bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomimetic materials
Authors: Vincent Julian F.V.
Published: November 2008

I’ve long been suspicious about attempts to see energy as the overwhelmingly central item setting both options and criteria for design in nature. Indeed, when I tried to create a conceptual framework for teaching biology to college students, I ended up putting energy distinctly second to information. Where energy rules, one can find some analog of voltage potential. But in nature, who eats whom boils down to the design and operation of one’s particular teeth and other equipment. I once set up an electrical analog of an ecosystem, but it gave an unreasonable picture until I addedad hocdiodes to keep the trees from eating the caterpillars at night and other such misbehavior.(Steve Vogel, Duke University, 2007)

In materials processing, Nature replaces the massive use of energy (for example high temperatures or harsh chemical reactions) with the use of information (which equates with structure at all levels, molecule to ecosystem). Indeed, most of the exceptional functionality of biological materials is due to their complex structure, driven by their chemical composition and morphology derived from DNA. It is here that the most important aspect of biomimetics emerges, and it has the power to redesign engineering.
Light manipulation in a marine diatom
Authors: Noyes Joseph , Sumper Manfred , Vukusic Pete
Published: November 2008

Diatoms are well known for the intricately patterned nanostructure of their silica-based cell walls. To date, the optical properties of diatom cell-wall ultrastructures have largely gone uncharacterized experimentally. Here we report the results of a detailed experimental investigation of the way in which light interacts with the ultrastructure of a representative centric diatom species,Coscinodiscus wailesii. Light interaction both with individual valves and whole bivalves of the diatomC. wailesiiwas measured. Significant sixfold symmetric diffraction through the valve ultrastructure was observed in transmission and quantified to efficiencies that were found to be strongly wavelength dependent; approximately 80% for red, 30% for green, and 20% for blue light. While these results may potentially offer insight into the role of periodic nanostructure in diatom selection, they are also important for consideration in the design of biomimetic optics-based diatom applications.
Compressive testing of single yeast cells in liquid environment using a nanoindentation system
Authors: Arfsten J. , Bradtmöller C. , Kampen I. , Kwade A.
Published: November 2008

Due to their versatility and accuracy, nanoindentation systems are increasingly used for the characterization of micron-sized particles. Single microbial cells (e.g., yeast cells) can be regarded as micron-sized, liquid-filled biological particles. Applying a nanoindentation system for the compressive testing of those cells offers many options, such as testing in liquid environment. However, diverse experimental problems have to be resolved, especially the visualization of the cells in liquid and the alignment of the surfaces between which the cell is compressed. Single yeast cells were tested using a nanoindenter equipped with a flat punch tip. The deformation behavior of the cells during loading as well as the shape recovery behavior during unloading was investigated. A bursting force was determined as the cell wall was failing at higher deformations. Moreover, the influence of the compression speed on the cell mechanical behavior was characterized.
Enzymatic processing of amelogenin during continuous crystallization of apatite
Authors: Uskoković V. , Kim M-K. , Li W. , Habelitz S.
Published: November 2008

Dental enamel forms through a protein-controlled mineralization and enzymatic degradation process with a nanoscale precision that new engineering technologies may be able to mimic. Recombinant full-length human amelogenin (rH174) and a matrix-metalloprotease (MMP-20) were used in a pH-stat titration system that enabled a continuous supply of calcium and phosphate ions over several days, mimicking the initial stages of matrix processing and crystallization in enamel in vitro. Effects on the self-assembly and crystal growth from a saturated aqueous solution containing 0.4 mg/mL rH174 and MMP-20 with the weight ratio of 1:1000 with respect to rH174 were investigated. A transition from nanospheres to fibrous amelogenin assemblies was facilitated under conditions that involved interaction between rH174 and its proteolytic cleavage products. Despite continuous titration, the levels of calcium exhibited a consistent trend of decreasing, thereby indicating a possible role in protein self-assembly. This study suggests that mimicking enamel formation in vitro requires the synergy between the aspects of matrix self-assembly, proteolysis, and crystallization.
Biomimetic nanocoating promotes osteoblast cell adhesion on biomedical implants
Authors: Likibi Fidele , Jiang Bingbing , Li Bingyun
Published: November 2008

Implantation of dental and orthopaedic devices is affected by delayed or weak implant-bone integration and inadequate new bone formation. Innovative approaches have been sought to enhance implant-bone interaction to achieve rapid osseointegration. The aim of this study was to develop biomimetic polypeptide nanocoatings and to evaluate cell adhesion, proliferation, morphology, and biocompatibility of polypeptide nanocoatings on implant surfaces. A recently developed nanotechnology, i.e., electrostatic self-assembly, was applied to build polypeptide nanocoatings on implant models, i.e., stainless steel discs. Our in vitro tests using human osteoblast cells revealed that substantially more (one order magnitude higher) osteoblast cells were attached to polypeptide-coated, stainless steel discs than to uncoated discs within the first few hours of contact. The developed biomimetic nanocoatings may have great potential for dental and orthopaedic applications.
Growth of epitaxial films of sodium potassium tantalate and niobate on single-crystal lanthanum aluminate [100] substrates
Authors: Thomas George H. , Specht Eliot D. , Larese John Z. , Xue Ziling B. , Beach David B.
Published: November 2008

Epitaxial films of sodium potassium tantalate (Na0.5K0.5TaO3, NKT) and sodium potassium niobate (Na0.5K0.5NbO3, NKN) were grown on single-crystal lanthanum aluminate (LAO) (100) (indexed as a pseudo-cubic unit cell) substrates via an all-alkoxide solution (methoxyethoxide complexes in 2-methoxyethanol) deposition route for the first time. X-ray diffraction studies indicated that the onset of crystallization in powders formed from hydrolyzed gel samples was 550 °C. 13C nuclear magnetic resonance studies of solutions of methoxyethoxide complexes indicated that mixed-metal species were formed, consistent with the low crystallization temperatures observed. Thermal gravimetric analysis with simultaneous mass spectrometry showed the facile loss of the ligand (methoxyethoxide) at temperatures below 400 °C. Crystalline films were obtained at temperatures as low as 650 °C when annealed in air. θ-2θ x-ray diffraction patterns revealed that the films possessed c-axis alignment in that only (h00) reflections were observed. Pole-figures about the NKT or NKN (220) reflection indicated a single in-plane, cube-on-cube epitaxy. The quality of the films was estimated via ω (out-of-plane) and φ (in-plane) scans and full-widths at half-maximum (FWHMs) were found to be reasonably narrow (∼1°), considering the lattice mismatch between the films and the substrate.
Strain-controlled bulge test
Authors: Alaca B. Erdem , Toga K. Bugra , Akar Orhan , Akin Tayfun
Published: November 2008

A closed-loop approach is adopted to implement strain rate control during the bulge test. Due to the difficulty of measuring strains directly, the technique is based on the conversion of displacement measurements to the corresponding strains using the plane-strain formulation. The necessary temporal evolution of the midpoint displacement of a rectangular diaphragm is derived under the condition of constant strain rate and is imposed as a control criterion. The technique is demonstrated on 500-nm-thick Au diaphragms by applying strain rates ranging from 2 × 10−6 to 2 × 10−4 s–1. By measuring the corresponding yield strength values, a strain rate sensitivity of 0.11 is obtained, which is close to what was previously reported on similar specimens using the microbending test.
Synthesis of poly-2-hydroxyethyl methacrylate–montmorillonite nanocomposite via in situ atom transfer radical polymerization
Authors: Oral Ayhan , Shahwan Talal , Güler Çetin
Published: November 2008

The poly-2-hyroxyethyl methacrylate (PHEMA)/clay nanocomposite was synthesized by in situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. To produce organically modified montmorillonite (MMT) that has ATRP initiator moiety, a new catalyst that consists of quaternary ammonium salt moiety and an initiator moiety was synthesized. This initiator was intercalated into the interlayer spacing of the MMT. The polymerization reaction was carried out in a mixed solvent system consisting of methyl ethyl ketone and 1-propanol at 50 °C, using the initiator that has been already synthesized with a copper bromide catalyst. The 2, 2′-bipyridyl (bpy) complex was used as ligand. The products were characterized via Fourier transform infrared, nuclear magnetic resonance (1H NMR, 12C NMR), transmission electron microscopy, x-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.
Transmission electron microscopic studies on growth mechanism of YBa2Cu3O7−y films formed by advanced trifluoroacetates metalorganic deposition process
Authors: Matsuda J. , Nakaoka K. , Izumi T. , Yamada Y. , Shiohara Y.
Published: November 2008

Microstructure evolution of YBa2Cu3O7−y (YBCO) films during the two heat-treatments in the advanced trifluoroacetates metalorganic deposition (TFA-MOD) process has been investigated by means of transmission electron microscopy. In the calcination process, precursor films including nanopores were formed through the shrinkage of the film after a remarkable increase of the thickness due to the thermal decomposition of metalorganic salts in the starting solution. During the crystallization process, the densification and shrinkage of the film occurred after agglomeration of nanopores and coarsening of unreacted phase particles such as Y2Cu2O5, CuO, and Ba–O–F in the precursor films. The YBCO films were then epitaxially grown with the remaining unreacted phase particles in the film, finally pores were generated again by a reaction of these unreacted particles to form YBCO accompanied by the volume reduction. It is important to control the densification of precursor films and coarsening of the unreacted phase particles in the crystallization process, to fabricate YBCO final films with fine crystallinity and high critical current values.
Initial formation mechanisms of (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates
Authors: Lee K.H. , Lee J.Y. , Jeon H.C. , Kang T.W. , Kwon H.Y. , Kim T.W.
Published: November 2008

The (Ga1−xMnx)N nanorods were grown on Al2O3 (0001) substrates by using rf-associated molecular beam epitaxy. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area diffraction pattern (SADP) results showed that the (Ga1−xMnx)N nanorods had (0001) preferential orientations. XRD patterns showed that the (Ga1−xMnx)N nanorods contained a small number of grains with different preferred orientations. High-resolution TEM (HRTEM) images showed that the (Ga1−xMnx)N nanorods consisted of different preferentially oriented grains. The initial formation mechanisms for the (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates are described on the basis of the XRD, the TEM, the SADP, and the HRTEM results.
Electric field-induced crack growth and domain-structure evolution for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3) O3–28%PbTiO3 ferroelectric single crystals
Authors: Fang F. , Yang W. , Zhang F.C. , Qing H.
Published: November 2008

In situ observation of the electrically induced crack growth and domain-structure evolution is carried out for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3)O3–28% PbTiO3 (PMN–PT 72/28) ferroelectric single crystals under static (poling) and alternating electric fields. On the same poling electric field, domains are in the stable engineered domain state where four equivalent polarization variants coexist for [100]-oriented single crystal, while parallel lines representing the 71° domain boundaries appear for [101]-oriented one. Under the same cyclic electric field, the [100]-oriented single crystal shows much higher crack propagation resistance than that of a [101]-oriented crystal. Apart from the material aspects, such as crystallographic fracture anisotropy and non-180° domain boundary structure, crack boundary condition plays an important role in determining the crack propagation behavior.
Synthesis of spinel iron oxide nanoparticle/organic hybrid for hyperthermia
Authors: Hayashi Koichiro , Shimizu Toshifumi , Asano Hidefumi , Sakamoto Wataru , Yogo Toshinobu
Published: November 2008

Size-controlled spinel iron oxide (SIO) nanoparticle/organic hybrid was synthesized in situ from iron (III) allylacetylacetonate (IAA) at around 80 °C. The formation of SIO particles chemically bound with organics was confirmed by infrared and x-ray photoelectron spectroscopy. The sizes of SIO nanoparticles in the hybrids were monodispersed and ranged from 7 to 23 nm under controlled hydrolysis conditions. The hybrid including SIO particles of 7.3 nm was superparamagnetic, whereas those dispersed with particles above 11 nm were ferrimagnetic. The specific absorption rate (SAR) value was dependent upon the magnetic properties of the hybrid at 100 Oe. The SAR was 15.2 W g−1in a 230 kHz alternating magnetic field and 100 Oe when the crystallite size of SIO particle in the hybrid was 16 nm. The temperatures of agars dispersed with hybrid powders of 5 and 8 mg ml−1reached the optimum temperature (42 °C) for 17 and 8 min, respectively. The increase in temperature was controlled in terms of the strength of magnetic field. The simulation of heat transfer in the agar phantom model revealed that the suitable temperature distribution for therapy was attained from 15 to 20 min at 230 kHz and 100 Oe.
Limiting behavior of delayed sums under a non-identically distribution setup
Authors: Pingyan Chen
Published: November 2008

We present an accurate description the limiting behavior of delayed sums under a non-identically distribution setup, and deduce Chover-type laws of the iterated logarithm for them. These complement and extend the results of Vasudeva and Divanji (Theory of Probability and its Applications, 37 (1992), 534-542).
Nutrient and phytoplankton biomass in the Amazon River shelf waters
Authors: Santos Maria L.S. , Muniz Kátia , Barros-Neto Benício , Araujo Moacyr
Published: November 2008

The Amazon River estuary is notable at the Amazon Continental Shelf, where the presence of the large amount of water originating from the Amazon during the river's falling discharge period was made evident by the low salinity values and high nutrient levels. Even so, the presence of oceanic waters in the shelf area was significant. Dissolved organic nitrogen was the predominant species of the nitrogen cycle phases, followed by total particulate nitrogen, nitrate, ammonium and nitrite. The chlorophyll a data in the eutrophic area indicated that there is sufficient nitrogen in the area to withstand productivity, though dissolved inorganic nitrogen removal processes are faster than regeneration or mineralization. The anomalous amounts of inorganic dissolved nitrogen showed more removal than addition. The simulations with the bidimensional MAAC-2D model confirmed that high nutrient waters are displaced northwest-ward (two cores at 2.5ºN-50ºW and 4ºN-51ºW) by the stronger NBC during falling river discharge. During high river flow period these nutrient-rich lenses are distributed around 0.5ºN-48.5ºW as well as along the shallow Amazonian shelf (20m-50m depth, 1ºN-3.5ºN), as a result of the spreading of Amazon freshwater outflow.
Evolução dos isolamentos em doenças transmissíveis: os saberes na prática contemporânea
Authors: Nichiata Lúcia Yasuko Izumi , Gir Elucir , Takahashi Renata Ferreira , Ciosak Suely Itsuko
Published: November 2008

A identificação de novos agentes infecciosos, a crescente expansão de infecções e doenças já conhecidas têm estimulado a revisão das medidas de biossegurança nas atividades profissionais dos trabalhadores da saúde. No presente artigo recuperou-se a evolução dos saberes e práticas dos isolamentos/precauções, o que permitiu resgatar os conceitos e as intervenções que vieram sendo formuladas e implementadas. Desde o início da enfermagem moderna, no século XIX, mantém-se basicamente os mesmos elementos da prática dos isolamentos em doenças transmissíveis, ou seja, destaque à utilização de barreiras mecânicas, químicas e ambientais, fundamentadas nas especificidades inerentes aos elementos da cadeia do processo infeccioso.
Ensino de enfermagem em nível médio: utilização de estratégia facilitadora com material reciclável
Authors: Tobase Lucia , Takahashi Regina Toshie
Published: November 2008

Este estudo teve como objetivo desenvolver estratégias facilitadoras no processo de ensino e aprendizagem, utilizando-se de materiais recicláveis na construção de estruturas e órgãos anatômicos. Foi desenvolvido na disciplina Enfermagem Médico-Cirúrgica, a 31 alunos no curso de nível médio para formação do Auxiliar de Enfermagem. Após leituras de referências bibliográficas relacionadas à Anatomia, Fisiologia e Patologias mais comuns dos diversos sistemas do corpo humano, os alunos selecionaram os materiais recicláveis disponíveis para a confecção das principais estruturas anatômicas, o que possibilitou a visualização das alterações morfológicas decorrentes das afecções, facilitando assim a compreensão das patologias. As estratégias utilizadas favoreceram a aquisição de conhecimentos ao se projetarem em algo concreto, resultado da troca de sugestões e experiências entre os estudantes, favorecido pelo trabalho em grupo.
Percepção de crianças hospitalizadas sobre realização de exames
Authors: Soares Virgínia Virgilio , Vieira Luiza Jane Eyre de Souza
Published: November 2008

O estudo teve como objetivo identificar a percepção da criança hospitalizada, em idade escolar, sobre a realização de exames. Foi utilizada a pesquisa de natureza descritiva, predominando a investigação de caráter qualitativo. Os resultados revelaram que as crianças cooperam com os exames apesar do medo. O medo foi relacionado ao temor da dor física, de ser machucado, e ainda, do desconhecido. Considera-se que a criança percebe a realização do exame como parte do seu tratamento e gostaria de receber explicações sobre o procedimento.
Educação para a leitura crítica da mídia, democracia radical e a reconstrução da educação
Authors: Kellner Douglas , Share Jeff
Published: November 2008

Neste artigo, exploram-se as bases teóricas da educação para a leitura crítica da mídia e analisam-se diferentes abordagens a serem empregadas em seu ensino. Ao combinar estudos culturais com pedagogia crítica, defendemos uma discussão em defesa da alfabetização crítica da mídia, que vise a ampliar a noção de alfabetização, incluindo uma ampla variedade de formas de cultura midiática, informações e tecnologias da comunicação e novos meios de comunicação, além de aprofundar o potencial da alfabetização para analisar criticamente relações entre os meios de comunicação e as audiências, a informação e o poder. Utiliza-se uma abordagem multiperspectivista, tratando de questões de gênero, raça, classe e poder, para explorar as inter-relações entre a alfabetização midiática, os estudos culturais e a pedagogia crítica. Nossa versão de alfabetização digital integra análise e produção e visa a dar poderes aos alunos para que tenham plena participação em sua sociedade. Assim, essa visão promove a democracia radical e a justiça social.
Infância, mídias e aprendizagem: autodidaxia e colaboração
Authors: Belloni Maria Luiza , Gomes Nilza Godoy
Published: November 2008

A interação entre pares e com adultos, em situações favoráveis e inovadoras de aprendizagem e com uso pedagógico apropriado das Tecnologias de Informação e Comunicação (TIC), pode levar as crianças a desenvolverem comportamentos colaborativos e autônomos de aprendizagem, benéficos para seu desenvolvimento intelectual e sócio-afetivo. Nossa hipótese é de que ambientes de aprendizagem computacionais tendem a ser eficazes para esta aprendizagem, pois possibilitam a mediação entre o sujeito e o objeto do conhecimento a ser construído, conforme sugerem os aportes das teorias construtivista e sócio-interacionista. O objetivo de nossa pesquisa é compreender como ocorrem estes "novos modos de aprender" que já vêm se desenvolvendo, à revelia da escola e, de modo geral, ignorados por professores e especialistas, desde que as crianças começaram a aceder à televisão e aos videogames e se amplificaram e complexificaram com o acesso e uso lúdico do computador e da internet.
As tecnologias na política nacional de formação de professores a distância: entre a expansão e a redução
Authors: Barreto Raquel Goulart
Published: November 2008

Este artigo foi produzido a partir de três pontos de entrada: (1) recontextualização; (2) expansão e redução e (3) tutores: concepção e condições de trabalho. Com base neles, discute a inscrição das tecnologias na configuração da política nacional de formação de professores a distância, focalizando os pressupostos e as implicações das formulações que a sustentam.
Promoção à saúde e empoderamento: uma reflexão a partir das perspectivas crítico-social pós-estruturalista
Authors: Carvalho Sérgio Resende , Gastaldo Denise
Published: November 2008

Neste trabalho, descrevemos o arcabouço teórico e as estratégias centrais da Promoção à Saúde, seguidos de uma análise crítica tanto intra como extra-paradigmática ao ideário do referido movimento. A partir de uma perspectiva intra-paradigmática, privilegiamos o enfoque ao qual se filia a Promoção à Saúde, as teorias crítico-sociais, para analisar um dos seus conceitos estruturantes - o conceito de empoderamento -, explorando seu potencial para a transformação das práticas comunitárias e profissionais em saúde. A seguir, refletimos sobre a Promoção à Saúde a partir de uma perspectiva extra-paradigmática, buscando nas teorias pós-estruturalistas novas possibilidades analíticas para entender as relações de poder que se estabelecem a partir das práticas e políticas de Promoção à Saúde. Ao longo deste artigo, articulamos os princípios teóricos explorados a questões contextuais e a debates atuais na área da saúde no Brasil.
Autonomia como categoria central no conceito de promoção de saúde
Authors: Fleury-Teixeira Paulo , Vaz Fernando Antônio Camargo , Campos Francisco Carlos Cardoso de , Álvares Juliana , Aguiar Raphael Augusto Teixeira , Oliveira Vinícius de Araújo
Published: November 2008

Este artigo expõe os conceitos centrais do estudo de múltiplos casos: "Promoção de Saúde na Atenção Básica". O estudo foi conduzido pelo Nescon-UFMG em 2005 em doze experiências de promoção da saúde realizadas por equipes do Programa de Saúde da Família (PSF) em diversas regiões do Brasil. Após revisão teórica e pesquisa de campo, a definição de promoção da saúde adotada foi a atuação para a melhoria da saúde, anterior e independente a qualquer patologia ou agravo, ampliando-se o controle das pessoas sobre a própria saúde. Também concluímos que a ampliação da autonomia, vista como ampliação das capacidades e possibilidades de escolha das pessoas, é a categoria central e o critério definidor da atuação em promoção de saúde.
Metodologias ativas de ensino-aprendizagem na formação profissional em saúde: debates atuais
Authors: Mitre Sandra Minardi , Siqueira-Batista Rodrigo , Girardi-de-Mendonça José Márcio , Morais-Pinto Neila Maria de , Meirelles Cynthia de Almeida Brandão , Pinto-Porto Cláudia , Moreira Tânia , Hoffmann Leandro Marcial Amaral
Published: November 2008

As vertiginosas transformações das sociedades contemporâneas têm colocado em questão, de modo cada vez mais incisivo, os aspectos relativos à formação profissional. Este debate ganha contornos próprios no trabalho em saúde, na medida em que a indissociabilidade entre teoria e prática, o desenvolvimento de uma visão integral do homem e a ampliação da concepção de cuidado tornam-se prementes para o adequado desempenho laboral. Com base nestas considerações, o objetivo do presente artigo é discutir as principais transformações metodológicas no processo de formação dos profissionais de saúde, com ênfase na apreciação das metodologias ativas de ensino-aprendizagem.
Reflexões sobre os objetos e os ambientes físicos de ensino e pesquisa em saúde
Authors: Grossman Elio , Araújo-Jorge Tania Cremonini de , Araujo Inesita Soares de
Published: November 2008

O artigo traz um novo olhar sobre os objetos e ambientes físicos destinados às atividades de ensino e pesquisa em saúde. Aponta questões sobre a comunicação entre os designers e as pessoas que utilizam seus projetos. Pergunta sobre as formas de contribuição do designer para a transformação positiva do estado de espírito dos usuários de ambientes destinados ao ensino e à saúde, levando em conta as reações ou sentimentos das pessoas perante os produtos e os ambientes, em especial manifestações de alegria e bem-estar. E apresenta a edição piloto de um instrumento diferenciado de sensibilização e levantamento de dados, no formato de oficina de trabalho, denominada Espaço, Criação e Alegria.
Critical analysis of PCDD/F emissions from anaerobic digestion
Authors: Rada E. C. , Ragazzi M.
Published: November 2008

This paper concerns a particular aspect of anaerobic digestion, that is the emission of PCDD/F in different scenarios where this biological process is present. The considered scenarios are: anaerobic digestion of automatically sorted Municipal Solid Waste, source separated organic fraction of Municipal Solid Waste treated in an anaerobic digester, anaerobic process developed in a Municipal Solid Waste sanitary landfill. Not always the emissions taken into account are related to combustion of biogas from anaerobic digestion: the loss of biogas from a landfill causes an uncontrolled emission of PCDD/F. The paper is completed with an analysis of the role of anaerobic digestion in PCDD/F inventories and health risk considerations. Indeed the most detailed inventories offer emission factors useful for a deep understanding of the phenomenon of PCDD/F release into the atmosphere. Concerning health risk, some suggestions in order to decrease it are proposed.
Anaerobic digestion of residues from production and refining of vegetable oils as an alternative to conventional solutions
Authors: Torrijos M. , Thalla Arun Kumar , Sousbie P. , Bosque F. , Delgenès J. P.
Published: November 2008

The purpose of this work was to study the anaerobic digestion of by-products generated during the production and refining of oil with the objective of proposing an alternative solution (methanisation) to the conventional solutions while reducing the energy consumption of fossil origin on refinery sites. The production of sunflower oil was taken as example. Glycerine from the production of biodiesel was also included in this study. The results show that glycerine has a high potential for methanisation because of its high methane potential (465 ml CH4/g VS) and high metabolization rates (0.42 g VS/g VSS.d). The use of oil cake as substrate for anaerobic digestion is not interesting because it has a low methane potential of 215 ml CH4/g VS only and because it is easily recovered in animal feed. Six residues have quite a high methane potential (465 to 850 ml CH4/g VS) indicating a good potential for anaerobic digestion. However, they contain a mixture of rapidly and slowly biodegradable organic matter and the loading rates must remain quite low (0.03 to 0.09 g VS/g VSS.d) to prevent any accumulation of slowly biodegradable solids in the digesters.
A comprehensive method for organic matter characterization in solid wastes in view of assessing their anaerobic biodegradability
Authors: Buffiere Pierre , Frederic Sylvain , Marty Bruno , Delgenes Jean-Philippe
Published: November 2008

The calculation of the anaerobic biodegradability requires the knowledge of the COD of the organic waste considered. Unfortunately, standard COD measurements are not available for solid wastes. In addition, sample processing generally requires a drying step (for TS and VS assessment for instance). What is shown here is that important amounts of COD might be lost upon drying (around 30% in the case of spent apples). We propose an alternate method based on the separation of the waste in two fractions: water soluble (WS) and non water soluble (NWS, particulate). The two fractions have been characterized individually and both the COD and the biodegradability could be assessed with a greater accuracy. For spent apples, the biodegradability of the NWS fraction is much lower than that of the WS fraction (36.6% vs. 95.2%), and can be well predicted from a previously established model based on the measurement of the cellulose and lignin fractions.
Detection and identification of degradation products of sulfamethoxazole by means of LC/MS and −MSn after ozone treatment
Authors: Abellán M. N. , Gebhardt W. , Schröder H. Fr.
Published: November 2008

The ozonation of the antibiotic sulfamethoxazole has been studied, in order to elucidate the structures of some of the degradation products generated throughout the process. Under the conditions applied, a complete destruction of sulfamethoxazole was achieved after 10 minutes of reaction. The biodegradability of the resulting solution has been also determined, and this parameter undergoes a gradual increase along during the reaction time. The acute toxicity of the reaction mixture, on the contrary, is only decreased during the first 5 minutes of reaction while it increases subsequently. Some of the intermediates resulting during ozonation seem to be more toxic to Daphnia magna than the untreated sulfamethoxazole. The structures of selected degradation products found in the solution are determined and identified. Ozone predominantly attacks sulfamethoxazole via the amine group of the aniline ring in some cases giving rise to nitro-aromatic compounds.
Sink or source? - The effect of hydrology on phosphorus release in the cultivated riverine wetland Spreewald (Germany)
Authors: Gabriel O. , Balla D. , Kalettka T. , Maassen S.
Published: November 2008

The cultivated riverine wetland region Spreewald faces detrimental changes in the hydrological conditions due to a significant discharge reduction. With its dense network of impounded waterways and a forced tendency of sedimentation of soluble reactive phosphorus adsorbed to large amounts of FeOH/FeOOH available from mining water and groundwater discharges the 320 km2 region is favoured to accumulate large amounts of total phosphorus (TR) and thus act as an effective phosphorus sink. The change of conditions strongly challenges this function hereafter. This is especially important because eutrophication of lakes downstream the Spreewald region is controlled by phosphorus. Phosphorus balances at a testfield situated in a polder area typical for the central Spreewald region point out that hydrological and consequently hydraulic conditions are the key factors for the phosphorus sink or source behaviour. This is true for the main processes determine P retention and release at the sediment-surface water transition zone as well as for the dominant phosphorus release and retention pathways: groundwater emissions and sedimentation. In the context of hydrological changes in the Spree river catchment results from point scale and river reach scale point out the need for an adapted water management in the Spreewald region to prevent risk of extended eutrophication tendencies downstream due to forced SRP emissions.
The use of GIS and multi-criteria evaluation (MCE) to identify agricultural land management practices which cause surface water pollution in drinking water supply catchments
Authors: Grayson Richard , Kay Paul , Foulger Miles
Published: November 2008

Diffuse pollution poses a threat to water quality and results in the need for treatment for potable water supplies which can prove costly. Within the Yorkshire region, UK, nitrates, pesticides and water colour present particular treatment problems. Catchment management techniques offer an alternative to ‘end of pipe’ solutions and allow resources to be targeted to the most polluting areas. This project has attempted to identify such areas using GIS based modelling approaches in catchments where water quality data were available. As no model exists to predict water colour a model was created using an MCE method which is capable of predicting colour concentrations at the catchment scale. CatchIS was used to predict pesticide and nitrate N concentrations and was found to be generally capable of reliably predicting nitrate N loads at the catchment scale. The pesticides results did not match the historic data possibly due to problems with the historic pesticide data and temporal and spatially variability in pesticide usage. The use of these models can be extended to predict water quality problems in catchments where water quality data are unavailable and highlight areas of concern.
A Role for von Hippel-Lindau Protein in Pancreatic β-Cell Function
Authors: Puri Sapna , Cano David A. , Hebrok Matthias
Published: November 2008

OBJECTIVE—The Vhlh gene codes for the von Hippel-Lindau protein (VHL), a tumor suppressor that is a key player in the cellular response to oxygen sensing. In humans, a germline mutation in the VHL gene leads to the von Hippel-Lindau disease, a familial syndrome characterized by benign and malignant tumors of the kidney, central nervous system, and pancreas.

RESEARCH DESIGN AND METHODS—We use Cre-lox recombination to eliminate Vhlh in adult mouse pancreatic β-cells. Morphology of mutant islets is assessed by immunofluorescence analysis. To determine the functional state of Vhlh−/− islets, insulin secretion is measured in vivo and in vitro, and quantitative PCR is used to identify changes in gene expression.

RESULTS—Loss of VHL in β-cells leads to a severe glucose-intolerant phenotype in adult animals. Although VHL is not required for β-cell specification and development, it is critical for β-cell function. Insulin production is normal in β-cells lacking VHL; however, insulin secretion in the presence of high concentrations of glucose is impaired. Furthermore, the loss of VHL leads to dysregulation of glycolytic enzymes, pointing to a perturbation of the intracellular energy homeostasis.

CONCLUSIONS—We show that loss of VHL in β-cells leads to defects in glucose homeostasis, indicating an important and previously unappreciated role for VHL in β-cell function. We believe that the β-cell–specific Vhlh-deficient mice might be a useful tool as a “genetic hypoxia” model, to unravel the possible link between hypoxia signaling and impairment of β-cell function.
Objectively Measured Physical Activity and Its Association With Adiponectin and Other Novel Metabolic Markers
Authors: Metcalf Brad S. , Jeffery Alison N. , Hosking Joanne , Voss Linda D. , Sattar Naveed , Wilkin Terence J.
Published: November 2008

OBJECTIVE—Recent evidence suggests that, in children, traditional markers of metabolic disturbance are related only weakly to physical activity. We therefore sought to establish the corresponding relationships with newer metabolic markers.

RESEARCH DESIGN AND METHODS—This was a nonintervention longitudinal study of 213 healthy children recruited from 54 schools in Plymouth, U.K. MTI accelerometers were used to make objective 7-day recordings of physical activity at ages 5 ± 0.3 (mean ± SD), 6, 7, and 8 years. Overall physical activity was taken as the average of the four annual time points. The metabolic markers at 8 years were adiponectin, leptin, high-sensitivity C-reactive protein (hsCRP), and insulin resistance (homeostasis model assessment). Potential confounders included percent body fat measured by dual-energy X-ray absorptiometry and diet measured by food frequency questionnaire.

RESULTS—Whereas physical activity did not correlate with insulin resistance (r = −0.01), leptin (r = +0.04), or hsCRP (r = +0.01) independently of percent body fat, it did correlate with adiponectin, but inversely (r = −0.18, P = 0.02). This unexpected inverse relationship was strongest among the less active children (physical activity < median: r = −0.30, P = 0.01) but negligible in the more active children (physical activity > median: r = +0.04, P = 0.76). Adiponectin was significantly higher (0.52 SD, P < 0.01) in the least active tertile compared with the other two tertiles. Insulin resistance, however, did not differ across the physical activity tertiles (P = 0.62).

CONCLUSIONS—Adiponectin levels in children are highest among those who are least active, but their insulin resistance is no different. Adiponectin has a known insulin-sensitizing effect, and our findings are consistent with a selective effect at low levels of physical activity.
STM investigation of cobalt silicide nanostructuresâ€™ growth on Si(111)-(âˆš19 Ã— âˆš19) substrate
Authors: Cegiel Maciej , Bazarnik Maciej , Czajka Ryszard
Published: November 2008

Continuing miniaturization of electronic devices necessarily requires assembly of several different objects or devices in a small space. Therefore, besides thin films growth, the possibility of fabricating wires and dots [1, 2] at the nanometre scale composed of metal silicides is of the top interest. This report is about the STM/STS investigation of cobalt silicidesâ€™ nanostructures created on Si(111)-(âˆš19 Ã— âˆš19) substrates via Co evaporation and post deposition annealing. This (âˆš19 Ã— âˆš19) reconstruction was induced by Ni doping. Less than 1ML of Co on surface was obtained. Surface reconstruction induced growth of agglomerates of clusters rather than an uniform layer. The post deposition annealing of a crystal sample (up to 670 K, 770 K, 870 K, 970 K, 1070 K and 1170 K) led to creation of silicidesâ€™ nanostructures. Measurements showed that coalescence of Co nanoislands begun around 970 K. Annealing above 1070 K led to alloying of a Co, Ni and Si. As a consequence the Si(111)-(7Ã—7) reconstruction occurred at the cost of Si(111)-(âˆš19 Ã— âˆš19).
A reliable treatment of the homotopy analysis method for viscous flow over a non-linearly stretching sheet in presence of a chemical reaction and under influence of a magnetic field
Authors: Dinarvand Saeed
Published: November 2008

The similarity solution for the steady two-dimensional flow of an incompressible viscous and electrically conducting fluid over a non-linearly semi-infinite stretching sheet in the presence of a chemical reaction and under the influence of a magnetic field gives a system of non-linear ordinary differential equations. These non-linear differential equations are analytically solved by applying a newly developed method, namely the Homotopy Analysis Method (HAM). The analytic solutions of the system of non-linear differential equations are constructed in the series form. The convergence of the obtained series solutions is carefully analyzed. Graphical results are presented to investigate the influence of the Schmidt number, magnetic parameter and chemical reaction parameter on the velocity and concentration fields. It is noted that the behavior of the HAM solution for concentration profiles is in good agreement with the numerical solution given in reference [A. Raptis, C. Perdikis, Int. J. Nonlinear Mech. 41, 527 (2006)].
Spontaneous encephaloceles of the temporal lobe
Authors: Wind Joshua J. , Caputy Anthony J. , Roberti Fabio
Published: November 2008

Encephaloceles are pathological herniations of brain parenchyma through congenital or acquired osseus-dural defects of the skull base or cranial vault. Although encephaloceles are known as rare conditions, several surgical reports and clinical series focusing on spontaneous encephaloceles of the temporal lobe may be found in the otological, maxillofacial, radiological, and neurosurgical literature. A variety of symptoms such as occult or symptomatic CSF fistulas, recurrent meningitis, middle ear effusions or infections, conductive hearing loss, and medically intractable epilepsy have been described in patients harboring spontaneous encephaloceles of middle cranial fossa origin. Both open procedures and endoscopic techniques have been advocated for the treatment of such conditions. The authors discuss the pathogenesis, diagnostic assessment, and therapeutic management of spontaneous temporal lobe encephaloceles. Although diagnosis and treatment may differ on a case-by-case basis, review of the available literature suggests that spontaneous encephaloceles of middle cranial fossa origin are a more common pathology than previously believed. In particular, spontaneous cases of posteroinferior encephaloceles involving the tegmen tympani and the middle ear have been very well described in the medical literature.
The work horse of skull base surgery: orbitozygomatic approach. Technique, modifications, and applications
Authors: Seçkin Hakan , Avci Emel , Uluç Kutluay , Niemann David , Başkaya Mustafa K.
Published: November 2008

Object

The aim of this study was to describe the microsurgical anatomy of the orbitozygomatic craniotomy and its modifications, and detail the stepwise dissection of the temporalis fascia and muscle and explain the craniotomy techniques involved in these approaches.

Methods

Nine cadaveric embalmed heads injected with colored silicone were used to demonstrate a stepwise dissection of the 3 variations of orbitozygomatic craniotomy. The craniotomies and dissections were performed with standard surgical instruments, and the microsurgical anatomy was studied under microscopic magnification and illumination.

Results

The authors performed 2-piece, 1-piece, and supraorbital orbitozygomatic craniotomies in 3 cadaveric heads each. Stepwise dissection of the temporalis fascia and muscle, and osteotomy cuts were shown and the relevant microsurgical anatomy of the anterior and middle fossae was demonstrated in cadaveric heads. Surgical case examples were also presented to demonstrate the application of and indications for the orbitozygomatic approach.

Conclusions

The orbitozygomatic approach provides access to the anterior and middle cranial fossae as well as the deep sellar and basilar apex regions. Increased bone removal from the skull base obviates the need for vigorous brain retraction and offers an improved multiangled trajectory and shallower operative field. Modifications to the orbitozygomatic approach provide alternatives that can be tailored to particular lesions, enabling the surgeon to use the best technique in each individual case rather than a “one size fits all” approach.
Vascular neurosurgery following the International Subarachnoid Aneurysm Trial: modern practice reflected by subspecialization
Authors: Crocker Matthew , Corns Robert , Hampton Timothy , Deasy Neil , Tolias Christos M.
Published: November 2008

Object

In this paper the authors' goal was to report on and examine (in the context of a large hospital with good endovascular intervention provisions) the activities of a neurosurgeon with a dedicated vascular interest in the era after the International Subarachnoid Aneurysm Trial in the United Kingdom. They also aimed to establish therapeutic trends and outcomes.

Methods

The authors reviewed the multidisciplinary team activity of 1 neurosurgeon and 2 interventional radiologists during a period of 22 months (2005–2007). They reviewed 281 aneurysm interventions; the majority was used to treat subarachnoid hemorrhage. Data analysis showed a strong preference for endovascular treatment for acute rupture (86.6 vs 13.4%), with a progressively greater role for open microsurgery in the more elective context (57% endovascular vs 43% surgical). They also reviewed 66 interventions for arteriovenous malformations, of which only 6 were surgical. These data are compared against a sample year from 2001 to 2002 (pre–International Subarachnoid Aneurysm Trial), showing comparable rates of surgically treated aneurysms versus endovascularly treated aneurysms, but an increase overall in the number of patients requiring open surgery.

Results

The authors found that excellent outcomes for microsurgical clipping compared with endovascular therapy can be achieved within the current climate. These and previously published data strongly support a continuing role for vascular neurosurgery as a subspecialist interest in combination with a dedicated endovascular service and a multidisciplinary team.

Conclusions

Despite a trend to prefer coiling for ruptured aneurysms, the authors have shown that there is still a vital role for open surgery in the management of the ruptured and unruptured aneurysm. They consider the remaining role for surgery for arteriovenous malformations within the modern era of endovascular therapy.
Psychosocial and neurocognitive performance after spontaneous nonaneurysmal subarachnoid hemorrhage related to the APOE-ε4 genotype: a prospective 5-year follow-up study
Authors: Alfieri Alex , Unterhuber Vera , Pircher Martina , Schwarz Andreas , Gazzeri Roberto , Reinert Michael , Widmer Hans R.
Published: November 2008

Object

In this study, the authors prospectively evaluated long-term psychosocial and neurocognitive performance in patients suffering from nonaneurysmal, nontraumatic subarachnoid hemorrhage (SAH) and investigated the association between the APOE-ε4 genotype and outcome in these patients.

Methods

All patients admitted to the authors' institution between January 2001 and January 2003 with spontaneous nonaneurysmal SAH were prospectively examined (mean follow-up 59.8 months). The APOE genotype was determined in all patients by polymerase chain reaction from a blood sample. Of the 30 patients included in this study, 11 were carriers of the ε4 allele.

Results

All patients showed a good recovery and regained full independence with no persisting neurological deficits. The patients with the ε4 allele, however, scored significantly higher on the Beck Depression Inventory (22.1 ± 6.3 vs 14.1 ± 5.1). At follow-up, depression was more persistent in the group with the ε4 allele compared with the group that lacked the allele. This finding reached statistical significance (p < 0.05). Selective attention was impaired in all patients during the first year of follow-up, with an earlier recovery noted in the patients without the ε4 allele. Moreover, there was a tendency toward a linear relationship between the Beck Depression Inventory and the d2 Test of Attention. Two patients who carried the ε4 allele did not return to their employment even after 5 years.

Conclusions

The findings in this study suggest that the APOE genotypes may be associated with the psychosocial and neurocognitive performance after spontaneous nonaneurysmal SAH, even in the absence of neurological impairment. Physicians should consider patient genotype in assessing the long-term consequences of nonaneurysmal SAH.