Drug delivery by nanocarriers requires characterizations of suitable particle size, high drug loading and safety. In this work, we prepared an amphiphilic dendrimer modified PEG-PLA mixed nanoparticles（NPs） by a dou...Drug delivery by nanocarriers requires characterizations of suitable particle size, high drug loading and safety. In this work, we prepared an amphiphilic dendrimer modified PEG-PLA mixed nanoparticles（NPs） by a double emulsion-solvent evaporation（DESE） method. The particle size and drug encapsulation efficacy（EE） were compared to evaluate and optimize the preparation parameters. The mixed NPs had average size ranging from（102±1） nm to（137±5） nm, and the zeta potential turned to positive with incorporation of the amphiphilic dendrimer. The NPs showed different EE of docetaxel（DTX） and paclitaxel（PTX） with higher affinity to more lipophilic PTX. The blank mixed NPs showed little cytotoxicity, and the DTX-loaded NPs could effectively facilitate the antiproliferation activity on PC-3 cells. The NPs could be used as an effective drug delivery system, and its anti-tumor effect is worthy of further study.展开更多
Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapo...Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapor in the air. It was found that the particles range from 70 to 100nm in average particle size. The effect of experimental parameters was investigated, the increase of the air flow-rates reduced the average particle size, while increasing the evaporation temperature and the amount of metal charged increased the average particle size. TEM of the particles collected showed that the crystal habits of particles have a tetrapod-like of wurtzite structure consists of four needle crystals. It was found by electron diffraction that all particles were single crystal.展开更多
Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determine...Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determined as: ZnO 0.25g, pH 7, p-NCBconcentration 30mg/L. These variables in terms of the degradation rate have beendiscussed, which was defined as the rate of the initial degradation to the final degrada-tion of p-NCB. When all of the experimental degradation rate values are plotted as afunction of irradiation time, all of the points appeared on a single line for wide range ofp-NCB degradations. On the basis of these results, it has been concluded that at lowerZnO catalyst amount, much of the light is transmitted through the slurry in the con-tainer beaker, while at higher catalyst amount, all the incident photons are observedby the slurry. Degradation rates of p-NCB were found to decrease with increasingsolution pH. It has been concluded that the maximum degradation rate values of p-NCB under principally the same experimental conditions mentioned above are 97.4%,98.8% and 95.5% at 100min respectively. The results suggest that the photocatalyticdegradation is initiated by an oxidation of the p-NCB through ZnO surface-adsorbedhydroxyl radicals. Absorption spectra are recorded using spectrophotometer before andafter UV-irradiation in the wavelength range 200-400nm at room temperature. Itis found that the variation of irradiation time over the range 20-100min resulted inchange in the form of the spectrum linear absorption and a higher maximum valuewill be obtained at longer irradiation time.展开更多
SiC/SiO2 nanochains were synthesized on a carbon fiber substrate by a catalyst-free thermal evaporation method in the Ar/CO atmosphere.X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),scanning ele...SiC/SiO2 nanochains were synthesized on a carbon fiber substrate by a catalyst-free thermal evaporation method in the Ar/CO atmosphere.X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)revealed that the as-synthesized SiC/SiO2 nanochains are composed of single-crystalline SiC nanowires and amorphous SiO2 beads.The introduction of CO can promote the formation of SiO2,so that the SiC/SiO2 nanochains are subsequently formed during cooling.In addition,the photoluminescence spectrum of SiC/SiO2 nanochains showed a broad emission peak at around 350 nm,which is ascribed to the oxygen discrepancy in the SiO2 beads as well as the SiC/SiO2 interfacial effect.These findings can provide guidance for further study of the vapor growth of 1D SiC-based materials.展开更多
Nanometer Zn particles with mean diameters 12-100nm made by evaporating its powders in argon gas were studied mainly by X-ray diffraction and electron microscopy. They are collected at various distances and those fact...Nanometer Zn particles with mean diameters 12-100nm made by evaporating its powders in argon gas were studied mainly by X-ray diffraction and electron microscopy. They are collected at various distances and those factors influencing the mean particle size were studied. The optimal synthetic conditions were obtained, i.e., evaporation temperature is 1200℃; argon flow rate is 0.4m3/h; amount of powder charged is 3g; distance from evaporation source is 10cm. It was found that the size of particles was governed by argon flow rate, evaporation temperature, amount of metal charged and distance from the source. The size increases remarkably with distance in the space where no metal vapor exists. This implies that the crystallites grow by coalescence. Electron micrographs and diffraction patterns are reproduced to show the size, shape and state of oxidations. Nanoparticles with definite crystal habits were sometimes observed among those with irregular ones.展开更多
Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds（VOCs）. Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparati...Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds（VOCs）. Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method（CRM） using proton transfer reaction mass spectrometer（PTR-MS）.Compositions of 56 PAMS（photochemical assessment monitoring station） nonmethane hydrocarbons（NMHCs） were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57 ？ 4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. We suggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control.展开更多
In the present study,an extended-release(ER)suspension of guanfacine hydrochloride(GFN)was successfully formulated using a self-synthesized cation-exchange resin characterized by a narrow particle size distribution.Th...In the present study,an extended-release(ER)suspension of guanfacine hydrochloride(GFN)was successfully formulated using a self-synthesized cation-exchange resin characterized by a narrow particle size distribution.The drug-resin complex was prepared through a static adsorption method,employing the resin as a pharmaceutical carrier.Subsequently,guanfacine hydrochloride-coated microcapsules(GFN-CM)were fabricated via an emulsion solvent evaporation technique to achieve sustained-release functionality.Characterization revealed that the in-house resin exhibited a smoother surface and a narrower size distribution(Span value:0.74)compared to the commercial counterpart,Amberlite®IRP69.In vitro release studies demonstrated that the GFN-CM followed a zero-order kinetic model over 10 h,with a cumulative drug release of 81.88%observed at 12 h.Furthermore,pharmacokinetic evaluation in New Zealand rabbits showed that the mean residence time(MRT0–24)of the GFN suspension extended from 7.619 to 8.336 h,displaying a more stable plasma concentration-time profile and an average relative bioavailability(Fr)of 111.36% compared to marketed ER GFN tablets.These findings highlighted the successful development of a novel cation exchange resin-based delivery system,offering a promising strategy for enhancing the performance of ER pharmaceutical formulations.展开更多
A new charge transfer cocrystal of 1,2,4,5-tetracyanobenzene(TCNB)-phenazine(PTC)was prepared by solvent evaporation method.The donor and acceptor molecules of cocrystal are stacked face to face with a mixed-stacking,...A new charge transfer cocrystal of 1,2,4,5-tetracyanobenzene(TCNB)-phenazine(PTC)was prepared by solvent evaporation method.The donor and acceptor molecules of cocrystal are stacked face to face with a mixed-stacking,implying a strong charge transfer(CT)interactions in the cocrystal system.The spectroscopic studies,single-crystal X-ray diffraction structure,density functional theory(DFT)and Hirschfield surfaces calculations are carried out to explore the relationship between structure and properties of cocrystal system,which show that the intermolecular interactions in PTC are stronger than those of single components,leading to the stability and photophysical behaviors of cocrystal different from their constitute units.This study will be helpful for the design and preparation of multifunctional cocrystal materials.展开更多
Nano-ZnO particle was produced by evaporating zinc powders in air at air flow-rate from 0.2 to 0.6m3/h. Nano-ZnO particles was formed by the oxidation of the evaporated zinc vapor. X-ray diffraction shows the powders ...Nano-ZnO particle was produced by evaporating zinc powders in air at air flow-rate from 0.2 to 0.6m3/h. Nano-ZnO particles was formed by the oxidation of the evaporated zinc vapor. X-ray diffraction shows the powders to be ZnO with lattice parameters of a=0.3249nm and c=0.5205nm. The particle size is dependent upon the transit time from the source to the collection area. The size of particles was ranged between 81 to 103nm. The average density resulted was 4.865g/cm3. Normal ZnO and nano-ZnO were investigated to use them in aluminum metallurgy as an inert anode material. A certain amount of both oxides were molded subsequently inserted to the molten cryolite-aluminum oxide to investigate the corrosive behavior of both oxides. When the sintering temperature increased up to 1300℃, the weight loss ratio rose to 5.01%-7.33% and up to 7.67%-10.18% for nano-ZnO and normal ZnO, respectively. However, when the samples in the molten cryolite aluminum oxide were put for long time, the corrosive rate was found to be higher. It was found that the corrosive loss weight ratio of nano-ZnO anode was much lower than the normal one made from ordinary-ZnO providing that the nano-ZnO is more possible to be use inert anode material.展开更多
The poor dissolution characteristics of water-insoluble drugs are a major challenge for pharmaceutical scientists.Reduction of the particle size/increase in the surface area of the drug is a widely used and relatively...The poor dissolution characteristics of water-insoluble drugs are a major challenge for pharmaceutical scientists.Reduction of the particle size/increase in the surface area of the drug is a widely used and relatively simple method for increasing dissolution rates.The objective of this study was to improve solubility,release and comparability of dissolution of a poorly soluble drug using two different types of formulations(solid dispersions and microspheres).Hydrochlorothiazide was used as a model drug.The solid dispersions and microspheres were prepared by solvent evaporation method using ethyl cellulose,hydroxypropyl methylcellulose in different drug-to-carrier ratios(1:1,1:2 w:w).The prepared formulations were evaluated for interaction study by Fourier transform infrared spectroscopy,differential scanning calorimetry,percentage of practical yield,drug loading,surface morphology by scanning electron microscopy,optical microscopy and in-vitro release studies.The results showed no interaction between the drug and polymer,amorphous state of solid dispersions and microspheres,percentage yield of 42.53%to 78.10%,drug content of 99.60%to 99.64%,good spherical appearance in formulation VI and significant increase in the dissolution rate.展开更多
This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors ...This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors are presented and discussed. It wasfound that residual gas pressure should be low enough to guarantee the unobstructedtransporfation of vapor steam and electron beam; the evaporation method and evapo-ration speed are up to the different vapor pressure deficit of compositions of raw mate-rials; and the substrate temperature could have great influence on the microstructureof the micro--layer laminates.展开更多
[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behn...[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.展开更多
The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI...The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.展开更多
A novel and efficient methodology for obtaining highly active photocatalyst of bi phase TiO 2 with small particle size and high specific surface area was developed by solvent evaporation induced crystallization (SE...A novel and efficient methodology for obtaining highly active photocatalyst of bi phase TiO 2 with small particle size and high specific surface area was developed by solvent evaporation induced crystallization (SEIC) method at low temperature. The prepared TiO 2 powder was characterized with X ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results showed that the photocatalytic activity of the TiO 2 powder prepared by this method approached that of Degussa P25. This may be attributed to the fact that the prepared TiO 2 powder had larger specific surface areas (265 m 2·g -1 ) and smaller crystallite size (about 5 nm), but relatively low crystallinity, as compared with Degussa P25.展开更多
Evapotranspiration(ET)plays a crucial role in the global water and energy cycle.Upscaling instantaneous ET(ET_(i))to daily ET(ET_(d))is vital for thermal-based ET estimation.Conventional methods-such as the constant e...Evapotranspiration(ET)plays a crucial role in the global water and energy cycle.Upscaling instantaneous ET(ET_(i))to daily ET(ET_(d))is vital for thermal-based ET estimation.Conventional methods-such as the constant evaporative fraction method(ConEF),radiation-based method,and evaporative ratio method-often overlook environmental factors,leading to biased estimates of ET_(d)from ET_(i).To resolve this issue,this study aimed to assess four machine learning(ML)algorithms-XGBoost,LightGBM,AdaBoost,and Random Forest-to integrate meteorological and remote sensing data for upscaling ETi across 88 global flux sites.Each ML model was tested with eight different variable combinations.Results indicated that XGBoost exhibited the best performance,with a root mean square error(RMSE)generally below 13 W m^(-2)in estimating ET_(d)from ET_(i).The best variable combination simultaneously considers evaporative fraction,available energy,meteorology factors,remote sensing albedo,normalized vegetation index,and leaf area index.Using this combination,the XGBoost model achieved an R^(2)=0.88 and an RMSE=12.33 W m^(-2),outperforming the ConEF method(R^(2)=0.71 and RMSE=18.86 Wm^(-2))and its expansions.These findings support the application of ML models in ET upscaling,enabling ET estimation across large spatiotemporal scales.展开更多
Among all the phase morphologies of poly(9,9-di-n-octylfluorenyl-2,7-diyl)(PFO),the𝛽phase exhibits a zigzag coplanar arrangement with the highest conjugation degree.As a result,the𝛽-phasePFO has extrao...Among all the phase morphologies of poly(9,9-di-n-octylfluorenyl-2,7-diyl)(PFO),the𝛽phase exhibits a zigzag coplanar arrangement with the highest conjugation degree.As a result,the𝛽-phasePFO has extraordinary prop-erties,including enhanced charge carrier mobility.In this work,we report the formation of high-𝛽-phase PFO in nanoparticles(NPs)due to the synergistic effect of the slow crystallization of PFO in nanodroplet confinement and polystyrene(PS)blending.The𝛽-phase content of PFO can be flexibly tuned by varying the NP size,molec-ular weight(M w),or relative PS content in the NPs.The novel systems demonstrated in this study are likely to provide valuable insights into the𝛽-phase formation mechanism of PFO.As a proof of concept,we further demonstrate that NPs of PFO:PS(1:8)with a higher𝛽-phase content lead to improved photocatalyst efficiency at lower material costs,allowing for novel designs of efficient and visible-light-driven photocatalytic NPs.展开更多
基金National Natural Science Foundation of China(Grant No.81473156,81673365,81273454)Doctoral Foundation of the Ministry of Education(Grant No.20130001110055)National Key Basic Research Program(Grant No.2013CB932501)
文摘Drug delivery by nanocarriers requires characterizations of suitable particle size, high drug loading and safety. In this work, we prepared an amphiphilic dendrimer modified PEG-PLA mixed nanoparticles（NPs） by a double emulsion-solvent evaporation（DESE） method. The particle size and drug encapsulation efficacy（EE） were compared to evaluate and optimize the preparation parameters. The mixed NPs had average size ranging from（102±1） nm to（137±5） nm, and the zeta potential turned to positive with incorporation of the amphiphilic dendrimer. The NPs showed different EE of docetaxel（DTX） and paclitaxel（PTX） with higher affinity to more lipophilic PTX. The blank mixed NPs showed little cytotoxicity, and the DTX-loaded NPs could effectively facilitate the antiproliferation activity on PC-3 cells. The NPs could be used as an effective drug delivery system, and its anti-tumor effect is worthy of further study.
文摘Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapor in the air. It was found that the particles range from 70 to 100nm in average particle size. The effect of experimental parameters was investigated, the increase of the air flow-rates reduced the average particle size, while increasing the evaporation temperature and the amount of metal charged increased the average particle size. TEM of the particles collected showed that the crystal habits of particles have a tetrapod-like of wurtzite structure consists of four needle crystals. It was found by electron diffraction that all particles were single crystal.
文摘Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determined as: ZnO 0.25g, pH 7, p-NCBconcentration 30mg/L. These variables in terms of the degradation rate have beendiscussed, which was defined as the rate of the initial degradation to the final degrada-tion of p-NCB. When all of the experimental degradation rate values are plotted as afunction of irradiation time, all of the points appeared on a single line for wide range ofp-NCB degradations. On the basis of these results, it has been concluded that at lowerZnO catalyst amount, much of the light is transmitted through the slurry in the con-tainer beaker, while at higher catalyst amount, all the incident photons are observedby the slurry. Degradation rates of p-NCB were found to decrease with increasingsolution pH. It has been concluded that the maximum degradation rate values of p-NCB under principally the same experimental conditions mentioned above are 97.4%,98.8% and 95.5% at 100min respectively. The results suggest that the photocatalyticdegradation is initiated by an oxidation of the p-NCB through ZnO surface-adsorbedhydroxyl radicals. Absorption spectra are recorded using spectrophotometer before andafter UV-irradiation in the wavelength range 200-400nm at room temperature. Itis found that the variation of irradiation time over the range 20-100min resulted inchange in the form of the spectrum linear absorption and a higher maximum valuewill be obtained at longer irradiation time.
基金Project(U19A2088)supported by the National Natural Science Foundation of ChinaProject(2019RS2058)supported by the Special Fund for Innovative Construction of Hunan Province,China。
文摘SiC/SiO2 nanochains were synthesized on a carbon fiber substrate by a catalyst-free thermal evaporation method in the Ar/CO atmosphere.X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)revealed that the as-synthesized SiC/SiO2 nanochains are composed of single-crystalline SiC nanowires and amorphous SiO2 beads.The introduction of CO can promote the formation of SiO2,so that the SiC/SiO2 nanochains are subsequently formed during cooling.In addition,the photoluminescence spectrum of SiC/SiO2 nanochains showed a broad emission peak at around 350 nm,which is ascribed to the oxygen discrepancy in the SiO2 beads as well as the SiC/SiO2 interfacial effect.These findings can provide guidance for further study of the vapor growth of 1D SiC-based materials.
文摘Nanometer Zn particles with mean diameters 12-100nm made by evaporating its powders in argon gas were studied mainly by X-ray diffraction and electron microscopy. They are collected at various distances and those factors influencing the mean particle size were studied. The optimal synthetic conditions were obtained, i.e., evaporation temperature is 1200℃; argon flow rate is 0.4m3/h; amount of powder charged is 3g; distance from evaporation source is 10cm. It was found that the size of particles was governed by argon flow rate, evaporation temperature, amount of metal charged and distance from the source. The size increases remarkably with distance in the space where no metal vapor exists. This implies that the crystallites grow by coalescence. Electron micrographs and diffraction patterns are reproduced to show the size, shape and state of oxidations. Nanoparticles with definite crystal habits were sometimes observed among those with irregular ones.
基金funded by the National Natural Science Foundation (Nos. 41125018, 41330635)
文摘Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds（VOCs）. Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method（CRM） using proton transfer reaction mass spectrometer（PTR-MS）.Compositions of 56 PAMS（photochemical assessment monitoring station） nonmethane hydrocarbons（NMHCs） were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57 ？ 4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. We suggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control.
基金The Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX24-2440)the 2021 Zhenjiang sixth“169 project”scientific research projectthe 2023 Qinglan Project of Jiangsu Province,China。
文摘In the present study,an extended-release(ER)suspension of guanfacine hydrochloride(GFN)was successfully formulated using a self-synthesized cation-exchange resin characterized by a narrow particle size distribution.The drug-resin complex was prepared through a static adsorption method,employing the resin as a pharmaceutical carrier.Subsequently,guanfacine hydrochloride-coated microcapsules(GFN-CM)were fabricated via an emulsion solvent evaporation technique to achieve sustained-release functionality.Characterization revealed that the in-house resin exhibited a smoother surface and a narrower size distribution(Span value:0.74)compared to the commercial counterpart,Amberlite®IRP69.In vitro release studies demonstrated that the GFN-CM followed a zero-order kinetic model over 10 h,with a cumulative drug release of 81.88%observed at 12 h.Furthermore,pharmacokinetic evaluation in New Zealand rabbits showed that the mean residence time(MRT0–24)of the GFN suspension extended from 7.619 to 8.336 h,displaying a more stable plasma concentration-time profile and an average relative bioavailability(Fr)of 111.36% compared to marketed ER GFN tablets.These findings highlighted the successful development of a novel cation exchange resin-based delivery system,offering a promising strategy for enhancing the performance of ER pharmaceutical formulations.
基金financial support from the National Key R&D Program(No.2017YFA0204503)the National Natural Science Foundation of China(Nos.51733004,21875158,91833306,51633006)。
文摘A new charge transfer cocrystal of 1,2,4,5-tetracyanobenzene(TCNB)-phenazine(PTC)was prepared by solvent evaporation method.The donor and acceptor molecules of cocrystal are stacked face to face with a mixed-stacking,implying a strong charge transfer(CT)interactions in the cocrystal system.The spectroscopic studies,single-crystal X-ray diffraction structure,density functional theory(DFT)and Hirschfield surfaces calculations are carried out to explore the relationship between structure and properties of cocrystal system,which show that the intermolecular interactions in PTC are stronger than those of single components,leading to the stability and photophysical behaviors of cocrystal different from their constitute units.This study will be helpful for the design and preparation of multifunctional cocrystal materials.
文摘Nano-ZnO particle was produced by evaporating zinc powders in air at air flow-rate from 0.2 to 0.6m3/h. Nano-ZnO particles was formed by the oxidation of the evaporated zinc vapor. X-ray diffraction shows the powders to be ZnO with lattice parameters of a=0.3249nm and c=0.5205nm. The particle size is dependent upon the transit time from the source to the collection area. The size of particles was ranged between 81 to 103nm. The average density resulted was 4.865g/cm3. Normal ZnO and nano-ZnO were investigated to use them in aluminum metallurgy as an inert anode material. A certain amount of both oxides were molded subsequently inserted to the molten cryolite-aluminum oxide to investigate the corrosive behavior of both oxides. When the sintering temperature increased up to 1300℃, the weight loss ratio rose to 5.01%-7.33% and up to 7.67%-10.18% for nano-ZnO and normal ZnO, respectively. However, when the samples in the molten cryolite aluminum oxide were put for long time, the corrosive rate was found to be higher. It was found that the corrosive loss weight ratio of nano-ZnO anode was much lower than the normal one made from ordinary-ZnO providing that the nano-ZnO is more possible to be use inert anode material.
文摘The poor dissolution characteristics of water-insoluble drugs are a major challenge for pharmaceutical scientists.Reduction of the particle size/increase in the surface area of the drug is a widely used and relatively simple method for increasing dissolution rates.The objective of this study was to improve solubility,release and comparability of dissolution of a poorly soluble drug using two different types of formulations(solid dispersions and microspheres).Hydrochlorothiazide was used as a model drug.The solid dispersions and microspheres were prepared by solvent evaporation method using ethyl cellulose,hydroxypropyl methylcellulose in different drug-to-carrier ratios(1:1,1:2 w:w).The prepared formulations were evaluated for interaction study by Fourier transform infrared spectroscopy,differential scanning calorimetry,percentage of practical yield,drug loading,surface morphology by scanning electron microscopy,optical microscopy and in-vitro release studies.The results showed no interaction between the drug and polymer,amorphous state of solid dispersions and microspheres,percentage yield of 42.53%to 78.10%,drug content of 99.60%to 99.64%,good spherical appearance in formulation VI and significant increase in the dissolution rate.
基金This work was supported by the Natural Science Foundation of Heilongjiang Province(No.E01-07)Postdoctoral Science Foundation of China(No.LB0047).
文摘This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors are presented and discussed. It wasfound that residual gas pressure should be low enough to guarantee the unobstructedtransporfation of vapor steam and electron beam; the evaporation method and evapo-ration speed are up to the different vapor pressure deficit of compositions of raw mate-rials; and the substrate temperature could have great influence on the microstructureof the micro--layer laminates.
文摘[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.
基金Supported by the National Natural Science Foundation of China （20906052）, the Science Foundation of Nantong City Municipality （K2007011, K2008023）, the Science Foundation of Nantong University （08R08） and the University Science Research Project of Jiangsu Province （09KJB530008）.
文摘The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.
基金theNationalNaturalScienceFoundationofChina (No .5 0 2 72 0 49)
文摘A novel and efficient methodology for obtaining highly active photocatalyst of bi phase TiO 2 with small particle size and high specific surface area was developed by solvent evaporation induced crystallization (SEIC) method at low temperature. The prepared TiO 2 powder was characterized with X ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results showed that the photocatalytic activity of the TiO 2 powder prepared by this method approached that of Degussa P25. This may be attributed to the fact that the prepared TiO 2 powder had larger specific surface areas (265 m 2·g -1 ) and smaller crystallite size (about 5 nm), but relatively low crystallinity, as compared with Degussa P25.
基金supported by the Excellent Young Scholars Fund of Hebei Natural Science Foundation[No.D2023205012]Doctoral(Post-Doctoral)Research Startup Fund of Hebei Normal University[No.L2023B30]+1 种基金the National Natural Science Foundation of China[No.42101382,No.42201407]the Shandong Provincial Natural Science Foundation[No.ZR2020QD016,No.ZR2022QD120].
文摘Evapotranspiration(ET)plays a crucial role in the global water and energy cycle.Upscaling instantaneous ET(ET_(i))to daily ET(ET_(d))is vital for thermal-based ET estimation.Conventional methods-such as the constant evaporative fraction method(ConEF),radiation-based method,and evaporative ratio method-often overlook environmental factors,leading to biased estimates of ET_(d)from ET_(i).To resolve this issue,this study aimed to assess four machine learning(ML)algorithms-XGBoost,LightGBM,AdaBoost,and Random Forest-to integrate meteorological and remote sensing data for upscaling ETi across 88 global flux sites.Each ML model was tested with eight different variable combinations.Results indicated that XGBoost exhibited the best performance,with a root mean square error(RMSE)generally below 13 W m^(-2)in estimating ET_(d)from ET_(i).The best variable combination simultaneously considers evaporative fraction,available energy,meteorology factors,remote sensing albedo,normalized vegetation index,and leaf area index.Using this combination,the XGBoost model achieved an R^(2)=0.88 and an RMSE=12.33 W m^(-2),outperforming the ConEF method(R^(2)=0.71 and RMSE=18.86 Wm^(-2))and its expansions.These findings support the application of ML models in ET upscaling,enabling ET estimation across large spatiotemporal scales.
文摘Among all the phase morphologies of poly(9,9-di-n-octylfluorenyl-2,7-diyl)(PFO),the𝛽phase exhibits a zigzag coplanar arrangement with the highest conjugation degree.As a result,the𝛽-phasePFO has extraordinary prop-erties,including enhanced charge carrier mobility.In this work,we report the formation of high-𝛽-phase PFO in nanoparticles(NPs)due to the synergistic effect of the slow crystallization of PFO in nanodroplet confinement and polystyrene(PS)blending.The𝛽-phase content of PFO can be flexibly tuned by varying the NP size,molec-ular weight(M w),or relative PS content in the NPs.The novel systems demonstrated in this study are likely to provide valuable insights into the𝛽-phase formation mechanism of PFO.As a proof of concept,we further demonstrate that NPs of PFO:PS(1:8)with a higher𝛽-phase content lead to improved photocatalyst efficiency at lower material costs,allowing for novel designs of efficient and visible-light-driven photocatalytic NPs.
