Laser patterning of large-scale perovskite single-crystal-based arrays for single-mode laser displays

Lead halide perovskites have attracted considerable attention as potential candidates for high-performance nano/microlasers,owing to their outstanding optical properties.However,the further development of perovskite microlaser arrays(especially based on polycrystalline thin films)produced by the conventional processing techniques is hindered by the chemical instability and surface roughness of the perovskite structures.Herein,we demonstrate a laser patterning of large-scale,highly crystalline perovskite single-crystal films to fabricate reproducible perovskite single-crystal-based microlaser arrays.Perovskite thin films were directly ablated by femtosecond-laser in multiple low-power cycles at a minimum machining line width of approximately 300 nm to realize high-precision,chemically clean,and repeatable fabrication of microdisk arrays.The surface impurities generated during the process can be washed away to avoid external optical loss due to the robustness of the single-crystal film.Moreover,the high-quality,large-sized perovskite single-crystal films can significantly improve the quality of microcavities,thereby realizing a perovskite microdisk laser with narrow linewidth(0.09 nm)and low threshold(5.1µJ/cm2).Benefiting from the novel laser patterning method and the large-sized perovskite single-crystal films,a high power and high color purity laser display with single-mode microlasers as pixels was successfully fabricated.Thus,this study may offer a potential platform for mass-scale and reproducible fabrication of microlaser arrays,and further facilitate the development of highly integrated applications based on perovskite materials.

First proof-of-principle experiment with the post-accelerated isotope separator on-line beam at BRIF:measurement of the angular distribution of ^(23)Na+^(40)Ca elastic scattering

The reaction dynamics of exotic nuclei near the drip line is one of the main research topics of current interest.Elastic scattering is a useful probe for investigating the size and surface diffuseness of exotic nuclei.The development of rare isotope accelerators offers opportunities for such studies.To date,many relevant measurements have been performed at accelerators using the projectile fragmentation technique,while the measurements at accelerators using isotope separator on-line(ISOL)systems are still quite scarce.In this work,we present the first proof-of-principle experiment with a post-accelerated ISOL beam at the Beijing Radioactive Ion Beam Facility(BRIF)by measuring the angular distribution of elastic scattering for the stable nucleus^(23)Na from the doubly magic nucleus^(40)Ca at energies above the Coulomb barrier.The angular distribution measured by a silicon strip detector array in a scattering chamber using the ISOL beam at BRIF is in good agreement with that measured by the high-precision Q3 D magnetic spectrograph using the nonISOL beam at nearly the same energy.This work provides useful background for making BRIF a powerful tool for the investigation of the reaction dynamics of exotic nuclei.

Isolation and characterization of glacier VMY22, a novel lytic cold-active bacteriophage of Bacillus cereus

As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.

Shexiang Tongxin Dropping Pill combined with thrombus aspiration improves myocardial perfusion after PCI in patients with STEMI: the clinical research

Objective:To study the effect of Shexiang Tongxin Dropping Pill combined with thrombus aspiration on improving myocardial perfusion after PCI in patients with STEMI.Methods:A total of 104 patients with STEMI who received emergency PCI combined with thrombus aspiration in our hospital between May 2013 and October 2015 were selected as the research subjects and randomly divided into two groups: observation group received perioperative antiplatelet combined with Shexiang Tongxin Dropping Pill therapy, and the control group received perioperative antiplatelet therapy alone. Before treatment and 3 days after treatment, serum myocardial injury indexes, endothelial injury indexes and RAS system indexes were determined;4 weeks after treatment, serum ventricular remodeling indexes were determined. Results:3 d after treatment, serum CK, CK-MB, cTnI, cTnT, ET-1, vWF, PRA, AngII and ALD levels of both groups were significantly lower than those before treatment while NO level was significantly higher than that before treatment;serum CK, CK-MB, cTnI, cTnT, ET-1, vWF, PRA, AngII and ALD levels of observation group 3 d after treatment were significantly lower than those of control group while NO level was significantly higher than that of control group;4 weeks after treatment, serum PICP, ICTP, PIIINP, HSP47 and GDF-15 levels of observation group were significantly lower than those of control group.Conclusion: Shexiang Tongxin Dropping Pill application during perioperative period of PCI combined with thrombus aspiration can reduce myocardial cell damage and endothelial function injury as well as inhibit RAS system activation and ventricular remodeling.

Discrete modulational instability and bright localized spin wave modes in easy-axis weak ferromagnetic spin chains involving the next-nearest-neighbor coupling

We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor couplings.With a linear stability analysis, we calculate the growth rates of the modulational instability, and plot the instability regions.When the strength of the next-nearest-neighbor coupling is large enough, two new asymmetric modulational instability regions appear near the boundary of the first Brillouin zone.Furthermore, analytical forms of the bright nonlinear localized modes are constructed by means of a quasi-discreteness approach.The influence of the next-nearest-neighbor coupling on the Brillouin zone center mode and boundary mode are discussed.In particular, we discover a reversal phenomenon of the propagation direction of the Brillouin zone boundary mode.

Changes in plaque stability, cell apoptosis and coagulation indexes after patients with unstable angina pectoris accept adjuvant salvianolate therapy

Objective:To investigate the effect of adjuvant salvianolate therapy on plaque stability, cell apoptosis and coagulation indexes in patients with unstable angina pectoris.Methods: 92 patients with unstable angina pectoris treated in our hospital between May 2011 and August 2015 were collected, and after the treatment process and auxiliary examination results were retrospectively analyzed, they were divided into the control group (n=45) who accepted conventional treatment and the observation group (n=47) who accepted adjuvant salvianolate treatment. Before and after treatment, diasonograph was used to evaluate the plaque stability parameters of two groups of patients;ELISA was used to detect apoptosis-related molecule levels;immunoturbidimetry was used to detect blood coagulation indexes.Results: Before treatment, differences in plaque stability parameters, cell apoptosis molecules and coagulation indexes were not statistically significant between two groups of patients (P>0.05). After treatment, the plaque stability parameters plaque thickness, enhanced intensity, rise time and time to peak of observation group were significantly lower than those of control group (P<0.05);serum sFas, sFasL, fibrinogen (Fib), platelet (PLT), and D-Dimer (D-D) levels of observation group were significantly lower than those of control group while Bcl-2, prothrombin time (PT) and activated partial thromboplastin time (APTT) levels were significantly higher than those of control group (P<0.05).Conclusions: Adjuvant salvianolate treatment can increase the plaque stability, also inhibit myocardial cell apoptosis and improve the coagulation function in patients with unstable angina pectoris.

Highly exposed NiFeO_(x) nanoclusters supported on boron doped carbon nanotubes for electrocatalytic oxygen evolution reaction

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction(OER) is crucial for the overall water splitting. Herein, we prepared a highly exposed NiFeO_(x) ultra-small nanoclusters supported on boron-doped carbon nonotubes catalyst, which achieves a 10 mA/cm^(2) anodic current density at a low overpotential of 213 mV and the Tafel slope of 52 mV/dec in 1.0 mol/L KOH, superior to the pristine NiFeO_(x)-CNTs and other state-of-the-art OER catalysts in alkaline media. A combination study(XPS, sXAS and XAFS) verifies that the local atomic structure of Ni and Fe atoms in the nanoclusters are similar to NiO and Fe_(2)O_(3), respectively, and the B atoms which are doped into the crystal lattice of CNTs leads to the optimization of Ni 3d egorbitals. Furthermore, in-situ X-ray absorption spectroscopies reveal that the high valence state of Ni atoms are served as the real active sites. This work highlights that the precise control of highly exposed multicomponent nanocluster catalysts paves a new way for designing highly efficient catalysts at the atomic scale.

S-Nitrosylation-mediated coupling of DJ-1 with PTEN induces PI3K/AKT/mTOR pathway-dependent keloid formation

Background:Keloids are aberrant dermal wound healing characterized by invasive growth,extracellular matrix deposition,cytokine overexpression and easy recurrence.Many factors have been implicated as pathological causes of keloids,particularly hyperactive inflammation,tension alignment and genetic predisposition.S-Nitrosylation(SNO),a unique form of protein modification,is associated with the local inflammatory response but its function in excessive fibrosis and keloid formation remains unknown.We aimed to discover the association between protein SNO and keloid formation.Methods:Normal and keloid fibroblasts were isolated from collected normal skin and keloid tissues.The obtained fibroblasts were cultured in DMEM supplemented with 10%fetal bovine serum and 1%penicillin/streptomycin.The effects of DJ-1 on cell proliferation,apoptosis,migration and invasion,and on the expression of proteins were assayed.TurboID-based proximity labelling and liquid chromatography-mass spectrometry were conducted to explore the potential targets of DJ-1.Biotin-switch assays and transnitrosylation reactions were used to detect protein SNO.Quantitative data were compared by two-tailed Student’s t test.Results:We found that DJ-1 served as an essential positive modulator to facilitate keloid cell proliferation,migration and invasion.A higher S-nitrosylated DJ-1(SNO-DJ-1)level was observed in keloids,and the effect of DJ-1 on keloids was dependent on SNO of the Cys106 residue of the DJ-1 protein.SNO-DJ-1 was found to increase the level of phosphatase and tensin homolog(PTEN)S-nitrosylated at its Cys136 residue via transnitrosylation in keloids,thus diminishing the phosphatase activity of PTEN and activating the PI3K/AKT/mTOR pathway.Furthermore,Cys106-mutant DJ-1 is refractory to SNO and abrogates DJ-1-PTEN coupling and the SNO of the PTEN protein,thus repressing the PI3K/AKT/mTOR pathway and alleviating keloid formation.Importantly,the biological effect of DJ-1 in keloids is dependent on the SNO-DJ-1/SNO-PTEN/PI3K/AKT/mTOR axis.Conclusions:For the first time,this study demonstrated the effect of transnitrosylation from DJ-1 to PTEN on promoting keloid formation via the PI3K/AKT/mTOR signaling pathway,suggesting that SNO of DJ-1 may be a novel therapeutic target for keloid treatment.

Melatonin influences the biological characteristics of keloid fibroblasts through the Erk and Smad signalling pathways

Background:Keloids are abnormal fibrous hyperplasias that are difficult to treat.Melatonin can be used to inhibit the development of certain fibrotic diseases but has never been used to treat keloids.We aimed to discover the effects and mechanisms of melatonin in keloid fibroblasts(KFs).Methods:Flow cytometry,CCK-8 assays,western blotting,wound-healing assays,transwell assays,collagen gel contraction assays and immunofluorescence assays were applied to demonstrate the effects and mechanisms of melatonin in fibroblasts derived from normal skin,hypertrophic scars and keloids.The therapeutic potential of the combination of melatonin and 5-fluorouracil(5-FU)was investigated in KFs.Results:Melatonin significantly promoted cell apoptosis and inhibited cell proliferation,migration and invasion,contractile capability and collagen production in KFs.Further mechanistic studies demonstrated that melatonin could inhibit the cAMP/PKA/Erk and Smad pathways through the membrane receptor MT2 to alter the biological characteristics of KFs.Moreover,the combination of melatonin and 5-FU remarkably promoted cell apoptosis and inhibited cell migration and invasion,contractile capability and collagen production in KFs.Furthermore,5-FU suppressed the phosphorylation of Akt,mTOR,Smad3 and Erk,and melatonin in combination with 5-FU markedly suppressed the activation of the Akt,Erk and Smad pathways.Conclusions:Collectively,melatonin may inhibit the Erk and Smad pathways through the mem-brane receptor MT2 to alter the cell functions of KFs,while combination with 5-FU could exert even more inhibitory effects in KFs through simultaneous suppression of multiple signalling pathways.

The development of MOFs-based nanomaterials in heterogeneous organocatalysis

Metal-organic framework(MOF) is a class of inorganic-organic hybrid material assembled periodically with metal ions and organic ligands. MOFs have always been the focuses in a variety of frontier fields owing to the advantageous properties, such as large BET surface areas, tunable porosity and easyfunctionalized surface structure. Among the various application areas, catalysis is one of the earliest application fields of MOFs-based materials and is one of the fastest-growing topics. In this review, the main roles of MOFs in heterogeneous organocatalysis have been systematically summarized, including used as support materials(or hosts), independent catalysts, and sacrificial templates. Moreover, the application prospects of MOFs in photocatalysis and electrocatalysis frontiers were also mentioned.Finally, the key issues that should be conquered in future were briefly sketched in the final parts of each item. We hope our perspectives could be beneficial for the readers to better understand these topics and issues, and could also provide a direction for the future exploration of some novel types of MOFs-based nanocatalysts with stable structures and functions for heterogeneous catalysis.

Toward the most versatile fluorophore: Direct functionalization of BODIPY dyes via regioselective C–H bond activation

Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic,and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. The increasing success of BODIPY dyes is closely associated with their excellent and tunable photophysical properties due to their rich functionalization chemistry.Recently, growing research efforts have been devoted to the direct functionalization of the BODIPY core,because it allows the facile installation of desired functional groups in a single atom economical step. The challenges of this direct C-H derivation come from the difficulties in finding suitable functionalization agents and proper control of the regioselectivity of the functionalization. The aim of this work is to provide an overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C–H functionalization of the BODIPY framework.

Two-dimensional Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite as a high-performance photocatalyst for decomposition of tetracycline

Construction of photocatalysts with a Schottky heterojunction could realize highly efficient and stable degradation of organic pollutes in the wastewater.In this work,a precipitation method was used to prepare Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite photocatalysts with the Schottky heterojunction for the decomposition of tetracycline(TC)antibiotics under visible light.As-prepared photocatalysts were characterized by various techniques such as X-ray diffraction analysis(XRD),High resolution transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).When the best Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite was applied for the degradation of TC under visible light,the degradation efficiency reached up to 97.6%only in 50 min.It is considered that superoxide radical(O_(2)^(→))and hole(h^(+))were the main reactive species for the TC degradation,and in the Schottky heterojunction,e^(-)-h^(+)pairs in the catalyst could be transferred and separated effectively,resulting in obviously enhanced photocatalytic efficiency and stability.

Growth regulation of luminescent gold nanoparticles directed from amphiphilic block copolymers:highly-controlled nanoassemblies toward tailored in-vivo transport

The understanding of amphiphilic block copolymers(ABC)in encapsulation and transport of inorganic nanomedicines is highly desired.Still,it remains limited due to the challenges in the fabrication of nanoassemblies(NAs)with highly-controlled shape and loading of nanoparticles.Herein,through growth regulation of luminescent gold nanoparticles(Au NPs)by different reductants with ABC pluronic F127 as a template,a straightforward strategy is reported for in-situ fabrication of three wellcontrolled gold NAs(Au NAs)that display tunable shapes from spherical to elongated nanostructures and controllable surface chemistry and loading of Au NPs with distinct emissions but identical individual Au NP size.The three Au NAs exhibit tailored invivo transport behaviours:those with spherical shape and more hydrophilic surface show longer blood retention with higher tumor-targeting efficiency(~25.3%injection dose/g)and excellent long-term near-infrared tumor imaging even after 96 h postinjection.These findings provide a useful guidance in designing specific nanostructures for future nanomedicine transport.

Temporal and spatial chaos in the Kerr-AdS black hole in an extended phase space

Based on the Melnikov method,we investigate chaotic behaviors in the extended thermodynamic phase space for a slowly rotating Kerr-AdS black hole under temporal and spatial perturbations.Our results show that the temporal perturbation coming from a thermal quench of the spinodal region in the phase diagram may cause temporal chaos only when the perturbation amplitude is above a critical value,which involves the angular momentum J.Under the spatial perturbation,however,it is found that spatial chaos always occurs,independent of the perturbation amplitude.

An Intrinsic Rigidity Theorem for Closed Minimal Hypersurfaces in S^5 with Constant Nonnegative Scalar Curvature

Let M^4 be a closed minimal hypersurface in S^5 with constant nonnegative scalar curvature. Denote by f_3 the sum of the cubes of all principal curvatures, by g the number of distinct principal curvatures. It is proved that if both f_3 and g are constant,then M^4 is isoparametric. Moreover, the authors give all possible values for squared length of the second fundamental form of M^4. This result provides another piece of supporting evidence to the Chern conjecture.