Semi-metallic bulk generated spin-orbit torques in disordered topological insulator

Spin-orbit torque (SOT) induced by the transfer of orbital angular momentum from a lattice to a spin system offers an efficient route for manipulating spin-based devices. Among various potential candidates, three-dimensional topological insulators (TIs) with inherently strong spin-orbit coupling promise to be a powerful source of SOTs. While the huge SOTs observed in ferromagnet (FM)/TI bilayers are generally claimed to be of topological surface states (TSS) nature, the contributions from the surface and bulk states in realistic systems are undistinguishable, rendering the underlying physics elusive. Here, we provide direct evidence that the bulk spin-Hall effect dominates the SOTs generated by disordered TIs. We show that sizable SOTs with clear bulk feature are generated by bismuth antimonides, in which the semi-metallic bulk state intermediately couples to the surface states. From our analysis based on a drift diffusion approach, the lower limit of spin Hall conductivity turns out to be $0.66 \times 10 ^{5} (\hbar/2e)$ $\Omega$$^{-1}$m$^{-1}$, which is comparable to the reported values against the general belief in TSS origin. Furthermore, the complementary results of SOT generation and Gilbert damping enhancement suggest an essential role of band bending near the FM/TI interface upon modifying the relative magnitude of the real and imaginary parts of spin mixing conductance. Together with the bulk spin Hall effect, our finding may alter the landscape of the field of spin-orbitronics in TI based systems and develop new applications such as SOT transistors

Epidemiological and clinical features of lung cancer patients from 1999 to 2009 in Tokushima Prefecture of Japan

Lung cancer is the leading cause of malignancy-related death worldwide. In the present study, we reviewed the epidemiologic and clinical features of lung cancer in Tokushima Prefecture, Japan. Between January 1999 and December 2009, 2,183 patients with lung cancer were enrolled in this study. One thousand five hundred ninety-one (73%) patients were male and 592 (27%) patients were female. Median age was 70 years, with a range of 15-93 years. Seventy-six percent of patients had smoking history. One thousand nine hundred five (87%) patients were non-small cell lung cancer and the predominant histological type was adenocarcinoma (51%). Among all 2,183 patients, 702 (32%) belonged to elderly population. Four hundred seventy-one (22%), 213 (10%), 24 (1%), 116 (5%), 238 (11%), 370 (17%) and 678 (31%) patients had stage IA, IB, IIA, IIB, IIIA, IIIB and IV lung cancer, respectively. In Tokushima University Hospital, 516 (29%), 191 (11%), 58 (3%), 755 (43%) and 216 (12%) patients were initially treated with chemotherapy, chemo-radiotherapy, thoracic radiotherapy, operation and best supportive care, respectively. The median time to progression (TTP) and the median survival time (MST) of patients treated with chemotherapy and chemo-radiotherapy were 3.5 months, 13.0 months and 7.0 months, 18.0 months, respectively. The median TTP and the MST of 33 elderly patients treated with chemotherapy were 3.3 months and 18.0 months, respectively, which were comparable with those of total population. These results indicated the benefit of chemotherapy in elderly patients with advanced lung cancer by proper selection

Complications Associated With Spine Surgery in Patients Aged 80 Years or Older: Japan Association of Spine Surgeons with Ambition (JASA) Multicenter Study

Study Design:Retrospective study of registry data.Objectives:Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions.Methods:A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury.Results:Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications.Conclusions:Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients

Risk Factors for Delirium After Spine Surgery in Extremely Elderly Patients Aged 80 Years or Older and Review of the Literature: Japan Association of Spine Surgeons with Ambition Multicenter Study

Study Design:Retrospective database analysis.Objective:Spine surgeries in elderly patients have increased in recent years due to aging of society and recent advances in surgical techniques, and postoperative complications have become more of a concern. Postoperative delirium is a common complication in elderly patients that impairs recovery and increases morbidity and mortality. The objective of the study was to analyze postoperative delirium associated with spine surgery in patients aged 80 years or older with cervical, thoracic, and lumbar lesions.Methods:A retrospective multicenter study was performed in 262 patients 80 years of age or older who underwent spine surgeries at 35 facilities. Postoperative complications, incidence of postoperative delirium, and hazard ratios of patient-specific and surgical risk factors were examined.Results:Postoperative complications occurred in 59 of the 262 spine surgeries (23%). Postoperative delirium was the most frequent complication, occurring in 15 of 262 patients (5.7%), and was significantly associated with hypertension, cerebrovascular disease, cervical lesion surgery, and greater estimated blood loss (P < .05). In multivariate logistic regression using perioperative factors, cervical lesion surgery (odds ratio = 4.27, P < .05) and estimated blood loss ≥300 mL (odds ratio = 4.52, P < .05) were significantly associated with postoperative delirium.Conclusions:Cervical lesion surgery and greater blood loss were perioperative risk factors for delirium in extremely elderly patients after spine surgery. Hypertension and cerebrovascular disease were significant risk factors for postoperative delirium, and careful management is required for patients with such risk factors