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This paper analyses the field performance of different off-grid generation technologies applied to the electrification of rural villages. Autonomous diesel generators are the most extended technology. It is a well known application, although it has also some disadvantages: fuel transportation and consumption costs, maintenance needs or environmental problems. In places where accessibility is difficult and costly, the use of local energy resources (basically renewable) constitutes a significant advantage. Due to the intermittent character of those resources, renewable generation systems are sometimes associated to diesel gen-sets in order to increase the reliability of supply of small and medium-size communities. A comparative analysis between diesel, hydro-diesel and photovoltaic-diesel technologies is presented in this article. It is based on data collected from systems installed in the rural area of the province of Jujuy, northwest of Argentina. The study covers from year 2001 to 2008, with a research universe of 16 locations supplied by thermal diesel generation (1 with a large-diesel system and other 15 with smaller ones), 5 locations with hydro-diesel and 7 with photovoltaic-diesel systems. The energy demand evolution of rural villages is also studied because of its influence on the system operation and sustainability.

Refugee survivors of torture in the United Kingdom have multiple problems, of which pain may be underrecognized, given the high prevalence recorded in similar populations in Denmark.To establish in a UK sample the prevalence of persistent pain and to investigate associations between specific pains and torture methods.A cohort of a random 20% sample attending a specialist UK center for survivors of torture in 2005 was taken. All complaints of pain recorded at initial interview were categorized for body site and putative pain mechanism. These were compared with the database of personal variables and data on torture using odds ratios (ORs) and exact probability.Of 115 men and 63 women, with mean age of 30 years, 78% reported persistent multiple pains, mainly in the head and low back. They had experienced a median of six torture methods. There was a clear association between female abdominal/pelvic/genital pain and rape/sexual assault (17 of 34 vs. zero of 17: exact P0.001) and between male anal pain and rape (two of nine vs. two of 77: OR=6.00; 95% confidence interval=1.79-20). Tests of foot/leg pain with falaka and shoulder pain with suspension did not show expected associations.A significant relationship emerged between torture and report of persistent pain at a high prevalence. Findings do not support the widespread clinical assumption that complaint of persistent pain after torture is predominantly a manifestation of psychological distress. Rather, complaints of pain in torture survivors should be assessed and treated in relation to physical trauma.

We present the electrical and structural characterization of Al x Ga 1− x As layers grown in a metallic-arsenic-based-MOCVD system. The gallium and aluminium precursors were the metal-organic compounds trimethylgallium (TMGa) and trimethylaluminium (TMAl), respectively. Al x Ga 1− x As layers that were grown at temperatures less than 750 °C present a high electrical resistivity. Independent of the used III/V ratio the samples that were grown at temperatures greater that 750 °C were n -type with an electron concentration of around 10 17 cm −3 and a carrier mobility of 2200 cm 2 /V-s. Chemical composition studies by SIMS exhibit the presence of silicon, carbon and oxygen as the main residual impurities. Silicon concentration of around of 10 17 cm −3 is very close to the free carrier concentration determined by the Hall-van der Pauw measurements. Composition homogeneity and structural quality are demonstrated by Raman measurements. As the growth temperature is increased the layers compensation decreases but the Raman spectra show that the crystalline quality of the layers diminishes.

Ohmic contacts with a palladium (Pd) diffusion barrier were formed on GaAs substrates. The metal-contact structure consists of a gold-based-alloy/Pd/semiconductor-substrate. Characteristics of the deposited Pd films by “electroless” deposition on semiconductor-substrates are reported. SIMS analysis realized on the metal-semiconductor structures demonstrates the capability of the Pd films to act as a diffusion barrier. Contact resistance of the ohmic contacts was measured by the transmission line method (TLM).

High penetration (HP) Wind Diesel Hybrid Systems (WDHS) have three modes of operation: Diesel Only (DO), Wind Diesel (WD) and Wind Only (WO). The HP-WDHS presented in this article consists of a Wind Turbine Generator (WTG), a Diesel Generator (DG), the consumer Load, a Ni–Cd Battery based Energy Storage System (BESS), a discrete Dump Load (DL) and a Distributed Control System (DCS). The DG includes a friction clutch which allows the Diesel Engine (DE) to be engaged (DO and WD modes)/disengaged (WO mode) to the Synchronous Machine (SM). The DCS consists of a sensor node which measures the SM speed and active power, calculates the reference active power PREF necessary to balance the active power in the WDHS and communicates this PREF value through a message to the BESS and DL actuator nodes. In the WD mode both the DG and WTG supply active power to the system and the DE speed governor regulates the system frequency. However in an HP-WDHS the power produced by the WTG (PT) can be greater than the one consumed by the load (PL). This situation means a negative power in the DG (power inversion) with its speed governor unable to regulate frequency. To avoid this situation, the DCS must order coordinated power consumption to the BESS and DL in order to keep the DG produced power positive. In this article it is shown by simulation how the DCS manages both a temporary power inversion and a permanent one with the mandatory transition from WD to WO mode. The presented graphs for frequency, voltage, active powers of the system elements and battery voltage/current show the effectiveness of the designed control.

Research published on bioreactors discusses the importance of integrating reactor kinetics and mixing as the basis for understanding process hydrodynamics and developing sound design procedures. Nonetheless, many studies are focused on either kinetics or mixing, but studies on the integration of both are seldom found in the literature. Despite the availability of several mixing models (e.g., completely stirred tank reactor, plug flow, dispersion model, completely mixed tanks in series model, and the compartments model), there is an intrinsic complexity in studying process kinetics and reactor hydrodynamics experimentally. In this sense, this work reports the results of a 6-month study for three pilot-scale anaerobic ponds (APs); of which, two had modified physical configurations (one with a mixing chamber, the other with horizontal baffles) and the third was a conventional AP run as a control unit. They were evaluated under three different hydraulic loading rates. The AP provided with the mixing ...

The photoluminescence (PL) of nonconjugated and bioconjugated core-shell CdSe/ZnS quantum dots (QDs) has been discussed in this paper. Commercial CdSe/ZnS QDs with the size of 3.6-4.0 nm covered by polymer with emission at 560-565 nm (2.19-2.22 eV) have been used. The QD bioconjugation is performed with the mouse anti PSA (Prostate-Specific Antigen) antibody (mab). PL spectra of nonconjugated QDs are characterized by a superposition of PL bands related to exciton emission in the CdSe core (2.19-2.22 eV) and to hot electron-hole emission via surface states (2.37, 2.73 and 3.06 eV) at the CdSe/ZnS or ZnS/polymer interfaces. The PL spectrum of bioconjugated QDs has changed dramatically, with essential decreasing of the hot electron-hole recombination flow via interface states. This effect is explained on the base of re-charging of QD interface states at the bioconjugation. It is shown that the CdSe/ZnS QDs with interface states are very promising for the study of bioconjugation effects to antibodies (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Combining the sol gel method and spin coating technique, yttrium iron garnet (YIG) films were obtained on silicon (Si) substrate. Four YIG films with different thicknesses were fabricated to achieve low FMR linewidth. The x-ray diffraction has shown a single phase, belonging to the cubic structure of the YIG, while the morphology of the films has presented small pores and some grains on the surface. The FMR linewidth of the YIG films decreased 110 Oe, 108 Oe, 93 Oe and 71 Oe as the film thickness increased 134 nm, 246 nm, 376 nm and 489 nm, respectively. This result indicates that high-quality YIG films can be achieved on Si substrates, controlling the thickness. The sol gel method is shown as a very economical and easy alternative to obtain YIG films with low FMR linewidth, which may be important for making microwave integrated devices.

It is not easy, in general, to improve the mechanical properties of aluminium alloys by traditional nitriding methods. By contrast, plasma immersion ion implantation (PIII) has been successfully used for hardening and in wear resistance improvement. The present work sets out to investigate the formation of AlN on 6061T6 aluminium samples by the PIII process at low energy (2–6 keV) with ion doses in the order of 1018 ions/cm2 and from nitrogen–argon mixtures at different concentrations (N70–Ar30, N50–Ar50 and N30–Ar70) maintained at ∼400 °C sample temperatures. The outcome was evaluated by X-ray diffractometry, scanning electron microscopy, Vickers microhardness tests and profilometry.

Hybrid materials from TEOS–TBOT–PDMS have been prepared and pyrolyzed between 400 and 1,000 °C. The surface characteristics of this type of materials have been studied by nitrogen adsorption, mercury intrusion porosimetry, and inverse gas chromatography at infinite dilution (IGC). IGC has been used for obtaining the dispersive and acid–base surface energies of the different materials. The specific surface areas and pore volumes of the studied samples have resulted to increase the pyrolysis temperatures ranging between 400 and 600 °C and decrease for higher temperatures. On the other hand, surface energies increase when the materials are pyrolyzed between 400 and 800 °C and then decrease after pyrolysis at 1,000 °C. When the material is pyrolyzed at the highest temperature, the surface energies are close to that of typical glasses. It has been observed that pyrolyzing at 800 °C the material has the highest values of both components of the surface free energy (dispersive and specific). The surface energy–pyrolysis temperature variation does not correspond to the formation of micropores in the material during the pyrolysis process. Therefore, it has been assumed that high energy active sites must be formed on the surface when the materials are pyrolyzed at 800 °C.

Grape pomace is the main by-product from the wine industry. It is principally made up of grape skin and seeds. Drying this by-product is the first step for the later extraction of components with high added value like oil or antioxidants. Due to the different characteristics of the components, the study of the drying kinetics of grape pomace must be addressed taking its components into account one by one. For that purpose, grape seeds from the Spanish wine industry were dehydrated in a convective laboratory dryer at 70 °C and at 1, 2 and 3 m/s until a weight loss of 40% was reached. Drying kinetics was determined in triplicate. Modelling was carried out by means of a diffusion model without considering shrinkage and external resistance. Grape seeds were assumed to be spherical. For all the fits, the explained variance was higher than 96.9 % and the mean relative modulus was lower than 1.7 %. Between 1 and 2 m/s, effective diffusivity increased in line with air velocity, although the values of effective diffusivity calculated for 2 and 3 m/s were similar. It seems to indicate that for the experimental conditions under study, the external resistance is not negligible at 1 and 2 m/s and for higher air velocities the internal resistance to mass transfer controls the drying process. These results coincide with those found by other authors when studying different food products.

Samples of pure titanium have been treated by means a plasma immersed ion implantation (PIII) process in a DC glow discharge in pure oxygen and in different nitrogen-oxygen mixtures. In contrast with conventional voltage supply based glow PIII, the present study has been conducted with a novel specifically designed high current supply which allows a high electron density to be kept constant, regardless of gas pressure variations, within the operational ranks. Thus, the acquired sample characteristics can be more clearly ascribed to the chemical composition of the mixture. One stratified TiO2 (rutile) and TiN0.26 layer was identified from XRD and Raman spectroscopy, both of these compounds reputedly being highly biocompatible. The superficial hardness of the samples was improved up to more than five times that of the untreated reference sample, namely, ∼1600 Vickers microhardness (10 g load) thanks to a 2–6 μm deep implanted layer. These optimal results have been obtained from an 80% nitrogen 20% oxygen mixture at 1×10-2 torr. Furthermore, with this gas proportion, the best roughness finishing of the sample set was accomplished, which can be relevant for biocompatible applications.

EDEMA DE EXTREMIDAD INFERIOR SECUNDARIO A NEUROFIBROMA POPLITEO GIGANTE Resumen Introduccion. El neurofibroma solitario es una lesion benigna que se origina de los nervios. Se presenta en adultos jovenes sin predominio de sexo. La escision es considerada el tratamiento de eleccion. Caso clinico. Mujer de 37 anos, remitida a nuestro servicio por edema en el pie y la pierna derecha de varios meses de evolucion. En la exploracion clinica se aprecia tumoracion solida, rodadera, no adherida a planos profundos, de gran tamano, ocupando la fosa poplitea. La exploracion con eco-Doppler aprecia permeabilidad de arteria y vena popliteas, muy desplazadas de su eje. La angio-RM confirma una formacion quistica en hueco popliteo, de 60 mm × 40 mm. La sintomatologia de la paciente y el riesgo de complicaciones (trombosis venosa, dano a la arteria poplitea por traumatismo cronico) determinaron la indicacion quirurgica. En la intervencion se identifica una tumoracion solida y encapsulada, sin conexion con paquete vascular, pero intimamente dependiente de trayecto nervioso ciatico popliteo externo. Se extirpo en su totalidad. El postoperatorio transcurrio con normalidad. La paciente permanece asintomatica y en las sucesivas revisiones no se ha objetivado recidiva ni complicaciones vasculares. Conclusion. Los neurofibromas son tumores benignos que se localizan en cualquier lugar del organismo y pueden alcanzar gran tamano. Deben ser extirpados quirurgicamente si provocan sintomas o complicaciones (dolor, compresion, deterioro neurologico) y deben ser estudiados ante sospecha de degeneracion maligna. El pronostico tras reseccion quirurgica es bueno y la recurrencia es rara. [ANGIOLOGIA 2009; 61: 359-64]

This work presents the optical and structural characterization of p-type GaAs epilayers. The gallium precursor was the organometallic compound trimethylgallium (TMG). The influence of the doping in the optical and structural properties of the GaAs layers has been studied by photoluminescence (PL) and Raman dispersion measurements. The range of analyzed hole concentration was from 1017 to 1019 cm-3 as measured by the Hall-van der Pauw method. For carrying out doping p-type, it was necessary to modify the hydrogen activity in the growth atmosphere with the control of a H2+N2 mixture, which was used like transporting gas. The photoluminescence response and Raman dispersion of the layers are strongly dependence of the growth temperature, which were investigated based on the hole concentration. The PL response of the layers shows two radiative transitions, band-to-band and band-to-C-acceptor at low hole concentration and disappears at high concentrations. Raman scattering spectra show LO mode at 270 cm-1 for low doped samples and a LO-like mode at 290 cm-1 produced by the phonon-holeplasmon coupling for high doped samples.

Thin polycrystalline ZnO films were grown on silicon substrates by dc reactive magnetron sputtering using zinc oxide targets. The quality of the ZnO layers was assessed by X-ray diffraction (XRD), atomic force microscopy, Raman scattering, and photoluminescence measurements. The XRD studies and Raman studies revealed that the ZnO films crystallize in the wurtzite structure. Room temperature photoluminescence spectra consisted of a narrow near-band-edge ultraviolet band and a broad defect-related green band with peak positions at 380 and 516 nm, respectively. The main goal of the work was to define the growth conditions to prepare zinc oxide films with adequate properties to be used in electroluminescent devices. The films exhibited the best surface appearance with a 40:1 argon/oxygen flow rate, a total pressure of 1.5×10−3 mbar, and a substrate temperature of 230 °C. The structural and luminescence properties improved noticeably with the thermal annealing processes at 800 °C for 1 h.

Hybrid materials have been obtained using a given concentration of tetraethylorthosilicate (TEOS) and polydimethylsiloxane (PDMS). Different size and shape monolithic samples have been achieved by using containers of both different evaporation areas and heights. The hybrid materials have been pyrolyzed under nitrogen atmosphere to yield porous silicon oxycarbide glasses, consisting of interconnected spherical particles and a continuous open-pore channel. The texture of the glasses shows a gradient particle size distribution (PtSD) from the top (2.88 μm) to the bottom (7.83 μm) of the samples. This gradient in the particle size leads also to a gradient distribution of porosities in the oxycarbide glasses. Thus, pore sizes increases from 6 μm at the top evaporation face to 13 μm at the bottom of the samples, and porosities in the corresponding regions decrease from 77% to 63%, respectively. The gradient distribution has been assigned to a gradient concentration of PDMS in the hybrid preceramic material as determined by the elemental analysis. The carbon concentration (free and covalently bonded carbon) in the hybrid materials increases with the sample thickness or height. However, the lower concentration of PDMS molecules found at the bottom of the hybrid samples leads, after pyrolysis, to higher values of retained carbon and pore sizes in the SiOC glasses. An interesting finding is that the gradient PDMS distribution also provokes a gradient nanodomain size of the segregated free carbon as a form of graphite, typical in SiOC glasses.

We have tested the hypothesis that alterations in length dependent activation (LDA) of cardiac myofilaments represent an important regulatory mechanism affecting the Frank-Starling mechanism as determined by the slope (E(es)) of the relation between left ventricular (LV) volume and end-systolic pressure. We employed a transgenic (TG) mouse model in which the cardiac isoform of TnI (cTnI) has been completely replaced with slow skeletal TnI (ssTnI), the embryonic/neonatal isoform in the heart. Compared to non-transgenic (NTG) controls, myofilaments from TG-ssTnI hearts demonstrate an increase in Ca(2+) sensitivity and a substantially blunted LDA that is unaffected by PKA-dependent phosphorylation. We measured in situ LV pressure and volume relations during basal conditions and isoproterenol (ISO) stimulation. In the basal state in TG-ssTnI hearts there was significant increase in end-systolic pressure and slight decrease in heart rate. ISO stimulation resulted in a significant increase in heart rate, ejection fraction, maximum dP/dt, preload-recruitable stroke work, maximum dP/dt versus end diastolic volume and cardiac output in both groups. During basal conditions there was no difference in the E(es) relation between NTG and TG-ssTnI groups. However, during ISO stimulation the E(es) relation was significantly different between NTG and TG-ssTnI groups. Our study provides the first direct evidence that enhancement in differences in LDA between cardiac myofilaments from NTG and TG-ssTnI hearts induced by post-translational modifications of sarcomeric proteins are reflected in the in situ beating heart by a different change in E(es). Thus, changes in LDA should be considered in interpreting results from in situ experiments on inotropic effects associated with physiological and patho-physiological states of the heart.

Surface morphology and electrical performance of Ti/Al/metal/Au multilayer schemes were studied and compared to identify the role of the barrier layer on contact reliability. In this metallization scheme, Ti and Ti–W were tested as intermediate layer, and the optimal annealing parameters to form low-resistance ohmic contact were investigated. Besides, the effect of carrying out two-step annealing method in both metallizations was also evaluated. The result obtained was that the properties of ohmic contacts on n -GaN improved using Ti–W/Au as capping layer on Ti/Al bilayer, in comparison with using Ti/Au one. This enhancement became more evident when performing two-step annealing method. In this particular case, Ti–W-based contact not only delivered lower contact resistance, 0.25 ± 0.01 Ω mm versus 0.35 ± 0.01 Ω mm, but also better surface morphology and line edge definition. All these figures reveal the superior properties of Ti–W as metal barrier in comparison with standard contact based on Ti.

This paper presents the photoluminescence study at 12 K and scanning photoluminescence spectroscopy investigation of the ground and excited states at 80 and 300 K on InAs QDs inserted in In 0.15 Ga 0.85 As / GaAs QW structures and created at different QD growth temperatures. It is shown that investigated structures are characterized by the long range variation of an average QD size in QD ensemble across the wafer. This long range QD size inhomogeneity was used for investigation of the multi-excited state energy trend versus ground state energy (or QD sizes).

Better protective and functional coatings on dental drills are increasingly demanded for their desired mechanical, tribological or chemical properties. We have studied the surface modification of steel dental drills, with an aim to increasing both their cutting life and corrosion resistance in dentistry using low-energy plasma-immersion nitrogen implantation over different temperature ranges. The temperature of the drills was controlled by varying the implantation voltage. Following implantation, tests showed that the microhardness of the nitrided drill surfaces was approximately one order higher than that of untreated drills and the corrosion tolerance was found to increase with growing temperature of the plasma-immersion process.

A study, both theoretical and experimental, of the steady regime of a glow discharge is reported where a nitrogen plasma is produced by a DC power source operating at a constant current through a 200–500 mA range. Two different models of this plasma are developed. The first one was designed to reproduce the V–I characteristic curve where the transition from the background ionization regime to the saturation one takes place, and, from this, to the Townsend and breakdown regimes, respectively. The second model represents the plasma behaviour as that of a voltage operated current source which follows the power law depending on the gas pressure as i(υ) = Aυn(p). The experimental results confirm, to a high degree of coincidence, the predictions made by these models.

NaBH 4 , a safe and high energy density source of H 2 for fuel cells, requires a catalyst for reliable hydrogen production. In this paper we show that Pt and Pd atoms, apparently dispersed elementally, on functionalized surfaces of carbon nanotubes (CNT) leads to the highest value for the figure of merit ( ~ 300 L min − 1 g metal − 1 [NaBH 4 ] −1 ) reported so far in the literature. This result was achieved with a 150 μm thick CNT paper. Thinner paper produces even higher rates of hydrogen generation. The catalyst is robust, continuing to operate without degradation in performance for more than 20 cycles. The kinetic data are analyzed by a combination of first order and zero order reactions. The analysis provides a framework for predicting the performance of the catalyst for fuel cell applications.

The effects of storage time and temperature on blood alcohol concentration were evaluated in this two-part study involving 34 ethanol-negative and 21 ethanol-positive volunteers. Multiple 10-mL Vacutainer(®) blood tubes containing 100 mg of sodium fluoride and 20 mg of potassium oxalate were collected from living persons and subjected to various storage conditions. The time from collection to analysis ranged from 0 to 60 days and storage temperatures ranged from 3 to 20°C. Regardless of the storage conditions, all ethanol-negative samples remained negative (

We present the algorithm based on the Lax pair generalization to reveal some properties of nonautonomous KdV solitons. Starting from the general method of solution for the nonisospectral IST problem, we demonstrate how the varying-coefficient KdV equation can arise in nonuniformed and inhomogeneous media. We write down the one- and two-soliton solution of the nonautonomous varying-coefficient KdV with the time-dependent spectral parameter and consider some special cases of the isospectral solutions of the KdV equation with varying dispersion, nonlinearity, and gain. Finally, we compare these solutions with the nonautonomous solitons of the NLSE emphasizing their common features.

The interpenetration of the main ideas and methods being used in different fields of science and technology has become one of the decisive factors in the progress of science as a whole. Mathematical analogies between different physical systems can be extremely fruitful in understanding the novel physical concepts. Accordingly to the new theory of bio-energy transport along protein molecules in living systems and modified Davydov molecular soliton theory, we propose a nonautonomous model that can be considered as a candidate of the bio-energy transport mechanism in protein molecules. Based on the generalized nonlinear Schrodinger equation model with varying-intime harmonic oscillator potential, we show that conditions of its exact integrability in one-dimensional case indicate conclusively the way for solitonlike pulse generation in polypeptide molecular systems. The most important properties of this soliton transport of bio-energy are related with periodically changed energy-release conditions and the influences of structure nonuniformity in protein molecules. By analogy with the corresponding optical phenomena in inhomogeneous optical fibers with varying properties along the length, we study the main features of modified Davydov soliton on the basis of the unified nonautonomous nonlinear Schrodinger model in the parameters region of the exact integrability of the model under consideration.

The nonlinear Schrodinger equation (NLSE) model with an external harmonic potential is one of the most important in modern science. This model makes it possible to analyze a variety of nonlinear phenomena, in nonlinear optics and laser physics, biophysics and in the theory of Bose-Einstein condensation of atoms. It is shown that the main specific feature of the dynamics of dark GP matter wave solitons in a parabolic trap is the formation of solitons with dynamically changing form-factors producing the periodic variation in the modulation depth (the degree of “blackness”) of dark solitons. In general, the period of dark soliton oscillations in trapping potential depends on the specific conditions of the experiment and does not coincide with the oscillation period of a linear quantum-mechanical oscillator. In the case of an immobile pedestal in the trap, the oscillation period of the black soliton considerably increases because of the periodic transformation of the black soliton to the gray one and vice versa. Surprisingly, that if the dark soliton is superimposed on the base pedestal oscillating in the trap and displaced from the trap center, the oscillation period of the dark soliton coincides with the period of oscillations of the linear harmonic oscillator, while the dynamics of the dark soliton is similar to that of a classical particle obeying the Newton mechanics laws.

In meat brining, the concentration of brine could affect both water and NaCl transport and, consequently, the total length of the treatment and the final quality of the product. In the present work, the kinetics of water and NaCl transport during the brining of pork loin slices in different brine concentrations (50, 100, 150, 200, 240 and 280 kg/m3) were determined (5±1 °C). In the case of moisture content, the brine concentrations of under 200 kg/m3 led to significant (p < 0.05) sample hydration. Close to this concentration, no net water transport took place, and above it, samples were dehydrated. As regards the evolution of NaCl content, the higher the concentration of brine used, the greater the NaCl content in the sample. The identified effective moisture diffusivity showed a tendency to decrease when the brine concentration rose, changing from positive (hydration) to negative values (dehydration). For NaCl, the identified effective diffusivity remained constant with brine concentration (1.90±0.28) 10–10 m2/s.

The hydrolysis and condensation reactions of γ-APS have been studied in different acid content aqueous solution by using Fourier Transform infrared (FT-IR) spectroscopy. The hydrolysis of γ-APS under the studied conditions can be followed by the increase of the ethanol band located at 882 cm−1 and the decrease of the band due to the ρ(CH3) of γ-APS molecules located at 959 cm−1. Hydrolysis reaction is faster by increasing both H2O and acid concentrations, and it is completed when 3 moles of H2O per mole of γ-APS are used. The increase of the vibrational band located at 1146 cm−1 shows that condensation of the hydrolysed γ-APS molecules take place forming linear chains in poorly cross-linked structures. Besides, both 8-membered cyclic siloxane formations and poorly cross-linked structures are formed and increase as the water and acid content are increased. On the other hand, highly connected cross-linked structures do not appear due to the steric hindrance of the non-hydrolysable aminopropyl group. The silanol band shows that hydrolysis is faster than condensation except for samples with the lowest H2O content.

The Arc two-component system is a complex signal transduction system that plays a key role in regulating energy metabolism at the level of transcription in bacteria. This system comprises the ArcB protein, a tripartite membrane-associated sensor kinase, and the ArcA protein, a typical response regulator. Under anoxic growth conditions, ArcB autophosphorylates and transphosphorylates ArcA, which in turn represses or activates the expression of its target operons. Under aerobic conditions, ArcB acts as a phosphatase that catalyzes the dephosphorylation of ArcA-P and thereby releasing its transcriptional regulation. The events for Arc signaling, including signal reception and kinase regulation, signal transmission, amplification, as well as signal output and decay are discussed.

Dielectric barrier discharge cells (DBDCs) have proved their efficiency in the generation of cold plasmas for hazardous organic compound degradation. Here, we describe the design and construction of a dual thermal packed-bed reactor and DBDC-based system to carry out the degradation of hazardous organic compounds in both liquid and gas phases. The main components of this system are: (i) the thermal treatment system, (ii) DBDC and (iii) resonant inverters of low (3.3 kHz) and high (100 kHz) calculated frequencies. The definition of the cell physical parameters considers: (a) a first-order degradation ratio of the compound and (b) the air breakdown at atmospheric pressure as a function of the transport carrier gas. The power consumed by the cells during the discharges was computed theoretically and experimentally. Using the dual system along with a gas chromatography diagnostic system, highly efficient degradations of a test compound (benzene) have been obtained, reaching 99.950% in the case of a cell experimentally operated at 3.3 kHz and up to 99.996% in another one at 94.3 kHz. An additional 3.7 times reduction in the latter case residence time with respect to the low frequency cell has been found.

Photoluminescence and Raman scattering investigations were performed on porous silicon (PSi) films prepared using different electrochemical etching regimes with the aim of obtaining PSi layers with a variation of Si nanocrystallite sizes. Then Schottky barriers were formed using aluminium contact on a porous surface. Schottky diodes were completed by adding aluminium ohmic contacts to the rear side of the p-type silicon substrate. Current voltage characteristics of the Schottky barriers have been investigated in the dark and under light exposition and photocurrent spectra have been obtained. It is shown that some optimal electrochemical etching regime exists (at etching current density of 5 mA/cm 2 ) which allows the preparation of PSi with a small density of surface defects and best diode parameters. Moreover, our results show that it is possible to change the photocurrent spectrum of Schottky diodes based on PSi by the variation of Si nanocrystallite sizes.

The influence of the concentration of triethylborate (TEB) on the surface properties of hybrid materials prepared from tetraethylortosilicate (TEOS) and polydimethylsiloxane (PDMS) has been studied. TEB concentration has been varied between 0 and 30 wt.% respect to the total amount of alkoxyde whereas PDMS concentration has been set at 40 wt.% in all the hybrid samples. Pore size distributions (PSDs), specific surface areas (SSAs) and surface energies have been determined for such materials. PSDs have shown that pore size and pore volume increase with the amount of TEB forming the hybrid, whereas SSAs decrease. Surface energies have been determined by inverse gas chromatography at infinite dilution (IGC-ID) and have been divided into dispersive and specific surface energies. It was also found that TEB affects to both, dispersive and specific surface energies. Dispersive surface energy values increase from 23.23 mJ⋅m−2 for the pure TEOS-PDMS hybrid sample to 31.07 mJ⋅m−2 for the 30wt.% TEB-containing material. This increase has been attributed to the enhanced polarizability of the TEOS-PDMS hybrid when TEB is incorporated into the structure, a result which is consistent with the composition and structural characterization of the studied hybrid materials. Acid and base (kA, kB) surface constants also evidence a correlation with the TEB concentration: kA decreases and kB increases with the increase of TEB in these hybrids, a result which has been assigned to the lower acidity of boranol groups respect to that of silanols. The formation of an hybrid structure of Si–O–Si(PDMS) and B–O–Si(PDMS) bonds has been confirmed by FT-IR spectroscopy by the presence of a band at 850 cm−1 and a shoulder between 930 and 880 cm−1, respectively.

The degradation process of TEOS-PDMS Ormosils containing different amounts of γ -APS has been studied by means of DTA, TG, FTIR and 29Si-NMR measurements. It has been found that the amount of γ -APS improved the thermal properties of Ormosil materials. The increase in γ -APS content causes the increment on the decomposition temperatures and activation energies of the studied Ormosils. These results have been attributed to the favourable effect of γ -APS in the copolymerisation reaction between TEOS and PDMS molecules. 29Si-NMR analyses have shown that the incorporation of γ -APS increases the concentration of D(Q) units in the Ormosil structure, i.e., increases the number of TEOS molecules bonded to PDMS ones. Initial decomposition temperature (IDT), temperature of maximum weight loss rate (T max), integral procedure decomposition temperature (IPDT) and activation energy values (E) were calculated from different equations which described the degradation of these materials. Addition of 10 wt% γ -APS produced an increase of 63∘C in the IDT and of 115 and 110∘C, respectively, for T max and IPDT (up to 478 and 610∘C) compared to the free γ -APS Ormosil. Activation energy values also rise up to 69.4 kJ⋅ mol−1 by introducing 10 wt% of γ -APS.

Three isolates of Histoplasma capsulatum were identified from mice lung, liver, and spleen inoculated with soil samples of the X hotel's ornamental potted plants that had been fertilized with organic material known as compost. The presence of H. capsulatum in the original compost was detected using the dot-enzyme-linked immunosorbent assay. Nested-PCR, using a specific protein Hcp100 coding gene sequence, confirmed the fungal identification associated with an unusual histoplasmosis outbreak in Acapulco. Although, diversity between the H. capsulatum isolate from the hotel and some clinical isolates from Guerrero (positive controls) was observed using random amplification of polymorphic DNA based-PCR, sequence analyses of H-anti and ole fragment genes revealed a high homology (92-99%) between them.

Compared with the adult, neonatal heart muscle is less sensitive to deactivation by acidic pH. We hypothesized that expression of slow skeletal troponin I (ssTnI), the embryonic isoform, in adult heart would help maintain left ventricular (LV) systolic function during respiratory hypercapnia. We assessed LV function by transthoracic 2D-targeted M-mode and pulsed Doppler echocardiography in transgenic (TG) mice in which cardiac TnI was replaced with ssTnI and in nontransgenic (NTG) littermates. Anesthetized mice were ventilated with either 100% oxygen or 35% CO 2 balanced with oxygen. Arterial blood pH with 35% CO 2 decreased to the same levels in both groups of animals. In the absence of propranolol, the LV fractional shortening was higher in TG compared with NTG mice throughout most of the experimental protocol. LV diastolic function was impaired in TG compared with NTG mice both at 100% oxygen and 35% CO 2 because E-to-A wave ratio of mitral flow was significantly lower, and E-wave deceleration time and LV isovolumic relaxation time were longer in TG compared with NTG mice. When compensatory mechanisms that occur through stimulation of β-adrenergic receptors during hypercapnia were blocked by continuous perfusion with propranolol, we found that NTG mice died within 3 to 4 minutes after switching to 35% CO 2 , whereas TG mice survived. Our experiments demonstrate the first evidence that specific replacement of cardiac TnI with ssTnI has a protective effect on the LV systolic function during hypercapnic acidosis in situ.

The Arc two-component system, comprising the ArcB sensor kinase and the ArcA response regulator, modulates the expression of numerous genes in response to the respiratory conditions of growth. Under anoxic growth conditions, ArcB autophosphorylates and transphosphorylates ArcA, which in turn represses or activates its target operons. Under aerobic growth conditions, phosphorylated ArcA (ArcA-P) dephosphorylates and its transcriptional regulation is released. The dephosphorylation of ArcA-P has been shown to occur, at least in vitro, via an ArcA Asp54 -P → ArcB His717 -P → ArcB Asp576 -P → P i reverse phosphorelay. In this study, the physiological significance of this pathway was assessed. The results demonstrate that the receiver and phosphotransfer domains of the tripartite sensor kinase ArcB are necessary and sufficient for efficient ArcA-P dephosphorylation in vivo.

Photoluminescence (PL), Raman scattering and atomic force microscopy (AFM) investigations have been done for porous silicon (PSi) in as-prepared state. The Schottky barrier to porous silicon layer and ohmic electrical contact to p-type Si substrate have been created. Photocurrent spectral response and reverse current-voltage characteristics in the dark and with light exposition have been investigated for these structures. The photoelectric parameters of Schottky barrier have been discussed from the point of view of variation of the sizes of Si nanocrystallites. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

This paper presents the investigation of photoluminescence (PL), connected with ground (GS) and four excited states (1–4-ES) in highly uniform self-assembled InAs quantum dots (QDs) embedded into the In 0.15 Ga 0.8 As layers, using variable pumping power (P) in the range 10–1000 W/cm 2 at the temperature 12 K. The peak positions of GS and ES emission bands depend on an excitation light power. The energy differences between GS and 1–4ES optical transitions are not equidistant and equal to 48.8, 46.5, 40.3 and 33.4 meV, respectively, at highest power level. It was shown that many-particle effects in such high populated QDs is essential and the exchange/correlation and direct Coulomb contributions do not vanish in the investigated strong confined QDs.

The sol–gel method was used to prepare four different silicon–boron containing gels to obtain monolithic Ormoborosil (organically modified borosilicate) materials. These Ormoborosils were treated under flowing nitrogen at different temperatures from 200 to 1100 °C to produce mixed vitreous oxycarbides of silicon and boron. Fourier transform-infrared spectroscopy (FT-IR) was used to study the structural changes that take place at every studied temperature. Results have shown that boron atoms are bonded preferentially to silicon atoms in the PDMS units. The increase of the boron content in the Ormoborosil network produces a decrease of the mineralisation temperature. Moreover, it has been observed that boron promotes the formation of oxycarbide structures and avoids the formation of a free carbon phase in the oxycarbide network.

We present the miscibility gap for the InxGa1−xSbyAs1−y quaternary alloys in the regular solution model. The miscibility gap is described in terms of the minimum condition for the free energy of the two-phase decomposed alloy. The alloys are considered in the simple solution and quasichemical approximations. Interactions between the nearest and next nearest atoms as well as the oscillation motion of atoms are taken into account. The miscibility gap of the InxGa1−xSbyAs1−y alloys is calculated at temperatures of 500, 550, 600 and 650 °C. It is shown that the more correct quasichemical approximation indicates a less extended miscibility gap.

Modelling of the non-equilibrium crystallization of InxGa1?xSbyAs1?y alloys is presented. Formation of the alloy lattice matched to the GaSb or InAs substrate from supercooled liquid solutions is considered. Non-equilibrium crystallization is described by the minimum condition of the Helmholtz free energy of the non-equilibrium heterogeneous system. A simple solution model is used for the liquid and solid phases. The differences in the compositions of the GaSb-?and InAs-rich alloys crystallized from supercooled solutions on 10??C and saturated liquid solutions are demonstrated.

El presente trabajo analiza la relación existente entre el tamaño y uso de la tierra y la degradación en un sector del Departamento Minas, al Noroeste de la Provincia de Neuquén, Argentina (Figura Nº 1). El mismo forma parte de un proyecto mas amplio, cuyo objetivo es el estudio de las causas que generan la degradación de la tierra en la totalidad del Noroeste provincial. Sobre la magnitud de este problema conviene recordar que más de la tercera parte de la superficie terrestre del planeta es árida y en ella el proceso de desertización y degradación se ha intensificado en los últimos decenios. Según las Naciones Unidas, este problema amenaza el porvenir de más de 785 millones de personas, o sea casi el 20% de la población mundial. Siguiendo con el informe de FAO, también se estima que entre 50.000 y 70.000 km2 de tierras útiles dejan de producir cada año por estos motivos. Argentina en general y la Patagonia en particular, no son ajenos a este problema ya que aproximadamente el 75% del territorio nacional se encuentra afectado por crecientes condiciones de aridez. En la Patagonia argentina, el 90% de la superficie (unos 780.000 km2) presenta signos de degradación y de esta superficie, un 30% se encuentra afectado por procesos erosivos severos y graves con tendencia a agravarse.

The photoluminescence (PL) spectra of highly uniform self-assembled InAs quantum dots (QDs) embedded in In0.15Ga0.85As multi-quantum-well (MQW) heterostructures have been investigated at variable temperatures. This paper presents the PL bands, connected with ground (GS) and multi-excited states (ES) in QDs. Not equidistant optical transitions have been revealed. Spectral peak shifts and PL intensity variations in the temperature range 12–220 K for all PL bands are analyzed. The activation energy of the temperature quenching processes for GS and 4 ES optical transitions in InAs QDs are measured. The mechanism of these processes and the positions of the energy levels in QDs are discussed as well.