published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Spermatozoa experience a series of physiological alternation upon traveling from the testis to the epididymis in order to acquire motility and capacity necessary to recognize and to fuse with an oocyte. Further maturation and modification of the spermatozoa occur along the journey in the female reproductive tract in a process known as capacitation. p53 protein is a well-known transcription factor involved in guarding of genome integrity by triggering cell cycle arrest and cell death upon DNA damage. p53-binding protein 1 (53BP-1) binds to p53 and enhances p53-mediated transcriptional activity. It has been reported that human spermatozoa produce 53BP-1 for DNA repair in response to oxidative stress. 53BP-1 is expressed in pre-implantation embryos. The current study aimed to identify the expression and subcellular location of 53BP-1 proteins in mouse spermatozoa by immunofluorescence staining. Increased expression of 53BP-1 proteins was found in the swim-up and capacitated mouse spermatozoa. The immunoreactivity was localized to the sperm head and midpiece, suggesting possible roles of 53BP-1 in sperm function. It was also found that mouse oocytes and 1-cell embryo also expressed 53BP-1. The potential function of 53BP-1 in early embryo development was also investigated using 53BP-1 antibody neutralized sperm in in-vitro fertilization. There was no significant difference between the development rate of embryos fertilized with spermatozoa transduced with anti-53BP-1 antibody and those that transduced with the control goat IgG. Further studies are needed to investigate the role of sperm 53BP-1 at later stage of embryo development and implantation. / published_or_final_version / Obstetrics and Gynaecology / Master / Master of Medical Sciences

published_or_final_version / abstract / toc / Chemistry / Master / Master of Philosophy

"Mémoire présenté à la Faculté des études supérieures en vue de l'obtention du grade de maître en droit. Option : droit des affaires"

Many semiconductor devices, such as heterostructure lasers and silicon bipolar transistors, require large concentrations of free carriers in the conduction and/or valence band of an active region. Under these conditions the band gap of the material is reduced by the many-body interactions of the carrier gas. The band gap narrowing results from a lowering of the conduction and raising of the valence band edge energies and is evaluated for a range of carrier concentrations. (10(^17) - 10(^22) cm_^-3)) in p-type Si and P- and n-type GaAs, Ga(_0.47) In(_0.53) As and Ga(_0.28) In(_0.72) As(_0.6) P(_0.4) at T = OK. A plasmon-pole approximation for the carrier gas dielectric function is used in the calculations. For all these materials, the largest energy shift occurs in the band containing the free carriers. For comparison the band edge shifts in all four materials are evaluated at finite temperature (300 K). The band gap narrowing at finite and zero temperatures differ notably only for low carrier concentrations (p < 5 x 10(^19) cm (^-3) in p-type Si) where the thermal excitation of the carriers reduces their screening effect so producing smaller band gap reduction. High hole concentrations also lead to increased optical losses in semi-conductor lasers due to intervalence band absorption (IVBA) transitions. These losses, which are considered to be partially responsible for the temperature dependence of threshold current densities in some semiconductor lasers, are evaluated in bulk laser materials using a pseudopotential band structure model. The temperature dependencies of the IVBA coefficients in GaAs, Ga(_0.47) In(_0.53) As and Ga(_0.28) In(_0.72) As(_0.6) P(_0.4) are shown to be either small or the coefficients themselves are negligible. Intervalence band absorption is also calculated for a 100/200 A GaAs/Ga(_0.7) al(_0.3) As quantum well laser structure for which the electronic band structure is determined using a variational k^-p approach. The wavelength dependence of the IVBA coefficients differs notably from corresponding results derived using simpler effective mass and pseudopotential models. In particular the k.p model gives significant contributions to the total loss, from certain 'forbidden' transitions.

University, Diss., 2006--Frankfurt (Main). / Erscheinungsjahr an der Haupttitelstelle: 2005.

Thesis (Ph. D.)--Cornell University, 1989. / Vita. Includes bibliographical references.

Zugl.: Marburg, Univ., Diss., 2007

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 5 uppsatser.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Cu2+; ATPase; CPx; CopB. Includes bibliographical references (p. 36-42).