In-chip microstructures and photonic devices fabricated by nonlinear laser lithography deep inside silicon

Silicon is an excellent material for microelectronics and integrated photonics 1-3, with untapped potential for mid-infrared optics 4 . Despite broad recognition of the importance of the third dimension 5,6, current lithography methods do not allow the fabrication of photonic devices and functional microelements directly inside silicon chips. Even relatively simple curved geometries cannot be realized with techniques like reactive ion etching. Embedded optical elements 7, electronic devices and better electronic-photonic integration are lacking 8 . Here, we demonstrate laser-based fabrication of complex 3D structures deep inside silicon using 1-μm-sized dots and rod-like structures of adjustable length as basic building blocks. The laser-modified Si has an optical index different to that in unmodified parts, enabling the creation of numerous photonic devices. Optionally, these parts can be chemically etched to produce desired 3D shapes. We exemplify a plethora of subsurface - that is, 'in-chip' - microstructures for microfluidic cooling of chips, vias, micro-electro-mechanical systems, photovoltaic applications and photonic devices that match or surpass corresponding state-of-the-art device performances. © 2017 The Author(s)

Central nervous system infections and diagnostic brain biopsy: Two case reports

Cerebral biopsy is an invasive technique with limited, specific indications in view of the potential risk of complications. Brain biopsy, aside from the direct sampling of a suspected neoplasm, is often diagnostic in cases of granulomatous angiitis, some forms of encephalitis, subacute spongioform encephalopathy, and a number of other rare diseases. Two cases who had a central nervous system infection and had undergone diagnostic brain biopsy in our clinic will be discussed by reviewing the literature. Copyright © 2005 by Türkiye Klinikleri

Nonrelated living-donor kidney transplantation: Medical and ethical aspects

Several patients with end-stage renal disease went to Bombay for renal transplantation from nonrelated living donors and then returned to Turkey for posttransplantation follow-up. The aims of this study are to evaluate the long-term results of renal transplantation from nonrelated living donors in Turkish patients with end-stage renal disease and to discuss the ethical and social aspects of nonrelated kidney donation. One hundred and twenty-seven patients (89 males, 38 females; mean age 38.1, range 17-63 years) were investigated retrospectively. None of the patients went to Bombay on our advice. All transplantations were performed between 1991 and 1995. The mean follow-up period after transplantation was 34.2 (range 1-68) months. Graft survival rates were 85, 83, and 57% after 3 months and 1 and 5 years, respectively. Patient survival rates were 94, 93, and 92% after 3 months and 1 and 5 years, respectively. Seven patients died within the first 3 months after the transplantation. Surgical problems, infections, acute rejection, ciclosporin nephrotoxicity, and hepatic problems were common complications. We conclude that medical and surgical complications occur frequently in paid kidney transplantation, but most of these complications can be prevented by adequate preoperative management, and precautionary measures should be taken to prevent commercialization of renal transplantation before the spread of emotionally related living kidney donation