HPLC-ELSD同时测定腺梗豨莶草中6个二萜成分的含量

为了研究腺梗豨莶草中6个二萜成分(对映海松烯型二萜:奇任醇、Hythiemoside B和豨莶精醇;对映贝壳杉烷型二萜:对映-17,18-二羟基-贝壳杉烷-19-羧酸、对映-16β,17-二羟基-贝壳杉烷-19-羧酸和对映-16α氢-贝壳杉烷-17,19-二羧酸)的含量,本试验建立了高效液相色谱法-蒸发光散射检测器(HPLC-ELSD)同时测定二萜类化合物含量。样品粉碎过筛加甲醇和乙酸乙酯回流提取,蒸发减压除去溶剂,甲醇溶解,0.45μm滤膜滤过,取续滤液进行测定。色谱条件:色谱柱为Waters Symmetry Shield^(TM)RP18柱(250 mm×4.6 mm,5μm),流动相为0.3%甲酸水溶液-乙腈(v/v),梯度洗脱,流速为1.0 mL/min。蒸发光散射检测器漂移管温度为103℃,雾化气流速为3.0 L/min。应用该方法测定腺梗豨莶草样品不同部位中6个二萜类化合物的含量,同时比较叶、枝、茎中对映海松烯型二萜、对映贝壳杉型二萜和总二萜含量的差异。结果显示,6个二萜成分在其线性范围内线性关系良好(r≥0.9992);日内和日间精密度相对标准偏差(RSD)均小于3.5%;回收率介于96.5%~101.5%,RSD均小于2.3%;腺梗豨莶草不同部位(叶、枝、茎)的二萜类化合物含量差异较大。结果表明,本试验所建立的HPLC-ELSD方法简便、准确、重复性好,为腺梗豨莶草药材全面的质量评价和临床应用中最佳药用部位的选择提供了参考。

Effect of sodium nitroprusside on the microrheological properties of red blood cells in di®erent media

Red blood cell(RBC)aggregation as well as their deformation signi¯cantly affects blood microrheology.These processes depend on various factors,one of which is concentration of the nitric oxide,one of the main signaling molecule in the bloodstream.The purpose of this study was to investigate the effect of nitric oxide on the microrheological properties of red blood cells(RBCs)in RBC samples of various media after the addition of nitric oxide donor sodium nitroprusside in vitro.Microrheological properties were measured using laser aggregometer and ektacytometer based on diffuse light scattering and diffraction of laser light on a suspension of RBCs,respectively.The study found that heparin-stabilized blood showed increased RBC aggregation and deformation with sodium nitroprusside concentrations of 100,and 200M,while EDTA-stabilized blood showed slightly decreased aggregation and unchanged deformation.With washed RBCs in dextran solution,the addition of sodium nitroprusside(in the concentrations of 100,and 200M)resulted in decreased aggregation and increased deformation.These-ndings aid in our understanding of nitric oxide's effect on RBC microrheological properties.

Mechanisms of ultrasonic modulation of multiply scattered incoherent light based on diffusion theory

An analytic equation interpreting the intensity of ultrasound-modulated scattering light is derived, based on diffusion theory and previous explanations of the intensity modulation mechanism. Furthermore, an experiment of ultrasonic modulation of incoherent light in a scattering medium is developed. This analytical model agrees well with experimental results,which confirms the validity of the proposed intensity modulation mechanism. The model supplements the existing research on the ultrasonic modulation mechanism of scattering light.

Evaluation of corneal backward light scattering in type 2 diabetes mellitus

AIM:To compare the corneal backward light scattering values in type 2 diabetes mellitus(DM)patients with those of age and sex-matched healthy controls.METHODS:The study included 30 patients(30 eyes)with type 2 DM and 30 control subjects(30 eyes).Duration of diabetes,most recent hemoglobin A1c levels,along with the status of diabetic retinopathy,and existing medical treatment of all subjects were recorded.All subjects underwent a complete ophthalmologic examination.In addition,backward light scattering(densitometry)was measured to assess changes in corneal transparency using tomography(Pentacam HR).RESULTS:The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females.The age was 50.40±7.80y(range:40-68y)of the diabetic group and 49.30±9.50y(rang:40-73y)of control group.The diabetic group demonstrated significantly higher mean densitometry values of the anterior(6-10 mm)zone(P=0.047),the total anterior layer(P=0.036)and the total cornea(P=0.043)than control group.The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration.CONCLUSION:Diabetic group has higher densitometry in anterior corneal(6-10 mm)zone,total anterior cornea,and total cornea and with no correlation with hemoglobin A1c levels and DM duration.

A novel mechanism of PHB2-mediated mitophagy participating in the development of Parkinson's disease

Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the mitochondrial inner membrane,and its role in Parkinson’s disease remains unclear.Protein kinase R(PKR)-like endoplasmic reticulum kinase(PERK)is a factor that regulates cell fate during endoplasmic reticulum stress.Parkin is regulated by PERK and is a target of the unfolded protein response.It is unclear whether PERK regulates PHB2-mediated mitophagy thro ugh Parkin.In this study,we established a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson’s disease.We used adeno-associated virus to knockdown PHB2 expression.Our res ults showed that loss of dopaminergic neurons and motor deficits were aggravated in the MPTP-induced mouse model of Parkinson’s disease.Ove rexpression of PHB2 inhibited these abnormalities.We also established a 1-methyl-4-phenylpyridine(MPP+)-induced SH-SY5Y cell model of Parkinson’s disease.We found that ove rexpression of Parkin increased co-localization of PHB2 and microtubule-associated protein 1 light chain 3,and promoted mitophagy.In addition,MPP+regulated Parkin involvement in PHB2-mediated mitophagy through phosphorylation of PERK.These findings suggest that PHB2 participates in the development of Parkinson’s disease by intera cting with endoplasmic reticulum stress and Parkin.

高效液相-蒸发光散射检测器(HPLC-ELSD)测定红参中的精氨酸单糖苷(AF)及精氨酸双糖苷(AFG)含量

目的建立一种同时测定人参加工品中精氨酸单糖苷(AF)和精氨酸双糖苷(AFG)含量的方法。[方法]用PrevailTMC18column(4.6 mm×250 mm,5μm)色谱柱进行检测。流动相A:色谱乙腈,流动相B:5.0mmol/L七氟丁酸的0.7%三氟醋酸溶液。色谱条件为[0%A(0 min);0%A(5 min);15%A(8 min);35%A(25 min)];流速0.8 mL/min;漂移管温度为115℃;气体流量3.2 L/min。[结果]AF和AFG的检测限分别为0.015和0.010 mg/mL;线性关系相关系数分别为,AF:0.9997,AFG:0.9999,表明线性关系良好。AF和AFG检测的精密度,重复性,稳定性以及回收率的相对标准偏差分别为0.43%&0.37%,0.43%&0.55%,0.43%&0.49%,0.45%&0.15%。AF和AFG检测的回收率分别为99.5%&100%,表明方法稳定。经检测,高丽红参,中国红参和生晒参中AF含量分别为0.74%,0.91%和1.14%,AFG含量分别为6.69%,5.12%和0.85%。[结论]这种方法成功用于高丽红参,中国红参及生晒参中AF及AFG的检测;且红参中AF和AFG含量明显高于生晒参。该方法测定结果可靠,缩短了测定时间,较少杂质干扰。但因为本研究考察氨基酸种类较少,当衍生物种类较多时,仍需进一步考察其分离度。

Faster than the Speed of Light Is a Quantum Phenomena

Classical Mechanics using Einstein’s theories of relativity places a limit on speed as the speed of light. Quantum Mechanics has no such limitation. To understand space accelerating faster than the speed of light and information being exchanged instantaneously between two entangled electrons separated by huge distances, one uses Planck’s length, Planck’s time, and Planck’s mass to indicate that space and time are discrete and therefore along with masses smaller than Planck’s mass are Quantum Mechanical in nature. Faster than the speed of light c = 3 × 108 m/s is a classical effect only in dimensions of space lower than our 3-D Universe, but it is a Quantum effect in all dimensions of space. Because space can oscillate sending out ripples from the source, it is the medium used for transporting light waves and gravity waves.

Developing a Model for Parkinson’s Disease Detection Using Machine Learning Algorithms

Parkinson’s disease(PD)is a chronic neurological condition that progresses over time.People start to have trouble speaking,writing,walking,or performing other basic skills as dopamine-generating neurons in some brain regions are injured or die.The patient’s symptoms become more severe due to the worsening of their signs over time.In this study,we applied state-of-the-art machine learning algorithms to diagnose Parkinson’s disease and identify related risk factors.The research worked on the publicly available dataset on PD,and the dataset consists of a set of significant characteristics of PD.We aim to apply soft computing techniques and provide an effective solution for medical professionals to diagnose PD accurately.This research methodology involves developing a model using a machine learning algorithm.In the model selection,eight different machine learning techniques were adopted:Namely,Random Forest(RF),Decision Tree(DT),Support Vector Machine(SVM),Naïve Bayes(NB),Light Gradient Boosting Machine(LightGBM),K-Nearest Neighbours(KNN),Extreme Gradient Boosting(XGBoost),and Logistic Regression(LR).Subsequently,the concentrated models were validated through 10-fold Cross-Validation and Receiver Operating Characteristic(ROC)—Area Under the Curve(AUC).In addition,GridSearchCV was utilised to measure each algorithm’s best parameter;eventually,the models were trained through the hyperparameter tuning approach.With 98%accuracy,LightGBM had the highest accuracy in this study.RF,KNN,and SVM came in second with 96%accuracy.Furthermore,the performance scores of NB and LR were recorded to be 76%and 83%,respectively.It is to be mentioned that after applying 10-fold cross-validation,the average performance score of LightGBM accounted for 93%.At the same time,the percentage of ROC-AUC appeared at 0.92,which indicates that this LightGBM model reached a satisfactory level.Finally,we extracted meaningful insights and figured out potential gaps on top of PD.By extracting meaningful insights and identifying potential gaps,our study contributes to the significance and impact of PD research.The application of advanced machine learning algorithms holds promise in accurately diagnosing PD and shedding light on crucial aspects of the disease.This research has the potential to enhance the understanding and management of PD,ultimately improving the lives of individuals affected by this condition.

Storage time affects the level and diagnostic efficacy of plasma biomarkers for neurodegenerative diseases

Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°C.We aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large cohort.Plasma samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline project.These samples were stored at-80°C for up to 6 years before being used in this study.Our results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage time.However,the level of total tau showed a negative correlation with sample storage time.Notably,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage time.This was not observed in individuals with cognitive impairment.Consequently,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage time.Therefore,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's disease.Furthermore,in cohort studies,it is important to consider the impact of storage time on the overall results.

Research on the Performance of Non-Line-of-Sight Ultraviolet Communication in Rain and Fog Environment

Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scattering characteristics can enable the wireless ultraviolet communication system to transmit ultraviolet light signals in a non-line-of-sight manner, which overcomes the weakness that other free space optical communications must work in a line-of-sight manner. Based on the basic theory of scattering and absorption in atmospheric optics, taking the ultraviolet light with a wavelength of 266 nm as an example, this paper introduces the classical model of non-line-of-sight single-scattering coplanarity based on the ellipsoid coordinate system. The model is used to simulate and analyze the relationship between the geometric parameters such as transmission distance, transceiver elevation angle and transceiver half-angle and the received optical power per unit area. The performance of non-line-of-sight ultraviolet communication system in rain and fog environment is discussed respectively. The results show that the transmission quality of non-line-of-sight ultraviolet atmospheric propagation is greatly affected by the communication distance. As the distance increases, the received light power per unit area gradually decreases. In addition, increasing the emission elevation angle, the receiving elevation angle and the receiving half angle is an important way to improve the system performance.

Data from Twenty-Three FRB’s Confirm the Universe Is Static and Not Expanding

Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This gives us the opportunity to test Dispersion Measure versus redshift predictions made by two models. The Macquart relation for an expanding Universe and the New Tired Light relationship in a static universe. In New Tired Light, redshifts are produced when a photon is absorbed and re-emitted by the electrons in the IGM which recoil on both occasions. Some of the energy of the photon has been transferred to the kinetic energy of the recoiling electron. The photon has less energy, a lower frequency and a longer wavelength. It has been redshifted. Since dispersion is due to an interaction between radio signals and these same electrons one would expect a direct relationship between DM and redshift in the New Tired light model. The relation is DM=(mec/2hre)ln(1+z)and contains no adjustable parameters—just a combination of universal constants related to the electron and photon. Notice that the relation is independent of the electron number density ne since a change in ne affects both the DM and redshift equally. A graph of DM versus ln(1 + z) will be a straight line of gradient (mec/2hre)and, using SI units, substituting for the constants gives 7.318 × 1025 m−2. Using the data from the 23 well localized FRB’s, with the weighting of the DM’s for expansion removed (so that the data corresponds to a static universe), a graph of DM versus ln(1 + z) has a gradient of 6.7 × 1025 m−2—9% below the predicted (mec/2hre). The Macquart relation involves highly processed data and adjustable parameters to allow for “dark energy” and “dark matter” (neither of which has yet been found) and can be reduced to DM = 850z (in units of pc∙cm−3). Using the data from this set of localized FRB’s gives a trendline with gradient 1.10 × 103 pc∙cm−3—almost 30% higher than that predicted in an expanding universe model. The FRB data clearly comes down in favour of a static universe rather than an expanding one. Combining the DM-z relationship for the 23 well localized FRB’s, with the Hubble diagram, drawn using the NED-D compilation of redshift independent extragalactic distances, produces a value of “ne” the mean electron number density of the IGM, of ne=0.48 m−3close to the value ne=0.5 m−3, long since predicted by NTL.

0D Cd-In-S固溶体的制备及其光催化降解性能研究

由于含有S 3p轨道,窄带隙金属硫化物的价带具有更高能级位置,能利用可见光降解有机污染物。文章通过一步法制备0D Cd-In-S三元固溶体,并考察其在可见光下催化降解甲基橙(methyl orange,MO)的性能。通过X-射线衍射(X-ray diffraction,XRD)、透射电子显微镜(transmission electron microscope,TEM)、紫外-可见吸收光谱(UV-vis)等测试手段对固溶体纳米颗粒的结构、形貌和光学性能进行表征。研究发现,与CdS、In_(2)S_(3)相比,合金化后的Cd-In-S固溶体具有更为优异的性质,其中Cd_(0.7)In_(0.3)S_(1.15)在60 min内对MO的降解效率可达93.47%,远高于纯CdS和In_(2)S_(3);电化学研究数据表明,高降解效率来自于适宜的带隙位置和带宽以及更高的光生电子空穴对分离效率。

HPLC-ELSD法同时测定电子烟烟液中的10种甜味剂

建立了高效液相色谱仪-蒸发光散射检测器(HPLC-ELSD)同时检测电子烟烟液中安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、阿力甜、新甲基橙皮苷二氢查尔酮(NHDC)、爱德万甜、罗汉果苷V、纽甜的方法。样品中的甜味剂经50%甲醇水提取后,采用C_(18)色谱柱分离,以甲醇-0.1%甲酸水(pH=4.5)为流动相进行梯度洗脱,蒸发光散射检测器进行检测。结果表明,10种甜味剂分离度良好,在5~250 mg/L建立二次曲线,R^(2)均大于0.998,方法回收率为90.0%~110.0%,RSD为0.774%~7.65%。检测方法简单、准确、灵敏、实用性强,适用于电子烟烟液中10种甜味剂的同时检测,提高了实验室的检测效率。

光诱导基于EDA机理构建S-芳基黄原酸酯新策略

黄原酸酯类化合物作为药物化学、农业化学、材料化学中重要的组成部分,一直备受化学家们的关注.寻找简单、高效合成S-芳基取代黄原酸酯的方法引起了研究者广泛的关注.报道了一种可见光诱导下基于硫负离子与噻蒽盐间的EDA(电子供体受体)过程实现C-S键构建的新策略.在温和无金属的条件下,以中等至优良的收率得到了一系列S-芳基黄原酸酯,克级实验与日光实验证明了反应的应用潜力,为黄原酸酯类化合物的合成提供了一种新思路.

银纳米线SERS快速高灵敏检测水中痕量Hg2+研究

水中痕量重金属汞离子(Hg^(2+))对人类健康会构成严重威胁,因此快速高灵敏检测水中痕量Hg^(2+)具有重要科学意义和实际应用价值。为实现这一目标,研究运用银纳米线(silver nanowires, AgNWs)作为表面增强拉曼散射(Surface-Enhanced Raman Scattering, SERS)基底来快速高灵敏检测水中痕量Hg^(2+)。用旋涂法制备了均匀分布的AgNWs基SERS基底,并用罗丹明6G(Rhodamine 6G,R6G)作为拉曼信标分子,以间接检测水中痕量Hg^(2+)。通过研究SERS活性、稳定性、重现性、选择性、AgNWs直径及pH值对其SERS活性的影响,用时域有限差分法(Finite Difference Time Domain, FDTD)模拟了AgNWs表面电场分布情况。结果显示,AgNWs基SERS基底具有良好的活性、优异的信号再现性、稳定性和选择性,SERS活性随着直径的增大而增强,对Hg^(2+)的检测限(Detection Of Limit, LOD)达10-11mol/L,远低于美国环境保护署(The U.S. Environmental Protection Agency, EPA)的饮用水Hg^(2+)浓度标准(10-8mol/L)。在低浓度范围内,SERS特征峰强度(R^(2)=0.9919)有良好的线性关系。FDTD模拟结果为试验结果提供了有力的理论支撑,可为水中检测痕量Hg^(2+)提供新策略,在环境监测中具有广阔的应用前景。

基于T-S模糊神经网络的光伏发电机组自动控制

光照情况变化会使光伏发电机组功率呈现不稳定性,加大光伏发电机组控制难度,为此,设计了基于T-S模糊神经网络的光伏发电机组自动控制方法。构建光伏阵列数学模型,分析在均匀和不均匀2种光照情况下光伏发电机组特性曲线。以分析结果为依据,采用T-S模糊神经网络构建光伏发电机组自动控制模型。为保证良好的控制效果,引入定比因子优化隶属度函数,输出最佳跟踪结果,结合最佳跟踪结果和自动控制模型实现光伏发电机组自动控制。测试结果显示,该方法能够完成光伏阵列特性分析,控制效果好。

RP-HPLC-ELSD法测定逍遥颗粒中柴胡皂苷c、a、d的含量

目的:采用反相高效液相色谱-蒸发光散射检测(RP-HPLC-ELSD)法同时测定逍遥颗粒中柴胡皂苷c、a、d三种成分的含量。方法:采用安捷伦(Agilent)SB-C18色谱柱(4.6mm×250mm,5μm),流动相为乙腈(A)-水(B)。梯度洗脱程序为0~18min,30%A;18~26min,35%~45%A;26~35min,45%~55%A。流速为1.0ml/min,柱温为30℃,气体流速为2.5L/min,蒸发温度为60℃,进样量为10μl。结果:柴胡皂苷c、a、d分别在0.950~19.000μg、1.088~21.760μg、1.520~30.400μg的范围内线性关系良好。柴胡皂苷c平均回收率为99.49%,RSD为0.35%(n=9);柴胡皂苷a平均回收率为99.99%,RSD为0.66%(n=9);柴胡皂苷d平均回收率为99.12%,RSD为0.47%(n=9)。结论:该方法准确、灵敏、重复性好,可作为逍遥颗粒中柴胡皂苷c、a、d的含量测定方法。

In-Situ Measuring the Particle Mean Size and Dust Concentration by Near-Forward Small Angle Light Scattering

This paper presents a method of measuring the particle mean size and dust concentration by small angle near forward light scattering optics and the extinction theory. Its theory is based on Fraunhofer diffraction theory which is the approximation of Mie scattering within the forward Fraunhofer diffraction lobe, and Rosin Rammler function is introduced to describe the particle size distribution in two phase flow in advance. Compared with the values by the sample weight method, the measurement results have a reasonable agreement. The present work has demonstrated that this method will be probably used to monitor the parameters of two phase flow.

Application of L-Cys-Capped CdS Nanoparticles in Determination of Nucleic Acid by Resonance Light-Scattering Technique

Aim To determine nucleic acid （DNA） using Nanometer-sized L-cysteine-capped CdS particles by resonance light scattering （RLS） method. Methods The nano-particles synthesized by a colloidal aqueous method were water-soluble, stable, and highly luminescent. The RLS of L-Cys-CdS particles were greatly quenched by DNA in Tris-HCl solutions. The intensity of RLS at 344 nm was proportional to the concentration of DNA. Results The linearity range of the calibration curve was 0. 01 - 1.0 μg·mL^-1 for calf thymus DNA and 0. 04 - 1.5 μg· mL^-1 for salmon sperm DNA. The detection limits （3 δ） were 8 ng·mL^-1 for calf thymus DNA and 10 ng·mL^-1 for salmon sperm DNA. Conclusion This method is simple, sensitive, and capable of avoiding the use of toxic dyes.

Automobile light control system based on CAN bus and contactless switch

In order to solve the complex wiring and low reliability of conventional light control system,an automobile contactless switch light system is designed combined with Hall element and controller area network （CAN） bus technology.The processing system of electromagnetic compatibility controlled by CAN bus is improved to reduce the electromagnetic interference from the controller and other sources of interference.With Freescale＇s high-performance single-chip MC9S08DZ60 and CAN transceiver TJA1050,the overall circuit design and software design are presented.The test results show that the designed light control system is feasible.