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41.
Bis(tert-butylperoxy)iodobenzene, generated in situ by the reaction between diacetoxyl iodobenzene (DIB) and tert-butyl hydroperoxide (TBHP), was used in the oxidative transformation of primary azides to nitriles, and secondary azides to ketones. 相似文献
42.
Dysfunction of the blood–brain barrier (BBB) is involved in the pathogenesis of many cerebral diseases. Oxidative stress and inflammation are contributing factors for BBB injury. Piceatannol, a natural ingredient found in various plants, such as grapes, white tea, and passion fruit, plays an important role in antioxidant and anti-inflammatory responses. In this study, we examined the protective effects of piceatannol on lipopolysaccharide (LPS) insult in mouse brain endothelial cell line (bEnd.3) cells and the underlying mechanisms. The results showed that piceatannol mitigated the upregulated expression of adhesion molecules (ICAM-1 and VCAM-1) and iNOS in LPS-treated bEnd.3 cells. Moreover, piceatannol prevented the generation of reactive oxygen species in bEnd.3 cells stimulated with LPS. Mechanism investigations suggested that piceatannol inhibited NF-κB and MAPK activation. Taken together, these observations suggest that piceatannol reduces inflammation and oxidative stress through inactivating the NF-κB and MAPK signaling pathways on cerebral endothelial cells in vitro. 相似文献
43.
Wei Liu Kaiwu He Desheng Wu Li Zhou Guowei Li Zequn Lin Xifei Yang Jianjun Liu Maggie Pui Man Hoi 《Molecules (Basel, Switzerland)》2022,27(4)
Discovering new and effective drugs for the treatment of Alzheimer’s disease (AD) is a major clinical challenge. This study focuses on chemical modulation of the gut microbiome in an established murine AD model. We used the 16S rDNA sequencing technique to investigate the effect of xanthohumol (Xn) on the diversity of intestinal microflora in 2-month- and 6-month-old APP/PS1 mice, respectively. APP/PS1 and wild-type mice were treated by gavage with corn oil with or without Xn every other day for 90 days. Prior to and following treatment, animals were tested for spatial learning, cognitive and memory function. We found Xn reduced cognitive dysfunction in APP/PS1 mice and significantly regulated the composition and abundance of gut microbiota both in prevention experiments (with younger mice) and therapeutic experiments (with older mice). Differential microflora Gammaproteobacteria were significantly enriched in APP/PS1 mice treated with Xn. Nodosilineaceae and Rikenellaceae may be the specific microflora modulated by Xn. The penicillin and cephalosporin biosynthesis pathway and the atrazine degradation pathway may be the principal modulation pathways. Taken together, oral treatment with Xn may have a neuroprotective role by regulating the composition of intestinal microflora, a result that contributes to the scientific basis for a novel prophylactic and therapeutic approach to AD. 相似文献
44.
采用多参考组态相互作用(MRCI)方法,结合aug-cc-pV6Z(AV6Z)基组,计算了C2+(X4Σg-,14Σu+)的势能曲线,计算过程中考虑了Davidson修正和相对论效应,并将结果外推至完备基组(CBS)的极限.基于得到的单点能量,用最小二乘法方法进行了Murrell-Sorbie函数拟合,得到了势能函数解析式(APEF).基于APEF,计算了C2+(X4Σg-,14Σu+)离子体系的离解能De,平衡核间距Re,光谱常数ωe,ωeχe,Be,αe,结果与实验和其他理论计算值符合... 相似文献
45.
由微分测量探头和积分器构成的微分积分测量系统广泛应用于脉冲电压和电流测量。依据无源RC积分器的等效电路,分析了在多脉冲信号测量中,无源RC积分器在实现微分信号的积分还原时,可以引起信号的平顶降和信号基线偏离,给出了平顶降和基线偏离与信号脉冲宽度和积分常数的定量关系,计算了在不同积分器参数和脉冲信号参数时的平顶降和基线偏离结果,并且与PSpice电路模拟结果进行了比较,两种结果一致。按照此定量关系,可以根据脉冲信号特点和测量要求,准确确定积分器参数。 相似文献
46.
Vladimir N. Chernega Olga V. Man’ko Vladimir I. Man’ko 《Journal of Russian Laser Research》2017,38(2):141-149
We map the density matrix of the qubit (spin-1/2) state associated with the Bloch sphere and given in the tomographic probability representation onto vertices of a triangle determining Triada of Malevich’s squares. The three triangle vertices are located on three sides of another equilateral triangle with the sides equal to\( \sqrt{2} \). We demonstrate that the triangle vertices are in one-to-one correspondence with the points inside the Bloch sphere and show that the uncertainty relation for the three probabilities of spin projections +1/2 onto three orthogonal directions has the bound determined by the triangle area introduced. This bound is related to the sum of three Malevich’s square areas where the squares have sides coinciding with the sides of the triangle. We express any evolution of the qubit state as the motion of the three vertices of the triangle introduced and interpret the gates of qubit states as the semigroup symmetry of the Triada of Malevich’s squares. In view of the dynamical semigroup of the qubit-state evolution, we constructed nonlinear representation of the group U(2). 相似文献
47.
A full ligand-field energy matrix diagonalization treatment for 3d 1 ions in tetragonal symmetry is developed on the basis of the two spin?Corbit coupling parameter model, and the contributions of the spin?Corbit coupling of the ligand ions to the optical and electron paramagnetic resonance spectra are included. Spin Hamiltonian parameters of the tetragonal ${\rm V}^{4+}$ center in $\hbox{K}_2\hbox{SO}_4 {-} \hbox{Na}_2\hbox{SO}_4{-}\hbox{ZnSO}_4$ glass are calculated from the complete energy matrix diagonalization and the perturbation theory methods. The results calculated by both methods are not only close to each other but also in good agreement with the experimental values. Furthermore, the compressed defect structure of the ${\rm (VO_6)^{8-}}$ cluster is discussed. 相似文献
48.
49.
J. -E. Augustin G. Cosme F. Couchot B. Dudelzak F. Fulda B. Grelaud G. Grosdidier B. Jean-Marie S. Jullian D. Lalanne V. Lepeltier B. Louis F. Mané C. Paulot R. Riskalla Ph. Roy F. Rumpf G. Szklarz Z. Ajaltouni A. Falvard J. Jousset B. Michel J. C. Montret R. Baldini S. Calcaterra G. Capon D. Bisello G. Busetto S. Limentani M. Nigro L. Pescara M. Posocco P. Sartori L. Stanco DM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,36(3):369-376
The radiative decayJ/ψ → γ π+ π? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe +e? storage rings at Orsay. The π+ π? mass spectrum shows a cleanf 2 (1270) signal, and the possible presence of two other states at thef 2 (1720) andf 4 (2030) masses. For thef 2 (1270), the branching ratio BR(J/ψ →γf)xBR(f→π+ π?) is measured to be (7.50±0.30±1.12)×10?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed. 相似文献
50.