基于红外光谱的鲜地黄、生地黄和熟地黄成分差异分析

运用傅里叶变换衰减全反射红外光谱(ATR-FTIR)对鲜地黄水提物、生地黄水煎液和熟地黄水煎液的整体成分进行差异分析,并运用离子色谱法对差异成分进行定量分析,研究鲜地黄与其炮制品的整体成分及变化规律。ATR-FTIR中,三种地黄在糖区有差异,其中鲜地黄糖区特征峰在1 140, 1 047和1 000 cm^-1,生地黄糖区特征峰为1 140和1 045 cm^-1,熟地黄糖区特征峰为1 142和1 029 cm^-1,且三种地黄峰形状不同。二阶导数红外光谱(SDIR)进一步发现,地黄炮制过程中糖类成分在1 200～600 cm^-1之间的特征峰变化最为显著。三种地黄提取液的特征峰位置相近,但相对峰强度不同,且随着炮制过程呈规律性变化。可以推测出在鲜地黄炮制过程中,鲜地黄中多糖发生水解,变成熟地黄中的寡糖或者单糖。应用离子色谱法对8种单糖和寡糖进行定量分析,所建立方法线性关系良好(R²≥0.999 0)。定量结果显示,葡萄糖、蜜二糖、半乳糖、甘露糖、甘露三糖、水苏糖和毛蕊花糖苷在鲜地黄、...     

Preparation of Cellulose Nanocrystals from Jujube Cores by Fractional Purification

Jujube cores are fiber-rich industrial waste. Dewaxing, alkali treatment, bleaching, and sulfuric acid hydrolysis were used to generate cellulose nanocrystals (CNCs) from the jujube cores in this study. The morphological, structural, crystallinity, and thermal properties of the fibers were investigated using FE-SEM, TEM, AFM, FT-IR, XRD, and TGA under various processes. CNCs’ zeta (ζ) potential and water contact angle (WAC) were also investigated. The findings demonstrate that non-fibrous components were effectively removed, and the fiber particles shrunk over time because of many activities. CNCs had a rod-like shape, with a length of 205.7 ± 52.4 nm and a 20.5 aspect ratio. The crystal structure of cellulose Iβ was preserved by the CNCs, and the crystallinity was 72.36%. The temperature of the fibers’ thermal degradation lowered during the operations, although CNCs still had outstanding thermal stability (>200 °C). Aside from the CNCs, the aqueous suspension of CNCs was slightly agglomerated; thus, the zeta (ζ) potential of the CNCs’ suspension was −23.72 ± 1.7 mV, and the powder had high hydrophilicity. This research will be valuable to individuals who want to explore the possibility for CNCs made of jujube cores.     

南疆红枣品质近红外光谱在线模型参数的实验研究

为建立南疆红枣品质近红外光谱在线校正模型,分析了在线检测结果的主要影响因素,对相应的参数进行了实验研究。设置红枣不同的光谱采集条件,如测量状态、波段谱区、仪器参数等,利用近红外光谱仪和自行设计的红枣批量采集附件,获取南疆红枣品质光谱,通过光谱预处理和检测精度相结合的办法选择条件参数。通过不同建模参数进行PLS光谱校正和二维相关光谱分析,选择糖度特征光谱参数。结果表明:红枣糖度中心波长9 116,9 418和10 500cm-1,采集分辨率16cm-1,扫描次数8次,糖度相对误差8%～10%,单粒红枣光谱数据量减少为原来的1/10,采集时间减少了3s左右。通过实验参数,压缩了数据量,建立了初级在线校正模型,基本实现南疆红枣品质近红外光谱在线检测。     

估测作物冠层生物量的新植被指数的研究

冠层鲜生物量是指示作物长势状况的重要指标,可用于诊断作物氮素营养状况。但常规测定生物量的方法需要破坏性取样,不利于帮助精准施肥管理决策。遥感技术作为快速分析手段可用于估测作物多种生理、生化参数,特别是借助植被指数。研究表明归一化差值植被指数(normalized difference vegetationindex,NDVI)、最优土壤调节指数(optimization of soil-adjusted vegetation index,OSAVI)等现已构建植被指数可用于准确估测中低生物量信息,但在较高冠层生物量条件下,它们的估测能力显著下降。文章旨在提出更通用的新植被指数用于估测冠层生物量,以提高遥感技术在较高生物量条件下的预测准确度。试验在加拿大魁北克省的St-Jean-sur-Richelieu地区进行,5年(2004~2008)试验中采集了玉米及小麦不同生育期的地面高光谱数据及对应生物量信息,并在2005年获取航空机载高光谱影像一景(compact airborne spectro-graphic imager,CASI)。研究提出了红边三角植被指数(red-edge triangular vegetation index,RTVI),并将其与一些常见植被指数进行比较分析。结果表明RTVI是最好的估测冠层生物量的指数,在较高生物量条件下仍保持其对生物量变化的高敏感性,其与生物量间的决定系数为0.96。基于CASI影像,RTVI预测生物量值与实际测定值间的决定系数(R2)为0.58,预测标准误差为0.44 kg.m-2,取得了较好的结果。     

鲜人参中2种丙二酰基人参皂苷的分离鉴定

采用硅胶柱层析方法,流动相分别为氯仿-甲醇-水(65∶35∶10,V/V)、氯仿-甲醇-水(6∶4∶1)和正丁醇-乙酸乙脂-甲醇-水(4∶2∶1∶1)和高效液相(Nuc leosil C18(250 mm×10 mm,5μm)色谱柱;流动相为己腈-水(75∶25);流速为3.0 mL/m in;柱温30℃;检测波长203 nm。从中国鲜人参中分离得到丙二酰基人参皂苷R c和丙二酰基人参皂苷Rb2,并通过其理化性质、红外光谱、质谱和核磁共振谱对化合物的结构进行了鉴定,证明其结构分别为3-O-[6-O-丙二单酰-β-D-葡萄吡喃糖(1→2)-β-D-葡萄吡喃糖]-20-O-[α-L-阿拉伯呋喃糖(1→6)-β-D-葡萄吡喃糖]-20(S)-原人参二醇和3-O-[6-O-丙二单酰-β-D-葡萄吡喃糖(1→2)-β-D-葡萄吡喃糖]-20-O-[α-L-阿拉伯吡喃糖(1→6)-β-D-葡萄吡喃糖]-20(S)-原人参二醇;丙二酰基人参皂苷R c为首次从中国鲜人参中分得。     

高光谱结合二维相关光谱检测灵武长枣中半纤维素的含量

利用高光谱成像技术与二维相关光谱（2D-COS）结合化学计量学检测灵武长枣半纤维素含量。采用定量瘀伤装置获得0,Ⅰ,Ⅱ,Ⅲ,Ⅳ级瘀伤长枣模型,通过高光谱和分光光度计分别获得样品高光谱图像和半纤维素含量。蒙特卡洛异常值检测法剔除异常样本后,分别用随机划分法（RS）,Kennard-Stone法（KS）、光谱-理化值共生距离法（SPXY）和3∶1比例法对样本集划分校正预测。采用基线校准（Baseline）、去趋势（De-trending）和标准化（Normalize）对长枣原始光谱预处理后建立偏最小二乘回归模型（PLSR）,优选最佳样本集划分及预处理方法。利用2D-COS将光谱信号扩展到第2维,在全光谱范围内寻找与半纤维素含量相关的敏感波段区间。采用竞争性自适应加权算法（CARS）、引导软收缩（BOSS）、区间变量迭代空间收缩方法（iVISSA）、变量组合集群分析法（VCPA）以及iVISSA+BOSS,iVISSA+CARS和iVISSA+VCPA方法在2D-COS敏感波段区间进行特征波长提取,并建立基于特征波长的PLSR模型。结果表明,样本集经3∶1划分和Baseline预处理后建立的基于全波段的PLSR模型最优,故最佳样本集划分方法为3∶1,预处理方法为Baseline,用于后续特征波长提取。通过2D-COS分析发现3个与半纤维素相关的自相关峰（401,641和752 nm）;在2D-COS敏感区域（401～752 nm范围内）,采用BOSS,CARS,iVISSA,VCPA,iVISS+BOSS,iVISS+CARS,iVISS+VCPA分别提取了14,26,39,12,15,22和11个对应的特征波长,占总波长的18.9%,35.1%,52.7%,16.2%,20.2%,29.7%和14.8%。对比2D-COS和特征波建立的PLSR模型,2D-COS+iVISSA-PLSR模型效果较好,其R2_C=0.747 9,R2_P=0.604 7,RMSEC=0.043 8,RMSEP=0.060 3。研究表明,利用高光谱成像技术结合2D-COS可实现灵武长枣半纤维素含量的快速检测。     

Admicelle-mediated collection followed by flotation for the preconcentration of trace metals in fresh waters

Dithizone-impregnated admicelles were prepared by mixing silica particles with dithizone and cetyltrimethylammonium chloride in 0.1 mol L⁻¹ aqueous ammonia. The resulting admicelles were added to 1000 mL of sample solution and dispersed by stirring for 15 min. Traces of Ni(II), Cu(II), Ga(III), Cd(II), Pb(II) and Bi(III) in the solution were simultaneously incorporated into the admicelles at pH 7.5-9. With the aid of a rising stream of numerous tiny bubbles, the admicelles were floated on the solution surface and collected in a small sampling vessel by suction. The metals were desorbed from the admicelles with dilute nitric acid and determined by inductively coupled plasma-mass spectrometry. The proposed method offered a 100-fold multielement preconcentration and it was applicable to the analysis of river and pond waters.     

Competitive food supply chain networks with application to fresh produce

In this paper, we develop a network-based food supply chain model under oligopolistic competition and perishability, with a focus on fresh produce. The model incorporates food deterioration through the introduction of arc multipliers, with the inclusion of the discarding costs associated with the disposal of the spoiled food products. We allow for product differentiation due to product freshness and food safety concerns, as well as the evaluation of alternative technologies associated with various supply chain activities. We then propose an algorithm with elegant features for computation. A case study focused on the cantaloupe market is investigated within this modeling and computational framework, in which we analyze different scenarios prior/during/after a foodborne disease outbreak.     

Simultaneous determination of metal ions as complexes of pentamethylene dithiocarbamate in Indus river water,Pakistan

River water samples before and after mixing with industrial effluents were collected at an interval of 4 weeks for one year and analyzed for simultaneous determination of Fe³⁺, Cr³⁺, Mn²⁺, Cu²⁺, Ni²⁺and Co²⁺ after preconcentration using pentamethylene dithiocarbamate (PMDTC) as derivatizing reagent and subsequent solvent extraction by high performance liquid chromatography (HPLC). The average levels (n = 12) of metal ions were found in the range of 14.2–542 μg/L. The results were then compared with a standard flame atomic absorption spectrophotometric method revealed no significant differences.     

红枣中4种链格孢菌毒素的检测及风险评估

建立了超高效液相色谱-三重四极杆质谱(UPLC-MS/MS)快速检测红枣中链格孢菌代谢产生的细交链格孢菌酮酸(TEA)、链格孢酚(AOH)、交链格孢酚单甲醚(AME)和腾毒素(TEN) 4种链格孢菌毒素的方法。采用2. 0%甲酸-乙腈溶液超声提取,辅以0. 2 g Na Cl盐析,使用BEH C18色谱柱在6 min内快速分离毒素,并采用多反应监测模式(MRM)检测红枣中的4种链格孢菌毒素。除了链格孢酚的线性范围为1. 0～100μg/L外,其他3种毒素的线性范围均为10～1 000μg/L,线性关系(r2)均大于0. 990,检出限为0. 5～12. 4μg/kg。4种毒素在空白基质中的加标回收率为92. 8%～116%,相对标准偏差为0. 5%～11. 2%,可满足红枣中链格孢菌毒素的检测要求。运用毒理学软件理论计算得到成年人对4种毒素的允许每日暴露量(PDE)为19. 30～25. 65μg/d。