With the increase in mortality caused by pathogens worldwide and the subsequent serious drug resistance owing to the abuse of antibiotics, there is an urgent need to develop versatile analytical techniques to address this public issue. Vibrational spectroscopy, such as infrared (IR) or Raman spectroscopy, is a rapid, noninvasive, nondestructive, real-time, low-cost, and user-friendly technique that has recently gained considerable attention. In particular, surface-enhanced Raman spectroscopy (SERS) can provide a highly sensitive readout for bio-detection with ultralow or even trace content. Nevertheless, extra attachment cost, nonaqueous acquisition, and low reproducibility require the conventional SERS (C-SERS) to further optimize the conditions. The emergence of dynamic SERS (D-SERS) sheds light on C-SERS because of the dispensable substrate design, superior enhancement and stability of Raman signals, and solvent protection. The powerful sensitivity enables D-SERS to perform only with a portable Raman spectrometer with moderate spatial resolution and precision. Moreover, the assistance of machine learning methods, such as principal component analysis (PCA), further broadens its research depth through data mining of the information within the spectra. Therefore, in this study, D-SERS, a portable Raman spectrometer, and PCA were used to determine the phenotypic variations of fungal cells Candida albicans (C. albicans) under the influence of different antifungals with various mechanisms, and unknown antifungals were predicted using the established PCA model. We hope that the proposed technique will become a promising candidate for finding and screening new drugs in the future.

在大气污染物中有害气体成分众多,运用太赫兹、红外等振动光谱检测所得不同成分的吸收峰较难辨别。设计了一种根据所测光谱中可能包含的物质的理论光谱分析所测光谱中不同物质所占比重的算法。利用实验峰值与不同理论峰值的对应关系构建超定方程组,分别基于遗传算法和模拟退火算法进行求解,得到实验光谱中各物质理论光谱的贡献。为了验证所提算法的准确性,利用该算法对已知水团簇组成的水汽系统的实验光谱进行了分析,结果表明:所提算法能够得到不同成分的比重,具有较强的实用性。

Amyloidopathy is one of the most prominent hallmarks of Alzheimer's disease (AD), the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregationprone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid) protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy.

运用密度泛函理论, 在6-31G(d)基组水平上对甘氨酸直链寡肽进行几何优化, 并对其几何结构、 平均结合能、 振动频率进行计算。 结果表明, 平均结合能随着肽链增加单调变化, 并趋于稳定; 寡肽链键长的分析发现, 链向与径向方向上变化趋势相反, 存在各向异性。 红外光谱的分析发现, 位于肽键上同一基团的伸缩振动与弯曲振动分别发生红移和蓝移, 并存在各向异性。 这些现象源于: 准一维的纳米结构导致了键长的各向异性; 相同基团之间的诱导效应、 耦合效应及氢键等因素导致了振动频率的红移和蓝移等现象。 我们得出结论: 甘氨酸直链寡肽链的生长利于结构的稳定性, 在能量上, 推测出寡肽链有自组装生长的趋势; 在寡肽链的生长过程中, 通过构象和光谱的现象, 推断其物理化学属性存在尺寸效应。 肽链端部基团的物理化学属性非常稳定, 基本不受寡肽链长度的影响。 该结果对应用红外光谱测量寡肽链的残基数及长度、 特殊功能寡肽链的制备等工作具有指导意义。

采用红外傅里叶变换光谱仪测量了异戊二烯与羟基反应产物的红外光谱,并结合量子化 学理论密度泛函方法对异戊二烯与羟基自由基的反应机理进行了理论研究。使用密度泛 函B3LYP/6-31G(d,p)方法计算了异戊二烯羟基加成反应中每个反应物和产物的频率, 实验与理论结果符合的很好。研究发现了破坏羟基进攻异戊二烯的反应通道,并从 机理上探讨了阻断该关键反应通道的方法。

联合FTIR, FT-拉曼表征了乐果的振动光谱, 获得了固态及不同酸碱条件下饱和液态乐果的振动特征信息; 以金/银核-壳复合粒子为基底, 获得了乐果在酸碱条件下一系列浓度的表面增强拉曼散射(SERS)光谱, 考察了乐果分子在该基底表面的吸附状态及其酸碱影响, 推测了乐果与金/银核-壳复合粒子作用机理; 结果表明: νas(NH), νas(CH3), ν(OCN), τ(OCN), ν(P—O), ν(PS), ν(C—C), δ(P—O—C)为乐果分子特征振动; 酸、 碱条件下, 在1.0×10-3 mol·L-1为乐果与基底作用的最佳浓度; 乐果主要以P—O—C, OCC, (S—CH2), PS, CH3与金/银核-壳复合粒子基底相作用, 探讨了酸碱条件下磷酸酯键不同离解历程对吸附的影响. 为研究有机磷农药的形态变化提供有益参考.

利用红外和拉曼光谱研究了不同浓度下高氯酸锂在N,N-二甲基甲酰胺、 乙腈、 四氢呋喃、 丙酮、 二甲亚砜、 乙酸甲酯等有机溶剂中的缔合情况, 分析了高氯酸根ν1谱带的变化, 指认了溶液中光谱自由离子、 直接接触离子对和离子对二聚体。 使用量子化学方法计算了不同结构直接接触离子对和离子对二聚体的稳定构型和光谱行为, 并和实验值进行了比较, 考察了溶剂化模型、 溶剂分子对直接接触离子对或离子对二聚体结构的影响, 探讨了量子化学方法指认离子对的可能性和正确性。

采集三峡库区(TGRA)沿岸6个典型段面沉积物及水淹线上土壤样品, 分别提取腐殖质, 分离并纯化腐殖酸和富里酸, 联合红外和拉曼的分子振动光谱技术, 表征了各段面腐殖酸和富里酸的分子结构, 归属了各振动峰位, 获得了库区土壤及沉积物中腐殖质分子的官能团特征振动信息; 结合库区土壤腐殖化程度、 土壤背景、 利用方式、 水位涨落等环境条件, 考察了腐殖质官能团振动特征变化。 结果显示: 各采样段面的腐殖质结构中均以C—O, C—C, 及聚合氢键的振动特征较显著, 上游土壤腐殖质结构中的官能团数量多于下游土壤; 土壤的腐殖化程度对其腐殖质结构的振动光谱影响较大; 农耕模式的土壤表现出较高的腐殖化程度; 沉积物与本底土壤腐殖质结构的振动特征变化不明显。

用量子化学从头算法计算了苯、吡啶及吡嗪分子的超拉曼和表面增强的超拉曼光谱,并比较了理论计算与实验测量的结果. 用Gaussian98中的密度泛函的方法计算分子的偶极矩、极化率和超极化率以及偶极矩、极化率的导数,而超极化率的导数则有限差分的方法来计算. 为了检验有限差分法的准确性,用该方法计算了上述分子的红外和拉曼光谱,其结果与Gaussian98的计算结果高度一致. 建立了基于有限差分法计算分子红外、拉曼、表面增?坷? 超拉曼和表面增强超拉曼的光谱强度的方法,并编写了计算程序.