820 research outputs found

    Organic Molecules in Low-Mass Protostellar Hot Cores: Submillimeter Imaging of IRAS 16293-2422

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    Arcsecond-resolution spectral observations toward the protobinary system IRAS 16293-2422 at 344 and 354 GHz were conducted using the Submillimeter Array. Complex organic molecules such as CH3OH and HCOOCH3 were detected. Together with the rich organic inventory revealed, it clearly indicates the existence of two, rather than one, compact hot molecular cores (smaller than or equal to 400 AU in radius) associated with each of the protobinary components identified by their dust continuum emission in the inner star-forming core.Comment: 11 pages, 3 figures, to be published in ApJ

    Adjuvant treatment for patients with incidentally resected limited disease small cell lung cancer-a retrospective study.

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    Background With the exception of very early-stage small cell lung cancer (SCLC), surgery is not typically recommended for this disease; however, incidental resection still occurs. After incidental resection, adjuvant salvage therapy is widely offered, but the evidence supporting its use is limited. This study aimed to explore proper adjuvant therapy for these incidentally resected SCLC cases. Methods Patients incidentally diagnosed with SCLC after surgery at the Shanghai Pulmonary Hospital in China from January 2005 to December 2014 were included in this study. The primary outcome was overall survival. Patients were classified into different group according to the type of adjuvant therapy they received and stratified by their pathological lymph node status. Patients' survival was analyzed using a Kaplan-Meier analysis and Cox regression analysis. Results A total of 161 patients were included in this study. Overall 5-year survival rate was 36.5%. For pathological N0 (pN0) cases (n=70), multivariable analysis revealed that adjuvant chemotherapy (ad-chemo) was associated with reduced risk of death [hazard ratio (HR): 0.373; 95% confidence interval (CI): 0.141-0.985, P=0.047] compared to omission of adjuvant therapy. For pathological N1 or N2 (pN1/2) cases (n=91), taking no adjuvant therapy cases as a reference, the multivariable analysis showed that ad-chemo was not associated with a lower risk of death (HR: 0.869; 95% CI: 0.459-1.645, P=0.666), while adjuvant chemo-radiotherapy (ad-CRT) was associated with a lower risk of death (HR: 0.279; 95% CI: 0.102-0.761, P=0.013). Conclusions Patients who incidentally receive surgical resection and are diagnosed with limited disease SCLC after resection should be offered adjuvant therapy as a salvage treatment. For incidentally resected pN0 cases, ad-chemo should be considered and for pN1/2 cases, ad-CRT should be received

    New Family of Robust 2D Topological Insulators in van der Waals Heterostructures

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    We predict a new family of robust two-dimensional (2D) topological insulators in van der Waals heterostructures comprising graphene and chalcogenides BiTeX (X=Cl, Br and I). The layered structures of both constituent materials produce a naturally smooth interface that is conducive to proximity induced new topological states. First principles calculations reveal intrinsic topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be further enhanced up to 120 meV by compression. The strong spin-orbit coupling in BiTeX has a significant influence on the graphene Dirac states, resulting in the topologically nontrivial band structure, which is confirmed by calculated nontrivial Z2 index and an explicit demonstration of metallic edge states. Such heterostructures offer an unique Dirac transport system that combines the 2D Dirac states from graphene and 1D Dirac edge states from the topological insulator, and it offers new ideas for innovative device designs

    Several closed expressions for the Euler numbers

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