Imaging Characterization of Current Generating Lipid-protein Membranes

Imaging Characterization of Current Generating Lipid-protein Membrane

Characterization of Bacteriorhodopsin and Halorhodopsin Reconstituted in Lipid Bilayer Membranes

Motivated to produce electricity with photon activated ion pumps, the main purpose of this work was to characterize the photosynthetic membrane proteins bacteriorhodopsin (proton pump) and halorhodopsin (chloride pump). The proteins were re-suspended in lipid bilayers. For this work, an experimental set-up was built which included: chambers for lipid bilayer formation and characterization, lasers for ion pump activation, and an AxoPatch electrophysiology system for small photocurrent measurement. Lipid bilayer membranes were formed using mostly folding method: folding two monolayers together. The membranes were characterized by their resistance, capacitance, and generated photocurrent. Photocurrent was generated upon illumination of lipid-protein membranes with lasers. A green (532 nm) laser was used to illuminate bacteriorhodopsin containing membranes to produce proton-based positive photocurrent, while a purple (405 nm) laser was used to illuminate halorhodopsin containing membranes to generate chloride-based negative photocurrent. The investigation included: the generation of photocurrent using formed lipid-protein membranes and their voltage dependence, the study of the effect of laser intensity and protein concentration on the photocurrent amplitude and efficiency, the TEM-imaging of photocurrent generating lipid-protein solutions, and an equation that can help predict photocurrent amplitude in the defined protein concentration range

Processus d’intégration des migrants Mbororo à l’économie urbaine : cas de Bafoussam et Dschang (Ouest-Cameroun)

Présents sur la quasi-totalité du territoire camerounais, les Mbororo sont un peuple d’éleveurs semi-nomades qui résident principalement en zone rurale. Cependant, leur espace vital traditionnel étant de plus en plus saturé (multiplication des hommes et par là réduction de l’espace pastoral) et en proie à des conflits, ils sont nombreux qui migrent pour la ville où ils se sédentarisent. L’objectif de cette étude est de présenter le processus d’intégration des migrants Mbororo à l’économie urbaine à Bafoussam et à Dschang. Des enquêtes ont été menées auprès de 270 Mbororo dans la ville de Bafoussam et 230 dans la ville de Dschang. Elles ont été conduites à l’aide de questionnaires individuels. Les résultats montrent que nombreux sont les Mbororo qui se lancent dans le secteur informel, principalement dans le commerce, ceci à cause de la sous-scolarisation, du frein de la langue, de l’absence de qualification professionnelle et de financement. Ilse met en place afin de faciliter cette intégration des processus de sédentarisation qui passent par l’auto-emploi, l’entraide familiale et les candidatures spontanées. Pour simplifier le processus de sédentarisation dans les activités urbaines de ce peuple rural, il s’avère impératif davantage vulgariser les formations académique et professionnelle (en campagne et en ville) et enfin, faciliter et simplifier les emprunts bancaires par toutes les couches sociales, pour permettre plus d’auto-emplois et par là la création d’emplois. Present on almost all the Cameroonian territory, Mbororos are a people of semi-nomadic breeders who live mainly in rural areas. However, their traditional living space being more and more saturated (multiplication of men and thereby reduction of pastoral space) and in the grip of conflicts, many of them migrate to the city where they settle down. The objective of this study is to present the integrating process of Mbororo migrants into the urban economy in Bafoussam and Dschang. Surveys were conducted with 270 Mbororos in the city of Bafoussam and 230 in the city of Dschang. They were conducted using individual questionnaires. The results show that many Mbororos enter into the informal sector, mainly into trade, because of under-education, language barrier, lack of professional qualification and funding. Sedentarisation processes which include self-employment, family support and spontaneous applications are being put in place to facilitate this integration. To simplify the sedentarisation process in the urban activities of this rural people, it is imperative to put more emphasis on the importance of schooling, to encourage various professional training and finally to grant and simplify access to funding, to allow more self-employment and thereby job creation

An Online Data-Driven Method to Locate Forced Oscillation Sources from Power Plants Based on Sparse Identification of Nonlinear Dynamics (SINDy)

Forced oscillations may jeopardize the secure operation of power systems. To mitigate forced oscillations, locating the sources is critical. In this paper, leveraging on Sparse Identification of Nonlinear Dynamics (SINDy), an online purely data-driven method to locate the forced oscillation is developed. Validations in all simulated cases (in the WECC 179-bus system) and actual oscillation events (in ISO New England system) in the IEEE Task Force test cases library are carried out, which demonstrate that the proposed algorithm, requiring no model information, can accurately locate sources in most cases, even under resonance condition and when the natural modes are poorly damped. The little tuning requirement and low computational cost make the proposed method viable for online application.Comment: ACCEPTED BY IEEE TRANSACTIONS ON POWER SYSTEMS FOR FUTURE PUBLICATIO

Fluctuations supracondictrices dans les conducteurs organiques quasi-1D

L'origine des déviations observées aux basses températures sur la conductivité des matériaux organiques quasi-1D reste à ce jour contreversée. Il est établi pour ces matériaux que les fluctuations magnétiques y sont présentes. L'objectif visé par notre travail est d'évaluer l'influence des fluctuations supraconductrices induites par l'antiferromagnétisme dans les conducteurs quasi-1D. Il ressort de nos calculs que la paraconductivité à un canal (Cooper), calculée à partir du courant de paires coïncide à celle d'Aslamazov-Larkin. Pour une dimension spatiale donnée, plus l'anisotropie est prononcée plus les fluctuations deviennent importantes. Dans le cas quasi-1D avec mélange des canaux de Cooper et de Peierls, on retrouve le résultat d'Aslamazov-Larkin à une constante près. Nos résultats s'accordent qualitativement aux données expérimentales avec un paramètre d'anisotropie fortement influencé par la pression. De même, on remarque que la pression lorsqu'elle augmente diminue les fluctuations supraconductrices. En outre l'interférence des canaux augmente la conductivité des conducteurs organiques quasi-1D de manière significative

Stratégie d'échantillonnage des mesures LIBS in situ de la teneur en or dans des échantillons miniers : optimisation par analyse statistique

Au Québec, 19 mines d'or produisent plus de 1.8 milliard dollars canadiens d'or annuellement. Dans ces mines, des centaines d'échantillons de roches sont collectées quotidiennement, et envoyées au laboratoire afin de déterminer leurs concentrations en or. Étant donné que les résultats du laboratoire ne sont disponibles qu'après 24 à 48 heures, il s'en suit un impact direct négatif sur les activités minières. Les avancées technologiques des dernières années laissent croire que la spectroscopie sur plasma induite par laser (LIBS) pourrait constituer une technologie prometteuse pour mesurer en temps réel et in-situ, la teneur en or de la roche. Considérant la taille de chaque tir produit par le laser sur un échantillon de roche, à savoir 500 µm, de très nombreux tirs seront requis afin d'obtenir un résultat représentatif de l'échantillon analysé. À titre d'exemple, pour un échantillon de carotte de 50 cm de long, et une surface analysée comprise entre 70 et 80%, 10000 tirs lasers ont été effectués afin de s'assurer d'obtenir un résultat représentatif de l'échantillon, avec un temps d'acquisition d'une demi-journée en laboratoire, soit une durée trop longue pour une application pratique dans les mines. Pour cette raison, l'objectif de ce projet est de développer une stratégie afin de minimiser le nombre de tirs LIBS requis sur un échantillon à analyser, tout en demeurant représentatif de ce dernier, et ainsi obtenir une mesure fiable et précise de la teneur en or. Pour ce faire, une analyse statistique descriptive combinée à plusieurs motifs élaborés à partir des 10000 points de mesure est appliquée sur les données LIBS. En se fixant un compromis entre le nombre de tirs à réaliser sur un échantillon (roche) et le temps d'analyse, le motif défini « Boucle » minimise le mieux le nombre de tirs avec un temps d'analyse acceptable par une opération minière. À partir de ce dernier, un protocole d'échantillonnage a été élaboré, où pour être représentatif des échantillons de carottes, 1500 tirs sont nécessaires tandis que pour les échantillons de roches, seuls 100 tirs suffisent. Cependant, il serait important de pouvoir tester ce protocole d'échantillonnage sur plusieurs échantillons miniers afin de pouvoir valider ce dernier.In Quebec, 19 gold mines produce more than C (dollar) 1.8 billion of gold annually. In these mines, hundreds of rock samples are collected daily and sent to the laboratory to determine their gold concentrations. Since laboratory results are only available after 24 to 48 hours, there is a direct negative impact on mining activities. Technological advances in recent years suggest that Laser Induced Breakdown Spectroscopy (LIBS) may be a promising technology for real-time and in-situ measurement of the gold content of rock samples. Considering the size of each shot produced by the laser on a rock sample, namely 500 µm, many shots will be required in order to obtain a representative result of the sample analyzed. For example, for a 50 cm long core sample, and a surface analyzed between 70 and 80%, 10,000 laser shots were fired to ensure to obtain a result representative of the sample, with an acquisition time of half a day in the laboratory, which is a too long period of time for a practical application in mines. For this reason, the objective of this project is to minimize the number of LIBS shots required on a sample to be analyzed, while remaining representative of the latter, and thus obtain a reliable and accurate measurement of the gold content. For this, a descriptive statistical analysis combined with several elaborate patterns is applied to the 10,000 LIBS data obtained. By setting a compromise between the number of shots to be made on a sample and the analysis time, the Loop pattern minimizes the number of shots with an acceptable analysis time. From the latter, a sampling protocol has been developed, where to be representative of core samples, 1500 shots are needed whereas for rock samples, only 100 shots are needed. However, it would be important to b

Utiliação de diferentes subprodutos de origem animal na alimentação de frangos de corte

Resumo: Este trabalho foi desenvolvido com o objetivo de avaliar o desempenho zootécnico e a viabilidade econômica de frangos de corte, utilizando quatro tratamentos diferentes em relação às fontes de proteína. O tratamento Ti tinha farelo de soja como fonte de proteína, enquanto o T2 tinha além do farelo de soja em todas as fases, a farinha de vísceras na fase inicial, e a de penas e vísceras nas fases de crescimento e final. Os suplementos protéicos de T3, em todas as fases, foram o farelo de soja e a farinha de carne e ossos. Por sua vez, o T4 constou de farelo de soja, farinha de carne e ossos, e farinha de penas e vísceras, como fontes de proteína, nas três fases. Foram utilizados 2.800 pintinhos de corte, da linhagem Ross, machos e fêmeas (proporções aproximadamente iguais), com um dia de idade e peso médio de 37,67 g, alojados em 28 boxes. A fim de se garantir a isonomia das condições ambientais, as aves alojadas nos 4 boxes dos cantos não fizeram parte do experimento propriamente dito. O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos e 6 repetições, sendo 100 aves por unidade experimental. Durante os 46 dias de experimento, as aves tinham livre acesso à ração e à água. Os dados eram coletados diariamente, e/ou semanalmente, para posterior cálculo dos índices zootécnicos e do custo de produção. Os índices zootécnicos foram avaliados através da análise de variância e classificação de médias (teste de TUKEY). Para a variável peso médio aos 21 dias, o tratamento farelo de soja mais farinha de carne e ossos (T3) promoveu o melhor resultado, seguido pelo tratamento que tinha a combinação de farelo de soja, farinha de carne e ossos e farinha de penas e vísceras como fontes protéicas (T4), o tratamento T2 (farelo de soja mais farinha de vísceras) tendo apresentado o 32 melhor resultado, e finalmente aquele com farelo de soja como única fonte (T(). Aos 46 dias, as aves de Ti tiveram o maior peso médio, seguidas pelas do T4, aquelas do T3 e finalmente os animais do T2. Houve diferença estatisticamente significativa (p T4 > T3 > T2, sem diferença estatística. No consumo de ração, não houve diferença estatística entre os tratamentos, em qualquer das duas fases. Em termos de custo de produção/kg de frango, calculado aos 46 dias, a ordem do mais barato para o mais oneroso foi T4, T2, Tt e T3, com T3 - T4 = R$ 0,045/kg de frango produzido. Aos 21 dias de idade, o tratamento T4 foi o de menor custo e Ti o mais caro

Exploring fraity and sarcopenia in older adults admitted to acute medical unit, looking at prevalence, trajectory, and outcomes:A protocol testing the feasibility and acceptability of the TYSON study

BackgroundFrailty and sarcopenia are common in older people and are associated with adverse outcomes including increased mortality and morbidity. It is unclear whether screening for frailty and sarcopenia would identify specific populations most at risk of poor outcomes during unplanned hospital admissions, which screening tools should be used and what the trajectory of both conditions are over the course of an admission. The TYSON study is an observational cohort study aiming to determine the prevalence, trajectory and outcomes associated with frailty and sarcopenia in different patient cohorts. This protocol tests the feasibility and acceptability of TYSON processes.ObjectivesTo determine in acutely admitted medical patients who are older adults: Primary: The feasibility and acceptability of frailty and sarcopenia assessments; Secondary: (1) Differences in community and hospital frailty assessments, as assessed by the medical team, the patient and elderly care physicians, (2) The dynamic changes in frailty and sarcopenia during a hospital admission, and patient outcomes; Exploratory: Inflammatory and metabolic mediators associated with frailty and sarcopenia.MethodsA single centre, prospective observational study including patients aged ≥ 65 years admitted to an acute medical unit. Frailty assessments include the Rockwood clinical frailty and e-frailty index. Sarcopenia assessments include the Bilateral Anterior Thigh Thickness (BATT) measurement. Each participant will be asked to complete 5 visits, at day 0, day 3, day 7, month 3 and month 6. Blood samples will be collected to explore inflammatory and metabolic markers associated with frailty and sarcopenia. The study and protocol have been ethically approved by the Health Research Authority (REC 20/WA/0263).DiscussionThe study will determine the feasibility and acceptability of frailty and sarcopenia assessments in an acute hospital setting, and inform on the prevalence, trajectory and associated outcomes of frailty and sarcopenia in this group of patients. An inflammatory and metabolic profile will be explored in frailty and sarcopenia