981 resultados para State-dependent


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“Dependent adult” abuse allegations involve people who are aged 18 or over and are incapable of adequate self care due to physical or mental conditions and require assistance from other people. Dependent adults may be elderly or may have diminished physical or mental capacities that prevent them from meeting their own needs adequately. Researchers estimate that only 1 in 14 incidents of elder abuse actually come to the attention of law enforcement or human service agencies. Elder abuse is one of the most under-recognized and under-reported social problems in the United States. It is far less likely to be reported than child abuse because of the lack of public awareness. Nationally, it is estimated that over 55% of elder abuse is due to self-neglect. Such abuse can happen anywhere … in private homes, at health care facilities and in the community at large. Iowa has an increasing proportion of people who are aged 60 or over. The number of persons 80 or over is increasing more rapidly than any other age group. Iowa’s proportion of older adults in the population exceeds that of the United States as a whole.

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Cette thèse présente la découverte de nouveaux inhibiteurs de l’amidotransférase ARNt-dépendante (AdT), et résume les connaissances récentes sur la biosynthèse du Gln-ARNtGln et de l’Asn-ARNtAsn par la voie indirecte chez la bactérie Helicobacter pylori. Dans le cytoplasme des eucaryotes, vingt acides aminés sont liés à leur ARNt correspondant par vingt aminoacyl-ARNt synthétases (aaRSs). Ces enzymes sont très spécifiques, et leur fonction est importante pour le décodage correct du code génétique. Cependant, la plupart des bactéries, dont H. pylori, sont dépourvues d’asparaginyl-ARNt synthétase et/ou de glutaminyl-ARNt synthétase. Pour former le Gln-ARNtGln, H. pylori utilise une GluRS noncanonique nommée GluRS2 qui glutamyle spécifiquement l’ARNtGln ; ensuite, une AdT trimérique, la GatCAB corrige le Glu-ARNtGln mésapparié en le transamidant pour former le Gln-ARNtGln, qui lira correctement les codons glutamine pendant la biosynthèse des protéines sur les ribosomes. La formation de l’Asn-ARNtAsn est similaire à celle du Gln-ARNtGln, et utilise la même GatCAB et une AspRS non-discriminatrice. Depuis des années 2000, la GatCAB est considérée comme une cible prometteuse pour le développement de nouveaux antibiotiques, puisqu’elle est absente du cytoplasme de l’être humain, et qu’elle est encodée dans le génome de plusieurs bactéries pathogènes. Dans le chapitre 3, nous présentons la découverte par la technique du « phage display » de peptides cycliques riches en tryptophane et en proline, et qui inhibent l’activité de la GatCAB de H. pylori. Les peptides P10 (CMPVWKPDC) et P9 (CSAHNWPNC) inhibent cette enzyme de façon compétitive par rapport au substrat Glu-ARNtGln. Leur constante d’inhibition (Ki) est 126 μM pour P10, et 392 μM pour P9. Des modèles moléculaires ont montré qu’ils lient le site actif de la réaction de transmidation catalysée par la GatCAB, grâce à la formation d’une interaction π-π entre le résidu Trp de ces peptides et le résidu Tyr81 de la sous-unité GatB, comme fait le A76 3’-terminal de l’ARNt. Dans une autre étude concernant des petits composés contenant un groupe sulfone, et qui mimiquent l’intermédiaire de la réaction de transamidation, nous avons identifié des composés qui inhibent la GatCAB de H. pylori de façon compétitive par rapport au substrat Glu-ARNtGln. Cinq fois plus petits que les peptides cycliques mentionnés plus haut, ces composés inhibent l’activité de la GatCAB avec des Ki de 139 μM pour le composé 7, et de 214 μM pour le composé 4. Ces inhibiteurs de GatCAB pourraient être utiles pour des études mécanistiques, et pourraient être des molécules de base pour le développement de nouvelles classes d’antibiotiques contre des infections causées par H. pylori.

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Rationale: Hospital malnutrition is a global health problem affecting 30-50% of hospitalized patients. There are no estimates of the size of this problem in Ecuadorian hospitals. Hospital malnutrition might influence the quality of medical assistance provided to hospitalized populations. Objectives: To estimate the current frequency of malnutrition among patients admitted to Ecuadorian public hospitals. Materials and methods: The Ecuadorian Hospital Malnutrition Study was conducted between November 2011 and June 2012 with 5,355 patients (Women. 37.5%; Ages ≥ 60 years. 35.1%; Length of stay ≤ 15 days. 91.2%) admitted to 36 public hospitals located in the prominent cities of 22 out of the 24 provinces of the country. Malnutrition frequency was estimated by means of the Subjective Global Assessment survey. Results: Malnutrition affected 37.1% of the surveyed patients. Malnutrition was dependent upon patient's age and education level; as well as the presence of cancer, sepsis, and chronic organic failure. Hospital areas showed different frequencies of hospital malnutrition. Health condition leading to hospital admission influenced negatively upon nutritional status. Malnutrition frequency increased as length of stay prolonged. Conclusions: Malnutrition currently affects an important proportion of patients hospitalized in public health institutions of Ecuador. Policies and actions are urgently required in order to successfully deal with this health problem and thus to ameliorate its negative impact upon quality of medical care

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In this paper we consider a class of scalar integral equations with a form of space-dependent delay. These non-local models arise naturally when modelling neural tissue with active axons and passive dendrites. Such systems are known to support a dynamic (oscillatory) Turing instability of the homogeneous steady state. In this paper we develop a weakly nonlinear analysis of the travelling and standing waves that form beyond the point of instability. The appropriate amplitude equations are found to be the coupled mean-field Ginzburg-Landau equations describing a Turing-Hopf bifurcation with modulation group velocity of O(1). Importantly we are able to obtain the coefficients of terms in the amplitude equations in terms of integral transforms of the spatio-temporal kernels defining the neural field equation of interest. Indeed our results cover not only models with axonal or dendritic delays but those which are described by a more general distribution of delayed spatio-temporal interactions. We illustrate the predictive power of this form of analysis with comparison against direct numerical simulations, paying particular attention to the competition between standing and travelling waves and the onset of Benjamin-Feir instabilities.

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Charge carrier lifetime measurements in bulk or unfinished photovoltaic (PV) materials allow for a more accurate estimate of power conversion efficiency in completed solar cells. In this work, carrier lifetimes in PV- grade silicon wafers are obtained by way of quasi-steady state photoconductance measurements. These measurements use a contactless RF system coupled with varying narrow spectrum input LEDs, ranging in wavelength from 460 nm to 1030 nm. Spectral dependent lifetime measurements allow for determination of bulk and surface properties of the material, including the intrinsic bulk lifetime and the surface recombination velocity. The effective lifetimes are fit to an analytical physics-based model to determine the desired parameters. Passivated and non-passivated samples are both studied and are shown to have good agreement with the theoretical model.

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Data files to accompany the article in Nature Communications, in press.

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The delicate balance between the production and disposal of proteins is vital for the changes required in the cell to respond to given stimulus. Ubiquitination is a protein modification with a range of signaling outcomes when ubiquitin is attached to a protein through a highly ordered enzymatic cascade process. Understanding ubiquitination is a growing field and nowadays the application of chemical reactions allows the isolation of quantitative materials for structural studies. Therefore, in this dissertation it is described some of these suitable chemical methodologies to produce an isopeptide bond toward the polymerization of ubiquitin bypassing the enzymatic control with the purpose of showing if these chemical modifications have a direct impact on the structure of ubiquitin. First, the possibility of incorporating non-natural lysine analogs known as mercaptolysines into the polypeptide chain of Ubiquitin was explored when they were attached to ubiquitin by native chemical ligation at its C terminus. The sulfhydryl group was used for the attachment of a paramagnetic label to map the surface of ubiquitin. Second, the condensation catalyzed by silver nitrate was used for the dimer assembly. In particular, the main focus was on examining whether orthogonal protection and deprotection of each monomer have an impact on the reaction yield, since the synthetic strategy has been previously attempted successfully. Third, the formation of ubiquitin dimers was approached by building an inter-ubiquitin linkage mimicking the isopeptide bond with two approaches, the classic disulfide exchange as well as the thiol-ene click reaction by thermal initiation in aqueous conditions. After assembling the dimeric units, they were studied by Nuclear Magnetic Resonance, in order to establish a conformational state profile which depends on the pH conditions. The latter is a very important concept since some ligands have a preferred affinity when the protein-protein hydrophobic patches are in close proximity.

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Despite major progress, currently available treatment options for patients suffering from schizophrenia remain suboptimal. Antipsychotic medication is one such option, and is helpful in acute phases of the disease. However, antipsychotics cause significant side-effects that often require additional medication, and can even trigger the discontinuation of treatment. Taken together, along with the fact that 20-30% of patients are medication-resistant, it is clear that new medical care options should be developed for patients with schizophrenia. Besides medication, an emerging option to treat psychiatric symptoms is through the use of neurofeedback. This technique has proven efficacy for other disorders and, more importantly, has also proven to be feasible in patients with schizophrenia. One of the major advantages of this approach is that it allows for the influence of brain states that otherwise would be inaccessible; i.e. the physiological markers underlying psychotic symptoms. EEG resting-state microstates are a very interesting electrophysiological marker of schizophrenia symptoms. Precisely, a specific class of resting-state microstates, namely microstate class D, has consistently been found to show a temporal shortening in patients with schizophrenia compared to controls, and this shortening is correlated with the presence positive psychotic symptoms. Under the scope of biological psychiatry, appropriate treatment of psychotic symptoms can be expected to modify the underlying physiological markers accompanying behavioral manifestations of a disease. We reason that if abnormal temporal parameters of resting-state microstates seem to be related to positive symptoms in schizophrenia, regulating this EEG feature might be helpful as a treatment for patients. The goal of this thesis was to prove the feasibility of microstate class D contribution self-regulation via neurofeedback. Given that no other study has attempted to regulate microstates via neurofeedback, we first tested its feasibility in a population of healthy subjects. In the first paper we describe the methodological characteristics of the neurofeedback protocol and its implementation. Neurofeedback performance was assessed by means of linear mixed effects modeling, which provided a complete profile of the neurofeedback’s training response within and between-subjects. The protocol included 20 training sessions, and each session contained three conditions: baseline (resting-state) and two active conditions: training (auditory feedback upon self-regulation performance) and transfer (self-regulation with no feedback). With linear modeling we obtained performance indices for each of them as follows: baseline carryover (baseline increments time-dependent) and learning and aptitude for each of the active conditions. Learning refers to the increase/decrease of the microstate class D contribution, time-dependent during each active condition, and aptitude refers to the constant difference of the microstate class D contribution between each active condition and baseline independent of time. The indices provided are discussed in terms of tailoring neurofeedback treatment to individual profiles so that it can be applied in future studies or clinical practice. In our sample of participants, neurofeedback proved feasible, as all participants at least showed positive results in one of the aforementioned learning indices. Furthermore, between-subjects we observed that the contribution of microstate class D across-sessions increased by 0.42% during baseline, 1.93% during training trials, and 1.83% during transfer. This range is expected to be effective in treating psychotic symptoms in patients. In the second paper presented in this thesis, we explored the possible predictors of neurofeedback success among psychological variables measured with questionnaires. An interesting finding was the negative correlation between “motivational incongruence” and some of the neurofeedback performance indices. Even though this finding requires replication, we discuss it in terms of the interfering effects of incompatible psychological processes with neurofeedback training requirements. In the third paper, we present a meta-analysis on all available studies that have related resting-state microstate abnormalities and schizophrenia. We obtained medium effect sizes for two microstate classes, namely C and D. Combining the meta-analysis results with the fact that microstate class D abnormalities are correlated with the presence of positive symptoms in patients with schizophrenia, these results add further support for the training of this precise microstate. Overall, the results obtained in this study encourage the implementation of this protocol in a population of patients with schizophrenia. However, future studies will have to show whether patients will be able to successfully self-regulate the contribution of microstate class D and, if so, whether this regulation will have an impact on symptomatology.

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Hydrogen is considered as an appealing alternative to fossil fuels in the pursuit of sustainable, secure and prosperous growth in the UK and abroad. However there exists a persisting bottleneck in the effective storage of hydrogen for mobile applications in order to facilitate a wide implementation of hydrogen fuel cells in the fossil fuel dependent transportation industry. To address this issue, new means of solid state chemical hydrogen storage are proposed in this thesis. This involves the coupling of LiH with three different organic amines: melamine, urea and dicyandiamide. In principle, thermodynamically favourable hydrogen release from these systems proceeds via the deprotonation of the protic N-H moieties by the hydridic metal hydride. Simultaneously hydrogen kinetics is expected to be enhanced over heavier hydrides by incorporating lithium ions in the proposed binary hydrogen storage systems. Whilst the concept has been successfully demonstrated by the results obtained in this work, it was observed that optimising the ball milling conditions is central in promoting hydrogen desorption in the proposed systems. The theoretical amount of 6.97 wt% by dry mass of hydrogen was released when heating a ball milled mixture of LiH and melamine (6:1 stoichiometry) to 320 °C. It was observed that ball milling introduces a disruption in the intermolecular hydrogen bonding network that exists in pristine melamine. This effect extends to a molecular level electron redistribution observed as a function of shifting IR bands. It was postulated that stable phases form during the first stages of dehydrogenation which contain the triazine skeleton. Dehydrogenation of this system yields a solid product Li2NCN, which has been rehydrogenated back to melamine via hydrolysis under weak acidic conditions. On the other hand, the LiH and urea system (4:1 stoichiometry) desorbed approximately 5.8 wt% of hydrogen, from the theoretical capacity of 8.78 wt% (dry mass), by 270 °C accompanied by undesirable ammonia and trace amount of water release. The thermal dehydrogenation proceeds via the formation of Li(HN(CO)NH2) at 104.5 °C; which then decomposes to LiOCN and unidentified phases containing C-N moieties by 230 °C. The final products are Li2NCN and Li2O (270 °C) with LiCN and Li2CO3 also detected under certain conditions. It was observed that ball milling can effectively supress ammonia formation. Furthermore results obtained from energetic ball milling experiments have indicated that the barrier to full dehydrogenation between LiH and urea is principally kinetic. Finally the dehydrogenation reaction between LiH and dicyandiamide system (4:1 stoichiometry) occurs through two distinct pathways dependent on the ball milling conditions. When ball milled at 450 RPM for 1 h, dehydrogenation proceeds alongside dicyandiamide condensation by 400 °C whilst at a slower milling speed of 400 RPM for 6h, decomposition occurs via a rapid gas desorption (H2 and NH3) at 85 °C accompanied by sample foaming. The reactant dicyandiamide can be generated by hydrolysis using the product Li2NCN.

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Nephrops norvegicus is a sedentary bottom-dwelling crustacean that represents one of the main commercial species exploited in the Adriatic Sea (Central Mediterranean). An evaluation of the status of this important resource is thus extremely important in order to manage it in a sustainable way. The evaluation of N. norvegicus is complicated by several issues, mainly: (i) the complex biology and behaviour of the species itself, (ii) the presence of subpopulations with different biological traits within the same stock unit. Relevant concentration of N.norvegicus occurs within the Pomo/Jabuka Pits area which is characterised by peculiar oceanographic and geophysical conditions. This area represented for a long time an important fishing ground shared by Italian and Croatian fleets and recently a Fishery Restricted Area (FRA) was established there. The aim of the present study is to perform for the first time an evaluation of the status of the N.norvegicus subpopulation inhabiting the Pomo/Jabuka Pits also accounting for the possible effects on it of the management measures. To achieve this, the principal fisheryindependent and fishery-dependent dataset available for the study area were firstly analysed and then treated. Data collected by the CNR-IRBIM of Ancona through both indirect (“UWTV”) and direct (trawling) methods were refined by means of a revision of the time series and related biases, and a modelling approach accounting for environmental and fishery effects, respectively. Commercial data for both Italy and Croatia were treated in order to obtain landings and length distributions for the Pomo area only; an historical reconstruction of data starting from 1970 was carried out for both countries. The obtained information was used as input for a Bayesian length-based stock assessment model developed through the CASAL software; the flexibility of this model is recommended for N.norvegicus and similar species allowing to deal with sex- and fleet-based integrated assessment method

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The research project is focused on the investigation of the polymorphism of crystalline molecular material for organic semiconductor applications under non-ambient conditions, and the solid-state characterization and crystal structure determination of the different polymorphic forms. In particular, this research project has tackled the investigation and characterization of the polymorphism of perylene diimides (PDIs) derivatives at high temperatures and pressures, in particular N,N’-dialkyl-3,4,9,10-perylendiimide (PDI-Cn, with n = 5, 6, 7, 8). These molecules are characterized by excellent chemical, thermal, and photostability, high electron affinity, strong absorption in the visible region, low LUMO energies, good air stability, and good charge transport properties, which can be tuned via functionalization; these features make them promising n-type organic semiconductor materials for several applications such as OFETs, OPV cells, laser dye, sensors, bioimaging, etc. The thermal characterization of PDI-Cn was carried out by a combination of differential scanning calorimetry, variable temperature X-ray diffraction, hot-stage microscopy, and in the case of PDI-C5 also variable temperature Raman spectroscopy. Whereas crystal structure determination was carried out by both Single Crystal and Powder X-ray diffraction. Moreover, high-pressure polymorphism via pressure-dependent UV-Vis absorption spectroscopy and high-pressure Single Crystal X-ray diffraction was carried out in this project. A data-driven approach based on a combination of self-organizing maps (SOM) and principal component analysis (PCA) is also reported was used to classify different π-stacking arrangements of PDI derivatives into families of similar crystal packing. Besides the main project, in the framework of structure-property analysis under non-ambient conditions, the structural investigation of the water loss in Pt- and Pd- based vapochromic potassium/lithium salts upon temperature, and the investigation of structure-mechanical property relationships in polymorphs of a thienopyrrolyldione endcapped oligothiophene (C4-NT3N) are reported.

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Ochnaceae s.str. (Malpighiales) are a pantropical family of about 500 species and 27 genera of almost exclusively woody plants. Infrafamilial classification and relationships have been controversial partially due to the lack of a robust phylogenetic framework. Including all genera except Indosinia and Perissocarpa and DNA sequence data for five DNA regions (ITS, matK, ndhF, rbcL, trnL-F), we provide for the first time a nearly complete molecular phylogenetic analysis of Ochnaceae s.l. resolving most of the phylogenetic backbone of the family. Based on this, we present a new classification of Ochnaceae s.l., with Medusagynoideae and Quiinoideae included as subfamilies and the former subfamilies Ochnoideae and Sauvagesioideae recognized at the rank of tribe. Our data support a monophyletic Ochneae, but Sauvagesieae in the traditional circumscription is paraphyletic because Testulea emerges as sister to the rest of Ochnoideae, and the next clade shows Luxemburgia+Philacra as sister group to the remaining Ochnoideae. To avoid paraphyly, we classify Luxemburgieae and Testuleeae as new tribes. The African genus Lophira, which has switched between subfamilies (here tribes) in past classifications, emerges as sister to all other Ochneae. Thus, endosperm-free seeds and ovules with partly to completely united integuments (resulting in an apparently single integument) are characters that unite all members of that tribe. The relationships within its largest clade, Ochnineae (former Ochneae), are poorly resolved, but former Ochninae (Brackenridgea, Ochna) are polyphyletic. Within Sauvagesieae, the genus Sauvagesia in its broad circumscription is polyphyletic as Sauvagesia serrata is sister to a clade of Adenarake, Sauvagesia spp., and three other genera. Within Quiinoideae, in contrast to former phylogenetic hypotheses, Lacunaria and Touroulia form a clade that is sister to Quiina. Bayesian ancestral state reconstructions showed that zygomorphic flowers with adaptations to buzz-pollination (poricidal anthers), a syncarpous gynoecium (a near-apocarpous gynoecium evolved independently in Quiinoideae and Ochninae), numerous ovules, septicidal capsules, and winged seeds with endosperm are the ancestral condition in Ochnoideae. Although in some lineages poricidal anthers were lost secondarily, the evolution of poricidal superstructures secured the maintenance of buzz-pollination in some of these genera, indicating a strong selective pressure on keeping that specialized pollination system.

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Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the hidden order (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

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The present study investigated the effects of running at 0.8 or 1.2 km/h on inflammatory proteins (i.e., protein levels of TNF- α , IL-1 β , and NF- κ B) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1 α , and AMPK phosphorylation) in quadriceps of rats. Male Wistar rats at 3 (young) and 18 months (middle-aged rats) of age were divided into nonexercised (NE) and exercised at 0.8 or 1.2 km/h. The rats were trained on treadmill, 50 min per day, 5 days per week, during 8 weeks. Forty-eight hours after the last training session, muscles were removed, homogenized, and analyzed using biochemical and western blot techniques. Our results showed that: (a) running at 0.8 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with NE rats; (b) these responses were lower for the inflammatory proteins and higher for the metabolic proteins in young rats compared with middle-aged rats; (c) running at 1.2 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with 0.8 km/h; (d) these responses were similar between young and middle-aged rats when trained at 1.2 km. In summary, the age-related increases in inflammatory proteins, and the age-related declines in metabolic proteins can be reversed and largely improved by treadmill training.