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Background: \ud \ud Most people with stroke in India have no access to organised rehabilitation services. The effectiveness of training family members to provide stroke rehabilitation is uncertain. Our primary objective was to determine whether family-led stroke rehabilitation, initiated in hospital and continued at home, would be superior to usual care in a low-resource setting.\ud \ud Methods: \ud \ud The Family-led Rehabilitation after Stroke in India (ATTEND) trial was a prospectively randomised open trial with blinded endpoint done across 14 hospitals in India. Patients aged 18 years or older who had had a stroke within the past month, had residual disability and reasonable expectation of survival, and who had an informal family-nominated caregiver were randomly assigned to intervention or usual care by site coordinators using a secure web-based system with minimisation by site and stroke severity. The family members of participants in the intervention group received additional structured rehabilitation training—including information provision, joint goal setting, carer training, and task-specific training—that was started in hospital and continued at home for up to 2 months. The primary outcome was death or dependency at 6 months, defined by scores 3–6 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) as assessed by masked observers. Analyses were by intention to treat. This trial is registered with Clinical Trials Registry-India (CTRI/2013/04/003557), Australian New Zealand Clinical Trials Registry (ACTRN12613000078752), and Universal Trial Number (U1111-1138-6707).\ud \ud Findings: \ud \ud Between Jan 13, 2014, and Feb 12, 2016, 1250 patients were randomly assigned to intervention (n=623) or control (n=627) groups. 33 patients were lost to follow-up (14 intervention, 19 control) and five patients withdrew (two intervention, three control). At 6 months, 285 (47%) of 607 patients in the intervention group and 287 (47%) of 605 controls were dead or dependent (odds ratio 0·98, 95% CI 0·78–1·23, p=0·87). 72 (12%) patients in the intervention group and 86 (14%) in the control group died (p=0·27), and we observed no difference in rehospitalisation (89 [14%]patients in the intervention group vs 82 [13%] in the control group; p=0·56). We also found no difference in total non-fatal events (112 events in 82 [13%] intervention patients vs 110 events in 79 [13%] control patients; p=0·80).\ud Interpretation: \ud \ud Although task shifting is an attractive solution for health-care sustainability, our results do not support investment in new stroke rehabilitation services that shift tasks to family caregivers, unless new evidence emerges. A future avenue of research should be to investigate the effects of task shifting to health-care assistants or team-based community care.\ud \ud Funding: \ud \ud The National Health and Medical Research Council of Australia.

International audience; Here we study the optimum efficiency of the excitation of maximum quantum (MaxQ) coherence using analytical and numerical methods based on optimal control theory. The theoretical limit of the achievable MaxQ amplitude and the minimum time to achieve this limit are explored for a set of model systems consisting of up to five coupled spins. In addition to arbitrary pulse shapes, two simple pulse sequence families of practical interest are considered in the optimizations. Compared to conventional approaches, substantial gains were found both in terms of the achieved MaxQ amplitude and in pulse sequence durations. For a model system, theoretically predicted gains of a factor of three compared to the conventional pulse sequence were experimentally demonstrated. Motivated by the numerical results, also two novel analytical transfer schemes were found: Compared to conventional approaches based on non-selective pulses and delays, double-quantum coherence in two-spin systems can be created twice as fast using isotropic mixing and hard spin-selective pulses. Also it is proved that in a chain of three weakly coupled spins with the same coupling constants, triple-quantum coherence can be created in a time-optimal fashion using so-called geodesic pulses.

In this investigation, four local inbred maize (Zea mays L.) genotypes CM-500, NAI-127, NAI-129 and SKV-10 were evaluated in the field against Peronosclerospora sorghi during two seasons, i.e., Kharif and Rabi, 2005. The results indicate that genotype SKV-10 was found highly resistant to downy mildew recording 1.0% of disease during both seasons. Whereas NAI-129 had low incidence (10.2 and 13.0% respectively for Kharif and Rabi) of downy mildew compared to CM-500 (97.2 and 99.4% respectively for Kharif and Rabi). The characterization of soluble seed proteins by SDS-PAGE indicates CM-500 as highly susceptible to downy mildew and revealed considerable variation among the genotypes. It is evident from the dendrograms that CM-500 and NAI-127, as well as NAI-129 and SKV-10, were genetically closely related, consistent with the compatible and incompatible reaction of these genotypes to downy mildew.

Nocturnal enuresis is a common problem affecting school-aged children worldwide. Although it has significant impact on child's psychology, it is always under-recognized in India and considered as a condition which will outgrow with advancing age. Nocturnal enuresis classified as primary or secondary and monosymptomatic or nonmonosymptomatic. Factors that cause enuresis include genetic factors, bladder dysfunction, psychological factors, and inappropriate antidiuretic hormone secretion, leading to nocturnal polyuria. Diagnosis consists of detailed medical history, clinical examination, frequency-volume charts, and appropriate investigations. The frequency-volume chart or voiding diary helps in establishing diagnosis and tailoring therapy. The first step in treating nocturnal enuresis is to counsel the parents and the affected child about the condition and reassure them that it can be cured. One of the effective strategies to manage enuresis is alarm therapy, but currently, it is not easily available in India. Desmopressin has been used in the treatment of nocturnal enuresis for close to 50 years. It provides an effective and safe option for the management of nocturnal enuresis. This review covers the diagnosis and management of nocturnal enuresis and introduces the concept of “bedwetting clinics” in India, which should help clinicians in the thorough investigation of bedwetting cases.

Growing skull fractures are rare complications of head injury, occurring almost exclusively in infants and children under the age of three. A retrospective review at our Institute yielded 41 patients with this entity over a period of 20 years (1975-1995). The age at presentation ranged from less than 1 year to 62 years, with 33 (80.5%) patients being less than 5 years of age. The cause of injury was either a fall from a height (93%) or a road traffic accident. The most common location of a growing skull fracture was either parietal or frontoparietal (56%). One patient had a posterior fossa growing skull fracture. CT scan was performed in 19 patients which demonstrated an underlying porencephalic cyst, hydrocephalus or a cyst communicating with the ventricle. In 5 children, a ventriculo-peritoneal shunt alone was performed. Twenty four patients underwent a duro- and cranioplasty while a duroplasty alone was performed in 8 patients. The material used for cranioplasty included acrylic, wire mesh, steel plates or autologous bone. Three patients died, one due to an anaesthetic complication and two as a result of postoperative meningitis. Post-operative CSF leaks occurred in 3 patients, which were managed by a lumbar drain. Six patients had local wound infection.

Real gas effects dominate the hypersonic flow fields encountered by modern day hypersonic space vehicles. Measurement of aerodynamic data for the design applications of such aerospace vehicles calls for special kinds of wind tunnels capable of faithfully simulating real gas effects. A shock tunnel is an established facility commonly used along with special instrumentation for acquiring the data for this purpose within a short time period. The hypersonic shock tunnel (HST1), established at the Indian Institute of Science (IISc) in the early 1970s, has been extensively used to measure the aerodynamic data of various bodies of interest at hypersonic Mach numbers in the range 4 to 13. Details of some important measurements made during the period 1975–1995 along with the performance capabilities of the HST1 are presented in this review. In view of the re-emergence of interest in hypersonics across the globe in recent times, the present review highlights the suitability of the hypersonic shock tunnel at the IISc for future space application studies in India.

A study of transpiration cooling of blunt bodies such as a hemicylinder is made by solving Navier-Stokes equations. An upwind, implicit time-marching code is developed for this purpose. The study is conducted for both perfect-gas and real-gas (chemical equilibrium) flows. Investigations are carried out for a special wall condition that is referred to as no heat flow into the wall condition. The effects of air injection on wall temperature are analyzed. Analyses are carried out for Mach numbers ranging between 6-10 and Reynolds numbers ranging between 10(6)-10(7). Studies are made for spatially constant as well as spatially varying mass injection rate distributions, White cold air injection reduces the wall temperature substantially, transpiration cooling is relatively less effective when the gas is in chemical equilibrium.

Transpiration cooling over a flat plate at hypersonic Mach numbers is analyzed using Navier-Stokes equations, without the assumption of an isothermal wall with a prescribed wall temperature. A new criterion is proposed for determining a relevant range of blowing rates, which is useful in the parametric analysis. The wall temperature is found to decrease with the increasing blowing rate, but this effect is not uniform along the plate. The effect is more pronounced away from the leading edge. The relative change in the wall temperature is affected stronger by blowing at high Reynolds numbers. (AIAA)

This review will describe about the loop mediated isothermal amplification (LAMP) and its advantages in detection of opportunistic infections in HIV infected individuals. HIV infection is the strongest risk factor for development of tuberculosis (TB) and Cytomegalovirus (CMV) conversely both TB and CMV are the commonest HIV-associated opportunistic diseases worldwide. Loop-mediated isothermal amplification (LAMP) can amplify DNA with high specificity, efficiency and rapidity under isothermal condition. One of the great advantages of the LAMP assay is that amplification can be monitored with the naked eye using SYBR green dye. This sort of detection system is easy and helpful in discriminating infectious and non infectious samples. In view of the advantages of rapid amplification, and easy detection, LAMP has potential applications for clinical diagnosis in developing countries without requiring experienced persons and sophisticated equipment.

Analysis of gas-particle nozzle flow is carried out with attention to the effect of dust particles on the vibrational relaxation phenomena and consequent effects on the gain of a gasdynamic laser. The phase nonequilibrium between the gas mixture and the particles during the nozzle expansion process is taken into account simultaneously. The governing equations of the two-phase nozzle flow have been transformed into similar form, and general correlating parameters have been obtained. It is shown from the present analysis that the particles present in the mixture affect the optimum gain obtainable from a gasdynamic laser adversely, and the effect depends on the size and loading of the particles in the mixture.

KNOWLEDGE of surface heat transfer rates for a vehicle con-. guration under hypersonic � ow is essential to quantify the heat-shieldingrequirement for the thermal protectionsystem (TPS) of space missions. Typically low-lift and high-drag bodies such as large-angle blunt cones are used as heat shields in modern aeroassisted orbital transfer vehicles1 (AOTVs). The development of these space vehicles requires a large volume of heat transfer data, which can also be used to validate computational uid dynamic codes. Although most of the AOTVs operate at very high velocities and high altitudes, the maximum convective heating will occur at conditions corresponding to continuum/near-continuum ow.2 Hence, carefullydesignedground-basedexperimentsin typicalhigh enthalpy continuum ow conditions will be very useful in designing the requisite TPS for such space missions. Previously, many authors have reported heat transfer measurements over large-angle blunt bodies.

The power generation in a gasdynamic laser (GDL) has been theoretically studied. Quasi-one-dimensional unsteady flow equations are numerically solved simultaneously with the rate equation for the laser intensity inside the laser cavity. Steady-state coupled solutions for the field variables and the laser intensity inside the GDL cavity are obtained by a time-dependent numerical technique. The laser intensity variations along the axis of the flow (across the laser cavity) are computed for different laser gas mixture compositions and reservoir conditions. The analysis predicts a sharp spike in the laser intensity at the leading edge of the laser cavity followed by a sharp fall from which it recovers to a uniform constant value for the lower $H_20$ concentrations. It is shown that the $H_20$ concentration above 2% in the $CO_2-N_2-H_20$ gas mixture is detrimental to he power generation.

A theoretical analysis of a downstream-mixing 16-µm CO2 gasdynamic laser revealed the possibility of utilizing the downstream-mixing scheme for the generation of 9.4-µm radiation using a CO2 gasdynamic laser. The flow-field has been analyzed using complete two-dimensional, unsteady laminar form of Navier-Stokes equations coupled with the finite rate vibrational kinetic equations. The analysis showed that integrated small-signal gain of 11.5m−1 for Lorentzian broadening and 4.8m−1 considering Voigt function can be obtained for N2 reservoir temperature of 2000°K and velocity ratio 1:1 between the CO2 and N2 mixing streams. These results (presented in graphs) clearly highlight the large potential of downstream-mixing CO2 gasdynamic laser for 9.4-µm laser generation.

Nonequilibrium nozzle flows of pure gases is common in many aerospace applications such as rocket nozzles, and hypersonic simulation facilities such as wind-tunnel/shock-tunnel nozzles. The basic problems, including the problem of obtaining numerical solutions for nozzle flows with vibrational energy relaxation, have been studied by several authors. With the advent of metallized propellants for solid rocket motors, the nozzle flow consists not only of pure gases. The metallized propellant burnt in the combustion chamber becomes metal oxide particles and are dragged out of the combustion chamber by the nozzle expansion process of the gas. Arc-heated test gas in hypersonic wind tunnels also contains large numbers of particles flowing with the gas. It is a known fact from earlier studies that the presence of particles in the flow can modify the flow expansion process. The effects of such particles on the internal energy nonequilibrium phenomena during the nozzle expansion process is studied in this investigation.

The generation of a 16 μm laser beam through cascading in a downstream‐mixing CO2 gasdynamic laser is studied. To simulate actual lasing action, a generalized, two‐dimensional, flow‐radiation‐coupled power extraction model for a gasdynamic laser is used. Also, to model the cascade process a new four‐mode CO2‐N2 vibrational kinetic model has been proposed. The steady‐state intensity obtained for an exclusive 9.4 μm transition is of the order of 5×107 W/m2. In the cascade mode of operation the steady‐state intensities for 9.4 and 16 μm transitions of the order of 5×107 W/m2 and 1.0×106 W/m2, respectively, have been obtained.

Our data (Reddy et al., Radiat. Res. 141, 252-258, 1995) on the kinetics of the repair of potentially lethal damage in log-phase Chinese hamster V79 cells are used to test some predictions which arise from the different assumptions of the repair-misrepair (RMR) (C. A. Tobias, Radiat. Res. 104, S77-S95, 1985), lethal-potentially lethal (LPL) (S. B. Curtis, Radiat. Res. 106, 252-270, 1986) and double-strand break (DSB) (J. Y. Ostashevsky, Radiat. Res. 118, 437-466, 1989) models. The LPL model defines the time available for repair of PLD (t(rep)) as the time taken to reach maximal survival in a delayed-plating recovery experiment. Those data show that after this time has elapsed, contrary to the expectation of the LPL model, survival can be increased by changing the medium used for delayed plating from fresh growth medium to conditioned medium. According to the RMR model, all potentially lethal lesions should also be committed by that time and be unavailable for repair in the new medium. Only the DSB model correctly predicted that PLD (= DSBs) would still be available for repair after that time. Second, data for split-dose recovery are used to predict the first-order kinetics time constant for DSB repair (tau(DSBR)) using the DSB model (24 +/- 1.5 min). This value is nearly identical to the value of 27 +/- 1 min determined from the data obtained by Cheong et al. using pulsed-field gel electrophoresis (PFGE) (Mutat. Res. 274, 111-122, 1992). The value based on PFGE is used to calculate the value of t(rep) predicted by the DSB model (2.6 +/- 0.1 h), which agrees with the value determined experimentally as the time when changing the delayed-plating medium from growth medium to conditioned medium no longer gives the full recovery seen with delayed plating in conditioned medium (2.5 h). However, some recovery was seen for a change in the medium (growth medium to conditioned medium) up to 5-6 h postirradiation. Reanalysis of the original data on DSB repair shows that they are consistent with two first-order repair rates (18 +/- 7 min and about 52 min). These results are consistent with two pools of DSBs (or cells), each with their own t(rep). The early t(rep), associated with tau(fast), is predicted to be 1.7 +/- 0.7 h, and the late t(rep), associated with tau(slow), is predicted to be about 5 h. Both values are in excellent agreement with the times at which changing from growth medium to conditioned medium no longer gives the full recovery seen in conditioned medium only (the early t(rep)), and the time when changing from growth medium to conditioned medium produces no further increase in survival (the late t(rep)), respectively. It is noted that attempts to correlate radiosensitivity with the rates of DSB repair, rather than using an explicit model such as the DSB model, are unlikely to be productive since survival depends on both tau(DSBR) and t(rep) (as defined in the DSB model) and the latter may be the more important determinant of radiosensitivity (as it appears to be for ataxia telangiectasia cells compared to normal fibroblasts and for irs compared to V79 cells).

The kinetics of the repair and fixation of potentially lethal damage (PLD) was studied in log-phase Chinese hamster V79 cells. The postirradiation (10 Gy) survival of cells treated with hypertonic saline increased when these cells were incubated further in conditioned medium but not in growth medium, indicating that damage which is neither fixed by hypertonic saline nor amenable to repair in growth medium is nonetheless repaired in conditioned medium. Recovery of X-irradiated cells incubated in growth medium or in conditioned medium was maximal by about 70 min and was two times higher in conditioned medium than in growth medium. Cells incubated in growth medium for 70-120 min postirradiation continued to repair damage when subsequently shifted to conditioned medium and attained the same survival as that of cells in conditioned medium only. Thus PLD is not fixed by the time the recovery plateau has been attained in growth medium, and this unfixed PLD can still be repaired when cells are shifted to conditioned medium. To study the kinetics of fixation of PLD (without hypertonic saline), the survival of cells incubated in growth medium for up to 9 h postirradiation was compared with that for cells incubated in growth medium for different times followed by incubation in conditioned medium. These results show that the damage was neither fixed nor misrepaired in growth medium but rather remained unrepaired for up to 2 h, and that damage fixation in growth medium does not begin until after 2 h and is completed by 6 h postirradiation.

While a cell-to-cell contact effect has been reported for a Chinese hamster subline V79-171B, this was not observed for another subline V79 171-S. Therefore, we tested whether the cell-to-cell contact effect on cell survival depended on the cell line or the experimental conditions used. We have cultured and compared both sublines under identical conditions. Both sublines, cultured in Eagle's minimal essential medium (MEM) with 15% serum, had nearly identical cell doubling times and radiosensitivities. For both sublines, the survival of spheroid and monolayer cells subcultured immediately after irradiation were nearly the same, i.e., a radio-protective contact effect for spheroid cells was absent. Under conditions favorable for the repair of radiation induced damage, cell survival was higher for cells in monolayers than for cells in spheroids. Potentially lethal damage (PLD) repair and sublethal damage (SLD) repair were present in both sublines. However, the magnitude of expression of PLD by hypertonic saline was higher for monolayer than for spheroid cells. We conclude that: 1) the reported differences between V79 sublines (contact effect on survival) appear to be dependent on differences between experimental conditions rather than on cell type; 2) delayed plating technique does not detect PLD repair in round spheroid cells; and 3) detection of repair by split dose is independent of cell shape and/or two- or three-dimensional culture conditions.

An attempt is made to obtain similar solutions for gas-particle nonequillibrium nozzle flows. Modified defitions for speed for sound and Mach number are proposed for this study. The governing equations are transformed into a similar form and a single correlating parameter is obtained. The limiting (equillibrium and frozen) speeds of sound are shown to be derivable from the modified definition. The numerical results transpire several interesting phenomena occurring in the nozzle. For example, the approach to isothermal condition of the flow at very large loading ratio is proved with no assumption regarding the lag of the particles. By varying the numerical values of the general correlating parameter, the complete nonequillibrium regime of the flow can be scanned. With the present similar solutions, the flow quantities in a nozzle can be readily determined for different particle sizes, loading ratios, reservoir conditions, and for a family of nozzle shapes without resorting to complex computer programs.

Analysis of gas-particle nozzle flows is carried out with attention to the effect of dust particles on the vibrational relaxation phenomena and consequent effect on the lasing performance of a gas mixture. The relaxation of the particBles during the nozzle expansion process is taken into account simultaneously. The governing equations of the two-phase nozzle flow have been transformed into similar form and general correlating parameters have been obtained. It is shown from the present analysis that the size and the loading ratio of particles in the mixture are the two important controlling parameters in optimizing the lasing performance. The effect of the particles on the optimum performance of a two-phase flow gasdynamic laser is insignificant for smaller loading ratios and for particles of large size. However, the effect is observed to be adverse when the particles of smaller size are involved or when the loading ratio is high. 24 refs.

Nutrient concentration in the growth medium and trypsin affect cellular radiosensitivity in a manner that is related to cell shape (Reddy, Stevenson, and Lange, Int. J. Radiat. Biol. 55, 105-117 (1989); Reddy and Lange, Radiat. Res. 119, 338-347 (1989]. Hence we hypothesized that the concentration of serum in the medium could influence the X-ray sensitivity of cells and that the spread cells in monolayers and round cells in spheroids may differ in their response to the radiosensitizing effect of trypsin. We compared the X-ray sensitivity of monolayer and spheroid cells grown for 19 +/- 1 h in MEM supplemented with 5 or 15% serum. Cells were trypsinized and plated either immediately before, or 2.5 +/- 0.5 h after, irradiation and incubation for repair in situ. Survival of cells in monolayers and in spheroids was higher in MEM with 5% serum than with 15% serum. Trypsin treatment affected the shape and radiosensitivity of cells in monolayers but not in spheroids. When all cells were grown in the same serum concentration and a 2.5-h postirradiation incubation was allowed prior to trypsinization, the X-ray sensitivity of cells in spheroids was greater than that of cells in monolayers. The survival of cells in spheroids became equal to that of monolayer cells when cells in spheroids were converted to monolayers by placing them in 25-cm2 flasks and allowing them 3 h to attach and spread. Cell cycle distributions were nearly the same in monolayers and spheroids cultured in MEM with 5 or 15% serum. We conclude that: (1) serum concentration in the growth medium and trypsin do appear to contribute to the differences in the radiosensitivity of spheroids and monolayer V79 cells; (2) these differences are associated with changes in cell morphology.

A generalized two‐dimensional flow‐radiation coupled model to extract power from a gasdynamic laser is proposed. The model is used for the study of power extraction from a 9.4‐μm CO2 downstream‐mixing gasdynamic laser, where a cold CO2+H2 stream is mixed with a vibrationally excited N2 stream at the nozzle exits. This model is developed by coupling radiation with the two‐dimensional, unsteady, laminar and viscous flow modeling needed for such systems. The analysis showed that the steady‐state value of 9.4‐μm intensity as high as 5×107 W/m2 can be obtained from the system studied. The role of H2 relaxant in the power extraction process has also been investigated.

The aim of this study is to determine whether the repair process in log-phase Chinese hamster V79 cells exposed to X rays is unsaturated, saturable, or saturated. The kinetics of recovery from damage induced by 2 to 14 Gy of 250 kVp X rays was studied by treating cells with 0.5 M hypertonic saline for 20 min at different postirradiation repair intervals. From the kinetic data, the repair half-time (t1/2), the repair time (time needed to attain maximal survival), and the recovery ratio were calculated. The results show that the t1/2 (1.42 min/Gy) and the repair time (6.04 min/Gy) increase linearly with dose, the logarithm of the recovery ratio increases linear-quadratically with dose, and the D0 increases linearly with repair interval at a rate of 2.4 cGy/min. From these results we suggest a model: the repair of damage (undefined lesions) necessary for cell survival is effected by a repair process (t 1/2 of 1.42 min/Gy) which is saturated at doses as low as 2.4 cGy; repair saturation leads to a dose-dependent accumulation of repairable lesions; and interaction among accumulated repairable lesions results in the induction of irreparable (lethal) lesions. We call this the accumulation-interaction model of cell killing by low-LET radiation.

In nonequilibrium gas‐particle nozzle flows, new definitions for effective nozzle area ratio and effective, Mach number, which can be called as virtual area and virtual Mach number, are proposed. By using the definition of virtual area it is shown that the governing equations for the two‐phase nonequilibrium nozzle flow can be effectively reduced to pure type equations. This ‘‘pseudo pure gas’’ resembles that of real diatomic gas with vibrational mode relaxation. By combining the transformed mass and momentum conservation equations and by using the definition of virtual Mach number, simple area‐Mach number relations which are very similar to those of pure gas case have also been obtained.

Based on a method proposed by Reddy and Shanmugasundaram, similar solutions have been obtained for the steady inviscid quasi‐one‐dimensional nonreacting flow in the supersonic nozzle of CO2–N2–H2O and CO2–N2–He gasdynamic laser systems. Instead of using the correlations of a nonsimilar function NS for pure N2 gas, as is done in previous publications, the NS correlations are computed here for the actual gas mixtures used in the gasdynamic lasers. Optimum small‐signal optical gain and the corresponding optimum values of the operating parameters like reservoir pressure and temperature and nozzle area ratio are computed using these correlations. The present results are compared with the previous results and the main differences are discussed.

The influence of Lorentz and Doppler line‐broadening mechanisms on the small‐signal optical gain of lasers and, in particular, gasdynamic lasers, is discussed. A relationship between the critical parameter reflecting the line‐broadening mechanisms and some of the important parameters arising out of the gain optimization studies in CO2‐N2 gasdynamic lasers is established. Using this relationship, methods by which the deleterious effect of the Doppler mechanisms on small‐signal gain can be suppressed are suggested.

The governing equations for gas flows in 16-^m CO2-N2-H2 gasdynamic lasers using conical or hyperbolic nozzles have been presented in universal form so that for a given gas composition the solutions depend on a single parameter that combines all other parameters of the laser system. The solutions of these equations are used to compute the optimum values of small signal optical gain, and the corresponding optimum values of the area ratio, the reservoir temperature T'0 and the binary scaling parameter p'0L', which is a product of reservoir pressure p'0 and nozzle shape factor L', for a wide range of gas mixture compositions. The results are presented in graph form. An optimum value of 2.06% cm'1 gain has been calculated for the gas composition of C02:N2:H2 = 15:65:20.

The design, development and calibration of a shock tube/tunnel is described in this paper. Its main features are: (1) test section size: 30 cm dia jet enclosed in a 30 cm × 30 cm square test section; (2) diameter and overall length of shock tube: 50 mm and 5.63 m respectively; (3) test section Mach number range: 4 to 13; (4) stagnation temperature simulation: upto 8000°K. This facility has been operated in a ‘straight-through’ as well as ‘reflected’ mode. Instrumentation like piezo-electric pressure gauges, thin film heat transfer gauges along with electric analogue net works have been used extensively to calibrate the facility as well as to measure the flow variables inside the shock tube and in the test section. Re-entry heating has also been simulated.

Based on a method presented in detail in a previous work by the authors, similar solutions have been obtained for the steady inviscid quasi‐one‐dimensional nonreacting flow in the supersonic nozzle of a CO2–N2 gasdynamic laser system, with either H2O or He as the catalyst. It has been demonstrated how these solutions could be used to optimize the small‐signal gain coefficient on a specified vibrational‐rotational transition. Results presented for a wide range of mixture compositions include optimum values for the small‐signal gain, area ratio, reservoir temperature, and a binary scaling parameter, which is the product of reservoir pressure and nozzle shape factor.

A review with 18 refs. A comprehensive theoretical analysis of optimization of gain in $CO_2-N_2$ gasdynamic laser employing wedge or conical or hyperbolic nozzles with either $H_2O$ or He as the catalyst is presented. After a review of previous woprk, the usual governing equations for the steady inviscid quasi-1-dimensional flow in a supersonic nozzle of a gasdynamic laser are used to obtain similar solutions for the various flow quantities, which variables are subsequently used to optimize the small-signal gain on the P(20) line of the $(001) \rightarrow (100)$ transition of $CO_2$ at wavelength $10.6 \mu m$. The corresponding optimum values like reservoir pressure and temperature and nozzle area ratio also have been predicted and presented in the form of graphs. The analysis predicts that employing of 2D- wedge nozzle results in higher gain values and the $CO_2-N_2-H_2O$ gas dynamic laser employing 2D-wedge nozzle is operationally the best laser system for which the optimum value as high as $3.1 m^{-1}$ gain can be obtained.

A theoretical analysis of a 16-\mu m $CO_2-N_2-H_2$ downstream-mixing gasdynamic laser, where a cold $CO_2$, $H_2$ stream is mixed with a vibrationally excited $N_2$ stream, tangentially downstream of the nozzle exit, is presented. The flowfield is analyzed numerically using 2-dimensional, unsteady, laminar, and viscous flow modeling, including the appropriate finite-rate vibrational kinetic equations. The effect of variation of different flowfield parameters on 16-mm small-signal gain is studied, and results are discussed in detail. The anal. shows that the presence of $H_2$ gas is detrimental to small-signal gain. The velocity ratio 1:1 between the $CO_2$, $H_2$, and $N_2$ mixing streams is the best choice rendering local small-signal gain as high as 21.75 $m^-1$ and corresponding av. small-signal gain of 16.7 $m^-1$ for $N_2$ reservoir temp. of 2000 K. These high values of small-signal gain clearly underscore the high potential which a downstream-mixing scheme has over the conventional methods for a 16-\mu m laser source.

An analytical method has been proposed to optimise the small-signaloptical gain of CO2-N2 gasdynamic lasers (gdl) employing two-dimensional (2D) wedge nozzles. Following our earlier work the equations governing the steady, inviscid, quasi-one-dimensional flow in the wedge nozzle of thegdl are reduced to a universal form so that their solutions depend on a single unifying parameter. These equations are solved numerically to obtain similar solutions for the various flow quantities, which variables are subsequently used to optimize the small-signal-gain. The corresponding optimum values like reservoir pressure and temperature and 2D nozzle area ratio also have been predicted and graphed for a wide range of laser gas compositions, with either H2O or He as the catalyst. A large number of graphs are presented which may be used to obtain the optimum values of small signal gain for a wide range of laser compositions without further computations.

On utilise un systeme d'equilibrage de force a accelerometre pour mesurer la portance, la trainee et les coefficients de quantite de mouvement. Comparaison avec des resultats theoriques

A 16-µm CO2-N2 downstream-mixing gasdynamic laser, where a cold CO2 stream is mixed with a vibrationally excited N2 stream at the exit of the nozzle, is studied theoretically. The flow field is analyzed using a two-dimensional, unsteady, laminar and viscous flow model including appropriate finite-rate vibrational kinetic equations. The analysis showed that local small-signal gain up to 21.75 m−1 can be obtained for a N2 reservoir temperature of 2000 K and a velocity ratio of 1:1 between the CO2 and N2 mixing streams. Applied Physics Letters is copyrighted by The American Institute of Physics.

Reynolds number, viscosity and atom concentration in hypervelocity nozzles measured using stagnation point heat transfer

We tested our hypothesis that the lower survival of X-irradiated cells in growth medium (GM) relative to that in conditioned medium (CM) is due to differences in nutrient concentration levels rather than to differential effects on cell progression and growth. Chinese hamster V79 cells in log and unfed plateau phase, grown in Eagle's minimal essential medium (MEM) with 15% serum (100% GM), were irradiated. Before plating, cells were incubated in situ in various concentrations of MEM with serum (GM, normal cell progression) or MEM without serum or in CM (no cell progression). Cell survival was the lowest in 100% MEM with or without serum and increased with the decrease in MEM and serum concentrations, reaching a plateau in 40% MEM or 40% growth medium (40% MEM with 6% serum), similar to that in conditioned medium. Growth kinetics was the same in 40 and 100% growth medium, but the D0 of cells in 40% growth medium was higher than that of cells in 100% GM. Similarly, the D0 of cells in 40% MEM was higher than that of cells in 100% MEM, although cell progression was absent in both media. The radiation sensitivity of cells was the same in 40% GM with progression and in 40% MEM and CM with no progression. Cells in low-nutrient media were flatter than those in 100% MEM or GM. There was a correlation between the nutrient concentration in the medium postirradiation and the D0. This correlation was independent of the presence or absence of serum and thus independent of cell cycle progression. The cell morphology which is dependent on the nutrient concentration appears to influence the ability of a fraction of cells to repair their radiation damage.

The purpose of this study was to determine the correlation, if any, between the status of the somatosensory evoked potential (SEP) and functional change in the right upper extremity of patients with right hemiplegia following stroke. Sixty-eight such patients were admitted to a rehabilitation hospital for intensive treatment from 3 to 8 weeks after onset. All had SEP studies by stimulation of the median nerves of the upper extremities and had complete medical, neurologic and functional evaluations. Forty-two patients had an absent SEP; of these only one showed some functional gain in the right upper extremity (RUE) at discharge. Of 14 patients having diminished SEP, 5 (36%) had some functional gain in RUE at discharge. Of 8 having normal SEP, 3 (38%) showed some functional gain on discharge. None of these 64 patients had any function in RUE on admission. Four patients had a normal SEP and some function on admission, with an increase of function on discharge. Of right hemiplegic patients who showed absence of SEP and nonfunction of RUE on admission, 98% gained no functional return in RUE during hospitalization. These data suggest that SEP studies in stroke patients offer useful information for prognosis and rehabilitation programming.

The cidal effect of copper sulphate on pulmonate snail host Lymnaea luteola was studied in relation to lipid metabolism. Alterations in the levels of glycerol, phospholipids, glycerides, sterols, sterol esters and free fatty acids due to copper sulphate treatment are recorded in foot, mantle and digestive gland of this mollusc. These results have been interpreted as part of a mechanism of detoxification, prevalent in this fresh water mollusc.