Heteropoly acid H_3PW_(12)O_(40)(PW) has been used as an effective catalyst for the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one derivatives.The present methodology offers several advantages,such as high yields,short...Heteropoly acid H_3PW_(12)O_(40)(PW) has been used as an effective catalyst for the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one derivatives.The present methodology offers several advantages,such as high yields,short reaction times,mild reaction condition and a recyclable catalyst with a very easy work up.展开更多
In a pH=0.65―1.5 NaAc-HCl medium, methylene blue(MB) reacts with 12-tungstophosphoric acid (TPA) by virtue of electrostatic attraction and hydrophobic force to form a 3:2 ion-association complex. As a result, the int...In a pH=0.65―1.5 NaAc-HCl medium, methylene blue(MB) reacts with 12-tungstophosphoric acid (TPA) by virtue of electrostatic attraction and hydrophobic force to form a 3:2 ion-association complex. As a result, the intensities of resonance Rayleigh scattering(RRS), second-order scattering(SOS) and frequency doubling scatte- ring(FDS) are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity(△I) are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits(3s) for MB are 2.3 ng/mL(RRS method), 5.6 ng/mL(SOS method) and 6.4 ng/mL(FDS method), respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5%―105.0%. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.展开更多
The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open rea...The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.展开更多
Δ12 fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds.By RT-PCR method,the full-length cDNAs of Δ12 fatty acid desaturase gene were isolated from p...Δ12 fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds.By RT-PCR method,the full-length cDNAs of Δ12 fatty acid desaturase gene were isolated from peanut(Arachis hypogaea L.) genotypes with normal and high ratio of oleic to linoleic acid,which were designated AhFAD2B and AhFAD2B',respectively.Sequence alignment of their coding regions revealed that an extra A was inserted at the position +442 bp of AhFAD2B' sequence of high oleic acid genotypes,which resulted in the shift of open reading frame and a truncated protein AhFAD2B',with the loss of one histidine box involved in metal ion complex required for the reduction of oxygen.Analysis of transcript level showed that the expression of Δ12 fatty acid desaturase gene in high oleic acid genotype was slightly lower than that in normal genotype.The enzyme activity experiment of yeast(Saccharomyces cerevisiae) cell transformed with AhFAD2B or AhFAD2B' proved that only AhFAD2B gene product showed significant Δ12 fatty acid desaturase activity,but AhFAD2B' gene product did not.These results suggested that the change of AhFAD2B' gene sequence resulted in lower activity or deactivation of Δ12 fatty acid desaturase in high oleic acid genotype.展开更多
The freshwater microalga Haematococcus pluvialis accumulates large amounts of fatty acids in response to adverse conditions.However,the key fatty acid desaturase genes in H.pluvialis remain unknown.In this study,we cl...The freshwater microalga Haematococcus pluvialis accumulates large amounts of fatty acids in response to adverse conditions.However,the key fatty acid desaturase genes in H.pluvialis remain unknown.In this study,we cloned and functionally characterized aΔ12 fatty acid desaturase gene,and designated it as HpFAD2.The open reading frame of HpFAD2 consisted of 1137 base pairs and encoded 378 amino acids.The deduced polypeptide showed 70%identity to other endoplasmic reticulumΔ12 fatty acid desaturases,whereas it had only 44%identity to plastidΔ12 fatty acid desaturases.The PSORT algorithm and phylogenetic analysis further confirmed its affiliation to the endoplasmic reticulumΔ12 fatty acid desaturases.Heterologous expression was performed in Saccharomyces cerevisiae cells transformed with the recombinant plasmid pYES2-HpFAD2.Two additional fatty acids(C16:2 and C18:2)were detected in the yeast transformants.The results indicatedΔ12 desaturation activity and substrate preference for C18:1 over C16:1.The transcriptional levels of H.pluvialis HpFAD2 at different growth stages were measured by quantitative polymerase chain reaction(PCR),indicating that the HpFAD2 transcriptional levels were significantly higher in red cells than those in green cells.Our study brings more insight into the fatty acid biosynthetic pathway of H.pluvialis.展开更多
In order to solve the serious leaching problem of supported heteropoly acid catalysts in polar reaction media,12-molybdophosphoric acid encapsulated in the supercage of Cs+-exchanged Y zeolite was prepared by the &quo...In order to solve the serious leaching problem of supported heteropoly acid catalysts in polar reaction media,12-molybdophosphoric acid encapsulated in the supercage of Cs+-exchanged Y zeolite was prepared by the "ship in the bottle" synthesis.The influence of ion-exchange conditions and the synthesis parameters on the encapsulation of PMo12 were investigated.The obtained solid sample was characterized by X-ray diffraction(XRD),31P magic angle spin nuclear magnetic resonance(MAS NMR) and Fourier Transform Infrared Spectroscopy(FT-IR),and its catalytic activity in the esterification of acetic acid and n-butanol was tested.The ion-exchange time,concentration of aqueous Cs+ solution,pH value,and amount of Mo added in the synthesis mixture were revealed to influence the encapsulation very remarkably.Under the optimal conditions,12-molybdophosphoric acid could be successfully encapsulated in the supercage of CsY zeolite,and the samples showed considerable catalytic activity and excellent reusability in the esterification reaction.展开更多
Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a ...Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).展开更多
Aluminum has been associated with neurodegenerative diseases.ALA(α-linolenic acid),an essential dietary component for human health,possesses prominent biological activities.Herein,we aim to explore the neuroprotectiv...Aluminum has been associated with neurodegenerative diseases.ALA(α-linolenic acid),an essential dietary component for human health,possesses prominent biological activities.Herein,we aim to explore the neuroprotective effects of ALA on aluminum toxicity and reveal the underlying mechanism.Results show that aluminum chloride(denoted as Al)enabled cell viability decline and apoptosis with oxidative stress and mitochondrial damage in differentiated rat pheochromocytoma cells(PC12)for 24 h incubation.Compared with Al(10 mmol/L)treatment alone,ALA(50μmol/L)pretreatment for 24 h significantly enhanced cell viability by 28.40%,and hindered cell apoptosis by 12.35%,together with recovering redox state balance and alleviating mitochondrial damage.It was measured that ALA treatment upregulated Bcl-2 expression and down-regulated Bax level,accompanied with an expression decline of caspase-3 and caspase-9.Meanwhile,ALA pretreatment was proved to increase protein kinase A(PKA)expression and to promote phosphorylation of cAMP response element-binding protein(p-CREB),resulting in elevation on the level of brain-derived neurotrophic factor(BDNF).The above results showed that ALA attenuated Al toxicity in PC12 cells by mediating the PKA-CREBBDNF signaling pathway.展开更多
A reversed phase high performance liquid chromatography (HPLC) method was established for the simultaneous determination of 12,13-dihydroxyeuparin and glycyrrhizic acid in Yanyanfang mixture.A Grace Apollo C 18 column...A reversed phase high performance liquid chromatography (HPLC) method was established for the simultaneous determination of 12,13-dihydroxyeuparin and glycyrrhizic acid in Yanyanfang mixture.A Grace Apollo C 18 column (250 mm 4.6 mm,5 mm) was used as the stationary phase and the mobile phase was composed of acetonitrile and aqueous phosphoric acid (0.2%,v/v).Gradient elution was carried out at the flow rate of 1.0 mL/min and the column temperature was 30 1C.An ultraviolet (UV) detector was used with a selected wavelength of 240 nm.Calibration curves were linear within the concentration range of 4.6-45.75 mg/mL for 12,13-dihydroxyeuparin (r40.9999) and 106.9-1068.9 mg/mL for glycyrrhizic acid (r40.9999),respectively.Recoveries were 102.18% for 12,13-dihydroxyeuparin and 101.17% for glycyrrhizic acid.The method developed could be applied to the simultaneous determination of 12,13dihydroxyeuparin and glycyrrhizic acid in Yanyanfang mixture.展开更多
Context: Metformin is frequently prescribed for the treatment of type 2 diabetes mellitus. It is recommended as a first line agent by the American Diabetes Association. Vitamin B12 deficiency has been suggested as a s...Context: Metformin is frequently prescribed for the treatment of type 2 diabetes mellitus. It is recommended as a first line agent by the American Diabetes Association. Vitamin B12 deficiency has been suggested as a side effect of metformin therapy;however, previous studies have not assessed the utility of methylmalonic acid levels as an indicator of vitamin B12 status. Objective: To investigate the prevalence of vitamin B12 deficiency in patients on metformin therapy for diabetes by utilizing both vitamin B12 and methylmalonic acid levels. Design, Setting, and Patients: Eighty-eight patients with diabetes, who were either on or off metformin therapy for at least thirty days, were enrolled in a case-controlled study. Blood work and questionnaires were used for analysis. Main Outcome Measures Study: Aims were to detect a clinically significant difference in the prevalence of vitamin B12 deficiency between metformin users and non-users, where such deficiency is defined by both low vitamin B12 and elevated methylmalonic acid levels. Results: Two Sample Equal Variance T-Tests were used to compare averages of measured values and the Chisquare test was used to determine the significance of calculated vitamin B12 deficiency rates between the two groups of patients. Two separate methods for defining vitamin B12 deficiency were utilized. There was no difference in the prevalence of vitamin B12 deficiency in metformin users compared with non-users by either method. Average homocysteine levels were higher in those not on metformin therapy. Conclusion: Vitamin B12 deficiency as defined by an elevated methylmalonic acid level was no greater in patients with diabetes on metformin therapy versus those patients not on metformin treatment.展开更多
A novel environmental friendly catalyst, H4SiW12O40/PAn was prepared and identified by FT-IR, XRD and TG/DTA. The optimal synthetic protocol was a PAn to H4SiW12O40 mass ratio of 1∶1, a 20 mL of methanol and a reacti...A novel environmental friendly catalyst, H4SiW12O40/PAn was prepared and identified by FT-IR, XRD and TG/DTA. The optimal synthetic protocol was a PAn to H4SiW12O40 mass ratio of 1∶1, a 20 mL of methanol and a reaction time of 2 h at reflux. It was used in catalytic synthesis of ten important ketals and acetals with a high catalytic activity. With an aldehyde/ketone to glycol molar ratio of 1∶1.5 and a 1 wt% catalyst loading, the yields of ketals and acetals could reach 60.0%-93.8 % after 1 h.展开更多
文摘Heteropoly acid H_3PW_(12)O_(40)(PW) has been used as an effective catalyst for the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one derivatives.The present methodology offers several advantages,such as high yields,short reaction times,mild reaction condition and a recyclable catalyst with a very easy work up.
基金Supported by the National Natural Science Foundation of China(No.20875078)the Fund of Chongqing Municipal Key Laboratory on Luminescence and Real-Time Analysis China(No.2006CA8006)
文摘In a pH=0.65―1.5 NaAc-HCl medium, methylene blue(MB) reacts with 12-tungstophosphoric acid (TPA) by virtue of electrostatic attraction and hydrophobic force to form a 3:2 ion-association complex. As a result, the intensities of resonance Rayleigh scattering(RRS), second-order scattering(SOS) and frequency doubling scatte- ring(FDS) are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity(△I) are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits(3s) for MB are 2.3 ng/mL(RRS method), 5.6 ng/mL(SOS method) and 6.4 ng/mL(FDS method), respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5%―105.0%. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.
基金The Basic Scientific Fund for National Public Research Institutes of China under contract No.2017Q09the Aoshan Science and Technology Innovation Project of Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2016ASKJ02+3 种基金the National Natural Science Foundation of China-Shandong Joint Funded Project under contract No.U1606404the National Natural Science Foundation of China under contract Nos 41776176 and 41806201the 973 Project from Chinese Ministry of Science and Technology under contract No.2015CB755904the Shandong Provincial Natural Science Foundation under contract No.ZR2015PD003
文摘The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.
文摘Δ12 fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds.By RT-PCR method,the full-length cDNAs of Δ12 fatty acid desaturase gene were isolated from peanut(Arachis hypogaea L.) genotypes with normal and high ratio of oleic to linoleic acid,which were designated AhFAD2B and AhFAD2B',respectively.Sequence alignment of their coding regions revealed that an extra A was inserted at the position +442 bp of AhFAD2B' sequence of high oleic acid genotypes,which resulted in the shift of open reading frame and a truncated protein AhFAD2B',with the loss of one histidine box involved in metal ion complex required for the reduction of oxygen.Analysis of transcript level showed that the expression of Δ12 fatty acid desaturase gene in high oleic acid genotype was slightly lower than that in normal genotype.The enzyme activity experiment of yeast(Saccharomyces cerevisiae) cell transformed with AhFAD2B or AhFAD2B' proved that only AhFAD2B gene product showed significant Δ12 fatty acid desaturase activity,but AhFAD2B' gene product did not.These results suggested that the change of AhFAD2B' gene sequence resulted in lower activity or deactivation of Δ12 fatty acid desaturase in high oleic acid genotype.
基金This study was supported by the Zhejiang Provincial Natural Science Foundation of China(No.LQ16D060001)the National Natural Science Foundation of China(No.41606163)+3 种基金the Natural Science Foundation of the Ningbo Government(No.2017A610288)the Ningbo Science and Technology Research Projects,China(No.2019B10006)the Zhejiang Major Science Project,China(No.2019C02057)the Earmarked Fund for Modern Agro-Industry Technology Research System,China(No.CARS-49)and partly sponsored by K.C.Wong Magna Fund at Ningbo University.
文摘The freshwater microalga Haematococcus pluvialis accumulates large amounts of fatty acids in response to adverse conditions.However,the key fatty acid desaturase genes in H.pluvialis remain unknown.In this study,we cloned and functionally characterized aΔ12 fatty acid desaturase gene,and designated it as HpFAD2.The open reading frame of HpFAD2 consisted of 1137 base pairs and encoded 378 amino acids.The deduced polypeptide showed 70%identity to other endoplasmic reticulumΔ12 fatty acid desaturases,whereas it had only 44%identity to plastidΔ12 fatty acid desaturases.The PSORT algorithm and phylogenetic analysis further confirmed its affiliation to the endoplasmic reticulumΔ12 fatty acid desaturases.Heterologous expression was performed in Saccharomyces cerevisiae cells transformed with the recombinant plasmid pYES2-HpFAD2.Two additional fatty acids(C16:2 and C18:2)were detected in the yeast transformants.The results indicatedΔ12 desaturation activity and substrate preference for C18:1 over C16:1.The transcriptional levels of H.pluvialis HpFAD2 at different growth stages were measured by quantitative polymerase chain reaction(PCR),indicating that the HpFAD2 transcriptional levels were significantly higher in red cells than those in green cells.Our study brings more insight into the fatty acid biosynthetic pathway of H.pluvialis.
基金Supported by the National Natural Science Foundation of China （20476046） and the ＂Qinglan＂ Project of Jiangsu Province for Young Researchers.
文摘In order to solve the serious leaching problem of supported heteropoly acid catalysts in polar reaction media,12-molybdophosphoric acid encapsulated in the supercage of Cs+-exchanged Y zeolite was prepared by the "ship in the bottle" synthesis.The influence of ion-exchange conditions and the synthesis parameters on the encapsulation of PMo12 were investigated.The obtained solid sample was characterized by X-ray diffraction(XRD),31P magic angle spin nuclear magnetic resonance(MAS NMR) and Fourier Transform Infrared Spectroscopy(FT-IR),and its catalytic activity in the esterification of acetic acid and n-butanol was tested.The ion-exchange time,concentration of aqueous Cs+ solution,pH value,and amount of Mo added in the synthesis mixture were revealed to influence the encapsulation very remarkably.Under the optimal conditions,12-molybdophosphoric acid could be successfully encapsulated in the supercage of CsY zeolite,and the samples showed considerable catalytic activity and excellent reusability in the esterification reaction.
基金Supported by the National Natural Science Foundation of China(21476065)the China National Tobacco Corporation
文摘Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).
基金supported by the National Natural Science Foundation of China (31972041, 32101955)the China Agriculture Research System of MOF and MARA (CARS-12)+1 种基金the Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences (CAASASTIP-2016-OCRI)the Key Scientific Research Projects of Hubei Province (2020BCA086)
文摘Aluminum has been associated with neurodegenerative diseases.ALA(α-linolenic acid),an essential dietary component for human health,possesses prominent biological activities.Herein,we aim to explore the neuroprotective effects of ALA on aluminum toxicity and reveal the underlying mechanism.Results show that aluminum chloride(denoted as Al)enabled cell viability decline and apoptosis with oxidative stress and mitochondrial damage in differentiated rat pheochromocytoma cells(PC12)for 24 h incubation.Compared with Al(10 mmol/L)treatment alone,ALA(50μmol/L)pretreatment for 24 h significantly enhanced cell viability by 28.40%,and hindered cell apoptosis by 12.35%,together with recovering redox state balance and alleviating mitochondrial damage.It was measured that ALA treatment upregulated Bcl-2 expression and down-regulated Bax level,accompanied with an expression decline of caspase-3 and caspase-9.Meanwhile,ALA pretreatment was proved to increase protein kinase A(PKA)expression and to promote phosphorylation of cAMP response element-binding protein(p-CREB),resulting in elevation on the level of brain-derived neurotrophic factor(BDNF).The above results showed that ALA attenuated Al toxicity in PC12 cells by mediating the PKA-CREBBDNF signaling pathway.
基金supported by Guangdong Natural Product Reference Material Research & Development Central Lab,the First Affiliate Hospital of Sun Yat-sen University and the Industry-University-Research Cooperation Program from Science and Technology Department of Guangdong Province (No:2010B090400533)
文摘A reversed phase high performance liquid chromatography (HPLC) method was established for the simultaneous determination of 12,13-dihydroxyeuparin and glycyrrhizic acid in Yanyanfang mixture.A Grace Apollo C 18 column (250 mm 4.6 mm,5 mm) was used as the stationary phase and the mobile phase was composed of acetonitrile and aqueous phosphoric acid (0.2%,v/v).Gradient elution was carried out at the flow rate of 1.0 mL/min and the column temperature was 30 1C.An ultraviolet (UV) detector was used with a selected wavelength of 240 nm.Calibration curves were linear within the concentration range of 4.6-45.75 mg/mL for 12,13-dihydroxyeuparin (r40.9999) and 106.9-1068.9 mg/mL for glycyrrhizic acid (r40.9999),respectively.Recoveries were 102.18% for 12,13-dihydroxyeuparin and 101.17% for glycyrrhizic acid.The method developed could be applied to the simultaneous determination of 12,13dihydroxyeuparin and glycyrrhizic acid in Yanyanfang mixture.
文摘Context: Metformin is frequently prescribed for the treatment of type 2 diabetes mellitus. It is recommended as a first line agent by the American Diabetes Association. Vitamin B12 deficiency has been suggested as a side effect of metformin therapy;however, previous studies have not assessed the utility of methylmalonic acid levels as an indicator of vitamin B12 status. Objective: To investigate the prevalence of vitamin B12 deficiency in patients on metformin therapy for diabetes by utilizing both vitamin B12 and methylmalonic acid levels. Design, Setting, and Patients: Eighty-eight patients with diabetes, who were either on or off metformin therapy for at least thirty days, were enrolled in a case-controlled study. Blood work and questionnaires were used for analysis. Main Outcome Measures Study: Aims were to detect a clinically significant difference in the prevalence of vitamin B12 deficiency between metformin users and non-users, where such deficiency is defined by both low vitamin B12 and elevated methylmalonic acid levels. Results: Two Sample Equal Variance T-Tests were used to compare averages of measured values and the Chisquare test was used to determine the significance of calculated vitamin B12 deficiency rates between the two groups of patients. Two separate methods for defining vitamin B12 deficiency were utilized. There was no difference in the prevalence of vitamin B12 deficiency in metformin users compared with non-users by either method. Average homocysteine levels were higher in those not on metformin therapy. Conclusion: Vitamin B12 deficiency as defined by an elevated methylmalonic acid level was no greater in patients with diabetes on metformin therapy versus those patients not on metformin treatment.
基金Funded by the Natural Science Foundation of Hubei Province (No.2005ABA053)Hubei Key Laboratory of Pollutant Analysis & Reuse Technologythe National Natural Science Foundation of China (No. 20471044)
文摘A novel environmental friendly catalyst, H4SiW12O40/PAn was prepared and identified by FT-IR, XRD and TG/DTA. The optimal synthetic protocol was a PAn to H4SiW12O40 mass ratio of 1∶1, a 20 mL of methanol and a reaction time of 2 h at reflux. It was used in catalytic synthesis of ten important ketals and acetals with a high catalytic activity. With an aldehyde/ketone to glycol molar ratio of 1∶1.5 and a 1 wt% catalyst loading, the yields of ketals and acetals could reach 60.0%-93.8 % after 1 h.
