Abstract
Topological superconductors (TSCs) are unconventional superconductors with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for ...quantum computation. Despite their importance in both fundamental research and applications, natural TSCs are very rare. Here, combining state of the art synchrotron and laser-based angle-resolved photoemission spectroscopy, we investigated a stoichiometric transition metal dichalcogenide (TMD), 2M-WS
2
with a superconducting transition temperature of 8.8 K (the highest among all TMDs in the natural form up to date) and observed distinctive topological surface states (TSSs). Furthermore, in the superconducting state, we found that the TSSs acquired a nodeless superconducting gap with similar magnitude as that of the bulk states. These discoveries not only evidence 2M-WS
2
as an intrinsic TSC without the need of sensitive composition tuning or sophisticated heterostructures fabrication, but also provide an ideal platform for device applications thanks to its van der Waals layered structure.
HIAF (High Intensity heavy ion Accelerator Facility), a new facility planned in China for heavy ion related researches, consists of two ion sources, a high intensity Heavy Ion Superconducting Linac ...(HISCL), a 45 Tm Accumulation and Booster Ring (ABR-45) and a multifunction storage ring system. The key features of HIAF are unprecedented high pulse beam intensity and versatile operation mode. The HIAF project aims to expand nuclear and related researches into presently unreachable region and give scientists possibilities to conduct cutting-edge researches in these fields. The general description of the facility is given in this article with a focus on the accelerator design.
The purpose of this study was to evaluate comparatively, in women undergoing caesarean section under spinal anesthesia, the effectiveness of hyperbaric bupivacaine combined with 3 different adjuvants ...(fentanyl, clonidine, and dexmedtomidine) on quality of blockade and maternal and neonatal repercussions.
84 patients undergoing elective surgeries under spinal anesthesia were randomized into 4 groups of 21 each, gB, gBF, gBC and gBD. Patients in groups gb, gBF, gBC and gBD were given bupivacaine alone, bupivacaine plus fentanyl (15.0 µg), bupivacaine plus fentanyl plus clonidine (75 µg), and bupivacaine plus dexmedetomidine (10 µg), respectively. Hemodynamic parameters evaluated were the onset and level of sensory block, perioperative analgesia, degree and recovery time of motor block, duration of analgesia, sedation, and maternal-foetal repercussions.
The onset of blockade was significantly faster in groups with adjuvants clonidine and dexmedetomidine compared with gB and gBF. Patients in Groups gB and gBF reported pain during the perioperative period. Duration of analgesia was significantly higher in Group gBD and was comparable to gBC and time to motor block recovery was significantly higher in Group gBD. Sedation was significant in Group gBD and gBC.
Addition of dexmedetomidine and clonidine as adjuvants to hyperbaric bupivacaine provided adequate anesthesia and postoperative analgesia compared to fentanyl adjuvant without causing any significant side effects.
Accumulating evidence has revealed that CD8+ T cell exhaustion (Tex) results in worse immunotherapy outcomes. However, the molecular functions and mechanisms of action of Tex in chemoresistance ...needed to be elucidated.
The populations of tumor-infiltrating CD8+ T cells (TILCD8Ts) in chemoresistant and chemosensitive groups of the GSE25066 dataset were calculated using CIBERSORT. Differentially expressed genes (DEGs) between TILCD8Ts and other immune cells were explored by integrating 16 immune cell datasets downloaded from the gene expression omnibus (GEO) database. Gene ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, univariate and multivariate Cox regression, and least absolute shrinkage and selection operator (LASSO) regression of TILCD8T-specific upregulated genes were used to construct a chemoresistant TILCD8T signature (cr-TILCD8TSig). Clinical prognostic data, genomic alterations, chemotherapy response, and immunotherapy response were compared between the different cr-TILCD8TSig subgroups in the GSE25066 and the cancer genome atlas breast cancer (TCGA-BRCA) cohorts.
A cr-TILCD8TSig with exhausted features was identified, consisting of seven genes (
, and
), which were identified from 104 TILCD8Ts-specific DEGs. Our results showed that compared to the cr-TILCD8TSig-low subgroup, the -high subgroup had a poorer distant relapse-free survival (DRFS) in the GSE25066 cohort and worse progression-free survival (PFS) in the TCGA-BRCA cohort. Univariate and multivariate Cox regression analyses also demonstrated that cr-TILCD8TSig was an independent prognostic factor in the two independent cohorts. Furthermore, cr-TILCD8TSig-low patients benefited more from chemotherapy and immunotherapy than cr-TILCD8TSig-high patients. Besides, we found cell transmembrane signal transduction and the ECM may provide the molecular basis for resistance to antitumor agents in the cr-TILCD8Sig-high subgroup. For genomic alterations, we revealed that mutations in PIK3CA, DMD, and APOB were more common in the cr-TILCD8Sig-high subgroup than in the cr-TILCD8Sig-low subgroup. A nomogram was finally constructed with good discrimination and calibration.
cr-TILCD8TSig is a useful tool to independently predict prognosis, chemotherapy response, and immunotherapy outcomes in patients with breast cancer.
A Ti-based in-situ beta (β) reinforced Ti61.75Zr33.25Cu5 bulk metallic glass composite (BMGC) with unique hybrid microstructure and enhanced mechanical properties were produced using laser Powder Bed ...Fusion (L-PBF) with elemental powder mixture. The Ti61.75Zr33.25Cu5 BMGC possessed high compressive strength of 1.9 GPa with total strain exceeding 13%, and its microstructure was composed of fine primary β dendrite and amorphous phase in the inter-dendrite. The undissolved Zr particle induced stress accumulation near the particle interface that affected the local shear behavior in the β dendrite and promoted slip bands multiplication. The inhomogeneous distribution of amorphous phase divided the BMGC into strong and weak domains and caused strain partition, leading to back stress strain hardening of the BMGC. It is also found that there exist dispersed ω particles and ω laths in the primary β dendrites during the L-PBF and the deformation process, respectively, leading to high strength but limited plasticity of the BMGC. Further improving the mechanical properties of the BMGC can be achieved by hindering the ω formation through alloying method. This work provides a guidance on the design of novel additively manufactured BMGCs with outstanding mechanical properties using low cost elemental powder mixture.
•LCF properties of a SC Ni-based superalloy with a central hole after different pre-rafting treatments were investigated.•The variation and spatial distribution of microstructural rafting near the ...central hole were captured by the FE-SEM approach and an image processing algorithm.•The role of the inhomogeneous rafting on LCF life and crack propagation behaviours were investigated.•An analytical model to bridge the inhomogeneous rafting and LCF life reduction was proposed based on the critical distance theory.
To revealing the role of unevenly microstructural rafting caused by stress gradient on the fatigue resistance of engineering parts made by single crystal (SC) Ni-based superalloys, a stress-control low cycle fatigue (LCF) experiments were performed at 980 °C with a 0.1 stress ratio of central-hole specimens that underwent different pre-rafting treatments. An image process algorithm and field emission scanning electron microscope (FE-SEM) were employed to given a quantitative description of the rafting field near the central hole experimentally. Within half radius of the central hole, the rafting state defined in the present work presents obvious gradient, which disappears with the deterioration of rafting conditions. The rafting morphology tends to be uniform that weakens the effect of inhomogeneous rafting microstructure on LCF resistance as the rafting state exceeds 0.6. The worsening of fatigue resistance is ascribed to the comprehensive degradation effect of rafting, even resulting in 90% reduction of fatigue life compared with the virgin state. Moreover, it was found that rafting changed the initial orientation of fatigue cracks, whereas the crack always propagated along the boundary of micro twins at the late life stage. Finally, an analytical model was proposed to given a quantitative linkage between the inhomogeneous rafting microstructure and the reduction of fatigue resistance.
•An atomistic representative cell of γ'/γ structure in Ni3Al superalloys is constructed to simulate the dislocation motions under different stress states.•An energy-based orientation criterion of ...rafting is proposed for complex stress states based on the MD results, which is validated by the experiments in the literature.•A thermodynamic rafting model based on the energy dissipation theory coupling with crystal plasticity constitutive relations was proposed to predict the variation law of microstructural features.
Directional coarsening behaviour, also known as rafting, largely determines the mechanical properties of Ni3Al superalloys. However, owing to a vague understanding of the micro-scale mechanisms of the superalloys, modelling their rafting behaviour is still challenging, especially under complex stress states. The present work aims to predict rafting behaviours under complex stress states through macro-scale thermodynamic approaches assisted by micro-scale molecular dynamics. First, an atomistic representative cell of the γ'/γ structure in the Ni3Al superalloy was constructed to simulate the dislocation motion and elastic and dislocation energy distribution in the γ matrix channels under different stress states at the initial rafting stage. Accordingly, an energy-based orientation criterion was proposed for the rafting behaviour under complex stress states. The criterion was then applied to a thermodynamic system of the γ'/γ structure to model the rafting behaviour on the basis of energy dissipation theory coupled with crystal plasticity constitutive relations. The new rafting model was verified by the experimental observations in the literature and was used to evaluate the effects of temperature and stress states on rafting. This research offers a basic understanding of the directional coarsening and provides a prediction tool for the direction and variation law of the rafting process.
K326 and HD represent major tobacco cultivars in China, which required large N fertiliser input but at different application rates. To understand primary components affecting tobacco N use ...physiology, we adopted these two varieties as valuable genetic material to assess their growth response to N nutrition. We established a hydroponic culture system to grow plants supplied with different N regimes. Plant biomass, N, ammonium, nitrate, arginine, GS and NR activity, N transfer and use efficiency as well as root uptake were examined. Our data revealed the preference of K326 and HD to utilise nitrate or ammonium nitrate but not ammonium alone, with 2 mm N supply probably sufficient and economical to achieve good biomass production at the vegetative stage. Moreover, both varieties were very sensitive to ammonium, perhaps due to lack of or abnormal signalling related to nitrate and/or arginine rather than impairment of N acquisition and initial assimilation; this was supported by measurements of the plant content of N, ammonium and activities of GS and NR. Notably, short-term
N root influx studies identified differential uptake kinetics of K326 and HD, with distinct affinities and transport rates for ammonium and nitrate. The data suggest that the growth adaptation of K326 or HD to higher or lower N may be ascribed to different competences for effective N uptake/translocation and assimilation. Thus, our work provides valuable information to prompt deeper investigation of the molecular basis controlling plant N use efficiency.
PDF
