Kinds Of Reactions Research Articles

UV-Aging Resistance of Packaging Waste PE Modified Asphalts

The recycled packaging waste PE was adopted to modify the asphalt and the UV-aging resistance of the modified asphalt was studied through the UV-aging experiment. The results showed that the changing trends of softening point aging index, penetration aging index, elastic recovery aging index and viscosity aging index at 135°C of the modified and unmodified asphalt are similar. FTIR analysis and the microscopic structure of the asphalt indicated that there existed two kinds of reactions taking place in the aging process of packing waste PE modified asphalt, the oxidation of raw asphalt and the aging of the polymer.

Density Functional Theory Study of the Reactivities of Perimidine-Based Carbene Analogues of the Group 14 Elements

The potential energy surfaces for the chemical reactions of group 14 carbenes have been studied using density functional theory (B3LYP/LANL2DZ). Five group 14 carbene species containing three six-membered rings, perimidine-E, where E = C, Si, Ge, Sn, and Pb, have been chosen as model reactants in this work. Also, four kinds of chemical reaction, C−H bond insertion, alkene cycloaddition, O−H bond insertion, and dimerization, have been used to study the chemical reactivities of these group 14 carbenoids. The present theoretical investigations suggest that the relative carbenic reactivity decreases in the order C > Si > Ge > Sn > Pb. That is, the heavier the group 14 atom (E), the less reactive are its carbene compounds with respect to chemical reaction. Also, our theoretical findings suggest that all the perimidine-E carbenes are isolable at room temperature, since they are quite inert to chemical reactions, except for reaction with water. Furthermore, the group 14 carbene singlet−triplet energy splitting, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict their reactivities. The results obtained allow a number of predictions to be made.

Single-Electron-Transfer Nitroxide-Radical-Coupling Reaction at Ambient Temperature: Application in the Synthesis of Block Copolymers

Single-Electron-Transfer Nitroxide-Radical-Coupling Reaction at Ambient Temperature: Application in the Synthesis of Block Copolymers

Two kinds of gravitational ejector refrigerator stimulation

Temperatures and levels of refrigerant in the heat exchangers of a gravitational ejector refrigerant make a combined system of numerous mutual couplings. It has some significant properties of self-regulation. There are three kinds of reaction on the self-regulation system of the refrigerator: thermal-type when it is stimulated by changing the temperature of exchangers surrounding, ejector-type stimulated by changing the ejector’s geometry or refrigerant kind, volume-type stimulated by changing the amount of refrigerant. The predicting of a specific reaction of a system balance is difficult but it may be obtained by a mathematical model and calculating experiments.

3-Hydroxypropionyl-Coenzyme A Dehydratase and Acryloyl-Coenzyme A Reductase, Enzymes of the Autotrophic 3-Hydroxypropionate/4-Hydroxybutyrate Cycle in the Sulfolobales

A 3-hydroxypropionate/4-hydroxybutyrate cycle operates in autotrophic CO(2) fixation in various Crenarchaea, as studied in some detail in Metallosphaera sedula. This cycle and the autotrophic 3-hydroxypropionate cycle in Chloroflexus aurantiacus have in common the conversion of acetyl-coenzyme A (CoA) and two bicarbonates via 3-hydroxypropionate to succinyl-CoA. Both cycles require the reductive conversion of 3-hydroxypropionate to propionyl-CoA. In M. sedula the reaction sequence is catalyzed by three enzymes. The first enzyme, 3-hydroxypropionyl-CoA synthetase, catalyzes the CoA- and MgATP-dependent formation of 3-hydroxypropionyl-CoA. The next two enzymes were purified from M. sedula or Sulfolobus tokodaii and studied. 3-Hydroxypropionyl-CoA dehydratase, a member of the enoyl-CoA hydratase family, eliminates water from 3-hydroxypropionyl-CoA to form acryloyl-CoA. Acryloyl-CoA reductase, a member of the zinc-containing alcohol dehydrogenase family, reduces acryloyl-CoA with NADPH to propionyl-CoA. Genes highly similar to the Metallosphaera CoA synthetase, dehydratase, and reductase genes were found in autotrophic members of the Sulfolobales. The encoded enzymes are only distantly related to the respective three enzyme domains of propionyl-CoA synthase from C. aurantiacus, where this trifunctional enzyme catalyzes all three reactions. This indicates that the autotrophic carbon fixation cycles in Chloroflexus and in the Sulfolobales evolved independently and that different genes/enzymes have been recruited in the two lineages that catalyze the same kinds of reactions.

Aroma‐active compounds of Beijing roast duck

AbstractThe aroma‐active compounds of Beijing roast duck were investigated by using aroma extract dilution analysis (AEDA), dynamic headspace dilution analysis (DHDA), gas chromatography–olfactometry–mass spectrometry (GC–O–MS) and odour activity values (OAVs; ratio of concentration to odour threshold). The following volatile components are the predominant odorants of Beijing roast duck: 3‐methylbutanal, hexanal, dimethyl trisulphide, methional, 2‐methylbutanal, octanal, heptanal, 2‐methyl‐3‐furanthiol, 2‐furfurylthiol, 2‐ethyl‐3,5‐dimethylpyrazine, (E,E)‐2,4‐nonadienal, 1‐octen‐3‐ol, nonanal, decanal, (E)‐2‐decenal, (E,E)‐2,4‐decadienal, (E)‐2‐nonenal, (E,Z)‐2,6‐nonadienal, (E,E)‐2,4‐octadienal (fatty, fried), etc. Due to abundant flavour precursors of Beijing crammed duck (raw material of Beijing roast duck), such as amino acids, esters, vitamins and carbohydrates, and the special process (e.g. roasting, drying, etc.), the identified compounds above were likely derived from different kinds of reactions, such as degradation of fatty acids and amino acids, Maillard/Strecker and other associated reactions, which were considered to account for the typical aroma of Beijing roast duck. Copyright © 2009 John Wiley & Sons, Ltd.

Temperature-Sensitive Simultaneous Interpenetrating Polymeric Networks With Improved Mechanical Properties and Shrinking Kinetics

In this study, a new IPN structure was designed and a simultaneous method was for the first time utilized to prepare temperature sensitive PNIPAAm IPN hydrogels by carrying out the radical polymerization and hydrolysis/condensation for two kinds of reaction at the same time. Due to the specific structures, the newly prepared simultaneous IPN gels displayed higher elastic modulus and faster shrinking rates than the conventional PNIPAAm gel.

Intracellular Lectins Involved in Folding and Transport in the Endoplasmic Reticulum

Glycosylation is a highly sophisticated post-translational modification of proteins that occurs in the endoplasmic reticulum (ER) and the Golgi apparatus. The vital biological functions served by protein glycosylation can be separated into two types. The first is the role of glycosylation in the extracellular environment, where a variety of sugar chains participate in protein secretion and stability, cell-cell adhesion and signaling, innate immunity, embryogenesis, and morphogenesis. Another role is in quality control of glycoproteins in the ER, a topic that has received recent attention. Quality control of glycoproteins is categorized into three kinds of reactions; the first is folding of newly synthesized glycoproteins, the second is ER-associated degradation of terminally misfolded or unassembled glycoproteins, and the last is sorting and transport of glycoproteins between organelles. In all three processes, N-glycans on the glycoproteins are used as tags to initiate the reactions. The process of glycosylation is conserved in yeast, plants, invertebrates and vertebrates, including mammals. Here, I focus on the intracellular lectins that participate in these processes and discuss the role of glycosylation based on the structural differences of N-glycans.

Design and Synthesis of Novel N-tert-butyl-N-substitutedbenzoyl-N- [dihydrobenzofuran(chroman)]carbohydrazide Derivatives as Potential Insect Growth Regulators

Six of new N-tert-butyl-N-substitutedbenzoyl-N-(2,4-dimethyl-2,3-dihydrobenzofuran)-7-carbohydrazide derivatives and five of new N-tert-butyl-N-substitutedbenzoyl-N-(5-methylchroman)-8-carbohydrazide derivatives were designed and synthesized from m-cresol. The synthesis highlighted that some kinds of reactions were ameliorated in methodology. An important feature is that 1-(3-allyl-2-hydroxy-4-methylphenyl)ethanone can easily be transformed into 1-(2,3-dihydro-2,4-dimethylbenzofuran-7-yl)ethanone just with concentrated sulfuric acid as catalyst. In addition, we found that 1-(5-methyl-2H-chromen-8-yl)ethanone could not be reduced to 1-(5-methylchroman-8-yl)ethanone directly by hydrogen with Pd/C as catalyst. It is an effective method for protecting 1-(5-methyl-2H-chromen-8-yl)ethanone with ethylene glycol to obtain 5-methyl-8-(2-methyl-1,3-dioxolan-2-yl)-2H-chromene and then reducing by hydrogen with Pd/C as catalyst to produce 1-(5-methylchroman-8-yl)ethanone in one step. Furthermore, SOCl2 can convert 2,3-dihydro-2,4- dimethylbenzofuran-7-carboxylic acid to 2,3-dihydro-2,4-dimethylbenzofuran-7-carbonyl chloride, but it is inefficient for transforming 5-methylchroman-8-carboxylic acid to the corresponding acyl chloride. Hence, different heterocycles on the benzene ring of benzoheterocyle moiety have influence on the reaction property of the corresponding acid.

ChemInform Abstract: A Gold(I)‐Catalyzed Intramolecular Reaction of Propargylic/Homopropargylic Alcohols with Oxirane.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hydrothermal vents and the origin of life

Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. There are striking parallels between the chemistry of the H(2)-CO(2) redox couple that is present in hydrothermal systems and the core energy metabolic reactions of some modern prokaryotic autotrophs. The biochemistry of these autotrophs might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of life. Hydrothermal vents thus unite microbiology and geology to breathe new life into research into one of biology's most important questions - what is the origin of life?

Sb–V–O-based catalysts for the ammoxidation of propane with a fluidized bed reactor

Propane ammoxidation is usually investigated with fixed-bed reactors at laboratory scale; however, this kind of reactions takes place over fluid-bed reactors in industry. The present paper investigates the catalytic ammoxidation of propane over supported Sb–V–O catalysts using a fluidized bed microreactor. The effect of support, Sb/V atomic ratio, Sb + V total coverage, synthesis procedures, as well as the effect of Nb as additive of the Sb–V–O system were evaluated. The activity results show that the selectivity trends are quite similar to those obtained with a fixed-bed reactor but a higher amount of active phase is necessary for the fluidized bed catalysts to obtain similar acrylonitrile yields.

ENZYME ISOFORMS MAY INCREASE PHENOTYPIC ROBUSTNESS

Enzyme isoforms are found in many cellular reactions, and can differ in the kind of reaction they catalyze, in their substrate affinity, or in their reaction rates. The evolutionary significance of enzyme isoforms is only partially understood. We used mathematical modeling to investigate the hypothesis that isoforms may be favored by selection because they can increase the phenotypic robustness of the system. We modify a model for circadian clock gene expression in Drosophila to incorporate the presence of isoforms in the phosphorylation pathway of the period gene. We consider the case in which different isoforms catalyze the same reaction but have different affinities for the substrate. Stability is increased if there is dynamic control of the expression of isoforms relative to each other. Thus, we show that controlling isoform proportion can be a powerful mechanism for reducing the effects of variations in the values of system parameters, increasing system robustness.

Theoretical Investigations of the Reactivities of Cationic Six-membered Carbene Analogues of Group 14 Elements

The potential energy surfaces for the chemical reactions of cationic six-membered group 14 heavy carbene species have been studied using density functional theory (B3LYP/LANL2DZ) and CCSD (CCSD/LANL2DZ//B3LYP/LANL2DZ) methods. Five six-membered group 14 cationic heavy carbene species, [HC(CMeNPh)2E:](+), where E = C, Si, Ge, Sn, and Pb, have been chosen as model reactants in this work. Also, four kinds of chemical reaction, C-H bond insertion, multiple bond cycloaddition, dimerization, and O-H bond insertion, have been used to study the chemical reactivities of these group 14 cationic carbene species. Basically, our present theoretical work predicts that the larger the angle NEN bond angle and the smaller the singlet-triplet splitting of the carbene, the lower its activation barriers will be and, in turn, the more rapid are its chemical reactions with other species. Moreover, the theoretical investigations suggest that the relative carbenic reactivity decreases in the order C > Si > Ge > Sn > Pb. That is, the heavier the group 14 atom (E), the more stable is its cationic carbene toward chemical reaction. As a result, we predict that the cationic six-membered group 14 carbene species (E = C, Si, Ge, Sn, and Pb) should be stable, readily synthesized, and isolated at room temperature. Our computational results are in good agreement with the available experimental observations. Furthermore, the singlet-triplet energy splitting of the carbene, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict its reactivities. The results obtained allow a number of predictions to be made.

Investigating The Management Strategies Of Misbehaviors Disrupting The Flow Of A Lesson

In a classroom, it is inevitable to experience misbehaved demeanors that disrupt the flow of a lesson and in turn, interrupt the teaching-learning process. These demeanors are labeled as undesirable or improper behaviors. Although exist many alternatives to manage these behaviors, there are two fundamental strategies in use: the first and preferred one is to prepare a teaching environment which does not allow emanation of such behaviors; if this option fails and these misbehaviors still appear in the classroom, then the second strategy is to intervene and stop them. In that context, several approaches, models and reaction methods have been developed to manage these undesired behaviors. Among the options, especially the ones that take up the least amount of learning time come to forefront when the reactions by the teachers to the misbehaved demeanors are concerned. Dealing with the aforementioned context, this study is carried out to contribute to the administration of a classroom in general and effective management of misbehaviors specifically. In the scope of this study, there are 21 elementary schools located in the city of Erzincan; teachers have been observed for a total of 737 lesson hours in terms of their reactions to misbehaviors that disrupt the flow of a les- son and their reactions have been recorded. According to the research results, teachers exhib- ited mostly calling the student with their names as a kind of reaction against the misbehaviors that disrupt the flow of a lesson, preferring a reaction of gazing at student from the reactions that take the least learning time

Neuronal Processes Involved in Subjective Feeling Emergence: Oscillatory Activity During an Emotional Monitoring Task

Subjective feeling, defined as the conscious experience of emotion and measured by self-report, is generally used as a manipulation check in studying emotional processes, rather than being the primary focus of research. In this paper, we report a first investigation into the processes involved in the emergence of a subjective feeling. We hypothesized that the oscillatory brain activity presumed to underlie the emergence of a subjective feeling can be measured by electroencephalographic (EEG) frequency band activity, similar to what has been shown in the literature for the conscious representation of objects. Emotional reactions were induced in participants using static visual stimuli. Episodes for which participants reported a subjective feeling were compared to those that did not lead to a conscious emotional experience, in order to identify potential differences between these two kinds of reactions at the oscillatory level. Discrete wavelet transforms of the EEG signal in gamma (31-63 Hz) and beta (15-31 Hz) bands showed significant differences between these two types of reactions. In addition, whereas beta band activities were widely distributed, differences in gamma band activity were predominantly observed in the frontal and prefrontal regions. The results are interpreted and discussed in terms of the complexity of the processes required to perform the affective monitoring task. It is suggested that future work on coherent mental representation of multimodal reaction patterns leading to the emergence of conscious emotional experience should include modifications in the time window examined and an extension of the frequency range to be considered.

Kinetics and mechanisms of iron redox reactions in silicate melts: The effects of temperature and alkali cations

The kinetics and the mechanisms of iron redox reactions in molten Fe-bearing pyroxene compositions have been investigated by Raman spectroscopy and X-ray absorption Near Edge Structure (XANES) experiments at the iron K-edge. The former experiments have been made only near the glass transition whereas the latter have also been performed from about 1300 to 2100 K. The same kinetics are observed with both techniques. They are described by characteristic times that depend primarily on temperature and not on the initial redox state. At high temperatures, where both kinds of reactions could be investigated, these times are similar for oxidation and reduction. From these characteristic times we have calculated as a function of temperature and composition a parameter termed effective redox diffusivity. For a given melt, the diffusivities follow two distinct Arrhenius laws, which indicate that the mechanisms of the redox reaction are not the same near the glass transition and at high temperatures. As is now well established, diffusion of divalent cations is the dominant mechanism at low temperatures but the enhanced kinetics observed for alkali-bearing melts indicate that Li + and Na + also participate in ionic transport. At superliquidus temperatures, in contrast, diffusion of oxygen represents the dominant mechanism.

Correlation of Crystal Structures, Electronic Structures, and Photocatalytic Properties in a Series of Ag-based Oxides: AgAlO2, AgCrO2, and Ag2CrO4

Three Ag-based oxides, AgAlO2, AgCrO2, and Ag2CrO4, were prepared by the cation exchange method. Powder X-ray diffraction analysis showed that AgAlO2 and Ag2CrO4 crystallized in orthorhombic structures and AgCrO2 crystallized in a hexagonal structure. The band gaps of AgAlO2, AgCrO2, and Ag2CrO4 were estimated to be 2.95, 1.68, and 1.75 eV, respectively. The photooxidation of Methyl Orange and gaseous benzene were performed to test the activities of the three materials. In the two kinds of reactions, the activity orders were both Ag2CrO4 > AgAlO2 > AgCrO2, and it was found that the novel photocatalyst, Ag2CrO4, showed activity in the visible region up to 570 nm. The correlation among crystal structures, electronic structures, and photocatalytic properties in the three Ag-based oxides is discussed in detail.

Granulation tissue in palpebral conjunctivae associated with acitretin therapy

To the Editor: We would like to report the development of excess granulation tissue during treatment with acitretin on palpebral conjunctivae. This is a unique complication because this kind of reaction normally appears on nail sulcus or on acne lesions.

空気圧入法適用性に関する評価スタディ

Recently, High Pressure Air Injection (HPAI) is considered to be an effective EOR method to light oil reservoirs. HPAI has some remarkable merits as follows. (1) Injection gas source is air, which can be supplied anywhere. (2) Initial and operation costs are inexpensive because the main facility required is only air compressor and air is free. (3) Air can be applied even in low permeable reservoirs where water cannot be injected. However, it is pointed out that the evaluation method for HPAI is difficult, because oxidation and combustion reactions are complicated. A Japanese domestic oil field has been investigated to apply HPAI since 1999.A series of experiments is essential in HPAI study. Accelerating Rate Calorimeter (ARC) test and Combustion Tube (CT) test are generally conducted to evaluate a potential of air injection in fields. ARC test is used to determine the extent and continuity of reactions in the low and high temperature range. The purposes of the CT test are (1) to assess the overall burning characteristics of oil, (2) to measure incremental oil production, air and fuel requirements and other parameters and (3) to measure produced gas compositions and oil and water production to provide benchmarks for monitoring future field operations.The results of ARC tests suggest that the ignition temperature of the oil may be higher than the reservoir temperature. It means an artificial ignition method should be conducted for HPAI in the field. Additional ARC tests were carried out to assess the influence of oxygen slug, NO2 addition and linseed oil on ignition temperature as the ignition method. The experimental results suggest that the linseed oil method is the most promising, because the ignition temperature with high concentration of linseed oil is below the reservoir temperature. Two CT tests were also conducted, in low water saturation case and high water saturation case after waterflooding, to estimate applicability of HPAI including on tertiary mode. Both tests show stable combustion performance in terms of temperature, pressure response, produced gas compositions and incremental oil production.On the other hand, numerical simulation is important to predict field production performance. The appropriate reaction kinetics on the combustion has to be used in the numerical simulation. History matching with CT tests was conducted to obtain the kinetics. Two kinds of reactions, “oxidation reaction” and “combustion reaction” were used in the study. In the former reaction, oxygen is consumed by the oil to form oxidation compounds. In the latter one, oxygen reacts with the compounds to form carbon dioxide and water. Reaction parameters were used as matching parameters. Good results of history matching with both CT tests using same reaction kinetics were obtained.