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Ce projet de recherche a permis d'étudier l'émission d'un rayonnement térahertz (THz) par des antennes photoconductrices (PC) émettrices de type micro-ruban coplanaire. Ces antennes sont fabriquées sur substrats d'arséniure de gallium semi-isolant (GaAs-SI) ou sur ce même substrat ayant subit un traitement d'implantation ionique aux protons suivi d'un recuit thermique (GaAs:H). L'influence de ce procédé de fabrication sur les propriétés du matériau photoconducteur et sur les caractéristiques de l'antenne émettrice a été étudiée. Des mesures de photoconductivité résolue en temps effectuées sur les deux types de substrat montrent que le procédé d'implantation/recuit a eu pour effet de diminuer le temps de vie des photoporteurs de 630 ps à environ 4 ps, tandis que la mobilité n'est réduite que d'un facteur maximum de 1,6. Cette valeur de la mobilité des photoporteurs a par ailleurs été estimée à environ 100 cm$^2$/(V.s) pour le substrat GaAs:H. Les mesures électriques effectuées sur les antennes fabriquées sur les deux types de substrat montrent que le procédé d'implantation/recuit permet d'augmenter la résistivité de la couche active du dispositif d'un facteur 10 (elle passerait de 10$^{8}$ $\Omega$.cm pour le GaAs-SI à 10$^9$ $\Omega$.cm pour le GaAs:H). Les courbes courant-tension, en obscurité et sous illumination, de ces antennes suggèrent également que la densité de pièges profonds est fortement augmentée suite au traitement d'implantation/recuit. L'étude des caractéristiques des diverses antennes a permis de montrer l'intérêt de ce procédé de fabrication. Pour les antennes fabriquées sur GaAs:H, la largeur de bande est améliorée (elle atteint environ 3 THz) et l'amplitude du champ THz émis est augmentée par un facteur 1,4 (dans les mêmes conditions expérimentales). Le rapport signal/bruit des traces THz mesurées sur les antennes les plus performantes est $>$ 200. Une plus grande résistivité et une densité de pièges profonds plus élevée, permet d'appliquer de plus fortes tensions de polarisation sur ces antennes GaAs:H. Finalement, nos résultats ont montré que les améliorations des caractéristiques d'émission de ces antennes THz sont corrélées à la présence d'un champ électrique local plus élevé du coté de l'anode du dispositif.

In der Zeit von Juni 1999 bis März 2001 wurden an der Chirurgischen Klinik Rastatt bei 40 Patienten insgesamt 43 computer- und roboterunterstützte zementfreie Hüfttotalendoprothesen mit dem System CASPAR geplant und implantiert. Von den 43 geplanten Hüftprothesenimplantationen konnten alle 40 Patienten (100%) mit diesem Verfahren operiert werden. 3 Patienten erhielten jeweils im Abstand von 12 Monaten eine zementfreie Hüftprothese mittels CASPAR-Fräsung auf der Gegenseite. Einen Abbruch der Operation aufgrund technischer Probleme fand sich in keinem Fall. In einer mittelfristigen Nachuntersuchung aller Patienten wurden wichtige klinische Parameter wie Schmerzempfinden, Beweglichkeit im Hüftgelenk und Mobilität im täglichen Leben erhoben. Diese Parameter wurden im Harris Hip Score und im Index nach Merle d ́Aubigné zusammengefasst. Zudem erfolgten radiologische Vergleichsaufnahmen als Kontrolle zu den unmittelbar postoperativ erstellten Röntgenbildern. Zusammenfassend ergibt die Auswertung des Harris Hip Score eine Verteilung von 38 Patienten in der Kategorie „sehr gut“ und 2 Patienten in der Kategorie „gut“. In dem Index nach Merle d ́Aubigné zusammengefasst zeigten die Untersuchungen ebenfalls ausgesprochen gute Ergebnisse. Hier fanden sich 36 Patienten in der Kategorie „sehr gut“. Die restlichen 4 Patienten erfüllten die Kriterien für ein „gut“. Dieses hervorragende outcome schlug sich in der Patientenzufriedenheit nieder. Die Bewegungsausmaße der mittels roboterassistierten Hüfte zeigten sehr gute Werte. In diesem Zusammenhang konnte auch in keinem Fall eine Schädigung mit Beeinträchtigung der pelvitrochantären Muskulatur festgestellt werden. Ein positives Trendelenburg- Zeichen fand sich bei keinem von uns mit CASPAR operierten Patienten. Die radiologischen Ergebnisse der robotergefrästen zementfrei implantierten Hüfttotalendoprothesen ergaben sehr gute Ergebnisse. Eine Lockerung oder Schaftsinterung konnte ebenso wenig wie eine Fehlpositionierung des Prothesenschaftes festgestellt werden. Insgesamt erbringt die Nachuntersuchung unserer mittels CASPAR-assistierten Patienten weitaus weniger Komplikationen als zum Teil in der Literatur beschrieben. Insbesondere die häufig erwähnten Weichteilschäden und Bewegungseinschränkungen, die durch Roboter verursacht sind, können wir nicht nachvollziehen. / A total of 43 computer- and robot-assisted cementless total hip endoprostheses were implanted into 40 patients using the CASPAR system at the Surgical Clinic in Rastatt between June 1999 and March 2001. Of the 43 planned hip prosthesis implants, all 40 patients (100 %) could be operated on using this approach. After a 12 month interval, 3 of the patients also received a cementless hip prosthesis on the opposite side by CASPAR-milling. There were no cases of surgical failure due to technical problems. In a midterm postoperative follow-up of all patients, all important clinical parameters such as pain, hip joint flexibility, as well as general mobility were examined. These parameters were summarized in the Harris Hip score and in the scoring system according to Merle d’Aubigné and Postel. In addition, comparison radiographs served as controls to the immediately postoperative X-Rays. In summary, an analysis of the Harris Hip score showed a distribution of 38 patients in the category “very good” and 2 patients in the category “good”. The follow-up results were also markedly good according to the Merle d’Aubigné and Postel scoring system. Here, 36 patients were assigned to the category “very good”, while the other 4 patients satisfied the criteria for “good”. This outstanding outcome was reflected in patient satisfaction. The movement data of the robot-assisted hip were very good. In this context there were no cases of impairment of the musculature of the pelvis-trochanter. There were also no positive Trendelenburg’s signs found with any of our CASPAR operated patients. In conclusion, the robot-assisted cementless total hip arthroplasties yielded very good results. A stem loosening or subsidence or a false positioning of the stem shaft could also not be found. Altogether, the post-operative checkup of our CASPAR-assisted patients showed far fewer complications than is described in the literature. In particular, we could not retrace the robot-induced often mentioned soft tissue injuries and restrictions in mobility.

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Histotroph, secretions from luminal (LE), superficial glandular (sGE) and glandular (GE) epithelia and molecules selectively transported into the uterine lumen, are essential for peri-implantation ovine conceptus development and maternal recognition of pregnancy. Among them, several components of histotroph including nutrients, cell matrix proteins and growth factors may activate mTOR (mammalian target of rapamycin; also known as FRAP1) to stimulate hypertrophy, hyperplasia, and/or migration of conceptus trophectoderm cells, as well as expression of IFNT for pregnancy recognition and critical proteins for conceptus development. Therefore, studies were conducted to examine effects of select nutrients (arginine, leucine, glutamine and glucose), IGF2 and SPP1 on mTOR signal transduction pathways and determine their biological effects on proliferation, migration and/or attachment of ovine trophectoderm (oTr) cells and conceptuses (embryo and it extra-embryonic membranes). The first study defined the expression of IGF2, RPS6K, phosphorylated AKT, RPS6K, P38 and ERK1/2 MAPK by the uterus and conceptus during the periimplantation period. In addition, effects of IGF2 on the PI3K signaling pathway were evaluated using oTr cells isolated from Day 15 conceptuses. IGF2 was most abundant in compact stroma of endometrial caruncles and also present in all cells of the conceptus, but particularly abundant in the endoderm and yolk sac. Phosphorylated AKT1, RPS6K, P38 and ERK1/2 proteins were abundant in nuclei of endometrial LE and conceptus trophectoderm. IGF2 activated multiple cell signaling pathways including PDK/AKT/mTOR/RPS6K and MAPKs that are critical to survival, growth and migration of the ovine trophoblast cells. The second study demonstrated the multifunctional effects of secreted phosphoprotein 1 (SPP1) on oTr cells including cell signaling transduction, migration, and adhesion. Novel results of this study indicated that SPP1 binds ?v?3 and ?5?1 integrins to activate PI3K/mTOR/RPS6K, MAPK as well as crosstalk between mTOR and MAPK pathways that are essential for expansion and elongation of conceptuses and attachment of trophectoderm to uterine LE during implantation. The third study identified effects of arginine (Arg), leucine (Leu), glutamine (Gln) and glucose on oTr cells. Arg, Leu and glucose, but not Gln, activated PI3KAKT1 and mTOR-RPS6K-RPS6 signaling pathways. Arg, Leu and glucose increased abundance of p-RPS6K in nuclei and p-RPS6 in cytoplasm of oTr cells. In addition, results of this study demonstrated that Arg and Leu are remarkably stimulatory to cell proliferation and migration. The fourth study determined effects of Arg on signal transduction pathways and oTr cell proliferation, as well as inhibition of oTr cell proliferation by L-NAME (an inhibitor of NOS) or Nor-NOHA (an inhibitor of arginase) on oTr cells. Arg increased p-mTOR, RPS6K and 4EBP1 protein and also increased protein synthesis and reduced protein degradation in oTr cells. Both NO and polyamines enhanced cell proliferation in a dose-dependent manner. The effects of Arg were partially inhibited by both L-NAME and Nor-NOHA. These results indicate that Arg enhances production of polyamines and NO and activates the mTOR-FRAP1-RPS6K-RPS6 signaling pathway to stimulate proliferation of oTr. The fifth study identified differential effects of Arg, Leu, Gln and glucose on gene expression and protein translation in explants cultures of ovine conceptuses. Expression of mRNAs was not affected by treatments with the select nutrients; however, Arg, Leu, Gln and glucose increased abundance of total and phosphorylated forms of mTOR, RPS6K, 4E-BP1 and RPS6. Arg, Leu, Gln and glucose also increased the amounts of NOS and ODC1, but only Arg stimulated a significant increase in abundance of IFNT. Collectively, these studies indicated that IGF2, SPP1 and select nutrients activate mTOR cell-signaling pathways that converge on AKT1 and that are likely critical to mechanism(s) responsible for survival, elongation an development of conceptuses. A more complete understanding of this mechanism will be important to development of strategies to reduce early embryonic losses in ruminants and and in other species including humans.

The peri-implantation period in mammals is critical with respect to survival of the conceptus and establishment of pregnancy. During this period of pregnancy, reciprocal communication between ovary, conceptus, and endometrium is required for successful implantation and placentation. Therefore, studies were conducted to indentify and characterize novel endometrial genes important for implantation and conceptus development in the ovine uterus. The first and second studies defined the uterine expression of seven members of the cathepsin (CTS) family of lysosomal proteases, and a secreted inhibitor of CTSL called cystatin C (CST3) during the peri-implantation period. In addition, regulation of CTS and CST3 by progesterone (P4) and interferon tau (IFNT) was evaluated. CTSL was the most abundant CTS in the ovine ovine uterus and was also coordinately expressed with CST3 in the endometrial epithelia and conceptus trophectoderm. CTSL and CST3 were found to be novel P4-induced and IFNT-stimulated genes in the luminal epithelial cells of the ovine endometrium. The third study identified radical S-adenosyl methionine domain containing 2 (RSAD2) and interferon-induced with helicase C domain 1 (IFIH1) in the ovine uterus. Results of this study indicated that IFNT induces RSAD2 and IFIH1 in a P4-independent manner in the stroma, immune cells, and glands of the ovine endometrium. These two genes are proposed to have biological roles in the establishment of uterine receptivity to the conceptus during implantation. The fourth study characterized endometrial expression of stanniocalcins (STC) during pregnancy. STC1 appeared in the endometrial glands on Day 18 of pregnancy, increased from Days 18 to 80, and remained abundant through Day 120 of gestation. In addition, this study demonstrated that STC1 is induced by P4 and increased by placental hormones, such as placental lactogen (CSH1) and growth hormone (GH), in the ovine endometrial glands. Collectively, these studies identified genes that are expected to be critical to unraveling the mechanism(s) of reciprocal fetal-maternal interactions required for successful implantation and pregnancy. A more complete understanding of these genes will be important for developing therapeutic strategies to prevent, treat and/or diagnose infertility in domestic animals and humans, because they are biomarkers of P4 and/or IFN effects.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed January 5, 2010). PDF text: xxiv, 292 p. : ill. (some col.) ; 11 Mb. UMI publication number: AAT 3365710. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

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