bluuebunny/crossref_metadata_2025 huggingface dataset:
Manganese and zinc leaf application on common bean grown on a "Cerrado" soil
Authors: Teixeira Itamar Rosa , Borém Aluízio , Araújo Geraldo Antônio de Andrade , Fontes Renildes Lúcio Ferreira
Published: April 2005

The occurrence of micronutrient deficiencies, mainly of manganese (Mn) and zinc (Zn) in "cerrado" soils, has been increasing in several crops, including bean. Such a problem is caused by high rates of liming material applied entirely on the soil surface. In this study, the effects of the leaf application of Mn and Zn rates were evaluated. Three experiments were carried out: two in greenhouse and one under field conditions. The greenhouse experiments were set up using a randomized block design and a 5 x 5 factorial, with three replicates, consisting of five rates of Mn (0, 75, 150, 300, and 600 g ha-1) and five rates of Zn (0, 50, 100, 200, and 400 g ha-1) applied via leaves at the 25th day, or both alternatively parceled at 25 and 35 days after emergency (DAE), respectively, for the first and second experiments. In the field experiment, a randomized block design was used with four replicates, and the same treatments as those used in the greenhouse. Leaf applications performed at 25 and 35 DAE were efficient in correcting the symptoms of the Mn and Zn deficiencies. The combined application of Mn and Zn caused an increase in plant height, primary yield components as number of grains per pod, number of pods per plant, and productivity itself. The maximum technical efficiency was obtained with 315 g ha-1 Mn and 280 g ha-1 Zn for a bean productivity of 2.275 kg ha-1, corresponding to 60% above control.
Impact of the number of Spodoptera frugiperda egg layers on parasitism by Trichogramma atopovirilia
Authors: Beserra Eduardo Barbosa , Parra José Roberto Postali
Published: April 2005

Egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) can be found in several crops attacking Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) eggs. It is therefore necessary to demonstrate the capacity of these natural enemies in suppressing populations of the pest to allow them to be used in biological control programs against that species. This work had the objective of evaluating the impact of egg layer distribution in S. frugiperda egg masses on the parasitism capacity of Trichogramma atopovirilia Oatman & Platner, 1983. Masses containing one, two, and three layers were used as treatments, and 1.6 parasitoid per egg of the pest were released. Parasitism percentage differences were observed among the three types of masses under study, on average 66.24 ± 8.56%, 45.20 ± 6.20%, and 40.10± 3.46% for egg masses with one, two, and three layers, respectively, demonstrating the potential of use of the parasitoid for the control of fall armyworm.
As visões feminina e masculina acerca da participação de mulheres e homens no planejamento familiar
Authors: Marcolino Clarice , Galastro Elizabeth Perez
Published: April 2005

Este artigo analisa os resultados das dissertações de mestrado das autoras. Em uma delas, os sujeitos sociais foram homens, e, na outra, mulheres. Os dois estudos foram qualitativos e utilizaram a abordagem fenomenológica. Ao compararmos os resultados das pesquisas, verificamos temas comuns acerca da participação de homens e mulheres no planejamento familiar, os quais foram analisados sob a perspectiva da categoria gênero. Os resultados apontam para modificações nos papéis que homens e mulheres ocupam em relação à reprodução, sexualidade e vida familiar. Diante dessa nova situação, as autoras sugerem uma reorganização dos serviços de saúde de modo a atender a essas demandas.
A AUTO-ESTIMA EM ADOLESCENTES COM E SEM FISSURAS DE LÁBIO E/OU DE PALATO
Authors: Andrade Denise de , Angerami Emília Luígia Saporiti
Published: April 2005

O auto-conceito é um determinante importante da auto-estima, entre homens e mulheres, isto nos fez refletir sobre o processo de reabilitação das pessoas portadoras de malformação. Utilizamos para mensurar o nível de auto-estima a escala de Janis e Field. Entrevistou-se 608 adolescentes sendo 235 com e 373 sem fissuras de lábio e/ou de palato, entre idades de 17 a 20 anos e de ambos o sexos. Analisando os níveis de auto-estima concluímos que o grupo de adolescentes com fissuras se comporta de forma diferente do grupo sem fissura, ou seja, os portadores de fissuras exibem menores escores de auto-estima.
Lesões ocupacionais afetando a coluna vertebral em trabalhadores de enfermagem
Authors: Parada Elisandra de Oliveira , Alexandre Neusa Maria Costa , Benatti Maria Cecília Cardoso
Published: April 2005

Através do levantamento das comunicações de acidente do trabalho (CAT) de um hospital universitário no período de janeiro de 1990 a dezembro de 1997, analisou-se determinadas características da ocorrência de acidentes do trabalho relacionados com a coluna vertebral em trabalhadores de enfermagem. Verificou-se que nesse período foram notificados 531 acidentes e 37 (7,0%) destes eram acidentes típicos que comprometeram a coluna vertebral. Os resultados indicam subnotificação do acidente e que a categoria mais acometida foi o atendente de enfermagem. Os acidentes ocorreram principalmente pela movimentação e transporte de equipamentos e pacientes e pelas quedas.
Ensino do processo de enfermagem nas escolas de graduação em enfermagem do estado de São Paulo
Authors: Dell'Acqua Magda Cristina Queiroz , Miyadahira Ana Maria Kazue
Published: April 2005

Trata-se de um estudo cujo objetivo foi descrever como é oferecido o ensino do processo de enfermagem nas Escolas de Graduação em Enfermagem, do Estado de São Paulo. A população foi composta de 247 docentes. Na metodologia de estudo foi elaborado um questionário, que foi enviado aos 899 docentes das 32 instituições públicas e privadas de Graduação em Enfermagem, do Estado de São Paulo. Dos resultados, em relação ao ensino do processo de enfermagem, do total de 147 docentes que ministravam algum conteúdo, 66 (44,9%) docentes são de 19 escolas privadas e 81 (55,1%) docentes, de 8 escolas públicas.
Parturiente e equipe obstétrica: a difícil arte da comunicação
Authors: Caron Olga Aparecida Fortunato , Silva Isilia Aparecida
Published: April 2005

O estudo teve como objetivo descrever como ocorre a comunicação entre os profissionais que assistem o parto de baixo risco e a mulher que vivencia o processo de parturição. Os dados foram obtidos por meio da observação participante das situações ocorridas no centro obstétrico de duas instituições e de entrevistas com puérperas. Constatou-se que, entre profissionais e parturientes, prevalece a comunicação não terapêutica, imprimindo à assistência obstétrica um perfil de impessoalidade e exercício de poder do profissional sobre a mulher.
As representações dos técnicos e auxiliares de enfermagem acerca do trabalho em equipe na Unidade de Terapia Intensiva
Authors: Shimizu Helena Eri , Ciampone Maria Helena Trench
Published: April 2005

Este estudo tem por objetivos explicitar e analisar as representações dos técnicos e auxiliares de enfermagem acerca do trabalho em equipe em UTI. Foi utilizada a abordagem qualitativa e, como referencial teórico metodológico, a Teoria das Representações Sociais. O material empírico constou de entrevistas com quatro técnicos e doze auxiliares de enfermagem que atuam nas UTIs de Clínica Médica, Cirúrgica e Pediátrica. Na análise dos dados, foi utilizada a técnica de análise de conteúdo, na modalidade de análise temática. Os resultados evidenciaram que os trabalhadores de enfermagem mantêm interação conflituosa, indicando a necessidade de adoção de modelos de gerenciamento de pessoal mais eficientes que contemplem a gestão de conflitos entre as equipes de enfermagem.
O investimento financeiro em recursos humanos: uma experiência em hospital
Authors: Jericó Marli de Carvalho , Castilho Valéria
Published: April 2005

Este estudo tem por objetivo levantar o montante financeiro que um hospital de ensino de grande porte investiu nos programas de treinamento. Utilizou-se o sistema de custeio por absorção, para analisar sete programas de treinamentos para funcionários, os quais totalizaram 307 treinamentos no ano de 1999. A análise de dados possibilitou concluir que, durante o ano investigado, o investimento foi de R$ 225.493,84, correspondendo a R$ 27,41 por funcionário. Não há dados de outros hospitais brasileiros que possibilitem a comparação desse valor. No entanto, se comparado com a média anual mundial de US$ 252 per capita, o valor encontrado é 9,2 vezes menor. Relacionado à folha de pagamento, esse valor corresponde a 0,32 %, sendo que a média mundial é 2,7%. Este estudo aponta para a necessidade dos Centros de Educação Continuada conhecerem os custos dos programas de treinamento e das organizações hospitalares formalizarem uma política de investimento nesses programas.
A questão ambiental como objeto de atuação da vigilância sanitária: uma análise da inserção das enfermeiras nesse campo
Authors: Ribeiro Maria Celeste Soares , Bertolozzi Maria Rita
Published: April 2005

O presente estudo buscou verificar como enfermeiras que atuam na área da Vigilância Sanitária do Município de São Paulo, tratam as questões relativas ao meio ambiente na sua prática cotidiana. A sua realização foi motivada pela urgente necessidade de conservação do meio ambiente, que vem sendo defendida na agenda das políticas nacionais e internacionais. Em julho-agosto de 1999, foram obtidos depoimentos de 8 enfermeiras, os quais foram analisados segundo técnica de análise de discurso. O desenvolvimento do estudo evidenciou que, em geral, as ações realizadas por essas enfermeiras não têm como finalidade a conservação ambiental, restringindo-se a ações de caráter focal e emergencial.
Composição centesimal, perdas de peso e maciez de lombo (longissimus dorsi) suíno submetido a diferentes tratamentos de congelamento e descongelamento
Authors: PIRES Ivy Scorzi Cazelli , ROSADO Gilberto Paixão , AZEREDO Raquel Monteiro Cordeiro de , NEVES Mariana Braga , MIRANDA Lucilene Soares
Published: April 2005

Foram avaliadas a composição centesimal, as perdas de peso e a maciez de porções de carne suína (Longissimus dorsi) grelhadas, submetidas a dois períodos de estocagem (15 e 60 dias) e descongeladas a 7ºC e 25ºC. Constatou-se que os bifes contendo teores mais elevados de umidade correspondem aos tratamentos com 15 dias de estocagem congelada e descongelamento a 7ºC (59,54%) e com 60 dias de estocagem congelada combinada com descongelamento a 25ºC (60,51%). Amostras armazenadas durante 60 dias apresentaram maior teor de minerais (5,58%) em relação àquelas estocadas por 15 dias (4,51%) (análise realizada em amostras grelhadas e pré-salgadas). Os teores de proteína e lipídios e a maciez não foram afetados por quaisquer dos procedimentos. A utilização de 25ºC para o descongelamento ocasionou maiores perdas de peso (40,19%) que 7ºC (33,17%). Os resultados do presente estudo sugerem a aplicação de períodos curtos de estocagem congelada e descongelamento sob resfriamento.
Alterações metabólicas induzidas pela restrição energética e pela suplementação com vitamina E em ratos submetidos ao exercício
Authors: OLIVEIRA Suzana Lima de , DINIZ Derlange Belizário , AMAYA-FARFAN Jaime
Published: April 2005

Este estudo investigou os efeitos da restrição energética (em carboidratos) e da suplementação com vitamina E em parâmetros metabólicos associados ao exercício físico. Ratos machos Wistar, de onze semanas de idade, após receberem dieta controle, restrita (controle modificada) ou suplementada (controle, adicionada de vitamina E), por cinco meses, foram subdivididos em duas categorias: exercitados e não exercitados. Antes do sacrifício, os ratos do grupo exercitado foram submetidos a exercício em esteira até a exaustão. Determinaram-se glicogênio hepático e muscular, glicemia, insulina plasmática e lactato sanguíneo, e registrou-se o tempo para alcançar a exaustão. A restrição energética aumentou o glicogênio hepático e a resistência ao exercício exaustivo e, quando associada ao exercício, reduziu a glicemia. A suplementação com vitamina E reduziu a resistência à exaustão, quando comparada à restrição energética, mas esta redução não foi significativa em relação à dieta controle. Estes resultados indicam que a restrição energética melhorou o desempenho físico, mas a suplementação com vitamina E não apresentou o mesmo efeito.
Anemia ferropriva e estado nutricional de crianças com idade de 12 a 60 meses do município de Viçosa, MG
Authors: Miranda Adriana da Silva , Franceschini Sylvia do Carmo Castro , Priore Silvia Eloiza , Euclydes Marilene Pinheiro , Araújo Raquel Maria Amaral , Ribeiro Sônia Machado Rocha , Netto Michele Pereira , Fonseca Marília Machado , Rocha Daniela da Silva , Silva Danielle Góes da , Lima Nerilda Martins Miranda , Maffia Úrsula Comastre de Castro
Published: April 2005

Este estudo transversal abrangeu crianças com idade de 12 a 60 meses assistidas pelo serviço público de saúde do município de Viçosa, objetivando avaliar a prevalência de anemia e anemia grave, e a relação entre o estado nutricional e a anemia ferropriva, nessas crianças. Para o diagnóstico de anemia, foi utilizado o beta-hemoglobinômetro (Hemocue), considerando o ponto de corte proposto pela Organização Mundial da Saúde de 11,0 g/dL para anemia, e para a anemia grave considerou-se 9,5g/dL. Das 171 crianças atendidas, 63,2% estavam anêmicas e 43,5% destas apresentavam anemia grave. Analisando o estado nutricional, encontrou-se uma alta porcentagem de crianças desnutridas, sendo considerados os índices de peso/idade, peso/estatura e estatura/idade (11,7%, 7,0% e 5,8%, respectivamente). Observou-se alta prevalência de anemia entre as faixas etárias mais precoces. Não foi verificada associação entre anemia e estado nutricional. Torna-se, portanto, necessário trabalhar de forma preventiva a anemia, bem como alertar os profissionais da área de saúde quanto ao diagnóstico precoce, profilaxia e tratamento.
Neurologic manifestations of AIDS: a review of fifty cases in Santos
Authors: Fragoso Yára Dadalti , Mendes Vanessa , Adamo Ana Paula Margonari , Luciana Paschoareli Bosco , Tavares Carlos Augusto Fernandes
Published: April 2005

OBJECTIVE: To review the neurologic manifestations of AIDS in patients who were admitted to Hospital Guilherme Álvaro (HGA) due to any clinical manifestation of the disease. DESIGN: Case series. PATIENTS: All HIV+ patients admitted to the Faculty Hospital (HGA) between July 96 and April 97 were included in this review. RESULTS: From the 117 HIV+ patients admitted to hospitalization due to AIDS-related symptoms, 50 (42.7%) presented neurologic manifestations. The most prevalent of these was neurotoxoplamosis (68%), but a variety of other neurologic diseases were observed. Only 36% of these 50 patients had neurological signs and symptoms as the main complaint for admission, 12% of the patients had at least complained of some neurologic dysfunction at the time of admission and 10% had no neurologic complaints at all. The remaining 42% (21 patients) only complained of neurologic manifestations of AIDS when specifically asked. CONCLUSIONS: The prevalence of neurologic manifestations of AIDS is very high in patients admitted to hospital. Even in the absence of neurologic-related complaints, these patients have to be carefully questioned and examined in the search for an underlying neurologic complication which may present high morbidity and mortality.
Nutritional evaluation of children with phenylketonuria
Authors: Fisberg Regina Mara , Silva-Fernandes Maria Eugênia da , Schmidt Benjamim José , Fisberg Mauro
Published: April 2005

CONTEXT: Dietary phenylalanine (PA) restriction is the most effective form for reducing its excess in the blood and is the only efficient method for treating phenylketonuria. The diet is complex and should be adapted to combine the patients' eating habits, growth and development. It depends basically on the use of industrialized products as substitutes free of PA for proteins that are not fully supplied. OBJECTIVE: To evaluate the nutritional status of children with phenylketonuria (PKU) by anthropometric measurements and food intake. DESIGN: Cross-sectional study. SETTING: Children with PKU attending the Association of Parents and Friends of Handicapped Children (Associação de Pais e Amigos dos Excepcionais - APAE) and normal children attending at municipal day care centers in São Paulo. PARTICIPANTS: 42 children with PKU and 31 normal children aged 1 to 12 of both sexes were assessed in two groups, under and over 7 years of age. MAIN MEASUREMENTS: Weight and height measurements. RESULTS: Children with PKU ingested calories, calcium, iron, zinc, and copper below the recommended values, whereas the protein intake was within the normal range. Food intake in the group of normal children was within normality rates. The height/weight Z-score means for children with PKU were 0.47 for those under 7 years and 1.86 for 7 year-olds and over; in normal children the means were 0.97 <7 years and 1.54 ³7 years, with no statistically significant difference. The height/age Z-score means were significantly lower in the PKU children <7 years (-1.23) than in the normal controls (0.91). CONCLUSIONS: The data presented demonstrate the importance of nutritional surveillance in patients with PKU so as to support adequacy of nutrient intake and to guarantee growth within the relevant standards.
Pollination of soybean (Glycine max L. Merril) by honeybees (Apis mellifera L.)
Authors: Chiari Wainer César , Toledo Vagner de Alencar Arnaut de , Ruvolo-Takasusuki Maria Claudia Colla , Oliveira Arildo José Braz de , Sakaguti Eduardo Shiguero , Attencia Valeria Maria , Costa Fabiana Martins , Mitsui Marina Hitomi
Published: April 2005

This experiment was carried out to evaluate the effect of the honeybee pollination in the production and quality of soybean seeds (Glycine max L. Merril). Seed production was higher (P=0.0001) in covered areas with honeybee colonies (50.64%) and uncovered areas (57.73%) than in covered areas without honeybee colonies. It could be concluded that honeybees were responsible for 95.5% of the pollination accomplished by insects. The pod number in covered treatment with honeybees was 61.38% higher (P=0.0002) than in the covered treatment without honeybees. The average weight of 100 seeds was larger (P=0.0001) in the area covered without honeybees, and reached 17.8 g. The medium content of crude protein in grains was 36.7% and the average oil content was 20.2%. The germination test did not show differences (P>0.05) among the seeds in different treatments. It was concluded that the honeybee pollination in the soybean increased the seeds production.
Giddens: da ontologia social ao programa político, sem retorno
Authors: Saul Renato P.
Published: April 2005

O texto examina as relações entre a teoria social de Anthony Giddens e o programa da terceira via que marca a inserção do autor como intelectual do Novo Trabalhismo britânico. O objetivo é mostrar que, na construção desse programa, os elementos centrais da crítica da "política democrática ortodoxa" tem sua fundamentação naquela teoria social. O processo de globalização é visto pelo autor como um novo modelo de integração social orientado por laços que se estendem muito além das fronteiras tradicionais das comunidades e das nações, levando em si um novo sentido de organização social e política que desafia as atuais gerações a repensarem as raízes da experiência democrática. Esse é o sentido do programa da terceira via e também o sentido da teoria social de Giddens. Num plano mais geral, observa-se que a teoria e seu programa político delineiam-se no interior da tendência que parece dominar a cena na atualidade, a percepção de um novo ambiente sociológico, onde a indução pelo mercado domina como centro ético-político a partir do qual se processa uma ampla redefinição das relações sociais, políticas e econômicas, tanto no plano local quanto no plano global.
Assays for Cyclic Nucleotide‐Specific Phosphodiesterases (Families 1 to 5)
Authors: Deng Chengjun , Halkowycz Petro , Vivo Michael De
Published: April 2005

The discovery of 3′, 5′‐cyclic nucleotide phosphodiesterase (PDE) activity 40 years ago was crucial in establishing the role of cyclic nucleotides in signal transduction. At present, 11 PDE gene families have been identified, differing in substrate specificity, mechanism of regulation, tissue distribution, cellular compartmentalization, and targeting to specific signal transduction pathways. PDE enzymes are attractive drug targets for a variety of human diseases. Efficient high‐throughput PDE enzyme assays are essential for drug development, as well as for understanding the role of these enzymes in signal transduction pathways. In this unit, two types of PDE enzyme assays are described in detail. The first method is relatively inexpensive and is based on separating radiolabeled cyclic nucleotide monophosphates (cNMPs) from degradation products on alumina columns, whereas the second method is a fluorescence‐based procedure that is better suited for high‐throughput screening.
Measurement and Characterization of Energy Expenditure as a Tool in the Development of Drugs for Metabolic Diseases, such as Obesity and Diabetes
Authors: Alberts Pēteris , Johansson Bo G. , McArthur Robert A.
Published: April 2005

The need for treatment of obesity and obesity‐related diseases, such as type 2 diabetes, has been intensified by the epidemic rise of obesity. Recent advances make possible continuous monitoring of metabolically relevant functions in animals to identify novel thermogenic and anorectic compounds. This unit describes non‐invasive in vivo calorimetric assessment of energy expenditure using measurements of oxygen consumption and carbon dioxide production, complemented by telemetric monitoring of body core temperature and locomotor activity in mice and rats. Reference compounds are used to illustrate the determination of substance‐specific parameters, such as the dose that produces the half‐maximal effect (ED50), the maximal effect, as well as the time of onset and duration of compound action. Indirect calorimetry performed at different temperatures provides information on several other well‐defined parameters, including resting metabolic rate, basal metabolic rate, lower critical temperature, temperature sensitivity, defended body temperature, and respiratory quotient.
Measurement and Characterization of Energy Intake in the Mouse
Authors: Svartengren Jan , Modiri Ali‐Reza , McArthur Robert A.
Published: April 2005

Because of the dramatic increase in obesity and related conditions, such as type 2 diabetes, efforts have intensified to develop medications to assist in losing weight or in minimizing weight gain. To this end, methods that allow for the continuous monitoring of metabolically relevant functions in laboratory animals have been developed to help identify novel anorectic and thermogenic agents. Described in this unit is an in vivo procedure for simultaneous recording of feeding, drinking, and motor activity in mice. Data obtained using reference compounds are presented to illustrate how results are calculated, including the minimum effective dose and the dose producing a half‐maximal effect (ED50), as well as the time of onset and duration of action. Information derived from this procedure reveals the specificity of an anorectic effect, which, when combined with parameters of meal patterns, allows for inferences to be made about the effects of test compounds on satiety and hunger.
Isolation of Clathrin‐Coated Vesicles by Differential and Density Gradient Centrifugation
Authors: Girard Martine , Allaire Patrick D. , Blondeau Francois , McPherson Peter S.
Published: April 2005

Clathrin‐coated vesicles (CCVs) are an important class of transport organelles that mediate the endocytosis of proteins and lipids at the plasma membrane and the transport of proteins from the trans‐Golgi network to the endosomal/lysosomal system. The authors describe a protocol for isolating CCVs from adult rat brain using differential centrifugation, Ficoll and D2O‐sucrose density gradient centrifugation, and velocity sedimentation in linear sucrose gradients. The application of this basic method to the isolation of CCVs from developing rat brains and to the generation of relatively crude CCVs from cultured cells is also described. Furthermore, we describe a protocol in which differential centrifugation and a series of discontinuous sucrose gradients are used to isolate CCVs from rat liver. An approach to analyzing CCV purity by electron microscopy is also described.
Functional Characterization of Proteins Regulating Actin Assembly
Authors: Hertzog Maud , Carlier Marie‐France
Published: April 2005

A very large, ever‐increasing repertoire of actin‐binding proteins regulates the assembly dynamics and the spatial organization of actin filaments, thus orchestrating the motile behavior of the cell. The authors describe a series of biochemical functional assays that allow one to characterize the function of a putative actin‐binding protein in actin filament dynamics. These tests allow the characterization of three types of actin‐binding proteins: G‐actin‐sequestering proteins, profilin‐like proteins, and barbed‐end capping proteins. Biochemical tests include the use of sedimentation of actin filaments, polymerization assays at the barbed or pointed end of actin filaments derived from fluorescently labeled actin, thermodynamic measurements of actin assembly at steady state and during turnover of actin filaments, measurements of nucleotide exchange on G‐actin, and the use of the intrinsic or extrinsic fluorescence of actin to measure direct binding of different protein ligands to G‐actin.
Assembly and Micromanipulation of Xenopus In Vitro–Assembled Mitotic Chromosomes
Authors: Almagro Sébastien , Dimitrov Stefan
Published: April 2005

Mitotic chromosomes have fascinated scientists for several decades. Despite the numerous microscopy studies, chromosome structure is, however, still poorly understood. This is due to both the high complexity of the mitotic chromosomes and the lack of other appropriate techniques suitable for studying their organization. This unit describes a novel physical approach based on measurements of mitotic chromosome elasticity. The elasticity properties are determined by the underlying structure, and knowledge of them has allowed a description of the organization of the mitotic chromosomes and critical analysis of the available models. In this unit, a detailed protocol for the measurements of the elastic response of in vitro assembled mitotic chromosomes in Xenopus egg extract is presented.
Preparation and properties of biodegradable poly(butylene succinate)/starch blends
Authors: Lai S.‐M. , Huang C.‐K. , Shen H.‐F.
Published: April 2005

The vital differences between the use of untreated starch and gelatinized starch in blends with poly(butylene succinate) (Bionolle) were thoroughly examined in this study. The melting temperature decreased slightly with increasing dosages of untreated and gelatinized starch. The added starch perhaps tended to disrupt the intermolecular hydrogen bonding within the Bionolle matrix. On the other hand, a large increase in the crystallinity was seen with the addition of starch. Starch appeared to play a nucleating role in the blends. The trend of the glass‐transition temperature decreasing with the starch level was similar to the trend of the melting temperature. For the same starch content, the glass‐transition temperature showed some variations. For blends containing a certain amount of gelatinized starch, the thermal stability remained to a certain degree but continued to decrease. This was ascribed to the relatively low heat stability of starch. As for the mechanical properties, a significant increase in the tensile strength (up to 2 times) was observed when untreated starch was replaced with gelatinized starch in the blends. Similarly, the tear strength increased up to 1.5 times if gelatinized starch was employed. Apparently, the gelatinization of starch was efficiently achieved for promoting its compatibility with Bionolle. In all cases, the mechanical properties of Bionolle blended with gelatinized starch were better than those of Bionolle blended with untreated starch. A morphological investigation provided evidence in support of these findings. This relatively low‐cost gelatinization approach provides an alternative to a high‐cost compatibilizer approach for improving the performance of biodegradable blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 257–264, 2005
Experimental approach to mechanical property variability through a high‐density polyethylene gas pipe wall
Authors: Kiass N. , Khelif R. , Boulanouar L. , Chaoui K.
Published: April 2005

An experimental investigation was designed to establish the distribution of mechanical properties throughout a high‐density polyethylene (HDPE) gas pipe wall. The proposed approach used a continuous and uniform filament that was automatically machined from the pipe on a precision lathe at a very low cutting speed and an optimal depth of cut to minimize heating and structural disturbances. Typical engineering stress–strain curves, in every layer, were obtained on a testing machine especially designed for polymers, and they were statistically analyzed. The stress–strain behavior of HDPE pipe material could basically be divided into three distinctive zones, the second of which remained important. The average stress level illustrating cold drawing for a given layer was almost constant throughout the pipe wall. The measured stresses and moduli correlated very well with the pipe thickness, and they increased from the outer layers toward the inner layers. This was explained by the crystallinity evolution because the pipe production process was based on a convective water‐cooling system with a temperature gradient, which generated residual stresses. Computed statistical stress–strain correlations at yielding, the onset of cold drawing, and fracture points revealed acceptable linear relations for an error level of p ≤ 0.05. On the other hand, an increasing linear correlation characterized the relationship of the yield stress and elastic modulus. This result was confirmed by literature for standard specimens, prepared by compression molding, that did not represent an actual pipe structure with respect to an extrusion thermomechanical history. Such an approach to mechanical property variability within an HDPE pipe wall highlighted the complexity of the hierarchical structure behavior in terms of stress–strain and long‐term brittle failure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 272–281, 2005
Effect of ground rubber powder and devulcanizates on the properties of natural rubber compounds
Authors: Li Shuyan , Lamminmäki Johanna , Hanhi Kalle
Published: April 2005

Ground rubber powder (GRP) and devulcanized rubber (Dev.R) waste through a continuous shear‐flow reaction were used as fillers for virgin natural rubber. A Horikx plot and the gel fraction proved that both main‐chain scission and crosslink scission occurred during the devulcanization. The cure characteristics, swelling behavior, crosslink density, and mechanical properties were studied. GRP and Dev.R, generated from passenger car and light truck tires, showed applicable mechanical properties in the new rubber compounds, and the compounds containing Dev.R demonstrated better properties than those containing GRP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 208–217, 2005
Preparation, structural characterization, and properties of poly(methyl methacrylate)/montmorillonite nanocomposites by bulk polymerization
Authors: Qu Xiongwei , Guan Tonghua , Liu Guodong , She Qingyan , Zhang Liucheng
Published: April 2005

Poly(methyl methacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were synthesized by a simple technique of a monomer casting method, bulk polymerization. The products were purified by hot acetone extraction and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), examination of their mechanical properties, and light transmittance testing. Although XRD data did not show any apparent order of the MMT layers in the nanocomposites, TEM revealed parallel MMT layers with interlamellar spacings of an average of 9.8 nm and the presence of remnant multiplets of nonexfoliated layers. Therefore, PMMA chains were intercalated in the galleries of MMT. DSC and TGA traces also corroborated the confinement of the polymer in the inorganic layer by exhibiting the increase of glass‐transition temperatures and mass loss temperatures in the thermogram. Both the thermal stability and the mechanical properties of the products appeared to be substantially enhanced, although the light transmittances were not lost. Also, the materials had excellent mechanical properties. Measurement of the tensile properties of the PMMA/MMT nanocomposites indicated that the tensile modulus increased up to 1013 MPa with the addition of 0.6 wt % MMT, which was about 39% higher than that of the corresponding PMMA; the tensile strength and Charpy notched impact strength increased to 88 MPa and 12.9 kJ/m2, respectively. As shown by the aforementioned results, PMMA/MMT nanocomposites may offer new technology and business opportunities. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 348–357, 2005
Developing Promiscuous Glycosidases for Glycoside Synthesis: Residues W433 and E432 in Sulfolobus solfataricus β‐Glycosidase are Important Glucoside‐ and Galactoside‐Specificity Determinants
Authors: Hancock Susan M. , Corbett Kevin , Fordham‐Skelton Anthony P. , Gatehouse John A. , Davis Benjamin G.
Published: April 2005

Two residues that have been implicated in determining the substrate specificity of the thermophilic β‐glycosidase from the archaeon Sulfolobus solfataricus (SsβG), a member of the glycosyl hydrolase family 1, have been mutated by site‐directed mutagenesis so as to create more versatile catalysts for carbohydrate chemistry. The wild‐type and mutated sequences were expressed in E. coli with a His7‐tag to allow one‐step chromatographic purification. The E432C and W433C mutations removed key interactions with the OH‐4 and OH‐3 of the sugar substrates, thus reducing the discrimination of glucose, galactose and fucose with respect to other glycosides. This resulted in two glycosidases with greatly broadened substrate specificities. Observed changes include a 24‐fold increase in Man:Gal activity and an 18‐fold increase in GalA:Gal activity. This promiscuous substrate tolerance was further illustrated by the parallel synthesis of a β‐glycoside library of glucose, galactose, xylose and mannose in one pot at 50 °C, in organic solvent. The synthetic potential of the catalysts was further evaluated through alkyl glycoside transglycosylation yields, including the first examples of synthesis of β‐mannosides and β‐xylosides with SsβG.
Cover Picture: Protein‐Detecting Microarrays: Current Accomplishments and Requirements (ChemBioChem 5/2005)
Authors: Tomizaki Kin‐ya , Usui Kenji , Mihara Hisakazu
Published: April 2005

The cover picture shows an emerging protein‐detecting microarray technology that has the potential to uncover complex protein networks in a miniaturized and parallelized fashion. The microarray system comprises capture agents, such as antibodies, recombinant proteins, and peptides immobilized onto solid surfaces, and provides a large number of important parameters on molecular interactions in a single experiment. The system is supported by three independent but strongly correlated basic technologies that involve screening/production of capture agents, engineering of surface modification methodologies of solid supports, and development of detection methods. Although the system is currently in progress, it could be employed conveniently as a diagnostic/research tool in the near future. Further information on the current accomplishments and requirements of the technology can be found in the Review by Mihara and co‐workers on p. 782 ff.
Actin polymerization promotes the reversal of streaming in the apex of pollen tubes
Authors: Cárdenas Luis , Lovy‐Wheeler Alenka , Wilsen Kathleen L. , Hepler Peter K.
Published: April 2005

Actin polymerization is important in the control of pollen tube growth. Thus, treatment of pollen tubes with low concentrations of latrunculin B (Lat‐B), which inhibits actin polymerization, permits streaming but reversibly blocks oscillatory growth. In the current study, we employ Jasplakinolide (Jas), a sponge cyclodepsipeptide that stabilizes actin microfilaments and promotes polymerization. Uniquely, Jas (2 μM) blocks streaming in the shank of the tube, but induces the formation of a toroidal‐shaped domain in the swollen apex, of which longitudinal optical sections exhibit circles of motion. The polarity of this rotary motion is identical to that of reverse fountain motility in control pollen tubes, with the forward direction occurring at the edge of the cell and the rearward direction in the cell interior. Support for the idea that actin polymerization in the apical domain contributes to the formation of this rotary motility activity derives from the appearance therein of aggregates and flared cables of F‐actin, using immunofluorescence, and by the reduction in G‐actin as indicated with fluorescent DNAse. In addition, Jas reduces the tip‐focused Ca2+ gradient. However, the alkaline band appears in the swollen apex and is spatially localized with the reverse fountain streaming activity. Taken together, our results support the idea that actin polymerization promotes reversal of streaming in the apex of the lily pollen tube. Cell Motil. Cytoskeleton 61:112–127, 2005. © 2005 Wiley‐Liss, Inc.
Ciliary behavior of a negatively phototactic Chlamydomonas reinhardtii
Authors: Josef Keith , Saranak Jureepan , Foster Kenneth W.
Published: April 2005

With an instrument that can record the motion of both cilia of the unicellular alga Chlamydomonas reinhardtii for many hours, the behavioral differences of its two cilia have been studied to determine their specific role in phototaxis. The organism was held on a fixed micropipette with the plane of ciliary beating rotated into the imaging plane of a quadrant photodetector. The responses to square‐wave light patterns of a wide range of temporal frequencies were used to characterize the responses of each cilium. Eighty‐one cells were examined showing an unexpectedly diverse range of responses. Plausible common signals for the linear and nonlinear signals from the cell body are suggested. Three independent ciliary measures—the beat frequency, stroke velocity, and phasing of the two cilia—have been identified. The cell body communicates to the cilia the direction of phototaxis the cell desires to go, the absolute light intensity, and the appropriate graded transient response for tracking the light source. The complexity revealed by each measure of the ciliary response indicates many independent variables are involved in the net phototactic response. In spite of their morphological similarity, the two cilia of Chlamydomonas respond uniquely. Probably the signals from the cell body fan out to independent pathways in the cilia. Each cilium modifies the input in its own way. The change in the pattern of the effective and recovery strokes of each cilium associated with negative phototaxis has been demonstrated and its involvement in phototactic turning is described. Cell Motil. Cytoskeleton 61:97–111, 2005. © 2005 Wiley‐Liss, Inc.
The zero surface tension limit two‐dimensional water waves
Authors: Ambrose D. , Masmoudi N.
Published: April 2005

We consider two‐dimensional water waves of infinite depth, periodic in the horizontal direction. It has been proven by Wu (in the slightly different nonperiodic setting) that solutions to this initial value problem exist in the absence of surface tension. Recently Ambrose has proven that solutions exist when surface tension is taken into account. In this paper, we provide a shorter, more elementary proof of existence of solutions to the water wave initial value problem both with and without surface tension. Our proof requires estimating the growth of geometric quantities using a renormalized arc length parametrization of the free surface and using physical quantities related to the tangential velocity of the free surface. Using this formulation, we find that as surface tension goes to 0, the water wave without surface tension is the limit of the water wave with surface tension. Far from being a simple adaptation of previous works, our method requires a very original choice of variables; these variables turn out to be physical and well adapted to both cases. © 2005 Wiley Periodicals, Inc.
Initial Photoinduced Dynamics of the Photoactive Yellow Protein
Authors: Larsen Delmar S. , van Grondelle Rienk
Published: April 2005

The photoactive yellow protein (PYP) is the photoreceptor protein responsible for initiating the blue‐light repellent response of the Halorhodospira halophila bacterium. Optical excitation of the intrinsic chromophore in PYP, p‐coumaric acid, leads to the initiation of a photocycle that comprises several distinct intermediates. The dynamical processes responsible for the initiation of the PYP photocycle have been explored with several time‐resolved techniques, which include ultrafast electronic and vibrational spectroscopies. Ultrafast electronic spectroscopies, such as pump–visible probe, pump–dump–visible probe, and fluorescence upconversion, are useful in identifying the timescales and connectivity of the transient intermediates, while ultrafast vibrational spectroscopies link these intermediates to dynamic structures. Herein, we present the use of these techniques for exploring the initial dynamics of PYP, and show how these techniques provide the basis for understanding the complex relationship between protein and chromophore, which ultimately results in biological function.
Statistical Evaluation of Single Nano‐Object Fluorescence
Authors: Lippitz Markus , Kulzer Florian , Orrit Michel
Published: April 2005

Single nano‐objects display strong fluctuations of their fluorescence signals. These random and irreproducible variations must be subject to statistical analysis to provide microscopic information. We review the main evaluation methods used so far by experimentalists in the field of single‐molecule spectroscopy: time traces, correlation functions, distributions of “on” and “off” times, higher‐order correlations. We compare their advantages and weaknesses from a theoretical point of view, illustrating our main conclusions with simple numerical simulations. We then review experiments on different types of single nano‐objects, the phenomena which are observed and the statistical analyses applied to them.
Vibronic Transitions in Single Metalloporphyrins
Authors: Lee H. J. , Lee J. H. , Ho W.
Published: April 2005

Structural and electronic properties of single zinc etioporphyrin molecules adsorbed on Al2O3/NiAl(110) were probed by a low‐temperature scanning tunneling microscope (STM). Scanning tunneling spectroscopy (STS) revealed progressions of spectral features corresponding to the vibronic states of individual molecules that depend strongly on the molecular conformations. Vibronic features observed by STS were compared with the results from fluorescence induced by tunneling electrons (tunneling‐induced fluorescence, TIF).
The Study of Protein Folding and Dynamics by Determination of Intramolecular Distance Distributions and Their Fluctuations Using Ensemble and Single‐Molecule FRET Measurements
Authors: Haas Elisha
Published: April 2005

The folding and dynamics of globular proteins is a multidimensional problem. The structures of the heterogeneous population of refolding protein molecules are characterized by multiple distances and time constants. Deciphering the mechanism of folding depends on studies of the processes rather than the folded structures alone. Spectroscopy is indispensable for these sorts of studies. Herein, it is shown that the determination of intramolecular distance distributions by ensemble and single‐molecule FRET experiments enable the exploration of partially folded states of refolding protein molecules.
Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides
Authors: Juodkazytė Jurga , Šebeka Benjaminas , Valsiunas Ignas , Juodkazis Kestutis
Published: April 2005

Iridium oxide films (IROFs) are known to have an enhanced or the so‐called super‐Nernstian (<59 mV/pH) pH‐sensitivity. The intention in the present study was to find out the reasons of such behavior and also to elucidate the nature of iridium anodic oxidation processes. The methods employed were combined cyclic voltammetry and chronopotentiometry. Iridium layers of 0.1 to 0.2 μm thickness, deposited thermally on titanium or gold‐plated titanium substrates, were used for investigations. IROFs on the surface of working electrodes were formed anodically by applying a constant potential in deaerated and oxygen‐containing solutions of 0.5 M H2SO4, 0.1 M KOH and 0.5 M H3PO4+KOH. Linear pH‐dependences of the stationary open‐circuit potential with the slopes close to 59 mV/pH were found for iridium electrode oxidized at 0.4 V–0.8 V (RHE) in deaerated and at 0.8 V–1.2 V (RHE) in O2‐containing solutions. They were attributed to reversible Ir/Ir(OH)3 and Ir/ IrO2⋅nH2O metal‐oxide electrodes, respectively. It has been suggested that the main current peaks seen in the voltammograms of iridium electrode in acid and alkaline solutions are of different nature. The difference between iridium electrode surface states in acid and alkaline solutions has been presumed to be the main reason of super‐Nernstian pH‐sensitivity of the IROFs. On the basis of the results obtained standard potential of Ir/Ir(OH)3 electrode and the solubility product of Ir(OH)3 have been evaluated: $\rm{E_{\rm Ir/Ir(OH)_3}^{\circ}}$=0.78±0.02 V and Ksp=3.3×10−64.
“Central command” and insular activation during attempted foot lifting in paraplegic humans
Authors: Nowak Markus , Holm Søren , Biering‐Sørensen Fin , Secher Niels H. , Friberg Lars
Published: April 2005

The relationship between cardiovascular regulation and brain activation was investigated during attempted foot lifting in paraplegic subjects and during rhythmic handgrip exercise at one‐third of maximum voluntary contraction force. Brain areas of interest were the primary sensory‐motor area and the insula, a hypothesized center for a central nervous feed‐forward mechanism involved in cardiovascular control (“central command”). This mechanism is complementary to the usual known feedback pathways such as skeletal muscle afferent signals. Regional cerebral blood flow (rCBF) was measured in eight normal and three paraplegic subjects using positron emission tomography (PET) and oxygen‐15‐labeled water. Statistical parametric maps were calculated from the images comparing rest and handgrip. Paraplegics were also scanned during attempted foot lifting, a condition without sensory feedback. During activation tasks, heart rate and mean arterial pressure increased. PET activation responses (P< 0.05, corrected for multiple comparisons) were found in the contralateral primary sensory‐motor area, the supplementary motor area, ipsilateral cerebellum, and bilaterally in the insula. A conjunction analysis showing responses common to handgrip and attempted foot lifting revealed activation in the right central insula (P< 0.05, corrected) in concordance with the concept of a central command feed‐forward hypothesis. Hum Brain Mapp 25:259–265, 2005. © 2005 Wiley‐Liss, Inc.