仲胺配合物的合成、晶体结构及与DNA作用的研究

合成了一种新颖三齿配体(L),N-(4-甲基苯)-N’-(2-(4-甲基苯氨基)乙基)乙烷-1,2-二胺,并制备了它的四种过渡金属配合物,结合元素分析、红外、1 HNMR和摩尔电导,确定配合物的组成为[ML(NO3)2](M=CuⅡ,CoⅡ,NiⅡ,ZnⅡ).用X-ray单晶衍射解析了Zn-L和Ni-L的单晶结构.通过紫外、荧光光谱研究了这四种金属配合物与小牛胸腺DNA的相互作用,根据结果推断出配合物与DNA的作用方式可能均为静电结合.Cu-L,Co-L,Ni-L,Zn-L与DNA的结合常数分别为:3.34×104,7.65×103,2.15×104,2.40× 104.     

Polarity formation by a higher order interaction Markov-like chain

Vector property generation is discussed for chain growth by higher order interactions. Because of a deterministic property evolution a state space approach was used. Although not strictly Markovian, the system shows ergodic properties and convergence for a large number of attachment steps. For reasonable interaction energies attributed to increasing order, the main extra contribution to polarity formation results from interactions up to next nearest neighbours. Nonlinear equations up to third order were solved by an iterative procedure.     

Basic training and methodological problems of the modern chemical education in secondary school

The article deals with basic problems of modernization of the education system in our country and the ways of their ra-tional solution. It is shown that among the main objectives are the mass training of highly qualified teachers, and increase of their prestige in society. The authors discuss the content of secon-dary school courses in physics, chemistry and biology, and rele-vant textbooks. Particular attention is drawn to the scientific and methodological support to the chemical education, as well as general standards.     

Flexibility of Na,K-ATPase secondary structure upon drug-protein interaction

The enzyme Na⁺, K⁺-ATPase is an integral membrane protein which transports sodium and potassium cations against an electrochemical gradient. The transport of Na⁺ and K⁺ ions is connected to an oscillation of the enzyme between the two conformational states, the E₁ (Na⁺) and the E₂ (K⁺) conformations. The enzymatic activity of ATPase is largley affected by different ligands complexation. This review reports the effects of several drugs such as AZT (anti-AIDS), cis-Pt (antitumor), aspirin (anti-inflammatory) and vitamin C (antioxidant) on the stability and secondary structure of Na,K-ATPase in vitro. Drug-enzyme binding is mainly through H-bonding to the polypeptide C=O and C-N groups with two binding constants K_1(AZT) = 5.30 × 10⁵ M^?1 and K_2(AZT) = 9.80 × 10³ M^?1 for AZT and one binding constant for K_cis-Pt = 1.93 × 10⁴ M^?1, K_aspirin = 6.45 × 10³ M^?1 and K_ascorbate = 1.04 × 10⁴ M^?1 for cis-Pt, aspirin and ascorbic acid. The enzyme secondary structure was altered from that of α-helix 19.8% (free protein) to almost 22–26% and the β-sheet from 25.6% to 18–22%, upon drug complexation with the order of induced stability AZT > cis-Pt > ascorbate > aspirin.     

Interaction between secondary and higher schools: A basis for fundamental chemical education

Nowadays, within the Russian system of higher education there are two subsystems working fairly independently. One is mass higher education, and other is fundamental (quality) education. The educational reform which has been underway since the mid-1990s only makes worse the situation. Every year higher school teachers note a decrease of the quality of applicants and first-year students, gaps in their knowledge of chemistry, mathematics, and other disciplines. Under such conditions, universities should provide themselves with a corpse of the adequately prepared applicants. What can be done in order to preserve traditions of the Russian fundamental university education? First of all, quality textbooks for school pupils and applicants can be written and published. Further, connections between higher education institutions and secondary school in various regions of the country can be established and developed. Another very important task consists in organizing and conducting science Olympiads for schoolchildren and applicants. All these activities are being undertaken now by the Moscow State University.     

Influence of microenvironment and liposomal formulation on secondary structure and bilayer interaction of lysozyme

The conformation of peptide and protein drugs in various microenvironments and the interaction with drug carriers such as liposomes are of considerable interest. In this study the influence of microenvironments such as pH, salt concentration, and surface charge on the secondary structure of a model protein, lysozyme, either in solution or entrapped in liposomes with various molar ratios of phosphatidylcholine (PC):cholesterol (Chol) was investigated. It was found that entrapment efficiency was more pronounced in negatively charged liposomes than in non-charged liposomes, which was independent of Chol content and pH of hydration medium. The occurrence of aggregation, decrease in zeta potential, and alteration of ³¹P NMR chemical shift of negatively charged lysozyme liposomes compared to blank liposomes suggested that the electrostatic interaction plays a major role in protein–lipid binding. Addition of sodium chloride could impair the neutralizing ability of positively charged lysozyme on negatively charged membrane via chloride counterion binding. Neither lysozyme in various buffer solutions with sodium chloride nor that entrapped in liposomes showed any significant change in their secondary structures. However, significant decrease in α-helical content of lysozyme in non-charged liposomes at higher pH and salt concentrations was discovered.     

Combinatorial chemistry in higher school: Ten-year experience of research,educational, and managerial projects

Key aspects of differences between liquid-phase parallel synthesis and preparation of a single compound at a time are reviewed. Specific technique and equipment is required to make in the parallel manner such processes as heating (involving MW ovens and flow microreactors), extraction, filtration, and chromatography. Rich illustrations may be useful in educational courses on medicinal and combinatorial chemistry.     

影响中学生化学模糊观念改变的因素及其权重分析

学生模糊观念的产生有着根本原因,且影响其变化的因素主要有 5个维度。我们通过层次分析法得到 5个维度的权重值。这 5个维度的权重值分别为:认知方式:021元认知:018　认识论:022　社会环境 /动机 /情感:013本体论:026。     

影响中学生化学模糊观念改变的因素及其权重分析

学生模糊观念的产生有着根本原因，且影响其变化的因素主要有5个维度。我们通过层次分析法得到5个维度的权重值。这5个维度的权重值分别为：认知方式：0．21 元认知0．18 认识论：0．22 社会环境／动机／情感：0．13 本体论：0．26。     

Probing interaction of melittin with lipid membranes using liquid secondary ion mass spectrometry

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The kinetics of the interaction of peroxy radicals. II. Primary and secondary alkyl peroxy

A chain mechanism is proposed to account for the very rapid termination reactions observed between alkyl peroxy radicals containing α-C—H bonds which are from 10⁴ to 10⁶ faster than the termination of tertiary alkyl peroxy radicals. The new mechanism is with termination by . \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R}\overline {{\rm CHOO}} $\end{document} is the zwitterion originally postulated by Criegee to account for the chemistry of O₃-olefin addition. Heats of formation are estimated for \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {{\rm CH}_2 {\rm OO,}} {\rm }\overline {{\rm RCHOO}} $\end{document}, and \documentclass{article}\pagestyle{empty}\begin{document}$ ({\rm C}\overline {{\rm H}_3 )_2 {\rm COO}} $\end{document} and it is shown that all steps in the mechanism are exothermic. The second step can account for (¹Δ)O₂ which has been observed. k₁ is estimated to be 10^9–2/θ liter/M sec where θ = 2.303RT in kcal/mole. The second and third steps constitute a chain termination process where chain length is estimated at from 2 to 10. This mechanism for the first time accounts for minor products such as acid and ROOH found in termination reactions. Trioxide (step 3) is shown to be important below 30°C or in very short time observations (<10 s at 30°C). Solvent effects are also shown to be compatible with the new mechanism.     

Accelerated ring-opening metathesis polymerization of a secondary amide of 1-cyclobutene by hydrogen-bonding interaction

A hydrogen-bond-assisted model is proposed for ring-opening metathesis polymerization (ROMP) of a secondary amide of 1-cyclobutene, resulting in the fastest reaction rate in a nonpolar solvent, toluene. This new model was supported by the investigation on how the solvent effect affected the NMR spectra, ROMP kinetic studies, and the copolymerization of monomers 1 and 2.     

Natural-sciences education in secondary school in the USSR and Russia: History, trends, and challenges of modernization

Changes in teaching natural sciences (physics, chemistry, and biology) and mathematics in secondary school in the USSR at different times and in post-Soviet era were analyzed. The trends of these changes were discussed and analyzed. The results of passing the Unified State Examination in these classroom disciplines in recent years, as well as the results shown by Russian secondary school learners in the Program for International Student Assessment in 2000, 2003, 2006, and 2009 were discussed. A conclusion was made that teaching natural sciences is deteriorating year after year. The causes of this phenomenon were analyzed, and measures to improve the training of secondary school learners on these subjects were proposed.     

Problems in applying secondary reactions to the activation analysis of semiconductor surface layers

Investigations have been made concerning the determination of special contaminants (e.g. oxygen, boron) in the surface layers or epitaxially grown layers of semi-conductor crystals. These contaminants are insensitive to the conventional (n, γ) analysis and for their activation charged particles (e.g. t, α) from nuclear reactions induced by the capture of reactor neutrons are used. The specific particle yield from such reactions, e.g.⁶Li(n,t)α, was studied. The optimum conditions for the producing of activating layers (containing Li) and their optimum contact with the sample under investigation are discussed. Considering the so-called activation depth, a method was developed for the appropriate removal of the activated layer and the elements to be determined are subsequently separated from the semiconductor matrix by a fast chemical procedure. The combined activation cross sections measured on standard samples are given for different compositions and species of activating layers.     

Multireference configuration interaction studies on higher valence and Rydberg states of OClO, ionization potentials, and electron detachment energies

MRCI results are reported for the vertical excitation energies (VEE) and oscillator strengths f of doublet states of OClO up to 11 eV, including 3b(1) → 4s, 4p, 3d, 5s, 5p, 4d, and most 1a(2), 8a(1), 5b(2) → 4s and 4p Rydberg states. The lowest Rydberg states 3b(1) → 4s and 3b(1) → 4p(x) have mixed valence-Rydberg character. The observed spectral bands were reassigned to include valence states which have generally higher oscillator strengths. The well-known valence state 1(2)A(2) has a VEE of 3.63 eV, and a relatively high f of 0.042. Overall, the calculated oscillator strengths are in good agreement with measured values. The lowest quartet state, 1(4)B(2), lies at 6.95 eV. Quartet Rydberg states start with 1a(2) → 4s at 9.28 eV. According to calculated vertical ionization potentials (VIP) of OClO, the second VIP at 12.59 eV is reassigned from 1(3)B(1) to 1(3)B(2) (ionization from 1a(2), rather than 8a(1)), and the third VIP at 12.63 eV from 1(1)B(1) to 1(3)B(1) (ionization from 8a(1)). Vertical electron detachment energies of OClO(-) have been calculated up to 8.9 eV. There is good agreement with experimental values.     

The interaction of hydrogen and ammonia plasmas with polymethacrylic esters,studied by static secondary ions mass spectrometry

The interactions of H₂ and NH₃ plasmas with the surfaces of various poly(alkylmethacrylate)s and of poly(phenylmethacrylate) have been studied with XPS and SSIMS. Experiments on poly(methylmethacrylate) reveal that during short treatment times with the NH₃ plasma chain, scission takes place and nitrogen is not incorporated into the surface. The chain scission also takes place with the H₂ plasma. With the aid of SSIMS results, the nature of the chain scission could be deduced. Comparison of these results with those on poly(n-butylmethacrylate) and poly(t-butylmethacrylate) reveals a reaction mechanism in which hydrogen atoms generated in both plasmas play an important role in the chain scission process. After longer treatment time with the NH₃ plasma, the poly(methylmethacrylate) surface becomes deoxygenated and nitrogen is incorporated into surface structures of low molecular weight. Experiments on poly(phenylmethacrylate) reveal that already during short treatment times with the NH₃ plasma, nitrogen is incorporated into the aromatic ring. Chain scission does not play an important role. One of the processes with the H₂ plasma is hydrogenation of the aromatic ring, leading to poly(cyclohexylmethacrylate).     

Specific interaction between fluorine atoms and thiol groups accounting for higher domain purity and photostability in narrowband BHJ systems

In order to explore the role of fluorine atoms on photostability as well as morphology control of active layer in the presence of 1,4‐butanedithiol (BT), the four polymers with or without fluorine atoms in the backbones including polythieno[3,4‐b]thiophene/benzodithiophene, poly[(4,8‐bis‐(2‐ethylhexyloxy)‐benzo(1,2‐b:4,5‐b9)dithiophene)‐2,6‐diyl‐alt‐(4‐(2‐ethylhexanoyl)‐thieno[3,4‐b]thiophene‐)‐2‐6‐diyl)], poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)], and poly[4,8‐bis‐(2‐ethyl‐hexyl‐thiophene‐5‐yl)‐benzo[1,2‐b:4,5‐b0]dithiophene‐2,6‐diyl]‐alt‐[2‐(20‐ethyl‐hexanoyl)‐thieno [3,4‐b]thiophen‐4,6‐diyl] were selected for comparison. It is found that the specimens containing fluorine atoms in polymer backbones showed of higher stability after illumination for 1 h in the presence of BT additive, contributing to the higher domain purity. The specific interaction between fluorine atoms and thiol groups was demonstrated by the appearance of novel absorption peak at 2663.1 cm^?1, in addition to the broadening of peak at 2556.2 cm^?1 ascribing to S? H stretching vibration as confirmed by Fourier transform infrared (FTIR) spectroscopy. The finding may guide the accurate use of thiols as effective solvent additive in morphology and stability optimization. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 941–951     

Effect of secondary MO interaction on the regiospecificity in the reactions of tf-ionones with singlet oxygen

The ene reactions of a-ionones with singlet oxygen were examined to ascertain the effect of secondary MO interaction between the reactants on the reaction regiospecificity. Exclusive formation of 3-hydroxy-V-ionones found in the reactions reveals favorable interaction of singlet oxygen with the acyclic fl-hydrogen atom. On the other hand, no formation of 3-hydroxy-0-ionones implies that the steric requirement was not met for the bond formation between zwitterionic perepoxide with Ci-hydrogen in the process. The MMP21 and MNDO calculations indicate minus value of the secondary interaction energy for the acyclic a-hydrogen abstraction and a repulsion between the oxygen with C₁-hydrogen atom. Twisting tilting of the double bond may account for favorable attack of singlet oxygen on C3. An explanation of the excellent regiospecificity was addressed and placed in proper mechanic prospective.