The anomalous behavior of coefficient of normal restitution in the oblique impact

The coefficient of normal restitution in an oblique impact is theoretically studied. Using a two-dimensional lattice models for an elastic disk and an elastic wall, we demonstrate that the coefficient of normal restitution can exceed one and has a peak against the incident angle in our simulation. Finally, we explain these phenomena based upon the phenomenological theory of elasticity.Comment: 4 pages, 4 figures, to be appeared in PR

GM1 ganglioside in Parkinson\u27s disease: Pilot study of effects on dopamine transporter binding.

OBJECTIVE: GM1 ganglioside has been suggested as a treatment for Parkinson\u27s disease (PD), potentially having symptomatic and disease modifying effects. The current pilot imaging study was performed to examine effects of GM1 on dopamine transporter binding, as a surrogate measure of disease progression, studied longitudinally. METHODS: Positron emission tomography (PET) imaging data were obtained from a subset of subjects enrolled in a delayed start clinical trial of GM1 in PD [1]: 15 Early-start (ES) subjects, 14 Delayed-start (DS) subjects, and 11 Comparison (standard-of-care) subjects. Treatment subjects were studied over a 2.5 year period while Comparison subjects were studied over 2 years. Dynamic PET scans were performed over 90 min following injection of [(11)C]methylphenidate. Regional values of binding potential (BPND) were analyzed for several striatal volumes of interest. RESULTS: Clinical results for this subset of subjects were similar to those previously reported for the larger study group. ES subjects showed early symptomatic improvement and slow symptom progression over the study period. DS and Comparison subjects were initially on the same symptom progression trajectory but diverged once DS subjects received GM1 treatment. Imaging results showed significant slowing of BPND loss in several striatal regions in GM1-treated subjects and in some cases, an increased BPND in some striatal regions was detected after GM1 use. INTERPRETATION: Results of this pilot imaging study provide additional data to suggest a potential disease modifying effect of GM1 on PD. These results need to be confirmed in a larger number of subjects

Gluteal-fold adipofascial perforator flap transposition for rectourethral fistula reconstruction

If a rectourinary fistula does not close spontaneously, it requires surgical closure. We present our experience of rectourethral fistula reconstruction using a gluteal-fold perforator flap, resulting in a successful outcome. The patient was a 64-year-old man with prostate cancer who underwent radical prostatectomy. However, he developed rectourinary fistula, which required surgical closure. A dissection was undertaken to divide the fistula tract, and the rectal and urethral defect were closed. A 12.0×3.0 cm gluteal-fold adipofascial perforator flap was harvested and placed in the space between the rectum and urethra. The viability of lap was favourable, without infection or necrosis. The patient could walk the next day, and was discharged 2 weeks later without fecaluria or liquid stool. We conclude that the gluteal-fold adipofascial perforator flap offers excellent functional advantages in rectourethral fistula reconstruction with minimal morbidity at the donor site

Transcatheter Arterial Embolization for Shock Caused by Intratumoral Hemorrhaging in Neurofibromatosis Type 1: A Report of Two Cases

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disorder characterized by café-au-lait spots and neurofibroma. Vascular NF-1 lesions are rare, but bleeding from such lesions can sometimes cause lethal complications because surgical hemostasis is difficult to achieve due to the fragile nature of the surrounding blood vessels and soft tissue. In recent years, some reports have suggested that transcatheter arterial embolization (TAE) is an effective treatment for vascular NF-1 lesions. We report the cases of 2 NF-1 patients who developed intratumoral hemorrhaging and were successfully treated with TAE

Cerebral [O-15] water clearance in humans determined by positron emission tomography .2. Vascular responses to vibrotactile stimulation

When used to measure blood flow, water leaves a residue in the vascular bed, which may contribute to the calculation of increased blood flow during functional activation of brain tissue. To assess the magnitude of this contribution with the two-compartment positron emission tomography (PET) method, we mapped the water clearance (K1) of the brain as an index of cerebral blood flow (CBF) and the apparent vascular distribution of nonextracted H215O (Vo). The latter map represented mainly the cerebral arterial and arteriolar volume. We also prepared subtraction maps (DeltaK1, DeltaVo) of the response to vibrotactile stimulation of the fingertips of the right hand of six normal volunteers. Using magnetic resonance (MR) images of all subjects, the data were rendered into Talairach's stereotaxic coordinates and the averaged subtraction images (activation minus baseline) merged with the corresponding averaged MRI image. The DeltaK1 map revealed the expected response in the primary sensory hand area; the DeltaVo response was located about 13 mm more anteriorly, close to the central fissure, most likely reflecting changes of the arteries feeding the primary sensory hand area. We conclude that cerebral perfusion and cerebrovascular responses to vibrotactile stimulation may occur in disparate locations that can be identified separately by using the two-compartment method