Sums of k-th powers and the Whittaker–Fourier coefficients of automorphic forms

The Ramanujan Journal - In this work, we obtain power-saving bounds for shifted convolution sums involving the Whittaker–Fourier coefficients of automorphic forms and $$r_{s, k}(n)$$ , the...     

Chemical Composition and In Vitro Antioxidant Activity of Sida rhombifolia L. Volatile Organic Compounds

In the current study, the phytochemical constituents of volatile organic compounds (VOCs) obtained from Sida rhombifolia L. were identified by GC-FID and GC-MS analysis. A total of 73 volatile organic compounds were identified. The major components of S. rhombifolia VOCs were identified as palmitic acid (21.56%), phytol (7.02%), 6,10,14-trimethyl-2-pentadecanone (6.30%), oleic acid (5.48%), 2-pentyl-furan (5.23%), and linoleic acid (3.21%). The VOCs are rich in fatty acids (32.50%), olefine aldehyde (9.59%), ketone (9.41%), enol (9.02%), aldehyde (8.63%), and ketene (6.41%). The antioxidant capacity of S. rhombifolia VOCs was determined by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt (ABTS), and ferric reducing/antioxidant power (FRAP) methods with butylated hydroxytoluene (BHT) and Trolox as standard. The VOCs showed dose-dependent antioxidant activity with IC50 (50% inhibitory concentration) values of 5.48 ± 0.024 and 1.47 ± 0.012 mg/mL for DPPH and ABTS assays, respectively. FRAP antioxidant capacity was 83.10 ± 1.66 mM/g. The results show that the VOCs distilled from S. rhombifolia have a moderate antioxidant property that can be utilized as a natural botanical supplement or an antioxidant.     

Crystal Structure of Human CD47 in Complex with Engineered SIRPα.D1(N80A)

Background: Targeting the CD47/SIRPα signaling pathway represents a novel approach to enhance anti-tumor immunity. However, the crystal structure of the CD47/SIRPα has not been fully studied. This study aims to analyze the structure interface of the complex of CD47 and IMM01, a novel recombinant SIRPα-Fc fusion protein. Methods: IMM01-Fab/CD47 complex was crystalized, and diffraction images were collected. The complex structure was determined by molecular replacement using the program PHASER with the CD47-SIRPαv2 structure (PDB code 2JJT) as a search model. The model was manually built using the COOT program and refined using TLS parameters in REFMAC from the CCP4 program suite. Results: Crystallization and structure determination analysis of the interface of IMM01/CD47 structure demonstrated CD47 surface buried by IMM01. Comparison with the literature structure (PDB ID 2JJT) showed that the interactions of IMM01/CD47 structure are the same. All the hydrogen bonds that appear in the literature structure are also present in the IMM01/CD47 structure. These common hydrogen bonds are stable under different crystal packing styles, suggesting that these hydrogen bonds are important for protein binding. In the structure of human CD47 in complex with human SIRPα, except SER66, the amino acids that form hydrogen bonds are all conserved. Furthermore, comparing with the structure of PDB ID 2JJT, the salt bridge interaction from IMM01/CD47 structure are very similar, except the salt bridge bond between LYS53 in IMM01 and GLU106 in CD47, which only occurs between the B and D chains. However, as the side chain conformation of LYS53 in chain A is slightly different, the salt bridge bond is absent between the A and C chains. At this site between chain A and chain C, there are a salt bridge bond between LYS53 (A) and GLU104 (C) and a salt bridge bond between HIS56 (A) and GLU106 (C) instead. According to the sequence alignment results of SIRPα, SIRPβ and SIRPγ in the literature of PDB ID 2JJT, except ASP100, the amino acids that form common salt bridge bonds are all conserved. Conclusion: Our data demonstrated crystal structure of the IMM01/CD47 complex and provides a structural basis for the structural binding interface and future clinical applications.     

聚合物载体-稀土金属配合物的研究聚（苯乙烯－丙烯酰胺）载体－氯化钕配合物对?

研究了聚（苯乙烯－丙烯酰胺）（ＰＳＡＣ）载体－氯化钕配合物催化丁二烯聚合的规律，考察了ＰＳＡＣ载体及ＰＳＡＣ·ＮｄＣｌ３配合物的组成与催化活性间的关系．ＰＳＡＣ载体的收率不影响配合物的活性，而配合物的活性却随ＰＳＡＣ载体中Ｃ（Ｏ）ＮＨ２功能团含量的高低而改变，含量低时活性高．ＰＳＡＣ载体与配合物的组成不影响所得聚丁二烯的微观结构     

Morphology, structure and Raman scattering of carbon nanotubes produced by using mesoporous materials

Carbon nanotubes were prepared by chemical vapor deposition (CVD) of hydrocarbon gas on various substrates. The effect of substrates on the growth, morphology and structure of carbon nanotubes were investigated. Aligned carbon nanotubes with high density and purity were achieved by CVD on mesoporous silica substrate. The Raman scattering of aligned carbon nanotubes was carried out, and the dependence of the phonon properties on the microstructure of the nanotubes has been discussed.     

In-depth profiling,characterization, and comparison of the ginsenosides among three different parts (the root,stem leaf,and flower bud) of Panax quinquefolius L. by ultra-high performance liquid chromatography/quadrupole-Orbitrap mass spectrometry

Analytical and Bioanalytical Chemistry - Despite Panax quinquefolius L. serving as a crucial source for food additives, healthcare products, and herbal medicines, unawareness of the metabolome...     

Nb∶KTiOPO4晶体的生长和倍频性能

通过研究晶体生长工艺参数对Nb∶KTiOPO4(Nb∶KTP)晶体生长的影响,用熔盐顶部籽晶法获得尺寸为55mm×25mm×5mm的Nb∶KTP透明单晶.研究中发现熔体的温度梯度、籽晶和降温速率将严重影响Nb∶KTP晶体的生长.Nb离子的引入不利于Nb∶KTP晶体的生长,尤其是造成晶体易开裂,且沿a轴方向生长速度非常缓慢.同时,Nb的引入大大改变Nb∶KTP晶体的倍频性能.掺杂Nb浓度的摩尔分数为13;时,Nb∶KTP晶体的倍频的Ⅱ型相位匹配的截止波长缩短至937nm,且有效产生469nm倍频蓝光;掺杂Nb浓度的摩尔分数为3;时,Nb∶KTP晶体对Nd∶YAG的1.0642μm激光倍频的最佳相位匹配角为θ=88.32°,()=0°,非常接近90°非临界相位匹配方向.     

单驱动器变形镜对低阶像差补偿能力的研究

变形镜能够实时校正波前相位畸变,减弱大气湍流的影响,是自适应光学系统的核心器件。单驱动器变形镜通过1个驱动器产生1个模式,恢复波前相位。利用有限元软件,研究了单驱动器变形镜对低阶像差的补偿能力。仿真结果表明,单驱动器变形镜可以对离焦、像散及彗差进行有效补偿,通过控制驱动器的位移,分别实现了对PV值为5 m的离焦、像散和慧差的补偿,补偿后的残差PV值分别为1.5 m、1.6 m和1.2 m,残差的RMS值分别为0.99 m、0.63 m和0.59 m。