Pt和Sb、S吸附原子修饰的Pt电极上正丙醇氧化的CV和EQCM研究

运用电化学循环伏安法和石英晶体微天平研究了正丙醇在Pt电极和以Sb、S吸附原子修饰的Pt（Pt/Sbad和Pt/Sad）电极上的吸附和氧化过程.从电极表面质量变化角度指出正丙醇的氧化与电极表面氧物种有着极其密切的关系.Pt电极表面Sb吸附原子能在较低的电位下吸附氧，可显著提高正丙醇电催化氧化活性，与在Pt电极上相比较,正丙醇氧化的峰电位负移了0.29 V,峰电流增加了近2倍.相反,Pt电极表面S吸附原子的氧化会消耗表面氧物种，饱和吸附S原子的Pt电极上正丙醇的电氧化受到抑制.本文从表面质量变化提供了吸附原子电催化作用的新数据.     

The Anti-Apoptotic Effects of Caspase Inhibitors in Propyl Gallate-Treated Lung Cancer Cells Are Related to Changes in Reactive Oxygen Species and Glutathione Levels

Propyl gallate [3,4,5-trihydroxybenzoic acid propyl ester; PG] exhibits an anti-growth effect in various cells. In this study, the anti-apoptotic effects of various caspase inhibitors were evaluated in PG-treated Calu-6 and A549 lung cancer cells in relation to reactive oxygen species (ROS) and glutathione (GSH) levels. Treatment with 800 μM PG inhibited the proliferation and induced the cell death of both Calu-6 and A549 cells at 24 h. Each inhibitor of pan-caspase, caspase-3, caspase-8, and caspase-9 reduced the number of dead and sub-G1 cells in both PG-treated cells at 24 h. PG increased ROS levels, including O₂^∙−, in both lung cancer cell lines at 24 h. Generally, caspase inhibitors appeared to decrease ROS levels in PG-treated lung cancer cells at 24 h and somewhat reduced O₂^∙− levels. PG augmented the number of GSH-depleted Calu-6 and A549 cells at 24 h. Caspase inhibitors did not affect the level of GSH depletion in PG-treated A549 cells but differently and partially altered the depletion level in PG-treated Calu-6 cells. In conclusion, PG exhibits an anti-proliferative effect in Calu-6 and A549 lung cancer cells and induced their cell death. PG-induced lung cancer death was accompanied by increases in ROS levels and GSH depletion. Therefore, the anti-apoptotic effects of caspase inhibitors were, at least in part, related to changes in ROS and GSH levels.     

(2-羟基-3-丁氧基)丙基-羟丙基壳聚糖的应用性质

表面活性;泡沫性;乳化性;吸湿保湿性;(2-羟基-3-丁氧基)丙基-羟丙基壳聚糖的应用性质     

3-(2′-乙氧基乙氧基)丙基锂的合成

3-(2′-乙氧基乙氧基)丙基锂的合成;阴离子聚合引发剂;(乙氧乙氧基)丙基锂;高真空反应器     

Chloro-bis-propyl Ethers in the Elbe River – Isomeric Distribution and Enantioselective Degradation

Cyclodextrin derivatives are evaluated as chiral stationary phases for the enantiomer separation of chlorinated bis(propyl) ethers (BPE). The enantiomeric composition of the 2,3,2′,3′- and 1,3,2′,3′-isomers of tetrachlorobis(propyl) ether in the Elbe River has been quantitatively determined by enantioselective gas chromatography and coupled gas chromatography/mass spectrometry in selected-ion-monitoring mode. Significant enantiomeric discriminations are observed in selected water samples, indicating that enantioselective bio-degradation mechanisms are at least partly responsible for the overall degradation processes.     

Separation and Determination of Phenolic Antioxidants by HPLC with Surfactant/n‐Propanol Mobile Phases

The influence of cationic and anionic surfactants and short‐chain alcohols in the mobile phase on the retention of five antioxidants has been studied. The solutes chosen were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl, octyl, and dodecyl gallates (PG, OG, DG).The surfactants were hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), and n‐propanol (PrOH) was the selected alcohol. A simple isocratic reversed‐phase method for the antioxidant determination is proposed. Separation of five primary antioxidants takes 18 min with the mobile phase SDS 0.10 M/H₃PO₄ 0.01 M/PrOH 30%. Variation of the percentage of alcohol in the mobile phase permits optimization of the retention times of the antioxidants. Detection limits in the pg range were obtained for the all solutes. The method was used to determine the antioxidants in olive oil at three different levels, giving mean recoveries close to 100% for all the solutes (BHA 102%, PG 99%, OG 99%, DG 99%) except BHT (84%).     

Collagen-EGCG Combination Synergistically Prevents UVB-Induced Skin Photoaging in Nude Mice

Ultraviolet (UV) radiation is a major cause of skin photoaging through generating excessive oxidative stress and inflammation. One of the strategies is to use photo-chemoprotectors, such as natural products with antioxidant and anti-inflammatory properties, to protect the skin from photo damage. The present study investigates the photoprotective potentials of topical administration of unhydrolyzed collagen, epigallocatechin gallate (EGCG), and their combination against ultraviolet B (UVB)-induced photoaging in nude mice. It is found that both the solo and combined pretreatments could recover UVB-induced depletion of antioxidative enzymes, including superoxide dismutase and glutathione peroxidase (GSH-Px), as well as an increase of lipid peroxide malondialdehyde and inflammatory tumor necrosis factor-α. Meanwhile, the UVB-stimulated skin collagen degradation is attenuated significantly with drug treatments, which is evidenced by expression analysis of matrix metalloproteinase-1 and hydroxyproline. Additionally, the mouse skin histology shows that the drug-pretreated groups possess decreased epidermis thickness and normal collagen fiber structure of the dermis layer. These results demonstrate that both EGCG and collagen can protect the skin against UVB-induced skin photoaging. Synergistically, the combination of them shows the maximum prevention to skin damage, showing its potential in the application of anti-photoaging formulation products.     

Selective adsorption of epigallocatechin gallate onto highly reusable gallium doped mesoporous TiO2 nanoparticles adsorbent

This work describes a potential selective adsorption of epigallocatechin gallate by Ga-doped TiO₂ nanoparticles (NPs) and showed excellent adsorption (～99%) and desorption capacity even after the 7th run. The work reports about a surfactant mediated template based synthesis of both pristine and Ga-doped TiO₂ mesoporous NPs to study the adsorption behavior EGCG. EGCG is the most abundant and bio-active compound capable of showing free radical scavenging activity, anticancer, antibacterial, and several other physiological functions. Therefore, extraction of EGCG is highly desirable for incorporation in food items that can effectively increase their nutritional and medicinal values. The pore diameter of the synthesized materials was found to be in the range 8.76–10.38 nm and the specific surface area was found to be around 25.80–58.72 m²/g. The particle size decreased from 25 nm to 15 nm in presence of Ga. A mixture of anatase and brookite phase was observed for all the synthesized TiO₂ NPs. The band gap value initially (3.40 eV) decreased in presence of minute amounts of Ga (3.44 eV) but then increased (3.59 eV) with the increase of Ga percentage. The point of zero charge (PZC) value of the materials lies in the range of 6.6–7.2. The adsorption study was carried out at different pH (1, 3, 5, 7 and 9) with variation of shaking time (1 h, 3 h, 5 h and 7 h). The material containing maximum Ga in the Ga-doped set (Set 3 TiO₂ NPs) showed highest adsorption percentage (99.45%) in pH 1 medium after 5 h shaking. The adsorption isotherm and the kinetics follow the Langmuir model and pseudo-second order respectively. Desorption was studied under high energy gamma rays, shaking, sonication and UV irradiation. The highest desorption (～96%) was obtained with sonication for 30 min.     

Adsorptive Separation of Acetylene from Ethylene in Isostructural Gallate-Based Metal–Organic Frameworks

The separation of acetylene from ethylene is of paramount importance in the purification of chemical feedstocks for industrial manufacturing. Herein, an isostructural series of gallate-based metal–organic frameworks (MOFs), M-gallate (M=Ni, Mg, Co), featuring three-dimensionally interconnected zigzag channels, the aperture size of which can be finely tuned within 0.3 Å by metal replacement. Controlling the aperture size of M-gallate materials slightly from 3.69 down to 3.47 Å could result in a dramatic enhancement of C₂H₂/C₂H₄ separation performance. As the smallest radius among the studied metal ions, Ni-gallate exhibits the best C₂H₂/C₂H₄ adsorption separation performance owing to the strongest confinement effect, ranking after the state-of-the-art UTSA-200a with a C₂H₄ productivity of 85.6 mol L⁻¹ from 1:99 C₂H₂/C₂H₄ mixture. The isostructural gallate-based MOFs, readily synthesized from inexpensive gallic acid, are demonstrated to be a new top-performing porous material for highly efficient adsorption of C₂H₂ from C₂H₄.