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[Display omitted] • Flammability limits of the new binary mixture R1234ze(E)/R32 was measured. • Oxidative decomposition and interaction mechanisms of R234ze(E)/R32 were studied. • R32 decomposes preferentially and R1234ze(E) is more likely to react with radicals. • CF 3 plays an important role in R1234ze(E) inhibiting flammability of R32. At present, mixed working fluids have received increasing attention due to their excellent comprehensive performance. Among them, R1234ze(E) (trans -1,3,3,3-tetrafluoropropene) and the R32 (difluoromethane) with excellent thermal properties can form a safe and environmentally friendly new mixture through advantageous complementarity. In this paper, the flammability of the binary mixture R1234ze(E)/R32 mentioned above was studied. Firstly, the flammability limits and critical concentration inhibition ratio of R1234ze(E)/R32 were tested at different ratios. Then, based on density functional theory (DFT), the interaction mechanism between the two components in the mixture was analyzed. The results show that with the increase of R1234ze(E), the flammable limit range becomes narrower. In the early stage of the reaction between R1234ze(E)/R32, R32 preferentially breaks the bond to generate H and F radicals, but the reactions between R1234ze(E) and free radicals are dominant. CF 3 radical is an important free radical for R1234ze(E) to inhibit the flammability of R32. The research results will have guiding significance for the internal interaction mechanism of the flammability of new binary mixtures and their safe applications. [ABSTRACT FROM AUTHOR]

The burning velocity plays an important role in determining the safety level of new refrigerants. Based on the self-designed test system for burning velocity characteristics of flammable refrigerants, the burning velocities of R152a with different concentration were studied by vertical glass tube method. And the maximum burning velocity of R152a was analyzed, which was close to the standard recommended value. R1234yf with environmental advantages and lower flammability may form a new alternative refrigerant mixture with R152a. Therefore, the flame propagation and burning velocity characteristics of R152a+R1234yf were studied under the conditions of different component ratio and different concentration. Based on the theoretical analysis, three calculation methods for predicting the burning velocity of binary mixed flammable refrigerant were proposed for the first time. Then, three groups of predicted burning velocity of R152a+R1234yf under different composition or concentrations were calculated. Compared with the experimental data, it was found that the prediction accuracy of the component equivalent simplified method is the highest among the three methods. It was of great significance for the prediction of burning velocity and the assessment of safety level of new mixed refrigerant or flammable gas. [ABSTRACT FROM AUTHOR]

High global warming potential (GWP) refrigerants for refrigeration and heat pump systems or organic Rankine cycle systems are being phased out because of their impact on climate change, such as R134a, R410A and R404A. So it is urgent to find the refrigerants with excellent environmental protection performance. Firstly, nearly 40 alternative refrigerants, including pure refrigerants and mixed refrigerants, are classified according to their environmental and safety characteristics. Secondly, the performance parameters of some typical alternatives, such as refrigerating capacity, COP, safety and environmental protection, are comprehensively compared. It can be concluded that R513a and R466A have good comprehensive performance as alternative refrigerants of R134a and R410A respectively, while those alternatives to R404A have both advantages and disadvantages. The application and technical characteristics of R32, some typical HFOs, natural refrigerants and mixtures are summarized and analyzed. In addition, our group has carried out experimental and theoretical research on the flammability of low GWP and flammable refrigerants such as R1234yf, R161, R290, R600a and R1150, and found that hydrocarbons are more difficult to be inhibited than halogenated hydrocarbons. Finally, a new research idea on the risk of refrigerant explosion is put forward, which can cover the refrigerant leakage, combustion and risk aversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flammability limits of R600a/R1234ze(E) and R600a/R1233zd(E) were obtained. • Critical (F + Cl)/H ratio for reducing the flammability limit range of HFOs mixtures. • Cl in halogenated olefins has a stronger inhibitory effect than F. • Under oxygen rich conditions, R1234ze(E) may promote the combustion of R600a. To reduce the greenhouse effect, environmentally friendly working fluids such as unsaturated halogenated olefins and hydrocarbons have attracted much attention. This study focuses on the combustion characteristics of two binary mixtures of isobutane (R600a) and R1234ze(E) and R1233zd(E). The results indicate that the addition of R1234ze(E) and R1233zd(E) has different effects on the combustibility of R600a under rich and lean fuel conditions. From the perspective of flammability limit range, as the ratio of R1234ze(E) and R1233zd(E) increases, the flammability limit range of both mixtures first increases and then decreases. For R1233zd(E)/R600a containing chlorine (Cl), the maximum flammable limit range corresponds to (n F + n Cl)/n H equal to 1/3, which is significantly smaller than the n F /n H ratio of 1 in R1234ze(E)/R600a. Secondly, through calculation and simulation, it was found that the flame retardancy of R1233zd(E) is stronger than that of R1234ze(E), as the Cl in the former has a stronger ability to capture active radicals. Finally, based on Chemical kinetics analysis, it is found that adding R1234ze(E) to R600a during oxygen enrichment will increase the concentration of active radicals H, O and OH during combustion. This leads to higher combustion temperature and smaller flame thickness, thereby promoting the combustion process. The results will have significant implications for the safe application of new mixed working fluids and the analysis of internal reaction mechanisms of the mixture flammability. [ABSTRACT FROM AUTHOR]

• Inhibitory effects of R13I1 and N 2 on flammability of R1234yf were studied. • A comprehensive evaluation parameter of inhibition characteristic was proposed. • A schematic diagram was proposed to analyze GWP and FL of binary mixtures. • A brief mechanism for chemical inhibition of flame retardants was analyzed. R1234yf has attracted wide attention because of its excellent environmental protection performance. However, the potential flammability hazards of R1234yf will affect its use and promotion. This article will focus on the flammability changes of R1234yf before and after adding different flame retardants. Firstly, the flammability limits of the mixtures of R1234yf+R13I1 and R1234yf+N 2 were tested out. And the critical suppression ratios of the two flame retardants/R1234yf were obtained by analyzing the experimental data. The chemical inhibition mechanism of R13I1 to R1234yf was analyzed, and a brief mechanism for chemical inhibition of flame retardants was obtained from two stages. Then, in order to more reasonably determine the inhibiting characteristics of flame retardants to flammable refrigerants, a method for evaluating the inhibition properties of flame retardants with three parameters was proposed, including critical suppression ratio, flammability limits range, and inhibition efficiency. And the inhibition characteristics of four flame retardants R13I1, N 2 , R134a and R227ea on R1234yf were obtained, respectively. Finally, the global warming potential and flammability limits (or critical suppression ratios) of three mixtures were compared based on a new two-coordinate schematic diagram, which can comprehensively compare the environmental protection and safety of binary mixtures. The results will provide references for reducing the combustibility hazards of R1234yf and searching for new refrigerants. [ABSTRACT FROM AUTHOR]

• The effects of crystalline structure on the thermal conductivity of PE are studied. • Microscale mechanisms due to structure transition are explored by MD simulations. • The thermal conductivity of PE is reduced by a half after the α-to-γ phase change. • Strong intermolecular HBs break off and form weaker HBs during the phase change. • The distinguished heat transfer capability of HBs is calculated and demonstrated. A typical polyol that experiences solid-solid phase transitions, pentaerythritol (PE) has been proposed as a promising phase change material candidate for latent heat storage pertinent to the temperature range for industrial waste heat recovery. Upon increasing the temperature to over the solid-solid phase transition point (∼459 K), body-centered tetragonal crystalline structure of PE (α phase) is transformed into orientationally disordered face-centered cubic crystalline structure (γ phase). The thermal conductivity of PE at both α and γ phases is of great practical interest. In this work, the in situ X-ray diffraction and Fourier transformer infrared spectroscopy were used to characterize the crystalline structure transition of PE, in combination with the differential scanning calorimetry results. Molecular dynamics simulations were performed to elucidate the relationship between the thermal conductivity variation of PE and its crystalline structures at the atomic level. It was found that after the α-to-γ phase transition, the rearrangement and rotation of the O H···O bonds lead to indeterminate positions of the O and H atoms in the γ phase. The destruction and weakening of the hydrogen bonds can be the major change in the crystalline structures, leading to the reduction of the thermal conductivity of PE by a half after the α-to-γ phase transition. [ABSTRACT FROM AUTHOR]

Abstract Combined three-dimensional plastic flow and strain-induced phase transformation (PT) in boron nitride (BN) under high pressure and large shear in a rotational diamond anvil cell (rotational DAC or RDAC) are investigated. Geometrically nonlinear frameworks including finite elastic, transformational, and plastic deformations and finite element method (FEM) are utilized. Quantitative information is obtained on the evolutions of the stress tensor, plastic strain, volume fraction of phases in the entire sample, and slip-cohesion transitions, all during torsion under a fixed compressive load in RDAC. The effects of the applied compressive stress and the sample radius on PT and plastic flow are discussed. In comparison with DAC, the same amount of the high-pressure phase can be obtained at a much lower pressure in RDAC, which reduces the required force and the risk of diamond fracture. Also, RDAC has a potential to complete PT during torsion under pressure close to the minimum possible. A quasi-homogeneous pressure can be obtained in a transforming sample in RDAC under a proper choice of properties and parameters of a gasket. A number of experimental phenomena, including the pressure self-multiplication and quasi-homogeneous pressures in DAC and RDAC, are reproduced and interpreted. The simulation results provide a significant insight into coupled PTs and plastic flow in material in RDAC, and are important for the optimum design of experiments and the extraction of material parameters for PT, as well as for the optimization and control of PTs by the variation of various parameters. Highlights • Model with large plastic strains and phase transformation in rotational diamond anvils is presented. • Strain-induced phase transformation in boron nitride under compression and torsion is studied. • Results in traditional and rotational diamond anvil cells are compared. • Pressure self-multiplication and quasi-homogeneous pressures in experiment are reproduced. [ABSTRACT FROM AUTHOR]

Abstract The continuous synthesis of geranyl butyrate in organic solvent was studied. The Candida rugosa lipase(CRL) was firstly immobilized on weak-acidic macroporous cation exchange resin D151. The batch experiments indicated that the adequate acid/alcohol molar ratio was 1:1.5 and the reaction time was 3.5–4 h. Then the continuous synthesis was realized with immobilized Candida rugosa lipase in a circulating fluidized bed reactor(CFBR). A stable ester yield of 77% was achieved under optimal conditions: enzyme loading 8 g, expansion ratio 1.6, feed flow rate 0.07 ml/min and butyric acid concentration 75 mmol/l. The results provide the basis for the scale-up of the process. [ABSTRACT FROM AUTHOR]

MXenes are considered as an emerging class of two-dimensional (2D) adsorbent for various environmental applications. In this work, two different morphologies of Ti 3 C 2 T x MXene (multilayer (ML-Ti 3 C 2 T x) and delaminated titanium carbide (DL-Ti 3 C 2 T x)) were prepared through mild in situ HF etching and further delamination. The structural differences between the two were explored with a focus on their effects on the performance and mechanism of removing heavy metals from water. In comparison to ML-Ti 3 C 2 T x , DL-Ti 3 C 2 T x had more oxygen-containing functional groups, higher specific surface area (19.713 vs. 8.243 m2/g), larger pore volume (0.135 vs. 0.040 cm3/g), higher maximum Pb(II) adsorption capacity (77.0 vs. 56.68 mg/g), but lower maximum Cu(II) adsorption capacity (23.08 vs. 55.46 mg/g). Further investigation revealed that the removal of Pb(II) by the MXenes was mainly controlled through electrostatic attraction and surface complexation mechanisms, while Cu(II) was removed mainly through surface reduction by Ti-related groups. Because delamination of ML-Ti 3 C 2 T x increased the surface area and surface functional groups, DL-Ti 3 C 2 T x became a better sorbent for Pb(II) in water. During sonication, however, delamination inevitably led to partial oxidation of Ti 3 C 2 T x nanosheets and thus weakened the reducing ability of DL-Ti 3 C 2 T x for Cu(II) in water. Nevertheless, both ML- and DL-Ti 3 C 2 T x not only exhibited excellent heavy metal adsorption capacity under different solution conditions, but also showed good reusability. Findings of this study indicate that Ti 3 C 2 T x MXenes are promising adsorbents for treating heavy metal pollutants in water. [Display omitted] • Multilayer and delaminated Ti 3 C 2 T x showd great potential in removing heavy metals. • Delamination raised the surface area of Ti 3 C 2 T x , enhancing Pb(II) adsorption. • Delamination oxidized Ti 3 C 2 T x nanosheets, reducing their Cu(II) reduction ability. [ABSTRACT FROM AUTHOR]

R1234yf has been considered as an alternative refrigerant with the low global warming potential (GWP), but it is flammable. Therefore, it is necessary to study the reduction or inhibition of flammability of R1234yf by different flame retardants. This paper mainly contributed to the influence of two kinds of flame retardants on the flammability of R1234yf. Firstly, the flammability limits of R1234yf and the mixtures of R1234yf/R227ea and R1234yf/R134a were tested out. Then the relationship between their flammability limits characteristics with the ratio of the flame retardants to R1234yf were evaluated by the fitted equations. The critical suppression ratios of R227ea/R1234yf and R134a/R1234yf were obtained. The results indicated that the inhibitory effect of R227ea on R1234yf was better than that of R134a by comparative analysis. Finally, the flame colors and flame propagation velocity characteristics of R1234yf before and after the addition flame retardants were researched and analyzed. The research achievement will be of universal guiding significance for the security application of R1234yf. [ABSTRACT FROM AUTHOR]

• The dynamic performances of a compressed CO 2 energy storage (CCES) system were evaluated. • The dynamic model was validated using experimental data. • The dynamic round-trip efficiency of the CCES system varies in the range 16.7% − 56.7%. • The RTE obtained from the steady-state model is higher 23.9% than value from the dynamic model. For the first time, the study investigated the dynamic performances of a compressed CO 2 energy storage (CCES) system based on a dynamic model, which was validated using experimental data. The dynamic round-trip efficiency (RTE) of a scaled-up CCES system in two typical operation modes was studied, including Mode 1: the basic operation mode, where the inlet pressure of the compressor or the expander is not controlled, and Mode 2: the controlled operation mode, where the capacity for compression or expansion is regulated to remain constant. Dynamic RTE varies in the range 16.7%-56.7% in various operation modes. A new key performance indicator, utilization of tank (UOT), was defined to reflect how much working gas is used in a charging or a discharging process. In general, high charging and high discharging capacities lead to low UOTs and low RTEs. Moreover, the comparison between the dynamic model and its equivalent steady-state model showed a significant difference in system performances. The RTE of the steady-state model reaches 68.5%, which is much higher than the corresponding dynamic RTE of 55.3%. [ABSTRACT FROM AUTHOR]

In order to study high-pressure phase transformations (PTs), high static pressure is produced by compressing a thin sample within a high strength gasket in a diamond anvil cell (DAC). However, since a PT occurs during plastic flow, it is classified and treated here as a plastic strain-induced PT. A thermodynamically consistent system of equations for combined plastic flow and plastic strain-induced PTs is formulated for large elastic, plastic, and transformation strains. The Murnaghan elasticity law, pressure-dependent J 2 plasticity (both dependent of the concentration of a high-pressure phase), and plastic strain-induced and pressure-dependent PT kinetics are utilized. A computational algorithm within finite element method (FEM) is presented and implemented in a user material subroutine (UMAT) in the FEM code ABAQUS. Combined plastic flow and strain-induced PT from the highly-disordered hexagonal boron nitride (hBN) sample to a superhard wurtzitic wBN is simulated within the rhenium gasket for pressures up to 50 GPa. The evolution of the fields of stresses and plastic strains, as well as the concentration of phases in a sample is obtained and discussed in detail. Stress-strain fields in a gasket and diamond are presented as well. An unexpected shape of the deformed sample with almost complete PT in the external part of the sample that penetrated the gasket was found. Obtained results demonstrated the difference between material and system behavior which are often confused by experimentalists. Thus, while plastic strain-induced PT may start (and end) at plastic straining slightly above 6.7 GPa, it is not visible below 12 GPa. It becomes detectable at 21 GPa and is not completed everywhere in a sample even at a maximum pressure of 50 GPa. Due to a strong gasket the gradient of pressure is much smaller than the gradient of plastic strain, and therefore the distribution of the high pressure phase is mostly determined by the plastic strain field instead of the pressure field. Possible misinterpretation of the experimental data and characterization of the PT is discussed. The developed model will allow computational design of experiments for synthesis of high-pressure phases. [ABSTRACT FROM AUTHOR]

Material behavior under high pressure and large plastic shear is usually studied in a rotational diamond anvil cell (rotational DAC, or RDAC). The first modeling results for three-dimensional plastic flow and evolution of the stress-strain state for a rhenium sample compressed and twisted in RDAC under megabar pressures are presented. Large elastic and plastic deformation theory is utilized. In addition to quantitative information about evolution of the stress-strain fields, the following unexpected results are obtained. During initial compression followed by torsion under a fixed axial force and for beveled anvils, the sample thickness reduces by a factor of ninety. Pressure, as well as the pressure gradient, grow drastically at the central part, and this new phenomenon is called the pressure self-focusing effect. This effect allows a much higher maximum pressure to be reached in a RDAC than in a DAC under the same force. The effects of diamond and sample shape, yield strength and its pressure dependence, the friction coefficient, and applied force on the pressure distribution are analyzed. The obtained results open new ways to increase maximum achievable pressure and develop new intuition in mechanical responses at megabar pressures which will be beneficial to the optimum design of geometry and loading conditions in the experiment. [ABSTRACT FROM AUTHOR]

Fluorine-containing refrigerants will still play an irreplaceable role in the process of research and development of new refrigerants. So it is critical to study the main toxic combustion product HF. This paper contributed to concentration characteristics of HF about R32 and R161 on particular concentrations when combustion reaction occurred. Firstly, a new enclosed test method of concentration of HF (C HF ) was presented through comparative analysis different existent methods and results. Then based on the original experimental system independently designed and built, actual C HF of 16.9%/16.89% R32 and 4.17%–4.74% R161 were measured respectively under the conditions of normal temperature and humidity. Moreover, an equation was obtained to estimate the relationship between the actual C HF and concentration of R161 (C R161 ), when C R161 was in the range of lower flammability limit (LFL) and stoichiometric concentration (C st ). And the possible affected factors of the actual C HF were analyzed. Finally it should be given sufficient attention that the risk of high C HF still exists. Therefore, the results will be of universal guiding significance for the security application of fluorine-containing refrigerants in this paper. [ABSTRACT FROM AUTHOR]

Coupled plastic flows and the strain-induced α → ω phase transformation (PT) in a zirconium sample under compression in a diamond anvil cell are investigated using finite element method (FEM). The PT is treated as strain-induced rather than pressure-induced and the previously developed model for strain-induced PTs is utilized. Very heterogeneous fields of stress tensor, accumulated plastic strain, and concentration of the ω phase are obtained for different applied loads. The PT starts at the center of a sample when pressure exceeds the minimum pressure p ε d = 1.7 G P a , below which a direct strain-induced PT to a high pressure phase cannot occur, and it propagates from the center to the periphery with an increasing load. Even at the maximum pressure of 7 GPa, the PT is not completed everywhere. With an increasing load, the pressure and pressure gradient along the radial direction significantly increase in the two-phase region due to the much larger yield strength of the ω phase. This in turn promotes transformation and produces a positive mechanochemical feedback. Obtained results are utilized for the interpretation of published experimental data on pressure-, stress-, and strain-induced α → ω PTs in Zr and Titanium (Ti) and α → β and ω → β PTs in Zr under compression and high pressure torsion. This includes correcting the reported minimum pressures for these transformations by a factor of 3–6 due to the stress heterogeneity, the effect of transmitting media, the pressure hysteresis, and the reversibility of the transformation. [ABSTRACT FROM AUTHOR]

In high pressure research, static megabar pressures are typically produced by compression of a thin sample by two diamonds in various types of diamond anvil cells. This process is accompanied by large plastic deformation (sample thickness is reduced by a factor of 30), and finite elastic deformation of a sample and even the diamond. A thermodynamically consistent system of equations for large elastic and plastic deformation of an isotropic material obeying nonlinear elasticity and pressure dependent yield condition is formulated. The Murnaghan elasticity law and pressure-dependent J 2 plasticity are utilized. The finite-strain third-order elasticity law for cubic crystals is utilized for diamond. A computational algorithm is presented with emphasis on the stress update procedure and derivation of the consistent tangent moduli. It is implemented as a user material subroutine in the finite element code ABAQUS. Material parameters for a rhenium sample, as an example, and a diamond are calibrated based on the experimental and atomistic simulation results in the literature. The evolution of the stress and strain tensor fields in the sample and diamond is studied up to a pressure of 300 GPa. Good correspondence between numerical and experimental pressure distributions at the diamond-sample contact surface is obtained. Because there is a significant scatter of the magnitude of reported third-order single-crystal elastic moduli for diamond, their effect on strains and stresses is studied in detail. With the smaller third-order elastic moduli, the phenomenon of cupping of the diamond-sample contact surface is reproduced, which plays an important role in increasing maximum pressures for a given anvil geometry. The results provide important insight into the mechanical response in diamond anvil cells, interpretation of materials properties under extreme conditions from heterogeneous fields, and optimum design of cells for reaching the maximum static pressure in a volume sufficient for the desired measurements. [ABSTRACT FROM AUTHOR]

This study guided the potential of composite phospholipid-chitosan vesicles (chitosomes) as novel delivery systems for four kinds of carotenoids, lycopene, β-carotene, lutein and canthaxanthin. Chitosomes were successfully achieved by combing the liposomal preparation and the layer self-assembly deposition technique. The physical properties of such colloidal nanocarriers were characterized by microstructure, particle size and distribution using transmission electron microscopy and dynamic light scattering. It was demonstrated that chitosan can flatly adsorb onto the membrane surface through electrostatic attraction, inducing charge inversion but maintaining the spherical shape of liposomes. Fluorescence polarization analysis revealed that the interaction of chitosan with liposomal membrane, such as electrostatic and hydrophobic interaction, restricted the motion freedom of lipid molecules and enhanced their ordering at the polar headgroup region and hydrophobic core of the membrane. These rigidifying effects were directly response for the stabilization of carotenoid-loaded liposomes against heating, gastrointestinal stress and centrifugal sedimentation. In addition, the encapsulating and retaining ability of chitosomes highly depended on the molecular structures of carotenoids. That is, the liposomal membrane was able to protect β-carotene and lutein to a higher level than lycopene and canthaxanthin. These results may contribute to the development of chitosomes as potential candidates for an efficient delivery of bioactive compounds in nutraceutical and functional foods. [ABSTRACT FROM AUTHOR]

Aims MicroRNAs (miRNAs) play important roles in several biological processes. In this study, we investigated the role of miR-1, an endothelin-1 (ET-1) targeting miRNA, in endothelial cells (ECs) and tissues of diabetic animals. ET-1 is known to be of pathogenetic significance in several chronic diabetic complications. Main methods PCR array was used to identify alterations of miRNA expression in ECs exposed to glucose. miR-1 expression was validated by TaqMan real-time PCR assay. Human retinal ECs (HRECs) and human umbilical vein ECs (HUVECs) exposed to various glucose levels with or without miR-1 mimic transfection, and tissues from streptozotocin-induced diabetic animals after two months of follow-up, were examined for miR-1 expression, as well as ET-1 and fibronectin (FN) mRNA and protein levels. Key findings Array analyses showed glucose-induced alterations of 125 miRNAs (out of 381) in ECs exposed to 25 mM glucose compared to 5 mM glucose. Fifty-one miRNAs were upregulated and 74 were downregulated. 25 mM glucose decreased miR-1 expression and increased ET-1 mRNA and protein levels. miR-1 mimic transfection prevented HG-induced ET-1 upregulation. Furthermore, glucose induced upregulation of FN, which is mediated partly by ET-1, was also prevented by such transfection. Diabetic animals showed decreased miR-1 expression in the retina, heart and kidneys. In parallel, ET-1 mRNA expressions were increased in these tissues of diabetic animals, in association with upregulation of FN. Significance These results indicate a novel glucose-induced mechanism of tissue damage, in which miR-1 regulates ET-1 expressions in diabetes. Identifying such mechanisms may lead to RNA based treatment for diabetic complications. [ABSTRACT FROM AUTHOR]

Modular electrochemical production (MEP) system could decouple the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and pairing with a redox mediator (RM), respectively. Herein, Mott–Schottky Co 9 S 8 /Ni 3 S 2 heterojunction was constructed, which was employed as a RM to separate the hydrogen and oxygen production in space and time in MEP system for H 2. The MEP system for H 2 involved a two−step electrochemical−electrochemical (EC−EC) looping process. The reversible redox reaction of Co 9 S 8 /Ni 3 S 2 was paired with HER in step 1 and subsequently paired with OER in step 2. The Mott–Schottky hetero-structures enabled the redistribution of Ni central charge and accelerated the electron transfer from semiconductor Ni 3 S 2 to metallic Co 9 S 8 on the interface. This made the formation of Lewis acid at the Ni 3 S 2 in the heterojunction, which bonded with the OH− Lewis base, facilitating the electrochemical redox kinetics of Co 9 S 8 /Ni 3 S 2. Thus, the Co 9 S 8 /Ni 3 S 2 RM presented a high area capacitance (29.60 F/cm2 at 5 mA/cm2), and an excellent stability upon operation over 5000 cycles (15 days). The MEP system can continuously produce H 2 for 1502 s at 10 mA/cm2 with a Faradaic efficiency of 100%. The MEP system possessed a high energy efficiency (83%), requiring a lower cell voltage than that of a conventional water electrolysis system. The MEP system for H 2 enabled flexible utilization of renewable solar energy by photovoltaic (PV) panels, thereby facilitating solar-to-hydrogen conversion. [Display omitted] • Charge redistribution facilitates redox kinetics of Mott–Schottky Co 9 S 8 /Ni 3 S 2. • H 2 and O 2 are separated in time and space avoiding gas mixing and purification. • The MEP system shows high energy efficiency (80%) at 10 mA/cm2. • Modular PV-water electrolysis system provides a promising strategy for conversion of solar to H 2. [ABSTRACT FROM AUTHOR]

Abstract: Aims: MicroRNAs (miRNAs) play important roles in several biological processes. In this study, we investigated the role of miR-1, an endothelin-1 (ET-1) targeting miRNA, in endothelial cells (ECs) and tissues of diabetic animals. ET-1 is known to be of pathogenetic significance in several chronic diabetic complications. Main methods: PCR array was used to identify alterations of miRNA expression in ECs exposed to glucose. miR-1 expression was validated by TaqMan real-time PCR assay. Human retinal ECs (HRECs) and human umbilical vein ECs (HUVECs) exposed to various glucose levels with or without miR-1 mimic transfection, and tissues from streptozotocin-induced diabetic animals after two months of follow-up, were examined for miR-1 expression, as well as ET-1 and fibronectin (FN) mRNA and protein levels. Key findings: Array analyses showed glucose-induced alterations of 125 miRNAs (out of 381) in ECs exposed to 25mM glucose compared to 5mM glucose. Fifty-one miRNAs were upregulated and 74 were downregulated. 25mM glucose decreased miR-1 expression and increased ET-1 mRNA and protein levels. miR-1 mimic transfection prevented HG-induced ET-1 upregulation. Furthermore, glucose induced upregulation of FN, which is mediated partly by ET-1, was also prevented by such transfection. Diabetic animals showed decreased miR-1 expression in the retina, heart and kidneys. In parallel, ET-1 mRNA expressions were increased in these tissues of diabetic animals, in association with upregulation of FN. Significance: These results indicate a novel glucose-induced mechanism of tissue damage, in which miR-1 regulates ET-1 expressions in diabetes. Identifying such mechanisms may lead to RNA based treatment for diabetic complications. [Copyright &y& Elsevier]