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The Madden-Julian oscillation (MJO) has profound impacts on weather and climate phenomena, and thus changes in its activity have important implications under human-induced global climate change. Here, the time at which the MJO change signal emerges from natural variability under anthropogenic warming is investigated. Using simulations of the Community Earth System Model version 2 large ensemble forced by the shared socioeconomic pathways SSP370 scenario, an increase in ensemble mean MJO precipitation amplitude and a smaller increase in MJO circulation amplitude occur by the end of the 21st century, consistent with previous studies. Notably, the MJO precipitation amplitude change signal generally emerges more than a decade earlier than that of MJO wind amplitude. MJO amplitude changes also emerge earlier over the eastern Pacific than other parts of the tropics. Our findings provide valuable information on the potential changes of MJO variability with the aim of improving predictions of the MJO and its associated extreme events.

Self-assembled systems have recently attracted extensive attention because they can display a wide range of phase morphologies in nanocomposites, providing a new arena to explore novel phenomena. Among these morphologies, a bicontinuous structure is highly desirable based on its high interface-to-volume ratio and 3D interconnectivity. A bicontinuous nickel oxide (NiO) and tin dioxide (SnO2) heteroepitaxial nanocomposite is revealed here. By controlling their concentration, we fabricated tuneable self-assembled nanostructures from pillars to bicontinuous structures, as evidenced by TEM-energy-dispersive X-ray spectroscopy with a tortuous compositional distribution. The experimentally observed growth modes are consistent with predictions by first-principles calculations. Phase-field simulations are performed to understand 3D microstructure formation and extract key thermodynamic parameters for predicting microstructure morphologies in SnO2:NiO nanocomposites of other concentrations. Furthermore, we demonstrate significantly enhanced photovoltaic properties in a bicontinuous SnO2:NiO nanocomposite macroscopically and microscopically. This research shows a pathway to developing innovative solar cell and photodetector devices based on self-assembled oxides.

The novel amphiphilic acylated dextran-g-polyisobutylene (AcyDex-g-PIB) graft copolymers with different branch lengths (Mn,PIB, 2600–5800 g/mol) and grafting numbers (GN, 5–28 per 1000 Dex monosaccharide) were successfully synthesized via the nucleophilic substitution of the hydroxyl (―OH) side groups along AcyDex backbone by the living PIB-THF4+ chains prepared through cationic polymerization. The crystallization of AcyDex backbone in AcyDex-g-PIB graft copolymers was confined due to the presence of PIB branches and the morphology changed from short rod-like crystals to fragment-like crystals with increasing Mn,PIB and GN. The obvious microphase separation occurred due to the incompatibility between hard AcyDex backbone and soft PIB branches. AcyDex-g-PIB graft copolymers exhibit excellent biocompatibility towards HeLa cells and good hemocompatibility with red blood cells (RBCs), both of which increase with increasing GN. The increases of water contact angle and roughness on the surface of the graft copolymers with increasing Mn,PIB and GN manifest the anti-protein adsorption performance. The amphiphilic AcyDex-g-PIB graft copolymers could self-assemble in aqueous solution into nanospheres, which can be used as pH-sensitive drug carriers and can release 100% of the loaded drug within 72 h at pH=7.4. AcyDex-g-PIB graft copolymers bearing silver nanoparticles (Ag-NPs, 0.8 wt%–3.9 wt%, 4.5–9.5 nm) show good antibacterial properties. This kind of amphiphilic graft copolymer would have a promising prospect in biological and medical fields.

The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose (HPC) backbone and hydrophobic soft nonpolar polyisobutylene (PIB) branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the −OH groups along HPC backbone. The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/−OH molar ratio. The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgClO4 and silver nanoparticles (3.2±0.3 nm, 0.7 wt%–1.8 wt%) generated in situ from AgBr. The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches. The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches. The soft PIB segments in graft copolymers provided an unique surface via self-assembly for anti-protein adsorption against bovine serum albumin. A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.

Poly(styrene-b-isobutylene-b-styrene) triblock copolymer (SIBS), a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments, could be synthesized via living cationic copolymerization. A novel poly[(styrene-co-methylstyrene)-b-isobutylene-b-(styrene-co-methylstyrene)]-g-polytetrahydrofuran (M-SIBS-g-PTHF) block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS. A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol−1 to 4200 g·mol−1 were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran (THF) coinitiated by AgClO4. The introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene (PIB), polystyrene (PS) and PTHF. Moreover, the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months, leading to insolubility of the copolymers even in good solvents. The melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS-g5-PTHF-1.1k block graft copolymer increased remarkably up to 153 °C and 117.0 J·g−1 by 23 °C and 11.6 J·g−1 respectively after storage for long time. Storage modulus (G′) is higher than loss modulus (G″) of M-SIBS-g-PTHF block graft copolymer at temperatures ranging from 100 °C to 180 °C, which is much higher than those of the SIBS triblock copolymer. To the best of our knowledge, this is the first example of high performance M-SIBS-g-PTHF block graft copolymers containing segments of PIB, PS and PTHF with nanocrystallization-locked architecture.

To evaluate the diagnostic value of serum Brain-derived neurotrophic factor (BDNF) levels for discriminating PD with depression from without depression, and to investigate whether serum BDNF levels were associated with motor severity and gender in depressed PD patients. Demographic and clinical data were collected from 122 PD patients with depression, 137 without depression and 110 healthy controls. All participants’ serum BDNF concentrations were measured. Their motor abilities and activity were assessed by the Unified PD Rating Scale Part III (UPDRS III) score and the Hoehn and Yahr (H–Y) stage. Depression was scored using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Associations were analyzed with multivariate regression. The serum BDNF levels were lower in depressed PD patients compared to non-depressed PD patients and controls (p

The convergence-confinement method is widely used in conventional tunneling at a preliminary stage of the support design. A circular tunnel through the ground in an initially isotropic stress state and the behavior of ground-support interaction simplified utilizing a two-dimensional plane-strain are postulated. From a point of view of practical application, the direct algorithm process so-called the direct calculation method (DCM) is proposed in this paper to deal with solving the solution of stresses/displacements between the ground reaction curve (GRC) and the support confining curve (SCC) in the final equilibrium state by applying the simultaneous equations in the elastic region and using the numerical analysis known as the Newton recursion method for finding roots of the non-linear equations in the plastic region. This explicit procedure also can realize the analytical solution to an executable computation that can be stepwise estimated by using a simple calculation spreadsheet. The validity of the developed method for the analytical solution was examined by the finite element analysis (FEM) to investigate the influence of mechanical properties of the ground and the time-dependent effects of the shotcrete lining-support on the GRC, SCC and stress path at the intrados of the tunnel. The agreement of results between DCM and FEM was found to be excellent in the elastic and elastic-perfectly plastic media.

Neodymium complexes containing N-heterocyclic carbene (NHC) ligands, NdCl3[1,3-R2(NCH=)2C:]·THFx(Nd1: R = 2,6-iPr2C6H3, x = 0; Nd2: R = 2,6-Et2C6H3, x = 1; Nd3: R = 2,4,6-Me3C6H2, x = 1) were synthesized and employed as precatalysts for the coordination polymerization of conjugated dienes (butadiene and isoprene). In combination with triisobutylaluminium (TIBA), Nd1 promoted butadiene polymerization to produce extremely high cis-1,4 (up to 99.0%) polybutadienes with high molecular weight (Mw = 250–780 kg·mol−1). The Nd1/TIBA catalytic system also exhibited both high catalytic activity and cis-1,4 selectivity (up to 97.8%) for isoprene polymerization. The catalytic activity, molecular weight and molecular weight distribution of resulting polydienes were directly influenced by Al/Nd molar ratio, aging method, and polymerization temperature. Very interestingly, the high cis-1,4 selectivity of the catalyst towards butadiene and isoprene kept almost unchanged under different reaction conditions. The cis-1,4 polyisoprenes with high molecular weight (Mw = 210–530 kg·mol−1) and narrow molecular weight distribution (Mw/Mn = 1.9–2.7) as well as high cis-1,4 selectivity (~97%) could be synthesized by using the aged Nd1/TIBA catalytic system in the presence of isoprene (100 equivalent to Nd) at low Al/Nd molar ratios of 6–10. Polyisoprenes with low molecular weights (Mw = 12–76 kg·mol−1) and narrow molecular weight distributions (Mw/Mn = 1.7–2.6) were obtained by using Nd2 and Nd3 as precatalysts, indicating that the molecular weight of resulting polyisoprenes can be adjusted by changing the substitutes of ligand in Nd complex.

In order to quantify the poroelastic mechanical signals conduction and evaluate the biomechanical effectiveness of functional units (osteocyte processes, canaliculi and lacuna) in lacunar-canalicular system (LCS), a multiscale poroelastic finite element model was established by using the Comsol Multiphysics software. The poroelastic mechanical signals (pore pressure, fluid velocity, von-Mises stress, strain) were analyzed inside the osteon-osteocyte system. The effects of osteocyte (OCY)’s shape (ellipse and circle), long axis directions (horizontal and vertical) and mechanical properties (Elastic modulus and permeability) on its poroelastic responses were examined. It is found that the OCY processes is the best mechanosensor compared with the OCY body, lacunae and canaliculi. The mechanotransduction ability of the elliptic shaped OCY is stronger than that of circular shaped. The pore pressure and flow velocity around OCYs increase as the elastic modulus and permeability of OCY increase. The established model can be used for studying the mechanism of bone mechanotransduction at the multiscale level.

Organic solar cells are used in low-cost solar energy applications. Recently, organo-lead halide perovskite solar cells have attracted considerable interest. Low-temperature spin-coating is the simplest method to fabricate the low-cost solar cells; however, forming a continuous perovskite film by spin coating a precursor solution of lead iodide (PbI2) and methylammonium iodide (CH3NH3I) is challenging. This work investigated the characteristics of perovskite thin film, prepared using dimethylformamide (DMF) and dimethyl sulfoxide (DMSO)/γ-butyrolactone (GBL) solvents in the direct mixing of PbI2 and CH3NH3I. Perovskite films prepared using the DMSO/GBL solvent had greater crystallinity and compactness than those using the DMF solvent. Cell performance was improved by a perovskite absorber using the DMSO/GBL solvent to a power conversion efficiency of 8.87%, an open-circuit voltage of 0.82 V, a current density of 17.13 mA/cm2, and a fill factor of 63.01%.

The silicone rubber mold (SRM) has large applications for the pilot runs in the mold industry because it is capable of reducing the cost and time in a new product development phase. However, the cooling performance in the cooling stage is not acceptable after the injection molding due to low thermal conductivity of this material. To improve the cooling performance, five different fillers were added into the silicone rubber (SR) to develop SRM with better cooling performance in the cooling stage after injection molding. It was found that the alcohol used to remove the polyvinyl butyral resin cooling channels is less volatile, environmentally friendly, and less harmful to the operator compared with conventional method using acetone to remove the acrylonitrile butadiene styrene cooling channels. The cooling time of the molded wax pattern can be saved by 42.7%, 53.8%, 45.7%, 50.9%, and 16.7% for SRM with 60 wt.% Al, 80 wt.% Fe, 70 wt.% Cu, 25 wt.% graphite (G), and 20 wt.% carbon black powders compared with that for SRM without any fillers. The SR filled with 20 wt.% G powder seems to be the optimal method for producing an SRM with better cooling performance based on the heat transfer coefficient, production cost, and production yield of SRM.

The novel quaternized hydroxypropyl cellulose-g-poly(THF-co-epichlorohydrin) graft copolymers, HPC-g-QCP(THF-co-ECH), have been successfully synthesized to combine the properties from hydrophilic hard HPC biomacromolecular backbone and hydrophobic flexible polyether branches. Firstly, the P(THF-co-ECH) living chains were synthesized by cationic ring-opening copolymerization of THF with ECH. Secondly, P(THF-co-ECH) living chains were grafted onto HPC backbone by reaction with —OH groups along HPC to produce HPC-g-P(THF-co-ECH) graft copolymers. Thirdly, the mentioned graft copolymers were quaternized by reaction with ternary amine to generate functionalized HPC-g-QCP(THF-co-ECH). The HPC-g-QCP(THF-co-ECH) graft copolymers exhibited good antibacterial ability against S. aureus or E. coli bacteria. The ibuprofen (IBU)-loaded microparticles of HPC-g-(QC)P(THF-co-ECH) graft copolymers were prepared by electrospraying. The in vitro pH-responsive drug-release behavior of IBU reached up to 75% of drug-loaded at pH = 7.4. This quaternized graft copolymer was beneficial to solving the problems of a burst effect and fast release of HPC as drug carriers.

Consider the time-domain multiple cavity scattering problem, which arises in diverse scientific areas and has significant industrial and military applications. The multiple cavity embedded in an infinite ground plane, is filled with inhomogeneous media characterized by variable dielectric permittivities and magnetic permeabilities. Corresponding to the transverse electric or magnetic polarization, the scattering problem can be studied for the Helmholtz equation in frequency domain and wave equation in time-domain, respectively. A novel transparent boundary condition in time-domain is developed to reformulate the cavity scattering problem into an initial-boundary value problem in a bounded domain. The well-posedness and stability are established for the reduced problem. Moreover, a priori estimates for the electric field is obtained with a minimum requirement for the data by directly studying the wave equation., Comment: 29 pages,3 figures. arXiv admin note: text overlap with arXiv:1604.00944

The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4-tert-butoxystyrene (TBO), P(IB-co-ACS) and P(IB-co-TBO), could be successfully synthesized via cationic copolymerization with FeCl3-based initiating system. The kinetics of the cationic copolymerization process was in situ investigated by inserting a diamond probe into the reaction system by ATR-FTIR spectroscopy. The chemical structure and incorporation content of polar comonomers in the copolymers were characterized by GPC with RI/UV dual detectors and 1H-NMR spectroscopy. The corresponding functionalized random copolymers of IB with vinyl phenol P(IB-co-POH) carrying phenolic hydroxyl side groups could be further prepared via the complete hydrolysis of acetoxyl side groups in P(IB-co-ACS) or tert-butoxyl side groups in P(IB-co-TBO) copolymers. The functionalized P(IB-co-POH) copolymers became hydrophilic with water contact angle (WCA) of ca. 80° for the self-assembly in hot water, compared to the hydrophobic polyisobutylene with WCA of ca. 110°. The functionalized P(IB-co-POH) copolymers also displayed an excellent self-healing property due to the interaction of intermolecular hydrogen bonding and formation of three dimentional supramolecular networks from phenolic hydroxyl side groups. Furthermore, P(IB-co-POH) copolymers also provided a good matrix for the homogeneous dispersion for silica nanoparticles due to the formation of hydrogen bonding between copolymer chains and silica nanoparticles.

In this study, we evaluated the effect of functional disuse-induced bone remodeling on its mechanical properties, individually at periosteum and medullary endosteum regions of the cortical bone. Left middle tibiae were obtained from 5-month-old female Sprague-Dawley rats for the baseline control as well as hindlimb suspended (disuse) groups. Micro-nano-mechanical elastic moduli (at lateral region) was evaluated along axial (Z), circumferential (C) and radial (R) orientations using nanoindentation. Results indicated an anisotropic microstructure with axial orientation having the highest and radial orientation with the lowest moduli at periosteum and medullary endosteum for both baseline control as well as disuse groups. Between the groups: at periosteum, an insignificant difference was evaluated for each of the orientations (p 0.05) and at endosteum, a significant decrease of elastic moduli in the radial (p 0.0001), circumferential (p 0.001) and statistically insignificant difference in axial (p 0.05) orientation. For the moduli ratios between groups: at periosteum, only significant difference in the Z/R (p 0.05) anisotropy ratio, whereas at endosteum, a statistically significant difference in Z/C (p 0.001), and Z/R (p 0.001), as well as C/R (p 0.05) anisotropy ratios, was evaluated. The results suggested initial bone remodeling impaired bone micro-architecture predominantly at the medullary endosteum with possible alterations in the geometric orientations of collagen and mineral phases inside the bone. The findings could be significant for studying the mechanotransduction pathways involved in maintaining the bone micro-architecture and possibly have high clinical significance for drug use against impairment from functional disuse.

In this paper, a fluorescent and antibacterial nanocomposite film based on Zinc sulphide (ZnS) quantum dots, cellulose nanocrystals (CNCs) and polyvinyl alcohol (PVA) was successfully synthesized. CNCs were first decorated in situ with ZnS quantum dots, which were then introduced into a PVA matrix to prepare nanocomposite films with good fluorescent and antibacterial properties. The X-ray diffraction and scanning electron microscope analysis indicated that ZnS nanoparticles were well-dispersed and randomly coated on the CNCs with uniform particle size. The visible emission peak in the ZnS/CNCs nanocomposites was 473 nm with an excitation wavelength of 350 nm. The CNCs loaded with ZnS quantum dots exhibited bright blue fluorescence under the ultraviolet light. Additionally, CNCs/ZnS nanocomposite films also had good antibacterial properties (bacterial inhibition rate = 78.25%).

Sclerostin is an osteocyte-derived protein that has a potent inhibitory effect on osteoblast activity. The osteocyte apoptosis induced by various causes of osteonecrosis of the femoral head (ONFH) plays a key role in the promotion of femoral head collapse. But the effect of altering sclerostin level on the collapse of ONFH has not been studied. Our aim was to assess the role of sclerostin level in the collapse of ONFH. Between May 2016 and November 2016, 236 subjects were enrolled in the present study. The patients were classified according to the Association Research Circulation Osseous (ARCO) classification. The clinical bone histomorphology, the expression position, and level of sclerostin as well as the plasma sclerostin level were evaluated. The sclerostin level was significantly lower in the non-traumatic ONFH group than those in the healthy control group (P = 0.002). The sclerostin level was negatively associated with ARCO stages (r = − 0.239, P = 0.009) and significantly lower in the postcollapse group (P = 0.025). The reduced expression of sclerostin may play a key role in the collapse process of ONFH and be predictive of the disease progression of ONFH.