The IL-2 receptor complex: expression and function on normal and leukemic B cells

The interleukin 2 receptor (IL-2R) is composed of at least three different chains that may be variably expressed on normal and neoplastic lymphocytes. While considerable knowledge has been gained on the expression of the IL-2R alpha chain on human leukemic cells of different origin, less is known of the beta and gamma chains. In view of the highly pleiotropic functions exerted by IL-2, the IL-2-IL-2R interactions may play an important role in various leukemias. In this review we focus on the expression and function of the IL-2R complex on human normal and leukemic B cells. Possible implications in the expansion of the neoplastic clone and in the clinical course of the disease are discussed.     

Partial biochemical characterization of nitric oxide synthase in the caudal spinal cord of the teleost Oreochromis niloticus

This article presents two cases in which an intraarticular fracture of the ulnar head occurred in association with a dorsal dislocation of the distal radioulnar joint. After open reduction and internal fixation of the osteochondral fragment, final outcomes were excellent.     

Impulse Response of Cross-Phase Modulation Filters in Multi-span Transmission Systems with Dispersion Compensation

As shown by Chianget al.(1996), cross-phase modulation on each channel of a wavelength-division-multiplexed transmission system can be viewed as a phase modulation, where the modulating signal is the sum of the input intensities of all the other copropagating channels, each filtered by a low-pass filter, whose bandwidth decreases with the walk-off parameter. We give an explicit expression of the impulse response of such filter in the general case of dispersion mapped transmission systems. We show by simulation that this filter, in intensity-modulated transmission systems, gives an optimal prediction of the signal phase even when the underlying assumption of negligible envelope distortion upon which its derivation is based is strongly violated. As an application, we show an analytical evaluation of the spectral broadening induced by XPM in multi-span compensated systems.     

Environmental impact from mountainous olive orchards under different soil-management systems (SE Spain)

Soil erosion, runoff and nutrient-loss patterns over a two-year period (1999-2000) were monitored in erosion plots on a mountainside with olive (Olea europaea cv. Picual) trees under three different types of soil management: (1) non-tillage with barley (Hordeum vulgare) strips of 4 m width (BS); (2) conventional tillage (CT); (3) non-tillage without plant strips (NT). The erosion plots, located in Lanjaron (Alpujarras) on the southern flank of the Sierra Nevada Mountains in south-eastern Spain, had 30% slope at an altitude of 565 m and 192 m(2) (24x8 m) in area. The highest erosion and runoff values, ranging from 10.5 to 40.7 t ha(-1) yr(-1) and from 26.5 to 51.5 mm yr(-1), respectively, over the entire study period, were measured under NT. In CT, erosion ranged from 1.0 to 10.4 t ha(-1) yr(-1) and runoff from 6.7 to 15.2 mm yr(-1), while under BS, erosion ranged from 1.7 to 2.4 t ha(-1) yr(-1) and runoff from 19.6 to 20.0 mm yr(-1). It is concluded that the BS and CT reduced the soil erosion by 92% and 78%, with respect to the NT, and the runoff by 49% and 72%, respectively. The total NPK losses (sediments and runoff) from BS averaged 0.87, 0.07 and 0.72 kg ha(-1), from CT 1.82, 0.11 and 0.97 kg ha(-1) and from NT 3.15, 0.29 and 2.45 kg ha(-1), respectively. In addition, nutrient concentrations in the surface runoff were higher than the recommended level for standard water quality for N-NO(3), N-NH(4) and soluble P, particularly from NT and CT. These results support the recommendation of non-tillage with barley strips for sloped agricultural land in order to reduce erosion and pollution.     

Process development of amorphous silicon/crystalline silicon solar cells

We have already investigated some crucial limiting process steps of the amorphous silicon (a-Si)/crystalline silicon (c-Si) solar cell technology and some specific characterization tools of the ultrathin amorphous material used in devices. In this work, we focus our attention particularlyon the technology of the ITO front contact fabrication, that also is used as an antireflective coating. It is pointed out that this layer acts as a barrier layer against the diffusion of metal during the annealing treatments of the front contact grid. The criteria of the selection of the metal to be used to obtain good performance of the grid and the deposition methods best suited to the purpose are shown. We were able to fabricate low temperature heterojunction solar cells based p-type Czochralski silicon, and a conversion efficiency of 14.7% on 3.8 cm² area was obtained without back surface field and texturization.     

Characterization of the electrochemical process responsible for the free radical release in hard metals

WC-Co mixtures, widely used in industry, have been intensively investigated because of their noxious effects on human health when the powder is inhaled. A particular chemical reaction, taking place in the presence of both WC and Co powders has been claimed to contribute to the development of the lung diseases. Activated oxygen species (AOS) are produced through the reduction of oxygen in presence of the WC-Co particles. It has been demonstrated that this spontaneous process involves the oxidation of Co and the reduction of oxygen catalysed by WC via an electrochemical redox reaction, being Co the anode and WC the cathode. The electrolyte for this process, taking place in the distal zone of the lungs, is a wet layer distributed on the powder surface by the humid ambient of the lungs. Being the electrodes short-circuited spontaneously, the Co oxidizes and the oxygen dissolved in the wet layer reduces at a high rate being catalysed by WC. In our investigation, we have focussed our attention to the electrochemical characteristics of the process and pointed out that the spontaneous process may take place at an appreciable rate only when the WC surface is covered by a thin layer of electrolyte, so maximising the diffusion of O₂ through the solution.A voltaic cell corresponding to the overall spontaneous electrochemical process has also been assembled and discharged at constant current. It has been experimentally determined that in the same voltaic cell, during discharge, species are produced which can react with gluthatione (GSH), a component of the antioxidant system protecting cells, in the same way as the AOS produced by the industrial WC-Co mixture.     

Porous silicon in solar cells: A review and a description of its application as an AR coating

In this paper, we first review the potential applications of porous Si in solar cell structures. Then we describe the fabrication of this material by both electrochemical and chemical etching methods, providing some guidelines for a better comprehension of the influence of each process parameter. After that, the properties of porous Si in terms of morphology, structure, photoluminescence, and electroluminescence emissions are summarized together with their actual photovoltaic applications.The results of our study specifically address the creation of an antireflection (AR) coating for polycrystalline Si based solar cells. We have demonstrated the feasibility of a very efficient porous Si AR layer, prepared by a simple, cost effective, chemical etching method. The formation of a porous Si layer about 0.5 μm thick on the polycrystalline wafer results in an effective reflectance coefficient R_eff lower than 5% in the wavelength region from 350 to 1150 nm. The drastic reduction of the optical losses is controllable by the process parameters and is almost independent of the starting substrate.     

New Interfacial Rheology Characteristics Measured Using a Spinning Drop Rheometer at the Optimum Formulation. Part 2. Surfactant–Oil–Water Systems with a High Volume of Middle-Phase Microemulsion

This article is a continuation of our first study on dilational interfacial rheology properties at optimum formulation for surfactant-oil–water systems at low surfactant concentration just above the cμc. Here, we have investigated a high content of middle-phase microemulsion with an optimum WIII phase behavior for a system containing sodium dodecyl sulfate, n-pentanol, and kerosene. A new oscillating spinning drop interfacial rheometer was used to measure the interfacial properties. The very low dilational elasticity moduli and phase angle found at or near hydrophilic–lipophilic deviation (HLD) = 0 are related to the presence of the bicontinuous phase microemulsion and to the fast surfactant exchanges between the bulk and the interface, regardless of the phases involved in the measurement using the spinning drop apparatus, i.e., the two-phase excess oil and excess water (O-W) or the bicontinuous microemulsion and excess water (M-W). We show that at or near optimum formulation, the interfacial tension and the dilational modulus for the M-W case almost instantly reach equilibrium, because of the high surfactant content in the microemulsion and the fast exchanges between the bulk and the interface. In contrast, when both excess phases (O-W) are measured, the changes in these properties are slower, due to the scarce presence of surfactants in both phases. The possibility of having almost all the surfactants trapped in the middle-phase bicontinuous microemulsion could explain the emulsion instability in all the WIII range. This is behaving as if there were no surfactant available in the oil and water phases to stabilize the oil or water droplets thus formed.