Interactions Between Ozone,Halogens and Organic Compounds

During drinking-water treatment, ozone used as a preoxidant and chlorine required for final disinfection, lead to competing chemical reactions, in the case of raw water containing both organic compounds and inorganic salts (such as bromides and ammonia).

The study of the interactions between those reactants has been made according to the following main topics :

As for THM formation, experiments conducted on simple organic compounds or on natural fulvic acids show important decreases in THM or TCAA formation after ozonation. It may be noticed, however, that the ozonation of surface waters may induce the formation of haloform precursors, usually with a low level of reactivity.

In water supplies containing bromide ions, oxidation of the latter through hypobromous acid may take place during the ozonation stage. Failing preozonation treatment, hypobromous acid is generated very rapidly during chlorination, thus inducing the formation of chloro- brominated organic compounds.

During the ozonation of fulvic acid solutions, the presence of small amounts of bicarbonate was found to improve precursor removal significantly.

It can be concluded that the partial analogy of the action of ozone or chlorine on aromatic structures, whether simple or complex (such as humic and fulvic acids), seems to indicate that the consequence of preozonation is the destruction, at least in part, of the most reactive sites for THM production, thus leading to a decrease of the volatile organochlorinated compounds formed during the post-chlorination. However, some ozonation products of natural waters are THM precursors, though of low reactivity. Then, in the presence of bromide ions, the formation of volatile organobrominated compounds may be observed during ozonation.     

金属化合物在HDPE膨胀阻燃体系中的协同作用研究

研究了几种金属化合物对HDPE膨胀阻燃体系(IFR)的协同作用,通过极限氧指数（LOI）、DSC—TG、SEM对复合材料的阻燃、热稳定性和成炭情况进行研究,分析了金属化合物与膨胀阻燃剂协效作用机理。LOI测试显示：当ZEO、ZnO、Al2O3添加量分别为3%（质量百分比,下同）、1%、3%时,极限氧指数达到29.6%、29.0%、29.4%,比单独添加IFR分别高出4.6、4.0和4.4个百分点;DSC-TG和SEM结果表明：ZEO、ZnO、Al2O3主要通过促进PE-HD/IFR体系凝聚相快速成炭,稳定炭层强度来发挥其协效作用,而对最终成炭量贡献不大。     

Probing of Interactions of Magnetite Nanoparticles Coated with Native and Aminated Starch with a DPPC Model Membrane

Understanding the mechanism of interactions between magnetite nanoparticles and phospholipids that form cellular membranes at the molecular level is of crucial importance for their safe and effective application in medicine (e.g., magnetic resonance imaging, targeted drug delivery, and hyperthermia-based anticancer therapy). In these interactions, their surface coating plays a crucial role because even a small modification to its structure can cause significant changes to the behaviour of the magnetite nanoparticles that come in contact with a biomembrane. In this work, the influence of the magnetite nanoparticles functionalized with native and aminated starch on the thermodynamics, morphology, and dilatational elasticity of the model cell membranes was studied. The model cell membranes constituted the Langmuir monolayers formed at the air–water interface of dipalmitoylphosphatidylcholine (DPPC). The surface of the aminated starch-coated nanoparticles was enriched in highly reactive amino groups, which allowed more effective binding of drugs and biomolecules suitable for specific nano–bio applications. The studies indicated that the presence of these groups also reduced to some extent the disruptive effect of the magnetite nanoparticles on the model membranes and improved their adsorption.     

Modeling Synergistic and Antagonistic Interactions in Xenobiotic Compounds

Over time, synergistic/antagonistic interactions between pairs of compounds has been examined from a variety of viewpoints that impose difficulties in comparative studies. The increasing importance of potentiated activity in plant–organism interfaces mediated by secondary phytometabolites and also of inter- and intraspecific animal interactions, and their ecological impact in terms of increased cost effectiveness and organism fittness in the production of active compounds, demands that a standard methodology be designed to ascertain the amount of synergism/antagonism of A + [B, C, ..., Z] mixtures. Here we preface one such method, based on the comparison of theoretically predicted addition of dose–response (D/R) curves of pairs of compounds mixed in 0–100% relative proportions and constant added dosage, examined at various total dosages, with experimental results of similarly composed mixtures. It is shown that large effects in the activity prediction curves occur as a consequence of minor changes in the D/R profiles of individual compounds. These changes may lead to equivocal assessment of potentiation by application of coactivity coefficients without close examination of predicted curves. Evaluation of this method with literature from the data surveyed illustrated its potentially general application in studies of compound synergism.     

Infrared Spectroscopy of Interphases Between Model Rubber Compounds and Plasma Polymerized Acetylene Films

Thin (～ 750 Å) plasma polymerized films of acetylene deposited onto polished steel substrates are promising primers for rubber-to-metal bonding. The as-deposited films contained mono- and di-substituted acetylene groups, aromatic groups, and groups such as carbonyl which apparently resulted from reaction of residual free radicals with oxygen when the films were exposed to the atmosphere. There was some evidence for formation of acetylides in the interphase between the films and the substrates. Reactions occurring in the interphase between the plasma polymerized films and natural rubber were simulated using a model “rubber” consisting of a mixture of squalene, zinc oxide, carbon black, sulfur, stearic acid, diaryl-p-diphenyleneamine, and N, N-dicyclohexyl-benzothiazole sulfenamide (DCBS). It was found that zinc oxide reacted with stearic acid to form zinc stearate in the interphase between squalene and the plasma polymerized acetylene primer. Zinc stearate reacted with DCBS and sulfur to form an accelerator complex and zinc perthiomercaptides. The perthiomercaptides reacted with squalene and the plasma polymer to form pendant groups which eventually reacted to form crosslinks between squalene and the primer. In the absence of cobalt naphthenate, the formation of pendant groups and eventually crosslinks was relatively slow and the length of the sulfur chains in the crosslinks and the pendant groups was relatively long. When cobalt naphthenate was added to the model “rubber,” the reactions in the interphase between squalene and the plasma polymerized film occurred much faster and the length of the crosslinks and the pendant groups was much shorter.     

TLC Separation of Glucopyranosyl Sinapate and Other Phenolic Compounds from Rapeseed

Glucopyranosyl sinapate was obtained from rapeseeds using column chromatography on Sephadex LH-20 and RP-18 semipreparative HPLC. TLC analysis of this compound, sinapic acid and phenolic compounds fractions from column chromatography were conducted on plates coated with silica gel (standard and HPTLC), with cellulose and on RP-TLC plates. Eleven various solvent systems were applied to develop chromatograms. HPTL plates were found more efficient than those coated with standard silica gel. Compared to the latter cellulose ensured worse results of TLC analysis. The best developing system for plates coated with silica gel was benzene-methanol-acetic acid (90:16:8). Separation of the compounds analysed using RP-TLC depended on octadodecylsilanization degree of silica gel on TLC plate.     

The Content of Sulphur Compounds in Solvent Extraction Products of Winter Type Low and High Glucosinolate Rapeseed

Commercially processed seeds and solvent extraction products of low and high glucosinolate rapeseed were analysed from the point of view of sulphur distribution. Glucosinolate and sulphur content were analysed in seeds, while in oils, miscellas and solvents of both varieties sulphur content were determined by tow - the Raney nickel and combustion - procedures. In comparison to traditional rapeseed variety, commercially processed seeds of winter double zero variety contain about 60–70% less of glucosinolates and only 40% less of sulphur. Such a reduction allows to reduce the level of sulphur in double zero rapeseed oil of about 50%.     

Intermolecular Interactions in Crystal Structures of Imatinib-Containing Compounds

Imatinib, one of the most used therapeutic agents to treat leukemia, is an inhibitor that specifically blocks the activity of tyrosine kinases. The molecule of imatinib is flexible and contains several functional groups able to take part in H-bonding and hydrophobic interactions. Analysis of molecular conformations for this drug was carried out using density functional theory calculations of rotation potentials along single bonds and by analyzing crystal structures of imatinib-containing compounds taken from the Cambridge Structural Database and the Protein Data Bank. Rotation along the N-C bond in the region of the amide group was found to be the reason for two relatively stable molecular conformations, an extended and a folded one. The role of various types of intermolecular interactions in stabilization of the particular molecular conformation was studied in terms of (i) the likelihood of H-bond formation, and (ii) their contribution to the Voronoi molecular surface. It is shown that experimentally observed hydrogen bonds are in accord with the likelihood of their formation. The number of H-bonds in ligand-receptor complexes surpasses that in imatinib salts due to the large number of donors and acceptors of H-bonding within the binding pocket of tyrosine kinases. Contribution of hydrophilic intermolecular interactions to the Voronoi molecular surface is similar for both conformations, while π...π stacking is more typical for the folded conformation of imatinib.     

低温微波辐射对脂肪氧合酶催化体系的影响

文章主要考察了微波辐射对脂肪氧合酶的活性和催化亚油酸(钠)反应产率的影响。实验结果表明,低功率(10~60 w)微波辐射对脂肪氧合酶酶活影响不大,100 w时会导致酶活损失接近50%。在60 w时,微波辐射时间的延长会引起酶活的降低。将微波辐射应用于催化亚油酸(钠)体系时,发现微波技术并不能增强脂肪氧合酶与底物的结合,且对体系传质效果影响也不大。     

Interactions Between an Anionic Fluorosurfactant and a PEO-PPO-PEO Triblock Copolymer in Aqueous Solutions

Surface tensions were determined for a mixture of an anionic fluorinated surfactant and a PEO-PPO-PEO triblock copolymer. The interactions between the two surfactant molecules in the mixed monolayer and the mixed micelle were studied through molecular interaction parameters (β ^σ, β ^M) and the molecule exchange energy (ε, ε _m). It was noted that synergism and strong attractive interactions took place between the anionic fluorinated surfactant and the triblock copolymer molecules in both mixed micelles and mixed monolayers, reflected by the interaction parameter values of between −10 and −18 for all mixtures investigated. Moreover, it can be seen from the value of (ε − ε _m) that when the mixture has a small amount of triblock copolymer, the formation of mixed micelle results in a greater decrease in energy than does the formation of a mixed monolayer. With an increase in the mole fraction of the triblock copolymer in the mixture, in order to obtain the lowest surface energy, surfactants tend to form mixed monolayers first, and then form mixed micelles.     

Physical Interactions Between Molecules and Supported Catalysts

Analytic expressions for the interaction potential of a molecule with a supported catalyst are obtained. Particular attention is focused on the region of the boundary line between the metal particle and the substrate.     

高聚物中纳米填料与无卤阻燃剂间的相互作用

根据新近发表的文献,综述环氧树脂/间苯二酚双(二苯基磷酸酯)/蒙脱石(EP/RDP/MMT),聚苯乙烯(PS)/芳香族磷酸酯(ArP)/MMT,乙烯-乙酸乙烯共聚物(EVA)/氢氧化物(MH)/MMT及聚苯乙烯/间苯二酚四苯基双磷酸酯/碳钠米管(PS/RDP/CNT)四个系统中纳米填料与无卤阻燃剂的相互作用。结果表明,除EP/RDP/MMT系统在阻燃性上可能有一定的对抗作用外,其他系统在热稳定性及阻燃性上均有一定的协效作用。     

Interactions Between Cement Minerals and Hydroxycarboxylic-Acid Retarders: I, Apparent Adsorption of Salicylic Acid on Cement and Hydrated Cement Compounds

A radioisotope assay method was developed to measure the apparent adsorption of salicylic acid on cement and hydrated cement compounds at concentrations of salicylic acid in aqueous solution up to 0.2 wt%, thus including the range of concentrations used for hydroxycarboxylic-acid retarders in concrete. Previously published data were available only for concentrations below 0.01%. The results confirm that there is only limited apparent adsorption on dicalcium and tricalcium silicates, whereas apparent adsorption on paste- and bottle-hydrated products of these compounds is significant. Apparent adsorption on tricalcium aluminate is strong and is greater at intermediate concentrations than near saturation. A similar pattern was observed for apparent adsorption on "C₄AF," but the amounts removed from solution were much less. Experiments with C₄AH₁₃, C₃AH₀, and ettringite revealed that hydrated calcium aluminate and aluminate sulfate compounds also remove major amounts of salicylic acid from solution.     

Frustrated Interfaces Facilitate Dynamic Interactions between Native Client Proteins and Holdase Chaperones

Molecular chaperones are crucial for cellular life to ensure that all proteins obtain their right fold and functionality. Many chaperones promiscuously bind a wide spectrum of client proteins, ranging from nascent to quasi-native and native proteins. Several recent studies have investigated, at atomic resolution, how chaperones interact with native proteins. Native proteins feature a wide variety of structural conformations, and therefore, a given chaperone cannot accomplish full surface complementarity to all of its client proteins. This limitation is circumvented by the recognition of frustrated regions on the client protein surface by the chaperone. In this interaction mode, the chaperone forms a multitude of transient local interactions with some segments of the client, whereas other parts are transiently not in favorable interactions. A permanent rearrangement of the client conformation on the chaperone occurs. Reconfiguration on the chaperone surface also gives the client a chance to fold into its correct, minimally frustrated conformation.     

Separation and Purification of Indole in Model Coal Tar Fraction of 9 Compounds System

Separation and purification of indole present in model coal tar fraction was examined by the combination of extraction to separate indole from the crude model coal tar fraction, distillation to obtain high concentration of indole in the extract, and solute crystallization (SC) to obtain high-purity indole present in indole-enriched distillate. The model fraction was made up of four types of nitrogen heterocyclic compounds (quinoline, iso-quinoline, 4.66% indole, and quinaldine), three types of bicyclic aromatic compounds (1-methylnaphthalene, 2-methylnaphthalene, and dimethylnaphthalene), biphenyl, and phenyl ether. Aqueous solutions of formamide and n-hexane were used as the extraction solvent and the SC solvent, respectively. Through the combination of formamide extraction, distillation, and SC using n-hexane in this work, 99.5% indole was recovered. We confirmed that the combination examined by this work was one of the very useful combinations for the high-purity purification of indole present in the coal tar fraction.     

垂直气固两相流动系统中颗粒群与气流之间的相互作用

本文对垂直气固两相流动系统中,从初始流态化到气力输送的整个区域内气固两相之间的相互作用规律进行了研究.结果表明,采用气体与颗粒群之间的曳力系数可以定量表征两者之间的能量交换过程.文章并讨论了不同操作条件下气固曳力系数的变化规律,并由此可见两相流系统中出现的不均匀状态(低气速时产生气泡,高气速时颗粒趋于聚集)均可用体系为使气流对颗粒群做功最小而采取的运动形态来解释.     

Essential-Oil-Mediated Interactions Between Oregano Plants and Helicidae Grazers

Aromatic plants dominate in Mediterranean-type ecosystems. They often produce remarkable quantities of essential oils containing high amounts of phenolic isoprenoids, such as thymol and carvacrol. The purpose of this work was to examine the interactions between commonly occurring aromatic plants in the Mediterranean environment and their snail grazers. The aromatic plants used were two Origanum vulgare subspecies, subsp. hirtum and subsp. vulgare. They differ in the content and the qualitative composition of their essential oil; subsp. hirtum contains a much larger amount and is rich in phenolic compounds. Their effect on the foraging behavior of three snail species, native in Greece, was studied; the snail species were Helix lucorum, H. aspersa, and Eobania vermiculata. The snails' responses to different food sources, raw or processed, with or without essential oils, were evaluated during the different stages of the foraging cycle. During the encounter stage, snails were more repelled than attracted when close to phenol-rich foods. During the acceptance stage, all snail species tended to reject food types that contained high concentrations of subsp. hirtum essential oil. At the feeding stage, subsp. hirtum essential oil caused reduction of daily consumption rates. Overall, the essential oil of O. vulgare subsp. vulgare did not produce any marked change in the snails' behavior. In contrast, that of O. vulgare subsp. hirtum had a repellent effect, particularly when present in naturally occurring high concentrations. Among the snail species, H. lucorum, which does not share the same biotope with O. vulgare subsp. hirtum, was the least tolerant to its essential oil.     

Volatile Mediated Interactions Between Bacteria and Fungi in the Soil

Soil is one of the major habitats of bacteria and fungi. In this arena their interactions are part of a communication network that keeps microhabitats in balance. Prominent mediator molecules of these inter- and intraorganismic relationships are inorganic and organic microbial volatile compounds (mVOCs). In this review the state of the art regarding the wealth of mVOC emission is presented. To date, ca. 300 bacteria and fungi were described as VOC producers and approximately 800 mVOCs were compiled in DOVE-MO (database of volatiles emitted by microorganisms). Furthermore, this paper summarizes morphological and phenotypical alterations and reactions that occur in the organisms due to the presence of mVOCs. These effects might provide clues for elucidating the biological and ecological significance of mVOC emissions and will help to unravel the entirety of belowground' volatile-wired' interactions.