859 research outputs found
Reconstitution of the dynamic microtubule and kinetochore interface
During mitosis, genetic integrity of eukaryotic cells is critically dependent on the capture and stable attachment of microtubules (MTs) to the kinetochores. Kinetochores and MTs can be both regarded as nanodevices that interact and are able to create a machine capable of moving bulky objects such as chromosomes during cell division. Many of the MTs activities are mediated by interaction with a large number of microtubule associated proteins (MAPs), but knowledge is still fragmentary about how these proteins are involved and how the process is spatially and temporarily regulated within the cells. Poisons that affect MT function have been identified. Some, but not all, of these compounds, have clinical utility as anti-cancer drugs. Understanding the molecular mechanisms subtending to the function of microtubules and associated proteins is important to identify and characterize new molecular targets in anti-cancer therapy. The MT plus end is the contact surface between MTs and kinetochores, and to date, several associating proteins called +TIPs were identified as being specifically binding the microtubule plus end. We will investigate the interactions of +TIPs such as CLIP170 and EB1 with the Ndc80 complex, a constituent of the outer kinetochore that has recently emerged as a direct point of contact between kinetochores and microtubules.
The aim of the project will be to reconstitute in vitro, in part or entirely, a human MT-kinetochore complex interface and try to unveil the molecular mechanisms involved in the interactions between MTs and kinetochores
A novel enzymatically-mediated drug delivery carrier for bone tissue engineering applications: combining biodegradable starch-based microparticles and differentiation agents
In many biomedical applications, the performance
of biomaterials depends largely on their degradation
behavior. For instance, in drug delivery applications, the
polymeric carrier should degrade under physiological
conditions slowly releasing the encapsulated drug. The aim
of this work was, therefore, to develop an enzymaticmediated
degradation carrier system for the delivery of
differentiation agents to be used in bone tissue engineering
applications. For that, a polymeric blend of starch with
polycaprolactone (SPCL) was used to produce a microparticle
carrier for the controlled release of dexamethasone
(DEX). In order to investigate the effect of enzymes on the
degradation behavior of the developed system and release
profile of the encapsulated osteogenic agent (DEX), the
microparticles were incubated in phosphate buffer solution
in the presence of a-amylase and/or lipase enzymes (at
physiological concentrations), at 37 C for different periods
of time. The degradation was followed by gravimetric
measurements, scanning electron microscopy (SEM) and
Fourier transformed infrared (FTIR) spectroscopy and the
release of DEX was monitored by high performance liquid
chromatography (HPLC). The developed microparticles
were shown to be susceptible to enzymatic degradation, as observed by an increase in weight loss and porosity with
degradation time when compared with control samples
(incubation in buffer only). For longer degradation times,
the diameter of the microparticles decreased significantly
and a highly porous matrix was obtained. The in vitro
release studies showed a sustained release pattern with
48% of the encapsulated drug being released for a period of
30 days. As the degradation proceeds, it is expected that
the remaining encapsulated drug will be completely
released as a consequence of an increasingly permeable
matrix and faster diffusion of the drug. Cytocompatibility
results indicated the possibility of the developed microparticles
to be used as biomaterial due to their reduced
cytotoxic effects
Three dimensional corrugated organic photovoltaics for building integration; improving the efficiency, oblique angle and diffuse performance of solar cells
The lamination of OPV modules to corrugated roof cladding has been undertaken. The 3-dimensional form of the cladding provides three advantages for outdoor OPV deployment; firstly the âfootprintâ of the solar cell is reduced, which leads to âŒ10% improved power conversion (PCE) efficiency per unit area. Secondly, the oblique angle performance is enhanced, leading to increased output in the early morning and evening. Indoor characterisation showed a 9-fold enhancement in efficiency was obtainable, when compared to a flat module. Thirdly, an improvement in performance under diffuse lighting conditions was measured, when compared to a flat module. The average daily yield of the 3D module was 17â29% higher than a flat module, with higher relative enhancements observed on cloudier days. Geographically, the 3D module appears to be well-suited to countries with a high latitude, due to the enhanced diffuse light levels and the fact that tilting the module in both âlatitudeâ and âlongitudeâ directions away from normal, leads to the best achievable enhancement in solar cell performance. The approach set out in this paper could yield a product that has profound advantages over existing BIPV products and is potentially applicable to other flexible inorganic solar cell technologies
Isolation of Salmonella enterica in opossum (Didelphis aurita and Didelphis albiventris) of the SĂŁo Paulo State, Brazil
No Brasil, nĂŁo hĂĄ relato de estudos de Salmonella em gambĂĄs, sendo assim, este trabalho tem por objetivo determinar a frequĂȘncia de isolamento de Salmonella enterica em gambĂĄs (D. aurita e D. albiventris) no Estado de SĂŁo Paulo. No perĂodo de janeiro de 2005 a dezembro de 2006, foram necropsiados 106 D. aurita e 40 D. albiventris e colhidos fragmentos de intestinos delgado, grosso e suabe da cloaca. As amostras foram plaqueadas diretamente em ĂĄgar Mac Conkey, paralelamente suspendidas nos caldos Rappaport-Vassiliadis e Tetrationato e posteriormente plaqueados em ĂĄgar XLT4. As colĂŽnias sugestivas de Salmonella foram confirmadas atravĂ©s de provas bioquĂmicas e sorotipagem. Encontrou-se Salmonella enterica em 17,0% (18/106) dos D. aurita. Destes, 50% apresentaram positividade no intestino delgado (ID), 88,9% no intestino grosso (IG) e 66,7% na cloaca. Da espĂ©cie S. enterica, as subespĂ©cies encontradas foram: diarizonae (11,1%) houtenae e enterica (5,5% cada um); enquanto da subespĂ©cie S. enterica enterica os sorotipos foram Newport (83,3%), Typhimurium e Cerro (5,5% cada um). Nos D. albiventris, 17,5% (7/40) eram positivos, sendo que se encontraram 42,8% no ID, 85,7% no IG e 71,4% na cloaca. O sorotipo mais prevalente tambĂ©m foi Newport (71,4%), seguido por Typhimurium, Bareilly e Thompson (14,3% cada um). AtravĂ©s dos resultados obtidos neste estudo pode-se comprovar a presença de Salmonella enterica no trato intestinal de gambĂĄs no Brasil.In Brazil there is not report of Salmonella in opossum, so then, the objective of this study is to determine the isolation frequency of Salmonella enterica in opossum in SĂŁo Paulo State, Brazil. From January 2005 to December 2006, 106 D. aurita and 40 D. albiventris were necropsied and samples from small and large intestine and cloacal swab were collected. These samples were submitted to direct plating in Mac Conkey agar and parallel suspension in Rappaport-Vassiliadis and Tetrationate broths with posterior streaking in XLT4 agar. The characterization of the isolates was done through biochemical tests and serotyping. Salmonella enterica was found in 17.0% (18/106) of the D. aurita; 50% presented the bacteria in the small intestine (SI), 88.9% in the large intestine (LI) and 66.7% in the cloaca. Of the S. enterica were found the subspecies: diarizonae (11.1%), enterica and houtenae (5.5% each); and the serotypes of the S. enterica enterica were Newport (83.3%), Typhimurium and Cerro (5.5% each). In the D. albiventris 17.5% (7/40) were positive; 42.8% in the SI, 85.7% in the LI and 71.4% in the cloaca. Newport (71.4%) was also the most frequent serotype and the second were Typhimurium, Bareilly and Thompson (14.3% each). The presence of Salmonella enterica in the intestines of opossums in Brazil was proved
Controlled release strategies for bone, cartilage, and osteochondral engineering: part I: recapitulation of native tissue healing and variables for the design of delivery systems
The potential of growth factors to stimulate tissue healing through the enhancement of cell proliferation, migration, and differentiation is undeniable. However, critical parameters on the design of adequate carriers, such as uncontrolled spatiotemporal presence of bioactive factors, inadequate release profiles, and supraphysiological dosages of growth factors, have impaired the translation of these systems onto clinical practice. This review describes the healing cascades for bone, cartilage, and osteochondral interface, highlighting the role of specific growth factors for triggering the reactions leading to tissue regeneration. Critical criteria on the design of carriersfor controlled release of bioactive factors are also reported, focusing on the need to provide a spatiotemporal control over the delivery and presentation of these molecules.The authors thank Fundacao para a Ciencia e Tecnologia for V.E.Santo's PhD grant (SFRH/BD/39486/2007). This work was carried out under the scope of the European FP7 Project Find and Bind (NMP4-SL-2009-229292) and Project MIT/ECE/0047/2009
Qualidade sanitĂĄria e fisiolĂłgica de sementes de abĂłbora variedade menina Brasileira.
O trabalho teve como objetivos avaliar e correlacionar a qualidade sanitĂĄria e fisiolĂłgica de sementes de abĂłbora, variedade Menina Brasileira (Cucurbita moschata.). Foram avaliados dois lotes de sementes de abĂłbora produzidas no sistema agroecolĂłgico e quatro no sistema convencional, com e sem tratamento quĂmico. Os lotes foram submetidos aos testes de sanidade, seguindo a metodologia do âBlotter testâ, com congelamento, germinação e vigor (primeira contagem, Ăndice de velocidade de germinação, envelhecimento acelerado e emergĂȘncia de plĂąntulas). Os resultados indicaram a separação dos lotes de diferentes origens a partir da qualidade sanitĂĄria e fisiolĂłgica, onde as maiores incidĂȘncias de fungos foram observadas nos lotes agroecolĂłgicos e o maior potencial fisiolĂłgico foi observado nos lotes de origem convencional nĂŁo tratados. Foram encontrados os fungos Fusarium oxysporum, Alternaria alternata, Cladosporium cucumerinum, Aspergillus niger, Penicillium digitatum, Rhizopus stolonifer e Phoma terrestris. A qualidade sanitĂĄria nĂŁo interferiu na qualidade fisiolĂłgica das sementes de abĂłbora, variedade Menina Brasileira
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Model-independent search for CP violation in D0âKâK+ÏâÏ+ and D0âÏâÏ+Ï+Ïâ decays
A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states KâK+ÏâÏ+ and ÏâÏ+Ï+Ïâ is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fbâ1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the KâK+ÏâÏ+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the ÏâÏ+Ï+Ïâ final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
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