Polysaccharides were extracted from Grateloupia livida(Harv.) Yamada using hot water(extracted product denoted WGW) and then degraded in dilute sulfuric acid(degraded product denoted WGWD). The degraded mixture was th...Polysaccharides were extracted from Grateloupia livida(Harv.) Yamada using hot water(extracted product denoted WGW) and then degraded in dilute sulfuric acid(degraded product denoted WGWD). The degraded mixture was then separated into four fractions through anion exchange chromatography on 2-diethylaminoethanol(DEAE)-Bio-Gel Agarose FF gel. Electrospray ionization collision-induced dissociation tandem mass spectrometry(ESI-CID-MS/MS) was performed to elucidate the structural features of all fractions. In combination with nuclear magnetic resonance spectroscopy(NMR)and infrared spectroscopy(IR) data, the major polysaccharide structures were concluded to be μ-carrageenan and κ-carrageenan. μ-Carrageenan usually has a backbone of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-6, while κ-carrageenan consists of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-3,6-anhydrogalactopyranose residues. Trace v-carrageenan, composed of 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-2 and C-6, was also detected. Furthermore, the polysaccharide had a backbone comprising 1,3-linked β-D-galactopyranose and1,4-linked α-L-galactopyranose sulfated at C-6, which is the agarose precursor. The hydroxy groups in the galactopyranose were partially substituted by methyl and pyruvic acid acetal(PA) groups. The anticomplementary activities of WGW and its derivatives against classical pathways were measured. The native polysaccharides in WGW had higher activities, while the derivatives had much weaker activities. This indicated that the molecular weight and sulfate content were important factors affecting the anti-complement activity.展开更多
Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spe...Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spectroscopic data, their structures were determined as： stigmast-4-en-3-one （Ⅰ）, cholest-4-en-3-one （Ⅱ）, cholesterol （m）, uracil （Ⅳ）, uridine （V）, adenosine （Ⅵ）, succinic acid （Ⅶ）, and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on （Ⅷ）. All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive （IC50 〉 10 μg/ml）.展开更多
[Objectives]This study was conducted to investigate the application of Sargassum fusiforme(Harv.)Setch.in cigarettes.[Methods]Tobacco-specific nitrosamines in the smoke of cigarettes added with ethanol extract of S.fu...[Objectives]This study was conducted to investigate the application of Sargassum fusiforme(Harv.)Setch.in cigarettes.[Methods]Tobacco-specific nitrosamines in the smoke of cigarettes added with ethanol extract of S.fusiforme were determined,and the compounds related to the aroma of S.fusiforme were identified by flavor-smelling experiment.[Results]With the addition of the ethanol extract of S.fusiforme,the decrease in the total amount of four tobacco-specific nitrosamines in mainstream cigarette smoke reached 16.42%.The results of the flavor-smelling experiment showed that the aroma of S.fusiforme might be related to(R)-5,6,7,7A-tetrahydro-4,4,7A-trimethyl-2(4H)-benzofuranone,glycerol,ethyl palmitate,methyl palmitate,ethyl linoleate,methyl(Z,Z,Z)-9,12,15-octadecatrienoate,ethyl(Z,Z,Z)-9,12,15-octadecatrienoate,phytol,and tetradecanoic acid.[Conclusions]The ethanol extract of S.fusiforme has the potential function of reducing the content of tobacco-specific nitrosamines in smoke and improving the taste of cigarettes.展开更多
Harvesting energy from ambient vibration sources with ultrathin flexible piezoelectric energy harvesters(PEHs)for battery-free electronics has received attention in recent years.However,the excitation modes in the env...Harvesting energy from ambient vibration sources with ultrathin flexible piezoelectric energy harvesters(PEHs)for battery-free electronics has received attention in recent years.However,the excitation modes in the environment and human body motion are more complicated than the ideal harmonic modes employed in previous theoretical analyses,and their influence on the efficiency of PEHs has received little attention.In this study,these environmental excitation modes are classified into three types,i.e.,the triangular,sinusoidal,and square wave modes,with varied duty ratios.We derived theoretically the output power of flexible PEHs under these excitation modes and establish a simple scaling law,in which the normalized output power depends only on two combined normalized parameters,i.e.,the intrinsic system parameter and the excitation mode.Results reveal that the output power of PEHs changes dramatically for different excitation modes with varied duty ratios even when all the other parameters including excitation ampli tude,excitation frequency,elec trical parameter,and geometrical and material parameters of the PEHs are identical.This paper may provide a systematic understanding in the effect of exc计ation modes on the output power of flexible PEHs and promote the realization of energy harvesting from the complex environmental and human body motions.展开更多
基金Supported by the Ocean Public Welfare Scientific Research Project(No.201405040)the National Science and Technology Support Project(No.2013BAB01B01)+1 种基金the Special Fund for Cooperation between Guangdong Province and Chinese Academy of Sciences(No.2012B090400028)the Science and Technology Program of Applied Basic Research Projects of Qingdao(No.15-9-1-74-jch)
文摘Polysaccharides were extracted from Grateloupia livida(Harv.) Yamada using hot water(extracted product denoted WGW) and then degraded in dilute sulfuric acid(degraded product denoted WGWD). The degraded mixture was then separated into four fractions through anion exchange chromatography on 2-diethylaminoethanol(DEAE)-Bio-Gel Agarose FF gel. Electrospray ionization collision-induced dissociation tandem mass spectrometry(ESI-CID-MS/MS) was performed to elucidate the structural features of all fractions. In combination with nuclear magnetic resonance spectroscopy(NMR)and infrared spectroscopy(IR) data, the major polysaccharide structures were concluded to be μ-carrageenan and κ-carrageenan. μ-Carrageenan usually has a backbone of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-6, while κ-carrageenan consists of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-3,6-anhydrogalactopyranose residues. Trace v-carrageenan, composed of 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-2 and C-6, was also detected. Furthermore, the polysaccharide had a backbone comprising 1,3-linked β-D-galactopyranose and1,4-linked α-L-galactopyranose sulfated at C-6, which is the agarose precursor. The hydroxy groups in the galactopyranose were partially substituted by methyl and pyruvic acid acetal(PA) groups. The anticomplementary activities of WGW and its derivatives against classical pathways were measured. The native polysaccharides in WGW had higher activities, while the derivatives had much weaker activities. This indicated that the molecular weight and sulfate content were important factors affecting the anti-complement activity.
基金the Project NNSF of China (No. 30530080 and 20432030)the New Century Excellent Talent Supporting Program of Chinese Ministry of Education
文摘Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spectroscopic data, their structures were determined as： stigmast-4-en-3-one （Ⅰ）, cholest-4-en-3-one （Ⅱ）, cholesterol （m）, uracil （Ⅳ）, uridine （V）, adenosine （Ⅵ）, succinic acid （Ⅶ）, and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on （Ⅷ）. All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive （IC50 〉 10 μg/ml）.
文摘[Objectives]This study was conducted to investigate the application of Sargassum fusiforme(Harv.)Setch.in cigarettes.[Methods]Tobacco-specific nitrosamines in the smoke of cigarettes added with ethanol extract of S.fusiforme were determined,and the compounds related to the aroma of S.fusiforme were identified by flavor-smelling experiment.[Results]With the addition of the ethanol extract of S.fusiforme,the decrease in the total amount of four tobacco-specific nitrosamines in mainstream cigarette smoke reached 16.42%.The results of the flavor-smelling experiment showed that the aroma of S.fusiforme might be related to(R)-5,6,7,7A-tetrahydro-4,4,7A-trimethyl-2(4H)-benzofuranone,glycerol,ethyl palmitate,methyl palmitate,ethyl linoleate,methyl(Z,Z,Z)-9,12,15-octadecatrienoate,ethyl(Z,Z,Z)-9,12,15-octadecatrienoate,phytol,and tetradecanoic acid.[Conclusions]The ethanol extract of S.fusiforme has the potential function of reducing the content of tobacco-specific nitrosamines in smoke and improving the taste of cigarettes.
文摘Harvesting energy from ambient vibration sources with ultrathin flexible piezoelectric energy harvesters(PEHs)for battery-free electronics has received attention in recent years.However,the excitation modes in the environment and human body motion are more complicated than the ideal harmonic modes employed in previous theoretical analyses,and their influence on the efficiency of PEHs has received little attention.In this study,these environmental excitation modes are classified into three types,i.e.,the triangular,sinusoidal,and square wave modes,with varied duty ratios.We derived theoretically the output power of flexible PEHs under these excitation modes and establish a simple scaling law,in which the normalized output power depends only on two combined normalized parameters,i.e.,the intrinsic system parameter and the excitation mode.Results reveal that the output power of PEHs changes dramatically for different excitation modes with varied duty ratios even when all the other parameters including excitation ampli tude,excitation frequency,elec trical parameter,and geometrical and material parameters of the PEHs are identical.This paper may provide a systematic understanding in the effect of exc计ation modes on the output power of flexible PEHs and promote the realization of energy harvesting from the complex environmental and human body motions.
