Prevalence of IgG antibodies to hepatitis E virus (IgG-anti-HEV) was determined among different animal species from India. Seropositivity varied from 4.4% to 6.9% in cattle, 54.6-74.4% in pigs and 2.1-21.5% in rodents. Of the 44 dogs screened, 10 were positive (22.7%). None of the 250 goat sera tested were found to be anti-HEV positive. Among rodents, over 50% serum samples collected in 1985 from Bandicota bengalensis were positive for anti-HEV antibodies. No evidence of HEV infection was obtained following experimental inoculation of an Indian strain (AKL-90) of HEV into anti-HEV negative pigs and goats. The results document varied prevalence of anti-HEV antibodies in different animal species from India and of inability of Indian pigs and goats to support replication of at least one human strain of HEV.

Our findings suggest that this outbreak of acute encephalitis in Andhra Pradesh was associated with Chandipura virus, adding to the evidence suggesting that this virus should be considered as an important emerging pathogen.

An electron-emitting probe has been used to measure the temporal evolution of the plasma potential V p along a line from target (Ti) to substrate above the racetrack in a high-power impulse magnetron sputtering discharge pulsed at 100 Hz. The 20 ns time-resolution of the probe allowed us to observe the highly dynamic nature of V p as the discharge voltage waveform develops, with large negative V p values (−210 V) and strong potential gradients existing in the magnetic trap region in the first 6 to 8 µs. After 55 to 60 µs, V p is elevated towards ground potential (0 V) and the bulk electric field collapses. Outside the magnetic trap, i.e. on the open field lines, V p reveals much smaller axial and temporal variations, similar to those observed in conventional pulsed dc magnetrons.At standard conditions (Ar pressure of 0.54 Pa and 650 W average power), the results show that for over 50% of the 100 µs plasma 'on-time' the spatial structure of V p provides a large potential barrier for the sputtered post-ionized species so impeding their transport and deposition at the substrate. This barrier is reduced markedly (by 50%) through a small reduction in the magnetic field strength (33% at the target) so increasing the deposition rate by a factor of 6 at a typical position of the substrate (z = 100 mm). The structure of V p is marginally sensitive to changes in pressure (over the range 0.54 to 1.08 Pa), but more strongly dependent on the applied power (over the range 650 to 950 W).

A high temperature stress of 44.5 degrees C for 10 minutes on the larval stages was found to affect the susceptibility of adult Aedes aegypti mosquitoes to chikungunya virus. At this temperature, the mortality of the mosquito larvae was found to be approximately 95%, whereas a temperature greater than 45 degrees C for 10 minutes was found to be lethal. A temperature tolerant (TT) strain was developed by exposing the larvae to a temperature of 44.5 degrees C for 10 minutes at every generation for five generations. This strain was established to determine whether increase in the susceptibility was due to any selection pressure of higher temperature or to the influence of other intrinsic factors such as expression of immunoresponsive (IR) genes. Other studies on these mosquito strains showed that when maintained at 28 +/- 1 degrees C, there was no difference in the larval duration and mortality in the immature stages, but the mean survival of female mosquitoes in the TT strain was 5-6 days longer. Conversely, when mosquitoes were maintained throughout at 37 degrees C the mean survival of the mosquitoes decreased drastically in both strains, but the mean survival of females in the TT strain was 5-6 days longer compared with the unstressed controls. This increases the probability of at least one more blood meal. Fecundity of the TT strain was found to be lower than that of the control mosquitoes. Data suggest that expression of certain IR genes was affected by the heat shock. Some of these genes were up-regulated and down-regulated, which may have affected the susceptibility of mosquitoes to the virus. Although there was some selection in the temperature-tolerant individuals in the TT strain, when stressed by heat they showed expression of IR genes in a pattern similar to that in the normal controls. It appears that an increase in temperature above the average temperature of an area might help increase the proportion of virus-susceptible mosquitoes in the population. Such an increase in temperature in an endemic area would not only enhance the selection of temperature-tolerant individuals in a population having more longevity, but would also affect both intrinsic and extrinsic factors by reducing the extrinsic incubation period and increasing susceptibility of mosquitoes to viruses due to affected expression of IR genes.

Using an emissive probe the spatial-temporal distribution of the plasma potential V p in a high power impulse magnetron sputtering discharge has been measured. The magnetron (with a planar circular titanium target) was operated in argon gas at a fixed pressure of 0.54 Pa, a pulse frequency of 100 Hz with a 100 µs on-time and average power of 650 W. In the early part of the voltage pulse (∼6–8 µs), V p attains deep negative values (∼−150 V) at positions close to the target (10 mm) and above the racetrack, diminishing with distance, but never reaching ground potential, even at excursions of 80 mm. In the confined plasma region, extraordinarily high axial and radial electric field components, up to several kV m−1, are calculated from the plasma potential measurements. As the plasma develops and the discharge current reaches a maximum (at ∼40 µs), V p is elevated everywhere in the plasma, however, still with deep negative values (down to −40 V) at positions closest to the target. From the derived electric fields and modelled (vacuum) magnetic field, the 2D distribution of E × B electron drift velocities has been determined. During the early discharge phase, a broad drift channel is predicted above the racetrack, with drift speeds up to ∼3 × 105 ms−1 centred ∼30 mm above the target racetrack. As the discharge develops, these speeds reduce by about a factor 3 and the centre of the velocity distribution moves further away from the target and inwards towards the discharge axis, resembling that observed in dc and pulsed-dc magnetron operation.

Using an RF-compensated Langmuir probe, plasma parameters have been investigated in a discharge produced by a dual frequency-dual antenna: the next generation of large-area inductively coupled plasma (ICP) sources. The ICP source was made of two concentric spiral copper coils embedded into each other. The inner and outer coils were energized by RF frequencies of 2 and 13.56 MHz, respectively. The discharge was operated at an average pressure of 10 mTorr in an argon gas environment. The probe was positioned at a fixed location of 70 mm from the source and 160 mm from the centre of the ICP source to measure the plasma parameters. However, for discharge uniformity measurements, the probe position was varied from the centre of the discharge to 200 mm towards the edge. It was found that the ion density distribution over the wafer varies with RF power ratio (P 2 MHz /P 13.56 MHz). For a fixed power at 13.56 MHz (P 13.56 MHz), the plasma density increases very slowly with P 2 MHz , when P 2 MHz < 400 W; however, the plasma density increases rapidly when P 2 MHz > 400 W. The electron temperature and plasma potential measurements show decreasing trends with increasing P 2 MHz at constant P 13.56 MHz. The ion density measurements over the substrate show that good discharge uniformity (∼4%) can be achieved by adjusting the RF power ratio (P 2 MHz /P 13.56 MHz).

The marked difference in behaviour between HiPIMS and conventional DC or pulsed-DC magnetron sputtering discharges with changing magnetic field strengths is demonstrated through measurements of deposition rate. To provide a comparison between techniques the same circular magnetron was operated in the three excitation modes at a fixed average power of 680 W and a pressure of 0.54 Pa in the nonreactive sputtering of titanium. The total magnetic field strength B at the cathode surface in the middle of the racetrack was varied from 195 to 380 G. DC and pulsed-DC discharges show the expected behaviour that deposition rates fall with decreasing B (here by ~ 25 to 40%), however the opposite trend is observed in HiPIMS with deposition rates rising by a factor of 2 over the same decrease in B.These observations are understood from the stand point of the different composition and transport processes of the depositing metal flux between the techniques. In HiPIMS, this flux is largely ionic and slow post-ionized sputtered particles are subject to strong back attraction to the target by a retarding plasma potential structure ahead of them. The height of this potential barrier is known to increase with increasing B.From a simple phenomenological model of the sputtered particle fluxes, using the measured deposition rates from the different techniques as inputs, the combined probabilities of ionization, α, and back attraction, β, of the metal species in HiPIMS has been calculated. There is a clear fall in αβ (from 0.9 to 0.7) with decreasing Bfield strengths, we argue primarily due to a weakening of electrostatic ion back attraction, so leading to higher deposition rates. The results indicate that careful design of magnetron field strengths should be considered to optimise HiPIMS deposition rates.

Background: Age dependent susceptibility was observed in Chandipura virus (CHPV) infected mice through intravenous and intraperitoneal route. Adult mice were susceptible only through intracerebral route of infection. Immature neuron and some other biological variables including immature immune system are considered to be important factor for age related susceptibility in some diseases. As Chandipura virus infects both young and adult mice brain through intracerebral route the role of immune system during peripheral infection in young susceptible mice needs to be studied.