PROGRESS IN NMR APPLICATIONS TO WELL LOGGING AND FORMATION EVALUATION

Since its discovery in 1946, NMR has become a valuable tool in physics, chemistry, biology, and medicine. With the invention of NMR logging tools that take the medical MRI or laboratory NMR equipment and turn it inside-out, the application of sophisticated laboratory techniques to determine formation properties in situ is now available. The capability has opened a new era in formation evaluation just as the introduction of NMR has revolutionized the other scientific areas.     

Homogeneous chemiluminescence system in neutral and near neutral aqueous solution with ClO2 as oxidant and its analytical application

Using ClO₂ as chemiluminescence (CL) oxidant, a novel homogeneous CL system in neutral and near neutral aqueous solution is proposed in this paper. ClO₂ could oxidize sulfite in pH 5.0–8.5 acetate buffer to produce CL emission, and pipemidic acid could sensitize the CL system. The ClO₂–SO₃²⁻–pipemidic acid reaction was used as a model CL system and explored the possibility of highly active and eco-friendly ClO₂ being used as CL oxidant in neutral and near neutral aqueous solution. Combined with flow-injection analysis, the proposed CL system was applied to the automated dissolution testing of pipemidic acid tablet. Compared with the common strong acidic or strong basic CL system, this proposed CL owns its advantages.     

抗拔非柱面改型钉的滚压加工及模具的设计计算

为了合理设计抗拔非柱面改型钉的滚压模具及加工设备，从改型钉的结构分析入手，研究分析了改型钉的成型原理和变形过程。在生产实践的基础上，提出了两种常用改型钉的参数及其滚压加工的工艺原理。     

用于接触面模拟的三维非线性接触单元

提出了一种新的模拟结构缝或接触问题的三维非线性接触单元,在本构关系上,模型同时考虑了已被大量实验证实的接触面法向和切向的非线性特性,法向采用了考虑法向变形的双曲线模型,切向采用了考虑应变化的双曲线模型,模拟了接触面的粘结、滑移和开裂等非线性现象,相对于其它接触单元,本文模型避免了Goodman单元等只考虑缝面变形及法向、切向参数取值的任意性,计算结果常使法向应力出现波动和过量嵌入等缺点,并据此编制了有限元计算程序,利用此程序分析了3个典型算例,验证了模型的合理性和程序的计算精度。     

城市交通生态占用研究--以北京市为例

为了反映城市不同交通工具对自然生态环境产生的压力和影响程度,基于生态占用理论和方法,计算了2002年北京市公共电汽车、地铁、轻轨、出租车、小公共汽车和私家车等主要交通工具的生态占用.结果表明:私家车生态占用约为7.27×105hm2;出租车生态占用约为2.42×105hm2;公共电汽车生态占用约为1.59×105hm2;小公共汽车生态占用约为0.71×105hm2;地铁生态占用约为0.32×105hm2;轻轨生态占用约为0.23×105hm2.私家车的人均生态占用是公共汽车人均生态占用的5.67倍.这证实私家车对生态环境的威胁和压力比公共交通工具对生态环境的威胁和压力大.优先发展城市公共交通,适度限制发展私人交通是实现城市交通可持续发展的必然选择.     

超声测距系统的高精度中心椭圆算法

描述了基于新型驱动电路和低噪声程控放大器的超声测距系统.驱动系统的设计从硬件角度提高了回波信号的信噪比和稳定性.基于能量重心校正法和最小二乘法的原理,提出了一种改进型椭圆中心超声回波寻峰算法:通过曲线拟合搜索椭圆中心点,即回波信号能量集中点,进而找到回波信号的峰值点.测试比较证明,与包络线法和三次多项式法相比,此算法测量相对误差稳定在0.2%,适用高精度工业测量.     

An Integrated Mass Spectrometry-Based Glycomics-Driven Glycoproteomics Analytical Platform to Functionally Characterize Glycosylation Inhibitors

Cancer progression is linked to aberrant protein glycosylation due to the overexpression of several glycosylation enzymes. These enzymes are underexploited as potential anticancer drug targets and the development of rapid-screening methods and identification of glycosylation inhibitors are highly sought. An integrated bioinformatics and mass spectrometry-based glycomics-driven glycoproteomics analysis pipeline was performed to identify an N-glycan inhibitor against lung cancer cells. Combined network pharmacology and in silico screening approaches were used to identify a potential inhibitor, pictilisib, against several glycosylation-related proteins, such as Alpha1-6FucT, GlcNAcT-V, and Alpha2,6-ST-I. A glycomics assay of lung cancer cells treated with pictilisib showed a significant reduction in the fucosylation and sialylation of N-glycans, with an increase in high mannose-type glycans. Proteomics analysis and in vitro assays also showed significant upregulation of the proteins involved in apoptosis and cell adhesion, and the downregulation of proteins involved in cell cycle regulation, mRNA processing, and protein translation. Site-specific glycoproteomics analysis further showed that glycoproteins with reduced fucosylation and sialylation were involved in apoptosis, cell adhesion, DNA damage repair, and chemical response processes. To determine how the alterations in N-glycosylation impact glycoprotein dynamics, modeling of changes in glycan interactions of the ITGA5–ITGB1 (Integrin alpha 5-Integrin beta-1) complex revealed specific glycosites at the interface of these proteins that, when highly fucosylated and sialylated, such as in untreated A549 cells, form greater hydrogen bonding interactions compared to the high mannose-types in pictilisib-treated A549 cells. This study highlights the use of mass spectrometry to identify a potential glycosylation inhibitor and assessment of its impact on cell surface glycoprotein abundance and protein–protein interaction.