928 resultados para SPECTROSCOPIC INVESTIGATIONS
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Tiivistelmä: Leijailmakuvausmenetelmän käyttömahdollisuudet soiden kartoituksessa - esimerkkejä Viron soilta
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An understanding of details of the interaction mechanisms of bacterial endotoxins (lipopolysaccharide, LPS) with the oxygen transport protein hemoglobin is still lacking, despite its high biological relevance. Here, a biophysical investigation into the endotoxin:hemoglobin interaction is presented which comprises the use of various rough mutant LPS as well as free lipid A; in addition to the complete hemoglobin molecule from fetal sheep extract, also the partial structure alpha-chain and the heme-free sample are studied. The investigations comprise the determination of the gel-to-liquid crystalline phase behaviour of the acyl chains of LPS, the ultrastructure (type of aggregate structure and morphology) of the endotoxins, and the incorporation of the hemoglobins into artificial immune cell membranes and into LPS. Our data suggest a model for the interaction between Hb and LPS in which hemoglobins do not react strongly with the hydrophilic or with the hydrophobic moiety of LPS, but with the complete endotoxin aggregate. Hb is able to incorporate into LPS with the longitudinal direction parallel to the lipid A double-layer. Although this does not lead to a strong disturbance of the LPS acyl chain packing, the change of the curvature leads to a slightly conical molecular shape with a change of the three-dimensional arrangement from unilamellar into cubic LPS aggregates. Our previous results show that cubic LPS structures exhibit strong endotoxic activity. The property of Hb on the physical state of LPS described here may explain the observation of an increase in LPS-mediating endotoxicity due to the action of Hb.
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In March of 2012, the Iowa Secretary of State’s office compared Iowa’s voter registration records with the driver’s license record s of individuals that identified themselves as non-citizens with the Iowa Department of Transportation. After comparing those records, the Iowa Secretary of State’s office found that more than 3,000 individuals registered to vote that had previously identified themselves as non-citizens. More than 1,000 of these individuals had also cast a ballot. The Iowa Secretary of State’s office was not given timely access to the federal Systematic Alien Verification for Entitlements (SAVE)database, and therefore was unable to determine if any of these individuals had become citizens before they registered to vote or cast a ballot. On June 21, 2012, the Iowa Secretary of State’s office entered into an agreement with the Iowa Department of Public Safety’s Division of Criminal Investigation (DCI) to review potential election misconduct crimes and improve the administration of federal elections. Over the last two years,DCI agents have reviewed thousands of instances of possible election misconduct. DCI’s review included cases referred by the Iowa Secretary of State’s office as well as by other state and local government agencies.
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Les manifestations ORL du reflux gastro-sophagien sont fréquentes. La pH-impédancemétrie permet dévaluer des reflux acides ou non acides et de déterminer leur extension proximale. A la lumière de deux patients de notre collectif, nous observons une corrélation entre reflux non acide et symptômes ORL dans le premier cas et une suppression acide insuffisante dans le deuxième cas. Ces résultats nous orientent vers un traitement spécifique complémentaire aux inhibiteurs de la pompe à protons. La pH-impédancemétrie détecte les reflux aussi bien acides que non acides, et analyse la concordance entre les symptômes et les épisodes de reflux. Elle permet ainsi une meilleure compréhension des manifestations ORL du reflux gastro-sophagien et une prise en charge thérapeutique mieux adaptée. ENT symptoms of gastro-esophageal reflux are frequent. pH-impedance can detect acid and non-acid reflux and measure their proximal extension. The technique identifies the refluxate by changes in impedance. We discuss 2 clinical situations where correlation of symptoms could be explained by a non-acid reflux in the first case, and a lack of acid suppression in the second case, respectively. These results lead to a specific additional treatment to proton pump inhibitors (PPI). This technology provides a better understanding of the pathogenesis of reflux laryngitis, and affords the prescription of PPI on a proven diagnosis. Detection of non-acid reflux leads to an optimized medical treatment.
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Two investigations are included in this document: 1) An Evaluation of Largemouth Bass Populations in the Upper Mississippi River and 2) An Evaluation of the Effects of a Change in Commercial Harvest Regulations on the Channel Catfish Population Inhabiting the Upper Mississippi River
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A reference for all health care providers at the time of a suspected case, a particular disease or condition, or at the time of an outbreak of a communicable disease to institute public health prevention and control measures.
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Abstract
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With the aim of understanding the mechanisms that control the metamorphic transition from the CH4- to the H2O-(CO2)-dominated fluid zone in the Helvetic domain of the Central Alps of Switzerland, fluid inclusions in quartz, illite ``crystallinity'' index, vitrinite reflectance, and the stable isotope compositions of vein and whole rock minerals and fluids trapped in quartz were investigated along four cross-sections. Increasing temperature during prograde metamorphism led to the formation of dry gas by hydrocarbon cracking in the CH4-zone. Fluid immiscibility in the H2O-CH4-(CO2)-NaCl system resulted in cogenetic, CH4- and H2O-dominated fluid inclusions. In the CH4-zone, fluids were trapped at temperatures <= 270 +/- 5 degrees C. The end of the CH4-zone is markedby a sudden increase of CO2 content in the gas phase of fluid inclusions. At temperatures > 270 +/- 5 degrees C, in the H2O-zone, the total amount of volatiles within the fluid decreased below 1 mol% with no immiscibility. This resulted m total homogenization temperatures of H2O-(CO2-CH4)-NaCl inclusions below 180 degrees C. Hydrogen isotope compositions of methane in fluid inclusion have delta D values of less than -100 parts per thousand in the CH4-zone, typical for an origin through cracking of higher hydrocarbons, but where the methane has not equilibrated with the pore water. delta D values of fluid inclusion water are around -40 parts per thousand., in isotopic equilibrium with phyllosilicates of the whole rocks. Within the CH4 to H2O(CO2) transition zone, delta D(H2O) values in fluid inclusions decrease to -130 parts per thousand interpreted to reflect the contribution of deuterium depleted water from methane oxidation. In the H2O-zone, delta D(H2O) values increase again towards an average of -30 parts per thousand which is again consistent with isotopic equilibrium with host-rock phyllosilicates. delta C-13 values of methane in fluid inclusions from the CH4-zone are around -27 parts per thousand in isotopic equilibrium with calcite in veins and whole rocks. The delta C-13(CH4) values decrease to less than -35 parts per thousand at the transition to the H2O-zone and are no longer in equilibrium with the carbonates in the whole rocks. delta C-13 values of CO, are variable but too low to be in equilibrium with the wall rock fluids, compatible with a contribution of CO2 from closed system oxidation of methane. Differences in isotopic composition between host-rock and Alpine fissure carbonate are generally small, suggesting that the amount of CO2 produced by oxidation of methane was small compared to the C-budget in the rocks and local pore fluids were buffered by the wall rocks during precipitation of calcite within the fissures. (c) 2006 Elsevier B.V. All rights reserved.
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Marijuana is the most widely used illicit drug, however its effects on cognitive functions underling safe driving remain mostly unexplored. Our goal was to evaluate the impact of cannabis on the driving ability of occasional smokers, by investigating changes in the brain network involved in a tracking task. The subject characteristics, the percentage of Δ(9)-Tetrahydrocannabinol in the joint, and the inhaled dose were in accordance with real-life conditions. Thirty-one male volunteers were enrolled in this study that includes clinical and toxicological aspects together with functional magnetic resonance imaging of the brain and measurements of psychomotor skills. The fMRI paradigm was based on a visuo-motor tracking task, alternating active tracking blocks with passive tracking viewing and rest condition. We show that cannabis smoking, even at low Δ(9)-Tetrahydrocannabinol blood concentrations, decreases psychomotor skills and alters the activity of the brain networks involved in cognition. The relative decrease of Blood Oxygen Level Dependent response (BOLD) after cannabis smoking in the anterior insula, dorsomedial thalamus, and striatum compared to placebo smoking suggests an alteration of the network involved in saliency detection. In addition, the decrease of BOLD response in the right superior parietal cortex and in the dorsolateral prefrontal cortex indicates the involvement of the Control Executive network known to operate once the saliencies are identified. Furthermore, cannabis increases activity in the rostral anterior cingulate cortex and ventromedial prefrontal cortices, suggesting an increase in self-oriented mental activity. Subjects are more attracted by intrapersonal stimuli ("self") and fail to attend to task performance, leading to an insufficient allocation of task-oriented resources and to sub-optimal performance. These effects correlate with the subjective feeling of confusion rather than with the blood level of Δ(9)-Tetrahydrocannabinol. These findings bolster the zero-tolerance policy adopted in several countries that prohibits the presence of any amount of drugs in blood while driving.
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In the present work are reported investigations of structural, magnetic and electronic properties of GaAs/Ga1-xInxAs/GaAs quantum wells (QW) having a 0.5 - 1.8 monolayer thick Mn layer, separated from the quantum well by a 3 nm thick spacer. The structure of the samples is analyzed in details by photoluminescence and high-resolution X-ray difractometry and reflectometry, confirming that Mn atoms are practically absent from the QW. Transport properties and crystal structure are analyzed for the first time for this type of QW structures with so high mobility. Observedconductivity and the Hall effect in quantizing magnetic fields in wide temperature range, defined by transport of holes in the quantum well, demonstrate properties inherent to ferromagnetic systems with spin polarization of charge carriersin the QW. Investigation of the Shubnikov ¿ de Haas and the Hall effects gave the possibility to estimate the energy band parameters such as cyclotron mass andFermi level and calculate concentrations and mobilities of holes and show the high-quality of structures. Magnetic ordering is confirmed by the existence of the anomalous Hall effect.
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OBJECTIVES: Long occlusions in calcified crural arteries are a major cause of endovascular technical failure in patients with critical limb ischaemia. Therefore, distal bypasses are mainly performed in patients with heavily calcified arteries and with consequently delicate clamping. A new reverse thermosensitive polymer (RTP) is an alternative option to occlude target vessels. The aim of the study is to report our technical experience with RTP and to assess its safety and efficiency to temporarily occlude small calcified arteries during anastomosis time. METHODS: Between July 2010 and December 2011, we used RTP to occlude crural arteries in 20 consecutive patients with 20 venous distal bypasses. We recorded several operative parameters, such as volume of injected RTP, duration of occlusion and anastomotic time. Quality of occlusion was subjectively evaluated. Routine on-table angiography was performed to search for plug emboli. Primary patency, limb salvage and survival rates were reported at 6 months. RESULTS: In all patients, crural artery occlusion was achieved with the RTP without the use of an adjunct occlusion device. Mean volume of RTP used was 0.3 ml proximally and 0.25 ml distally. Mean duration of occlusion was 14.4 ± 4.5 min, while completion of the distal anastomosis lasted 13.4 ± 4.3 min. Quality of occlusion was judged as excellent in eight cases and good in 12 cases. Residual plugs were observed in two patients and removed with an embolectomy catheter, before we amended the technique for dissolution of RTP. At 6 months, primary patency rate was 75% but limb salvage rate was 87.5%. The 30-day mortality rate was 10%. CONCLUSIONS: This study shows that RTP is safe when properly dissolved and effective to occlude small calcified arteries for completion of distal anastomosis.
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RESUME Les follicules des vibrisses des rongeurs sont représentés sous la forme d'une carte topographique dans le cortex à tonneaux. Lorsque un groupe de vibrisses est coupé pendant plusieurs jours chez un rongeur adulte, en laissant les autres vibrisses intactes, le champ réceptif des neurones du cortex à tonneaux est modifié, ce qui démontre que les cartes corticales sont plastiques. Dans notre étude, une expérience sensorielle a été induite chez une souris adulte se comportant librement en stimulant chroniquement une de ses vibrisses pendant 24h. Par une analyse des potentiels de champ locaux, nous démontrons que les caractéristiques spatiotemporelles du flux d'excitation évoqué par la vibrisse principale (VP) dans la colonne corticale correspondante à la vibrisse stimulée n'est pas altéré. Par contre, l'enregistrement des potentiels d'actions d'un total de 1041 neurones à travers le cortex à tonneaux révèlent plusieurs modifications de l'activité neuronale. L'activité spontanée ainsi que la réponse évoquée par la VP sont déprimées dans la colonne corticale stimulée (nombre moyen de potentiels d'action évoqués par la VP diminue de 25 % et 36% dans la couche IV et les couches II&III). La réponse des neurones à la vibrisse stimulée diminue également dans les colonnes corticales adjacentes, «non-stimulées». La dépression de l'activité spontanée et de la réponse à la VP est localisée à la colonne corticale stimulée. Dans le tonneau stimulé, la première partie de la réponse à la VP n'est pas affaiblie, démontrant que la dépression de la réponse n'est pas due à un phénomène de plasticité sous-corticale ou thalamocorticale. La stimulation chronique d'une vibrisse entraîne une augmentation du nombre de synapses GABAergiques dans la couche IV du tonneau correspondant (Knott et al, 2002). Dès lors, nos résultats suggèrent qu'une augmentation de l'inhibition dans le tonneau stimulé serait à l'origine de la diminution des potentiels d'action évoqués par la vibrisse stimulée et en conséquence de l'amplitude du flux d'excitation vers les couches II&III puis vers les colonnes corticales adjacentes. Toutes les réponses des neurones du tonneau stimulé ne sont pas déprimées. Les réponses des neurones à la vibrisse voisine caudale à VP diminuent dans la couche IV (42%) et dans les couches II&III (52%) mais pas les réponses aux 7 autres vibrisses voisines. Les entrées synaptiques en provenance de la vibrisse caudale pourraient avoir été spécifiquement déprimées en raison d'une décorrélation prolongée entre l'activité évoquée dans les chemins sensoriels relatifs à la vibrisse stimulée et à la vibrisse caudale, spécificité qui découlerait du fait que, parmi les vibrisses voisines à la VP, la vibrisse caudale génère les réponses les plus fortes dans la colonne corticale. Quatre jours après l'arrêt de la stimulation, l'activité neuronale n'est plus déprimée; au contraire, nous observons une potentiation des réponses à la VP dans la couche IV de la colonne corticale stimulée. De plus, nous montrons que l'expression des protéines GLT-1 et GLAST, deux transporteurs astrocytaires du glutamate, est augmentée de ~2.5 fois dans la colonne corticale stimulée, indiquant l'existence d'une «plasticité gliale» et suggérant que les cellules gliales participent activement à l'adaptation du cerveau à l'expérience. ABSTRACT In the barrel cortex, mystacial whisker follicles are represented in the form of a topographie map. The selective removal of a set of whiskers while sparing others for several days in an adult rodent alters receptive field of barrel cortex neurons, demonstrating experience-dependent plasticity of cortical maps. Here sensory experience was altered by chronic stimulation of a whisker for a 24h period in a freely behaving adult mouse. By means of an evoked local field potential analysis, we show that chronic stimulation does not alter the flow of excitation evoked by the principal whisker (PW) in the stimulated barrel column. However, the recording of neuronal firing from a total of 1041 single units throughout the barrel cortex reveals several changes in neuronal activity. Immediately after chronic stimulation, spontaneous activity as well as PW-responses are depressed in the stimulated barrel column (mean number of spikes per PW-deflection decreases by 25% and 36% in layer IV and layers II&III, respectively). Neuronal responses towards the chronically stimulated whisker are also significantly depressed in layers II&III of the adjacent "non-stimulated" barrel' columns. The depression of both spontaneous activity and PW-responses are restricted to the stimulated ban-el column. The earliest time epoch of the PW-response in the stimulated barrel is not depressed, demonstrating that the decrease of cortical responses is not due to subcortical or thalamocortical plasticity. The depression of PW-response in the stimulated barrel correlates with an increase in the number of GABAergic synapses in layer IV (Knott et al., 2002). Therefore, our results suggest that an increase in inhibition within the stimulated barrel may reduce its excitatory output and accordingly the flow of excitation towards layers and the subsequent horizontal spread into adjacent barrel columns. Not all responses of neurons in the stimulated barrel are depressed. Neuronal responses towards the caudal in-row whisker decrease by 42% in layer IV and 52% in layers MM but responses to the other 7 immediate surround whiskers (SWs) are not affected. The synaptic inputs from the SW that elicit the strongest responses in the stimulated barrel may have been specifically depressed following a prolonged period of diminished coherence between neuronal activity evoked in the pathways from the chronically stimulated whisker and from its surrounding in-row whisker. Four days after the cessation of the stimulation, depression of neuronal activity is no longer present; on the contrary, we observe a small but significant potentiation of PW-responses in layer IV of the stimulated barrel column. Moreover we show that the expression of astrocytic glutamate transporters GLT-1 and GLAST proteins were both upregulated by ~2.5 fold in the stimulated barrel column, which indicates that glial cells exhibit experience-dependent functional changes and could actively take part in the adaptation of the cerebral cortex to experience.