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This work describes the synthesis of GO, rGO and their nanocomposites with PEO. GO and rGO were prepared by the modified Hummers method and in-situ reduction of GO utilizing green reductant L (+) Ascorbic acid. The nanocomposites were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Thermogravimetric Analysis (TGA), and Universal Testing Machine (UTM). FT-IR and XRD confirmed the synthesis of GO and rGO. FE-SEM confirmed the uniformly exfoliated GO and rGO nanosheets in the polymer matrix. Hydrogen bonding was the main interaction mechanism for GO with PEO while no interaction was detected by FT-IR for rGO. Enhanced thermal stability was observed for both GO/PEO and rGO/PEO nanocomposites. The mechanical analysis showed an increase in Young’s modulus, tensile strength, and elongation at break for GO/PEO nanocomposites, which is attributed to the homogeneous dispersion and hydrophilic hydrogen bonding interaction of GO with PEO.

In this investigation, the practicability of utilizing 3-aminopropyl triethoxysilane (3-APTES) crosslinked chitosan (Ch)/graphene oxide (GO) membranes were explored for adsorptive removal of anionic dyes from aqueous medium. Membranes were successfully fabricated through solution casting technique. Strong interactions amongst matrix (chitosan), 3-APTES, polyvinylpyrrolidone (PVP) and GO were confirmed by Infrared spectroscopy. Thermal stability of the chitosan was improved by adding graphene oxide and results were verified via thermogravimetric (TGA) analysis. Swelling and hydrolytic results confirmed that 2 %-Ch/PVP was a stable membrane while increasing the amount of 3-APTES in the chitosan nanocomposites membrane decreased its stability in aqueous medium. The adsorption characteristics of the membranes were evaluated by the adsorption of Congo red (CR) dye from aqueous medium. The adsorbent can remove 80% of CR from aqueous medium and follows second order kinetics. This study outlines the possibility of exploring green membranes which can be easily fit in various flow systems.

In the study, the layered double hydroxide (LDH) of NiZnFe and its composites with date-palm biochar (LDH-DPb) and carbon nanotubes (LDH-cnt) were synthesized for adsorbing reactive black 5 (RB5) dye from aqueous solutions. In the first 5 min, rapid adsorption was followed by a gradual increase in both dye uptake and removal efficiency of up to 60 min of starting time. In the investigated pH range (3.0–8.0), the removal efficiency linearly decreased while the sorption capacity linearly increased for all three adsorbents as their doses increased to 0.3 or 0.4 g following a decreasing trend up to 0.6 g. By increasing the initial RB5 concentration from 10 to 100 mg L−1, the removal efficiency linearly decreased. A nearly perfect fitting of the pseudo-second-order kinetic model to the adsorption data was observed; however, the Elovich kinetic model showed the heterogeneous surface of adsorbents with chemisorption. At the solid–liquid interface, from a thermodynamics point of view, we obtained the nonspontaneous nature of the adsorption of RB5 dye of the studied adsorbents with an increased disorder, which supported the endothermic nature onto the studied adsorption process. Furthermore, a nearly perfect fitting of the Langmuir model was obtained to the adsorption data, thereby suggesting the monolayer adsorption of RB5 dye onto the studied adsorbents. In the Dubinin–Radushkevich model, a good agreement of the calculated adsorption capacities to the experimental values were observed and the chemical adsorption of RB5 dye on to the studied adsorbents was proposed based on E (8 – 16 kJ mol−1).

The nanofibrous membrane of polyacrylonitrile (NMP) was successfully synthesized after NaOH and NaHCO3 treatment aiming its functionalization using electrospinning for cadmium ion (Cd2+) adsorption. Field emission scanning electron microscopy (FE-SEM) revealed that small particles attached to the surface of functionalized PAN nanofibers. Equilibrium was attained after 60 min following a rapid uptake of Cd2+ with maximum adsorption capacity and percentage removal at an optimum solution pH of 7.0. The adsorbent dose of 0.3 g and 90 mg L−1 of initial Cd2+ concentration yielded the maximum adsorption capacity. The pseudo-second-order kinetic model was the best fitted to the adsorption data, indicating that the chemisorption is the controlling mechanism of adsorption. The physisorption was proposed based on the calculated values of the mean free energy of adsorption from the D–R isotherm (E

Calculations of AgSbTe2 thermoelectric material and 2d CdS/TiS2 and their heterostructures were carried out using Density Functional Theory in Cambridge Serial Total Energy Package code as implemented in Material Studio 2018 software. The work function, thermal transport, electronic and optical properties were calculated. The results revealed that the heterostructures are possible to be achieved with improved properties. The electronic and thermal transport properties were likened with the description of equations derived from Boltzmann transport theory and Mott expressed in the maximum achievable Figure merit. Orbital contributions from the electron movement show valence and conduction band atomic shells.

Flow of liquid over moving wedge is a crucial process in engineering applications because both the velocities of liquid and plate are proportional to each other in this process. Hence, it is very useful in preparation of paper, polymeric sheets and drawing of plastic films. We developed a mathematical model to report the hybrid nanoliquid flow past a wedge by incorporating the induced magnetic effect. Hybrid nanoliquid is taken by the mixture of magnetite-graphene oxide with water based nanoparticles. To obtain the nonlinear ordinary differential equations, preferable transformations are used and quantitative results are obtained using the Runge-Kutta-Fehlberg (RKF) fourth and fifth order schemes. Impact of controlling parameters in the problem statement is discussed through graphs and tables. Examination revealed that the higher magnetic parameter reduces the hybrid nanoliquid velocity, induced magnetic field, but the temperature field enhances. Also, when the wedge parameter value is negative, the Nusselt number and skin-friction values are higher compared to positive wedge values.

Metal/oxide support perimeter sites are known to provide unique properties because the nearby metal changes the local environment on the support surface. In particular, the electron scavenger effect reduces the energy necessary for surface anion desorption, thereby contributes to activation of the (reverse) Mars-van Krevelen mechanism. This study investigated the possibility of such activation in hydrides, carbides, nitrides, and sulfides. The work functions (WFs) of known hydrides, carbides, nitrides, oxides, and sulfides with group 3, 4, or 5 cations (Sc, Y, La, Ti, Zr, Hf, V, Nb, and Ta) were calculated. The WFs of most hydrides, carbides, and nitrides are smaller than the WF of Ag, implying that the electron scavenger effect may occur when late transition metal nanoparticles are adsorbed on the surface. The WF of oxides and sulfides decrease when reduced. The surface anion vacancy formation energy correlates well with the bulk formation energy in carbides and nitrides, while almost no correlation is found in hydrides because of the small range of surface hydrogen vacancy formation energy values. The electron scavenger effect is explicitly observed in nanorods adsorbed on TiH2 and Ti2O3; the surface vacancy formation energy decreases at anion sites near the nanorod, and charge transfer to the nanorod happens when an anion is removed at such sites. Activation of hydrides, carbides, and nitrides by nanorod adsorption and screening support materials through WF calculation are expected to open up a new category of supported catalysts., Supplementary material available at https://doi.org/10.1039/D1CP02068D

Ionic liquids (ILs) are promising electrolytes and many efforts have been made in basic scientific research as well as in applied research. In this contribution, we synthesised a variety of partly novel phosphonium ILs with different anions as well as with different compositions and lengths of the side chains of the cations. We measured a variety of their important transport properties such as viscosity, conductivity and diffusivity by means of stress-controlled rheology, impedance spectroscopy and PFGSTE NMR diffusometry. The results are analysed with respect to different models for derivation from ideal behaviours such as the ionicity and the (fractional) Walden rule depending on their molecular structure. These models are well established in the literature and are herein applied to rarely investigated but promising phosphonium ILs, with a particular emphasis placed on the effect of ether side chains. In comparison, the models show a qualitative correlation but distinct deviation in the quantification especially in the temperature dependent values and with other IL systems. These results aim to facilitate a better understanding of the IL properties depending on the molecular composition and by this way help to choose the ILs with optimal properties for practical applications.

This work examines the properties of polyvinyl alcohol (PVA)/starch film containing glycerol as a plasticizer under exposure to different nitrogen ion fluence. The prepared PVA/starch blend was irradiated with ion fluence from 3 × 1017 to 12 × 1017 ions.cm−2. From FTIR, the ion beam irradiation attack and weakens the C–H bond in PVA/starch blend. From XRD findings, the crystallite size of the blend decreased at 3 × 1017 ions/cm2 while it increased at higher fluence up to 9 × 1017 ion/cm2. This indicates the degradation of the blend at low ion fluence compared to crosslinking at high ion fluence. Also, the optical bandgap of the blend was decreased with an increase in ion fluence. Furthermore, the effect of N+ ions on some optical dispersion parameters is studied. The thermal stability of the PVA/starch blend shows a decrease in thermal stability upon irradiation with 3 × 1017 ions/cm2 compared to higher thermal stability at higher doses up to 9 × 1017 ions/cm2.

Oxygen sensitization and incorporation of ternary lead chalcogenide PbSe1-xTex thin films was investigated with two methods: adding oxygen via PbO to the bulk source alloy and post-deposition oxygen annealing. Characterization of the composition, structure, and morphology of these films confirmed that they follow Vegard's law for lattice parameter, and adding PbO to the source alloy did not impact the lattice parameter. However, adding PbO changed the electrical carrier properties observed in Hall effect measurements without forming any new oxide phase. Conversely, post-deposition annealing increased the lattice parameter due to oxygen incorporation into the lattice via interstitials in samples with appropriate grain boundary orientations. Morphological analysis revealed that PbSe0.8Te0.2 films demonstrated (100) texture, while PbSe0.6Te0.4 films demonstrated (111) texture with resulting grain boundary orientations more favorable to oxygen diffusion and incorporation. This varying oxygen incorporation from PbO source and oxygen annealing methods reveals trends that can lead to improved photodetector performance.

Heterostructures made from van der Waals materials provide a template to investigate proximity effects at atomically sharp heterointerfaces. In particular, near-field charge and energy transfer in heterostructures made from semiconducting transition metal dichalcogenides (TMD) have attracted interest to design model 2D "donor-acceptor" systems and new optoelectronic components. Here, using of Raman scattering and photoluminescence spectroscopies, we report a comprehensive characterization of a molybedenum diselenide (MoSe$_2$) monolayer deposited onto hexagonal boron nitride (hBN) and capped by mono- and bilayer graphene. Along with the atomically flat hBN susbstrate, a single graphene epilayer is sufficient to passivate the MoSe$_2$ layer and provides a homogenous environment without the need for an extra capping layer. As a result, we do not observe photo-induced doping in our heterostructure and the MoSe$_2$ excitonic linewidth gets as narrow as 1.6~meV, hence approaching the homogeneous limit. The semi-metallic graphene layer neutralizes the 2D semiconductor and enables picosecond non-radiative energy transfer that quenches radiative recombination from long-lived states. Hence, emission from the neutral band edge exciton largely dominates the photoluminescence spectrum of the MoSe$_2$/graphene heterostructure. Since this exciton has a picosecond radiative lifetime at low temperature, comparable with the energy transfer time, its low-temperature photoluminescence is only quenched by a factor of $3.3 \pm 1$ and $4.4 \pm 1$ in the presence of mono- and bilayer graphene, respectively. Finally, while our bare MoSe$_2$ on hBN exhibits negligible valley polarization at low temperature and under near-resonant excitation, we show that interfacing MoSe$_2$ with graphene yields a single-line emitter with degrees of valley polarization and coherence up to $\sim 15\,\%$., version 3, 5 figures

The behavior of single water drop impacting an oil layer on the deep water pool was recorded by using a high-speed camera. Heptane was used as the target liquid layer on the water pool. A particular phenomenon of double crown can be observed. The formation of double crown is not only related to the impact Weber number of the water droplet, but also the thickness of the oil layer. The critical Weber number for the formation of double crown decreases sharply as the decrease of the oil layer thickness. With the increase of Weber number and the decrease of oil layer thickness, there are four typical phenomena: single crown-jet, single crown-bubble, double crown-bubble and double crown- jet. Moreover, the effects of oil layer thickness and impact Weber number on surface bubble lifetime and the geometry size of crown, crater and jet were quantitatively analyzed.

In the present era of data-driven architectures like 5G, Internet of things (IoT), Artificial Intelligence (AI), etc, the requirement of fast-switchable memory storage is more than ever. Oxide resistive switches are considered to be a primary choice in the non-volatile memory design. In this work, we have engineered the conventional metal-insulator-metal (MIM) structure of an oxide memristor (Ag/ZnO/ITO) by inducing an additional oxide layer La0.7Sr0.3MnO3 (LSMO) at the interface between the active layer (ZnO) and Ag electrode. The presence of LSMO acts as a reservoir for the oxygen vacancies, easing the conducting filament formation process in ZnO, thereby enabling drastic improvement of the switching performance and offering reliable endurance over multiple switching cycles. First-principles-based calculations suggested the role of Oxygen vacancies in controlling the electronic state of ZnO and formation of vacancies in the resistive switching process, which is in agreement with the experimental observation. The current results pave ways for improving the switching performance of resistive memory circuits through simple structural engineering incorporation, which lies at the heart of oxide electronics.

A surfactant-free synthesis of precious metal nanoparticles performed in low boiling point solvents and in alkaline conditions has been reported recently. This strategy presents several advantages over alternative colloidal syntheses. The resulting nanoparticles are readily relevant for applications like catalysis and the synthetic process is compatible with large scale production. Alkaline mono-alcohols are here investigated as solvent and reducing agents to obtain colloidal Os nanoparticles by this low temperature (< 100 °C) surfactant-free synthesis. The effect of precursor (OsCl3 or H2OsCl6), precursor concentration (up to 100 mM), solvent (methanol or ethanol), presence or absence of base (NaOH) and addition of water (0 to 100 v.%) on the resulting nanomaterials is discussed. It is fond that no base is required to obtain Os nanoparticles as opposed to the case of Pt NPs for instance. The robustness of the synthesis for concentration of precursor up to 100 mM allows to perform X-ray total scattering with pair distribution function (PDF) analysis that shows that the 1-2 nm hcp NPs forms from chain-like [OsOxCly]-complexes.

Photoelectrochemical water splitting devices require semiconductor photoelectrode material fulfilling a number of primary requirements such as band gap, band edge alignment and corrosion resistance to electrolyte. Amorphous silicon carbide films, undoped and doped (P or B), were deposited on Si substrates by PECVD technology. The concentration of elements in the films was determined by RBS and ERD analytical method. Raman spectroscopy study of the SiC films were performed by using a Raman microscope and chemical compositions were analyzed by FTIR, before and after immersion of samples to aqueous pH 2.0 and pH 1.0 sulfuric acid electrolyte. Electrical properties of SiC films before and after immersion of samples to aqueous pH 2.0 and pH 1.0 sulfuric acid electrolyte were studied by measurement of the I–V characteristics on structure Al/SiC/Si/Al. Differences between Raman spectra, FTIR spectra and I–V characteristics before and after immersion to electrolyte are discussed.

The mesoscopic perovskite solar cells (PSCs) based on titanium oxide (TiO2) with a certified 25.2% efficiency are the forefront devices in the PSCs field. Hence, it can conclude the mesoporous titanium oxide (mp-TiO2) is one of the most promising candidates to use as an electron transport layer (ETL) in PSCs. Improving the conductivity of mp-TiO2 can consider as a simple route to motivate the electron extraction ability of this layer and increase the efficiency of PSCs. Herein, rubidium chloride (RbCl) was introduced as an additive source to boost the optoelectronic properties of mp-TiO2 ETL. It was observed through ETL modification with RbCl, the optical transmittance of mp-TiO2 remains constant but increases its electro-conductivity. Results showed that the morphology and crystalline properties of the perovskite layer with a modified ETL substrate is improved. It indicates a perovskite layer with enlarger grains and lower lead iodide (PbI2) surplus. Altogether, ETL modification brings a champion efficiency of 11.10% for hole transport layer (HTL)-free PSCs higher than that of 8.65% for the HTL-free PSCs based on pristine ETL. Besides, Modified PSCs compared to pristine PSCs showed higher stability response as a result of lower grain boundaries in the modified perovskite layer.

Alkaline earth (AE) metals are irreplaceable ingredients in the synthesis of AE metal-based antiperovskite oxides, and it can be achieved by a chemical reduction of a stable AE metal compound. In this study, hydrogen and carbothermal reduction of BaO and BaCO3 were employed, and we here report an undesirable side reaction creating barium hydroxide (Ba(OH)2) as the product of the reaction with the small amount of water in ultra-high purity inert gas used in the reduction processes. Such side reaction pathways and products are hardly identifiable in a high-temperature reaction; yet, systematic investigations on phase evolutions using X-ray diffraction, IR spectroscopy, and thermogravimetric analysis enabled the detection of Ba(OH)2·xH2O. Unintentional creation of alkaline earth metal oxides in intermediate and subsequent hydration even under a negligible amount of H2O may lead to an unexpected loss of alkaline earth metal element and, consequently, its deficiency in a desired final product.

This current paper presented a new candidate and potentially to improve the current membrane materials in water filtration process. With that, the primary materials used in this research study is layered double hydroxides (LDH) nanoclay which can be obtained from earth minerals and self-synthesized from inorganic salts were discussed thoroughly to help a better understanding of these materials. However, the current technologies of water separation were still lagging behind and ineffective especially in removal of divalent metal ions and multivalent salts. Infeasibility of reverse osmosis membrane make it not a viable option for divalent salts filtration. With that, nanofiltration (NF) membrane offered as an alternative to substitute available method. In this study, thin film nanocomposite (TFN) membranes were fabricated by incorporating layered double hydroxides (LDH) nanoclay. The LDH nanoclay with different loading ratio of 0, 0.05, 0.1, 0.15 and 0.2 were impregnated into polyamide layer on top of polysulfone substrates. The fabricated TFN were characterized in terms of physicochemical properties (SEM and FTIR) and membrane hydrophilicity (contact angle). After the addition of LDH, the morphological structures of TFN membranes were changed and the surface hydrophilicity was enhanced significantly. FESEM images displayed a typical ridge and valley morphology with nodule-like structures. As the LDH loading was increased, the contact angle decreased from 34.56˚ to 15.76˚ showing the surface hydrophilicity of membrane is improved. The separation performance of membrane was evaluated in terms of salt rejection ability by cross flow filtration system. The best performance NF membrane was found to be TFN 0.05 with high water flux and MgCl2 rejection with values of 24.18 L/m2.h and 91% respectively. This study has experimentally validated the potential of LDH materials in membrane process for improvement in water separation process.

Transition-metal-based nitrides and carbides have been widely studied for various applications because of their excellent mechanical, electrical, and catalytic properties. Although outstanding performances of Mo nitride and carbonitride synthesized by chemical reaction methods have been reported recently for catalytic applications, a metallic phase transition method for pre-deposited MoO3 precursor films, which is suitable for application to Si or metallic substrates, has rarely been reported. Herein, we investigate Mo nitride and carbonitride thin films synthesized via nitriding and carbonitriding of MoO3 films using two types of ammonium salt precursors, urea and ammonium carbonate (AC), in the chemical vapor deposition (CVD) process. The phase-changed crystalline films of Mo carbonitride via the urea reaction and Mo nitride via the AC reaction were determined to be MoC0.5N0.5 and MoN by X-ray diffractometry, respectively. Nevertheless, amorphous states of carbons and their related compounds, unreacted residual MoO3, and incompletely reacted MoO2 remained in the films, as determined by other thin film analyses. When the residual MoO2 was minimal, the films exhibited the lowest electrical resistivity, i.e., ∼10−4 Ω·cm for Mo carbonitride and ∼10−3 Ω·cm for Mo nitride, implying an optimum metallic phase transition. Our results pave the way for the nitriding and carbonitriding of transition metal oxides using ammonium salt precursors for a one-step reaction in the CVD process.

A comparison of physical properties and fluorescence quenching behavior between glycerol with a deep eutectic solvent (DES) and an ionic liquid (IL) in the presence of lithium salt as media is presented. It is reported earlier that addition of LiCl to the DES ChCl:Urea (composed of salt choline chloride and H-bond donor urea in 1 : 2 mole ratio) and addition of LiTf2N [Tf2N: (CF3SO2)2N] to the IL [C2C1im][Tf2N] ([C2C1im]: 1-ethyl-3-methylimidazolium), respectively, results in increase in the dynamic viscosity of the medium. However, as the concentration of the Li salt is increased, instead of decreasing, the bimolecular quenching rate constant (k_q) for quenching of pyrene fluorescence by nitromethane is observed to first increase and only then decreases within both the media. This unusual initial increase in quenching is hypothesized to the structural changes in the DES ChCl:Urea and the IL [C2C1im][Tf2N], respectively, as the Li salt was added. We tested this hypothesis by comparing this outcome with that within 1 wt% water in glycerol solution having similar viscosity as that of the DES ChCl:Urea. In complete contrast, irrespective of the temperature, k_q is found to decrease monotonically with increasing concentration of LiCl within 1 wt% water in glycerol media. The structural reorganization leading to anionic clustering within the media dominates in DES ChCl:Urea and IL [C2C1im][Tf2N] and overcomes the effect of increasing viscosity. Such anionic clustering is either absent or takes place at relatively lesser extent in LiCl added 1 wt% water in glycerol such that the charge transfer quenching process is dominated entirely by the viscosity in this media. The ionic nature of the IL and the high concentration of ions in the DES are deemed responsible for these outcomes. These findings highlight the unusual characteristics of ILs and DESs as solubilizing media.

The Z-scan technique was employed to explore the third-order nonlinear optical properties of disperse red 13 organic chromophore solutions in tetrahydrofuran. A continuous-wave He–Ne laser (632.8 nm) was used as a source of irradiation. The nonlinear absorption and nonlinear refractive index coefficients of this dye were investigated. The results showed that this dye has a good nonlinear response with its real and imaginary quantities of third-order susceptibility. The solutions showed negative nonlinear refraction. The best obtained value of the third-order susceptibility was 6.37 × 10–3 esu at a dye concentration of 3.15 × 10–4 mol/L. Moreover, the nonlinear optical properties were enhanced with higher dye concentrations, and an elevated trend in nonlinear absorption and nonlinear refractive index coefficients was observed. Also, it was found that the reverse saturable absorption was the main mechanism responsible for the two-photon absorption effect in DSR13/THF samples.

Lithium sulfur battery is one of the most promising applicants for the next generation of energy storage devices whose commercial applications are impeded by the key issue of shuttle effect. To overcome this obstacle, various of two-dimensional (2D) carbon-based metal-free compounds have been proposed to serve as anchoring materials for immobilizing soluble lithium polysulfides (LiPs), which however suffered from low electronic conductivity implying unsatisfactory performance for catalyzing sulfur redox. Therefore, we predicted metallic C5N monolayers, possessing hexagonal (H) and orthorhombic (O) phases, which exhibit excellent performances for suppressing the shuttle effect. First principles simulations demonstrate that O-C5N could serve as bifunctional anchoring material due to its strong adsorption capability to LiPs and excellent catalytic performance for sulfur redox with active sites from both basal plane and zigzag edges. Furthermore, the rate of Li2S oxidation over O-C5N is fast due to low energy barrier of 0.93eV for Li2S decomposition. While for H-C5N only N atoms locating at the armchair edges can efficiently trap LiPs and boost the formation and dissociation of Li2S during discharge and charge processes, respectively. The current work opens an avenue of designing 2D metallic carbon-based anchoring materials for Lithium sulfur battery, which deserves further experimental research efforts.

The magnetic behavior of rare-earth orthoferrite ErFeO3 single crystal can be controlled by low magnetic fields from a few to hundreds of Oe. Here we investigated high-quality ErFeO3 single crystal at the temperature range of 5 K-120 K, with two types of spin switching in the field-cooled-cooling (FCC) and field-cooled-warming (FCW) processes below the temperature of spin reorientation (SR) transition from Г4 to Г2 at 98 K-88 K. The magnitude of the applied magnetic fields could regulate two types of spin switching along a-axis of ErFeO3 single crystal but does not affect the type and temperature range of the SR transition. An interesting 'multi-step' type-II spin switching is observed in FCW under low magnetic fields (H ＜18 Oe) just below the SR transition temperature, which is associated with the interaction and the change of magnetic configurations from rare-earth and iron magnetic sublattices. When the magnetic field is lower than 15 Oe, the type-II spin switching in FCW process gradually changes to a continuous magnetic transition along the a-axis of the ErFeO3 single crystal. As the magnetic field is reduced to be less than 17 Oe, the type-I spin switching in the FCW process also transforms into a continuous magnetic transition. Understanding the magnetic reversal effects will help us explore the potential applications of these magnetic materials for future information devices.

The extent of the influence of an excess proton to the surrounding hydrogen bonds is estimated using IR spectroscopy of gas phase clusters.

Exploring the initial reactions of H-free and nitro-free energetic materials could enrich our understanding into the thermal decomposition mechanism of various energetic materials (EMs). In this work, two furoxan compounds, 3,4-dinitrofurazanfuroxan (DNTF) and benzotrifuroxan (BTF), were investigated to shed light on the decay mechanism of furoxan compounds based on the self-consistent charge density functional tight binding molecular dynamic simulations. Results show that DNTF and BTF decay in a unimolecular mechanism, and the transformation of furoxan ring to nitro group are suggested as a novel initial channel. Five initial steps of DNTF are observed, including NO2 loss and the N(O)-O bond cleavage of central and peripheral rings. The bond cleavage of peripheral rings dominates the decay at low temperature, while the central ring opening and C-NO2 dissociation governs the high temperature decay. Besides, NO2, CO and NO fragments are mainly yield at high temperature, while CO3N2 is dominant at low temperature. The three-stage characteristics of the exothermic of BTF decay are described under programmed heating conditions for the first time. Four initial steps of BTF were identified, including furoxan ring opening reactions and the breakage of 6-membered ring C-C bond. The cleavage of N(O)-O bond rules the initial step of BTF under different heating conditions, and the frequency increased with the temperature increasing. In addition, the amount of CON, ON and CO are higher at high temperature, while C2O2N2 shows a opposite trend. What obtained this work promote deepen insights into the complicated sensitivity mechanism of EMs.

We present a first-principle molecular dynamics study on the uptake and hydration of sulfur dioxide on the dry and wet fully hydroxylated surfaces of (0001) alpha-quartz, which are a proxy for suspended silica dust in atmosphere. The average adsorption energy for SO2 is ~10 kcal/mol on both dry and wet surfaces. The adsorption is driven by hydrogen bonds formation between SO2 and the interfacial hydroxyl groups (on dry silica), or with water molecules (in the wet case). In the dry system, we report an additional electrostatic interaction between the interfacial hydroxyl oxygen and the sulfur atom, which further stabilize the adsorbate. On dry silica, the interfacial hydroxyl group coordinates SO2 yielding to a surface bounded bisulfite (Si-SO3H) complex. On the wet surface, SO2 reacts with water forming bisulfite (HSO3-), and the latter remains solvated inside the adsorbed water layer. The hydration barrier for sulfur oxide is 1 kcal/mol and 3 kcal/mol on the dry and wet silica, respectively, while for the backward reaction (i.e., bisulfite to SO2) the barrier is 6 kcal/mol on both surfaces. The modest backward barrier rationalizes earlier experimental findings showing no SO2 uptake on silicates. These results underline the importance of the surface hydroxylation and/or of adsorbed water layers for the SO2 uptake and its hydration on silica. Moreover, the hydration to bisulfite may prevent direct SO2 photochemistry and be an additional source of sulfate: this is especially relevant in atmosphere subject to high level of suspend mineral dust, intense solar radiation and atmospheric oxidizers.

The glucagon-like peptide-1 receptor (GLP-1R) has broad physiological roles and is a validated target for treatment of metabolic disorders. Despite recent advances in GLP-1R structure elucidation, detailed mechanistic understanding of how different peptides generate profound differences in G protein-mediated signalling is still lacking. Here we combine cryo-electron microscopy, molecular dynamics simulations, receptor mutagenesis and pharmacological assays, to interrogate the mechanism and consequences of GLP-1R binding to four peptide agonists; glucagon-like peptide-1, oxyntomodulin, exendin-4 and exendin-P5. These data reveal that distinctions in peptide N-terminal interactions and dynamics with the GLP-1R transmembrane domain are reciprocally associated with differences in the allosteric coupling to G proteins. In particular, transient interactions with residues at the base of the binding cavity correlate with enhanced kinetics for G protein activation, providing a rationale for differences in G protein-mediated signalling efficacy from distinct agonists., The glucagon-like peptide-1 receptor (GLP-1R) can be targeted in the treatment of diabetes, obesity and other metabolic disorders. Here, the authors assess the molecular mechanisms of peptide agonists binding to GLP-1R and the responses elucidated by these ligands, including distinct kinetics of G protein activation.

The attachment of electrons is known to significantly influence some chemical and biological processes. The chemical differences between Schiff and Mannich bases are characterized by strong intramolecular hydrogen bonds, resulting from the presence of, respectively, single or double carbon–nitrogen bonds in the chelate rings. Differences are especially visible in the hydrogen transfer processes from molecular (O–H⋯N) to the proton transfer (O⋯H–N) forms. The reaction in a Schiff base occurs as an ordinary hydrogen transfer from a donor to an acceptor, while in a Mannich base the transfer of hydrogen occurs simultaneously with a C–N bond scission leading to an intermolecular complex. The attachment of electrons preserves the overall structural topology of the reactants; however, due to differences in electron affinities, reactions switch from endothermic to exothermic and reaction rates in the anionic systems are significantly higher. The difference in electron affinities for particular reactants comes from the fundamental differences in electron binding mechanisms, leading to the valence-bound or dipole-bound states. The observed mechanisms are closely related to the nature and size of the LUMOs of the parent molecules. The transition state of the Mannich base corresponds to the σ and π orbital conversion and possesses the characteristics of the valence-bound state and the dipole-bound electronic state.

We report the mass-selected threshold photoelectron spectrum (ms-TPES) of iminoborane (HBNH), generated by pyrolysis of borazine. The adibatic ionization energy (IE) of the X+ 2Π

The Hydroxymethyl (•CH2OH) radical is an important intermediate species in both atmosphere and combustion reaction systems. The rate coefficients for •CH2OH + 3O2 and (CH2OH + 3O2 (+H2O) reactions were calculated using Rice−Ramsperger−Kassel−Marcus (RRKM)/master equation (ME) simulation and canonical variational transition state theory (CVT) between the temperature range of 200 to 1500 K based on the potential energy surface constructed using CCSD(T)//ωB97XD /6-311++G(3df,3pd). The results show that •CH2OH + 3O2 leads to form CH2O and HO2 in the temperature 1000K). When water molecule added to the reaction favored the formation of CH2O and HO2 in all the temperature. The calculated rate coefficient for the •CH2OH + 3O2 (2.8×10-11 cm3 molecule-1 s-1 at 298K) is in good agreement with the previous experimental values (~1×10-11 cm3 molecule-1 s-1 at 298K). The rate coefficients for the water-assisted reaction (2.4×10-16 cm3 molecule-1 s-1 at 1000K) is at least 3-4 order magnitude smaller than the water-free reaction (6.2×10-12 cm3 molecule-1 s-1 at 1000 K). This result is consistent with the similar types of reaction system. Our calculations also predict that the effect of a single water molecule favors the formation of CH2O in the combustion condition however, the water-free reaction favors the formation of CH2O in the atmospheric condition. The current study helps to understand how a single water molecule changes the reaction mechanism and chemical kinetic behaviour under atmospheric and combustion conditions.

High-energy density and low cost sodium-ion batteries are being sought to meet increasing energy demand. Here, R-MnO2 is chosen as a cathode material of sodium-ion batteries owing to its low cost and high energy density. Structural transformation from the tunnel R-MnO2 to the layered NaMnO2 and electrochemical properties during the charge/discharge are investigated at the atomic level by combining the XRD and related electrochemical experiments. Na0.04MnO2 has a tunnel R-MnO2 phase structure, Na0.42MnO2 has a layered NaMnO2 phase structure, and Na0.04-0.42MnO2 is their mixed phase. Mn3+ 3d4[t2g(3)3dz2(1)3dx2-y2(0)] in the NaMnO2 loses one 3dz2 electron and the redox couple Mn3+/Mn4+ delivers 206 mA h/g during the initial charge. The case that the Fermi energy level difference between R-MnO2 and NaMnO2 lower than that between Na(12-x)/12MnO2 and NaMnO2 makes the potential plateau of R-MnO2 turning into NaMnO2 lower than that of Na(12-x)/12MnO2 to NaMnO2. This can be confirmed by our experiment from the 1st-2nd voltage capacity profile of R-MnO2 in the EC/PC (Ethylene carbonate/Propylene carbonate) electrolyte. The study would give a new view for production of sustainable sodium battery cathode material.

Oxylipins are potent biological mediators requiring strict control, but how they are removed en masse during infection and inflammation is unknown. Here we show that lipopolysaccharide (LPS) dynamically enhances oxylipin removal via mitochondrial β-oxidation. Specifically, genetic or pharmacological targeting of carnitine palmitoyl transferase 1 (CPT1), a mitochondrial importer of fatty acids, reveal that many oxylipins are removed by this protein during inflammation in vitro and in vivo. Using stable isotope-tracing lipidomics, we find secretion-reuptake recycling for 12-HETE and its intermediate metabolites. Meanwhile, oxylipin β-oxidation is uncoupled from oxidative phosphorylation, thus not contributing to energy generation. Testing for genetic control checkpoints, transcriptional interrogation of human neonatal sepsis finds upregulation of many genes involved in mitochondrial removal of long-chain fatty acyls, such as ACSL1,3,4, ACADVL, CPT1B, CPT2 and HADHB. Also, ACSL1/Acsl1 upregulation is consistently observed following the treatment of human/murine macrophages with LPS and IFN-γ. Last, dampening oxylipin levels by β-oxidation is suggested to impact on their regulation of leukocyte functions. In summary, we propose mitochondrial β-oxidation as a regulatory metabolic checkpoint for oxylipins during inflammation., Oxylipins are lipid mediators generated during infection for regulating inflammatory responses, but how they are removed is not completely clear. Here the authors show that cellular oxylipin removal is linked to mitochondria β-oxidation by CPT1, a mitochondria lipid importer protein, to serve as a metabolic checkpoint for oxylipin homeostasis and inflammation.

As the heaviest group 12 element known now, copernicium (Cn) often presents the oxidation states of +I, +II, and rarely +IV as in its homologue mercury. In this work we systematically studied the stability of some oxides, fluorides, and oxyfluorides of Cn by two-component relativistic calculations, and found that the CnF6 molecule with an oxidation state of +VI has an extraordinary stability. CnF6 may decompose into CnF4 by conquering an energy barrier of about 30 kcal/mol without markedly releasing heat. Our results indicates that CnF6 may exist under some special conditions.

Photoelectrochemical CO2 reduction by Cu2ZnSnS4 (CZTS) photocathodes is a potentially low-cost and high-efficiency CO2 conversion approach. However, the current CZTS-based photocathodes for the CO2 reduction reaction (CO2RR) are challenged by the active side reaction of the hydrogen evolution reaction (HER) and the incompatibility with efficient electrocatalysts. In this work, by means of density functional theory (DFT), we predict that a (220)-facet-suppressed kesterite CZTS could be an efficient photo-electro-integrated photocathode for formic acid production in the CO2RR. The results show that the competitive HER is mostly favored on the (220) facet. And the CO2RR for formic acid production on the (112) and (312) facets exhibits a thermodynamic energy barrier lower than 0.26 eV. Different from the d-band theory in metal electrocatalysts, it is found that the density of low energy unoccupied states in the S 3p orbital plays a key role in determining the CO2RR reaction path of the kesterite CZTS. Furthermore, two different trends of adsorption energy depending on the chemical characteristic of adsorbates are analyzed. Our study unveils the potential for selectively reducing CO2 into formic acid with kesterite CZTS and provides a possible route for manipulating the electrocatalytic properties of metal sulfide catalysts.

The simulation-based artificial neural networks (ANN) program is one of the suitable candidates from artificial intelligence simulation which can work to predict important ultrasonic and mechanical parameters in the glass field. This research is focused on exploring the validity of this system by comparing the prediction values from ANN with the experimental measurements and other theoretical models. The ANN simulation was effectively applied to a binary zinc-borate glass system with the composition of zZnO−(100-z)B2O3 where z = 0, 40, 45, 50, 55, and 60 mol%, which was fabricated by using the melt-quenching techniques. The increase of ZnO content caused the ultrasonic velocity and elastic moduli of the glasses to exhibit a decreasing trend. The bond compression theoretical calculation compared with the experimental measurement was considered to be satisfactory with the value of the coefficient R2 being around 0.92452 to 0.98492. The Makishima-Mackenzie calculation model concerning the experimental measurement of the elastic moduli and Poisson's ratio were between 0.86628 to 0.99786. The coefficient R2 value from the ANN simulation displayed on the density, ultrasonic velocity, and elastic moduli graph is around 0.9999 to 1.0000, which is considered to be very reasonable. The values predicted by this remarkable model proved that ANN simulation is suitable for use in glass research.

Cholesterol-mediated perturbations of membrane structural integrity are key early events in the molecular pathogenesis of Alzheimer’s disease (AD). In AD, protein misfolding (proteopathy) and pro-inflammatory conditions (immunopathy) culminate in neuronal death, a process enabled by altered membrane biophysical properties which render neurons more susceptible to proteopathic and immunopathic cytotoxicities. Since cholesterol is a principal neuronal membrane lipid, normal cholesterol homeostasis is central to membrane health; also, since increased cholesterol composition is especially present in neuronal myelin sheath (i.e. brain “white matter”), recent studies have not surprisingly revealed that white matter atrophy precedes the conventional biomarkers of AD (amyloid plaques, tau tangles). Employing extensive microsecond all-atom molecular dynamics simulations, we investigated biophysical and mechanical properties of myelin sheath membrane as a function of cholesterol mole fraction (χ_CHL). Impaired χ_CHL modulates multiple membrane properties including surface area per lipid, chain order, area compressibility and bending moduli, bilayer thickness, lipid tilt angles and tail interdigitation. High χ_CHL condenses and stiffens the membrane, changing permeability and altering interfacial water density; low χ_CHL increases membrane fluidity and disorder, modulating lipid tilt angles and enhancing bilayer leaflet interdigitation. These calculations provide a molecular-level understanding of myelin sheath susceptibility to pathology as an early event in the pathogenesis of AD.

Cholesterol is a crucial component of mammalian cell membranes that takes part in many vital processes. It is generally accepted that cholesterol stabilizes the membrane and induces transitions into ordered states. In contrast to expectations, we demonstrate that cholesterol can destabilize the membrane by creating a nanodomain around a perpendicularly embedded ultrashort carbon nanotube (CNT), and we show that cholesterol triggers the translocation of an ultrashort CNT through the cell membrane. Using atomistic simulations, we report the existence of a nanoscale domain around an ultrashort carbon nanotube within a crossover distance of 0.9 nm from the surface of the nanotube, where the properties of the bilayer are different from the bulk: the domain is characterized by increased fluctuations, increased thickness, and increased order of the lipids with respect to the bulk. Cholesterol decreases the thickness and order of lipids and increases the fluctuations with respect to a pure lipid bilayer. Experimentally, we confirm that cholesterol nanodomains provoke spontaneous translocation of nanotubes through a lipid bilayer even for low membrane tensions. A specially designed microfluidic device allows us to trace the kinetic pathway of the translocation process and establish the threshold cholesterol concentration of 20% for translocation. The reported nanoscale cholesterol-induced membrane restructuring near the ultrashort CNT in lipid membranes enables precise control and specific targeting of a membrane using cholesterol. As an example, it may allow for specific targeting between cholesterol-rich mammalian cells and cholesterol-poor bacterial cells.

Lithium-oxygen batteries (LOBs) with ultrahigh theoretical energy density have emerged as one appealing candidate for next-generation energy storage devices. Unfortunately, some fundamental issues remain unsettled, involving large overpotential and inferior rate capability, mainly induced by the sluggish reaction kinetics and parasitic reactions at the cathode. Hence, the pursuit of suitable catalyst capable of efficiently catalyzing the oxygen redox reaction and eliminating the side-product generation, become urgent for the development of LOBs. Here, we report a universal synthesis approach to fabricate a suite of mildly oxidized MXenes (mo-Nb2CTx, mo-Ti3C2Tx, and mo-V2CTx) as cathode catalysts for LOBs. The readily prepared mo-MXenes possess expanded interlayer distance to accommodate massive Li2O2 formation, and in-situ-formed light metal oxide to enhance the electrocatalytic activity of MXenes. Taken together, the mo-V2CTx manages to deliver a high specific capacity of 22752 mAh g-1 at a current density of 100 mA g-1, and a long lifespan of 100 cycles at 500 mA g-1. More impressively, LOBs with mo-V2CTx can continuously operate for 90, 89, and 70 cycles, respectively, under a high current density of 1000, 2000, and 3000 mA g-1 with a cutoff capacity of 1000 mAh g-1. The theoretical calculations further reveal the underlying mechanism lies in the optimized surface, where the overpotentials for the formation/decomposition of Li2O2 are significantly reduced and the catalytic kinetics is accelerated. This contribution offers a feasible strategy to prepare MXenes as efficient and robust electrocatalyst toward advanced LOBs and other energy storage devices.

In order to overcome the shuttling effect of soluble polysulfides in lithium-sulfur (Li-S) batteries, we have designed and synthesized a creative MoS2-MoO3/carbon shell (MoS2-MoO3/CS) composite by a H2O2-enabled oxidizing process under mild conditions, which is further used for separator modification. The MoS2-MoO3 heterostructures can conform to the CS morphology, forming two-dimensional nanosheets, and thus shorten the transport path of lithium ion and electrons. Based on our theoretical calculations and experiments, the heterostructures show strong surface affinity toward polysulfides and good catalytic activity to accelerate polysulfide conversion. Benefiting from the above merits, the Li-S battery with a MoS2-MoO3/CS modified separator exhibits good electrochemical performance: it delivers a high discharge capacity of 1531 mAh g-1 at 0.2 C; the initial capacity can be maintained by 92% after 600 cycles at 1 C, and the discharge capacity decay rate is only 0.0135% per cycle. Moreover, the MoS2-MoO3/CS battery still achieves good cycling stability with 78% capacity retention after 100 cycles at 0.2 C with a high sulfur loading of 5.9 mg cm-2. This work offers a facile design to construct the MoS2-MoO3 heterostructures for high-performance Li-S batteries, and may also improve one's understanding on the heterostructure contribution during polysulfide adsorption and conversion.

Polypyrrole (PPy)-coated tin oxide and silica oxide composite nanomaterials are synthesized by hydrothermal method and electrochemical in situ polymerization. Herein, the effect of PPy contents on the structure and properties of PPy/SnO2@SiO2 nanocomposites is investigated. With the increase of the pyrrole monomer content, the thickness of the cladding layer of PPy/SnO2@SiO2 core–shell structure increases gradually. And the results indicate that the sample containing 28 wt% PPy exhibits the stable structure of composite and high initial capacity. Moreover, the first discharge capacity reaches 3750 mAh g−1 and its specific capacity can still maintain 676 mAh g−1 after 100 cycles. Owing to this core–shell structure nanomaterial which provides more stable intercalation–deintercalation of lithium channels and sites, PPy coating can inhibit the volumetric expansion of the SnO2 nanospheres (NPs) electrode effectively. Consideration of the remarkable performance and high initial capacity, PPy/SnO2@SiO2 composite is of keen interest for a potential lithium ion battery anode material.

As a typical transition metal oxide anode material, ZnMoO4 can deliver a higher theoretical capacity of 951.6 mAh g−1 due to its variable oxidation state and alloying reaction. However, lower conductivity and huge volumetric expansion restrict its further development. Herein, the modified sol–gel method is applied to synthesize a series of (1-x)ZnMoO4-xZnFe2O4 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) composites. The effects of compound proportion of ZnFe2O4 on the crystal phase structure and morphology for ZnMoO4 have been investigated in detail. All the composites have been conducted on electrochemical measurements, and the results illustrate that the composites display better electrochemical performance than that of ZnMoO4. Especially for 0.6ZnMoO4-0.4ZnFe2O4, it can deliver a capacity of 550.7 mAh g−1 after 500 cycles at a current density of 200 mA g−1. Moreover, it also presents the higher capacity at higher current density. The improvement of electrochemical performance should be attributed to the synergistic effect of ZnFe2O4 and ZnMoO4.

During the past decades, lithium-sulfur batteries have obtained great attention due to their advantages as energy storage systems, which have high specific capacity and energy density. However, the real applications were hindered by many challenges, especially the shuttle effect of the polysulfide from the cathode to the anode side. This is attributed that the traditional PP films could not prevent the polysulfide migration from the cathode to the anode side. Therefore, it is an efficient method to develop a modified film, which could inhibit the polysulfide shuttle effect. Based on this idea, we prepared molybdenum sulfide–modified (MS modified) film as separators in the lithium-sulfur batteries, which were obtained by coating the molybdenum sulfide on the surface of the traditional PP films. The electrochemical results indicate that the Li–S battery by using MS–modified films exhibits excellent electrochemical performance.

The work discusses about the synthesis of indium-alizarin red S complex followed by its application toward the sensing of F¯ ion. At first, the interaction between indium and alizarin red S dye was studied at three different pH medium, pH 4, 7 and 9, of which pH 7 gave the best result. The indium-alizarin red S complex so obtained was then utilized for the ratiometric sensing of fluoride ion using absorption spectroscopy with variation of temperature. The lowest limit of detection (0.040 mM) was obtained at 313 K. The mechanism for the sensing of F¯ ion was then investigated using isothermal titration calorimetry. The endothermic nature of the interaction between F¯ ion with indium-alizarin red S complex shows temperature dependence on the sensing experiment. At the end, the utility of the technique toward natural sample was also examined. The present work reports a simple, rapid and efficient detection of fluoride anion in environmental water samples.

Surface damage produced by single MeV-GeV heavy ions impacting ultrathin polymer films has been shown to be weaker than those observed under bulk (thick film) conditions. The decrease in damage efficiency has been attributed to the suppression of long-range effects arising from excited atoms lying deeply in the solid. This raises the possibility that the substrate of the films itself may be relevant to the radiation effects seen at the top surface. Here, the role of the substrate on cratering induced by individual 1.1 GeV Au ions in ultrathin poly(methyl methacrylate) (PMMA) layers is investigated. Materials of different thermal and electrical properties (Si, SiO2, and Au) are used as substrates to deposit PMMA thin films of various thicknesses from ∼1 to ∼300 nm. We show that in films thinner than ∼40 nm craters are modulated by the underlying substrate to a degree that depends on the transport properties of the medium. Crater size in ultrathin films deposited on the insulating SiO2 is larger than in similar films deposited on the conducting Au layer. This is consistent with an inefficient coupling of the electronic excitation energy to the atomic cores in metals. On the other hand, the damage on films deposited on SiO2 is not very different from the Si substrate with a native oxide layer, suggesting, in addition, poor energy transmission across the film/substrate interface. The experimental observations are also compared to calculations from an analytical model based on energy addition and transport from the excited ion track, which describe only partially the results.

UvrD, a model for non-hexameric Superfamily 1 helicases, utilizes ATP hydrolysis to translocate stepwise along single-stranded DNA and unwind the duplex. Previous estimates of its step size have been indirect, and a consensus on its stepping mechanism is lacking. To dissect the mechanism underlying DNA unwinding, we use optical tweezers to measure directly the stepping behavior of UvrD as it processes a DNA hairpin and show that UvrD exhibits a variable step size averaging ~3 base pairs. Analyzing stepping kinetics across ATP reveals the type and number of catalytic events that occur with different step sizes. These single-molecule data reveal a mechanism in which UvrD moves one base pair at a time but sequesters the nascent single strands, releasing them non-uniformly after a variable number of catalytic cycles. Molecular dynamics simulations point to a structural basis for this behavior, identifying the protein-DNA interactions responsible for strand sequestration. Based on structural and sequence alignment data, we propose that this stepping mechanism may be conserved among other non-hexameric helicases., UvrD is a model helicase from the non-hexameric Superfamily 1. Here, the authors use optical tweezers to measure directly the stepwise translocation of UvrD along a DNA hairpin, and propose a mechanism in which UvrD moves one base pair at a time, but sequesters the nascent single strands, releasing them after a variable number of ATP hydrolysis cycles.

Combination treatment with BRAF (BRAFi) plus MEK inhibitors (MEKi) has demonstrated survival benefit in patients with advanced melanoma harboring activating BRAF mutations. Previous preclinical studies suggested that an intermittent dosing of these drugs could delay the emergence of resistance. Contrary to expectations, the first published phase 2 randomized study comparing continuous versus intermittent schedule of dabrafenib (BRAFi) plus trametinib (MEKi) demonstrated a detrimental effect of the “on−off” schedule. Here we report confirmatory data from the Phase II randomized open-label clinical trial comparing the antitumoral activity of the standard schedule versus an intermittent combination of vemurafenib (BRAFi) plus cobimetinib (MEKi) in advanced BRAF mutant melanoma patients (NCT02583516). The trial did not meet its primary endpoint of progression free survival (PFS) improvement. Our results show that the antitumor activity of the experimental intermittent schedule of vemurafenib plus cobimetinib is not superior to the standard continuous schedule. Detection of BRAF mutation in cell free tumor DNA has prognostic value for survival and its dynamics has an excellent correlation with clinical response, but not with progression. NGS analysis demonstrated de novo mutations in resistant cases., Whether intermittent strategies of delivering drugs can improve cancer patients survival is still unclear. Here, the authors reports the results of a randomized phase II clinical trial aimed to compare the efficacy and safety of two dosing regimens (continuous and intermittent) of vemurafenib and cobimetinib combination as first-line treatment of patients with unresectable or metastatic advanced melanoma with BRAFV600 mutation

Steviol glycosides are the intensely sweet components of extracts from Stevia rebaudiana. These molecules comprise an invariant steviol aglycone decorated with variable glycans and could widely serve as a low-calorie sweetener. However, the most desirable steviol glycosides Reb D and Reb M, devoid of unpleasant aftertaste, are naturally produced only in trace amounts due to low levels of specific β (1–2) glucosylation in Stevia. Here, we report the biochemical and structural characterization of OsUGT91C1, a glycosyltransferase from Oryza sativa, which is efficient at catalyzing β (1–2) glucosylation. The enzyme’s ability to bind steviol glycoside substrate in three modes underlies its flexibility to catalyze β (1–2) glucosylation in two distinct orientations as well as β (1–6) glucosylation. Guided by the structural insights, we engineer this enzyme to enhance the desirable β (1–2) glucosylation, eliminate β (1–6) glucosylation, and obtain a promising catalyst for the industrial production of naturally rare but palatable steviol glycosides., Steviol glycosides from the plant Stevia rebaudiana are already used as lowcalorie sweeteners, but the most abundant naturally occurring compounds have a bitter aftertaste. Here, the authors characterize and engineer rice glycosyltransferase OsUGT91C1 to facilitate the large-scale production of naturally rare but palatable glycosides Reb D and Reb M

In this research, a novel thin film Si-GO10 and nanopowders Si-GO30 of silica-graphene oxide (GO) composite were prepared via the sol–gel method and deposited on glass substrates using spray pyrolysis. X-ray diffraction (XRD) results showed a relatively strong peak in the graphite layer that corresponds to the (002) plane. Transmission electron microscope (TEM) images showed that SiO2 nanoparticles were randomly distributed on the surface of GO plates, and the particle size in these nanopowders was below 50 nm. Field emission scanning electron microscopy (FESEM) analysis demonstrated that silica nanoparticles on the surface of GO plates exhibited almost spherical and rod-like nanoparticle shape, which in turn confirmed the formation of SiO2–GO nano-hybrids. Photocatalytic investigations revealed that the composite materials exhibit high activity for dye adsorption and decomposition. Si-GO10 thin film did not undergo degradation after 120 min; however, for Si-GO30 nanopowder, the adsorption peak intensity was reduced to 665 nm, indicating a decrease in the dye concentration in the solution. Fourier transform infrared scan (FTIR) analysis demonstrated that carboxylic functional groups are decreased by increasing silica particles. Photoluminescence (PL) spectrum in Si-GO10 thin film showed a sharp emission peak at about 665 nm. This spectrum completely disappeared in Si-GO30 nanopowders. Results of the antibacterial properties emphasized that Si-GO30 nanoparticle would prevent Escherichia coli growth after 20 h. The presented methodology allows for the synthesis of GO supported silicon dioxide nanoparticles for promising applications in photocatalytic and antibacterial fields.