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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Estudos anatômicos, ultra-estruturais e bioquímicos da síndrome Kranz em folhas de duas espécies de Gomphrena L. (Amaranthaceae) / Anatomical, ultrastructural and biochemical surveys in leaves to two Gomphrena L. species (Amaranthaceae)

Natalia Paganotti Antonucci 10 March 2010 (has links)
A síndrome Kranz é um conjunto de características anatômicas, ultra-estruturais e bioquímicas que culminam na realização da fotossíntese C4. Tal síndrome apresenta grande diversidade dentre as Angiospermas, tornando-se conveniente seu estudo em todos os níveis acima citados para a completa caracterização da mesma. No presente trabalho foi investigada a síndrome Kranz de Gomphrena arborescens e G. scapigera (Amaranthaceae) com ênfase na origem ontogenética da bainha Kranz, na descrição ultra-estrutural e na confirmação bioquímica sobre o tipo de fotossíntese C4. O desenvolvimento foliar dessas espécies indica que a bainha Kranz é originada da camada mais interna do mesofilo, a endoderme foliar. Uma discussão sobre os termos presentes na literatura para a descrição dessa bainha, todos eles focados em sua função na fotossíntese C4, demonstra a importância de se utilizar termos que informem a origem ontogenética dessa bainha, como endoderme e periciclo. Na análise ultra-estrutural, foram identificados possíveis fatores que interferem na fotossíntese de ambas as espécies, como o espessamento e a composição da parede da bainha Kranz, o posicionamento centrípeto dos cloroplastos e a presença de retículo periférico nos mesmos. Embora a análise bioquímica tenha resultado em informações ainda não conclusivas, o dimorfismo dos cloroplastos sugere a realização da fotossíntese C4 do tipo NADP-ME. O presente trabalho, de uma forma geral, contribui ao conhecimento da síndrome Kranz dentre as Amaranthaceae s.s., um grupo em que a ultra-estrutura e a bioquímica ainda são pouco conhecidas, e ressalta a importância dos estudos anatômicos, principalmente com enfoque ontogenético, para o melhor conhecimento da diversidade da síndrome Kranz dentre as Angiospermas. / The Kranz syndrome is a set of anatomical, ultrastructural and biochemical features that culminate in the C4 photosynthesis. This syndrome has a huge diversity among Angiosperms, so it became suitable to survey all the levels above cited for its complete characterization. In the present work the Kranz syndrome of Gomphrena arborescens and G. scapigera (Amaranthaceae) is studied, with emphasis on the ontogenetic origin of the Kranz sheath, on the ultrastructural description, and on the biochemical confirmation about the C4 photosynthesis kind. The foliar development of these species shows that the Kranz sheath is originated from the inner layer of the mesophyll, the foliar endodermis. A discussion about the literature terms used to describe the Kranz sheath, all of them referring to the function of this layer in C4 photosynthesis, demonstrates the importance of using terms that inform the ontogenetic origin of this layer, such as endodermis and perycicle. The ultrastructural analysis identified possible factors that interfere on the C4 photosynthesis of both species, such as wall thickening and composition of Kranz sheath cells, the centripetal position of chloroplasts and the peripheral reticulum in chloroplasts. Although biochemical analysis has resulted in no conclusive information, the chloroplast dimorphism suggests the NADP-ME C4 photosynthesis. This work, in a general way, contributes to the knowledge of the Kranz syndrome among Amaranthaceae s.s., a group that has the ultrastructure and the biochemistry of C4 photosynthesis poorly known. It also draws attention to the importance of anatomical surveys concerning the ontogenetic origin of Kranz sheath for a better understanding on the diversity of Kranz syndrome among Angiosperms.
102

Gradients in the mechanical properties of auditory hair cells / Gradients dans les propriétés mécaniques de la touffe ciliaire des cellules sensorielles auditives de l’oreille interne

Tobin, Mélanie 25 November 2016 (has links)
Notre capacité à communiquer et à apprécier la musique repose sur une discrimination de fréquences couvrant une large gamme de fréquences sonores. Cette propriété résulte de cellules mécanosensorielles « ciliées », qui sont réglées pour répondre de façon maximale à une fréquence caractéristique qui varie monotoniquement le long de l’axe de l’organe auditif, la cochlée. Les mécanismes cellulaires et moléculaires qui définissent la fréquence d’une cellule ciliée et régulent sa valeur pour différentes cellules afin de couvrir la gamme auditive demeurent néanmoins inconnus. Notre hypothèse de travail est que cette fréquence est réglée en partie par les propriétés mécaniques passives et actives de la « touffe ciliaire », l’antenne mécanosensorielle de la cellule ciliée. A l’aide d’une préparation excisée de la cochlée du rat, nous avons combiné l’iontophorèse de chélateurs de calcium (BAPTA ou EDTA) pour casser les liens de bout-de-cil qui connectent les stéréocils voisins de la touffe ciliaire, une stimulation grâce à un micro-jet de fluide pour estimer la raideur de la touffe ciliaire et des enregistrements en « patch-clamp » de courants de transduction afin de compter le nombre de liens de bout-de-cil intacts qui contribuent à la réponse. Avec les mouvements évoqués par la rupture des liens de bout-de-cil et avec nos mesures de raideur, nous avons pu estimer la tension dans toute la touffe ciliaire, ainsi que la tension dans un seul lien de bout-de-cil en connaissant le nombre de liens qui contribuent à cette tension. Dans les cellules ciliées externes, qui sont impliquées dans l’amplification du stimulus sonore mais qui n’envoient pas d’information neuronale au cerveau, nous avons observé un gradient de tension et de raideur lorsque la fréquence caractéristique de la cellule ciliée augmente, suggérant que ces paramètres physiques peuvent être impliqués dans le réglage d’une cellule ciliée à sa fréquence caractéristique. Au contraire, pour les cellules ciliées internes, les vraies cellules sensorielles de la cochlée, nos observations ne montrent pas de gradient significatif. De plus, nous avons observé des mouvements de la touffe ciliaire induits par la variation de la concentration en calcium, correspondant à une tension accrue pour des concentrations en calcium plus faibles. Ces mouvements sont similaires à ceux évoqués dans d’autres classes de vertébrés, tels que chez la grenouille ou chez la tortue. Ainsi, nos résultats réconcilient les expériences faites chez les vertébrés inférieurs et chez le mammifère, et montrent l’implication des gradients de la mécanique de la touffe ciliaire pour l’importante sélectivité fréquentielle de la cochlée / Our ability to communicate and appreciate music relies on acute frequency discrimination over a broad range of sound frequencies. This property results from the operation of mechanosensory “hair" cells, which are each tuned to respond maximally to a characteristic frequency that varies monotonically along the axis of the auditory organ, the cochlea. The cellular and molecular mechanisms that set the characteristic frequency of a hair cell and regulate its value among different cells to cover the auditory range have remained elusive. Our working hypothesis is that tuning results in part from passive and active mechanical properties of the “hair" bundle, the mechanosensory antenna of the hair cell.Using an excised preparation from the rat cochlea, we combined iontophoresis of a calcium chelator (BAPTA or EDTA) to break the tip links that interconnect neighbouring stereocilia of the hair-cell bundle, fluid-jet stimulation to estimate hair-bundle stiffness and patch-clamp recordings of transduction currents to count the number of intact transduction channels contributing to the response. From the movements evoked by tip-link breakage and our stiffness measurements, we were able to estimate tension in the whole hair bundle as well as, knowing the number of tip links contributing to this tension, in a single tip link.In outer hair cells, which are involved in sound amplification but do not send neural information to the brain, we observed a gradient of tension and stiffness from the low-frequency to the high-frequency end of the cochlea, suggesting that these physical parameters may help tune the hair cell to its characteristic frequency. Interestingly, with inner hair cells - the true sensors of the cochlea, our observations do not show any significant gradient. Furthermore, we observed calcium-evoked hair-bundle movements corresponding to an increased tension in the tip links at decreased concentrations of calcium. These movements were similar to those evoked in other classes of vertebrates, such as the frog or the turtle. Together, our results reconcile experiments performed in lower vertebrates with those performed in mammals and show the implication of hair-bundle mechanical gradients in the sharp frequency tuning of the cochlea
103

Unhairing and Fiber bundle-opening of Cowhides using KCl and LiBr/[AMIm]Cl Assisted Neutral Protease for Leather Making

Liu, Hui, Zhang, Qian, Zhang, Yafei, Li, Xiumin, Tang, Keyong, Liu, Jie, Zheng, Xuejing, Pei, Ying 28 June 2019 (has links)
Content: Nowadays, tannery pollution is of great concern worldwide. The unhairing and fiber bundle-opening processes contribute the majority of the pollution by the use of sodium sulfide and calcium hydroxide, which were proposed to be replaced by neutral protease combined with (potassium chloride) KCl, (lithium bromide)LiBr/1-allyl-3-methylimidazolium chloride([AMIm]Cl) in the present work. Proper amount of KCl can speed up the unhairing with the grain not destroyed by the neutral protease. Four methods for unhairing and fiber bundle-opening were used as follows: 1. Two steps in different floats as KCl/neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 2. Two steps in different floats as neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 3. One step in the same float as neutral protease for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. 4. One step in the same float as neutral protease/KCl for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. It was found that using neutral protease/KCl solution for unhairing and LiBr/[AMIm]Cl solution for fiber bundle-opening is the best in fiber bundle-opening at the liming process. Besides, all the methods used here are better than the traditional liming processes (C) from viewpoints of unhairing and fiber bundleopening. Take-Away: 1. The addition of potassium chloride can improve the stability of neutral protease solution. 2. The catalytic efficiency of the enzyme was improved because of adding potassium chloride can enhance the contact rate of neutral protease with substrate. 3. Ionic liquids have less hydrolysis of collagen and larger dissolution of polysaccharides.
104

Effects of different salt-enzymes on opening up of collagen fiber bundles for leather making

Zhang, Yafei, Tang, Zhenye, Liu, Hui, Ferah, Cem Emre, Tang, Keyong 28 June 2019 (has links)
Content: Traditional leather industry involves mechanical, chemical and biological processes, and a lot of leather chemicals are widely used annually. In the beamhouse, especially in liming and re-liming, enormous pollution is usually released because of the traditional use of Na2S and lime. Many researchers have devoted to clean production for leather making. In this study, salt-enzyme liming process was studied in modern leather process to remove the inter-fibrillary matter. Three such salts as Na2SO4, NaCl, and MgCl2 were used with such enzymes as neutral protease and cellulase. The enzyme activity was evaluated by Folin Method. The opening up degree of collagen fiber bundles was observed by SEM and microscopic image of histological staining. The waste water was analyzed. The tannin absorptivity of the samples was evaluated by colorimetry. It was demonstrated that enzyme activity is not affected by salt, but it helps the action of enzymes on hides. Salt might accelerate the penetration of enzymes into the hide to promote the removal of inter-fibrillary and the opening up of collagen fiber bundles. The best fiber opening result was found by SEM at the MgCl2 content of more than 0.4 wt.% in liming. Microscopic observation by histological staining as well as waste water analysis indicated a good removing effect for the inter-fibrillary. This work may provide a cleaner leather making technology. Take-Away: 1.Salt-enzyme liming process was studied in modern leather process to remove the inter-fibrillary matter. 2.To provide theoretical guidance for the clean production of leather.
105

Retrospective analysis of 291 cases of Staphylococcus aureus bacteraemia (SAB) from 06/2017 to 06/2019 at the University Hospital of Leipzig, Germany: Investigation of adherence to the SAB care bundle, effects on mortality, clinical outcomes, and characterization of strains

Gräber, Sandra 12 November 2021 (has links)
From June 2017 to June 2019, 291 cases of Staphylococcus aureus bacteraemia (SAB) were evaluated retrospectively. Patient baseline characteristics, clinical presentations, empiric and targeted treatment, and clinical outcomes were assessed. Our study aimed to evaluate the adherence to a designated SAB care bundle and to assess whether proper adherence improved patient survival. Furthermore, as data for spa type distributions in MSSA-SAB are scarce for Germany, we aimed to describe circulating spa types and spa Clonal Complexes (spa CC) in our epidemiological setting.
106

Discriminability of medial forebrain bundle and ventral tegmental stimulation depends on frequency, but preference does not.

Thompson, Shannon Michele 15 November 2021 (has links)
No description available.
107

Vysoce dostupný škálovatelný CMS v prostředí Java EE / Highly Available Scalable CMS in the Java EE Environment

Šramko, Samuel January 2013 (has links)
This thesis deals with the background of the design of a highly available, scalable and modular content management system based on the Java EE platform and the OSGi framework and with the implementation of the designed system. It describes the design and implementation of the application decomposition to modules, their communication and bindings. Finally, it presents the results of the application testing and proposes available extensions of the application.
108

Sleep Deprivation in the Intensive Care Unit: Lowering Elective Intervention Times

Ross Purdie, La Von Michelle 01 January 2019 (has links)
Sleep deprivation is a multifactorial phenomenon, occurring frequently in the intensive care unit (ICU) and linked to adverse patient healthcare outcomes. The key practice question of this project focused on determining if retiming of routine laboratory and imaging testing outside of the designated “quiet time” can improve sleep quality among adult patients in the ICU. The purpose was to evaluate the effectiveness of implementing an evidence-based intervention to improve sleep quality in the ICU setting. The theoretical framework was the plan-do-study-act model, which offered a process for implementing a practice change and reevaluation of the intervention’s sustainability within the organization. A thorough literature search of over 100 scholarly journal articles, book references, and expert scholarly reports was completed to gain an understanding of this phenomenon in the ICU setting. The Richards-Campbell Sleep Questionnaire (RCSQ) was the data collection tool used to measure improvement in sleep quality. There were 72 participants that are included in the project. The Wilcoxon rank sum and chi square tests were used for the statistical analysis. The findings did not show statistical significance in the improvement in the RCSQ scores after implementation of the intervention. The recommendations include sleep deprivation training for nursing staff and providers, routine use of the RCSQ for data collection, and repeating the study with an increased number of participants and redefined inclusion and exclusion criteria to be more representative of the ICU patient population. The implication for social change is that this project empowers nursing to embrace a leadership role in using evidence-based practice to change clinical guidelines and improve patient outcomes.
109

The existence of infinitely many closed geodesics on a riemannian manifold, containing an isolated prime closed geodesic with maximal index growth

Hasselberger, Hannes 20 October 2017 (has links)
There are two main approaches to solve the problem of finding closed geodesics on a Riemannian manifold M. The variational approach views a closed geodesic as a closed curve which happens to be a geodesic and it looks for critical points of the energy functional, while the dynamical systems approach views a closed geodesic as a geodesic which happens to close up and looks for periodic orbits of the geodesic ow on the unit tangent bundle.
110

An Exploratory Study of the Information Search Stage of the Consumer Decision Process: Based on Elderly Consumers' Selection of a New Housing Bundle

Judd, Vaughan C. (Vaughan Charles) 05 1900 (has links)
This dissertation deals with the decision-to-move process of elderly persons—from a marketer's perspective. The central problem addressed is the lack of empirical knowledge concerning the factors and influences associated with the information search process of elderly persons in making a residential move decision. The purpose was to investigate and understand the key factors and influences which are viewed as important by elderly individuals in their search for and use of information.

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