一类非等阶分数阶非线性系统的神经网络控制

讨论一类不确定非线性分数阶非等阶（noncommensurate）的系统的控制问题。假设系统含的不确定包括正实不确定（positive real uncertainty）项和非线性函数完全未知,首先利用RBF神经网络近似未知非线性函数,再基于系统的连续频率分布模型将分数阶系统转化为等价的无穷维分布状态变量的整数阶系统,结合间接Lyapunov方法及线性矩阵不等式（LMI）方法,给出了系统鲁棒渐近稳定的充分条件。理论和实例仿真验证了方法的有效性。     

保留盆腔神经宫颈癌根治术与传统宫颈癌根治术的比较研究

目的:探讨保留盆腔自主神经的宫颈癌根治术与传统宫颈癌根治术对患者术后生活质量的影响及其手术效果的初步评估。方法:选择皖南医学院第一附属医院2011年1月至2012年09月收治的经国际妇产科学联盟(FIGO)分期为ⅠB~ⅡA的子宫颈癌患者50例,设研究组(n=20)采用保留盆腔自主神经的宫颈癌根治术,对照组(n=30)行传统的宫颈癌根治术,比较两组手术范围、手术时间、术中出血量、导尿管保留天数、残余尿量、肛门排气、排便时间及术后半年性功能恢复情况。结果:对照组与研究组比较,术后第10天残余尿量分别为(201.83±83.00)、 (139.75±69.01) mL,保留尿管天数(15.20±2.43)、(11.85±2.08) d;术后肛门排气时间分别为(72.97±16.31)、(59.60±13.37) h,术后肛门排便时间分别为(121.17±23.07)、(91.05±11.66)h,两组相比差异具有统计学意义(P＜0.05);术后半年性功能随访结果显示:对照组性功能障碍的发生率为 86.7%,研究组性功能障碍发生率为45%,两组相比差异有统计学意义(P＜0.05),对术后半年未恢复性生活的患者进行原因调查,发现因“害怕疾病复发”占 77.8%;害怕“性交痛或出血”占 55.6%。研究组与对照组手术时间中位数分别为250(180~330) min 和200(150~270) min,术中手术时间、出血量、术中切除主骶韧带、阴道长度及淋巴结清扫数目等指标差异均无统计学意义。结论:保留盆腔自主神经的宫颈癌根治术治疗早期宫颈癌是安全可行的,与传统根治术相比更有利于膀胱、直肠功能的恢复,有助于提高患者术后的生活质量。     

Phenolic compounds and the biological effects of Pu-erh teas with long-term storage

Pu-erh tea has gained more and more popularity and attracted much attention for its various biological effects. The objective of this study was to determine the active phenolic compounds and the biological effects of 15 differently aged Pu-erh teas. The results showed that 43 active phenolics, containing 7 flavan-3-ols, 11 organic acids, and esters, 3 proanthocyanidin dimers, 2 benzotropolones, and 20 flavonoid glycosides were identified based on high-performance liquid chromatography coupled to electrospray ionisation and quadrupole time-of-flight tandem mass spectrometry (HPLC-ESI-QTOF-MS/MS). In particular, 2’-O-galloylhyperin and quercetin-3-O-p-coumaroyl-rhamnosyl-arabinosyl-hexoside were identified from constituents of tea for the first time. The 15 Pu-erh teas exhibited strong DPPH and ABTS scavenging activity in a concentration-dependent manner with IC₅₀ 0.99–2.12 and 0.97–2.67 mmol Trolox equivalent antioxidant capacity/g, respectively. All of the Pu-erh teas tested significantly inhibited the proliferation of SMMC-7721 cells, in a dosage-dependent manner. Of the 15 Pu-erh teas examined, the cake tea P6 had the strongest effect on SMMC-7721 cells with IC₅₀ = 65.88 ± 3.53 µg/mL. The others Pu-erh teas had an IC₅₀ = 96 – 509 µg/mL. Our results also indicated that not all the older Pu-erh teas display stronger anti-activities and anti-cancer than the younger ones and the youngest Pu-erh tea did not possess the highest level of active components. This study provides useful information for consumers to deeply understand the chemical constituents and bioactivity of Pu-erh tea preserved for a long time.     

Fatty Acid Composition, Antioxidant Properties, and Antiproliferative Capacity of Selected Cold-Pressed Seed Flours

Cold-pressed seed flours from pumpkin, parsley, mullein, cardamom, and milk thistle were examined for total oil, fatty acid profile of the oil, total phenolic content (TPC), scavenging activities against peroxyl (ORAC), hydroxyl (HOSC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (RDSC) radicals, and antiproliferative capacity against HT-29 human colon cancer cells. The cold-pressed parsley seed flour contained a very high concentration of total oil—17.6 g/100 g flour—with primarily C18:1 fatty acid at 86.2 g/100 g fatty acids. All other flour oils had relatively high levels of saturated fats, ranging from 39.0 to 62.9 g/100 g fatty acids. The tested seed flours demonstrated significant TPC and free radical scavenging activities. Milk thistle seed flour had the highest TPC value of 25.2 mg gallic acid equivalent per g flour (GAE mg/g) followed by that of parsley seed flour at 8.1 GAE mg/g. Milk thistle seed-flour extract also had significantly higher antioxidant activities than all other extracts against all tested radicals. The milk thistle seed-flour extract had an ORAC value of 1131 μmol trolox equivalents (TE) per g flour (TE μmol/g), a HOSC value of 893 TE μmol/g, and an RDSC value of 61 TE μmol/g. Also, ORAC, HOSC, and TPC values were significantly correlated (P < 0.01) under the experimental conditions. The cold-pressed milk thistle seed flour inhibited the proliferation of HT-29 cancer cells in a dose-dependent manner. Results from this study suggest that these cold-pressed seed flours may serve as natural sources of antioxidants and may be used to improve human health.     

高交联度易加工硅烷交联管材专用料的研制

介绍了采用二步硅烷交联工艺制备高交联度易加工硅烷交联管材专用料的方法,讨论了基础树脂、助剂对专用料交联度和加工性能的影响;通过加入自由基捕捉剂的方法,抑制接枝反应过程中的碳-碳大分子交联,解决了二步法硅烷交联领域的技术瓶颈问题,使硅烷交联管材专用料既具有高的交联度又具有良好的加工性能.     

Photoassisted oxypolymerization of alkyd resins: Kinetics and mechanisms

A new three-component system for photoassisted oxypolymerization of alkyd resins containing a drier, a photosensitizer and a radical generator was investigated. Polymerization profiles were recorded by real-time infrared spectroscopy for a thin film exposed for 1 h to simulated sunlight radiation. The kinetic results showed that the system follows complex kinetics. Multiple regression analysis was used to model the influence of the drier, the photosensitizer and the radical generator on the final conversion and total polymerization rate during photooxidation. The mechanisms involved were studied through laser spectroscopies. Laser flash photolysis was used to measure the rate constants of reaction between the radicals formed from the photodissociation of the radical generator and the model compounds of alkyd resins, leading to the rapid formation of hydroperoxides. The photosensitizer was expected to produce singlet state molecular oxygen that reacts on the alkyd resin, and time-resolved chemiluminescence technique was used to determine the quenching rate constant of singlet oxygen by model compounds. On the basis of these results, a mechanism for the photoassisted oxypolymerization of alkyd resins is proposed that account for the all the different reaction pathways.     

New nitrogen-containing bromophenols from the marine red alga Rhodomela confervoides and their radical scavenging activity

In addition to nine known bromophenol derivatives, five new nitrogen-containing bromophenols were isolated from an ethyl acetate extract of the marine red alga Rhodomela confervoides. By using spectroscopic methods, the structures of the new compounds were identified as 3-(2,3-dibromo-4,5-dihydroxybenzyl)pyrrolidine-2,5-dione (1), methyl 4-(2,3-dibromo-4,5-dihydroxybenzylamino)-4-oxobutanoate (2), 4-(2,3-dibromo-4,5-dihydroxybenzylamino)-4-oxobutanoic acid (3), 3-bromo-5-hydroxy-4-methoxybenzamide (4), and 2-(3-bromo-5-hydroxy-4-methoxyphenyl)acetamide (5). All of these bromophenols showed potent scavenging activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, with IC(50) values ranging from 5.22 to 23.60μM. These compounds also displayed moderate activity against ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonate) radicals, with Trolox Equivalent Antioxidant Capacity values (TEAC) ranging from 2.11 to 3.58mM. The results obtained in this study demonstrate that the bromophenols obtained from R. confervoides may have potential application in food and/or pharmaceutical fields as natural antioxidants.     

Inhibition of hemoglobin-mediated lipid oxidation in washed fish muscle by cranberry components

Fractions enriched in phenolic acids (Fraction 1), anthocyanins (Fraction 2), flavonols (Fractions 3 and 4) and proanthocyanidins (Fractions 5 and 6) were prepared from cranberry powder using Sephadex LH-20 chromatography. Fractions 2, 3, 4, and 5 had nearly equivalent reactivity in the total phenolate assay employed per mg dry weight of each fraction while Fractions 1 and 6 were less reactive. The ability of cranberry fractions to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals as well as their inhibitory effects on hemoglobin (Hb)-mediated lipid oxidation in washed cod muscle were assessed. Addition of cranberry fractions at a level of 74 μmol quercetin equivalents per kg of washed cod muscle extended the induction time of thiobarbituric acid reactive substances (TBARS) formation in the order: Fraction 1, Fraction 3, Fraction 4 > Fraction 2 > Fraction 5 > Fraction 6. This suggests that oligomeric polyphenols (e.g., proanthocyanidins) were least effective at inhibiting Hb-mediated lipid oxidation in washed cod muscle compared to the other classes of polyphenolics in cranberry. The ability of the different cranberry fractions to scavenge DPPH radicals did not reflect their relative ability to inhibit lipid oxidation in the washed cod muscle system. Quercetin was tentatively identified as a component in cranberry that was especially effective at inhibiting Hb-mediated lipid oxidation. The ability of flavonol and proanthocyanidin-enriched fractions to inhibit Hb-mediated lipid oxidation in spite of efforts to wash away the added polyphenolics prior to Hb addition indicated these classes of polyphenolics had binding affinities for insoluble components of washed cod muscle.     

Evaluation of reducing power and radical scavenging activities of water and ethanol extracts from sumac (Rhus coriaria L.)

The purpose of this study was to determine the reducing power, metal chelating, and radical scavenging capabilities of water and ethanol extracts of sumac (Rhus coriaria L.), comparatively. The water and ethanol extracts of sumac were evaluated for their radical scavenging activities by means of the DPPH and DMPD assays. Water extract of sumac (R. coriaria L.) scavenged radicals effectively with EC₅₀ values of 36.4 ??g/ml for DPPH free radical and 44.7 ??g/ml for DMPD cation radical. Similarly, the total reducing power of water extract was found higher than ethanol extract in both potassium ferricyanide reduction (FRAP) and cupric ions reduction capacity methods (CUPRAC). 2,2′-Bipyridine was used to determine the metal chelating activity and the result of water extract was found higher than ethanol extract. Total phenolic and total flavonoid contents of both extracts were studied as well. The values of water extract were found to be higher than that of ethanol extract. The present study found that water extracts of sumac (R. coriaria L.) have effective antioxidant and radical scavenging activities as compared to ethanol extracts.