基于近红外光谱技术的白茶可溶性糖总量快速测定研究

本文以积分球漫反射模块采集113份不同等级不同年份的白茶近红外光谱图并进行预处理分析,采用蒽酮比色法对来自不同厂家的白茶进行含量测定,运用偏最小二乘法(PLS)建立了白茶可溶性糖总量快速测定模型并对模型进行验证。试验结果表明所建立模型的相关系数(R)为0. 963,校正均方根差(RMSEC)为0. 363 9,验证均方根差(RMSEP)为0. 349,验证集平均相对误差为3. 11%。通过NIRS快速测定白茶总糖含量具有较高的可行性,该方法预测结果较好,能够准确、快速、无损的对白茶可溶性糖总量进行快速定量分析。     

植食性金龟子信息化学物质的研究

金龟子信息化学物质包括性信息素、聚集信息素和植物源引诱剂。目前已鉴定出的性信息素大多集中于丽金龟科和鳃金龟科,犀金龟科只鉴定出了几种聚集信息素,有关植物源引诱剂方面的研究则集中于丽金龟科和花金龟科。本文总结了金龟子信息化学物质的化学结构特点,并评述了金龟子化学通讯中独特的手性性信息素相互拮抗作用及性信息素生物合成的研究。     

近红外光谱技术在医学上应用进展

本文介绍了近红外光谱分析技术在医学领域的应用情况,并对该技术未来发展方向及其局限性进行了分析。     

对应分析在近红外有效波长选择的应用

针对分立波长型近红外判别仪器开发过程中遇到的组合波长优选问题,提出一种基于对应分析的有效波长选择方法.对11种蘑菇样品及其在701-2500nm的光谱信息作对应分析,在对应图上计算各样品点与波长点的距离后,首先由各样品点的最近距离波长点确定出最稳健波长组合,在此基础上,对各样品点的前10、50、200个最近距离波长点进行优选,得出用921nm、1376nm、1424nm、1720nm、2233nm、2454nm这6个波长建立的SVM模型,能在输入变量最少的情况下达到用最稳健波长组合所建模型的预测能力.     

雌雄蚕蛹近红外反射光谱的差异及其模式识别

采用6250型近红外光谱分析仪,从波长6印到1 235nm分别对日系蚕蛹217颗、中系蚕蛹174颗、杂交种蚕蛹330颗做了扫描测试,结果表明：雌雄蚕蛹的近红外光谱有极显著的差异。从日系217颗蚕蛹中随机选取雌雄各50颗作为学习样本,采用逐步判别方法从其二阶导数光谱中抽取5个特征波长作为观测向量,利用二次型判别函数对其余621颗蚕蛹的性别进行识别,其准确率达98.7%。该方法明显优于以蚕蛹重量或大小识别蚕蛹雌雄的方法。     

近红外光谱技术在烟草行业中的应用进展

介绍了近红外光谱分析技术在烟草常规化学成分分析、烟气分析、卷烟配方设计、不同产地模式识别和真假烟鉴别等方面的应用,认为近红外光谱分析技术在烟草行业中正扮演着越来越重要的角色,而且具有十分广阔的应用前景.     

人血清中胆固醇近红外光谱快速检测初步研究

以全自动生化分析仪测定结果为参考值,采用傅利叶变换近红外透射光谱技术,结合偏最小二乘法,建立人血清中胆固醇和甘油三酯的定标模型。利用内部交叉验证和自动优化功能对预测模型进行了优化,确定了最优建模参数。模型对人血清中胆固醇和甘油三酯定标样品集的预测值与参考值的相关系数r分别为0．9011、0．9593,预测校正标准误RMSECV分别为15．0mg／dL,21．6mg／dL。表明利用近红外光谱分析技术实现血清中胆固醇和甘油三酯快速检测是可行的。     

基于拉曼光谱的鼻咽癌细胞株总蛋白放射敏感性研究

本文以鼻咽癌细胞株CNE2为放射敏感性的研究对象,经不同剂量X射线照射及不同时间培养后分别提取总蛋白,用共聚焦显微拉曼光谱仪检测其拉曼光谱。统计分析表明:被测样品的拉曼光谱中观察到一些可以归属于蛋白质物质的较为明显的基团频率振动峰;不同剂量的X射线照射后,总蛋白质的平均拉曼光谱与对照组谱形基本一致,但与对照组间的光谱存在着对应峰信号强度的不同。实验提示:照射后谱峰强度的增大或减小,提示着相关物质含量有所改变。分析照射后癌细胞总蛋白拉曼光谱的变化情况,结合数学统计方法,以探寻放射敏感性的特征拉曼标志,可以作为研究肿瘤放射敏感性的手段之一。     

基于支持向量机的皮肤自体荧光光谱分类方法在糖尿病筛查中的应用

将63例II型糖尿病患者以及140例正常人皮肤的自体荧光光谱分为训练集和测试集两类,针对常用的四种核函数,运用交叉验证、网格寻优法计算最优分类参数,然后结合训练集建模并对测试集分类,结果显示使用径向基核函数时分类效果相对最佳。在此基础上,构建了一种基于线性核函数与径向基核函数的混合核函数,该核函数对人体皮肤自体荧光光谱的分类效果较之于径向基核函数更优,其分类正确率为82．61％,敏感性为69．57％,特异性为95．65％。研究结果表明支持向量机可用于人体皮肤自体荧光光谱的分类,有助于提高糖尿病筛查的正确率。     

蚕茧近红外反射（NIR）光谱的模式识别──Ⅰ．对雌雄鲜茧、死笼茧的非破坏性识别

探讨了利用蚕茧近红外反向光谱识别雌雄茧、死笼茧的方法及可行性。采用６２５０型近红外光谱分析仪,从波长６８０ｎｍ到１２３５ｎｍ对２０５颗鲜茧做了非破坏性扫描测试,用逐步判别方法从一、二阶导数光谱数据中抽取特征向量,以此特征向量建立Ｂａｙｅｓ差别函数,对３７５个检验样本进行识别,其符合率达９５．７％,该方法明显优于以茧的重和大小差别雌雄的方法。实验结果还表明,雌雄茧近红外反射光谱的差别,主要是由于蚕肾     

Predicting the cold hardiness of willow stems using visible and near-infrared spectra and sugar concentrations

Closely related, fast-growing clones of willows from northern/continental and southern/maritime origins were assessed for their levels of cold hardiness. Assessments were made during active growth and, subsequently, during cold hardening at mean temperatures of 3°C (the COLD regime) and 8°C (the MILD regime). The onset of hardening was triggered simultaneously in all clones by administering a drastic day length reduction on the first day. The northern/continental clones showed consistently higher rates of hardening than the southern/maritime ones. This was particularly true under the COLD regime, suggesting that their hardening was less sensitive to low temperatures. The stems' visible and near-infrared absorption spectra, and concentrations of ten major soluble sugars, were also determined. Multivariate analysis revealed that spectral data could predict up to 96% of the variation in cold hardiness, when the analysis was restricted to the MILD regime and the data corrected for irrelevant systematic information. Possible direct links between spectral changes and chemical changes are discussed. Multivariate analysis also revealed that sugar concentrations could be used to predict up to 73% of the variation in cold hardiness. Different sugars displayed different patterns of variation during hardening. Concentrations of mannose and myo-inositol both decreased, whereas concentrations of galactose, sucrose, maltose, raffinose and stachyose all increased, but at different times. Dry matter increased markedly during hardening, so expressing the concentrations of sugars relative to dry matter does not provide an accurate measure of the amounts present.     

Time dependence of near-infrared spectra of photodissociated hemoglobin and myoglobin

The near-infrared charge-transfer transitions at approximately 760 nm in photodissociated hemoglobin and myoglobin display very different time dependences. In photodissociated myoglobin at room temperature the transition has fully relaxed to its deoxymyoglobin value by 10 ns. In photodissociated hemoglobin, the transition is shifted by 6 nm to longer wavelengths at 10 ns. It relaxes about halfway back to the deoxyhemoglobin value by about 100 ns but subsequently changes very slowly out to about 100 microseconds when the signal intensity becomes too small to follow any further. The intensity of this transition, present in only five-coordinate hemes, is found to follow the same time dependence as the wavelength change. Consequently, there appears to be a correlation between a structural property of the heme (as inferred from the wavelength of the charge-transfer transition) and a functional property (the CO recombination) of the protein (as inferred from the intensity of the transition). Possible origins for this correlation are considered.     

Identification of glycine spin systems in 1H NMR spectra of proteins using multiple quantum coherences

Double-quantum filtered COSY and triple-quantum filtered COSY techniques have been compared for the tripeptide Gly-Tyr-Gly and for human lysozyme. The insertion of a triple-quantum filter in the COSY experiment leads to dramatic spectral simplification in the fingerprint region of the spectrum and permits the specific identification of glycine spin systems in the complex 1H NMR spectra of proteins. The assignment of these peaks to glycine H alpha can be confirmed using 2D double-quantum correlated spectroscopy.     

Arthritis imaging using a near-infrared fluorescence folate-targeted probe

A recently developed near-infrared fluorescence-labeled folate probe (NIR2-folate) was tested for in vivo imaging of arthritis using a lipopolysaccharide intra-articular injection model and a KRN transgenic mice serum induction mouse model. In the lipopolysaccharide injection model, the fluorescence signal intensity of NIR2-folate (n = 12) and of free NIR2 (n = 5) was compared between lipopolysaccharide-treated and control joints. The fluorescence signal intensity of the NIR2-folate probe at the inflammatory joints was found to be significantly higher than the control normal joints (up to 2.3-fold, P < 0.001). The NIR2-free dye injection group showed a persistent lower enhancement ratio than the NIR2-folate probe injection group. Excessive folic acid was also given to demonstrate a competitive effect with the NIR2-folate. In the KRN serum transfer model (n = 4), NIR2-folate was applied at different time points after serum transfer, and the inflamed joints could be detected as early as 30 hours after arthritogenic antibody transfer (1.8-fold increase in signal intensity). Fluorescence microscopy, histology, and immunohistochemistry validated the optical imaging results. We conclude that in vivo arthritis detection was feasible using a folate-targeted near-infrared fluorescence probe. This receptor-targeted imaging method may facilitate improved arthritis diagnosis and early assessment of the disease progress by providing an in vivo characterization of active macrophage status in inflammatory joint diseases.     

Sex separation of tsetse fly pupae using near-infrared spectroscopy

Implementation of the sterile insect technique for tsetse (Glossina spp.) requires that only sterile male insects be released; thus, at some stage of the fly production process the females have to be removed. A further constraint in the use of the sterile insect technique for tsetse is that the females are needed for colony production and hence, a non-destructive method of sex separation is required. In most tsetse sterile insect technique programmes thus far, females have been eliminated from the released material by hand-separation of chilled adults. Using near-infrared (NIR) spectroscopy, significant differences have been found between the spectra for the pupae of male and female G. pallidipes Austen. Significantly, the differences appear to be maximized 4-5 days before emergence of the adults. Tsetse fly pupae up to five days before emergence can be sexed with accuracies that generally range from 80 to 100%. This system, when refined, will enable effective separation of male and female pupae to be carried out, with emerged females being returned to the colony and males being irradiated and released. If separation can be achieved five days before emergence, this will also enable irradiated male pupae to be shipped to other destinations as required. Other Diptera were evaluated using this system but had lower classification accuracies of 50-74%. This may be due to the difference in reproductive physiology between these different fly groups.     

基于傅里叶变换近红外光谱实时分析1,3-丙二醇发酵过程生物量的在线监测方法

生物量是反映生物发酵过程进展的重要参数,对生物量进行实时监测可用于对发酵过程的调控优化。为克服目前主要采用的离线方法检测生物量时间滞后和人工测量误差较大等缺点,本研究针对1,3-丙二醇发酵过程设计了一个基于傅里叶变换近红外光谱实时分析技术的生物量在线监测实验平台,通过对实时采集光谱预处理以及敏感光谱段分析,应用偏最小二乘算法,建立了1,3-丙二醇发酵过程生物量变化的动态预测模型。以底物甘油浓度为60 g/L和40 g/L的发酵过程作为外部验证实验,分析得到模型的预测均方根误差分别为0.341 6和0.274 3,结果表明所建立的模型具有较好的实时预测能力,能够实现对1,3-丙二醇发酵过程中生物量的有效在线监测。     

Age-grading the biting midge Culicoides sonorensis using near-infrared spectroscopy

Age-grading of insects is important in the control and monitoring of both insect populations and vector-borne diseases. Microscopy and morphological techniques exist to age-grade most blood-feeding flies, but these techniques are laborious, often destructive to the insects, and slow. Near-infrared spectroscopy (NIRS) can be automated and is a non-destructive technique for age-grading. We applied NIRS techniques to age-grade females of the biting midge, Culicoides sonorensis Wirth & Jones (Diptera: Ceratopogonidae), the vector of bluetongue and other arboviruses in North America. Female flies of five known age cohorts (1, 3, 6, 9 and 12 days post-emergence) from three laboratory colonies were used. The data indicate that NIRS can be used to differentiate age groups of C. sonorensis .     

Landscape genetics indicate recently increased habitat fragmentation in African forest‐associated chafers

Today, indigenous forests cover less than 0.6% of South Africa's land surface and are highly fragmented. Most forest relicts are very small and typically occur in fire‐protected gorges along the eastern Great Escarpment. Yet, they hold a unique and valuable fauna with high endemism and ancient phylogenetic lineages, fostered by long‐term climatic stability and complex microclimates. Despite numerous studies on southern African vegetation cover, the current state of knowledge about the natural extension of indigenous forests is rather fragmentary. We use an integrated approach of population‐level phylogeography and climatic niche modeling of forest‐associated chafer species to assess connectivity and extent of forest habitats since the last glacial maximum. Current and past species distribution models ascertained potential fluctuations of forest distribution and supported a much wider potential current extension of forests based on climatic data. Considerable genetic admixture of mitochondrial and nuclear DNA among many populations and an increase in mean population mutation rate in Extended Bayesian Skyline Plots of all species indicated more extended or better connected forests in the recent past (<5 kya). Genetic isolation of certain populations, as revealed by population differentiation statistics (), as well as landscape connectivity statistics and habitat succession scenarios suggests considerable loss of habitat connectivity. As major anthropogenic influence is likely, conservational actions need to be considered.     

Differentiating tobacco budworm and corn earworm using near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) was used to develop a simple and quick technique to differentiate two economically important species, the tobacco budworm, Heliothis cirescens (F.), and corn earworm, Helicoverpa zea (Boddie), which are major pests of cotton, Gossypium hirsutum L., in the southern United States. In practice, it is difficult to distinguish the two species during their immature stages using morphological characteristics unless expensive microscopy equipment or trained technicians are available. The current studies demonstrated that the two species could be quickly and readily differentiated during early developmental stages, including egg and young larval (younger than third instar) stages, by using NIRS technology with up to 95% accuracy. NIRS technology could significantly improve pest diagnosis in cotton pest management.     

Influence of morphology on the near-infrared spectra of mycelial biomass and its implications in bioprocess monitoring

Bioprocesses that employ mycelial microorganisms are commercially important. The application of optical techniques for the measurement of biomass in such processes is limited by the morphological heterogeneity exhibited by the mycelial microorganism employed. We investigated the influence of morphology on the near-infrared (NIR) spectra of the biomass of Streptomyces fradiae, a filamentous microorganism, by studying the spectra of mycelial suspensions that were manipulated to generate a range of morphological forms. Computerized image analysis was used to characterize the morphological forms. Principal component analysis was used to assess the spectral variations and study correlations to the manipulated mycelial morphology. Although morphology was found to influence the near infrared transmittance spectra of biomass, the influence was less pronounced than in the visible region, the spectral information at longer wavelengths (1600-2350 nm) showing greater stability to morphological variations. Long-wave NIR spectral information is therefore likely to be more useful in estimating biomass in mycelial bioprocesses. Furthermore, the NIR reflectance spectra of dried biomass were found to show correlations to the morphological variations introduced, suggesting that NIR spectra may be useful in obtaining morphology related information.