238 research outputs found

    Magnetic field induced enhancement of spin-order peak intensity in La(1.875)Ba(0.125)CuO(4)

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    We report on neutron-scattering results on the impact of a magnetic field on stripe order in the cuprate La1.875_{1.875}Ba0.125_{0.125}CuO4_4. It is found that a 7 T magnetic field applied along the {\it c} axis causes a small but finite enhancement of the spin-order peak intensity and has no observable effect on the peak width. Inelastic neutron-scattering measurements indicate that the low-energy magnetic excitations are not affected by the field, within experimental error. In particular, the small energy gap that was recently reported is still present at low temperature in the applied field. In addition, we find that the spin-correlation length along the antiferromagnetic stripes is greater than that perpendicular to them.Comment: 4 pages, 5 figure

    Ecophysiological responses of two poplar species to intraspecific and interspecific competition under different nitrogen levels

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    Aims Populus deltoides and P. euramericana are widely used in China as major forestry species. At present, little is known about their responses to nitrogen (N) deficiency when grown in monocultures or mixed plantations. The aim of this investigation was to analyze the growth, and morphological and physiological responses of P. deltoides and P. euramericana to different N levels under competition conditions. Methods We employed two Populus species (P. deltoides and P. euramericana) to discover how N deficiency affects plant traits under different competition types (P. deltoides x P. deltoides, intraspecific competition; P. euramericana x P. euramericana, intraspecific competition; P. deltoides x P. euramericana, interspecific competition). Potted seedlings were exposed to two N levels (normal N, N deficiency), and nitrogen- and competition-driven differences in growth, morphology and physiology were examined. Important Findings Under normal N conditions, interspecific competition significantly decreased the total root weight, root mass fraction (RMF), root-shoot ratio (R/S) and carbon/nitrogen ratio (C/N), and increased the leaf dry weight, leaf mass fraction and total leaf area of P. euramericana compared with intraspecific competition. The same conditions significantly affected the growth and morphological variables of P. deltoides, except for the dry weight of fine roots, R/S, specific leaf area, RMF, total nitrogen content and C/N compared with intraspecific competition. In addition, chlorophyll a (Chla), total chlorophyll (Tchl), carotenoid contents (Caro) and the carbon isotope composition (delta C-13) of P. deltoides were significantly lower in interspecific competition than in intraspecific competition, but no difference was detected in P. euramericana. The effects of N deficiency on P. deltoides under intraspecific competition were stronger than under interspecific competition. In contrast, the effects of N deficiency on P. euramericana between intraspecific and interspecific competition were not significantly different. These results suggest that under normal N condition, P. deltoides is expected to gain an advantage in monocultures rather than in mixtures with P. euramericana. Under N deficiency, the growth performance of P. euramericana was more stable than that of P. deltoides under both cultivation modes.Peer reviewe

    Nucleotide Sequences within the U5 Region of the Viral RNA Genome Are the Major Determinants for an Human Immunodeficiency Virus Type 1 to Maintain a Primer Binding Site Complementary to tRNAHis

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    AbstractThe initiation of reverse transcription of the human immunodeficiency virus type 1 (HIV-1) genome requires cellular tRNALys,3as a primer and occurs at a site in the viral RNA genome, designated as the primer binding site (PBS), which is complementary to the 3′-terminal 18 nucleotides of tRNALys,3. We previously described an HIV-1 virus [designated as HXB2(His-AC)], which contained a sequence within the U5 region complementary to the anticodon region of tRNAHisin addition to a PBS complementary to the 3′-terminal 18 nucleotides of the tRNAHis. That virus maintained a PBS complementary to tRNAHisafter extendedin vitroculture (Wakefieldet al., J. Virol.70, 966–975, 1996). In the present study, we report that subcloning a 200-base-pair DNA fragment encompassing the U5 and PBS regions from an integrated provirus of HXB2(His-AC) back into the wild-type genome (pHXB2) resulted in an infectious virus, designated as HXB2(His-AC-gac), which again stably maintained a PBS complementary to tRNAHis. DNA sequence analysis of the 200-base-pair region revealed only three nucleotide changes from HXB2(His-AC): a T-to-G change at nucleotide 174, a G-to-A change at nucleotide 181, and a T-to-C change at nucleotide 200. The new mutant virus replicated in CD4+Sup T1 cells similarly to the wild-type virus. Comparison of the nucleotide sequence of nucleocapsid gene of the wild-type and HXB2 (His-AC-gac) virus revealed no differences. Although we found numerous mutations in the reverse transcriptase gene in proviral clones derived from HXB2 (His-AC-gac), no common mutations were found among the 13 clones examined. Comparison of the virion-associated tRNAs of HXB2(His-AC-gac) with those of the wild type revealed that both viruses incorporated a similar subset of cellular tRNAs, with tRNALys,3being the predominant tRNA found within virions. There was no selective enrichment for tRNAHiswithin virions of HXB2(His-AC-gac) virus which selectively use tRNAHisto initiate reverse transcription. The results of these studies suggest that the U5 and PBS regions in the viral RNA genome are important determinants for HXB2(His-AC) viruses in the selective use of tRNAHisto initiate reverse transcription

    The Effect-enhancing and Toxicity-reducing Action of the Extract of Herba Scutellariae Barbatae for Chemotherapy in Hepatoma H22 Tumor-bearing Mice

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    ObjectiveTo investigate the effect-enchancing and toxicity-reducing action of the extract of Ban Zhi Lian (Herba Scutellariae Barbatae, EHSB) for chemotherapy in hepatoma H22 tumor-bearing mice.MethodsThe tumor-bearing mice were divided into 6 groups randomly: a model group, a high dose EHSB group, a low dose EHSB group, a 5-fluorouracil (5-FU) group, a 5-FU+high dose EHSB group and a 5-FU+low dose EHSB group, and with a normal group set as the controls. All the groups were treated for 10 days. The life prolongation rate, toxic reactions of chemotherapy, WBC count, the body weight, tumor weight, thymus index and spleen index, and phagocytic function of intra-abdominal macrophages were investigated in the H22 tumor-bearing mice.ResultsThe increase of the body weight in both the 5-FU+EHSB groups was significantly higher than that in the 5-FU group, with the toxic reactions such as anorexia, abdominal distension and emaciation significantly alleviated. Growth of the tumor was significantly inhibited in the high dose EHSB group, the 5-FU group, the 5-FU+high dose EHSB group, and the 5-FU+low dose EHSB group. The survival time in the 5-FU+high dose EHSB group and the 5-FU+low dose EHSB group was significantly prolonged as compared with that of the 5-FU group. The life prolongation rate was 98.72% in the 5-FU+high dose EHSB group and 52.11% in the 5-FU+low dose EHSB group. Growth of the transplanted tumor was significantly inhibited in the high dose EHSB group, the 5-FU group, the 5-FU+high dose EHSB group, the 5-FU+low dose EHSB group. The tumor inhibition rate in the high dose EHSB group, the 5-FU group, the 5-FU+high dose EHSB group and the 5-FU+low dose EHSB group was 36.98%, 42.26%, 65.28% and 52.45%, respectively. 5-FU combined with a high-dose EHSB could significantly enhance the tumor inhibition rate (P<0.05). The thymus index and the spleen index significantly increased in the high dose EHSB group, and atrophy of the immunological organs induced by chemotherapy was improved in the 5-FU+high dose EHSB group and in the 5-FU+low dose EHSB group. The WBC count decreased significantly in the 5-FU group, but increased in both the 5-FU+EHSB groups. The phagocytic function of intra-abdominal macrophages was increased in both the 5-FU+EHSB groups, with the phagocytic rate and the phagocytic index increased by 78.55% and 81.63% in the 5-FU+high dose EHSB group and by 43.97% and 44.90% in the 5-FU+low dose EHSB group.ConclusionsEHSB can significantly enhance the tumor inhibition rate of 5-FU, reduce the toxic effects, prolong the survival time, and improve immune function in the H22 tumor-bearing mice

    Biologically inspired deadbeat control of robotic leg prostheses

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    Recent advances in robotics technology provide great support for robotic leg prostheses to realize full biomechanical functionalities of the contralateral leg. In order to reproduce the biomechanical behaviors of the contralateral leg, this article addresses biologically inspired deadbeat control of robotic leg prostheses under different terrain conditions including level ground, stairs ascent, and descent. The proposed control method is based on the ground reactive force of the contralateral leg during walking. The trajectories of center-of-mass are encoded by the corresponding polynomial splines. Then, the control of the robotic leg prosthesis is designed by replicating the motion of the user's contralateral leg. Compared to most existing results, our approach does not require any preknowledge of the exact physical parameters. Finally, experiments are conducted to show that the prosthesis can help the user walk smoothly under various terrain conditions

    Performance of AC-LGAD strip sensor designed for the DarkSHINE experiment

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    AC-coupled Low Gain Avalanche Detector (AC-LGAD) is a new precise detector technology developed in recent years. Based on the standard Low Gain Avalanche Detector (LGAD) technology, AC-LGAD sensors can provide excellent timing performance and spatial resolution. This paper presents the design and performance of several prototype AC-LGAD strip sensors for the DarkSHINE tracking system, as well as the electrical characteristics and spatial resolution of the prototype sensors from two batches of wafers with different n+n^+ dose.The range of spatial resolutions of 6.5μm\mathrm{\mu m} ∼\sim 8.2μm\mathrm{\mu m} and 8.8μm\mathrm{\mu m} ∼\sim 12.3μm\mathrm{\mu m} are achieved by the AC-LGAD sensors with 100μm\mu m pitch size.Comment: 10 pages, 12 figure

    Clinical Effects of Shenqi Fuzheng Injection in the Neoadjuvant Chemotherapy for Local Advanced Breast Cancer and the Effects on T-lymphocyte Subsets

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    ObjectiveTo evaluate clinical effects of Shenqi Fuzheng Injection in the neoadjuvant chemotherapy for local advanced breast cancer and the effects on T-lymphocyte subsets.MethodsDuring the period from 2000 to 2005, 126 patients with local advanced breast cancer were treated with the neoadjuvant chemotherapy. They were randomly divided into the following two groups: a control group of 61 cases treated by chemotherapy alone and a study group of 65 cases treated by chemotherapy plus Shenqi Fuzheng Injection. All the cases of both groups were given the CEF (CTX 500 mg/m2, d1, 8; EPI 40 mg/m2, d1, 8; and 5-Fu 500 mg/m2, d1,8) regimen. The clinical effects, the effects on T-lymphocyte subgroup and NK cells, and the toxic side effects were observed.ResultsAll the patients completed two cycles of the chemotherapy, and the efficacy and the toxic side effects were evaluated. For the primary tumor in the breast, the total effective rate was 69.2% (45/65) in the study group and 49.2% (30/61) in the control group with a statistically significant difference in the intergroup comparison (χ 2=5.251, P=0.022, < 0.05). There was no progression of the disease in both the groups, and there were no grade IV toxic side effects in the two groups. The major toxic responses were myelosuppression and gastrointestinal reaction, which were milder in the study group than the control group, and with a shorter recovery course in the former than the latter. Besides, an obvious rise of the T-lymphocyte subgroup and NK cells was found in the study group after the neoadjuvant chemotherapy, with a very significant difference from the controls (P < 0.01).ConclusionShenqi Fuzheng Injection can improve and regulate immune function of the patients with local advanced breast cancer given the neoadjuvant chemotherapy, and therefore it can enhance the curative effect and reduce the side effect as well

    Design and implementation of an automatic nursing assessment system based on CDSS technology

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    BACKGROUND: Various quantitative and quality assessment tools are currently used in nursing to evaluate a patient's physiological, psychological, and socioeconomic status. The results play important roles in evaluating the efficiency of healthcare, improving the treatment plans, and lowing relevant clinical risks. However, the manual process of the assessment imposes a substantial burden and can lead to errors in digitalization. To fill these gaps, we proposed an automatic nursing assessment system based on clinical decision support system (CDSS). The framework underlying the CDSS included experts, evaluation criteria, and voting roles for selecting electronic assessment sheets over paper ones.METHODS: We developed the framework based on an expert voting flow to choose electronic assessment sheets. The CDSS was constructed based on a nursing process workflow model. A multilayer architecture with independent modules was used. The performance of the proposed system was evaluated by comparing the adverse events' incidence and the average time for regular daily assessment before and after the implementation.RESULTS: After implementation of the system, the adverse nursing events' incidence decreased significantly from 0.43 % to 0.37 % in the first year and further to 0.27 % in the second year (p-value: 0.04). Meanwhile, the median time for regular daily assessments further decreased from 63 s to 51 s.CONCLUSIONS: The automatic assessment system helps to reduce nurses' workload and the incidence of adverse nursing events.</p

    Ferulic Acid against Cyclophosphamide-Induced Heart Toxicity in Mice by Inhibiting NF- κ

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    The purpose of the present study was to elucidate the protective effects of ferulic acid (FA) against cyclophosphamide- (CTX-) induced changes in mice. Forty-eight male ICR mice were divided into four groups. Control group was intraperitoneally (i.p.) injected with 200 μL of phosphate buffer saline (PBS). Model group was intraperitoneally injected with a single dose of CTX (200 mg/kg). FA (50 mg/kg) and FA (100 mg/kg) groups were intraperitoneally injected with a single dose of CTX (200 mg/kg) followed by the intragastric treatment with FA (50, 100 mg/kg) for 7 consecutive days. After 12 d, the mice were sacrificed to analyze the hematological, biochemical, histological parameters and mechanism research. The results indicated that FA significantly decreased the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) in CTX-injected mice. In addition, FA effectively reduced the total numbers of white blood cells (WBCs), red blood cells, platelets, and hemoglobin content. FA also obviously attenuated the histological changes of the heart tissues caused by CTX. Moreover, Western blot demonstrated that FA inhibited the phosphorylations of NF-κB signaling pathway in CTX-stimulated cardiac tissues. In conclusion, FA might be considered as an effective agent in the amelioration of the heart toxicity resulting from CTX treatment

    Nitrogen Doped Carbon Nanosheets Encapsulated in situ Generated Sulfur Enable High Capacity and Superior Rate Cathode for Li-S Batteries

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    Lithium-sulfur batteries (LSBs), with large specific capacity (1,675 mAh g−1), are regarded as the most likely alternative to the traditional Lithium-ion batteries. However, the intrinsical insulation and dramatic volume change of sulfur, as well as serious shuttle effect of polysulfides hinder their practical implementation. Herein, we develop three-dimensional micron flowers assembled by nitrogen doped carbon (NC) nanosheets with sulfur encapsulated (S@NC-NSs) as a promising cathode for Li-S to overcome the forementioned obstacles. The in situ generated S layer adheres to the inner surface of the hollow and micro-porous NC shell with fruitful O/N containing groups endowing both efficient physical trapping and chemical anchoring of polysulfides. Meanwhile, such a novel carbon shell helps to bear dramatic volume change and provides a fast way for electron transfer during cycling. Consequently, the S@NC-NSs demonstrate a high capacity (1,238 mAh g−1 at 0.2 C; 1.0 C = 1,675 mA g−1), superior rate performance with a capacity retention of 57.8% when the current density increases 25 times from 0.2 to 5.0 C, as well as outstanding cycling performance with an ultralow capacity fading of only 0.064% after 200 cycles at a high current density of 5.0 C
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