bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between glass transition temperature and Debye temperature in bulk metallic glasses
Authors: Wang Wei Hua , Wen Ping , Zhao D.Q. , Pan M.X. , Wang Ru Ju
Published: March 2008

The Debye temperature and glass transition temperature of a variety of bulk metallic glasses (BMGs) were determined by acoustic measurement and differential scanning calorimetry, respectively. The relationship between the Debye temperature and glass transition temperature of these BMGs was analyzed, and their observed correlation was interpreted in terms of the characteristics of the glass transition in BMGs.
Silicon Nitride Ceramics with Sodium Ion Conductive Grain Boundary Phase
Authors: Kawaoka Hirokazu , Sekino Tohru , Kusunose Takafumi , Niihara Koichi
Published: March 2008

Sodium ion-conductive silicon nitride ceramic with Na2O–Al2O3–SiO2 glass as the grain boundary phase was fabricated by adding Na2CO3, Al2O3, and SiO2 as sintering additives. The electrical conductivity was two and four orders of magnitude higher than that of Si3N4 ceramic with Y2O3 and Al2O3 additives at 100 and 1000°C, respectively. This result clearly indicates that ionic conductivity can be provided to insulating structural ceramics by modification of the grain boundary phase without dispersion of conductive particles.
Fabrication of Activated Carbon Fibers/Carbon Aerogels Composites by Gelation and Supercritical Drying in Isopropanol
Authors: Fu Ruowen , Zheng Bo , Liu Jie , Weiss Steve , Ying Jackie Y. , Dresselhaus Mildred S. , Dresselhaus Gene , Satcher Joe H. , Baumann Theodore F.
Published: March 2008

Activated carbon fiber/carbon aerogel (ACF/CA) composites were fabricated by gelling a mixture of ACF and resorcinol and furfural, followed by supercritical drying of the mixture in isopropanol. The product then went through carbonization in a nitrogen atmosphere. The fabrication conditions, such as the mass content of R–F, the content of the ACF added, and the gelation temperature, were explored. The textures and pore structures of the ACF/CA composites thus obtained were characterized using transmission electron microscopy, scanning electron microscopy, and a surface area analyzer. The mechanical properties of the samples were assessed primarily through compressive tests. The experimental results indicated that the added ACF disperses uniformly in the resulting ACF/CA composites. The carbon matrix of the ACF/CA composites also consisted of interconnected carbon nanoparticles with sizes in the range of 20 to 30 nm. The ACFs can reinforce the related carbon aerogels when they originally have low mass density and are weak in mechanical strength. When large amounts of ACF were added to the composites, the micropore area and micropore volume of the composites increased, but their external surface area decreased. The mesopore volumes and the related diameters and mesopore size distributions of the ACF/CA composites were mainly affected by the mass density of the composites. The micropore sizes of all the composites were sharply concentrated at about 0.5 nm.
Soft Magnetic Properties of Nanocrystalline Fe–Co–B–Si–Nb–Cu Alloys in Ribbon and Bulk Forms
Authors: Inoue Akihisa , Shen Baolong
Published: March 2008

Ribbon and bulk nanocrystalline body-centered-cubic (bcc) (Fe,Co) alloys exhibiting good soft magnetic properties were synthesized in Fe71.5-xCoxB13.5Si10Nb4Cu1 system by the simple production processes of melt-spinning or casting and annealing. The glass-type alloys were formed in the Co content range below 30 at.%. These glassy alloys crystallized through two exothermic reactions. The first stage was due to the precipitation of nanoscale bcc-(Fe,Co) phase with a grain size of about 10 nm, and the second stage resulted from the decomposition of the remaining amorphous phase to α–(Fe,Co), (Fe,Co)2B, (Fe,Co)23B6, (Fe,Co)3Si, and (Fe,Co)2Nb phases. The glass transition temperature increased from 820 to 827 K with increasing Co content from 5 to 20 at.%, while the supercooled liquid region decreased slightly from 37 to 30 K because of the nearly constant crystallization temperature. By choosing the 10 at.% Co-containing alloy, we produced cylindrical glassy alloy rods 1.0 and 1.5 mm in diameter by copper mold casting. The subsequent annealing for 300 s at 883 K corresponding to the temperature just above the first exothermic peak caused the formation of nanoscale bcc-(Fe,Co) structure. The bcc-(Fe,Co) alloy rods exhibited good soft magnetic properties of 1.26 T for saturation magnetization and 5.0 A/m for coercive force, which were comparable to those for the corresponding bcc-(Fe,Co) alloy ribbon. The nanocrystalline alloy in a bulk form is encouraging for future use as a new type of soft magnetic material that requires three-dimensional shapes.
Synthesis of mesoscopic hollow spheres and inner surface functionalized hollow spheres of titanium dioxide by the liquid phase deposition method
Authors: Aoi Yoshifumi , Kambayashi Hisae , Kamijo Eiji , Deki Shigehito
Published: March 2008

Polystyrene (PS) core–TiO2 shell composite particles and TiO2 hollow spheres were fabricated using the liquid phase deposition (LPD) method. Composite particles were prepared using PS particles as templates. Calcination of the composite particles resulted in TiO2 hollow spheres. Uniform TiO2 hollow spheres were obtained when the reaction time of the LPD process was between 4 and 8 h. Furthermore, we fabricated TiO2 hollow spheres whose inner surfaces were functionalized by Pt particles after platinized PS particles were used as templates. The Pt particles were immobilized on the inner surfaces of the hollow spheres.
Two-step oxygen injection process for growing ZnO nanorods
Authors: Tseng Yung-Kuan , Hsu Hsu-Cheng , Hsieh Wen-Feng , Liu Kuo-Shung , Chen I-Cherng
Published: March 2008

Uniform hexagonal prismatic zinc oxide rods were grown over the entire alumina substrate at 550°C using a two-step oxygen injection process, whether the substrates were coated with a catalyst or not. X-ray diffraction showed that all of the depositions exhibited a preferred orientation in the (002) plane. The influence of oxygen concentration was investigated by changing the oxygen flow rate. Oxygen concentration affected the size of ZnO nanorods, especially the diameter. The ZnO nanorods were further checked using high-resolution transmission electron microscopy, photoluminescence, Raman spectroscopy, and room-temperature ultraviolet lasing. The results showed that the rods were single crystals and had excellent optical properties. By observing the growth process, we found that the diameter increased slowly, but the longitudinal growth rate was very high. The growth of ZnO nanorods revealed that the uniform hexagonal prismatic ZnO nanorods were synthesized through vapor deposition growth and a self-catalyzed vapor–liquid–solid (VLS) process.
Synthesis of hierarchical zinc oxide nanotubes
Authors: Kim Hansoo , Sigmund Wolfgang M.
Published: March 2008

In this paper, we report on the synthesis and structure of hierarchical zinc oxide nanotubes. Hierarchical nanotubes grown by physical vaporization of zinc in the presence of a catalyst were decorated with many secondary zinc oxide nanorods on the outer surface. The axis of these nanotubes with an average diameter of 65 nm was aligned along the c axis of wurtzite zinc oxide. The hierarchical zinc oxide nanotubes, many of which were single crystals, were transparent or opaque, depending on whether they had a zinc layer inside. The opaque nanotubes showed an abrupt change in electronic transmittance during investigation with transmission electron microscopy. The unique structure of the hierarchical ZnO nanotubes and the quantum effect resulting from the reduced dimension will modify the original properties of ZnO, leading to novel applications.
Field-induced strain associated with polarization reversal in a rhombohedral ferroelectric ceramic
Authors: Yang Pin , Burns George R. , Rodriguez Mark A.
Published: March 2008

The polarization reversal process in a rhombohedral ferroelectric ceramic material was investigated using field-induced strain measurements and texture development. Special attention was focused on the difference in the field-induced strains between the first quarter cycle and subsequent loading conditions. Results show that the initial field-induced strain is about twelve times greater than the subsequent strain, which immediately suggests that mechanisms involved in these conditions during the polarization reversal process are different. The difference in the magnitude of field-induced strain is discussed in terms of 180° and non-180° domain reorientation processes.
Dynamic characterization of Portevin–Le Chatelier instabilities occurring in depth-sensing microhardness tests
Authors: Bérces G. , Lendvai J. , Juhász A. , Chinh N.Q.
Published: March 2008

Characteristic properties of plastic instabilities were studied using depth-sensing microhardness experiments on an Al–3.3 wt.% Mg alloy and computer simulations based on a macroscopic dynamic model of the experimental setup. A stepwise increase was observed in the indentation depth versus load (d-F) curves measured in constant loading rate mode, indicating hardness oscillations around a nearly constant value of the conventional dynamic microhardness. These oscillations were correlated with plastic instabilities starting from the contact surface between the sample and the indenter head. Taking into account the experimentally determined connection between the hardness oscillations and the indentation velocity, a dynamic model was proposed for the characterization of instability steps.
Perovskite phase formation and ferroelectric properties of the lead nickel niobate–lead zinc niobate–lead zirconate titanate ternary system
Authors: Vittayakorn Naratip , Rujijanagul Gobwute , Tunkasiri Tawee , Tan Xiaoli , Cann David P.
Published: March 2008

The ternary system of lead nickel niobate Pb(Ni1/3Nb2/3)O3 (PNN), lead zinc niobate Pb(Zn1/3Nb2/3)O3 (PZN), and lead zirconate titanate Pb(Zr1/2Ti1/2)O3 (PZT) was investigated to determine the influence of different solid state processing conditions on dielectric and ferroelectric properties. The ceramic materials were characterized using x-ray diffraction, dielectric measurements, and hysteresis measurements. To stabilize the perovskite phase, the columbite route was utilized with a double crucible technique and excess PbO. The phase-pure perovskite phase of PNN–PZN–PZT ceramics was obtained over a wide compositional range. It was observed that for the ternary system 0.5PNN–(0.5 - x)PZN–xPZT, the change in the transition temperature (Tm) is approximately linear with respect to the PZT content in the range x [H11505] 0 to 0.5. With an increase in x, Tm shifts up to high temperatures. Examination of the remanent polarization (Pr) revealed a significant increase with increasing x. In addition, the relative permittivity ([H9280]r) increased as a function of x. The highest permittivities ([H9280]r [H11505] 22,000) and the highest remanent polarization (Pr [H11505] 25 μC/cm2) were recorded for the binary composition 0.5Pb(Ni1/3Nb2/3)O3–0.5Pb(Zr1/2Ti1/2)O3.
Thermodynamics of the tetragonal-to-monoclinic phase transformation in fine and nanocrystalline yttria-stabilized zirconia powders
Authors: Suresh Arun , Mayo Merrilea J. , Porter Wallace D.
Published: March 2008

The current study uses high-temperature differential scanning calorimetry to document the shift in phase-transformation temperature with particle size throughout a series of alloys in the zirconia–yttria system (0–1.5 mol% yttria). The tetragonal-to-monoclinic (T→M) phase-transformation temperature is seen to vary inversely with particle size. It is shown that a simple thermodynamic approach first proposed by Garvie predicts this inverse linear relationship. Subsequent determination of the key thermodynamic parameters therein (e.g., the surface and volume free energy, enthalpy, and entropy changes involved in the phase transformation) allows a complete predictive equation for the T→M phase transformation in the yttria–zirconia system to be developed as a function of particle size and yttria dopant level. The yttria–zirconia phase diagram is then redrawn with grain size as a third variable. It should be stressed that the current analysis is valid for particulate systems only; a parallel paper tackles the problem for fine-grained yttria–zirconia solids, where the approach is similar, but additional strain energy terms come into play.
Synthesis of SrTiO3 nanoparticle/polymer composite film using direct current field
Authors: Okumura Yasuko , Oi Chifumi , Sakamoto Wataru , Yogo Toshinobu
Published: March 2008

Nanocrystalline SrTiO3 particle/polymer composite film was synthesized from a titanium–organic film and strontium ion in aqueous solution by applying a direct current (dc) field. The titanium–organic precursor was synthesized from acetylacetone-modified titanium isopropoxide and a methacrylate derivative. Ultraviolet treatment of the titanium–organic film decreased the leaching of Ti moieties from the precursor film during dc treatment. Crystalline SrTiO3 particles were formed in the precursor films on stainless-steel substrates under a dc field above 40 °C without a high-temperature process. The size of SrTiO3 particles increased with increasing reaction temperature from 40 to 50 °C at 3.0 V/cm. SrTiO3 particles also increased in size with increasing reaction time from 35 to 60 min at 3.0 V/cm and at 50 °C. SrTiO3 particle/polymer films were synthesized on stainless-steel substrates at 3.0 V/cm and 50 °C for 60 min.
Synthesis of new organic–inorganic hybrids poly[2-hydroxethyl methacrylate (HEMA)-glycidyl methacrylate (GMA)-silica] and their mechanical properties
Authors: Li Shuxi , Samuel Solomon Praveen , Mylonakis Andreas , Shah Apoorva , Hsieh Alex , Patel Alpa , Wei Elizabeth , Baran George , Wei Yen
Published: March 2008

The presence of low-molecular-weight by-products is a major problem in poly[2-hydroxethyl methacrylate (HEMA)-silica] hybrids prepared using sol-gel synthesis. Low-molecular-weight by-products have a detrimental effect on the optical transparency, and mechanical and storage properties of poly(HEMA-silica) hybrids. To solve this problem, a new sol-gel synthesis procedure was developed to prepare organic–inorganic hybrids. Glycidyl methacrylate (GMA) was used as a comonomer to form poly(HEMA-GMA-silica) (PHGS) hybrids. In addition to forming a copolymer, GMA has two more functions. It facilitates the removal of almost all of the low-molecular-weight by-product molecules formed during sol-gel synthesis and also prevents further condensation of free silanol groups during the polymerization, storage, and use. The mechanical properties of PHGS hybrids were evaluated by using compression testing. The mechanical properties of PHGS hybrids were higher compared to Plexiglas G poly(methyl methacrylate), and the hybrids can be synthesized with reproducible mechanical properties.
Synthesis of calcium carbonate capsules in water-in-oil-in-water double emulsions
Authors: Wu G.X. , Ding J. , Xue J.M.
Published: March 2008

Hollow capsules have been intensively investigated due to their high capacity of encapsulating large quantities of guest molecules, making them promising candidate materials for various encapsulation applications. In this work, CaCO3 hollow capsules were successfully synthesized via an emulsion route. The interior hollow structure of the capsules was confirmed by using scanning electron microscopy and transmission electron microscopy (TEM). The vaterite polymorph of the as-synthesized CaCO3 capsules was determined by using x-ray diffraction, high-resolution TEM, and Fourier transform infrared spectroscopy. A self-assembly model was proposed to explain the formation mechanism of the vaterite capsules. By adjusting experimental parameters such as the internal solution amount and the surfactant amount of the double-emulsion system, the average capsule size could be adjusted accordingly. However, the increase in capsule size was at a compensation of size-uniformity degradation. The capsule size uniformity was then further optimized by increasing the magnetic stirring rate. The resultant vaterite capsules demonstrated biodegradability behavior after immersion in phosphate-buffered saline solution, leading to their promising applications in the area of controlled drug delivery.
Fabrication of machinable AlN–BN composites with high thermal conductivity by pressureless sintering turbostatic BN-coated AlN nanocomposite powders
Authors: Kusunose Takafumi , Sekino Tohru , Ando Yoichi , Niihara Koichi
Published: March 2008

To impart machinability to hard and brittle AlN ceramics without losing their high thermal conductivity, a homogeneous dispersion of fine BN particles in an AlN matrix was investigated. A homogeneous dispersion of BN particles was obtained by pressureless sintering of turbostatic BN-coated AlN nanocomposite powder (AlN–BN nanocomposite powder), which was prepared by reducing and heating AlN particles containing a mixture of boric acid, urea, and carbon. Though AlN is slightly oxidized by boric acid during the reduction, the addition of carbon reduced the oxygen content of the AlN–BN composite powder by carbothermal reduction of the oxidized AlN particles. As a result, the thermal conductivity of the sintered material increased with decreasing oxygen content of the nanocomposite powder. AlN–BN nanocomposites containing more than 20 vol% BN showed high strength, machinability, and relatively high thermal conductivity in comparison with the conventional microcomposites.
Effect of temperature on metastable phases induced in silicon during nanoindentation
Authors: Singh Rajnish K. , Munroe Paul , Hoffman Mark
Published: March 2008

Indentations were performed on silicon using a Berkovich indenter at loads up to 12 mN, at temperatures from 20 to 135 °C. Transmission electron microscopy revealed crystalline silicon phases in the residual indentation imprint at and above 35 °C. Also, the first reconfirmation of the occurrence of Si-VIII during unloading was observed at temperatures of 100 and 125 °C. Interestingly, at 125 °C a cavity was also observed, and an unidentifiable phase was observed at 135 °C. The observations show the strong effect of temperature on pressure-induced phase transformation in silicon.
Constraints on removal of Si3N4 film with conformation-controlled poly(acrylic acid) in shallow-trench isolation chemical–mechanical planarization (STI CMP)
Authors: Kim Ye-Hwan , Lee Seung-Mi , Lee Kee-June , Paik Ungyu , Park Jea-Gun
Published: March 2008

The effect of changes in poly(acrylic acid) (PAA) conformation on removal of Si3N4 film was investigated. PAA was used as a passivation agent by adsorption on an Si3N4 film in shallow-trench isolation chemical–mechanical planarization (STI CMP). Adsorption behavior of PAA on the Si3N4 film and the conformation transition were determined by adsorption isotherms and force measurements using atomic force microscopy (AFM) as a function of ionic strength. AFM results revealed that, as ionic strength increases, the repulsive force between the negatively charged carboxylate groups along the backbone of PAA is reduced due to counterion screening and to the changes of PAA conformation from a stretched to a coiled configuration. At high ionic strength, the coiled conformation of PAA formed a dense passivation layer on the Si3N4 film, which led to suppression of the removal rate of Si3N4 film from 72 to 61 Å/min in the STI CMP process.
Characterization of the strain rate dependent behavior of nanocrystalline gold films
Authors: Wang L. , Prorok B.C.
Published: March 2008

The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microtensile technique with applied strain rates on the order of 10−4 to 10−6 s−1. Film thickness ranged from 0.25 to 1.00 μm with corresponding grain sizes of 40 to 100 nm. The plastic properties were found to be particularly sensitive to strain rate, film thickness, and grain size, while the elastic property remained relatively unchanged. The thinner films exhibited significant strain rate sensitivity, while the thicker film exhibited only marginal changes. Hall–Petch boundary hardening was observed and dominated plastic flow at larger strain rates, while diffusion-controlled deformation mechanisms appeared to be activated with increasing influence as strain rate decreased. Analysis of dislocation-based and grain-boundary diffusion-related creep suggested that the films were likely experiencing power-law creep as the dominant deformation mechanism in this grain size regime at lower strain rates.
Transfer behavior in low-amplitude oscillating wear of nanocrystalline copper under oil lubrication
Authors: Zhang Y.S. , Wang K. , Han Z. , Lu K.
Published: March 2008

Nanocrystalline (NC) Cu samples were synthesized by means of surface mechanical attrition treatment, from which a layer of NC structure was formed on a coarse-grained Cu plate. Low-amplitude oscillating wear/fretting behaviors of the NC Cu samples were investigated under oil lubrication in comparison with those of as-annealed coarse-grained Cu samples. It was found the NC Cu possesses a markedly enhanced wear resistance and a higher friction coefficient relative to the coarse-grained Cu. A continuous metal transfer layer is formed on the mating ball after fretting against the NC Cu, while no material transfer occurs for the as-annealed Cu. The effects of experimental parameters and the hardness of Cu samples on the formation of a transfer layer have been systematically investigated. The transfer layer is evidenced to play an important role in the enhanced wear resistance of the NC Cu, but it has a trivial effect on its high friction coefficient.
Composition, particle size, and near-infrared irradiation effects on optical properties of Au–Au2S nanoparticles
Authors: Tan Mei Chee , Ying Jackie Y. , Chow Gan Moog
Published: March 2008

Near-infrared (NIR)-absorbing nanoparticles synthesized by the reduction of tetrachloroauric acid (HAuCl4) using sodium sulfide (Na2S) exhibited absorption bands at ∼530 nm and at the NIR region of 650−1100 nm. A detailed study on the structure and microstructure of as-synthesized nanoparticles was reported previously. The as-synthesized nanoparticles were found to consist of amorphous AuxS (x= ∼2), mostly well mixed within crystalline Au. In this work, the optical properties were tailored by varying the precursor molar ratios of HAuCl4and Na2S. In addition, a detailed study of composition and particle-size effects on the optical properties was discussed. The change of polarizability by the introduction of S in the form of AuxS (x= ∼2) had a significant effect on NIR absorption. Also, it was found in this work that exposure of these particles to NIR irradiation using a Nd:YAG laser resulted in loss of the NIR absorption band. Thermal effects generated during NIR irradiation had led to microstructural changes that modified the optical properties of particles.
Stream Gradient‐Related Movement and Growth of Atlantic Salmon Parr during Winter
Authors: Stickler Morten , Enders Eva C. , Pennell Curtis J. , Cote David , Alfredsen Knut , Scruton David A.
Published: March 2008

There has been considerable focus on winter studies of Atlantic salmonSalmo salarparr during the last two decades. However, a lack of knowledge exists about the linkage between the physical conditions, including ice, and parr behavior in flow environments during the cold season. In this study, the movement and growth of Atlantic salmon parr were studied during winter in two stream sections with different gradients (0.3% and 1.8%) in a small natural river. Passive integrated transponder (PIT) technology was implemented by using both fixed antennae and mobile tracking devices. In the low‐gradient section, the formation of surface ice dominated and created stable conditions, whereas in the high‐gradient section, the formation of anchor ice and anchor ice dams occurred periodically and produced a dynamic environment. The results indicated a relationship between parr movement and river gradient. Movement by parr was negatively correlated with time from autumn to late winter but increased as spring approached. The level of movement was considered low (median = 0.9 m), but larger movements (up to 125.6 m) were recorded, indicating individual variation. Furthermore, parr inhabiting the low‐gradient section with the static ice formation exhibited larger movement than parr in the high‐gradient section with dynamic ice formation. Parr showed high site fidelity to both high‐ and low‐gradient sections but were less attracted to pool habitats. Finally, from late autumn to spring, parr demonstrated a specific growth rate close to 0.0%, indicating suitable conditions in both sections. As this study implies, the complexity of physical conditions during winter may lead to variability in individual fish response (i.e., movements). However, the results also imply that winter is not a limiting factor in parr performance if fish have access to suitable cover, such as areas with low substrate embeddedness.
Dermatophyte susceptibilities to antifungal azole agents tested in vitro by broth macro and microdilution methods
Authors: Siqueira Emerson Roberto , Ferreira Joseane Cristina , Pedroso Reginaldo dos Santos , Lavrador Marco Aurélio Sicchiroli , Candido Regina Celia
Published: March 2008

The in vitro susceptibility of dermatophytes to the azole antifungals itraconazole, fluconazole and ketoconazole was evaluated by broth macro and microdilution methods, according to recommendations of the CLSI, with some adaptations. Twenty nail and skin clinical isolates, four of Trichophyton mentagrophytes and 16 of T. rubrum were selected for the tests. Itraconazole minimal inhibitory concentrations (MIC) varied from < 0.03 to 0.25 µg/mL in the macrodilution and from < 0.03 to 0.5 µg/mL in the microdilution methods; for fluconazole, MICs were in the ranges of 0.5 to 64 µg/mL and 0.125 to 16 µg/mL by the macro and microdilution methods, respectively, and from < 0.03 to 0.5 µg/mL by both methods for ketoconazole. Levels of agreement between the two methods (± one dilution) were 70% for itraconazole, 45% for fluconazole and 85% for ketoconazole. It is concluded that the strains selected were inhibited by relatively low concentrations of the antifungals tested and that the two methodologies are in good agreement especially for itraconazole and ketoconazole.
Febrifugine derivative antimalarial activity: quantum mechanical predictors
Authors: Autreto Pedro Alves da Silva , Lavarda Francisco Carlos
Published: March 2008

Plasmodium falciparum resistant strain development has encouraged the search for new antimalarial drugs. Febrifugine is a natural substance with high activity against P. falciparum presenting strong emetic property and liver toxicity, which prevent it from being used as a clinical drug. The search for analogues that could have a better clinical performance is a current topic. We aim to investigate the theoretical electronic structure by means of febrifugine derivative family semi-empirical molecular orbital calculations, seeking the electronic indexes that could help the design of new efficient derivatives. The theoretical results show there is a clustering in well-defined ranges of several electronic indexes of the most selective molecules. The model proposed for achieving high selectivity was tested with success.
Influenza virus and proteolytic bacteria co-infection in respiratory tract from individuals presenting respiratory manifestations
Authors: Mancini Dalva Assunção Portari , Alves Rosely C. Barbosa , Mendonça Rita Maria Zucatelli , Bellei Nancy J. , Carraro Emerson , Machado Antonia M.O. , Pinto José Ricardo , Mancini Filho Jorge
Published: March 2008

A role for proteolytic bacteria in the exacerbation of influenza virus has been shown in natural hosts such as pigs and humans. Four hundred seven samples were collected from the respiratory tract of individuals presenting clinical manifestations, during influenza season (2003-2005) in São Paulo City. The aim of this study was to evaluate the incidence of determined bacteria co-infecting virus in human respiratory tract. Tests, such as bacteriological, immunofluorescence (IF), RT/PCR and hemagglutination (HA) were used for bacterial and viral investigation. Thirty seven (9.09%) positive for influenza virus were screened by IF. The RT/PCR confirmed the presence of influenza virus in these samples. Bacterial and agar casein tests demonstrated that 18 (48.64%) individuals were infected with proteolytic bacteria such as Staphylococcus spp., Streptococcus spp. and Pseudomonas spp. Among these samples, 13 (35.13%) were co-infected with influenza A virus. Influenza type B, co-infecting bacteria were found in five (13.51%) samples. In vitro the S. aureus protease increased the influenza HA titer after contact for 30 min at 25 ºC. Results revealed the occurrence of co-infection with proteolytic bacteria and influenza in the evaluated individuals. This finding corroborates that virus versus bacteria synergism could be able to potentiate respiratory infection, increasing damage to hosts.
Análise descritiva quantitativa do palmito de pupunheira
Authors: Verruma-Bernardi Marta Regina , Moraes Carla Wilma Santos de , Machado Carla Almeida , Kajishima Shizuko , Costa Ester de Queirós
Published: March 2008

Este estudo foi conduzido para descrever o perfil sensorial do palmito de pupunha. A análise descritiva quantitativa (ADQ) foi utilizada para descrever os atributos sensoriais relacionados à aparência, aroma, e textura de três marcas comerciais de palmito de pupunha. As amostras foram avaliadas por uma equipe selecionada com onze provadores e foram definidos nove atributos sensoriais: cor amarela, aparência uniforme e úmida, aroma e sabor não característicos, sabor acido, residual acido e textura macia. Houve diferenças significativas em seis atributos entre as três marcas testadas. Os provadores descreveram os palmitos de pupunha como: cor amarela clara, aparência uniforme e úmida, aroma e sabor não característicos e sabor ácido com valores intermediários, residual acido e amargor final com valores de pouco e textura muito macia a uma textura intermediária.
Predição da distribuição diamétrica de uma floresta manejada experimentalmente através de um Sistema de Equações Diferenciais
Authors: Azevedo Celso Paulo de , Sanquetta Carlos Roberto , Silva José Natalino Macedo , Machado Sebastião Amaral , Souza Cíntia Rodrigues de , Oliveira Milena Marmentine de
Published: March 2008

Este estudo teve como objetivo principal projetar a distribuição diamétrica da floresta manejada através de um sistema de equações diferenciais de primeira ordem, ajustado para cada tratamento. Os dados básicos foram obtidos no Projeto Bom Manejo (Embrapa Amazônia Oriental/CIFOR/ITTO), na Companhia Florestal Monte Dourado (Jarí), Vitória do Jarí - AP. O delineamento é em blocos ao acaso com três repetições. Os tratamentos são combinações de intensidades de exploração (15%, 25% e 35% do volume total das árvores com mais de 60 cm de DAP) com intensidades de desbastes (0%, 30%, 50% e 70% da área basal original). Utilizou-se como controle a floresta não explorada. Na área experimental estão locadas 40 parcelas permanentes de 1,0 ha cada, sendo 36 exploradas e quatro não exploradas. O povoamento foi medido em 1984, explorado em 1985 e remedido em 1986, 1988, 1990, 1994, 1996 e 2004. Foram medidas todas as árvores com DAP ≥ 20 cm. Conquanto esse sistema de equações mantenha a simplicidade de abordagem do problema inerente aos modelos baseados em matrizes de transição, também apresenta sobre estes últimos a vantagem adicional de permitir a obtenção dos valores das variáveis de estado do sistema para qualquer ponto no tempo, não se restringindo a intervalos múltiplos do intervalo original usado na derivação da matriz de transição. Assim, o método foi constatado para diferentes períodos de avaliações e os resultados mostraram que nem os períodos de projeções mais longos (ponto de equilíbrio) serão suficientes para restaurar as condições iniciais do povoamento.
Plantas, suelos y paisajes: ordenamientos de la naturaleza por los indígenas Miraña de la Amazonía colombiana
Authors: Sánchez Mauricio , Miraña Petei , Duivenvoorden Joost
Published: March 2008

Con base en información obtenida sobre los nombres de todas las plantas con DAP > 2.5 cm (Diámetro a la Altura del Pecho, medido a una altura de 1.3 m) dentro de 30 parcelas de 0.1 ha cada una, y sobre los suelos, la vegetación y el paisaje a lo largo de 8 transectos (entre 2 y 5 km de longitud cada uno), se describen los aspectos más importantes sobre la taxonomía botánica y el ordenamiento o jerarquización del medio ambiente desde la perspectiva de los Indígenas Miraña de la Amazonía central colombiana. A pesar de la pérdida cultural, algunos pocos ancianos guardan como parte de su tradición oral, los elementos básicos de un sistema complejo de conocimiento de su ambiente natural. Se detectó un alto grado de conocimiento sobre las especies vegetales silvestres, la existencia de sistemas nomenclaturales para éstas y para los suelos, y un reconocimiento organizado de paisajes fisiográficos y tipos de vegetación.
Estrutura de florestas secundárias após dois diferentes sistemas agrícolas no nordeste do estado do Pará, Amazônia Oriental
Authors: Rodrigues Mauro Antônio Cavaleiro de Macedo , Miranda Izildinha Souza , Kato Maria do Socorro Andrade
Published: March 2008

O objetivo deste trabalho foi caracterizar e comparar a estrutura de florestas secundárias com quatro anos de idade, que foram formadas após a utilização de dois diferentes sistemas de eliminação da cobertura vegetal - o sistema alternativo (SA) que tritura a biomassa e o sistema tradicional (ST) que utiliza o fogo. O estudo foi conduzido na região Bragantina que está localizada no nordeste do Pará. Para tal, foram selecionadas três áreas amostrais para cada sistema de uso da terra. Dentro de cada área amostral foram alocadas aleatoriamente quatro parcelas de 15 m² (3 x 5 m), totalizando 60 m² por área de estudo e 180 m² por sistema de uso. Foi encontrada uma diversidade média (H') de 2,94 para o SA e 3,32 para o ST, a densidade média foi 459.556 ind. ha-1 no SA e 466.833 ind. ha-1 no ST, a área basal do estrato superior do SA foi de 8,48 m² ha-1 e a do ST 3,07 m² ha-1, a biomassa seca estimada para o SA foi de 6,68 ton ha-1 e 2,80 ton ha-1 para o ST. Ocorreram diferenças estatísticas (ANOVA; P < 0,05) em parâmetros da estrutura vertical e biomassa indicando que o SA facilita o desenvolvimento do componente arbóreo das florestas.
A auto-estima de indivíduos que foram submetidos à cirurgia de revascularização do miocárdio
Authors: Vargas Tatiana Victorelli Pires , Dantas Rosana Aparecida Spadoti , Gois Cristiane Franca Lisboa
Published: March 2008

Estudo descritivo e correlacional com objetivos de medir a auto-estima de indivíduos submetidos à cirurgia de revascularização do miocárdio e correlacionar a auto-estima com variáveis sócio-demográficas e clínicas. Uma amostra de 97 pacientes ambulatoriais foi entrevistada. Os dados foram analisados através de estatística descritiva, teste de Correlação de Pearson, testes Mann-Whitney e Kruskal Wallis. A confiabilidade da escala foi verificada (alfa de Cronbach de 0,79) e a média encontrada para auto-estima foi 32,22 (intervalo possível de 10 a 40). Encontramos correlação, estatisticamente significante, apenas para auto-estima e sexo. Concluímos que os participantes apresentavam elevada auto-estima a qual não estava correlacionada com outras variáveis.
Administração de medicamentos: orientação final de enfermagem para a alta hospitalar
Authors: Miasso Adriana Inocenti , Cassiani Silvia Helena De Bortoli
Published: March 2008

Este estudo avaliou a orientação final de enfermagem para a alta hospitalar quanto à terapêutica medicamentosa em uma clínica de internação hospitalar. A amostra constou de 38 pacientes com alta hospitalar em dezembro de 2001 e fevereiro de 2002 e dos enfermeiros que os orientaram. Para coleta dos dados utilizou-se a técnica de observação não participante. Obtivemos como resultados: locais inadequados para orientação, poucas informações por escrito, curto tempo para orientação e não utilização de estratégias que confirmem o entendimento do paciente quanto as orientações. Conclui-se que estes aspectos possam estar contribuindo para ocorrência de erros de medicação no domicílio, após a alta hospitalar.
Qualidade de vida de estudantes de graduação em enfermagem
Authors: Kawakame Patrícia Moita Garcia , Miyadahira Ana Maria Kazue
Published: March 2008

Este estudo teve como propósito investigar a qualidade de vida de 264 estudantes de Graduação em Enfermagem. Os dados foram coletados por meio de um questionário e um instrumento de medida de qualidade de vida, o IQV de Ferrans e Powers. As médias obtidas dos escores do IQV para os estudantes foram altas e próximas das médias da população geral de Rockford - USA. As médias do IQV nos diferentes anos do curso mostraram queda no decorrer do 2º ano, quando os estudantes são inseridos no campo prático, fornecendo subsídios para possíveis intervenções dos educadores nessa problemática.
Enzyme activities and pectin breakdown of sapodilla submitted to 1-methylcyclopropene
Authors: Morais Patrícia Lígia Dantas de , Lima Luiz Carlos de Oliveira , Miranda Maria Raquel Alcântara de , Alves José Donizete , Alves Ricardo Elesbão , Silva José Daniel
Published: March 2008

The objective of this work was to investigate the influence of 1-methylcyclopropene (1-MCP) at 300 nL L-1 on activities of cell wall hidrolytic enzymes and pectin breakdown changes which Sapodilla (Manilkara zapota cv. Itapirema 31) cell wall undergoes during ripening. Sapodilla were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 hours and then, stored under a modified atmosphere at 25º C for 23 days. Firmness, total and soluble pectin and cell wall enzymes were monitored during storage. 1-MCP at 300 nL L-1 for 12 hours delayed significantly softening of sapodilla for 11 days at 25º C. 1-MCP postharvest treatment affected the activities of cell wall degrading enzymes pectinmethylesterase and polygalacturonase and completely suppressed increases in beta-galactosidase for 8 days, resulting in less pectin solubilization. Beta-galactosidase seems relevant to softening of sapodilla and is probably responsible for modification of both pectin and xyloglucan-cellulose microfibril network.
Comparação bayesiana de modelos de previsão de diferenças esperadas nas progênies no melhoramento genético de gado Nelore
Authors: Silva Fabyano Fonseca e , Sáfadi Thelma , Muniz Joel Augusto , Aquino Luiz Henrique de , Mourão Gerson Barreto
Published: March 2008

O objetivo deste trabalho foi realizar uma análise bayesiana de modelos auto-regressivos de ordem p, AR(p), para dados em painel referentes às diferenças esperadas nas progênies (DEP) de touros da raça Nelore publicados de 2000 a 2006. Neste trabalho, adotou-se o modelo AR(2), indicado pela análise prévia da função de autocorrelação parcial. As comparações entre as prioris, realizadas por meio do Fator de Bayes e do Pseudo-Fator de Bayes, indicaram superioridade da priori independente t-Student multivariada - Gama inversa em relação à priori hierárquica Normal multivariada - Gama inversa e a priori de Jeffreys. Os resultados indicam a importância de se dividir os animais em grupos homogêneos de acordo com a acurácia. Constatou-se também que, em média, a eficiência de previsão dos valores de DEP para um ano futuro foi próxima de 80%.
Avaliação qualitativa e quantitativa da microbiota do solo e da fixação biológica do nitrogênio pela soja
Authors: Souza Rosinei Aparecida de , Hungria Mariangela , Franchini Julio Cezar , Chueire Ligia Maria de Oliveira , Barcellos Fernando Gomes , Campo Rubens José
Published: March 2008

O objetivo deste trabalho foi definir, para as condições edafoclimáticas do Brasil, níveis aceitáveis de dispersão de alguns parâmetros biológicos, utilizados em estudos de impacto ambiental de novas tecnologias usadas na cultura da soja. Dois ensaios com soja convencional e transgênica foram conduzidos em 11 municípios de seis estados e no Distrito Federal; os parâmetros avaliados foram: carbono e nitrogênio da biomassa microbiana, respiração basal e quociente metabólico microbiano, eletroforese do DNA do solo em géis desnaturantes (DGGE), fixação biológica do nitrogênio, população de rizóbios, número e massa de nódulos secos, ocupação dos nódulos pelas estirpes de Bradyrhizobium, massa de matéria seca da parte aérea, nitrogênio total e nitrogênio como ureídos na parte aérea. A variabilidade temporal de: carbono e nitrogênio, da biomassa microbiana, da respiração basal e do quociente metabólico microbiano foi adequada, e o coeficiente de variação máximo aceitável foi estimado em 35%. A homogeneidade entre repetições, tratamentos e coletas foi confirmada por DGGE. Em solos pobres em nitrogênio, os parâmetros de massa de nódulos e massa da parte aérea, com coeficiente de variação máximo de 33 e 18%, respectivamente, foram adequados para avaliar a fixação biológica do N, que contribuiu com 72 a 88% do nitrogênio total da parte aérea.
Cultivo de jundiás alimentados com dietas com casca de soja ou de algodão
Authors: Pedron Fabio de Araújo , Radünz Neto João , Pedron Tatiana Emanuelli , Silva Leila Picolli da , Lazzari Rafael , Corrêia Viviani , Bergamin Giovani Taffarel , Veiverberg Cátia Aline
Published: March 2008

O objetivo deste trabalho foi avaliar o efeito da fibra bruta da dieta, no crescimento, parâmetros digestivos, rendimento e qualidade de carcaça de juvenis de jundiá (Rhamdia quelen) em tanques-rede. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 2x3 (duas fontes - cascas de soja e de algodão - e três níveis de fibra bruta: 4, 7 e 10%), com três repetições. Foram distribuídos 450 peixes (129,11± 7,8 g) ao acaso, em 18 tanques-rede (1 m³), com densidade de 25 peixes por tanque, em viveiro de terra de 0,1 ha. As seguintes variáveis foram avaliadas: peso, comprimento total, ganho de peso, biomassa, sobrevivência, rendimento de carcaça e filé, composição química dos filés, índices digestivo e hepatossomáticos, quociente intestinal. Não foram observadas diferenças no desempenho de crescimento. Peixes alimentados com dietas com casca de soja apresentaram maior quantidade de gordura e minerais nos filés. As fontes e níveis de fibra das dietas testadas não afetam o desempenho produtivo do jundiá.
Emissão de dióxido de carbono após aplicação de dejetos líquidos e cama sobreposta de suínos
Authors: Giacomini Sandro José , Aita Celso
Published: March 2008

O objetivo deste trabalho foi avaliar a emissão de dióxido de carbono, após a aplicação ao solo de dejetos líquidos e cama sobreposta de suínos, na presença de palha de aveia, com e sem incorporação ao solo. O experimento foi conduzido em Argissolo Vermelho distrófico arênico. O delineamento utilizado foi o inteiramente casualizado, com três repetições. Os tratamentos consistiram da aplicação ou não de dejetos líquidos e cama sobreposta de suínos sobre palha de aveia, com e sem incorporação ao solo. Após a aplicação dos tratamentos, iniciou-se a medida da emissão de CO2, continuamente, pelo período de 120 dias. A incorporação dos dejetos de suínos e da palha ao solo aumenta a emissão de CO2 para a atmosfera, em comparação à distribuição desses materiais orgânicos na superfície do solo. A aplicação conjunta dos dejetos líquidos e da cama sobreposta de suínos com a palha não aumenta a emissão de CO2 para a atmosfera, o que indica que esses materiais orgânicos não favorecem a mineralização do carbono presente na palha de aveia.
Hematological, biochemical and ruminant parameters for diagnosis of left displacement of the abomasum in dairy cows from Southern Brazil
Authors: Cardoso Felipe Cardoso de , Esteves Vanessa Sinnott , Oliveira Simone Tostes de , Lasta Camila Serina , Valle Stella Faria , Campos Rómulo , González Félix Hilario Diaz
Published: March 2008

The objective of this work was to evaluate hematological, biochemical and ruminant parameters for diagnosis and treatment of the left displaced abomasum (LDA) in dairy cows, in the Plateau Region of Rio Grande do Sul, Brazil. Ruminant fluid, blood and urine samples were collected from 20 cows suffering LDA and from 20 healthy cows (control). The cows with LDA showed lower values of daily milk production, body weight and corporal condition score. The use of pH reagent strips showed to be functional in the field, when compared to a digital pH meter. Ruminant dynamics was damaged in cows affected by LDA, as it was evidenced by the higher reduction time of methylene blue. Serum values of lactate, beta-hydroxybutyrate, urea, albumin, free fatty acids and cholesterol shows to be auxiliary tools in the LDA characterization.
Casein fractions of ultra high temperature milk with different somatic cell counts
Authors: Fernandes Andrezza Maria , Bovo Fernanda , Moretti Thais Santos , Rosim Roice Eliana , Lima César Gonçalves de , Oliveira Carlos Augusto Fernandes de
Published: March 2008

The objective of this work was to evaluate the effect of somatic cell counts (SCC) in casein fractions of ultra high temperature (UHT) milk. Raw milks were categorized in SCC groups of low (200,000-320,000 cells mL-1), intermediate (380,000-560,000 cells mL-1) and high cells (600,000-800,000 cells mL-1). Five replicates of UHT milks within each SCC category were analyzed for casein fractions after 8, 30, 60, 90 and 120 days of storage through high performance liquid chromatography. SCC showed effect only on beta-casein reduction. SCC in raw milk increases the proteolysis of UHT milk, as a consequence of beta-casein degradation.
Mapeamento semidetalhado do uso da terra do Bioma Cerrado
Authors: Sano Edson Eyji , Rosa Roberto , Brito Jorge Luís Silva , Ferreira Laerte Guimarães
Published: March 2008

O objetivo deste trabalho foi mapear o uso da terra do Bioma Cerrado na escala de 1:250.000. As seguintes classes de uso da terra foram consideradas: culturas agrícolas, pastagens cultivadas, reflorestamentos, áreas urbanas e áreas de mineração. A metodologia envolveu a segmentação de imagens do satélite Landsat, a classificação visual dos segmentos e a análise da exatidão global do mapa final. Aproximadamente 39,5% do Cerrado apresentaram algum tipo de uso de terra. Pastagens cultivadas e culturas agrícolas foram as classes predominantes, com 26,5 e 10,5%, respectivamente.