Measurement of very low-molecular weight metabolites by traveling wave ion mobility and its use in human urine samples

The collision cross-sections(CCS)measurement using ion mobility spectrometry(IMS)in combination with mass spectrometry(MS)offers a great opportunity to increase confidence in metabolite identification.However,owing to the lack of sensitivity and resolution,IMS has an analytical challenge in studying the CCS values of very low-molecular-weight metabolites(VLMs250 Da).Here,we describe an analytical method using ultrahigh-performance liquid chromatography(UPLC)coupled to a traveling wave ion mobility-quadrupole-time-of-flight mass spectrometer optimized for the measurement of VLMs in human urine samples.The experimental CCS values,along with mass spectral properties,were reported for the 174 metabolites.The experimental data included the mass-to-charge ratio(m/z),retention time(RT),tandem MS(MS/MS)spectra,and CCS values.Among the studied metabolites,263 traveling wave ion mobility spectrometry(TWIMS)-derived CCS values(TWCCSN2)were reported for the first time,and more than 70%of these were CCS values of VLMs.The TWCCSN2 values were highly repeatable,with inter-day variations of<1%relative standard deviation(RSD).The developed method revealed excellent TWCCSN2 accuracy with a CCS difference(DCCS)within±2%of the reported drift tube IMS(DTIMS)and TWIMS CCS values.The complexity of the urine matrix did not affect the precision of the method,as evidenced by DCCS within±1.92%.According to the Metabolomics Standards Initiative,55 urinary metabolites were identified with a confidence level of 1.Among these 55 metabolites,53(96%)were VLMs.The larger number of confirmed compounds found in this study was a result of the addition of TWCCSN2 values,which clearly increased metabolite identification confidence.

Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes

Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs.The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)steps.First,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual microneedle.Then,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate.Subsequently,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures.Depending on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the substrate.With these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si wafer.Insertion tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain.To demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding processes.The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on.

Variation of Ionization Mechanisms with q in the Collision of He^2＋ with C^q＋

The ionization process in the collisions of He^2＋ with C^q＋ （q = 0-5） is investigated by using the continuum-distorted-wave eikonal-initial-state approximation. Double-differential cross sections for 1s and 2s sub-shells are obtained at the electron-ejected angle θ = 0° with the projectile energy ranging from 30keV/u to 10MeV/u. Variation of ionization mechanisms with q in C^q＋ is studied, and the dependences on the projectile energies and target sub-shells are also discussed. It is found that in the whole energy range, the absolute values of soft collision （SC） and binary encounter （BE） peaks decrease with increasing q. For the lower incident energies, the electron capture to the projectile continuum （ECC） peak decrease with increasing q as well as SC and BE peaks. For the higher incident energies （〉 1 MeV/u）, the absolute value of ECC peak increases with increasing q, so that the crossings of cross sections appear for C^q＋ with different q. This can be explained by the matching of velocities between the projectile and the electron initially bound to the target.

Polarization of Radiation Emitted after Electron Impact Excitation

A programme is developed to calculate the polarizations of the radiation emitted after electron impact excitation. The fully relativistic distorted-wave method is used in cross-section calculations. The programme is applied to He- and Li-like ions. The calculated values of line polarization are compared with other theoretical results and experimental values. For He-like U, at lower incident energy, the present polarization agrees with the other theoretical ones within 1%, while at higher energy, the differences increase up to about 10%. For He-like Fe and Ti, the present results of polarization degree for most of the lines agree with the experimental data within the experimental error bars. For the Li-like Ti line q （ls2s2p^2p3/2 to ls^22s）, the present value of the polarization agree excellently with another theoretical one, and both the values are consistent with the measured data within the experimental error bar.

Photon Angular Distribution and Polarization of Radiative Recombination

A systematic study is carried out on the angular distribution and polarization of photons emitted following radiative-recombination of bare and He-like ions of Ne, At, Ni and Mo with a unidirectional electron beam. In order to incorporate the screening effect due to inner-shell electrons, a distorted wave method is used. Scaling rules for polarization of the photon following radiative recombination to both bare and He-like ions are given for the incident energy regions up to six times the ionization threshold energy of the final state.

Single-and-double electron loss of O^(2+) in collisions with argon and helium

This paper reports that the ratios of double to single electron loss cross-section （R） of O^2＋ in collision with Ar and He at the velocity of 1 -4 vo（vo is the Bohr velocity） have been obtained by the coincidence technique. The trend of R - V in the experiment indicates that the effective charge varies with injected velocity. The effective charge can be obtained by the n-body classical trajectory Monte Carlo method, which is interpreted by the molecular Coulomb over barrier model.

The direct ionization processes in the collisions of partially stripped carbon and oxygen ions with helium atoms at low-to-intermediate energies

The values of direct double- to-single ionization ratio R of helium atoms induced by C^q＋, O^q＋ （q = 1 -4） ions at incident energies from 0.2 to 8.5MeV are measured. Based on the existing model （Shao J X, Chen X M and Ding B W 2007 Phys. Rev. A 75 012701） the effective charge of the projectile is introduced to theoretically estimate the value of R for the partially stripped ions impacting on helium atoms. The results calculated from our ＂effective charge＂ model are in good agreement with the experimental data, and the dependence of the effective charge on the ionization energy of the projectile is also discussed qualitatively.

Multi-Electron Processes in 4.15-11.08 keV/u^13C^6＋ on Argon Collisions

The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].

Changes in tumor-antigen expression profile as human small-cell lung cancers progress

Objective： Our group has previously observed that in patients with small-cell lung cancers （SCLCs）, the expression of a tumor antigen, glioma big potassium （gBK） ion channel, is higher at the time of death than when the cancer is first treated by surgical resection. This study aimed to determine whether this dichotomy was common in other potential lung tumor antigens by examining the same patient samples using our more extensive profile analysis of tumor-antigen precursor protein （TAPP）. We then tested the hypothesis that therapeutic intervention may inadvertently cause this increased gBK production. Methods： SCLC samples （eight surgical resections and three autopsy samples） and three control lungs were examined by quantitative real-time polymerase chain reaction for 42 potential TAPPs that represent potential T-cell-mediated immunological targets. Results： Twenty-two TAPP mRNAs displayed the same profile as gBK, i.e., more mRNAs were expressed at autopsy than in their surgical counterparts. B-cyclin and mouse double minute 2, human homolog of PS3-binding protein were elevated in both autopsy and surgical specimens above the normal-lung controls. When HTB119 cells were incubated with doxorubicin, gBK was strongly induced, as confirmed by intracellular flow cytometry with a gBK-specific antibody. Conclusion： Our findings suggested that more immunological targets became available as the tumor responded to chemotherapy and proceeded toward its terminal stages.

Nanoscale Track Diameter and Hydrogen Yield: Dependence upon Charge State of Incident Ion on Polystyrene

The study of radiation damage of high- molecular weight substances due to MeV ion interactions is of interest for engineering and scientific applications. In the present study polystyrene (PS) was irradiated with 107Ag ions of three different charge states (q) 11+, 14+ and 25+ and of 130 MeV energy. The emission of hydrogen from PS was monitored as a function of the incident ion fluence. The experimental results showed that the hydrogen depletion per incident ion from PS varies as qn, where n was found to be 2.1 as compared to the value 2.7 to 3.0 reported in the literature. Radii of the nanometric damaged zones or ion tracks formed were analyzed from the slope of the hydrogen depletion versus ion fluence curves as a function of charge state of incident ion. These have values between 3.2 - 6.8 nm. These radii were found to depend upon the charge state of the incident ion and vary as qm, where m has the value 0.9.

On the Nature of the Average Transverse Momenta of the Low-<i>pT</i>Secondaries in Some High Energy Nuclear Collisions

That the values of average transverse momenta ( ) of the secondaries produced in high energy collisions rise very slowly with energy is modestly well-known and accepted. We would like to probe into this aspect of the problem for production of the main variety of the 'soft' secondaries in two high energy symmetric nuclear collisions with the help of two non-QCD models. Our model-based results are found to be quite consistent with the anticipated behaviours and also with the observations.

Rapidity and Pseudorapidity Distributions of theVarious Hadron-Species Produced in High EnergyNuclear Collisions: A Systematic Approach

With the help of a phenomenological approach outlined in the text in some detail, we have dealt here with the description of the plots on rapidity and pseudorapidity spectra of some hadron-secondaries produced in various nucleus-nucleus interactions at high energies. The agreement between the measured data and the attempted fits are, on the whole, modestly satisfactory excepting a very narrow central region in the vicinity of y = η = 0. At last, hints to how the steps suggested in the main body of the text to proceed with the description of the measured data given in the plots could lead finally to a somewhat systematic methodology have also been made.

基于大数据的动力锂电池可靠性关键技术研究综述

锂离子电池作为电动汽车的主流储能元件,其可靠性下降将导致电动汽车性能异常退化或故障频发,甚至引发安全事故,发展先进的电池故障诊断与健康状态预估技术已成为动力锂电池可靠性领域的研究热点,而大数据与电动汽车的深度融合为电池可靠性关键技术发展提供了新思路。因此,本文首先介绍新能源汽车大数据平台的数据特点与数据清洗方法,简要回顾了大数据背景下可靠性关键技术在电动汽车与大数据平台的应用现状。然后围绕动力锂电池可靠性关键技术中电池故障诊断与健康状态预估研究,以数据驱动模型为核心,整理了基于大数据的电池故障诊断和健康状态预估的研究现状与方法,分析了电池故障诊断中基于机器学习、统计学、信号学、融合模型的优势与不足;对电池健康预估中基于历史运行数据、增量容量分析法提取特征的理论基础与电池健康预估模型进行综述。最后总结了当前研究在数据清洗、电池故障诊断和健康状态预估方面的局限性与面临的挑战,展望动力锂电池可靠性关键技术的未来发展方向。

钻井液智能检测评价系统的研制与现场应用

钻探过程中钻井液性能的实时检测、数据云储、智能诊断、自动优化建议,是油气行业实现智能化、数字化转型的先决要素,为此研发出一套基于行业标准、现场施工要求、配合物联网及大数据平台相结合的钻井液智能检测系统。该系统可在常温~200℃,常压~8 MPa条件下进行24H*365D的全时段、全自动、不间断检测不同钻井液体系性能参数,测试范围包括钻井液温度、密度、流变参数、中压及高温高压滤失量参数和滤液离子参数的变化,并根据智能分析模块对钻井液的实时参数与设计参数进行对比分析,及时提供钻井液优化建议,保证井下施工安全。通过长期室内检测及现场多口试验井数千组实验对比数据得出,流变模块及滤失模块准确率97.3%,离子测试模块准确率96.2%,为安全、高效、智能的油气勘探开发前景提供了精确、稳定的数据保障。

四环素类药物在体内存在状态的研究

研究了四环类药物与金属离子、生物大分子、有机小分子的相互作用，模拟体内环境研究了这些物质对药物的竞争作用，初步证明这些药物分子在体内存在的状态．

缓冲液成分对介电泳力的影响

在介电泳研究中,缓冲液对微粒运动情况的影响是不可忽略的,而目前关于缓冲液的研究关注则较少。文章旨在研究缓冲液中的大分子与离子对介电泳操纵的贡献。通过观察酵母菌在不同成分、不同配比的缓冲液中的运动情况,说明了缓冲液中大分子成分的增加可以降低溶液电导率而在同样电导率的溶液中对微粒的介电泳操纵影响不大,而离子的增多会增大溶液电导率,而在同样的电导率下会增加介电泳对微粒操纵的困难程度。

反渗透技术在大型合成氨装置水处理中的应用

四川美丰化肥分公司将先进的反渗透水处理技术应用于新建的大型合成氨装置的给水处理,取得了良好的经济效益和社会效益。

离子交换法处理仲钨酸铵结晶母液试验与实践

采用大孔弱碱性树脂在弱酸性条件下吸附仲钨酸铵结晶母液中的钨 ,同时除去大部分C1-,用NaOH进行解吸 ,所得Na2WO4 返回主工艺流程。该法简单可行 。

动力型锂离子电池导电剂的研究及展望

导电剂是锂离子电池不可缺少的关键材料之一,特别是在动力型锂离子电池的大电流充放电过程中具有十分重要的作用。由于电极材料的导电率低等原因,传统导电剂已不能满足动力型锂离子电池大电流和快速充放电的要求,必须研发和使用高效导电剂来提高或改善电池的充放电安全性、高温稳定性、电池容量和寿命。本文从作用机理出发探讨了导电剂的品质种类、改性处理、掺合比例等,并展望了新型导电剂的研发以及在动力型锂离子电池方面的发展前景。

产业集群的集聚度评价模型实证研究——以苏州市大数据产业为例

文章从大数据产业集群的内涵入手,提出了以专利和IT产业等指标的带权重因子的产业集聚度模型。并利用该模型对苏州市大数据产业集群现状进行实证分析,结果表明该模型的结果符合实际情况,模型是可行的和有效的,具有很好的实际应用价值。它为大数据及其它产业集群的研究提供了新的可行途径和有效手段。