High-quality CMOS compatible n-type SiGe parabolic quantum wells for intersubband photonics at 2.5-5 THz

A parabolic potential that confines charge carriers along the growth direction of quantum wells semiconductor systems is characterized by a single resonance frequency, associated to intersubband transitions. Motivated by fascinating quantum optics applications leveraging on this property, we use the technologically relevant SiGe material system to design, grow, and characterize n-type doped parabolic quantum wells realized by continuously grading Ge-rich Si1-x Ge x alloys, deposited on silicon wafers. An extensive structural analysis highlights the capability of the ultra-high-vacuum chemical vapor deposition technique here used to precisely control the quadratic confining potential and the target doping profile. The absorption spectrum, measured by means of Fourier transform infrared spectroscopy, revealed a single peak with a full width at half maximum at low and room temperature of about 2 and 5 meV, respectively, associated to degenerate intersubband transitions. The energy of the absorption resonance scales with the inverse of the well width, covering the 2.5-5 THz spectral range, and is almost independent of temperature and doping, as predicted for a parabolic confining potential. On the basis of these results, we discuss the perspective observation of THz strong light-matter coupling in this silicon compatible material system, leveraging on intersubband transitions embedded in all-semiconductor microcavities

Radiation-associated sarcoma of the skull base after irradiation for pituitary adenoma

Secondary, radiation-induced neoplasms represent a significant long-term risk after radiation treatment, and radiation-induced sarcomas (RAS) have an especially poor prognosis. These have rarely been reported after irradiation for pituitary adenomas

ICAR: endoscopic skull‐base surgery

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A nuclear magnetic resonance spectrometer concept for hermetically sealed magic angle spinning investigations on highly toxic, radiotoxic, or air sensitive materials

A concept to integrate a commercial high-resolution, magic angle spinning nuclear magnetic resonance (MAS-NMR) probe capable of very rapid rotation rates (70 kHz) in a hermetically sealed enclosure for the study of highly radiotoxic materials has been developed and successfully demonstrated. The concept centres on a conventional wide bore (89 mm) solid-state NMR magnet operating with industry standard 54 mm diameter probes designed for narrow bore magnets. Rotor insertion and probe tuning take place within a hermetically enclosed glovebox, which extends into the bore of the magnet, in the space between the probe and the magnet shim system. Oxygen-17 MAS-NMR measurements demonstrate the possibility of obtaining high quality spectra from small sample masses (∼10 mg) of highly radiotoxic material and the need for high spinning speeds to improve the spectral resolution when working with actinides. The large paramagnetic susceptibility arising from actinide paramagnetism in (Th1−xUx)O2 solid solutions gives rise to extensive spinning sidebands and poor resolution at 15 kHz, which is dramatically improved at 55 kHz. The first 17O MAS-NMR measurements on NpO2+x samples spinning at 55 kHz are also reported. The glovebox approach developed here for radiotoxic materials can be easily adapted to work with other hazardous or even air sensitive materials

Pituitary surgery: experience from a large network in Central Switzerland

PRINCIPLES: During the past years our group built a care network for patients with pituitary tumours with referrals from the midlands and the central part of Switzerland, comprising about 1.6 million inhabitants. The purpose of this retrospective observational study with longitudinal data is to review the experience of pituitary surgery and the operative outcome within this Swiss-wide largest network. METHODS: A total of 182 patients operated at the Neurosurgical Department of the Kantonsspital Aarau 2005-2010 were included in this study. The follow-up was 3.6+/-1.6 years. RESULTS: The following lesions were found: non-functioning adenoma (n = 114; 63%); macroprolactinoma (n = 18; 10%); microprolactinoma (n = 11; 6%); acromegaly (n = 11; 6%), Cushing's disease (n = 7; 4%); Rathke's cleft cyst (RCC; n = 9; 5%); others (n = 12; 7%). Intraoperative MRI (iMRI) was used in 115 (63%) patients. Preoperatively, hypopituitarism was found in 105 (58%) patients. Postoperative recovery of defunct axes was detected in 48%. Visual field and visual acuity deficits due to optic pathway compression by tumour were detected in 48% and 41% of the patients, respectively. Postoperative recovery of visual function was seen in 89%. The increase of total resection rate by iMRI was statistically significant (p = 0.0007). Recurrent tumour growth was seen in 5 (3%) patients during follow-up. CONCLUSIONS: Transsphenoidal surgery is the primary treatment for most sellar lesions. The use of iMRI may lead to higher gross total resection rates. In Switzerland close cooperation between specialised centres is a very positive experience both to support operative case loads and to optimise patient follow-up

Optofluidic sensor system with Ge PIN photodetector for CMOS-compatible sensing

Vertical optofluidic biosensors based on refractive index sensing promise highest sensitivities at smallest area footprint. Nevertheless, when it comes to large-scale fabrication and application of such sensors, cheap and robust platforms for sample preparation and supply are needed—not to mention the expected ease of use in application. We present an optofluidic sensor system using a cyclic olefin copolymer microfluidic chip as carrier and feeding supply for a complementary metal–oxide–semiconductor compatibly fabricated Ge PIN photodetector. Whereas typically only passive components of a sensor are located within the microfluidic channel, here the active device is directly exposed to the fluid, enabling top-illumination. The capability for detecting different refractive indices was verified by different fluids with subsequent recording of the optical responsivity. All components excel in their capability to be transferred to large-scale fabrication and further integration of microfluidic and sensing systems. The photodetector itself is intended to serve as a platform for further sophisticated collinear sensing approaches