Strong photo-absorption by a single quantum wire in waveguide-transmission spectroscopy

We measured the absorption spectrum of a single T-shaped, 14x6 nm lateral-sized quantum wire embedded in an optical waveguide using waveguide-transmission spectroscopy at 5 K. In spite of its small volume, the one-dimensional-exciton ground state shows a large absorption coefficient of 80 /cm, or a 98 % absorption probability for a single pass of the 500-um-long waveguide.Comment: 4 pages, 3 figure

Room-temperature excitonic absorption in quantum wires

We measured absorption spectra of T-shaped quantum wires at room temperature using waveguide-transmission spectroscopy. Strong and narrow room-temperature one-dimensional-exciton absorption peak was observed, which shows peak modal absorption coefficient of 160 cm$^{-1}$ per 20 wires with $\Gamma$-factor of $4.3\times10^{-3}$, width of 7.2 meV, and strong polarization anisotropy.Comment: 3pages, 3figure, 1tabl

Imaging of emission patterns in a T-shaped quantum wire laser

Spatially and spectrally resolved microscopic images of spontaneous and stimulated emissions are imaged at the mirror facets of a GaAs T-shaped quantum wire laser with high uniformity. Laser emission from the one-dimensional ground state reveals a circular image located at the core of a T-shaped optical waveguide but significantly smaller in area than the low power spontaneous emission from the same waveguide. These images unambiguously allow assignment of all spontaneous and laser emissions to the wire ground state and respective intersecting wells in the structure.Comment: 4 pages, 3 figure

Double Smiley Face Rod Method

We report a case of double-level lumbar spondylolysis at L4 and L5 that was successfully treated with the double “smiley face” rod method. A healthy 29-year-old man who presented with a 6-year history of chronic low back pain was referred to us for surgical treatment. Plain radiographs and computed tomography of the lumbar spine revealed bilateral pars defects at L4 and L5 without slip or scoliosis. The patient underwent direct repair of the pars defects using the double smiley face rod method at L4 and L5. There were no intraoperative or postoperative complications, and the patient had improved clinically by 1 year after surgery. The low back pain was completely disappeared and visual analog scale was 0. He restarted tennis again as the recreational level. While several techniques for direct repair of lumbar spondylolysis have been described, this is the first report of the double smiley face rod method being used to repair the consecutive double-level lumbar spondylolysis

Pancreatectomy in patients with LC

Background : Several reports have shown a high mortality rate in patients with liver cirrhosis (LC) who undergo pancreaticoduodenectomy, however, there are few reports on its long-term prognosis. Methods : Twelve patients with LC who had undergone pancreatic resection were enrolled. To compare clinicopathological variables, 159 non-LC patients who had undergone resection for pancreatic cancer were enrolled. Results : Pancreaticoduodenectomy (PD) was performed in 5 LC patients and distal pancreatectomy (DP) was performed in 7 LC patients. Patients in the LC group had more co-morbidities, lower platelet counts and higher Fib4 index than the non-LC group. The postoperative complication rate was higher in the LC group (83.3% vs 47.8%). While the postoperative hospital stay and 30-day mortality rate were not different, the 90-day mortality rate was higher in the LC group (25.0% vs 2.5% ; p < 0.01). Comparison by operative procedure showed no significant differences of postoperative outcomes in DP cases. However, in PD cases, postoperative complications were more frequent (100% vs 42.3%) and 90-day mortality was higher (40.0% vs 2.9% ; p < 0.01) in the LC group. Conclusions : PD resulted in higher postoperative morbidity and mortality rates in patients with LC compared with non-LC patients. DP could be tolerated in the LC patients

Comparison of the Fixation Strengths of Screws between the Traditional Trajectory and the Single and Double Endplate Penetrating Screw Trajectories Using Osteoporotic Vertebral Body Models Based on the Finite Element Method

Study Design This is a finite element (FE) study. Purpose To compare the fixation strength of traditional trajectory (TT) and single and double endplate penetrating screw trajectories (SEPST/DEPST) to the osteoporotic vertebral body model based on the FE method. Overview of Literature SEPST/DEPST have been developed to enhance the fixation strength in patients with diffuse idiopathic hyperostosis (DISH). This technique was also applied to patients with osteoporosis. However, determining the superiority of SEPST/DEPST is difficult because of the heterogeneous patient backgrounds. Methods Twenty vertebrae (T12 and L1) from 10 patients with osteoporosis (two males and eight females; mean age, 74.7 years) were obtained to create the 10 FE models. First, a single screw was placed with TT and SEPST/DEPST, and the fixation strength was compared by axial pullout strength (POS) and multidirectional loading tests. Second, two screws were placed on the bilateral pedicles with TT and SEPST/DEPST, and the fixation force of the vertebrae in the constructs in flexion, extension, lateral flexion, and axial rotation was examined. Results SEPST and DEPST had 140% and 171% higher POS values than TT, respectively, and the DEPST result was statistically significant (p=0.007). The multidirectional fixation strength was significantly higher in DEPST and SEPST than in TT in the cranial, caudal, and medial directions (p<0.05) but not in the lateral direction (p=0.05). The vertebral fracture strength at the lower instrumented vertebra of the DEPST tended to be higher than that of TT. The vertebral motion angles in SEPST and DEPST were significantly smaller in lateral bending (p=0.02) and tended to be smaller in flexion and extension than in TT (p=0.13). Conclusions This study may provide useful information for spine surgeons in deciding whether to choose the SEPS or DEPS technique for augmenting fixation in osteoporotic vertebral fracture surgery