Real-Time Determination of Structural Changes of Sodium Caseinate-Stabilized Emulsions Containing Pectin Using High Resolution Ultrasonic Spectroscopy

The interactions that lead to structure transitions in oil-in-water emulsions were investigated using high-resolution ultrasonic spectroscopy. High methoxyl pectin (HMP) was added to the emulsions at various concentrations and the dynamics of aggregation induced by changes in pH were observed. Two independent ultrasonic parameters, velocity and attenuation, were measured as a function of time or pH. At pH 6.8, both velocity and attenuation of sound changed as a function of HMP concentration. During acidification, caused by the addition of glucono-δ-lactone, there were small changes in the overall ultrasonic velocity, but it was possible to relate these changes to the structural changes in the emulsion. The values of ultrasonic attenuation decreased at high pH with increasing amount of HMP, indicating changes in the flocculation state of the oil droplets caused by depletion forces. During acidification at pH 5.4, emulsions containing HMP showed a steep increase in the ultrasonic attenuation, and this pH corresponds to the pH of association of HMP with the casein-covered oil droplets. The adsorption of HMP onto the interface causes a rearrangement of the oil droplets, and the emulsions containing sufficient amounts of HMP no longer gel at acid pH. This is well described by the ultrasonic attenuation changes in the various emulsions. This research demonstrated for the first time that ultrasonic spectroscopy can be employed for in situ monitoring and analysis of acid-induced destabilization of food emulsions.     

超声空化效应和超声微泡在生物医学中的应用

近年来,随着超声技术在医疗领域的广泛应用及超声造影剂研制的进展,空化效应和超声造影剂协同运用作为一种高效、安全、操作简单,且具有一定靶向性的无创治疗手段,在基因治疗、药物输送、溶栓和治栓,以及炎症与肿瘤的靶向诊断与治疗方面显示了巨大的运用潜力。简要综述了超声空化效应和超声微泡的治疗机制及应用。     

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。     

High-Resolution Proton Magnetic Resonance Spectroscopy of Rabbit Brain: Regional Metabolite Levels and Postmortem Changes

The changes in 16 cerebral metabolites produced by cardiac arrest and subsequent room temperature autolysis were studied using high-resolution proton nuclear magnetic resonance spectroscopy. Biopsies of rabbit cerebral cortex, cerebral white matter, and cerebellum were quantitatively analyzed for acetate, alanine, gamma-aminobutyric acid, creatine, glutamate, glycine, inositol, lactate, N-acetylaspartate, phosphocreatine, succinate, taurine, and threonine. Of these, N-acetylaspartate and the total creatine pool are the best candidates for use as concentration reference standards linking in vitro to in vivo 1H nuclear magnetic resonance measurements. Both changed little immediately after death, and they varied in a distinctive way among cortex, white matter, and cerebellum.     

Dependence of Laser-induced Breakdown Spectroscopy Results on Pulse Energies and Timing Parameters Using Soil Simulants

The dependence of some LIBS detection capabilities on lower pulse energies (<100 mJ) and timing parameters were examined using synthetic silicate samples. These samples were used as simulants for soil and contained minor and trace elements commonly found in soil at a wide range of concentrations. For this study, over 100 calibration curves were prepared using different pulse energies and timing parameters; detection limits and sensitivities were determined from the calibration curves. Plasma temperatures were also measured using Boltzmann plots for the various energies and the timing parameters tested. The electron density of the plasma was calculated using the full-width half maximum (FWHM) of the hydrogen line at 656.5 nm over the energies tested. Overall, the results indicate that the use of lower pulse energies and non-gated detection do not seriously compromise the analytical results. These results are very relevant to the design of field- and person-portable LIBS instruments.     

利用近红外光谱对杂种松及其亲本的鉴别分析

为了在林木育种和良种推广过程中对杂种松的真实性进行简单、快速鉴别,本研究以我国南方培育推广的2个杂种松及其3个亲本树种为研究材料,通过近红外光谱仪扫描各树种的针叶来采集数据,最后采用PLS-DA（偏最小回归-判别分析）方法建模对杂种松及其亲本进行鉴别。研究结果显示：本研究中PLS-DA方法对杂种松具有较高的判别能力,可以较好地将研究的2个杂种松及其3个亲本树种区别开来。因此,近红外光谱结合PLS-DA判别分析方法可以用来分析鉴别松树中的杂种和纯种,相对于同工酶和分子标记这些种质鉴别方法,近红外光谱技术具有简便、快捷等优点,值得在林木种质判别分析中进一步研究利用。     

Application of Surface-Enhanced Raman Spectroscopy for Detection of Beta Amyloid Using Nanoshells

Currently, no methods exist for the definitive diagnosis of AD premortem. β-amyloid, the primary component of the senile plaques found in patients with this disease, is believed to play a role in its neurotoxicity. We are developing a nanoshell substrate, functionalized with sialic acid residues to mimic neuron cell surfaces, for the surface-enhanced Raman detection of β-amyloid. It is our hope that this sensing mechanism will be able to detect the toxic form of β-amyloid, with structural and concentration information, to aid in the diagnosis of AD and provide insight into the relationship between β-amyloid and disease progression. We have been successfully able to functionalize the nanoshells with the sialic acid residues to allow for the specific binding of β-amyloid to the substrate. We have also shown that a surface-enhanced Raman spectroscopy response using nanoshells is stable and concentration-dependent with detection into the picomolar range.     

Femtosecond IR Pump-Probe Spectroscopy of Nonlinear Energy Localization in Protein Models and Model Proteins

This paper reviews our experimental and theoretical efforts toward understanding vibrational self-trapping of the amide I and N–H mode of crystalline acetanilide (ACN), other similar hydrogen-bonded crystals, as well as of model peptides. In contrast to previous works, we used nonlinear IR spectroscopy as the experimental tool, which is specifically sensitive to the anharmonic contributions of the intramolecular interactions (as the nonlinear IR response of set of harmonic oscillators vanishes exactly). Our work reconfirms the previous assignment of the two bands of the amide I mode of ACN as being a self-trapped and a free exciton state, but in addition also establishes the lifetimes of these states and identifies the relevant phonons. Furthermore, we provide evidence for vibrationally self-trapped states also in model α-helices. However, given the short lifetime, any biological relevance in the sense of Davydov’s initial proposal can probably be ruled out.     

High-Resolution Gene Flow Model for Assessing Environmental Impacts of Transgene Escape Based on Biological Parameters and Wind Speed

Environmental impacts caused by transgene flow from genetically engineered (GE) crops to their wild relatives mediated by pollination are longstanding biosafety concerns worldwide. Mathematical modeling provides a useful tool for estimating frequencies of pollen-mediated gene flow (PMGF) that are critical for assessing such environmental impacts. However, most PMGF models are impractical for this purpose because their parameterization requires actual data from field experiments. In addition, most of these models are usually too general and ignored the important biological characteristics of concerned plant species; and therefore cannot provide accurate prediction for PMGF frequencies. It is necessary to develop more accurate PMGF models based on biological and climatic parameters that can be easily measured in situ. Here, we present a quasi-mechanistic PMGF model that only requires the input of biological and wind speed parameters without actual data from field experiments. Validation of the quasi-mechanistic model based on five sets of published data from field experiments showed significant correlations between the model-simulated and field experimental-generated PMGF frequencies. These results suggest accurate prediction for PMGF frequencies using this model, provided that the necessary biological parameters and wind speed data are available. This model can largely facilitate the assessment and management of environmental impacts caused by transgene flow, such as determining transgene flow frequencies at a particular spatial distance, and establishing spatial isolation between a GE crop and its coexisting non-GE counterparts and wild relatives.     

Dielectric Spectroscopy: a Rapid Method for the Determination of Solvent Biocompatibility During Biotransformations

Dielectric spectroscopy provides a convenient means of determining the degree of intactness of biological cells. 4-terminal dielectric measurements of suspensions of Saccharomyces cerevisiae at 0.4 MHz show that, as with all other biological cells, these organisms possess a substantial β-dispersion. The additional of octanol to such suspensions causes a rapid decrease in the electrical capacitance of the suspension, which parallels the cellular viability as determined by methylene blue staining. The kinetics of cell death are determined in part by the rate of dissolution of the organic solvent in the aqueous phase. The toxicity of several organic solvents to S. cerevisiae is studied using this technique, and is found to be dependent upon the polarity of the solvent. The present method provides a simple and rapid means for assessing the biocompatibility of solvents used in biotransformations.     

MRS脑肿瘤分型诊断模型研究

基于对核磁波谱(MR Spectroscopy)的特征变量提取,利用模糊聚类算法来构建脑肿瘤分型诊断模型,实验结果表明该模型能准确对神经胶质细胞瘤分级诊断,为进一步实现更复杂的脑肿瘤诊断系统模型提供方法。     

Ultrasonic wave spectroscopy study of sugar oligomers and polysaccharides in aqueous solutions: the hydration length concept

The determination of apparent persistence length and radius of gyration of maltodextrins in water is achievable through high-resolution ultrasonic spectroscopy measurements. Classical hydration number for those carbohydrates is characteristic of an apparent persistence degree of polymerisation of the polymer. A force-field based molecular modeling of a 10DP malto-oligomer allows measurement of the corresponding length for the lowest energetic conformation in solution. A good agreement between the apparent radii of gyration determined by this technique and the freely rotating polymer chain model is found with radii of gyration calculated from the intrinsic viscosity.     

Nondestructive Measurement of Retinal Glucose Transport and Consumption In Vivo Using NMR Spectroscopy

Abstract: The cellular events underlying various retinopathies are poorly understood but likely involve perturbation of retinal glucose metabolism. Current methods for assessing this metabolism are destructive, thus limiting longitudinal studies. We hypothesize that following an intravitreous injection, the clearance rate of a glucose analogue will be a nondestructive index of retinal glucose transport and metabolism in vivo. First, radiolabeled glucose analogues were injected into the vitreous. After 40 min, the dominant clearance path was posterior via the retina and was consistent with a facilitated transport mechanism. Next, either [6,6-²H₂]glucose or 3-deoxy-3-fluoro- d -glucose was injected into the vitreous of rabbit eyes, and the clearance rate of each analogue was determined over 40 min using, respectively, ²H or ¹⁹F NMR. These rates were interpreted as a function of the retinal glucose transport and consumption. From the NMR data, the rate of retinal glucose consumption was ∼16 times slower than the transport of glucose. These data demonstrate that NMR measurements of glucose analogue clearance rate from the vitreous can provide a nondestructive index of retinal glucose transport and consumption in vivo.     

Decomposition and Mineralization of Organic Residues Predicted Using Near Infrared Spectroscopy

Characterization of decomposition characteristics is important for sound management of organic residues for both soils and livestock, but routine residue quality analysis is hindered by slow and costly laboratory methods. This study tested the accuracy and repeatability of near-infrared spectroscopy (NIR) for direct prediction of in vitro dry matter digestibility (IVDMD) and C and N mineralization for a diverse range of organic materials (mostly crop and tree residues) of varying quality (n = 32). The residue samples were aerobically incubated in a sandy soil and amounts of C and N mineralized determined after 28 days. IVDMD and quality attributes were determined using wet chemistry methods. Repeatability was higher with NIR than the original wet chemistry methods: on average NIR halved the measurement standard deviation. NIR predicted IVDMD and C and N mineralization more accurately than models based on wet chemical analysis of residue quality attributes: reduction in root mean square error of prediction with NIR, compared with using quality attributes, was IVDMD, 6%; C mineralization after 28 days, 8%; and N mineralization after 28 days, 8%. Cross-validated r ² values for measured wet chemistry vs. NIR-predicted values were: IVDMD, 0.88; C mineralization, 0.82; and N mineralization, 0.87. Direct prediction of decomposition and mineralization from NIR is faster, more accurate and more repeatable than prediction from residue quality attributes determined using wet chemistry. Further research should be directed towards establishment of diverse NIR calibration libraries under controlled conditions and direct calibration of soil quality, crop and livestock responses in the field to NIR characteristics of residues.     

抗癌药药效和机理评价新模式—Raman光谱分析

本文介绍了一个新的应用Ｒａｍａｎ光谱法进行抗癌药物筛选,药效评价和机理分析的模式,该模式引用了一个重要的评价标准是Ｒａｍａｎ光谱中的费米共振一酪氨酸双峰比率值（ＴＤＲ）。这是一个在拉曼光谱学中被广泛应用的概念,本文详细介绍了整个模式中每一个应用部分的具体操作过程,以及应该注意的事项。结果证明这套模式具有实验周期短,结果准确,对抗癌药物的合成,改进与推广具有一定的实用价值。     

A Standardized Test for the Identification and Characterization of Melanins Using Electron Paramagnetic Resonance (EPR) Spectroscopy

Melanins are complex, incompletely understood polymeric pigments that historically have been difficult to investigate with common chemical, histochemical, and physicochemical techniques. Because these pigments uniquely contain a stable population of organic free radicals, electron paramagnetic resonance (EPR) spectroscopy is a particularly effective method for studying them, and a set of qualitative EPR criteria has been established for their identification. However, a number of practical problems have arisen in applying these criteria to identify and characterize unknown pigments in relatively scarce pathological specimens, indicating that a standardized approach is needed. As reported here, a standardized EPR test for melanin based on the EPR criteria has been developed, guided by the requirements that it be sensitive, accurate, simple, and easy to interpret. It has been evaluated using the well-characterized synthetic melanin prepared by alkaline autooxidation of 5,6-dihydroxyphenylalanine (Dopa) and initially applied to the identification and characterization of an unknown pigment purified from an unusual malignant lung tumor.     

胃粘膜正常和癌变细胞基因组DNA的表面增强拉曼光谱研究

通过测试胃粘膜正常上皮细胞、高、中、低和未分化胃癌细胞基因组DNA的表面增强拉曼光谱,分析各自特征性谱峰。结果表明：正常和高分化细胞基因组DNA在1060cm^-1。被抑制,只在1010cm^-1。被激活,但后者的谱峰更强且出现“红移”,其DNA链结构出现不稳定;中、低、未分化细胞基因组DNA中以上两种振动模式都被激活,说明它们的DNA链出现了断裂,且呈现渐强的趋势。同时也说明了脱氧核糖基在恶性程度越高的细胞基因组DNA中带正电趋势越强。1100—1670cm^-1谱带属于dC,dG,dA,dT的综合振动叠加,恶性程度越高的癌细胞中更多的模式被激活。可见,分化越低的胃癌细胞基因组DNA具有更多的振动模式被激活,与正常的差异更明显,并且DNA链整体带正电的趋势也可能越强,提示可能有更多的氧化反应发生。     

Comparison of 5 Thyroid Ultrasound Stratification Systems for Differentiation of Benign and Malignant Nodules and to Avoid Biopsy Using Histology as Reference Standard

ObjectiveWe aimed to compare the thyroid ultrasound risk stratification systems (RSSs) of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS), European TI-RADS, Korean TI-RADS, and American Thyroid Association (ATA), American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi guidelines to differentiate benign from malignant thyroid nodules and to avoid unnecessary fine needle aspiration (FNA).MethodsThe records of 1143 nodules ≥1 cm that underwent FNA biopsy and thyroidectomy between 2012 and 2020 at our institution were reviewed. Ultrasound categories and FNA recommendation indications of 5 international RSSs were compared with histopathological findings as benign or malignant. The ultrasound categories and recommended FNA indications, the proportion of the avoidable FNA procedures, and false negative rates (FNRs) by different systems were compared with each other.ResultsOf the 1143 nodules, 45% had thyroid malignancy. FNA recommendation and ultrasound risk classification of ATA guidelines had the highest area under curves of 0.619, and 0.715, respectively. ACR TI-RADS, American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines, European TI-RADS, ATA guidelines, and Korean TI-RADS would have avoided FNA for 34.7%, 31%, 25.7%, 20%, and 6% of nodules with an FNR of 24%, 28.5%, 22%, 7.2%, and 1.9%, respectively.ConclusionOur findings showed that all RSSs classified the nodules appropriately for malignancy. ATA guidelines had the highest area under curves and a low FNR, whereas ACR TI-RADS would have spared more patients from FNA with a high FNR.