Peripheral pain mechanisms

A promising new treatment for glioma involves Auger electron emitters such as 125I or 123I conjugated to deoxyuridine (IUdR). However, the presence in tumour deposits of non-proliferating cells with clonogenic potential poses a major limitation to this cycle-specific therapy. We have used multicellular tumour spheroids derived from the human glioma cell line UVW to study [125I]IUdR-targeted radiotherapy in aggregates containing cells in different proliferative states. Autoradiographic identification of labelled cells indicated that nuclear incorporation of [125I]IUdR decreased markedly with increasing size of spheroid. IUdR incorporation was maximal in the surface layer of cells and decreased with depth within spheroids. Radiopharmaceutical uptake corresponded closely to the regions of cell cycling as indicated by staining for the nuclear antigen Ki67. The uptake of drug was enhanced by increasing the duration of incubation from 52 h to 104 h. These observations suggest that significant sparing of non-cycling malignant cells would result from treatment delivered as a single injection of radiolabelled IUdR. To achieve maximal therapeutic effect. IUdR should be administered by multiple injections, by slow release from biodegradable implants or by slow-pump delivery.     

Iterative demodulation and decoding of turbo-coded M-ary noncoherent orthogonal modulation

This paper considers bit-interleaved coded modulation (BICM) with a turbo channel code and M-ary orthogonal modulation. The BICM signal is iteratively demodulated and decoded in a noncoherent fashion. A soft demodulator suitable for noncoherent orthogonal modulation is presented, and the convergence of the iterative receiver is analyzed through extrinsic information transfer charts. The demodulator can work either with or without fading amplitude estimates. Extensive simulation results are presented for the well-known cdma-2000 turbo code, and the results are compared with the corresponding channel capacities, which are computed using a Monte Carlo technique. The results indicate gains of up to 1 dB relative to noniterative BICM can be achieved with the iterative receiver.     

Transient liquid phase bonding of HfC-based ceramics

Transient liquid phase (TLP) bonding enables joining at lower temperatures than traditional bonding techniques and preserves the potential for high-temperature applications, making it particularly attractive for joining ultra-high-temperature ceramics (UHTCs) such as carbides and borides. The feasibility of a TLP joint between “pure” carbides has been recently demonstrated. The present study examines the interactions that occur between undoped HfC or MoSi₂-doped HfC and a Ni/Nb/Ni multilayer interlayer during TLP bonding. Bonding is performed at 1400 °C for 30 min in a high-vacuum furnace. SEM–EDS characterization shows that the reaction layer formed at the interlayer/ceramic interface contains mixed carbides and depending upon the ceramic, Ni–Nb–Hf, or Ni–Nb–Hf–Si, or Ni–Nb–Si alloys. Nanoindentation tests traversing the reaction layer between the bulk ceramic and Nb foil midplane also show a clear transition zone across which the indentation modulus and hardness vary. Crack-free joints have been obtained with undoped HfC. The addition of 5 vol% MoSi₂ introduces small (<5 μm long) isolated cracks within the reaction layer, whereas with 15 vol% MoSi₂ added, cracking was pervasive within the reaction layer. When the reaction layer exceeds a critical thickness, as in the case of the bond obtained with HfC doped with 15 vol% MoSi₂, residual stresses become sufficiently large to cause extensive cracking and bond failure. The results suggest a need to characterize and balance the positive role of additives on sintering with the potentially deleterious role they may have on joining.     

Persistent organochlorine compounds in fetal and maternal tissues: evaluation of their potential influence on several indicators of fetal growth and health

Some organochlorine compounds, such as polychlorinated biphenyls (PCBs), have a tendency to bioaccumulate in humans and predators at the top of the food chain. We have recently confirmed the transplacental transfer of these compounds and the present study has been designed on the same material with the aim of investigating their potential health effects on newborns from 70 pregnant women, resident in a Northern Italy industrial town. Organochlorine compounds [namely, p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT), p,p′-dichlorodiphenyldichloroethene (p,p′-DDE), hexachlorobenzene (HCB), and PCBs] have been analyzed both in cord and maternal serum, placenta, and maternal subcutaneous adipose tissue by GC-MSD. p,p′-DDT levels in the adipose tissue resulted significantly (p < 0.05) related to birth length. Mothers of neonates born by preterm programmed caesarean delivery showed significantly (p < 0.005 for both) higher serum p,p′-DDE serum concentrations and p,p′-DDT levels in the adipose tissue, as compared to mothers delivering at term.     

An Abstract Decision Procedure for Satisfiability in the Theory of Recursive Data Types

The theory of recursive data types is a valuable modeling tool for software verification. In the past, decision procedures have been proposed for both the full theory and its universal fragment. However, previous work has been limited in various ways. In this paper, we present a general algorithm for the universal fragment. The algorithm is presented declaratively as a set of abstract rules which are terminating, sound, and complete. We show how other algorithms can be realized as strategies within our general framework. Finally, we propose a new strategy and give experimental results showing that it performs well in practice.     

Solar-blind UV photodetectors for large area applications

In this paper, we extensively investigate a family of solar-blind thin-film photodetectors optimized for the ultraviolet spectrum (UV). The devices are p-i-n structures made of hydrogenated amorphous silicon (a-Si:H) and silicon carbide (a-SiC:H) on a glass substrate. At room temperature the photodetectors exhibit values of quantum efficiency of 20% at λ=187 nm, and are transparent to visible radiation. The excellent sensitivity of the device at short wavelengths is explained within the framework of a diffusive model of transport, taking into account the effects of hot carrier relaxation. The rejection of visible light is obtained with an appropriate design of the energy gap and intrinsic layer thickness. The great advantage of this technology lies in the possibility to produce low-cost, large-area arrays of photodetectors