Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silic...Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.展开更多
TiO2/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam （EB） irradiation-pretreated graphene as the raw materials. The prod...TiO2/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam （EB） irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation dose were investigated. It was found that the preparation conditions had a significant effect on the structure and properties of the final products. The irradiated graphene was covered with petal-like anatase TiO2 nanoparticles, which were more uniform and smaller in size than those in products synthesized without EB irradiation-pretreated graphene. The photocatalytic activities of the products were evaluated using the photocatalytic degradation of methyl orange as a probe reaction. The results showed that the products synthesized using EB irradiation-pretreated graphene exhibited higher photocatalytic activities than those using graphene without EB irradiation pretreatment.展开更多
AIM: To investigate the effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with cirrhosis induced by carbon tetrachloride were randomly divided into two groups,...AIM: To investigate the effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with cirrhosis induced by carbon tetrachloride were randomly divided into two groups, one n =13 receiving 0.5mg.kg(-1) per day of N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, for 10 days, whereas the other group (n =13) and control (n =10) rats were administrated the same volume of 9g.L(-1) saline. Half gastric emptying time and 2h residual rate were measured by SPECT, using (99m)Tc-DTPA-labeled barium sulfate as test meal. Gastrointestinal transition time was recorded simultaneously. Serum concentration of nitric oxide (NO) was determined by the kinetic cadmium reduction and colorimetric methods. Immunohistochemical SABC method was used to observe the expression and distribution of three types of nitric oxide synthase (NOS) isoforms in the rat gastrointestinal tract. Western blot was used to detect expression of gastrointestinal NOS isoforms. RESULTS: Half gastric emptying time and trans-gastrointestinal time were significantly prolonged(124.0 +/- 26.4 min; 33.7 +/- 8.9 min; 72.1 +/- 15.3 min; P【0.01), (12.4 +/- 0.5h; 9.5 +/- 0.3h; 8.2 +/- 0.8h; P【0.01), 2h residual rate was raised in cirrhotic rats than in controls and cirrhotic rats treated with L-NAME (54.9 +/- 7.6%,13.7 +/- 3.2%, 34.9 +/- 10.3%, P【0.01). Serum concentration of NO was significantly increased in cirrhotic rats than in the other groups (8.20 +/- 2.48) micromol.L(-1), (5.94 +/-1.07) micromol.L(-1) and control (5.66 +/- 1.60 micromol.L(-1), P【0.01. NOS staining intensities which were mainly located in the gastrointestinal tissues were markedly lower in cirrhotic rats than in the controls and cirrhotic rats after treated with L-NAME. CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L-NAME. Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats.展开更多
Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 120...Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 1200 mg/L could be totally biodegraded by A. radioresistens USTB-04 as the sole carbon source less than 4 d in the presence of phosphate and urea as phosphorus and nitrogen sources, respectively. Biodegradation of MP was also achieved using cell-free extract of A. radioresistens USTB-04. MP at an initial concentration of 130 mg/L was completely biodegraded in 2 h in the presence of cell-free extract with a protein concentration of 148.0 mg/L, which was increased with the increase of pH from 5.0 to 8.0. Contrary to published reports, no intermediate or final degradation metabolites of MP could be observed. Thus we suggest that the cleavage of C-C bond on the benzene ring other than P-O bond may be the biodegradation pathway of MP by A. radioresistens USTB-04.展开更多
AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines ...AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines (TNF-alpha, IL-1 beta, and IFN-gamma) and bacterial lipopolysaccharide (LPS) mixture (CM) in the cultured rat hepatocytes, and examine their mechanisms action. METHODS: Rat hepatocytes were incubated with AG, L-NAME, L-NNA, Actinomycin D (ActD) and dexamethasone in a medium containing CM (LPS plus TNF-alpha, IL-1 beta, and IFN-gamma) for 24h. NO production in the cultured supernatant was measured with the Griess reaction. Intracellular cGMP level was detected with radioimmunoassy. RESULTS: NO production was markedly blocked by AG and L-NAME in a dose-dependent manner under inflammatory stimuli condition triggered by CM in vitro. The rate of the maximum inhibitory effects of L-NAME (38.9%) was less potent than that obtained with AG(53.7%, P 【 0.05). There was no significant difference between the inhibitory effects of AG and two L-arginine analogues on intracellular cGMP accumulation in rat cultured hepatocytes. Non-specific NOS expression inhibitor dexamethasone (DEX)and iNOS mRNA transcriptional inhibitor ActD also significantly inhibited CM-induced NO production. AG(0.1 mmol x L(-1)) and ActD (0.2 ng x L(-1)) were equipotent in decreasing NO production induced by inflammatory stimuli in vitro, and both effects were more potent than that induced by non-selectivity NOS activity inhibitor L-NAME (0.1 mmol x L(-1)) under similar stimuli conditions (P【0.01). CONCLUSION: AG is a potent selective inhibitor of inducible isoform of NOS,and the mechanism of action may be not only competitive inhibition in the substrate level, but also the gene expression level in rat hepatocytes.展开更多
Background Preeclampsia （PE） is a multifactorial pregnancy complication.Maternal underlying condition and adverse factors both influence the pathogenesis of PE.Abnormal lipid metabolism as a maternal underlying dise...Background Preeclampsia （PE） is a multifactorial pregnancy complication.Maternal underlying condition and adverse factors both influence the pathogenesis of PE.Abnormal lipid metabolism as a maternal underlying disease may participate in the occurrence and development of PE.This study aimed to observe the effects of adverse factors on PE-like symptoms of pregnant mice with genetic abnormal lipid metabolism.Methods Apolipoprotein C-Ⅲ （ApoC3） transgenic mice with abnormal lipid metabolism were subcutaneously injected with L-arginine methyl ester （L-NAME） or normal saline （NS） daily starting at Day 7 or 16 of pregnancy （ApoC3＋L-NA and ApoC3＋NS groups）,and wild-type （WT） mice served as a control （WT＋L-NA and WT＋NS groups）.All mice were subdivided into early and late subgroups by injection time.The mean arterial pressure （MAP） and urinary protein were measured.Pregnancy outcomes,including fetal weight,placental weight,live birth rate,and fetal absorption rate,were analyzed.Pathologic changes in the placenta were observed by hematoxylin-eosin staining.One-way analysis of variance,t-test,and x2 test were used for statistical analysis.Results MAP significantly increased for ApoC3＋NS groups compared with WT＋NS groups （P 〈0.05）,without significant difference in urine protein.Following L-NAME injection,MAP and urinary protein significantly increased for ApoC3＋L-NA and WT＋L-NA compared with the corresponding NS groups （P 〈0.05）,and the increase for ApoC3＋L-NA was more obvious.Urinary protein levels in early ApoC3＋L-NA and WT＋L-NA significantly increased compared with the corresponding late groups （P 〈0.05）.Fetal absorption rate significantly increased and fetal and placental weights significantly decreased in early ApoC3＋L-NA and WT＋L-NA compared with the corresponding NS groups （P 〈0.05）,without significant difference in late ApoC3＋L-NA and WT＋L-NA groups.Fetal weight in early ApoC3＋L-NA was significantly lower than in early WT＋L-NA 展开更多
Zhaohui peaches(Prunus persica Batsch)were treated with 0(CK), 1, 10 or 100 μmol L-1 methyl jasmonate(MeJA)vapor at 20℃ for 24 h before stored at 0℃ for 35 d. The untreated fruits showed chilling injury(CD symptoms...Zhaohui peaches(Prunus persica Batsch)were treated with 0(CK), 1, 10 or 100 μmol L-1 methyl jasmonate(MeJA)vapor at 20℃ for 24 h before stored at 0℃ for 35 d. The untreated fruits showed chilling injury(CD symptoms after 4 wk of storage, as indicated by increased fruit firmness and reduced ex-tractable juice, which is referred as leatheriness. Treatment with 1 and 10 μmol L-1 MeJA promoted normal ripening and softening, maintained higher levels of extractable juice, titratable acidity, pectinesterase(PE)and polygalacturonase(PC)activities, inhibited increases in fruit fresh weight loss, decay incidence, electrolyte leakage and MDA content, and improved color development, thereby preventing chilling injury symptoms development and maintaining edible quality. MeJA treatment also delayed the climacteric rise in respiratory rate, but promoted ethylene production during the later period of cold storage, suggesting that ethylene may involve in CI development of peaches. These results indicate that 1 and 10 μmol L-1 MeJA treatments could be used to reduce CI development and decay incidence in peaches.展开更多
The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramib...The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.展开更多
Objective: One appealing strategy to overcome and prevent resistant problem is the use of combined two or more antibacterial substances. Lawsone methyl ether(LME) is the naphthoquinone found in the leaves of Impatiens...Objective: One appealing strategy to overcome and prevent resistant problem is the use of combined two or more antibacterial substances. Lawsone methyl ether(LME) is the naphthoquinone found in the leaves of Impatiens balsamina. The objective of this study is to determine the interaction of LME with some antibiotics(ampicillin, tetracycline, norfloxacin, and clotrimazole) and a natural compound, artocarpin against methicillin-resistant Staphylococcus aureus(MRSA), Candida albicans, and Trychophyton rubrum.Methods: A broth microdilution method was used to determine the minimum inhibition concentration(MIC). Synergistic effects were evaluated at their own MIC using the checkerboard method and time-kill assay.Results: LME showed moderate antibacterial activity against MRSA with MIC value of 15.6 μg/mL, and exhibited strong antifungal activities against T. rubrum and C. albicans with MIC values of 7.8 and 3.9 μg/m L,respectively. The interaction of LME with the natural compound artocarpin against MRSA produced a synergy with fractional inhibitory concentration index(FICI) value of 0.31, while the combination of LME and clotrimazole exhibited synergy against C. albicans and T. rubrum with FICI values of 0.38 and 0.24, respectively. The time-kill assays confirmed that the compounds in combination enhanced their antimicrobial activities against the resistant microorganisms with different degrees.Conclusion: LME in combination with clotrimazole exhibited synergy effect against C. albicans and T.rubrum. In combination with artocarpin, it showed synergy effect against MRSA.展开更多
The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factor...The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factors influencing adsorption capacity of the composite such as pH, concentration of the dye, temperature, contact time, adsorbent dosage, ionic strength and surfactant were systematically investigated. The equilibrium data fitted very well to the Langmuir isotherm and the maximum adsorption capacity reached 1194 mg/g at 30℃. The thermodynamic parameters including △G0, △H0 and △S0 for the adsorption processes of MV on the composite were also calculated, and the negative △H0 and △G0 confirmed that the adsorption process was exothermicand spontaneous. The kinetic studies showed that the adsorption process was consistent with the pseudo second-order kinetic model and the desorption studies revealed that the regeneration of the composite adsorbent can be easily achieved.展开更多
In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice,the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis,bulliform tissue and bristle. The ...In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice,the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis,bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%,respectively,more than the common green leaf rice cultivar Chijiaoru-anzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days,the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH· free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo,qP and φPSⅡ decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH· scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is sug-gested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.展开更多
Two new 2-（quinonylcarboxamino）benzoates, named aconicarmiquinamides A （1） and B （2）, were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Their structures were determined by spec...Two new 2-（quinonylcarboxamino）benzoates, named aconicarmiquinamides A （1） and B （2）, were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic methyl 3.6- bis（ diethylamino ）benzoqunonylcarboxylate （3）.展开更多
A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution, Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. U...A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution, Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. Under the optimized conditions, an improved yield of 37.9 mol% was achieved.展开更多
The equilibrium and kinetics of methyl isobutyl ketone(MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity,initial total concentrations ...The equilibrium and kinetics of methyl isobutyl ketone(MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity,initial total concentrations of zirconium and hafnium and temperature.The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm,and the Freundlich isotherm constants(KF) are 3.53 and 0.64 mg/g,respectively.The equilibrium data of zirconium also fit the Langmuir adsorption isotherm,and the saturation adsorption capacity(Qmax) and the Langmuir isotherm constant(KL)are 75.93 mg/g and-0.012 7 L/g,respectively.The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model,and the rate constants of pseudo-second-order equation(k2) are-0.019 and 0.41 g/(mg·min),respectively.Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.展开更多
The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (I...The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.展开更多
A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high phot...A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high photocatalytic performance in Methyl Orange(MO)degradation under visible light.The best sample presented a degradation rate of 0.164 min^-1,which is 3.2 and 82 times as high as that of Bi4O5I2 and g-C3N4,respectively.The g-C3N4/Bi4O5I2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS)and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C3N4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C3N4 and Bi4O5I2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C3N4/Bi4O5I2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi4O5I2.Additionally,g-C3N4/Bi4O5I2 also presented high stability.·O2^- and holes were verified to be the main reactive species.展开更多
MgCoAl-hydrotalcite-like compounds （MgCoAI-HTLcs） were synthesized using the coprecipitation method of variable pH values. The effect of each factor on the preparation of HTLcs was discussed systematically, which in...MgCoAl-hydrotalcite-like compounds （MgCoAI-HTLcs） were synthesized using the coprecipitation method of variable pH values. The effect of each factor on the preparation of HTLcs was discussed systematically, which included pH values, mole ratios of Mg2＋ to Co2＋, the concentrations of the solution, and the temperature and time of the hydrothermal treatment. Besides, the thermal decomposition of MgCoAI-HTLcs was discussed. X-ray diffraction, thermogravimetric analysis, and FT-IR spectroscopy were performed to characterize the MgCoAI-HTLcs samples. The results showed that when the pH = 7.6-8.5 or 5.5-6.2, atomic ratios of （Mg^2＋＋Co2＋）/Al^3＋ 2 and Mg^2＋/Co^2＋ ranging from 1.00 to 2.00, temperature and time of hydrothermal treatment being 110℃ and 6 h, unique MgCoAI-HTLcs with high crystallinity could be obtained. When the calcination temperature was up to 250℃, the MgO phase was detected coexisting with Al2O3 and MgAl2O4 was highly spreaded on the derived mixed oxides. The synthesis reaction of benzoin methyl ether with methanol and benzaldehyde was chosen to study the catalytic activity of MgCoAI-HTLcs. The catalyst showed high activity and high stability in the synthesis of benzoin methyl ether in the feasible condition.展开更多
文摘Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.
基金The work was co-supported by the National Natural Science Foundation of China （No. 20871081）, the Science and Technology Commission of Shanghai Municipality （Nos. 10QH1401000 and 10DZ0500100）, the Research Funding of the State Key Laboratory of Chemical Engineering （ECUST）, the Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry （ECNU）, and Shanghai Leading Academic Disciplines （No. $30109）.
文摘TiO2/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam （EB） irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation dose were investigated. It was found that the preparation conditions had a significant effect on the structure and properties of the final products. The irradiated graphene was covered with petal-like anatase TiO2 nanoparticles, which were more uniform and smaller in size than those in products synthesized without EB irradiation-pretreated graphene. The photocatalytic activities of the products were evaluated using the photocatalytic degradation of methyl orange as a probe reaction. The results showed that the products synthesized using EB irradiation-pretreated graphene exhibited higher photocatalytic activities than those using graphene without EB irradiation pretreatment.
基金National Natural Science Foundation of China,No.39970901
文摘AIM: To investigate the effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with cirrhosis induced by carbon tetrachloride were randomly divided into two groups, one n =13 receiving 0.5mg.kg(-1) per day of N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, for 10 days, whereas the other group (n =13) and control (n =10) rats were administrated the same volume of 9g.L(-1) saline. Half gastric emptying time and 2h residual rate were measured by SPECT, using (99m)Tc-DTPA-labeled barium sulfate as test meal. Gastrointestinal transition time was recorded simultaneously. Serum concentration of nitric oxide (NO) was determined by the kinetic cadmium reduction and colorimetric methods. Immunohistochemical SABC method was used to observe the expression and distribution of three types of nitric oxide synthase (NOS) isoforms in the rat gastrointestinal tract. Western blot was used to detect expression of gastrointestinal NOS isoforms. RESULTS: Half gastric emptying time and trans-gastrointestinal time were significantly prolonged(124.0 +/- 26.4 min; 33.7 +/- 8.9 min; 72.1 +/- 15.3 min; P【0.01), (12.4 +/- 0.5h; 9.5 +/- 0.3h; 8.2 +/- 0.8h; P【0.01), 2h residual rate was raised in cirrhotic rats than in controls and cirrhotic rats treated with L-NAME (54.9 +/- 7.6%,13.7 +/- 3.2%, 34.9 +/- 10.3%, P【0.01). Serum concentration of NO was significantly increased in cirrhotic rats than in the other groups (8.20 +/- 2.48) micromol.L(-1), (5.94 +/-1.07) micromol.L(-1) and control (5.66 +/- 1.60 micromol.L(-1), P【0.01. NOS staining intensities which were mainly located in the gastrointestinal tissues were markedly lower in cirrhotic rats than in the controls and cirrhotic rats after treated with L-NAME. CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L-NAME. Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats.
基金Project supported by the National Natural Science Foundation of China (No.20377047,20507002)Innovation Foundation in University of Science and Technology Beijing.
文摘Biodegradation of methyl parathion （MP）, a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 1200 mg/L could be totally biodegraded by A. radioresistens USTB-04 as the sole carbon source less than 4 d in the presence of phosphate and urea as phosphorus and nitrogen sources, respectively. Biodegradation of MP was also achieved using cell-free extract of A. radioresistens USTB-04. MP at an initial concentration of 130 mg/L was completely biodegraded in 2 h in the presence of cell-free extract with a protein concentration of 148.0 mg/L, which was increased with the increase of pH from 5.0 to 8.0. Contrary to published reports, no intermediate or final degradation metabolites of MP could be observed. Thus we suggest that the cleavage of C-C bond on the benzene ring other than P-O bond may be the biodegradation pathway of MP by A. radioresistens USTB-04.
基金Project supported by the National Natural Science Foundation of China,No.39770861.and JANSSEN Science Research Foundation.
文摘AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines (TNF-alpha, IL-1 beta, and IFN-gamma) and bacterial lipopolysaccharide (LPS) mixture (CM) in the cultured rat hepatocytes, and examine their mechanisms action. METHODS: Rat hepatocytes were incubated with AG, L-NAME, L-NNA, Actinomycin D (ActD) and dexamethasone in a medium containing CM (LPS plus TNF-alpha, IL-1 beta, and IFN-gamma) for 24h. NO production in the cultured supernatant was measured with the Griess reaction. Intracellular cGMP level was detected with radioimmunoassy. RESULTS: NO production was markedly blocked by AG and L-NAME in a dose-dependent manner under inflammatory stimuli condition triggered by CM in vitro. The rate of the maximum inhibitory effects of L-NAME (38.9%) was less potent than that obtained with AG(53.7%, P 【 0.05). There was no significant difference between the inhibitory effects of AG and two L-arginine analogues on intracellular cGMP accumulation in rat cultured hepatocytes. Non-specific NOS expression inhibitor dexamethasone (DEX)and iNOS mRNA transcriptional inhibitor ActD also significantly inhibited CM-induced NO production. AG(0.1 mmol x L(-1)) and ActD (0.2 ng x L(-1)) were equipotent in decreasing NO production induced by inflammatory stimuli in vitro, and both effects were more potent than that induced by non-selectivity NOS activity inhibitor L-NAME (0.1 mmol x L(-1)) under similar stimuli conditions (P【0.01). CONCLUSION: AG is a potent selective inhibitor of inducible isoform of NOS,and the mechanism of action may be not only competitive inhibition in the substrate level, but also the gene expression level in rat hepatocytes.
基金his work was supported by a grant from the National Natural Science Foundation of China （No. 81370723） and the Specialized Research Fund for the Doctoral Program of Higher Education from the Ministry of Education of China （No. 20130001110111）.
文摘Background Preeclampsia （PE） is a multifactorial pregnancy complication.Maternal underlying condition and adverse factors both influence the pathogenesis of PE.Abnormal lipid metabolism as a maternal underlying disease may participate in the occurrence and development of PE.This study aimed to observe the effects of adverse factors on PE-like symptoms of pregnant mice with genetic abnormal lipid metabolism.Methods Apolipoprotein C-Ⅲ （ApoC3） transgenic mice with abnormal lipid metabolism were subcutaneously injected with L-arginine methyl ester （L-NAME） or normal saline （NS） daily starting at Day 7 or 16 of pregnancy （ApoC3＋L-NA and ApoC3＋NS groups）,and wild-type （WT） mice served as a control （WT＋L-NA and WT＋NS groups）.All mice were subdivided into early and late subgroups by injection time.The mean arterial pressure （MAP） and urinary protein were measured.Pregnancy outcomes,including fetal weight,placental weight,live birth rate,and fetal absorption rate,were analyzed.Pathologic changes in the placenta were observed by hematoxylin-eosin staining.One-way analysis of variance,t-test,and x2 test were used for statistical analysis.Results MAP significantly increased for ApoC3＋NS groups compared with WT＋NS groups （P 〈0.05）,without significant difference in urine protein.Following L-NAME injection,MAP and urinary protein significantly increased for ApoC3＋L-NA and WT＋L-NA compared with the corresponding NS groups （P 〈0.05）,and the increase for ApoC3＋L-NA was more obvious.Urinary protein levels in early ApoC3＋L-NA and WT＋L-NA significantly increased compared with the corresponding late groups （P 〈0.05）.Fetal absorption rate significantly increased and fetal and placental weights significantly decreased in early ApoC3＋L-NA and WT＋L-NA compared with the corresponding NS groups （P 〈0.05）,without significant difference in late ApoC3＋L-NA and WT＋L-NA groups.Fetal weight in early ApoC3＋L-NA was significantly lower than in early WT＋L-NA
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Education Ministry of China(2002-247)the Natural Science Foundation of Jiangsu Province,China(BK2001206).
文摘Zhaohui peaches(Prunus persica Batsch)were treated with 0(CK), 1, 10 or 100 μmol L-1 methyl jasmonate(MeJA)vapor at 20℃ for 24 h before stored at 0℃ for 35 d. The untreated fruits showed chilling injury(CD symptoms after 4 wk of storage, as indicated by increased fruit firmness and reduced ex-tractable juice, which is referred as leatheriness. Treatment with 1 and 10 μmol L-1 MeJA promoted normal ripening and softening, maintained higher levels of extractable juice, titratable acidity, pectinesterase(PE)and polygalacturonase(PC)activities, inhibited increases in fruit fresh weight loss, decay incidence, electrolyte leakage and MDA content, and improved color development, thereby preventing chilling injury symptoms development and maintaining edible quality. MeJA treatment also delayed the climacteric rise in respiratory rate, but promoted ethylene production during the later period of cold storage, suggesting that ethylene may involve in CI development of peaches. These results indicate that 1 and 10 μmol L-1 MeJA treatments could be used to reduce CI development and decay incidence in peaches.
基金This research is supported by National Natural Science Foundation of China (No.30170764)
文摘The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.
基金supported by The Thailand Research Fund (Grant No. DBG6180031)
文摘Objective: One appealing strategy to overcome and prevent resistant problem is the use of combined two or more antibacterial substances. Lawsone methyl ether(LME) is the naphthoquinone found in the leaves of Impatiens balsamina. The objective of this study is to determine the interaction of LME with some antibiotics(ampicillin, tetracycline, norfloxacin, and clotrimazole) and a natural compound, artocarpin against methicillin-resistant Staphylococcus aureus(MRSA), Candida albicans, and Trychophyton rubrum.Methods: A broth microdilution method was used to determine the minimum inhibition concentration(MIC). Synergistic effects were evaluated at their own MIC using the checkerboard method and time-kill assay.Results: LME showed moderate antibacterial activity against MRSA with MIC value of 15.6 μg/mL, and exhibited strong antifungal activities against T. rubrum and C. albicans with MIC values of 7.8 and 3.9 μg/m L,respectively. The interaction of LME with the natural compound artocarpin against MRSA produced a synergy with fractional inhibitory concentration index(FICI) value of 0.31, while the combination of LME and clotrimazole exhibited synergy against C. albicans and T. rubrum with FICI values of 0.38 and 0.24, respectively. The time-kill assays confirmed that the compounds in combination enhanced their antimicrobial activities against the resistant microorganisms with different degrees.Conclusion: LME in combination with clotrimazole exhibited synergy effect against C. albicans and T.rubrum. In combination with artocarpin, it showed synergy effect against MRSA.
基金supported by the Western Action Project of Chinese Academy of Science (No.KGCX2-YW-501)the Taihu Project of Jiangsu Provincial Science and Technology Office (No.BS2007118,BE2008087)the Key Laboratory of Resources and Environment Chemistry of West China,Hexi University(No.XZ0606)
文摘The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factors influencing adsorption capacity of the composite such as pH, concentration of the dye, temperature, contact time, adsorbent dosage, ionic strength and surfactant were systematically investigated. The equilibrium data fitted very well to the Langmuir isotherm and the maximum adsorption capacity reached 1194 mg/g at 30℃. The thermodynamic parameters including △G0, △H0 and △S0 for the adsorption processes of MV on the composite were also calculated, and the negative △H0 and △G0 confirmed that the adsorption process was exothermicand spontaneous. The kinetic studies showed that the adsorption process was consistent with the pseudo second-order kinetic model and the desorption studies revealed that the regeneration of the composite adsorbent can be easily achieved.
基金supported by the National Natural Science Foundation of China(Grant No.30270125)Guangdong Natural Science Foundation(Grant No.04002309)Project of CAS Knowledge Innovation Program(Grant No.KSCX2-SW-130).
文摘In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice,the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis,bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%,respectively,more than the common green leaf rice cultivar Chijiaoru-anzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days,the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH· free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo,qP and φPSⅡ decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH· scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is sug-gested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.
基金Financial support from the National Natural Science Foundation of China (Nos.21132009 and 30825044)the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT1007)the National Science and Technology Project of China (Nos.2012ZX09301002-002 and 2011ZX0 9307-002-01)
文摘Two new 2-（quinonylcarboxamino）benzoates, named aconicarmiquinamides A （1） and B （2）, were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic methyl 3.6- bis（ diethylamino ）benzoqunonylcarboxylate （3）.
文摘A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution, Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. Under the optimized conditions, an improved yield of 37.9 mol% was achieved.
文摘The equilibrium and kinetics of methyl isobutyl ketone(MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity,initial total concentrations of zirconium and hafnium and temperature.The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm,and the Freundlich isotherm constants(KF) are 3.53 and 0.64 mg/g,respectively.The equilibrium data of zirconium also fit the Langmuir adsorption isotherm,and the saturation adsorption capacity(Qmax) and the Langmuir isotherm constant(KL)are 75.93 mg/g and-0.012 7 L/g,respectively.The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model,and the rate constants of pseudo-second-order equation(k2) are-0.019 and 0.41 g/(mg·min),respectively.Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.
文摘The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.
基金financially supported by National Undergraduate Training Program for Innovation and Entrepreneurship(Nos.201810345012 and 201810345051)
文摘A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high photocatalytic performance in Methyl Orange(MO)degradation under visible light.The best sample presented a degradation rate of 0.164 min^-1,which is 3.2 and 82 times as high as that of Bi4O5I2 and g-C3N4,respectively.The g-C3N4/Bi4O5I2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS)and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C3N4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C3N4 and Bi4O5I2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C3N4/Bi4O5I2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi4O5I2.Additionally,g-C3N4/Bi4O5I2 also presented high stability.·O2^- and holes were verified to be the main reactive species.
基金Supported by the Natural Science Foundation of Shanxi Province(20001015).
文摘MgCoAl-hydrotalcite-like compounds （MgCoAI-HTLcs） were synthesized using the coprecipitation method of variable pH values. The effect of each factor on the preparation of HTLcs was discussed systematically, which included pH values, mole ratios of Mg2＋ to Co2＋, the concentrations of the solution, and the temperature and time of the hydrothermal treatment. Besides, the thermal decomposition of MgCoAI-HTLcs was discussed. X-ray diffraction, thermogravimetric analysis, and FT-IR spectroscopy were performed to characterize the MgCoAI-HTLcs samples. The results showed that when the pH = 7.6-8.5 or 5.5-6.2, atomic ratios of （Mg^2＋＋Co2＋）/Al^3＋ 2 and Mg^2＋/Co^2＋ ranging from 1.00 to 2.00, temperature and time of hydrothermal treatment being 110℃ and 6 h, unique MgCoAI-HTLcs with high crystallinity could be obtained. When the calcination temperature was up to 250℃, the MgO phase was detected coexisting with Al2O3 and MgAl2O4 was highly spreaded on the derived mixed oxides. The synthesis reaction of benzoin methyl ether with methanol and benzaldehyde was chosen to study the catalytic activity of MgCoAI-HTLcs. The catalyst showed high activity and high stability in the synthesis of benzoin methyl ether in the feasible condition.
