Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary ca...Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.展开更多
A dissolution test for fesoterodine low dose extended-release tablets using liquid chromatographic（LC） method equipped with a C18 monolithic column was developed and validated. LC system was operated isocratically a...A dissolution test for fesoterodine low dose extended-release tablets using liquid chromatographic（LC） method equipped with a C18 monolithic column was developed and validated. LC system was operated isocratically at controlled temperature（40 1C） using a mobile phase of acetonitrile：methanol：0.03 M ammonium acetate（p H 3.8）（30：15：55, v/v/v）, run at a flow rate of 1.5 m L/min and detected at 208 nm. The best dissolution conditions for this formulation were achieved using a USP apparatus 2（paddle） at 100 rpm and 900 m L of phosphate buffer at p H 6.8 as the dissolution medium.Validation parameters such as the specificity, linearity, accuracy, precision, and robustness were evaluated according to international guidelines, giving results within the acceptable range. The kinetic parameters of drug release were also investigated using model-dependent methods and the dissolution profiles were best described by the Higuchi model. The validated dissolution test can be applied for quality control of this formulation.展开更多
Four kinds of polymer coated urea(PCU)were put in distilled water at 30℃ to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU coul...Four kinds of polymer coated urea(PCU)were put in distilled water at 30℃ to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU could be divided into four stages: lag stage, swell stage, steady stage and decay stage. The release rate coefficient K, a measure of coating penetrability, was linearly increased at swell stage, but almost not variable at steady stage. At decay stage, the relation of X to time t could be described by the equation K= mtn-1where m and n are the coefficients). When n>1, the coating penetrability was gradually increased, and the urea release from PCU was accelerated; when n=1, the coating penetrability was steady, and the urea release from PCU obeyed the first-order kinetics; and when n<1.the coating penetrability was gradually decreased, and the urea release from PCU was delayed, resulting in a significant 'tailing effect'.展开更多
A soil–plant biological system was developed from chromium（Cr） polluted soil treated by the compost-phytoremediation method. The transformation and migration of the Cr in this system is comprehensively studied in t...A soil–plant biological system was developed from chromium（Cr） polluted soil treated by the compost-phytoremediation method. The transformation and migration of the Cr in this system is comprehensively studied in this research. The results illustrated that the co-composting treatment can reduce the Cr availability from 39%（F1 was about 31% of total, F2 was about 8% of total） to less than 2% by stabilizing the Cr. However, herbaceous plants can accumulate the concentrations of Cr from 113.8 to 265.2 mg/kg in the two crops,even though the concentration of soluble Cr in the substrate soil was below 0.1 mg/L.Cr can be assimilated and easily transferred in the tissues of plants because the lowmolecular-weight organic-acids（LMWOAs） derived from the plant root increase the bioavailability of Cr. The amount of extracted Cr dramatically increased when the organic acids were substituted in this order： citric acid 〉 malic acid 〉 tartaric acid 〉 oxalic acid 〉acetic acid. On average the maximum（147.4 mg/kg） and the minimum（78.75 mg/kg） Cr were extracted by 20 mmol/L citric acid and acetic acid, respectively. The desorption of Cr in different acid solutions can be predicted by the pseudo second-order kinetics. The exchangeable Cr, carbonate-bound Cr, and residual Cr decreased, while Fe–Mn oxide bound Cr and organic bound Cr increased in the soil solid phase. According to the experimental results, the organic acids will promote the desorption and chelation processes of Cr, leading to the remobilization of Cr in the soil.展开更多
Phosphate release from three selected soils after treatments of 1.6 and 2.4 mmol L-1 P was investigated using sequential extractions and fitted using six kinetic models, including zero order (Z), first order (F), seco...Phosphate release from three selected soils after treatments of 1.6 and 2.4 mmol L-1 P was investigated using sequential extractions and fitted using six kinetic models, including zero order (Z), first order (F), second order (S), parabolic diffusion (PD), two constant rate (TC), and Elovich type (ET) equations. The results showed that the rate of P release was initially rapid and then gradually declined with time. Also, P release increased with added P. Total P release followed the order: paddy soil with 2.4 mmol L-1 P > red soil with 2.4 mmol L-1 P > paddy soil with 1.6 mmol L-1 P > fluvo-aquic soil with 2.4 mmol L-1 P > fluvo-aquic with 1.6 mmol L-1 P > red soil with 1.6 mmol L-1 P. For the two P treatments P release from the paddy soils in the first extraction was 44.3% and 45.6% of total released P, respectively, which were higher than those from red and fluvo-aquic soils. The ratio of P release at the end of release time was 14.0% and 13.1% in the paddy soil treated with 1.6 and 2.4 mmol L-1 P, respectively, but only 5.1% and 9.2% in the red soil and 7.0% and 5.2% in the fluvo-aquic soil, respectively. Comparison of the coefficients of determination (R2) indicated that ET, TC, and PD equations could describe the P release data better than Z, F, and S equations.展开更多
It is essential to develop effective methods for the quality control of the traditional medicine with multiple components.However,few researches on the quality control have been conducted to interpret the holistic cha...It is essential to develop effective methods for the quality control of the traditional medicine with multiple components.However,few researches on the quality control have been conducted to interpret the holistic characteristics of the traditional medicine in terms of dissolution/release.In this study,the multi-component release kinetics of Traditional Chinese Medicine(TCM)dosage forms was characterized and mapped by multivariate analysis techniques in the field of‘‘-omics’’.The Liuweidihuang pill was used as a model formulation.The multi-component release kinetics of the concentrated and water-honeyed Liuweidihuang pills at rotation speeds of 50 and 100 rpm were analyzed by chemomic release kinetic theory and modified LC/MS/MS method.Mass features of 103(concentrated pills)and 101(water-honeyed pills)were selected with a linear correlation coefficient Z0.99 between mass responses and concentrations.To compose the chemomic standard spectrum,the relative abundance of both mass features was no less than 1%as compared with an internal standard.The correlation coefficients between six samples of various solutions were in line with analytical requirements of precision(rZ0.985).The score plots of principal component analysis showed that the concentrated Liuweidihuang pills presented better chemomic release reproducibility than the water-honeyed pills.Conversely,the impact of rotation speed on the chemomic release was less obvious.The heat maps of hierarchical clustering analysis did not show significant changes in individual clusters of mass features along different time intervals,reflecting the release integrity of the mass features.Therefore,both multivariate analysis methods,the principal component analysis and the hierarchical clustering analysis,seemed to be effective techniques to demonstrate the multiple component release performance of TCM.The research provided the basis of a new strategy for the quality control procedures of the dissolution/release for the traditional medicine and multi-component natural products to address increasing regulatory requirements and scrutiny across the world.展开更多
Although the protein content of swine diets is formulated based on the ileal digestibility of protein and amino acids(AA)under current nutrition requirements,the nitrogen utilization efficiency of swine varies based o...Although the protein content of swine diets is formulated based on the ileal digestibility of protein and amino acids(AA)under current nutrition requirements,the nitrogen utilization efficiency of swine varies based on protein source,which may be related to AA release kinetics.In this experiment,a 2×2 factorial arrangement with casein(CAS)-enriched or corn gluten meal(CGM)-enriched protein sources at different digestible crude protein levels(normal[N],13%;and low[L],11%)were applied to 24 crossbred(DurocLandraceYorkshire)growing pigs(average body weight=43.3±3.5 kg)in 4 treatments(N.CAS,L.CAS,N.CGM,L.CGM,respectively)to investigate the effects of AA release kinetics on nitrogen deposition in growing pigs.Standardized ileal digestible AA in all diets were balanced by adding individual AA to meet the nutrient requirements.The AA release kinetics were detected in vitro by measuring the hydrolysis of various protein diets under pepsin and trypsin conditions.The results demonstrated that the time of AA release peak in the CGM diet was 12 h later than that in the CAS diet.The synchronization indices of dietary AA release in N.CAS,N.CGM,L.CAS,and L.CGM were 23.73%,29.37%,23.40%,and 26.07%,respectively.The N.CGM had the poorest AA release synchronism while the N.CAS had the greatest among the 4 diets.However,within the pigs,L.CAS and N.CGM showed the highest(81.08%)and lowest(73.54%)nitrogen biological values,respectively,despite the standard ileal digestible AA levels being equal for all diets.These results indicate that the release kinetics of dietary AA had great effect on nitrogen deposition.To optimize nitrogen deposition,AA release kinetics and composition should be taken into consideration when formulating diets for growing pigs.展开更多
Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and c...Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and compressed into tablets by direct compression.Drug release kinetics from tablets withdifferent compositions was investigated in vitro.Results showed that dissolution process of NMDP from poroushydrophilic matrix conformed to zero-order release kinetics.The addition of microcrystalline cellulose to the porousswellable release system increased the NMDP release rate constant.The presence of hydroxyethylcellulose(HEC)inthe system,which had a lower viscosity,increased the drug release rate constant.When tablets were prepared withHPMC 40 mesh granulation,the release rate of the drug was sustained.These show that the dosage form may beformulated as a drug-polymer system with constant release at a desired rate.The release properties of the sustainedrelease tablets made by pure drug instead of drug solid dispersion were also investigated.In the present study,theoptimal formulations that constantly released the drug during 12 h were selected for in vivo analysis.展开更多
Background Promoting the synchronization of glucose and amino acid release in the digestive tract of pigs could effectively improve dietary nitrogen utilization.The rational allocation of dietary starch sources and th...Background Promoting the synchronization of glucose and amino acid release in the digestive tract of pigs could effectively improve dietary nitrogen utilization.The rational allocation of dietary starch sources and the exploration of appropriate dietary glucose release kinetics may promote the dynamic balance of dietary glucose and amino acid supplies.However,research on the effects of diets with different glucose release kinetic profiles on amino acid absorption and portal amino acid appearance in piglets is limited.This study aimed to investigate the effects of the kinetic pattern of dietary glucose release on nitrogen utilization,the portal amino acid profile,and nutrient transporter expression in intestinal enterocytes in piglets.Methods Sixty-four barrows(15.00±1.12 kg)were randomly allotted to 4 groups and fed diets formulated with starch from corn,corn/barley,corn/sorghum,or corn/cassava combinations(diets were coded A,B,C,or D respectively).Protein retention,the concentrations of portal amino acid and glucose,and the relative expression of amino acid and glucose transporter m RNAs were investigated.In vitro digestion was used to compare the dietary glucose release profiles.Results Four piglet diets with different glucose release kinetics were constructed by adjusting starch sources.The in vivo appearance dynamics of portal glucose were consistent with those of in vitro dietary glucose release kinetics.Total nitrogen excretion was reduced in the piglets in group B,while apparent nitrogen digestibility and nitrogen retention increased(P<0.05).Regardless of the time(2 h or 4 h after morning feeding),the portal total free amino acids content and contents of some individual amino acids(Thr,Glu,Gly,Ala,and Ile)of the piglets in group B were significantly higher than those in groups A,C,and D(P<0.05).Cluster analysis showed that different glucose release kinetic patterns resulted in different portal amino acid patterns in piglets,which decreased gradually with the extension of feeding time.The portal His/Phe,Pro/Glu,Leu/Val,Lys/Met,Tyr/Ile and Ala/Gly appeared higher similarity among the diet treatments.In the anterior jejunum,the glucose transporter SGLT1 was significantly positively correlated with the amino acid transporters B0AT1,EAAC1,and CAT1.Conclusions Rational allocation of starch resources could regulate dietary glucose release kinetics.In the present study,group B(corn/barley)diet exhibited a better glucose release kinetic pattern than the other groups,which could affect the portal amino acid contents and patterns by regulating the expression of amino acid transporters in the small intestine,thereby promoting nitrogen deposition in the body,and improving the utilization efficiency of dietary nitrogen.展开更多
This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer （UCRF） and the N uptake and N-use efficiency by rice plants. Water dissolution, soil le...This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer （UCRF） and the N uptake and N-use efficiency by rice plants. Water dissolution, soil leaching, and pot experiments were employed. The dynamics of N release from the UCRF could be quantitatively described by three equations： the first-order kinetics equation [N1=N0 （1-e^-kt）], Elovich equation （N1=a ＋ blnt）, and parabola equation （N1=a ＋ bt^0.5）, with the best fitting by the first-order kinetics equation for different N （r= 0.9569^＊＊-0.9999^＊＊）. The release potentials （No values estimated by the first-order kinetics equation） of different N in the UCRF decreased in the order of total N 〉 DON 〉 urea-N 〉 NH4^＋-N 〉 NO3^-N in water, and total N 〉 NH4^＋-N 〉 DON 〉 urea-N 〉 NO3^--N in soil, respectively, being in accordance with cumulative amounts of N release. The constants of N release rate （k values and b values） for different N forms were in decreasing order of total N 〉 DON 〉 NH4^＋-N 〉 NO3^--N in water, whereas the k values were urea- N 〉DON 〉 NH4^＋-N 〉 total N 〉 NO3^--N, and the b values were total N 〉 NH4^＋-N 〉 DON 〉 NO3^--N 〉 urea-N in soil. Compared with a common compound fertilizer, the N-use efficiency, N-agronomy efficiency, and N-physiological efficiency of the UCRF were increased by 11.4%, 8.32 kg kg^-1, and 5.17 kg kg^-1, respectively. The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants. The findings showed that the first-order kinetics equation [Nt=N0 （l-e^kt）] could be used to describe the release characteristics of different N forms in the fertilizer. The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.展开更多
In this study,chlorogenic acid(CGA),a phenolic compound widely distributed in fruits and vegetables,was encapsulated into chitosan nanoparticles by ionic gelation method.The particles exhibited the size and zeta poten...In this study,chlorogenic acid(CGA),a phenolic compound widely distributed in fruits and vegetables,was encapsulated into chitosan nanoparticles by ionic gelation method.The particles exhibited the size and zeta potential of 210 nm and 33 mV respectively.A regular,spherical shaped distribution of nanoparticles was observed through scanning electron microscopy(SEM)and the success of entrapment was confirmed by FTIR analysis.The encapsulation efficiency of CGA was at about 59%with the loading efficiency of 5.2%.In vitro ABTS assay indicated that the radical scavenging activity of CAG was retained in the nanostructure and further,the release kinetics study revealed the burst release of 69%CGA from nanoparticles at the end of 100th hours.Pharmacokinetic analysis in rats showed a lower level of Cmax,longer Tmax,longer MRT,larger AUC0et and AUC0e∞for the CGA nanoparticles compared to free CGA.Collectively,these results suggest that the synthesised nanoparticle with sustained release property can therefore ease the fortification of food-matrices targeted for health benefits through effective delivery of CGA in body.展开更多
Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feas...Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.展开更多
Changes in solution chemistry and transport conditions can lead to the release of deposited MnO2 nanoparticles from a solid interface,allowing them to re-enter the aqueous environment.Understanding the release behavio...Changes in solution chemistry and transport conditions can lead to the release of deposited MnO2 nanoparticles from a solid interface,allowing them to re-enter the aqueous environment.Understanding the release behavior of Mn02 nanoparticles from naturally occurring surfaces is critical for better prediction of the transport potential and environmental fate of Mn02 nanoparticles.In this study,the release of Mn02 nanoparticles was investigated using a quartz crystal microbalance with dissipation monitoring(QCM-D),and different environmental surface types,solution pH values and representative macromolecular organics were considered.Mn02 nanoparticles were first deposited on crystal sensors at elevated NaN03 concentrations before being rinsed with double-deionized water to induce their remobilization.The results reveal that the release rate of Mn02 depends on the surface type,in the decreasing order:SiO2>Fe304>Al2 O3,resulting from electrostatic interactions between the surface and particles.Moreover,differences in solution pH can lead to variance in the release behavior of Mn02 nanoparticles.The release rate from surfaces was significantly higher at pH 9.8 that at 4.5,indicating that alkaline conditions were more favorable for the mobilization of Mn02 in the aquatic environment.In the presence of macromolecular organics,bovine serum albumin(BSA)can inhibit the release of Mn02 from the surfaces due to attractive forces.In presence of humic acid(HA)and sodium alginate(SA),the Mn02 nanoparticles were more likely to be mobile,which may be associated with a large repulsive barrier imparted by steric effects.展开更多
The low utilization rate of pesticides makes the migration of pesticides in water and soil,which brings great harm to the ecosystem.The development of pesticide carriers with good drug loading capacity and release con...The low utilization rate of pesticides makes the migration of pesticides in water and soil,which brings great harm to the ecosystem.The development of pesticide carriers with good drug loading capacity and release control abil-ity is an effective method to realize effective utilization of pesticides and reduce pesticide losses.In this work,fosthiazate-stearic acid/expanded perlite sustained-release particles were successfully prepared by vacuum impregnation using expanded perlite(EP)as carrier,fosthiazate(FOS)as model pesticide and stearic acid(SA)as hydrophobic matrix.The structure and morphology of the samples were studied by BET,FT-IR,TGA,XRD,DSC and SEM.The effects of different mass ratios of FOS to SA on loading capacity and release rate at 24 h were investigated.The sustained release behavior of FOS-SA/EP at different temperatures and pH values was investigated by static dialysis bag method.The results showed that FOS and SA were adsorbed in EP pores by physical interaction.With the mass ratios of FOS to SA decreasing from 7:3 to 3:7,the 24 h release rate of FOS-SA/EP decreased from 18.77%to 8.05%,and the drug loading decreased from 461.32 to 130.99 mg/g.FOS-SA/EP showed obvious temperature response at 25℃,30℃ and 35℃,the cumulative release rate(CRR)of 200 h were 33.38%,41.50%and 51.17%,respectively.When pH=5,the CRR of FOS was higher than that of pH=7,and the CRR of FOS for 200 h were 49.01%and 30.12%,respectively.At different temperatures and pH=5,the release mechanism of FOS-SA/EP belongs to the Fickian diffusion mechanism;When pH=7,the diffusion mechanism is dominant,and the dissolution mechanism is complementary.展开更多
The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coin...The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coincidence,and their momentum vectors are determined by employing a reaction microscope.The complete kinematical information of four two-body fragmentation channels of H^(+)+OH+,H^(+)+OD^(+),D^(+)+OH^(+),and D^(+)+OD+is obtained.By analyzing the projectile energy-loss spectrum,the initial electronic state of the two-body dissociation channel is determined.Upon examining the kinetic energy release(KER)distributions of the four fragmentation channels,a clear difference is found between the two-body fragmentation channel H^(+)+OD+and the other three channels.The isotopic effect in the two-body fragmentation is demonstrated by the analysis of the relative yields of the two-body fragmentation channels originating from different isotopologues,which shows preferential cleavage of the O-H bond over the O-D bond.These results provide deeper insight into the microscopic dynamic mechanisms in water radiolysis.展开更多
The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acryli...The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acrylic acid with different cross linking agents were synthesised.Drug-resin complexes(DRCs)with three different ratios of drug to IERs(1:1,1:2,1:4)were prepared&evaluated for taste masking by following in vivo and in vitro methods.Human volunteers graded ADC 1:4,acrylic acid-divinyl benzene(ADC-3)resin as tasteless.Characterization studies such as FTIR,SEM,DSC,P-XRD differentiated ADC 1:4,from physical mixture(PM 1:4)and confirmed the formation of complex.In vitro drug release of ADC 1:4 showed complete release of CP within 60 min at simulated gastric fluid(SGF)i.e.pH 1.2.IPN beads were prepared with ADC 1:4 by using sodium alginate(AL)and sodium alginate-chitosan(AL-CS)for sustain release of CP at SGF pH and followed by simulated intestinal fluid(SIF i.e.pH 7.4).FTIR spectra confirmed the formation of IPN beads.The release of CP was sustain at SGF pH(<20%)whereas in SIF media it was more(>75%).The kinetic model of IPN beads showed the release of CP was non-Fickian diffusion type.展开更多
A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated....A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated. The addition of glutaraldehyde and α-tocopherol decreased the lightness and greenness and increased the yellowness of the chitosan-based film. Moreover, it also affected the compatibility of the film due to a decrease in the opacity values. The elongation at break(EB) and tensile strength(TS) values of the film decreased when the glutaraldehyde and α-tocopherol were added. In contrast, the Young’s modulus(YM) values increased. SEM micrographs showed coarse spots and pores on the surface and cross-section of the film when compared with the chitosan film. Based on the results, it was indicated that the chitosan structure was disconnected by the α-tocopherol, and the glutaraldehyde as a crosslinking agent generated a link between the chitosan network, which could be the cause of the reduced flexibility and the increased surface roughness of the film. However, the glutaraldehyde and α-tocopherol did not result in a significant difference in water vapour permeability(WVP) values. The glutaraldehyde influenced the release kinetics of the α-tocopherol as seen by the decrease of the diffusion coefficient values that were calculated using the Fickian diffusion model.展开更多
Although therapeutic potential of neurotrophic factors(NTFs)has been well recognized for over two decades,attempts to translate that potential to the clinic have been disappointing,largely due to significant obstacle...Although therapeutic potential of neurotrophic factors(NTFs)has been well recognized for over two decades,attempts to translate that potential to the clinic have been disappointing,largely due to significant obstacles in delivery,including inadequate protein dose/kinetics released at target sites.Considerable efforts have been made to improve the therapeutic performance of NTFs.This articles reviews recent developments in localized delivery systems of NTFs for the neurological disorders treatments with a main focus on sustained delivery strategies.Different non-covalent binding approaches have been employed to immobilize proteins in hydrogels,microspheres,electrospun nanofibers,and their combined systems,which serve as depots for sustained local release of NTFs.The challenges associated with current NTFs delivery systems and how these systems can be applied to neurological diseases and disorders have been discussed in the review.In conclusion,optimal delivery systems for NTFs will be needed for reliable and meaningful clinical benefits;ideally,delivering a time and dose-controlled release of bioactive multiNTFs at different individual optimal kinetics to achieve multi-functions in target tissues is significant preferred.展开更多
Biochar has been shown to be an effective organic soil amendment for the in-situ immobilization of lead(Pb).Little research has been done on the effects of biochar and zeolite interactions on Pb immobilization in cont...Biochar has been shown to be an effective organic soil amendment for the in-situ immobilization of lead(Pb).Little research has been done on the effects of biochar and zeolite interactions on Pb immobilization in contaminated calcareous soils.Therefore,the aim of this study was to investigate the effects of different levels of zeolite(2%and 4%,weight:weight)and biochars(3%,weight:weight)prepared from green compost(GB),poultry manure(PB),and municipal waste(MB)on the content of Pb in spinach shoots and Pb stabilization in a greenhouse experiment conducted using a Pb-contaminated calcareous soil.Application of GB and PB significantly decreased the Pb mobility factor(MF)from 2.8%to 4.6%and the cumulative Pb release(diethylenetriamine pentaacetate(DTPA)extraction)from 16.8%to 20.1%in the calcareous soil,which were further enhanced by the combined addition of zeolite,with Pb MF reduction from 4.4%to 8.4%and cumulative Pb release reduction from 24.8%to 28.6%.The enhancement of soil Pb immobilization was attributed to the properties of the amendments,such as high pH,ash content,and phosphorus content(10.5^(-1)1.0,390-435 g kg^(-1),and 2.5-4.3 g kg^(-1),respectively).Results of the soil Pb sequential extraction and Pb release kinetics were highly and significantly correlated with spinach shoot Pb content.Soil chemical data showed that the application of MB with 4%zeolite was the most effective treatment for immobilizing Pb(8.4%reduction in Pb MF and 28.6%reduction in cumulative DTPA-extractable Pb),which is in agreement with the results of the spinach shoot Pb(89.0%reduction in Pb uptake).展开更多
<strong>Background: </strong>Recent decades witnessed a significant growth in terms of phytocompounds based therapeutics, extensively explored for almost all types of existing disorders. They have also bee...<strong>Background: </strong>Recent decades witnessed a significant growth in terms of phytocompounds based therapeutics, extensively explored for almost all types of existing disorders. They have also been widely investigated in Neurodegenerative disorders (NDDs) and Chlorogenic acid (CGA), a polyphenolic compound having potential anti-inflammatory and anti-oxidative properties, emerged as a promising compound in ameliorating NDDs. Owing to its poor stability, bioavailability and release kinetics, CGA needed a suitable nanocarrier based pharmaceutical design for targeting NDDs. <strong>Objective: </strong>The current study is aimed at the <em>in-silico</em> validation of CGA as an effective therapeutic agent targeting various NDDs followed by the fabrication of polymeric nanoparticles-based carrier system to overcome its pharmacological limitations and improve its stability. <strong>Methods:</strong> A successful <em>in-silico</em> validation using molecular docking techniques along with synthesis of CGA loaded polymeric nanoparticles (CGA-NPs) by ionic gelation method was performed. The statistical optimisation of the developed CGA-NPs was done by Box Behnken method and then the optimized formulation of CGA-NPs was characterised using particle size analysis (PSA), Transmission electron microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR) along with in-vitro release kinetics analysis.<strong> Results & Conclusion:</strong> The results attained exhibited average particle size of 101.9 ± 1.5 nm, Polydispersibility (PDI) score of 0.065 and a ZP of <span style="white-space:nowrap;">−</span>17.4 mV. On a similar note, TEM results showed a size range of CGA-NPs between 90 - 110 nm with a spherical shape of NPs. Also, the data from in-vitro release kinetics showed a sustained release of CGA from the NPs following the first-order kinetics suggesting the appropriate designing of nanoformulation.展开更多
基金supported by the National Key Research and Development Program of China(2021YFD1300201)the National Natural Science Foundation of China(32330100 and 32125036)+3 种基金the China Agricultural Research System(CARS-35)2115 Talent Development Program of China Agricultural Universitythe 111 Project(No.B16044)the 2023 Key Project of the Graduate Independent Innovation Research Fund at China Agricultural University。
文摘Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.
基金CAPES(Coordenacao de Aperfeicoamento de Pessoal de Nível Superior)FAPERJ(Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro)for the financial support
文摘A dissolution test for fesoterodine low dose extended-release tablets using liquid chromatographic（LC） method equipped with a C18 monolithic column was developed and validated. LC system was operated isocratically at controlled temperature（40 1C） using a mobile phase of acetonitrile：methanol：0.03 M ammonium acetate（p H 3.8）（30：15：55, v/v/v）, run at a flow rate of 1.5 m L/min and detected at 208 nm. The best dissolution conditions for this formulation were achieved using a USP apparatus 2（paddle） at 100 rpm and 900 m L of phosphate buffer at p H 6.8 as the dissolution medium.Validation parameters such as the specificity, linearity, accuracy, precision, and robustness were evaluated according to international guidelines, giving results within the acceptable range. The kinetic parameters of drug release were also investigated using model-dependent methods and the dissolution profiles were best described by the Higuchi model. The validated dissolution test can be applied for quality control of this formulation.
基金supported by the National 863 Program,Ministry of Science and Technology of China(2001AA246021)the Knowledge Innovation Engineering of the Chinese Academy of Sciences(KZCX2-402).
文摘Four kinds of polymer coated urea(PCU)were put in distilled water at 30℃ to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU could be divided into four stages: lag stage, swell stage, steady stage and decay stage. The release rate coefficient K, a measure of coating penetrability, was linearly increased at swell stage, but almost not variable at steady stage. At decay stage, the relation of X to time t could be described by the equation K= mtn-1where m and n are the coefficients). When n>1, the coating penetrability was gradually increased, and the urea release from PCU was accelerated; when n=1, the coating penetrability was steady, and the urea release from PCU obeyed the first-order kinetics; and when n<1.the coating penetrability was gradually decreased, and the urea release from PCU was delayed, resulting in a significant 'tailing effect'.
基金supported by the National Natural Science Foundation of China (Nos. 21376251 and 21406233)the National Basic Research Program (973) of China (No. 2013CB632600)
文摘A soil–plant biological system was developed from chromium（Cr） polluted soil treated by the compost-phytoremediation method. The transformation and migration of the Cr in this system is comprehensively studied in this research. The results illustrated that the co-composting treatment can reduce the Cr availability from 39%（F1 was about 31% of total, F2 was about 8% of total） to less than 2% by stabilizing the Cr. However, herbaceous plants can accumulate the concentrations of Cr from 113.8 to 265.2 mg/kg in the two crops,even though the concentration of soluble Cr in the substrate soil was below 0.1 mg/L.Cr can be assimilated and easily transferred in the tissues of plants because the lowmolecular-weight organic-acids（LMWOAs） derived from the plant root increase the bioavailability of Cr. The amount of extracted Cr dramatically increased when the organic acids were substituted in this order： citric acid 〉 malic acid 〉 tartaric acid 〉 oxalic acid 〉acetic acid. On average the maximum（147.4 mg/kg） and the minimum（78.75 mg/kg） Cr were extracted by 20 mmol/L citric acid and acetic acid, respectively. The desorption of Cr in different acid solutions can be predicted by the pseudo second-order kinetics. The exchangeable Cr, carbonate-bound Cr, and residual Cr decreased, while Fe–Mn oxide bound Cr and organic bound Cr increased in the soil solid phase. According to the experimental results, the organic acids will promote the desorption and chelation processes of Cr, leading to the remobilization of Cr in the soil.
基金Project supported by the National Natural Science Foundation of China (No. 40071051) and the National Key BasicResearch Support Foundation of China (No. G1999011802).
文摘Phosphate release from three selected soils after treatments of 1.6 and 2.4 mmol L-1 P was investigated using sequential extractions and fitted using six kinetic models, including zero order (Z), first order (F), second order (S), parabolic diffusion (PD), two constant rate (TC), and Elovich type (ET) equations. The results showed that the rate of P release was initially rapid and then gradually declined with time. Also, P release increased with added P. Total P release followed the order: paddy soil with 2.4 mmol L-1 P > red soil with 2.4 mmol L-1 P > paddy soil with 1.6 mmol L-1 P > fluvo-aquic soil with 2.4 mmol L-1 P > fluvo-aquic with 1.6 mmol L-1 P > red soil with 1.6 mmol L-1 P. For the two P treatments P release from the paddy soils in the first extraction was 44.3% and 45.6% of total released P, respectively, which were higher than those from red and fluvo-aquic soils. The ratio of P release at the end of release time was 14.0% and 13.1% in the paddy soil treated with 1.6 and 2.4 mmol L-1 P, respectively, but only 5.1% and 9.2% in the red soil and 7.0% and 5.2% in the fluvo-aquic soil, respectively. Comparison of the coefficients of determination (R2) indicated that ET, TC, and PD equations could describe the P release data better than Z, F, and S equations.
基金This work was supported by the Shanghai Science and Technology Development Funds(No.09dZ1973300)Key Projects in the National Science&Technology Pillar Program(No.2009ZX09304-003).
文摘It is essential to develop effective methods for the quality control of the traditional medicine with multiple components.However,few researches on the quality control have been conducted to interpret the holistic characteristics of the traditional medicine in terms of dissolution/release.In this study,the multi-component release kinetics of Traditional Chinese Medicine(TCM)dosage forms was characterized and mapped by multivariate analysis techniques in the field of‘‘-omics’’.The Liuweidihuang pill was used as a model formulation.The multi-component release kinetics of the concentrated and water-honeyed Liuweidihuang pills at rotation speeds of 50 and 100 rpm were analyzed by chemomic release kinetic theory and modified LC/MS/MS method.Mass features of 103(concentrated pills)and 101(water-honeyed pills)were selected with a linear correlation coefficient Z0.99 between mass responses and concentrations.To compose the chemomic standard spectrum,the relative abundance of both mass features was no less than 1%as compared with an internal standard.The correlation coefficients between six samples of various solutions were in line with analytical requirements of precision(rZ0.985).The score plots of principal component analysis showed that the concentrated Liuweidihuang pills presented better chemomic release reproducibility than the water-honeyed pills.Conversely,the impact of rotation speed on the chemomic release was less obvious.The heat maps of hierarchical clustering analysis did not show significant changes in individual clusters of mass features along different time intervals,reflecting the release integrity of the mass features.Therefore,both multivariate analysis methods,the principal component analysis and the hierarchical clustering analysis,seemed to be effective techniques to demonstrate the multiple component release performance of TCM.The research provided the basis of a new strategy for the quality control procedures of the dissolution/release for the traditional medicine and multi-component natural products to address increasing regulatory requirements and scrutiny across the world.
基金the National Natural Science Foundation of China(No.31572439 and No.31572415)the Natural Science Foundation of Jilin Province of China(No.20160101348JC)the Key technology research and development program of Jilin Province of China(No.20180201018NY).
文摘Although the protein content of swine diets is formulated based on the ileal digestibility of protein and amino acids(AA)under current nutrition requirements,the nitrogen utilization efficiency of swine varies based on protein source,which may be related to AA release kinetics.In this experiment,a 2×2 factorial arrangement with casein(CAS)-enriched or corn gluten meal(CGM)-enriched protein sources at different digestible crude protein levels(normal[N],13%;and low[L],11%)were applied to 24 crossbred(DurocLandraceYorkshire)growing pigs(average body weight=43.3±3.5 kg)in 4 treatments(N.CAS,L.CAS,N.CGM,L.CGM,respectively)to investigate the effects of AA release kinetics on nitrogen deposition in growing pigs.Standardized ileal digestible AA in all diets were balanced by adding individual AA to meet the nutrient requirements.The AA release kinetics were detected in vitro by measuring the hydrolysis of various protein diets under pepsin and trypsin conditions.The results demonstrated that the time of AA release peak in the CGM diet was 12 h later than that in the CAS diet.The synchronization indices of dietary AA release in N.CAS,N.CGM,L.CAS,and L.CGM were 23.73%,29.37%,23.40%,and 26.07%,respectively.The N.CGM had the poorest AA release synchronism while the N.CAS had the greatest among the 4 diets.However,within the pigs,L.CAS and N.CGM showed the highest(81.08%)and lowest(73.54%)nitrogen biological values,respectively,despite the standard ileal digestible AA levels being equal for all diets.These results indicate that the release kinetics of dietary AA had great effect on nitrogen deposition.To optimize nitrogen deposition,AA release kinetics and composition should be taken into consideration when formulating diets for growing pigs.
文摘Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and compressed into tablets by direct compression.Drug release kinetics from tablets withdifferent compositions was investigated in vitro.Results showed that dissolution process of NMDP from poroushydrophilic matrix conformed to zero-order release kinetics.The addition of microcrystalline cellulose to the porousswellable release system increased the NMDP release rate constant.The presence of hydroxyethylcellulose(HEC)inthe system,which had a lower viscosity,increased the drug release rate constant.When tablets were prepared withHPMC 40 mesh granulation,the release rate of the drug was sustained.These show that the dosage form may beformulated as a drug-polymer system with constant release at a desired rate.The release properties of the sustainedrelease tablets made by pure drug instead of drug solid dispersion were also investigated.In the present study,theoptimal formulations that constantly released the drug during 12 h were selected for in vivo analysis.
基金partially supported by the National Key Research and Development Program of China(2021YFD1300201)Jilin Province Key Research and Development Program of China(20220202044NC)。
文摘Background Promoting the synchronization of glucose and amino acid release in the digestive tract of pigs could effectively improve dietary nitrogen utilization.The rational allocation of dietary starch sources and the exploration of appropriate dietary glucose release kinetics may promote the dynamic balance of dietary glucose and amino acid supplies.However,research on the effects of diets with different glucose release kinetic profiles on amino acid absorption and portal amino acid appearance in piglets is limited.This study aimed to investigate the effects of the kinetic pattern of dietary glucose release on nitrogen utilization,the portal amino acid profile,and nutrient transporter expression in intestinal enterocytes in piglets.Methods Sixty-four barrows(15.00±1.12 kg)were randomly allotted to 4 groups and fed diets formulated with starch from corn,corn/barley,corn/sorghum,or corn/cassava combinations(diets were coded A,B,C,or D respectively).Protein retention,the concentrations of portal amino acid and glucose,and the relative expression of amino acid and glucose transporter m RNAs were investigated.In vitro digestion was used to compare the dietary glucose release profiles.Results Four piglet diets with different glucose release kinetics were constructed by adjusting starch sources.The in vivo appearance dynamics of portal glucose were consistent with those of in vitro dietary glucose release kinetics.Total nitrogen excretion was reduced in the piglets in group B,while apparent nitrogen digestibility and nitrogen retention increased(P<0.05).Regardless of the time(2 h or 4 h after morning feeding),the portal total free amino acids content and contents of some individual amino acids(Thr,Glu,Gly,Ala,and Ile)of the piglets in group B were significantly higher than those in groups A,C,and D(P<0.05).Cluster analysis showed that different glucose release kinetic patterns resulted in different portal amino acid patterns in piglets,which decreased gradually with the extension of feeding time.The portal His/Phe,Pro/Glu,Leu/Val,Lys/Met,Tyr/Ile and Ala/Gly appeared higher similarity among the diet treatments.In the anterior jejunum,the glucose transporter SGLT1 was significantly positively correlated with the amino acid transporters B0AT1,EAAC1,and CAT1.Conclusions Rational allocation of starch resources could regulate dietary glucose release kinetics.In the present study,group B(corn/barley)diet exhibited a better glucose release kinetic pattern than the other groups,which could affect the portal amino acid contents and patterns by regulating the expression of amino acid transporters in the small intestine,thereby promoting nitrogen deposition in the body,and improving the utilization efficiency of dietary nitrogen.
文摘This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer （UCRF） and the N uptake and N-use efficiency by rice plants. Water dissolution, soil leaching, and pot experiments were employed. The dynamics of N release from the UCRF could be quantitatively described by three equations： the first-order kinetics equation [N1=N0 （1-e^-kt）], Elovich equation （N1=a ＋ blnt）, and parabola equation （N1=a ＋ bt^0.5）, with the best fitting by the first-order kinetics equation for different N （r= 0.9569^＊＊-0.9999^＊＊）. The release potentials （No values estimated by the first-order kinetics equation） of different N in the UCRF decreased in the order of total N 〉 DON 〉 urea-N 〉 NH4^＋-N 〉 NO3^-N in water, and total N 〉 NH4^＋-N 〉 DON 〉 urea-N 〉 NO3^--N in soil, respectively, being in accordance with cumulative amounts of N release. The constants of N release rate （k values and b values） for different N forms were in decreasing order of total N 〉 DON 〉 NH4^＋-N 〉 NO3^--N in water, whereas the k values were urea- N 〉DON 〉 NH4^＋-N 〉 total N 〉 NO3^--N, and the b values were total N 〉 NH4^＋-N 〉 DON 〉 NO3^--N 〉 urea-N in soil. Compared with a common compound fertilizer, the N-use efficiency, N-agronomy efficiency, and N-physiological efficiency of the UCRF were increased by 11.4%, 8.32 kg kg^-1, and 5.17 kg kg^-1, respectively. The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants. The findings showed that the first-order kinetics equation [Nt=N0 （l-e^kt）] could be used to describe the release characteristics of different N forms in the fertilizer. The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.
基金supported by DRDO,India.The authors are also thankful to the Director,DFRL,and Mysore for providing technical support and valuable suggestions.
文摘In this study,chlorogenic acid(CGA),a phenolic compound widely distributed in fruits and vegetables,was encapsulated into chitosan nanoparticles by ionic gelation method.The particles exhibited the size and zeta potential of 210 nm and 33 mV respectively.A regular,spherical shaped distribution of nanoparticles was observed through scanning electron microscopy(SEM)and the success of entrapment was confirmed by FTIR analysis.The encapsulation efficiency of CGA was at about 59%with the loading efficiency of 5.2%.In vitro ABTS assay indicated that the radical scavenging activity of CAG was retained in the nanostructure and further,the release kinetics study revealed the burst release of 69%CGA from nanoparticles at the end of 100th hours.Pharmacokinetic analysis in rats showed a lower level of Cmax,longer Tmax,longer MRT,larger AUC0et and AUC0e∞for the CGA nanoparticles compared to free CGA.Collectively,these results suggest that the synthesised nanoparticle with sustained release property can therefore ease the fortification of food-matrices targeted for health benefits through effective delivery of CGA in body.
基金supported by the "Applied Research and Multi-sectorial Program" (FIAM) (No. 5.2.1) granted by the Italian Cooperation and Development Agency (ICDA) to the Universidade Eduardo Mondlanethe Polytechnic University of Marche, Italy for the PhD scholarship provided to the first author as well as research funding for this work
文摘Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.
基金financially supported by the National Natural Science Foundation of China(Nos.51878092,51608067)the Scientific and Technological Innovation Special Program of Social Livelihood of Chongqing(No.cstc2015shmsztzx0053)the Fundamental Research Funds for the Central Universities(No.2019CDXYCH0026)
文摘Changes in solution chemistry and transport conditions can lead to the release of deposited MnO2 nanoparticles from a solid interface,allowing them to re-enter the aqueous environment.Understanding the release behavior of Mn02 nanoparticles from naturally occurring surfaces is critical for better prediction of the transport potential and environmental fate of Mn02 nanoparticles.In this study,the release of Mn02 nanoparticles was investigated using a quartz crystal microbalance with dissipation monitoring(QCM-D),and different environmental surface types,solution pH values and representative macromolecular organics were considered.Mn02 nanoparticles were first deposited on crystal sensors at elevated NaN03 concentrations before being rinsed with double-deionized water to induce their remobilization.The results reveal that the release rate of Mn02 depends on the surface type,in the decreasing order:SiO2>Fe304>Al2 O3,resulting from electrostatic interactions between the surface and particles.Moreover,differences in solution pH can lead to variance in the release behavior of Mn02 nanoparticles.The release rate from surfaces was significantly higher at pH 9.8 that at 4.5,indicating that alkaline conditions were more favorable for the mobilization of Mn02 in the aquatic environment.In the presence of macromolecular organics,bovine serum albumin(BSA)can inhibit the release of Mn02 from the surfaces due to attractive forces.In presence of humic acid(HA)and sodium alginate(SA),the Mn02 nanoparticles were more likely to be mobile,which may be associated with a large repulsive barrier imparted by steric effects.
基金supported by the Guangdong Provincial Science and Technology Project(No.2015B020215012)State Key Laboratory of Woody Oil Resource Utilization,Co-Built by Provincial and Ministry of China(No.GZKF202108)National Natural Science Foundation of China(32101475).
文摘The low utilization rate of pesticides makes the migration of pesticides in water and soil,which brings great harm to the ecosystem.The development of pesticide carriers with good drug loading capacity and release control abil-ity is an effective method to realize effective utilization of pesticides and reduce pesticide losses.In this work,fosthiazate-stearic acid/expanded perlite sustained-release particles were successfully prepared by vacuum impregnation using expanded perlite(EP)as carrier,fosthiazate(FOS)as model pesticide and stearic acid(SA)as hydrophobic matrix.The structure and morphology of the samples were studied by BET,FT-IR,TGA,XRD,DSC and SEM.The effects of different mass ratios of FOS to SA on loading capacity and release rate at 24 h were investigated.The sustained release behavior of FOS-SA/EP at different temperatures and pH values was investigated by static dialysis bag method.The results showed that FOS and SA were adsorbed in EP pores by physical interaction.With the mass ratios of FOS to SA decreasing from 7:3 to 3:7,the 24 h release rate of FOS-SA/EP decreased from 18.77%to 8.05%,and the drug loading decreased from 461.32 to 130.99 mg/g.FOS-SA/EP showed obvious temperature response at 25℃,30℃ and 35℃,the cumulative release rate(CRR)of 200 h were 33.38%,41.50%and 51.17%,respectively.When pH=5,the CRR of FOS was higher than that of pH=7,and the CRR of FOS for 200 h were 49.01%and 30.12%,respectively.At different temperatures and pH=5,the release mechanism of FOS-SA/EP belongs to the Fickian diffusion mechanism;When pH=7,the diffusion mechanism is dominant,and the dissolution mechanism is complementary.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12325406,92261201,12404305,11974272)the Shannxi Province Natural Science Fundamental Research Project(Grant Nos.2023JC-XJ-03 and 23JSQ013)the Fundamental Research Funds for the Central Universities(Grant No.xzy022024040)。
文摘The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coincidence,and their momentum vectors are determined by employing a reaction microscope.The complete kinematical information of four two-body fragmentation channels of H^(+)+OH+,H^(+)+OD^(+),D^(+)+OH^(+),and D^(+)+OD+is obtained.By analyzing the projectile energy-loss spectrum,the initial electronic state of the two-body dissociation channel is determined.Upon examining the kinetic energy release(KER)distributions of the four fragmentation channels,a clear difference is found between the two-body fragmentation channel H^(+)+OD+and the other three channels.The isotopic effect in the two-body fragmentation is demonstrated by the analysis of the relative yields of the two-body fragmentation channels originating from different isotopologues,which shows preferential cleavage of the O-H bond over the O-D bond.These results provide deeper insight into the microscopic dynamic mechanisms in water radiolysis.
文摘The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acrylic acid with different cross linking agents were synthesised.Drug-resin complexes(DRCs)with three different ratios of drug to IERs(1:1,1:2,1:4)were prepared&evaluated for taste masking by following in vivo and in vitro methods.Human volunteers graded ADC 1:4,acrylic acid-divinyl benzene(ADC-3)resin as tasteless.Characterization studies such as FTIR,SEM,DSC,P-XRD differentiated ADC 1:4,from physical mixture(PM 1:4)and confirmed the formation of complex.In vitro drug release of ADC 1:4 showed complete release of CP within 60 min at simulated gastric fluid(SGF)i.e.pH 1.2.IPN beads were prepared with ADC 1:4 by using sodium alginate(AL)and sodium alginate-chitosan(AL-CS)for sustain release of CP at SGF pH and followed by simulated intestinal fluid(SIF i.e.pH 7.4).FTIR spectra confirmed the formation of IPN beads.The release of CP was sustain at SGF pH(<20%)whereas in SIF media it was more(>75%).The kinetic model of IPN beads showed the release of CP was non-Fickian diffusion type.
基金Supported by Tianjin Science and Technology Planning Project(No.18PTSYJC00140)
文摘A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated. The addition of glutaraldehyde and α-tocopherol decreased the lightness and greenness and increased the yellowness of the chitosan-based film. Moreover, it also affected the compatibility of the film due to a decrease in the opacity values. The elongation at break(EB) and tensile strength(TS) values of the film decreased when the glutaraldehyde and α-tocopherol were added. In contrast, the Young’s modulus(YM) values increased. SEM micrographs showed coarse spots and pores on the surface and cross-section of the film when compared with the chitosan film. Based on the results, it was indicated that the chitosan structure was disconnected by the α-tocopherol, and the glutaraldehyde as a crosslinking agent generated a link between the chitosan network, which could be the cause of the reduced flexibility and the increased surface roughness of the film. However, the glutaraldehyde and α-tocopherol did not result in a significant difference in water vapour permeability(WVP) values. The glutaraldehyde influenced the release kinetics of the α-tocopherol as seen by the decrease of the diffusion coefficient values that were calculated using the Fickian diffusion model.
基金the National Natural Science Foundation of China(Grant No.81102401).
文摘Although therapeutic potential of neurotrophic factors(NTFs)has been well recognized for over two decades,attempts to translate that potential to the clinic have been disappointing,largely due to significant obstacles in delivery,including inadequate protein dose/kinetics released at target sites.Considerable efforts have been made to improve the therapeutic performance of NTFs.This articles reviews recent developments in localized delivery systems of NTFs for the neurological disorders treatments with a main focus on sustained delivery strategies.Different non-covalent binding approaches have been employed to immobilize proteins in hydrogels,microspheres,electrospun nanofibers,and their combined systems,which serve as depots for sustained local release of NTFs.The challenges associated with current NTFs delivery systems and how these systems can be applied to neurological diseases and disorders have been discussed in the review.In conclusion,optimal delivery systems for NTFs will be needed for reliable and meaningful clinical benefits;ideally,delivering a time and dose-controlled release of bioactive multiNTFs at different individual optimal kinetics to achieve multi-functions in target tissues is significant preferred.
文摘Biochar has been shown to be an effective organic soil amendment for the in-situ immobilization of lead(Pb).Little research has been done on the effects of biochar and zeolite interactions on Pb immobilization in contaminated calcareous soils.Therefore,the aim of this study was to investigate the effects of different levels of zeolite(2%and 4%,weight:weight)and biochars(3%,weight:weight)prepared from green compost(GB),poultry manure(PB),and municipal waste(MB)on the content of Pb in spinach shoots and Pb stabilization in a greenhouse experiment conducted using a Pb-contaminated calcareous soil.Application of GB and PB significantly decreased the Pb mobility factor(MF)from 2.8%to 4.6%and the cumulative Pb release(diethylenetriamine pentaacetate(DTPA)extraction)from 16.8%to 20.1%in the calcareous soil,which were further enhanced by the combined addition of zeolite,with Pb MF reduction from 4.4%to 8.4%and cumulative Pb release reduction from 24.8%to 28.6%.The enhancement of soil Pb immobilization was attributed to the properties of the amendments,such as high pH,ash content,and phosphorus content(10.5^(-1)1.0,390-435 g kg^(-1),and 2.5-4.3 g kg^(-1),respectively).Results of the soil Pb sequential extraction and Pb release kinetics were highly and significantly correlated with spinach shoot Pb content.Soil chemical data showed that the application of MB with 4%zeolite was the most effective treatment for immobilizing Pb(8.4%reduction in Pb MF and 28.6%reduction in cumulative DTPA-extractable Pb),which is in agreement with the results of the spinach shoot Pb(89.0%reduction in Pb uptake).
文摘<strong>Background: </strong>Recent decades witnessed a significant growth in terms of phytocompounds based therapeutics, extensively explored for almost all types of existing disorders. They have also been widely investigated in Neurodegenerative disorders (NDDs) and Chlorogenic acid (CGA), a polyphenolic compound having potential anti-inflammatory and anti-oxidative properties, emerged as a promising compound in ameliorating NDDs. Owing to its poor stability, bioavailability and release kinetics, CGA needed a suitable nanocarrier based pharmaceutical design for targeting NDDs. <strong>Objective: </strong>The current study is aimed at the <em>in-silico</em> validation of CGA as an effective therapeutic agent targeting various NDDs followed by the fabrication of polymeric nanoparticles-based carrier system to overcome its pharmacological limitations and improve its stability. <strong>Methods:</strong> A successful <em>in-silico</em> validation using molecular docking techniques along with synthesis of CGA loaded polymeric nanoparticles (CGA-NPs) by ionic gelation method was performed. The statistical optimisation of the developed CGA-NPs was done by Box Behnken method and then the optimized formulation of CGA-NPs was characterised using particle size analysis (PSA), Transmission electron microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR) along with in-vitro release kinetics analysis.<strong> Results & Conclusion:</strong> The results attained exhibited average particle size of 101.9 ± 1.5 nm, Polydispersibility (PDI) score of 0.065 and a ZP of <span style="white-space:nowrap;">−</span>17.4 mV. On a similar note, TEM results showed a size range of CGA-NPs between 90 - 110 nm with a spherical shape of NPs. Also, the data from in-vitro release kinetics showed a sustained release of CGA from the NPs following the first-order kinetics suggesting the appropriate designing of nanoformulation.
