6,670 research outputs found
Evidence for entanglement at high temperatures in an engineered molecular magnet
The molecular compound
[Fe(-oxo)(CHN)(CO)]
was designed and synthesized for the first time and its structure was
determined using single-crystal X-ray diffraction. The magnetic susceptibility
of this compound was measured from 2 to 300 K. The analysis of the
susceptibility data using protocols developed for other spin singlet
ground-state systems indicates that the quantum entanglement would remain at
temperatures up to 732 K, significantly above the highest entanglement
temperature reported to date. The large gap between the ground state and the
first-excited state (282 K) suggests that the spin system may be somewhat
immune to decohering mechanisms. Our measurements strongly suggest that
molecular magnets are promising candidate platforms for quantum information
processing
Morphology, mechanical characterization and in vivo neo-vascularization of chitosan particle aggregated scaffolds architectures
The present study intended to evaluate the performance of chitosan-based scaffolds produced by
a particle aggregation method aimed to be used in tissue engineering applications addressing key issues
such as morphological characteristics, mechanical performance and in vivo behaviour. It is claimed that
the particle aggregation methodology may present several advantages, such as combine simultaneously
a high interconnectivity with high mechanical properties that are both critical for an in vivo successful
application. In order to evaluate these properties, micro-Computed Tomography (micro-CT) and Dynamical
Mechanical Analysis (DMA) were applied. The herein proposed scaffolds present an interesting
morphology as assessed by micro-CT that generally seems to be adequate for the proposed applications.
At a mechanical level, DMA has shown that chitosan scaffolds have an elastic behaviour under dynamic
compression solicitation, being simultaneously mechanically stable in the wet state and exhibiting
a storage modulus of 4.21 ! 1.04 MPa at 1 Hz frequency. Furthermore, chitosan scaffolds were evaluated
in vivo using a rat muscle-pockets model for different implantation periods (1, 2 and 12 weeks). The
histological and immunohistochemistry results have demonstrated that chitosan scaffolds can provide
the required in vivo functionality. In addition, the scaffolds interconnectivity has been shown to be
favourable to the connective tissues ingrowth into the scaffolds and to promote the neo-vascularization
even in early stages of implantation. It is concluded that the proposed chitosan scaffolds produced by
particle aggregation method are suitable alternatives, being simultaneously mechanical stable and in vivo
biofunctional that might be used in load-bearing tissue engineering applications, including bone and
cartilage regeneration.The authors would like to acknowledge the Portuguese Foundation for Science and Technology for the PhD Grant to Patricia B Malafaya (SFRH/BD/11155/2002). This work was partially supported and carried out under the scope of the European STREP Project HIPPOCRATES (NMP3-CT-2003-505758) and European NoE EXPERTISSUES (NMP3-CT-2004-500283). The authors also thank Prof. Heinz Redl for the collaboration in the in VIVO Studies, as well as Bernhard Horing for the surgical procedures both from LBI, Austria and Joao Oliveira from 3B's Research Group, Portugal for the initial assistance with the DMA equipment
Sistemas de rotação de culturas com trigo para a região sul do Brasil.
bitstream/item/84156/1/CNPT-COM.-TEC.-2-97.pd
ANÁLISE DA QUALIDADE DO SERVIÇO: UMA APLICAÇAO DO MODELO SERPERF EM DUAS AGÊNCIAS BANCÁRIAS DE CAMPOS DOS GOYTACAZES
Em um ambiente de grande competitividade e constantes instabilidades, as empresas buscam formas
inovadoras para atrair e manter seus clientes. A diferenciação destas empresas reside em um atendimento
qualificado, tornando esse fator determinante na sobrevivência no mercado, utilizando dessa postura de
aproximação com os clientes como estratégia para manter-se lucrativos. Nesse contexto, as empresas
precisam suprir os interesses e necessidades de seus stakeholders, pois satisfação reflete seus compromissos
com ética e princípios moralmente aceitos pelas comunidades (SANTOS, 2011). O Objetivo deste trabalho
de consiste em avaliar o desempenho do serviço prestado por agências bancaria da região Norte Fluminense,
utilizando a ferramenta SERVPERF, segundo a percepção dos usuários e gestores. O SERVPERF é o modelo
desenvolvido por Cronin e Taylor (1992) para avaliar o desempenho dos serviços prestados, levando em
consideração a visão dos clientes. Segundo Junior e Bornia (2011) o SERVPERF utiliza apenas a qualidade
percebida na avaliação da satisfação. Já Salomi, Miguel e Abackerli (2005) concluem que o instrumento
SERVPERF é mais sensível em retratar as variações de qualidade em relação às outras escalas. A abordagem
metodológica deste artigo consiste na coleta de dados primários, de forma quantitativa por meio de
questionários de questões fechadas, entregue aos clientes de duas agências de Campos dos Goytacazes. A
amostra da pesquisa será composta por 100 clientes de duas agências bancárias do município de Campos dos
Goytacazes. Segundo Vicente, Junior e Hora (2014) os dados constantes nos questionários respondidos
pelos clientes das agências bancárias serão utilizados não apenas para comprovar a hipótese do bom
atendimento ou não da empresa analisada, mas também será usada para a elaboração de gráficos sobre o
nível de desempenho do atendimento prestado por essa empresa do setor bancário em Campos dos
Goytacazes. A elaboração do questionário foi realizada por meio da adaptação do modelo utilizado pelos
autores Junior e Bornia (2011). O questionário é composto por 35 questões das quais espera-se que, após a
conclusão da pesquisa seja possível identificar critérios importantes e inerentes a qualidade do desempenho
dos serviços prestados nas agências bancárias. Para a composição do questionário, foram selecionadas as
seguintes dimensões da qualidade em serviços que compõe o modelo SERVPERF: I) Confiabilidade - Prestar
serviço como prometido, com precisão consistência e segurança; II) Rapidez - Velocidade de atendimento e
prontidão para atender o cliente; III) Tangíveis – Refere-se a quaisquer evidenciais físicas do serviço, como
instalações físicas, aparência dos funcionários e equipamentos utilizados no processo; Empatia -
Cordialidade, cuidados e atenções individual fornecidas ao cliente; IV) Flexibilidade - Capacidade de mudar
e adaptar o serviço para se ajustar as necessidades dos clientes; V) Acesso - Facilidade de entrar em contato
ou acessar fisicamente os serviço; Disponibilidade - Facilidade de encontrar disponível pessoal de
atendimento, bens, facilitadores e instalações. Espera-se que por meio da elaboração do questionário e
seleção das dimensões estudadas, possa seja apurado o grau do desempenho dos serviços prestados pelas
agências estudadas
Natural origin scaffolds with in situ pore forming capability for bone tissue engineering applications
This work describes the development of a biodegradable matrix, based on chitosan and starch, with the ability to form a porous structure
in situ due to the attack by specific enzymes present in the human body (a-amylase and lysozyme). Scaffolds with three different
compositions were developed: chitosan (C100) and chitosan/starch (CS80-20, CS60-40). Compressive test results showed that these materials
exhibit very promising mechanical properties, namely a high modulus in both the dry and wet states. The compressive modulus in
the dry state for C100 was 580 ± 33 MPa, CS80-20 (402 ± 62 MPa) and CS60-40 (337 ± 78 MPa). Degradation studies were performed
using a-amylase and/or lysozyme at concentrations similar to those found in human serum, at 37 C for up to 90 days. Scanning electron
micrographs showed that enzymatic degradation caused a porous structure to be formed, indicating the potential of this methodology to
obtain in situ forming scaffolds. In order to evaluate the biocompatibility of the scaffolds, extracts and direct contact tests were performed.
Results with the MTT test showed that the extracts of the materials were clearly non-toxic to L929 fibroblast cells. Analysis
of cell adhesion and morphology of seeded osteoblastic-like cells in direct contact tests showed that at day 7 the number of cells on
CS80-20 and CS60-40 was noticeably higher than that on C100, which suggests that starch containing materials may promote cell adhesion
and proliferation. This combination of properties seems to be a very promising approach to obtain scaffolds with gradual in vivo
pore forming capability for bone tissue engineering applications.This work was supported by the European NoE EXPERTISSUES (NMP3-CT-2004-500283), the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and the Portuguese Foundation for Science and Technology (FCT) through POCTI and/or FEDER programmes
Morphometric and mechanical characterization, insulin loading and in-vivo biocompatibility of chitosan particles aggregated scaffolds for tissue engineering
In tissue engineering, scaffolds development presents, among others, 3 key requirements: adequate morphological characteristics, mechanical performance and in-vivo biocompatibility. The aim of
the present study was to evaluate chitosan-based scaffolds produced by particle aggregation in these key issues. Furthermore, chitosan scaffolds were loaded with insulin to promote chondrogenic differentiation.
Micro-Computed Tomography (m-CT) was carried out for accurate morphometric characterization quantifying porosity, interconnectivity, particles and pores size that shown to be adequate. Dynamical Mechanical Analysis (DMA) showed that scaffolds are mechanically stable in wet state with a storage modulus of 4.21 1.04 MPa at 1Hz frequency. Insulin-loaded scaffolds were characterized and studied with a pre-chondrogenic cell line
(ATDC-5). The in-vitro release was carried out mimicking cell culture conditions quantified by micro-BCA. [...]info:eu-repo/semantics/publishedVersio
Breaking Barriers: Bioinspired Strategies for Targeted Neuronal Delivery to the Central Nervous System
Central nervous system (CNS) disorders encompass a vast spectrum of pathological conditions and represent a growing concern worldwide. Despite the high social and clinical interest in trying to solve these pathologies, there are many challenges to bridge in order to achieve an effective therapy. One of the main obstacles to advancements in this field that has hampered many of the therapeutic strategies proposed to date is the presence of the CNS barriers that restrict the access to the brain. However, adequate brain biodistribution and neuronal cells specific accumulation in the targeted site also represent major hurdles to the attainment of a successful CNS treatment. Over the last few years, nanotechnology has taken a step forward towards the development of therapeutics in neurologic diseases and different approaches have been developed to surpass these obstacles. The versatility of the designed nanocarriers in terms of physical and chemical properties, and the possibility to functionalize them with specific moieties, have resulted in improved neurotargeted delivery profiles. With the concomitant progress in biology research, many of these strategies have been inspired by nature and have taken advantage of physiological processes to achieve brain delivery. Here, the different nanosystems and targeting moieties used to achieve a neuronal delivery reported in the open literature are comprehensively reviewed and critically discussed, with emphasis on the most recent bioinspired advances in the field. Finally, we express our view on the paramount challenges in targeted neuronal delivery that need to be overcome for these promising therapeutics to move from the bench to the bedside.This work was financially supported by the project PTDC/CTM-NAN/3547/2014
(POCI-01-0145-FEDER-016639) funded by FEDER funds through the Programa Operacional Competitividade
e Internacionalização-COMPETE 2020 and Portuguese funds through FCT–Fundação para a Ciência e a
Tecnologia. A.P.S., B.C. and S.D.S. acknowledge FCT for the Ph.D. scholarships (SFRH/BD/137073/2018 and
SFRH/BD/145652/2019) and the contract under the Norma Transitória–DL57/2016/CP/CP1360/CT0013, respectively.
V.L. acknowledges her contract in the framework of the project NORTE-01-0247-FEDER-033399, funded by
FEDER funds through the Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico (SI I&DT), Aviso
nº 03/SI/2017, Projetos em Co-promoção do Programa Interfac
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