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C32H18F8O8N2Rh2, monoclinic, P21/n (no. 11), a = 9.28200(12) Å, b = 11.33638(13) Å, c = 16.0352(2) Å, β = 105.9326(14)° V = 1622.47 Å3, Z = 4, Rgt(F) = 0.0297, wRref(F2) = 0.0763, T = 150 K. [ABSTRACT FROM AUTHOR]

Background: The less volatile fraction of perfumes is susceptible to contamination by phthalate esters (PAEs), which are endocrine-disrupting chemicals encountered during the production, bottling, and transportation processes. There is a need to establish an innovative and rapid method for the determination of trace PAEs in commercial perfumes. Objective: Therefore, self-built spray-inlet microwave plasma torch (MPT) ionization coupled with quadrupole time-of-flight (QTOF) tandem MS (MS/MS) was developed for the direct analysis of PAEs in perfumes without sample pretreatment. Methods: Perfumes were sprayed directly onto the flame of the MPT by means of a sampling pump at a rate of 10 mL/min and the ions produced by the MPT were introduced into the QTOF-MS equipment with the MPT operating at 2450MHz and 40W at a flow rate of 800 ml/min of argon. Results: For the established method, excellent linearity was obtained with a correlation coefficient of 0.9799 for di-n-pentyl phthalate and of greater than 0.99 for the other substances tested. The LOD and LOQ obtained were in the ranges of 1.452-18.96 and 4.839-63.19 ng/g, respectively. The spiked recoveries of PAEs ranged from 100.1 to 105.2% with satisfactory intraday RSDs and interday RSDs ranging from 1.51 to 4.34% and 3.45 to 5.65%, respectively. PAEs in commercial perfumes were successfully detected by spray-inlet MPT-MS/MS with low concentrations ranging from 0.036 to 1.352 mg/g. Conclusions: The method is a promising tool for the on-site analysis of PAEs in cosmetic solutions requiring rapid qualitative and quantitative analysis. Highlights: The method was successfully applied to the analysis of the commercial perfume samples within 30 s, and displayed the merits of simplicity, sensitivity, environmental friendliness and ease of operation. [ABSTRACT FROM AUTHOR]

A novel double negative curvature terahertz fiber with elliptical tubes as cladding structure is designed and investigated. Six uniformly arranged elliptical hole tubes and six circular tubes are connected to each other as the cladding structure of the fiber. The confinement loss, bending loss, dispersion, and effective mode field area of the fiber are calculated in two different frequency regions. The simulation shows that the lowest confinement loss of 3.2 × 10−6 dB cm−1 can be achieved at 2.44 THz. The confinement loss is always in the order of 10−5–10−6 dB cm−1 in the frequency band of 2.22–2.5 THz. The waveguide dispersion of fiber remains between −0.18 and 0.05 ps/(THz × cm) in the frequency band of 2.04–2.4 THz. Moreover, the bending loss of 4.4 × 10−5 dB cm−1 can be obtained when the bending radius is 25 cm. The debut of this double negative curvature terahertz fiber, with combined advantages of ultralow confinement loss, low bending loss, low and flat dispersion and simple structure forebodes a new approach to completely release the potential of fiber in terahertz applications. [ABSTRACT FROM AUTHOR]

Countering the terahertz wave applications 'inefficient transmission' calls for rapid development in terahertz waveguides that could simultaneously minimize confinement loss, chromatic dispersion and maximize the fraction of power. Here, a new kind of symmetrical petal hollow core terahertz waveguide based on cyclic olefin homopolymer is proposed to achieve low confinement loss, low chromatic dispersion and a high fraction of power. In this designed waveguide, a symmetrical petal-shaped air hole is treated as the core and circular air holes arranged as sunflower-type are inserted in the cladding. The guiding characteristics of the designed waveguide are simulated and analyzed based on the finite element method with perfectly matched layer boundary condition. Based on the optimum structure parameters, it exhibits a minimum confinement loss of 0.0089 dB cm−1 at 2.58 THz and a < 0.07 dB cm−1 bandwidth spanning across 2.51–2.71 THz. Furthermore, in the same frequency region, the high core power fraction is above 93%, and the group velocity dispersion values are lower than 0.6 ps/THz/cm. [ABSTRACT FROM AUTHOR]

Improving the endurance performance for hafnia-based ferroelectric thin films and devices is of considerable significance from both scientific and technological perspectives. Here, we obtained robust ferroelectricity in Hf0.5Zr0.5O2 (HZO) thin films without the need of the confinement from top electrodes by systematically optimizing the conditions and parameters for the post-deposition annealing (PDA) process. Compared with the post-metallization annealing (PMA) process, PDA is found to markedly improve the ferroelectric endurance performance. In particular, wake-up-free ferroelectric HZO thin films with an exceptional endurance performance (∼3 × 1010 cycles) are obtained by PDA processing conducted under an oxygen atmosphere, which is attributed to the suppression of oxygen deficiency in the HZO thin films and the inhibition of interfacial reaction layer that inevitably forms during annealing treatment for PMA processing. Our work offers insight into improving ferroelectricity and endurance for hafnia-based ferroelectric materials and devices. [ABSTRACT FROM AUTHOR]

Four thienylene (C4H2S) bridged Mo2 dimers, [Mo2(DAniF)3]2(μ-OOCC4H2SCOO) (DAniF = N,N′-di(p-anisyl)formamidinate), [Mo2(DAniF)3]2(μ-N(H)SCC4H2SCN(H)S), [Mo2(DAniF)3]2(μ-OSCC4H2SCSO) and [Mo2(DAniF)3]2(μ-SSCC4H2SCSS), have been synthesized and studied in terms of electronic coupling. The subtle structural differences between these compounds vary largely the extent of electron delocalization; consequently, a systematic transition from Class II to Class III via Class II–III is achieved, which is probed using spectral parameters of intervalence charge transfer (IVCT) absorption (band energy, intensity and shape) for the mixed-valence complexes. Significantly, the species in Class II–III displays a low energy, half cut-off and solvent-dependent IVCT band, while a high energy, less asymmetrical IVCT band is observed for the complex in Class III. These results give fresh and detailed understanding of the system transition. [ABSTRACT FROM AUTHOR]

Assembling two quadruply bonded dimolybdenum units [Mo2(DAniF)3]+ (DAniF= N,N′-di( p-anisyl)formamidinate) with 1,4-naphthalenedicarboxylate and its thiolated derivatives produced three complexes [{Mo2(DAniF)3}2(μ-1,4-O2CC10H6CO2)], [{Mo2(DAniF)3}2(μ-1,4-OSCC10H6COS)], and [{Mo2(DAniF)3}2(μ-1,4-S2CC10H6CS2)]. In the X-ray structures, the naphthalene bridge deviates from the plane defined by the two Mo−Mo bond vectors with the torsion angle increasing as the chelating atoms of the bridging ligand vary from O to S. The mixed-valent species exhibit intervalence transition absorption bands with high energy and very low intensity. In comparison with the data for the phenylene analogues, the optically determined electronic coupling matrix elements ( Hab=258-345 cm−1) are lowered by a factor of two or more, and the electron-transfer rate constants ( ket≈1011 s−1) are reduced by about one order of magnitude. These results show that, when the electron-transporting ability of the bridge and electron-donating (electron-accepting) ability of the donor (acceptor) are both variable, the former plays a dominant role in controlling the intramolecular electron transfer. DFT calculations revealed that increasing the torsion angle enlarges the HOMO-LUMO energy gap by elevating the (bridging) ligand-based LUMO energy. Therefore, our experimental results and theoretical analyses verify the superexchange mechanism for electronic coupling and electron transfer. [ABSTRACT FROM AUTHOR]

RNA replication of positive-strand (+)RNA viruses requires the lipids present in intracellular membranes, the sites of which viral replicases associate with. However, the direct effects of membrane lipids on viral replicases are still poorly understood. Wuhan nodavirus (WhNV) protein A, which associates with mitochondrial membranes, is the sole replicase required for RNA replication. Here, we report that WhNV protein A binds to RNA1 in a cooperative manner. Moreover, mitochondrial membrane lipids (MMLs) stimulated the RNA binding activity and cooperativity of protein A, and such stimulations exhibited strong selectivity for distinct phospholipids. Interestingly, MMLs stimulated the RNA-binding cooperativity only at higher protein A concentrations. Further investigation showed that MMLs stimulate the RNA binding of protein A by promoting its self-interaction. Finally, manipulating MML metabolism affected the protein A-induced RNA1 recruitment in cells. Together, our findings reveal the direct effects of membrane lipids on the RNA binding activity of a nodaviral replicase. [ABSTRACT FROM AUTHOR]

Abstract: A 3D metal-organic framework {[Cd2(TZ)3(BDC)0.5]·5H2O} n (1·5nH2O) (HTZ=1H-tetrazole, H2BDC=1,4-benzenedicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The phase purity was confirmed by powder X-ray diffraction (PXRD), and the stability was identified by thermal gravimetric analysis (TG) and variable-temperature powder X-ray diffraction (VT-PXRD). The result of the single-crystal X-ray diffraction analysis indicates that 1 is a novel 3D microporous metal-organic framework constructed from Cd(II) metal centers and mixed linkers of TZ− anions and BDC2− anions. Photoluminescent measurement elucidates that 1 displays a strong and broad emission peak at 423nm, which suggests that 1 may be a potential purple-light material. [Copyright &y& Elsevier]

New fully integrated single-chip impulse ultra-wideband (UWB) transmitter front-ends, integrating tunable impulse or monocycle pulse generator with bi-phase shift keying (BPSK) modulator, has been developed using a standard low-cost 0.18-μm CMOS process. The monocycle pulse generator component produces 0.7–0.75 V peak-to-peak monocycle pulse with 140–350 ps tunable pulse duration. The impulse generator generates 0.95–1.05 V peak-to-peak Gaussian-type impulse signal with 100–300 ps tunable pulse duration. The BPSK modulator controls the pulse generator to generate positive or negative pulse signal depending on the “1” or “0” digital data information. The pulse signals produced by the developed transmitters are useful for various UWB applications, especially those requiring the capability of changing ranges and resolutions using only a single system. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1609–1614, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25250 [ABSTRACT FROM AUTHOR]

A single-chip broadband CMOS receiver front-end, integrating a low-noise amplifier (LNA), a correlator, and a template pulse generator, was investigated in nonsinusoidal time-domain environment for possible use as an impulse-type ultra-wideband (UWB) receiver front-end. Particularly, the CMOS LNA and the multiplier making up the core component of the correlator were designed, fabricated, and tested to verify operation in the UWB range. Time-domain results of the integrated CMOS receiver front-end demonstrate its workability as a receiver for nonsinusoidal UWB applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2590–2595, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24682 [ABSTRACT FROM AUTHOR]

A novel millimeter-wave cavity resonator, completely compatible with commercial CMOS fabrication techniques, has been designed and fabricated in a 0.25-μm CMOS process and tested. The resonator employs a capacitively loaded cavity topology effectively implemented using the CMOS multimetal-layer and via-hole structure. The CMOS capacitively loaded cavity resonator, including two coupling apertures and microstrip feed lines, occupies an area of 2 mm × 1.4 mm × 6.28 μm, which is much smaller than the cavity resonator designed without a capacitive load at the same resonant frequency. It resonates at 30 GHz with a corresponding insertion loss of 2 dB and unloaded quality factor of 22.2. The resonant-frequency reduction is approximately 50%, as compared to that without the capacitive load. The design and performance of a new CMOS coupling aperture, which is useful as a coupling mechanism and a vertical interconnect for highly dense millimeter-wave CMOS RF integrated circuits (RFICs) are also presented. The developed low-loss and compact CMOS cavity resonator can be used to realize various millimeter-wave on-chip passive components such as wideband bandpass filters and diplexers and is suitable for direct integration with other CMOS circuits on a single chip. It is attractive for CMOS RFIC design at millimeter-wave frequencies. [ABSTRACT FROM AUTHOR]

C30H24Cl4O10Rh2, monoclinic, P21/n (no. 14), a = 7.5270(4) Å, b = 12.3533(6) Å, c = 17.4904(8) Å, β = 91.780(4)°, V = 1625.52(14) Å3, Z = 2, Rgt(F) = 0.0458, wRref(F2) = 0.1285, T = 150(1) K. [ABSTRACT FROM AUTHOR]

A novel low-cost low-power fully integrated tunable transmit module composed of a tunable CMOS monocycle pulse generator and compact uniplanar antenna was designed, built, and tested for ultra-wideband (UWB) impulse systems. The CMOS tunable pulse generator integrates a tuning delay circuit, square-wave generator, impulse-forming circuit, and pulse-shaping circuit in a single chip using a standard low-cost 0.25-μm CMOS process. It can generate a monocycle pulse and Gaussian-type impulse (without the pulse-shaping circuitry) signals with tunable pulse duration. A compact uniplanar UWB antenna was also developed and integrated directly with the CMOS pulse generator chip to form the complete integrated tunable UWB transmit module. Measured results show that the CMOS tunable pulse generator can produce a 0.3-0.6-V peak-to-peak monocycle pulse with 140-350-ps tunable pulse duration and a 0.5-1.3-V peak-to-peak impulse signal with 100-300-ps tunable pulse-duration, and the uniplanar antenna has less than a 18-dB return loss and is suitable for transmitting/receiving UWB time-domain impulse signals covering the entire UWB bandwidth of 3.1-10.6 GHz. Good agreement between measured and calculated performance is also achieved. The UWB transmit module was experimentally characterized and its performance is verified. This UWB module finds applications in various time-domain UWB systems including wireless communications and radar. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) as a promising technology for large‐scale energy storage have received unprecedented attention. However, the cathodes in SIBs generally suffer from detrimental cathode‐electrolyte interfacial side reactions and structural degradation during cycling, which leads to severe capacity fade and voltage decay. Here, we have developed an ultra‐stable Na0.72Ni0.20Co0.21Mn0.55Mg0.036O2 (NCM‐CS‐GMg) cathode material in which a Mg‐free core is encapsulated by a shell with gradient distribution of Mg using coprecipitation method with Mg‐hysteretic cascade feedstock followed by calcination. From the interior to outer surface of the shell, as the content of electrochemically inactive Mg gradually increases, the Na+ deintercalation amount gradually decreases after charged. Benefiting from this surface gradient desodiation, the surface transition metal (TM) ion migration from TM layers to Na layers is effectively inhibited, thus suppressing the layered‐to‐rock‐salt phase transition and the resultant microcracks. Besides, the less formation of high‐valence TM ions on the surface contributes to a stable cathode‐electrolyte interface. The as‐prepared NCM‐CS‐GMg exhibits remarkable cycling life over 3000 cycles with a negligible voltage drop (0.127 mV per cycle). Our findings highlight an effective way to developing sustainable cathode materials without compromising on the initial specific capacity for SIBs. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) as a promising technology for large‐scale energy storage have received unprecedented attention. However, the cathodes in SIBs generally suffer from detrimental cathode‐electrolyte interfacial side reactions and structural degradation during cycling, which leads to severe capacity fade and voltage decay. Here, we have developed an ultra‐stable Na0.72Ni0.20Co0.21Mn0.55Mg0.036O2 (NCM‐CS‐GMg) cathode material in which a Mg‐free core is encapsulated by a shell with gradient distribution of Mg using coprecipitation method with Mg‐hysteretic cascade feedstock followed by calcination. From the interior to outer surface of the shell, as the content of electrochemically inactive Mg gradually increases, the Na+ deintercalation amount gradually decreases after charged. Benefiting from this surface gradient desodiation, the surface transition metal (TM) ion migration from TM layers to Na layers is effectively inhibited, thus suppressing the layered‐to‐rock‐salt phase transition and the resultant microcracks. Besides, the less formation of high‐valence TM ions on the surface contributes to a stable cathode‐electrolyte interface. The as‐prepared NCM‐CS‐GMg exhibits remarkable cycling life over 3000 cycles with a negligible voltage drop (0.127 mV per cycle). Our findings highlight an effective way to developing sustainable cathode materials without compromising on the initial specific capacity for SIBs. [ABSTRACT FROM AUTHOR]

A new compact, low-cost uniplanar impulse generator using coplanar waveguide structure has been designed, built, and tested. This uniplanar circuit consists of three functions: initial impulse generation, impulse amplification, and impulse compression, which are realized by a step-recovery diode and two-stage GaAs MESFET circuits, respectively. The impulse response has an amplitude of 2.3 V and a half-power pulse width of 115 pS. It has larger amplitude and narrower pulse width than the impulse generated by the SRD circuit alone. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 470–472, 2003 [ABSTRACT FROM AUTHOR]

This paper estimates the social welfare effect of China’s largest online ride-sharing platform. Under the plausible assumption that consumers would change from traditional transportation to online ride-sharing when the marginal benefit of saved time outgrows the additional cost, we calculate the distribution of implied wage rate of passengers. We then use the passenger wage rate to calculate the social welfare generated by the decrease in waiting time and the reduction of waiting uncertainty brought about by the ride-sharing platform. Our estimate suggests that the ride-sharing platform created a total of 130.5 billion Yuan of social welfare in the three years between 2016 and 2018, and the consumer surplus and producer surplus created by an average transaction are 5.4 Yuan and 2.5 Yuan, respectively. The robustness test finds that our results were insensitive to the assumed risk aversion coefficient in the model, the subsample number used for each city, and the inclusion of nonlinear terms in the model. Alternative hypotheses, such as learning effect, seem unable to explain our result. [ABSTRACT FROM AUTHOR]

This study introduces focused ion beam (FIB) processing for the first time to etch and thin β‐Ga2O3 microflakes, while exploring the effect of their thicknesses on the phototransistor performance. It is found that when the β‐Ga2O3 microflakes reach a certain thickness, the phototransistors switch from the depletion mode to the enhancement mode, exhibiting extremely low dark current without a gate voltage. The enhancement‐mode phototransistor prepared using this method demonstrates a photo‐dark current ratio as high as 2.3 × 105, a responsivity of 6.3 × 104 A W−1, and an external quantum efficiency of 3.1 × 107% when irradiated with incident light at a wavelength of 254 nm and a power density of 8 µW cm−2. Additionally, the device has a rise time of 43 ms and a fall time of 28 ms, respectively. By using FIB processing to etch and thin β‐Ga2O3 microflakes, this study effectively overcomes the poor controllability and low repeatability associated with the traditional mechanical exfoliation method, as well as the residual impurities from the plasma etching method. This opens up a new avenue for fabricating the high‐performance, low‐dimensional phototransistors based on β‐Ga2O3 with high repeatability and controllability. [ABSTRACT FROM AUTHOR]

Energy harvesting from extremely low frequency magnetic fields using magneto‐mechano‐electric (MME) harvesters enables wireless power transfer for operating Internet of Things (IoT) devices. The MME harvesters are designed to resonate at a fixed frequency by absorbing AC magnetic fields through a composite cantilever comprising of piezoelectric and magnetostrictive materials, and a permanent magnetic tip mass. However, this harvester architecture limits power generation because volume of the magnetic end mass is closely coupled with the resonance frequency of the device structure. Here, a method is demonstrated for maintaining the resonance frequency of the MME harvesters under all operating conditions (e.g., 60 Hz, standard frequency of electricity in many countries) while simultaneously enhancing the output power generation. By distributing the magnetic mass over the beam, the output power of the harvester is significantly enhanced at a constant resonance frequency. The MME harvester with distributed forcing shows 280% improvement in the power generation compared with a traditional architecture. The generated power is shown to be sufficient to power eight different onboard sensors with wireless data transmission integrated on a drone. These results demonstrate the promise of MME energy harvesters for powering wireless communication and IoT sensors. [ABSTRACT FROM AUTHOR]

Abstract Drug resistance in bacteria is becoming a significant threat to global public health, and the development of novel and efficient antibacterial compounds is urgently needed. Recently, rhodium complexes have attracted attention as antimicrobial agents, yet their antibacterial mechanism remains unknown. In this study, we observed that the dirhodium (II) complex Rh 2 Ac 4 inhibited Streptococcus. pneumoniae growth without significant cytotoxic side-effects on host cells in vitro. We subsequently investigated the antibacterial mechanism of Rh 2 Ac 4 using iTRAQ-based proteomics combined with cellular and biochemical assays. Bioinformatics analysis on the proteomic alterations demonstrated that six molecular functional groups, including metal ion binding and twelve metabolic pathways, were significantly affected after treatment with Rh 2 Ac 4. The interaction network analysis of metal ion binding proteins suggested that Rh 2 Ac 4 decreased the protein expression levels of SPD_1652, SPD_1590 and Gap, which are associated with haem uptake/metabolism. Cellular and biochemical assays further confirmed that Rh 2 Ac 4 could be taken up by bacteria via the PiuABCD haem-uptake system. The structurally similar Rh complex may compete with Fe-haem to decrease Fe-uptake via the PiuABCD system, disrupting iron metabolism to exert its antibacterial activity against S. pneumoniae. These data indicate that Rh 2 Ac 4 is a promising new drug for the treatment of S. pneumoniae infections. Graphical abstract Unlabelled Image Highlights • Dirhodium (II) complex Rh 2 Ac 4 inhibits S. pneumoniae growth without significant cytotoxic side-effects on host cell in vitro. • Rh 2 Ac 4 treatment globally affected metal ion binding and metabolic pathways in S. pneumoniae. • Rh 2 Ac 4 can compete with hemin for the metal-uptake via heme-uptake system PiuABCD and thus disrupts bacterial iron metabolism. [ABSTRACT FROM AUTHOR]

Racemic mixtures of four stereoisomers are easily formed via many fundamental organic transformations, but the direct utilities of these mixtures have been less studied and remain large challenges to date. In this work, we introduce a new method, i.e. divergent dynamic kinetic resolution, to achieve the separation of racemic mixtures of four stereoisomers. The hypothesis was proved by using a N‐heterocyclic carbene‐catalyzed benzoin reaction, which afforded two separable diastereomeric products bearing three consecutive stereocenters with good to excellent enantioselectivties. We believe that this resolution protocol will find applications in more transformations. Providing a good resolution: An N‐heterocyclic carbene‐catalyzed benzoin reaction was employed to achieve the divergent dynamic kinetic resolution of racemic mixtures of four stereoisomers, affording two separable diastereomeric tetralones bearing three consecutive stereocenters with good to excellent enantioselectivties. [ABSTRACT FROM AUTHOR]

The transition-metal-free lactonization of heteroaryl and alkenyl C-H bonds with carbon dioxide is reported to synthesize important coumarin derivatives in moderate to excellent yields. These redox-neutral reactions feature a broad substrate scope, good functional group tolerance, facile scalability, and easy product derivatization. [ABSTRACT FROM AUTHOR]

• The MAMD model of Ti2AlNb-based alloy B2 phase matrix was established. • The propagation behavior of microcracks in B2 matrix with different orientations was revealed by MD method. • Simulations and theoretical predictions result in consistent crack-tip behaviors. • Brittle fracture and ductile fracture exist simultaneously in the same material. The influence mechanism of crack orientation on B2 phase crack propagation behavior under cyclic loading is studied by using the meta-atom molecular dynamics (MAMD) method, and the simulation results are compared and verified based on the theory of linear elastic fracture mechanics. According to the different propagation speed of crack in B2 phase matrix, the crack propagation process can be divided into three stages: elastic stage, rapid propagation stage and slow propagation stage. The toughness or brittleness of the crack mainly depends on the competition between the cleavage fracture of the atomic bond and the plastic slip at the crack tip. The crack propagation behavior is obviously orientation dependent. Orientation I and orientation II expand in the form of ductile fracture. Orientation III shows obvious brittleness and expands in the form of cleavage fracture. Orientation IV (Orientation I-IV represent the four angles between the crack plane and the crystal orientation) shows both ductile fracture and brittle cleavage fracture. The defects and stress concentration at the crack tip provide a driving force for martensitic nucleation, and the hcp phase produced by martensitic transformation effectively increases the toughness of the crack. The simulation results of molecular dynamics are basically consistent with the theoretical prediction of linear elastic fracture mechanics. This suggests that the variation of the orientation could tune the crack tip plasticity and toughening in B2 phase matrix. [ABSTRACT FROM AUTHOR]

To reveal the non-thermal effect of electric current in macro-micro behaviors Ti–22Al–26Nb alloy sheet with bimodal initial structure, electrically-assisted (EA) near isothermal tensile tests and thermally-assisted (TA) tensile tests have been conducted comparatively at equivalent temperatures by adjusting the applied current-time curve. The stress responses, morphological evolution of constituent phases and the phase transformation behaviors have been characterized by means of EBSD and TEM. Result shows that EA tension is more effective in reducing deformation resistance, while TA tension plays a more important role in plasticity enhancement. The overall electrically-induced stress drop in EA tension increases monotonically with current density, but its non-thermal component first decreases with current density and then increases significantly from the critical value of 12.40A/mm2 in EA tension. The variation of the non-thermal stress drop during EA deformation is attributed to the competition between softening effect and strengthening effect of the electric current, viz. electric current causes softening effect by activating dislocation slip and inducing dislocation annihilation on one hand, and the electrically-driven dynamic precipitation of nanoscale O laths and dynamic globularization of O lamellae leads to additional strengthening effect on the other hand. Moreover, electric current promotes the process of O→B2 phase transformation from both thermodynamic and kinetic at 16.01–20.87 A/mm2. • Near isothermal EA tensile test was designed to rule out thermal effect in EP study. • EA tension shows greater effect in material softening rather than in plasticity enhancement. • Portevin Le-Chaterlier effect occurs in EA and TA tension but is suppressed at higher temperatures. • Dynamic precipitation and globularization of O phase weaken the non-thermal effect of EP. • The proportion of O.→B2 phase transformation increases by over 10 times in EA tension. [ABSTRACT FROM AUTHOR]

C75.5H70Cl2CoLi2O2, triclinic, P1̅ (no. 2), a = 13.1085(7) Å, b = 13.4704(7) Å, c = 18.8367(10) Å, α = 88.604(5)°, β = 88.255(4)°, γ = 68.282(5)°, V = 3088.3(3) Å3, Z = 1, Rgt(F) = 0.0666, wRref(F2) = 0.1743, T = 150 K. [ABSTRACT FROM AUTHOR]

• Recoverable point defects and unrecoverable clusters lead to hardening and strength reduction, respectively. • Twin boundary can effectively control radiation embrittlement through suppressing cluster defects. • Twin boundary could inhibit screw dislocation formation and hinder edge dislocation migration. • Twin boundary could ensure dislocation density after irradiation for strength reduction. Molecular dynamics (MD) simulations are applied to explore the defect evolution of single-crystal iron (SC Fe) and bicrystalline iron (BC Fe) under irradiation with 100 KeV energy at 673 K, and their mechanical properties and deformation mechanism under uniaxial tension at 300 K. The results show that twin boundary can significantly reduce the peak value of Frenkel defects, and enhance the defect clustering to inhibit the growth of clusters defects. The hardening behaviour is closely related to the fractions of recombinant point defects, while the unrecoverable point defects would transit to voids for the reduction of strength. Twin boundary can capture some small voids and inhibit the coelescence and growth of voids for reduction of strength loss. Additionally, it can effectively enhance the irradiation brittleness resistance through the inhabition of loss of dislocation density after irradiation. The plastic deformations of the SC Fe models depend on the operation of atomic slip system with high dislocation density, while irradiation will lead to the transformation of plastic deformation mechanism into emission and motion of shear dislocation loops (SDLs) with lower dislocation density. The plastic deformation mechanisms of the ∑3 (11–2) BC Fe are phase transformation, and SDLs emission and motion, while those of the ∑11 (332) BC Fe are only SDLs emission and motion. Irradiation hardly affects the plastic deformation of BC Fe. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, the plastic flow rules and fracture evolution mechanisms of the nearly O + B2 Ti–22Al–26Nb alloy during warm tension have been studied within a wide temperature range of 20–800 °C. The macro-micro deformation behaviors of the material have been investigated by means of SEM, EBSD and TEM. It is found that the stress-strain curve at 400 °C exhibits serrated patterns, indicating the occurrence of dynamic strain aging at mild temperature. The overall yield strength decreases and the uniform elongation increases with the temperature in general. However, an unexpected peak of yield strength and also an unexpected valley of uniform elongation are exhibited at 600 °C. Additionally, the uniform elongation shows a positive correlation with strain rate at 600 °C. With the comprehensive analyses of fracture surface characteristics, the morphological variation of the constituent phases and the dislocation structure evolution, the causations of the above phenomena are further explained as follows. The B2 phase is mainly responsible for deformation coordination between O laths with the original {110} B2 ∥(001) O orientation barely changed, and act as a media for propagating localized slip deformation to O grains. The abnormal mechanical responses at 600 °C are mainly attributed to the change of fracture mode caused by the precipitation of fine acicular O grains, while the softening mechanism at 800 °C is mainly dominated by the dynamic globularization of the O phase. • Serrated yielding and high elongation of 22.73% at 400 °C relates to dynamic strain aging. • Unexpected yield peak at 600 °C rises from the additional strengthening by nanoscale secondary O. • Unexpected elongation valley at 600 °C is due to quasi-cleavage fracture of B2–O lath interface. • B2 and O phase keeps {110} B2 ∥(001) O relation during warm tension via deformation coordination. • Enhanced globularization and coarsening of O laths causes flow softening at 800 °C. [ABSTRACT FROM AUTHOR]

The enhancement of radiation surface damage resistance of RAFM steel has been crucial to the failure protection and engineering application of nuclear fusion reactors. Here, a novel spatial extrusion–twist–extrusion (SETE) process was proposed to improve the radiation surface damage resistance through microstructures modification. The transmission electron microscope (TEM) and scanning electron microscope (SEM) were performed to investigate and reveal the behavior and mechanism enhancement of surface radiation damage. Crack and ablation were investigated in the initial sample, while only smaller bubbles and shallow depth channels were observed in the SETE-deformed samples. Additionally, the increase of dislocations and grain refinement caused by the SETE deformation, can effectively promote the recombination of irradiation defects, and weaken stress concentration by inhibiting the aggregation and growth of helium bubbles, hence inhibiting crack initiation. [ABSTRACT FROM AUTHOR]

A multi-scale model of dynamic impact fracture of Ni-based deformed superalloy was proposed based on molecular dynamics and finite element methods, and verified by experiments to reveal the synergistic effect of twin and phase boundaries on dynamic fracture properties and behavior from nanoscale to macroscale. The results show that the synergistic effect of twin and phase boundaries can effectively suppress the unfavorable brittle propagation in the nanoscale owing to the dispersed distribution of strengthening phase-induced reduction of the stress concentration on the twin boundary. The nucleation and emission of perfect dislocations, Shockley dislocations, and Frank dislocations promote ductile propagation, while the pile-up of stair-rod dislocations induced stress concentration leads to brittle propagation. In the macroscale, the synergistic effect of twin and phase boundaries can effectively inhibit the loss of dynamic fracture toughness, and impede crack initiation and crack propagation through the reduction of Mises stress concentration and the decrease of maximum equivalent strain caused by the dispersed Ni 3 Al precipitates. The physical mechanism of the multi-scale crack propagation and fracture, and the influence law of dynamic fracture toughness of Ni-based deformed superalloy, can provide a guide to the failure prediction, protection, and development of aviation turbine blades. [ABSTRACT FROM AUTHOR]

The terahertz technology has attracted considerable attention because of its potential applications in various fields. However, the research of functional devices, including polarization converters, remains a major demand for practical applications. In this work, a reflective dual-functional terahertz metadevice is presented, which combines two different polarization conversions through using a switchable metasurface. Different functions can be achieved because of the insulator-to-metal transition of vanadium dioxide (VO2). At room temperature, the metadevice can be regarded as a linear-to-linear polarization convertor containing a gold circular split-ring resonator (CSRR), first polyimide (PI) spacer, continuous VO2 film, second PI spacer, and gold substrate. The converter possesses a polarization conversion ratio higher than 0.9 and a bandwidth ratio of 81% in a range from 0.912 THz to 2.146 THz. When the temperature is above the insulator-to-metal transition temperature (approximately 68 °C) and VO2 becomes a metal, the metasurface transforms into a wideband linear-to-circular polarization converter composed of the gold CSRR, first PI layer, and continuous VO2 film. The ellipticity is close to âˆ'1, while the axis ratio is lower than 3 dB in a range of 1.07 THzâ€"1.67 THz. The metadevice also achieves a large angle tolerance and large manufacturing tolerance. [ABSTRACT FROM AUTHOR]

• A small Mo 2 -ZnP molecule catalyzes efficient photoreduction of H 2 O to H 2. • Multi electron transfer pathways broaden the energy thresholds of photoreaction. • Coupling two one-electron transfers to two-electron reduction for hydride transfer. • Single molecular photosystems mimicking Photosystem I for conversion of NAD+ to NADH. Bioinspired solar-chemical energy conversion has long been challenged by chemists with searching for effective synthetic photocatalysts. Herein we show that powered by visible light, molecular photocatalysts developed by integrating zinc porphyrin (ZnP) with a quadruply-bonded Mo 2 unit enables hydrogen evolution from water in high yields up to 200 mmol g−1 with TON = 640. Remarkably, this unimolecular Mo 2 -ZnP device catalyzes efficiently photoreduction of nicotinamide adenine dinucleotide (NAD+) to NADH, the reducing equivalent for enzymatic reduction of CO 2 in natural photosynthesis. Evidently, this Mo 2 -ZnP photosystem has the capability of accumulating up to four electrons and two protons for two-electron reduction. Mechanistic investigations reveal that the photoreduced zinc phlorin and chlorin-phlorin anions are the catalytic intermediates for hydride transfer to the substrates, which mimics functionally the hydroquinone state of flavin adenine dinucleotide in photosystem I. The understandings gained in this study are valuable for engineering photocatalysts for solar fuel production. [ABSTRACT FROM AUTHOR]

In the article "Enhancement-Mode Phototransistors Based on β-Ga2O3 Microflakes Fabricated by Focused Ion Beams" published in Advanced Optical Materials, the authors Huarong Yang, Hua Yu Feng, and their colleagues introduce a new method for etching and thinning β-Ga2O3 microflakes using focused ion beam (FIB) processing. By controlling the thickness of the microflake, they are able to transition the β-Ga2O3 phototransistor from depletion mode to enhancement mode, resulting in improved performance. This method, which utilizes O2 adsorption and interfacial charge depletion, demonstrates excellent results for enhancement-mode phototransistors. [Extracted from the article]

The effects of shear deformation at 1173 K on the mechanical properties and deformation mechanism of pure tungsten are investigated by molecular dynamics (MD). The results show that the shear deformation of pure tungsten is dominated by dislocation multiplication and slip band deformation. The shear angle has a significant effect on the mechanical properties of pure tungsten. The yield strength is 4.21 Gpa at a shear angle of 11 ∘ , and it increases significantly to 11.84 Gpa while the shear angle increasing to 27 ∘ . In the plastic deformation stage, the stress–strain curve shows obvious oscillation due to the interaction of dislocations in the single-crystal tungsten and the effect of strain strengthening. In addition, the evolution of dislocation and twining in the compression system against shear angle indicates the variation of deformation behavior. When the shear angle is 11 ∘ , the lengths of dislocation 1/2 〈 1 1 1 〉 and 〈 1 0 0 〉 increase to a peak rapidly, which illustrates dislocation strengthening. However, when the shear angle is more than 11 ∘ , the decrease of dislocation length and the appearance of twins along 〈 1 1 1 〉 direction demonstrate the twining accompanied with dislocation tangling, resulting in the additional increase of strength. [ABSTRACT FROM AUTHOR]

The article reports that flavivirus induces and antagonizes antiviral RNA interference (RNAi) in both mammals and mosquitoes. Topics discussed include the nonstructural protein NS2A of dengue virus-2 (DENV2) act as a viral suppressor of RNAi (VSR), mutant DENV2 induced Dicer-dependent production of abundant DENV2-derived siRNAs in differentiated mammalian cells and VSR-disabled DENV2 showed severe replication defects in mosquito and mammalian cells and in mice.

Increasing effort has been made towards the asymmetric total synthesis of rotenoid natural products owing to their impressive biological and pharmaceutical activities. Here we report the modular asymmetric total synthesis of rotenoid natural products. The concise construction of the cis-fused tetrahydrochromeno[3,4-b]chromene core structure of rotenoids through N-heterocyclic carbene-catalyzed dynamic kinetic resolution is achieved, and a series of annulation products containing rotenoid key structures are rapidly assembled using this method. More importantly, the protocol enables the modular synthesis of a variety of rotenoid natural products in a highly convergent fashion, and the concise asymmetric total synthesis of tephrosin, the first asymmetric total synthesis of 12a-hydroxymunduserone, milletosin, and 12a-hydroxyrotenone, and the formal synthesis of deguelin are accomplished. Rotenoid natural products have attracted interest as synthetic targets. Here N-heterocyclic carbene-catalysed dynamic kinetic resolution is used to rapidly and enantioselectively assemble the rotenoid core, enabling the modular asymmetric total synthesis of several rotenoid natural products [ABSTRACT FROM AUTHOR]

A series of three Mo2 dimers bridged by a meta‐phenylene group has been studied in terms of electronic coupling (EC) and electron transfer (ET) in comparison with the para isomers. Optical analyses on the mixed‐valence complexes indicate that by replacing a para‐phenylene bridge with a meta one, the EC between the two Mo2 centers is dramatically weakened; consequently, the ET rates (ket) are lowered by two to three orders of magnitude. In the para series, the EC parameters (Hab) and ET rates (ket) are greatly affected by O/S atomic alternation of the bridging ligand. However, for the meta analogues, similar EC and ET parameters are obtained, that is, Hab=300–400 cm−1 and ket≈109 s−1. These results suggest that through‐σ‐bond and/or through‐space coupling channels become operative as the π conjugation is disabled. DFT calculations reveal that destructive quantum interference features seen for the meta series arise from the cancellation of two π‐conjugated coupling pathways. Quantum constructive vs. destructive effects: Optical analysis of Mo2 mixed‐valence donor‐bridge‐acceptor systems indicates that a meta phenylene bridge lowers the electron‐transfer rate by two to three orders of magnitude with respect to the para analogues. DFT calculations reveal that the destructive quantum interference features arise from the cancellation of two coupling pathways. [ABSTRACT FROM AUTHOR]

The aim of the present study was investigate the association of the severity of emphysema of patients with chronic obstructive pulmonary disease (COPD) with airway inflammation and the COPD-specific comorbidity test (COTE) index. A total of 94 patients with COPD were divided into four groups according to the severity of their emphysema; in each patient, comorbidities were recorded and inflammatory biomarkers, including MMP-9 and TIMP-1 were determined in circulating blood. The unbalanced proportion of MMP-9 and its inhibitor, TIMP-1, led to the airway inflammation and lung remodeling in the patients with COPD. A total of 80.85% of the patients had emphysema of different degrees. The quantity of male patients and the smoking index in the three emphysema groups were significantly higher than those in the non-emphysema group (F=7.67 and 5.42, P<0.05). The level of the predicted percent offorced expiratory volume in 1 sec in the non-emphysema group were significantly higher than those in the emphysema group (4.33; P<0.05), and the level of D-dimer in the non-emphysema group was significantly lower than that in the mild and moderate emphysema groups (F=9.38, P<0.05). The low-attenuation area score was negatively correlated with inhaled bronchodilators (r=−0.240, P=0.007) but positively correlated with the frequency of acute exacerbations in the previous year (r=0.211, P=0.001). In terms of treatment, the use of systemic hormone therapy in the emphysema group was more frequent than that in the non-emphysema group (F=6.21, 12.92 and 4.08, P<0.05). The level of MMP-9 was significantly higher in COPD patients with >3 comorbidities, a COTE index of ≥4 and cardiovascular disease as well as coronary heart disease (t=6.40, 2.53, 3.65 and 2.90, P<0.05). The level of MMP-9 was positively correlated with the neutrophilic granulocyte percentage, the number of comorbidities and the COTE index (r=0.193, 0.402 and 0.311, P<0.01). The severity of emphysema in patients with COPD was correlated with the persistence of inflammatory factors in the circulating blood and the frequency of acute exacerbations. It was indicated that MMP-9 has a critical role in numerous comorbidities of COPD. [ABSTRACT FROM AUTHOR]

Background/aim: This study performed typing of chronic obstructive pulmonary disease (COPD) using high-resolution computed tomography (HRCT) to determine the association with smoking, matrix metalloproteinases, and common comorbidities. Materials and methods: The study enrolled 94 hospitalized patients. Participants were divided into a group of 69 current and former smokers (group A) and a group of 25 that had never smoked (group B). Patients were also divided into 3 categories according to the degree of emphysema and bronchial wall thickness using HRCT to determine the association with levels of matrix metalloproteinase 9 (MMP-9) and TIMP-1, as well as associated comorbidities. These three categories were: type A - no or mild emphysema, with or without bronchial wall thickening; type E - emphysema without bronchial wall thickening; and type M - both emphysema and bronchial wall thickening. Results: The low attenuation area (LAA) scores in group A patients were higher than those in group B (t = 2.86, P < 0.01); correlation analysis showed that smoking was associated with a decline of the forced expiratory volume in 1 s and forced vital capacity ratio (FEV1/FVC%) and higher LAA scores in patients with COPD (F = 4.46, F = 8.20, P < 0.05). The levels of MMP-9 in group A were higher than those in group B (t = 3.65, P < 0.01). Among COPD patients with more than 3 comorbidities, there were statistically significant differences in both the smoking group and the nonsmoking group (chi-square = 12.08, P < 0.01). When compared to type A patients, who had coincident cardiovascular diseases in the smoking group, patients of type M and E showed statistically significant differences (F = 2.42 and 2.12, P < 0.05). Conclusion: Emphysema was more severe in smokers. Metalloproteinase levels in smokers were higher than those in nonsmokers. Moreover, comorbidities were more severe in smokers. [ABSTRACT FROM AUTHOR]

The discovery of new reaction modes mediated by easily available substrates is an important research topic in organic synthesis. Allyl ketones and related compounds have been demonstrated to undergo γ- or α-selective additions to different electrophiles. We disclose here the Brønsted base-catalyzed reaction of allyl ketones and alkynyl 1,2-diketones, which undergo a unique α-selective addition/intramolecular aldol-type annulation/C–C bond cleavage process, and a series of 2-acyloxycyclopent-3-enones can be obtained under very mild conditions. [ABSTRACT FROM AUTHOR]

Four asymmetrical self-assembled monolayers (SAMs) consisting of two subunits with different Rh2 building blocks present a pronounced rectifying behavior. The rectification ratio (RR) increases on increasing the redox potential difference between the two Rh2 subunits, and the rectifying direction can be reversed by reordering the subunits in the assembly. [ABSTRACT FROM AUTHOR]

Three novel asymmetrical dimolybdenum dimers, [Mo2(DAniF)3]2(μ-OOCCOS) (DAniF = N,N′-di(p-anisyl)formamidinate) ([OO–OS]), [Mo2(DAniF)3]2(μ-S2CCO2) ([SS–OO]), and [Mo2(DAniF)3]2(μ-SSCCOS) ([SS–OS]), have been synthesized and characterized by either single-crystal X-ray crystallography or 1H NMR spectroscopy. The structural asymmetry for these compounds gives rise to a redox asymmetry, which enlarges the potential separation (ΔE1/2) between the two [Mo2] units. The mixed-valance (MV) species [OO–OS]+, [SS–OO]+ and [SS–OS]+, prepared by one-electron chemical oxidation of the neutral precursors, exhibit an intense and symmetrical intervalence charge transfer (IVCT) absorption band in the near-IR region, along with the high energy metal (δ) to ligand (π*) (ML) and ligand (π) to metal (δ) charge transfer (LMCT) absorptions. The LMCT band, which is absent in the neutral precursors, is reflective of the cationic [Mo2]+ unit in the MV species; therefore, it is evidenced that in the MV complexes optical electron transfer from the electron donor to acceptor occurs, while the thermal process is energetically unfavorable. The C(1)–C(2) bonds (1.44–1.48 Å) that connect the two [Mo2] units are significantly shorter than a C–C single bond, showing that the two Mo2 centers are strongly coupled. For the series, TD-DFT calculations show that the molecular orbitals have an unsymmetrical charge density distribution over the two dimolybdenum sites. For each of the complex systems, the calculated orbital energy gaps, SOMO(δ−δ)–LUMO(bridging ligand π*), HOMO−8(bridging ligand π)–SOMO(δ−δ) and SOMO(δ−δ)–HOMO−1(δ + δ), are in good agreement with the observed MLCT, LMCT and IVCT absorption band energies, respectively. The consistency in energy between the IVCT band and the SOMO(δ−δ)–HOMO−1(δ + δ) gap permits assignment of the MV complexes to Class III in the Robin–Day scheme. [ABSTRACT FROM AUTHOR]

Introduction: The past decade has provided striking insights into a newly identified subset of B cells known as regulatory B cells (Bregs). In addition to producing antibody, Bregs also regulate diseases via cytokine production and antigen presentation. This subset of B cells has protective and potentially therapeutic effects. However, the particularity of Bregs has caused some difficulties in conducting research on their roles. Notably, human B10 cells, which are Bregs that produce interleukin 10, share phenotypic characteristics with other previously defined B cell subsets, and currently, there is no known surface phenotype that is unique to B10 cells. Methods: An online search was performed in the PubMed and Web of Science databases for articles published providing evidences on the role of regulatory B cells in digestive system diseases. Results and Conclusions: Abundant evidence has demonstrated that Bregs play a regulatory role in inflammatory, autoimmune, and tumor diseases, and regulatory B cells play different roles in different diseases, but future work needs to determine the mechanisms by which Bregs are activated and how these cells affect their target cells. [ABSTRACT FROM AUTHOR]

FoxA transcription factors play vital roles in regulating the expression of organ-specific genes. BmSGF1, the sole FoxA family member in Bombyx mori , is required for development of the silk gland. However, the function of BmSGF1 in development of the nervous system in the silkworm remains unknown. Here, we show that the amino acids sequence of BmSGF1 is evolutionarily conserved in its middle region from Trichoplax adhaerens to human and diverged from the homologues in most other species in its N-terminal region. BmSGF1 expresses in the nervous system at the embryonic stage. Knockdown of Bmsgf1 by RNA interference (RNAi) results in abnormal development of axons. Therefore, our results demonstrate that BmSGF1 is an indispensable regulator for neurodevelopment. [ABSTRACT FROM AUTHOR]

Two, symmetrical, mixed-valence (MV), complex cations-{[Mo2(DAniF)3]2(μ-oxamidate)}+ ( 1+) and {Mo2(DAniF)3]2(μ-dithiooxamidate)}+ ( 2+; DAniF= N,N′-di( p-anisyl)formamidinate)-are significantly differentiated in terms of electronic coupling between the two [Mo2] units. For 1+ the intervalence (IV) charge-transfer band in the near-IR spectrum is truncated in half on the low-energy side as predicted for MV compounds at the Class II-III limit (2 Hab/ λ=1; for which Hab=electronic coupling matrix element and λ=reorganization energy). In contrast, the very strongly coupled analogue 2+, as indicated by 2 Hab/ λ=3.5 (> >1), exhibits a higher energy and more symmetrical IV band. As rare examples, this pair of MV species shows distinct optical behaviors for MV systems crossing the Class III region. Optical analysis and DFT calculations are carried out to elucidate the transformation from vibronic to electronic vertical transition. [ABSTRACT FROM AUTHOR]

Summary: Objectives: MicroRNAs (miRNAs) are endogenous small non-coding RNAs that negatively regular target gene expression by RNA interference. The processing of the pre-miRNA hairpin generates a miRNA duplex, which consists of a miRNA (guide strand) and a miRNA∗ (passenger strand). miR-31 is an oncogenic miRNA and is up-regulated in oral squamous cell carcinoma (OSCC). miR-31∗ shows a high level of conservation across species and, based on this, this study hypothesized that miR-31∗ is a functional miRNA. Materials and Methods: The expression of miR-31 and miR-31∗ in OSCC tissues and oral cells were analyzed. Functional studies were performed on OSCC cells. Results: miR-31∗ is up-regulated in OSCC tissues, but its expression is less abundant than miR-31. miR-31∗ decreases the proliferation and migration of both SAS and Fadu cells. Furthermore, miR-31∗ targets the 3′UTR of RhoA and is able to down-regulate RhoA expression. Knockdown of RhoA expression is known to decrease the proliferation and migration of OSCC cells. However, up-regulation of both miR-31 and miR-31∗ by delivery of pre-mir-31 does still enhance OSCC oncogenicity. Conclusion: miR-31∗ is a functional miRNA involving in regulating RhoA, and the activity of miR-31∗ ’s activity seems to counteract the functions of miR-31 during OSCC tumorigenesis. [ABSTRACT FROM AUTHOR]

J Oral Pathol Med (2011) 40: 560–566 Backgrounds:  MicroRNAs are small noncoding RNAs involved in posttranscriptional gene regulation, which play an important role in both physiological functioning and pathological progression. The miR‐221/miR‐222 microRNA family has been shown to be related to the neoplastic process in a number of different types of cancers; nevertheless, its function in oral squamous cell carcinoma (OSCC) remained uncertain. Materials and Methods:  Paired OSCC and matched noncancerous oral mucosa were examined for miR‐221/miR‐222 expression using quantitative reverse‐transcription PCR. Ectopic expression of miR‐221/miR‐222 by lentiviral infection was investigated to explore its in vitro and in vivo impact on the oncogenic phenotype and the expression of various target genes. The expression of Cip/Kip cell cycle regulator p27 in tumors was analyzed with immunohistochemistry. Results:  The expression levels of miR‐221 and miR‐222 were highly correlated in OSCC. Increased miR‐221/miR‐222 expression was found in 40% of OSCC tissues. The ectopic expression of miR‐221 or of miR‐222 increased growth and anchorage‐independent colony formation of OSCC cell lines. It also resulted in an increase in the tumorigenesis of an OSCC cell line in nude mice. Western blot analysis suggested that p27 and p57 might be the targets of miR‐221/miR‐222. p27 expression was reversely associated with the miR‐221 and miR‐222 expression level in OSCC tissues. Conclusions:  Our findings suggested that increased miR‐221/miR‐222 expression was associated with the OSCC cell growth. [ABSTRACT FROM AUTHOR]

The experiments and molecular dynamics simulations were employed to further understand the morphology evolution and failure mechanism of the TA15/Ti 2 AlNb interface. The results show that the asymmetric diffusions, caused by the difference of the diffusion coefficient and crystal structure, have played a significant role in the microstructure and mechanical properties. The diffusivity of Ti elements from TA15 was much better than those Nb and Al from Ti 2 AlNb base alloy owing to its higher diffusion coefficient. The macro joints are brittle fractures near the TA15 base zone, and excessive holding time will reduce the tensile strength and plasticity of the joint while increasing the temperature can enhance the strength and plasticity due to the promotion of diffusion and improvement of the microstructure. However, the nano joints are ductile failures owing to size effects. Time has little effect on the mechanical properties of nano joint, while an increase in temperature could improve the strength and plasticity. The combination of MD simulations and experiments provides new approaches for the study of deformation mechanisms and microstructure evolution. • Element diffusion and distributions were investigated from the nanoscale to the microscale. • The asymmetric diffusion was revealed by the diffusion coefficient and crystal structure. • Two fracture behavior and mechanism of the joint were proposed under the different scale. • The fracture mechanism was determined by atomic diffusion and interface morphology. [ABSTRACT FROM AUTHOR]

The molecular dynamics (MD) simulation is performed to obtain the mechanical properties and plastic deformation mechanism of bicrystal structural tungsten (BS W) with equilibrium grain boundaries (EGBs) and non-equilibrium grain boundaries (NEGBs) under tension at different strain rates. The BS W with NEGBs has shown excellent comprehensive mechanical properties, and its yield strength is only about 1.5 Gpa (~10%) lower than that of the BS W with EGBs. The yield strain of BS W with NEGBS is about double than that with EGBs. The micro-deformation mechanisms for BS W with NEGBs under tension are dislocation emission and movement, GBs interaction, and phase transition. However, the failure modes of BS W with EGBs are intergranular brittle fracture of crack near the GBs, and the strain rate has little effect on the fracture. The phase transition mechanism for BS W with NEGBs under the tension loading strain rate of 0.0001 ps−1 is atomic slippage, but that of 0.001 ps−1 is stress concentration induced quasi-reconstructive phase transition. At the loading strain rate of 0.0001 ps−1, dislocation emission and movement to the GBs would form the non-slippable crack dislocations for crack initiation. However, at the loading strain rate of 0.001 ps−1, the crack propagation is considered as a zigzag-shaped form on account that the phase transition induced stress relaxation. The NEGBs could improve plasticity without sacrificing strength, providing a theoretical method for nano-structure design, material modification, and sustainable material plain. Unlabelled Image • Comparing with the NC W with EGBs, that with NEGBs could significantly improve plasticity with a small sacrificing strength. • The strain rate has little influence on the mechanical properties and deformation mechanism of NC W with EGBs. • Two-phase transition mechanisms, atomic-slip, and stress concentration induced. • Two different fracture mechanisms, intergranular fracture, and crack propagation. [ABSTRACT FROM AUTHOR]

The effect of temperatures (1173–1233 K) on the diffusion welding process of the body-centered cubic titanium and the orthorhombic Ti 2 AlNb interface (B 2 –O interface) is investigated and analyzed using molecular dynamics. The result shows that Nb and Al atoms are the primary diffusive atoms in the orthorhombic single-crystal Ti 2 AlNb (O phase), and the diffusive distances of Ti atoms in the Β 2 phase are significantly higher than that of Nb and Al atoms in the O phase. The atomic diffusion within the O phase is downhill diffusion, aggregation and interface formation controlled by Nb and Al atoms. As the temperature increases from 1173 to 1233 K, the average diffusion distances during 900 ps of Nb and Al atoms in the O phase are increased from 1.4 nm to 1.9 nm, while those of Ti atoms during 900 ps in the B 2 phase are increased from 2.8 nm to 3.3 nm. The modified Arrhenius model considering the pressure effect is established to accurately solve the diffusion activation energy. The significant higher diffusion activation energy, and lower diffusion coefficient and diffusion prefactor of the orthorhombic single-crystal Ti 2 AlNb result in shorter atomic diffusive distances in the O phase than that of the B 2 phase. Image 1 • The asymmetric atomic diffusion in the B 2 –O interface is investigated at the atomic scale via molecular dynamics. • The atomic diffusivities are determined by the average atomic diffusion coefficient and activation energy. • Temperature-induced concentration variations play an important role in diffusion thickness and mechanism. • The modified Arrhenius relationship is derived to accurately solve the diffusion activation energy. [ABSTRACT FROM AUTHOR]