建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质...建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。展开更多
为满足不同种类食品对大豆分离蛋白(soybean protein isolate,SPI)不同功能性的需求,本研究利用红外光谱快速采集70组不同pH值处理后SPI的数据,探讨pH值变化对SPI结构含量的影响。使用均值中心化、多元散射校正、标准正态变量变换和归...为满足不同种类食品对大豆分离蛋白(soybean protein isolate,SPI)不同功能性的需求,本研究利用红外光谱快速采集70组不同pH值处理后SPI的数据,探讨pH值变化对SPI结构含量的影响。使用均值中心化、多元散射校正、标准正态变量变换和归一化算法对红外光谱数据进行预处理,基于二维相关红外光谱提取特征波段,再利用偏最小二乘(partial least square,PLS)法和算术优化算法-随机森林(arithmetic optimization algorithm-random forests,AOA-RF)建立不同pH值条件下SPI结构及含量的预测模型。结果表明,经均值中心化和多元散射校正结合处理后,α-螺旋、β-折叠、β-转角和无规卷曲模型的相对标准偏差分别为1.29%、1.60%、1.37%、7.28%,两者结合对光谱数据的预处理效果最佳。预测α-螺旋和β-折叠含量最优模型为AOA-RF(特征波段),校正集决定系数为0.9350和0.9266,预测集决定系数为0.8568和0.8701;预测β-转角和无规卷曲含量最优模型为PLS(特征波段),校正集决定系数为0.9154和0.8817,预测集决定系数为0.8913和0.7843。本研究结果可为工业生产过程中产品质量快速检测和工艺条件控制提供理论支撑。展开更多
A 23-year-old male presented with a three-week-history of crampy abdominal pain and melaena.Colonoscopy revealed a friable mass filling the entire lumen of the cecum;histologically,it was classified as perivascular ep...A 23-year-old male presented with a three-week-history of crampy abdominal pain and melaena.Colonoscopy revealed a friable mass filling the entire lumen of the cecum;histologically,it was classified as perivascular epithelioid cell tumor(PEComa).An magnetic resonance imaging scan showed,in addition to the primary tumor,two large mesenteric lymph node metastases and four metastatic lesions in the liver.The patient underwent right hemicolectomy and left hemihepatectomy combined with wedge resections of metastases in the right lobe of the liver,the resection status was R0.Subsequently,the patient was treated with sirolimus.After 4 mo of adjuvant mammalian target of rapamycin inhibition he developed two new liver metastases and a local pelvic recurrence.The visible tumor formations were again excised surgically,this time the resection status was R2 with regard to the pelvic recurrence.The patient was treated with 12 cycles of doxorubicin and ifosfamide under which the disease was stable for 9 mo.The clinical course was then determined by rapid tumor growth in the pelvic cavity.Second line chemotherapy with gemcitabine and docetaxel was ineffective,and the patient died 23 mo after the onset of disease.This case report adds evidence that,in malignant PEComa,the mainstay of treatment is curative surgery.If not achievable,the effects of adjuvant or palliative chemotherapy are unpredictable.展开更多
文摘为满足不同种类食品对大豆分离蛋白(soybean protein isolate,SPI)不同功能性的需求,本研究利用红外光谱快速采集70组不同pH值处理后SPI的数据,探讨pH值变化对SPI结构含量的影响。使用均值中心化、多元散射校正、标准正态变量变换和归一化算法对红外光谱数据进行预处理,基于二维相关红外光谱提取特征波段,再利用偏最小二乘(partial least square,PLS)法和算术优化算法-随机森林(arithmetic optimization algorithm-random forests,AOA-RF)建立不同pH值条件下SPI结构及含量的预测模型。结果表明,经均值中心化和多元散射校正结合处理后,α-螺旋、β-折叠、β-转角和无规卷曲模型的相对标准偏差分别为1.29%、1.60%、1.37%、7.28%,两者结合对光谱数据的预处理效果最佳。预测α-螺旋和β-折叠含量最优模型为AOA-RF(特征波段),校正集决定系数为0.9350和0.9266,预测集决定系数为0.8568和0.8701;预测β-转角和无规卷曲含量最优模型为PLS(特征波段),校正集决定系数为0.9154和0.8817,预测集决定系数为0.8913和0.7843。本研究结果可为工业生产过程中产品质量快速检测和工艺条件控制提供理论支撑。
文摘A 23-year-old male presented with a three-week-history of crampy abdominal pain and melaena.Colonoscopy revealed a friable mass filling the entire lumen of the cecum;histologically,it was classified as perivascular epithelioid cell tumor(PEComa).An magnetic resonance imaging scan showed,in addition to the primary tumor,two large mesenteric lymph node metastases and four metastatic lesions in the liver.The patient underwent right hemicolectomy and left hemihepatectomy combined with wedge resections of metastases in the right lobe of the liver,the resection status was R0.Subsequently,the patient was treated with sirolimus.After 4 mo of adjuvant mammalian target of rapamycin inhibition he developed two new liver metastases and a local pelvic recurrence.The visible tumor formations were again excised surgically,this time the resection status was R2 with regard to the pelvic recurrence.The patient was treated with 12 cycles of doxorubicin and ifosfamide under which the disease was stable for 9 mo.The clinical course was then determined by rapid tumor growth in the pelvic cavity.Second line chemotherapy with gemcitabine and docetaxel was ineffective,and the patient died 23 mo after the onset of disease.This case report adds evidence that,in malignant PEComa,the mainstay of treatment is curative surgery.If not achievable,the effects of adjuvant or palliative chemotherapy are unpredictable.
