely positioned to pioneer science policy innovations to narrow the genomics divide. Recognizing this, the Indian Council of Medical Research and the University of Toronto Joint Centre for Bioethics conducted a Genomics Policy Executive Course in January 2003 in Kerala, India. The course provided a forum for stakeholders to discuss the relevance of genomics for health in India. This article presents the course findings and recommendations formulated by the participants for genomics policy in India. METHODS: The course goals were to familiarize participants with the implications of genomics for health in India; analyze and debate policy and ethical issues; and develop a multi-sectoral opinion leaders' network to share perspectives. To achieve these goals, the course brought together representatives of academic research centres, biotechnology companies, regulatory bodies, media, voluntary, and legal organizations to engage in discussion. Topics included scientific advances in genomics, followed by innovations in business models, public sector perspectives, ethics, legal issues and national innovation systems. RESULTS: Seven main recommendations emerged: increase funding for healthcare research with appropriate emphasis on genomics; leverage India's assets such as traditional knowledge and genomic diversity in consultation with knowledge-holders; prioritize strategic entry points for India; improve industry-academic interface with appropriate incentives to improve public health and the nation's wealth; develop independent, accountable, transparent regulatory systems to ensure that ethical, legal and social issues are addressed for a single entry, smart and effective system; engage the public and ensure broad-based input into policy setting; ensure equitable access of poor to genomics products and services; deliver knowledge, products and services for public health. A key outcome of the course was the internet-based opinion leaders' network – the Indian Genome Policy Forum – a multi-stakeholder forum to foster further discussion on policy. CONCLUSION: We expect that the process that has led to this network will serve as a model to establish similar Science and Technology policy networks on regional levels and eventually on a global level

Selective Glitch Reduction Technique for Minimizing Peak Dynamic IR Drop

Abstract This paper proposes a glitch co mpensation technique which involves reducing glitch power in selected combinational cells to reduce peak current which contributes to dynamic voltage or IR drop. The proposed methodology can be seamlessly integrated to existing physical design flo ws. A glitch is an undesired transition that occurs before intended value in dig ital circuits. A glitch occurs in CMOS circu its when d ifferential delay at the inputs of a gate is greater than inertial delay, which results into increased gate switching and hence notable amount of power consumption. When such large nu mber of logic gates switch close to the same t ime they will contribute to power integrity challenge called pe ak dynamic IR drop. The glitch power is becoming more pro minent in lower technology nodes. Introduction of buffers at the input of the Logic gate may reduce glitches, but it results into large area overhead and dynamic power. In the proposed methodology we are using transmission gate as a compensation circuit to reduce extra leakage and dynamic power. A flo w is proposed for charactering the pass transistor logic to cater different delay values. The proposed methodology has been validated on a plac e and routed Multiply Accumulate (MA C) layout imp lemented using Synopsys SAED 9 0n m Generic library. Experimental results show 12% to 50% reduction in top 10 peak transient IR drop numbers with just 12% g litch power reduction in selected combinational cell instances. When compared to traditional on-chip decoupling capacitor (Decap) cells insertion method the proposed technique could reduce the peak IR drop numbers by the same amount with just 5% increase in total core capacitance

Targeted Deletion of Neuropeptide Y (NPY) Modulates Experimental Colitis

Neurogenic inflammation plays a major role in the pathogenesis of inflammatory bowel disease (IBD). We examined the role of neuropeptide Y (NPY) and neuronal nitric oxide synthase (nNOS) in modulating colitis.Colitis was induced by administration of dextran sodium sulphate (3% DSS) or streptomycin pre-treated Salmonella typhimurium (S.T.) in wild type (WT) and NPY (NPY(-/-)) knockout mice. Colitis was assessed by clinical score, histological score and myeloperoxidase activity. NPY and nNOS expression was assessed by immunostaining. Oxidative stress was assessed by measuring catalase activity, glutathione and nitrite levels. Colonic motility was assessed by isometric muscle recording in WT and DSS-treated mice.DSS/S.T. induced an increase in enteric neuronal NPY and nNOS expression in WT mice. WT mice were more susceptible to inflammation compared to NPY(-/-) as indicated by higher clinical & histological scores, and myeloperoxidase (MPO) activity (p<0.01). DSS-WT mice had increased nitrite, decreased glutathione (GSH) levels and increased catalase activity indicating more oxidative stress. The lower histological scores, MPO and chemokine KC in S.T.-treated nNOS(-/-) and NPY(-/-)/nNOS(-/-) mice supported the finding that loss of NPY-induced nNOS attenuated inflammation. The inflammation resulted in chronic impairment of colonic motility in DSS-WT mice. NPY -treated rat enteric neurons in vitro exhibited increased nitrite and TNF-alpha production.NPY mediated increase in nNOS is a determinant of oxidative stress and subsequent inflammation. Our study highlights the role of neuronal NPY and nNOS as mediators of inflammatory processes in IBD