Layer-by-layer technique to developing functional nanolaminate films with antifungal activity

The layer-by-layer (LbL) deposition method was used to build up alternating layers (five) of different polyelectrolyte solutions (alginate, zein-carvacrol nanocapsules, chitosan and chitosan-carvacrol emulsions) on an aminolysed/charged polyethylene terephthalate (A/C PET) film. These nanolaminated films were characterised by contact angle measurements and through the determination of water vapour (WVTR) and oxygen (O2TR) transmission rates. The effect of active nanolaminated films against the Alternaria sp. and Rhizopus stolonifer was also evaluated. This procedure allowed developing optically transparent nanolaminated films with tuneable water vapour and gas properties and antifungal activity. The water and oxygen transmission rate values for the multilayer films were lower than those previously reported for the neat alginate or chitosan films. The presence of carvacrol and zein nanocapsules significantly decreased the water transmission rate (up to 40 %) of the nanolaminated films. However, the O2TR behaved differently and was only improved (up to 45 %) when carvacrol was encapsulated, i.e. nanolaminated films prepared by alternating alginate with nanocapsules of zein-carvacrol layers showed better oxygen barrier properties than those prepared as an emulsion of chitosan and carvacrol. These films containing zein-carvacrol nanocapsules also showed the highest antifungal activity (30 %), which did not significantly differ from those obtained with the highest amount of carvacrol, probably due to the controlled release of the active agent (carvacrol) from the zein-carvacrol nanocapsules. Thus, this work shows that nanolaminated films prepared with alternating layers of alginate and zein-carvacrol nanocapsules can be considered to improve the shelf-life of foodstuffs.

Mesenchymal stem cells secretome as a modulator of the neurogenic niche: Basic insights and therapeutic opportunities

Neural stem cells (NSCs) and mesenchymal stem cells (MSCs) share few characteristics apart from self-renewal and multipotency. In fact, the neurogenic and osteogenic stem cell niches derive from two distinct embryonary structures; while the later originates from the mesoderm, as all the connective tissues do, the first derives from the ectoderm. Therefore, it is highly unlikely that stem cells isolated from one niche could form terminally differentiated cells from the other. Additionally, these two niches are associated to tissues/systems (e.g., bone and central nervous system) that have markedly different needs and display diverse functions within the human body. Nevertheless they do share common features. For instance, the differentiation of both NSCs and MSCs is intimately associated with the bone morphogenetic protein family. Moreover, both NSCs and MSCs secrete a panel of common growth factors, such as nerve growth factor (NGF), glial derived neurotrophic factor (GDNF), and brain derived neurotrophic factor (BDNF), among others. But it is not the features they share but the interaction between them that seem most important, and worth exploring; namely, it has already been shown that there are mutually beneficially effects when these cell types are co-cultured in vitro. In fact the use of MSCs, and their secretome, become a strong candidate to be used as a therapeutic tool for CNS applications, namely by triggering the endogenous proliferation and differentiation of neural progenitors, among other mechanisms. Quite interestingly it was recently revealed that MSCs could be found in the human brain, in the vicinity of capillaries. In the present review we highlight how MSCs and NSCs in the neurogenic niches interact. Furthermore, we propose directions on this field and explore the future therapeutic possibilities that may arise from the combination/interaction of MSCs and NSCs.

Fontan Operation and the Cavopulmonary Technique: Immediate and Late Results According to the Presence of Atrial Fenestration

OBJECTIVE: To compare immediate and late results in patients with or without fenestration who underwent cavopulmonary anastomosis so that we could assess the efficiency of the technique. METHODS: Sixty-two patients underwent surgery between 1988 and 1999, 41 with fenestration (group I -G I) and 21 without fenestration (group II -G II). Tricuspid atresia was prevalent in group I (23-56%) and single ventricle was prevalent in group II (14-66%). Mean ages at the time of operation were 7.3 years in group I and 7.6 in group II. At late follow-up, mean ages were 10.6 years in group I and 12.8 years in group II. RESULTS: Immediate and late mortality were 7.3% in G-I and 4.7% in G-II. Significant pleural effusion occurred in 41.4% of G-I patients and in 23.8% of G-II patients. Significant pericardial effusion occurred in 29.2% and 14.2%, respectively, in groups I and II. Central venous pressure was greater in G-II, 17.7 cm in H2O, as opposed to 15 cm in G-I. Hospital stay was similar between the groups, 26.3 and 21.8 days, respectively. Cyanosis and arterial insaturation occurred in 5 patients, and 4 patients were in functional class II, all from G-I. At late follow-up, 58 (93.5%) were in functional class I. Sinus rhythm was present in 94%, and pulmonary perfusion was similar in both groups. Eleven patients who underwent spirometry had good tolerance to physical effort. CONCLUSION: Atrial fenestration did not improve the immediate or late follow-up of patients who underwent cavopulmonary anastomosis, and is, therefore, dispensable.

Using one-year claim development to chose a large claim reserving technique

Mestrado em Ciências Actuariais

Los objetos técnicos y los organismos tecnificados. Reflexiones filosóficas, estéticas y políticas sobre la técnica. Technical objects and technified organisms. Philosophical, aesthetical and political approaches on technique

El presente proyecto se propone como parte inicial de una investigación sobre la relación entre naturaleza/cultura/técnica. Tradicionalmente la naturaleza y la cultura se han considerado como ámbitos diferenciados y opuestos. Y es en esta distinción donde la técnica adquiere un lugar central. El pensamiento occidental sobre la técnica ha recibido diversas interpretaciones: desde una subordinación con respecto al conocimiento verdadero (episteme) en la filosofía clásica, un optimismo sobre la técnica como posibilidad de dominación de la naturaleza en el Renacimiento y la Ilustración, y la ambigüedad y desasosiego romántico (Mitcham, 1979). Durante el siglo XX se distinguen dos posiciones antagónicas sobre la técnica. Por un lado, una actitud “crítica” donde pueden identificarse los trabajos de filósofs de diferentes tradiciones como Ortega y Gasset (1939), Heidegger (1954), Mumford (1971) Ellul (1960) y la Escuela de Frankfurt. Por otro lado, una filosofía de la técnica “ingenieril” que consiste en el análisis de la tecnología como un paradigma de pensamiento y acción humana. Esta dicotomía ha sido interpretada por Eco como “apocalípticos e integrados”. Más allá de las mencionadas diferencias, lo que tienen en común ambas posiciones es que parten de una dicotomía entre cultura y naturaleza. Nuestra perspectiva rechaza esta dicotomía, por el contrario, evidenciamos una creciente imbricación entre ambas donde las fronteras entre una y otra se hacen difusas. La noción de “objeto técnico” propuesta por Simondon (2007) hace referencia a la inserción del objeto técnico en la cultura, donde debe reconocerse la “realidad humana” presente en el mismo. Ahora bien, esto no significa “humanizar el objeto técnico”, sino más bien indagar sobre el lugar que este ocupa en la cultura como también establecer su relación con la naturaleza. En el siglo XVII el hombre mismo es reinterpretado como máquina (La Mettrie, 2000). En la actualidad pueden identificarse dos tendencias en la concepción de la técnica: los «humanos-máquinas» y las «máquinas-humanas», en otras palabras, la disposición del humano hacia la máquina y la tendencia de la máquina hacia lo humano. No obstante, ambas posiciones siguen manteniendo una distinción taxonómica entre el cuerpo –o lo orgánico- y lo maquínico, lo que implica una consideración de esta relación de manera extrínseca. Frente a esta tensión Haraway propone el concepto de cyborg: «un organismo cibernético» (1995). Los desarrollos tecnológicos han producido una modificación tal en la vida de los seres orgánicos en los cuales ya no puede concebirse su cuerpo independientemente de la tecnología. Esto conduce a replantear la distinción entre “animales/hombres/máquinas”, entendiendo a los mismos como expresiones de naturaleza, cultura y tecnología respectivamente. Nuestra investigación parte de la hipótesis que la técnica diluye diferencias de orden natural y cultural a través de los objetos técnicos que son productos culturales. La estética se ocupa de la percepción sensible del mundo no puede eludir su dimensión técnica. Al margen de la crítica a la “Industria cultural” consideramos relevante la aproximación de Benjamin al problema de la técnica porque aborda la imbricación antes mencionada en el campo de la percepción. Según Benjamin la irrupción de la técnica al mismo tiempo que posibilita una estetización de la política que confluye en el fascismo como punto extremo también abre la posibilidad de desmontar la ideología del progreso infinito (1967). Una integración entre aproximaciones estéticas y políticas a la técnica Flusser (1983) propone la “caja negra” como metáfora de la técnica contemporánea. Su propuesta es la “apertura de la caja negra” que consiste en tomar conocimiento del funcionamiento del dispositivo. Nuestra propuesta de investigación aborda la técnica desde una consideración filosófica/estética/política, donde redefiniremos la técnica partiendo de la imbricación entre cultura y naturaleza. This project will set the basis for a sustained research on the relation nature/culture/technique. They have been traditionally considered as separate and even opposite fields. And it is on the brink of this distinction where technique plays a central role. In Western thought technique has received many interpretations since the beginnings of philosophy: from a subordination to true knowledge (episteme) in classic philosophy, or the optimism which sees in technique the possibility of dominating nature in the Renaissance and in the Enlightenment, to the Romantic ambiguity and uneasiness towards technological change (Mitcham, 1979). During the twentieth century two opposed approach on technique prevail. On one hand, a “critical” attitude such defines the work of philosophers of different traditions such as Ortega y Gasset (1939), Heidegger (1954), Mumford (1971) Ellul (1960) and the Frankfurt School. On the other hand there is an “engineering” philosophy of technique that consists in the analisis of technology as a paradigm to understand human action and thought. Besides their differences, both positions have in common a dichotomy between nature and culture. We reject such dichotomy. On the contrary we consider there is a growing intertwinement between both which blurs the borders of the concepts. Simondon’s notion of “technical object” refers to the insertion of the technique in culture where the “human reality” in it must be recognised. This does not imply “humanising the technical object”, but investigate on the role it plays on culture and establishing its relation to nature. To articulate this relation we will work with unorthodox approaches on technique such as Benjamin (1967), Flusser (1983) and others. The hypothesis of our project is that the traditional distinction of “animal/man/machine” must be re-thought, therefore raising the question on the blurring line between nature, culture and technique and its effects in philosophy, politics and aesthetics.

Technique and clinical applications of double balloon enteroscopy for the evaluation of small bowel diseases

Magdeburg, Univ., Med. Fak., Diss., 2012

Identification technique of mechanism-based constitutive model for cast iron under thermo-mechanical loads

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2015

Bidding at sequential first-price auctions with(out) supply uncertainty: a laboratory analysis

We report on a series of experiments that test the effects of an uncertain supply on the formation of bids and prices in sequential first-price auctions with private-independent values and unit-demands. Supply is assumed uncertain when buyers do not know the exact number of units to be sold (i.e., the length of the sequence). Although we observe a non-monotone behavior when supply is certain and an important overbidding, the data qualitatively support our price trend predictions and the risk neutral Nash equilibrium model of bidding for the last stage of a sequence, whether supply is certain or not. Our study shows that behavior in these markets changes significantly with the presence of an uncertain supply, and that it can be explained by assuming that bidders formulate pessimistic beliefs about the occurrence of another stage.

Sequential formation of coalitions through bilateral agreements

We study a sequential protocol of endogenous coalition formation based on a process of bilateral agreements among the players. We apply the game to a Cournot environment with linear demand and constant average costs. We show that the final outcome of any Subgame Perfect Equilibrium of the game is the grand coalition, provided the initial number of firms is high enough and they are sufficiently patient.

Welfare comparisons: sequential procedures for heterogenous populations

Some analysts use sequential dominance criteria, and others use equivalence scales in combination with non-sequential dominance tests, to make welfare comparisons of oint distributions of income and needs. In this paper we present a new sequential procedure hich copes with situations in which sequential dominance fails. We also demonstrate that there commendations deriving from the sequential approach are valid for distributions of equivalent income whatever equivalence scale the analyst might adopt. Thus the paper marries together the sequential and equivalizing approaches, seen as alternatives in much previous literature. All results are specified in forms which allow for demographic differences in the populations being compared.

Evaluation de la douleur chez les personnes cérébrolésées non-communicantes aux soins intensifs

La douleur est fréquente en milieu de soins intensifs et sa gestion est l'une des missions des infirmières. Son évaluation est une prémisse indispensable à son soulagement. Cependant lorsque le patient est incapable de signaler sa douleur, les infirmières doivent se baser sur des signes externes pour l'évaluer. Les guides de bonne pratique recommandent chez les personnes non communicantes l'usage d'un instrument validé pour la population donnée et basé sur l'observation des comportements. A l'heure actuelle, les instruments d'évaluation de la douleur disponibles ne sont que partiellement adaptés aux personnes cérébrolésées dans la mesure où ces personnes présentent des comportements qui leur sont spécifiques. C'est pourquoi, cette étude vise à identifier, décrire et valider des indicateurs, et des descripteurs, de la douleur chez les personnes cérébrolésées. Un devis d'étude mixte multiphase avec une dominante quantitative a été choisi pour cette étude. Une première phase consistait à identifier des indicateurs et des descripteurs de la douleur chez les personnes cérébrolésées non communicantes aux soins intensifs en combinant trois sources de données : une revue intégrative des écrits, une démarche consultative utilisant la technique du groupe nominal auprès de 18 cliniciens expérimentés (6 médecins et 12 infirmières) et les résultats d'une étude pilote observationnelle réalisée auprès de 10 traumatisés crâniens. Les résultats ont permis d'identifier 6 indicateurs et 47 descripteurs comportementaux, vocaux et physiologiques susceptibles d'être inclus dans un instrument d'évaluation de la douleur destiné aux personnes cérébrolésées non- communicantes aux soins intensifs. Une deuxième phase séquentielle vérifiait les propriétés psychométriques des indicateurs et des descripteurs préalablement identifiés. La validation de contenu a été testée auprès de 10 experts cliniques et 4 experts scientifiques à l'aide d'un questionnaire structuré qui cherchait à évaluer la pertinence et la clarté/compréhensibilité de chaque descripteur. Cette démarche a permis de sélectionner 33 des 47 descripteurs et valider 6 indicateurs. Dans un deuxième temps, les propriétés psychométriques de ces indicateurs et descripteurs ont été étudiés au repos, lors de stimulation non nociceptive et lors d'une stimulation nociceptive (la latéralisation du patient) auprès de 116 personnes cérébrolésées aux soins intensifs hospitalisées dans deux centres hospitaliers universitaires. Les résultats montrent d'importantes variations dans les descripteurs observés lors de stimulation nociceptive probablement dues à l'hétérogénéité des patients au niveau de leur état de conscience. Dix descripteurs ont été éliminés, car leur fréquence lors de la stimulation nociceptive était inférieure à 5% ou leur fiabilité insuffisante. Les descripteurs physiologiques ont tous été supprimés en raison de leur faible variabilité et d'une fiabilité inter juge problématique. Les résultats montrent que la validité concomitante, c'est-à-dire la corrélation entre l'auto- évaluation du patient et les mesures réalisées avec les descripteurs, est satisfaisante lors de stimulation nociceptive {rs=0,527, p=0,003, n=30). Par contre la validité convergente, qui vérifiait l'association entre l'évaluation de la douleur par l'infirmière en charge du patient et les mesures réalisés avec les descripteurs, ainsi que la validité divergente, qui vérifiait si les indicateurs discriminent entre la stimulation nociceptive et le repos, mettent en évidence des résultats variables en fonction de l'état de conscience des patients. Ces résultats soulignent la nécessité d'étudier les descripteurs de la douleur chez des patients cérébrolésés en fonction du niveau de conscience et de considérer l'hétérogénéité de cette population dans la conception d'un instrument d'évaluation de la douleur pour les personnes cérébrolésées non communicantes aux soins intensifs. - Pain is frequent in the intensive care unit (ICU) and its management is a major issue for nurses. The assessment of pain is a prerequisite for appropriate pain management. However, pain assessment is difficult when patients are unable to communicate about their experience and nurses have to base their evaluation on external signs. Clinical practice guidelines highlight the need to use behavioral scales that have been validated for nonverbal patients. Current behavioral pain tools for ICU patients unable to communicate may not be appropriate for nonverbal brain-injured ICU patients, as they demonstrate specific responses to pain. This study aimed to identify, describe and validate pain indicators and descriptors in brain-injured ICU patients. A mixed multiphase method design with a quantitative dominant was chosen for this study. The first phase aimed to identify indicators and descriptors of pain for nonverbal brain- injured ICU patients using data from three sources: an integrative literature review, a consultation using the nominal group technique with 18 experienced clinicians (12 nurses and 6 physicians) and the results of an observational pilot study with 10 traumatic brain injured patients. The results of this first phase identified 6 indicators and 47 behavioral, vocal and physiological descriptors of pain that could be included in a pain assessment tool for this population. The sequential phase two tested the psychometric properties of the list of previously identified indicators and descriptors. Content validity was tested with 10 clinical and 4 scientific experts for pertinence and comprehensibility using a structured questionnaire. This process resulted in 33 descriptors to be selected out of 47 previously identified, and six validated indicators. Then, the psychometric properties of the descriptors and indicators were tested at rest, during non nociceptive stimulation and nociceptive stimulation (turning) in a sample of 116 brain-injured ICLI patients who were hospitalized in two university centers. Results showed important variations in the descriptors observed during the nociceptive stimulation, probably due to the heterogeneity of patients' level of consciousness. Ten descriptors were excluded, as they were observed less than 5% of the time or their reliability was insufficient. All physiologic descriptors were deleted as they showed little variability and inter observer reliability was lacking. Concomitant validity, testing the association between patients' self report of pain and measures performed using the descriptors, was acceptable during nociceptive stimulation (rs=0,527, p=0,003, n=30). However, convergent validity ( testing for an association between the nurses' pain assessment and measures done with descriptors) and divergent validity (testing for the ability of the indicators to discriminate between rest and a nociceptive stimulation) varied according to the level of consciousness These results highlight the need to study pain descriptors in brain-injured patients with different level of consciousness and to take into account the heterogeneity of this population forthe conception of a pain assessment tool for nonverbal brain-injured ICU patients.

Studies on survival, biological activities and behavior of Biomphalaria glabrata, the host snail of Schistosomiasis, submitted to increased hydrostatic pressure: a technique

To study changes in survival, in biological activities and behavior of planorbids submitted to increased hydrostatic pressure, we developed a technique using two transparent chambers and a hydraulic piston. The apparatus permitted renewal of the liquid medium without substantial variations in pressure, thus eliminating excretion products and maintaining the desired O2 level and thereby permitting us to evaluate the effects of pressure independently of the occurrence of anoxia. Pressure was maintained without any contact of the liquid medium with compressed air, a situation which reproduced with relative fidelity what occurs in nature and assured the presence of the same amounts of gases in the two observation chambers (Control and Experimental). Biomphalaria glabrata was found to be able to survive at least 48 hours when submitted to 49.02 x 10**4 Pa (equivalent to a water depth of 48.8 m), continuing to day egg masses and showing few behavioral changes when compared with the control group.

Hydrogeophysical data integration at larger scales: Application of Bayesian sequential simulation for the characterization of heterogeneous alluvial aquifers

Knowledge of the spatial distribution of hydraulic conductivity (K) within an aquifer is critical for reliable predictions of solute transport and the development of effective groundwater management and/or remediation strategies. While core analyses and hydraulic logging can provide highly detailed information, such information is inherently localized around boreholes that tend to be sparsely distributed throughout the aquifer volume. Conversely, larger-scale hydraulic experiments like pumping and tracer tests provide relatively low-resolution estimates of K in the investigated subsurface region. As a result, traditional hydrogeological measurement techniques contain a gap in terms of spatial resolution and coverage, and they are often alone inadequate for characterizing heterogeneous aquifers. Geophysical methods have the potential to bridge this gap. The recent increased interest in the application of geophysical methods to hydrogeological problems is clearly evidenced by the formation and rapid growth of the domain of hydrogeophysics over the past decade (e.g., Rubin and Hubbard, 2005).