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The role of cross-linking structures to the formation of one-dimensional nano-organized polyaniline and their Raman fingerprint

NASCIMENTO, Gustavo M. do; SILVA, Claudio H. B.; IZUMI, Celly M. S.; TEMPERINI, Marcia L. A.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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In the present work. the resonance Raman. UV-vis-NIR and scanning electron microscopic (SEM) data of nanorods (about similar to 300 rim in diameter) and nanofibers (about similar to 93 nm in diameter) of PANI are presented and compared. The PANI samples were synthesized in aqueous media with dodecybenzenesulfonic acid (DBSA) and beta-naphtalenesulfonic acid (beta-NSA) as dopants, respectively. The presence of hands at 578, 1400 and 1632cm(-1) in the Raman spectra of PANI-NSA and PANI-DBSA shows that the formation of cross-linking structures is a general feature of the PANI chains prepared in micellar media. It is proposed that these structures are responsible for the one-dimensional PANI morphology formation. In addition, the Raman band at 609cm(-1) of PANI fibers is correlated with the extended PANI chain coil formation. (C) 2008 Elsevier B.V. All rights reserved.; FAPESP (Brazilian agency); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Peripheral Sterile Corneal Ring Infiltrate After Riboflavin-UVA Collagen Cross-Linking in Keratoconus

Ghanem, Ramon C.; Netto, Marcelo V.; Ghanem, Vinicius C.; Santhiago, Marcony R.; Wilson, Steven E.
Fonte: LIPPINCOTT WILLIAMS & WILKINS; PHILADELPHIA Publicador: LIPPINCOTT WILLIAMS & WILKINS; PHILADELPHIA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Purpose: To present 7 cases of peripheral sterile corneal infiltrates that occurred after corneal cross-linking (CXL) for progressive keratectasia. Methods: Seven patients who had their progressive keratoconus documented underwent corneal deepithelization and subsequently CXL, which was performed with the application of 0.1% riboflavin with 20% dextran, and exposure to UVA light (370 nm, 2.9-3.1 mW/cm(2)) for 30 minutes. Results: Nearly a week after the procedure, the patients presented with peripheral stromal infiltrates. The ring-like infiltrates were superficial and were present at the 9.0-mm zone. Sterile infiltration was diagnosed. Patients were treated with topical corticosteroids, and complete resolution was achieved after a few weeks of treatment. Conclusions: We hypothesize that the phototoxic effect on the corneal stroma may be the main mechanism that triggers these infiltrates. Alternatively, alterations in antigenicity that occur in native proteins after CXL could result in patients recognizing the proteins as nonself and mounting immune responses.

Corneal Absorption of a New Riboflavin-Nanostructured System for Transepithelial Collagen Cross-Linking

Bottos, Katia M.; Oliveira, Anselmo Gomes de; Bersanetti, Patrícia A.; Nogueira, Regina F.; Lima-Filho, Acácio A. S.; Cardillo, José A.; Schor, Paulo; Chamon, Wallace
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Corneal collagen cross-linking (CXL) has been described as a promising therapy for keratoconus. According to standard CXL protocol, epithelium should be debrided before treatment to allow penetration of riboflavin into the corneal stroma. However, removal of the epithelium can increase procedure risks. In this study we aim to evaluate stromal penetration of a biocompatible riboflavin-based nanoemulsion system (riboflavin-5-phosphate and riboflavin-base) in rabbit corneas with intact epithelium. Two riboflavin nanoemulsions were developed. Transmittance and absorption coefficient were measured on corneas with intact epithelia after 30, 60, 120, 180, and 240 minutes following exposure to either the nanoemulsions or standard 0.1% or 1% riboflavin-dextran solutions. For the nanoemulsions, the epithelium was removed after measurements to assure that the riboflavin had passed through the hydrophobic epithelium and retained within the stroma. Results were compared to de-epithelialized corneas exposed to 0.1% riboflavin solution and to the same riboflavin nanoemulsions for 30 minutes (standard protocol). Mean transmittance and absorption measured in epithelialized corneas receiving the standard 0.1% riboflavin solution did not reach the levels found on the debrided corneas using the standard technique. Neither increasing the time of exposure nor the concentration of the riboflavin solution from 0.1% to 1% improved riboflavin penetration through the epithelium. When using riboflavin-5-phosphate nanoemulsion for 240 minutes...

Utilização de espectrometria de massas, ligação cruzada (cross-linking) e footprinting no estudo de interações proteina-proteina; Use of mass spectrometry, cross-linking and footprinting in the study of protein-protein interactions

Amadeu Hoshi Iglesias
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/04/2009 PT
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A Espectrometria de Massas (MS) é hoje a principal técnica de caracterização de estrutura primária de proteínas devido às vantagens intrínsecas da técnica. As técnicas de cross-linking e footprinting visam desfrutar de tais vantagens para obtenção de informações estruturais de complexos protéicos. Nesse projeto foram realizados estudos de fragmentação de peptídeos contendo como cross-linker o DSS, reagente mais utilizado para esse propósito. Os mecanismos de fragmentação foram propostos baseados na dissociação de peptídeos modelos sintetizados para gerar espécies que mimetizassem experimentos com proteínas. Esses estudos permitiram a identificação de íons marcadores, que foram posteriormente utilizados em experimentos de Varredura de Íons Precursores para auxiliar na detecção de peptídeos modificados. Para realização dos experimentos de footprinting, foi desenvolvida uma linha de luz no LNLS. Posteriormente, foi proposto um novo método de quantificação de cinética de oxidação baseado nos dados de LC-MS, levando em consideração todos os produtos de oxidação formados. Esses métodos foram utilizados no estudo de interação das proteínas Tif34 e Tif35 do fator de iniciação de tradução de Saccharomyces cerevisiae. Os resultados obtidos indicam que Tif34 apresenta dois possíveis sítios de interação para a proteína Tif35; Mass Spectrometry (MS) is the most important tool for analyses related to protein primary structure. Cross-Linking and footprinting aim to bring those advantages to gain insights in the spatial structure of protein complexes. In this work the fragmentation of peptides containing DSS...

Estudo teorico e experimental de proteomica estrutural por espectrometria de massas acoplada a ligação cruzada; Experimental and theoretical study of structural proteomics by mass spectrometry coupled to cross-linking

Alana dos Reis Figueiredo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/02/2010 PT
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A espectrometria de massas (MS) desempenha um papel fundamental na proteômica, pois permite a identificação de proteínas, seqüenciamento de peptídeos, determinação de modificações pós-traducionais e análise quantitativa de expressão. Além das análises envolvendo a estrutura primária, há um grande interesse em se aplicar MS para análise de estruturas superiores (terciárias e quaternárias) de proteínas e uma das abordagens promissoras nesta área é a MS acoplada à ligação cruzada. Nesta abordagem, um reagente bifuncional liga covalentemente resíduos de aminoácidos espacialmente próximos e a distância máxima entre esses resíduos é dado pelo tamanho do agente de ligação cruzada (ALC). Nesse trabalho avaliou-se a extensão e exatidão das distâncias interresíduos tanto por simulações de dinâmica molecular quanto por experimentos de MS. As faixas de distâncias calculadas mostram que há sempre uma distância mínima entre resíduos ao qual o ALC pode se ligar, além de determinar o valor máximo para cada um dos ALC estudados (DSG, DSS e DSSeb). Os dados experimentais com proteínas modelo (Ubiquitina, Citocromo C e Mioglobina) mostraram ainda que todos dos peptídeos que apresentavam ligações cruzadas estavam dentro da faixa de alcance determinadas pelas simulações de dinâmica molecular...

Uso de espectrometria de massas e mobilidade iônica na caracterização de peptídeos provenientes de experimentos de ligação cruzada; Mass spectrometry and ion mobility in the characterization and of peptides from protein cross-linking experiments

Luiz Fernando Arruda Santos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 10/03/2011 PT
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A função de uma proteína está diretamente relacionada com sua estrutura e conhecendo a estrutura de uma proteína é possível verificar onde estão localizados e como agem seus sítios ativos e de interação. Dentre os métodos empregados para análise estrutural de proteínas por espectrometria de massas (MS), experimentos de ligação cruzada vêm recebendo grande destaque. Nestes experimentos, após digestão enzimática três tipos de peptídeos contendo agentes de ligação cruzada (ALCs) podem ser formados: espécies intramoleculares, quando o ALC está ligado entre dois resíduos do mesmo peptídeo; espécies intermoleculares, quando o ALC une dois peptídeos distintos e dead-end, quando o ALC liga-se apenas a um resíduo, sendo que o outro lado de sua cadeia normalmente sofre hidrólise. A etapa crucial em experimento de ligação cruzada consiste na correta atribuição e identificação dos peptídeos modificados por ALC, etapa que pode ser facilitada conhecendo a fragmentação destes peptídeos. Desse modo, o foco principal deste trabalho foi realizar experimentos de fragmentação das diferentes espécies de peptídeos modificados por ALCs utilizando metodologias baseadas na técnica de espectrometria de massas, como dissociação induzida por colisão (CID)...

Effects of imidacloprid exposure on Chironomus riparius Meigen larvae: Linking acetylcholinesterase activity to behaviour

Azevedo-Pereira, HMVS; Lemos, MFL; Soares, AMVM
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.32%
Imidacloprid (IMI) is an insecticide that interferes with the transmission of stimuli in the nervous system of insects. It is neurotoxic by mimicking nicotine through its binding to the nicotinic acetylcholine receptor. In this work, experiments comprising 96 h exposure followed by 48 h in clean medium were conducted to evaluate the toxicity of IMI to Chironomus riparius and its potential recovery. Behavioural parameters and AChE activity were assessed. After 96 h exposure to IMI, AChE activity, and the behaviour parameters ventilation and locomotion were reduced. There were no signs of recovery after removal to clean water for 48 h. Ventilation behaviour was the most sensitive parameter and the one with the highest correlation to AChE activity. Despite the possibility that IMI might be having an indirect effect on AChE activity, the behavioural endpoint showed a higher sensitivity than the biochemical response itself. This work highlights the importance of linking parameters with ecological relevance at individual level (behavioural parameters) with biochemical responses, to unravel xenobiotics mode of action. (C) 2011 Elsevier Inc. All rights reserved.

Corneal thickness changes during corneal collagen cross-linking with UV-A irradiation and hypo-osmolar riboflavin in thin corneas

Nassaralla,Belquiz Amaral; Vieira,Diogo Mafia; Machado,Márcia Leite; Figueiredo,Marisa Novaes Faleiro Chaves de; Nassaralla Jr,João Jorge
Fonte: Conselho Brasileiro de Oftalmologia Publicador: Conselho Brasileiro de Oftalmologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
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PURPOSE: To evaluate the thinnest corneal thickness changes during and after corneal collagen cross-linking treatment with ultraviolet-A irradiation, using hypo-osmolar riboflavin solution in thin corneas. METHODS: Eighteen eyes of 18 patients were included in this study. After epithelium removal, iso-osmolar 0.1% riboflavin solution was instilled to the cornea every 3 minutes for 30 minutes. Hypo-osmolar 0.1% riboflavin solution was then applied every 20 seconds for 5 minutes or until the thinnest corneal thickness reached 400 µm. Ultraviolet-A irradiation was performed for 30 minutes. During irradiation, iso-osmolar 0.1% riboflavin drops were applied every 5 minutes. Ultrasound pachymetry was performed at approximately the thinnest point of the cornea preoperatively, after epithelial removal, after iso-osmolar riboflavin instillation, after hypo-osmolar riboflavin instillation, after ultraviolet-A irradiation, and at 1, 6 and 12 months after treatment. RESULTS: Mean preoperative thinnest corneal thickness was 380 ± 11 µm. After epithelial removal it decreased to 341 ± 11 µm, and after 30 minutes of iso-osmolar 0.1% riboflavin drops, to 330 ± 7.6 µm. After hypo-osmolar 0.1% riboflavin drops, mean thinnest corneal thickness increased to 418 ± 11 µm. After UVA irradiation...

Changes in corneal sensitivity following cross-linking for progressive early-stage keratoconus

Lago,Anelise de Medeiros; Nassaralla,Belquiz R. do Amaral; Stival,Larissa Rossana Souza; Nassaralla Junior,João Jorge
Fonte: Conselho Brasileiro de Oftalmologia Publicador: Conselho Brasileiro de Oftalmologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
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Purpose: To evaluate changes in corneal sensitivity following corneal cross-linking (CXL) in patients with progressive earlier stage keratoconus. Methods: Thirty-eight eyes of 19 patients (11 women, 8 men) were included in a prospective, nonrandomized clinical study. The mean patient age was 22 years (range, 18-26 years). Inclusion criteria were early stage bilateral progressive keratoconus, a transparent cornea, and a thickness of ≥440 µm in the thinnest area of the cornea. Using the Cochet-Bonnet esthesiometer, central corneal sensitivity was measured before surgery, 7 days after surgery, and once a month thereafter until recovery of baseline preoperative levels. Central corneal sensitivity >40 mm was considered normal. Results: Corneal sensitivity gradually returned to preoperative levels in all treated eyes. The mean central corneal sensitivity was 52.2, 24.0, 38.2, 42.5, 50.0, and 52.5 mm before surgery, 7 days after surgery, and at 1, 2, 3, and 4 months after surgery, respectively. Normal levels of corneal sensation, but not baseline (preoperative) levels, were observed 2 months after surgery. The preoperative levels were observed 3 months after surgery. Conclusions: Our results suggest that central corneal sensitivity can be decreased for as long as 3 months after CXL for progressive earlier stage keratoconus.

Induction of corneal collagen cross-linking in experimental corneal alkali burns in rabbits

Colombo-Barboza,Marcello; Colombo-Barboza,Guilherme; Felberg,Sergio; Dantas,Paulo Elias Corrêa; Sato,Elcio Hideo
Fonte: Conselho Brasileiro de Oftalmologia Publicador: Conselho Brasileiro de Oftalmologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2014 EN
Relevância na Pesquisa
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Objective: To evaluate the effect of riboflavin-ultraviolet-A-induced cross-linking (CXL) following corneal alkali burns in rabbits. Methods: The right corneas and limbi of ten rabbits were burned using a 1N solution of NaOH and the animals were then divided into two groups: a control group submitted to clinical treatment alone and an experimental group that was treated 1 h after injury with CXL, followed by the same clinical treatment as administered to the controls. Clinical parameters were evaluated post-injury at 1, 7, 15, and 30 days by two independent observers. Following this evaluation, the corneas were excised and examined histologically. Results: There were no statistically significant differences in clinical parameters, such as hyperemia, corneal edema, ciliary injection, limbal ischemia, secretion, corneal neovascularization, symblepharon, or blepharospasm, at any of the time-points evaluated. However, the size of the epithelial defect was significantly smaller in the CXL group (p<0.05) (day 15: p=0.008 and day 30: p=0.008) and the extent of the corneal injury (opacity lesion) was also smaller (day 30: p=0.021). Histopathology showed the presence of collagen bridges linking the collagen fibers in only the CXL group. Conclusions: These results suggest that the use of CXL may improve the prognosis of acute corneal alkali burns.

Polysemy, polyvalence, and linking mismatches: the concept of RAIN and its codings in English, German, Italian, and Spanish

Zaefferer,Dietmar
Fonte: Pontifícia Universidade Católica de São Paulo - PUC-SP Publicador: Pontifícia Universidade Católica de São Paulo - PUC-SP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2002 EN
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Based on an ontological frame for comparative onomasiological lexicology which embeds the RAIN eventity type as an exponent-shaped activity into a general linguistic ontology as well as an ontology of motion, the words for RAIN in two Germanic and two Romance languages are compared with respect to their semantic and syntactic variability. It turns out that the Germanic forms are more flexible than the Romance forms. English rain has the highest variability: It can be used with eight valencies, a nominal and seven verbal ones, and with five different meanings, and it is the only one to display a valence that combines an expletive subject with a cognate object as well as a causativized eventity meaning. On the other hand only German regnen has a resultativized meaning. The Romance languages too show some internal variance: In allowing both an impersonal construction with a generalized meaning and a source construction, Spanish llover is slightly more flexible than Italian piovere. Finally, an Optimality Theoretic account of the data is adumbrated in terms of three principles: Avoid linking mismatches, Avoid heterogeneity of sentence patterns, and Avoid redundancy.

Linking hypotheses underlying Class A and Class B methods

MORGAN, M.J.; MELMOTH, D.; SOLOMON, J.A.
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
Publicado em /11/2013 EN
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36.42%
Class A psychophysical observations are based on the linking hypothesis that perceptually distinguishable stimuli must correspond to different brain events. Class B observations are related to the appearance of stimuli not their discriminability. There is no clear linking hypothesis underlying Class B observations, but they are necessary for studying the effects of context on appearance, including a large class of phenomena known as “illusions.” Class B observations are necessarily measures of observer bias (Fechner’s “constant error”) as opposed to Class A measures of sensitivity (Fechner’s “variable error”). It is therefore important that Class B observations distinguish between response biases, decisional biases, and perceptual biases. This review argues that the commonly used method of single stimuli fails to do this, and that multiple-alternative forced choice (mAFC) methods can do a better job, particularly if combined with a roving pedestal.

Efeito terapêutico do cross-linking corneal em portadores de ceratopatia bolhosa sintomática

Nery Benevides Gadelha, Diego; Teixeira Brandt, Carlos (Orientador)
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Outros
PT_BR
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36.42%
Objetivo: Avaliar o efeito do cross-linking corneal (CCL) nos portadores de ceratopatia bolhosa sintomática, e seu impacto na acuidade visual, espessura corneal e sintomatologia dolorosa. Métodos: Doze pacientes com ceratopatia bolhosa sintomática foram incluídos. Exame clínico com questionário específico para a pesquisa com escala de dor (escala visual analógica numérica), acuidade visual e mensuração da espessura corneal foi realizada pré CCL, 7, 30, 60, 180 e 365 dias após. Em todos os pacientes o tratamento com UVA-crosslinking foi realizado após abrasão do epitélio corneal em lâmpada de fenda e instilação de solução de riboflavina 0,1% a cada cinco minutos por 30 minutos. Após esse período, o paciente foi submetido à exposição à luz UVA, utilizando riboflavina e anestesia tópica a cada cinco minutos por 30 minutos. Os pacientes utilizaram colírios de ofloxacina 0,3% e lágrima artificial até completa reepitelização. O teste de Friedman foi usado para comparar as médias das freqüências da acuidade visual, sintomatologia dolorosa e espessura central da córnea. p <0.05 foi utilizado para rejeitar a hipótese nula. Resultados: Doze olhos de 12 pacientes com erosões epiteliais recorrentes foram tratados. O tempo de seguimento foi de um ano. Foi observada redução significante da dor (p<0...

Linking historical census data across time

Fu, Zhichun
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
EN_AU
Relevância na Pesquisa
36.66%
Historical census data provide a snapshot of the era when our ancestors lived. Such data contain valuable information for the reconstruction of households and the tracking of family changes across time, which can be used for a variety of social science research projects. As valuable as they are, these data provide only snapshots of the main characteristics of the stock of a population. To capture household changes requires that we link person by person and household by household from one census to the next over a series of censuses. Once linked together, the census data are greatly enhanced in value. Development of an automatic or semi-automatic linking procedure will significantly relieve social scientists from the tedious task of manually linking individuals, families, and households, and can lead to an improvement of their productivity. In this thesis, a systematic solution is proposed for linking historical census data that integrates data cleaning and standardisation, as well as record and household linkage over consecutive censuses. This solution consists of several data pre-processing, machine learning, and data mining methods that address different aspects of the historical census data linkage problem. A common property of these methods is thatthey all adopt a strategy to consider a household as an entity...

Analysis of Shigella flexneri Wzz (Rol) function by mutagenesis and cross-linking: Wzz is able to oligomerise.

Daniels, C.; Morona, R.
Fonte: BLACKWELL SCIENCE LTD Publicador: BLACKWELL SCIENCE LTD
Tipo: Artigo de Revista Científica
Publicado em //1999 EN
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The modal length or degree of polymerization (dp) of the Shigella flexneri O-antigen is determined in an unknown manner by the Wzz/Rol protein. The Wzz protein is anchored into the cytoplasmic membrane by two transmembrane domains (TM1 amino acids 32-52; TM2 amino acids 295-315) with the central loop of the protein located in the periplasm. Plasmids were constructed encoding hybrid Wzz proteins consisting of regions of S. flexneri Wzz (WzzSF) and Salmonella typhimurium Wzz (WzzST). These imparted O-antigen modal chain lengths that implied that the carboxy-terminal region of Wzz was involved in chain length determination. Site-directed mutagenesis was undertaken to investigate the functional significance of highly conserved residues in amino-/carboxy-terminal domains of WzzSF. Some of the WzzSF variants resulted in O-antigen modal chain lengths much shorter than those of wild-type WzzSF, whereas other mutants inactivated WzzSF function entirely and a third class had a longer O-antigen chain length distribution. The data indicate that amino acids throughout the length of the WzzSF protein are important in determination of O-antigen modal chain length. In vivo cross-linking experiments were performed to investigate the interactions between Wzz proteins. The experiments indicated that the WzzSF protein is able to form dimers and oligomers of at least six WzzSF proteins. A carboxy-terminal-truncated WzzSF protein having the amino terminal 194 amino acids was able to oligomerize...

A novel tetrafunctional reagent for simultaneous intramolecular and intermolecular cross-linking of bovine hemoglobin

Yun, Q.; He, M.; Xing, W.; Bi, J.; Ma, G.; Su, Z.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
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A novel tetrafunctional reagent, α, γ, α, γ-tetra-succinimidyl-hexanediamide-di-glutamate ester (HDG(OSu)4), was successfully synthesized, and a well-defined cross-linked bovine hemoglobin (mainly 128 kDa) was prepared with this reagent. Due to the spatial structure of this cross-linking reagent, the intramolecular and intermolecular cross-linking of bovine hemoglobin was formed simultaneously in one reaction. Although the cross-linked bovine hemoglobin showed a slight decrease in half-saturated O2 pressure value (P50, from 28.1 mm Hg to 21.7 mm Hg) and Hill coefficient (from 2.5 to 2), due to the cross-linkage, it still performed well for O2 delivery.; Qiang Yun, Minglei He, Wenchao Xing, Jingxiu Bi, Guanghui Ma & Zhiguo Su; The definitive version may be found at http://www.springerlink.com/

Photo-Induced Cross-Linking of Unmodified Proteins (PICUP) Applied to Amyloidogenic Peptides

Rahimi, Farid; Maiti, Panchanan; Bitan, Gal
Fonte: MyJove Corporation Publicador: MyJove Corporation
Tipo: Artigo de Revista Científica
Publicado em 12/01/2009 EN
Relevância na Pesquisa
36.61%
The assembly of amyloidogenic proteins into toxic oligomers is a seminal event in the pathogenesis of protein misfolding diseases, including Alzheimer's, Parkinson's, and Huntington's diseases, hereditary amyotrophic lateral sclerosis, and type 2 diabetes. Owing to the metastable nature of these protein assemblies, it is difficult to assess their oligomer size distribution quantitatively using classical methods, such as electrophoresis, chromatography, fluorescence, or dynamic light scattering. Oligomers of amyloidogenic proteins exist as metastable mixtures, in which the oligomers dissociate into monomers and associate into larger assemblies simultaneously. PICUP stabilizes oligomer populations by covalent cross-linking and when combined with fractionation methods, such as sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or size-exclusion chromatography (SEC), PICUP provides snapshots of the oligomer size distributions that existed before cross-linking. Hence, PICUP enables visualization and quantitative analysis of metastable protein populations and can be used to monitor assembly and decipher relationships between sequence modifications and oligomerization1. Mechanistically, PICUP involves photo-oxidation of Ru2+ in a tris(bipyridyl)Ru(II) complex (RuBpy) to Ru3+ by irradiation with visible light in the presence of an electron acceptor. Ru3+ is a strong one-electron oxidizer capable of abstracting an electron from a neighboring protein molecule...

Modelling the structure of latexin-carboxypeptidase A complex based on chemical cross-linking and molecular docking

Mouradov, Dmitri; Craven, Ari; Forwood, Jade; Flanagan, Jack U; Garcia-Castellanos, Raquel; Gomis-Ruth, F. Xavier; Hume, D A; Martin, Jennifer Louise; Kobe, Bostjan; Huber, Thomas
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.42%
We have determined the three-dimensional structure of the protein complex between latexin and carboxypeptidase A using a combination of chemical cross-linking, mass spectrometry and molecular docking. The locations of three intermolecular cross-links were

Linking Meaning to Language: Linguistic Universals and Variation

Snedeker, Jesse; Hartshorne, Joshua Keiles; O'Donnell, Timothy J.; Sudo, Yasutada; Uruwashi, Miki
Fonte: Cognitive Science Society Publicador: Cognitive Science Society
Tipo: Conference Paper
EN_US
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To use natural language, speakers must map the participants in events or states in the world onto grammatical roles. There remains considerable disagreement about the nature of these so-called linking rules (Levin & Rappaport Hovav, 2005). In order to probe the nature of linking rules, we investigate verbs of psychological state, which demonstrate complex linking patterns both within and between languages. We find that the typical duration of the psychological state guides the application of linking rules to novel verbs in both English and Japanese, consistent with a universal constraint. Nonetheless, there are marked differences in the baseline preferences for the individual linking rules across the two languages. We discuss these findings both in terms of theories of exceptionless linking rules and accounts on which linking rules are governed by probabilistic biases as well as cross-linguistic variation.; Psychology

Speaker diarisation and longitudinal linking in multi-genre broadcast data

Karanasou, P.; Gales, M. J. F.; Lanchantin, P.; Liu, X.; Qian, Y.; Wang, L.; Woodland, P. C.; Zhang, C.
Fonte: IEEE Publicador: IEEE
Tipo: Article; accepted version
EN
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This is the accepted manuscript. It is currently embargoed pending publication.; This paper presents a multi-stage speaker diarisation system with longitudinal linking developed on BBC multi-genre data for the 2015 Multi-Genre Broadcast (MGB) challenge. The basic speaker diarisation system draws on techniques from the Cambridge March 2005 system with a new deep neural network (DNN)-based speech/non speech segmenter. A newly developed linking stage is next added to the basic diarisation output aiming at the identification of speakers across multiple episodes of the same series. The longitudinal constraint imposes an incremental processing of the episodes, where speaker labels for each episode can be obtained using only material from the episode in question, and those broadcast earlier in time. The nature of the data as well as the longitudinal linking constraint position this diarisation task as a new open-research topic, and a particularly challenging one. Different linking clustering metrics are compared and the lowest within-episode and cross-episode DER scores are achieved on the MGB challenge evaluation set.; This work is in part supported by EPSRC Programme Grant EP/I031022/1 (Natural Speech Technology). C. Zhang is also supported by a Cambridge International Scholarship from the Cambridge Commonwealth...