Simultaneous quantitation of seven alkaloids in processed Fuzi decoction by rapid resolution liquid chromatography coupled with tandem mass spectrometry

A rapid analytical method based on rapid resolution LC coupled with MS/MS was first established to quantify seven alkaloids in processed Fuzi decoction. The chromatographic method was optimized to allow simultaneous analysis of all analytes in 5 min and demonstrated good linearity (r > 0.9995), repeatability (RSD < 4.36%), intra‐ and interday precisions (RSD < 5.07%) with good accuracies (97.76–105.08%) and good recovery (95.0–107.5%) of seven alkaloids, namely higenamine, benzoylhypaconine, benzoylmesaconine, benzoylaconine, aconitine, hypaconitine, and mesaconitine. The LODs for these markers were in the range of 2.30–17.00 pg/mL. Quantitative analysis of the seven alkaloids in Baifupian decoction and Heishunpian decoction showed that the content of the seven marker chemicals varied significantly and concluded that the quality of Fuzi was greatly affected by different processed methods. The developed method could be used as a rapid, sensitive, and reliable approach for assessment of the quality of processed Fuzi and related decoction.     

Chemoselective Removal of Acyloxy in 1-(Benzotriazole-1-yl)alkyl Esters and Its Application in the Preparation of β-(Benzotriazole-1-yl)alcohols

Mediated by samarium diiodide, 1-(benzotriazole-1-yl)alkyl esters 1 underwent cross-coupling with aldehydes or ketones to afford β-(benzotriazole-1-yl)alcohols 2 exclusively with the selective removal of acyloxy over benzotriazolyl.     

Solubility of Icariin in a Binary Solvent System of Ethanol and Water

The solubility of icariin in the binary solvent system of ethanol and water was measured by UV–Vis spectrophotometry from 288.2 to 328.2 K. The solubility of icariin in the system increased with increasing temperature. A synergistic effect appeared at x ₂ = 0.4 (equivalent to 68.34 % ethanol, v/v) binary mixture. Solubility data were correlated with the modified Apelblat equation. The enthalpy and entropy of solution were evaluated using van’t Hoff plots.     

Effect of partial crosslinking on morphology and properties of the poly(β-hydroxybutyrate)/poly(d,l-lactic acid) blends

Poly(β-hydroxybutyrate) (PHB) is a bio-based and biodegradable aliphatic polyester, however its application is limited by some disadvantages such as high price, brittleness, poor processability and low melt-strength due to serious thermal degradation. Partial crosslinking initiated by dicumyl peroxide (DCP) was applied in this work to improve the performance of poly(β-hydroxybutyrate)/poly(d,l-lactic acid) (PHB/PDLLA) blends. The partial crosslinking of the blends and its effect on the properties, morphology, rheology and thermal behavior of the blends were investigated. The tensile strength and impact toughness of the PHB were increased by incorporation of the PDLLA, which were improved further after the partial crosslinking because of an increased compatibility between the PHB and the PDLLA phases. The rheological study revealed that the storage modulus (G′) and complex viscosity (η*) of the blends were increased after addition of the DCP. On the other hand, the crystallization of PHB in the blends was restricted to a certain extent by the formation of partially crosslinked network while its crystal form was not modified.     

酸碱解聚玉米秸秆分子结构的实验研究

以玉米秸秆为研究对象,分别采用5%H2SO4和5%NaOH溶液对秸秆进行解聚处理,并对解聚前后秸秆结构、化学组成、热稳定性等进行分析和表征。结果表明,与未处理前相比,经酸或碱解聚处理后,秸秆纤维结晶度由51.8%分别提高到63.5%和67.0%,秸秆中大部分半纤维素和部分木质素组分被脱除,半纤维素由29.10%分别降至7.02%和6.86%,木质素由38.12%分别降至32.21%和16.52%,而纤维素则由31.54%分别升至60.54%和76.15%。经酸碱处理后,秸秆表面形态结构变得疏松,出现小孔和裂缝,降解温度达到350℃,热稳定性能增加。上述结果说明,稀酸或稀碱均对玉米秸秆分子结构有一定程度的解聚作用,但就解聚溶出木质素而言,稀碱的解聚溶出效果要优于稀酸的。     

顺铂耐药的分子机制

顺铂被广泛用于多种类型的实体肿瘤的临床治疗.DNA是顺铂的主要靶点,顺铂结合会导致DNA损伤并诱发细胞凋亡.然而,顺铂化疗常常受到内在的和获得性的耐药性的限制.在过去30多年里,大量的研究致力于对顺铂耐药性的理解,并且提出了几种导致顺铂耐药性的分子机制.这些机制显示顺铂的耐药性具有多因素特征.本文系统描述和讨论了顺铂的耐药性机制,包括细胞内药物积累的减少,药物去活作用的增强,DNA修复作用,DNA损伤反应和凋亡通路的变化以及一些间接信号通路的调控影响.     

Highly Efficient Orange and Warm White Phosphorescent OLEDs Based on a Host Material with a Carbazole–Fluorenyl Hybrid

A new carbazole–fluorenyl hybrid compound, 3,3′(2,7‐di(naphthaline‐2‐yl)‐9H‐fluorene‐9,9‐diyl)bis(9‐phenyl‐9H‐carbazole) (NFBC) was synthesized and characterized. The compound exhibits blue‐violet emission both in solution and in film, with peaks centered at 404 and 420 nm. In addition to the application as a blue emitter, NFBC is demonstrated to be a good host for phosphorescent dopants. By doping Ir(2‐phq)₃ in NFBC, a highly efficient orange organic light‐emitting diode (OLED) with a maximum efficiency of 32 cd A^?1 (26.5 Lm W^?1) was obtained. Unlike most phosphorescent OLEDs, the device prepared in our study shows little efficiency roll‐off at high brightness and maintains current efficiencies of 31.9 and 26.8 cd A^?1 at a luminance of 1000 and 10 000 cd m^?2, respectively. By using NFBC simultaneously as a blue fluorescence emitter and as a host for a phosphorescent dopant, a warm white OLED with a maximum efficiency of 22.9 Lm W^?1 (21.9 cd A^?1) was also obtained.     

基于探针底物法的高效液相色谱-串联质谱法测定蚯蚓体内4种CYP同工酶活力及其应用北大核心CSCD

基于探针底物法,将蚯蚓微粒体悬浮液加入至含有混合探针底物香豆素(50μmol·L^(-1))、安非他酮(25μmol·L^(-1))、阿莫地喹(50μmol·L^(-1))、右美沙芬(5μmol·L^(-1))的孵育体系中(微粒体蛋白质量浓度需控制在32~96 mg·L^(-1)内),于37℃孵育20 min后,加入甲醇终止反应,静置10 min后过0.22μm滤膜,采用高效液相色谱-串联质谱法测定对应的代谢物7-羟基香豆素、羟基-安非他酮、N-脱乙基阿莫地喹、右啡烷的生成量。根据相应代谢物的生成量分别评价蚯蚓CYP2A6、CYP2B6、CYP2C8及CYP2D6酶活力。采用Acquity UPLC HSS T3柱作为分离柱,以不同体积比的含1 mmol·L^(-1)乙酸铵的0.05%(φ)甲酸溶液和甲醇的混合溶液作为流动相进行梯度洗脱,串联质谱中采用电喷雾离子源正离子模式和多反应监测模式检测,并用基质匹配法配制混合标准溶液系列。结果显示:7-羟基香豆素、羟基-安非他酮、N-脱乙基阿莫地喹、右啡烷的质量浓度均在2.5~50μg·L^(-1)内与其对应的峰面积呈线性关系;对空白样品进行3个浓度水平的加标回收试验,回收率为73.7%~103%,日内相对标准偏差(RSDs,n=5)为2.1%~11%,日间RSDs(n=5)为4.6%~10%。方法用于分析分别暴露于多壁碳纳米管染毒土壤(暴露组)和普通土壤(对照组)21 d后蚯蚓体内4种CYP同工酶的活力,CYP2C8酶活力明显高于CYP2A6、CYP2B6及CYP2D6,暴露组中CYP2A6及CYP2C8酶活力显著(P<0.05)高于对照组,而CYP2B6及CYP2D6酶活力与对照组的无显著性差异,因此推测可将CYP2A6及CYP2C8作为一套生物标记物,用于定性诊断土壤的多壁碳纳米管污染。     

基于PLC的模拟量闭环控制系统PID的实现

文章对模拟闭环控制系统的原理、变送器的选择方法及闭环控制系统主要性能指标进行了描述,介绍了PID控制器的数字化过程及PID指令向导生成PID程序的步骤,通过S7-200 SMART PLC编程实现该控制过程,并进行了参数整定,达到了控制效果。