Directional bremsstrahlung from a Ti laser-produced x-ray source at relativistic intensities in the 3-12 keV range.

Front and rear side x-ray emission from thin titanium foils irradiated by ultraintense laser pulses at intensities up to ≈5 × 10(19) W/cm2 was measured using a high-resolution imaging system. Significant differences in intensity, dimension, and spectrum between front and rear side emission intensity in the 3-12 keV photon energy range was found even for 5 µm thin Ti foils. Simulations and analysis of space-resolved spectra explain this behavior in terms of directional bremsstrahlung emission from fast electrons generated during the interaction process.

Tracking propagation of ultrashort intense laser pulses in gases via probing of ionization.

We use optical interferometry to study the propagation of femtosecond laser pulses in gases. We show the measurements of propagation in a nitrogen gas jet and we compare the results with propagation in He under the same irradiation conditions. We find that in the case of nitrogen, the detailed temporal structure of the laser pulse can be tracked and visualized by measuring the phase and the resulting electron-density map. A dramatically different behavior occurs in He gas jets, where no details of the temporal structure of the laser pulse are visible. These observations are explained in terms of the ionization dynamics of nitrogen compared to helium. These circumstances make N2 gas sensitive to variations in the electric field and, therefore, allow the laser-pulse temporal and spatial structures to be visualized in detail.

Novel x-ray multispectral imaging of ultraintense laser plasmas by a single-photon charge coupled device based pinhole camera.

Spectrally resolved two-dimensional imaging of ultrashort laser-produced plasmas is described, obtained by means of an advanced technique. The technique has been tested with microplasmas produced by ultrashort relativistic laser pulses. The technique is based on the use of a pinhole camera equipped with a charge coupled device detector operating in the single-photon regime. The spectral resolution is about 150 eV in the 4-10 keV range, and images in any selected photon energy range have a spatial resolution of 5 microm. The potential of the technique to study fast electron propagation in ultraintense laser interaction with multilayer targets is discussed and some preliminary results are shown.

Femtosecond interferometry of propagation of a laminar ionization front in a gas.

We use optical interferometry to investigate ultrafast ionization induced by an intense, ultrashort laser pulse propagating in a helium gas. Besides standard phase shift information, our interferograms show a localized region of fringe visibility depletion (FVD) that moves along the laser propagation axis at luminal velocity. We find that such a loss of visibility can be quantitatively explained by the ultrafast change of refractive index due to the field ionization of the gas in the laser pulse width. We demonstrate that by combining the post facto phase shift distribution with the probe pulse transit effect in the ionizing region, the analysis of the observed FVD yields significant information on the ultrafast dynamics of propagation of the ionization front in the gas.

Alzheimer's Disease Risk and Progression: The Role of Nutritional Supplements and their Effect on Drug Therapy Outcome.

Alzheimer's disease (AD) is the most common neurodegenerative disease in the elderly population. Despite significant advancements in understanding the genetic and molecular basis of AD, the pathology still lacks treatments that can slow down or reverse the progression of cognitive deterioration. Recently, the relationship between nutrient deficiency and dementia onset has been highlighted. AD is in fact a multifactorial pathology, so that a multi-target approach using combinations of micronutrients and drugs could have beneficial effects on cognitive function in neurodegenerative brain disorders leading to synaptic degeneration. Primarily, this review examines the most recent literature regarding the effects of nutrition on the risk/progression of the disease, focusing attention mostly on antioxidants agents, polyunsaturated fatty acids and metals. Secondly, it aims to figure out if nutritional supplements might have beneficial effects on drug therapy outcome. Even if nutritional supplements showed contrasting evidence of a likely effect of decreasing the risk of AD onset that could be studied more deeply in other clinical trials, no convincing data are present about their usefulness in combination with drug therapies and their effectiveness in slowing down the disease progression.

The use of real-time reverse transcriptase PCR for the quantification of cytokine gene expression.

Real-time reverse transcriptase polymerase chain reaction (RT-PCR) is becoming a widely used method to quantify cytokines from cells, tissues, or tissue biopsies. The method allows for the direct detection of PCR product during the exponential phase of the reaction, combining amplification and detection in a single step. Using TaqMan chemistry (Applied Biosystems, Foster City, CA) and the ABI Prism 7700 Sequence Detection System (Applied Biosystems), we validated a large panel of murine and human cytokines, as we as other factors playing a role in the immune system, such a chemokines and apoptotic markers. Although the method allows fast, sensitive, and accurate quantification, different control assays are necessary for the method to be reliable. By construction of complementary DNA (cDNA) plasmid clones, standard curves are generated that allow direct quantification of every unknown sample. Furthermore, the choice of a reliable housekeeping gene is very important. Finally, co-amplification of contaminating genomic DNA is avoided by designing sets of primers located in different exons or or intron-exon junctions. In conclusion, the real-time RT-PCF technique is very accurate and sensitive, allows high through put, and can be performed on very small samples. The development of real-time RT-PCR has resulted in an exponential increase in its use over the last couple of years, and the method has undoubtedly become the standard for quantifying cytokine patterns, clarifying many functional properties of immune cells and their associated diseases.

Occurrence of cadaverine in hairy roots of Brugmansia candida.

The polyamine, cadaverine, was detected in transformed root cultures of Brugmansia candida (syn. Datura candida), a Solanaceae which produces the tropane alkaloids scopolamine and hyoscyamine. To the best of our knowledge, this is the first time that the existence of this uncommon polyamine has been detected in a Datura species. Cadaverine, however, could not be found in the whole plant. The occurrence of cadaverine in hairy roots could be a consequence of either the transformation or a response to stress. Also, cadaverine could be participating in other secondary pathways rather than to the tropane alkaloids. The common polyamines, putrescine, spermidine and spermine were also observed.

Hairy roots of Brugmansia candida that grow without agitation: biotechnological implications.

Hairy roots of Brugmansia candida that grew without agitation were obtained. Kinetics of growth and production of the tropane alkaloids scopolamine and hyoscyamine, with and without agitation, were studied. The exponential growth rate was higher in the roots that were exposed to shaking (0.13 d(-1)) than in the nonagitated ones (0.09 d(-1)). The specific production and the levels per flask of both alkaloids were enhanced without shaking. The use of these roots in large-scale productions could be economically advantageous. It remains to be seen if the data obtained in shake flasks can be extrapolated to large-scale bioreactors.

High-energy electron beam production by femtosecond laser interactions with exploding-foil plasmas.

The interaction of an ultraintense, 30-fs laser pulse with a preformed plasma was investigated as a method of producing a beam of high-energy electrons. We used thin foil targets that are exploded by the laser amplified spontaneous emission preceding the main pulse. Optical diagnostics show that the main pulse interacts with a plasma whose density is well below the critical density. By varying the foil thickness, we were able to obtain a substantial emission of electrons in a narrow cone along the laser direction with a typical energy well above the laser ponderomotive potential. These results are explained in terms of wake-field acceleration.

Effect of elicitation on the accumulation of solasodine by immobilized cells of Solanum eleagnifolium Cav.

The effect of a fungal elicitor obtained from Alternaria sp. on growth and solasodine production by free and alginate-entrapped cells of Solanum eleagnifolium Cav. was studied. Fourteen-day-old cultures were elicited with 1% FW/V autoclaved homogenates. The solasodine production increased from 0.9 to 1.5 mg g-1 DW (65%) in suspension cultures and from 0.75 to 1.4 mg g-1 DW (about 95%) in entrapped cells. The maximum accumulation was obtained after 72 h of elicitation. In order to induce alkaloid release from cells (suspension and entrapped cells), permeabilization with 10% dimethylsulfoxide (DMSO) for 30 min was used. In both cases (free and entrapped cells), about 50-60% of intracellular solasodine was released into the medium. The reuse of elicited and permeabilized entrapped cells was also carried out for three production cycles.

Removal of azinphos methyl by alfalfa plants (Medicago sativa L.) in a soil-free system.

The objective of this study was to investigate the removal of azinphos methyl assisted by alfalfa plants, with special emphasis on the effects of this compound on some plant's physiological parameters. Hydroponic cultures of alfalfa (Medicago sativa L., var Romagnola) were employed as a model system. These cultures were exposed to a nutrient medium containing 10 mg/l of azinphos methyl. A first-order kinetic approach was used to describe the removal of azinphos methyl from the solution. After 20 days of culture, the initial amount of azinphos methyl was reduced to non-detectable levels in the presence of plants. In the absence of plants, 20% of azinphos methyl remained in the solution after 30 days of treatment. The half-life of the pesticide was reduced from 10.8 to 3.4 days in the presence of plants. The growth index of alfalfa plants exposed to azinphos methyl was negatively affected. Chlorophyll contents were reduced after 24 h of treatment and thereafter the levels were comparable to that of control plants. The peroxidase activity of alfalfa roots was not affected by the presence of azinphos methyl. In conclusion, alfalfa plants were able to survive when exposed to an effective concentration of 10 mg/l of azinphos methyl in the root zone, with some alterations on their physiological parameters.

Bioactivity of certain medicinal latexes used by the Ese'ejas.

Latexes from Croton erythrochilus, Ficus inspidia and Sapium marmieri used traditionally as medicinal by the Ese'ejas were analyzed for bioactivity. The assays run were: the brine shrimp toxicity microplate bioassay, the wheat rootlet growth inhibition and the DNA-methyl green bioassay. The three latexes showed cytotoxicity to the brine shrimp and concentration-related growth inhibition. No interaction with the DNA-methyl green complex was observed with any of the three latex samples. The field bioassays described has demonstrated to be useful for supporting ethnobotanical information.

Ritual and medicinal plants of the Ese'ejas of the Amazonian rainforest (Madre de Dios, Perú).

The Ese'eja is a hunter-fisher-gatherer tribe of Amerindians which occupies the south-eastern part of Perú. Their culture cannot be disassociated from religious beliefs. Disease can be caused by accident, distraction or indolence, or by evil powers. These evil powers come either from the direct action of a harmful shaman or by interactions with the Devil. A description of shamanic practices is given to elucidate the position of health practices in Ese'eja culture, which includes the use of medicinal and ritual plants. Aspects of ayahuasca (Banisteriopsis caapi (Spruce) Morton, Malpighiaceae) ritual in shaman initiation and in healing rituals are presented. Diagnosis and treatment include invocation to the ayahuasca spirit. Plants used as medicine or invoked for healing are presented.

Biotransformation of hydroquinone by hairy roots of Brugmansia candida and effect of sugars and free-radical scavengers.

Hairy roots of Brugmansia candida were used to bioconvert hydroquinone into arbutin. The highest bioconversion, with the lowest damage to the cells, was attained when concentrations of 20-40 mg/L hydroquinone were used. Sugars (sucrose, glucose, mannitol, and sorbitol) at concentrations of 30-120 g/L enhanced bioconversion, and, of these, sucrose was the most effective. Two different free-radical scavengers were also tested: sodium benzoate and gallic acid. The first one diminished biotransformation efficiency; gallic acid did not affect biotransformation at all. Preliminary permeabilization treatments tested failed to liberate arbutin into the medium, and provoked a total loss in cell viability.

[Biomass production and biological purification of distillation slops in a 2-step process]. / Producción de biomasa y depuración biológica de vinaza de destilería en un proceso de dos etapas.

In order to lower the chemical demand (COD) of slops from cane molasses alcohol a treatment of two steps which allows the production of single cell protein of Candida utilis and Paecilomyces variotii has been performed. Its use reduces the treatment cost. In the first step the slops without sterilization supplemented with ammonium sulphate (5 g.l-1) and dipotassium phosphate (0.5 g.l-1) was inoculated with C. utilis and P. variotii. The yield was 24 and 18 g.l-1 of dry biomass and COD reduction of 36 and 75% respectively. In the second step, the remainder effluents were treated with Aspergillus niger. The final COD reduction attained was 93 and 92% respectively.

[Use of molasses and whey in culture media for the development and production of a toxin from Clostridium perfringens type D]. / Empleo de melaza y suero de queso en medios de cultivo para el desarrollo y produccion de toxina de Clostridum perfringens tipo D.

This work was undertaken to study the use of molasses and cheese whey in culture media for growth and toxigenic activities of C. perfringens type D. Three media were used namely: 1) A modified Gordon medium 2) a molasses medium and 3) a whey medium which composition are shown in Table 1. The experiments were carried out in a 400 ml microfermentor by using 300 ml of media with automatic pH control (7,0 +/- 0,1) at 37 degrees C. Samples were taken for determination of microbial count and toxigenic activity. Fig. 1, 2, and 3 show the results obtained. The toxigenic activities obtained with the molasses and the Gordon media are similar, while it was not detected any activity in the cheese whey medium. It can be concluded that molasses could be a suitable and inexpensive basic component of culture media for toxin production by C. perfringens type D.

[Mutants with high butanol production from a strain of solventogenic Clostridium isolated from olive black-water]. / Mutantes con alta producción de butanol de una cepa de Clostridium solventogénica aislada de alpechín.

Butanol high producing mutants of a solventogenic Clostridium sp. capable of degrading olive black water, were selected according to ethanol or butanol resistance after treatment with N-methyl-N'-nitro-N-nitrosoguanidine. Mutants were quickly screened from isolated colonies and then characterized in standard culture conditions.

[Biodegradation of a lipid-rich effluent by native bacteria]. / Biodegradación de efluente rico en lípidos por bacterias autóctonas.

From samples of effluent derived from a biological treatment plant of a mayonnaise and margarine producing factory, several bacteria strains presenting high lipolytic activities were isolated. The strain having the highest activity was used for treating a typical final effluent and the results obtained were compared with those achieved with Yarrowia lipolytica and Saccharomycopsis lipolytica strains. The isolated strain showed the highest specific capacity for reducing chemical oxygen demand (COD).

In vitro effects of resveratrol on oxidative stress in diabetic platelets.

To evaluate the in vitro effects of resveratrol (RSV) incubation on platelets from compensated and decompensated diabetic patients in order to use it as an adjuvant therapy. The study was performed on 77 diabetic patients and divided into two phases: 29 compensated and 48 decompensated diabetic platelets were analyzed at recruitment (T0) and after in vitro RSV incubation (20 µg/ml) for 3 h at 37 °C (T1). Lipoperoxide and nitric oxide (NO) levels, superoxide dismutase (SOD) and Na(+)/K(+) ATPase activities, total antioxidant capacity (TAC), and membrane fluidity tested by anisotropy of fluorescent probes TMA-DPH and DPH were determined. In vitro RSV incubation counteracts oxidative damage associated with diabetes and its complications; it is able to improve platelet function through augmented membrane fluidity and Na(+)/K(+) ATPase activity; it enhances antioxidant systems' functionality by increasing NO levels, SOD activity, and TAC and by decreasing lipoperoxide levels in both compensated and decompensated patients. Such platelet functionality enhancement suggests a new method of secondary prevention of complications associated with platelet dysfunction. Being free from one of the major risks associated with many antidiabetic agents, it can be assumed that RSV utilization in the diabetic diet may have a preventive and protective role in the progression of diabetic oxidative damage.

Spatially resolved analysis of Kα x-ray emission from plasmas induced by a femtosecond weakly relativistic laser pulse at various polarizations.

Spatially resolved K-shell spectroscopy is used here to investigate the interaction of an ultrashort laser pulse (λ=800 nm, τ=40 fs) with a Ti foil under intense irradiation (Iλ(2)=2×10(18)Wµm(2)cm(-2)) and the following fast electron generation and transport into the target. The effect of laser pulse polarization (p, s, and circular) on the Kα yield and line shape is probed. The radial structure of intensity and width of the lines, obtained by a discretized Abel deconvolution algorithm, suggests an annular distribution of both the hot electron propagation into the target and the target temperature. An accurate modeling of Kα line shapes was performed, revealing temperature gradients, going from a few eV up to 15-20 eV, depending on the pulse polarization. Results are discussed in terms of mechanisms of hot electron generation and of their transport through the preplasma in front of the target.