Preparation and Intestinal Immunostimulating Activity of Low Molecular Weight Alginate from Saccharina (Laminaria) Species in Japan

We studied the structure of alginates extracted from five commercial Saccharina (Laminaria) species including three varieties (eight samples in all) harvested in Hokkaido, Japan. The algae used were Saccharina japonica, S. japonica var. diabolica, S. japonica var. ochotensis, S. japonica var. religiosa, S. longissima, S. coriacea, S. angustata, and S. sculpera (Kjellmaniella crassiforia). These alginates have molar fractions of mannuronic acid (F_M) ranging from 0.68 to 0.76 and weight average molecular weights (M_ws) ranging from 511,000 to 616,000. Alginate samples from both S. angustata (F_M = 0.76) and S. longissima (F_M = 0.68) showed intestinal immunological activity through Peyer’s patch cells of C3H/HeJ mice. Low molecular weight S. angustata alginate (F_M = 0.75, M_w = 70,000) degraded using a wet pulverizing system showed higher activity than the native one.     

Side chain effect on photovoltaic properties of dibenzo[a,c]phenazine based donor–acceptor polymers

The electron–donor polymers containing dibenzo[a,c]phenazine (BPz) derivatives with 2,7-alkyl and 11,12-alkoxy substituted, PBDT-BPzC and PBDT-OBPz, respectively, were synthesized to investigate the photovoltaic effect of different side chain substitutions. The polymers exhibit similar physical properties, except the HOMO and LUMO of PBDT-BPzC are 0.18 and 0.15 eV deeper than PBDT-OBPz, resulting in the V_oc of polymer solar cells (PSCs) based on PBDT-BPzC are above 0.1 V higher than that of PBDT-OBPz. With the contribution of the superior V_oc, polymer PBDT-BPzC showed preferable photovoltaic performances, and the PCE reached 4.44%, which is 0.49% higher than PBDT-OBPz. This research reveals a preferred side chain substituted way to modify BPz unit, and gives an optimally developing the dibenzo[a,c]phenazine derivatives based electron–donor polymers.     

运用空腔效应选择煤衍生油提酚萃取剂

为缩小煤衍生油提酚萃取剂的筛选范围,减少试验次数,对富含酚类化合物的典型煤衍生油进行单体酚分析及中性油组分的定性分析,运用空腔效应和键能数据相结合的方法在众多有机溶剂中进行煤衍生油提酚萃取剂的筛选,通过计算得出萃取过程中消耗的能量,缩小筛选范围。结果表明,典型煤衍生油酚油馏分中酚类化合物主要以苯酚和甲酚等低级酚为主,中性油主要以茚和萘等单环或双环芳烃为主。烷烃和芳香烃类的惰性溶剂萃取时消耗能量-2~1 k J/mol,不适合作为煤衍生油提酚萃取剂。而醇类、羧酸类、醚类、酮类、胺类等与酚类化合物分子间存在氢键的溶剂萃取时消耗能量-80~20 k J/mol,初步筛选适合作为煤衍生油提酚萃取剂。醇类和羧酸类等分子内存在氢键的溶剂比醚类、酮类和胺类等分子间只存在范德华键的溶剂在萃取过程中需消耗更多的能量。     

浅谈导数在经济学中的应用

高等数学中的导数与经济学之间有密切的关系,运用导数理论在经济学中的应用进行研究,可以解决经济学中的一些常见问题。     

Safety assessment of thiolated polymers: effect on ciliary beat frequency in human nasal epithelial cells

Objective: The aim of this study was to investigate the nasal safety of gel formulations of thiolated polymers (thiomers) by assessing their effect on ciliary beat frequency (CBF) in human nasal epithelial cells.

Methods: Poly(acrylic acid) 450 kDa-cysteine (PAA-cys) and alginate-cysteine (alg-cys) were synthesized by covalent attachment of L-cysteine to the polymeric backbone. The cationic polymer chitosan-thiobutylamidine (chito-TBA) was synthesized by attaching iminothiolane to chitosan. CBF using was measured by a photometric system. CBF was measured before incubating the cells with test gels, during incubation and after washing out the polymeric test gels to evaluate reversibility of cilio-inhibition. The influence of viscosity on CBF was determined by using hydroxyethylcellulose (HEC)-gels of various concentrations.

Results: Ciliary beating was observed to be affected by viscosity, but cilia were still beating in the presence of a HEC-gel displaying an apparent viscosity of 25 Pa.s. In case of thiolated polymers and their unmodified control, a concentration-dependent decrease in CBF could be observed. PAA-cys, alg-cys, chito-TBA and their corresponding unmodified controls exhibited a moderate cilio-inhibitory effect, followed by a partial recovery of CBF when used at a concentration of 1%. Alg-cys 2% and chito-TBA 2% (m/v) gels exhibited severe cilio-inhibition, which was partially reversible. L-cysteine and reduced glutathione led to mild cilio-inhibition at concentrations of 3% (m/v).

Conclusions: Taking into account that dilution after application and cilio-modifying effects is usually more pronounced under in vitro conditions, thiomers can be considered as suitable excipients for nasal drug delivery systems.     

Preparation of chitosan-based flocculant for high density waste drilling mud solid–liquid separation

High performance flocculant was prepared by chitosan (CS), ethacryloyloxyethyl trimethyl ammonium chloride (DMC), and acrylamide (AM). The optimum preparation conditions were determined by orthogonal test of four factors and three levels. The different factors affecting the flocculating ability of the prepared flocculants for waste drilling mud were studied, and optimal synthesis conditions were established: polymerization temperature was 60, reaction time was 4 h, DMC was 3 mL, w(AM) : w(CS) was 4, and the initiator was 0.4% of AM (wt %). The prepared CS–AM–DMC copolymer was characterized by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and gel permeation chromatography (GPC). The results showed that AM, DMC were grafted to CS successfully. The solid–liquid separation properties were also investigated, and the prepared flocculant showed great advantages than commercial products for high density waste drilling mud use. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

理论力学点的合成运动体系教学探索及实践

为降低理论力学点的合成运动学习难度,对其教学方法进行了探索和实践.基于高等数学的有关概念和定理,分别采用极限法和导数法解析了点的合成运动的速度合成定理及加速度合成定理,首次提出了牵连导数的概念,并在教学实践中检验了两种方法的适用性.     

Squamosamide Derivative FLZ Protects Retinal Pigment Epithelium Cells from Oxidative Stress through Activation of Epidermal Growth Factor Receptor (EGFR)-AKT Signaling

Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is attributed to age-related macular degeneration (AMD) pathogenesis. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, Annona glabra, has displayed significant cyto-protective activity. In the current study, we explored the pro-survival effect of FLZ in oxidative stressed-RPE cells and studied the underlying signaling mechanisms. Our results showed that FLZ attenuated hydrogen peroxide (H₂O₂)-induced viability decrease and apoptosis in the RPE cell line (ARPE-19 cells) and in primary mouse RPE cells. Western blotting results showed that FLZ activated AKT signaling in RPE cells. The AKT-specific inhibitor, MK-2206, the phosphoinositide 3-kinase (PI3K)/AKT pan inhibitor, wortmannin, and AKT1-shRNA (short hairpin RNA) depletion almost abolished FLZ-mediated pro-survival/anti-apoptosis activity. We discovered that epidermal growth factor receptor (EGFR) trans-activation mediated FLZ-induced AKT activation and the pro-survival effect in RPE cells, and the anti-apoptosis effect of FLZ against H₂O₂ was inhibited by the EGFR inhibitor, PD153035, or by EGFR shRNA-knockdown. In conclusion, FLZ protects RPE cells from oxidative stress through activation of EGFR-AKT signaling, and our results suggest that FLZ might have therapeutic values for AMD.     

去甲去氢斑蝥素新衍生物的合成

以顺丁烯二酸酐和呋喃为起始原料,经Diels-Alder[4+2]缩合反应,制备去甲去氢斑蝥素,同时在去甲去氢斑蝥素分子中引入电负性较大的氧原子、氮原子。去甲去氢斑蝥素经SN2取代、缩合和过氧酸氧化三步反应,合成了5,6-环氧去甲去氢斑蝥素衍生物,去甲去氢斑蝥素经S_N2取代、缩合、过氧酸氧化和取代四步反应,得到5,6-二羟基去甲去氢斑蝥素衍生物。所得化合物均经~1HNMR和ESI-MS确证。