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  • 1
    Electronic Resource
    Electronic Resource
    Determination of the glass transition and nucleation temperatures in Ge2Sb2Te5 sputtered films (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 697-702 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Amorphous Ge2Sb2Te5 films were prepared by rf sputtering from the bulk alloy. Their electrical and optical properties were analyzed using impedance and optical transmission measurements as a function of temperature. From this analysis, it is found that the glass transition temperature of the as-prepared amorphous films is of about 100 °C. This result is confirmed by calorimetric measurements. Impedance and optical measurements in films measured at temperatures between the glass transition and the crystallization temperatures show the appearance of the nucleation centers. Using models for two-phase materials, the electrical parameters of the crystalline and amorphous phases were estimated and related with structural parameters of the samples. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1427146
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  • 2
    Electronic Resource
    Electronic Resource
    Drude-like behavior of Ge:Sb:Te alloys in the infrared (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 760-765 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical transmittance of Ge:Sb:Te evaporated thin film alloys with different compositions was measured in the wavelength range from 2.5 to 34 μm. The as-deposited films with an amorphous structure were thermally crystallized to achieve the two known crystalline phases: the fcc and the hexagonal at higher treatment temperatures. There are drastic changes in the transmittance spectra of samples with different structural phase, which reflects the differences in their optical constants. For amorphous films, only the frequency independent term in Drude's formula is required to properly describe their transmittance spectra. For samples in the hexagonal and the fcc structures, the transmittance spectra show a metallic and semimetallic behavior, respectively; therefore, the full Drude expression has been used as the general dispersion relation for the optical constants of the films. The electrical conductivity deduced from the Drude expression shows a dependence on Sb concentration in good agreement with previously reported values measured on bulk single crystals. Furthermore, the n and k spectra obtained in the measured infrared range are in good agreement with the values in the visible-UV region, previously measured using spectroscopic ellipsometry. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371937
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  • 3
    Electronic Resource
    Electronic Resource
    Electrical probe with guard and automatic positioner (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 1660-1663 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We present the design and construction of a diagnostic system of the plasma parameters by means of electrical probes. The novelties of the system are the protection provided to the electrical probe with a guard, thus minimizing the probe deterioration, and the automatic positioning device associated with the probe. This system consists of: the electronic instrumentation for the electrical probe bias; two control systems, one for the guard's motion, and another for the positioning of the electrical probe; and finally, a data acquisition system. During the system's operation, and based on the data measured by the electrical probe at different positions where the data acquisition is carried out, the following parameters are available in real time: floating voltage, ion saturation voltage and current, electron temperature, and plasma's voltage and density. The motion of the guard and electrical probe array is programmable up to a maximum speed of 1 cm/s, and the time required for the bias of the probe, the measuring and storing of the signal, and the generation of an ASCII data file is approximately 10 ms. With this system, the duty cycle of the probe is extended due to the shielding provided by the guard. Likewise, the reduction of deposits of spurious materials on the probe results in a more reliable measuring process of the plasma parameters. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150515
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  • 4
    Electronic Resource
    Electronic Resource
    Giant and time-dependent magnetocaloric effect in high-spin molecular magnets (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 3248-3250 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured and calculated the magnetocaloric effect in macroscopic samples of oriented high-spin molecular clusters like Mn12 and Fe8 as a function of the temperature and both the intensity and the sweeping rate of the applied magnetic field. We have observed a high magnetic entropy variation around the blocking temperature of the magnetic moment of molecules and calculated the shift of the entropy variation and cooling temperature, with the sweeping rate of the magnetic field. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1325393
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  • 5
    Electronic Resource
    Electronic Resource
    Response of antioxidative enzymes to plum pox virus in two apricot cultivars (2001)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 111 (2001), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Recent evidence has indicated that activated oxygen species (AOS) may function as molecular signals in the induction of defence genes. 
In the present work, the response of antioxidative enzymes to the plum pox virus (PPV) was examined in two apricot (Prunus armeniaca L.) cultivars, which behaved differently against PPV infection. In the inoculated resistant cultivar (Goldrich), a decrease in catalase (CAT) as well as an increase in total superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR) activities were observed. Ascorbate peroxidase (APX), glutathione reductase (GR) and monodehydroascorbate reductase (MDHAR) did not change significantly in relation to non-inoculated (control) plants. In the susceptible cultivar (Real Fino), inoculation with PPV brought about a decrease in CAT, SOD and GR, whereas a rise in APX, MDHAR and DHAR activities was found in comparison to non-inoculated (control) plants. 
Apricot leaves contain only CuZn-SOD isozymes, which responded differently to PPV depending on the cultivar. Goldrich leaves contained 6 SODs and both SOD 1 and SOD 2 increased in the inoculated plants. In leaves from Real Fino, 5 SODs were detected and only SOD 5 was increased in inoculated plants. 
The different behaviour of SODs (H2O2-generating enzymes) and APX (an H2O2-remover enzyme) in both cultivars suggests an important role for H2O2 in the response to PPV of the resistant cultivar, in which no change in APX activity was observed. This result also points to further studies in order to determine if an alternative H2O2-scavenging mechanism takes place in the resistant apricot cultivar exposed to PPV. On the other hand, the ability of the inoculated resistant cultivar to induce SOD 1 and SOD 2 as well as the important increase of DHAR seems to suggest a relationship between these activities and resistance to PPV. 
This is the first report about the effect of PPV infection on the antioxidative enzymes of apricot plants. It opens the way for the further studies, which are necessary for a better understanding of the role of antioxidative processes in viral infection by PPV in apricot plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2001.1110308.x
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  • 6
    Electronic Resource
    Electronic Resource
    Tolerance of pea (Pisum sativum L.) to long-term salt stress is associated with induction of antioxidant defences (2000)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 23 (2000), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Using two cultivars of Pisum sativum L. with different sensitivity to NaCl, the effect of long-term (15 d) NaCl (70 m M) treatments on the activity and expression of the foliar ascorbate–glutathione cycle enzymes, superoxide dismutase isozymes and their mRNAs was evaluated and related to their ascorbate and glutathione contents. High-speed supernatant (soluble) fractions, enriched for cytosolic components of the antioxidant system, were used. In this fraction from the NaCl-tolerant variety (cv Granada), the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), Mn-superoxide dismutase (Mn-SOD) and dehydroascorbate reductase (DHAR) increased, while CuZn-SOD activity remained constant. In the NaCl-sensitive plants (cv Challis), salinity did not produce significant changes in APX, MDHAR and GR activities. Only DHAR activity was induced in cv Challis, whereas soluble CuZn-SOD activity decreased by about 35%. Total ascorbate and glutathione contents decreased in both cultivars, but the decline was greater in NaCl-sensitive plants. This difference between the two cultivars was more pronounced when the transcript levels of some these enzymes were examined. Transcript levels for mitochondrial Mn-SOD, chloroplastic CuZn-SOD and phospholipid hydroperoxide glutathione peroxidase (PHGPX), cytosolic GR and APX were strongly induced in the NaCl-tolerant variety but not in the NaCl-sensitive variety. These data strongly suggest that induction of antioxidant defences is at least one component of the tolerance mechanism of peas to long-term salt-stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2000.00602.x
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  • 7
    Electronic Resource
    Electronic Resource
    Characteristics of Tortillas Prepared from Dry Extruded Masa Flour Added with Maize Pericarp (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 67 (2002), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Corn flour produced by extrusion was used to evaluate the effect of added maize pericarp (0 to 6%, w/w) on the following parameters: water absorption capacity of dry extruded masa flour (DEMF); weight loss during cooking and dehydration rate (DR) in fresh masa (FM), as well as rollability (R), puffing degree (PD), and cutting force (CF) of tortillas. CF was evaluated after 1 and 24 h of preparation. The viscoamylogram profiles, x-ray diffraction, and crystallinity of DEMF and powdered tortillas were also obtained. The DEMF with 3% (w/w) of pericarp produced the highest tortilla yield, improved the PD, DR, R, and CF characteristics of FM and tortillas, and developed the highest viscosity and a structure with adequate crystallinity to make tortillas with commercial quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2002.tb10303.x
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  • 8
    Electronic Resource
    Electronic Resource
    Studies and Biological Assays in Corn Tortillas Made From Fresh Masa Prepared by Extrusion and Nixtamalization Processes (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 67 (2002), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: : :The nutritional composition and protein efficiency ratio (PER) of raw corn meal and of tortillas prepared by extrusion and nixtamalization processes were determined. Rats were fed with diets containing unprocessed raw corn meal (RCM), tortillas prepared from extruded fresh masa without lime (ET), tortillas made from extruded fresh masa with 0.25% lime content (ETWL), and tortillas made with the traditional nixtamalization method (NT). The ETWL had higher protein (8.50%) and dietary fiber (14.52%) contents than did the NT (8.15% protein and 7.39% dietary fiber). The PER value of the ETWL diet was 14.65% higher (P ≤ 0.05) than that of the RCM diet and equivalent to that of the NT diet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2002.tb09476.x
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  • 9
    Electronic Resource
    Electronic Resource
    Antigenic and allergenic differences between 16 different cultivars of Olea europaea (2002)
    Oxford, UK : Blackwell Science Ltd
    Allergy 57 (2002), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2002.057s71060.x
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  • 10
    Electronic Resource
    Electronic Resource
    Antioxidant enzyme activities in shoots from three mycorrhizal shrub species afforested in a degraded semi-arid soil (2003)
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 118 (2003), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mycorrhizae may help plants to thrive in Mediterranean semi-arid ecosystems by altering antioxidant enzyme activities. Our objective was to determine the influence of mycorrhizal inoculation with an allochthonous arbuscular mycorrhizal (AM) fungus, Glomus claroideum, Schenck & Smith, or with a mixture of native AM fungi, on the activity of antioxidant enzymes from shoots of Olea europaea L. ssp. sylvestris, Retama sphaerocarpa (L.) Boissier and Rhamnus lycioides L. seedlings afforested in a degraded Mediterranean semi-arid soil. One year after planting, shoot biomass of inoculated O. europaea seedlings was about 630%, of non-inoculated plants. Shoot biomass of G. claroideum-colonized R. sphaerocarpa was greater than that of seedlings inoculated with the mixed native AM fungi after 12 months. Inoculation with a mix of native AM fungi was the most effective treatment for increasing shoot biomass and N, P and K contents in shoot tissues of R. lycioides. Both mycorrhizal inoculation treatments increased the nutrient contents in shoots of O. europaea and R. lycioides. In O. europaea plants, the inoculation treatments increased catalase, ascorbate peroxidase and dehydroascorbate reductase activities, but not monodehydroascorbate reductase and glutathione reductase activities. Inoculation with G. claroideum increased the activities of all antioxidant enzymes in R. sphaerocarpa. Monodehydroascorbate reductase, glutathione reductase and superoxide dismutase activities in R. lycioides leaves were preferentially increased by inoculation with the mixture of native AM fungi. This work support the view that increased antioxidant enzyme activities could be involved, at least in part, in the beneficial effects of mycorrhizal colonization on the performance of shrub species grown under semi-arid Mediterranean conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2003.00149.x
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