1,523 research outputs found
Does neurocognitive training have the potential to improve dietary self-care in type 2 diabetes? Study protocol of a double blind randomised controlled trial
Dietary self-care is a key element of self-management in type 2 diabetes. It is also the most difficult aspect of diabetes self-management. Adhering to long-term dietary goals and resisting immediate food desires requires top-down inhibitory control over subcortical impulsive and emotional responses to food. Practising simple neurocognitive tasks can improve inhibitory control and health behaviours that depend on inhibitory control, such as resisting alcohol consumption. It is yet to be investigated, however, whether neurocognitive training can improve dietary self-care in people with type 2 diabetes. The aim of this randomised controlled trial is to investigate whether web-based neurocognitive training can improve the ability of people with type 2 diabetes to resist tempting foods and better adhere to a healthy dietary regime
Novel time-domain methods for free-running oscillators
A novel time-domain method for finding the periodic steady-state of a free-running electrical oscillator is introduced. The method is based on the extrapolation technique MPE. This method is applied to the well-known Colpitt's Oscillator, for which it turns out to have super-linear convergence
Using Galvanic Vestibular Stimulation to Induce Post-Roll Illusion in a Fixed-Base Flight Simulator
INTRODUCTION: The illusions of head motion induced by galvanic vestibular stimulation (GVS) can be used to compromise flight performance of pilots in fixed-base simulators. However, the stimuli used in the majority of studies fail to mimic disorientation in realistic flight because they are independent from the simulated aircraft motion. This study investigated the potential of bilateral-bipolar GVS coupled to aircraft roll in a fixed-base simulator to mimic vestibular spatial disorientation illusions, specifically the âpost-roll illusionâ observed during flight.METHODS: There were 14 nonpilot subjects exposed to roll stimuli in a flight simulator operating in a fixed-base mode. GVS was delivered via carbon rubber electrodes on the mastoid processes. The electrical stimulus was driven by the high-pass filtered aircraft roll rate to mimic the semicircular canalsâ physiological response. The post-roll test scenarios excluded outside visual cues or instruments and required subjects to actively maintain a constant bank angle after an abrupt stop following a passive prolonged roll maneuver. The anticipated outcome was an overshot in roll elicited by the GVS signal. RESULTS: The responses across subjects showed large variability, with less than a third aligning with the post-roll illusion. Subjective ratings suggest that the high-pass filtered GVS stimuli were mild and did not induce a clear sense of roll direction. However, uncontrolled head movements during stimulation might have obscured the intended effects of GVS-evoked illusory head movements. CONCLUSION: The mild and transient GVS stimuli used in this study, together with the uncontrolled head movements, did not convincingly mimic the post-roll illusion.</p
Does working memory training improve dietary self-care in type 2 diabetes mellitus? Results of a double blind randomised controlled trial
Aims: Controlling food intake despite adequate knowledge remains a struggle for many people with type 2 diabetes. The present study investigated whether working memory training can reduce food intake and improve glycaemic control. It also examined training effects on cognition, food cravings, and dietary self-efficacy and self-care.
Methods: In a double-blind multicentre parallel-group randomised controlled trial, adults with type 2 diabetes mellitus were randomly allocated to receive 25 sessions of either active (n = 45) or control (n = 36) working memory training. Assessments at baseline, post-training and 3-month follow-up measured cognition, food intake (primary outcomes), glycaemic control (HbA1c) and cholesterol (secondary outcomes). Semi-structured interviews assessed participantsâ experiences of the training.
Results: Intention-to-treat ANOVAs (N = 81) showed improved non-trained updating ability in active compared to control training from pre-test (active M = 34.37, control M = 32.79) to post-test (active M = 31.35, control M = 33.53) and follow-up (active M = 31.81, control M = 32.65; g2 = 0.05). There were no overall effects of training on other measures of cognition, food intake, HbA1c, cholesterol, food cravings and dietary self-efficacy and self-care. In post-hoc analyses, those high in dietary restraint in the active training group showed a greater reduction in fat intake pre to post-test compared to controls. Interviews revealed issues around acceptability and performance of the training.
Conclusions: Transfer of working memory training effects to non-trained behaviour were limited, but do suggest that training may reduce fat intake in those who are already motivated to do so.
Trial registration: Current Controlled Trials ISRCTN22806944
Line Defects in Molybdenum Disulfide Layers
Layered molecular materials and especially MoS2 are already accepted as
promising candidates for nanoelectronics. In contrast to the bulk material, the
observed electron mobility in single-layer MoS2 is unexpectedly low. Here we
reveal the occurrence of intrinsic defects in MoS2 layers, known as inversion
domains, where the layer changes its direction through a line defect. The line
defects are observed experimentally by atomic resolution TEM. The structures
were modeled and the stability and electronic properties of the defects were
calculated using quantum-mechanical calculations based on the
Density-Functional Tight-Binding method. The results of these calculations
indicate the occurrence of new states within the band gap of the semiconducting
MoS2. The most stable non-stoichiometric defect structures are observed
experimentally, one of which contains metallic Mo-Mo bonds and another one
bridging S atoms
Optimisation de la réaction de Suzuki-Miyaura dans une perspective de synthÚse de librairies de peptides
La transcription des symboles et des caractĂšres spĂ©ciaux utilisĂ©s dans la version originale de ce rĂ©sumĂ© nâa pas Ă©tĂ© possible en raison de limitations techniques. La version correcte de ce rĂ©sumĂ© peut ĂȘtre lue en PDF.
L'utilisation de peptides en tant qu'agents thérapeutiques présente plusieurs avantages. En effet, les peptides sont des molécules qui possÚdent une haute affinité et spécificité tout en ayant un profil de toxicité plus bas que la plupart des petites molécules pharmacologiques. De plus, contrairement aux protéines, les peptides sont plus stables aux variations de température et ils possÚdent une meilleure pénétration des tissus à cause de leur taille relativement petite. Par contre, leur utilisation est encore limitée. Pour augmenter la spécificité et l'affinité de récepteur, la stabilité sanguine aussi bien que la puissance des peptides, on a fait des modifications chimiques y compris l'introduction de groupements aromatiques, de fonctions hétérocycliques ou de petits fragments de molécule sur la chaßne peptidique. à cet égard, la réaction de Suzuki-Miyaura (SM) s'avÚre appropriée pour la modification des peptides.
La réaction de SM est le couplage entre un dérivé de l'acide boronique et un halogénure ou un triflate de vinyle ou d'aryle en présence d'un catalyseur de palladium et d'une base. Les principaux avantages de cette réaction sont des conditions de réaction douces, une toxicité moindre pour l'environnement par rapport à la plupart des autres réactifs organométalliques, et la disponibilité commerciale des dérivés de l'acide boronique. Présentement, la réaction de SM est fréquemment utilisée en synthÚse organique classique et elle a contribué à accélérer la préparation de composés bioactifs pour des études structure-activité. Toutefois, son usage est toujours trÚs limité pour la conception de dérivés peptidiques et en particulier la réaction n'a jamais été exploitée pour la modification post-synthÚse aprÚs assemblage d'une chaßne peptidique sur un support solide. Puisque les peptides contiennent des groupements actifs qui pourraient interférer avec la réaction de SM, il nous est apparu plus approprié d'exécuter la réaction en phase solide tandis que tous les groupements des chaßnes latérales du peptide sont protégés.
Dans la présente étude, nous montrons une nouvelle stratégie utilisant la réaction de SM
pour modifier en phase solide des peptides contenant un acide aminé aromatique. Le peptide [Ala 1,2,3 , Leu8 ]Enk, lié à une résine de type Wang, a été choisi comme modÚle de peptide-résine afin de vérifier la compatibilité avec la méthode de SM.
Notre premier essai, effectué avec le N-a-Fmoc-[Ala 1,2,3 , Phe(pl)4 , Leu ]Enk, lié à une résine Wang, a indiqué que le groupement protecteur Fmoc n'est pas stable dans les conditions basiques utilisées pour la réaction de SM. Le groupement protecteur Fmoc a été ensuite remplacé par un groupe Boe et celui-ci s'est montré compatible avec la
méthode.
Afin d'Ă©valuer les conditions optimales de la rĂ©action de SM nous avons Ă©tudiĂ©, l'influence de la base, du solvant, du catalyseur, de la tempĂ©rature et du temps sur le rendement rĂ©actionnel. L'acide phĂ©nylboronique a Ă©tĂ© utilisĂ© pour cette optimisation. Les conditions optimales se sont avĂ©rĂ©es ĂȘtre le DMF comme solvant, le K3P04 ou le Na2C03
comme base et le Pd(PPh3)4 comme catalyseur, avec un temps de réaction de 20 h et une
température de l'ordre de 80 °C, nous avons poursuivi notre étude afin d'évaluer les rendements avec différents acides boroniques.
En particulier, l'étude a été étendue à l'analyse du comportement de la réaction de SM
lors de substitutions par divers acides boroniques contenant des groupements Ă©lectroÂ
donneurs ou électro-attracteurs. n semble que les dérivés de l'acide phénylboronique
porteurs d'un groupement électro-attracteur sur le cycle aromatique soient plus réactifs
que ceux avec un groupement électro-doneur. Par exemple, 1'acide 4- méthoxyphénylboronique a été complÚtement inactif dans ces conditions de réaction de SM, tandis que le couplage avec l'acide 4-méthylcarboxyphénylboronique a donné 87%
de conversion. Ces conditions ont également été appliquées en synthÚse de dérivés hétéroaromatiques de H2N-[Ala 1,2, 3, Leu8]Enk-OH. à cet égard, les dérivés de l'acide
pyridineboronique, l'acide furaneboronique, et l'acide thiophÚneboronique ont été utilisés et ils sont donné de bons rendements. Enfin, la réaction de SM avec des acides alkylboroniques a également été étudiée sur l'iodo-peptide-résine. Les résultats obtenus indiquent que l'acide trans-2-chlorométhylvinylboronique est facilement couplé tandis que l'acide 2-méthylvinylboronique donne seulement 10% de conversion. Des résultats
similaires ont été obtenus pour la modification en phase solide de N-a-Boc-[Ala 1,2,3 ,Leu8]Enk-résine à la position Phe7⹠Par contre, il semble qu'il y ait un encombrement stérique qui désavantage la réaction de SM lors de modifications à la position Phe7. En
effet, les conversions obtenues à cette position sont plus basses que celles observées lors des modifications effectuées en position Tyr4.
Ăgalement, une apprĂ©ciation plus globale de la stratĂ©gie nous est apparue nĂ©cessaire et c'est pourquoi des Ă©tudes additionnelles ont ensuite Ă©tĂ© poursuivies avec des peptides plus complexes, afin de vĂ©rifier la compatibilitĂ© de la mĂ©thode de SM avec des sĂ©quences de peptide contenant des acides aminĂ©s sensibles tels que la mĂ©thionine, la cystĂ©ine, l'histidine et le tryptophane. Pour ce faire, des peptides courts contenant les rĂ©sidus Cys, Met, His ou Trp ont Ă©tĂ© synthĂ©tisĂ©s. La rĂ©action s'est bien dĂ©roulĂ©e avec les peptides contenant Cys, Met ou His. Par contre, la prĂ©sence de Trp semble ĂȘtre problĂšmatique puisque le mĂ©lange de peptides aprĂšs la rĂ©action de SM ne contenait pas le peptide attendu. De plus, un peptide possĂ©dant une masse de 34 Da infĂ©rieure Ă celle du produit attendu a Ă©tĂ© froduit. Un rĂ©sultat similaire a Ă©galement Ă©tĂ© obtenu avec le peptide N-aÂ
Boc-[Phe(pl)13]ET-1(9-21). Ătant donnĂ© que la mĂȘme rĂ©action secondaire s'est produite en soumettant le peptide N-a-Boc-[BiP13]ET-1(9-21), il peut ĂȘtre conclu que cette perte
de masse s'effectue indĂ©pendemment de la prĂ©sence du rĂ©sidu Phe(pl). La nature et l'endroit oĂč se produit cette modification reste encore Ă Ă©lucider.
En conclusion le développement de conditions de la réaction de SM appropriées à toutes les séquences peptidiques est un objectif des plus importants afin d'augmenter les outils disponibles pour la modification post-synthÚse des peptides.</p
Merkel cell polyomavirus large T antigen disrupts lysosome clustering by translocating human Vam6p from the cytoplasm to the nucleus
Merkel cell polyomavirus (MCV) has been recently described as the cause for most human Merkel cell carcinomas. MCV is similar to simian virus 40 (SV40) and encodes a nuclear large T (LT) oncoprotein that is usually mutated to eliminate viral replication among tumor-derived MCV. We identified the hVam6p cytoplasmic protein involved in lysosomal processing as a novel interactor with MCV LT but not SV40 LT. hVam6p binds through its clathrin heavy chain homology domain to a unique region of MCV LT adjacent to the retinoblastoma binding site. MCV LT translocates hVam6p to the nucleus, sequestering it from involvement in lysosomal trafficking. A naturally occurring, tumor-derived mutant LT (MCV350) lacking a nuclear localization signal binds hVam6p but fails to inhibit hVam6p-induced lysosomal clustering. MCV has evolved a novel mechanism to target hVam6p that may contribute to viral uncoating or egress through lysosomal processing during virus replication
Anti-phosphorylated histone H2AThr120: A universal microscopic marker for centromeric chromatin of mono- and holocentric plant species
Based on the analysis of 20 different monocot and eudicot species, we propose that the centromeric distribution of the phosphorylated histone H2AThr120 is evolutionary highly conserved across species with mono- and holocentric chromosomes. Therefore, antibodies recognizing the phosphorylated threonine 120 of the histone H2A can serve as a universal marker for the cytological detection of centromeres of mono- and holokinetic plant species. In addition, super resolution microscopy of signals specific to the centromere-specific histone H3 variant CENH3 and to H2AThr120ph revealed that these histone variants are incorporated into different nucleosomes, which form distinct, partly intermingled chromatin domains. This specific arrangement of both histone variants suggests different centromeric functions during the cell cycle
Isolation and characterization of acetylated LM-pectins extracted from okra pods
Pectin was isolated by aqueous extraction at pH 6.0 or 2.0 from okra (Abelmoschus esculentus L.) pods. An isolation protocol was designed to extract pectin and to study the influence of the extraction pH on their composition and physicochemical properties. The extracted pectin was assessed using sugar compositional analysis (neutral sugars, galacturonic acid, acetyl and methyl contents). FT-IR and NMR spectroscopy, size exclusion chromatography (SEC) and dilute solution viscometry were also used to determine the macromolecular characteristics of isolated pectin. The extraction protocols resulted in the isolation of pectin of high purity as evidenced by their high total carbohydrate (70.0â81.8%) and low protein (4.3â6.3%) contents. Samples contained between 46 and 56% galacturonic acid, had broad molecular weight distributions, a low degree of methylation (40.0 and 24.6%) and high degree of acetylation (52.2 and 37.6%). Neutral sugar analysis showed that the pectin extracted at pH 6.0 contained more neutral sugars, particularly, galactose (21.7â25.7 mol%), rhamnose (10.1â13.2 mol%) and arabinose (7.1â7.3 mol%) than that extracted at pH 2.0 indicating variations in fine structure. In addition, molecular parameters of the isolated pectins, such as intrinsic viscosity (2.8â4.4 dL gâ1), critical concentration (0.15â0.45 dL gâ1) and coil overlap parameter (0.66â1.51), showed that extraction conditions resulted in pectin with different chain morphology. The yield and physico-chemical characteristics of the extracted pectin from okra pods were influenced by the extraction conditions
Numerical investigation of the in-plane seismic performance of unstrengthened and TRM-strengthened rammed earth walls
The large availability of raw earth around the World led to its extensive use as a building material through history. Thus, earthen materials integrate several historical monuments, but their main use was to build living and working environments for billions of people. On the other hand, past earthquakes revealed their inadequate seismic behavior, which is a matter of concern as a significant percentage of earthen buildings are located in regions with medium to high seismic hazard. Nevertheless, their seismic behavior and the development of efficient strengthening solutions are topics that are not yet sufficiently investigated in the literature. In this context, this study investigates numerically the in-plane seismic behavior of a rammed earth component by means of advanced nonlinear finite element modeling, which included performing nonlinear static (pushover) and nonlinear dynamic analyses. Moreover, the strengthening effectiveness of a low-cost textile-reinforced mortar on such component was also evaluated. The strengthening was observed to increase the load and displacement capacities, to preserve the integrity for higher lateral load levels and to postpone failure without adding significant mass to the system. Furthermore, the pushover analysis was shown to predict reliably the capacities of the models with respect to the incremental dynamic analysis.This work was financed by FEDER funds through the Competitively Factors Operational Programme (COMPETE) and by national funds through the Foundation for Science and Technology (FCT) within the scope of projects POCI-01-0145-FEDER-016737 (PTDC/ECM-EST/2777/2014) and POCI-01-0145-FEDER-007633. The support from grant SFRH/BPD/97082/2013 is also acknowledged
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