[Objective] This study aimed to investigate the existing forms and bioaccessibility of vanadium(V) from soil and mineral of Panzhihua region.[Method] The representative Xigeda soil and vanadium-titanium magnetite we...[Objective] This study aimed to investigate the existing forms and bioaccessibility of vanadium(V) from soil and mineral of Panzhihua region.[Method] The representative Xigeda soil and vanadium-titanium magnetite were collected from Panzhihua region to determine the existing forms of vanadium from soil and mineral;in vitro bionic digestion model was established to measure the bioaccessibility of vanadium.[Result] The dissolved concentrations of vanadium from farmland,mining area and vanadium-titanium magnetite in gastric juice were respectively 5.02,9.50 and 3.88 mg/kg,and the bioaccessibility ranged from 0.09% to 3.00%;the dissolved concentrations of vanadium in intestinal juice were respectively 2.98,5.43 and 4.49 mg/kg,and the bioaccessibility ranged from 0.10% to 1.78%.The content of vanadium in various existing forms varied significantly,the contents of vanadium in non-specific adsorption state and specific adsorption state were low,but residual content was completely high,which accounted for 75.06%,95.32% and 86.27% of the total content of vanadium in samples.[Conclusion] Bioaccessibility of dissolved vanadium in gastric juice was higher than that in small intestinal juice.Vanadium from soil and mineral was difficult to generate morphological transformation and migration,which was the main reason for low bioaccessibility.展开更多
This study reports a case of unresectable intrahepatic mass-forming cholangiocarcinoma which showed a dramatic response to gemcitabine that led to curative resection and a long-term survival of more than five years.Si...This study reports a case of unresectable intrahepatic mass-forming cholangiocarcinoma which showed a dramatic response to gemcitabine that led to curative resection and a long-term survival of more than five years.Six and five cycles of gemcitabine monotherapy were administered separately over a three-year period and a radical excision was performed at 4.5 years after diagnosis.This case indicates the role of gemcitabine as a neoadjuvant chemotherapeutic agent for cholangiocarcinoma and guarantees a randomized controlled prospective study.展开更多
Based on the growth rates of population, Gross Domestic Products (GDP) and agriculture productivity, the areas of deforestation were predicted in Jutp ani village, Chitwan district, Nepal by Area Production Model (AP...Based on the growth rates of population, Gross Domestic Products (GDP) and agriculture productivity, the areas of deforestation were predicted in Jutp ani village, Chitwan district, Nepal by Area Production Model (APM). Through the APM simulation in this study, all of forestland will be transferred into agricu ltural land in 2030 at the rate of 24% per year on the current productivity. And if the productivity of subsistence food crop is assumed to increase at the rate of 1%, the productivity of market crop and export crop increase at the rate of 2% annually, deforestation rate will decrease to 17% per year, but only 124 hm2 forest land will be left till 2038. The agriculture productivity is a very impor tant factor for the deforestation, so intensification of agriculture management is more important.展开更多
This article based on the target products manufactured by the gasoline-type and aromatic-type continuous catalytic reforming (CCR) units makes an assessment on the technical indicators of these cata- lytic reforming u...This article based on the target products manufactured by the gasoline-type and aromatic-type continuous catalytic reforming (CCR) units makes an assessment on the technical indicators of these cata- lytic reforming units. This article also explores the technical measures for maximizing the target products delivered by the gasoline-type and aromatic-type CCR units with respect to the selection of catalysts, the optimization of feedstock and the optimized operating regime.展开更多
A non-invasive laser enhancing transdermal drug delivery technique has been investigated. The second harmonic wavelength of 532 nm of a Q-Switched Nd:YAG laser with pulse duration of 15 ns was used to irradiate on a b...A non-invasive laser enhancing transdermal drug delivery technique has been investigated. The second harmonic wavelength of 532 nm of a Q-Switched Nd:YAG laser with pulse duration of 15 ns was used to irradiate on a black polyethylene sheet covering on the surface of the drug solution, and hence produced pressure waves in the solution. Porcine skin and Rhodamine B were used as skin model and reagent respectively. Fluorescence microscope was employed to examine the mechanisms of drug delivery via the skin samples after laser treatment. The experiment revealed that the penetration depth of Rhodamine B under the illumination of laser increased with the energy density of the laser beam. After 20 laser shots at laser energy density of 70 mJ/cm2, the penetration depth reached 440 μm in 30 minutes, which was about three times as that without laser illumination. One possible explanation was that laser-induced pressure waves formed microchannels in the stratum corneum of the skin tissue. These microchannels provided much more effective paths for infiltration of Rhodamine B through the SC than follicular and intercellular paths. The drug solution diffused into the SC under the concentration gradient through the channels.展开更多
Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to sol...Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.展开更多
Striga hermonthica is a major constraint to smallholder sub-sistence agriculture production in the sub-Saharan African region. Low soil fertility and overall environmental degradation has contributed to the build-up o...Striga hermonthica is a major constraint to smallholder sub-sistence agriculture production in the sub-Saharan African region. Low soil fertility and overall environmental degradation has contributed to the build-up of the parasitic weed infestation. Improved cropping systems have to be introduced to address the interrelated problems of S. her-monthica and soil fertility decline. Thus, the effects of improved fallow with leguminous shrub Sesbania sesban on maize yields and levels of S. hermonthica infestation on farm land in the bimodal highlands of western Kenya were investigated. The experimental treatments were arranged in a phased entry, and randomized complete block scheme were six months Sesbania fallow, 18 months Sesbania fallow, six months natural fallow consisting of regrowth of natural vegetation without cultivation, 18 months natural fallow, continuous maize cropping without fertilizer application, and continuous maize cropping with P and N fertilization. Results show that Sesbania fallows significantly (p0.05) increase maize yield relative to continuous unfertilized maize. S. hermonthica plant populations decrease in continuous maize between the first season (mean = 428 000 ± 63 000 ha-1) and second season (mean=51 000 ± 15 000 ha-1), presumably in response to good weed management. S. hermonthica seed populations in the soil decrease throughout the duration of the experi-ment in the continuous maize treatments. Short-duration Sesbania fal-lows can provide modest yield improvements relative to continuous unfertilized maize, but short-duration weedy fallows are ineffective. Continuous maize cultivation with good weed control may provide more effective S. hermonthica control than fallowing.展开更多
Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthes...Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthesized paddle-wheel BODIPY-hexaoxatriphenylene(BODIPY is the abbreviation for BF_(2)-chelated dipyrromethenes)conjugates D-A complexes with the combination of both electronic structure calculations and nonadiabatic dynamics simulations.On the basis of computational results,we concluded that the BODIPY-hexaoxatriphenylene(BH)conjugates will be promoted to the local excited(LE)states of the BODIPY fragments upon excitation,which is followed by the ultrafast exciton transfer from LE state to charge transfer(CT).Instead of the photoinduced electron transfer process proposed in previous experimental work,such a exciton transfer process is accompanied with the photoinduced hole transfer from BODIPY to hexaoxatriphenylene.Additionally,solvent effects are found to play an important role in the photoinduced dynamics.Specifically,the hole transfer dynamics is accelerated by the acetonitrile solvent,which can be ascribed to significant influences of the solvents on the charge transfer states,i.e.the energy gaps between LE and CT excitons are reduced greatly and the non-adiabatic couplings are increased in the meantime.Our present work not only provides valuable insights into the underlying photoinduced mechanism of BH,but also can be helpful for the future design of novel donor-acceptor conjugates with better optoelectronic performance.展开更多
Nanoparticles drug delivery system has sustained and controlled release features as well as targeted drug delivery, which can change the characteristics of drug distribution in vivo. It can increase the stability of t...Nanoparticles drug delivery system has sustained and controlled release features as well as targeted drug delivery, which can change the characteristics of drug distribution in vivo. It can increase the stability of the drug and enhance drug bioavailability. The selective targeting of nanoparticles can be achieved through enhanced permeability and retention effect and a conjugated specific ligand or through the effects of physiological conditions, such as pH and temperature. Nanoparticles can be prepared by using a wide range of materials and can be used to encapsulate chemotherapeutic agents to reduce toxicity, which can be used for imaging, therapy, and diagnosis. In this research, recent progress on nanoparticles as a targeted drug delivery system will be reviewed, including positive-targeting, negative-targeting, and physicochemical-targeting used as anticancer drug carriers.展开更多
This document in order to solve the problem of the supply imbalance of the home nursing service, it is necessary to make use of the decisive role of the price mechanism in the optimal allocation of resources in view o...This document in order to solve the problem of the supply imbalance of the home nursing service, it is necessary to make use of the decisive role of the price mechanism in the optimal allocation of resources in view of the shortage of the supply of old-age service in China, the low quality and the low supply of effective supply. Based on the economic attributes of public goods and personal belongings, this paper divides the old-age service into the old-age service of private property and the properties of public goods (pure public goods and quasi-public goods) according to the family status, economic status and health status of the clients. This paper explores the theoretical basis of price decision mechanism and effective supply of these two kinds of old-age services, and finally puts forward the concrete measures of the reform of the old-age service price in the light of the actual situation of the current pension service in our country.展开更多
Introduction: Propofol is an intravenous general anesthetic and sedation drug for use in the induction and maintenance of anesthesia or sedation. It is included in WHO Model List of Essential medicines and approved b...Introduction: Propofol is an intravenous general anesthetic and sedation drug for use in the induction and maintenance of anesthesia or sedation. It is included in WHO Model List of Essential medicines and approved by the FDA (food and drug administration) in 1989. The side effects of Propofol have been studied widely in the last 25 years. They can be easily managed and that is why Propofol has become a fn'st choice drug for the most of the anesthesiologists worldwide. This paper presents a case report of Propofol induced pulmonary edema and also a review of some of the rarest and unusual manifestations of Propofol side effects. Some of them are urine discoloration, tissue necrosis, rhabdomyolysis and postoperative panereatitis. Methods and materials: A case summary of 18-years old woman with unusual postoperative pulmonary reaction was considered along with other documented cases. Several full-text articles were briefly analyzed for estimating the role of Propofol for a number of strange and potentially life threatening conditions. Results: Despite the low incidence rate, the presented case could be determined as a pulmonary edema due to its clinical features. Furthermore, rare drug reactions such as rhabdomyolysis, tissue necrosis, postoperative pancreatitis etc. may remain unrecognized and create diagnostic and therapeutic issues. Conclusions: Although the officially reported dangerous reaction, Propofol remains one of the best hypnotic and sedative agents. The better knowledge of the full list of drug reactions considered as rare and very rare is a guarantee of an adequate and a better therapeutic behavior.展开更多
One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is a...One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.展开更多
The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, th...The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, this issue is aggravated by the fact that, on one hand, rapid urbanization and greater levels and diversity of food consumption associated with the growing affluence of urban inhabitants has led to rising urban food demand, while on the other hand, the rapid loss of farmland due to urban expansion or irrational sprawl and increasing extreme weather events for agricultural producers due to the impact of global climate change is sharply reducing the urban food production and local supply capacity. Therefore how to realize the urban food supply potential and optimize the utilization of the urban farmlands to enhance the local food supply rate and improve urban food security more generally is becoming a key issue. In this paper, we use the case of Beijing to examine the opportunities to enhance the supply of local, affordably priced food under existing land resource constraints, by restructuring farmland utilization. In this paper, we firstly calculate the changes in the food footprint needed by Beijing and its food self-sufficiency rate over the thirty year period from 1981 to 2011. We show that although Beijing’s food footprint has grown from 11 800 to 29 400 km2 over this 30-year period, its food self- sufficiency rate has dropped from 59.3%, 35.8%, 37.3% and 13.1% to about 39.0%, 27.0%, 6.7% and 2.2% for vegetable, fruit, grain and edible oil, respectively. Following this analysis, we calculate Beijing’ s potential food production under different agricultural production allocation scenarios. We conclude that with a proper shift of farmland use, full utilization of temporary idle land, and the development of rooftop farming, Beijing could increase its vegetable self-sufficiency rate to 60% without significantly reducing the production of other types of local food. Given the sensitivity of fresh vegetables to long- distance transport, and the potential to reduce transport-related carbon emissions, this is a worthwhile adjustment that will benefit the city both by meeting the growing need of its residents for fresh food, and by improving the overall regional eco-environment.展开更多
Sorafenib is a novel antitumor drug,which is poorly absorbed in the gastrointestinal tract due to its low solubility in water.To improve the bioavailability of sorafenib,a self-microemulsifying drug delivery system(SM...Sorafenib is a novel antitumor drug,which is poorly absorbed in the gastrointestinal tract due to its low solubility in water.To improve the bioavailability of sorafenib,a self-microemulsifying drug delivery system(SMEDDS) formulation of sorafenib was prepared and its relative bioavailability in rats was evaluated.The blank SMEDDS was prepared from a mixture of ethyl oleate(oil phase,20%,w/w),Cremophol EL(surfactant,48%,w/w),PEG-400(co-surfactant,16%,w/w) and ethanol (co-surfactant,16%,w/w).Sorafenib was subsequently dissolved in the blank SMEDDS to obtain a sorafenib SMEDDS formulation with a final sorafenib concentration at 20 mg/mL.The particle size of the emulsified sorafenib SMEDDS was about 20-25 nm. Compared with sorafenib suspension,the prepared SMEDDS formulation exhibited no effect on the T_(max),but significantly increased the AUC,C_(max) and MRT and decreased the drug clearance.Most importantly,the oral bioavailability based on AUC_(0-72h) increased about 25 times after formulating sorafenib in SMEDDS.We concluded that SMEDDS could be a promising vesicle for the oral delivery of the poorly soluble antitumor drug sorafenib.展开更多
To enhance the oral absorption of the poorly water-soluble drug silybin, a self-microemulsifying drug delivery system (SMEDDS) composed of ethyl linoleate, Cremophor EL and PEG 400 for oral administration of silybin...To enhance the oral absorption of the poorly water-soluble drug silybin, a self-microemulsifying drug delivery system (SMEDDS) composed of ethyl linoleate, Cremophor EL and PEG 400 for oral administration of silybin was formulated, and its physicochemical properties and bioavailability of silybin were evaluated. The in vitro release of silybin from microemulsion and dispersion of silybin from SMEDDS were significantly faster than those from the commercial silybin hard capsule, respectively. The area under the drug concentration-time curve (AUC) and the mean maximum plasma level (Cmax) of the SMEDDS were remarkably greater than those of the hard capsule after oral administration to rats. The absorption of silybin formulated in SMEDDS exhibited a 2.3-fold increase in bioavailability as compared with the hard capsule. These results demonstrated that SMESDDS might be a useful drug delivery system for the oral delivery of the poorly water-soluble drug silybin.展开更多
Amphiphilic dendritic poly(glutarnic acid)-b-polyphenylalanine copolymers were synthesized using generation 3 dendritic poly(glutamic acid) as the macroinitiator in the ring-opening polymerization of NCA-Phe. The ...Amphiphilic dendritic poly(glutarnic acid)-b-polyphenylalanine copolymers were synthesized using generation 3 dendritic poly(glutamic acid) as the macroinitiator in the ring-opening polymerization of NCA-Phe. The block copolymers self-assembled micelles with polyphenylalanine segments as core and dendritic poly(glutamic acid) segments as shell. The biocompatibility of the micelles was studied. The release of the anticancer drug doxorubicin from the micelles was investigated in vitro. The results showed that the sustaining release of the drug could last for 60 h. The micellar drug release system was efficient in inhibiting the proliferation of HepG2 liver cancer cells, 75% cancer cells were killed under appropriate in vitro incubation.展开更多
Paclitaxel is a promising antineoplastic agent against a variety of human solid tumors, such as ovary, breast, lung, head and neck tumors, and melanoma. Owing to its poor solubility, the fast available formulation ofp...Paclitaxel is a promising antineoplastic agent against a variety of human solid tumors, such as ovary, breast, lung, head and neck tumors, and melanoma. Owing to its poor solubility, the fast available formulation ofpaclitaxel (Taxol) exists as a non-aqueous concentrate composed of Cremophor EL (polyethoxylated castor oil) and ethanol. It must be diluted to a suitable aqueous solution prior to long time intravenous infusion. Based on the components and usage, Taxol has serious adverse effects and is inconvenient for clinical use. To address these problems, the development of a less-toxic, better-tolerated, Cremophor EL-free formulation of paclitaxel has been attempted. In recent years, new drug delivery systems (DDS) including albumin-based nanoparticles, micelles, liposomes, etc. have been investigated. In this review, we present the formulations and delivery technologies of paclitaxel for injection and focus on some of preclinical and clinical experience on the formulations which are already on the market or under clinical stages. Finally, possible nanotechnology advantages, existing challenges and future perspectives of paclitaxel delivery are highlighted.展开更多
Recently, the power conversion efficiencies(PCEs) of all-polymer solar cells(all-PSCs) have increased rapidly. To further increase the PCE of all-PSCs, it is necessary to create new donor polymers matching the polymer...Recently, the power conversion efficiencies(PCEs) of all-polymer solar cells(all-PSCs) have increased rapidly. To further increase the PCE of all-PSCs, it is necessary to create new donor polymers matching the polymer acceptors. In this paper, we synthesize a new quinoxaline-based polymer donor PBQ8 with n-octyl side chain on the quinoxaline unit, which possesses the same skeleton structure to the previously reported PBQ5(with isooctyl side chain). The effects of alkyl side chains on the physicochemical properties of the polymer donor were investigated. In comparison with PBQ5, PBQ8 exhibits stronger intermolecular interactions and better molecular packing. When blending with polymer acceptor PY-IT, the PBQ8:PY-IT based devices demonstrated a higher PCE value of 17.04%, which is one of the highest PCEs occurred in the all-PSCs. And the PBQ5:PY-IT(PCE 15.56%, Voc0.907 V, FF 69.72%, and Jsc24.60 m A cm^(-2)) is much lower. The PBQ8:PY-IT blend displayed more efficient exciton dissociation, better molecular stacking properties, preferable phase separation and higher mobility. These indicate that as an effective method, side chain engineering can improve the efficiency of the all-PSCs.展开更多
基金Supported by National Natural Science Foundation of China(41101484)Discipline Innovation and Intelligence Plan for Colleges(B08037)International Cooperation Project of Ministry of Science and Technology(2011DFA101222)~~
文摘[Objective] This study aimed to investigate the existing forms and bioaccessibility of vanadium(V) from soil and mineral of Panzhihua region.[Method] The representative Xigeda soil and vanadium-titanium magnetite were collected from Panzhihua region to determine the existing forms of vanadium from soil and mineral;in vitro bionic digestion model was established to measure the bioaccessibility of vanadium.[Result] The dissolved concentrations of vanadium from farmland,mining area and vanadium-titanium magnetite in gastric juice were respectively 5.02,9.50 and 3.88 mg/kg,and the bioaccessibility ranged from 0.09% to 3.00%;the dissolved concentrations of vanadium in intestinal juice were respectively 2.98,5.43 and 4.49 mg/kg,and the bioaccessibility ranged from 0.10% to 1.78%.The content of vanadium in various existing forms varied significantly,the contents of vanadium in non-specific adsorption state and specific adsorption state were low,but residual content was completely high,which accounted for 75.06%,95.32% and 86.27% of the total content of vanadium in samples.[Conclusion] Bioaccessibility of dissolved vanadium in gastric juice was higher than that in small intestinal juice.Vanadium from soil and mineral was difficult to generate morphological transformation and migration,which was the main reason for low bioaccessibility.
文摘This study reports a case of unresectable intrahepatic mass-forming cholangiocarcinoma which showed a dramatic response to gemcitabine that led to curative resection and a long-term survival of more than five years.Six and five cycles of gemcitabine monotherapy were administered separately over a three-year period and a radical excision was performed at 4.5 years after diagnosis.This case indicates the role of gemcitabine as a neoadjuvant chemotherapeutic agent for cholangiocarcinoma and guarantees a randomized controlled prospective study.
文摘Based on the growth rates of population, Gross Domestic Products (GDP) and agriculture productivity, the areas of deforestation were predicted in Jutp ani village, Chitwan district, Nepal by Area Production Model (APM). Through the APM simulation in this study, all of forestland will be transferred into agricu ltural land in 2030 at the rate of 24% per year on the current productivity. And if the productivity of subsistence food crop is assumed to increase at the rate of 1%, the productivity of market crop and export crop increase at the rate of 2% annually, deforestation rate will decrease to 17% per year, but only 124 hm2 forest land will be left till 2038. The agriculture productivity is a very impor tant factor for the deforestation, so intensification of agriculture management is more important.
文摘This article based on the target products manufactured by the gasoline-type and aromatic-type continuous catalytic reforming (CCR) units makes an assessment on the technical indicators of these cata- lytic reforming units. This article also explores the technical measures for maximizing the target products delivered by the gasoline-type and aromatic-type CCR units with respect to the selection of catalysts, the optimization of feedstock and the optimized operating regime.
基金SRIT program in Beijing Institute of Technology,Grant number:P0000043
文摘A non-invasive laser enhancing transdermal drug delivery technique has been investigated. The second harmonic wavelength of 532 nm of a Q-Switched Nd:YAG laser with pulse duration of 15 ns was used to irradiate on a black polyethylene sheet covering on the surface of the drug solution, and hence produced pressure waves in the solution. Porcine skin and Rhodamine B were used as skin model and reagent respectively. Fluorescence microscope was employed to examine the mechanisms of drug delivery via the skin samples after laser treatment. The experiment revealed that the penetration depth of Rhodamine B under the illumination of laser increased with the energy density of the laser beam. After 20 laser shots at laser energy density of 70 mJ/cm2, the penetration depth reached 440 μm in 30 minutes, which was about three times as that without laser illumination. One possible explanation was that laser-induced pressure waves formed microchannels in the stratum corneum of the skin tissue. These microchannels provided much more effective paths for infiltration of Rhodamine B through the SC than follicular and intercellular paths. The drug solution diffused into the SC under the concentration gradient through the channels.
基金the Natural Science Key Foundation of Heilongjiang Province of China (No. ZJG0503) China-UK Sci-ence Network from Royal Society UK
文摘Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.
基金supported by Swedish International Development Cooperation Agency (Sida)
文摘Striga hermonthica is a major constraint to smallholder sub-sistence agriculture production in the sub-Saharan African region. Low soil fertility and overall environmental degradation has contributed to the build-up of the parasitic weed infestation. Improved cropping systems have to be introduced to address the interrelated problems of S. her-monthica and soil fertility decline. Thus, the effects of improved fallow with leguminous shrub Sesbania sesban on maize yields and levels of S. hermonthica infestation on farm land in the bimodal highlands of western Kenya were investigated. The experimental treatments were arranged in a phased entry, and randomized complete block scheme were six months Sesbania fallow, 18 months Sesbania fallow, six months natural fallow consisting of regrowth of natural vegetation without cultivation, 18 months natural fallow, continuous maize cropping without fertilizer application, and continuous maize cropping with P and N fertilization. Results show that Sesbania fallows significantly (p0.05) increase maize yield relative to continuous unfertilized maize. S. hermonthica plant populations decrease in continuous maize between the first season (mean = 428 000 ± 63 000 ha-1) and second season (mean=51 000 ± 15 000 ha-1), presumably in response to good weed management. S. hermonthica seed populations in the soil decrease throughout the duration of the experi-ment in the continuous maize treatments. Short-duration Sesbania fal-lows can provide modest yield improvements relative to continuous unfertilized maize, but short-duration weedy fallows are ineffective. Continuous maize cultivation with good weed control may provide more effective S. hermonthica control than fallowing.
基金supported by the National Natural Science Foundation of China(No.22003043 for Xiang-Yang Liu)the National Natural Science Foundation of China(No.21688102,No.21590801,and No.21520102005 for Ganglong Cui)+1 种基金Sichuan Science and Technology Program(No.2020YJ0161 for Xiang-Yang Liu)the High Performance Computing Center of Sichuan Normal University。
文摘Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthesized paddle-wheel BODIPY-hexaoxatriphenylene(BODIPY is the abbreviation for BF_(2)-chelated dipyrromethenes)conjugates D-A complexes with the combination of both electronic structure calculations and nonadiabatic dynamics simulations.On the basis of computational results,we concluded that the BODIPY-hexaoxatriphenylene(BH)conjugates will be promoted to the local excited(LE)states of the BODIPY fragments upon excitation,which is followed by the ultrafast exciton transfer from LE state to charge transfer(CT).Instead of the photoinduced electron transfer process proposed in previous experimental work,such a exciton transfer process is accompanied with the photoinduced hole transfer from BODIPY to hexaoxatriphenylene.Additionally,solvent effects are found to play an important role in the photoinduced dynamics.Specifically,the hole transfer dynamics is accelerated by the acetonitrile solvent,which can be ascribed to significant influences of the solvents on the charge transfer states,i.e.the energy gaps between LE and CT excitons are reduced greatly and the non-adiabatic couplings are increased in the meantime.Our present work not only provides valuable insights into the underlying photoinduced mechanism of BH,but also can be helpful for the future design of novel donor-acceptor conjugates with better optoelectronic performance.
基金Supported by a grant from the foundation of Guangzhou Municipal Key Project for Special Scientific Plan(No.2008A1-E4101)
文摘Nanoparticles drug delivery system has sustained and controlled release features as well as targeted drug delivery, which can change the characteristics of drug distribution in vivo. It can increase the stability of the drug and enhance drug bioavailability. The selective targeting of nanoparticles can be achieved through enhanced permeability and retention effect and a conjugated specific ligand or through the effects of physiological conditions, such as pH and temperature. Nanoparticles can be prepared by using a wide range of materials and can be used to encapsulate chemotherapeutic agents to reduce toxicity, which can be used for imaging, therapy, and diagnosis. In this research, recent progress on nanoparticles as a targeted drug delivery system will be reviewed, including positive-targeting, negative-targeting, and physicochemical-targeting used as anticancer drug carriers.
文摘This document in order to solve the problem of the supply imbalance of the home nursing service, it is necessary to make use of the decisive role of the price mechanism in the optimal allocation of resources in view of the shortage of the supply of old-age service in China, the low quality and the low supply of effective supply. Based on the economic attributes of public goods and personal belongings, this paper divides the old-age service into the old-age service of private property and the properties of public goods (pure public goods and quasi-public goods) according to the family status, economic status and health status of the clients. This paper explores the theoretical basis of price decision mechanism and effective supply of these two kinds of old-age services, and finally puts forward the concrete measures of the reform of the old-age service price in the light of the actual situation of the current pension service in our country.
文摘Introduction: Propofol is an intravenous general anesthetic and sedation drug for use in the induction and maintenance of anesthesia or sedation. It is included in WHO Model List of Essential medicines and approved by the FDA (food and drug administration) in 1989. The side effects of Propofol have been studied widely in the last 25 years. They can be easily managed and that is why Propofol has become a fn'st choice drug for the most of the anesthesiologists worldwide. This paper presents a case report of Propofol induced pulmonary edema and also a review of some of the rarest and unusual manifestations of Propofol side effects. Some of them are urine discoloration, tissue necrosis, rhabdomyolysis and postoperative panereatitis. Methods and materials: A case summary of 18-years old woman with unusual postoperative pulmonary reaction was considered along with other documented cases. Several full-text articles were briefly analyzed for estimating the role of Propofol for a number of strange and potentially life threatening conditions. Results: Despite the low incidence rate, the presented case could be determined as a pulmonary edema due to its clinical features. Furthermore, rare drug reactions such as rhabdomyolysis, tissue necrosis, postoperative pancreatitis etc. may remain unrecognized and create diagnostic and therapeutic issues. Conclusions: Although the officially reported dangerous reaction, Propofol remains one of the best hypnotic and sedative agents. The better knowledge of the full list of drug reactions considered as rare and very rare is a guarantee of an adequate and a better therapeutic behavior.
文摘One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.
基金funded by the National Natural Science Foundation of China (40971100)
文摘The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, this issue is aggravated by the fact that, on one hand, rapid urbanization and greater levels and diversity of food consumption associated with the growing affluence of urban inhabitants has led to rising urban food demand, while on the other hand, the rapid loss of farmland due to urban expansion or irrational sprawl and increasing extreme weather events for agricultural producers due to the impact of global climate change is sharply reducing the urban food production and local supply capacity. Therefore how to realize the urban food supply potential and optimize the utilization of the urban farmlands to enhance the local food supply rate and improve urban food security more generally is becoming a key issue. In this paper, we use the case of Beijing to examine the opportunities to enhance the supply of local, affordably priced food under existing land resource constraints, by restructuring farmland utilization. In this paper, we firstly calculate the changes in the food footprint needed by Beijing and its food self-sufficiency rate over the thirty year period from 1981 to 2011. We show that although Beijing’s food footprint has grown from 11 800 to 29 400 km2 over this 30-year period, its food self- sufficiency rate has dropped from 59.3%, 35.8%, 37.3% and 13.1% to about 39.0%, 27.0%, 6.7% and 2.2% for vegetable, fruit, grain and edible oil, respectively. Following this analysis, we calculate Beijing’ s potential food production under different agricultural production allocation scenarios. We conclude that with a proper shift of farmland use, full utilization of temporary idle land, and the development of rooftop farming, Beijing could increase its vegetable self-sufficiency rate to 60% without significantly reducing the production of other types of local food. Given the sensitivity of fresh vegetables to long- distance transport, and the potential to reduce transport-related carbon emissions, this is a worthwhile adjustment that will benefit the city both by meeting the growing need of its residents for fresh food, and by improving the overall regional eco-environment.
基金The 973 Project(Grant No.2009CB930300)Scientific and Technological Major Special Project -"Significant Creation of New Drugs"(Grant No.2009ZX09310-001).
文摘Sorafenib is a novel antitumor drug,which is poorly absorbed in the gastrointestinal tract due to its low solubility in water.To improve the bioavailability of sorafenib,a self-microemulsifying drug delivery system(SMEDDS) formulation of sorafenib was prepared and its relative bioavailability in rats was evaluated.The blank SMEDDS was prepared from a mixture of ethyl oleate(oil phase,20%,w/w),Cremophol EL(surfactant,48%,w/w),PEG-400(co-surfactant,16%,w/w) and ethanol (co-surfactant,16%,w/w).Sorafenib was subsequently dissolved in the blank SMEDDS to obtain a sorafenib SMEDDS formulation with a final sorafenib concentration at 20 mg/mL.The particle size of the emulsified sorafenib SMEDDS was about 20-25 nm. Compared with sorafenib suspension,the prepared SMEDDS formulation exhibited no effect on the T_(max),but significantly increased the AUC,C_(max) and MRT and decreased the drug clearance.Most importantly,the oral bioavailability based on AUC_(0-72h) increased about 25 times after formulating sorafenib in SMEDDS.We concluded that SMEDDS could be a promising vesicle for the oral delivery of the poorly soluble antitumor drug sorafenib.
文摘To enhance the oral absorption of the poorly water-soluble drug silybin, a self-microemulsifying drug delivery system (SMEDDS) composed of ethyl linoleate, Cremophor EL and PEG 400 for oral administration of silybin was formulated, and its physicochemical properties and bioavailability of silybin were evaluated. The in vitro release of silybin from microemulsion and dispersion of silybin from SMEDDS were significantly faster than those from the commercial silybin hard capsule, respectively. The area under the drug concentration-time curve (AUC) and the mean maximum plasma level (Cmax) of the SMEDDS were remarkably greater than those of the hard capsule after oral administration to rats. The absorption of silybin formulated in SMEDDS exhibited a 2.3-fold increase in bioavailability as compared with the hard capsule. These results demonstrated that SMESDDS might be a useful drug delivery system for the oral delivery of the poorly water-soluble drug silybin.
基金supported by the National Basic Research Program of China (973 Program,2011CB606206)National High-Tech Research & Development Program of China (863 Program,2007AA021801)+2 种基金National Natural Science Foundation of China (50633020 & 50830105)Sichuan Youth Science & Technology Foundation (07ZQ026-013)Open Fund of Engineering Research Center of Biomass Materials,Ministry of Education (2010LF4002)
文摘Amphiphilic dendritic poly(glutarnic acid)-b-polyphenylalanine copolymers were synthesized using generation 3 dendritic poly(glutamic acid) as the macroinitiator in the ring-opening polymerization of NCA-Phe. The block copolymers self-assembled micelles with polyphenylalanine segments as core and dendritic poly(glutamic acid) segments as shell. The biocompatibility of the micelles was studied. The release of the anticancer drug doxorubicin from the micelles was investigated in vitro. The results showed that the sustaining release of the drug could last for 60 h. The micellar drug release system was efficient in inhibiting the proliferation of HepG2 liver cancer cells, 75% cancer cells were killed under appropriate in vitro incubation.
基金Key Project from the Ministry of Science and Technology(Grant No.2014ZX09507001-010)Innovation Team of Ministry of Education(Grant No.BMU20110263)
文摘Paclitaxel is a promising antineoplastic agent against a variety of human solid tumors, such as ovary, breast, lung, head and neck tumors, and melanoma. Owing to its poor solubility, the fast available formulation ofpaclitaxel (Taxol) exists as a non-aqueous concentrate composed of Cremophor EL (polyethoxylated castor oil) and ethanol. It must be diluted to a suitable aqueous solution prior to long time intravenous infusion. Based on the components and usage, Taxol has serious adverse effects and is inconvenient for clinical use. To address these problems, the development of a less-toxic, better-tolerated, Cremophor EL-free formulation of paclitaxel has been attempted. In recent years, new drug delivery systems (DDS) including albumin-based nanoparticles, micelles, liposomes, etc. have been investigated. In this review, we present the formulations and delivery technologies of paclitaxel for injection and focus on some of preclinical and clinical experience on the formulations which are already on the market or under clinical stages. Finally, possible nanotechnology advantages, existing challenges and future perspectives of paclitaxel delivery are highlighted.
基金supported by the National Key Research and Development Program of China(2019YFA0705900)the National Natural Science Foundation of China(51820105003,21734008,61904181,and 52173188)+1 种基金the Key Research Program of the Chinese Academy of Sciences(XDPB13)the Basic and Applied Basic Research Major Program of Guangdong Province(2019B030302007)。
文摘Recently, the power conversion efficiencies(PCEs) of all-polymer solar cells(all-PSCs) have increased rapidly. To further increase the PCE of all-PSCs, it is necessary to create new donor polymers matching the polymer acceptors. In this paper, we synthesize a new quinoxaline-based polymer donor PBQ8 with n-octyl side chain on the quinoxaline unit, which possesses the same skeleton structure to the previously reported PBQ5(with isooctyl side chain). The effects of alkyl side chains on the physicochemical properties of the polymer donor were investigated. In comparison with PBQ5, PBQ8 exhibits stronger intermolecular interactions and better molecular packing. When blending with polymer acceptor PY-IT, the PBQ8:PY-IT based devices demonstrated a higher PCE value of 17.04%, which is one of the highest PCEs occurred in the all-PSCs. And the PBQ5:PY-IT(PCE 15.56%, Voc0.907 V, FF 69.72%, and Jsc24.60 m A cm^(-2)) is much lower. The PBQ8:PY-IT blend displayed more efficient exciton dissociation, better molecular stacking properties, preferable phase separation and higher mobility. These indicate that as an effective method, side chain engineering can improve the efficiency of the all-PSCs.