A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo...A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.展开更多
The extensive use of polymeric materials in single-use packaging has driven the need to develop biodegradable alternatives.This study investigates the incorporation of graphene oxide(GO)and Moringa oleifera seed oil(M...The extensive use of polymeric materials in single-use packaging has driven the need to develop biodegradable alternatives.This study investigates the incorporation of graphene oxide(GO)and Moringa oleifera seed oil(MOSO)into a gelatin matrix to create polymer films and evaluate their potential as active packaging materials.The properties of these films were evaluated using structural,thermal,mechanical,optical,and physicochemical methods to determine their suitability for food packaging applications.The results showed that GO and MOSO were homogeneously dispersed in the gelatin matrix,forming colloidal particles(around 5μm in diameter).The addition of GO increased opacity by approximately 20 times the base value while MOSO affected light transmittance without impacting opacity.Mechanical properties were affected differently,GO acted as a crosslinking agent reducing elongation and increasing tensile strength at break,on the other hand MOSO acted as a plasticizer,making films more plastic increasing elongation a 30%.These effects counteracted each other,and similar behavior was recorded in differential scanning calorimetry.The films exhibited an improved water vapor resistance,which is crucial for food packaging.These findings indicate that the incorporation of GO and MOSO into a gelatin matrix may produce biodegradable polymer films with enhanced properties,suitable for active packaging in the food industry.展开更多
Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec...Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec tive products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties.Herein,we construct an efficient,concentrated sunlight-driven CO_(2)RR setup consisting of InGaP/GaAs/Ge triple-junction cell as a photoanode and oxide-derived Au(Ox-Au)as a cathode to perform the unassisted PEC CO_(2)RR.Under one-sun illumination,a maximum operating current density of 11.5 mA cm^(-2) with an impressive Faradaic efficiency(FE)of~98%is achieved for carbon monoxide(CO)production,leading to a solar-to-fuel conversion efficiency of~15%.Under concentrated intensity of 10 sun,the photoanode records a maximum current density of~124 mAcm^(-2) and maintains~60%of FE for CO production.The results demonstrate crucial advancements in usingⅢ-Ⅴbased photoanodes for concentrated PEC CO_(2)RR.展开更多
The first successful generation of induced pluripotent stem （iPS） cells from somatic cells was accomplished by introducing four genes into the cell, 0Ct3/4, Sox2, Klf4, and c-myc [1]. While a tour-de-force, this app...The first successful generation of induced pluripotent stem （iPS） cells from somatic cells was accomplished by introducing four genes into the cell, 0Ct3/4, Sox2, Klf4, and c-myc [1]. While a tour-de-force, this approach to iPS cell generation is inefficient, and unlikely to be directly translated into therapeutic use since it involves the use ofretroviruses to introduce these genes into the cell. Subsequent studies have used non-integrating genetic elements,展开更多
Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particle...Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.展开更多
Crude oil pollution in the Niger Delta, perpetrated by both local communities and industrial actors, has brought about soil pollution with its consequent ecological, human health and food challenges. The purpose of th...Crude oil pollution in the Niger Delta, perpetrated by both local communities and industrial actors, has brought about soil pollution with its consequent ecological, human health and food challenges. The purpose of this research was to examine the concentration and distribution of heavy metals in soil from communities contaminated by crude oil in Niger Delta, and to evaluate the potential health risks to residents from exposure to these contaminants. To achieve this, soil samples were collected from the Ihwrekreka community and analyzed for heavy metal content using inductively coupled plasma mass spectrometry (ICP-MS). The analytical results in mg/kg revealed a significant metals pollution level derived from the oil spill in the soil ranging from 4.85 - 17,078 (Cu), 1.01 - 16.1 (Cd), 0.22 - 36.8 (Cr), 8.28 - 40.9 (Ni), 7.51 - 6474 (Pb), and 8.84 - 12,851 (Zn) respectively. Most of the metals were above the permissible limits of World Health Organization, with Cu, Zn, and Pb as the most contaminating metals. Lead was found to be the main contributor to the hazard index (HI) values for both children and adults in the study area, with its concentration exceeding the permitted limits set by the WHO and the EC. The hazard index (HI) values of Pb, Cu, Zn, Cd, Ni, and Cr were significantly higher than 1. These findings suggest that the release of heavy metals from an oil-contaminated site may pose a risk to human health and the environment.展开更多
The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by...The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by BET, XRD (X-ray diffraction), TPR (temperature programmed reduction), IR (infra-red adsorption), NH 3-TPD (temperature programmed desorption) and CO 2-TPD (temperature programmed desorption) techniques. The results showed that the surface area of catalysts decreased with increasing metal content, and the metals as well as Cu-Ni alloy co-existed on the reduced catalyst surface. There existed interaction between metal and carrier, and moreover, metal particles affected obviously the acidity and basicity of carrier. The large amount of basic sites facilitated the activation of methanol to methoxyl species and their subsequent reaction with activated carbon dioxide. The catalysts were evaluated in a continuous tubular fixed-bed micro-gaseous reactor and the catalyst with bimetal loading of 20% (by mass) had best catalytic activities. Under the conditions of 393 K, 1.1 MPa, 5 h and gas space velocity of 510 h 1 , the selectivity and yield of DMC were higher than 86.0 % and 5.0 %, respectively.展开更多
A molecular imprinting polymer technique was successfully applied to precipitation polymerization by using styrene as a functional monomer, curcuminoids as templates, acetonitrile as a porogenic solvent,benzoyl peroxi...A molecular imprinting polymer technique was successfully applied to precipitation polymerization by using styrene as a functional monomer, curcuminoids as templates, acetonitrile as a porogenic solvent,benzoyl peroxide as the initiator, and ethylene glycol dimethacrylate as the crosslinker. The effects of interaction on the adsorption capacity of the molecularly imprinted polymer(MIP) and non-imprinted polymer(NIP) were investigated. A comparison of the adsorption capacity for MIP and NIP indicated that the NIP had the lowest adsorption capacity. The curcuminoid-imprinted polymer(Cur-MIP) was synthesized from 0.0237 mmol of styrene, 47.0 g of acetonitrile, 1.0238 mmol of ethylene glycol dimethacrylate, 0.0325 mmol of curcuminoids, and 0.2480 mmol of benzoyl peroxide. A high-performance liquid chromatography method with fluorescence detection was developed and validated for various chromatographic conditions for the determination of the curcuminoids in turmeric samples. The sample solution was separated using the Cur-MIP via solid-phase extraction and analyzed on a Brownlee analytical C_(18) column(150 mm ×6 mm, 5 mm) using an isocratic elution consisting of acetonitrile and 0.1%trichloroacetic acid(40:60, v/v). The flow rate was maintained at 1.5 m L/min. The fluorescence detector was set to monitor at λex? 426 nm and λem? 539 nm. The quantification limit values were found to be16.66, 66.66, and 33.33 mg/L for curcumin, demethoxycurcumin, and bisdemethoxycurcumin, respectively. Thus, we concluded that the Cur-MIP and high-performance liquid chromatographic-fluorescence method could be applied to selective extraction and could be used as a rapid tool for the determination of curcuminoids in medicinal herbal extracts.展开更多
Herein, we report the design and synthesis of three new D-A type metal-free carbazole based dyes（S1-3）as effective co-sensitizers for dye-sensitized solar cell（DSSC） sensitized with Ru（Ⅱ） complex（NCSU-10）.In ...Herein, we report the design and synthesis of three new D-A type metal-free carbazole based dyes（S1-3）as effective co-sensitizers for dye-sensitized solar cell（DSSC） sensitized with Ru（Ⅱ） complex（NCSU-10）.In this new design, the electron rich carbazole unit was attached to three different electron withdrawing/anchoring species, viz. 4-amino benzoic acid, sulfanilic acid and barbituric acid. The dyes were characterized by spectral, photophysical and electrochemical analysis. Their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of the structures of these co-sensitizers on the photovoltaic performances. Further, S1-3 dyes were co-sensitized along with a well-known NCSU-10 dye in order to broaden the spectral response of the co-sensitized devices and hence improve the efficiency. The photovoltaic performance studies indicated that, the device fabricated using S1 dye as co-sensitizer with 0.2 mM of NCSU-10 exhibited improved PCE of 9.55% with JSC of 22.85 mA cm-2, VOC of 0.672 V and FF of 62.2%, whereas the DSSC fabricated with dye NCSU-10（0.2 mM） alone displayed PCE of 8.25% with JSC of 20.41 mA cm-2, VOC of 0.667 V and FF of 60.6%. Furthermore, electronic excitations simulated using time-dependent DFT, were in good agreement with the experimentally obtained results of the co-sensitizers, indicating that the exchange-correlation function and basis set utilized for predicting the spectra of the co-sensitizers are quite appropriate for the calculations. In conclusion, the results showed the potential of simple organic co-sensitizers in the development of efficient DSSCs.展开更多
Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies, sedimentary provenance analysis and thickness distribution of the Mesozo...Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies, sedimentary provenance analysis and thickness distribution of the Mesozoic Ordos Basin, it is demonstrated that the depocenters migrated counterclockwise from southeast to the north and then to the southwest from the Middle-Late Triassic to the Early Cretaceous. There were no unified and larger-scale accumulation centers except several small isolated accumulation centers before the Early Cretaceous. The reasons why belts of relatively thick strata were well developed in the western basin in several stages are that this area is near the west boundary of the original Ordos Basin, there was abundant sediment supply and the hydrodynamic effect was strong. Therefore, they stand for local accumulation centers. Until the Early Cretaceous, depocenters, accumulation centers and subsidence centers were superposed as an entity in the southwest part of the Ordos Basin. Up to the end of the Middle Jurassic, there still appeared a paleogeographic and paleostructural higher-in-west and lower-in-east framework in the residual basin to the west of the Yellow River. The depocenters of the Ordos Basin from the Middle-Late Triassic to the Middle Jurassic were superposed consistently. The relatively high thermal maturation of Mesozoic and Paleozoic strata in the depocenters and their neighborhood suggest active deep effects in these areas. Generally, superposition of depocenters in several periods and their consistency with high thermal evolution areas reveal the control of subsidence processes. Therefore, depocenters may represent the positions of the subsidence centers. The subsidence centers （or depocenters） are located in the south of the large-scale cratonic Ordos Basin. This is associated with flexural subsidence of the foreland, resulting from the strong convergence and orogenic activity contemporaneous with the Qinling orogeny.展开更多
The Mo-promoted Cu-Fe bimetal catalysts were prepared and used for the formation of dimethyl carbonate （DMC） from CO2 and methanol. The catalysts were characterized by X-ray diffraction （XRD）, temperature programm...The Mo-promoted Cu-Fe bimetal catalysts were prepared and used for the formation of dimethyl carbonate （DMC） from CO2 and methanol. The catalysts were characterized by X-ray diffraction （XRD）, temperature programmed reduction （TPR）, laser Raman spectra （LRS）, energy dispersive spectroscopy （EDS） and temperature programmed desorption （TPD） techniques. The experimental results demonstrated that the Mo promoters can decrease the reducibility and increase the dispersion of Cu-Fe clusters, The concentration balance of base-acid sites can be readily adjusted by changing the Mo content. The moderate concentration balance of acid and base sites was in favor of the DMC formation, Under optimal experimental conditions, the highest methanol conversion of 6,99% with a DMC selectivity of 87.7% can be obtained when 2.5 wt% of Mo was loaded.展开更多
Cyanine dyes of zero/bis-zero methine incorporating imid-azo(1,2-a)Pyridine (quinoline) or pyrazino(1,2-a)pyridine (quinoline) with stable C-N bond were synthesized using keto-oxime methylene C-link heterocyclic quate...Cyanine dyes of zero/bis-zero methine incorporating imid-azo(1,2-a)Pyridine (quinoline) or pyrazino(1,2-a)pyridine (quinoline) with stable C-N bond were synthesized using keto-oxime methylene C-link heterocyclic quaternary salts [1-phenyl-3-methyl-pyrazolino-4-keto-oxime-α-methylene-bis-pyridin-(quinoin)-1(4)-di-ium-iodide(ethiodide) salts and 1-phenyl-3-methyl-pyrazolino- 4-ketooxime-α-methylene-N-2-methyl-bis pyridin (quinoin)-1(4)-di-ium-iodide(ethiodide) salts]. Such heterocyclic precursors and related dyes were identified by elemental and spectral analyses. The absorption spectra properties of such dyes were investigated in 95% Ethanol to attempt and throw some light on the influence of such new heterocyclic nuclei and to compare or evaluate spectral behaviors. The absorption spectra of dyes in different pure solvents were examined in the visible region showing solvatochromism and the colour changes of dyes with solvents having different polarities. This permits a selection of the optimal solvent (fractional solvent) when such dyes are applied as photosensitizers. The spectral behavior of some selected newly synthesized cyanine dyes is observed in mixed solvents of different polarities and progressively increasing quantities of one solvent over the other were studied and showed an increase in the absorbance of CT band with increasing proportion of that solvent. Evidence for hydrogen bond formation between the solute molecules and solvent molecules allows measurement of certain energies such as hydrogen bonding, orientation, and free energies.展开更多
Phosphate is a primary nutrient required for the normal functioning of many organisms in the ecosystem. However, presence of excess phosphate into the aquatic systems leads to eutrophication which can promote harmful ...Phosphate is a primary nutrient required for the normal functioning of many organisms in the ecosystem. However, presence of excess phosphate into the aquatic systems leads to eutrophication which can promote harmful algal growth and decrease the amount of dissolved oxygen in water. Municipal, industrial and agricultural run-off wastewaters are the major point sources for phosphate discharges. There are different methods to remove phosphates from water. Among these, adsorption is the most widely accepted method for phosphate removal because of its high efficiency, minimum cost, easy and simple operation and applicability at lower concentrations. The emphasis of this review, is to consolidate low cost, environmentally friendly humic acid coated magnetite nanoparticles (HA-MNP) and its application for the remediation of phosphate from aqueous media. The magnetic nanoparticles could be easily separated from the reaction mixture by using a simple hand held magnet and adsorption studies demonstrate the fast and effective separation of phosphate with maximum removal efficiency > 90% at pH 6.6. The adsorption behavior follows the Freundlich isotherm and the removal of phosphate is found higher at acidic and neutral pH compared to basic conditions. The nanoparticles exhibit good selectivity and adsorption efficiency for phosphate in the presence of co-existing ions such as Cl-, ?and??with some inhibition effect by??and finally, the effect of temperature on the adsorption reveals that the process is endothermic and spontaneous.展开更多
The core of the natural product chemistry laboratory is isolation secondary metabolit</span><span style="font-family:Verdana;">e</span><span style="font-family:""><s...The core of the natural product chemistry laboratory is isolation secondary metabolit</span><span style="font-family:Verdana;">e</span><span style="font-family:""><span style="font-family:Verdana;">s. One of the potential secondary metabolites for isolation in the natural product chemistry laboratory is routine (quercetin-3-O-glycosides). Routine (Quercetin-3-O-glycoside) has been isolated from ethanol extract of rubber cassava leaves (</span><i><span style="font-family:Verdana;">Manihot glaziovii </span></i><span style="font-family:Verdana;">MA). Isolation was done by maceration and recrystallization. The isolation method used in this study is complemented by the isolation method published. The isolated (Quercetin-3-O-glycoside) routine using this method obtained a yield of 0.118% of the total dried leaf extract. The routine (Quercetin-3-O-glycoside) was identified using a standard routine. Routine can be further utilized in the world of medicine as an amplifier of capillary structure, reducing the permeability and fragility of blood vessels.展开更多
Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant ...Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant activity and compared the antioxidant efficacy of the extracts from the three fresh edible algae with a standard solution, 3-tert-butyl-4-hydroxyanisole （BHA）. This study found that an extract ofNostochopsis spp. was the highest antioxidant activity to DPPH free radical between 32.1 and 87.5, the highest amount of beta-carotene was 4.71-7.09 mg/g and the highest amount of phenol in fresh edible algae extracts from Microspora was between 9.37 and 37.02 mg/g. The highest vitamin C in Microspora was between 110.41-138.53 mg/100 g.展开更多
A wet chemistry synthesis of Pt-Ce doped catalysts on carbon Vulcan support using an impregnation method with EDTA is presented. The composite catalyst was characterized by XRD, XPS and TEM. The catalytic activity of ...A wet chemistry synthesis of Pt-Ce doped catalysts on carbon Vulcan support using an impregnation method with EDTA is presented. The composite catalyst was characterized by XRD, XPS and TEM. The catalytic activity of the prepared material was tested in a direct fuel cell using methanol, ethanol and hydrogen as fuels. The polarization and power curves showed that the Vulcan/Pt/Ce(III) doped catalysts improved the performance of the fuel cells when compared with Vulcan-Pt anode materials.展开更多
Lithium-sulfur(Li-S)battery,as a promising next-generation high-energy-density battery,suffers from lithium polysulfides(LPSs)shuttle and Li dendrites issues.Porous crystalline framework-based membranes as separator c...Lithium-sulfur(Li-S)battery,as a promising next-generation high-energy-density battery,suffers from lithium polysulfides(LPSs)shuttle and Li dendrites issues.Porous crystalline framework-based membranes as separator can effectively absorb and restrain LPSs but without precise structural design principal exploration and mechanism studies.Herein,bio-inspired 1D oriented lithium-ion transport channels with molecular negatively charged PO_(3)(-1)have been developed in hybrid tetrazole frameworks for promoting the transmission of Li+ions.The theoretical calculations and in situ spectroscopy demonstrated the higher binding energy and inhibited diffusion of LPSs in PO_(3).The assembled PP@PO_(3)Janus separator in Li-S coin cell delivered a high initial capacity of 1410.9 mAhg^(-1)at 0.1 C and a low attenuation rate of 0.038%per cycle over 500 cycles at 5 C.Besides,the high capacities of 862,542 and 409 mAhg^(-1)based on high-sulfur-loading cathodes of 2.6,3.8 and 5.0 mg cm^(-2)at 0.5 C were achieved,respectively.Moreover,the punch battery of PO_(3)@PP separator with S-cathode of 1.2 mg cm^(-2)has been developed for demonstrating its potentials commercial application,which displays impressive capacity of 873.4 mAhg-1with the retention of~78.9%over 50 cycles.展开更多
The AML1-ETO fusion transcription factor is generated by the t(8;21)translocation,which is present in approximately 4%-12% of adult and 12%-30% of pediatric acute myeloid leukemia(AML)patients.Both human and mouse mod...The AML1-ETO fusion transcription factor is generated by the t(8;21)translocation,which is present in approximately 4%-12% of adult and 12%-30% of pediatric acute myeloid leukemia(AML)patients.Both human and mouse models of AML have demonstrated that AML1-ETO is insufficient for leukemogenesis in the absence of secondary events.In this review,we discuss the pathogenetic insights that have been gained from identifying the various events that can cooperate with AML1-ETO to induce AML in vivo.We also discuss potential therapeutic strategies for t(8;21)positive AML that involve targeting the fusion protein itself,the proteins that bind to it,or the genes that it regulates.Recently published studies suggest that a targeted therapy for t(8;21)positive AML is feasible and may be coming sometime soon.展开更多
Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization...Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization of ethylene/1-hexene with zirconocene/MMAO catalyst.It was found that the size of the nano-TiO2 crystallite nanoparticles can influence the catalytic activity in the polymerization system.The larger nano-TiO2 crystallites provided better catalytic activity in the polymerization system due to more space for monomer attack.In addition,by thermo-gravimetric analysis,it can be seen that the larger nano-TiO2 crystallites also exhibited lower interaction with available MMAO.Consequently,the MMAO reacted more efficiently with the zirconocene catalyst during the activation process,and enhanced polymerization catalysis.All the polymer nanocomposites products did not have well defined melting temperature indicating non-crystalline polymers.This is due to the high amount of hexene incorporation(based on 13C NMR).The difference in crystallite sizes of the nano-TiO2 also affected how 1-hexene became incorporated into the polymer nanocomposites.The smaller crystallite size of nano-TiO2 allowed greater 1-hexene incorporation due to depression of the reactivity of the ethylene.The contribution of this work helps develop a better understanding of the role of nano-TiO2 in the catalytic activity of the polymerization system and in the microstructure of the polymer composite product.However,this study only considers work on the laboratory scale,so for commercial application of these results,it is necessary to scale up the polymerization process.It is only at this stage,that other physical properties,such as the mechanical properties of these materials can be sensibly determined.展开更多
基金support from the Ministry of Higher Education Malaysia under grant HICOE-2023-005.
文摘A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.
基金the University of Cartagena for funding through the Strengthening Project Acta 048-2023.
文摘The extensive use of polymeric materials in single-use packaging has driven the need to develop biodegradable alternatives.This study investigates the incorporation of graphene oxide(GO)and Moringa oleifera seed oil(MOSO)into a gelatin matrix to create polymer films and evaluate their potential as active packaging materials.The properties of these films were evaluated using structural,thermal,mechanical,optical,and physicochemical methods to determine their suitability for food packaging applications.The results showed that GO and MOSO were homogeneously dispersed in the gelatin matrix,forming colloidal particles(around 5μm in diameter).The addition of GO increased opacity by approximately 20 times the base value while MOSO affected light transmittance without impacting opacity.Mechanical properties were affected differently,GO acted as a crosslinking agent reducing elongation and increasing tensile strength at break,on the other hand MOSO acted as a plasticizer,making films more plastic increasing elongation a 30%.These effects counteracted each other,and similar behavior was recorded in differential scanning calorimetry.The films exhibited an improved water vapor resistance,which is crucial for food packaging.These findings indicate that the incorporation of GO and MOSO into a gelatin matrix may produce biodegradable polymer films with enhanced properties,suitable for active packaging in the food industry.
基金supported by the City University of Hong Kong(9380107 and 7005943)King Abdullah University of Science and Technology,and Agency for Science,Technology and Research(C230415018 and C231218003).
文摘Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec tive products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties.Herein,we construct an efficient,concentrated sunlight-driven CO_(2)RR setup consisting of InGaP/GaAs/Ge triple-junction cell as a photoanode and oxide-derived Au(Ox-Au)as a cathode to perform the unassisted PEC CO_(2)RR.Under one-sun illumination,a maximum operating current density of 11.5 mA cm^(-2) with an impressive Faradaic efficiency(FE)of~98%is achieved for carbon monoxide(CO)production,leading to a solar-to-fuel conversion efficiency of~15%.Under concentrated intensity of 10 sun,the photoanode records a maximum current density of~124 mAcm^(-2) and maintains~60%of FE for CO production.The results demonstrate crucial advancements in usingⅢ-Ⅴbased photoanodes for concentrated PEC CO_(2)RR.
文摘The first successful generation of induced pluripotent stem （iPS） cells from somatic cells was accomplished by introducing four genes into the cell, 0Ct3/4, Sox2, Klf4, and c-myc [1]. While a tour-de-force, this approach to iPS cell generation is inefficient, and unlikely to be directly translated into therapeutic use since it involves the use ofretroviruses to introduce these genes into the cell. Subsequent studies have used non-integrating genetic elements,
基金the financial support provided by UMS Great(GUG0217-1/2018),which played a crucial role in the completion of this study.
文摘Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.
文摘Crude oil pollution in the Niger Delta, perpetrated by both local communities and industrial actors, has brought about soil pollution with its consequent ecological, human health and food challenges. The purpose of this research was to examine the concentration and distribution of heavy metals in soil from communities contaminated by crude oil in Niger Delta, and to evaluate the potential health risks to residents from exposure to these contaminants. To achieve this, soil samples were collected from the Ihwrekreka community and analyzed for heavy metal content using inductively coupled plasma mass spectrometry (ICP-MS). The analytical results in mg/kg revealed a significant metals pollution level derived from the oil spill in the soil ranging from 4.85 - 17,078 (Cu), 1.01 - 16.1 (Cd), 0.22 - 36.8 (Cr), 8.28 - 40.9 (Ni), 7.51 - 6474 (Pb), and 8.84 - 12,851 (Zn) respectively. Most of the metals were above the permissible limits of World Health Organization, with Cu, Zn, and Pb as the most contaminating metals. Lead was found to be the main contributor to the hazard index (HI) values for both children and adults in the study area, with its concentration exceeding the permitted limits set by the WHO and the EC. The hazard index (HI) values of Pb, Cu, Zn, Cd, Ni, and Cr were significantly higher than 1. These findings suggest that the release of heavy metals from an oil-contaminated site may pose a risk to human health and the environment.
基金Supported by the National High Technology Research and Development Program of China (2008AA03Z3472294,2009AA302410)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2010)+1 种基金the Guangdong Province Sci & Tech Bureau (2006B12401006, 2008A080800024)the Chinese Universities Basic Research Founding
文摘The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by BET, XRD (X-ray diffraction), TPR (temperature programmed reduction), IR (infra-red adsorption), NH 3-TPD (temperature programmed desorption) and CO 2-TPD (temperature programmed desorption) techniques. The results showed that the surface area of catalysts decreased with increasing metal content, and the metals as well as Cu-Ni alloy co-existed on the reduced catalyst surface. There existed interaction between metal and carrier, and moreover, metal particles affected obviously the acidity and basicity of carrier. The large amount of basic sites facilitated the activation of methanol to methoxyl species and their subsequent reaction with activated carbon dioxide. The catalysts were evaluated in a continuous tubular fixed-bed micro-gaseous reactor and the catalyst with bimetal loading of 20% (by mass) had best catalytic activities. Under the conditions of 393 K, 1.1 MPa, 5 h and gas space velocity of 510 h 1 , the selectivity and yield of DMC were higher than 86.0 % and 5.0 %, respectively.
文摘A molecular imprinting polymer technique was successfully applied to precipitation polymerization by using styrene as a functional monomer, curcuminoids as templates, acetonitrile as a porogenic solvent,benzoyl peroxide as the initiator, and ethylene glycol dimethacrylate as the crosslinker. The effects of interaction on the adsorption capacity of the molecularly imprinted polymer(MIP) and non-imprinted polymer(NIP) were investigated. A comparison of the adsorption capacity for MIP and NIP indicated that the NIP had the lowest adsorption capacity. The curcuminoid-imprinted polymer(Cur-MIP) was synthesized from 0.0237 mmol of styrene, 47.0 g of acetonitrile, 1.0238 mmol of ethylene glycol dimethacrylate, 0.0325 mmol of curcuminoids, and 0.2480 mmol of benzoyl peroxide. A high-performance liquid chromatography method with fluorescence detection was developed and validated for various chromatographic conditions for the determination of the curcuminoids in turmeric samples. The sample solution was separated using the Cur-MIP via solid-phase extraction and analyzed on a Brownlee analytical C_(18) column(150 mm ×6 mm, 5 mm) using an isocratic elution consisting of acetonitrile and 0.1%trichloroacetic acid(40:60, v/v). The flow rate was maintained at 1.5 m L/min. The fluorescence detector was set to monitor at λex? 426 nm and λem? 539 nm. The quantification limit values were found to be16.66, 66.66, and 33.33 mg/L for curcumin, demethoxycurcumin, and bisdemethoxycurcumin, respectively. Thus, we concluded that the Cur-MIP and high-performance liquid chromatographic-fluorescence method could be applied to selective extraction and could be used as a rapid tool for the determination of curcuminoids in medicinal herbal extracts.
基金the China High-Tech Development 863 Program,Guangdong Province Sci & Tech Bureau(No.2006B12401006)Guangzhou Sci & Tech Bureau(No.2005U13D2031,2007Z2-D2031)financial support of this work National University of Singapore for financial support.
文摘Novel Cu-Ni/C has been prepared and utilized as an efficient catalyst system in direct synthesis of DMC from CH3OH and CO2.
基金Department of Textile Engineering, Chemistry and Science at North Carolina State University for the financial support
文摘Herein, we report the design and synthesis of three new D-A type metal-free carbazole based dyes（S1-3）as effective co-sensitizers for dye-sensitized solar cell（DSSC） sensitized with Ru（Ⅱ） complex（NCSU-10）.In this new design, the electron rich carbazole unit was attached to three different electron withdrawing/anchoring species, viz. 4-amino benzoic acid, sulfanilic acid and barbituric acid. The dyes were characterized by spectral, photophysical and electrochemical analysis. Their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of the structures of these co-sensitizers on the photovoltaic performances. Further, S1-3 dyes were co-sensitized along with a well-known NCSU-10 dye in order to broaden the spectral response of the co-sensitized devices and hence improve the efficiency. The photovoltaic performance studies indicated that, the device fabricated using S1 dye as co-sensitizer with 0.2 mM of NCSU-10 exhibited improved PCE of 9.55% with JSC of 22.85 mA cm-2, VOC of 0.672 V and FF of 62.2%, whereas the DSSC fabricated with dye NCSU-10（0.2 mM） alone displayed PCE of 8.25% with JSC of 20.41 mA cm-2, VOC of 0.667 V and FF of 60.6%. Furthermore, electronic excitations simulated using time-dependent DFT, were in good agreement with the experimentally obtained results of the co-sensitizers, indicating that the exchange-correlation function and basis set utilized for predicting the spectra of the co-sensitizers are quite appropriate for the calculations. In conclusion, the results showed the potential of simple organic co-sensitizers in the development of efficient DSSCs.
基金supported by the National Basic Research Program of China(Grant No.2003CB214600)China Postdoctoral Science Foundation(Grant No.20080431246)the Program for Changjiang scholars and Innovative Research Team in University(Grant No.IRT0559).
文摘Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies, sedimentary provenance analysis and thickness distribution of the Mesozoic Ordos Basin, it is demonstrated that the depocenters migrated counterclockwise from southeast to the north and then to the southwest from the Middle-Late Triassic to the Early Cretaceous. There were no unified and larger-scale accumulation centers except several small isolated accumulation centers before the Early Cretaceous. The reasons why belts of relatively thick strata were well developed in the western basin in several stages are that this area is near the west boundary of the original Ordos Basin, there was abundant sediment supply and the hydrodynamic effect was strong. Therefore, they stand for local accumulation centers. Until the Early Cretaceous, depocenters, accumulation centers and subsidence centers were superposed as an entity in the southwest part of the Ordos Basin. Up to the end of the Middle Jurassic, there still appeared a paleogeographic and paleostructural higher-in-west and lower-in-east framework in the residual basin to the west of the Yellow River. The depocenters of the Ordos Basin from the Middle-Late Triassic to the Middle Jurassic were superposed consistently. The relatively high thermal maturation of Mesozoic and Paleozoic strata in the depocenters and their neighborhood suggest active deep effects in these areas. Generally, superposition of depocenters in several periods and their consistency with high thermal evolution areas reveal the control of subsidence processes. Therefore, depocenters may represent the positions of the subsidence centers. The subsidence centers （or depocenters） are located in the south of the large-scale cratonic Ordos Basin. This is associated with flexural subsidence of the foreland, resulting from the strong convergence and orogenic activity contemporaneous with the Qinling orogeny.
基金the China High-Tech Development 863 Program(N0.2009AA03Z2340)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2010)+2 种基金Guangdong Province Sci & Tech Bureau(Key Strategic Project Nos. 2008A080800024 and 10151027501000096)Chinese Universities Basic Research Founding for financial support of the work.National University of Singapore for financial support
文摘The Mo-promoted Cu-Fe bimetal catalysts were prepared and used for the formation of dimethyl carbonate （DMC） from CO2 and methanol. The catalysts were characterized by X-ray diffraction （XRD）, temperature programmed reduction （TPR）, laser Raman spectra （LRS）, energy dispersive spectroscopy （EDS） and temperature programmed desorption （TPD） techniques. The experimental results demonstrated that the Mo promoters can decrease the reducibility and increase the dispersion of Cu-Fe clusters, The concentration balance of base-acid sites can be readily adjusted by changing the Mo content. The moderate concentration balance of acid and base sites was in favor of the DMC formation, Under optimal experimental conditions, the highest methanol conversion of 6,99% with a DMC selectivity of 87.7% can be obtained when 2.5 wt% of Mo was loaded.
文摘Cyanine dyes of zero/bis-zero methine incorporating imid-azo(1,2-a)Pyridine (quinoline) or pyrazino(1,2-a)pyridine (quinoline) with stable C-N bond were synthesized using keto-oxime methylene C-link heterocyclic quaternary salts [1-phenyl-3-methyl-pyrazolino-4-keto-oxime-α-methylene-bis-pyridin-(quinoin)-1(4)-di-ium-iodide(ethiodide) salts and 1-phenyl-3-methyl-pyrazolino- 4-ketooxime-α-methylene-N-2-methyl-bis pyridin (quinoin)-1(4)-di-ium-iodide(ethiodide) salts]. Such heterocyclic precursors and related dyes were identified by elemental and spectral analyses. The absorption spectra properties of such dyes were investigated in 95% Ethanol to attempt and throw some light on the influence of such new heterocyclic nuclei and to compare or evaluate spectral behaviors. The absorption spectra of dyes in different pure solvents were examined in the visible region showing solvatochromism and the colour changes of dyes with solvents having different polarities. This permits a selection of the optimal solvent (fractional solvent) when such dyes are applied as photosensitizers. The spectral behavior of some selected newly synthesized cyanine dyes is observed in mixed solvents of different polarities and progressively increasing quantities of one solvent over the other were studied and showed an increase in the absorbance of CT band with increasing proportion of that solvent. Evidence for hydrogen bond formation between the solute molecules and solvent molecules allows measurement of certain energies such as hydrogen bonding, orientation, and free energies.
文摘Phosphate is a primary nutrient required for the normal functioning of many organisms in the ecosystem. However, presence of excess phosphate into the aquatic systems leads to eutrophication which can promote harmful algal growth and decrease the amount of dissolved oxygen in water. Municipal, industrial and agricultural run-off wastewaters are the major point sources for phosphate discharges. There are different methods to remove phosphates from water. Among these, adsorption is the most widely accepted method for phosphate removal because of its high efficiency, minimum cost, easy and simple operation and applicability at lower concentrations. The emphasis of this review, is to consolidate low cost, environmentally friendly humic acid coated magnetite nanoparticles (HA-MNP) and its application for the remediation of phosphate from aqueous media. The magnetic nanoparticles could be easily separated from the reaction mixture by using a simple hand held magnet and adsorption studies demonstrate the fast and effective separation of phosphate with maximum removal efficiency > 90% at pH 6.6. The adsorption behavior follows the Freundlich isotherm and the removal of phosphate is found higher at acidic and neutral pH compared to basic conditions. The nanoparticles exhibit good selectivity and adsorption efficiency for phosphate in the presence of co-existing ions such as Cl-, ?and??with some inhibition effect by??and finally, the effect of temperature on the adsorption reveals that the process is endothermic and spontaneous.
文摘The core of the natural product chemistry laboratory is isolation secondary metabolit</span><span style="font-family:Verdana;">e</span><span style="font-family:""><span style="font-family:Verdana;">s. One of the potential secondary metabolites for isolation in the natural product chemistry laboratory is routine (quercetin-3-O-glycosides). Routine (Quercetin-3-O-glycoside) has been isolated from ethanol extract of rubber cassava leaves (</span><i><span style="font-family:Verdana;">Manihot glaziovii </span></i><span style="font-family:Verdana;">MA). Isolation was done by maceration and recrystallization. The isolation method used in this study is complemented by the isolation method published. The isolated (Quercetin-3-O-glycoside) routine using this method obtained a yield of 0.118% of the total dried leaf extract. The routine (Quercetin-3-O-glycoside) was identified using a standard routine. Routine can be further utilized in the world of medicine as an amplifier of capillary structure, reducing the permeability and fragility of blood vessels.
文摘Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant activity and compared the antioxidant efficacy of the extracts from the three fresh edible algae with a standard solution, 3-tert-butyl-4-hydroxyanisole （BHA）. This study found that an extract ofNostochopsis spp. was the highest antioxidant activity to DPPH free radical between 32.1 and 87.5, the highest amount of beta-carotene was 4.71-7.09 mg/g and the highest amount of phenol in fresh edible algae extracts from Microspora was between 9.37 and 37.02 mg/g. The highest vitamin C in Microspora was between 110.41-138.53 mg/100 g.
基金NASA-URC Center of Advanced Nanoscale Materials(NNX10AQ17A)NSF-NSEC Center for Hierarchical Manufacturing(CHM-CMMI-053117)for the financial support of this research
文摘A wet chemistry synthesis of Pt-Ce doped catalysts on carbon Vulcan support using an impregnation method with EDTA is presented. The composite catalyst was characterized by XRD, XPS and TEM. The catalytic activity of the prepared material was tested in a direct fuel cell using methanol, ethanol and hydrogen as fuels. The polarization and power curves showed that the Vulcan/Pt/Ce(III) doped catalysts improved the performance of the fuel cells when compared with Vulcan-Pt anode materials.
基金supported by the National Natural Science Foundation of China(22271178)the International Cooperation Key Project of Science and Technology Department of Shaanxi,China(2022KWZ-06)+4 种基金the Youth Talent Promotion Project of Science and Technology Association of Universities of Shaanxi Province(20210602)the Research Project of Xi’an Science and Technology Bureau(2022GXFW0011)the Science and Technology New Star in Shaanxi Province(2023KJXX-045)the Shaanxi Provincial Department of Education Service Local Special Projectthe Industrialization Cultivation Project(23JC007)。
文摘Lithium-sulfur(Li-S)battery,as a promising next-generation high-energy-density battery,suffers from lithium polysulfides(LPSs)shuttle and Li dendrites issues.Porous crystalline framework-based membranes as separator can effectively absorb and restrain LPSs but without precise structural design principal exploration and mechanism studies.Herein,bio-inspired 1D oriented lithium-ion transport channels with molecular negatively charged PO_(3)(-1)have been developed in hybrid tetrazole frameworks for promoting the transmission of Li+ions.The theoretical calculations and in situ spectroscopy demonstrated the higher binding energy and inhibited diffusion of LPSs in PO_(3).The assembled PP@PO_(3)Janus separator in Li-S coin cell delivered a high initial capacity of 1410.9 mAhg^(-1)at 0.1 C and a low attenuation rate of 0.038%per cycle over 500 cycles at 5 C.Besides,the high capacities of 862,542 and 409 mAhg^(-1)based on high-sulfur-loading cathodes of 2.6,3.8 and 5.0 mg cm^(-2)at 0.5 C were achieved,respectively.Moreover,the punch battery of PO_(3)@PP separator with S-cathode of 1.2 mg cm^(-2)has been developed for demonstrating its potentials commercial application,which displays impressive capacity of 873.4 mAhg-1with the retention of~78.9%over 50 cycles.
基金supported by a Leukemia Lymphoma Society SCOR grant(S.D.N.)a Leukemia Lymphoma Society fellowship(L.W.)+1 种基金an Empire State Stem Cell Scholar award(L.W.)a New York State Stem Cell Science grant(S.D.N.).
文摘The AML1-ETO fusion transcription factor is generated by the t(8;21)translocation,which is present in approximately 4%-12% of adult and 12%-30% of pediatric acute myeloid leukemia(AML)patients.Both human and mouse models of AML have demonstrated that AML1-ETO is insufficient for leukemogenesis in the absence of secondary events.In this review,we discuss the pathogenetic insights that have been gained from identifying the various events that can cooperate with AML1-ETO to induce AML in vivo.We also discuss potential therapeutic strategies for t(8;21)positive AML that involve targeting the fusion protein itself,the proteins that bind to it,or the genes that it regulates.Recently published studies suggest that a targeted therapy for t(8;21)positive AML is feasible and may be coming sometime soon.
基金the Thailand Research Fund (TRF) for its support of the DBG52-B Jongsomjit Project
文摘Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization of ethylene/1-hexene with zirconocene/MMAO catalyst.It was found that the size of the nano-TiO2 crystallite nanoparticles can influence the catalytic activity in the polymerization system.The larger nano-TiO2 crystallites provided better catalytic activity in the polymerization system due to more space for monomer attack.In addition,by thermo-gravimetric analysis,it can be seen that the larger nano-TiO2 crystallites also exhibited lower interaction with available MMAO.Consequently,the MMAO reacted more efficiently with the zirconocene catalyst during the activation process,and enhanced polymerization catalysis.All the polymer nanocomposites products did not have well defined melting temperature indicating non-crystalline polymers.This is due to the high amount of hexene incorporation(based on 13C NMR).The difference in crystallite sizes of the nano-TiO2 also affected how 1-hexene became incorporated into the polymer nanocomposites.The smaller crystallite size of nano-TiO2 allowed greater 1-hexene incorporation due to depression of the reactivity of the ethylene.The contribution of this work helps develop a better understanding of the role of nano-TiO2 in the catalytic activity of the polymerization system and in the microstructure of the polymer composite product.However,this study only considers work on the laboratory scale,so for commercial application of these results,it is necessary to scale up the polymerization process.It is only at this stage,that other physical properties,such as the mechanical properties of these materials can be sensibly determined.
