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Notes: The gain characteristics of a 1.5 μm split contact nonlinear laser amplifier are reported. With an input power of −51 dBm or greater, a nonlinear transfer function was observed with a maximum gain of 26 dB. The maximum pulse repetition frequency for nonlinear gain was 700 MHz.

Notes: Pentacene and tetracene show readily observable photoconductivity when illuminated with light in the blue part of the visible spectrum. We measured the change of photoconductivity with hydrostatic pressure in single-crystal samples of both materials. Possible mechanisms for the observed increase in photoconductivity with pressure are discussed. We conclude that a carrier-mobility increase under pressure is most likely to cause the increase in photoconductivity in the case of pentacene. For tetracene, changes in the absorption spectrum in the range of the excitation wavelengths may also be significant. We also observe a phase transition near 0.3 GPa in tetracene, in agreement with previous results. © 2001 American Institute of Physics.

Notes: Amyloid β-peptide (Aβ) is the main component of senile plaques which characterize Alzheimer's disease and may induce neuronal death through mechanisms which include oxidative stress. To date, the signalling pathways linking oxidant stress, a component of several neurodegenerative diseases, to cell death in the CNS are poorly understood. Melastatin-like transient receptor potential 2 (TRPM2) is a Ca2+-permeant non-selective cation channel, which responds to increases in oxidative stress levels in the cell and is activated by oxidants such as hydrogen peroxide. We demonstrate here that Aβ and hydrogen peroxide both induce death in cultured rat striatal cells which express TRPM2 endogenously. Transfection with a splice variant that acts as a dominant negative blocker of TRPM2 function (TRPM2-S) inhibited both hydrogen peroxide- and Aβ-induced increases in intracellular-free Ca2+ and cell death. Functional inhibition of TRPM2 activation by the poly(ADP-ribose)polymerase inhibitor SB-750139, a modulator of intracellular pathways activating TRPM2, attenuated hydrogen peroxide- and Aβ-induced cell death. Furthermore, a small interfering RNA which targets TRPM2, reduced TRPM2 mRNA levels and the toxicity induced by hydrogen peroxide and Aβ. These data demonstrate that activation of TRPM2, functionally expressed in primary cultures of rat striatum, contributes to Aβ- and oxidative stress-induced striatal cell death.

Notes: Abstract— Mice were infused intravenously for varying periods of time with L-[U-14C]- tyrosine. The specific activity of free tyrosine in the blood and the brain, and of protein-bound tyrosine in the brain, was measured and the mean rate of protein synthesis calculated. The half-life of mixed brain proteins was found to be close to 4 days with infusions lasting 0.5–2 h.The origin of the intracellular tyrosine pool was investigated and it was shown that 60 per cent of this was derived directly from the plasma tyrosine and 40 per cent from protein breakdown within the tissue.

Notes: Secondary Tc cells immune to alphaviruses (BEB, SIN and SFV) cross-react between serologically defined subgroups at the level of target lysis and at the level of induction of response. Despite this apparently complete Tc cell cross-reactivity between BFB, SIN and SFV, amisera raised against BEB and SIN showed virus specificity in their ability to block Tc cell-mediated lysis of alpha virus-infected targets. This result suggests that Tc cells recognize the same viral antigen molecule as antibodies, but with less specificity. Other possible interpretations are discussed.

Notes: Abstract Current designs which involve the use of composite materials in primary aircraft structures are often conservative. This, in turn, significantly lowers the weight advantage that composites have over established metallic airframe materials. Strain restrictions are often applied because the failure mechanism(s) in (fibre) composite joints and stiffener runouts where the stress state is often complex, are not fully understood. Nevertheless, from the airworthiness perspective it is essential that both the static strength and the fatigue behaviour of the components subjected to complex multiaxial stress conditions are both understood and predicted. This topic is extremely complex, and numerous criteria ranging from the purely empirical to the theoretical have been proposed. In both cases, it is necessary to know the localised stress–strain history.One common design methodology is to keep the stresses so low that fatigue will not be an issue. However, this can lead to an overly conservative design. On the other hand, while a detailed (nonlinear) finite element analysis can be performed it is often both resource-intensive and time-consuming. The present paper shows that Glinka's hypothesis can be used in order to calculate the localised stresses and strains for a bonded joint subjected to cyclic loading.This is a new result and has not previously been noted. It has the potential to extend the Hart-Smith design methodology to the adhesively bonded joints in order to encompass durability considerations. This formulation also raises the possibility of enabling the degree of conservatism inherent in traditional joint design to be relaxed provided that failure occurs in the adhesive.This paper also addresses the problem of variable adhesive thickness. We show that while variable adhesive thickness can change the stress and the energy fields, the peak in the strain energy density is relatively insensitive to the stress–strain relationship for the adhesive and that Glinka's hypothesis still appears to be true. This means that, for the present class of problems, even if there is variability in the thickness of the adhesive bond the energy field and, hence, the strength of the joint can be estimated from a purely linear elastic analysis of the joint, provided that failure occurs in the adhesive.

Notes: President Putin's reassertion of state control over more and more of the economy combined with his radical reversal of many of the country's political reforms is ominous. Correcting for some of the political and economic excesses of the original reforms is all to the good, but unless he can do so without sowing the seeds of future recriminations and turmoil, Russia will find it difficult to establish the climate of stable property ownership, encourage long-term investment or spur the diversified economic growth, all of which are essential for political stability and legitimacy.

Notes: 1. The effects of tubocurarine, pancuronium, vecuronium and trimethyl-tubocurarine were examined on the amplitudes of end-plate currents (EPC) produced by repetitive nerve stimulation in cut voltage-clamped fibres of the costocutaneous muscle of the garter snake. The effects of tubocurarine were further studied on the amplitudes of miniature end-plate currents (MEPC) recorded immediately before the trains of nerve stimulation, thus allowing estimates to be made of EPC quantal content.2. All four compounds increased the decline of EPC amplitude with successive impulses (rundown), compared with that observed in control end-plates. There was little effect on the decay time constants of EPC and the effects on rundown were not dependent on membrane potential, indicating that end-plate ion channel blockade was not a major effect in producing rundown.3. In the presence of tubocurarine the quantal content of the EPC in the plateau phase of the trains was reduced when compared with control, indicating a reduction of transmitter mobilization. However tubocurarine had no significant effect on the quantal content of the first EPC of the trains, indicating that the decreased mobilization is not due to an initial effect on transmitter release.4. It is suggested that the prejunctional effect of tubocurarine which results in increased EPC train rundown is primarily on transmitter mobilization. It is also suggested that the actions of tubocurarine and the other neuromuscular blockers tested are mediated through a prejunctional nicotinic receptor which may act as a positive feedback mechanism modulating transmitter mobilization.