4,921 research outputs found

    Broadband optical frequency comb generation with flexible frequency spacing and center wavelength

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    A comment on "Ab initio calculations of pressure-dependence of high-order elastic constants using finite deformations approach" by I. Mosyagin, A.V. Lugovskoy, O.M. Krasilnikov, Yu.Kh. Vekilov, S.I. Simak and I.A. Abrikosov

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    Recently, I. Mosyagin, A.V. Lugovskoy, O.M. Krasilnikov, Yu.Kh. Vekilov, S.I. Simak and I.A. Abrikosov in the paper: "Ab initio calculations of pressure-dependence of high-order elastic constants using finite deformations approach"[Computer Physics Communications 220 (2017) 2030] presented a description of a technique for ab initio calculations of the pressure dependence of second- and third-order elastic constants. Unfortunately, the work contains serious and fundamental flaws in the field of finite-deformation solid mechanics.Comment: 3 pages, 0 figure

    2-(2-{[2-(4-Pyridylcarbon­yl)hydrazinyl­idene]meth­yl}phen­oxy)acetic acid

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    In the title compound, C15H13N3O4, the pyridine and benzene rings are nearly perpendicular [dihedral angle = 84.24 (5)°]. In the crystal structure, classical O—H⋯N hydrogen bonding between the OH group of the carboxyl unit and a neighbouring pyridine ring N atom and N—H⋯O hydrogen bonding between the imine NH group and a neighbouring O atom of an acyl unit, together with complementary non-classical C—H⋯O hydrogen bonds between carboxyl O atoms and neighbouring CH groups, link the mol­ecules into a three-dimensional system

    Lithium-conductive LiNbO₃ coated high-voltage LiNi₀₅Co₀₂Mn₀₃O₂ cathode with enhanced rate and cyclability

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    LiNi_{0.5}Co_{0.2}Mn_{0.3}O_{2} (NCM523) cathode materials can operate at extremely high voltages and have exceptional energy density. However, their use is limited by inherent structure instability during charge/discharge and exceptionally oxidizing Ni^{4+} at the surface. Herein, we have developed a citrate-assisted deposition concept to achieve a uniform lithium-conductive LiNbO_{3} coating layer on the NCM523 surface that avoids self-nucleation of Nb-contained compounds in solution reaction. The electrode–electrolyte interface is therefore stabilized by physically blocking the detrimental parasitic reactions and Ni^{4+} dissolution whilst still maintaining high Li+ conductivity. Consequently, the modified NCM523 exhibits an encouraging Li-storage specific capacity of 207.4 mAh g^{−1} at 0.2C and 128.9 mAh g^{−1} at 10C over the range 3.0–4.5 V. Additionally, a 92% capacity retention was obtained after 100 cycles at 1C, much higher than that of the pristine NCM523 (73%). This surface engineering strategy can be extended to modify other Ni-rich cathode materials with durable electrochemical performances

    Ten-year changes in the prevalence of overweight, obesity and central obesity among the Chinese adults in urban Shanghai, 1998–2007 — comparison of two cross-sectional surveys

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    BACKGROUND: In China, obesity is expected to increase rapidly in both urban and rural areas. However, there have been no comprehensive reports on secular trends in obesity prevalence among Chinese adults in urban Shanghai, which is the largest city in southern China. METHODS: In 1998–2001 and again in 2007–2008, two independent population-based cross-sectional surveys were conducted in Shanghai to investigate the prevalence of metabolic disorders. These surveys obtained height, waist circumference (WC), and weight measurements for Chinese adults aged between 20 and 74 years who lived in urban communities. From the 1998–2001 survey, 4,894 participants (2,081 men and 2,813 women, mean age: 48.9 years) were recruited, and 4,395 participants (1,599 men and 2,796 women, mean age: 49.8 years) were recruited from the 2007–2008 survey. Using the World Health Organization criteria, overweight was defined as 25 kg/m(2) ≤ BMI < 30 kg/m(2) and obesity as BMI ≥ 30 kg/m(2). Central obesity was defined as WC ≥ 90 cm in men or ≥85 cm in women. The differences in prevalence of obesity, central obesity and overweight between the two surveys were tested using multivariable logistic regression analyses. RESULTS: Compared to the 1998–2001 survey, in the 2007–2008 survey the BMI distribution for men and the WC distribution for both genders is shifted significantly to the right along the x-axis (all p < 0.001). Over the ten years, the prevalence of combined overweight and obesity increased 24% (from 31.5% to 39.1%, p < 0.001) in men, but decreased 8% (from 27.3% to 25.0%; p < 0.01) in women. The prevalence of central obesity increased 40% in men (from 19.5% to 27.3%; p < 0.01), but the increase was not significant in women (15.0% to 17.1%; p = 0.051). In the total population, only central obesity showed a significant change between the populations in the two surveys, increasing 29% (from 17.3% to 22.4%; p < 0.001). CONCLUSIONS: Over this 10 year period, central obesity increased significantly in the Shanghai adult population. However, the prevalence of combined overweight and obesity was significantly increased in men but not in women

    Integrable semi-discretization for a modified Camassa-Holm equation with cubic nonlinearity

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    In the present paper, an integrable semi-discretization of the modified Camassa-Holm (mCH) equation with cubic nonlinearity is presented. The key points of the construction are based on the discrete Kadomtsev-Petviashvili (KP) equation and appropriate definition of discrete reciprocal transformations. First, we demonstrate that these bilinear equations and their determinant solutions can be derived from the discrete KP equation through Miwa transformation and some reductions. Then, by scrutinizing the reduction process, we obtain a set of semi-discrete bilinear equations and their general soliton solutions in the Gram-type determinant form. Finally, we obtain an integrable semi-discrete analog of the mCH equation by introducing dependent variables and discrete reciprocal transformation. It is also shown that the semi-discrete mCH equation converges to the continuous one in the continuum limit

    Intravenous Busulfan-Cyclophosphamide as a Preparative Regimen Before Allogeneic Hematopoietic Stem Cell Transplantation for Adult Patients with Acute Lymphoblastic Leukemia

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    The use of i.v. busulfan (BU) instead of the oral formulation can improve outcomes in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) by reducing toxicity and transplantation-related mortality (TRM). There are limited reports of i.v. BU used to treat patients with acute lymphoblastic leukemia (ALL). The present study was performed to evaluate the efficacy and toxicity of i.v. BU/cyclophosphamide (CY) conditioning in adult ALL. We retrospectively analyzed 42 consecutive patients who underwent allo-HSCT with BU/CY conditioning between January 2007 and October 2010 with an HLA-matched donor (sibling, n = 18; unrelated, n = 24). Thirty-three patients were in first complete remission (CR1), 2 were in second complete remission (CR2), and 7 were in a more advanced stage. Median patient age was 28 years (range, 17∼55 years). The median follow-up was 15 months (range, 1∼48 months). Overall, 13 patients died, for a 30-month overall survival of 56.5% ± 10.6% (65.7% ± 12.5% for patients in CR1 vs 25.4% ± 15.5% for those in CR2 or beyond; P < .001). Eleven patients experienced relapse between 2 and 26 months after allo-HSCT, with a 30-month relapse rate (RR) of 40% ± 10.9% (32.0% ± 12.7% for patients in CR1 vs 71.4% ± 17.1% for those in CR2 or beyond; P = .001). The incidence of grade II-IV acute graft-versus-host disease (GVHD) was 39.2% ± 8.8%, and that of grade III-IV acute GVHD was 7.4% ± 4.1%. The incidence of chronic GVHD was 63.9% ± 11.7%, and that of extensive chronic GVHD was 19.3% ± 7.9%. Only 2 cases of clinically diagnosed veno-occlusive disease (VOD) were documented (4.7%), and 1 of these patients died of severe VOD. Other BU/CY conditioning–associated toxicities were diffuse alveolar hemorrhage in 1 patient and hemorrhagic cystitis in 8 patients. Four patients died due to TRM, for a 30-month TRM of 9.7% ± 4.6%. This study demonstrates that i.v. BU/CY can be considered a feasible conditioning regimen for adult ALL, with low incidences of VOD and TRM
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