鸡骨素及其酶解液的美拉德反应产物挥发性风味成分比较分析

利用固相微萃取/气相色谱-质谱(SPME/GC-MS)联用与电子鼻(E-Nose)嗅探技术对鸡骨素美拉德反应产物(MRPs1)及鸡骨素酶解液美拉德反应产物(MRPs2)中的挥发性风味成分进行比较分析。在两种产物中共鉴定出77种挥发性化学成分,其中醇类18种、醛酮类23种、酸类3种、酯类10种、杂环类7种及其他类16种,两种产物中共有成分26种。与MRPs1相比,MRPs2中醛酮、杂环类化合物的相对含量较高,但前者的酯类物质含量更为丰富。(E)-2-辛烯-1-醇、(6Z,9Z)-十五碳二烯-1-醇、苯甲醛、辛醛、6-甲基-5-庚烯-2-酮、2-乙基-3-羟基-4(4H)-吡喃酮、2,3,5-三甲基-6-乙基吡嗪、2-[(甲基二硫基)甲基]呋喃构成了MRPs2的特有成分,γ-丁位十二内酯为MRPs1的特有成分。在两种反应产物中,除4-甲基-5-羟乙基噻唑的相对含量均较高外(MRP1相似文献   

Muscle oxygenation measurement in humans by noninvasive optical spectroscopy and Locally Weighted Regression

We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%.     

Synthesis of New Azocompounds and Fused Pyrazolo[5,1‐c][1,2,4]triazines Using Heterocyclic Components

Diazotization of 3‐methyl‐4‐phenyl‐1H‐pyrazol‐5‐amine 1 in hydrochloric acid has been reported to afford the corresponding diazonium salt 2 . The latter underwent azocoupling with a variety of active methylene compounds (barbituric 3a and thiobarbituric 3b acid, 2‐hetarylpyrimidine‐4,6‐dione 6a , 6b , 4‐hydroxy‐6‐methylpyridin‐2(1H)‐one 10a , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one 10b , 4‐hydroxy‐1‐p‐tolyl‐1H‐pyrazole‐3‐carboxylic acid ethyl ester 14 , 1,3‐thiazolidine‐2,4‐dione 16a , 2‐thioxo‐1,3‐thiazolidin‐4‐one 16b ) to yield new pyrazolylazo derivatives. Fused pyrazolo[5,1‐c][1,2,4]triazines 5 , 9a , 9b , 12 , 13 were obtained by heterocyclization reactions. Copyright © 2013 HeteroCorporation     

顶空液液萃取-气相色谱-质谱法用于白术挥发性成分的分析

采用高温顶空液相萃取再转移的方法,对中药白术中挥发性成分进行萃取分离富集,采用顶空液液萃取/气相色谱-质谱(HS-LP-LPE/GC-MS)联用法进行测定,并与传统水蒸汽蒸馏法(SD)提取的挥发性成分进行对比。对各种测定条件和影响因素进行了考察,最佳萃取条件为:1.0 mL PEG 400为高温萃取剂,样品用量1.2 g,萃取温度120℃,萃取时间60 min,再将萃取剂用1.0 mL正己烷进行反萃取后进行GC-MS分析;采用HS-LP-LPE/GC-MS鉴定了33个组分,占总组分含量93.18%;SD鉴定了31个组分,占总组分含量97.12%。两种方法共同检测到的组分有29个,均以苍术酮(Atractylone)含量最高。结果表明,两种方法所提取的组分基本相同,可用于白术挥发性成分的测定。     

Non‐symmetric bent‐core mesogens with one terminal vinyl group

Two series of non‐symmetric banana‐shaped compounds, both with one alkyl and one alkenyl terminal tail, have been synthesized and studied. Both series were compared with the corresponding series with two saturated terminal alkyl tails. All the compounds have a bent central 1,3‐phenylene bis(4‐benzoyloxy)benzoate core; their mesophases were characterized by polarizing optical microscopy, differential scanning calorimetry, X‐ray diffraction and switching current response experiments. In all four series one of the terminal tails is varied from OC₈H₁₇ to OC₁₆H₃₃. The other terminal tails are OC₁₁H₂₃, O(CH₂)₉CH?=?CH₂, OC₁₀H₂₁ and O(CH₂)₈CH?=?CH₂. The short‐tailed compounds show monotropic or enantiotropic B₁ phases and the long‐tailed compounds the B₂ phase. The introduction of one terminal vinyl group slightly lowers the transition temperatures. The introduction of a second terminal vinyl group further suppresses the liquid crystalline properties. All compounds with B₂ phases have layer spacings that suggest a tilt of ～45° of the bent molecules in the layers, and their switching behaviour is antiferroelectric.     

Ionic liquids as stationary phases in gas chromatography: Determination of chlorobenzenes in soils

The present research focuses on the evaluation of different ionic liquid (IL) stationary phases in gas chromatography. The different IL columns were evaluated in terms of peak resolution (R_s) and peak symmetry for the separation of the chlorobenzenes. The determination of chlorobenzenes in soil samples by means of the optimal IL stationary phase (SLB‐IL82) is proposed as an application. Soil pretreatment was based on a simplified quick, easy, cheap, effective, rugged, and safe extraction procedure and a large injection volume via a programed temperature vaporizer working in solvent vent mode. The retention time of the chlorobenzenes increased as the polarity of the IL column decreased. SLB‐IL82 is the stationary phase that provides the best values as regards R_s and asymmetry factor. Soil sample blanks were spiked with the analytes before subjecting the sample to the extraction process. The existence of a matrix effect was checked and the analytical characteristics of the method were determined in a fortified garden soil sample. The method provided good linearity, good repeatability and reproducibility values, and the LODs were in the 0.1–4.7 μg/kg range. Two fortified soil samples were applied to validate the proposed methodology.     

CT检查参数对腰椎管狭窄症的诊断价值及与疗效、腰椎功能改善的相关性分析

选取我院60例腰椎管狭窄症(LSS)患者作为研究组,同期健康者60例作为对照组,探究CT检查参数对LSS的诊断价值及与疗效、腰椎功能改善的相关性。结果显示,研究组椎管面积、硬膜囊面积、椎管矢径、椎管横径、侧隐窝矢径、侧隐窝角小于对照组(P<0.05);CT各参数联合诊断LSS的AUC值大于任一参数单独诊断;疗效优良患者术后3个月椎管面积、硬膜囊面积、椎管矢径、侧隐窝矢径、侧隐窝角大于治疗前及非优良患者(P<0.05);经偏相关性分析发现,CT检查参数与疗效显著相关(P<0.05)。说明LSS疗效、腰椎功能改善情况与椎管面积、硬膜囊面积、椎管矢径等关系密切,CT检查对指导临床完善手术方案有重要意义。     

Bioactive Components of Salvia and Their Potential Antidiabetic Properties: A Review

The utilization of therapeutic plants is expanding around the globe, coupled with the tremendous expansion of alternative medicine and growing demand in health treatment. Plants are applied in pharmaceuticals to preserve and expand health—physically, mentally and as well as to treat particular health conditions and afflictions. There are more than 600 families of plants identified so far. Among the plants that are often studied for their health benefit include the genus of Salvia in the mint family, Lamiaceae. This review aims to determine the bioactive components of Salvia and their potential as antidiabetic agents. The search was conducted using three databases (PubMed, EMBASE and Scopus), and all relevant articles that are freely available in the English language were extracted within 10 years (2011–2021). Salvia spp. comprises many biologically active components that can be divided into monoterpenes, diterpenes, triterpenes, and phenolic components, but only a few of these have been studied in-depth for their health benefit claims. The most commonly studied bioactive component was salvianolic acids. Interestingly, S. miltiorrhiza is undoubtedly the most widely studied Salvia species in terms of its effectiveness as an antidiabetic agent. In conclusion, we hope that this review stimulates more studies on bioactive components from medicinal plants, not only on their potential as antidiabetic agents but also for other possible health benefits.     

基于临界电子密度的多载波微放电全局阈值分析

多载波微放电即发生在宽带、大功率真空无源微波部件中的二次电子倍增放电现象, 是影响空间和加速器应用中无源微波部件长期可靠性的主要隐患. 多载波微放电全局阈值功率的预测对于工作在真空环境中的微波部件至关重要, 但迄今尚无有效方法进行上述阈值的准确分析. 本文将微放电发生过程中二次电子分布区域等效为等离子体, 通过在理论上建立微波部件的电磁特性和电子密度间的对应关系, 提出了一种基于测试系统可检测水平的多载波微放电全局阈值功率分析方法. 为了能够通过蒙特卡罗优化方法得到全局阈值, 进一步基于电子加速的类半正弦等效, 提出了微放电演化过程中电子数涨落的快速计算方法. 基于以上两种方法得到的针对实际微波部件的全局阈值分析结果与实验结果相符合. 不同于传统基于多载波信号功率分析的经验方法, 本文基于临界电子密度判断依据和电子数涨落快速计算, 为多载波微放电全局阈值的准确预测提供了一种高效的分析方法.