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1.
采用超高效液相色谱-四极杆-静电场轨道阱质谱结合主成分分析、正交偏最小二乘判别分析对46例结直肠腺瘤患者(年龄57.8 ± 10.7岁)和45例健康人(年龄54.4 ± 8.2岁)的血清样本进行分析,通过变量权重投影分析和火山图筛选结直肠腺瘤患者血清中的代谢标志物,利用受试者工作特征曲线(ROC)验证代谢标志物的诊断能力。结果表明,两组血清的代谢轮廓有显著差异,筛选并鉴定了20个生物标志物,涉及缬氨酸、亮氨酸和异亮氨酸合成,花生四烯酸代谢、α-亚麻酸代谢、亚油酸代谢、氨酰-tRNA合成、鞘脂代谢、甘油磷脂代谢、色氨酸代谢,其生物标志物16-羟基棕榈酸、花生四烯酸、肌酸、缬氨酸、亮氨酸、色氨酸、α-亚麻酸、牛磺鹅脱氧胆酸、LysoPC(20∶3)的ROC曲线面积(AUC)均大于0.90,特异性与灵敏度较高,对于结直肠腺瘤筛查具有较高的诊断价值和临床应用潜力。研究结果可为基于代谢组学的结直肠腺瘤筛查提供参考资料。  相似文献   

2.
采用液相色谱-飞行时间质谱联用技术(LC-TOF MS)对高脂血症金黄地鼠的肝匀浆液进行代谢谱 分析,并利用模式识别挖掘潜在生物标志物以探索发病机制。采用反相色谱(RPLC)和亲水作用色谱(HILIC) 两种模式分离肝匀浆液中的内源性代谢产物。采用偏最小二乘法判别分析(PLS-DA)进行数据分析,结合标 准品与数据库比对、二级质谱裂解规律对内源性成分进行定性分析。结果显示,模型组和对照组在RPLC和 HILIC两种分离模式下均有良好的区分。与对照组相比,在高脂血症组的金黄地鼠肝脏中鉴定出16种差异代 谢物,其涉及的主要代谢途径为嘌呤代谢、磷脂酰胆碱代谢、鞘脂代谢和赖氨酸代谢等。这些异常的内源性 成分及其生物代谢途径可为了解高脂血症金黄地鼠肝脏发病机制提供依据。  相似文献   

3.
陈煜  邱智军  张彬 《分析测试学报》2021,40(12):1690-1696
该文利用竞争性自适应加权算法(CARS)筛选重要的人血浆荧光光谱变量,并结合偏最小二乘法判别分析(PLS-LDA)建立了结直肠癌患者与非癌患者的分类模型,同时与全波长模型和基于平行因子分析(PARAFAC)建立的模型进行比较。从模型评价指标看,CARS-PLS-LDA的性能显著优于全波长模型和基于PARAFAC的模型。高波未稀释组和低波稀释组的荧光光谱结合CARS-PLS-LDA分类模型的AUC(Area under curve)值均高于0.9,可有效地识别结直肠癌患者。结果表明,CARS变量筛选能够明显改善结直肠癌分类模型的性能,有助于后续癌症临床诊断工具的开发与研究。  相似文献   

4.
该研究采用超高效液相色谱-四极杆-静电场轨道阱质谱结合主成分分析(PCA)、正交偏最小二乘判别分析(OPLS-DA)对结直肠癌(CRC)患者和健康人的各50例血清样本进行脂质组学分析,通过P < 0.05和倍数变化 > 1.5或 < 0.67筛选组间差异脂质,利用受试者工作特征曲线(ROC)验证其诊断能力,为基于脂质组学的CRC筛查提供参考。结果表明,两组血清脂质谱存在明显差异,发现155种差异脂质,以磷脂酰胆碱(PC)和甘油三酯(TAG)为主,涉及磷脂酰胆碱代谢和甘油三酯代谢。筛选并鉴定9个脂质标志物,包括棕榈酰乙醇胺、棕榈酸、鞘氨醇、鞘磷脂(SM)d40∶3、SM d36∶0、TAG 58∶1、PC 34∶2、PC 36∶6、PC 38∶7,其ROC曲线面积(AUC)均大于0.80,特异性与灵敏度较高,对于CRC筛查具有较高的临床诊断价值和应用潜力。  相似文献   

5.
采用超高效液相色谱-飞行时间质谱联用技术(UPLC-Q/TOF MS)对恩施土家族苗族自治州60例健康志愿者(对照组)和65例痛风患者(痛风组)的血清样本建立代谢图谱,基于主成分分析及正交偏最小二乘判别分析对所得数据进行模式识别,并结合变量权重投影分析及火山图筛选出痛风患者的血清代谢标志物。通过数据分析和数据库检索,共筛选出63种差异代谢物,其中27种代谢物显著上调(P <0.05),36种代谢物显著下调(P <0.05),主要包括甘油磷脂类、氨基酸类及胆碱等成分。首先,对以上差异代谢物进行受试者工作特征曲线(ROC)分析,其中曲线下面积(AUC)大于0.8的14种代谢物是诊断效能较好的代谢物;然后对筛选的63种差异代谢物进行代谢通路富集分析,以Impact> 0.1且P <0.05为标准,得到影响最大的代谢通路主要有甘油磷脂代谢、醚性脂质代谢、亚油酸代谢、半胱氨酸和蛋氨酸代谢、花生四烯酸代谢及戊糖和葡萄醛酸的互相转化等。综上,痛风患者和健康对照人群的血清代谢水平有明显差异,差异代谢物的鉴定为痛风的发病机制和早期筛查提供了实验依据。  相似文献   

6.
结直肠腺瘤(Colorectal adenoma,CA)发展成为结直肠癌(Colorectal cancer,CRC)是一个相对漫长而隐匿的过程,然而,目前仍缺乏微创且可靠的生物标志物来区分CA和CRC患者。该文采用超高效液相色谱-串联高分辨质谱(UHPLC-HRMS)技术结合多元统计分析方法对64例CA患者和84例CRC患者的血清样本进行代谢组学比较分析,结合P <0.05和倍数变化> 1.50或<0.67筛选两者的血清差异代谢物,并通过受试者工作特征曲线(ROC)分析考察其对CA和CRC的鉴别能力。同时利用差异代谢物的通路及富集分析初步探索CA癌变的代谢机制。结果表明,两组的血清代谢谱存在差异,据此筛选并鉴定获得66种组间差异代谢物,主要涉及不饱和脂肪酸的生物合成、嘌呤代谢、亚油酸代谢,提示其可能与CA癌变有关。此外,PC 36∶3、腺嘌呤、鞘氨醇、PC 18∶0、PC 20∶4标志物组合的ROC曲线下面积为0.941,对CA和CRC表现出良好的判别效能,可为CRC的临床早期预防提供有价值的参考。  相似文献   

7.
该研究基于近红外光谱(NIRs)技术,以2016~2018年来自13个省份的937个烟叶样本为研究对象,比较了竞争性自适应重加权采样方法(CARS)、蒙特卡洛无信息变量消除法(MC-UVE)以及随机青蛙算法(RF)3种变量筛选方法的极限学习机(ELM)模型效果,与常规判别方法偏最小二乘判别分析(PLS-DA)比较,验证了ELM模型的优势。并通过教与学优化(TLBO)算法对ELM模型进行优化,建立烤烟样本的等级判定模型。结果表明,验证集的分类正确率达到90.16%,测试集的外部验证表现良好,TLBO-ELM模型收敛速度快,泛化能力强,可应用于烤烟等级判定。近红外光谱技术结合教与学算法优化极限学习机为智能化实现烟叶等级判定提供了一种新方法。  相似文献   

8.
为对比分析产地对丹参中酚酸类和丹参酮类成分的影响,采用超高效液相色谱(UPLC)及超高效液相色谱-三重四极杆质谱联用技术(UPLC-QQQ-MS)同时测定来自山东、河南、陕西、四川、安徽共408份丹参中23种化学成分的含量,并对数据进行多元统计分析。研究发现17种酚酸类及6种丹参酮类成分在不同产地丹参中均存在显著差异。山东的丹参样品中丹参酮类成分含量最高,四川的样品中丹酚酸B含量最高,安徽丹参的紫草酸、丹酚酸Y、丹酚酸A、丹酚酸D和丹酚酸E等的含量最高。多种模式识别方法均可用于不同产地丹参的判别分析,线性判别分析(LDA)为产地溯源的最佳模型。正交偏最小二乘法判别分析(OPLS-DA)表明不同产地丹参的化学成分差异较大,不同来源丹参的质量差异标志物不仅限于丹酚酸B、丹参酮Ⅰ、隐丹参酮、丹参酮ⅡA,其他丹酚酸类及丹参酮类也是重要的质量标志物。该研究对全国不同主产区的栽培丹参进行多指标含量测定及建模分析,所建立的定量方法专属性强、准确高效,可为不同产地丹参的质量控制及产地判别提供参考。  相似文献   

9.
光谱分析技术由于具有简单、快速、无损等优势,在复杂体系的定性和定量分析中得到了广泛应用。然而光谱中往往包含成百上千的波长点,有些波长点与研究的目标性质并不相关,加大了计算量并降低了模型的预测准确度。因此,在建立模型前需要进行变量选择。最小绝对收缩与选择算子(LASSO)可将回归系数收缩为0,进而达到变量选择的目的。该研究将LASSO用于三元调和油样品近红外光谱和生物样品拉曼光谱的变量选择,基于偏最小二乘(PLS)和多元线性回归(MLR)模型,分别对香油和肌氨酸的含量进行定量分析,并与无信息变量消除-PLS(UVE-PLS)、蒙特卡罗结合UVE-PLS(MCUVE-PLS)和随机检验-PLS(RT-PLS)3种变量选择方法进行比较。结果表明,基于LASSO的变量选择方法保留的变量数最少,运算速度最快。对三元调和油样品,LASSO-PLS预测的准确度最高;对生物样品,LASSO-MLR预测的准确度最高。因此,基于LASSO的变量选择算法有望在光谱分析领域中得到良好应用。  相似文献   

10.
毒品的日益泛滥和快速更新对缉毒部门进行现场识别和快速检测带来了巨大挑战,寻求快速、准确、低成本的现场检测方法对毒品的有效管控和案件侦破具有重要意义。该文通过使用手持式近红外光谱仪,结合粒子群优化-极限学习机(PSO-ELM)算法建立了冰毒和海洛因的现场案件快速溯源模型,并与传统的线性判别分析(LDA)算法和支持向量机(SVM)算法进行比较。结果表明:相对于传统的分类模型,该文所建立的PSO-ELM案件溯源模型能获得更好的分类结果和更高的计算效率。该方法能够实现毒品的现场快速溯源,为禁毒实战中的案件侦破提供制毒、贩毒线索。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

17.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

18.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
袁丽秋 《化学教育》2006,27(5):8-10
面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。  相似文献   

20.
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