bluuebunny/crossref_metadata_2025 huggingface dataset:
Eficiência fotoquímica em folhas do mamoeiro (Carica papaya L.) cv. Golden durante o estádio reprodutivo e caracterização da ontogenia dos frutos
Authors: Silva Diolina Moura , Santos Ketney Tonetto dos , Duarte Maísa Melo
Published: February 2012

Considerando que a fisiologia do amadurecimento dos frutos do mamoeiro envolve desde a produção de fotoassimilados, para a sua formação e desenvolvimento, até as enzimas que degradarão a parede celular, promovendo o amolecimento da polpa, o objetivo deste trabalho foi avaliar a cinética da emissão da fluorescência da clorofila a em folhas do mamoeiro (Carica papaya L.) cv. Golden durante o período reprodutivo e avaliar os teores de sólidos solúveis (SS), acidez titulável (AT) e atividade da pectinametilesterase (PME) durante a ontogenia dos frutos. Os maiores índices de desempenho fotoquímico (PItotal) foram verificados nos estádios de formação e crescimento dos frutos, devido ao melhor desempenho das reações de oxirredução do fotossistema I [δR0/(1-δR0)]. Maior eficiência fotoquímica das plantas neste período possibilita maior demanda pelo carbono fixado para a síntese de compostos para o metabolismo celular. Em geral, os fotoassimilados são direcionados para os drenos fortes mais próximos, entretanto as sementes têm prioridade, portanto os teores de SS, AT e a atividade da PME na polpa dos frutos permaneceram constantes durante o desenvolvimento dos mesmos, sendo verificadas alterações nestas características somente no estádio de colheita. Estes resultados confirmam a participação da PME como enzima que prepara o substrato para que as demais enzimas pectinolíticas atuem, disponibilizando os ácidos orgânicos desmetilados e o início da degradação dos polissacarídeos da parece celular antes mesmo da colheita.
Avaliação da população de nematóides em bananal com e sem o uso de organomineral
Authors: Ritzinger Cecília Helena Silvino Prata , Fancelli Marilene , Cordeiro Zilton José Maciel , Vieira Rosiane da Silva , Ledo Carlos Alberto da Silva
Published: February 2012

Com a demanda pela produção integrada, o monitoramento torna-se fundamental para reduzir ou substituir insumos poluentes na fertilização e no manejo de pragas. Muitos produtos têm sido aplicados em áreas de produção, sem o devido registro ou conhecimento de sua eficiência ou de seu efeito sobre pragas e inimigos naturais. Nesta região, o uso de organomineral é preconizado como alternativa ao uso de fertilizante e possivelmente com efeito nematicida. As avaliações, para verificar o efeito deste produto, foram realizadas, por meio de cinco coletas, no período de 2008 a 2010, em três propriedades, em bananais, cv. 'Williams', introduzidos há oito e 13 anos, dentro do projeto de Irrigação de Formoso, em Bom Jesus da Lapa-BA. Foram coletadas dez amostras compostas de duas subamostras de solo e raízes, em área com e sem a aplicação de organomineral. As propriedades, três, foram denominadas, área 1, 2 e 3. A analise de variância foi feita considerando: três épocas de avaliação, dois tratamentos (com e sem organomineral) e três propriedades). O nível de dano foi determinado por meio de escala visual e os dados submetidos à ANOVA. Houve interação significativa entre populações de nematoide no ano e propriedade e entre organomineral e propriedade (P<0,01). Não houve correlação entre nível de dano e organomineral nas áreas 1 e 3. Contudo, houve correlação negativa entre o nível de dano e nematoides na presença de organomineral, na área 3 (P<0,01). Meloidogyne spp. foram as espécies que ocorreram em maior população em Bom Jesus da Lapa-BA. A utilização do organomineral não proporcionou redução significativa na população de nematoides. O nível de dano foi baixo, não podendo ser explicado pelo uso do organomineral. O manejo cultural interferiu no desenvolvimento da população de fitonematoides e de nematoides de vida livre.
Control of Guignardia citricarpa by Bacillus subtilis and Trichoderma spp.
Authors: Kupper Katia Cristina , Corrêa Élida Barbosa , Moretto Cristiane , Bettiol Wagner , Goes Antonio de
Published: February 2012

The ability of isolates of Bacillus subtilis and Trichoderma spp. to control citrus black spot (CBS) was investigated in ´Natal´ sweet orange orchards. The first experiment was conducted during the 2001/2002 season and four isolates of B. subtilis (ACB-AP3, ACB-69, ACB-72 and ACB-77), applied every 28 days, alone or in combination were tested and compared with fungicide treatments. Two other experiments were carried out during the 2002/2003 season, where the same isolates of Bacillus and two isolates of Trichoderma (ACB-14 and ACB-40) were tested being applied every 28 days in the second experiment, and every 15 days in the third experiment. In the first experiment, the treatment with ACB-69 differed statistically from the control, but did not differ from other biological control agents or mixture of Bacillus isolates. In the second experiment, the treatments with ACB-69 and ACB-AP3 resulted in smaller disease index compared with the control treatment. However, this result was not repeated in the third experiment, where the isolates were applied every 15 days. Disease severity was high in both evaluated seasons and the fungicide treatment was the most effective for disease control.
Variabilidade genética e fluxo gênico em populações híbridas e silvestres de pupunha acessada com marcadores RAPD
Authors: Santos Ronaldo Pereira , Cristo-Araújo Michelly de , Picanço-Todrigues Doriane , Astolfi Filho Spartaco , Clement Charles Roland
Published: February 2012

As populações híbridas de pupunha (Bactris gasipaes Kunth) acumularam variabilidade genética provenientes de raças primitivas ao seu redor, o que deveria aumentar sua variabilidade. Para testar esta hipótese, avaliou-se a variabilidade genética de populações híbridas por meio de marcadores RAPD utilizando 176 plantas mantidas no Banco Ativo de Germoplasma do INPA, Manaus-AM, sendo quatro populações híbridas [Belém (n=26); Manaus (n=38); Iquitos, Peru (n=41); Yurimáguas, Peru (n=41)], duas populações silvestres (B. gasipaes variedade chichagui) tipos 1 (n=21) e 3 (n=7), e duas amostras de espécie afim, B. riparia, e compararam-se os parâmetros genéticos com estudos das raças primitivas. Oito iniciadores RAPD geraram 88 marcadores polimórficos e 11 monomórficos. O teste de replicabilidade apresentou uma similaridade de Dice 0,67, considerado aceitável. A heterozigosidade média das populações híbridas foi 0,34 e o polimorfismo foi 87,9%, maiores que nas silvestres (0,31; 74,7%). O dendrograma das similaridades de Dice não apresentou grupos que representassem claramente as populações híbridas. O fluxo gênico entre Iquitos e Yurimáguas (Nm=12,75) e entre Iquitos e Manaus (Nm=9,47) foi alto, enquanto o fluxo entre Belém e Manaus (Nm=7,72) foi menor que o esperado, possivelmente devido à influência da raça Solimões. O alto valor de heterozigosidade em Manaus (0,31) parece ser resultado da união de duas dispersões após a domesticação: a do oeste amazônico, com Iquitos e Yurimáguas, e a do leste amazônico, com Belém, que se juntam em Manaus. No entanto, essas populações não apresentaram acúmulo de variabilidade genética tão expressiva para diferenciá-las das raças primitivas.
Preservation of minimally processed 'aurora-1' peaches using additives
Authors: Martins Ramilo Nogueira , Mattiuz Ben-Hur , Santos Leandra Oliveira , Morgado Cristiane Maria Ascari , Mattiuz Claudia Fabrino Machado
Published: February 2012

'Aurora-1' peaches establishes an interesting alternative as a minimally processed product, due to its characteristics like flavor, color, smell, and also because of its handling resistance. However, it has a short shelf life after a fresh-cut due to enzymatic browning and stone cavity collapse. The main purpose of this research was to test the additive with antioxidant effect to prevent browning in minimally processed 'Aurora-1' peaches. The minimal processing consists of washing, sanitizing, peelings and fruit stone extraction. After that, longitudinal cuts were made to obtain eight segments per fruit. The slices were immersed into the following treatment solutions: control (immersion in 2% ascorbic acid); 2% ascorbic acid + 2% calcium chloride; 1% sodium isoascorbate; 1% citric acid; 1% L-cysteine hydrochloride. The products were placed into rigid polystyrene trays branded MEIWA M-54, covered with 14 µm PVC film (OmnifilmTM) and kept in cold storage at 3ºC ± 2ºC and 65% RH for twelve days, and evaluated each three days. Appraised variables were appearance, soluble solids, titratable acidity, soluble carbohydrates and reducing sugars, total and soluble pectin, ascorbic acid, and peroxidase and polyphenol oxidase enzyme activity. L-cysteine gave to the minimally processed products a shelf life of twelve days, limmited by off-flavor. The treatment with ascorbic acid was efficient to maintainthe ascorbic acid content, with a shelf-life of nine days, limited by enzymatic browning.
Adubação fosfatada no meloeiro-amarelo: reflexos na produção e qualidade dos frutos
Authors: Abrêu Francisco Luis Gonçalves de , Cazetta Jairo Osvaldo , Xavier Terezinha Ferreira
Published: February 2012

O melão (Cucumis melo L.) é uma das culturas de grande expressão econômica e social para a região Nordeste do Brasil. Apesar disso e dos baixos níveis de fósforo (P) dos solos tropicais, existem poucas pesquisas sobre adubação com P nesta cultura, embora seja frequentemente mencionado que este nutriente tem papel preponderante na produção e qualidade dos frutos. Neste contexto, objetivou-se com este trabalho avaliar o efeito de doses de P (0; 120; 240; 360 e 480 kg ha-1 de P2O5), na produção e qualidade do melão-amarelo híbrido Goldex F1, nas condições ambientais de Teresina - Piauí. O experimento foi conduzido em um delineamento de blocos ao acaso, com quatro repetições, tendo 40 plantas por parcela. Os frutos foram colhidos aos 75 após o plantio. Foram avaliados os dados médios da produção total, produção de frutos comerciais, massa e número de frutos por planta, comprimento e diâmetro de frutos, espessura da polpa de frutos, sólidos solúveis, acidez titulável e o índice de maturação. A produção total e comercial, assim como a massa e o número de frutos e acidez titulável aumentaram com as doses de P aplicadas até a dose de 278 kg ha-1 de P2O5. Doses acima de 278 kg ha-1 de P2O5 prejudicaram a produtividade de frutos classificados como comerciais. O comprimento, o diâmetro de frutos e a espessura de polpa aumentaram até a dose de 355 kg ha-1 de P2O5, com aumentos pouco expressivos entre 278 e 355 kg ha-1 de P2O5. O teor de sólidos solúveis totais não foi afetado pela adubação fosfatada. Para as condições de fertilidade do solo deste trabalho, recomenda-se uma dose ao redor de 275 kg ha-1 de P2O5.
Sintomas visuais de deficiência de macronutrientes e boro em maracujazeiro-doce
Authors: Freitas Marta Simone Mendonça , Monnerat Pedro Henrique , Carvalho Almy Junior Cordeiro de , Vasconcellos Marcos Antônio da Silva
Published: February 2012

Conduziu-se experimento em casa de vegetação com objetivo de caracterizar sintomas visuais de deficiências de macronutrientes e de B em folhas e frutos de maracujazeiro-doce cultivados em caixas com areia lavada e irrigados com solução nutritiva. Utilizou-se delineamento experimental em blocos casualizados, com oito tratamentos (solução completa, -N, -P, -K, -Ca, -Mg, -S e -B), com quatro repetições. Os sintomas de deficiência observados, entre 85 e 240 dias após a aplicação dos tratamentos, foram: -N: clorose generalizada e queda prematura das folhas e frutos com cor verde- amarelada e aspecto translúcido; -P: folhas velhas com coloração verde-escura brilhante que, com progressão da deficiência, ficavam mais claras; -K: clorose e posterior necrose na porção basal da nervura central das folhas velhas que progrediam para as bordas e queda das folhas e frutos com enrugamento do epicarpo; -Ca: deformação e necrose nas bordas das folhas novas e frutos com rachaduras no epicarpo e no mesocarpo, além de podridão apical; -Mg: folhas velhas com clorose internerval; -S: clorose das folhas novas com pequenas manchas mais claras e -B: folhas novas com aspecto coriáceo e ondulação nos bordos e frutos com faixas marrons de cortiça na casca.
Grafting of Araucaria angustifolia (BERTOL.) kuntze through the four seasons of the year
Authors: Zanette Flávio , Oliveira Liege da Silva , Biasi Luiz Antonio
Published: February 2012

Araucaria angustifolia is an endangered conifer species of South America that has been over exploited for timber. To incentivize Araucaria angustifolia planting is essential and may play a key role on the conservation of this species and the ecosystems that depend on it. Hence, techniques that allow the production of seedlings with attributes that may entice farmers to plant A. angustifolia trees are very important. Grafting may permit the selection of female trees and the production of precocious plants that will produce high quality seeds. The aim of this study was to determine the best season of the year to graft. Three-year-old seedlings were used as rootstock and orthotropic branches of young plants were used for scion collection. The technique used for the grafting was the bark patch. This procedure was carried out in the beginning of each season in 2007 and 2008, with a total of 160 grafted plants. Grafting carried out in the beginning of autumn had a 50 % success rate. Grafting success was negligible for all remaining seasons. In conclusion, grafting through bark patching is a viable technique for the production of A. angustifolia seedlings. Future research should be carried out to produce grafted seedlings in large-scale.
Os retratos de Maria Isabel e Maria Francisca de Bragança, de Nicolas-Antoine Taunay
Authors: Dias Elaine
Published: February 2012

Nicolas-Antoine Taunay, pintor de paisagens francês, também realizou alguns retratos durante sua estadia na corte do Rio de Janeiro. Nessa cidade, em 1816, ele pinta a rainha Carlota Joaquina e todas as suas filhas. Nesse conjunto, dois retratos sobressaem-se de modo especial: os hoje ainda inventariados como de Maria Francisca e de Maria Teresa, mas que provavelmente são o de Maria Isabel e o de Maria Francisca de Assis - princesas que, nesse ano, deixavam o Brasil para casar-se, respectivamente, com Fernando VII, o rei espanhol, e com seu irmão Carlos Isidro de Bourbon. Neste artigo, além de descrevermos os retratos (e analisarmos a questão da identidade das princesas retratadas), abordamos suas funções na sociedade das cortes e os principais artistas do gênero na Europa. Discutimos, também, as hipóteses que permeiam as escolhas de Taunay para sua execução. Nesse sentido, tratamos da possível circulação de tipologias entre Itália, Portugal, Espanha e França, buscando entender a forma como Taunay os realizou e as funções que doravante tais retratos ocupariam nas relações entre o Brasil e a Europa.
Desenhos setecentistas na Sé de Belém
Authors: Derenji Jussara da Silveira
Published: February 2012

Analisando um nicho e desenhos ao seu redor encontrados na restauração, concluída no ano de 2009, da Catedral de Belém (1748-1782), o artigo se ocupa das relações de trabalho artístico na região Norte durante o período colonial. O anonimato das profissões menos valorizadas, como entalhadores, pintores e escultores, exercidas por índios, negros e mestiços, contrasta com a documentação abundante reservada aos grandes nomes do período, a quem, de maneira genérica, é atribuída a autoria das obras. O artigo acompanha a trajetória do arquiteto régio Antonio Landi (1713-1791) e, através das obras dessa igreja, observa as mudanças técnicas e sociais do período de sua construção.
Entre o oficial e o costumeiro: o exercício dos poderes e a espacialização da ruralidade no centro da América do Sul (primeira metade do século XVIII)
Authors: Oliveira Tiago Kramer de
Published: February 2012

Analisamos aqui a relação entre o sistema administrativo português e a formação de ambientes rurais no centro da América do Sul, em territórios que, na primeira metade do século XVIII, integravam o extremo oeste do Estado do Brasil, no âmbito administrativo da capitania de São Paulo. A partir de um enfoque local, examinando correspondências entre autoridades metropolitanas e cartas de sesmarias, este artigo dialoga com a produção histórica sobre a administração portuguesa na América, buscando reconstruir aspectos generalizantes que possam revelar características estruturais da conquista da terra e da formação de ambientes rurais nos territórios portugueses na América.
Ethnic mirrors: self-representations in the Welsh and Mennonite museums in Argentina and Paraguay
Authors: Oleaga Marisa González De , Bohoslavsky Ernesto
Published: February 2012

According to some scholars and philosophers, ethnic identities are the best political, social, economic, ethic (and even aesthetic) alternative to State centralism, which is incapable of dealing with cultural diversity. Ethnic communitarism is then defined as a more authentic, humane, democratic and inclusive form of organization. The Welsh colonies of Chubut (Argentine) and the established Mennonite colonies of the Chaco Region (Paraguay) are two ethnic groups with forms of community life that have been thoroughly studied from different perspectives. However, neither has been analyzed their point of view of alterity or their relation with those who do not belong to the community. In their museums the history of the community is represented, self-images and other people's images are constructed and spread. The interesting part of these stories is not what they say but what they do, the form in which contents are expressed. These communitarian historical museums tell about the past but they mainly have an impact on the present. Like national or even imperial museums, Welsh and Mennonite museums tend to naturalize a particular self-centered, prejudicial and evolutionist point of view that often excludes other perspectives, especially those elaborated by the neighboring indigenous communities. In contrast, we believe it is necessary to take a stance for democratic, horizontal relations between communities and more polyphonic and responsible historical representations.
Impactos das políticas educacionais nas dinâmicas da organização escolar: reflexões na perspectiva do professorado de uma rede municipal
Authors: Molina Rosane Kreusburg , Lopes Rodrigo Alberto , Achilles Helena Soares
Published: February 2012

Este estudo examina impactos de ações decorrentes das políticas educacionais na dinâmica da organização escolar, sob a ótica de um grupo de professores de uma Rede Municipal de Ensino da Região Metropolitana de Porto Alegre. As análises estruturam-se na concepção de mundo vivido (HABERMAS, 1999, 2001), vida da escola (MCLAREN, 1997) e sociologia da organização escolar (BALL, 1989, 2006). As evidências foram coletadas mediante análise de documentos, entrevistas semiestruturadas, narrativas escritas e grupo de discussão. Colabora com o estudo um grupo de professores com dez anos de docência nestas escolas. As reflexões produzidas dão conta de que, ante as ações decorrentes das políticas educacionais, a atitude dos professores é de adesão ou dissidência cuja complexidade, neste estudo, se desmembra em três dimensões qualitativas: participação, imaginação e alienação.
Meta-avaliação: das abordagens às possibilidades de aplicação
Authors: Elliot Ligia Gomes
Published: February 2012

Dada a importância de seus resultados, projetos, programas e serviços dirigidos a diferentes segmentos da sociedade têm sido acompanhados por avaliações que buscam revelar se houve o alcance da desejada qualidade. No entanto, a condução adequada dessas avaliações pode ser posta em cheque, isto é, verificada por meio de meta-avaliações. Meta-avaliação foi definida como a avaliação de uma avaliação. Assim, o presente artigo apresenta algumas abordagens que representam a contribuição de diversos autores para a realização de meta-avaliações. São abordagens aplicáveis a meta-avaliações somativas e formativas. Algumas indicações de meta-avaliações já desenvolvidas fazem parte do artigo, que destaca as possibilidades de utilização da última versão publicada dos padrões internacionais de avaliação, do Joint Committee on Standards for Educational Evaluation.
A carência de professores de ciências e matemática na Educação Básica e a ampliação das vagas no Ensino Superior
Authors: Araujo Renato Santos , Vianna Deise Miranda
Published: February 2012

Este estudo parte das estatísticas do Instituto Nacional de Estudos e Pesquisas Anísio Teixeira sobre o Ensino Superior, para responder questões de estudo que envolvem: a dimensão da carência de professores no país, o crescimento da oferta de vagas nas licenciaturas presenciais, e a distância e as estimativas sobre o volume total de vagas necessárias para que o país possa formar licenciados em número suficiente para atender a Educação Básica. Metodologicamente, este trabalho se apresenta como um estudo documental alicerçado na análise sistematizada de documentos, estatísticas e artigos da literatura. Os dados estatísticos sobre vagas, candidatos, ingressos, matrículas e concluintes são então apresentados e discutidos quantitativamente, buscando-se elementos que fundamentem as considerações feitas para o fortalecimento das políticas públicas na área. As conclusões apontam que medidas complementares à ampliação de vagas nos cursos de licenciatura são necessárias para a solução da carência de professores no Brasil.
Dynamic Modeling as a Cognitive Regulation Scaffold for Developing Complex Problem-Solving Skills in an Educational Massively Multiplayer Online Game Environment
Authors: Eseryel Deniz , Ge Xun , Ifenthaler Dirk , Law Victor
Published: February 2012

Following a design-based research framework, this article reports two empirical studies with an educational MMOG, called McLarin's Adventures, on facilitating 9th-grade students' complex problem-solving skill acquisition in interdisciplinary STEM education. The article discusses the nature of complex and ill-structured problem solving and, accordingly, how the game-based learning environment can facilitate complex problem-solving skill acquisition. The findings of the first study point to the importance of supporting cognitive regulation of students for successful complex problem-solving skill acquisition in digital game-based learning. The findings of the follow-up study show that when scaffolded by dynamic modeling, students made significant improvement in their complex problem-solving outcomes. Implications drawn from the findings of these two studies are discussed related to: (1) educational game design strategies to effectively facilitate complex problem-solving skill development; and (2) stealth or embedded assessment of progress in complex problem solving during digital game-based learning.
The Video Comprehension Strategies of Chinese-Speaking University Students
Authors: Lin Lu-Fang
Published: February 2012

This study reports the strategies used by second language learners to comprehend computerized video material. In total, 211 students taking an English course in a public university in Taiwan joined the study, conducted over 1 academic year during which 63 students were involved in the pilot study in the first semester, and 148 joined the formal study in the second semester. The pilot study was conducted to identify distinct video comprehension (VC) strategies in order to develop a VC strategy questionnaire. There were two dimensions to the VC strategies: verbal and nonverbal. These two dimensions were further divided into three subcategories: compensation, memory, and cognition. In the formal study, each participant viewed three video clips, then completed self-reports and the newly developed questionnaire. The questionnaire data were analyzed quantitatively to investigate the most and least frequently employed verbal and nonverbal strategies, and the three subcategories. In general, there was no significant difference in the application of the two kinds of strategies. However, use of the memory category strategies outnumbered that of the compensation and cognitive category strategies. The self-report data were also analyzed qualitatively.
Affecting Factors and Outcome on Intermittent Internet Pulling Behavior in Taiwan's Undergraduate Students
Authors: Yang Hui-Jen , Lay Yun-Long
Published: February 2012

Nowadays people's lives heavily rely on Internet facilities. Internet users generally have constant Internet connectivity and intermittently click on sites they want to access even amidst studying or working. In this study, we sought to examine the factors affecting intermittent Internet pulling behavior on undergraduate students. Furthermore, the relationship between intermittent Internet pulling behavior and academic achievement was also investigated. We surveyed 508 undergraduate students by questionnaire to elicit data. The results found prior network experience, peer influence, and curiosity have separate effects on intermittent Internet pulling behavior, but the network efficacy does not significantly affect intermittent Internet pulling behavior. Additionally, intermittent Internet pulling behavior has a negative influence on academic achievement. Some implications for research and practice are also highlighted in this study.
An Evaluation of the Conditions, Processes, and Consequences of Laptop Computing in K-12 Classrooms
Authors: Cavanaugh Cathy , Dawson Kara , Ritzhaupt Albert
Published: February 2012

This article examines how laptop computing technology, teacher professional development, and systematic support resulted in changed teaching practices and increased student achievement in 47 K-12 schools in 11 Florida school districts. The overview of a large-scale study documents the type and magnitude of change in student-centered teaching, technology tool-based teaching, and student learning that were observed in 440 classrooms over the course of a school year. By employing multiple observations in all schools, document analysis, interviews, and teacher inquiry, an account of the conditions, processes, and consequences (Hall, 1995) of laptop computing was generated. Based on the analysis of data, laptop computing had a positive impact across districts, particularly in regard to changes in teaching practices. Increases in student achievement were also demonstrated across districts. This study calls attention to systemic issues associated with successful laptop implementation and provides implications for statewide laptop programs.
Tourism versus spatial order: mutual relations
Authors: Meyer Beata
Published: February 2012

The relation between tourism and the spatial environment is characterized by mutual interaction. The proliferation of tourism and massive tourism development intensifies its impact on the spatial environment, yet the focus is usually placed on environmental degradation and the resulting distortion of spatial order. Concurrently, the significance of the spatial environment, and spatial order in particular, as one of the determinants of tourism development is understated. On a theoretical plane the relation seems obvious, yet once the practical dimension is considered, it becomes at least debatable.
Thermal Regeneration Model for Spent Montmorillonite Sorbent
Authors: Kostjukovs J. , Sarceviča I. , Actiņš A.
Published: February 2012

Thermal Regeneration Model for Spent Montmorillonite Sorbent

The regeneration possibilities of montmorillonite after repeated heating in the temperature range of 300 °C - 450 °C were investigated. A simple technique for thermal regeneration of spent montmorillonite sorbent was developed. Powder X-ray diffraction (PXRD), thermogravimetry/differential thermal analysis (TG/DTA), wavelength dispersion X-ray fluorescence spectrometry (WDXRF) and visible light spectrometry were employed for sample characterization. Heating at 300 °C allowed successful repeating of regeneration, at which the montmorillonite structure could be restored after several heating cycles. However, regeneration at about 450 °C resulted only in partial regeneration of montmorillonite structure. After three regeneration cycles at 450 °C the pseudo-illitization was irreversible.
Effects of intrathecal baclofen therapy on motor and cognitive functions in a rat model of cerebral palsy
Authors: Nomura Sadahiro , Kagawa Yoshiteru , Kida Hiroyuki , Maruta Yuichi , Imoto Hirochika , Fujii Masami , Suzuki Michiyasu
Published: February 2012

Object

Cerebral palsy (CP) arises in the early stages of brain development and manifests as spastic paresis that is often associated with cognitive dysfunction. Available CP treatments are aimed at the management of spasticity and include botulinum toxin administration, selective dorsal rhizotomy, and intrathecal baclofen (ITB). In this study, the authors investigated whether the management of spasticity with ITB therapy affected motor function and whether the release of spasticity was associated with an improvement in intellectual function.

Methods

Newborn Sprague-Dawley rats were divided into the following groups: control, CP model, and CP model with ITB therapy. For the CP model, postnatal Day 7 (P7) rats were exposed to hypoxic conditions (8% O2) for 150 minutes after ligation of the right common carotid artery. In the groups receiving ITB therapy, a spinal catheter was connected to an osmotic pump filled with baclofen and placed in the spinal subarachnoid space on P21 in the early group and on P35 in the late group. A daily dose of 12 μg of baclofen was continuously administered until P49, resulting in 28 days of therapy in the early group and 14 days in the late group. Changes in spasticity in the CP and CP with ITB treatment groups were confirmed by assessing the motor evoked potential in the plantar muscle.

Results

In the CP group, the time required to complete a beam-walking test on P49 was significantly longer than that in the control and ITB treatment groups (4.15 ± 0.60 vs 2.10 ± 0.18 and 2.22 ± 0.22 seconds, respectively). Results of the beam-walking test are expressed as the mean ± SD. Radial arm maze performance on P49 indicated that spatial reference memory had significantly deteriorated in the CP group compared with controls (2.33 ± 0.87 vs 0.86 ± 0.90 points); moreover, working memory was also negatively affected by CP (0.78 ± 1.09 vs 0.14 ± 0.38 points). Results of the memory tests are expressed as the mean ± SE. These memory functions did not recover after ITB treatment.

Conclusions

Management of spasticity with ITB therapy improved the walking ability in the rat CP model. Intrathecal baclofen therapy—which reduces harmful sensory and motor stimulations caused by spasticity to more optimal levels—contributed to motor function recovery; however, it had no effect on intellectual recovery as assessed by memory performance in the rat CP model.
Comparison of outcomes following decompressive craniectomy in children with accidental and nonaccidental blunt cranial trauma
Authors: Oluigbo Chima O. , Wilkinson C. Corbett , Stence Nicholas V. , Fenton Laura Z. , McNatt Sean A. , Handler Michael H.
Published: February 2012

Object

The goal of this study was to compare clinical outcomes following decompressive craniectomy performed for intracranial hypertension in children with nonaccidental, blunt cranial trauma with outcomes of decompressive craniectomy in children injured by other mechanisms.

Methods

All children in a prospectively acquired database of trauma admissions who underwent decompressive craniectomy over a 9-year span, beginning January 1, 2000, are the basis for this study. Clinical records and neuroimaging studies were systematically reviewed.

Results

Thirty-seven children met the inclusion criteria. Nonaccidental head trauma was the most common mechanism of injury (38%). The mortality rate in patients with abusive brain injury (35.7%) was significantly higher (p < 0.05) than in patients with other causes of traumatic brain injury (4.3%). Children with inflicted head injuries had a 12-fold increase in the odds of death and 3-fold increase in the odds of a poor outcome (King's Outcome Scale for Closed Head Injury score of 1, 2, or 3).

Conclusions

Children with nonaccidental blunt cranial trauma have significantly higher mortality following decompressive craniectomy than do children with other mechanisms of injury. This understanding can be interpreted to mean either that the threshold for decompression should be lower in children with nonaccidental closed head injury or that decompression is unlikely to alter the path to a fatal outcome. If decompressive craniectomy is to be effective in reducing mortality in the setting of nonaccidental blunt cranial trauma, it should be done quite early.
Closure of meningomyelocele defects using acellular dermal matrix
Authors: Hill Sean M. , Elwood Eric T. , Lin Julian
Published: February 2012

Spina bifida is the most common birth defect of the CNS, with meningomyelocele observed in 1 in 800 to 1000 infants. A single reliable method of providing adequate soft-tissue coverage (skin, but also including subcutaneous fat, fascia, and muscle) of the meningomyelocele defect while preventing dehiscence and infection has yet to be defined. This study reviews a case series of 3 patients with large meningomyeloceles treated by a single neurosurgeon /plastic surgeon team at a single institution. Following repair of the neural elements (both dura and neural placode), soft-tissue coverage (skin, but also subcutaneous tissue and fascia) was achieved using acellular dermal matrix over the neural elements, repaired with sutures, and covered with skin flaps. In this series of 3 patients, stable coverage was achieved in all patients. One patient experienced minor wound dehiscence treated with debridement and primary closure with simple relaxing incisions. This series demonstrates that the usage of acellular dermal matrix provides a stable soft-tissue coverage for large meningomyelocele defects in an easily reproducible operation preserving local soft tissue (muscle, fascia) for potential salvage operations or revisions (such as for scoliosis) as well as providing a less demanding operation on the fragile physiology of the neonate.
Performance analysis of winter activity protection headgear for young children
Authors: Hoshizaki Blaine , Vassilyadi Michael , Post Andrew , Oeur Anna
Published: February 2012

Object

The purpose of this study was to evaluate how currently used helmets would perform for winter play activities, such as tobogganing. In Canada and northern parts of the US, the advent of winter is followed by an increase in visits to hospital emergency departments by young children presenting with head injuries resulting from winter activities. Sliding, skating, skiing, and snowboarding all involve risks of head injury from situations such as falling on ice or sliding into stationary objects. This study compared the protective characteristics of helmets used by young children (< 7 years of age) participating in winter recreational activities.

Methods

Ice hockey, alpine ski, and bicycling helmets were impacted at 2.0, 4.0, 6.0, and 8.0 m/second at the front and side impact location by using a monorail drop rig.

Results

The results for the front impact showed that the ice hockey helmet protected the child significantly better at 2 and 4 m/second when considering both linear and angular peak acceleration. The bicycle helmet performed significantly better than the other 2 helmets at 8 m/second for the front location and only angularly for the side impacts.

Conclusions

Depending on the impact velocity of the hazard, the type of helmet significantly affected the risk of brain injury.
Development of secondary unilateral coronal suture synostosis with a sagittal suture synostosis in a nonsyndromic patient
Authors: Rangel-Castilla Leonardo , Hwang Steven W. , Jea Andrew , Whitehead William E. , Curry Daniel J. , Luerssen Thomas G. , Dauser Robert C.
Published: February 2012

Multiple-suture synostosis is typically associated with syndromic craniosynostosis but has been occasionally reported in large series of nonsyndromic children. The diagnosis of multiple fused sutures usually occurs at the same time, but rarely has the chronological development of a secondary suture synostosis been noted. The development of secondary bicoronal suture synostosis requiring surgical intervention has only been reported, to date, after surgical intervention and is hypothesized to arise from a disruption of inhibitory factors from the dura. The disinhibition of these factors permits the sutures to then fuse at an early stage. The authors report on a patient who developed secondary unilateral coronal synostosis after the diagnosis of an isolated sagittal synostosis. The secondary synostosis was identified at the time of the initial surgical intervention and ultimately required a second procedure of a frontoorbital advancement.

The clinical appearance of this phenomenon may be subtle, and surgeons should monitor for the presence of secondary synostosis during surgery as it may require intervention. Failure to identify the secondary synostosis may necessitate another surgery or result in a poor cosmetic outcome. The authors recommend close clinical follow-up for the short term in patients with isolated sagittal synostosis.
Application of neuromuscular blockade and intraoperative 3D imaging in the reduction of basilar invagination
Authors: Dahdaleh Nader S. , Dlouhy Brian J. , Menezes Arnold H.
Published: February 2012

Object

The treatment of basilar invagination in the pediatric age group is dependent on the possibility of preoperative reduction. Reducible lesions obviate a ventral decompression and require a dorsal-only approach for stabilization with or without a suboccipital decompression.

Methods

The authors describe a technique of intraoperative reduction of basilar invagination with the use of general anesthesia and neuromuscular blockade in the presence of crown halo traction. Using the O-arm device, a 3D CT scan is generated in the sagittal plane to demonstrate the reduction intraoperatively. This technique was successful in 6 pediatric patients with basilar invagination.

Results

The average age of the patients was 10.8 years, and they were followed for a mean period of 8.5 months. The patients had mild basilar invagination or partial reduction in extension on preoperative MR imaging. Intraoperative reduction was demonstrated in all patients by using the reported technique with intraoperative CT. All patients underwent occipitocervical fusion, and all but one underwent a suboccipital decompression. There were no complications related to the operation, and all but one reported improvement of symptoms on the last postoperative visit.

Conclusions

Intraoperative reduction performed using neuromuscular blockade and intraoperative traction is an effective method for further reduction of basilar invagination in the pediatric age group. This is the first reported application of intraoperative CT imaging performed using the O-arm device in craniocervical surgery in which successful reduction is demonstrated in detail.
Linking Single Domain Antibodies that Recognize Different Epitopes on the Same Target
Authors: Glaven Richard H. , Anderson George P. , Zabetakis Dan , Liu Jinny L. , Long Nina C. , Goldman Ellen R.
Published: February 2012

Single domain antibodies (sdAb) are the recombinantly expressed variable regions from the heavy-chain-only antibodies found in camelids and sharks. SdAb are able to bind antigens with high affinity, and most are capable of refolding after heat or chemical denaturation to bind antigen again. Starting with our previously isolated ricin binding sdAb determined to bind to four non-overlapping epitopes, we constructed a series of sdAb pairs, which were genetically linked through peptides of different length. We designed the series so that the sdAb are linked in both orientations with respect to the joining peptide. We confirmed that each of the sdAb in the constructs was able to bind to the ricin target, and have evidence that they are both binding ricin simultaneously. Through this work we determined that the order of genetically linked sdAb seems more important than the linker length. The genetically linked sdAb allowed for improved ricin detection with better limits of detection than the best anti-ricin monoclonal we evaluated, however they were not able to refold as well as unlinked component sdAb.
Nanoscopic and Photonic Ultrastructural Characterization of Two Distinct Insulin Amyloid States
Authors: Psonka-Antonczyk Katarzyna Maria , Duboisset Julien , Stokke Bjørn Torger , Zako Tamotsu , Kobayashi Takahiro , Maeda Mizuo , Nyström Sofie , Mason Jeff , Hammarström Per , Nilsson K. Peter R. , Lindgren Mikael
Published: February 2012

Two different conformational isoforms or amyloid strains of insulin with different cytotoxic capacity have been described previously. Herein these filamentous and fibrillar amyloid states of insulin were investigated using biophysical and spectroscopic techniques in combination with luminescent conjugated oligothiophenes (LCO). This new class of fluorescent probes has a well defined molecular structure with a distinct number of thiophene units that can adopt different dihedral angles depending on its binding site to an amyloid structure. Based on data from surface charge, hydrophobicity, fluorescence spectroscopy and imaging, along with atomic force microscopy (AFM), we deduce the ultrastructure and fluorescent properties of LCO stained insulin fibrils and filaments. Combined total internal reflection fluorescence microscopy (TIRFM) and AFM revealed rigid linear fibrous assemblies of fibrils whereas filaments showed a short curvilinear morphology which assemble into cloudy deposits. All studied LCOs bound to the filaments afforded more blue-shifted excitation and emission spectra in contrast to those corresponding to the fibril indicating a different LCO binding site, which was also supported by less efficient hydrophobic probe binding. Taken together, the multi-tool approach used here indicates the power of ultrastructure identification applying AFM together with LCO fluorescence interrogation, including TIRFM, to resolve structural differences between amyloid states.
CASPER: Embedding Power Estimation and Hardware-Controlled Power Management in a Cycle-Accurate Micro-Architecture Simulation Platform for Many-Core Multi-Threading Heterogeneous Processors
Authors: Datta Kushal , Mukherjee Arindam , Cao Guangyi , Tenneti Rohith , Vijendra Kumar Lakshmi Vinay , Ravindran Arun , Joshi Bharat S.
Published: February 2012

Despite the promising performance improvement observed in emerging many-core architectures in high performance processors, high power consumption prohibitively affects their use and marketability in the low-energy sectors, such as embedded processors, network processors and application specific instruction processors (ASIPs). While most chip architects design power-efficient processors by finding an optimal power-performance balance in their design, some use sophisticated on-chip autonomous power management units, which dynamically reduce the voltage or frequencies of idle cores and hence extend battery life and reduce operating costs. For large scale designs of many-core processors, a holistic approach integrating both these techniques at different levels of abstraction can potentially achieve maximal power savings. In this paper we present CASPER, a robust instruction trace driven cycle-accurate many-core multi-threading micro-architecture simulation platform where we have incorporated power estimation models of a wide variety of tunable many-core micro-architectural design parameters, thus enabling processor architects to explore a sufficiently large design space and achieve power-efficient designs. Additionally CASPER is designed to accommodate cycle-accurate models of hardware controlled power management units, enabling architects to experiment with and evaluate different autonomous power-saving mechanisms to study the run-time power-performance trade-offs in embedded many-core processors. We have implemented two such techniques in CASPER–Chipwide Dynamic Voltage and Frequency Scaling, and Performance Aware Core-Specific Frequency Scaling, which show average power savings of 35.9% and 26.2% on a baseline 4-core SPARC based architecture respectively. This power saving data accounts for the power consumption of the power management units themselves. The CASPER simulation platform also provides users with complete support of SPARCV9 instruction set enabling them to run a full operating system software stack, and hence a wide variety of benchmarking applications.
Aligned Layers of Silver Nano-Fibers
Authors: Golovin Andrii B. , Stromer Jeremy , Kreminska Liubov
Published: February 2012

We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.
The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD) Metals and the Influential Factors
Authors: Kwan Charles C. F. , Wang Zhirui
Published: February 2012

A deeper understanding of the mechanical behavior of ultra-fine (UF) and nanocrystalline (NC) grained metals is necessary with the growing interest in using UF and NC grained metals for structural applications. The cyclic deformation response and behavior of UF and NC grained metals is one aspect that has been gaining momentum as a major research topic for the past ten years. Severe Plastic Deformation (SPD) materials are often in the spotlight for cyclic deformation studies as they are usually in the form of bulk work pieces and have UF and NC grains. Some well known techniques in the category of SPD processing are High Pressure Torsion (HPT), Equal Channel Angular Pressing (ECAP), and Accumulative Roll-Bonding (ARB). In this report, the literature on the cyclic deformation response and behavior of SPDed metals will be reviewed. The cyclic response of such materials is found to range from cyclic hardening to cyclic softening depending on various factors. Specifically, for SPDed UF grained metals, their behavior has often been associated with the observation of grain coarsening during cycling. Consequently, the many factors that affect the cyclic deformation response of SPDed metals can be summarized into three major aspects: (1) the microstructure stability; (2) the limitation of the cyclic lifespan; and lastly (3) the imposed plastic strain amplitude.
Effects of the Cyclin-Dependent Kinase 10 (CDK10) on the Tamoxifen Sensitivity of Keloid Samples
Authors: Liu Ying , Xiao Zhibo , Yang Daping , Ren Lihong , Liu Guofeng , Yang Lin
Published: February 2012

Cyclin-dependent kinase 10 (CDK10) is a cell cycle regulating protein kinase, which has just been discriminated in recent years. In this paper, mRNA and protein expression of CDK10 were first investigated by a comparative study between 23 human keloid tissue samples and their adjacent normal skin. To further address its potential as a therapeutic target in the treatment of keloid, a plasmid expressing the CDK10 gene was transfected into keloid fibroblast. The effects on tamoxifen-induced apoptosis were then investigated using Western blot assay and flow cytometry. Results showed that there is a generally down-regulated expression of CDK10 in keloid compared to normal skin samples. Transfection with the recombinant CDK10 plasmid significantly decreased the viability of cells and increased the apoptosis rates. Tamoxifen sensitivity in keloid fibroblasts was observed after treatment with the recombinant CDK10 plasmid. The results suggested that CDK10 may play an important role in enhancement of tamoxifen efficiency, and its expression may have a synergistic effect on keloid treatments.