Near-field polarization conversion in planar chiral nanostructures

Enantiomeric-sensitive optical polarization conversion has been observed in the near-field above a planar chiral nanostructures consisting of an array of gammadions cut in a metal film. Formation of the far-field scattered light rotated with respect to the incident linear polarized light has been visualized

Nematicidal activity of Bacillus thuringiensis isolates

L'activité nématicide de mélanges de spores et d'inclusions cristallines de trois isolats de #Bacillus thuringiensis envers les juvéniles et les adultes de #Caenorhabditis elegans est étudiée. La toxicité est déterminée en ajoutant 50 micro l d'une suspension de 200 à 400 juvéniles et adultes de "C. elegans$. La mortalité des nématodes est observée après 8 heures d'incubation ; aucune augmentation significative du pourcentage de mortalité n'est observée après 24 heures d'incubation. Ce pourcentage varie d'environ 50 à 60 % lorsque les tests sont réalisés avec de l'eau distillée et il augmente légèrement (moins de 10 %) si les tests sont effectués en milieu axénique. La toxicité varie selon les isolats. Un minimum de 10 8 particules/ml est nécessaire pour provoquer un effet létal supérieur à 3%. L'activité nématicide n'est observée qu'avec des mélanges de spores et d'inclusions critallines provenant de cultures âgées d'au moins 2 jours et constituées d'environ 50 % de cellules végétatives - contenant souvent une spore - et d'environ 50 % d'une mixture de spores et d'inclusions critallines. Le chauffage à 75 °C ou plus pendant 24 heures ou un autoclavage à 120°C pendant 20 minutes détruit l'activité nématicide des trois isolats. Des différences de stabilité de l'activité nématicide sont observées entre les trois isolats. Celle-ci ne diminue pas pour deux isolats maintenus à 28°C durant quinze jours, mais elle diminue pour le troisième s'il est stocké sept jours à 28°C. De même, l'activité nématicide de deux des isolats n'est pas modifiée après plusieurs congélations à -20°C ou -70°C suivies de décongélations, mais elle diminue pour le troisième isolat. Les variations du pH des mélanges de particules entraînent des variations dans la stabilité des activités nématicides des trois isolats. Ces résultats pourraient indiquer la présence de toxines différentes. (Résumé d'auteur

The effect of structural changes on magnetic permeability of amorphous powder Ni80Co20

The structural changes of Ni80Co20 amorphous powder were tested during heating. The alloy was obtained by electrolysis from ammonia solution sulfate of cobalt and nickel on the titanium cathode. The differential scanning calorimetry (DSC) method was used to detect that the crystallization process of powder occurred in two stages with crystallization peaks temperatures of the first stage at 690 K and of the second stage at 790 K. The effect of structural relaxation and crystallization of powder on magnetic properties was predicted by measurement of the relative magnetic permeability change in isothermal and nonisothermal conditions. On the basis of the time change of relative magnetic permeability at a defined temperature in the temperature range of the first and second crystallization peak on the thermogram, the kinetics of crystallization was defined. It was predicted, that in the initial time interval, in the range of the first crystallization peak, the rate of crystallization is determined by the rate of nucleation of the amorphous part of the powder. However, in the second time interval, the crystallization rate is determined by the rate of diffusion. In the range of the second peak, in the beginning the rate of crystal growth is determined by activation energy of the atom pass from smaller to bigger crystal grain. In second time interval, the rate of crystal grain growth is determined by the diffusion rate of atoms to the location of integration into bigger crystal grains. For all processes which determine the rate of crystallization in temperature ranges of both crystallization peaks, the Arrhenius temperature dependence of rate for those processes is obtained. The relative magnetic permeability of crystallized powder at 873 K, is smaller for about 30 % than the relative magnetic permeability of fresh powder at room temperature. However, structurally relaxed powder at 573 K has an about 22 % larger magnetic permeability than the same fresh powder at room temperature

Effect of nematicidal Bacillus thuringiensis strains on free-living nematodes : 2. Ultrastructural analysis of the intoxication process in Caenorhabditis elegans

La microscopie électronique par transmission a été utilisée pour décrire l'intoxication de #Caenorhabditis elegans se nourrissant sur des spores/cristaux de #Bacillus thuringiensis. La toxine agit directement sur l'intestin où elle affecte initialement l'anneau de quatre cellules le plus antérieur. En 12 heures, le volume de ces cellules diminue considérablement, les microvillosités régressent lentement, de nombreux organites cellulaires subissent des changements spectaculaires pour être finalement détruits. Il n'a pas été observé de rupture de la membrane cellulaire apicale. Les tissus autres qu'intestinaux n'apparaissent pas affectés. Cette étude révèle des différences ultrastructurales considérables entre le mode d'action des toxines nématicides et celui des cristaux insecticides émanant les uns et les autres de #Bacillus thuringiensis$. (Résumé d'auteur

Effect of a nematicidal Bacillus thuringiensis strain on free- living nematodes : 3. Characterization of the intoxication process

La toxicité de #Bacillus thuringiensis est fonction de la température. L'incubation de #Caenorhabditis elegans avec des souches de #B. thuringiensis à 16, 20 et 25°C montre que la toxicité décroît en même temps que la température. A 16°C, la toxicité disparaît complètement, tandis qu'elle atteint son maximum à 25°C. La toxicité, fonction du pH, diminue significativement lorsque les nématodes sont mis en incubation dans des bases faibles (NH4Cl, chloroquine, acridine orange, rouge de méthyle, rouge neutre). A partir de ces résultats, il est possible d'avancer l'hypothèse que l'agent nématicide pénètre à l'intérieur des cellules intestinales, ce qui constitue une différence notable avec les toxines des souches insecticides de #B. thuringiensis lesquelles agissent au niveau de la membrane en brosse. Bien que l'absence de toxine purifiée ne permette pas l'élucidation définitive de son mode d'action, les résultats exposés dans cette troisième, et dernière, partie de la série de publications traitant du sujet, apportent une indication convaincante du fait que les souches nématicides de #B. thuringiensis$ ne peuvent tenir les mêmes promesses que les souches insecticides en tant qu'agent de contrôle biologique. (Résumé d'auteur

Effect of nematicidal Bacillus thuringiensis strains on free- living nematodes : 1. Light microscopic observations, species and biological stage specificity and identification of resistant mutants of Caenorhabditis elegans

L'observation en microscopie optique de l'action toxique des spores/cristaux de #Bacillus thuringiensis montre que, chez #Caenorhabditis elegans, l'intestin est détruit en deux phases sur une période de 24 h. L'anneau antérieur de quatre cellules constitue la première cible. Les observations indiquent que les tissus intestinaux sont les seuls détruits. Le criblage de quatorze autres espèces de Rhabditides vis-à-vis de trois souches nématicides de #B. thuringiensis actives contre #C. elegans a démontré qu'une seule de ces espèces était sensible et indiqué une forte spécificité du facteur nématicide. Cependant, au contraire des toxines de #B. thuringiensis douées de spécificité envers les insectes, les toxines nématicides ne montrent qu'une faible spécificité envers les différents stades de #C. elegans, tous les stades, y compris les adultes, étant sensibles. De plus, la sensibilité s'accroît lors du processus de développement. Deux mutants de #C. elegans$, obtenus par action de l'éthyle-méthyle-sulfonate, montrent une sensibilité réduite de 50$ envers laquelle elle n'avait pas été testée. Des données préliminaires indiquent que cette réduction de la sensibilité chez les mutants n'est pas causée par une diminution de l'activité de pompage du pharynx. (Résumé d'auteur

Exploring excited states of Pt(ii) diimine catecholates for photoinduced charge separation

The intense absorption in the red part of the visible range, and the presence of a lowest charge-transfer excited state, render Platinum(II) diimine catecholates potentially promising candidates for light-driven applications. Here, we test their potential as sensitisers in dye-sensitised solar cells and apply, for the first time, the sensitive method of photoacoustic calorimetry (PAC) to determine the efficiency of electron injection in the semiconductor from a photoexcited Pt(II) complex. Pt(II) catecholates containing 2,2′-bipyridine-4,4′-di-carboxylic acid (dcbpy) have been prepared from their parent iso-propyl ester derivatives, complexes of 2,2′-bipyridine-4,4′-di-C(O)OiPr, (COOiPr)2bpy, and their photophysical and electrochemical properties studied. Modifying diimine Pt(II) catecholates with carboxylic acid functionality has allowed for the anchoring of these complexes to thin film TiO2, where steric bulk of the complexes (3,5-ditBu-catechol vs. catechol) has been found to significantly influence the extent of monolayer surface coverage. Dye-sensitised solar cells using Pt(dcbpy)(tBu2Cat), 1a, and Pt(dcbpy)(pCat), 2a, as sensitisers, have been assembled, and photovoltaic measurements performed. The observed low, 0.02–0.07%, device efficiency of such DSSCs is attributed at least in part to the short excited state lifetime of the sensitisers, inherent to this class of complexes. The lifetime of the charge-transfer ML/LLCT excited state in Pt((COOiPr)2bpy)(3,5-di-tBu-catechol) was determined as 250 ps by picosecond time-resolved infrared spectroscopy, TRIR. The measured increase in device efficiency for 2a over 1a is consistent with a similar increase in the quantum yield of charge separation (where the complex acts as a donor and the semiconductor as an acceptor) determined by PAC, and is also proportional to the increased surface loading achieved with 2a. It is concluded that the relative efficiency of devices sensitised with these particular Pt(II) species is governed by the degree of surface coverage. Overall, this work demonstrates the use of Pt(diimine)(catecholate) complexes as potential photosensitizers in solar cells, and the first application of photoacoustic calorimetry to Pt(II) complexes in general

Rastreamento de Jogadores de Futebol em Seqüência de Imagens

Este trabalho propõe um sistema de rastreamento visual de jogadores de futebol, o qual estima as trajetórias 2D em seqüências de imagens capturadas por câmeras fixas, instaladas ao redor de um campo de futebol. O rastreamento permite determinar diversos parâmetros como, por exemplo, a velocidade e a distância percorrida pelos jogadores durante uma partida, a região de maior movimentação da equipe no campo, etc. O sistema proposto segue uma abordagem probabilística, alcançando bons resultados iniciais. Os experimentos mostraram que uma implementação inicial do sistema, utilizando somente informação de variação da intensidade luminosa das imagens, já apresenta resultados eficazes e eficientes e permite vislumbrar melhorias significativas a serem desenvolvidas

Ventilation and oxygenation of major trauma patients in ICU

Centrul Național Stiințifico-Practic de Medicină de Urgență, Catedra Anesteziologie Reanimatologie Nr. 1, USMF „N. Testemițanu”, Conferinţa a XI-a Naţională a ortopezilor-tramatologi din Republica Moldova “Politraumatisme – concepţii contemporane de diagnostic şi tratament”, 21 mai 2009, Chișinău, Republica MoldovaAstăzi traumatismul este comparat cu o epidemie. Unul din obiectivele de bază a managementului traumatismului major este oxigenarea și ventilația pulmonară. În articolul nostru am studiat câteva aspecte de VAP (ventilația artificială pulmonară) în traumatismele majore – indicațiile și regimurile VAP, ca unul din componenții complexului de tratament în traumatismul major cât și câteva aspecte ale strategiei ventilației pulmonare protective (protective lung ventilation).Currently trauma is recognized as an epidemic. One of priority directions in major trauma management is oxygenation and ventilation. In our article we have studied some aspects of mechanical ventilation in major trauma: indications and modes, as one important component in the management of major trauma, some aspects of use of protective lung ventilation

Interhospital transportation of major trauma patients in the Republic of Moldova

NCEM (Centre of Emergency Medicine), SMPhU (State Medical and Pharmaceutical University) „N. Testemitanu”, Congresul II Internaţional al Societăţii Anesteziologie Reanimatologie din Republica Moldova 27-30 august 2009Actuality Transportation of major trauma patients to, between, and within hospitals can be associated with potentially adverse events. Researchers have shown that increased vigilance, appropriate equipment, and well-trained personnel can lead to improved safety while major trauma patients are being transported. The aim of the study is to evaluate interhospital transportation of major trauma patients from district hospitals to trauma center on territory the Republic of Moldova. Materials and Methods Was performed retrospective analysis of 39 patients from archive, transferred from regional hospitals to National Centre of Emergency Medicine (NCEM) during the year 2008. Age between 20-74 years, 30 males, 9 females. Severity of trauma was evaluated according to NISS (New Injury Severity Score) with average value 45,1 ± 10,3 points, and MPMoIII (Mortality Probability Admission Model), with average value 67,3±18,9%. Patients were analyzed in dependencies on period of trauma, on distance and on severity of trauma. Results In table №1 is represented two comparable groups according to number of patients, gender, age, NISS. Patients who were transported before 48 hours were influenced by transportation more vastly (MPMoIII is higher) and had mortality in two times above. Rate of mortality was less for patients who were transported from distance < 70 km (table №2). Rate of mortality was directly dependant on severity of trauma (NISS) and conditions at admission (MPMoIII) in trauma center (table №3) and increased vastly in cause NISS>40 or MPMoIII>70%. Conclusions 1. It was observed some tendencies for major trauma patients during transportation. They depend on phase of trauma, distance between hospitals and severity of trauma according to NISS and MPMoIII. 2. The transportation of major trauma patients needs optimization through increasing caution, good equipping and special trained personal. 3. Activity of Department of Emergency Medicine should be directed on achievement of “Golden Hour” strategy in all territory the Republic of Moldova