Broadband on-chip polarization mode splitters in lithium niobate integrated adiabatic couplers.

We report, to the best of our knowledge, the first broadband polarization mode splitter (PMS) based on the adiabatic light passage mechanism in the lithium niobate (LiNbO3) waveguide platform. A broad bandwidth of ~140 nm spanning telecom S, C, and L bands at polarization-extinction ratios (PER) of >20 dB and >18 dB for the TE and TM polarization modes, respectively, is found in a five-waveguide adiabatic coupler scheme whose structure is optimized by an adiabaticity engineering process in titanium-diffused LiNbO3 waveguides. When the five-waveguide PMS is integrated with a three-waveguide "shortcut to adiabaticity" structure, we realize a broadband, high splitting-ratio (ηc) mode splitter for spatial separation of TE- (H-) polarized pump (700-850 nm for ηc>99%), TM- (V-) polarized signal (1510-1630 nm for ηc>97%), and TE- (H-) polarized idler (1480-1650 nm for ηc>97%) modes. Such a unique integrated-optical device is of potential for facilitating the on-chip implementation of a pump-filtered, broadband tunable entangled quantum-state generator.

Proton magnetic resonance spectroscopy in Kennedy disease.

The purpose of this study was to investigate the metabolic abnormalities in Kennedy disease (KD) patients using proton magnetic resonance spectroscopy. Five patients with KD showing typical phenotype were compared with eight age-matched, healthy control subjects. Relative metabolite concentrations for N-acetyl-aspartate (NAA), choline (Cho) and phosphocreatine (Cr) and lactate (Lac) were measured in the motor cortex and the brainstem area. In the motor cortex, NAA/Cr ratio was significantly reduced in KD patients (P=0.04). In the brainstem area, metabolic ratios including NAA/Cho, NAA/Cr and Cho/Cr failed to show significant difference between KD patients and normal controls. No pathologic Lac signal was noted in patients and controls. These findings corroborate a previous study indicating an involvement of the motor cortices in patients with KD.

Unusual subdural hematoma after SPA use.

We report a case of right tentorium subdural hematoma (SDH) in a 72-year-old man a few days after he visited a sanitas per aqua (SPA) facility. He had directed high-pressure water onto his head and neck. The patient was admitted to the emergency room during his 3rd day of severe throbbing and generalized headache. Cerebral computed tomography revealed a high-density SDH over the right tentorium. This is the first reported case of SPA-related SDH. Neurologists might consider the possibility that SPA use may be a factor in SDH or unexplained neurologic events in otherwise healthy persons.