Fluorescent Characteristics of Rheumatoid Arthritis Patients Blood Lymphocytes

A fluorescent probe, ABM, aminoderivative of benzanthrone, synthesized in the Department of Organic Chemistry of the Riga Technical University (Latvia), has been successfully used to characterize changes in the structural and functional properties of cell membranes during different pathologies. In the present study the physicochemical properties and the functional activity of the peripheral blood mononuclear cells (lymphocytes—Ly) in patients with rheumatoid arthritis (RA) were studied using the ABM probe. Intensity of the ABM fluorescence in the celi suspension, functional activity of the ly anisotropy of the membranes differ patients with different titres of rheumatoid factor in blood. Patients with seropositive RA had decreased proliferative activity and lower number of iy in blood plasma indicating greater alterations of the immunoregulating processes in these patients as compared to patients with seronegative RA. In the latter the Ly deficiency is compensated to some extent by increased proliferation activity of these cells. The ABM fluorescence intensity correlated not only with membrane anisotropy (r = 0.97, but also with the proliferation activity of the Ly (r = 0.98). The above parameters correlated with the clinical manifestations of the disease. The results indicate that the fluorescent probe ABM is useful for screening the physicochemical status of Ly membranes and the proliferation activity of these cells in RA patients.     

Almost Cross-Intersecting and Almost Cross-Sperner Pairs of Families of Sets

For a set G and a family of sets ${\mathcal{F}}$ let ${\mathcal{D}_{\mathcal{F}}(G)=\{F\in \mathcal{F}:F\cap G=\emptyset\}}$ and ${\mathcal{S}_{\mathcal{F}}(G)=\{F\in\mathcal{F}:F\subseteq G\,{\rm or} \,G \subseteq F\}.}$ We say that a family is l-almost intersecting, (≤ l)-almost intersecting, l-almost Sperner, (≤ l)-almost Sperner if ${|\mathcal{D}_{\mathcal{F}}(F)|=l, |\mathcal{D}_{\mathcal{F}}(F)|\le l, |\mathcal{S}_{\mathcal{F}}(F)|=l, |\mathcal{S}_{\mathcal{F}}(F)| \le l}$ (respectively) for all ${F \in \mathcal{F}.}$ We consider the problem of finding the largest possible family for each of the above properties. We also address the analogous generalization of cross-intersecting and cross-Sperner families.     

Asymmetric cyclopropanation reactions catalyzed by carbohydrate-based crown ethers

Optically active cyclopropane derivatives were prepared by a novel, simple and green approach in high enantioselectivities using monosaccharide-based chiral crown ethers as phase transfer catalysts. The crown ethers having d-glucopyranoside, d-mannopyranoside and d-altropyranoside units proved to be efficient catalyst in a few asymmetric phase transfer cyclopropanation reactions. The Michael-initiated ring closure (MIRC) reactions of diethyl bromomalonate with chalcones took place with complete diastereoselectivity and up to 99% ee. Using benzylidenemalononitrile, 2-arylidenemalononitriles, 2-benzylidene-1,3-indandione, substituted 2-benzylidene-1,3-indandiones, 2-arylidene-1,3-indandiones and 2-benzylidene-1,3-diphenyl-1,3-propanediones enantioselectivities up to 92%, 99%, 54% 93%, 89% and 72%, respectively, were achieved, in the presence of chiral lariat ethers derived from different monosaccharides. The absolute configuration of a cyclopropane diester product was determined by a combined CD spectroscopic and theoretical study.     

Mesoporous porphyrinic metal-organic framework nanoparticles/3D nanofibrous scaffold as a versatile platform for bone tumor therapy

Removal of residual tumor cells and regeneration of large bone defects are urgently required after surgical resection of bone tumors. To address these issues, a bifunctional scaffold with high photothermal effect and osteogenesis was developed for bone tumor therapy. Sintered mesoporous imidazolate framework 8 (ZIF8) nanoparticles with porphyrin-like macrocycles were synthesized by calcination of ZIF8 precursors under an N₂ atmosphere. The prepared ZIF8 possesses good photothermal efficacy and drug loading capability. Phenamil (Phe), an activator of bone morphogenetic protein pathways, was encapsulated into ZIF8 before loading onto gelatin nanofibrous (GF) scaffolds. The loaded Phe exhibited sustained and near-infrared triggered release profiles, which is capable of promoting bone morphogenetic protein 2 induced osteogenic differentiation even under near-infrared treatment. Moreover, our studies revealed that the photothermal effect of GF/ZIF8-Phe scaffolds can kill MG-63 cells in vitro and inhibit subcutaneous tumor growth in vivo. Therefore, the GF/ZIF8-Phe scaffold represents a novel bifunctional platform for tumor therapy and bone regeneration.     

分子轨道理论奠基人—罗伯特?桑德森?马利肯

1966年,化学家、物理学家罗伯特·桑德森·马利肯(1896-1986)"因其应用分子轨道理论对化学键和分子电子结构的基础性研究"而获得了诺贝尔化学奖。本文介绍了马利肯的生平经历和科学成就,尤其对其科学探索的过程予以呈现。     

一种可调式恒流源的特性分析

本文对一种含CRD的恒流电路进行了具体的讨论,从而导出电流稳定性参数的基本表示式。文中所作的分析和计算表明:该电路具有输出电流大,稳定性高,结构简单和调节方便等优点。可以期望,它将为恒流源的低温度系数问题提供一种新的解决途径。     

高功率二极管泵浦腔内倍频激光器

 成功研制了一台高功率二极管泵浦声光Q开关腔内倍频Nd:YAG激光器。当泵浦功率约为350W时，采用透过率为30%的输出耦合镜，调Q激光输出功率32.5W，脉宽约200ns，重复频率7kHz；采用Ⅱ类匹配KTP晶体腔内倍频，获得了32.5W的绿光输出，脉宽约120ns。输出光束平滑，远场为类高斯分布，测得的光束质量因子为3.6。     

微波法制备石墨烯及石墨烯基材料的研究进展

石墨烯(Gr)由于其独特的单原子层二维结构及优异的性能,在材料、电子、化学、能源、生物医药等众多领域具有广阔的应用前景,引起了众多学者的研究兴趣。如何高产量获得高质量的Gr对其未来的开发和应用至关重要。微波法是制备Gr的重要方法之一,具有绿色、高效、简便快捷等特点。本文综述了近几年微波法制备Gr、掺杂Gr和Gr基纳米复合材料的研究进展以及后者在锂离子电池负极材料方面的应用,并对其发展方向进行了展望。     

Development of a Joint Hydrogen and Syngas Combustion Mechanism Based on an Optimization Approach

A comprehensive and hierarchical optimization of a joint hydrogen and syngas combustion mechanism has been carried out. The Kéromnès et al. (Combust Flame, 2013, 160, 995–1011) mechanism for syngas combustion was updated with our recently optimized hydrogen combustion mechanism (Varga et al., Proc Combust Inst, 2015, 35, 589–596) and optimized using a comprehensive set of direct and indirect experimental data relevant to hydrogen and syngas combustion. The collection of experimental data consisted of ignition measurements in shock tubes and rapid compression machines, burning velocity measurements, and species profiles measured using shock tubes, flow reactors, and jet‐stirred reactors. The experimental conditions covered wide ranges of temperatures (800–2500 K), pressures (0.5–50 bar), equivalence ratios (? = 0.3–5.0), and C/H ratios (0–3). In total, 48 Arrhenius parameters and 5 third‐body collision efficiency parameters of 18 elementary reactions were optimized using these experimental data. A large number of directly measured rate coefficient values belonging to 15 of the reaction steps were also utilized. The optimization has resulted in a H₂/CO combustion mechanism, which is applicable to a wide range of conditions. Moreover, new recommended rate parameters with their covariance matrix and temperature‐dependent uncertainty ranges of the optimized rate coefficients are provided. The optimized mechanism was compared to 19 recent hydrogen and syngas combustion mechanisms and is shown to provide the best reproduction of the experimental data.     

Reactions of methoxybenzylidene derivatives of 2,2-dimethyl-1,3-dioxane-4,6-dione and their saturated analogs with certain nucleophilic reagents

The reactions of the methoxybenzylidene derivatives of 2,2-dimethyl-1,3-dioxane-4,6-dione and their saturated analogs with potassium hydroxide in methanol, ammonia, and hydrazine hydrate were realized. The 1,2-bis(methoxybenzylidene)hydrazines, amides, and hydrazides of methoxybenzylidene-malonic acid, suitable for use as structural blocks in the synthesis of various structures based on them, were prepared and characterized.