| 1 | Optical properties of estuarine dissolved organic matter isolated using cross-flow ultrafiltration显示文摘Dissolved organic matter(DOM) from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter(COM; 10 kDa–0.22 μm) retentate, low molecular weight(LMW) DOM(<10 kDa) permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM(CDOM, expressed as the absorption coefficient a355) occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmember(13.4% of the total) than in the seawater endmember(6.8%). The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components(C1: <250, 325/402 nm; and C2: 265, 360/458 nm) and one protein-like component(C3: 275/334 nm) were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%–8.7%, 4.8%–12.6%, and 7.4%–14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/(C1+C2) was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component(C3) to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM. | YI Yueyuan ZHENG Airong GUO Weidong YANG Liyang CHEN Ding | 2014 | Acta Oceanologica Sinica2014，33，4： | 6 |
| 2 | A novel o-nitrobenzyl-based photocleavable antitumor prodrug with the capability of releasing 5-fluorourail显示文摘An o-nitrobenzyl-based photocleavable antitumor prodrug with a terminal carboxyl group was designed and synthesized.The photolysis properties of the prodrug were investigated by means of1H NMR,HPLC,UV,and MTT methods.The results showed that the toxicity of the anticancer drug was effectively shielded before release.However,the prodrug effectively regained the antitumor capability against cancer cells by release of 5-fluorouracil when it was exposed to ultraviolet irradiation. | Shuli Mo Ying Wen Fengfeng Xue Haichuang Lan Yueyuan Mao Guanglei Lv Tao Yi | 2016 | Science Bulletin2016，61，6： | 2 |
| 3 | Formation and regulation of supramolecular chirality in organogel via addition of tartaric acid显示文摘A new 1,8-naphthalimide derivative was prepared in which the C-4 position was substituted by pyridin-4-ol.This derivative shows good gelation property that can gelate most of polar solvents.As an achiral molecule,helical fibre morphology was observed when the compound gelated acetone solvent.When 0.5 eq of D-tartaric acid or L-tartaric acid was added to the gel,the helical morphology was changed from left-handed to right-handed structure.This result was further proved by circular dichroism measurement.FT-IR experiment showed the formation of intermolecular H-bond between the gelator and tartaric acid.The photophysical properties of gelator had no difference before and after addition of tartaric acid;whereas the lamellar structure was varied by addition of tartaric acid. | CAO XinHua ZHANG MingMing LIU KeYin MAO YueYuan LAN HaiChuang LIU Bin YI Tao | 2012 | Chinese Science Bulletin2012，57，33： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员