• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 39
  • 32
  • 19
  • 10
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 148
  • 37
  • 32
  • 26
  • 15
  • 13
  • 13
  • 12
  • 11
  • 11
  • 11
  • 10
  • 10
  • 10
  • 9
  • 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.
31

Avaliações radiográficas dos membros torácicos e pélvicos de saguis (Callithrix sp.).

Siragusi, Rafael Henrique de Souza January 2019 (has links)
Orientador: Sheila Canevese Rahal / Resumo: O objetivo do presente estudo foi avaliar radiograficamente os membros torácicos e pélvicos de um grupo de saguis mantidos em cativeiro, oriundos de apreensões realizadas para o combate do tráfico ilegal de animais. Foram utilizados 14 saguis, sendo 12 adultos e dois juvenis, oito machos e seis fêmeas, com massa corpórea entre 248 e 354 gramas, sendo um sagui-de-tufo-branco (Callithrix jacchus), oito saguis-de-tufo preto (Callithrix penicillata) e cinco saguis híbridos (Callithrix sp.). Com exceção de três saguis que estavam radiograficamente normais, todos os demais apresentaram alterações radiográficas dos membros, pélvicos e/ou torácicos. A despeito das alterações, a maioria dos animais conseguia se locomover sem grandes limitações no cativeiro. Dos 11 saguis com alterações no membro pélvico, cinco (45,45%) apresentavam estreitamento pélvico e desvio varo bilateral do fêmur, sendo um sugestivo de raquitismo e um de osteomalácia. Os demais apresentaram alterações, tais como má-consolidação de fratura acetabular com osteoartrite da cabeça femoral, amputação parcial de membro, antecurvato de ambas as tíbias, osteoartrite do joelho, entre outros. Seis saguis (54,54 %) mostraram alteração no membro torácico, tais como fratura do rádio, subluxação escápulo-umeral e incongruência da articulação úmero-radio-ulnar, entre outros. Foi possível concluir que 78,57% dos saguis avaliados tinham alterações ósseas e/ou articulares detectadas radiograficamente, que foram predominantes nos m... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to provide a radiographic evaluation of the fore- and hind limbs of marmosets in captivity, originated from capture carried out to combat illegal wildlife trade. A total of 14 marmosets, 12 adults and two juveniles, eight males and six females, weighing between 248 and 354 grams were used, including one common marmoset (Callithrix jacchus), eight black-pencilled marmoset (Callithrix penicillata) and five hybrid marmosets (Callithrix sp.). Except three marmosets radiographically normal, all the others showed radiographic changes of the forelimbs and/or hind limbs. Despite the changes, most primates were capable of moving without major limitations in captivity. Of the 11 marmosets with radiographic changes of the hind limbs, five (45.45%) had pelvic narrowing and bilateral varus deviation of the femur, which had one suggestive of rickets and one of osteomalacia. The other marmosets had changes such as malunion of acetabular fracture with hip osteoarthritis, transtíbial amputation, antecurvatum of both tibias, and knee osteoarthritis, among others. Six marmosets (54.54%) showed alterations in the forelimbs, such as radius fracture, scapulohumeral subluxation, and bilateral humeral-radio-ulnar joint incongruence, among others. In conclusion, 78.57% of the evaluated marmosets had bone and/or joint changes detected by plain radiograph, which were found predominantly in the hind limbs and without impediment to locomotion in captivity. / Mestre
32

Morphologische Entwicklung und Zytokinproduktion von humanen Präimplantationsembryonen / Morphology and Cytokine production in human preimplantation embryos

Bischofs, Sonja Julia January 2011 (has links) (PDF)
In Deutschland unterliegt die Reproduktionsmedizin umfassenden gesetzlichen Regelungen. Fertilisierte Oozyten müssen im Pronukleus-Stadium selektiert werden, hierbei darf maximal eine Anzahl von drei Embryonen kultiviert werden. Studien der vergangenen Jahre zielten vornehmlich auf die Entwicklung eines detaillierten Scoring-Systemes (Zygoten Screening im Pronukleus Stadium), um jeweils die Embryonen mit dem größten Entwicklungspotenzial zu selektieren. 99 Patientinnen wurden inkludiert und durchliefen entweder eine IVF oder ICSI Prozedur. Die fertilisierten Oozyten wurden im Pronukleus-Stadium beurteilt. TNF alpha und LIF, beides in der Reproduktionsmedizin bekannte Zytokine, wurden in gepoolten Kulturmedien an den Tagen 3 und 5 gemessen. 865 Oozyten wurden hierbei gewonnen, 438 zeigten positive Fertilisations-Zeichen, es fand sich eine Fertilisationsrate von 62,6%. Die Schwangerschaftsrate betrug 24,7%. Die mittlere PN Scores zeigten sich signifikant niedriger bei nicht konzipierenden Frauen (15.8 versus 17.2). Die mittlere TNF alpha Konzentration zeigte sich sowohl an Tag 3 als auch an Tag 5 signifikant erniedrigt in schwangeren Frauen gegenüber denen, welche nicht konzipierten (0.43pg/ml versus 0.59pg/ml). Die mittlere LIF Konzentration hingegen war signifikant erhöht bei schwangeren Frauen (56.2pg/ml versus 22.2pg/ml an Tag 3). Zusammenfassung: Das PN-Scoring bleibt eine gute Methode zur prognostischen Einschätzung des weiteren Entwicklungspotenziales von Präimplantationsembryonen. Höhere Konzentrationen von LIF und niedrigere Konzentrationen von TNF alpha in Kulturmedien scheinen eine favorable Rolle in der Embryogenese zu spielen. / German law comprehensively regulates IVF procedures and the selection of embryos for further cultivation. By law, fertilized oocytes have to be selected at the pronucleus-stadium, and a maximum of three embryos are allowed to be cultivated. Studies of the past years therefore aimed to elaborate a detailed scoring system (zygote scoring system at the pronucleus stage) in order to select those embryos with the highest potential for further favorable development. METHODS: 99 patients were included in our prospective trial and underwent either IVF or ICSI procedure. Fertilized oocytes were assessed at the pronucleus stage (day 1). TNF alpha and LIF, both cytokines known to be involved in embryonic development, were measured in pooled culture media on day 3 and 5. RESULTS: A total of 865 oocytes were collected, 438 showed positive signs of fertilisation, a fertilisation-rate of 62.6 % was achieved. Pregnancy rate per embryo transfer was 24.7 %. Mean PN-scores were significantly lower in women conceiving (15.8) than in those not conceiving (17.2). Mean TNF alpha concentration in culture media on day 3 was 0,54pg/ml and 0.37pg/ml on day 5 and was significantly lower in women conceiving (0.43pg/ml versus 0.59pg/ml on day 3). Mean LIF concentration on day 3 was 31.5pg/ml and 35.5pg/ml on day 5 and was significantly higher in women conceiving (56.2pg/ml versus 22.2pg/ml on day 3). CONCLUSION: PN-scoring remains a valuable tool for assessing fertilized oocytes for their further developmental potential at the pronucleus stage. Higher concentrations of LIF and lower concentrations of TNF alpha in culture media seem to play a putative favorable role in embryogenesis.
33

Laser-induced fluorescence measurements of dual plumes and comparison of laser-induced fluorescence and conductivity probe measurements

Chrzan, Joseph Coleman 10 July 2012 (has links)
The laser-induced fluorescence (LIF) technique is used to visualize and quantify the concentration field around a conductivity probe. The LIF data are compared to the signal collected by the conductivity probe. The objective is to compare the signal of the contact-sensor to the "ground-truth" measurement of the LIF data. Detailed comparison of the temporal response and the peak detection are presented. In addition, a proof-of-concept of a two-color LIF technique is presented using Rhodamine 6G paired with an Argon-ion laser and simultaneously Oxazine 725 paired with a Krypton-ion laser. Optical filters on two digital cameras isolate the emitted light from these respective laser/dye combinations. The objective is to provide detailed quantitation of two over-lapping (non-reactive)chemical plumes.
34

Burning velocity and OH concentration in premixed combustion

Yamashita, H., Hayashi, N., Ozeki, M., Yamamoto, K. January 2009 (has links)
No description available.
35

Local flame structure and turbulent burning velocity by joint PLIF imaging

Ohnishi, Masahiro, Isii, Shinji, Yamamoto, Kazuhiro January 2011 (has links)
No description available.
36

C60:LiF Hole Blocking Layer for Bulk-heterojunction Solar Cells

Gao, Dong 31 December 2010 (has links)
A standard procedure for P3HT:PCBM bulk-heterojunction solar cells has been developed. Fabrication conditions, such as environment; solution concentration, thickness of active layer or post-treatment methods are systematically optimized. The best device performance is obtained by slow-drying spin-coated P3HT:PCBM (1:0.8) blend layer with DCB as solvent. C60:LiF composite films with up to 80% LiF concentration as hole blocking layer have been developed to significantly increase power conversion efficiencies of OPV devices. The short-circuit current density is greatly enhanced, without sacrificing open-circuit voltage and fill factor. Due to its superior oxygen diffusion blocking effect, the C60:LiF composite layer also can provide a more effective passivation film than a thin LiF layer, resulting in an impressive enhancement in air stability of devices.
37

C60:LiF Hole Blocking Layer for Bulk-heterojunction Solar Cells

Gao, Dong 31 December 2010 (has links)
A standard procedure for P3HT:PCBM bulk-heterojunction solar cells has been developed. Fabrication conditions, such as environment; solution concentration, thickness of active layer or post-treatment methods are systematically optimized. The best device performance is obtained by slow-drying spin-coated P3HT:PCBM (1:0.8) blend layer with DCB as solvent. C60:LiF composite films with up to 80% LiF concentration as hole blocking layer have been developed to significantly increase power conversion efficiencies of OPV devices. The short-circuit current density is greatly enhanced, without sacrificing open-circuit voltage and fill factor. Due to its superior oxygen diffusion blocking effect, the C60:LiF composite layer also can provide a more effective passivation film than a thin LiF layer, resulting in an impressive enhancement in air stability of devices.
38

Dissecting the paracrine interactions contributing to normal testicular function and during the ageing process

Curley, Michael Kings January 2018 (has links)
The mammalian testis is divided into two distinct compartments which carry out its principal functions. Spermatogenesis occurs within the seminiferous tubules and androgen biosynthesis primarily occurs in the interstitial space. Both these processes are entirely dependent upon the two major testicular somatic cell populations - the Sertoli and Leydig cells respectively. In human males, testicular spermatogenic and endocrine function declines during the ageing process. Of particular significance is the reported age-related decrease in Leydig cell androgen production as androgens have been suggested to play a crucial role in supporting lifelong general health in men, with low circulating testosterone linked to an increased risk of developing chronic age-related cardiometabolic diseases. However, the relationship between ageing, testicular function and disease is not fully understood, impeding the development of novel therapeutic strategies to treat age-related testicular dysfunction. In one set of studies undertaken herein, a series of novel mouse models of premature ageing were utilised to begin to dissect the process of age-related testicular degeneration. Firstly, a novel knockout-first conditional allele of a previously reported premature-ageing model driven by Cisd2 (CDGSH Iron Sulphur Domain 2) deficiency was validated and the testicular phenotype characterised and compared to that of naturally aged mice at 18-months of age. Histological analyses revealed premature testicular atrophy at 6-months of age in CISD2 deficient mice, consistent with observations of the naturally aged testis. Circulating testosterone was significantly lower in CISD2-deficient mice compared to wild-type controls at 6-months of age and the luteinising hormone/testosterone ratio was significantly elevated, indicative of compensated Leydig cell failure. mRNA expression of key genes involved in androgen production were also significantly reduced in the CISD2-deficient testis, pointing to Leydig cell dysfunction in this model of premature aging. Next, Cre/LoxP technology was used to delete Cisd2 from specific testicular cell populations to determine which cell types control/support Leydig cell function during the ageing process. Testosterone production was unaffected when Cisd2 was disrupted in either the Leydig cell population or Sertoli cell population. These observations suggest that disruption to the testicular microenvironment in which Leydig cells reside, rather than intrinsic Leydig cell ageing, may play a significant role in age-associated Leydig cell dysfunction. A second set of studies were carried out to investigate the role of leukemia inhibitory factor (LIF) signalling in the maintenance of testicular function. LIF is a pleiotropic cytokine belonging to the interleukin-6 family. In the rodent testis, LIF is expressed in fetal life and adulthood; the peritubular myoid cells thought to be the main site of production. Given their anatomical location within the testis, LIF produced by peritubular myoid cells may act on both intratubular and interstitial cells to influence spermatogenesis and steroidogenesis respectively. Indeed, LIFR is expressed in germ cells, Sertoli cells, Leydig cells as well as testicular macrophages suggesting that LIF may be a key paracrine regulator of testicular function. However, the precise role of LIF/LIFR signalling in the testis is largely unknown. As such, models of testicular cell-specific Lifr deletion were generated using Cre/LoxP technology. Analysis of these novel models of conditional LIFR ablation revealed that LIFR is dispensable in germ cells for normal spermatogenesis. However, LIFR ablation from Sertoli cells resulted in a progressive degenerative phenotype, characterised by abnormal germ cell loss, sperm stasis, seminiferous tubule distention and subsequent atrophy of the seminiferous tubules. In a final set of studies, a rat model of Leydig cell ablation-regeneration was used to determine the regenerative capacity of human adipose-derived perivascular stem cells (hAd-PSC) as a potential therapy for testicular dysfunction. Following ethane dimethanesulphonate (EDS) mediated Leydig cell ablation, primary hAd-PSCs, cultured with or without LH, IGF-1, PDGFBB, T3 and ITS supplement, were transplanted into the rat testis and Leydig cell regeneration was monitored via serial measurements of circulating luteinising hormone (LH) and testosterone. Overall, hAd- PSCs had no impact on the recovery of circulating testosterone levels. However, when pre-cultured with the cocktail of hormone/growth factor supplements, the LH spike induced by the removal of testosterone negative feedback was dampened, suggesting the transplanted cells may promote Leydig cell regeneration. Whether these cells differentiate into Leydig cells, or simply provide paracrine support to the regenerating Leydig cells remains to be determined. Although Ad-PSCs may enhance regeneration kinetics, the transplanted cells were undetectable in the testis 5 weeks post transplantation suggesting they may not survive in the context of long term xenogeneic transplantation.
39

Extraction des actinides et des lanthanides du combustible du réacteur rapide à sels fondus / Fuel reprocessing of the fast molten salt reactor : actinides et lanthanides extraction

Jaskierowicz, Sebastien 29 November 2012 (has links)
Le procédé de traitement du combustible du réacteur à sels fondus (réacteur de génération IV) est un procédé multi-étape dans lequell’extraction des actinides et des lanthanides utilise la technique d’extraction réductrice. Le développement d’un modèle analytique a montré que la mise en contact du sel combustible LiF-ThF4 avec une phase métallique constituée d'un mélange Bi-Li permet l’extraction sélective et quantitative des actinides dans un premier temps, puis l’extraction quantitative des lanthanides dans un second temps. La maitrise de ce procédé nécessite la connaissance des caractéristiques des phases salines impliquées dans le procédé. Les études des propriétés physico-chimiques des sels fluorures fondus ont permis de développer une technique de mesure de la fluoroacidité dans ces milieux via une mesure potentiométrique. Cette technique a permis d’établir un classement de différents mélanges de fluorures fondus en fonction de leur acidité relative. Par ailleurs, une méthode de détermination de la solvatation de solutés dans ces milieux a également été développée par électrochimie afin d’approfondir la connaissance du sel combustible (en particulier solvatation de ThF4 par les ions F-).L'extraction réductrice met également en jeu une phase métallique liquide. Une technique de préparation de cette phase a été développée par électro-réduction de lithium sur une électrode liquide de bismuth en milieu LiCl-LiF. Cette technique permet un bon contrôle de la fraction molaire de lithium introduite dans le bismuth, paramètre essentiel à l’efficacité de l’extraction.Enfin, afin d'optimiser le procédé général de traitement multi-étapes, des méthodes électrochimiques ont été proposées afin de régénérer les différentes phases liquides (salines et métalliques) mise en jeu lors de l’extraction. / The fuel reprocessing of the molten salt reactor (Gen IV concept) is a multi-steps process in which actinides and lanthanides extraction is performed by a reductive extraction technique. The development of an analytic model has showed that the contact between the liquid fuel LiF-ThF4 and a metallic phase constituted of Bi-Li provide firstly a selective and quantitative extraction of actinides and secondly a quantitative extraction of lanthanides. The control of this process implies the knowledge of saline phase properties. Studies of the physico-chemical properties of fluoride salts lead to develop a technique based on potentiometric measurements to evaluate the fluoroacidity of the salts. An acidity scale was established in order to classify the different fluoride salts considered.Another electrochemical method was also developed in order to determine the solvation properties of solutes in fluoride F- environment (and particularly ThF4 by F-)In reductive extraction technique, a metallic phase is also involved. A method to prepare this phase was developed by electro-reduction of lithium on a bismuth liquid cathode in LiCl-LiF melt. This technique allows to accurately control the molar fraction of lithium introduced into the liquid bismuth, which is a main parameter to obtain an efficient extraction.
40

Blood Vitronectin Is a Major Activator of LIF and IL-6 in the Brain Through Integrin-FAK and uPAR Signaling

Keasey, Matthew P., Jia, Cuihong, Pimentel, Lylyan F., Sante, Richard R., Lovins, Chiharu, Hagg, Theo 01 February 2018 (has links)
We defined how blood-derived vitronectin (VTN) rapidly and potently activates leukemia inhibitory factor (LIF) and pro-inflammatory interleukin 6 (IL-6) in vitro and after vascular injury in the brain. Treatment with VTN (but not fibrinogen, fibronectin, laminin-111 or collagen-I) substantially increased LIF and IL-6 within 4 h in C6-astroglioma cells, while VTN-/- mouse plasma was less effective than that from wild-type mice. LIF and IL-6 were induced by intracerebral injection of recombinant human (rh)VTN in mice, but induction seen upon intracerebral hemorrhage was less in VTN-/- mice than in wild-type littermates. In vitro, VTNeffects were inhibited by RGD, αvβ3 and αvβ5 integrin-blocking peptides and antibodies. VTN activated focal adhesion kinase (FAK; also known as PTK2), whereas pharmacological- or siRNA-mediated inhibition of FAK, but not PYK2, reduced the expression of LIF and IL-6 in C6 and endothelial cells and after traumatic cell injury.Dominant-negative FAK (Y397F) reduced the amount of injury-induced LIF and IL-6. Pharmacological inhibition or knockdown of uPAR (also known as PLAUR), which binds VTN, also reduced cytokine expression, possibly through a common target of uPAR and integrins. We propose that VTN leakage into tissues promotes inflammation. Integrin-FAKsignaling is therefore a novel IL-6 and LIF regulation mechanism relevant to the inflammation and stem cell fields.

Page generated in 0.0155 seconds