This paper studies the structure and properties of the polycarbonate polyurethane epoxy resin (PCPU EP) blends being resistant to hydrolysis.The samples were analyzed by an infrared spectrome...This paper studies the structure and properties of the polycarbonate polyurethane epoxy resin (PCPU EP) blends being resistant to hydrolysis.The samples were analyzed by an infrared spectrometer,a differential scanning calorimeter,a scanning electron microscope and a dynamic viscoelastometer.The results show that PCPU EP blends have excellent resistance to hydrolysis and mechanical properties at the ratio of PCPU to EP equal to 10/100 (wt/wt).展开更多
The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid a...The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60?) C for 1h and then was heated to (85?) C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions.展开更多
The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matt...The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matter accumulation, distribution of ions, the amount of polyamines (PAs) bound to tonoplast proteins as well as lipid composition and the activity of tonoplast vesicles isolated from roots were investigated. The results showed that soaking with Put or Spd could retard salt injury, promote GR and dry matter accumulation, and increase K+/Na+ in the roots. Compared with NaCl_treated plants, phospholipid content in root tonoplast rose by soaking with Put and Spd, while the level of galactose in lipids was decreased. Moreover, the ratio in noncovalently conjugated PA contents of (Spd+PAx (an unknown PA)) to (Put+Dap (diaminopropane)), and the total contents of covalently and noncovalently conjugated PAs were all increased. Statistical analysis indicated that the ratio of (Spd+PAx) to (Put+Dap) was significantly and positively correlated with the activities of membrane associated enzymes H+_ATPase and H+_PPase.展开更多
Aim The objectives of the present study were to prepare stealthy vincristine plus quinacrine liposomes and evaluate the pharmacokinetics in Sprague-Dawley rats. Methods Anti-resistant stealthy liposomes were prepared ...Aim The objectives of the present study were to prepare stealthy vincristine plus quinacrine liposomes and evaluate the pharmacokinetics in Sprague-Dawley rats. Methods Anti-resistant stealthy liposomes were prepared by incorporating vincristine with quinacrine together using the ammonium sulfate gradient loading procedure. For the pharmacokinetic study, Sprague-Dawley rats were divided into two groups: each rat in the Group Ⅰwas administered intravenously via tail vein as stealthy liposomal vincristine plus quinacrine, and the Group Ⅱ similarly given as a mixture solution of free vincristine plus free quinacrine. The concentrations of vincristine and quinacrine in plasma were measured by HPLC with diode array detection and fluorescence detection, respectively. Results The mean particle size of stealthy liposomes was 135.9 ±7.1 nm and the encapsulation efficiencies of stealthy liposomes were 〉 90% for vincristine, and 〉 85% for quinacrine, respectively. Administered as the stealthy vincristine plus quinacrine liposomes, the plasma exposures of both vincristine and quinacrine were significantly extended, and the mean concentrations of both vincristine and quinacrine were significantly higher compared to those given as the mixture solution of free vincristine plus free quinacrine. The Cmax, t1/2, AUC0-24 h values of vincristine for stealthy liposomal group were significantly increased, but the total clearance Cl values decreased, as compared to those of free drug group, respectively. Similarly, the Cmax, t1/2 and AUC0-24 h values of quinacrine for the stealthy liposomal group were significantly increased, but the total clearance C1 values decreased, as compared to those of free quinacrine. Conclusion The anti-resistant stealthy liposomes are successfully prepared by incorporating vincristine with quinacrine, and the liposomes extend significantly the duration in blood circulation and improve evidently the plasma concentrations of both vincristine and quinacrine.展开更多
Hepatic steatosis affects 20% to 30% of the general adult population in the western world. Currently, the technique of choice for determining hepatic fat deposition and the stage of fibrosis is liver biopsy. However, ...Hepatic steatosis affects 20% to 30% of the general adult population in the western world. Currently, the technique of choice for determining hepatic fat deposition and the stage of fibrosis is liver biopsy. However, it is an invasive procedure and its use is limited, particularly in children. It may also be subject to sampling error. Non-invasive techniques such as ultrasound, computerised tomography (CT), magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H MRS) can detect hepatic steatosis, but currently cannot distinguish between simple steatosis and steatohepatitis, or stage the degree of fibrosis accurately. Ultrasound is widely used to detect hepatic steatosis, but its sensitivity is reduced in the morbidly obese and also in those with small amounts of fatty infiltration. It has been used to grade hepatic fat content, but this is subjective. CT can detect hepatic steatosis, but exposes subjects to ionising radiation, thus limiting its use in longitudinal studies and in children. Recently, magnetic resonance (MR) techniques using chemical shift imaging have provided a quantitative assessment of the degree of hepatic fatty infiltration, which correlates well with liver biopsy results in the same patients. Similarly, in vivo 1H MRS is a fast, safe, non-invasive method forthe quantification of intrahepatocellular lipid (IHCL) levels. Both techniques will be useful tools in future longitudinal clinical studies, either in examining the natural history of conditions causing hepatic steatosis (e.g. non-alcoholic fatty liver disease), or in testing new treatments for these conditions.展开更多
The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance o...The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance of larval gilthead seabream to various stress factors such as exposure to air ( lack of dissolved oxygen), changes in water temperature (low) and salinity ( high) were determined. This study showed that microparticulate diet with natural fish oil and soybean lecithin was the most effective for increasing the tolerance of larval gilthead seabream to various stresses, and that microparticulate diet with natural fish oil and palmitic acid (16:0) was more effective than microparticulate diet with DHA oil and soybean lecithin.展开更多
The investigating of the hot press process parameters on the flexural properties of LVL (Laminated Veneer Lumber) reinforced composites derived from rubber wood veneer reinforced with fiber glass woven and epoxy adh...The investigating of the hot press process parameters on the flexural properties of LVL (Laminated Veneer Lumber) reinforced composites derived from rubber wood veneer reinforced with fiber glass woven and epoxy adhesive were performed via the DOE (design of experimental) approach. It was discovered that pressure was the most significantly and negatively effect on the product properties. Enhancing in the mechanical properties was related to decrease the processing pressure. Beside, press time was also significantly and positively effect. Although time was not clearly reflect from the mechanical results, but it was detected from the ANOVA (analysis of variance)results. The mechanical properties were increased with increasing compression time. From the results, the optimal condition to maximize mechanical properties was assumed at low pressure, 15 bars, low temperature, 70℃, and long time, 60 mins. The durability testing including screw nail withdrawal strength, water absorption, and termite resistance of LVL reinforced composite were also studied. The results are shown that the LVL wood has superior properties when compare with solid woods. It was found the withdrawal strength of LVL reinforce composite was higher than the solid woods. As expected that solid woods, except eucalyptus, had low water absorption resistance as it more hygroscopic corresponded to LVL reinforced wood. Also solid woods, except teal(, had low resistance to termite attack. Therefore, LVL reinforced was the best candidate by mean of durability properties compared to solid wood.展开更多
The dynamics of a bacterial population exposed to the minimum inhibitory concentration (MIC) of an antibiotic is an important issue in pharmacological research. Therefore, a novel antibiotic susceptibility test is u...The dynamics of a bacterial population exposed to the minimum inhibitory concentration (MIC) of an antibiotic is an important issue in pharmacological research. Therefore, a novel antibiotic susceptibility test is urgently needed that can both precisely determine the MIC and accurately select antibiotic-resistant strains from clinical bacterial populations. For this purpose, we developed a method based on Fick's laws of diffusion using agar plates containing a linear gradient of antibiotic. The gradient plate contained two layers. The bottom layer consisted of 15 mL agar containing the appropriate concentration of enrofloxacin and allowed to harden in the form of a wedge with the plate slanted such that the entire bottom was just covered. The upper layer consisted of 15 mL plain nutrient agar added with the plate held in the horizontal position. After allowing vertical diffusion of the drug from the bottom agar layer for 12 h, the enrofloxacin concentration was diluted in proportion to the ratio of the agar layer thicknesses. The uniform linear concentration gradient was verified by measuring the enrofloxacin concentration on the agar surface. When heavy bacterial suspensions were spread on the agar surface and incubated for more than 12 h, only resistant cells were able to form colonies beyond the boundary of confluent growth of susceptible cells. In this way, the true MIC of enrofloxacin was determined. The MICs obtained using this linear gradient plate were consistent with those obtained using conventional antibiotic susceptibility tests. Discrete colonies were then spread onto a gradient plate with higher antibiotic concentrations; the boundary line increased significantly, and gene mutations conferring resistance were identified. This new method enables the rapid identification of resistant strains in the bacterial population. Use of the linear gradient plate can easily identify the precise MIC and reveal the dynamic differentiation of bacteria near the MIC. This method allows the study of genetic and physiological characteristics of individual strains, and may be useful for early warning of antibiotic resistance that may occur after use of certain antirnicrobial agents, and guide clinical treatment.展开更多
Multidrug resistance (MDR) of breast cancer is a major cause of failure in chemotherapy. In the present study, a distearoylphosphatidyl ethanolamine-polyethylene glycol-pemetrexed (DSPE-PEG2000-PMT) conjugate was ...Multidrug resistance (MDR) of breast cancer is a major cause of failure in chemotherapy. In the present study, a distearoylphosphatidyl ethanolamine-polyethylene glycol-pemetrexed (DSPE-PEG2000-PMT) conjugate was synthesized from DSPE-PEG2000-NH2 and pemetrexed, and targeted sunitinib plus vinorelbine liposomes were developed by modifying DSPE-PEG20o0-PMT onto the surface of liposomes to overcome the MDR of breast cancer. The synthesized DSPE-PEG2000-PMT was confirmed to be consistent with the target product by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). The concentrations of sunitinib and vinorelbine were measured simultaneously by high performance liquid chromatography (HPLC). The analysis was performed on an ODS column at 30℃ at a wavelength of 215 nm with the mobile phase consisting of acetonitrile, 0.05 M KH2PO4 (pH 3.5) and triethylamine (35:65:0.3, v/v/v). The limits of detection for sunitinib and vinorelbine were 25 ng/mL and 5 ng/mL, respectively, and the limits of quantification for both drugs were 0.25μg/mL. Two drugs were linearly correlated in the range of 0.5-25.0 μg/mL. For varying types of liposomes, the encapsulation efficiencies were 〉90%; the particle sizes were approximately 90 nm, and zeta potentials were slightly negative. The inhibitory effects were evaluated in the resistant breast cancer MCF-7/Adr cells. The results revealed that targeted sunitinib plus vinorelbine liposomes exhibited the strongest inhibitory effect to the resistant MCF-7/Adr cells among the varying formulations. Targeted coumarin liposomes were used as a fluorescent probe to evaluate the targeting effect to resistant breast cancer MCF-7/Adr cells. The results demonstrated that the targeted coumarin liposomes displayed the highest cellular uptake compared to non-targeted formulations. In conclusion, the targeted sunitinib plus vinorelbine liposomes represented a novel type of nano-formulations, which could accumulate in the resistant breast cancer cells, thereby inhibiting proliferation of the resistant cancer cells. Accordingly, the targeted sunitinib plus vinorelbine liposomes may provide a new strategy for circumventing the drug resistance in the resistant breast cancer.展开更多
Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional ...Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional similarities in their natural history and ecology, and thus, these 2 species encounter similar abiotic stress (such as periodic starvation) in their natural habitat. Here, we measured the cold tolerance of the 2 species and examined whether recent feeding or food deprivation, as well as body composition (body mass and lipid content) and condition (quantified as mass-to-size residuals) affect their cold tolerance. In contrast to other insects, in which food deprivation either enhanced or impaired cold tolerance, prolonged fasting had no effect on the cold tolerance of either species, which had similar cold tolerance. The 2 species differed, however, in how cold tolerance related to body mass and lipid content: although body mass was positively correlated with the wormlion cold tolerance, lipid content was a more reliable predictor of cold tolerance in the antlions. Cold tolerance also underwent greater change with ontogeny in wormlions than in antlions. We discuss possible reasons for this lack of effect of food deprivation on both species' cold tolerance, such as their high starvation tolerance (being sit-and-wait predators).展开更多
In the present paper, Charpy impact resistance of aluminum-epoxy laminated composites in both crack divider and crack ar-rester configurations has been investigated. In both configurations, an analytical investigation...In the present paper, Charpy impact resistance of aluminum-epoxy laminated composites in both crack divider and crack ar-rester configurations has been investigated. In both configurations, an analytical investigation has been carried out to evaluate the effects of layers thickness on impact resistance of the specimens. A model based on fuzzy logic for predicting impact re-sistance of the specimens has been presented. For purpose of building the model, training and testing using experimental re-sults from 126 specimens produced from two basic composites were conducted. The data used for the input data in fuzzy logic models are arranged in a format of 7 input parameters that cover the thickness of layers, the number of layers, the adhesive type, the crack tip configuration, the content of SiC particles, the content of methacrylated butadiene-styrene particles and the number of test trial. According to these input parameters, in the fuzzy logic model, the impact resistance of each specimen was predicted. The training and testing results in the fuzzy logic model have shown a strong potential for predicting impact resis-tance of aluminum-epoxy laminated composites.展开更多
文摘This paper studies the structure and properties of the polycarbonate polyurethane epoxy resin (PCPU EP) blends being resistant to hydrolysis.The samples were analyzed by an infrared spectrometer,a differential scanning calorimeter,a scanning electron microscope and a dynamic viscoelastometer.The results show that PCPU EP blends have excellent resistance to hydrolysis and mechanical properties at the ratio of PCPU to EP equal to 10/100 (wt/wt).
文摘The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60?) C for 1h and then was heated to (85?) C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions.
文摘The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matter accumulation, distribution of ions, the amount of polyamines (PAs) bound to tonoplast proteins as well as lipid composition and the activity of tonoplast vesicles isolated from roots were investigated. The results showed that soaking with Put or Spd could retard salt injury, promote GR and dry matter accumulation, and increase K+/Na+ in the roots. Compared with NaCl_treated plants, phospholipid content in root tonoplast rose by soaking with Put and Spd, while the level of galactose in lipids was decreased. Moreover, the ratio in noncovalently conjugated PA contents of (Spd+PAx (an unknown PA)) to (Put+Dap (diaminopropane)), and the total contents of covalently and noncovalently conjugated PAs were all increased. Statistical analysis indicated that the ratio of (Spd+PAx) to (Put+Dap) was significantly and positively correlated with the activities of membrane associated enzymes H+_ATPase and H+_PPase.
基金National Natural Science Foundation of China(No.30572260).
文摘Aim The objectives of the present study were to prepare stealthy vincristine plus quinacrine liposomes and evaluate the pharmacokinetics in Sprague-Dawley rats. Methods Anti-resistant stealthy liposomes were prepared by incorporating vincristine with quinacrine together using the ammonium sulfate gradient loading procedure. For the pharmacokinetic study, Sprague-Dawley rats were divided into two groups: each rat in the Group Ⅰwas administered intravenously via tail vein as stealthy liposomal vincristine plus quinacrine, and the Group Ⅱ similarly given as a mixture solution of free vincristine plus free quinacrine. The concentrations of vincristine and quinacrine in plasma were measured by HPLC with diode array detection and fluorescence detection, respectively. Results The mean particle size of stealthy liposomes was 135.9 ±7.1 nm and the encapsulation efficiencies of stealthy liposomes were 〉 90% for vincristine, and 〉 85% for quinacrine, respectively. Administered as the stealthy vincristine plus quinacrine liposomes, the plasma exposures of both vincristine and quinacrine were significantly extended, and the mean concentrations of both vincristine and quinacrine were significantly higher compared to those given as the mixture solution of free vincristine plus free quinacrine. The Cmax, t1/2, AUC0-24 h values of vincristine for stealthy liposomal group were significantly increased, but the total clearance Cl values decreased, as compared to those of free drug group, respectively. Similarly, the Cmax, t1/2 and AUC0-24 h values of quinacrine for the stealthy liposomal group were significantly increased, but the total clearance C1 values decreased, as compared to those of free quinacrine. Conclusion The anti-resistant stealthy liposomes are successfully prepared by incorporating vincristine with quinacrine, and the liposomes extend significantly the duration in blood circulation and improve evidently the plasma concentrations of both vincristine and quinacrine.
基金Grants from the Novo Nordisk UK Research Foundation (supporting S.R.M)Pfizer Global Research and Development (Sandwich, UK)the British Medical Research Council and the United Kingdom Department of Health Research and Development Initiative
文摘Hepatic steatosis affects 20% to 30% of the general adult population in the western world. Currently, the technique of choice for determining hepatic fat deposition and the stage of fibrosis is liver biopsy. However, it is an invasive procedure and its use is limited, particularly in children. It may also be subject to sampling error. Non-invasive techniques such as ultrasound, computerised tomography (CT), magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H MRS) can detect hepatic steatosis, but currently cannot distinguish between simple steatosis and steatohepatitis, or stage the degree of fibrosis accurately. Ultrasound is widely used to detect hepatic steatosis, but its sensitivity is reduced in the morbidly obese and also in those with small amounts of fatty infiltration. It has been used to grade hepatic fat content, but this is subjective. CT can detect hepatic steatosis, but exposes subjects to ionising radiation, thus limiting its use in longitudinal studies and in children. Recently, magnetic resonance (MR) techniques using chemical shift imaging have provided a quantitative assessment of the degree of hepatic fatty infiltration, which correlates well with liver biopsy results in the same patients. Similarly, in vivo 1H MRS is a fast, safe, non-invasive method forthe quantification of intrahepatocellular lipid (IHCL) levels. Both techniques will be useful tools in future longitudinal clinical studies, either in examining the natural history of conditions causing hepatic steatosis (e.g. non-alcoholic fatty liver disease), or in testing new treatments for these conditions.
文摘The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance of larval gilthead seabream to various stress factors such as exposure to air ( lack of dissolved oxygen), changes in water temperature (low) and salinity ( high) were determined. This study showed that microparticulate diet with natural fish oil and soybean lecithin was the most effective for increasing the tolerance of larval gilthead seabream to various stresses, and that microparticulate diet with natural fish oil and palmitic acid (16:0) was more effective than microparticulate diet with DHA oil and soybean lecithin.
文摘The investigating of the hot press process parameters on the flexural properties of LVL (Laminated Veneer Lumber) reinforced composites derived from rubber wood veneer reinforced with fiber glass woven and epoxy adhesive were performed via the DOE (design of experimental) approach. It was discovered that pressure was the most significantly and negatively effect on the product properties. Enhancing in the mechanical properties was related to decrease the processing pressure. Beside, press time was also significantly and positively effect. Although time was not clearly reflect from the mechanical results, but it was detected from the ANOVA (analysis of variance)results. The mechanical properties were increased with increasing compression time. From the results, the optimal condition to maximize mechanical properties was assumed at low pressure, 15 bars, low temperature, 70℃, and long time, 60 mins. The durability testing including screw nail withdrawal strength, water absorption, and termite resistance of LVL reinforced composite were also studied. The results are shown that the LVL wood has superior properties when compare with solid woods. It was found the withdrawal strength of LVL reinforce composite was higher than the solid woods. As expected that solid woods, except eucalyptus, had low water absorption resistance as it more hygroscopic corresponded to LVL reinforced wood. Also solid woods, except teal(, had low resistance to termite attack. Therefore, LVL reinforced was the best candidate by mean of durability properties compared to solid wood.
基金supported by the National Natural Science Foundation of China (Grant No.81171621)Shandong Province Young and Middle-Aged Scientists Research Awards Fund (Grant No.2006BS02008)China Postdoctoral Science Foundation Funded Project (Grant No.20080440451)
文摘The dynamics of a bacterial population exposed to the minimum inhibitory concentration (MIC) of an antibiotic is an important issue in pharmacological research. Therefore, a novel antibiotic susceptibility test is urgently needed that can both precisely determine the MIC and accurately select antibiotic-resistant strains from clinical bacterial populations. For this purpose, we developed a method based on Fick's laws of diffusion using agar plates containing a linear gradient of antibiotic. The gradient plate contained two layers. The bottom layer consisted of 15 mL agar containing the appropriate concentration of enrofloxacin and allowed to harden in the form of a wedge with the plate slanted such that the entire bottom was just covered. The upper layer consisted of 15 mL plain nutrient agar added with the plate held in the horizontal position. After allowing vertical diffusion of the drug from the bottom agar layer for 12 h, the enrofloxacin concentration was diluted in proportion to the ratio of the agar layer thicknesses. The uniform linear concentration gradient was verified by measuring the enrofloxacin concentration on the agar surface. When heavy bacterial suspensions were spread on the agar surface and incubated for more than 12 h, only resistant cells were able to form colonies beyond the boundary of confluent growth of susceptible cells. In this way, the true MIC of enrofloxacin was determined. The MICs obtained using this linear gradient plate were consistent with those obtained using conventional antibiotic susceptibility tests. Discrete colonies were then spread onto a gradient plate with higher antibiotic concentrations; the boundary line increased significantly, and gene mutations conferring resistance were identified. This new method enables the rapid identification of resistant strains in the bacterial population. Use of the linear gradient plate can easily identify the precise MIC and reveal the dynamic differentiation of bacteria near the MIC. This method allows the study of genetic and physiological characteristics of individual strains, and may be useful for early warning of antibiotic resistance that may occur after use of certain antirnicrobial agents, and guide clinical treatment.
基金Beijing Natural Science Foundation(Grant No.7131009)the National Basic Research Program of China(Grant No.973 program,2013CB932501)+1 种基金the National Natural Science Foundation of China(Grant No.81373343)the Innovation Team of Ministry of Education(Grant No.BMU20110263)
文摘Multidrug resistance (MDR) of breast cancer is a major cause of failure in chemotherapy. In the present study, a distearoylphosphatidyl ethanolamine-polyethylene glycol-pemetrexed (DSPE-PEG2000-PMT) conjugate was synthesized from DSPE-PEG2000-NH2 and pemetrexed, and targeted sunitinib plus vinorelbine liposomes were developed by modifying DSPE-PEG20o0-PMT onto the surface of liposomes to overcome the MDR of breast cancer. The synthesized DSPE-PEG2000-PMT was confirmed to be consistent with the target product by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). The concentrations of sunitinib and vinorelbine were measured simultaneously by high performance liquid chromatography (HPLC). The analysis was performed on an ODS column at 30℃ at a wavelength of 215 nm with the mobile phase consisting of acetonitrile, 0.05 M KH2PO4 (pH 3.5) and triethylamine (35:65:0.3, v/v/v). The limits of detection for sunitinib and vinorelbine were 25 ng/mL and 5 ng/mL, respectively, and the limits of quantification for both drugs were 0.25μg/mL. Two drugs were linearly correlated in the range of 0.5-25.0 μg/mL. For varying types of liposomes, the encapsulation efficiencies were 〉90%; the particle sizes were approximately 90 nm, and zeta potentials were slightly negative. The inhibitory effects were evaluated in the resistant breast cancer MCF-7/Adr cells. The results revealed that targeted sunitinib plus vinorelbine liposomes exhibited the strongest inhibitory effect to the resistant MCF-7/Adr cells among the varying formulations. Targeted coumarin liposomes were used as a fluorescent probe to evaluate the targeting effect to resistant breast cancer MCF-7/Adr cells. The results demonstrated that the targeted coumarin liposomes displayed the highest cellular uptake compared to non-targeted formulations. In conclusion, the targeted sunitinib plus vinorelbine liposomes represented a novel type of nano-formulations, which could accumulate in the resistant breast cancer cells, thereby inhibiting proliferation of the resistant cancer cells. Accordingly, the targeted sunitinib plus vinorelbine liposomes may provide a new strategy for circumventing the drug resistance in the resistant breast cancer.
文摘Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional similarities in their natural history and ecology, and thus, these 2 species encounter similar abiotic stress (such as periodic starvation) in their natural habitat. Here, we measured the cold tolerance of the 2 species and examined whether recent feeding or food deprivation, as well as body composition (body mass and lipid content) and condition (quantified as mass-to-size residuals) affect their cold tolerance. In contrast to other insects, in which food deprivation either enhanced or impaired cold tolerance, prolonged fasting had no effect on the cold tolerance of either species, which had similar cold tolerance. The 2 species differed, however, in how cold tolerance related to body mass and lipid content: although body mass was positively correlated with the wormlion cold tolerance, lipid content was a more reliable predictor of cold tolerance in the antlions. Cold tolerance also underwent greater change with ontogeny in wormlions than in antlions. We discuss possible reasons for this lack of effect of food deprivation on both species' cold tolerance, such as their high starvation tolerance (being sit-and-wait predators).
文摘In the present paper, Charpy impact resistance of aluminum-epoxy laminated composites in both crack divider and crack ar-rester configurations has been investigated. In both configurations, an analytical investigation has been carried out to evaluate the effects of layers thickness on impact resistance of the specimens. A model based on fuzzy logic for predicting impact re-sistance of the specimens has been presented. For purpose of building the model, training and testing using experimental re-sults from 126 specimens produced from two basic composites were conducted. The data used for the input data in fuzzy logic models are arranged in a format of 7 input parameters that cover the thickness of layers, the number of layers, the adhesive type, the crack tip configuration, the content of SiC particles, the content of methacrylated butadiene-styrene particles and the number of test trial. According to these input parameters, in the fuzzy logic model, the impact resistance of each specimen was predicted. The training and testing results in the fuzzy logic model have shown a strong potential for predicting impact resis-tance of aluminum-epoxy laminated composites.