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Sample records for alkali-silica reaction observed

  1. In situ alkali-silica reaction observed by x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kurtis, K.E.; Monteiro, P.J.M. [Univ. of California, Berkeley, CA (United States); Brown, J.T.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction.

  2. Effect of Mineral Admixtures on Alkali-Silica Reaction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chengzhi; WANG Aiqin

    2008-01-01

    The influence of silica fume,slag and fly ash on alkali-silica reaction under the condition of 70℃ is studied.The results show that silica,slag and fly ash may inhibit alkali-silica reaction only under suitable content.When the content is less than 10%,silica fume does not markedly influence the expansion of alkali-silica reaction.When the content is 15%-20%,silica fume only may delay the expansion of alkali-silica reaction.When the content is 30%-70%,slag may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is 10%,fly ash does not markedly influence the expansion of alkali-silica reaction.When the content is 20%-30%,fly ash may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is over 50%,it is possible that fly ash can inhibit effectively alkali-silica reaction.

  3. Effect of Pozzolanic Reaction Products on Alkali-silica Reaction

    Institute of Scientific and Technical Information of China (English)

    WEI Fengyan; LAN Xianghui; LV Yinong; XU Zhongzi

    2006-01-01

    The effect of fly ash on controlling alkali-silica reaction (ASR) in simulated alkali solution was studied. The expansion of mortar bars and the content of Ca(OH)2 in cement paste cured at 80 ℃ for 91 d were measured. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were employed to study the microstructure of C-S-H. TEM/energy dispersive spectroscopy (EDS) was then used to determine the composition of C-S-H. The pore structure of the paste was analyzed by mercury intrusion porosimetry (MIP). The results show that the contents of fly ash of 30% and 45% can well inhibit ASR. And the content of Ca(OH)2 decreases with the increase of fly ash. That fly ash reacted with Ca(OH)2 to produce C-S-H with a low Ca/Si molar ratio could bind more Na+ and K+ ions, and produce a reduction in the amount of soluble alkali available for ASR. At the same time, the C-S-H produced by pozzolanic reaction converted large pores to smaller ones (gel pores smaller than 10 nm) to densify the pore structure. Perhaps that could inhibit alkali transport to aggregate for ASR.

  4. Influence of alkalis from different sources than cement in the evolution of alkali-silica reaction

    OpenAIRE

    Olague, C.; Wenglas, G.; Castro, P

    2003-01-01

    A bibliographical revision of the existent literature allows showing symptoms of alkali-silica reaction (ASR) in highways, and the practical and economic method uranyl acetate to confirm the presence of ASR. The existence of reaction in concrete pavements of Chihuahua City was verified by a visual observation of patterns cracks, examination of gel deposits and the presence of reactive materials. Considering that the cement used to construct this pavements with problems of ASR, was low alkalis...

  5. Effect of Anti-freezing Admixtures on Alkali-silica Reaction in Mortars

    Institute of Scientific and Technical Information of China (English)

    LIU Junzhe; LI Yushun; LV Lihua

    2005-01-01

    The influence of anti-freezing admixture on the alkali aggregate reaction in mortar was analyzed with accelerated methods. It is confirmed that the addition of sodium salt ingredients of anti-freezing admixture accelerates the alkali silica reaction to some extent, whereas calcium salt ingredient of anti-freezing admixture reduces the expansion of alkali silica reaction caused by high alkali cement. It is found that the addition of the fly ash considerably suppresses the expansion of alkali silica reaction induced by the anti-freezing admixtures.

  6. Concrete alkali-silica reaction and nuclear radiation damage

    International Nuclear Information System (INIS)

    The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 108 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

  7. Assessment of concrete bridge decks with alkali silica reactions

    DEFF Research Database (Denmark)

    Eriksen, Kirsten; Jansson, Jacob; Geiker, Mette Rica

    2008-01-01

    Based on investigations of concrete from an approximately 40 years old bridge a procedure to support the management of maintenance and repair of alkali silica damaged bridges is proposed. Combined petrography and accelerated expansion testing were undertaken on cores from the Bridge at Skovdiget......, Bagsværd, Denmark to provide information on the damage condition as well as the residual reactivity of the concrete. The Danish Road Directory’s guidelines for inspection and assessment of alkali silica damaged bridges will be briefly presented, and proposed modifications will be describe...

  8. Alkali-silica reaction resistant concrete using pumice blended cement

    Science.gov (United States)

    Ramasamy, Uma

    Durability of structures is a major challenge for the building industry. One of the many types of concrete deterioration that can affect durability is alkali-silica reaction (ASR). ASR has been found in most types of concrete structures, including dams, bridges, pavements, and other structures that are 20 to 50 years old. The degradation mechanism of ASR produces a gel that significantly expands in the presence of water as supplied from the surrounding environment. This expansion gel product can create high stresses and cracking of the concrete, which can lead to other forms of degradation and expensive structural replacement costs. The four essential factors that produce an expansive ASR gel in concrete are the presence of alkalis, siliceous aggregate, moisture, and free calcium hydroxide (CH). If concrete is starved of any one of these essential components, the expansion can be prevented. Reducing CH through the use of a supplementary cementitious material (SCM) such as natural pozzolan pumice is the focus of this research. By using a pozzolan, the amount of CH is reduced with time based on the effectiveness of the pozzolan. Many pozzolans exist, but one such naturally occurring pozzolanic material is pumice. This research focuses on determining the effect of a finely ground pumice as a SCM in terms of its resistance to ASR expansion, as well as improving resistance to other potential concrete durability mechanisms. In spite of having high alkali contents in the pumice, mixtures containing the SCM pumice more effectively mitigated the ASR expansion reaction than other degradation mechanisms. Depending on the reactivity of the aggregates and fineness of the pumice, 10-15% replacement of cement with the pumice was found to reduce the ASR expansion to the acceptable limits. The amount of CH remaining in the concrete was compared to the ASR expansion in order to improve understanding of the role of CH in the ASR reaction. Thermo-gravimetric analysis (TGA) and X

  9. Alkali-Silica Reaction Inhibited by LiOH and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A high alkali reactive aggregate-zeolitization perlite was used to test the long-term effectiveness of LiOH in inhibiting alkali-silica reaction.In this paper,the rigorous conditions were designed that the mortar bars had been cured at 80℃ for 3 years after autoclaved 24 hours at 150℃.Under this condition,LiOH was able to inhibit the alkali-silica reaction long-term effectiveness.Not only the relationship between the molar ratio of n(Li)/(Na) and the alkali contents in systems was established, but also the governing mechanism of such effects was also studied by SEM.

  10. The alkali-silica reaction: mineralogical and geochemical aspects of some Dutch concretes and Norwegian mylonites

    NARCIS (Netherlands)

    Broekmans, M.A.T.M.

    2002-01-01

    Maarten Broekmans has studied the alkali-silica reaction in two Dutch concretes by means of optical microscopy, geochemical analyses on bulk material and after selective digestion in acid, and with element mapping in polished thin sections. He furthermore characterized the nature of the silica/quart

  11. Effect of the Composite of Natural Zeolite and Fly Ash on Alkali-Silica Reaction

    Institute of Scientific and Technical Information of China (English)

    FENG Xiao-xin; FENG Nai-qian; HAN Dong

    2003-01-01

    The effect of the composite of natural zeolite and fly ash on alkali-silica reaction ( ASR ) was studied with natural alkali-reactive aggregate and quartz glass aggregate respecthvely. The expansive experiment of mortar bar and concrete prism was completed. The results show that ASR can be suppressed effectively by the composite of natural zeolite and fly ash.

  12. Influence of Water on Alkali-Silica Reaction: Experimental Study and Numerical Simulations

    OpenAIRE

    POYET, Stéphane; Sellier, Alain; Capra, Bruno; Thèvenin-Foray, Geneviève; Torrenti, Jean-Michel; Tournier-Cognon, Hélène; Bourdarot, Eric

    2006-01-01

    International audience; Alkali-Silica Reaction (ASR) is a concrete pathology due to chemical reactions involving reactive silica from reactive aggregates and the inner solution of concrete. Main effects are swelling, cracking and the reduction in the mechanical properties of affected concretes. Water is very important for ASR, the more available water the more expansion and degradation. This article presents new laws for the modelling of the influence of water upon ASR. They are based on expe...

  13. Detection of alkali-silica reaction swelling in concrete by staining

    Science.gov (United States)

    Guthrie, Jr., George D.; Carey, J. William

    1998-01-01

    A method using concentrated aqueous solutions of sodium cobaltinitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.

  14. Influence of alkalis from different sources than cement in the evolution of alkali-silica reaction

    Directory of Open Access Journals (Sweden)

    Olague, C.

    2003-12-01

    Full Text Available A bibliographical revision of the existent literature allows showing symptoms of alkali-silica reaction (ASR in highways, and the practical and economic method uranyl acetate to confirm the presence of ASR. The existence of reaction in concrete pavements of Chihuahua City was verified by a visual observation of patterns cracks, examination of gel deposits and the presence of reactive materials. Considering that the cement used to construct this pavements with problems of ASR, was low alkalis cement, the research was devoted to study the influence of alkalis coming from different sources than cement in the evolution of reaction such as: a aggregates: gravel and sand, b mix water, c additives and d minerals additions The initial classification of cements like high and low alkalis concerned to ASR must be revised for accept the fact that there is not a unique maximum limit alkalis of cement under which the expansible reactivity cannot occur.

    Una revisión bibliográfica de la literatura existente permite mostrar las manifestaciones de reacción álcali-sílice (RAS en estructuras de carreteras y el método práctico y económico de acetato de uranilo para confirmar la presencia de RAS. La existencia de la reacción en pavimentos de hormigón de la ciudad de Chihuahua se pudo confirmar tras la observación visual de modelos de grietas, estudios de depósitos de gel y existencia de fuentes de materiales reactivos. Considerando que el cemento utilizado para construir los tramos de pavimento con problemas de RAS, era un cemento bajo en álcalis, se enfocó la investigación al estudio de la influencia de los álcalis provenientes de fuentes distintas al cemento en la evolución de la reacción tales como: a áridos gruesos y finos, b agua de mezclado, c aditivos y d adiciones minerales El concepto inicial de clasificación de cementos altos y bajos en álcalis con respecto a la RAS debe ser revisado para aceptar el hecho de que no hay un solo

  15. Insights into alkali-silica reaction damage in mortar through acoustic nonlinearity

    Science.gov (United States)

    Rashidi, M.; Kim, J.-Y.; Jacobs, L. J.; Kurtis, K. E.

    2016-02-01

    The progression of damage as a result of alkali-silica reaction in mortar samples is monitored by using the Nonlinear Impact Resonance Acoustic Spectroscopy (NIRAS) method and expansion measurements, which were performed daily. Results of this study show a strong correlation between the cumulative average nonlinearity parameter and expansion for each sample type, and a strong linear relationship between fourteen-day expansion and the cumulative average nonlinearity of among sample types. In addition to the cumulative average nonlinearity parameter, the standard deviation of average nonlinearity parameter shows strong correlation with the fourteen-day expansion of sample types. Results provide insights to the relationship with the acoustic nonlinearity and damage caused by the ASR.

  16. Microstructural Changes Due to Alkali-Silica Reaction during Standard Mortar Test

    Directory of Open Access Journals (Sweden)

    Jun-Ho Shin

    2015-12-01

    Full Text Available The microstructural development of mortar bars with silica glass aggregate undergoing alkali-silica reaction (ASR under the conditions of American Society for Testing and Materials (ASTM Standard Test C1260 was analyzed using scanning electron microscopy and qualitative X-ray microanalysis. Cracking in the aggregate, the hydrated paste, and the paste-aggregate interface was important in the development of the microstructure. Cracks were characterized according to their location, their relationship to other cracks, and whether they are filled with ASR gel. Expansion of the bars was approximately 1% at 12 days and 2% at 53 days. They fell apart by 63 days. The bars contained two zones, an inner region that was undergoing ASR and an outer and much more highly damaged zone that extended further inward over time. Evidence of ASR was present even during the period when specimens were immersed in water, prior to immersion in NaOH solution.

  17. Modeling of alkali-silica reaction in concrete:a review

    Institute of Scientific and Technical Information of China (English)

    D.R.J.OWEN

    2012-01-01

    This paper presents a comprehensive review of modeling of alkali-silica reaction (ASR) in concrete.Such modeling is essential for investigating the chemical expansion mechanism and the subsequent influence on the mechanical aspects of the material.The concept of ASR and the mechanism of expansion are first outlined,and the stateof-the-art of modeling for ASR,the focus of the paper,is then presented in detail.The modeling includes theoretical approaches,meso-and macroscopic models for ASR analysis.The theoretical approaches dealt with the chemical reaction mechanism and were used for predicting pessimum size of aggregate.Mesoscopic models have attempted to explain the mechanism of mechanical deterioration of ASR-affected concrete at material scale.The macroscopic models,chemomechanical coupling models,have been generally developed by combining the chemical reaction kinetics with linear or nonlinear mechanical constitutive,and were applied to reproduce and predict the long-term behavior of structures suffering from ASR.Finally,a conclusion and discussion of the modeling are given.

  18. Monitoring, Modeling, and Diagnosis of Alkali-Silica Reaction in Small Concrete Samples

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gribok, Andrei V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. This report describes alkali-silica reaction (ASR) degradation mechanisms and factors influencing the ASR. A fully coupled thermo-hydro-mechanical-chemical model developed by Saouma and Perotti by taking into consideration the effects of stress on the reaction kinetics and anisotropic volumetric expansion is presented in this report. This model is implemented in the GRIZZLY code based on the Multiphysics Object Oriented Simulation Environment. The implemented model in the GRIZZLY code is randomly used to initiate ASR in a 2D and 3D lattice to study the percolation aspects of concrete. The percolation aspects help determine the transport properties of the material and therefore the durability and service life of concrete. This report summarizes the effort to develop small-size concrete samples with embedded glass to mimic ASR. The concrete samples were treated in water and sodium hydroxide solution at elevated temperature to study how ingress of sodium ions and hydroxide ions at elevated temperature impacts concrete samples embedded with glass. Thermal camera was used to monitor the changes in the concrete sample and results are summarized.

  19. A computational linear elastic fracture mechanics-based model for alkali-silica reaction

    International Nuclear Information System (INIS)

    This article presents a fracture mechanics model for Alkali-Silica Reaction (ASR). The model deals with the case of a concrete made up of dense aggregates submitted to chemical attack. The chemistry and diffusion (of ions and gel) are not modelled. The focus is put on the mechanical consequences of the progressive replacement of the outer layer of the aggregate by a less dense gel. A schematic cracking pattern is assumed: a ring-shaped crack appears in the cement paste surrounding the spherical aggregate depending on the pressure build-up. The onset of cracking is determined using an incremental energy criterion. The stored elastic energy and deformation of a given configuration are determined assuming that each aggregate behaves as if it was embedded in an infinite cement paste matrix. The calculations are performed by Finite Element Analysis. We note a very different behaviour of aggregates of different sizes. Adding the contributions of different aggregate sizes leads to an estimation of the global free expansion of a concrete of given aggregate size distribution. A rate of attack is identified that leads to recover the usual sigmoid ASR expansion curve. (authors)

  20. Classification of alkali-silica reaction and corrosion distress using acoustic emission

    Science.gov (United States)

    Abdelrahman, Marwa; ElBatanouny, Mohamed; Serrato, Michael; Dixon, Kenneth; Larosche, Carl; Ziehl, Paul

    2016-02-01

    The Nuclear Regulatory Commission regulates approximately 100 commercial nuclear power reactor facilities that contribute about 20% of the total electric energy produced in the United States. Half of these reactor facilities are over 30 years old and are approaching their original design service life. Due to economic and durability considerations, significant portions of many of the facilities were constructed with reinforced concrete, including the containment facilities, cooling towers, and foundations. While most of these concrete facilities have performed exceptionally well throughout their initial expected service life, some are beginning to exhibit different forms of concrete deterioration. In this study, acoustic emission (AE) is used to monitor two main concrete deterioration mechanisms; alkali-silica reaction (ASR) distress and corrosion of reinforcing steel. An accelerated ASR test was conducted where specimens were continuously monitored with AE. The results show that AE can detect and classify damage due to ASR distress in the specimens. AE was also used to remotely monitor active corrosion regions in a reactor facility. AE monitoring of accelerated corrosion testing was also conducted on a concrete block specimen cut from a similar reactor building. Electrochemical measurements were conducted to correlate AE activity to quantifiable corrosion measurements and to enhance capabilities for service life prediction.

  1. Microwave material characterization of alkali-silica reaction (ASR) gel in cementitious materials

    Science.gov (United States)

    Hashemi, Ashkan

    Since alkali-silica reaction (ASR) was recognized as a durability challenge in cement-based materials over 70 years ago, numerous methods have been utilized to prevent, detect, and mitigate this issue. However, quantifying the amount of produced ASR byproducts (i.e., ASR gel) in-service is still of great interest in the infrastructure industry. The overarching objective of this dissertation is to bring a new understanding to the fundamentals of ASR formation from a microwave dielectric property characterization point-of-view, and more importantly, to investigate the potential for devising a microwave nondestructive testing approach for ASR gel detection and evaluation. To this end, a comprehensive dielectric mixing model was developed with the potential for predicting the effective dielectric constant of mortar samples with and without the presence of ASR gel. To provide pertinent inputs to the model, critical factors on the influence of ASR gel formation on dielectric and reflection properties of several mortar samples were investigated at R, S, and X-band. Effects of humidity, alkali content, and long-term curing conditions on ASR-prone mortars were also investigated. Additionally, dielectric properties of chemically different synthetic ASR gel were also determined. All of these, collectively, served as critical inputs to the mixing model. The resulting developed dielectric mixing model has the potential to be further utilized to quantify the amount of produced ASR gel in cement-based materials. This methodology, once becomes more mature, will bring new insight to the ASR reaction, allowing for advancements in design, detection and mitigation of ASR, and eventually has the potential to become a method-of-choice for in-situ infrastructure health-monitoring of existing structures.

  2. The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust On the Alkali-Silica Reaction in Concrete

    OpenAIRE

    James Sarfo-Ansah; Eugene Atiemo

    2015-01-01

    The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR). Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar...

  3. Alkali-silica reaction of aggregates for concrete pavements in Chihuahua’s State, Mexico

    Directory of Open Access Journals (Sweden)

    Olague, C.

    2002-12-01

    Full Text Available The concrete of pavements must resist the climatic conditions, heavy traffic, chemical agents or any other type of aggressive agent. A methodology for characterizing materials that would influence concrete durability was developed considering chemical and physical factors. This methodology allows the consideration of several factors like physiography, geology, and climate, among others that would be of great importance to prevent future durability problems of pavements. This methodology takes into account several tests and this paper presents the results of potential reactivity aggregates of the State of Chihuahua. The tests for evaluating the reactive siliceous aggregate and the potential alkali-silica reactivity were performed according to the: petrographic examination (ASTM C 295 and standard quick chemical test (ASTM C 289. 38% of the tested sites resulted innocuous, 48% potentially reactive and 13% reactive. It is discussed the benefit of applying a conscious methodology in order to obtain the best results with a representative quantity of tests.

    El hormigón de los pavimentos debe ser resistente a las condiciones climáticas, tránsito pesado, agentes químicos o cualquier otro tipo de agente agresivo. Se desarrolló una metodología para caracterización de materiales considerando factores físicos y químicos que influyen en la durabilidad del hormigón. Esta metodología se basa en la consideración de varios factores como: fisiografía, geología y clima, entre otros, que podrían ser de gran importancia para prevenir futuros problemas de durabilidad en pavimentos de hormigón. La metodología en cuestión considera varias pruebas, en este artículo se presentan los resultados de la reactividad potencial de los áridos del Estado de Chihuahua. Las pruebas para evaluar la reactividad de áridos silíceos y la reactividad potencial álcali-sílice fueron ejecutadas de acuerdo a: examen petrográfico (ASTM C 295 y la prueba qu

  4. Alkali-silica reactions of mortars produced by using waste glass as fine aggregate and admixtures such as fly ash and Li2CO3.

    Science.gov (United States)

    Topçu, Ilker Bekir; Boğa, Ahmet Raif; Bilir, Turhan

    2008-01-01

    Use of waste glass or glass cullet (GC) as concrete aggregate is becoming more widespread each day because of the increase in resource efficiency. Recycling of wastes is very important for sustainable development. When glass is used as aggregate in concrete or mortar, expansions and internal stresses occur due to an alkali-silica reaction (ASR). Furthermore, rapid loss in durability is generally observed due to extreme crack formation and an increase in permeability. It is necessary to use some kind of chemical or mineral admixture to reduce crack formation. In this study, mortar bars are produced by using three different colors of glass in four different quantities as fine aggregate by weight, and the effects of these glass aggregates on ASR are investigated, corresponding to ASTM C 1260. Additionally, in order to reduce the expansions of mortars, 10% and 20% fly ash (FA) as mineral admixture and 1% and 2% Li(2)CO(3) as chemical admixture are incorporated by weight in the cement and their effects on expansion are examined. It is observed that among white (WG), green (GG) and brown glass (BG) aggregates, WG aggregate causes the greatest expansion. In addition, expansion increases with an increase in amount of glass. According to the test results, it is seen that over 20% FA and 2% Li(2)CO(3) replacements are required to produce mortars which have expansion values below the 0.2% critical value when exposed to ASR. However, usages of these admixtures reduce expansions occurring because of ASR.

  5. Effect of Grain Size and Reaction Time in Characterisation of Aggregates for Alkali Silica Reaction Using Chemical Method

    Directory of Open Access Journals (Sweden)

    R.P. Pathak

    2016-04-01

    Full Text Available Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates. Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure completion of reaction as the observations are limited to 24hour only and also does not assess the effect of varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide solution after the reaction seems to be much more meaningful in justifying the silica release.

  6. The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust On the Alkali-Silica Reaction in Concrete

    Directory of Open Access Journals (Sweden)

    James Sarfo-Ansah

    2015-08-01

    Full Text Available The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR. Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar bar samples confirmed the formation of an expansive sodium silica gel in the reference Portland cement mortar bar as the agent responsible for ASR. Stable calcium silicates were formed in the mortar bars containing calcined clay in increasing quantities whilst the presence of the sodium silicate gel decreased.The occurrence of these stable silicates in hydrated samples containing steel slag and granite dust was however minimal, compared to calcined clay cement mortars. The highest expansion was recorded for granite dust mortar bars, reaching a maximum of 25.98% at 35 days. Mortar-bar expansion decreased as calcined clay content in the cement increased;mortar bars with 25% calcined clay were the least expansive recording expansion less than 0.1% at all test ages. Whilst the expansion was reduced by between 42.5% and 107.8% at 14 days with increasing calcined clay content, expansion rather increased between 36.8% and 169.5% at 14 days with increasing granite dust content.Steel slag mortar bars experienced reduction in 14 days expansion between 14.3% - 46.2%.The study confirms that steel slag and calcined clay pozzolan have greater influence on ASR in mortar bars than granite dust and shows that calcined clay and low CaO steel slag could be considered as remedial admixtures for ASR at replacement levels of 25% and 15% respectively.

  7. GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

    International Nuclear Information System (INIS)

    Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document the progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we've implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture

  8. GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Vanderbilt Univ., Nashville, TN (United States)

    2015-09-01

    Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document the progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we’ve implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture

  9. Durability of Concrete Subjected to the Combined Action of Alkali-silica Reaction and Sulfate Attack%碱-硅酸反应和硫酸盐侵蚀复合作用下的混凝土耐久性

    Institute of Scientific and Technical Information of China (English)

    沈佳燕; 施韬; 杨杨

    2012-01-01

    碱-硅酸反应(ASR)和硫酸盐侵蚀是影响混凝土耐久性的两个重要因素.目前,对于单一因素作用下混凝土劣化过程的研究已有诸多报道,但关于混凝土在碱-硅酸反应和硫酸盐侵蚀复合作用下的损伤失效过程及机理研究却很少.本文介绍了近年来国内外在碱-硅酸反应和硫酸盐侵蚀方面的研究现状,主要阐述了它们各自的膨胀机理和抑制措施.在对Grattan等人试验中得到的膨胀数据、X射线衍射图和扫描电子显微镜图进行分析的基础上,讨论了混凝土在这两种因素复合作用下可能出现的膨胀值变化和强度变化,并提出有效的抑制措施.%Alkali-silica reaction (ASR) and sulfate attack are two of the most important problems on concrete durability. The deterioration of concrete under single destructive action have been broadly investigated, but the damage process and the corresponding mechanisms subjected to combined action of ASR and sulfate attack have rarely studied yet. This paper introduces the recent research progress in alkali-silica reaction and sulfate attack achieved home and abroad,and mainly describes the expanding mechanisms and inhibitive measures of each reaction. The probable changes of expansion and strength of concrete subjected to combined action of ASR and sulfate attack are discussed on the base of analyzing experimental results of expansion, X-Ray diffractogram and SEM micrograph by Grattan el al, and the effective inhibitive measures are also been proposed.

  10. Structural evaluation of a prestressed concrete bridge under an alkali-silica reaction; Evaluacion estructural de un puente de hormigon pretensado afectado por una reaccion alcali-silice

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero Garcia, I.; Bermudez Adriozola, B.

    2010-07-01

    The Central Laboratory of Structures and Materials (CEDEX) was commissioned by the National Department of Highways to evaluate the safety conditions of one bridge built on 1997, which is part of the net of the Spanish National Highways. Even at the first inspection many cracks were detected in the concrete deck, associated with expansion concrete processes. This examination revealed that concrete deterioration was not associated with any reinforcement corrosion process; in fact, there were no symptoms of this pathology all along the bridge. for that reason the internal chemical reactions were considered as the most probable cause for the expansion of concrete, as no symptoms of deterioration due to external attack were found. In order to check the origin of concrete expansion, some tests were carried out on concrete samples drilled on the decks. Results of these tests show that there had been internal reactions in concrete mass which explains its expansion and the appearance of those cracks observed. Further more, some other activities were also carried out on site to estimate the importance of the structural damages, as topographic levelling and dynamic testing of the decks. Also the mechanical properties of concrete probes were tested at laboratory. This article shows the main results obtained on the study carried on to determine the cause and significance of the structural damages of the bridge. (Author) 3 refs.

  11. Estudo das reações alcalis-sílica associadas ao uso da lama vermelha em argamassas colantes e de revestimento Study of alkali-silica reactions associated with the use of red mud in plastering mortars

    Directory of Open Access Journals (Sweden)

    D. V. Ribeiro

    2012-03-01

    Full Text Available A incorporação de resíduos industriais em matrizes cimentícias, com o objetivo de inertização, é uma alternativa de reutilização que tem sido bastante estudada nos últimos anos. No presente trabalho, estudou-se a lama vermelha, resíduo sólido gerado no processo de beneficiamento da bauxita e que, devido a seu elevado pH, é considerado "perigoso". Apesar do uso deste resíduo ter sido reportada em trabalhos anteriores, algumas patologias podem estar associadas à sua utilização, devido à elevada concentração de íons alcalinos (principalmente o sódio, favorecendo as reações álcalis-sílica (RAS e às dificuldades de moldagem (reologia devido à elevada finura deste resíduo. Apesar destes prováveis problemas provenientes do uso indiscriminado da lama vermelha como adição às argamassas e concretos, ainda são poucas as pesquisas que os contemplam, sendo este o foco do presente trabalho. Foram verificadas as propriedades reológicas das argamassas, utilizando um reômetro e a avaliação da RAS, de acordo com as normas ASTM C 1260-07 e NBR 11582. Os resultados obtidos foram bastante satisfatórios quanto ao comportamento das argamassas frente à RAS, apesar da elevada concentração de álcalis na lama vermelha, com grande influência reológica.The incorporation of industrial wastes in cementitious matrices, with the goal of inertization, is an alternative of reuse that has been extensively studied in recent years. In this paper, the red mud, the main waste generated in aluminum and alumina production by the Bayer process from bauxite ore and considered "hazardous" due to the high pH, was studied. Despite the use of this waste have been reported in previous studies, some pathologies may be associated with its use, due to high concentration of alkali ions (mainly sodium, favoring the alkali-silica reactions (ASR and the difficulties of molding (rheology because of high fineness of this waste. Despite these potential

  12. 碱硅酸反应对水泥基材料力学性能的影响%Influence of Alkali-Silica Reaction on Mechanical Properties of Cementitious Materials

    Institute of Scientific and Technical Information of China (English)

    陈达; 杨一琛; 冯兴国; 欧阳峰

    2014-01-01

    通过对比活性不同的两种砂制备的砂浆试样在碱硅酸反应中的膨胀率,结合三轴抗压测试研究了碱硅酸反应前后水泥基材料的力学性能变化,分析了碱硅酸反应后材料微观结构演变与力学性能间的关系。结果表明碱惰性砂制备的砂浆试样中骨料周围局部区域形成少量针状凝胶相,由于碱硅酸反应速率较慢且凝胶相较少,因而其膨胀率较小且对水泥基材料力学性能的影响较小。碱活性砂制备的砂浆试样中,骨料周围易生成大量针状凝胶层,且随着碱硅酸反应的进行凝胶相膨胀加剧,促进水泥基材料中骨料周围的水泥浆体中形成大量裂纹,进而明显影响水泥基材料的力学性能。研究表明,三轴抗压测试中,除膨胀率外,极限抗压强度和应变量也可以作为评价水泥基材料碱硅酸反应水平的参量。%The expansion rate of mortars ,prepared with active sand and non-active sand ,under alkali-silica reaction (ASR) was recorded .The effects of ASR on mechanical properties of cementitious materials were studied by triaxial compression test .The relation between the microstructure of cementitious materials and the mechanical properties was investigated as well .The results showed that there was a little blade crystals gel formed in a local region near the aggregate in materials prepared with non-active sand .For the quantity of formed gel is small ,the expansion effects of ASR are limited .Whereas ,thick blade crystals gel layers formed near the aggregate when the active sand prepared materials subjected to ASR .Moreover ,the reactive products would lead to cracks and then significantly affects the mechanical properties of mortars . Additionally ,the results showed that besides the expansion rate ,the ultimate compressive strength and the strain are also effective indexes to estimate the influence of ASR .

  13. The role of residual cracks on alkali silica reactivity of recycled glass aggregates

    DEFF Research Database (Denmark)

    Maraghechi, Hamed; Shafaatian, Seyed-Mohammad-Hadi; Fischer, Gregor;

    2012-01-01

    Despite its environmental and economical advantages, crushed recycled glass has limited application as concrete aggregates due to its deleterious alkali-silica reaction. To offer feasible mitigation strategies, the mechanism of ASR should be well understood. Recent research showed that unlike some...... natural aggregates, soda-lime glass undergoes ASR within cracks in the interior of glass particles and not at glass–paste interface. These cracks originate during bottle crushing and propagate further by ASR. This paper examines whether glass aggregates could become innocuous if these cracks are healed...... percentages of reactive microcracks which may explain why ASR expansions are lowered by reducing the size of glass aggregates....

  14. Alkali-silica reactivity of expanded glass granules in structure of lightweight concrete

    Science.gov (United States)

    Bumanis, G.; Bajare, D.; Locs, J.; Korjakins, A.

    2013-12-01

    Main component in the lightweight concrete, which provides its properties, is aggregate. A lot of investigations on alkali silica reaction (ASR) between cement and lightweight aggregates have been done with their results published in the academic literature. Whereas expanded glass granules, which is relatively new product in the market of building materials, has not been a frequent research object. Therefore lightweight granules made from waste glass and eight types of cement with different chemical and mineralogical composition were examined in this research. Expanded glass granules used in this research is commercially available material produced by Penostek. Lightweight concrete mixtures were prepared by using commercial chemical additives to improve workability of concrete. The aim of the study is to identify effect of cement composition to the ASR reaction which occurs between expanded glass granules and binder. Expanded glass granules mechanical and physical properties were determined. In addition, properties of fresh and hardened concrete were determined. The ASR test was processed according to RILEM AAR-2 testing recommendation. Tests with scanning electron microscope and microstructural investigations were performed for expanded glass granules and hardened concrete specimens before and after exposing them in alkali solution.

  15. Nouvelle approche pour le suivi de la réactivité de phases SiO2 soumises à la Réaction Alcali Silice (RAS New approach for monitoring the reactivity of SiO2 phases subject to Alkali Silica Reaction (SAR

    Directory of Open Access Journals (Sweden)

    Harfouche M.

    2012-09-01

    Full Text Available Nous avons suivi- au moyen de la microscopie électronique à balayage environnementale (MEBE la diffraction X et la spectroscopie d’absorption des rayons X sous rayonnement synchrotron (XANES- la réactivité de certaines phases SiO2 lors du processus de la Réaction Alcali Silice (RAS. Cette réactivité est étroitement liée à la structure locale autour des atomes de silicium ainsi qu’à la présence d’impuretés comme le fer. Dans le cas du silex brut, la raie blanche du seuil K du fer ressemble davantage à celle de Fe3O4 ce qui permet de déduire la présence d’un mélange de Fe2+/Fe3+ dans le silex de départ. Après réaction, l’allure du spectre d’absorption des rayons X au seuil K du fer du silex est conservée avec un léger déplacement de la raie blanche vers les hautes énergies. Cette augmentation montre une prédominance de la valence Fe3+ au détriment de la valence Fe2+. Les résultats montrent que le fer participe à la stabilisation de la structure des phases formées. Cette étude peut être étendue à d’autres éléments traces présents dans la structure du silex de départ. In this study the reactivity of some SiO2 phases under Alkali Silica Reaction (RAS process is followed, using the environmental scanning electron microscopy (ESEM X-ray diffraction and absorption spectroscopy X-ray synchrotron radiation (XANES. This reactivity is closely related to the local structure around the silicon atoms and the presence of impurities such as iron. In the case of flint raw skate white iron K line is more like that of Fe3O4 which allows to deduce the presence of a mixture of Fe2+ / Fe3+ in the flint to start. After reaction, the shape of the spectrum of X-ray absorption K edge of iron in the flint is retained with a slight displacement of the white stripe to high energies. This increase shows a predominance of the valence Fe3+ at the expense of Fe2+ valence. The results show that iron is involved in stabilizing the

  16. The Mechanism of the Eeffect of Mineral Admixtures on the Expansion of Aalkali-silica Reaction

    Institute of Scientific and Technical Information of China (English)

    WANG Aiqin; Niu Jishou; ZHANG Chengzhi

    2008-01-01

    On the base of the influence rule of silica fume, slag and fly ash on alkali-silica reaction under the condition of 70℃, the mechanism of the effect of mineral admixtures on alkali-silica reaction is studied further in the paper. The results show that the effects of mineral admixtures on alkali-silica reaction are mainly chemistry effect and surface physichemistry effect. Under suitable condition, the chemistry effect may make alkali-silica reaction to be inhibited effectively, but the physichemistry effect only make alkali-silica reaction to be delayed. The chemistry effect and the physichemistry effect of minerals admixture are relative to the content of Ca(OH)2 in system. Under the condition that there is a large quantity of Ca(OH)2, mineral admixture cannot inhibit alkali-silica reaction effectively. Only when Ca(OH)2 in the system is very less, it is possible that mineral admixture inhibits alkali-silica reaction effectively.

  17. Linear Array Ultrasonic Test Results from Alkali-Silica Reaction (ASR) Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Dwight A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Khazanovich, Dr. Lev [Univ. of Minnesota, Minneapolis, MN (United States); Salles, Lucio [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-04-01

    The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.This report presents results of the ultrasound evaluation of four concrete slabs with varying levels of ASR damage present. This included an investigation of the experimental results, as well as a supplemental simulation considering the effect of ASR damage by elasto-dynamic wave propagation using a finite integration technique method. It was found that the Hilbert Transform Indicator (HTI), developed for quantification of freeze/thaw damage in concrete structures, could also be successfully utilized for quantification of ASR damage. internal microstructure flaws, and reinforcement locations.

  18. Linear Array Ultrasonic Test Results from Alkali-Silica Reaction (ASR) Specimens

    International Nuclear Information System (INIS)

    The purpose of the U.S. Department of Energy Office of Nuclear Energy's Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.This report presents results of the ultrasound evaluation of four concrete slabs with varying levels of ASR damage present. This included an investigation of the experimental results, as well as a supplemental simulation considering the effect of ASR damage by elasto-dynamic wave propagation using a finite integration technique method. It was found that the Hilbert Transform Indicator (HTI), developed for quantification of freeze/thaw damage in concrete structures, could also be successfully utilized for quantification of ASR damage. internal microstructure flaws, and reinforcement locations.

  19. Mecanismes d'action des fines et des granulats de verre sur la reaction alcali-silice et la reaction pouzzolanique

    Science.gov (United States)

    Idir, Rachida

    Recycling composite glass with different colours in order to be manufactured into new glass products is at present not economically viable. Therefore, the search for new issues other than stockpile areas or dumping sites could be a serious opportunity. To a certain extent, one of the possible solutions is to use the recycled glass in manufacturing cements and in the preparation of concrete mixtures. However, it is essential to manage the two main behaviours that the glass can have when used in cement-based materials: (1) the use of glass as coarse aggregates reveals harmful behaviour related to alkali-silica reaction; (2) on the other hand, it can result in useful behaviour related to pozzolanic reaction if used as fine particles. Furthermore, the significant alkali content should not be overlooked as their mass corresponds to about 13% of the total mass of the glass and as they may activate the alkali-silica reaction. An experimental programme was conducted to provide answers to the various questions raised about the use of glass in cement-based materials. The first part of this work was primarily devoted to the evaluation of the reactive potential of glass in mortars (alkali and pozzolanic reactions). At this stage, nine classes of glass particles ranging from 3mum to 2.5 mm were considered. Then, fine glass particles were used in order to counteract the negative effect of some classes of coarse aggregates having revealed alkali-reactive behaviour. The second part of this work was performed to study the mechanisms that could explain the behaviours of fine and coarse particles in aqueous and concentrated environments. Different answers have been proposed to explain the observed behaviour in terms of grain sizes of glass. Keywords: Glass, Powder, Pozzolan, aggregates, alkali-reaction, alkali-aggregate reaction, alkali-silica reaction, Pouzzolanicity, alkalis, Mortars

  20. Alcali-silica reactions: Mechanisms for crack formations

    DEFF Research Database (Denmark)

    Goltermann, Per

    2006-01-01

    Alkali-silica reactions (ASR) are found all over the world and cause a large number of damage, which have lead to different sets of requirements in the different countries for the aggregates, the cements and the admixtures. One of the reasons for the damage and the different requirements is that...

  1. Observed Infant Reactions during Live Interparental Conflict

    Science.gov (United States)

    Du Rocher Schudlich, Tina D.; White, Clare R.; Fleischhauer, Emily A.; Fitzgerald, Kelly A.

    2011-01-01

    Associations between interparental conflict and infant reactions were examined. Infants' history of exposure to interparental conflict and infant reactive temperament were examined as moderators. A community sample of 74 infants, aged 6-14 months, participated with their parents. Behavioral observations were made of parents' marital conflict and…

  2. An Experimental Study on Mitigating Alkali Silica Reaction by Using Fly Ash (FA) in Combination with Silica Fume and Expanded Perlite Powder (EPP)

    OpenAIRE

    Isneini Mohd; Sagawa Yasutaka; Hamada Hidenori; Yamamoto Daisuke

    2016-01-01

    ASR suppression by FA, SF, EPP, FA in combination with SF and EPP were evaluated by both mortar bar and concrete prism test. Mortar bars were made based on JIS A 1146, meanwhile concrete prism bars were casted in accordance with Rilem AAR-3. Both specimens were stored in 40°C 100% R.H. controlled room. Mortar and concrete mixtures used reactive aggregate in pessimum proportion. The results indicated that FA in combination with SF and EPP showed smaller expansion compared to FA. The best of co...

  3. An Experimental Study on Mitigating Alkali Silica Reaction by Using Fly Ash (FA in Combination with Silica Fume and Expanded Perlite Powder (EPP

    Directory of Open Access Journals (Sweden)

    Isneini Mohd

    2016-01-01

    Full Text Available ASR suppression by FA, SF, EPP, FA in combination with SF and EPP were evaluated by both mortar bar and concrete prism test. Mortar bars were made based on JIS A 1146, meanwhile concrete prism bars were casted in accordance with Rilem AAR-3. Both specimens were stored in 40°C 100% R.H. controlled room. Mortar and concrete mixtures used reactive aggregate in pessimum proportion. The results indicated that FA in combination with SF and EPP showed smaller expansion compared to FA. The best of concrete mixtures in reducing expansion is combination of FA with SF (FA15SF10.

  4. Observation of muon-electron pairs in neutrino reactions

    International Nuclear Information System (INIS)

    The present thesis describes the observation of muon-electron pairs in neutrino reactions. This experiment was performed using an optical multiplate spark chamber in the broad band neutrino beam of the CERN proton synchrotron. (orig.)

  5. Observation of Coherence in the Photosystem II Reaction Center

    CERN Document Server

    Fuller, Franklin D; Senlik, S Seckin; Wilcox, Daniel E; Ogilvie, Jennifer P

    2013-01-01

    Photosynthesis powers life on our planet. The basic photosynthetic architecture comprises antenna complexes to harvest solar energy and reaction centers to convert the energy into a stable charge separated state. In oxygenic photosynthesis, the initial charge separation event occurs in the photosystem II reaction center; the only known natural enzyme that uses solar energy to split water. Energy transfer and charge separation in photosynthesis are rapid and have high quantum efficiencies. Recently, nonlinear spectroscopic experiments have suggested that electronic coherence may play a role in energy transfer efficiency in antenna complexes. Here we report the observation of coherence in the photosystem II reaction center by two dimensional electronic spectroscopy. The frequencies of the observed coherences match exciton difference frequencies and/or known vibrational modes of the photosystem II reaction center. These observations raise questions about the possible role of electronic and/or vibrational coheren...

  6. Medium effects on spin observables of proton knockout reactions

    Energy Technology Data Exchange (ETDEWEB)

    Krein, G. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Maris, T.A.J.; Rodrigues, B.B.; Veit, E.A. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica

    1994-07-01

    Medium modifications of the properties of bound nucleons and mesons are investigated by means of medium energy quasi free proton knockout reactions with polarized incident protons. The sensitivity of the spin observables of these reactions to modifications of the nucleon and meson properties is studied using the Bonn one-boson exchange model of the nucleon-nucleon interaction. A method proposed to extract the pp analysing power in medium from the (p, 2 p) asymmetries indicates a reduction of this quantity compared to its free space value. This reduction is linked to modifications of masses and coupling constants of the nucleons and mesons in the nucleus. The implications of these modifications for another spin observable to be measured in the future are discussed. (author). 39 refs, 9 figs.

  7. [Measurements of observables of pion-nucleon reactions]. Progress report

    International Nuclear Information System (INIS)

    This document reports the progress of the research of pion reactions. These include (1) a study to measure observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross section measurements at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π+- on 3H and 3He. Individual experiments will be indexed separately

  8. Positivity constraints on initial spin observables in inclusive reactions.

    Science.gov (United States)

    Soffer, Jacques

    2003-08-29

    For any inclusive reaction of the type A1(spin 1/2)+A2(spin 1/2)-->B+X, we derive new positivity constraints on spin observables and study their implications for theoretical models in view, in particular, of accounting for future data from the polarized pp collider at Brookhaven RHIC. We find that the single transverse spin asymmetry A(N), in the central region for several processes, for example, jet production, direct photon production, and lepton-pair production, is expected to be such that |A(N)| < or approximately 1/2, rather than the usual bound |A(N)|< or =1.

  9. Observation of incomplete fusion reactions at l < l {sub crit}

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Abhishek, E-mail: abhishekyadav117@gmail.com; Sharma, Vijay R., E-mail: abhishekyadav117@gmail.com; Singh, Devendra P., E-mail: abhishekyadav117@gmail.com; Unnati,; Singh, B. P.; Prasad, R. [Department of Physics, Aligarh Muslim University, Aligarh (UP) - 202 002 (India); Singh, Pushpendra P. [GSI-Helmholtz Centre for Heavy Ion Research GmbH, D-64291 Darmstadt (Germany); Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P. [NP-Group: Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi - 110 067 (India); Sharma, M. K. [Department of Physics, S. V. College, Aligarh- 202 001 (India)

    2014-08-14

    In order to understand the presence of incomplete fusion at low energies i.e. 4-7MeV/nucleon and also to study its dependence on various entrance-channel parameters, the two type of measurements (i) excitation function for {sup 12}C+{sup 159}Tb, and (ii) forward recoil ranges for {sup 12}C+{sup 159}Tb systems have been performed. The experimentally measured excitation functions have been analyzed within the framework of compound nucleus decay using statistical model code PACE4. Analysis of data suggests the production of xn/px)n-channels via complete fusion, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of α-emitting channels has been observed over the theoretical ones, which has been attributed due to the incomplete fusion processes. Further, the incomplete fusion events observed in case of forward recoil range measurements have been explained on the basis of the breakup fusion model, where these events may be attributed to the fusion of {sup 8}Be and/or {sup 4}He from {sup 12}C projectile to the target nucleus. In the present work, the SUMRULE model calculations are found to highly underestimate the observed incomplete fusion cross-sections which indicate that the l-values lower than l {sub crit} (limit of complete fusion) significantly contribute to the incomplete fusion reactions.

  10. Staff Reactions to Challenging Behaviour: An Observation Study

    Science.gov (United States)

    Lambrechts, Greet; Van Den Noortgate, Wim; Eeman, Lieve; Maes, Bea

    2010-01-01

    Staff reactions play an important role in the development and maintaining of clients' challenging behaviour. Because there is a paucity of research on staff reactions in naturalistic settings, this study examined sequential associations between challenging behaviour and staff reactions by means of a descriptive analysis. We analysed video…

  11. A competitive reaction observed during fluorination of FHPG and FHBG

    International Nuclear Information System (INIS)

    The 18F-labelling yield of the tracers [18F]FHBG and [18F]FHPG, which is used to monitor the gene expression of HSV-1 TK, is reduced by competitive reactions. In the synthesis of the reference standards the by-products were isolated and analysed. (orig.)

  12. Use of mineral additions for the inhibition of internal expansive reactions in concrete structures : Good and bad synergies

    OpenAIRE

    Santos Silva, A.; BETTENCOURT RIBEIRO, A; Jalali, S; Divet, Loïc

    2008-01-01

    Several studies have been performed along the last few years related with the use of fly ash in the suppression of expansion due to alkali-silica reaction (ASR). However, relatively little attention has been focused in its effectiveness to control the delayed ettringite formation (DEF) in hardened concrete, and the use of metakaolin to control the ASR and DEF. The research work presented in this paper deals with the influence of fly ash (FA) and metakaolin (MK) in the inhibition of ASR and DE...

  13. Estimation of the reaction rate constant of HOCl by SMILES observation

    Science.gov (United States)

    Kuribayashi, Kouta; Kasai, Yasuko; Sato, Tomohiro; Sagawa, Hideo

    2012-07-01

    Hypochlorous acid, HOCl plays an important role to link the odd ClOx and the odd HOx in the atmospheric chemistry with the reaction: {ClO} + {HO_{2}} \\longrightarrow {HOCl} + {O_{2}} Quantitative understanding of the rate constant of the reaction (1.1) is essential for understanding the ozone loss in the mid-latitude region because of a view point of its rate controlling role in the ozone depletion chemistry. Reassessment of the reaction rate constant was pointed out from MIPAS/Envisat observations (von Clarmann et al., 2011) and balloon-borne observations (Kovalenko et al., 2007). Several laboratory studies had been reported, although the reaction rate constants have large uncertainties, as k{_{HOCl}} = (1.75 ± 0.52) × 10^{-12} exp[(368 ± 78)/T] (Hickson et al., 2007), and large discrepancies (Hickson et al., 2007;Stimpfle et al., 1979). Moreover, theoretical ab initio studies pointed out the pressure dependence of the reaction (1.1) (Xu et al., 2003). A new high-sensitive remote sensing technology named Superconducting SubMillimeter-wave Limb-Emission Sounder (SMILES) on the International Space Station (ISS) had observed diurnal variations of HOCl in the upper stratosphere/lower mesosphere (US/LM) region for the first time. ClO and HO_{2} were slso observed simultaneously with HOCl. SMILES performed the observations between 12^{{th}} October 2009 and 21^{{th}} April 2010. The latitude coverage of SMILES observation is normally 38°S-65°N. The altitude region of HOCl observation is about 28-70 km. We estimated the time period in which the reaction (1.1) becomes dominant in the ClO_{y} diurnal chemistry in US/LM. The reaction rate constant was directly estimated by decay of [ClO] and [HO_{2}] amounts in that period. The derived reaction rate constant represented well the increase of [HOCl] amount.

  14. Weight-Based Victimization toward Overweight Adolescents: Observations and Reactions of Peers

    Science.gov (United States)

    Puhl, Rebecca M.; Luedicke, Joerg; Heuer, Cheslea

    2011-01-01

    Background: Weight-based victimization has become increasingly reported among overweight youth, but little is known about adolescents' perceptions and observations of weight-based teasing and bullying. This study examined adolescents' observations of and reactions to weight-based victimization toward overweight students at school. Methods:…

  15. Observation of double pygmy resonances in $^{195,196}$Pt and enhanced astrophysical reaction rates

    CERN Document Server

    Giacoppo, F; Eriksen, T K; Görgen, A; Guttormsen, M; Hagen, T W; Larsen, A C; Kheswa, B V; Klintefjord, M; Koehler, P E; Nyhus, H T; Renstr\\om, T; Sahin, E; Siem, S; Tornyi, T G

    2014-01-01

    Our measurements of $^{195,196}$Pt $\\gamma$-strength functions show a double-humped enhancement in the $E_{\\gamma}= 4-8$ MeV region. For the first time, the detailed shape of these resonances is revealed for excitation energies in the quasicontinuum. We demonstrate that the corresponding neutron-capture cross sections and astrophysical reaction rates are increased by up to a factor of 2 when these newly observed pygmy resonances are included. These results lend credence to theoretical predictions of enhanced reaction rates due to such pygmy resonances and hence are important for a better understanding of r-process nucleosynthesis.

  16. A Luenberger observer for reaction-diffusion models with front position data

    Science.gov (United States)

    Collin, Annabelle; Chapelle, Dominique; Moireau, Philippe

    2015-11-01

    We propose a Luenberger observer for reaction-diffusion models with propagating front features, and for data associated with the location of the front over time. Such models are considered in various application fields, such as electrophysiology, wild-land fire propagation and tumor growth modeling. Drawing our inspiration from image processing methods, we start by proposing an observer for the eikonal-curvature equation that can be derived from the reaction-diffusion model by an asymptotic expansion. We then carry over this observer to the underlying reaction-diffusion equation by an "inverse asymptotic analysis", and we show that the associated correction in the dynamics has a stabilizing effect for the linearized estimation error. We also discuss the extension to joint state-parameter estimation by using the earlier-proposed ROUKF strategy. We then illustrate and assess our proposed observer method with test problems pertaining to electrophysiology modeling, including with a realistic model of cardiac atria. Our numerical trials show that state estimation is directly very effective with the proposed Luenberger observer, while specific strategies are needed to accurately perform parameter estimation - as is usual with Kalman filtering used in a nonlinear setting - and we demonstrate two such successful strategies.

  17. Real-time observations of lithium battery reactions-operando neutron diffraction analysis during practical operation.

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-01-01

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries. PMID:27357605

  18. Prospective Observational Study of Adverse Drug Reactions of Anticancer Drugs Used in Cancer Treatment in a Tertiary Care Hospital

    OpenAIRE

    V. K. Saini; Sewal, R. K.; Ahmad, Yusra; B Medhi

    2015-01-01

    Adverse drug reactions associated with the use of anticancer drugs are a worldwide problem and cannot be ignored. Adverse drug reactions can range from nausea, vomiting or any other mild reaction to severe myelosuppression. The study was planned to observe the suspected adverse drug reactions of cancer chemotherapy in patients aged >18 years having cancer attending Postgraduate Institute of Medical Education and Research, Chandigarh. During the study period, 101 patients of breast cancer and ...

  19. Observation of the Helium 7 {Lambda} hypernucleus by the (e,e'K+) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Satoshi; Okayasu, Yuichi; Seva, Tomislav; Rodriguez, Victor; Baturin, Pavlo; Yuan, Lulin; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, Oliver; Benmokhtar, Fatiha; Boeglin, Wener; Bosted, Peter; Carlini, Roger; Chen, Chunhua; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, Aji; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Toshiyuki, Gogami; Gueye, Paul; Han, Yuncheng; Hashimoto, Osamu; Hiyama, E; Honda, D; Horn, Tanja; Hu, Bitao; Hungerford, Ed; Jayalath, Chandana; Jones, Mark; Johnston, Kathleen; Kalantarians, Narbe; Kanda, Hiroki; Kaneta, M; Kato, Seigo; Kato, Shigeki; Kawama, Daisuke; Keppel, Cynthia; Kramer, Laird; Lan, Kejian; Luo, Wei; Mack, David; Maeda, Kazushige; Malace, Simona; Margaryan, Amur; Marikyan, Gagik; Markowitz, Pete; Maruta, Tomofumi; Maruyama, Nayuta; Miyoshi, Toshinuobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Nagao, Sho; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nonaka, Kenichi; Ohtani, Atsushi; Oyamada, Masamichi; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Raue, Brian; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Sato, Yoshinori; Segbefia, Edwin; Simicevic, Neven; Smith, Gregory; Song, Yushou; Sumihama, Mizuki; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tang, Liguang; Tsukada, Kyo; Tvaskis, Vladas; Vulcan, William; Wells, Steven; Wood, Stephen; Yan, Chen

    2013-01-01

    An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 {Lambda}, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The He 7 {Lambda} binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of {Lambda} N potential.

  20. Possible evidence of tensor interactions in 16O observed via (p,d) reaction

    CERN Document Server

    Ong, H J; Tamii, A; Myo, T; Ogata, K; Fukuda, M; Hirota, K; Ikeda, K; Ishikawa, D; Kawabata, T; Matsubara, H; Matsuta, K; Mihara, M; Naito, T; Nishimura, D; Ogawa, Y; Okamura, H; Ozawa, A; Pang, D Y; Sakaguchi, H; Sekiguchi, K; Suzuki, T; Taniguchi, M; Takashina, M; Toki, H; Yasuda, Y; Yosoi, M; Zenihiro, J

    2012-01-01

    We have measured 16O(p,d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on the effect of the tensor interactions in light nucleus. Differential cross sections of the one-neutron transfer reactions populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement for the positive-parity state(s). The observation indicates large components of high-momentum neutrons in the initial ground-state configurations, due possibly to the tensor interactions.

  1. Atomic-Scale Observations of Catalyst Structures under Reaction Conditions and during Catalysis.

    Science.gov (United States)

    Tao, Franklin Feng; Crozier, Peter A

    2016-03-23

    Heterogeneous catalysis is a chemical process performed at a solid-gas or solid-liquid interface. Direct participation of catalyst atoms in this chemical process determines the significance of the surface structure of a catalyst in a fundamental understanding of such a chemical process at a molecular level. High-pressure scanning tunneling microscopy (HP-STM) and environmental transmission electron microscopy (ETEM) have been used to observe catalyst structure in the last few decades. In this review, instrumentation for the two in situ/operando techniques and scientific findings on catalyst structures under reaction conditions and during catalysis are discussed with the following objectives: (1) to present the fundamental aspects of in situ/operando studies of catalysts; (2) to interpret the observed restructurings of catalyst and evolution of catalyst structures; (3) to explore how HP-STM and ETEM can be synergistically used to reveal structural details under reaction conditions and during catalysis; and (4) to discuss the future challenges and prospects of atomic-scale observation of catalysts in understanding of heterogeneous catalysis. This Review focuses on the development of HP-STM and ETEM, the in situ/operando characterizations of catalyst structures with them, and the integration of the two structural analytical techniques for fundamentally understanding catalysis.

  2. Nuclear-reaction studies via the observation of unbound outgoing systems

    Energy Technology Data Exchange (ETDEWEB)

    Bice, A.N.

    1982-01-01

    The mechanisms involved in the production of fast ..cap alpha..-particles in /sup 12/C induced reactions have been investigated for the /sup 12/C + /sup 208/Pb system at bombarding energies of E(/sup 12/C) = 132, 187 and 230 MeV. Absolute cross sections have been determined for the reactions /sup 208/Pb (/sup 12/C, /sup 8/Be (g.s.)), /sup 208/Pb(/sup 12/C, /sup 8/Be (2.94 MeV)) and /sup 208/Pb (/sup 12/C, /sup 12/C* ..-->.. ..cap alpha.. + /sup 8/Be) by double and triple coincidence measurements of the sequential decay ..cap alpha..-particles. Inclusive ..cap alpha..-particle production cross sections were also measured at E (/sup 12/C) = 187 MeV for comparison. It is found that the simple inelastic scattering process (/sup 12/C, /sup 12/C* ..-->.. ..cap alpha.. + /sup 8/Be) does not contribute significantly to the production of fast ..cap alpha..-particles but that the production of /sup 8/Be nuclei by projectile fragmentation is an important source of ..cap alpha..-particles. At the highest bombarding energy investigated (19 MeV/A) it appears that the /sup 12/C ..-->.. 3..cap alpha.. fragmentation reaction becomes more prominent at the expense of the /sup 12/C ..-->.. ..cap alpha.. + /sup 8/Be fragmentation channel. It is concluded that projectile spectroscopic properties and/or final state interactions are important in fragmentation reactions for these bombarding energies. In a kinematically complete experiment the direct and the sequential breakup channels of 10 MeV/A /sup 7/Li projectiles have been investigated with /sup 12/C and /sup 208/Pb targets. By appropriate arrangement of detector telescopes it was possible to define a kinematical window which allowed for the unambigious observation of both the direct (to the ..cap alpha..-t continuum) and the sequential components of a heavy-ion projectile breakup reaction. A semiclassical Monte Carlo type projectile breakup calculation was constructed which qualitatively reproduced the measured ..cap alpha

  3. Observations of parent reactions to sex-stereotyped behaviors: age and sex effects.

    Science.gov (United States)

    Fagot, B I; Hagan, R

    1991-06-01

    To examine differential socialization of boys and girls by mothers and fathers, home observations were completed for families of 92 12-month-old children, 82 18-month-old children, and 172 5-year-old children. Mothers gave more instructions and directions than did fathers, while fathers spent more time in positive play interaction. Differences in parents' reactions to 12- and 18-month boys and girls were as expected, with the exception that boys received more negative comment for communication attempts than did girls. The suggestion in the literature that fathers would be more involved in sex typing than mothers was not confirmed in this study. The only 2 significant sex-of-parent x sex-of-child effects occurred at 18 months; fathers gave fewer positive reactions to boys engaging in female-typical toy play, and mothers gave more instruction to girls when they attempted to communicate. We argue that the second year of life is the time when children are learning many new skills and when parents are still experimenting with parenting styles and may well use stereotypical responses when unsure of themselves.

  4. Evidence of tensor interactions in 16O observed via (p,d reaction

    Directory of Open Access Journals (Sweden)

    Ong H. J.

    2014-03-01

    Full Text Available We measured the differential cross sections of the 16O(p,d reaction populating the ground state and several low-lying excited states in 15O using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP, Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s. The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

  5. What happens when iron becomes wet? Observation of reactions at interfaces between liquid and metal surfaces

    CERN Document Server

    Kimura, M

    2003-01-01

    Synchrotron-radiation has been applied to investigation of interfaces between liquid and metal surfaces, with a special attention to corrosion. Three topics are shown: (1) nano structures of rusts formed on steel after atmospheric corrosion. Evolution of 'Fe(O, OH) sub 6 network' is the key to understand how the durable rusts prevent from formation of more rusts. (2) In situ observation of reactions at the interface has been carried out for localized corrosion of stainless steel. It is shown that change in states of Cr sup 3 sup + and Br sup - ions near the interface is deeply related with a breakout of the passivation film. (3) A structural phase transformation on a Cu sub 3 Au(001) surface was investigated. Ordering remains even at a temperature higher than the bulk-critical temperature, showing surface-induced ordering. These approaches gives us crucial information for a new steel-product. (author)

  6. Atomic-scale observation of lithiation reaction front in nanoscale SnO 2 materials

    KAUST Repository

    Nie, Anmin

    2013-07-23

    In the present work, taking advantage of aberration-corrected scanning transmission electron microscopy, we show that the dynamic lithiation process of anode materials can be revealed in an unprecedented resolution. Atomically resolved imaging of the lithiation process in SnO2 nanowires illustrated that the movement, reaction, and generation of b = [1Ì...1Ì...1] mixed dislocations leading the lithiated stripes effectively facilitated lithium-ion insertion into the crystalline interior. The geometric phase analysis and density functional theory simulations indicated that lithium ions initial preference to diffuse along the [001] direction in the {200} planes of SnO2 nanowires introduced the lattice expansion and such dislocation behaviors. At the later stages of lithiation, the Li-induced amorphization of rutile SnO2 and the formation of crystalline Sn and LixSn particles in the Li2O matrix were observed. © 2013 American Chemical Society.

  7. Evidence of tensor interactions in 16O observed via (p,d) reaction

    International Nuclear Information System (INIS)

    We measured the differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions. (authors)

  8. A systematic review of observational studies evaluating costs of adverse drug reactions

    Directory of Open Access Journals (Sweden)

    Batel Marques F

    2016-08-01

    Full Text Available Francisco Batel Marques,1,2 Ana Penedones,1,2 Diogo Mendes,1,2 Carlos Alves,1,2 1CHAD – Centre for Health Technology Assessment and Drug Research, AIBILI – Association for Innovation and Biomedical Research on Light and Image, 2School of Pharmacy, University of Coimbra, Coimbra, Portugal Introduction: The growing evidence of the increased frequency and severity of adverse drug events (ADEs, besides the negative impact on patient’s health status, indicates that costs due to ADEs may be steadily rising. Observational studies are an important tool in pharmacovigilance. Despite these studies being more susceptible to bias than experimental designs, they are more competent in assessing ADEs and their associated costs.Objective: To identify and characterize the best available evidence on ADE-associated costs.Methods: MEDLINE, Cochrane Library, and Embase were searched from 1995 to 2015. Observational studies were included. The methodological quality of selected studies was assessed by Cochrane Collaboration tool for experimental and observational studies. Studies were classified according to the setting analyzed in “ambulatory”, “hospital”, or both. Costs were classified as “direct” and “indirect”. Data were analyzed using descriptive statistics. The total incremental cost per patient with ADE was estimated.Results: Twenty-nine (94% longitudinal observational studies and two (7% cross-sectional studies were included. Twenty-three (74% studies were assessed with the highest methodological quality score. The studies were mainly conducted in the US (61%. Twenty (65% studies evaluated any therapeutic group. Twenty (65% studies estimated costs of ADEs leading to or prolonging hospitalization. The “direct costs” were evaluated in all studies, whereas only two (7% also estimated the “indirect costs”. The “direct costs” in ambulatory ranged from €702.21 to €40,273.08, and the in hospital from €943.40 to €7

  9. In situ observation of the reaction of scandium and carbon by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Arellano, Erick A., E-mail: eajuarez@unpa.edu.m [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Winkler, Bjorn [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Vogel, Sven C. [Los Alamos National Laboratory, Lujan Center. Mail Stop H805, Los Alamos, NM 87545 (United States); Senyshyn, Anatoliy [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, Lichtenbergstr. 1, D-85747 Garching (Germany); Materialwissenschaft, TU Darmstadt, Petersensstr. 23, D-64287 Darmstadt (Germany); Kammler, Daniel R. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Avalos-Borja, Miguel [CNyN, UNAM, A. Postal 2681, Ensenada, B.C. (Mexico)

    2011-01-05

    Research highlights: {yields} Exist two ScC cubic phases with B1-structure type differing in site occupancy of C. {yields} A new orthorhombic scandium carbide phase is formed at 1473(50) K. {yields} The recrystallization of alpha-Sc occurs between 1000 and 1223 K. - Abstract: The formation of scandium carbides by reaction of the elements has been investigated by in situ neutron diffraction up to 1823 K. On heating, the recrystallization of {alpha}-Sc occurs between 1000 and 1223 K. The formation of Sc{sub 2}C and ScC (NaCl-B1 type structure) phases has been detected at 1323 and 1373 K, respectively. The formation of a new orthorhombic scandium carbide phase was observed at 1473(50) K. Once the scandium carbides are formed they are stable upon heating or cooling. No other phases were detected in the present study, in which the system was always carbon saturated. The thermal expansion coefficients of all phases have been determined, they are constant throughout the temperature interval studied.

  10. Observation of the one- to six-neutron transfer reactions at sub-barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C.L.; Rehm, K.E.; Gehring, J. [and others

    1995-08-01

    It was suggested many years ago that when two heavy nuclei are in contact during a grazing collision, the transfer of several correlated neutron-pairs could occur. Despite considerable experimental effort, however, so far only cross sections for up to four-neutron transfers have been uniquely identified. The main difficulties in the study of multi-neutron transfer reactions are the small cross sections encountered at incident energies close to the barrier, and various experimental uncertainties which can complicate the analysis of these reactions. We have for the first time found evidence for multi-neutron transfer reactions covering the full sequence from one- to six-neutron transfer reactions at sub-barrier energies in the system {sup 58}Ni + {sup 100}Mo.

  11. In situ observation of surface species on iridium oxide nanoparticles during the oxygen evolution reaction

    OpenAIRE

    KAYA, Sarp; Casalongue, Hernan G. Sanchez; Ng, May Ling; Friebel, Daniel; Ogasawara, Hirohito; Nilsson, Anders

    2014-01-01

    An iridium oxide nanoparticle electrocatalyst under oxygen evolution reaction conditions was probed in situ by ambient-pressure X-ray photoelectron spectroscopy. Under OER conditions, iridium undergoes a change in oxidation state from Ir-IV to Ir-V that takes place predominantly at the surface of the catalyst. The chemical change in iridium is coupled to a decrease in surface hydroxide, providing experimental evidence which strongly suggests that the oxygen evolution reaction on iridium oxide...

  12. Rate Constant Change of Photo Reaction of Bacteriorhodopsin Observed in Trimeric Molecular System.

    Science.gov (United States)

    Tsujiuchi, Yutaka; Masumoto, Hiroshi; Goto, Takashi

    2016-04-01

    To elucidate the time evolution of photo reaction of bacteriorhodopsin in glycerol mixed purple membrane at around 196 K under irradiation by red light, a kinetic model was constructed. The change of absorption with irradiation at times of 560 nm and 412 nm was analyzed for the purpose of determining reaction rates of photo reaction of bacteriorhodopsin and its product M intermediate. In this study it is shown that reaction rates of conversion from bacteriorhodopsin to the M intermediate can be explained by a set of linear differential equations. This model analysis concludes that bacteriorhodopsin in which constitutes a trimer unit with other two bacteriorhodopsin molecules changes into M intermediates in the 1.73 of reaction rate, in the initial step, and according to the number of M intermediate in a trimer unit, from three to one, the reaction rate of bacteriorhodopsin into M intermediates smaller as 1.73, 0.80, 0.19 which caused by influence of inter-molecular interaction between bacteriorhodopsin. PMID:27451646

  13. Polarization observables in the e{sup +}e{sup -} → anti ΛΛ reaction

    Energy Technology Data Exchange (ETDEWEB)

    Faeldt, Goeran [Uppsala University, Department of physics and astronomy, Box 516, Uppsala (Sweden)

    2016-05-15

    Cross-section, vector-polarization, and tensor-polarization distributions are calculated for the reactions e{sup +}e{sup -}→ anti pp and e{sup +}e{sup -}→ anti ΛΛ. Each reaction requires six characteristic functions that are bilinear in the, possibly complex, electromagnetic form factors, denoted G{sub E}(P{sup 2}) and G{sub M}(P{sup 2}), of p and Λ. For the hyperon reaction also the joint-decay distributions of Λ and anti Λ are calculated. Their knowledge allows a complete determination of the hyperon electromagnetic form factors, without measuring hyperon spins. We explain how this is done in practice. For some tensor-polarization components our results are in conflict with previously repeatedly published distributions. (orig.)

  14. Low-energy resonances in the 22Ne(p,γ23Na reaction directly observed at LUNA

    Directory of Open Access Journals (Sweden)

    Cavanna Francesca

    2015-01-01

    A study of this reaction has been carried out at the Laboratory for Underground Nuclear Astrophysics (LUNA, in the Gran Sasso National Laboratory, using a windowless gas target and two high-purity germanium detectors. Several resonances have been observed for the first time in a direct experiment.

  15. The reaction 13C(alpha,n)16O: a background for the observation of geo-neutrinos

    OpenAIRE

    Harissopulos, S.; Becker, H. W.; Hammer, J. W.; Lagoyannis, A.; Rolfs, C.; Strieder, F

    2005-01-01

    The absolute cross section of the $^{13}$C($\\alpha$,n)$^{16}$O reaction has been measured at E$_{\\alpha}$ = 0.8 to 8.0 MeV with an overall accuracy of 4%. The precision is needed to subtract reliably a background in the observation of geo-neutrinos, e.g. in the KamLAND detector.

  16. Direct observations of reaction zone structure in shock-induced ignition of methane air mixture

    Institute of Scientific and Technical Information of China (English)

    WANG GaoFeng; MA ChengBiao; WANG BaoYuan; LIN QiZhao

    2009-01-01

    Ignition of methane/air mixture by the passage of a shock wave is an important issue for understanding more details of its gaseous detonation.The experiments of shock-induced ignition of stoichiometric methane/air mixture were conducted on a shock tube platform.The reaction zone structure in weak and strong ignition cases were investigated by digital chemiluminescence imaging and planar laser induced fluorescence (PLIF) techniques.Due to smaller gradients in induced time in weak ignition,which provided more time to nonlinear chemical reaction process,the results show that the reaction structures are highly nonuniform in those weak ignition cases,which become more regular while induced shock waves become stronger.In strong ignition case,it gives a typical detonation structure.The characteristics of reaction zone released by single-pulsed OH PLIF technique agreed well with other experimental measurements in this paper and were also in accord with the conclusions of previous researches.The successful implementation of the PLIF system has explored a new high temporally and spatially resolved method for the study of interaction between shock wave and gaseous matter in shock tube.

  17. Fenton reaction induced cancer in wild type rats recapitulates genomic alterations observed in human cancer.

    Directory of Open Access Journals (Sweden)

    Shinya Akatsuka

    Full Text Available Iron overload has been associated with carcinogenesis in humans. Intraperitoneal administration of ferric nitrilotriacetate initiates a Fenton reaction in renal proximal tubules of rodents that ultimately leads to a high incidence of renal cell carcinoma (RCC after repeated treatments. We performed high-resolution microarray comparative genomic hybridization to identify characteristics in the genomic profiles of this oxidative stress-induced rat RCCs. The results revealed extensive large-scale genomic alterations with a preference for deletions. Deletions and amplifications were numerous and sometimes fragmented, demonstrating that a Fenton reaction is a cause of such genomic alterations in vivo. Frequency plotting indicated that two of the most commonly altered loci corresponded to a Cdkn2a/2b deletion and a Met amplification. Tumor sizes were proportionally associated with Met expression and/or amplification, and clustering analysis confirmed our results. Furthermore, we developed a procedure to compare whole genomic patterns of the copy number alterations among different species based on chromosomal syntenic relationship. Patterns of the rat RCCs showed the strongest similarity to the human RCCs among five types of human cancers, followed by human malignant mesothelioma, an iron overload-associated cancer. Therefore, an iron-dependent Fenton chemical reaction causes large-scale genomic alterations during carcinogenesis, which may result in distinct genomic profiles. Based on the characteristics of extensive genome alterations in human cancer, our results suggest that this chemical reaction may play a major role during human carcinogenesis.

  18. Consistency between the monopole strength of the Hoyle state determined by structural calculation and that extracted from reaction observables

    CERN Document Server

    Minomo, Kosho

    2016-01-01

    We analyze the $\\alpha$-$^{12}$C inelastic scattering to the $0^+_2$ state of $^{12}$C, the Hoyle state, in a fully microscopic framework. With no free adjustable parameter, the inelastic cross sections at forward angles are well reproduced by the microscopic reaction calculation using the transition density of $^{12}$C obtained by the resonating group method and the nucleon-nucleon $g$ matrix interaction developed by the Melbourne group. It is thus shown that the monopole transition strength obtained by the structural calculation is consistent with that extracted from the reaction observable, suggesting no missing monopole strength of the Hoyle state.

  19. Chemotherapy-induced adverse drug reactions in oncology patients: A prospective observational survey

    OpenAIRE

    Deepti Chopra; Rehan, Harmeet S.; Vibha Sharma; Ritu Mishra

    2016-01-01

    Background: Chemotherapy, a multimodal approach to oncological treatment, involves highly complex regimens and hence accounts to high susceptibility toward adverse drug reactions (ADRs). The present study aims to determine the prevalence of adverse events in patients treated with chemotherapy. Materials and Methods: Spontaneous ADR report of patients on antineoplastic drugs received in the past 2 years (January 2011-January 2013) were studied. These reports were analyzed for various carcinoma...

  20. An Allergic Reaction (Anaphylaxis) Observed Before Open Heart Surgery in the Operating Room

    OpenAIRE

    Altın, Fırat; Aydın, Selim; Eygi, Börteçin; Güneş, Tevfik; Erkoç, Kamuran; Kutas, Barış

    2012-01-01

    Anaphylaxis and anaphylactoid reactions under general anesthesia are serious events and are often regarded as life threatening situations. A 57-year-old woman was admitted to cardiothora-cic surgery clinic for coronary artery by-pass grafting procedure with a diagnosis of coronary artery disease following a diagnostic coronary artery angiography. Upon arrival to the operating room, after necessary monitoring, general anesthesia was administered. Sterile placement of a central venous catheter ...

  1. Observation of Spontaneous C=C Bond Breaking in the Reaction between Atomic Boron and Ethylene in Solid Neon.

    Science.gov (United States)

    Jian, Jiwen; Lin, Hailu; Luo, Mingbiao; Chen, Mohua; Zhou, Mingfei

    2016-07-11

    A ground-state boron atom inserts into the C=C bond of ethylene to spontaneously form the allene-like compound H2 CBCH2 on annealing in solid neon. This compound can further isomerize to the propyne-like HCBCH3 isomer under UV light excitation. The observation of this unique spontaneous C=C bond insertion reaction is consistent with theoretical predictions that the reaction is thermodynamically exothermic and kinetically facile. This work demonstrates that the stronger C=C bond, rather than the less inert C-H bond, can be broken to form organoboron species from the reaction of a boron atom with ethylene even at cryogenic temperatures.

  2. Observation of Λ-hypernuclei in the reaction 12C(π+,K+)/sub Λ/12C

    International Nuclear Information System (INIS)

    The observation of Λ-hypernuclear levels in /sub Λ/12C by associated production through the (π+,K+) reaction is reported. Spectrometers used in the measurements are discussed. The /sub Λ/12C excitation energy spectra were recorded at laboratory scattering angles of 5.60, 10.30, and 15.20. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup π/ = 2+ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (π+,K+) reaction, compared to the (K-,π-) reaction in which lower spin states are excited. 29 refs., 40 figs

  3. Observation of Spontaneous C=C Bond Breaking in the Reaction between Atomic Boron and Ethylene in Solid Neon.

    Science.gov (United States)

    Jian, Jiwen; Lin, Hailu; Luo, Mingbiao; Chen, Mohua; Zhou, Mingfei

    2016-07-11

    A ground-state boron atom inserts into the C=C bond of ethylene to spontaneously form the allene-like compound H2 CBCH2 on annealing in solid neon. This compound can further isomerize to the propyne-like HCBCH3 isomer under UV light excitation. The observation of this unique spontaneous C=C bond insertion reaction is consistent with theoretical predictions that the reaction is thermodynamically exothermic and kinetically facile. This work demonstrates that the stronger C=C bond, rather than the less inert C-H bond, can be broken to form organoboron species from the reaction of a boron atom with ethylene even at cryogenic temperatures. PMID:27240114

  4. Ionic Debye Screening in Dense Liquid Plasmas Observed for Li+p,d Reactions with Liquid Li Target

    Institute of Scientific and Technical Information of China (English)

    J.Kasagi; H.Yonemura; Y.Toriyabe; A.Nakagawa; T.Sugawara; WANG Tie-shan

    2009-01-01

    Thick target yields of a particles emitted in the ~6Li(d,a)~4 He and ~7Li(p,a)~4 He reactions were measured for Li target in the solid and liquid phase.Observed reaction rates for the liquid Li are always larger than those for the solid.This suggests that the stopping power of hydrogen ion in the liquid Li metal might be smaller than in the solid.Using the empirically obtained stopping power for the liquid Li,we have deduced the screening potentials of the Li+p and Li+d reactions in both phases.The deduced screening potential for the liquid Li is about 500 eV larger than for the solid.This difference is attributed to the effect of liquefied Li~+ ions.It is concluded that the ionic screening is much stronger than the electronic screening in a low-temperature dense plasmas.

  5. Observation of. lambda. -hypernuclei in the reaction /sup 12/C(. pi. /sup +/,K/sup +/)/sub. lambda. //sup 12/C

    Energy Technology Data Exchange (ETDEWEB)

    Milner, E.C.

    1985-12-01

    The observation of ..lambda..-hypernuclear levels in /sub ..lambda..//sup 12/C by associated production through the (..pi../sup +/,K/sup +/) reaction is reported. Spectrometers used in the measurements are discussed. The /sub ..lambda..//sup 12/C excitation energy spectra were recorded at laboratory scattering angles of 5.6/sup 0/, 10.3/sup 0/, and 15.2/sup 0/. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup ..pi../ = 2/sup +/ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (..pi../sup +/,K/sup +/) reaction, compared to the (K/sup -/,..pi../sup -/) reaction in which lower spin states are excited. 29 refs., 40 figs.

  6. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaka, Masanari, E-mail: nagasaka@ims.ac.jp; Kosugi, Nobuhiro [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585 (Japan); Yuzawa, Hayato; Horigome, Toshio [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan)

    2014-10-15

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates.

  7. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    Science.gov (United States)

    Nagasaka, Masanari; Yuzawa, Hayato; Horigome, Toshio; Kosugi, Nobuhiro

    2014-10-01

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates.

  8. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    International Nuclear Information System (INIS)

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates

  9. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method.

    Science.gov (United States)

    Nagasaka, Masanari; Yuzawa, Hayato; Horigome, Toshio; Kosugi, Nobuhiro

    2014-10-01

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates. PMID:25362423

  10. Energy dependence of hadronic observables in central Pb+Pb reactions at the CERN SPS

    CERN Document Server

    Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncic, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Darmenov, N; Dimitrov, A; Dinkelaker, P; Eckardt, V; Farantatos, G; Flierl, D; Fodor, Z; Foka, P; Freund, P; Friese, V; Gál, J; Gazdzicki, M; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kliemant, M; Kniege, S; Kolesnikov, V I; Kollegger, T; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Markert, C; Mateev, M; Mayes, B W; Melkumov, G L; Meurer, C; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R; Richard, A; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Stefanek, C; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Yoo, I K; Zaranek, J; Zimányi, J

    2005-01-01

    In this contribution the energy dependence of various hadronic observables as measured by the NA49 experiment in the beam energy range between 20 and 158 AGeV is presented. These include m/sub t/ and rapidity distributions, particle ratio fluctuations, as well as HBT radii. The data are put in the context of results from the AGS and RHIC.

  11. Few-body nuclear reactions at low energies – an investigation on observed anomalies

    International Nuclear Information System (INIS)

    Few-body aspects of nuclear interaction are expected to be best studied at sufficiently lower energies where various pair-wise interactions overlap effectively with one another in the allowed phase space in kinematically complete configuration. In this direction, next to nucleon-deuteron systems, a very powerful testing ground has been the alpha-deuteron system where the alpha particle could be treated as a structureless boson due to its very high binding energy. The aim of the present work is to examine the strong anomalies observed in explaining the kinematically complete experimental observables in the light of Faddeev theoretical calculations (FT) due to Koike, involving alpha-induced break-up of deuterons at comparatively lower energies, ranging from Eα(inc)=11 to 18 MeV

  12. Observation of the reaction γγ->panti pπ+π-

    International Nuclear Information System (INIS)

    Production of the panti pπ+π- final state by two photon scattering was observed. The cross section for γγ->panti pπ+π- was determined assuming phase space production. No evidence was found for the production or formation of resonances. Upper limits are given for Λ and Δ pair production, for production of panti prho0 and for the two photon excitation of canti c bound states. (orig.)

  13. Chemotherapy-induced adverse drug reactions in oncology patients: A prospective observational survey

    Directory of Open Access Journals (Sweden)

    Deepti Chopra

    2016-01-01

    Full Text Available Background: Chemotherapy, a multimodal approach to oncological treatment, involves highly complex regimens and hence accounts to high susceptibility toward adverse drug reactions (ADRs. The present study aims to determine the prevalence of adverse events in patients treated with chemotherapy. Materials and Methods: Spontaneous ADR report of patients on antineoplastic drugs received in the past 2 years (January 2011-January 2013 were studied. These reports were analyzed for various carcinomas under treatment, medications used, types of ADRs, organ system involvement, severity, causality assessment, and preventability. Results: Over a period of 2 years, a total 591 cases were received with an incidence of 58.6%. The prevalence of ADRs was more in female patients (73.6% as compared to men. ADRs mostly occurred in the age group of 41-50 years (27.4%. Patients treated for breast carcinoma (39.1% reported the highest incidence of ADRs. Cisplatin (19.6% was found to be the most common offending drug. The most common ADR reported was nausea and vomiting (23%. Gastroenterology (40.1% was the most affected system. About 50.2% of the ADRs required treatment and 12.9% ADRs were considered serious. Causality assessment revealed that 80% of the ADRs were possible. About 86.97% cases were found to be mild, and 51% were not preventable. Conclusion: The success of chemotherapy comes with the word of caution regarding toxicities of antineoplastic drugs. Pharmacovigilance of these drugs needs to be explored, and use of preventative measures needs to be enhanced in order to reduce the incidence and severity of ADRs.

  14. Removing flow backgrounds from the charge-separation observable perpendicular to the reaction plane in heavy-ion collisions

    CERN Document Server

    Wen, Fufang; Wang, Gang

    2016-01-01

    Recent charge-dependent azimuthal correlation measurements in high-energy heavy-ion collisions have observed charge-separation signals perpendicular to the reaction plane, and the observations have been related to the chiral magnetic effect (CME). However, the correlation signal is contaminated with the background contributions due to the collective motion (flow) of the collision system, and it remains elusive to effectively remove the background from the correlation. We present a method study with Monte Carlo simulations and a multi-phase transport model, and develop a scheme to reveal the true CME signal via the event-shape engineering with the flow vector, $\\overrightarrow{q}$. An alternative approach using the ensemble averages of observables is also discussed.

  15. Observation of low-lying resonances in the quasicontinuum of 195,196Pt and enhanced astrophysical reaction rates

    Directory of Open Access Journals (Sweden)

    Giacoppo F.

    2015-01-01

    Full Text Available An excess of strength on the low-energy tail of the giant dipole resonance recently has been observed in the γ-decay from the quasicontinuum of 195,196Pt. The nature of this phenomenon is not yet fully investigated. If this feature is present also in the γ-ray strength of the neutron-rich isotopes, it can affect the neutron-capture reactions involved in the formation of heavy-elements in stellar nucleosynthesis. The experimental level density and γ-ray strength function of 195,196Pt are presented together with preliminary calculations of the corresponding neutron-capture cross sections.

  16. Measurement of beam-recoil observables Ox, Oz and target asymmetry for the reaction gamma p -> K Lambda

    CERN Document Server

    Llères, A

    2008-01-01

    The double polarization (beam-recoil) observables Ox and Oz have been measured for the reaction gamma p -> K Lambda from threshold production to Egamma = 1500 MeV. The data were obtained with the linearly polarized beam of the GRAAL facility. Values for the target asymmetry T could also be extracted despite the use of an unpolarized target. Analyses of our results by two isobar models tend to confirm the necessity to include new or poorly known resonances in the 1900 MeV mass region.

  17. Effect of viscosity on photoinduced electron transfer reaction: An observation of the Marcus inverted region in homogeneous solvents

    Science.gov (United States)

    Saini, Rajesh Kumar; Kuchlyan, Jagannath; Sarkar, Nilmoni

    2016-09-01

    The viscosity effect of homogeneous solvents on the dynamics of photoinduced electron transfer (PET) reaction among the coumarins and N,N-dimethylaniline (DMA) is investigated using steady-state and time-resolved fluorescence spectroscopy. A bell shape Marcus inversion in the ET rates has been detected in the plot of ET rate constant (kq) with free energy change (ΔG0) in viscous solvents decanol and EG, but it is not observed in DMSO like low viscous solvent. We have also reported that there is no complex formation between the coumarin dye and DMA molecule by using fluorescence correlation spectroscopy.

  18. Construction of the undulator beamline equipped with a UHV-STM for observations of synchrotron-radiation-stimulated surface reaction

    International Nuclear Information System (INIS)

    An undulator beamline equipped with a UHV-scanning tunneling electron microscopy (STM) system has been designed and constructed at the UVSOR facility to investigate synchrotron-radiation-stimulated reactions. Using this undulator beamline, we have observed irradiation effects on the hydrogen terminated-(H-) Si(1 1 1) surfaces in atomic scale. The small protrusions, which are assigned to the rest-atom with missing H, appeared on the monohydride surface after irradiation. The density of them monotonically increased with irradiation dose. This phenomenon has been observed almost independent on the Si 2p core electron excitation threshold, indicating the significant contribution of the valence electron excitations to the Si-H bond dissociations

  19. Does slow energy transfer limit the observed time constant for radical pair formation in photosystem II reaction centers?

    Science.gov (United States)

    Rech, T; Durrant, J R; Joseph, D M; Barber, J; Porter, G; Klug, D R

    1994-12-13

    We have used spectrally photoselective femtosecond transient absorption spectroscopy on photosystem II reaction centers to show that there are at least two pools of chlorin molecules/states which can transfer excitation energy to P680, the primary electron donor in photosystem II. It has previously been shown that one chlorin pool equilibrates with P680 in 100 fs [Durrant et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 11632-11636], and we report here the observation of energy transfer from a second more weakly coupled chlorin pool. The effect of the weakly coupled pool is to increase the apparent time constant for radical pair formation from 21 ps when P680 is selectively excited to 27 ps when the accessory chlorins are excited. We conclude that it is possible to observe both radical pair formation somewhat slowed by an energy transfer step and radical pair formation not limited by this slow energy transfer, depending upon which chromophores are initially excited. These observations provide evidence that when using photoselective excitation of P680, the observed 21 ps time constant for radical pair formation is not limited by a slow energy transfer step. PMID:7993905

  20. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  1. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    Directory of Open Access Journals (Sweden)

    C. S. McNaughton

    2009-03-01

    reduced to <50% of total nitrate (nitric acid plus particulate nitrate. NOy as a fraction of total nitrogen (NOy plus particulate nitrate, is reduced from >85% to 60–80% in the presence of dust. These observations support previous model studies which predict irreversible sequestration of reactive nitrogen species through heterogeneous reactions with mineral dust during long-range transport.

  2. A PROSPECTIVE, OBSERVATIONAL STUDY OF ADVERSE REACTIONS TO DRUG REGIME FOR MULTI-DRUG RESISTANT PULMONARY TUBERCULOSIS IN CENTRAL INDIA.

    Directory of Open Access Journals (Sweden)

    Dr. Rohan C. Hire

    2014-09-01

    Full Text Available Abstract Objective: 1 To assess the adverse drug reactions of second line anti-tubercular drugs used to treat Multi-drug resistant Tuberculosis (MDR TB in central India on the basis of causality, severity and avoidability scales. 2 To study the relationship of type of MDR TB (primary or secondary and presence of diabetes mellitus (DM with mean smear conversion time. Material and Methods: A prospective, observational study was carried out on diagnosed multidrug resistant tuberculosis patients enrolled for DOTS‑Plus regimen at TB and Chest Disease Department from January to December 2012. They were followed for 9 months thereafter and encountered adverse drug reactions (ADRs were noted along with the time of sputum conversion. The data were analysed by Chi-square or Fisher’s exact test and unpaired student’s‘t’ test. Results: Total 64 ADRs were reported in 55 patients out of total 110 patients (n = 110. As per the Naranjo causality assessment of ADRs, 7 patients had “definite” causal relation, 45 had “probable” causal relation and 3 had “possible” causal relation with drugs of DOTS Plus regime. As per the Hartwig’s severity assessment scale, there were total 7 ADRs in Level 1, 6 in Level 2, 33 in Level 3 and 9 in Level 4. Hallas avoidability assessment scale divided the ADRs as 3 being “Definitely avoidable”, 26 “Possibly avoidable”, 23 “Not avoidable” and 3 “unevaluable”. . Mean sputum smear conversion time is significantly higher in patients with secondary type than that of primary type of MDR TB (p = 0.0001 and in patients with DM than those without DM (p <0.0001. Conclusion: ADRs were common in patients of MDR TB on DOTs-Plus drug regime. It was due to lack of availability of safer and equally potent drugs in DOTs-Plus drug regime compared to DOTS regime in non-resistant TB. The frequency and severity of ADRs can be reduced by strict vigilance about known and unknown ADRs, monitoring their laboratory and

  3. Velocity-space observation regions of high-resolution two-step reaction gamma-ray spectroscopy

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nocente, M.; Gorini, G.;

    2015-01-01

    as an example. The energy-dependent cross sections of this reaction suggest that GRS is sensitive to alpha particles above about 1.7 MeV and highly sensitive to alpha particles at the resonance energies of the reaction. Here we demonstrate that highresolution two-step reaction GRS measurements are not only......High-resolution γ-ray spectroscopy (GRS) measurements resolve spectral shapes of Dopplerbroadened γ-rays. We calculate weight functions describing velocity-space sensitivities of any two-step reaction GRS measurements in magnetized plasmas using the resonant nuclear reaction 9Be(α, nγ)12C...

  4. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    Directory of Open Access Journals (Sweden)

    F. Flocke

    2009-11-01

    the submicrometer aerosol has a much larger effect on aerosol optical properties than changes to the hygroscopic:hydrophobic mass fractions of the accumulation mode aerosol.

    In the presence of dust, nitric acid concentrations are reduced to <50% of total nitrate (nitric acid plus particulate nitrate. NOy as a fraction of total nitrogen (NOy plus particulate nitrate, is reduced from >85% to 60–80% in the presence of dust. These observations support previous model studies which predict irreversible sequestration of reactive nitrogen species through heterogeneous reactions with mineral dust during long-range transport.

  5. Observation of stable HO4(+) and DO4(+) ions from ion-molecule reactions in helium nanodroplets.

    Science.gov (United States)

    Renzler, Michael; Ralser, Stefan; Kranabetter, Lorenz; Barwa, Erik; Scheier, Paul; Ellis, Andrew M

    2016-05-21

    Ion-molecule reactions between clusters of H2/D2 and O2 in liquid helium nanodroplets were initiated by electron-induced ionization (at 70 eV). Reaction products were detected by mass spectrometry and can be explained by a primary reaction channel involving proton transfer from H3(+) or H3(+)(H2)n clusters and their deuterated equivalents. Very little HO2(+) is seen from the reaction of H3(+) with O2, which is attributed to an efficient secondary reaction between HO2(+) and H2. On the other hand HO4(+) is the most abundant product from the reaction of H3(+) with oxygen dimer, (O2)2. The experimental data suggest that HO4(+) is a particularly stable ion and this is consistent with recent theoretical studies of this ion. PMID:27140863

  6. Observation of a chemically labile, noncovalent enzyme intermediate in the reaction of metal-dependent Aquifex pyrophilus KDO8PS by time-resolved mass spectrometry

    OpenAIRE

    Roberts, Anne; Furdui, Cristina; Anderson, Karen S.

    2010-01-01

    The direct detection of intermediates in enzymatic reactions can yield important mechanistic insights but may be difficult due to short intermediate lifetimes and chemical instability. Using a rapid-mixing device coupled with electrospray ionization time-of-flight mass spectrometry, the noncova-lent hemiketal intermediate in the reaction of metal-dependent 3-deoxy-D-manno-octulosonate-8-phosphate (KDO8P) synthase from Aquifex pyrophilus was observed in the millisecond time range. Using single...

  7. Contribution a la caracterisation des betons endommages par des methodes de l'acoustique non lineaire. Application a la reaction alcalis-silice

    Science.gov (United States)

    Kodjo, Apedovi

    The aim of this thesis is to contribute to the non-destructive characterization of concrete materials damaged by alkali-silica reaction (ASR). For this purpose, some nonlinear characterization techniques have been developed, as well as a nonlinear resonance test device. In order to optimize the sensitivity of the test device, the excitation module and signal processing have been improved. The nonlinear tests were conducted on seven samples of concrete damaged by ASR, three samples of concrete damaged by heat, three concrete samples damaged mechanically and three sound concrete samples. Since, nonlinear behaviour of the material is often attribute to its micro-defects hysteretic behaviour, it was shown at first that concrete damaged by ASR exhibits an hysteresis behaviour. To conduct this study, an acoustoelastic test was set, and then nonlinear resonance test device was used for characterizing sound concrete and concrete damaged by ASR. It was shown that the nonlinear technique can be used for characterizing the material without knowing its initial state, and also for detecting early damage in the reactive material. Studies were also carried out on the effect of moisture regarding the nonlinear parameters; they allowed understanding the low values of nonlinear parameters measured on concrete samples that were kept in high moisture conditions. In order to find a specific characteristic of damage caused by ASR, the viscosity of ASR gel was used. An approach, based on static creep analysis, performed on the material, while applying the nonlinear resonance technique. The spring-damping model of Maxwell was used for the interpretation of the results. Then, the creep time was analysed on samples damaged by ASR. It appears that the ASR gel increases the creep time. Finally, the limitations of the nonlinear resonance technique for in situ application have been explained and a new applicable nonlinear technique was initiated. This technique use an external source such as a

  8. In situ observation of RedOx reactions of Pd/Sr-Fe-O catalysts for automotive emission

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, M; Uemura, K; Nagai, T [Advanced Technology Research Laboratories, Nippon Steel Corp., 20-1 Shintomi, Futtsu, Chiba 293-8511 (Japan); Niwa, Y; Nomura, M [Photon Factory, IMSS, KEK, 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan); Inada, Y, E-mail: kimura.masao@nsc.co.j [Present: College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)

    2009-11-15

    We investigated the change in structures during reduction and oxidation of a new type of Pd on Sr-Fe-O catalyst for exhaust emission. In situ DXAFS techniques have shown changes in palladium states and oxygen concentration simultaneously during reduction and oxidation reactions. Quantitative analysis has shown that palladium atoms change their states between Pd(II{sup *}) and Pd(0) reversibly according to the gas atmosphere accompanying changes in the oxygen concentration. This reaction explains the high performance of the catalyst.

  9. Observation and analysis of incomplete fusion reactions induced by (12C, 14N, 16O, 22Ne) ions

    International Nuclear Information System (INIS)

    The mechanism of the reactions induced by heavy ions has been studied. The experiments were concerned with incident channels which lead to the formation of intermediate nuclei with atomic mass (6412C, 14N, 16O, 22Ne) as projectiles respectively. The detection of light fragments (2< Z<12) is studied. A three solid-state-detector telescope, with associated electronics is used which allows the separation of reaction products according to their charge. The main features of deep inelastic collisions are discussed: large kinetic energy loss, and important nucleon transfer as a function of the angular detection. The time evolution of the reaction has been studied, then the results are compared with a scattering model suggested by Noremberg. A theoretical calculation based on both classical and statistical approaches giving the total cross-sections for any exit channel has been proposed

  10. First observation of new heavy multi-nucleon transfer products in the 48Ca+248Cm reaction performed at SHIP

    International Nuclear Information System (INIS)

    Heavy ion fusion reactions have been successfully used to synthesise super heavy elements (SHE). The heaviest element produced up to now is element Z=118 and the production cross-section limit using conventional HI-fusion has been reached experimentally. Since these methods cannot be applied to reach neutron-rich super heavy nuclei due to the lack of sufficiently neutron-rich projectile and target nuclei. New calculations suggest the use of Multi Nucleon Transfer (MNT) reactions as a promising pathway to the synthesis of new neutron-rich SHE with proton numbers up to about Z=106. In this work, we present results from the analysis of experimental data on MNT reactions with the 48Ca projectile incident on 248Cm target. The experiment was performed at SHIP, GSI in 2010

  11. Low dose endotoxin priming is accountable for coagulation abnormalities and organ damage observed in the Shwartzman reaction. A comparison between a single-dose endotoxemia model and a double-hit endotoxin-induced Shwartzman reaction

    Directory of Open Access Journals (Sweden)

    Cate Hugo

    2006-08-01

    Full Text Available Abstract The clinical response of sepsis to a systemic inflammatory infection may be complicated by disseminated intravascular coagulation or DIC. In order to experimentally study the syndrome of DIC, we aimed for a severe sepsis model complicated by disseminated coagulation. Most -simplified- experimental models describing coagulation abnormalities as a consequence of sepsis are based on single dose endotoxemia. The so called-Shwartzman reaction contrarily, is elicited by a low dose endotoxin priming followed by an LPS challenge and is characterized by pathological manifestations that represent the syndrome of DIC. In order to investigate whether the Shwartzman reaction is superior to a single endotoxin challenge as a model for sepsis-induced DIC and to determine what the pathological effect is of an encounter of low endotoxin prior to an LPS challenge, we undertook the present study. In this study we demonstrate that low-dose endotoxin priming prior to an LPS challenge in the Shwartzman reaction is accountable for micro-vascular thrombosis in lung and liver and subsequent (multi- organ failure, not observed after a single-dose endotoxin challenge, which indicates that the Shwartzman reaction is well suited-model to study sepsis-induced DIC adversities. Remarkably, only minor differences in the innate immune response were established between the single-dose endotoxin challenge and the Shwartzman reaction.

  12. Observation of hydroxymethyl hydroperoxide in a reaction system containing CH{sub 2}OO and water vapor through pure rotational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Masakazu; Endo, Yasuki, E-mail: endo@bunshi.c.u-tokyo.ac.jp [Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2015-10-28

    Pure rotational transitions of hydroxymethyl hydroperoxide (HMHP) were observed in the discharged plasma of a CH{sub 2}I{sub 2}/O{sub 2}/water gas mixture, where the water complex with the simplest Criegee intermediate CH{sub 2}OO has been identified [M. Nakajima and Y. Endo, J. Chem. Phys. 140, 134302 (2014)]. Isotope experiments using heavy water support that the currently observed HMHP molecule was produced by the reaction of CH{sub 2}OO with water vapor. The observed species was identified as the most stable conformer with the help of quantum chemical calculations. We also clarified that productions of formic acid and dioxirane are promoted by the existence of water vapor in the discharged reaction system.

  13. Measurement of the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction cross section, of relevance to $\\gamma$-ray observation of core collapse supernovae, using reclaimed $^{44}$Ti

    CERN Multimedia

    Despite decades of research, fundamental uncertainties remain in the underlying explosion mechanism of core collapse supernovae. One of the most direct methods that might help resolve this problem is a comparison of the predicted to the observed flux of $\\gamma$-rays due to decay of $^{44}$Ti produced in the explosion, as it is believed this could reveal the location of the mass cut, a key hydrodynamical property of the explosion. Such a study is at present limited by the uncertainty in the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction rate. In this experiment we propose to measure the cross section for this reaction at astrophysically relevant energies. The single previous measurement of this reaction was limited to higher energies due to low beam intensities. Here, a more intense beam will be employed, generated from $^{44}$Ti reclaimed as part of the ERAWAST project at PSI.

  14. Rabies Vaccine Adverse Reactions Observed after Inoculation%狂犬病疫苗接种后不良反应观察

    Institute of Scientific and Technical Information of China (English)

    张艳芳

    2014-01-01

    Objective To analyze rabies vaccine after the occurrence of adverse reactions, and then take corresponding measures, to enhance immunity. Methods After exposure to rabies doctor object, 117 people, al the rabies vaccine, then observe adverse reactions. Results Al the vaccinated did not appear abnormal response, general reaction rate at 12.82%, among them the occurring rate of local reactions at 12.82%, the whole body reaction rate at 14.53%, vaccination reaction factors such as age, gender dif erences, but tend to occur in vaccinated 1 and 2. Conclusion Shal be as soon as possible fol owing exposure to rabies vaccine of inject wild dog, at the same time take measures to prevent the occurrence of adverse reactions.%目的分析狂犬病疫苗接种后不良反应的发生情况,进而采取相应措施,力求提高免疫率。方法选择狂犬病暴露后的就诊对象117例,全部接种狂犬疫苗,然后观察不良反应。结果所有接种者都未出现异常反应,一般反应发生率在12.82%,其中局部反应发生率在12.82%,全身反应发生率在14.53%,接种反应无年龄、性别等因素的差异,但多发生在接种第1和第2针。结论狂犬病暴露后均应尽快注射狂犬疫苗,同时采取措施预防不良反应的发生。

  15. Observation of Organometallic and Radical Intermediates Formed during the Reaction of Methyl-Coenzyme M Reductase with Bromoethanesulfonate†

    OpenAIRE

    Li, Xianghui; Telser, Joshua; Hoffman, Brian M.; Gerfen, Gary; Ragsdale, Stephen W.

    2010-01-01

    Methyl-coenzyme M reductase (MCR) from methanogenic archaea catalyzes the final step of methane formation, in which methyl-coenzyme M (2-methylthioethane sulfonate, methyl-SCoM) is reduced with coenzyme B (N-7-mercaptoheptanolyl-threonine phosphate, CoBSH) to form methane and the heterodisulfide CoBS-SCoM. The active dimeric form of MCR contains two Ni(I)-F430 prosthetic groups, one in each monomer. This manuscript describes studies of the reaction of the active Ni(I) state of MCR (MCRred1) w...

  16. In situ observation of the reaction of tantalum with nitrogen in a laser heated diamond anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Alexandra, E-mail: friedrich@kristall.uni-frankfurt.d [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Winkler, Bjoern; Bayarjargal, Lkhamsuren [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Juarez Arellano, Erick A. [Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Morgenroth, Wolfgang; Biehler, Jasmin; Schroeder, Florian [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Yan, Jinyuan; Clark, Simon M. [Advanced Light Source, Lawrence Berkeley National Laboratory, MS6R2100, 1 Cyclotron Road, Berkeley, CA 94720-8226 (United States)

    2010-07-16

    Tantalum nitrides were formed by reaction of the elements at pressures between 9(1) and 12.7(5) GPa and temperatures >1600-2000 K in the laser-heated diamond anvil cell. The incorporation of small amount of nitrogen in the tantalum structure was identified as the first reaction product on weak laser irradiation. Subsequent laser heating led to the formation of hexagonal {beta}-Ta{sub 2}N and orthorhombic {eta}-Ta{sub 2}N{sub 3}, which was the stable phase at pressures up to 27 GPa and high temperatures. No evidence was found for the presence of {epsilon}-TaN, {theta}-TaN, {delta}-TaN, Ta{sub 3}N{sub 5}-I or Ta{sub 3}N{sub 5}-II, which was predicted to be the stable phase at P>17 GPa and T=2800 K, at the P,T-conditions of this experiment. The bulk modulus of {eta}-Ta{sub 2}N{sub 3} was determined to be B{sub 0}=319(6) GPa from a 2nd order Birch-Murnaghan equation of state fit to the experimental data, while quantum mechanical calculations using the density functional theory gave a bulk modulus of B{sub 0}=348.0(9) GPa for a 2nd-order fit or B{sub 0}=339(1) GPa and B{sup '}=4.67(9) for a 3rd-order fit. The values show the large incompressibility of this high-pressure phase. From the DFT data the structural compression mechanism could be determined.

  17. Canine atopic dermatitis in Greece: clinical observations and the prevalence of positive intradermal test reactions in 91 spontaneous cases.

    Science.gov (United States)

    Saridomichelakis, M N; Koutinas, A F; Gioulekas, D; Leontidis, L

    1999-07-01

    Atopic dermatitis was diagnosed in a total of 91 dogs by combining the compatible historical evidence and clinical signs with the presence of one or more positive intradermal test reactions well correlated with the exposure to the aeroallergens and the seasonality of the clinical signs. Compared to the general hospital population Yorkshire terriers, Chinese Shar-Peis and cocker spaniels showed a strong predilection. No such predilection was found regarding the sex of the animals. The age of the dogs at the onset of the clinical signs ranged from 2 months to 8 years (median: 2.5 years). Moderate to severe pruritus, noticed in all the 91 dogs, was either localized (29/91) or generalized (64/91) and non-seasonal (43/91), seasonal (19/91) or of unknown seasonality (29/91). The most common cutaneous lesions included erythema, hyperpigmentation, hypotrichosis and crusts; their body distribution was generalized (64%) or localized (36%) with the feet as the most common site of involvement. Five dogs that had unlesional skin were significantly younger and had been pruritic for a shorter period of time compared to the majority of our study population. Otitis externa (43/91) and bacterial pyoderma (30/91) were the most common conditions associated with atopic dermatitis, while the prevalence of Malassezia dermatitis was very low (2/91). Of the other allergic skin diseases flea allergic dermatitis was the most common (29/91) followed by food hypersensitivity (2 out of the 15 dogs tested). The majority of the dogs demonstrated multiple sensitivities to the 50 aeroallergens tested, while domestic mites (77/91), and particularly Dermatophagoides farinae (64/91), were the most commonly implicated. The total number of the positive intradermal test reactions was increasing parallel to the age of the dogs but it was negatively associated with the presence of skin lesions on the carpal and tarsal joints. PMID:10490235

  18. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions

    International Nuclear Information System (INIS)

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  19. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions

    Science.gov (United States)

    Shen, Cenchao; Yang, Wenjuan; Ji, Qiaoli; Maki, Hisaji; Dong, Anjie; Zhang, Zhizhou

    2009-11-01

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  20. Observation of the Exclusive Reaction e+e- -> phi eta at sqrt{s}=10.58 GeV

    CERN Document Server

    Aubert, B; Boutigny, D; Karyotakis, Yu; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes-Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Tackmann, K; Wenzel, W A; Del Amo-Sánchez, P; Barrett, M; Harrison, T J; Hart, A J; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schröder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Asgeirsson, D J; Çuhadar-Dönszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M A; Martin, E C; Röthel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Zhang, L; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Williams, D C; Wilson, M G; Winstrom, L O; Albert, J; Chen, E; Cheng, C H; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Thiebaux, C; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Nikolich, M B; Panduro-Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F R; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flächer, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Salvatore, F; Wren, A C; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, Gallieno; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; LoSecco, J M; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Ter-Antonian, R; Wong, Q K; Blount, N L; Brau, J E; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Potter, C T; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; Hartfiel, B L; Leruste, P; Malcles, J; Ocariz, J

    2006-01-01

    We report the observation of $\\e^+e^-\\to \\phi\\eta$ near $\\sqrt{s}$ = 10.58 GeV with 6.5 $\\sigma$ significance in the $K^+K^-\\gamma\\gamma$ final state in a data sample of 224 $fb^{-1}$ collected by the BaBar experiment at the PEP-II $e^+e^-$ storage rings. We measure the restricted radiation-corrected cross section to be $\\sigma(\\e^+e^- \\to \\phi \\eta) =

  1. In situ observation of eutectoid reaction forming a PbTe-Sb₂Te₃ thermoelectric nanocomposite by synchrotron X-ray diffraction

    OpenAIRE

    Ikeda, Teruyuki; Toberer, Eric S; Ravi, Vilupanur A.; Snyder, G. Jeffrey; Aoyagi, Shinobu; Nishibori, Eiji; Sakata, Makoto

    2009-01-01

    In situ high-temperature powder X-ray diffraction experiments have been performed on performed on Pb10.5Sb6Te57.9 using using a synchrotron X-ray source to observe the eutectoid reaction from Pb2Sb6Te11 to PbTe and Sb2Te3. Molar fractions of the constituent phases and fraction transformed were obtained as functions of time. The experimental fraction transformed vs. time curve were well fitted by the Kolmogorov–Johnson–Mehl–Avrami equation with an Avrami index n = 1.4. The small n value sugges...

  2. Measurement of beam-recoil observables O{sub x}, O{sub z} and target asymmetry T for the reaction {gamma}p{yields}K{sup +}{lambda}

    Energy Technology Data Exchange (ETDEWEB)

    Lleres, A.; Bocquet, J.P.; Calvat, P.; Perrin, C.; Rebreyend, D.; Renard, F.; Russew, T. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, Grenoble (France); Bartalini, O.; Capogni, M.; D' Angelo, A.; Fantini, A.; Franco, D.; Schaerf, C.; Vegna, V. [Universita di Roma ' Tor Vergata' , Dipt. di Fisica, Roma (Italy); INFN - Sezione di Roma Tor Vergata, Roma (Italy); Bellini, V.; Randieri, C. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipt. di Fisica ed Astronomia, Catania (Italy); Casano, L.; Di Salvo, R.; Moricciani, D. [INFN - Sezione di Roma Tor Vergata, Roma (Italy); Castoldi, M. [INFN - Sezione di Genova, Genova (Italy); Didelez, J.P.; Guidal, M.; Hourany, E.; Kunne, R. [Universite Paris-Sud 11, CNRS/IN2P3, IPNO, Orsay (France); Gaulard, C.; Levi Sandri, P. [INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Gervino, G. [Universita di Torino, Dipt. di Fisica Sperimentale, Torino (Italy); INFN - Sezione di Torino, Torino (Italy); Ghio, F.; Girolami, B. [INFN - Sezione di Roma, Roma (Italy); Istituto Superiore di Sanita, Roma (Italy); Giusa, A.; Mammoliti, F.; Russo, G.; Sperduto, M.L. [INFN - Sezione di Catania, Catania (Italy); Universita di Catania, Dipt. di Fisica ed Astronomia, Catania (Italy); Kuznetsov, V. [Institute for Nuclear Research, Moscow (Russian Federation); Kyungpook National University, Daegu (Korea); Lapik, A.; Mushkarenkov, A.N.; Nedorezov, V.; Rudnev, N.; Turinge, A. [Institute for Nuclear Research, Moscow (Russian Federation); Mandaglio, G. [INFN - Sezione di Catania, Catania (Italy); Universita di Messina, Dipt. di Fisica, Messina (Italy); Nicoletti, L. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Inst. National Polytechnique de Grenoble, Grenoble (France); Univ. di Roma ' Tor Vergata' , Dipt. di Fisica, Roma (Italy); INFN - Sezione di Roma Tor Vergata, Roma (Italy); Sutera, M.C. [INFN - Sezione di Catania, Catania (Italy)

    2009-02-15

    The double polarization (beam-recoil) observables O{sub x} and O{sub z} have been measured for the reaction {gamma}p{yields}K{sup +}{lambda} from threshold production to E{sub {gamma}}{proportional_to}1500 MeV. The data were obtained with the linearly polarized beam of the GRAAL facility. Values for the target asymmetry T could also be extracted despite the use of an unpolarized target. Analyses of our results by two isobar models tend to confirm the necessity to include new or poorly known resonances in the 1900 MeV mass region. (orig.)

  3. Experimental measurements of the O15(alpha,gamma)Ne19 reaction rate vs. observations of type I X-ray bursts

    CERN Document Server

    Fisker, J L; Görres, J; Wiescher, M; Cooper, R L; Fisker, Jacob Lund; Tan, Wanpeng; Goerres, Joachim; Wiescher, Michael; Cooper, Randall L.

    2007-01-01

    Neutron stars in close binary star systems often accrete matter from their companion stars. Thermonuclear ignition of the accreted material in the atmosphere of the neutron star leads to a thermonuclear explosion which is observed as an X-ray burst occurring periodically between hours and days depending on the accretion rate. The ignition conditions are characterized by a sensitive interplay between the continuously accreting fuel supply and depletion by nuclear burning via the hot CNO cycles. Therefore the ignition depends critically on the hot CNO breakout reaction O15(alpha,gamma)Ne19 that regulates the flow between the beta-limited hot CNO cycle and the rapid proton capture process. Until recently, the O15(alpha,gamma)Ne19 reaction rate was not known experimentally and the theoretical estimates carried significant uncertainties. In this paper we report on the astrophysical consequences of the first measurement of this reaction rate on the thermonuclear instability that leads to type I X-ray bursts on accr...

  4. Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate.

    Science.gov (United States)

    Portu, Agustina; Rossini, Andrés Eugenio; Thorp, Silvia Inés; Curotto, Paula; Pozzi, Emiliano César Cayetano; Granell, Pablo; Golmar, Federico; Cabrini, Rómulo Luis; Martin, Gisela Saint

    2015-08-01

    The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an "imprint" of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013 cm-2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines and in vitro evaluation of the effect of diverse boron compounds are feasible with this methodology. PMID:26155721

  5. First Measurement of the Polarization Observable E in the $\\vec p(\\vec \\gamma,\\pi^+)n$ Reaction up to 2.25 GeV

    CERN Document Server

    Strauch, S; Döring, M; Klempt, E; Nikonov, V A; Pasyuk, E; Rönchen, D; Sarantsev, A V; Strakovsky, I; Workman, R; Adhikari, K P; Adikaram, D; Anderson, M D; Pereira, S Anefalos; Anisovich, A V; Badui, R A; Ball, J; Batourine, V; Battaglieri, M; Bedlinskiy, I; Benmouna, N; Biselli, A S; Brock, J; Brooks, W K; Burkert, V D; Cao, T; Carlin, C; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Compton, N; Contalbrigo, M; Cortes, O; Crede, V; Dashyan, N; D'Angelo, A; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dugger, M; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Forest, T A; Fradi, A; Gevorgyan, N; Ghandilyan, Y; Giovanetti, K L; Girod, F X; Glazier, D I; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hattawy, M; Hicks, K; Ho, D; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Keith, C D; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Kubarovsky, V; Kuhn, S E; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; McKinnon, B; Meekins, D G; Meyer, C A; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Munevar, E; Camacho, C Munoz; Nadel-Turonski, P; Net, L A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Park, K; Peng, P; Phelps, W; Phillips, J J; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Raue, B A; Ripani, M; Ritchie, B G; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Seely, M L; Senderovich, I; Sharabian, Y G; Simonyan, A; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Stoler, P; Stepanyan, S; Sytnik, V; Taiuti, M; Tian, Ye; Trivedi, A; Tucker, R; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2015-01-01

    First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\\vec \\gamma \\vec p \\to \\pi^+n$, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, J\\"ulich, and SAID groups.

  6. Novel observations of dynamic crystallography in the solid-state LiBH4/MgH2 hydrogen absorption reaction

    International Nuclear Information System (INIS)

    The Lithium hydride/magnesium di-boride system has been the subject of much investigation due to its potential in solving the mobile hydrogen storage problem. While its weight (11.4 wt%) and volume densities of hydrogen are favourable, it has been found to react at unfavourable temperatures. Performance improvements have been made since through the use of additives and micro-/nano-structuring. In order to make neutron diffraction viable, magnesium di-boride was synthesised using 11 B enriched boron. This was then used as a constituent in the samples, which consisted primarily of a 2:1 molar ratio LiH to MgB2, some an additives 5 at% (VCI3). In-situ time-of-flight neutron diffraction was undertaken (Polaris, ISIS, United Kingdom) for both the forward and back reaction: 2LiH + MgB2 + 4H2 ↔ 2LiBH4 + MgH2. The absorption was performed at the temperature of 250°C so as to have the products of the reaction remain solid, and thus measurable using diffraction. The reaction was observed to progress, although not to completion due to time restrictions. A crystallographic change was observed in the formed lithium borohydride; a lattice parameter shifting as a function of hydrogen content within the sample. Attenuation correction was performed, applying the model that Gray et al proposed for masked TOF cells. For the actual application this model, assumptions and approximations were necessary in this instance.

  7. Multiphoton ionization spectra of radical products in the F(2P)+ketene system: Spectral assignments and formation reaction for CH2F, observation of CF and CH

    Science.gov (United States)

    Hudgens, Jeffrey W.; Dulcey, C. S.; Long, George R.; Bogan, Denis J.

    1987-10-01

    The reactions of F(2P)+ketene and F(2P)+ketene-d2 were studied in a flow reactor. Spectra of the radical products CH2F, CD2F, CH, CF, and atomic carbon were detected between 292-395 nm by resonance enhanced multiphoton ionization (REMPI) mass spectrometry. Fluoromethyl radicals were identified as a major product of the F+ketene elementary reaction. REMPI spectra of fluoromethyl radicals originated from two-photon preparation of 3p, 4p, and 5p Rydberg states (quantum defect ˜0.6). Absorption of a third laser photon ionized the radicals, a 2+1 REMPI mechanism. Rydberg band origins were observed in CH2F at ν00=52 863, 63 275, and 67 265 cm-1 and in CD2F at ν00=52 786, 63 195, and 67 186 cm-1. A normal mode analysis revealed the vibrational frequencies of the C-F stretch, CH2 scissors, and out-of-plane bending modes in the Rydberg states. The ground state out-of-plane bending frequency in CH2F is 260(30) cm-1 and in CD2F it is 170(30) cm-1. CH radicals were generated by the photolysis of ketene and observed at ˜311 nm by two-photon excitation through the D 2Π(v'=2) ←←X 2Πr band. The reaction mechanism that generated the CF radicals was not determined. The REMPI CF radical spectrum generated by a 2+1 photon mechanism appeared as a series of bandheads described by the constants ν00=˜52 572 cm-1, ωe =1820 cm-1, and ωexe =-18.2 cm-1.

  8. In situ SEM observation of the Si negative electrode reaction in an ionic-liquid-based lithium-ion secondary battery.

    Science.gov (United States)

    Tsuda, Tetsuya; Kanetsuku, Tsukasa; Sano, Teruki; Oshima, Yoshifumi; Ui, Koichi; Yamagata, Masaki; Ishikawa, Masashi; Kuwabata, Susumu

    2015-06-01

    By exploiting characteristics such as negligible vapour pressure and ion-conductive nature of an ionic liquid (IL), we established an in situ scanning electron microscope (SEM) method to observe the electrode reaction in the IL-based Li-ion secondary battery (LIB). When 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide ([C2mim][FSA]) with lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]) was used as the electrolyte, the Si negative electrode exhibited a clear morphology change during the charge process, without any solid electrolyte interphase (SEI) layer formation, while in the discharge process, the appearance was slightly changed, suggesting that a morphology change is irreversible in the charge-discharge process. On the other hand, the use of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mim][TFSA]) with Li[TFSA] did not induce a change in the Si negative electrode. It is interesting to note this distinct contrast, which could be attributed to SEI layer formation from the electrochemical breakdown of [C2mim](+) at the Si negative electrode|separator interface in the [C2mim][TFSA]-based LIB. This in situ SEM observation technique could reveal the effect of the IL species electron-microscopically on the Si negative electrode reaction.

  9. Observation of high-j quasiparticle states in Cm249 by in-beam γ-ray spectroscopy using heavy-ion transfer reactions

    Science.gov (United States)

    Ishii, T.; Makii, H.; Asai, M.; Tsukada, K.; Toyoshima, A.; Matsuda, M.; Makishima, A.; Shigematsu, S.; Kaneko, J.; Shizuma, T.; Toume, H.; Hossain, I.; Kohno, T.; Ogawa, M.

    2008-11-01

    We have measured de-excitation γ rays in Cm249 populated by one-neutron stripping reactions with a Cm248 target and 162-MeV O16, 162-MeV O18, and 120-MeV C13 beams. γ rays in Cm249 were identified by measuring kinetic energies of outgoing particles using Si ΔE-E detectors. It was demonstrated that high-j orbitals were selectively populated in the (O16, O15) reaction having a large negative Q value. We have observed eight quasiparticle states above the deformed shell gap of N=152. The 1/2+[620], 1/2-[750], and 7/2+[613] bands were extended up to 19/2+, 19/2-, and 13/2+ states, respectively. We have established the 9/29/2+[615] state at 526 keV, the 9/29/2+[604] state with a short life of T1/2≪2 ps at 1030 keV, and the 11/211/2-[725] state with T1/2=19(1) ns at 375 keV. Furthermore, the 17/21/2+[880] state, having a large component of the k17/2 spherical single-particle state, has been identified at 1505 keV. We discuss the properties of those quasiparticle states in the framework of a deformed shell model.

  10. Observation of high-j quasiparticle states in 249Cm by in-beam γ-ray spectroscopy using heavy-ion transfer reactions

    International Nuclear Information System (INIS)

    We have measured de-excitation γ rays in 249Cm populated by one-neutron stripping reactions with a 248Cm target and 162-MeV 16O, 162-MeV 18O, and 120-MeV 13C beams. γ rays in 249Cm were identified by measuring kinetic energies of outgoing particles using Si ΔE-E detectors. It was demonstrated that high-j orbitals were selectively populated in the (16O, 15O) reaction having a large negative Q value. We have observed eight quasiparticle states above the deformed shell gap of N=152. The 1/2+[620], 1/2-[750], and 7/2+[613] bands were extended up to 19/2+, 19/2-, and 13/2+ states, respectively. We have established the 9/2 9/2+[615] state at 526 keV, the 9/2 9/2+[604] state with a short life of T1/2-[725] state with T1/2=19(1) ns at 375 keV. Furthermore, the 17/2 1/2+[880] state, having a large component of the k17/2 spherical single-particle state, has been identified at 1505 keV. We discuss the properties of those quasiparticle states in the framework of a deformed shell model

  11. Observation of a New JPC = 1-+ Exotic State in the Reaction π-p → π+ π-π- p at 18 GeV/c

    International Nuclear Information System (INIS)

    A partial-wave analysis of the reaction π-p→π+π- π-p at 18 GeV/c has been performed on a data sample of 250000 events obtained by Brookhaven experiment E852. The expected JPC=1++a1(1260) , 2++a2(1320) , and 2-+π2(1670) resonant states are clearly observed. The exotic JPC=1-+ wave produced in the natural parity exchange processes shows distinct resonancelike phase motion at about 1.6 GeV/c2 in the ρπ channel. A mass-dependent fit results in a resonance mass of 1593±8+29-47 MeV /c2 and a width of 168±20+150-12 MeV /c2 . copyright 1998 The American Physical Society

  12. Intense secondary aerosol formation due to strong atmospheric photochemical reactions in summer: observations at a rural site in eastern Yangtze River Delta of China.

    Science.gov (United States)

    Wang, Dongfang; Zhou, Bin; Fu, Qingyan; Zhao, Qianbiao; Zhang, Qi; Chen, Jianmin; Yang, Xin; Duan, Yusen; Li, Juan

    2016-11-15

    High pollution episodes of PM2.5 and O3 were frequently observed at a rural site (N31.0935º, E120.978°) in eastern Yangtze River Delta (YRD) in summer. To study the impacts of photochemical reactions on secondary aerosol formation in this region, we performed real-time measurements of the mass concentration and composition of PM2.5, particle size distribution (13.6~736.5 nm), concentrations of gas pollutants including O3, SO2, NO2, CO, non-methane hydrocarbons (NMHC)), and nitrate radical in 2013. During the sampling period, the average concentration of PM2.5 was 76.1 (± 16.5) μg/m(3), in which secondary aerosol species including sulfate, nitrate, ammonium, and secondary organic aerosol (SOA) accounted for ~ 62%. Gas-phase oxidation of SO2 was mainly responsible for a fast increase of sulfate (at 1.70 μg/m(3)/h) in the morning. Photochemical production of nitric acid was intense during daytime, but particulate nitrate concentration was low in the afternoon due to high temperature. At night, nitrate was mainly formed through the hydrolysis of NO3 and/or N2O5. The correlations among NMHC, Ox (= O3 + NO2), and SOA suggested that a combination of high emission of hydrocarbons and active photochemical reactions led to the rapid formation of SOA. In addition, several new particle formation and fast growth events were observed despite high ambient aerosol loading. Since the onset of new particle events was accompanied by a rapid increase of H2SO4 and SOA, enhanced formation of sulfate and SOA driven by photochemical oxidation likely promoted the formation and growth of new particles. Together, our results demonstrated that strong atmospheric photochemical reactions enhanced secondary aerosols formation and led to the synchronous occurrence of high concentrations of PM2.5 and O3 in a regional scale. These findings are important for better understanding the air pollution in summer in YRD. PMID:27418517

  13. On the structure observed in the in-flight ${}^{3}\\text{He} ( K^{-} , \\, \\Lambda p ) n$ reaction at J-PARC

    CERN Document Server

    Sekihara, Takayasu; Ramos, Angels

    2016-01-01

    A theoretical investigation is done to clarify the origin of the peak structure observed near the $K^{-} p p$ threshold in the in-flight ${}^{3}\\text{He} ( K^{-}, \\, \\Lambda p ) n$ reaction of the J-PARC E15 experiment, which could be a signal of the lightest kaonic nuclei, that is, the $\\bar{K} N N (I=1/2)$ state. For the investigation, we evaluate the $\\Lambda p$ invariant mass spectrum assuming two possible scenarios to interpret the experimental peak. One assumes that the $\\Lambda (1405)$ resonance is generated after the emission of an energetic neutron from the absorption of the initial $K^-$, not forming a bound state with the remaining proton. This uncorrelated $\\Lambda (1405) p$ system subsequently decays into the final $\\Lambda p$. The other scenario implies that, after the emission of the energetic neutron, a $\\bar{K} N N$ bound state is formed, decaying eventually into a $\\Lambda p$ pair. Our results show that the experimental signal observed in the in-flight ${}^{3}\\text{He} ( K^{-} , \\, \\Lambda p...

  14. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  15. Investigation of the high energy statistical γ-ray spectrum observed in the 16O + 144Nd reaction and of its influence on the resulting 160Er deexcitation

    International Nuclear Information System (INIS)

    We have studied the high energy statistical γ-ray spectrum observed in the fusion-evaporation reaction 16O + 144Nd → 160Er* and the influence of the γ-strength function on the production cross section of the evaporation residues. It was possible to reproduce the measured statistical γ-ray spectra in the framework of the statistical model by assuming that at all excitation energies, the dipole strength function has a lorentzian shape characteristic of the electric dipole giant resonance. However, our analysis demonstrates that there is a very strong correlation between the parameters of this strength function and the level density parameter. The comparison of the statistical γ-ray spectra obtained at three different excitation energies shows that the high energy part of the spectra comes mainly from the first steps of the decay cascade in direct competition with particle evaporation. This is in agreement with the prediction of the statistical model. By measuring both the statistical γ-ray spectrum and the evaporation residues cross section for the same reaction, it was possible to show that using an energy dependent γ-strength function which describes the measured γ ray spectrum improves the description of the evaporation residues cross section by the statistical model as compared to the results of more standard calculations where an energy independent dipole strength function is used. This work shows that the study of the γ-strength function at high energy could be a powerful probe of the nuclei far from the yrast line but that to realize this, it will be necessary to improve our knowledge of the level density proprieties at high excitation energy. (author)

  16. PROSPECTIVE OBSERVATIONAL, NON-RANDOMIZED, PARALLEL SEQUENCE STUDY FOR ASSESSMENT OF ADVERSE DRUG REACTIONS DUE TO CHEMOTHERAPEUTIC TREATMENT IN DIFFERENT TYPES OF CANCER PATIENTS

    Directory of Open Access Journals (Sweden)

    Mrugank B.P. * and Hareesha R.P.

    2013-01-01

    Full Text Available Objective: To assess incidence, causality, severity, predictability and preventability of adverse drug reactions (ADRs in hospitalised oncology patients.Materials and Methods: A prospective observational, non-randomized, parallel sequence study was conducted at Dr B. Borooah Cancer Institute (BBCI after getting an approval from human ethical committee. Patients hospitalised at BBCI from Aug 2010 to June 2011 were interviewed about symptoms related to their drug therapy. Patient medical records were also reviewed for data collection.Results: Total 663 patients associated with hospitalizations were interviewed. 899 ADRs were identified in total 410 (61.84% patients detected with ADRs. Most of all ADRs were moderate, predictable and not preventable. The most common ADRs were leucopenia, weakness, anorexia, alopecia, vomiting, diarrhoea, nausea, abdominal pain, fatigue, and anaemia in this study.Conclusions: For definite conclusion study should be repeated. Strict drug analyzing and in vivo study is also required if feasible.Key message: The process of defining and concluding about ADRs should be continuous and ongoing to keep a record of newly marketed drugs and medicinal products.

  17. A new study of the $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction deep underground: Feasibility, setup, and first observation of the 186 keV resonance

    CERN Document Server

    Cavanna, F; Menzel, M -L; Aliotta, M; Anders, M; Bemmerer, D; Broggini, C; Bruno, C G; Caciolli, A; Corvisiero, P; Davinson, T; di Leva, A; Elekes, Z; Ferraro, F; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D A; Somorjai, E; Straniero, O; Strieder, F; Szücs, T; Trezzi, D

    2014-01-01

    The $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle is active in asymptotic giant branch stars as well as in novae and contributes to the nucleosythesis of neon and sodium isotopes. In order to reduce the uncertainties in the predicted nucleosynthesis yields, new experimental efforts to measure the $^{22}$Ne(p,$\\gamma$)$^{23}$Na cross section directly at the astrophysically relevant energies are needed. In the present work, a feasibility study for a $^{22}$Ne(p,$\\gamma$)$^{23}$Na experiment at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400\\,kV accelerator deep underground in the Gran Sasso laboratory, Italy, is reported. The ion beam induced $\\gamma$-ray background has been studied. The feasibility study led to the first observation of the $E_{\\rm p}$ = 186\\,keV resonance in a direct experiment. An experimental lower limit of 0.12\\,$\\times$\\,10$^{-6}$\\,eV has been obtained for the resonance strength. Informed by the feasibility study,...

  18. Variation of adverse drug reaction profile of platinum-based chemotherapy with body mass index in patients with solid tumors: An observational study

    Directory of Open Access Journals (Sweden)

    Dattatreyo Chatterjee

    2014-01-01

    Full Text Available Objectives: Toxicity of cancer chemotherapy may be affected by nutritional status of patients which is reflected in the body mass index (BMI. We sought to assess whether the adverse drug reaction (ADR profile of platinum-based chemotherapy varies with BMI status. Materials and Methods: Adult patients of either sex, suffering from a solid tumor (lung, head and neck, ovary, gall bladder, stomach, colon and started on platinum-based chemotherapy as initial treatment were included. BMI at chemotherapy commencement was obtained from medical records. Events were recorded and graded as per Eastern Co-operative Oncology Group Common Toxicity Criteria-patients′ complaints; clinically evident signs and laboratory reports were considered. Frequencies of individual adverse events were compared between low BMI (<18.5 kg/m 2 and satisfactory BMI groups. Similar comparisons were done for events with grades 2 or 3 severities. Results: A total of 50 patients were observed over a 3-month period of whom 17 (34% belonged to the low BMI group. Nausea, vomiting, diarrhea, stomatitis, anemia, alopecia, tinnitus and paresthesia were the commonly observed ADRs. The frequencies of anemia (P = 0.152 and vomiting (P = 0.140 and severity of grades of nausea (P = 0.066, anemia (P = 0.120 and paresthesia (P = 0.128 showed a higher trend in the low BMI group though differences were not statistically significant. The frequencies of tinnitus (P = 0.021 and paresthesia overall (P = 0.036 were significantly higher in the low BMI group. Conclusion: ADR profile of primary platinum-based chemotherapy appears to be partly influenced by BMI. This suggests the importance of maintaining adequate nutrition in patients and the need for greater vigilance in those with low BMI.

  19. New observation on a class of old reactions:Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Solvent-free reactions of aromatic aldehydes with three representative ketones,including acetophenone,acetone and cyclohexanone,have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K2CO3.It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst.Under the optimized experimental conditions,1,2,3,4,5-pentasubstituted cyclohexanols,α,β-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields.Two Kostanecki’s triketones were separated,The composition and structure were affirmed by X-ray crystallographic analysis.

  20. Direct observation of rate determining step for Nd2NiO4+δ SOFC cathode reaction by operando electrochemical XAS

    International Nuclear Information System (INIS)

    The oxygen chemical potential of dense Nd2NiO4+δ thin films on Zr0.92Y0.08O1.96 electrolyte was investigated by operando X-ray absorption spectroscopy (XAS) measurements. Operando XAS at the Ni K-edge was measured under an applied voltage and various oxygen partial pressures at high temperature to simulate the operating conditions of solid oxide fuel cells (SOFCs). The absorption edge energy under various polarizations is similar to those measured under equivalent oxygen partial pressures under open circuit condition. Thus, the oxygen chemical potential changes drastically at the electrode/gas interface and the rate-determining step of this model system is the surface reaction. This study provides direct evidence for the rate-determining step of the SOFC cathode reaction. (author)

  1. Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

    OpenAIRE

    Kaya, Sarp; Malacrida, Paolo; Casalongue, Hernan G. Sanchez; Masini, Federico; Hernandez-Fernandez, Patricia; Deiana, Davide; Ogasawara, Hirohito; Stephens, Ifan E. L.; Nilsson, Anders; Chorkendorff, Ib

    2015-01-01

    Size-selected 9 nm PtxY nanoparticles have recently shown an outstanding catalytic activity for the oxygen reduction reaction, representing a promising cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Studying their electrochemical dealloying is a fundamental step towards the understanding of both their activity and stability. Herein, size-selected 9 nm PtxY nanoparticles have been deposited on the cathode side of a PEMFC specifically designed for in situ ambient pressure X-...

  2. Multi-state stochastic hotchpotch model gives rise to the observed mesoscopic behaviour in the non-stirred Belousov--Zhabotinsky reaction

    CERN Document Server

    Štys, Dalibor; Zhyrova, Anna; Rychtáriková, Renata; Štys, Kryštof M; Náhlík, Tomáš

    2016-01-01

    Mesoscopic dynamics of self-organized structures is the most important aspect in the description of complex living systems. The Belousov--Zhabotinsky (B--Z) reaction is in this respect a convenient testbed because it represents a prototype of chemical self-organization with a rich variety of emergent wave-spiral patterns. Using a multi-state stochastic hotchpotch model, we show here that the mesoscopic behaviour of the non-stirred B--Z reaction is both qualitatively and quantitatively susceptible to the description in terms of stochastic multilevel cellular automata. This further implies that the mesoscopic dynamics of the non-stirred B--Z reaction results from a delicate interplay between a) a maximal number of available states within the elementary time lag (i.e. a minimal time interval needed for demise of a final state) and b) an imprecision or uncertainty in the definition of state. If either the number of time lags is largely different from 7 or the maximal number of available states is smaller than 20,...

  3. Pattern of Adverse Drug Reactions in Children Attending the Department of Pediatrics in a Tertiary Care Center: A Prospective Observational Study

    Science.gov (United States)

    Digra, Kishour Kumar; Pandita, Aakash; Saini, GS; Bharti, Rajni

    2015-01-01

    AIM To study the pattern of various adverse drug reactions (ADRs) occurring in children attending the Department of Pediatrics, SMGS Hospital, Jammu over 1 year. SUBJECTS AND METHODS This was a prospective study, with study population of patients attending Department of Pediatrics over a period of 1 year. A structured format was used to enroll the participants. A pilot study was conducted to test the suitability of the format and feasibility of the study. The study was carried out to review various pattern of ADRs by using the Naranjo probability scale, and severity was assessed by using the Hartwig severity scale. ADRs were classified according to the classification used by the Adverse Drug Reaction Monitoring Center, Central Drugs Standard Control Organization, New Delhi, India. RESULTS In the present study, 104 patients were found to have developed acute drug reactions. Among these, 83.6% were type B, 14.42% type A, and 1.92% were type U. Furthermore, 25.96% ADRs were due to anticonvulsants, followed by antibiotics (22.11%), antipyretics (11.53%), vaccination (8.65%), steroids (6.73%), decongestants (5.67%), snake antivenom and antiemetics (3.84%), and fluids, insulin, and antacids (1.92%). The patients’ dermatological system was involved in 67.30%, followed by the central nervous system (CNS) in 11.53% patients. Renal system was involved in 6.73% patients. Cardiac, musculoskeletal, metabolic, and other systems were involved in 4.80%, 3.84%, 2.88%, and 0.96%, respectively. According to the Hartwig severity scale of ADRs, 64.4% patients had moderate ADRs, 29.8% patients had severe ADRs, and 5.76% had mild ADRs. In the present study, 64.4% patients expressed moderate severity, whereas 29.8% expressed high severity and 5.76% expressed mild ADRs. CONCLUSION ADRs were seen in 71% of the patients between 1 and 5 years of age, 26% in the age group of 5–10 years, and 3% were more than 10 years old. Anticonvulsants (25.96%) and antibiotics (22.11%) were responsible

  4. 11例双硫伦样反应的临床观察%Clinical Observation of 11 Disulfiram-like Reaction Cases

    Institute of Scientific and Technical Information of China (English)

    谢立雪

    2014-01-01

    目的:探讨双硫伦样反应的临床特点,提高临床医护人员的重视,避免误诊。方法对本院2011年4月至2013年4月收治的11例双硫伦样反应病例进行回顾性分析,总结其发生的原因、临床表现、治疗转归、误诊等。结果①患者发病前均有用药并有饮酒史,药物多为头孢菌素;②临床表现颜面潮红、视物模糊、出汗、口干、头痛、头晕、胸痛、胸闷、心悸、低血压、烦躁、气促、呼吸困难;③对症治疗后多于20~60 min临床症状缓解。结论应用可致双硫伦样反应的药物时,治疗过程前后应特别医嘱避免饮酒及应用乙醇制剂。%Objective To discuss the clinical responses of disulfiram-like reaction, raise the awareness of clinical medical staff and avoid misdiagnoses. Method A retrospective analysis of 11 disulfiram-like reaction cases in our hospital from April 2011 to April 2013 will be carried out and the causes, clinical manifestations, treatment effect and misdiagnoses of these cases will be summarized. Results ①All patients had a history of drinking and administering medicine, mostly cephalosporin, prior to the onset of illness.②Clinical manifestations include facial blushing, blurred vision, perspiration, dry mouth, headache, dizziness, chest pain, chest tightness, palpitation, low blood pressure, fidget, shortness of breath and dyspnea;③Remission of clinical manifestations appeared after 20-60 minutes' symptomatic treatment. Conclusion Doctors should advise patients to forbear from alcohol and other ethanol preparations before and after the treatment when prescribing medicines that may lead to disulfiram-like reaction for them.

  5. Sequential fission process observed in the reaction (16.7 MeV/u) sup 2 sup 3 sup 8 U + sup n sup a sup t sup . Au using mica as dielectric track detector

    CERN Document Server

    Shahzad, M I; Manzoor, S; Khan, H A

    1999-01-01

    The evidence of sequential fission has been found in the heavy-ion reaction (16.7 MeV/u) sup 2 sup 3 sup 8 U + sup n sup a sup t sup . Au, using muscovite mica as Dielectric Track Detector (DTD) placed in a 2 pi-geometry configuration. The reaction products originating from the interactions of sup 2 sup 3 sup 8 U ions with the atoms of gold were registered in the detector in the form of tracks and identified for performing a detailed kinematical analysis. For this purpose the spherical polar coordinates of the correlated tracks of the multipronged events have been analyzed on an event-by-event basis. Automatic, semi-automatic and manual measuring methods have been employed to collect and manipulate the track data. The known characteristics of binary and ternary events observed in the reaction have been used for the calibration of the detectors. The computed masses, Q-values and relative velocities of the reaction products determined in this analysis are compared with theoretical predictions based on sequentia...

  6. 甲磺酸左氧氟沙星注射液常见不良反应的观察及护理%Observation and nursing of common adverse reaction Levofloxacin Mesylate Injection

    Institute of Scientific and Technical Information of China (English)

    李雪芬

    2013-01-01

    Objective To explore the nursing countermeasures of reducing levofloxacin mesylate for injection adverse reactions . Methods Analysis of the static appearance drops of levofloxacin mesylate injection reaction in clinical observation .Results Levofloxacin mesylate for injection common drip speed and drug adverse reactions and drug related whether fasting .Conclusion Strengthen the nursing period of levofloxacin mesylate injection drug use ,can reduce or avoid its adverse reactions .%目的:探讨减轻甲磺酸左氧氟沙星注射液常见不良反应的护理对策。方法观察分析临床护理工作中静滴甲磺酸左氧氟沙星注射液出现的反应。结果甲磺酸左氧氟沙星注射液常见不良反应与药物的滴速及用药时是否空腹有关。结论加强甲磺酸左氧氟沙星注射液用药期间的护理,可以减少或避免其常见不良反应的发生。

  7. Competition between reaction and intramolecular energy redistribution in solution: observation and nature of nonstatistical dynamics in the ozonolysis of vinyl ethers.

    Science.gov (United States)

    Quijano, Larisa Mae M; Singleton, Daniel A

    2011-09-01

    Experimental product ratios in ozonolyses of alkyl vinyl ethers in solution do not fit with expectations based on statistical rate theories. The selectivity among cleavage pathways increases with the size of the alkyl group but to an extent that is far less than RRKM theory would predict. Trajectory studies account for the observed selectivities and support a mechanism involving a competition between cleavage of the primary ozonide and intramolecular vibrational energy redistribution. A statistical model is presented that assumes that RRKM theory holds for a molecular subset of the primary ozonides, allowing the rates of energy loss from the ozonides to be estimated from the observed product ratios. PMID:21812422

  8. Competition between Reaction and Intramolecular Energy Redistribution in Solution. Observation and Nature of Nonstatistical Dynamics in the Ozonolysis of Vinyl Ethers

    OpenAIRE

    Quijano, Larisa Mae M.; Singleton, Daniel A.

    2011-01-01

    Experimental product ratios in ozonolyses of alkyl vinyl ethers in solution do not fit with expectations from statistical rate theories. The selectivity among cleavage pathways increases with the size of the alkyl group but to an extent that is far less than RRKM theory would predict. Trajectory studies account for the observed selectivities and support a mechanism involving a competition between cleavage of the primary ozonide and intramolecular vibrational energy redistribution. An approxim...

  9. Observation of the Exclusive Reaction e^+e^-\\ to \\phi\\eta at \\sqrt{s}=10.58 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.

    2006-11-17

    The authors report the observation of e{sup +}e{sup -} {yields} {phi}{eta} near {radical}s = 10.58 GeV with 6.5 {sigma} significance in the K{sup +}K{sup -}{gamma}{gamma} final state in a data sample of 224 fb{sup -1} collected by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings. They measure the restricted radiation-corrected cross section to be {sigma}(e{sup +}e{sup -} {yields} {phi}{eta}) = 2.1 {+-} 0.4(stat) {+-} 0.1(syst) fb within the range |cos{theta}*| < 0.8, where {theta}* is the center-of-mass polar angle of the {phi} meson. The {phi} meson is required to be in the invariant mass range of 1.008 < m{sub {phi}} < 1.035 GeV/c{sup 2}. The radiation corrected cross section in the full cos {theta}* range is extrapolated to be 2.9 {+-} 0.5(stat) {+-} 0.1(syst) fb.

  10. Observation of hydrogen absorption/desorption reaction processes in Li-Mg-N-H system by in-situ X-ray diffractmetry

    International Nuclear Information System (INIS)

    The in-situ XRD measurements on dehydrogenation/rehydrogenation of the Li-Mg-N-H system were performed in this work. The ballmilled mixture of 8LiH and 3Mg(NH2)2 as a hydrogenated phase gradually changed into Li2NH as a dehydrogenated phase during heat-treatment at 200 oC in vacuum for 50 h. Neither Mg-related phases nor other intermediate phases were recognized in the dehydrogenated phase. With respect to the hydrogenation process, the dehydrogenated state gradually returned to the mixed phase of the LiH and Mg(NH2)2 without appearance of any intermediate phases during heat treatment at 200 oC under 5 MPa H2 for 37 h and during slow cooling down to room temperature through 24 h. In the hydrogenation process at 200 oC under 1 MPa H2, however, the growing up of the LiNH2 and LiH phase was observed in the XRD profiles before the 3Mg(NH2)2 and 8LiH phases were formed as the final hydrogenated state. This indicates that the LiNH2 and LiH phase essentially appears as an intermediate state in the Li-Mg-N-H system composed of 3Mg(NH2)2 and 8LiH

  11. Clinical observation of physiological and psychological reactions to electric stimulation of the amygdaloid nucleus and the nucleus accumbens in heroin addicts after detoxification

    Institute of Scientific and Technical Information of China (English)

    FANG Jun; GU Jian-wen; YANG Wen-tao; QIN Xue-ying; HU Yong-hua

    2012-01-01

    Background Stereotactic surgery has been used to treat heroin abstinence in China since 2000 by ablating the amygdaloid nucleus (AMY) and the nucleus accumbens (NAc),which also provides opportunity to identify the relationship between these nuclei and addiction.Our study aimed to explore the physiological and psychological effects of electrically stimulating the AMY and the NAc in herein addicts after detoxification by observing changes of heart rate,arterial pressure and occurrence of euphoria similar to heroin induced euphoria.Methods A total of 70 heroin addicts after detoxification were recruited,and 61 of them were eligible to be given stereotactic surgery for heroin abstinence.The operation was carried out after determining the coordinates of all target nucleuses,and stimulation was performed at the AMY and the NAc solely or jointly.Heart rate,arterial pressure and occurrence of euphoria similar to heroin induced euphoria were recorded and analyzed.Results The average heat rate was (66±10) beats/min before electric stimulation,and significantly increased to (84±14) beats/min during stimulation,and changed to (73±12) beats/min 10 minutes after stimulation.There was a significant elevation of the average arterial pressure from 83 mmHg before stimulation to 98 mmHg during the stimulation,and it then decreased to 90 mmHg after stimulation.Forty-three of the 61 patients showed intense euphoria similar to heroin induced euphoria.The largest number (118/186) of euphoric responses occurred when the AMY and the NAc were stimulated at the same time.Odds ratio was 5.4 (95% CI: 2.4-11.9,P <0.0001) to quantify the association.Results from a Logistic regression model showed a positive correlation between unilateral stimulation of either the AMY or NAC and induction of euphoria (OR >1 ),especially when the left AMY or left NAc was stimulated (P <0.05).Conclusions Our data are consistent with existing results that the AMY and the NAc are related to addiction

  12. Measurement of polarization observables in the {rvec d}+p{r_arrow}{rvec p}+p+n reaction at T{sub d}=2.0GeV

    Energy Technology Data Exchange (ETDEWEB)

    Belostotski, S.L.; Grebenyuk, O.G.; Kudin, L.G.; Nikulin, V.N. [St.-Petersburg Nuclear Physics Institute, 188350, Gatchina (Russia); Boudard, A.; Bonin, B.; Garcon, M.; Lombard, R.M.; Mayer, B.; Terrien, Y. [Service de Physique Nucleaire, CEA--Saclay, 91191 Gif-sur-Yvette (France); Boivin, M.; Tomasi-Gustafsson, E.; Yonnet, J. [Laboratoire National Saturne, CEA--Saclay, 91191 Gif-sur-Yvette (France); Youn, M.; Bhang, H.C. [Department of Physics, Seoul National University, Seoul 151-742 (Korea); Cheung, N.E.; Perdrisat, C.F. [College of William and Mary, Williamsburg, Virginia 23185 (United States); Punjabi, V. [Norfolk State University, Norfolk, Virginia 23504 (United States); Ero, J.; Fodor, Z.; Koncz, P.; Seres, Z. [KFKI Research Institute for Particle and Nuclear Physics, 1525 Budapest (Hungary)

    1997-07-01

    We have studied the deuteron breakup in the p(d,2p)n reaction at T{sub d}=2.0 GeV. In this experiment, the vector analyzing power A{sub Y}, the tensor analyzing power A{sub YY}, and the polarization of the forward scattered proton are measured close to the quasifree pp scattering kinematics. These observables are presented as a function of the neutron momentum ranging from 0.04 to 0.45 GeV/c in the rest frame of the deuteron. Marked deviations from the impulse approximation using conventional deuteron wave functions are observed. Corrections due to the multiple scattering, the final state interaction, and the {Delta} excitation are calculated in a model where the spin-isospin structure of the elementary amplitudes is treated rigorously. With this model, a reasonable account of the measured polarization observables is obtained. The global agreement with all observables is, however, not good enough that we can reliably discriminate between conventional wave functions. {copyright} {ital 1997} {ital The American Physical Society}

  13. From the (1B) Spectroscopic State to the Photochemical Product of the Ultrafast Ring-Opening of 1,3-Cyclohexadiene: A Spectral Observation of the Complete Reaction Path.

    Science.gov (United States)

    Pemberton, Christine C; Zhang, Yao; Saita, Kenichiro; Kirrander, Adam; Weber, Peter M

    2015-08-20

    All stages of the electrocyclic ring-opening of 1,3-cyclohexadiene (CHD) were observed by time-resolved photoionization-photoelectron spectroscopy. Spectra of the 1B state, previously unobserved using time-resolved methods, were obtained upon optical excitation using ultrashort laser pulses at 4.60 or 4.65 eV, followed by ionization with pulses at 3.81, 3.85, and 4.10 eV, revealing a 1B lifetime of 30 fs. In an experiment using 3.07 eV probe photons and a 4.69 eV pump, we observed a time-sequenced progression of Rydberg states that includes s, p, and d states of the series n = 3 to 6. The sequentiality of the Rydberg signals points to an ionization mechanism that captures the molecule on different points along the reaction path in 2A. A dynamic fit of the Rydberg signals, coupled with MS-CASPT2 calculations, reveals that as the wavepacket moves down the potential energy surface it acquires kinetic energy at a rate of 28 eV/ps before reaching the conical intersection to the 1A ground state. During the reaction, the terminal carbon atoms separate at a speed of 16 Å/ps. A deconvolution of the Rydberg signals from a broad feature assigned to structurally disperse 1,3,5-hexatriene (HT) shows the formation of the open-chain hexatriene structure with an onset 142 fs after the initial absorption of a pump photon. The experimental observations are discussed in the context of recent ultrafast X-ray scattering experiments and theoretical quantum dynamics simulations. PMID:26192201

  14. Measurement of polarization observables in the reaction {gamma}p{yields} p{pi}{sup 0}{pi}{sup 0} using linearly polarized photons with the CBELSA/TAPS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sokhoyan, Vahe

    2012-07-27

    The spectrum and the properties of baryon resonances can be studied using photons with energies appropriate to excite baryonic states. Double meson photoproduction allows access to cascading resonance decays via other excited states. Also, at higher energies the importance of the double meson photoproduction increases due to higher cross-sections in comparison to single meson photoproduction. To study baryon resonances, the measurement of polarization observables as well as the measurement of differential cross-sections plays a very important role. In this work the three-body polarization observables I{sup s}, I{sup c} and the respective twobody asymmetry {Sigma} were measured for the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0} in an incoming photon energy range of E{sub {gamma}} = 970 - 1650 MeV. The data were acquired with the CBELSA/TAPS experiment located at the ELSA accelerator in Bonn, using a linearly polarized photon beam impinging on a liquid hydrogen target. The observables I{sup s} and I{sup c} which occur in two-meson final states are measured for the first time in the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0}. The corresponding two-body asymmetry {Sigma} is measured in an extended energy range in comparison to already existing data. A comparison with theoretical models shows that the polarization observables provide valuable input to study resonance contributions and their decay modes. The D{sub 33}(1700) {yields} {Delta}{pi} decay is studied based on the comparison of the Bonn-Gatchina Partial Wave Analysis (PWA) predictions with the data. Furthermore, a comparison of the data with the Bonn-Gatchina PWA and the Fix isobar model predictions allows to distinguish between these two models. Additionally, band-like structures and peaks are observed in the mass ranges of {Delta}(1232), D{sub 13}(1520), F{sub 15}(1680), f{sub 0}(980) and f{sub 2}(1270) in the according Dalitz plots and invariant mass distributions. The contributions of these

  15. 替莫唑胺治疗胶质瘤不良反应的观察及分析%Observation on the Adverse Reactions of Temozolomide in the Treatment of Glioma

    Institute of Scientific and Technical Information of China (English)

    程浩峰; 何正文; 任年军; 杨杰

    2014-01-01

    Objective To analyze the adverse reactions of temozolomide (TMZ) for the treatment of glioma so as to provide a basis for clinical rational administration. Methods The patients diagnosed with glioma and treated by TMZ regimen in our hospital were analyzed, including whether giving the patients temozolomide concurrent chemoradiotherapy, and blood routine examination during chemotherapy and so on. The adverse reactions of the patients were assessed according to the NCI-CTC2.0. Results 78 patients were enrolled, with the age of 22-79 (average 45), including 43 males and 35 females. Hematologic toxicity was observed in 12 cases (15.4%), digestive system adverse reactions in 35 cases (44.9%). Adverse reactions were more frequently observed in females than in males and in cases with concurrent chemoradiotherapy than those with TMZ chemotherapy alone. Conclusion TMZ has less adverse reactions and good tolerance. But female patients and the patients with concurrent chemoradiotherapy should be closely monitored. And how to control its adverse reactions is worthy to be explored.%分析替莫唑胺治疗胶质瘤不良反应的情况,为临床合理用药提供依据。方法对该院确诊的胶质瘤且使用替莫唑胺化疗患者进行分析,包括是否进行替莫唑胺同步放化疗,化疗期间血常规检查等。根据药物的不良反应判断标准NCI-CTC2.0对患者的不良反应进行判定。结果收入符合病例78例,年龄22~79岁,中位年龄为45岁,男性43例,女性35例。血液学毒性出现12例(15.4%),消化系统不良反应出现35例(44.9%)。其中,女性不良反应发生率比男性高,同步放化疗患者比单纯替莫唑胺化疗者高。结论替莫唑胺的不良反应较少,耐受性好,但应密切监测女性患者以及进行替莫唑胺同步放化疗的患者,如何控制其不良反应,还值得探讨。

  16. RILEM TC ISR Summer 2015 Activity Report

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, Yann [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    With aging infrastructures, instances of Alkali Silica Reaction (ASR) and Delayed Ettringite Formation (DEF), broadly covered under the term Internal Swelling Reaction (ISR), are increasingly being detected. They have been observed in bridges, dams, and most recently in nuclear power plants. Concrete swelling may result in bridge partial failure, dams with structural cracks and misaligned turbine shafts, and locked slice gates. For nuclear reactors micro-cracks may cause increased gas permeability which will jeopardize the containment integrity and may decrease the residual structural resistance under accidental loading. This TC, which limits its activity to structures with known expansive concrete, seeks to address two complementary but fundamental questions: a) What is the kinetics of the reaction and b) How would it affect the integrity of the structure (serviceability and strength) and thus establish a science based prognostic to the structure owner.

  17. Structural modelling of ASR-affected concrete: The approach developed in the PAT-ASR project

    NARCIS (Netherlands)

    Esposito, R.; Hendriks, M.A.N.

    2013-01-01

    The Alkali-Silica Reaction is a harmful reaction which can compromise the integrity and capacity of concrete structures. Due to its nature, a multiscale material model has been chosen to perform structural analyses. The model aims to couple the chemical and mechanical effects in order to characteriz

  18. Clinical observation and nursing on adverse reactions of interferon when treating chronic hepatitis B%干扰素治疗慢性乙型肝炎不良反应的临床观察及处理措施

    Institute of Scientific and Technical Information of China (English)

    赵斌; 赵恢; 刘丽丽

    2012-01-01

    Objective To observe the adverse reactions of interferon in the treatment for chronic hepatitis B, discuss the nursing measures in order to reduce adverse reactions, improve the compliance of interferon treatment and ensure the patients had interferon treatment full dose and full process. Methods 78 cases of patients sufferring chronic hepatitis B with interferon treatment were collected from January,2011 to July,2012,to observe adverse reactions and to take effective nursing measures. Results Of the 78 patients sufferring chronic hepatitis B,64. 1 percent of them had the influenza-like symptom,40 percent of them had fatigue,32. 5 percent of them had no appetite and nausea, 19. 23 percent of them had ahypnosis,8 percent of them had fidgets,6. 41 percent of them had lipsotrichia. The patients can had interferon treatment full dose and full process after the nursing management. Conclusion Adverse reactions of interferon can be predicted and treated. The patients could be treated by interferon successfully through appropriate nursing measures.%目的 观察干扰素在治疗慢性乙型肝炎过程中的不良反应,探讨减轻不良反应的护理措施,提高对慢性乙型肝炎患者干扰素治疗的依从性,保证患者能足量足疗程使用干扰素.方法 对2011年1月-2012年7月我院收治的78例慢性乙型肝炎患者在干扰素治疗过程中出现的不良反应进行观察,并采取有效的护理措施和护理干预.结果 78例患者中出现流感样综合征的50例,占64.1%;乏力32例,占40%;食欲不振、恶心25例,占32.5%;失眠15例,占19.23%;烦躁不安6例,占8%;脱发5例,占6.41%.给予护理措施干预后,患者均能足量足疗程完成干扰素的治疗.结论 干扰素的不良反应是可预见和可处理的,通过恰当的护理干预,可以帮助患者顺利完成干扰素治疗的整个过程.

  19. Observation on Stress Reaction of Patients before Elective Operation%择期手术患者手术前应激反应的观察和分析

    Institute of Scientific and Technical Information of China (English)

    魏虹

    2014-01-01

    目的探讨择期手术患者手术前应激反应的观察和分析。方法通过Zung编制的焦虑自评量表对患者的焦虑程度进行评定,比较各组患者同样的应激因素对不同的个体引起的不同反应。结果各组手术患者在手术前应激情况下都存在明显的心理问题,通过分析进行心理干预,可缓解心理压力,提高手术应激性。结论要重视手术患者手术前应激反应,解除患者对手术的恐惧和不安心理,减少手术后并发症,提高手术成功率。%Objective Research on the observation and analysis of the stress reaction of patients before the elective operation.Methods Evaluate the anxious intensity of operation patients through the anxiety self-assessment table.Results Every operation patient has obvious psychological problems under the stressful situation before the operation. Through analyzing, the psychological pressure can be relieved and the operation emergency can be improved by psychology intervening. Conclusion The analyzing of the stress reaction of patients before the operation can help remove patients' fear of operation and anxiety, reduce complication before the operation, and improve the success rate of the operation.

  20. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2010-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...

  1. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2011-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...

  2. Nuclear structure, nuclear reaction

    OpenAIRE

    Etchegoyen, Maria Cristina Berisso de.; Sinclair, D.; Dr. D. Sinclair

    1982-01-01

    In this thesis, particle- particle angular correlations for reactions in non-zero degree geometry and with non-zero spin nuclei are performed and found to be a valuable tool for spin determination, (d-α) angular correlations in the reaction process 14N(6Li,d)18F* (α)14N are measured for three high excited states in 18F with a 6Li beam of 36MeV. Spins and parities for two of the observed states are determined, and in agreement with theoretical predictions, these states are s...

  3. Electrochemical reactions and ionization processes

    OpenAIRE

    Girault, Hubert; Liu, Baohong; Qiao, Liang; Bi, Hongyan; Prudent, Michel; Lion, Niels; Abonnenc, Mélanie

    2010-01-01

    Electrochemical or photo-electrochemical reactions in both electrospray ionization and laser desorption ionization are discussed stressing the role of the electrode reaction in influencing the ionization process. In particular, upon application of a high voltage during electrospray ionization, the emitter includes a working electrode, where redox reactions are observed, such as electro-generation of benzoquinone and metal ions. In contrast, the target plate in laser-induced desorption ionizat...

  4. A multiscale theoretical methodology for the calculation of electrochemical observables from ab initio data: Application to the oxygen reduction reaction in a Pt(1 1 1)-based polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    In this work we present a multiscale theoretical methodology that scales up ab initio calculated data into elementary kinetic models in order to simulate Polymer Electrolyte Membrane Fuel Cells (PEMFC) transient operation. Detailed Density Functional Theory (DFT) calculations are performed on a model Pt(1 1 1) surface to determine the elementary kinetic rates of the Oxygen Reduction Reaction (ORR) mechanism at a Pt-based PEMFC cathode. These parameters include the effect of surface coverage on the activation barriers and are implemented into a Mean Field model describing the behavior of the electric field and charge distribution at the nanoscale interfacial vicinity to the catalyst, which is in turn coupled with microscale and mesoscale level models describing the charge and reactants and water transport phenomena across the cell. The impact of two possible ORR mechanisms on the simulated i–V curves is investigated: a first route connected with the dissociative adsorption of molecular oxygen on Pt(1 1 1), a second route related to the formation and the transformation of OOH surface species. The similarities and differences of the associated calculated i–V responses for each of these routes and the consequences on the interpretation of electrochemical observables at the cell level are discussed.

  5. Properties and decay modes of hot nuclei produced in the reaction: {sup 36}Ar on {sup 58}Ni and detected with INDRA device; Proprietes et modes de desexcitation des noyaux chauds observes dans la reaction {sup 36}Ar sur {sup 58}Ni avec le detecteur INDRA

    Energy Technology Data Exchange (ETDEWEB)

    Nalpas, L. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee]|[Paris-11 Univ., 91 - Orsay (France)

    1997-01-01

    Hot nuclei are formed in heavy ion collisions covering the Fermi energy domain. According to the excitation energy deposited into these nuclei, several de-excitation processes can be observed, in particular the emission of complex fragments (Z {>=} 3) which remains poorly understood. The GANIL facility offers the possibility to cover the excitation function for the Ar on Ni reaction over a broad energy range from 32 to 95 MeV/u where the hot nuclei evolve from classical `evaporation` to complete `vaporization` into light particles (neutrons, isotopes of H, He). The study of reaction mechanisms shows that from peripheral to central collisions the total cross section is dominated by binary dissipative collisions. Both partners coming from well-characterized events with the INDRA detector are reconstructed using the `Minimum Spanning Tree` method. Thus excitation energy up to 20 MeV/A are reached in the most violent collisions at the highest bombarding energy. The deposited energy is not shared in the mass ratio between the quasi-projectile and the quasi-target, the quasi-projectile being hotter. For total excitation energies ranging roughly from 2 to 8 MeV/A, the proportion of `multifragmentation` events increases to reach a plateau at about 10 MeV/A due to the rising probability to have complete `vaporization` of the system above 8 MeV/A. The steady increase of the temperature extracted from the double isotopic He-Li ratios with excitation energy for the quasi-projectile suggests a progressive evolution of the de-excitation processes as predicted by statistical models. No signal of first order liquid-gas phase transition is seen in our data. (author) 124 refs.

  6. Novel shear capacity testing of ASR damaged full scale concrete bridge

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Hansen, Søren Gustenhoff; Barbosa, Ricardo Antonio;

    2014-01-01

    A large number of concrete bridges in Denmark have to undergo wide-ranging maintenance work to prevent deterioration due to aggressive Alkali Silica Reaction (ASR). This destructive mechanism results in extensive cracking which is believed to affect the load carrying capacity of the structure...

  7. Degradation of the mechanical properties in ASR-affected concrete : overview and modeling

    NARCIS (Netherlands)

    Esposito, R.; Hendriks, M.A.N.

    2012-01-01

    The Alkali-Silica Reaction (ASR) can generate harmful effects in the concrete structures. In this paper the degradation of the mechanical properties of ASR-affected concrete is studied by comparing the experimental results available in literature. An overview of the macroscopic material modelling ap

  8. Observation of nursing and influence by esmolol on tracheal intubation cardiovascular reaction%艾司洛尔对气管插管心血管反应的影响及护理观察

    Institute of Scientific and Technical Information of China (English)

    陈美珠; 许惠春

    2016-01-01

    ObjectiveTo evaluate preventive effect by esmolol for tracheal intubation cardiovascular reaction.MethodsA total of 80 ASA grade Ⅰ~Ⅱ patients receiving gynecological laparoscopic operation under general anesthesia were randomly divided into control group (group C) and esmolol group (group E), with 40 cases in each group. They received respectively 5 ml normal saline and 5 ml (1 mg/kg) esmolol in 3 min before tracheal intubation through intravenous injection. Observation was made on changes of mean arterial pressure (MAP) and heart rate (HR) in 1, 3, 5 min after intubation.ResultsIn 1 and 3 min after tracheal intubation, group E had all lower MAP and HR than group C, and their difference had statistical significance (P<0.05). ConclusionIntravenous injection of esmolol by 1 mg/kg in 3 min before tracheal intubation can remarkably reduce tracheal intubation cardiovascular reaction, and it is helpful for nursing in tracheal intubation.%目的:评估艾司洛尔对气管插管心血管反应的预防作用。方法80例ASA Ⅰ~Ⅱ级、全身麻醉下行妇科腹腔镜手术患者,随机分为对照组(C组)和艾司洛尔组(E组),每组40例,分别于气管插管前3 min缓慢静脉推注生理盐水5 ml和艾司洛尔5 ml(1 mg/kg),观察插管后1、3、5 min的平均动脉压(MAP)、心率(HR)变化。结果气管插管后1、3 min E组 MAP和HR 均显著低于C组,差异有统计学意义(P<0.05)。结论气管插管前3 min缓慢静脉推注艾司洛尔1 mg/kg,显著减轻了气管插管的心血管反应,有利于气管插管的护理。

  9. Polarization phenomena in collinear reactions

    Science.gov (United States)

    Moravcsik, Michael J.; Arash, Firooz

    1985-06-01

    It is shown for a collinear reaction containing four particles with arbitrary spins which amplitudes remain nonzero and how they are related to the observables. In terms of primary observables all submatrices relating products of amplitudes to observables either vanish or turn into one-by-one submatrices, except the 8i types which may turn into three-by-three submatrices, but these latter submatrices are mostly avoidable when determining amplitudes. In terms of the secondary observables the 1M and 2i submatrices are slightly larger. Specifically, it is shown that in collinear reactions all observables in which only one particle is polarized (no matter how) vanish. Since reactions at very high energies are expected to be predominantly very close to being collinear, the smallness of such observables in such reactions can be expected on general grounds but polarization effects involving observables with more than one polarized particle can very well be very large. An iterative approximation method for the polarization analysis of reactions at very high energies is suggested. The results of this paper are also applicable to all models in which helicity conservation holds, since they are, for all t values, formally identical with collinear reactions.

  10. Polarization phenomena in collinear reactions

    International Nuclear Information System (INIS)

    It is shown for a collinear reaction containing four particles with arbitrary spins which amplitudes remain nonzero and how they are related to the observables. In terms of primary observables all submatrices relating products of amplitudes to observables either vanish or turn into one-by-one submatrices, except the 8/sub i/ types which may turn into three-by-three submatrices, but these latter submatrices are mostly avoidable when determining amplitudes. In terms of the secondary observables the 1/sub M/ and 2/sub i/ submatrices are slightly larger. Specifically, it is shown that in collinear reactions all observables in which only one particle is polarized (no matter how) vanish. Since reactions at very high energies are expected to be predominantly very close to being collinear, the smallness of such observables in such reactions can be expected on general grounds but polarization effects involving observables with more than one polarized particle can very well be very large. An iterative approximation method for the polarization analysis of reactions at very high energies is suggested. The results of this paper are also applicable to all models in which helicity conservation holds, since they are, for all t values, formally identical with collinear reactions

  11. Cellular basis of the immunohematologic defects observed in short-term semiallogeneic B6C3F1→C3H chimeras: evidence for host-versus-graft reaction initiated by radioresistant T cells

    International Nuclear Information System (INIS)

    Lethally irradiated C3Hf mice reconstituted with a relatively low dose (2 x 106) of B6C3F1 bone marrow cells (B6C3F1→C3Hf chimeras) frequently manifest immunohematologic deficiencies during the first month following injection of bone marrow cells. They show slow recovery of antibody-forming potential to sheep red blood cells (SRBC) as compared to that observed in syngeneic (C3Hf→C3Hf or B6C3F1→B6C3F1) chimeras. They also show a deficiency of B-cell activity as assessed by antibody response to SRBC following further reconstitution with B6C3F1-derived thymus cells 1 week after injection of bone marrow cells. A significant fraction of B6C3F1→C3Hf chimeras was shown to manifest a sudden loss of cellularity of spleens during the second week following injection of bone marrow cells even though cellularity was restored to the normal level within 1 week. The splenic mononuclear cells recovered from such chimeras almost invariably showed strong cytotoxicity against target cells expressing donor-type specific H-2 antigens (H-2/sup b/) when assesed by 51Cr-release assay in vitro. The effector cells responsible for the observed anti-donor specific cytotoxicity were shown to be residual host-derived T cells. These results indicate strongly that residual host T cells could develop anti-donor specific cytotoxicity even after exposure to a supralethal dose (1050 R) of radiation and that the immunohematologic disturbances observed in shortterm F1 to parent bone marrow chimeras (B6C3F1→C3Hf) were due to host-versus-graft reaction (HVGR) initiated by residual host T cells. The implication of these findings on the radiobiological nature of the residual T cells and the persistence of potentially anti-donor reactive T-cell clones in long-surviving allogeneic bone marrow chimeras was discussed

  12. Bulk Nuclear Properties from Reactions

    OpenAIRE

    Danielewicz, P.

    2002-01-01

    Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

  13. 养肺消疹汤治疗EGFR-TKIs药物相关不良皮肤反应的临床观察%Clinical observation on treatment of EGFR-TKIs-related adverse skin reactions with Yangfei Xiaozhen Tang

    Institute of Scientific and Technical Information of China (English)

    孙韬; 杨婕; 胡凯文

    2013-01-01

    Objective To observe the curative effect of Yangfei Xiaozhen Tang on EGFR-TKIs-related adverse skin reactions. Methods The patients (n=50) with non-small-cell lung cancer (NSCLC) and rash after taking EGFR-TKIs were randomly divided into two groups and respectively treated with Yangfei Xiaozhen Tang used orally combining washing (treatment group, n=25) and external pimecrolimus ointment (control group, n=25). The changes of rash grading, TCM syndromes and relief of quality of life (QOL) were observed in two groups. Results In treatment group, the rash grading was improved at all time points. After treatment for 30 days, the effective rate was 72%in treatment group and 44%in control group. The recovery rate of TCM syndromes was 92%in treatment group and 36%in control group after treatment. The scores of QOL were superior in treatment group after treatment for 14 days and 30 days. Conclusion Yangfei Xiaozhen Tang used orally combining washing has good curative effect on EGFR-TKIs-related adverse skin reactions.%目的:观察养肺消疹汤治疗表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKIs)药物相关不良皮肤反应的疗效。方法将50例服用EGFR-TKIs后出现皮疹的非小细胞肺癌患者随机分为2组各25例,治疗组采用养肺消疹汤口服联合外洗进行治疗,对照组采用吡美莫司软膏外用的方法进行治疗,观察各组皮疹分级、中医证候、生活质量改善情况。结果治疗组在各个检测时点皮疹分级均有显著改善,且优于对照组;治疗30 d后治疗组、对照组皮疹治疗有效率分别为72%与44%;治疗前后治疗组与对照组中医证候改善率分别为92%与36%;治疗14,30 d后2组生活质量评分治疗组有显著优势。结论养肺消疹汤口服联合外洗对EGFR-TKIs药物相关不良皮肤反应具有良好疗效。

  14. Moxibustion with Pressing Pills at Ear Points to Prevent Cisplatin after Treatment Gastrointestinal Reaction of Clinical Observation%艾灸配合耳穴压豆预防化疗后胃肠反应临床研究

    Institute of Scientific and Technical Information of China (English)

    刘勇; 程俊; 张琼; 邹文娟; 应坚; 邱敏

    2012-01-01

    目的 观察艾灸配合耳穴压豆预防化疗所致胃肠反应的疗效.方法 将120例进行含顺铂和(或)阿霉素化疗的恶性肿瘤患者按照数字随机法分为治疗组和对照组各60例,两组患者在化疗前均给予甲磺酸托烷司琼注射液+地塞米松注射液静滴并在化疗后予甲氧氯普胺注射液肌注,治疗组患者在化疗前5d给予艾灸配合耳穴压豆,观察化疗期间两组患者恶心、呕吐、腹泻、口腔炎及化疗后20 d的体质量变化.结果 治疗组恶心、呕吐、腹胀、纳差发生率低于对照组,腹泻、便秘发生率比较差异无显著性,生活质量评分的增加及稳定率、体重的增加及稳定率均优于对照组.结论 艾灸配合耳穴压豆预防顺铂和(或)阿霉素引起的胃肠反应疗效可靠.%Objective: To observe the clinical of moxibustion combined with pressing pills at ear points in preventing gastrointestinal reaction caused by chemotherapy treatment. Methods: 120 examples including cisplatin and (or) doxorubicin chemotherapy in patients with malignant tumor were divided into treatment group and control group according to the table of random number method ,and every group had 60 patients.Both groups were given tropisetron mesylate injection and intravenous drip of dexamethasone injection before chemotherapy,and were given metoclopramide injection intramuscular after chemotherapy, treatment group were given moxibustion combined with pressing pills at ear points before chemotherapy. Some outcomes were observed during the treatment of two groups of patients with stomatitis and weight changes in the 20 days after chemotherapy. Results: treatment group nausea,vomiting,abdominal distension,anorexia rate lower than those of the control group;No significant difference in the incidence of diarrhea, constipation. Increase in quality of life scores and steady rate, increase in weight and stable rates are better than the control group. Conclusion: moxibustion

  15. A new study of the {sup 22}Ne(p, γ){sup 23}Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cavanna, F.; Corvisiero, P.; Ferraro, F.; Prati, P. [Universita di Genova, Dipartimento di Fisica, Genova (Italy); INFN, Sezione di Genova (Italy); Depalo, R. [INFN, Sezione di Padova, Padova (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Menzel, M.L.; Anders, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Technische Universitaet Dresden, Dresden (Germany); Aliotta, M.; Bruno, C.G.; Davinson, T.; Scott, D.A. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Bemmerer, D.; Szuecs, T. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Broggini, C.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Caciolli, A. [INFN, Sezione di Padova, Padova (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Di Leva, A.; Imbriani, G. [Universita degli Studi di Napoli Federico II, Dipartimento di Fisica, Napoli (Italy); INFN, Sezione di Napoli (Italy); Elekes, Z.; Fueloep, Z.; Gyuerky, G.; Somorjai, E. [Institute of Nuclear Research of the Hungarian Academy of Sciences (MTA ATOMKI), Debrecen (Hungary); Formicola, A.; Junker, M. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gervino, G. [Universita di Torino, Dipartimento di Fisica Sperimentale, Torino (Italy); INFN, Sezione di Torino (Italy); Guglielmetti, A.; Trezzi, D. [Universita degli Studi di Milano, and INFN, Sezione di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [Osservatorio Astronomico di Collurania, Teramo (Italy); Ruhr-Universitaet Bochum, Bochum (Germany); Strieder, F. [Ruhr-Universitaet Bochum, Bochum (Germany); Collaboration: LUNA Collaboration

    2014-11-15

    The {sup 22}Ne(p,γ){sup 23}Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle is active in asymptotic giant branch stars as well as in novae and contributes to the nucleosythesis of neon and sodium isotopes. In order to reduce the uncertainties in the predicted nucleosynthesis yields, new experimental efforts to measure the {sup 22}Ne(p,γ){sup 23}Na cross section directly at the astrophysically relevant energies are needed. In the present work, a feasibility study for a {sup 22}Ne(p,γ){sup 23}Na experiment at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator deep underground in the Gran Sasso laboratory, Italy, is reported. The ion-beam-induced γ-ray background has been studied. The feasibility study led to the first observation of the E{sub p}=186 keV resonance in a direct experiment. An experimental lower limit of 0.12 x 10{sup -6} eV has been obtained for the resonance strength. Informed by the feasibility study, a dedicated experimental setup for the {sup 22}Ne(p,γ){sup 23}Na experiment has been developed. The new setup has been characterized by a study of the temperature and pressure profiles. The beam heating effect that reduces the effective neon gas density due to the heating by the incident proton beam has been studied using the resonance scan technique, and the size of this effect has been determined for a neon gas target. (orig.)

  16. Post-marketing surveillance of the safety profile of iodixanol in the outpatient CT setting. A prospective, multicenter, observational study of patient risk factors, adverse reactions and preventive measures in 9953 patients

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Frank Hugo Heinz [Radiology and Nuclear Medicine Center, Ludwigshafen (Germany)

    2014-11-15

    Non-interventional study in outpatient, contrast-enhanced CT: 1. to determine the extent of preventive measures for risk reduction of adverse drug reactions after contrast-enhanced CT examinations. 2. to prospectively determine the incidence and severity of adverse drug reactions occurring after administration of the iso-osmolar contrast medium iodixanol. 3. to determine a possible influence of preventive measures on the incidence/severity of adverse drug reactions. Evaluable documentation was provided for 9953 patients from 66 radiology centers across Germany. Patient characteristics, aspects of iodixanol administration, and adverse events with an at least 'possible' relationship were documented on a standardized case report form (CRF) and were evaluated up to seven days after contrast medium administration. About 55.5% of patients showed one or more risk factors (e.g. impaired renal function 4.4%, diabetes mellitus 8.5%, hypertension 20.6%). One third of the sites did not implement any preventive measures. Patients with a known risk for an allergy-like reaction were more likely to receive pharmacologic preventive treatment (0.5-50.5%). Oral hydration was the main preventive measure in patients with renal risk factors (<8%) followed by intravenous hydration (1%). Adverse drug reactions, mainly hypersensitivity reactions, occurred in 77 patients (0.74%), but were classified as serious in only 3 patients (0.03%). No statistically significant correlation between risk factors, preventive measures, and adverse reactions could be found. The use of preventive measures for CT examinations in this outpatient setting was generally low with risk patients being pre-medicated more often, depending on their history. In the routine outpatient setting, iso-osmolar iodixanol was very well tolerated in almost 10 000 patients undergoing diagnostic CT. The rate of acute and delayed adverse reactions was low. No correlation could be found between risk factors, preventive

  17. Chain reaction

    International Nuclear Information System (INIS)

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  18. Fly and bottom ashes from biomass combustion as cement replacing components in mortars production: rheological behaviour of the pastes and materials compression strength.

    Science.gov (United States)

    Maschio, Stefano; Tonello, Gabriele; Piani, Luciano; Furlani, Erika

    2011-10-01

    In the present research mortar pastes obtained by replacing a commercial cement with the equivalent mass of 5, 10, 20 and 30 wt.% of fly ash or bottom ash from fir chips combustion, were prepared and rheologically characterized. It was observed that the presence of ash modifies their rheological behaviour with respect to the reference blend due to the presence, in the ashes, of KCl and K2SO4 which cause precipitation of gypsum and portlandite during the first hydration stages of the pastes. Hydrated materials containing 5 wt.% of ash display compression strength and absorption at 28 d of same magnitude as the reference composition; conversely, progressive increase of ash cause a continuous decline of materials performances. Conversely, samples tested after 180 d display a marked decline of compression strength, as a consequence of potassium elution and consequent alkali-silica reaction against materials under curing.

  19. Conceptual model for concrete long time degradation in a deep nuclear waste repository

    International Nuclear Information System (INIS)

    This report is mainly a state-of-the-art report of concrete long time durability in the environment expected in a deep site underground nuclear waste repository in Swedish crystalline bedrock. The report treats how the concrete and the surrounding groundwater will interact and how they will be affected by cement chemistry, type of aggregate etc. The different mechanisms for concrete alteration treated include sulphate attack, carbonation, chloride attack, alkali-silica reaction and leaching phenomena. In a long time perspective, the chemical alterations in concrete is mainly governed by the surrounding groundwater composition. After closure the composition of the groundwater will change character from a modified meteoric to a saline composition. Therefore two different simulated groundwater compositions have been used in modelling the chemical interaction between concrete and groundwater. The report also includes a study of old and historical concrete which show observations concerning recrystallization phenomena in concrete. 72 refs, 39 figs

  20. Reaction of nitrile pollutants in high temperature water: Reaction pathway analysis and kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Izzo, B.; Harrell, C.; Klein, M.T. [Univ. of Delaware, Newark, DE (United States); LaMarca, C. [E.I. du Pont de Nemours & Co., Wilmington, DE (United States)

    1996-12-31

    The reaction chemistry of acetonitrile and benzonitrile in High Temperature Water (HTW) was investigated. The reaction products were the associated amides and carboxylic acids. A kinetic model incorporating two autocatalytic steps captured the kinetics observed. The optimized rate constants highlighted differences in the reaction chemistry of aliphatic and aromatic nitrites at these reaction conditions. 6 refs., 3 figs., 2 tabs.

  1. Observer's observables. Residual diffeomorphisms

    CERN Document Server

    Duch, Paweł; Świeżewski, Jedrzej

    2016-01-01

    We investigate the fate of diffeomorphisms when the radial gauge is imposed in canonical general relativity. As shown elsewhere, the radial gauge is closely related to the observer's observables. These observables are invariant under a large subgroup of diffeomorphisms which results in their usefulness for canonical general relativity. There are, however, some diffeomorphisms, called residual diffeomorphisms, which might be "observed" by the observer as they do not preserve her observables. The present paper is devoted to the analysis of these diffeomorphisms in the case of the spatial and spacetime radial gauges. Although the residual diffeomorphisms do not form a subgroup of all diffeomorphisms, we show that their induced action in the phase space does form a group. We find the generators of the induced transformations and compute the structure functions of the algebras they form. The obtained algebras are deformations of the algebra of the Euclidean group and the algebra of the Poincar\\'e group in the spat...

  2. Multinucleon transfer reactions

    International Nuclear Information System (INIS)

    Nuclear reactions induced by complex nuclei are studied. The description of the single neutron transfer is used to show some aspect of the theoretical treatment of transfer reactions and rules concerning the dependence of cross sections on quantum numbers of the initial and final channels are deduced. Strongly excited states of 20Ne, 19F, sup(16,17)0, 15N were studied experimentally by using different projectile-target combinations in the four-particle, eight-particle and ten-particle transfer reactions, leading to the some final nuclei. Obtained results are discussed. In addition, studies of the projectile break-up phenomenon were performed. The dissociation of 6Li and 7Li projectiles was investigated in reactions on Pb, Sn and Ni nuclei. These nuclei were chosen to allow measurements at one incident energy below, above and at the Coulomb barrier. The observed spectra indicate that the process proceeds primarily via the resonance level but the shape deviates from the shape which was calculated assuming isotropic decay of the excited 6Li in its center of mass system. The investigations of the elastic scattering turned out to be more fruitful and allowed to define better the Coulomb barrier for the 6Li-target system. (S.B.)

  3. Cluster knockout reactions

    Indian Academy of Sciences (India)

    Arun K Jain; B N Joshi

    2014-04-01

    Cluster knockout reactions are expected to reveal the amount of clustering (such as that of , d and even of heavier clusters such as 12C, 16O etc.) in the target nucleus. In simple terms, incident medium high-energy nuclear projectile interacts strongly with the cluster (present in the target nucleus) as if it were existing as a free entity. Theoretically, the relatively softer interactions of the two outgoing particles with the residual nucleus lead to optical distortions and are treated in terms of distorted wave (DW) formalism. The long-range projectile–cluster interaction is accounted for, in terms of the finite range (FR) direct reaction formalism, as against the more commonly adopted zero-range (ZR) distorted wave impulse approximation (DWIA) formalism. Comparison of the DWIA calculations with the observed data provide information about the momentum distribution and the clustering spectroscopic factor of the target nucleus. Interesting results and some recent advancements in the area of (, 2) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out.

  4. Azlactone Reaction Developments.

    Science.gov (United States)

    de Castro, Pedro P; Carpanez, Arthur G; Amarante, Giovanni W

    2016-07-18

    Azlactones (also known as oxazolones) are heterocycles usually employed in the stereoselective synthesis of α,α-amino acids, heterocycles and natural products. The versatility of the azlactone scaffold arises from the numerous reactive sites, allowing its application in a diversity of transformations. This review aims to cover classical and recent applications of oxazolones, especially those involving stereoselective processes. After a short introduction on their structures and intrinsic reactivities, dynamic kinetic resolution (DKR) processes as well as reactions involving stereoselective formation of a new σ C-C bond, such as alkylation/allylation/arylation, aldol, ene, Michael and Mannich reactions will be exposed. Additionally, cycloadditions, Steglich rearrangement and sulfenylation reactions will also be discussed. Recent developments of the well-known Erlenmeyer azlactones will be described. For the most examples, the proposed mechanism, activation modes and/or key reaction intermediates will be exposed to rationalize both the final product and the observed stereochemistry. Finally, this review gives an overview of the synthetic utility of oxazolones. PMID:27245128

  5. EXERCISE AND REACTION TIMES

    Directory of Open Access Journals (Sweden)

    Varun

    2015-03-01

    Full Text Available OBJECTIVES: Physical exercise provides multiple benefits to an individual. It is known that exercising regularly can prevent coronary heart disease, hypertension and obesity and improve flexibility. The effect of exercise on visual reaction time needs to be studied, a s the existing data on the benefit of aerobic exercise on psychomotor functions is insufficient. MATERIALS AND METHODS: Online Visual reaction time is measured before and after exercise. Subjects were instructed to run on the spot with a springy step in ex aggerated motion for 50 to 60 counts at 2 counts per second, maintaining a constant rhythm. RESULTS: We observed that reaction time was significantly lower after performance of exercise. Individuals reported improved mental alertness, feel good factor, bet ter mood and increase circulation. CONCLUSION: Improving reaction times in sports can help the athlete to optimize his performance in making decisions and increasing attention span for example getting off the starting blocks sooner or successfully making c ontact with the ball. In addition this study shows that use of physical exercise helps improve cognitive function. Exercise proves to be a cheap non pharmacological alternative to improve cognitive performance.

  6. Crossed beam reaction of the cyanogen radical, CN(X 2Σ+), with acetylene, C2H2(X 1Σg+): Observation of cyanoacetylene, HCCCN(X 1Σ+)

    Science.gov (United States)

    Huang, L. C. L.; Lee, Y. T.; Kaiser, R. I.

    1999-04-01

    The chemical dynamics to cyanoacetylene, HCCCN(X 1Σ+), formation via the neutral-neutral reaction of cyanogen, CN(X 2Σ+), with acetylene, C2H2(X 1Σg+), is investigated in a crossed molecular beams experiment at a collision energy of 21.1 kJ mol-1. The laboratory angular distribution and time-of-flight spectra of the HCCCN product are recorded at m/e=51 and 50. Forward-convolution fitting of our data reveals that the reaction dynamics are governed by an initial attack of the CN radical to the π electron density of the acetylene molecule to form a HCCHCN collision complex on the 2A' surface. The four heavy atoms are rotating in plane almost perpendicular to the total angular momentum vector J around the C axis of the complex which undergoes C-H bond rupture through a tight transition state to HCCCN and H. The H atom is emitted almost perpendicular to the HCCCN axis to yield a nearly "sideways" peaking of T(θ). The explicit identification of the cyanoacetylene reaction product represents a solid background for the title reaction to be included with more confidence in reaction networks modeling the chemistry in dark, molecular clouds, outflow of dying carbon stars, hot molecular cores, as well as the atmosphere of hydrocarbon rich planets and satellites such as the Saturnian moon Titan.

  7. Observation and nursing experience of adverse reactions of children vaccinated with chicken pox vaccine%儿童接种水痘疫苗的不良反应观察及护理体会

    Institute of Scientific and Technical Information of China (English)

    李晓琴

    2015-01-01

    objective: to investigate the children chickenpox vaccine adverse reactions and the nursing countermeasures. Methods: retrospectiveanalysis of 226 cases of children had chickenpox vaccine in our adverse reactions and the nursing measures. Results: all children within a few hours after inoculation, there are different degree of mild fever, swelling pain, mild skin rashes, mild chicken pox adverse reaction, nursing measures, reduce the adverse reaction. Conclusion: the adverse reactions of vaccinated children appear in the corresponding nursing measures, can effectively reduce the occurrence of adverse reactions, and improve the success rate of the vaccination is chickenpox vaccine ascending children's health.%目的:探讨儿童接种水痘疫苗的不良反应及护理对策.方法:回顾分析我院已经接种水痘疫苗的儿童226例的不良反应及护理措施.结果:所有儿童在接种结束后的几小时内,出现有不同程度上的轻微发热、局部红肿疼痛、轻微皮疹、轻度水痘不良反应,采取护理措施后,不良反应减少.结论:针对接种后的儿童出现的不良反应进行相应的护理措施,能够有效的减少不良反应的发生,提高接种是水痘疫苗的成功率,提升儿童的身体健康.

  8. Crossed beam reaction of the cyano radical, CN(X 2Σ+), with methylacetylene, CH3CCH (X 1A1): Observation of cyanopropyne, CH3CCCN (X 1A1), and cyanoallene, H2CCCHCN (X 1A')

    Science.gov (United States)

    Huang, L. C. L.; Balucani, N.; Lee, Y. T.; Kaiser, R. I.; Osamura, Y.

    1999-08-01

    The chemical dynamics to form cyanopropyne, CH3CCCN (X 1A1), and cyanoallene, H2CCCHCN (X 1A'), via the neutral-neutral reaction of the cyano radical, CN (X 2Σ+), with methylacetylene, CH3CCH (X 1A1), is investigated under single collision conditions in a crossed molecular beam experiment at a collision energy of 24.7 kJ mol-1. The laboratory angular distribution and time-of-flight spectra of the C4H3N products are recorded at m/e=65, 64, 63, and 62. The reaction of d3-methylacetylene, CD3CCH (X 1A1), with CN radicals yields reactive scattering signal at m/e=68 and m/e=67 demonstrating that two distinct H(D) atom loss channels are open. Forward-convolution fitting of the laboratory data reveal that the reaction dynamics are indirect and governed by an initial attack of the CN radical to the π electron density of the β carbon atom of the methylacetylene molecule to form a long lived CH3CCHCN collision complex. The latter decomposes via two channels, i.e., H atom loss from the CH3 group to yield cyanoallene, and H atom loss from the acetylenic carbon atom to form cyanopropyne. The explicit identification of the CN vs H exchange channel and two distinct product isomers cyanoallene and cyanopropyne strongly suggests the title reaction as a potential route to form these isomers in dark molecular clouds, the outflow of dying carbon stars, hot molecular cores, as well as the atmosphere of hydrocarbon rich planets and satellites such as the Saturnian moon Titan.

  9. Catalysis of Photochemical Reactions.

    Science.gov (United States)

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  10. Nuclear reactions in astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, M.; Rayet, M. (Universite Libre de Bruxelles (BE))

    1990-06-01

    At all times and at all astrophysical scales, nuclear reactions have played and continue to play a key role. This concerns the energetics as well as the production of nuclides (nucleosynthesis). After a brief review of the observed composition of various objects in the universe, and especially of the solar system, the basic ingredients that are required in order to build up models for the chemical evolution of galaxies are sketched. Special attention is paid to the evaluation of the stellar yields through an overview of the important burning episodes and nucleosynthetic processes that can develop in non-exploding or exploding stars. Emphasis is put on the remaining astrophysical and nuclear physics uncertainties that hamper a clear understanding of the observed characteristics, and especially compositions, of a large variety of astrophysical objects.

  11. On thermonuclear reaction rates

    OpenAIRE

    Hans J. Haubold; Mathai, Arak Mathai

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  12. Carbon-carbon cross-coupling reactions catalyzed by a two-coordinate nickel(II)-bis(amido) complex via observable Ni(I) , Ni(II) , and Ni(III) intermediates.

    Science.gov (United States)

    Lipschutz, Michael I; Tilley, T Don

    2014-07-01

    Recently, the development of more sustainable catalytic systems based on abundant first-row metals, especially nickel, for cross-coupling reactions has attracted significant interest. One of the key intermediates invoked in these reactions is a Ni(III) -alkyl species, but no such species that is part of a competent catalytic cycle has yet been isolated. Herein, we report a carbon-carbon cross-coupling system based on a two-coordinate Ni(II) -bis(amido) complex in which a Ni(III) -alkyl species can be isolated and fully characterized. This study details compelling experimental evidence of the role played by this Ni(III) -alkyl species as well as those of other key Ni(I) and Ni(II) intermediates. The catalytic cycle described herein is also one of the first examples of a two-coordinate complex that competently catalyzes an organic transformation, potentially leading to a new class of catalysts based on the unique ability of first-row transition metals to accommodate two-coordinate complexes.

  13. Potential reactivity of the andesitic rocks from Cabo de Gata (SE Spain); Reactividad potencial de las rocas andesiticas de Cabo de Gata (SE de Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, J.; Iglesia, A. la; Garcia Calleja, M. A.; Lopez-Ruiz, J.

    2010-07-01

    Andesitic rocks produce an alkali-silica reaction with the components of the interstitial phase of concrete. This reaction can be considered as belonging to the slow-kinetic type, since the incongruent dissolution of the rock-forming minerals leads to the late formation of siliceous calc-alkaline gel. As a conquence, the conventional mortar-bar method does not detect such reaction until 90 days later. (Author) 9 refs.

  14. Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

    Science.gov (United States)

    Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

    2016-01-01

    A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

  15. Low body weight and type of protease inhibitor predict discontinuation and treatment-limiting adverse drug reactions among HIV-infected patients starting a protease inhibitor regimen: consistent results from a randomized trial and an observational cohort

    DEFF Research Database (Denmark)

    Kirk, O; Gerstoft, J; Pedersen, C;

    2001-01-01

    therapy within less than 2 years. In both populations TLADR were the most common reason for discontinuation. The incidence of TLADR in RAS was: 8.5 (indinavir), 66.0 (ritonavir), 15.6 (saquinavir hard gel) per 100 person-years of follow-up (P ... risk factors for treatment discontinuation and TLADR in both groups. In OBC, the risk of developing TLADR increased by 12% per 5 kg lower body weight when starting the PI regimen [the relative hazard (RH) was 1.12 (95% confidence interval: 1.05-1.19) per 5 kg lighter], and starting ritonavir...... was associated with a three- to sixfold higher risk of TLADR relative to other PI regimens. Very similar results were documented in RAS [RH for body weight was 1.18 (1.07-1.29)]. CONCLUSIONS: Nearly half of the patients stopped treatment with the initial PI, most commonly as a result of adverse drug reactions...

  16. Practice Gaps: Drug Reactions.

    Science.gov (United States)

    Wolverton, Stephen E

    2016-07-01

    The term "drug reactions" is relevant to dermatology in three categories of reactions: cutaneous drug reactions without systemic features, cutaneous drug reactions with systemic features, and systemic drugs prescribed by the dermatologist with systematic adverse effects. This article uses examples from each of these categories to illustrate several important principles central to drug reaction diagnosis and management. The information presented will help clinicians attain the highest possible level of certainty before making clinical decisions. PMID:27363888

  17. Planar-transverse amplitude-phase pattern in nonelastic reactions

    International Nuclear Information System (INIS)

    The first evidence is presented that the phase pattern of the planar-transverse optimal reaction amplitudes found previously for elastic-scattering strong-interaction reactions also holds for nonelastic reactions. The pattern is observed in the reaction p+p→d+π in the energy range between 300 and 800 MeV

  18. Planar-transverse amplitude-phase pattern in nonelastic reactions

    Science.gov (United States)

    Arash, Firooz; Moravcsik, Michael J.; Goldstein, Gary R.; Bugg, David V.

    1989-01-01

    The first evidence is presented that the phase pattern of the planar-transverse optimal reaction amplitudes found previously for elastic-scattering strong-interaction reactions also holds for nonelastic reactions. The pattern is observed in the reaction p+p-->d+π in the energy range between 300 and 800 MeV.

  19. 阳性激发点推拿方案治疗足底筋膜炎临床观察%Clinical Observation of Treating Plantar Fasciitis through Positive Reaction Point Massage

    Institute of Scientific and Technical Information of China (English)

    杨扬; 赵雨; 吕建琴

    2012-01-01

    目的 探讨阳性激发点推拿治疗对足底筋膜炎的临床疗效.方法 对2011年3月-8月门诊确诊为足底筋膜炎的52例患者,采用随机方式分为治疗组和对照组各26例,治疗组采用阳性激发点推拿,对照组采用电针治疗.并对两组患者治疗5次后的即时疗效率、日本骨科学会(JOA)足底治疗疗效评分、每次治疗后的疼痛面谱量化评分、3个月随访疼痛复发率等疗效进行对照分析.结果 治疗组和对照组经连续治疗5次后,其JOA足底治疗疗效评分分别为(91.32±10.61)、(82.92±13.61)分,总有效率分别为96.15%、80.77%,差异均有统计学意义(P<0.05).疼痛面谱量化评分,治疗组在第一次治疗后较对照组改善明显,差异有统计学意义(P<0.05).3个月后随访疼痛复发情况,治疗组复发人数较对照组少,差异有统计学意义(P<0.05).结论 阳性激发点推拿治疗法对改善足底筋膜炎引发的足底疼痛、步行不适等症状优于电针治疗法,值得临床推广运用.%Objective To discuss the clinical effects of positive reaction point massage in treating plantar fasciitis. Methods Fifty-two patients diagnosed to have plantar fasciitis between March and August 2011 in our hospital were randomly divided into the treatment group and the control group with 26 patients in each. Patients in the treatment group were treated by positive reaction point massage, while those in the control group were treated by acupuncture. Then, the immediate effective rate after 5 times of treatment, Japanese Orthopedic Association (JOA) Scores, the assessment face scale (AFS) scores, and recurrences after 3 months were compared and analyzed between the two groups of patients. Results After 5 times of continuous treatment, JOA scores for patients in the treatment group and the control group were respectively 91.32 ± 10.61 and 82.92 ± 13.61, and the total effective rate were 96.15% and 80.77% for the two groups, which were

  20. Interface reactions in film materials

    Institute of Scientific and Technical Information of China (English)

    Fengwu Zhu; Zhonghai Zhai; Guanghua Yu

    2003-01-01

    Interface reaction (IR) is a frequently observed phenomenon in the study of advanced thin film materials. It is very important to study the reaction conditions at which IR happens and then to suppress or make use of it, the necessary conditions, including both thermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems, including oxide/silicon,oxide/metal, metal/metal, metal/semiconductor and semiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were also introduced.

  1. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  2. Common Reactions After Trauma

    Science.gov (United States)

    ... here Enter ZIP code here Common Reactions After Trauma Public This section is for Veterans, General Public, Family, & Friends Common Reactions After Trauma Available in Spanish: Reacciones Comunes Después de un ...

  3. Anaphylaxis-Like Reactions

    Science.gov (United States)

    ... be "primed" by previous exposure to cause anaphylaxis, anaphylactoid reactions can occur with no previous exposure at all. ... an X-ray. Although the mechanism of an anaphylactoid reaction is different, the treatment is the same as ...

  4. Microscale Thermite Reactions.

    Science.gov (United States)

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  5. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately

  6. Double Pion Production Reactions

    CERN Document Server

    Oset, E; Cano, F; Hernández, E; Kamalov, S S; Nacher, J C; Tejedor, J A G

    1999-01-01

    We report on reactions producing two pions induced by real and virtual photons or nucleons. The role of different resonances in these reactions is emphasized. Novel results on coherent two pion photoproduction in nuclei are also reported.

  7. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  8. Anaphylactoid reactions to paracetamol

    OpenAIRE

    Ayonrinde, O.; Saker, B.

    2000-01-01

    The toxic effects of paracetamol in overdose quantities are well recognised but the occurrence of anaphylactoid reactions to paracetamol is infrequently identified by consumers and health care professionals. Nevertheless adverse reactions to this drug, even in therapeutic doses, can have fatal or near fatal consequences. A case of an anaphylactoid reaction to paracetamol is described.


Keywords: paracetamol; anaphylaxis; allergy; hypersensitivity

  9. Reaction pathways of propene pyrolysis.

    Science.gov (United States)

    Qu, Yena; Su, Kehe; Wang, Xin; Liu, Yan; Zeng, Qingfeng; Cheng, Laifei; Zhang, Litong

    2010-05-01

    The gas-phase reaction pathways in preparing pyrolytic carbon with propene pyrolysis have been investigated in detail with a total number of 110 transition states and 50 intermediates. The structure of the species was determined with density functional theory at B3PW91/6-311G(d,p) level. The transition states and their linked intermediates were confirmed with frequency and the intrinsic reaction coordinates analyses. The elementary reactions were explored in the pathways of both direct and the radical attacking decompositions. The energy barriers and the reaction energies were determined with accurate model chemistry method at G3(MP2) level after an examination of the nondynamic electronic correlations. The heat capacities and entropies were obtained with statistical thermodynamics. The Gibbs free energies at 298.15 K for all the reaction steps were reported. Those at any temperature can be developed with classical thermodynamics by using the fitted (as a function of temperature) heat capacities. It was found that the most favorable paths are mainly in the radical attacking chain reactions. The chain was proposed with 26 reaction steps including two steps of the initialization of the chain to produce H and CH(3) radicals. For a typical temperature (1200 K) adopted in the experiments, the highest energy barriers were found in the production of C(3) to be 203.4 and 193.7 kJ/mol. The highest energy barriers for the production of C(2) and C were found 174.1 and 181.4 kJ/mol, respectively. These results are comparable with the most recent experimental observation of the apparent activation energy 201.9 +/- 0.6 or 137 +/- 25 kJ/mol. PMID:20082392

  10. Trimolecular reactions of uranium hexafluoride with water.

    Science.gov (United States)

    Lind, Maria C; Garrison, Stephen L; Becnel, James M

    2010-04-01

    The hydrolysis reaction of uranium hexafluoride (UF(6)) is a key step in the synthesis of uranium dioxide (UO(2)) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF(6) molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizable barrier of 78.2 kJ x mol(-1), indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO(2) product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF(6) molecules and one water molecule, and (2) the reaction of two water molecules with a single UF(6) molecule. The predicted reaction of two UF(6) molecules with one water molecule displays an interesting "fluorine-shuttle" mechanism, a significant energy barrier of 69.0 kJ x mol(-1) to the formation of UF(5)OH, and an enthalpy of reaction (DeltaH(298)) of +17.9 kJ x mol(-1). The reaction of a single UF(6) molecule with two water molecules displays a "proton-shuttle" mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ x mol(-1) and an exothermic enthalpy of reaction (DeltaH(298)) of -13.9 kJ x mol(-1). The exothermic nature of the overall UF(6) + 2H(2)O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging. PMID:20210345

  11. 膝髋关节置换术后抗凝药物不良反应的观察及护理对策%Nursing interventions and Observation on Anticoagulant Drug Adverse Reactions After Joint Replacement of Hip and Knee

    Institute of Scientific and Technical Information of China (English)

    郭冬梅

    2015-01-01

    目的:探索膝髋关节置换术后使用抗凝药物不良反应的观察及护理对策。方法选取我院的120例患者,分为观察组和对照组,每组各有60例患者,对照组采用常规护理,观察组采用优质护理。结果观察组的患者总不良反应发生率以及住院时间与住院费用优于对照组(P<0.05)。结论优质护理在膝髋关节置换术后使用抗凝药物不良反应中的护理效果确切。%Objective To explore nursing strategy and the anticoagulant drug adverse reactions after joint replacement of hip and knee.Methods 120 cases were divided into observation group and control group, each group with 60 cases, control group received conventional nursing, observation group received high quality nursing.Results The observation group of patients with total incidence of adverse reactions and the length of hospital stay and hospital costs significantly better than that of control group (P<0.05).Conclusion The effect of high quality nursing in drug adverse reactions after joint replacement of hip and knee is exact.

  12. Weber's Law in Autocatalytic Reaction Networks

    CERN Document Server

    Inoue, Masayo

    2011-01-01

    Biological responses often obey Weber's law, according to which the magnitude of the response depends only on the fold change in the external input. In this study, we demonstrate that a system involving a simple autocatalytic reaction shows such response when a chemical is slowly synthesized by the reaction from a faster influx process. We also show that an autocatalytic reaction process occurring in series or in parallel can obey Weber's law with an oscillatory adaptive response. Considering the simplicity and ubiquity of the autocatalytic process, our proposed mechanism is thought to be commonly observed in biological reactions.

  13. Observation of a Broad Structure at an Invariant Mass of 4.32 GeV/$c^2$ in the Reaction $e^+e^-\\to\\pi^+\\pi^-\\psi(2S)$ Measured at BaBar

    CERN Document Server

    Aubert, B; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, R; Allen, M T; Allison, J; Allmendinger, T; Altenburg, D D; Andreotti, M; Angelini, C; Anulli, F; Arnaud, N; Aston, D; Azzolini, V; Baak, M; Back, J J; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Barate, R; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Battaglia, M; Bauer, J M; Bechtle, P; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Benelli, G; Berger, N; Bernard, D; Berryhill, J W; Best, D S; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bhuyan, B; Bianchi, F; Biasini, M; Biesiada, J; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P C; Blount, N L; Bomben, M; Bondioli, M; Bonneaud, G R; Bosisio, L; Boutigny, D; Bowerman, D A; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Briand, H; Brown, C M; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Bugg, W; Bukin, A D; Bula, R; Burchat, P R; Burke, J P; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Capra, R; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Cenci, R; Chai, X; Chaisanguanthum, K S; Chao, M; Charles, E; Charles, M J; Chauveau, J; Chavez, C A; Chen, A; Chen, C; Chen, E; Chen, J C; Chen, S; Chen, X; Chen, X R; Cheng, B; Cheng, C H; Chia, Y M; Cibinetto, G; Clark, P J; Claus, R; Cochran, J; Coleman, J P; Contri, R; Convery, M R; Cossutti, F; Cottingham, W N; Couderc, F; Covarelli, R; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L; Cristinziani, M; Cunha, A; Curry, S; Côté, D; D'Orazio, A; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; De Nardo, Gallieno; De Sangro, R; De, N; Del Amo-Sánchez, P; Del Buono, L; Del Re, D; Della Ricca, G; Denig, A G; Di Lodovico, F; Di Marco, E; Dingfelder, J C; Dittongo, S; Dong, L; Dorfan, J; Druzhinin, V P; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Ebert, M; Eckhart, E A; Eckmann, R; Edgar, C L; Edwards, A J; Egede, U; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Eyges, V; Fabozzi, F; Faccini, R; Fang, F; Feltresi, E; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Flacco, C J; Flack, R L; Flächer, H U; Flood, K T; Ford, K E; Ford, W T; Forster, I J; Forti, F; Fortin, D; Foulkes, S D; Franek, B; Frey, R; Fritsch, M; Fry, J R; Fulsom, B G; Gabathuler, E; Gaidot, A; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gary, J W; Gaspero, M; Gatto, C; Gaz, A; George, K A; Gill, M S; Giorgi, M A; Gladney, L; Glanzman, T; Godang, R; Golubev, V B; Gowdy, S J; Gradl, W; Graham, M T; Graugès-Pous, E; Grenier, P; Gritsan, A V; Groot; Grosdidier, G; Groysman, Y; Hadavand, H K; Haire, M; Halyo, V; Hamano, K; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, A J; Hartfiel, B L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hill, E J; Hirschauer, J F; Hitlin, D G; Hollar, J J; Hong, T M; Honscheid, K; Hopkins, D A; Hrynóva, T; Hufnagel, D; Hulsbergen, W D; Hutchcroft, D E; Höcker, A; Igonkina, O; Innes, W R; Izen, J M; Jackson, P D; Jackson, P S; Jacobsen, R G; Jain, V; Jasper, H; Jawahery, A; Jessop, C P; John, M J J; Judd, D; Kadyk, J A; Kagan, H; Karyotakis, Yu; Kass, R; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Klose, V; Knecht, N S; Koch, H; Kolomensky, Yu G; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kreisel, A; Krishnamurthy, M; Kroeger, R; Kroseberg, J; Kukartsev, G; Kutter, P E; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lanceri, L; Lange, D J; Lankford, A J; Latham, T E; Latour, E; Lau, Y P; Lazzaro, A; Le Diberder, F R; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Lewandowski, B; Li Gioi, L; Li, S; Li, X; Lista, L; Liu, H; Lo Vetere, M; LoSecco, J M; Lockman, W S; Lombardo, V; Long, O; Lou, X C; Lu, M; Luitz, S; Lund, P; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lü, C; Lüth, V; MacFarlane, D B; Macri, M M; Mader, W F; Majewski, S A; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Marchiori, G; Margoni, M; Marks, J; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Mclachlin, S E; Meadows, B T; Mellado, B; Menges, W; Messner, R; Meyer, N T; Meyer, W T; Mihályi, A; Mir, L M; Mishra, K; Mohanty, G B; Mommsen, R K; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M; Muheim, F; Müller, D R; Nagel, M; Naisbit, M T; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nesom, G; Nicholson, H; Nikolich, M B; Nogowski, R; Nugent, I M; O'Grady, C P; Ocariz, J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Oyanguren, A; Ozcan, V E; Paar, H P; Pacetti, S; Palano, A; Palombo, F; Pan, B; Pan, Y; Panduro-Vazquez, W; Panetta, J; Paolucci, P; Pappagallo, M; Park, W; Passaggio, S; Patel, P M; Patrignani, C; Patteri, P; Payne, D J; Pelizaeus, M; Perazzo, A; Perl, M; Peruzzi, I M; Peters, K; Petersen, B A; Petrella, A; Petzold, A; Piatenko, T; Piccolo, D; Piccolo, M; Piemontese, L; Pierini, M; Piredda, G; Playfer, S; Poireau, V; Polci, F; Pompili, A; Porter, F C; Posocco, M; Prell, S; Prencipe, E; Prepost, R; Pripstein, M; Pruvot, S; Pulliam, T; Purohit, M V; Qi, N D; Rahatlou, S; Rahimi, A M; Rahmat, R; Rama, M; Ratcliff, B N; Raven, G; Ricciardi, S; Richman, J D; Ritchie, J L; Rizzo, G; Roat, C; Roberts, D A; Robertson, A I; Robertson, S H; Robutti, E; Rodier, S; Roe, N A; Ronan, M T; Roney, J M; Rong, G; Roodman, A; Roos, L; Rosenberg, E I; Rotondo, M; Roudeau, P; Rubin, A E; Ruddick, W O; Ryd, A; Röthel, W; Sacco, R; Saeed, M A; Safai-Tehrani, F; Saleem, M; Salnikov, A A; Salvatore, F; Samuel, A; Sanders, D A; Santroni, A; Saremi, S; Satpathy, A; Schalk, T; Schenk, S; Schilling, C J; Schindler, R H; Schofield, K C; Schott, G; Schröder, T; Schröder, H; Schubert, J; Schubert, K R; Schumm, B A; Schune, M H; Schwiening, J; Schwierz, R; Schwitters, R F; Sciacca, C; Sciolla, G; Seiden, A; Sekula, S J; Serednyakov, S I; Sharma, V; Shen, B C; Sherwood, D J; Simard, M; Simi, G; Simonetto, F; Sinev, N B; Skovpen, Y I; Smith, A J S; Smith, J G; Snoek, H L; Snyder, A; Sobie, R J; Soffer, A; Sokoloff, M D; Solodov, E P; Spaan, B; Spanier, S M; Spitznagel, M; Spradlin, P; Steinke, M; Stelzer, J; Stocchi, A; Stoker, D P; Stroili, R; Strom, D; Strube, J; Stugu, B; Stängle, H; Su, D; Sullivan, M K; Summers, D J; Sundermann, J E; Suzuki, K; Swain, S K; Taras, P; Taylor, F; Telnov, A V; Teodorescu, L; Ter-Antonian, R; Therin, G; Thiebaux, C; Thompson, J M; Tisserand, V; Todyshev, Y K; Toki, W H; Torrence, E; Tosi, S; Touramanis, C; Ulmer, K A; Uwer, U; Van Bakel, N; Vasseur, G; Vavra, J; Verderi, M; Viaud, F B; Vitale, L; Voci, C; Voena, C; Volk, A; Wagner, S R; Wagoner, D E; Waldi, R; Walker, D; Walsh, J J; Wang, K; Wang, P; Wang, W F; Wappler, F R; Watson, A T; Weaver, M; Weinstein, A J R; Wenzel, W A; Wilden, L; Williams, D C; Williams, J C; Wilson, F F; Wilson, J R; Wilson, M G; Wilson, R J; Winklmeier, F; Wisniewski, W J; Wittgen, M; Wong, Q K; Wormser, G; Wren, A C; Wright, D H; Wright, D M; Wu, J; Wu, S L; Xie, Y; Yamamoto, R K; Yarritu, A K; Ye, S; Yi, J I; Yi, K; Young, C C; Yu, Z; Yéche, C; Zain, S B; Zallo, A; Zeng, Q; Zghiche, A; Zhang, J; Zhang, L; Zhao, H W; Zhu, Y S; Ziegler, V; Zito, M; Çuhadar-Dönszelmann, T; al, et

    2006-01-01

    We measure the cross section for the process $e^+e^-\\to\\pi^+\\pi^-\\psi(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II $e^+e^-$ storage rings. The study is based on 298 fb$^{-1}$ of data recorded with the BaBar detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. This structure is not compatible with the Y(4260) previously reported by this experiment. A single resonance is adequate to describe the cross-section in the low-energy region ($<$5.7 GeV).

  14. A unified diabatic description for electron transfer reactions, isomerization reactions, proton transfer reactions, and aromaticity.

    Science.gov (United States)

    Reimers, Jeffrey R; McKemmish, Laura K; McKenzie, Ross H; Hush, Noel S

    2015-10-14

    While diabatic approaches are ubiquitous for the understanding of electron-transfer reactions and have been mooted as being of general relevance, alternate applications have not been able to unify the same wide range of observed spectroscopic and kinetic properties. The cause of this is identified as the fundamentally different orbital configurations involved: charge-transfer phenomena involve typically either 1 or 3 electrons in two orbitals whereas most reactions are typically closed shell. As a result, two vibrationally coupled electronic states depict charge-transfer scenarios whereas three coupled states arise for closed-shell reactions of non-degenerate molecules and seven states for the reactions implicated in the aromaticity of benzene. Previous diabatic treatments of closed-shell processes have considered only two arbitrarily chosen states as being critical, mapping these states to those for electron transfer. We show that such effective two-state diabatic models are feasible but involve renormalized electronic coupling and vibrational coupling parameters, with this renormalization being property dependent. With this caveat, diabatic models are shown to provide excellent descriptions of the spectroscopy and kinetics of the ammonia inversion reaction, proton transfer in N2H7(+), and aromaticity in benzene. This allows for the development of a single simple theory that can semi-quantitatively describe all of these chemical phenomena, as well as of course electron-transfer reactions. It forms a basis for understanding many technologically relevant aspects of chemical reactions, condensed-matter physics, chemical quantum entanglement, nanotechnology, and natural or artificial solar energy capture and conversion.

  15. Tumor Necrosis Factor (TNF-alpha) Treatment of Ankylosing Spondylitis Clinical Adverse Reactions Observed%肿瘤坏死因子拮抗剂(TNF-α)治疗强直性脊柱炎临床不良反应观察

    Institute of Scientific and Technical Information of China (English)

    徐刚

    2012-01-01

      Objective:To learn about the common and the rare adverse reactions taking place in the clinical treatment of ankylosing spondylitis with tumor necrosis factor (TNF) antagonist.Method:50 cases of patients were enrolled in this group receiving TNF antagonist (the product used in this group was Etanercept from Shanghai CP Guojian Pharmaceutical Co,Ltd) for treating ankylosing spondylitis.In addition,the incidence of adverse reactions and the common reverse reactions were observed.Result:Of the 50 patients received TNF antagonist for treating ankylosing spondylitis,first-dosage adverse reactions occurred in eight cases and medium or long-term adverse reactions occurred in 5 cases.Conclusion:The usage of biological agent in the treatment of ankylosing spondylitis is considered as a safe and efficacious approach,in which the occurrence and management of the adverse reactions should be concerned.%  目的:了解接受肿瘤坏死因子拮抗剂治疗强直性脊柱炎临床常见不良反应及少见不良反应。方法:本组选取了50例强直性脊柱炎患者接受肿瘤坏死因子拮抗剂(本组均选用上海中信科健公司产品益赛普)治疗,同时观察不良反应发生率及常见不良反应症状。结果:接受肿瘤坏死因子拮抗剂治疗的50例患者发生首次不良反应的有8例,中长期不良反应5例。结论:生物制剂治疗强直性脊柱炎是安全有效的,但应注意不良反应的发生及处置。

  16. Controlling chemical reactions of a single particle

    CERN Document Server

    Ratschbacher, Lothar; Sias, Carlo; Köhl, Michael

    2012-01-01

    The control of chemical reactions is a recurring theme in physics and chemistry. Traditionally, chemical reactions have been investigated by tuning thermodynamic parameters, such as temperature or pressure. More recently, physical methods such as laser or magnetic field control have emerged to provide completely new experimental possibilities, in particular in the realm of cold collisions. The control of reaction pathways is also a critical component to implement molecular quantum information processing. For these undertakings, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achi...

  17. Cosmetic tattoo pigment reaction

    OpenAIRE

    Greywal, Tanya; Cohen, Philip R

    2016-01-01

    BackgroundCutaneous reactions to tattoos are most commonly granulomatous or lichenoid. PurposeWe describe a woman who developed a lymphocytic reaction following a cosmetic tattoo procedure with black dye. The reaction occurred not only at the site of the tattoos (eyebrows and eyelash lines), but also in non-tattooed skin (bilateral malar cheeks). Methods and MaterialsWe reviewed PubMed for the following terms: cosmetic, dye, granuloma, granulomatous, lichenoid, lymphocytic, ...

  18. Anaphylactic reactions to cinoxacin.

    OpenAIRE

    Stricker, B H; Slagboom, G.; Demaeseneer, R.; Slootmaekers, V.; Thijs, I.; Olsson, S

    1988-01-01

    During 1981 to mid-1988 three cases of anaphylactic shock after treatment with the quinolone derivative cinoxacin were reviewed by the Netherlands Centre for Monitoring of Adverse Reactions to Drugs and 17 cases of an anaphylactic type of reaction notified to the World Health Organisation Collaborating Centre for International Drug Monitoring. In five out of six patients for whom data were available the reaction began shortly after taking a single capsule of a second or next course of treatme...

  19. Reaction kinetics of polybutylene terephthalate polycondensation reaction

    NARCIS (Netherlands)

    Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.

    2005-01-01

    The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl tereph

  20. Reactions at Solid Surfaces

    CERN Document Server

    Ertl, Gerhard

    2009-01-01

    Expanding on the ideas first presented in Gerhard Ertl's acclaimed Baker Lectures at Cornell University, Reactions at Solid Surfaces comprises an authoritative, self-contained, book-length introduction to surface reactions for both professional chemists and students alike. Outlining our present understanding of the fundamental processes underlying reactions at solid surfaces, the book provides the reader with a complete view of how chemistry works at surfaces, and how to understand and probe the dynamics of surface reactions. Comparing traditional surface probes with more modern ones, and brin

  1. Desosamine in multicomponent reactions

    NARCIS (Netherlands)

    Achatz, Sepp; Dömling, Alexander

    2006-01-01

    Desosamine occurring ubiquitously in natural products is introduced into isocyanide based multicomponent reaction chemistry. Corresponding products are of potential interest for the design of novel antibiotics. © 2006.

  2. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  3. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  4. Chemical reaction and separation method

    NARCIS (Netherlands)

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.

    2005-01-01

    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  5. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    OpenAIRE

    Kara, P; Csetényi, L; Borosnyói, A

    2014-01-01

    In several countries, waste glass causes environmental concerns as quantities stockpiled exceed recycling in the packaging stream. Being amorphous and having relatively high silicium and calcium contents, glass is pozzolanic or even cementitious, when finely ground. Reducing particle sizes typically to less than 100 µm may give control over the alkali-silica reaction in concrete, therefore making this material a possible substitute to Portland cement. Such use may moderate the problem of dump...

  6. The Permeability and Strength of Green High Performance Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHU Ping-hua; YANG Li-yuan; CHEN Hua-jian; JIANG Cang-ru

    2003-01-01

    The permeability,alkali-silica reaction,workability and strength of GHPC(green high performance concrete) were studied in this paper.The results show that GHPC has an excellent durability and the effects of mass ratio of flyash to high calcium slag,water-binder ratio,content of water reducer,and crushed coarse aggregate type on the workability and strength of GHPC were considerably evident.A new path for the concretes continuous development was put forward.

  7. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction

  8. 鼻咽癌同期放化疗中急性皮肤黏膜反应的临床观察及其相关因素分析%Clinical observation of acute skin and oral mucous membrane reactions in patients with nasopharyngeal carcinoma treated with concurrent radiochemotherapy and correlated factors

    Institute of Scientific and Technical Information of China (English)

    成灏; 吴慧; 卢晓旭; 徐靖

    2014-01-01

    目的 探讨鼻咽癌患者同期放化疗中急性皮肤及黏膜反应的影响因素,对主要相关因素进行分析.方法 对85例接受同期放化疗的鼻咽癌患者进行研究,观察并记录BMI、每周放疗剂量、口腔黏膜及颈部皮肤反应情况、血常规等15项临床指标及实验室指标,并进行单因素分析和多因素分析,筛选决定性影响因素.结果 与急性放射性口腔黏膜反应发生密切相关的危险因素,有吸烟史(OR=3.467,P<0.05)和原发灶GTV单次量>2.15 Gy(OR =3.393,P<0.05);与急性放射性皮肤反应发生密切相关的危险因素,有糖尿病史(OR=87.859,P<0.05),放疗前1周血红蛋白值> 130 g/L(OR=21.404,P<0.05).结论 对于同期放化疗的鼻咽癌患者,吸烟史和原发灶GTV单次量为急性放射性口腔黏膜反应的独立影响因素,糖尿病史和放疗前1周的血红蛋白值为急性放射性皮肤反应的独立影响因素.%Objective To observe the acute skin and mucous membrane reactions in patients treated with concurrent radiochemotherapy for nasopharyngeal carcinoma,and to analyze the influencing factors.Methods A total of 85 nasopharyngeal carcinoma cases treated with concurrent radiochemotherapy were enrolled in the study.Fifteen clinical and laboratory indexes,including BMI,radiation dose,degree of acute oral mucous and skin reactions and blood routine test were observed weekly.Univariate and multivariate regression analysis were performed to assess the factors,and screen the independent factors.Results Multiple-factor analysis showed that the risk factors cloesly related with acute radioactive oral mucosa reactions were smoking history(OR =3.467,P < 0.05),single-dose of gross tumor volume (GTV) >2.15 Gy(OR =3.393,P < 0.05),while those with acute radiation skin reactions were diabetes history(OR =87.859,P < 0.05) and hemoglobin values 1 week before radiotherapy > 130 g/L (OR =21.404,P < 0.05).Conclusions In the patients treated

  9. Biochemical reaction engineering for redox reactions.

    Science.gov (United States)

    Wandrey, Christian

    2004-01-01

    Redox reactions are still a challenge for biochemical engineers. A personal view for the development of this field is given. Cofactor regeneration was an obstacle for quite some time. The first technical breakthrough was achieved with the system formate/formate dehydrogenase for the regeneration of NADH2. In cases where the same enzyme could be used for chiral reduction as well as for cofactor regeneration, isopropanol as a hydrogen source proved to be beneficial. The coproduct (acetone) can be removed by pervaporation. Whole-cell reductions (often yeast reductions) can also be used. By proper biochemical reaction engineering, it is possible to apply these systems in a continuous way. By cloning a formate dehydrogenase and an oxidoreductase "designer bug" can be obtained where formate is used instead of glucose as the hydrogen source. Complex sequences of redox reactions can be established by pathway engineering with a focus on gene overexpression or with a focus on establishing non-natural pathways. The success of pathway engineering can be controlled by measuring cytosolic metabolite concentrations. The optimal exploitation of such systems calls for the integrated cooperation of classical and molecular biochemical engineering.

  10. Nuclear Reactions from Lattice QCD

    CERN Document Server

    Briceño, Raúl A; Luu, Thomas C

    2014-01-01

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path ...

  11. Observables, Disassembled

    CERN Document Server

    Roberts, Bryan W

    2016-01-01

    This paper argues that non-self-adjoint operators can be observables. There are only four ways for this to occur: non-self-adjoint observables can either be normal operators, or be symmetric, or have a real spectrum, or have none of these three properties. I explore each of these four classes of observables, arguing that the class of normal operators provides an equivalent formulation of quantum theory, whereas the other classes considerably extend it.

  12. Finkelstein Reaction in Functionalized Crown-ether Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Xiao Hua WANG; Han Zhi WANG; Hui LIU; Yuan KOU

    2006-01-01

    Functional crown-ether ionic liquids were used as catalytic green solvents of Finkelstein reaction of 1-bromooctane and iodide. The rate and yield of the reaction were obvious improved compared with that using crown ether in water. No free crown ether loss was observed after reaction.

  13. In situ AFM Observations of Li-Oxygen Electrochemical Reactions

    OpenAIRE

    Katharajan, Hariharan; Virwani, Kumar; Erpelding, A. David; Garcia, Jeannette M.

    2016-01-01

    The morphologies of crystalline lithium peroxide (Li2O2) discharge products in Li-O2 batteries have been shown to exhibit a dependency on subtle variations within the battery cell-operating environment including exposure to ambient air, moisture, or additives. As a result, imaging battery discharge products in real time under carefully controlled environmental conditions is a challenging obstacle for complete mechanistic understanding of Li2O2 growth and deposition during discharge in metal-a...

  14. Isovector spin observables in nuclear charge reactions at LAMPF

    International Nuclear Information System (INIS)

    LAMPF has undertaken a major development program to upgrade facilities for nuclear charge-exchange studies at intermediate energies. The major components of this upgrade are a medium-resolution spectrometer and neutron time-of-flight system for good resolution (δ E < 1 MeV) charge-exchange perograms in (n,p) and (p,n) respectively. Major emphasis is placed on polarization phenomena using polarized beams and analyzing the polarization of the outgoing particle

  15. Hypersensitivity reactions to corticosteroids.

    Science.gov (United States)

    Vatti, Rani R; Ali, Fatima; Teuber, Suzanne; Chang, Christopher; Gershwin, M Eric

    2014-08-01

    Hypersensitivity reactions to corticosteroids (CS) are rare in the general population, but they are not uncommon in high-risk groups such as patients who receive repeated doses of CS. Hypersensitivity reactions to steroids are broadly divided into two categories: immediate reactions, typically occurring within 1 h of drug administration, and non-immediate reactions, which manifest more than an hour after drug administration. The latter group is more common. We reviewed the literature using the search terms "hypersensitivity to steroids, adverse effects of steroids, steroid allergy, allergic contact dermatitis, corticosteroid side effects, and type I hypersensitivity" to identify studies or clinical reports of steroid hypersensitivity. We discuss the prevalence, mechanism, presentation, evaluation, and therapeutic options in corticosteroid hypersensitivity reactions. There is a paucity of literature on corticosteroid allergy, with most reports being case reports. Most reports involve non-systemic application of corticosteroids. Steroid hypersensitivity has been associated with type I IgE-mediated allergy including anaphylaxis. The overall prevalence of type I steroid hypersensitivity is estimated to be 0.3-0.5%. Allergic contact dermatitis (ACD) is the most commonly reported non-immediate hypersensitivity reaction and usually follows topical CS application. Atopic dermatitis and stasis dermatitis of the lower extremities are risk factors for the development of ACD from topical CS. Patients can also develop hypersensitivity reactions to nasal, inhaled, oral, and parenteral CS. A close and detailed evaluation is required for the clinician to confirm the presence of a true hypersensitivity reaction to the suspected drug and choose the safest alternative. Choosing an alternative CS is not only paramount to the patient's safety but also ameliorates the worry of developing an allergic, and potentially fatal, steroid hypersensitivity reaction. This evaluation becomes

  16. Electron transfer reactions

    CERN Document Server

    Cannon, R D

    2013-01-01

    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  17. The Reaction Wheel Pendulum

    CERN Document Server

    Block, Daniel J; Spong, Mark W

    2007-01-01

    This monograph describes the Reaction Wheel Pendulum, the newest inverted-pendulum-like device for control education and research. We discuss the history and background of the reaction wheel pendulum and other similar experimental devices. We develop mathematical models of the reaction wheel pendulum in depth, including linear and nonlinear models, and models of the sensors and actuators that are used for feedback control. We treat various aspects of the control problem, from linear control of themotor, to stabilization of the pendulum about an equilibrium configuration using linear control, t

  18. Modification of the tuberculin reaction by levan.

    Science.gov (United States)

    Shezen, E.; Leibovici, J.; Wolman, M.

    1978-01-01

    High molecular levan (polyfructoside) inhibits the skin tuberculin reaction in guinea pigs as judged by the degree of induration and erythema. The effect is dose-dependent. No effect on cellular infiltration was observed in histological studies. The lymph nodes of levan-treated animals were smaller and exhibited a much milder granulomatous reaction than those of non-treated animals. Images Fig. 2 Fig. 3 PMID:718799

  19. Catalytic Friedel-Crafts reaction of aminocyclopropanes.

    Science.gov (United States)

    de Nanteuil, Florian; Loup, Joachim; Waser, Jérôme

    2013-07-19

    A Lewis acid catalyzed Friedel-Crafts reaction between donor-acceptor aminocyclopropanes and indoles and other electron-rich aromatic compounds is reported. Indole alkylation at the C3 position was generally obtained for a broad range of functional groups and substitution patterns. In the case of C3-substituted indoles, C2 alkylation was observed. The reaction gives a rapid access to gamma amino acid derivatives present in numerous bioactive molecules. PMID:23815365

  20. Fractional diffusion equations coupled by reaction terms

    Science.gov (United States)

    Lenzi, E. K.; Menechini Neto, R.; Tateishi, A. A.; Lenzi, M. K.; Ribeiro, H. V.

    2016-09-01

    We investigate the behavior for a set of fractional reaction-diffusion equations that extend the usual ones by the presence of spatial fractional derivatives of distributed order in the diffusive term. These equations are coupled via the reaction terms which may represent reversible or irreversible processes. For these equations, we find exact solutions and show that the spreading of the distributions is asymptotically governed by the same the long-tailed distribution. Furthermore, we observe that the coupling introduced by reaction terms creates an interplay between different diffusive regimes leading us to a rich class of behaviors related to anomalous diffusion.

  1. Competitive Reactions to Advertising and Promotion Attacks

    OpenAIRE

    Jan-Benedict E. M. Steenkamp; Vincent R. Nijs; Dominique M. Hanssens; Dekimpe, Marnik G.

    2005-01-01

    How do competitors react to each other's price-promotion and advertising attacks? What are the reasons for the observed reaction behavior? We answer these questions by performing a large-scale empirical study on the short-run and long-run reactions to promotion and advertising shocks in over 400 consumer product categories over a four-year time span. Our results clearly show that the most predominant form of competitive response is passive in nature. When a reaction does occur, it is usually ...

  2. Nucleon induced reactions

    International Nuclear Information System (INIS)

    The collection contains full texts of 37 contributions; all fall within the INIS Subject Scope. The topics treated include some unsolved problems of nuclear reactions and relevant problems of nuclear structure at low and intermediate energies. (Z.S.)

  3. Reaction Qualifications Revisited

    DEFF Research Database (Denmark)

    Lippert-Rasmussen, Kasper

    2009-01-01

      When, in a competitive sphere, people are selected on the basis of qualifications only, their chances of acquiring positions of advantage may seem to depend entirely upon their abilities, not discriminatory bias. However, if reaction qualifications - i.e. characteristics which contribute...... to a person's effectiveness by causing a favourable reaction in customers, co-workers etc. (for short: recipients) - are involved, this assumption is false. Building on work by Wertheimer, Mason, and Miller, this paper proposes an account of the reaction qualifications that count, from the point of view...... preferences, recipients should not respond to the applicant actually hired on the basis of their (the recipients') racial preferences. My account decomposes the meritocratic ideal into four separate norms, one of which applies to recipients rather than to selectors. Finally, it defends the view that reaction...

  4. Autocatalysis in reaction networks.

    Science.gov (United States)

    Deshpande, Abhishek; Gopalkrishnan, Manoj

    2014-10-01

    The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is that if all reactions are reversible in a weak sense, then no species can go extinct. A notion that has been found useful in thinking about persistence is that of "critical siphon." We explore the combinatorics of critical siphons, with a view toward the persistence conjecture. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: Every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and nonautocatalytic weakly reversible networks are persistent. Our results clarify that the difficulties in proving the persistence conjecture are essentially due to competition between drainable and self-replicable siphons.

  5. Chemisorption And Precipitation Reactions

    Science.gov (United States)

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  6. Ofloxacin induced hypersensitivity reaction

    Directory of Open Access Journals (Sweden)

    Hari Babu Ramineni

    2015-01-01

    Full Text Available Ofloxacin is a commonly used antimicrobial agent to combat various infections. The adverse profile of quinolones includes gastrointestinal symptoms, which are the most frequent, neuropsychiatric symptoms, hematologic abnormalities are less common. We report a rare case of ofloxacin induced hypersensitivity reaction in a 57 year old female patient with complaints of rashes over the axilla, upper limb and back, abdomen, thorax associated with exfoliation of skin all over the axilla associated with severe itching. Based on history and clinical examination patient was diagnosed as ofloxacin induced hypersensitivity reaction and was successfully treated with antihistamines and corticosteroids. Pharmacovigilance should be a part of patient care in order to reduce occurrence of adverse drug reaction and also encourage practitioners in reporting so as to gather more and more data regarding adverse drug reactions. [Int J Res Med Sci 2015; 3(1.000: 349-351

  7. Allergic reactions in anaesthesia

    DEFF Research Database (Denmark)

    Krøigaard, M; Garvey, L H; Menné, T;

    2005-01-01

    BACKGROUND: The aim of this retrospective survey of possible allergic reactions during anaesthesia was to investigate whether the cause suspected by anaesthetists involved corresponded with the cause found on subsequent investigation in the Danish Anaesthesia Allergy Centre (DAAC). METHODS: Case...... notes and anaesthetic charts from 111 reactions in 107 patients investigated in the DAAC were scrutinized for either suspicions of or warnings against specific substances stated to be the cause of the supposed allergic reaction. RESULTS: In 67 cases, one or more substances were suspected. In 49...... match, the right substance being suspected, but investigations showed an additional allergen or several substances, including the right substance being suspected. CONCLUSIONS: An informed guess is not a reliable way of determining the cause of a supposed allergic reaction during anaesthesia and may put...

  8. Clinical Observation of Diphenhydramine Combined with Prednisone in the Prevention of Iodine-containing Contrast Agent Allergic Reactions%苯海拉明联合泼尼松预防碘造影剂过敏反应的临床观察

    Institute of Scientific and Technical Information of China (English)

    胡立禄; 高全清; 刘振良

    2016-01-01

    OBJECTIVE:To observe the success rate and safety of diphenhydramine combined with prednisone in the preven-tion of iodine-containing contrast agent allergic reactions. METHODS:1 day before surgery,42 patients with positive iodine aller-gy test was given 40 mg Prednisone tablet,orally,3 times a day,50 mg diphenhydramine was given by intramuscular injection and 1 ml iodine contrast by intravenous injection(allergy test performed again)1 h before surgery. After all patients used iodine con-trast in 15 min,vascular interventional treatment was conducted if there was no bronchospasm,angioedema,leather ball sample itchy rash,hypotension,itching and other allergic reactions. Prevention success rate were observed,and the incidence of adverse re-actions was recorded. RESULTS:Prevention success rate was 90.48%,the incidence of adverse reactions was 7.14%,and it self-improved after stopping drugs. CONCLUSIONS:Diphenhydramine combined with prednisone has high success rate in the pre-vention of iodine-containing contrast agent allergic reactions,with good safety.%目的:观察苯海拉明联合泼尼松预防碘造影剂过敏反应的成功率和安全性。方法:42例碘过敏试验呈阳性患者于术前1 d给予泼尼松片40 mg,口服,每日3次,术前1 h给予苯海拉明50 mg,肌内注射,并同时静脉注射碘造影剂1 ml(再次进行过敏试验)。所有患者使用碘造影剂15 min后若不存在支气管痉挛、血管性水肿、皮团样皮疹、低血压、瘙痒等过敏反应,方可行血管介入治疗。观察42例患者预防成功率及不良反应发生情况。结果:预防成功率为90.48%;不良反应发生率为7.14%,经停药后症状均自行好转。结论:苯海拉明联合泼尼松预防碘造影剂过敏反应具有较高的成功率,安全性较好。

  9. Adverse reactions to cosmetics

    OpenAIRE

    Dogra A; Minocha Y; Kaur S

    2003-01-01

    Adverse reaction to cosmetics constitute a small but significant number of cases of contact dermatitis with varied appearances. These can present as contact allergic dermatitis, photodermatitis, contact irritant dermatitis, contact urticaria, hypopigmentation, hyperpigmentotion or depigmentation, hair and nail breakage. Fifty patients were included for the study to assess the role of commonly used cosmetics in causing adverse reactions. It was found that hair dyes, lipsticks and surprisingly ...

  10. EXERCISE AND REACTION TIMES

    OpenAIRE

    Varun; Neeraj; Ushadhar; Yogesh; Rinku

    2015-01-01

    OBJECTIVES: Physical exercise provides multiple benefits to an individual. It is known that exercising regularly can prevent coronary heart disease, hypertension and obesity and improve flexibility. The effect of exercise on visual reaction time needs to be studied, a s the existing data on the benefit of aerobic exercise on psychomotor functions is insufficient. MATERIALS AND METHODS: Online Visual reaction time is measured before and after exercise. Subjects were ...

  11. Oxygen evolution reaction catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  12. Meson production in + reactions

    Indian Academy of Sciences (India)

    H Machner; M Betigeri; J Bojowald; A Budzanowski; A Chatterjee; J Ernst; L Freindl; D Frekers; W Garske; K Grewer; A Hamacher; J Ilieva; L Jarczyk; K Kilian; S Kliczewski; W Klimala; D Kolev; T Kutsarova; J Lieb; H Machner; A Magiera; H Nann; L Pentchev; H S Plendl; D Protić; B Razen; P Von Rossen; B J Roy; R Siudak; J Smyrski; R V Srikantiah; A Strzałkowski; R Tsenov; K Zwoll

    2001-08-01

    Total and differential cross sections for the reactions $p+d → 3He + 0 with = ; and + → 3H + + were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward–backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied.

  13. Observing Insects.

    Science.gov (United States)

    Arbel, Ilil

    1991-01-01

    Describes how to observe and study the fascinating world of insects in public parks, backyards, and gardens. Discusses the activities and habits of several common insects. Includes addresses for sources of beneficial insects, seeds, and plants. (nine references) (JJK)

  14. Hydrogen tunneling in enzyme reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Y.; Murray, C.J.; Klinman, J.P.

    1989-03-10

    Primary and secondary protium-to-tritium (H/T) and deuterium-to-tritium (D/T) kinetic isotope effects for the catalytic oxidation of benzyl alcohol to benzaldehyde by yeast alcohol dehydrogenase (YADH) at 25 degrees Celsius have been determined. Previous studies showed that this reaction is nearly or fully rate limited by the hydrogen-transfer step. Semiclassical mass considerations that do not include tunneling effects would predict that kH/kT = (kD/kT)3.26, where kH, kD, and kT are the rate constants for the reaction of protium, deuterium, and tritium derivatives, respectively. Significant deviations from this relation have now been observed for both primary and especially secondary effects, such that experimental H/T ratios are much greater than those calculated from the above expression. These deviations also hold in the temperature range from 0 to 40 degrees Celsius. Such deviations were previously predicted to result from a reaction coordinate containing a significant contribution from hydrogen tunneling.

  15. Hydrogen Tunneling in Enzyme Reactions

    Science.gov (United States)

    Cha, Yuan; Murray, Christopher J.; Klinman, Judith P.

    1989-03-01

    Primary and secondary protium-to-tritium (H/T) and deuterium-to-tritium (D/T) kinetic isotope effects for the catalytic oxidation of benzyl alcohol to benzaldehyde by yeast alcohol dehydrogenase (YADH) at 25 degrees Celsius have been determined. Previous studies showed that this reaction is nearly or fully rate limited by the hydrogen-transfer step. Semiclassical mass considerations that do not include tunneling effects would predict that kH/kT = (kD/kT)3.26, where kH, kD, and kT are the rate constants for the reaction of protium, deuterium, and tritium derivatives, respectively. Significant deviations from this relation have now been observed for both primary and especially secondary effects, such that experimental H/T ratios are much greater than those calculated from the above expression. These deviations also hold in the temperature range from 0 to 40 degrees Celsius. Such deviations were previously predicted to result from a reaction coordinate containing a significant contribution from hydrogen tunneling.

  16. Reaction Selectivity in Heterogeneous Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, Gabor A.; Kliewer, Christopher J.

    2009-02-02

    The understanding of selectivity in heterogeneous catalysis is of paramount importance to our society today. In this review we outline the current state of the art in research on selectivity in heterogeneous catalysis. Current in-situ surface science techniques have revealed several important features of catalytic selectivity. Sum frequency generation vibrational spectroscopy has shown us the importance of understanding the reaction intermediates and mechanism of a heterogeneous reaction, and can readily yield information as to the effect of temperature, pressure, catalyst geometry, surface promoters, and catalyst composition on the reaction mechanism. DFT calculations are quickly approaching the ability to assist in the interpretation of observed surface spectra, thereby making surface spectroscopy an even more powerful tool. HP-STM has revealed three vitally important parameters in heterogeneous selectivity: adsorbate mobility, catalyst mobility, and selective site-blocking. The development of size controlled nanoparticles from 0.8 to 10 nm, of controlled shape, and of controlled bimetallic composition has revealed several important variables for catalytic selectivity. Lastly, DFT calculations may be paving the way to guiding the composition choice for multi-metallic heterogeneous catalysis for the intelligent design of catalysts incorporating the many factors of selectivity we have learned.

  17. Observational astrophysics

    CERN Document Server

    Smith, Robert C

    1995-01-01

    Combining a critical account of observational methods (telescopes and instrumentation) with a lucid description of the Universe, including stars, galaxies and cosmology, Smith provides a comprehensive introduction to the whole of modern astrophysics beyond the solar system. The first half describes the techniques used by astronomers to observe the Universe: optical telescopes and instruments are discussed in detail, but observations at all wavelengths are covered, from radio to gamma-rays. After a short interlude describing the appearance of the sky at all wavelengths, the role of positional astronomy is highlighted. In the second half, a clear description is given of the contents of the Universe, including accounts of stellar evolution and cosmological models. Fully illustrated throughout, with exercises given in each chapter, this textbook provides a thorough introduction to astrophysics for all physics undergraduates, and a valuable background for physics graduates turning to research in astronomy.

  18. Satellite observations

    Science.gov (United States)

    1984-05-01

    In 1982 and 1983, six scientific satellites were operated successfully. Two of them, JIKIKEN and ISS-b, performed observations of the Earth's plasma environment. HINOTORI, the solar maximum satellite, observed a number of solar flares. HAKUCHO and newly launched TENMA conducted various observations of cosmic X-ray sources. HIMAWARI-2 is a meteorological satellite but its payload includes a solar particle monitor. EXOS-C was successfully launched in February, 1983, and participants in the MAP (Middle Atmosphere Program). Following these missions, the PLANET-A project comprising two missions, MS-T5 and PLANET-A, is under preparation for the participation in the international cooperative exploration of Comet P/Halley. The third X-ray astronomy satellite ASTRO-C is currently scheduled for 1987 launch.

  19. Observational $\\Delta\

    CERN Document Server

    Hernández, Antonio García; Monteiro, Mário J P F G; Suárez, Juan Carlos; Reese, Daniel R; Pascual-Granado, Javier; Garrido, Rafael

    2015-01-01

    Delta Scuti ($\\delta$ Sct) stars are intermediate-mass pulsators, whose intrinsic oscillations have been studied for decades. However, modelling their pulsations remains a real theoretical challenge, thereby even hampering the precise determination of global stellar parameters. In this work, we used space photometry observations of eclipsing binaries with a $\\delta$ Sct component to obtain reliable physical parameters and oscillation frequencies. Using that information, we derived an observational scaling relation between the stellar mean density and a frequency pattern in the oscillation spectrum. This pattern is analogous to the solar-like large separation but in the low order regime. We also show that this relation is independent of the rotation rate. These findings open the possibility of accurately characterizing this type of pulsator and validate the frequency pattern as a new observable for $\\delta$ Sct stars.

  20. Clinical Observation of the Effect of Thermal Insulation on the Intraopera-tive Stress Reaction of 68 Patients in the Operating Room%保温护理对68例手术室患者术中应激影响的临床观察

    Institute of Scientific and Technical Information of China (English)

    张瑾

    2015-01-01

    Objective To observe the clinical effect of thermal insulation on the intraoperative stress reaction of patients in the op-erating room. Methods 136 cases with surgery admitted in the Department of Surgery of our hospital from May 2012 to May 2014 were randomly divided into the control group(n=68) and the observation group(n=68), treated by the conventional nursing, thermal insulation, respectively. And the physiological stress response was compared between the two groups. Results The physiological stress response decreased significantly in both groups after surgery compared with before surgery, and that decreased more obvious-ly in the observation group than in the control group (P<0.05). The level of physiological indexes lowered significantly in both groups after surgery compared with before surgery, and that lowered more obviously in the observation group than in the control group(P<0.05). The scores of patients' satisfaction with therapeutic effect, operation, attitude, environment and propaganda and ed-ucation were much better in the observation group than those in the control group(P<0.05). The level of physiological indexes low-ered significantly in both groups after surgery compared with before surgery, and that lowered more obviously in the observation group than in the control group(P<0.05). The scores of level of patients' satisfaction with therapeutic effect, operation, attitude, en-vironment and propaganda and education were much higher in the observation group than those in the control group (P<0.05). Conclusion Thermal insulation can significantly improve the stress reaction in patients in the operating room, enhance the quality of nursing, and make the patients recover quickly with good clinical application value.%目的:探讨保温护理对手术室患者术中应激影响的临床效果。方法整群选取2012年5月-2014年5月在该院外科收治的手术的136例患者随机分为对照组(n=68,予以常规护理)和观察组(n=68,

  1. Immediate reaction to clarithromycin.

    Science.gov (United States)

    Gangemi, S; Ricciardi, L; Fedele, R; Isola, S; Purello-D'Ambrosio, F

    2001-01-01

    We present the case of bronchospastic reaction to clarithromycin had during a drug challenge test. Personal allergic history was negative for respiratory allergies and positive for adverse drug reactions to general and regional anesthesia and to ceftriaxone. After the administration of 1/4 of therapeutic dose of clarithromycin the patient showed dyspnea, cough and bronchospasm in all the lung fields. The positivity of the test was confirmed by the negativity to the administration of placebo. The quickness and the clinical characteristic of the adverse reaction suggest a pathogenic mechanism of immediate-type hypersensitivity. On reviewing the literature we have found no reports of bronchospastic reaction to clarithromycin. Macrolides are a class of antibiotics mainly used in the last years in place of beta-lactams because of a broad spectrum of action and a low allergic power. In fact, there are few reports on allergic reactions to these molecules. Clarithromycin is one of the latest macrolides, characterised by the presence of a 14-carbon-atom lactone ring as erythromycin, active on a wide spectrum of pathogens.

  2. In situ observation of surface reactions with synchrotron radiation induced semiconductor processes by infrared reflection absorption spectroscopy using buried metal layer substrates; Umekomi kinzokuso kiban wo mochiita sekigai hansha kyushu supekutoruho ni yoru hoshako reiki handotai process hanno no sonoba kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshigoe, A.; Hirano, S. [The Graduate University for Advanced Studies, Yokohama (Japan); Mase, K.; Urisu, T. [Institute for Molecular Science, Aichi (Japan)

    1996-11-20

    It is known that infrared reflection absorption spectroscopy (IRAS) on semiconductor or insulator surfaces becomes practicable by using buried metal layer (BML) substrates, in which the metal thin film is buried order semiconductor or insulator films. In this work, IRAS has been measured for Langmuir-Blodgett films deposited on the BML substrate with SiO2/Al/Si(100) structure and the observed spectrum intensity has been quantitatively compared with the calculation assuming the ideal multilayer structure for the BML substrate. The BML-IRAS using CoSi2 has been adopted to the detection of SiHn on the Si (100) substrate during synchrotron radiation (SR) stimulated Si2H6 gas source molecular beam epitaxy. It has been found that SiH2 and SiH3 on the Si (100) surface are easily decomposed by SR, but SiH can`t be decomposed. From these experiments, it has been concluded that the BML-IRAS is an useful in situ observation technique for the photo-stimulated surface reactions. 26 refs., 9 figs.

  3. Marketing Mix Reactions to Entry

    OpenAIRE

    Robinson, William T.

    1988-01-01

    Initial product, distribution, marketing expenditure, and price reactions by incumbents are examined for 115 entrants into oligopolistic markets. The most common reaction pattern is either no reaction or only a single reaction. It is very unusual for entrants to face reactions across the entire marketing mix. Reactions in the first two years after entry are explained as a function of the entrant's strategy, incumbent characteristics, and industry characteristics. The explanation provides insi...

  4. Introduction to chemical reaction engineering

    International Nuclear Information System (INIS)

    This deals with chemical reaction engineering with thirteen chapters. The contents of this book are introduction on reaction engineering, chemical kinetics, thermodynamics and chemical reaction, abnormal reactor, non-isothermal reactor, nonideal reactor, catalysis in nonuniform system, diffusion and reaction in porosity catalyst, design catalyst heterogeneous reactor in solid bed, a high molecule polymerization, bio reaction engineering, reaction engineering in material process, control multi-variable reactor process using digital computer.

  5. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  6. Adverse reactions to cosmetics

    Directory of Open Access Journals (Sweden)

    Dogra A

    2003-03-01

    Full Text Available Adverse reaction to cosmetics constitute a small but significant number of cases of contact dermatitis with varied appearances. These can present as contact allergic dermatitis, photodermatitis, contact irritant dermatitis, contact urticaria, hypopigmentation, hyperpigmentotion or depigmentation, hair and nail breakage. Fifty patients were included for the study to assess the role of commonly used cosmetics in causing adverse reactions. It was found that hair dyes, lipsticks and surprisingly shaving creams caused more reaction as compared to other cosmetics. Overall incidence of contact allergic dermatitis seen was 3.3% with patients own cosmetics. Patch testing was also done with the basic ingredients and showed positive results in few cases where casual link could be established. It is recommended that labeling of the cosmetics should be done to help the dermatologists and the patients to identify the causative allergen in cosmetic preparation.

  7. Inflammatory reaction in chondroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Yamamura, Sigeki [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sato, Keiji [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sugiura, Hideshi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Iwata, Hisashi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan)

    1996-05-01

    The objective of this study was to evaluate the inflammatory reaction accompanying chondroblastoma and to define the value of the finding in clinical practice. We reviewed the clinical, radiographic, and magnetic resonance (MR) findings in six patients with histologically proven chondroblastoma. In all cases, MR imaging showered marrow and soft tissue edema. In four of six cases, periosteal reaction related to intra-osseous edema was more clearly demonstrated on MR imaging than on radiographs. Follow-up MR studies after surgery were available in three patients and all showed disappearance of inflammatory responses such as marrow and soft tissue edema, and reactive synovitis. We propose that these inflammatory reactions of chondroblastomas are inportant signs for detecting residual tumor in recurrences after surgery, as well as for making a precise diagnosis. The MR changes may also be valuable in demonstrating eradication of the tumor. (orig./MG)

  8. Flare Observations

    Directory of Open Access Journals (Sweden)

    Benz Arnold O.

    2008-02-01

    Full Text Available Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting reconnection of magnetic field lines as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s lower ionosphere. While flare scenarios have slowly converged over the past decades, every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  9. Minisatellite Attitude Guidance Using Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Ion STROE

    2015-06-01

    Full Text Available In a previous paper [2], the active torques needed for the minisatellite attitude guidance from one fixed attitude posture to another fixed attitude posture were determined using an inverse dynamics method. But when considering reaction/momentum wheels, instead of this active torques computation, the purpose is to compute the angular velocities of the three reaction wheels which ensure the minisatellite to rotate from the initial to the final attitude. This paper presents this computation of reaction wheels angular velocities using a similar inverse dynamics method based on inverting Euler’s equations of motion for a rigid body with one fixed point, written in the framework of the x-y-z sequence of rotations parameterization. For the particular case A=B not equal C of an axisymmetric minisatellite, the two computations are compared: the active torques computation versus the computation of reaction wheels angular velocities ̇x , ̇y and ̇z. An interesting observation comes out from this numerical study: if the three reaction wheels are identical (with Iw the moment of inertia of one reaction wheel with respect to its central axis, then the evolutions in time of the products between Iw and the derivatives of the reaction wheels angular velocities, i.e. ̇ , ̇ and ̇ remain the same and do not depend on the moment of inertia Iw.

  10. Reaction between drug substances and pharmaceutical excipients

    DEFF Research Database (Denmark)

    Larsen, Jesper; Cornett, Claus; Jaroszewski, Jerzy Witold;

    2009-01-01

    The reactivity of citric acid towards drug substances in the solid state was examined using the beta-blocker carvedilol as a model compound. The reaction mixtures were analysed by LC-MS, the reaction products were isolated by preparative HPLC, and the structures were elucidated by microprobe NMR...... spectroscopy. Heating a mixture of solid carvedilol and solid citric acid monohydrate for 96h at 50 degrees C resulted in the formation of about 3% of a symmetrical ester as well as of a number of other reaction products in smaller amounts. Formation of the symmetrical ester was also observed at room...... temperature. At 70 degrees C, the amounts of three isomeric esters formed reached 6-8%. The minor reaction products were citric acid amides, O-acetylcarvedilol, and esters of itaconic acid....

  11. Investigating Reaction-Driven Cracking

    Science.gov (United States)

    Kelemen, P. B.; Hirth, G.; Savage, H. M.

    2013-12-01

    for constant volume replacement. Natural examples have fracture energy densities due to strain energy density of 100's of MPa [2]. Despite theory and observation, until now lab experiments on peridotite hydration and carbonation have not produced reaction-driven cracking. Slow kinetics and limited reactive surface area in low porosity samples may be the cause. Also, maximum stress may be limited by 'disjoining pressure', above which nano-films along grain boundaries collapse, and crystal growth essentially ceases [7]. To address these issues, we've begun experiments on analog materials with fast reaction rates, e.g., CaO + H2O = Ca(OH)2, to efficiently investigate the role of confining pressure and other factors on reaction-driven fracture events. Intriguingly, commercially available 'demolition mortar', largely CaO, produces stresses of 70 MPa or more around 1 inch bore holes at room T and P [8], even though there is a free surface at the top of the borehole, and hydration in a 'closed' system creates ~ 40% air-filled pore space. [1] Jamtveit et al EPSL 08 [2] Kelemen & Hirth EPSL 12 [3] Kelemen et al AREPS 11 [4] Aharonov et al JGR 98 [5] Fletcher & Merino GCA 01 [6] Macdonald & Fyfe T'phys 85 [7] Espinosa-Marzal & Scherer GSL Special Papers 10 [8] Laefer et al Mag Concrete Res 10

  12. Developing the reaction kinetics for a biodiesel reactor.

    Science.gov (United States)

    Slinn, Matthew; Kendall, Kevin

    2009-04-01

    The aim of this paper was to investigate the kinetics of the biodiesel reaction in order to find out how best to reach 96.5% methyl ester. The purity of the biodiesel product was examined using gas chromatography to the EN14214 FAME standard and real-time optical microscopy was used to observe the reaction. The problem was the reaction does not reach completion and the mechanism is not understood. It was observed that droplet size had a major influence on reaction end point and that the reaction was mass-transfer limited. This observation was confirmed by developing a mass-transfer based reaction model using the data from the batch reactor which agreed with results from other researchers. The model predicted better conversion with more mixing intensity. The results show that significant improvements could be made to the conventional FAME process.

  13. Oral Hypersensitivity Reactions

    Science.gov (United States)

    ... and ulcers. Affected individuals may complain of a burning sensation and mouth sensitivity to cold, hot, and spicy foods. Lichenoid ... melon, and pineapple, are all associated with this syndrome. You should inform your ... reaction in the mouth, though some are more common than others. If ...

  14. Reaction Formulation: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  15. Explaining competitive reaction effects

    NARCIS (Netherlands)

    Leeflang, P.S.H.; Wittink, D.R.

    2001-01-01

    Changes in promotional expenditure decisions for a brand, as in other marketing decisions, should be based on the expected impact on purchase and consumption behavior as well as on the likely reactions by competitors. Purchase behavior may be predicted from estimated demand functions. Competitive re

  16. The Gewald multicomponent reaction

    NARCIS (Netherlands)

    Huang, Yijun; Doemling, Alexander

    2011-01-01

    The Gewald reaction of sulfur, cyanoacetic acid derivatives, and oxo-component (G-3CR) yielding highly substituted 2-aminothiophene derivatives has seen diverse applications in combinatorial and medicinal chemistry. Its products are of great use in pharmaceutical industry mainly as small molecular w

  17. Managing Your Emotional Reactions

    Science.gov (United States)

    ... takes a bit more practice for some people. Learning to React Well Managing emotional reactions means choosing how and when to express ... easier to make choices that work out well. Learning to react well takes ... at taking emotional situations in stride and expressing emotions in healthy ...

  18. Reaction product imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  19. Chemical Reactions at Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Michael Henderson and Nancy Ryan Gray

    2010-04-14

    Chemical reactions at surfaces underlie some of the most important processes of today, including catalysis, energy conversion, microelectronics, human health and the environment. Understanding surface chemical reactions at a fundamental level is at the core of the field of surface science. The Gordon Research Conference on Chemical Reactions at Surfaces is one of the premiere meetings in the field. The program this year will cover a broad range of topics, including heterogeneous catalysis and surface chemistry, surfaces in environmental chemistry and energy conversion, reactions at the liquid-solid and liquid-gas interface, electronic materials growth and surface modification, biological interfaces, and electrons and photons at surfaces. An exciting program is planned, with contributions from outstanding speakers and discussion leaders from the international scientific community. The conference provides a dynamic environment with ample time for discussion and interaction. Attendees are encouraged to present posters; the poster sessions are historically well attended and stimulate additional discussions. The conference provides an excellent opportunity for junior researchers (e.g. graduate students or postdocs) to present their work and interact with established leaders in the field.

  20. Biomixing by chemotaxis and efficiency of biological reactions: the critical reaction case

    CERN Document Server

    Kiselev, Alexander

    2012-01-01

    Many phenomena in biology involve both reactions and chemotaxis. These processes can clearly influence each other, and chemotaxis can play an important role in sustaining and speeding up the reaction. In continuation of our earlier work, we consider a model with a single density function involving diffusion, advection, chemotaxis, and absorbing reaction. The model is motivated, in particular, by the studies of coral broadcast spawning, where experimental observations of the efficiency of fertilization rates significantly exceed the data obtained from numerical models that do not take chemotaxis (attraction of sperm gametes by a chemical secreted by egg gametes) into account. We consider the case of the weakly coupled quadratic reaction term, which is the most natural from the biological point of view and was left open. The result is that similarly to higher power coupling, the chemotaxis plays a crucial role in ensuring efficiency of reaction. However, mathematically, the picture is quite different in the qua...

  1. Photoneutron reactions in astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Varlamov, V. V., E-mail: Varlamov@depni.sinp.msu.ru; Ishkhanov, B. S.; Orlin, V. N.; Peskov, N. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2014-12-15

    Among key problems in nuclear astrophysics, that of obtaining deeper insight into the mechanism of synthesis of chemical elements is of paramount importance. The majority of heavy elements existing in nature are produced in stars via radiative neutron capture in so-called s- and r processes, which are, respectively, slow and fast, in relation to competing β{sup −}-decay processes. At the same time, we know 35 neutron-deficient so-called bypassed p-nuclei that lie between {sup 74}Se and {sup 196}Hg and which cannot originate from the aforementioned s- and r-processes. Their production is possible in (γ, n), (γ, p), or (γ, α) photonuclear reactions. In view of this, data on photoneutron reactions play an important role in predicting and describing processes leading to the production of p-nuclei. Interest in determining cross sections for photoneutron reactions in the threshold energy region, which is of particular importance for astrophysics, has grown substantially in recent years. The use of modern sources of quasimonoenergetic photons obtained in processes of inverse Compton laser-radiation scattering on relativistic electronsmakes it possible to reveal rather interesting special features of respective cross sections, manifestations of pygmy E1 and M1 resonances, or the production of nuclei in isomeric states, on one hand, and to revisit the problem of systematic discrepancies between data on reaction cross sections from experiments of different types, on the other hand. Data obtained on the basis of our new experimental-theoretical approach to evaluating cross sections for partial photoneutron reactions are invoked in considering these problems.

  2. The human acrosome reaction

    Institute of Scientific and Technical Information of China (English)

    H.W.G.Baker; D.Y.Liu; C.Garrett; M.Martic

    2000-01-01

    We developed tests of sperm-oocyte interaction: sperm-zona binding, zona-induced acrosome reaction, spermzona penetration and sperm-oolemma binding, using oocytes which failed to fertilise in clinical in vitro fertilization (IVF). Although oocyte defects contribute to failure of sperm oocyte interaction, rarely are all oocytes from one woman affected. Low or zero fertilization in standard IVFwas usually caused by sperm abnormalities. Poor sperm-zona pellucida binding was frequently associated with failure of standard IVF and obvious defects of sperm motility or morphology. The size and shape of the acrosome is particularly important for sperm binding to the oocyte. The proportion of acrosome intact sperm in the insemination medium was related to the IVF rate. Inducing the acrosome reaction with a calcium ionophore reduced sperm-zona binding. Blocking acrosome dispersal with an acrosin inhibitor prevented spermzona penetration. Sperm-zona penetration was even more highly related to IVF rates than was sperm-zona binding. Some patients had low or zero fertilization rates with standard IVF but normal sperm by conventional tests and normal sperm-zona binding. Few of their sperm underwent the acrosome reaction on the surface of the zona and none penetrated the zona. In contrast, fertilization and pregnancy rates were high with intracytoplasmic sperm injection. We call thiscondition defective zona pellucida induced acrosome reaction. Discovery of the nature of the abnormalities in the signal transduction and effector pathways of the human zona pellucida induced acrosome reaction should result in simpler tests and treatments for the patients and also provide new leads for contraceptive development.

  3. Nitrile reaction in high-temperature water: Kinetics and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Izzo, B.; Harrell, C.L.; Klein, M.T. [Univ. of Delaware, Newark, DE (United States). Dept. of Chemical Engineering

    1997-08-01

    The reaction pathways, kinetics and mechanisms underlying the hydrolysis of aliphatic and aromatic nitriles in high-temperature water (HTW) were investigated. The reaction products were the associated amides and carboxylic acids. Autocatalytic kinetics were observed and confirmed by experiment and analysis of the physical chemistry of the HTW reaction environment. A model incorporating two autocatalytic steps captured the observed kinetics well, and the associated optimized rate constants highlighted the key differences in the reaction chemistry of aliphatic and aromatic nitriles. The rate behavior of nitrile hydrolysis at these conditions has tangible consequences regarding optimal processing strategies.

  4. Observación de la reacción tisular del precinto comercial de poliamida empleado como método de ligadura en pedículo renal y ute rino en conejos Observation of tissular reaction of commercial polyamide seal used as a method of bond in renal and uterine pedicle in rabbits

    Directory of Open Access Journals (Sweden)

    R Rovere

    2007-01-01

    -absorbables (polypropilene, polyester and polyamide. Staples and vascular clips can also be employed for permanent haemostasia allowing a good occlusion of the vascular pedicles, but their high cost limits their use in veterinary surgery. In this study, tissular reaction at vascular pedicle level was evaluated in rabbits after using a polyamide seal. Six male rabbits underwent nephrectomy and the pedicle was ligatured with polyamide. The remaining six animals underwent ovariohysterectomy with the placement of a seal at uterine cervix level. The haemostasia provided by the implant was immediate and safe after its application. The macroscopic and microscopic observations of the animals showed that the tissular reaction was minimal. Neither tissular necrosis nor a severe inflammation degree were observed during histophatologic studies; nor signs of infection. The polyamide commercial seal is an easy to apply, safe technique, it also causes minimal tissular reaction and has a low cost, making possible its use in vascular pedicle ligatures at surgical veterinary practices.

  5. Metathetical Redox Reaction of (Diacetoxyiodoarenes and Iodoarenes

    Directory of Open Access Journals (Sweden)

    Antoine Jobin-Des Lauriers

    2015-12-01

    Full Text Available The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodoarenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy to access (diacetoxyiodoarenes. A computational study is provided to rationalize the results observed.

  6. 静脉输注核黄素致新生儿局部不良反应的观察和护理体会%Observation and nursing experience on the local adverse reactions of the newborn induced by the intravenous infusion of riboflavin

    Institute of Scientific and Technical Information of China (English)

    杨妩媚

    2014-01-01

    Objective:to grasp the treatment methods for the new born after the use of the riboflavin subcutaneous fluid extravasations.Methods:to pose an individualized use of hirudoid ointment,phento lamine,and magnesium sulfate on the newborn according to the concrete situations.Results:the selected pa-tients received good Results:and no scarring.Conclusions:infusing the riboflavin sodium phosphate to the newborn is prone to the local adverse reactions.But through the active observation and reasonable care measures,the patient newborn can achieve good results.%目的:针对新生儿使用核黄素后液体皮下外渗,了解处理的方法。方法:根据具体反映情况,针对性使用喜疗妥软膏,酚妥拉明,硫酸镁等。结果:所选病例均取的良好效果,无疤痕形成。结论:新生儿输注核黄素磷酸钠容易发生局部不良反应,但通过积极的观察和合理的护理措施,都能取得良好的效果。

  7. 静脉输注核黄素致新生儿局部不良反应的观察和护理体会%Observation and nursing experience on the local adverse reactions of the newborn induced by the intravenous infusion of riboflavin

    Institute of Scientific and Technical Information of China (English)

    杨妩媚

    2014-01-01

    目的:针对新生儿使用核黄素后液体皮下外渗,了解处理的方法。方法根据具体反应情况,针对性使用多磺酸粘多糖乳膏、酚妥拉明、硫酸镁等。结果所选病例均取得良好效果,无瘢痕形成。结论新生儿输注核黄素磷酸钠容易发生局部不良反应,但通过积极的观察和合理的护理措施,都能取得良好的效果。%Objective To grasp the treatment methods for the new born after the use of the riboflavin subcutaneous fluid extravasations.Methods To pose an individualized use of hirudoid ointment, phento lamine, and magnesium sulfate on the newborn according to the concrete situations.Results The selected patients received good results and no scarring.Conclusion Infusing the riboflavin sodium phosphate to the newborn is prone to the local adverse reactions. But through the active observation and reasonable care measures, the patient newborn can achieve good results.

  8. Photooxidative reactions of psoralens

    International Nuclear Information System (INIS)

    The mechanism and biological significance of photooxidative reactions of psoralens are reviewed. Skin-photosensitizing activities of bifunctional and monofunctional psoralens are compared. Antioxidants tocopherols and butilated hydroxytoluene inhibit photochemical reactions of psoralens responsible for induction of erythema. The same antioxidants do not inhibit PUVA-therapy of psriasis. Though psoralens can generate singlet oxygen under UVA-irradiation (315 - 400 nm), nevertheless singlet oxygen does not play significant role in 8-methoxypsoralen (8-MOP) sensitized photooxidation of tocopherol or dihydroxyphenylalanine (DOPA). SH-compounds enhance the rate of 8-MOP sensitized photooxidation of DOPA by a factor of four, simultaneously the rate of oxidation of SH-groups is enhanced many fold in the presence of DOPA. Under UVA-irradiation in organic solvents psoralens are photooxidized. Dimeric photooxidized psoralens are easily destructed in water medium, their destruction induce oxidation of unsaturated lipids and DOPA. (author)

  9. Neutrons from Piezonuclear Reactions

    CERN Document Server

    Cardone, F; Mignani, R; Perconti, W; Petrucci, A; Rosetto, F; Spera, G

    2007-01-01

    We report the results obtained by cavitating water solutions of iron salts (iron chloride and iron nitrate) with different concentrations at different ultrasound powers. In all cases we detected a neutron radiation well higher than the background level. The neutron production is perfectly reproducible and can at some extent be controlled. These evidences for neutron emission generated by cavitation support some preliminary clues for the possibility of piezonuclear reactions (namely nuclear reactions induced by pressure and shock waves) obtained in the last ten years. We have been able for the first time to state some basic features of such a neutron emission induced by cavitation, namely: 1) a marked threshold behavior in power, energy and time; 2) its occurring without a concomitant production of gamma radiation.

  10. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  11. Nuclear reactions from lattice QCD

    Science.gov (United States)

    Briceño, Raúl A.; Davoudi, Zohreh; Luu, Thomas C.

    2015-02-01

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, quantum chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three-nucleon (and higher) interactions in a consistent manner. Currently, lattice quantum chromodynamics (LQCD) provides the only reliable option for performing calculations of some of the low-energy hadronic observables. With the aim of bridging the gap between LQCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from LQCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.

  12. Polymerase chain reaction

    OpenAIRE

    Gaurav Solanki

    2015-01-01

    The polymerase chain reaction (PCR) is a technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications. There are three major steps involved in the PCR technique: denaturation, annealing and extension. PCR is useful in the investigation...

  13. Two photon reactions

    International Nuclear Information System (INIS)

    Some recent results from the field of photon-photon interaction are presented. After a brief general introduction author discusses resonance production, exclusive processes with the four pion final state (γγ→π+π-π+π-), exclusive reaction γγ→psi psi, γγ - 2 body final state and jet production. Total hadronic cross sections for γγ - interactions and the photon structure function are also considered. (M.F.W.)

  14. Photochemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

    1993-12-01

    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  15. [Paranoid syndrome, paranoid reaction, paranoia].

    Science.gov (United States)

    Pavlovský, P

    2006-01-01

    The term paranoid is derived from the Greek word paranoia meaning nadnese. It does not only mean self-reference, but there are various personality features as they are hostility, a tendency towards aggressiveness, irritability, a lack of sense of humour, feelings of overestimation of one-self and a tendency towards accusations. These features may appear also within normal psychology and they becomeclinically important after thein increase of intensity and conspicuousness (los sof hearing, long-term abuse of alcohol and psychostimulants) and organic disorders of the brain may contribute to the development of paranoidity. A mechanism of projection is considered as a decivise factor from the point of view of dynamic psychiatry. Clinically unimportant sign sof paranoidity can be observed due to unusual situations. If a paranoid reaction becomes more serious, formation of a paranoid delusion should be taken to account. In our koncept the term paranoid and paranoidity should be used only as a psychopathological term.

  16. Observation on the adverse reactions and immunological effects in subjects received split influenza A (H1N1) virus vaccine%甲型H1N1流感裂解疫苗的接种反应及免疫效果观察

    Institute of Scientific and Technical Information of China (English)

    吴碧娇; 蔡文安

    2011-01-01

    Objective To observe the adverse reactions and immunological effects in subjects received split influenza A (H1N1) virus vaccine. Methods A total of 43,648 healthy subjects of different groups were immunized with the split influenza A (H1N1) virus vaccine and the adverse reactions and incidence of influenza A (H1N1) were surveyed six onths after vaccination. Results No serious adverse events were occurred to the persons received the vaccine. There 86 persons with the symptoms of cough accompanied with fever and throat pain were randomly sampled for detection of influenza A (H1N1) virus nucleic acid and the results were all negative. Conclusion The split A (H1N1) influenza vaccine demonstrated a good safety and immunological effects.%目的 观察甲型H1N1流感裂解疫苗接种反应及其免疫效果.方法对不同组别的健康人群43 648人进行免疫接种,观察接种反应及完成接种后6个月内甲型H1N1流感发病情况.结果 所有接种对象均未发生即时反应和严重异常反应,出现疑似预防接种异常反应以一般反应为主,未有出现异常和全身强副反应;完成免疫接种后6个月内随机抽查出现发热伴咳嗽、咽痛等症状86人检测甲型H1N1流感病毒核酸均为阴性.结论 甲型H1N1流感裂解疫苗具有良好的安全性和免疫原性.

  17. Observation the vaccination reaction and immune effect of rabies exposed people in Jinrui town during 2009 to 2010%2009-2010年金瑞镇暴露者狂犬病疫苗接种反应及免疫效果观察

    Institute of Scientific and Technical Information of China (English)

    袁和根; 刘莉红

    2012-01-01

    目的 观察人用狂犬病疫苗的接种反应及免疫效果.方法 对金瑞镇2009 -2010年狂犬病疫苗(全程5针)免疫者观察其接种反应并用间接ELISA法检测狂犬病毒抗体.被检对象分为<15岁组、15 ~30岁组、31 ~60岁组和>61岁组.结果 共接种狂犬疫苗609例,免疫后抗体阳性587例,阳性率为96.39%.年龄越小抗体阳性率越高,差异均有统计学意义(P<0.01);女性与男性抗体阳性率差异无统计学意义;不同产地疫苗间的抗体阳性率差异无统计学意义(P>0.05).结论 人用狂犬病疫苗有良好的安全性及免疫原性,但对免疫失败者应加强免疫.%Objective To understand the vaccination reaction and immunization effect of human rabies vaccine. Method Observation the vaccination reaction of rabies exposed people who accepted full course ( five doses ) of rabies vaccine and their antibody against rabies virus was detected by ELISA. The subjects were divided into four groups, less than 15 years old group, 15 and 30 years group, 31 and 60 years group and above 61 years old group. Results Total of 609 persons were inoculation rabies vaccines, 587 cases were antibody positive, the positive rate was 96.39 % (587/609) . There was no statistically significant between male antibody rate to female. With the age-increasing, the positive rates decreased (P 0.05 ) . Conclusions Rabies vaccine showed good safety and irnmunogenicity, but it need to reinforce to the people who's antibody was negative.

  18. Observational exobiology

    Science.gov (United States)

    Tarter, J.

    1986-01-01

    The Earth's atmosphere absorbs partially or completely many ultraviolet, infrared and submillimeter wavelengths. Atmospheric seeing distorts small images, imposing a limit on the achievable angular resolution at optical and infrared wavelengths that is much poorer than the intrinsic capability of telescope optics. The atomic and molecular species of the atmosphere confuse or prevent the spectral studies of similar compounds outside of the terrestrial environment. Telescopes placed in orbit above the atmosphere avoid these problems and enjoy a unique view of the universe. There are many complex questions pertaining to the origin and evolution of the biogenic elements and compounds and the existence of terrestrial types of planets elsewhere that can be only tackled from orbiting facilities. The detailed nature of the spacecraft, platforms and instrumentation most likely to be launched by the United States and Europe in the near future in an attempt to determine what observational programs would be tractable and which areas of interest to exobiology required hardware capabilities beyond those currently envisioned are considered.

  19. On the significance of severe local reactions to Hymenoptera stings.

    Science.gov (United States)

    Abrecht, I; Eichler, G; Müller, U; Hoigné, R

    1980-11-01

    Of 317 patients with hypersensitivity to Hymenoptera stings forty had severe local reactions (SLR) only, fifty-nine reported severe local reactions before their first and seven after their last systemic reaction (SR). The probability to develop a life threatening systemic reaction when restung after a severe local reaction was calculated to be about 5%. In 80% of the patients with severe local reactions only, hypersensitivity to either bee or yellow jacket venom could be demonstrated by skin tests and/or RAST. A fair correlation of skin test and RAST results was observed. In patients with severe local reactions hyposensitization therapy with venoms is not generally indicated. In exceptional patients whose allergy is proven by skin tests or RAST and who are at a high risk of being restung, hyposensitization may be considered.

  20. Astrophysical Reaction Rates as a Challenge for Nuclear Reaction Theory

    OpenAIRE

    Rauscher, T.

    2010-01-01

    The relevant energy ranges for stellar nuclear reactions are introduced. Low-energy compound and direct reactions are discussed. Stellar modifications of the cross sections are presented. Implications for experiments are outlined.

  1. On some microstructural aspects of concrete deterioration

    Directory of Open Access Journals (Sweden)

    Draper, E. A.

    1993-12-01

    Full Text Available There are numerous mechanisms that can lead to deterioration of portland-cement concrete in service. The best known are corrosion of reinforcement, freezing-thawing expansion, alkali-silica reaction, acid attack, and sulfate-related problems, including delayed ettringite formation. Additionally, concrete can deteriorate as a consequence of improper processing, including curing. Often, several of the above mechanisms of deterioration are jointly responsible for the observed damage. This paper briefly reviews the light-optical and electronoptical microscopic methods available to study some of the causes of concrete deterioration, and briefly describes selected case studies. Specifically, microstructural features resulting from physical (e.g., freezing-thawing and chemical (e.g., alkali-silica reaction, delayed ettringite formation deterioration of concrete are highlighted. Corrosion of reinforcement is not discussed.

    Hay numerosos procesos que pueden afectar al hormigón de cemento portland. Los más conocidos son: la corrosión de las armaduras, el efecto expansivo del hielo-deshielo, la reacción álcali-árido, el ataque ácido y los problemas que atañen a los sulfates, incluyendo la formación de ettringita expansiva. Además, el hormigón puede deteriorarse como consecuencia de determinados procesos, entre los que se cuenta el curado. A menudo, más de uno de los mecanismos citados influyen conjuntamente en el daño observado en el hormigón. El presente artículo revisa brevemente métodos de microscopía óptica y electrónica utilizados para estudiar las causas que motivaron deterioro en el hormigón, y resume algún caso seleccionado; concretamente, se destacan los efectos microestructurales que resultan de mecanismos físicos (por ejemplo, de hielo-deshielo y químicos (p.ej., reacción álcali-sílice; formación de ettringita expansiva. No se hace mención de aspectos relativos a corrosión de armaduras.

  2. Emotional reactions to crime across cultures.

    Science.gov (United States)

    Matsumoto, David; Hwang, Hyisung C

    2015-10-01

    Information about the emotions experienced by observers when they witness crimes would have important theoretical and practical implications, but to date no study has broadly assessed such emotional reactions. This study addressed this gap in the literature. Observers in seven countries viewed seven videos portraying actual crimes and rated their emotional reactions to each using 14 emotion scales. Observers reported significantly high levels of negative emotions including anger, contempt, disgust, fear and sadness-related emotions, and anger, contempt and disgust were the most salient emotions experienced by viewers across all countries. Witnesses also reported significantly high levels of positive emotions as well (compared to not feeling the emotion at all), which was unexpected. Country moderated the emotion ratings; post-hoc analyses indicated that masculine-oriented cultures reported less nervousness, surprise, excitement, fear and embarrassment than feminine cultures.

  3. REACTION CHEMISTRY RELATED TO FCC GASOLINE QUALITY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    transfer reactions. All the reactions occurred in the chain termination step are reversible adsorption and desorption processes. The olefins are the products from desorption of carbenium ions. The chain mechanism of n-hexane cracking can be used to well explain the product distribution.   The cracking of n-hexane over Y and Beta zeolites shows high values of CCL. It means that bimolecular reactions of chain propagation proceed to a higher extent. Therefore, Y and Beta zeolites exhibit a higher selectivity for iso-paraffins which are the products only in chain propagation step. Whereas, a low value of CCL observed from small-pore ferrierite zeolite indicates that the monomolecular route is the main cracking pathway. Since the olefins are formed by monomole-cular reaction in chain termination, ZSM-5 and ferrierite zeolites favor the formation of olefins, and the value of CCL of these small-pore zeolites approaches the theoretical minimum value of CCL.   The values of CCL depend also on the reaction temperature, in particular the CCL of Y and Beta zeolites. Our results show that the CCL for n-hexane cracking over HY and ZSM-5 zeolites increases with the increase of reaction temperature, indicating an increasing contribution of the monomolecular reaction in the chain initiation and termination. This can be explained on the basis of the higher activation energy for monomolecular reaction as compared to that for bimolecular reaction in propagation. In addition, the apparent activation energy of the overall reaction and some elementary reactions supports the theoretical postulation of the chain mechanism of n-hexane cracking.    Catalyst design is based on the understanding of the chain mechanism of the cracking reactions and the correlation between CCL and zeolite properties. A new series of GOR catalysts, which stand for “Gasoline olefin reduction” catalysts, has been developed and commercially applied in a number of refineries. The commercial results indicate

  4. Insect bite reactions

    Directory of Open Access Journals (Sweden)

    Sanjay Singh

    2013-01-01

    Full Text Available Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some

  5. Observation and Precaution of Adverse Reaction of Local Hyperthermia Combined With Ra dio-chemotherapy in the Treatment of Patients With Malignant Tumor%热疗联合放疗和化疗治疗恶性肿瘤不良反应的观察与预防

    Institute of Scientific and Technical Information of China (English)

    张淑慧; 刘邦; 杨敬贤; 李庆瑞; 朱长生

    2012-01-01

    Objective: To investigate the causes and precaution of skin scalds of local hyperthermia in the treatment of patients with malignant tumor, and observation of the clinical effects of hyperthermia combined with radio-chemotherapy.Methods: The common complications of 345 patients underwent radiofrequency hyperthermia and 439 cases received microwave hyperthermia from November 1999 to May 2012 were analyzed retrospectively. The prevention measures of pre-treatment,inter-treatment,and post-treatment were provided.Results: All the patients completed the treatment safely and the clinical effect was remarkable. The adverse reaction during and post treatment was observed, there were 9 cases fatty scleroma occurred and no patients had skin burns in radiofrequency hyperthermia;4 Cases superficial II degree skin scalds and 5 cases I degree skin burn occurred in microwave hyperthermia. All the complications disappeared through the treatment and nursing without sequelae. Conclusions: Local tumor hyperthermia combined with radiotherapy、intraperitoneal perfusion chemotherapy and gene therapy is a safe and effective method for various malignant tumors. It improves the therapeutic effects and quality of life obviously for patients, and tolerable adverse reaction. We should comprehensive understand the patient's condition in the process of hyperthermia. Monitoring temperature and putting various nursing measures into practice can effectively prevent skin burn to ensure the patients successfully complete treatment.%目的:探讨在局部热疗中导致肿瘤患者皮肤烫伤的原因和预防对策,观察热疗联合放化疗的临床效果.方法:回顾性分析1999年1 1月至2012年5月我科收治的345例射频热疗患者和439例微波热疗患者的常见并发症,制定热疗前、中、后防范措施.结果:所有患者均安全完成治疗,临床疗效显著.观察治疗中和治疗后不良反应发生的情况,射频热疗中发生脂肪硬结9例,没有患者出现

  6. Organic chemistry: Reactions triggered electrically

    Science.gov (United States)

    Xiang, Limin; Tao, N. J.

    2016-03-01

    Single-molecule experiments have revealed that chemical reactions can be controlled using electric fields -- and that the reaction rate is sensitive to both the direction and the strength of the applied field. See Letter p.88

  7. Observation of complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions: Measurement and analysis of forward recoil ranges at E/A{approx}5-6 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pushpendra P.; Kumar Sharma, Manoj; Unnati; Singh, Devendra P.; Singh, B.P.; Prasad, R. [A. M. University, Accelerator Laboratory, Department of Physics, Aligarh (India); Kumar, Rakesh; Golda, K.S. [Inter-University Accelerator Center, NP Group, P. O. Box No. 10502, New Delhi (India)

    2007-10-15

    With a view to study complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides: {sup 168m}Lu, {sup 167}Lu, {sup 167}Yb, {sup 166}Tm produced in the {sup 16}O+{sup 159}Tb system at {approx}90 MeV, and {sup 179}Re, {sup 177}Re, {sup 177}W, {sup 178}Ta and {sup 177}Hf produced in the {sup 16}O+{sup 169}Tm system at {approx}87 MeV have been measured. The recoil-catcher activation technique followed by off-line {gamma}-spectrometry has been employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations. Different complete- and incomplete-fusion components, which may be attributed to the fusion of {sup 16}O and/or {sup 12}C and {sup 8}Be transfer from the {sup 16}O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given energies. (orig.)

  8. Adverse blood transfusion reactions at tertiary care hospital

    Directory of Open Access Journals (Sweden)

    Surekha K. Chavan

    2016-06-01

    Conclusions: Not a single case of anaphylactic reactions, TRALI, acute immune hemolytic transfusion reaction, and Sepsis was observed. This can be an underestimation of the true incidence because of under reporting which can be improved by proper hemovigilence system to provide better patient care. [Int J Res Med Sci 2016; 4(6.000: 2402-2407

  9. Progress in all-order breakup reaction theories

    Indian Academy of Sciences (India)

    R Chatterjee

    2010-07-01

    Progress in breakup reaction theories, like the distorted wave Born approximation, the continuum discretized coupled channels method and the dynamical eikonal approximation, is brought into focus. The need to calculate exclusive reaction observables and the utility of benchmark tests as arbitrators of theoretical models are discussed.

  10. High stereoselectivity on low temperature Diels-Alder reactions

    Directory of Open Access Journals (Sweden)

    Invernize Paulo

    2005-12-01

    Full Text Available Abstract We have found that some of the usually poor dienophiles (2-cycloenones can undergo Diels-Alder reaction at -78°C with unusually high stereoselectivity in the presence of niobium pentachloride as a Lewis acid catalyst. A remarkable difference in reaction rates for unsubstituted and α- or β-methyl substituted 2-cycloenones was also observed.

  11. Ubiquitous ``glassy'' relaxation in catalytic reaction networks

    Science.gov (United States)

    Awazu, Akinori; Kaneko, Kunihiko

    2009-10-01

    Study of reversible catalytic reaction networks is important not only as an issue for chemical thermodynamics but also for protocells. From extensive numerical simulations and theoretical analysis, slow relaxation dynamics to sustain nonequlibrium states are commonly observed. These dynamics show two types of salient behaviors that are reminiscent of glassy behavior: slow relaxation along with the logarithmic time dependence of the correlation function and the emergence of plateaus in the relaxation-time course. The former behavior is explained by the eigenvalue distribution of a Jacobian matrix around the equilibrium state that depends on the distribution of kinetic coefficients of reactions. The latter behavior is associated with kinetic constraints rather than metastable states and is due to the absence of catalysts for chemicals in excess and the negative correlation between two chemical species. Examples are given and generality is discussed with relevance to bottleneck-type dynamics in biochemical reactions as well.

  12. Oscillatory reactions on single crystal surfaces

    Science.gov (United States)

    Imbihl, R.

    1993-12-01

    Heterogeneous catalytic reactions exhibit under certain conditions kinetic oscillations which have been investigated both with polycrystalline materials and with single crystal surfaces as catalysts. The present paper reviews single-crystal experiments conducted under isothermal, low pressure conditions ( p Turing structures and the appearance of deterministic chaos, and chemical turbulence. The mechanistic steps leading to the observed phenomena have been investigated and appropriate mathematical models have been formulated and analyzed using bifurcation theory. The driving force for the rate oscillations has been shown to result from structural changes of the substrate in the case of catalytic CO oxidation on Pt surfaces, subsurface oxygen formation in the case of catalytic CO oxidation on Pd surfaces, and in the chemical reaction network described by a vacancy model in the case of the NO reduction reactions.

  13. Prompt processes in heavy ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Blann, M.; Remington, B.A.

    1987-12-01

    We test a relaxation model based on two body nucleon-nucleon scattering processes to interpret phenomena observed in heavy ion reactions. We use the Boltzmann Master Equation to accomplish this. By assuming that the projectile nucleons partition the total excitation with equal a-priori probability of all configurations, we are able to reproduce several sets of neutron spectra from /sup 20/Ne and /sup 12/C induced reactions on /sup 165/Ho and from reactions of /sup 40/Ar or /sup 40/Ca. We point out ambiguities in deducing angle-integrated energy spectra from double differential spectra. With no additional free parameters, our model successfully reproduces a large body of high energy ..gamma..-ray spectra by assuming an incoherent n-p-bremsstrahlung mechanism. 45 refs., 13 figs.

  14. A taxonomy of integral reaction path analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grcar, Joseph F.; Day, Marcus S.; Bell, John B.

    2004-12-23

    W. C. Gardiner observed that achieving understanding through combustion modeling is limited by the ability to recognize the implications of what has been computed and to draw conclusions about the elementary steps underlying the reaction mechanism. This difficulty can be overcome in part by making better use of reaction path analysis in the context of multidimensional flame simulations. Following a survey of current practice, an integral reaction flux is formulated in terms of conserved scalars that can be calculated in a fully automated way. Conditional analyses are then introduced, and a taxonomy for bidirectional path analysis is explored. Many examples illustrate the resulting path analysis and uncover some new results about nonpremixed methane-air laminar jets.

  15. The nuclear reaction matrix

    Energy Technology Data Exchange (ETDEWEB)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.

    1976-09-24

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the Aapprox. =18 region are performed following this procedure and treating the Pauli exclusion operator Q/sub 2//sub p/ by the method of Tsai and Kuo. The treatment of Q/sub 2//sub p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close agreement is obtained with the matrix elements calculated by Kuo and Brown using approximate methods. (AIP)

  16. Reaction Profiles and Molecular Dynamics Simulations of Cyanide Radical Reactions Relevant to Titan's Atmosphere

    Science.gov (United States)

    Trinidad Pérez-Rivera, Danilo; Romani, Paul N.; Lopez-Encarnacion, Juan Manuel

    2016-10-01

    Titan's atmosphere is arguably the atmosphere of greatest interest that we have an abundance of data for from both ground based and spacecraft observations. As we have learned more about Titan's atmospheric composition, the presence of pre-biotic molecules in its atmosphere has generated more and more fascination about the photochemical process and pathways it its atmosphere. Our computational laboratory has been extensively working throughout the past year characterizing nitrile synthesis reactions, making significant progress on the energetics and dynamics of the reactions of .CN with the hydrocarbons acetylene (C2H2), propylene (CH3CCH), and benzene (C6H6), developing a clear picture of the mechanistic aspects through which these three reactions proceed. Specifically, first principles calculations of the reaction profiles and molecular dynamics studies for gas-phase reactions of .CN and C2H2, .CN and CH3CCH, and .CN and C6H6 have been carried out. A very accurate determination of potential energy surfaces of these reactions will allow us to compute the reaction rates which are indispensable for photochemical modeling of Titan's atmosphere.The work at University of Puerto Rico at Cayey was supported by Puerto Rico NASA EPSCoR IDEAS-ER program (2015-2016) and DTPR was sponsored by the Puerto Rico NASA Space Grant Consortium Fellowship. *E-mail: juan.lopez15@upr.edu

  17. Zeolite Catalyzed Aldol Condensation Reactions

    OpenAIRE

    Adedayo I. Inegbenebor; Raphael C. Mordi; Oluwakayode M. Ogunwole

    2015-01-01

    The review is based on the description of zeolite structure, uses, synthesis, and catalytic aldol reaction in aldol condensation. An internal aldolcondensation reaction has been achieved over ZSM-5 zeolite with high silica-alumina ratio at 350oC. It therefore follows that zeolite canfunction as a catalyst in aldol type condensation reactions and that weak acid sites as well as a small number of active sites favor the aldolcondensation reaction of carbonyl compounds. However, the mixed condens...

  18. ASR potential of quartz based on expansion values and microscopic characteristics of mortar bars

    Science.gov (United States)

    Stastna, Aneta; Sachlova, Sarka; Kuchynova, Marketa; Pertold, Zdenek; Prikryl, Richard

    2016-04-01

    The alkali-silica reaction (ASR) is one of the most damaging factors for concrete structures. Different analytical techniques are used to quantify ASR potential of aggregates. The accelerated mortar bar test (ASTM C1260) in combination with the petrographic examination of aggregates by microscopic techniques belongs to the frequently employed methods. Such a methodical approach enables quantification of the ASR potential, based on the expansion values of accelerated mortar bars; and also to identify deleterious components in aggregates. In this study, the accelerated mortar bar test (ASTM C1260) was modified and combined with the scanning electron microscopy of polished sections prepared from mortar bars. The standard 14-day test period of mortar bars was prolonged to 1-year. ASR potential of aggregates was assessed based on expansion values (both 14-day and 1-year) of mortar bars and microscopic analysis of ASR products (alkali silica gels, microcracks, dissolution gaps) detected in the sections. Different varieties of quartz-rich rocks including chert, quartz meta-greywacke, three types of quartzite and pegmatite were used as aggregate. Only quartz from pegmatite was assessed to be non reactive (14-day expansion of 0.08%, 1-year expansion of 1.25%). Aggregate sections exhibited minor ASR products even after 1-year of mortar bar immersion in 1 M NaOH. Expansion values of the rest of samples exceeded the limit of 0.10% after 14-day test period indicating aggregates as reactive. The highest ASR potential was detected in mortar bars containing chert (14-day expansion of 0.55%, 1-year expansion of 2.70%) and quartz meta-greywacke (14-day expansion of 0.46%, 1-year expansion of 2.41%). The high ASR potential was explained by presence of cryptocrystalline matrix in significant volumes (24 - 65 vol%). Influence of the lengths of the immersion in the alkaline solution was observed mainly in the microstructure of the cement paste and on the extension of ASR products. The

  19. Mass Transfer with Chemical Reaction.

    Science.gov (United States)

    DeCoursey, W. J.

    1987-01-01

    Describes the organization of a graduate course dealing with mass transfer, particularly as it relates to chemical reactions. Discusses the course outline, including mathematics models of mass transfer, enhancement of mass transfer rates by homogeneous chemical reaction, and gas-liquid systems with chemical reaction. (TW)

  20. Status of breakup reaction theory

    International Nuclear Information System (INIS)

    Recent studies on breakup reactions with the continuum-discretized coupled-channels method are reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, dynamical relativistic effects on Coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple-α reaction rate) and new approach to inclusive breakup processes.

  1. 以索拉非尼为基础治疗晚期肝细胞癌的疗效和不良反应临床观察%Clinical observation on efficacy and adverse reactions of sorafenib in treating advanced hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    苑珩珩; 白玉贤; 张婷婷; 黄鹏

    2012-01-01

    Background and purpose: Two clinical trials SHARP and ORIENTAL confirmed that sorafenib, a multi-kinase inhibitor could significantly improve PFS as well as TTP, and prolong OS for patients with hepatocellular carcinoma. Therefore sorafenib was approved to treat advanced hepatocellular carcinoma in 2008. Our study was designed to observe efficacy and adverse reactions of sorafenib alone or in combination with TACE in treating 30 patients with advanced hepatocellular carcinoma. Methods: From Mar 2009 to Jan 2011, a total of 30 patients with clinical or pathological diagnosis of advanced primary hepatocellular carcinoma orally took sorafenib with dosage of 400 mg each time, 2 times a day, and treatment duration was at least more than 2 months. Twenty patients received TACE for 1 to 9 times in combination with sorafenib, and 10 patients took sorafenib alone. In accordance with RESIST, efficacy was evaluated each two-month and follow-up was performed to achieve TTP and OS. Results: Among 30 patients, there were 3 patients of PR, 16 patients of SD, and 11 patients of PD, with clinical benefit rate (CBR) of 63.3%. Among 10 patients who took sorafenib alone, there were 1 patient of PR, 5 patients of SD, and 4 patients of PD, with CBR of 60.0%. Among 20 patients who took sorafenib in combination with TACE, there were 2 patients of PR, 11 patients of SD, and 7 patients of PD, with CBR of 65.0%. All 27 patients survived for more than 3 months, 24 patientssurvived for more than 6 months, 21 patients survived for more than 9 months, and 9 patients survived for even more than 1 year. TTP was 7 months, and OS was 9 months, with P=0.067 2 and P=0.058 9. Patients demonstrated adverse effects 1-2 weeks after administration. Twenty-three patients had hand and foot symptom, 24 patients had diarrhea, 14 patients had hypertension, 24 patients had fatigue, 9 patients had hair loss. There were 10 cases of degree 3 adverse reaction in total, and patients could accomplish the whole therapy

  2. Recyclable hydrotalcite clay catalysed Baylis-Hillman reaction

    Indian Academy of Sciences (India)

    Vivek Srivastava

    2013-09-01

    The Baylis-Hillman reaction using ionic liquid/hydrotalcite clay catalytic system has been observed to be more reactive in terms of yield and reaction rate than DABCO/acetonitrile system. During the process, the reactants enjoy ionic liquid/hydrotalcite clay catalytic system and gives corresponding Baylis-Hillman reaction products in good yield. The application of our catalytic system has been diversifying for the synthesis of lactone ceramide analogue from (S)-Garner aldehyde-methyl acrylate using Baylis-Hillman reaction. Recycling of ionic liquid/hydrotalcite clay catalytic system has also been demonstrated in this report.

  3. The Influence Factors of the BZ Oscillating Reaction

    Institute of Scientific and Technical Information of China (English)

    LIU XiuHui; GAO JinZhang

    2001-01-01

    @@ As a typical oscillating chemical reaction, studies of the Belousov-Zhabotinsky reaction have not only yielded important results to provide insights to many kinetic and thermodynamic problems, but also provided suggestive models for a number of important biological processes. Now the BZ reaction has become a useful experimental model for studying nonlinear phenomena in distributed systems. We carried out a systematic study of the influence factors on the BZ reaction in a closed system, and some new observations are reported here forthe first time.

  4. The Influence Factors of the BZ Oscillating Reaction

    Institute of Scientific and Technical Information of China (English)

    LIU; XiuHui

    2001-01-01

    As a typical oscillating chemical reaction, studies of the Belousov-Zhabotinsky reaction have not only yielded important results to provide insights to many kinetic and thermodynamic problems, but also provided suggestive models for a number of important biological processes. Now the BZ reaction has become a useful experimental model for studying nonlinear phenomena in distributed systems. We carried out a systematic study of the influence factors on the BZ reaction in a closed system, and some new observations are reported here forthe first time.  ……

  5. Linear free energy relationship in reactions between diphenyl amine and benzyl bromides

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2006-05-01

    Rate of reaction between benzyl bromide and diphenyl amine is retarded by electron-donating groups and enhanced by electron-withdrawing groups present on the benzene ring of the substrate. Hammett's reaction constant of the reaction decreases with increase in temperature according to the equation, \\rho = -11.92 + 3.54/ T. Minimal structural effects observed are attributed to the fact that the isokinetic temperature of the reaction is close to the reaction temperature.

  6. Nuclear reactions an introduction

    CERN Document Server

    Paetz gen. Schieck, Hans

    2014-01-01

    Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown – mainly by performing scattering experiments with electrons, muons, and neutrinos – to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction.   The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no ...

  7. Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-10-01

    Full Text Available The polymerase chain reaction (PCR is a technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications. There are three major steps involved in the PCR technique: denaturation, annealing and extension. PCR is useful in the investigation and diagnosis of a growing number of diseases. PCR is also used in forensics laboratories. PCR can identify genes that have been implicated in the development of cancer. The present paper is an attempt to review basics of PCR in relation to its methods, application and use.

  8. Eikonal reaction theory

    CERN Document Server

    Yahiro, Masanobu; Minomo, Kosho

    2011-01-01

    We present an accurate method of treating the one-neutron removal reaction at intermediate incident energies induced by both nuclear and Coulomb interactions. In the method, the nuclear and Coulomb breakup processes are consistently treated by the method of continuum discretized coupled channels without making the adiabatic approximation to the Coulomb interaction, so that the removal cross section calculated never diverges. This method is applied to recently measured one-neutron removal cross section for $^{31}$Ne+$^{12}$C scattering at 230 MeV/nucleon and $^{31}$Ne+$^{208}$Pb scattering at 234 MeV/nucleon. The spectroscopic factor and the asymptotic normalization coefficient of the last neutron in $^{31}$Ne are evaluated.

  9. The effect of catalyst support on the RWGS reaction

    International Nuclear Information System (INIS)

    'Full text:' Methane steam reforming is generally applied in order to produce synthesis gas mainly consist of hydrogen and carbon monoxide for later utilization in SOFC. This reaction is always carried out with the water gas shift reaction over a catalyst at elevated temperatures resulting in some carbon dioxide production. The CO/CO2 production selectivity strongly depends on the influence of water gas shift reaction. It was observed that the reactivity of this reaction depended on the type of support material. Stabilities, activities, and kinetics of the reverse water gas shift reaction (RWGS) for commercial nickel on CeO2, ZrO2, CeO2-ZrO2, TiO2, MgO, and Al2O3 supports were studied in order to observe the influence of the support on this reaction. According to the experiment, the activities of Ni/CeO2 toward the reverse water gas shift reaction (RWGS) were very high, and reached equilibrium level at approximately 600oC (where the conversion of CO2 was closed to 1). Other oxide supports provided lower activities toward this reaction. It was observed that the activity of Ni/Al2O3 toward this reaction was the lowest. The kinetics of this reaction was also studied. Carbon dioxide presented positive effect on the reverse water gas shift reaction. The reaction orders in carbon dioxide were observed to be positive partial value between 0-1. It slightly decreased with increasing temperature for Ni/ CeO2 and Ni/CeO2-ZrO2, whereas it seemed to be independent of the operating temperature for other materials in the range of conditions studied. Hydrogen also showed positive effect on the reverse water gas shift reaction for all materials. The reaction order in hydrogen for all materials was observed to be the positive value and less than one for the range of conditions studied. The approximate values for all catalysts were between 0.45-0.65, and seemed to be independent of the operating temperature. The estimated values of the apparent activation energy for RWGS reaction

  10. Kinetics of Bio-Reactions

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions....... The models can be used in mass balances for design of processes under process conditions not yet studied experimentally. The value of the predictive kinetic model depends on the quality of the experimental data on which the model is based, and well-founded kinetic models for enzyme reactions have...... a considerable predictive power. This is also true for cell reaction models, when the model is used in its proper context. The chapter first discusses the kinetics for enzymatically catalyzed reactions (“enzyme reactions”). The kinetics can be derived from a mechanistic model. Then, the chapter derives empirical...

  11. 右美托咪啶用于预防经尿道前列腺电切术中寒战反应的临床观察%Clinical observation of dexmedetomidine for the prevention of shivering reaction in transurethral resection of the prostate

    Institute of Scientific and Technical Information of China (English)

    靳红绪; 魏兰双; 王立红; 徐志杰; 张同军; 孙学飞; 王福朝; 王忠义

    2014-01-01

    Objectives To investigate the effect of dexmedetomidine for the prevention of shivering reaction in transurethral resection of the prostate(TURP).Methods A total of 120 patients undergoing selective TURP,aged 56 to 82 years,ASA grade Ⅰ or Ⅱ,were randomly divided into two groups with 60 cases each.After combined spinal epidural anesthesia,group D received intravenous infusion of dexmedetomidine at the dose of 3 μg · (kg · h)-1 within 10 min and then 0.4μg · (kg · h)-1 until 30 min before the end of operation.Group C received intravenous infusion of equal volume of normal saline with same way.Changes of heart rate(HR),mean arterial pressure (MAP),respiratory rate(RR),pulse oxygen saturation(Sp02) and occurrence rate and degree of shivering at each point were observed and recorded.Results There were no significant differences of hemodynamic and respiratory parameters at any time point between the two groups (P > 0.05).The rate of shivering occurrence and scores of shivering in group D were significantly lower than those of group C (P < 0.05).Conclusions Dexmedetomidine is deemed as safe,reliable and feasible to prevent the shivering reaction in TURP.%目的 观察右美托咪啶用于预防经尿道前列腺电切术(TURP)中患者发生寒战反应的效果.方法 择期拟行TURP的患者120例,年龄56~ 82岁,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为2组,每组60例.腰硬联合麻醉后D组采用静脉泵注右美托咪啶3μg·(kg·h)-1,10 min后调整输注速度为0.4μg·(kg·h)-1,术毕前30 min停止输注.C组则按相同方法泵注等量生理盐水.观察并记录两组患者泵注药物前及泵注后各时点心率(HR)、平均动脉压(MAP)、呼吸频率(RR)、血氧饱和度(SpO2)的变化;并观察寒战发生率和寒战程度分级等情况.结果 两组患者术中血流动力学及呼吸均保持平稳,比较差异无统计学意义(P>0.05);D组寒战反应发生率及寒战程

  12. The role of van der Waals interactions in chemical reactions

    International Nuclear Information System (INIS)

    We are studying the role of van der Waals interactions in the chemical reactions from the theoretical view point, especially, a case related to the tunnel effect. The fist case that the cumulative reaction probability depends on the tunnel effect was increased by the van der waals force. This case was proved by theoretical calculation of the reaction rate constant of the reaction: Mu + F2 → MuF + F. The second case was that a van der Waals well was so deep that pseudo bound state was observed in the reaction: F + H2 → HF + H. A van der Waals complex such as AB(v=j=0)...C was excited to the resonance state of AB(vij)...C and A...BC(v,j) by laser, than the resonance state proceeded to AB + C (predissociation) or A + BC(pre-reaction). We succeeded for the first time to calculate theoretically the pre-reaction by the real three dimentional potential curve. The pre-reaction can be observed only the case that the tunnel probability is larger than the non-adiabatic transition probability. The chemical reactions in solid were explained, too. (S.Y.)

  13. The hunt for the dynamical resonances in chemical reaction dynamics: a perspective on historical advances

    Directory of Open Access Journals (Sweden)

    Yu Angyang

    2015-06-01

    Full Text Available The theoretical background and basic definition of the resonances in chemical reaction dynamics have been introduced in this article. The historical breakthrough in the experimental search for the reaction resonances has been reviewed in this report, with an emphasis on the crossed molecular beam apparatus. The research of the chemical reaction resonances has attracted many scientists’ attention from 80s of last century. The chemical reaction resonances in the F+H2 reaction were firstly observed by the researchers of the Chinese Academy of Sciences in 2006. Besides, the partial wave resonances in the chemical reactions have been observed for the first time in 2010.

  14. Crossed molecular beam studies of unimolecular reaction dynamics

    International Nuclear Information System (INIS)

    The study of seven radical-molecule reactions using the crossed molecular beam technique with supersonic nozzle beams is reported. Product angular and velocity distributions were obtained and compared with statistical calculations in order to identify dynamical features of the reactions. In the reaction of chlorine and fluorine atoms with vinyl bromide, the product energy distributions are found to deviate from predictions of the statistical model. A similar effect is observed in the reaction of chlorine atoms with 1, 2 and 3-bromopropene. The reaction of oxygen atoms with ICl and CF3I has been used to obtain an improved value of the IO bond energy, 55.0 +- 2.0 kcal mol-1. In all reactions studied, the product energy and angular distributions are found to be coupled, and this is attributed to a kinematic effect of the conservation of angular momentum

  15. FDI report on adverse reactions to resin-based materials.

    Science.gov (United States)

    Fan, P L; Meyer, D M

    2007-02-01

    Resin-based restorative materials are considered safe for the vast majority of dental patients. Although constituent chemicals such as monomers, accelerators and initiators can potentially leach out of cured resin-based materials after placement, adverse reactions to these chemicals are rare and reaction symptoms commonly subside after removal of the materials. Dentists should be aware of the rare possibility that patients could have adverse reactions to constituents of resin-based materials and be vigilant in observing any adverse reactions after restoration placement. Dentists should also be cognisant of patient complaints about adverse reactions that may result from components of resin-based materials. To minimise monomer leaching and any potential risk of dermatological reactions, resin-based materials should be adequately cured. Dental health care workers should avoid direct skin contact with uncured resin-based materials. Latex and vinyl gloves do not provide adequate barrier protection to the monomers in resin-based materials.

  16. Ubiquitous "glassy" relaxation in catalytic reaction networks

    OpenAIRE

    Awazu, Akinori; Kaneko, Kunihiko

    2009-01-01

    Study of reversible catalytic reaction networks is important not only as an issue for chemical thermodynamics but also for protocells. From extensive numerical simulations and theoretical analysis, slow relaxation dynamics to sustain nonequlibrium states are commonly observed. These dynamics show two types of salient behaviors that are reminiscent of glassy behavior: slow relaxation along with the logarithmic time dependence of the correlation function and the emergence of plateaus in the rel...

  17. Progress Towards a Positron Reaction Microscope

    OpenAIRE

    Williams, A. I.; Kover, A.; Murtagh, D. J.; Laricchia, G

    2010-01-01

    The progress toward the construction of a positron reaction microscope is outlined. The design principles of an electrostatic lens system used to focus and transport the positron beam with a similar to 1 mm diameter spot are briefly discussed. Also presented here are the results obtained from the characterisation of the supersonic gas jet assembly, an increased peaking factor of similar to 4 has been observed along with a centerline density of 10(12) cm(-3).

  18. Photocatalytic reaction on photofuel cell titania electrode

    OpenAIRE

    Nishikiori, Hiromasa; Kato, Yotaro

    2012-01-01

    Benzoic acid-doped titania electrodes were prepared from titanium alkoxide sols containing benzoic acid in order to examine the photocatalytic reaction of the fuel material concentrated on the titania surface of a photofuel cell electrode. This doping was developed in order to understand the physicochemical processes on the titania rather than to advance the practical use of the photofuel cells. The observed photocurrent and CO(2) and H(2)O productions indicated that the oxidation of the benz...

  19. The Effectiveness of High Quality Supplementary Cementitious Materials for Mitigating ASR Expansion in Concrete with High Alkali Content

    Directory of Open Access Journals (Sweden)

    I. Prasetia

    2015-10-01

    Full Text Available Alkali silica reaction (ASR is influenced by external factors such as the surrounding environment of high alkalinity. Countries with cold climate have a high probability to be exposed to high concentrations of NaCl solution by the deicing salt. This condition will lead to serious ASR problems in concrete, if the aggregates contain reactive silica. The main research work in this paper is to investigate the effect of 15% replacement ratio of high quality fine fly ash (FA15% and 42% replacement ratio of blast furnace slag (BFS42% on the ASR mitigation in concrete with different alkali amount inside the pore solution. The experiments were conducted according to the accelerated mortar bars experiment following the JIS A1146 mortar bar test method. In addition, post-analysis such as observation of ASR gel formation by the Uranyl Acetate Fluorescence Method and observation of thin sections using a Polarizing Microscope were also conducted. The mortar bar tests show a very good mitigation effect of supplementary cementitious materials (SCMs. The results show that only small ASR expansions, which can be categorized as “innocuous”, occurred for specimens with 1.2% Na2Oeq using FA15% and BFS42%. However, larger alkali amount inside the system will require more SCMs amount.

  20. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    CERN Document Server

    Kolb, Jakob J; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  1. Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution

    International Nuclear Information System (INIS)

    Highlights: ► Gasification of sugarcane bagasse has been investigated using a semi batch reactor. ► Global reaction mechanism combining pyrolysis and gasification reactions is presented. ► High flow rates of syngas supported fragmentation and secondary reactions. ► CO flow rate increased at higher heating rates at the expense of CO2 production. ► At high temperatures merger between pyrolysis and char gasification occurs. -- Abstract: Steam gasification of sugarcane bagasse has been investigated. A semi batch reactor with a fixed amount of sugarcane bagasse sample placed in steady flow of high temperature steam at atmospheric pressure has been used. The gasification of bagasse was examined at reactor and steam temperatures of 800, 900 and 1000 °C. The evolution of syngas flow rate and chemical composition has been monitored. The evolution of chemical composition and total flow rate of the syngas has been used to formulate a global reaction mechanism. The mechanism combines pyrolysis reaction mechanisms from the literature and steam gasification/reforming reactions. Steam gasification steps include steam–hydrocarbons reforming, char gasification and water gas shift reactions. Evidence of fragmentation, secondary ring opening reactions and tertiary reactions resulting in formation of gaseous hydrocarbons is supported by higher flow rates of syngas and hydrogen at high heating rates and high reactor temperatures. Increase in carbon monoxide flow rate at the expense of carbon dioxide flow rate with the increase in reactor temperature has been observed. This increase in the ratio of CO/CO2 flow rate confirms the production of CO and CO2 from the competing reaction routes. At 1000 °C gasification a total merging between the pyrolysis step and the char gasification step has been observed. This is attributed to acceleration of char gasification reactions and acceleration of steam–hydrocarbons reforming reactions. These hydrocarbons are the precursors to char

  2. Transient ion ejection during nanocomposite thermite reactions

    Science.gov (United States)

    Zhou, Lei; Piekiel, Nicholas; Chowdhury, Snehaunshu; Lee, Donggeun; Zachariah, Michael R.

    2009-10-01

    We observe an intense ion pulse from nanocomposite thermite reactions, which we temporally probe using a recently developed temperature jump/time of flight mass spectrometer. These ion pulses are observed to be much shorter in duration than the overall thermite reaction time. Ion ejection appears in stages as positive ions are ejected prior to nanocomposite thermite ignition, and ignition of the thermite mixtures leads to a second ionization step which is primarily dominated by negative species. The positive species are identified from mass spectrometric measurements and the results show that the positive ion species are comprised of Na ions with minor species of Al and K ions. This observation can be explained by a diffusion based ion-current mechanism, in which strong Al ion diffusion flux formed through the oxide shell, and the surface Na and K ions from salt contaminations are ejected by the strong electrostatic repulsion. The fact that the negative ionization step occurs during the ignition event suggests a strong relation between the nanocomposite thermite reaction and the negative ionization process.

  3. clinic observation of compound recombinant human interleukin-11 solution in prevention and treatment of radiotherapy-induced oral mucositis reaction in patients with nasopharyngeal carcinoma%重组人白介素-11在防治鼻咽癌放射性口腔粘膜炎的疗效观察

    Institute of Scientific and Technical Information of China (English)

    蓝余钒; 张绪慧; 汤新跃

    2015-01-01

    Objective To observe the efficacy of recombinant human interleukin-11 ( IL-11) in treatment of oral mucositis related with nasopharyngeal carcinoma(NPC) radiotherapy.Methods 58 cases (from Mar 2013 to Dec 2014) with NPC were randomly divided into the observation group (recombinant human interleukin -11 group n = 30) and the control group (nomal saline group n = 28) . The patients were given conventional treatment if oral mucositis grade were II –IV.Results 1.The incidences of grade I were 46.7% , 3.60% and the incidences of grade III were 16.7%, 42.8% in the observation group and control group respectively(P < 0. 05) .2. in the observation group, the rate of radioactive mucositis at 20Gy and 30Gy was 33.3% and 63.4% respectively, which in the control group was 78.5% and 21.5% respectively(P < 0. 05). 3. The median time of occurrence on radiation mucositis in the observation group and in the control group was 18 and 11days respectively (P < 0. 05). 4. The mean time for radioactive oral mucositis of grade III lasting in the observation group and in the control group was 8.2 and 11.4 days respectively(P < 0. 05).Conclusions Compound recombinant human interleukin-11 solution is effective to prevent and treat the radiotherapy - induced oral mucositis reaction. It has no side effects. So it is valuable for clinical application.%目的:观察重组人白介素-11( IL-11)在防治鼻咽癌放射治疗相关性口腔粘膜炎的疗效。方法选取2013年3月~2014年12月在我院肿瘤科就诊的鼻咽癌患者58例,随机分为重组人白介素-11组(n=30)及生理盐水组(n=28),从放疗第一天开始至放疗,当两组患者出现II级及以上口腔粘膜炎时予常规对症处理。观察两组黏膜炎发生率,发生时间,反应程度及不了反应等。结果1.重组人白介素-11组和对照组I级与III级粘膜炎发生率分别为46.7%和3.60%,16.7%和42.8%(P<0.05);2.在照射剂量达20Gy及30Gy时,白介素-11组口腔

  4. Hemolytic Transfusion Reactions

    Directory of Open Access Journals (Sweden)

    Fatih Mehmet Azık

    2011-12-01

    Full Text Available The prevalence of fatal hemolytic transfusion reactions (HTRs is approximately 1:200000 per unit. Acute HTRs occur during or within 24 h after administration of a blood product. Transfusion of incompatible red blood cells (RBCs, and, more rarely, of a large volume of incompatible plasma usually are the causative agents. Delayed HTRs are caused by a secondary immune response to an antigen on the donor’s RBCs. Different mechanisms lead to intra- and extravascular hemolysis, such as complete complement activation, phagocytosis of RBCs covered with C3b by macrophages after incomplete complement activation, or destruction of RBCs covered only with IgG by direct cell to cell contact with K cells. The clinical consequences of HTRs are triggered via several pathophysiological pathways. Formation of anaphylatoxins, release of cytokines causing a systemic inflammatory response syndrome, activation of the kinin system, the intrinsic clotting cascade and fibrinolysis result in hypotension, disseminated intravascular coagulation, diffuse bleeding, and disruption of microcirculation leading to renal failure and shock. In this review, the symptoms of HTR are introduced, laboratory investigations and treatment are described, and some recommendations for prevention are given. (Journal of Current Pediatrics 2011; 9: 127-32

  5. Two chamber reaction furnace

    Science.gov (United States)

    Blaugher, Richard D.

    1998-05-05

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  6. [Electromagnetic studies of nuclear structure and reactions

    International Nuclear Information System (INIS)

    The experimental goals are focused on developing an understanding of strong interactions and the structure of hadronic systems by determination of the electromagnetic response; these goals will be accomplished through coincidence detection of final states. Nuclear modeling objectives are to organize and interpret the data through a consistent description of a broad spectrum of reaction observables; calculations are performed in a nonrelativistic diagrammatic framework as well as a relativistic QHD approach. Work is described according to the following arrangement: direct knockout reactions (completion of 16O(e,e'p), 12C(e,e'pp) progress, large acceptance detector physics simulations), giant resonance studies (intermediate-energy experiments with solid-state detectors, the third response function in 12C(e,e'p0) and 16O(e,e'p0), comparison of the 12C(e, e'p0) and 16O(e,e'p3) reactions, quadrupole strength in the 16O(e,e'α0) reaction, quadrupole strength in the 12C(e,e'α) reaction, analysis of the 12C(e,e'p1) and 16O(e,e'p3) angular distributions, analysis of the 40Ca(e,e'x) reaction at low q, analysis of the higher-q 12C(e,e'x) data from Bates), models of nuclear structure (experimental work, Hartree-Fock calculations, phonon excitations in spherical nuclei, shell model calculations, variational methods for relativistic fields), and instrumentation development efforts (developments at CEBAF, CLAS contracts, BLAST developments)

  7. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  8. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  9. The Paterno-Buchi reaction

    DEFF Research Database (Denmark)

    Brogaard, Rasmus Yding; Schalk, Oliver; Boguslavskiy, Andrey E.;

    2012-01-01

    .2]paracyclophane in order to obtain a model system in pre-reactive conformation for the PB reaction. We studied the excited-state dynamics of the isolated molecule in a molecular beam using femtosecond time-resolved photoelectron spectroscopy and ab initio calculations. The results show that inter-system crossing...... within two picoseconds competes efficiently with the reaction in the singlet manifold. Thus, the PB reaction in this model system takes place in the triplet state on a time scale of nanoseconds. This result stresses the importance of triplet states in the excited-state pathway of the PB reaction......The Paternò-Büchi (PB) reaction between an excited carbonyl compound and an alkene has been widely studied, but so far little is known about the excited-state dynamics of the reaction. In this investigation, we used a compound in which a formyl and a vinyl group are attached to a [2...

  10. The Glaser–Hay reaction

    DEFF Research Database (Denmark)

    Vilhelmsen, Mie Højer; Jensen, Jonas; Tortzen, Christian;

    2013-01-01

    on the scope of this reaction by using both 13C NMR and UV/Vis spectroscopic methods. The former method was used to study the kinetics of the coupling of aryl-substituted alkynes as the aryl carbon resonances of the reactants and products have similar NOEs and relaxation times. The reaction was found......), was found to have a significant effect on the rate of the reaction: The percentage of alkyne remaining after a certain time decreased linearly with the rate of stirring. On the basis of systematic studies, the optimized conditions for the coupling reaction using CuCl/TMEDA as the catalyst system......The oxidative Glaser–Hay coupling of two terminal alkynes to furnish a butadiyne is a key reaction for acetylenic scaffolding. Although the reaction is performed under rather simple conditions [CuCl/TMEDA/O2 (air)], the mechanism is still under debate. Herein we present detailed studies...

  11. Electrophilic Substitution Reactions of Indoles

    Science.gov (United States)

    Sundberg, Richard J.

    The topic of this chapter is electrophilic substitution of indole and its derivatives. The indole ring is highly reactive at its 3-position toward protonation, halogenation, alkylation and acylation. Electrophilic substitution can be combined with inter- or intramolecular addition at C-2. Intramolecular alkylation by iminium ions (Pictet-Spengler reaction) is particularly useful. Enantioselectivity can be achieved in many conjugate addition reactions. These reactions have been applied to synthesis of both natural products and drugs.

  12. Nuclear astrophysics from direct reactions

    OpenAIRE

    2008-01-01

    Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation.

  13. Glycation Reactions of Casein Micelles.

    Science.gov (United States)

    Moeckel, Ulrike; Duerasch, Anja; Weiz, Alexander; Ruck, Michael; Henle, Thomas

    2016-04-13

    After suspensions of micellar casein or nonmicellar sodium caseinate had been heated, respectively, in the presence and absence of glucose for 0-4 h at 100 °C, glycation compounds were quantitated. The formation of Amadori products as indicators for the "early" Maillard reaction were in the same range for both micellar and nonmicellar caseins, indicating that reactive amino acid side chains within the micelles are accessible for glucose in a comparable way as in nonmicellar casein. Significant differences, however, were observed concerning the formation of the advanced glycation end products (AGEs), namely, N(ε)-carboxymethyllysine (CML), pyrraline, pentosidine, and glyoxal-lysine dimer (GOLD). CML could be observerd in higher amounts in nonmicellar casein, whereas in the micelles the pyrraline formation was increased. Pentosidine and GOLD were formed in comparable amounts. Furthermore, the extent of protein cross-linking was significantly higher in the glycated casein micelles than in the nonmicellar casein samples. Dynamic light scattering and scanning electron microscopy showed that glycation has no influence on the size of the casein micelles, indicating that cross-linking occurs only in the interior of the micelles, but altered the surface morphology. Studies on glycation and nonenzymatic cross-linking can contribute to the understanding of the structure of casein micelles. PMID:27018258

  14. Piezonuclear reactions - do they exist?

    CERN Document Server

    Ericsson, G; Sjöstrand, H; Traneus, E

    2009-01-01

    In a number of recent articles in this journal F. Cardone and collaborators have claimed the observation of several striking nuclear phenomena which they attribute to "piezonuclear reactions". One such claim [Phys. Lett. A 373 (2009) 1956] is that subjecting a solution of 228Th to cavitation leads to a "transformation" of thorium nuclei that is 104 times faster than the normal nuclear decay for this isotope. In a "Comment" [Phys. Lett. A 373 (2009) 3795] to the thorium work, we have criticized the evidence provided for this claim. In a "Reply" [Phys. Lett. A 373 (2009) 3797] Cardone et al. answer only some minor points but avoid addressing the real issue. The information provided in their Reply displays a worrying lack of control of their experimental situation and the data they put forward as evidence for their claims. We point out several shortcomings and errors in the described experimental preparations, set-up and reporting, as well as in the data analysis. We conclude that the evidence presented by Cardo...

  15. Influences of Reaction Parameters on the Product of a Geothermite Reaction: A Multi-Component Oxidation-Reduction Reaction Study

    OpenAIRE

    Faierson, Eric J.

    2009-01-01

    This study investigated an oxidation-reduction reaction involving a mixture of minerals, glass, and aluminum that exhibited thermite-type reaction behavior. Thermite reactions are a class of Self-propagating High-temperature Synthesis (SHS) reactions. Chemical reactions between raw minerals and a reducing agent, which exhibit thermite-type reaction behavior, are termed geothermite reactions by the author. Geothermite reactions have the potential for use in In-Situ Resource Utilization (ISRU...

  16. [Reaction mechanism studies of heavy ion induced nuclear reactions

    International Nuclear Information System (INIS)

    This report contains papers that discuss: Target Dependence of Complex Fragment Emission in 47-MeV/u La-Induced Reactions; Deconvolution of Time-of-Flight Data to Improve Mass Identification; and Study of the Reaction of La + Al at E/A = 50 MeV with Landau-Vlasov Dynamics

  17. Dynamic Reaction Figures: An Integrative Vehicle for Understanding Chemical Reactions

    Science.gov (United States)

    Schultz, Emeric

    2008-01-01

    A highly flexible learning tool, referred to as a dynamic reaction figure, is described. Application of these figures can (i) yield the correct chemical equation by simply following a set of menu driven directions; (ii) present the underlying "mechanism" in chemical reactions; and (iii) help to solve quantitative problems in a number of different…

  18. Progress in microscopic direct reaction modeling of nucleon induced reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, M.; Bauge, E.; Hilaire, S.; Lechaftois, F.; Peru, S.; Pillet, N.; Robin, C. [CEA, DAM, DIF, Arpajon (France)

    2015-12-15

    A microscopic nuclear reaction model is applied to neutron elastic and direct inelastic scatterings, and pre-equilibrium reaction. The JLM folding model is used with nuclear structure information calculated within the quasi-particle random phase approximation implemented with the Gogny D1S interaction. The folding model for direct inelastic scattering is extended to include rearrangement corrections stemming from both isoscalar and isovector density variations occurring during a transition. The quality of the predicted (n,n), (n,n{sup '}), (n,xn) and (n,n{sup '}γ) cross sections, as well as the generality of the present microscopic approach, shows that it is a powerful tool that can help improving nuclear reactions data quality. Short- and long-term perspectives are drawn to extend the present approach to more systems, to include missing reactions mechanisms, and to consistently treat both structure and reaction problems. (orig.)

  19. Microscopic effective reaction theory for deuteron-induced reactions

    CERN Document Server

    Neoh, Yuen Sim; Minomo, Kosho; Ogata, Kazuyuki

    2016-01-01

    The microscopic effective reaction theory is applied to deuteron-induced reactions. A reaction model-space characterized by a $p+n+{\\rm A}$ three-body model is adopted, where A is the target nucleus, and the nucleon-target potential is described by a microscopic folding model based on an effective nucleon-nucleon interaction in nuclear medium and a one-body nuclear density of A. The three-body scattering wave function in the model space is obtained with the continuum-discretized coupled-channels method (CDCC), and the eikonal reaction theory (ERT), an extension of CDCC, is applied to the calculation of neutron removal cross sections. Elastic scattering cross sections of deuteron on $^{58}$Ni and $^{208}$Pb target nuclei at several energies are compared with experimental data. The total reaction cross sections and the neutron removal cross sections at 56 MeV on 14 target nuclei are calculated and compared with experimental values.

  20. Dynamics of fission and heavy ion reactions

    International Nuclear Information System (INIS)

    Recent advances in a unified macroscopic-microscopic description of large-amplitude collective nuclear motion such as occurs in fission and heavy ion reactions are discussed. With the goal of finding observable quantities that depend upon the magnitude and mechanism of nuclear dissipation, one-body dissipation and two-body viscosity within the framework of a generalized Fokker-Planck equation for the time dependence of the distribution function in phase space of collective coordinates and momenta are considered. Proceeding in two separate directions, the generalized Hamilton equations of motion for the first moments of the distribution function with a new shape parametrization and other technical innovations are first solved. This yields the mean translational fission-fragment kinetic energy and mass of a third fragment that sometimes forms between the two end fragments, as well as the energy required for fusion in symmetric heavy-ion reactions and the mass transfer and capture cross section in asymmetric heavy-ion reactions. In a second direction, we specialize to an inverted-oscillator fission barrier and use Kramers' stationary solution to calculate the mean time from the saddle point to scission for a heavy-ion-induced fission reaction for which experimental information is becoming available. 25 references

  1. Serum tryptase levels in adverse drug reactions.

    Science.gov (United States)

    Ordoqui, E; Zubeldia, J M; Aranzábal, A; Rubio, M; Herrero, T; Tornero, P; Rodríguez, V M; Prieto, A; Baeza, M L

    1997-11-01

    We evaluated the usefulness of individual tryptase levels and variations after adverse drug reactions in 64 patients. Our aim was to find a tool for the diagnosis of drug allergy. Thirty-seven subjects were confirmed to have drug allergy, 12 had nonsteroidal anti-inflammatory drug (NSAID) reactions, five had negative controlled drug challenges (NAAR), and 10 had symptoms after placebo intake (PLA). Serum tryptase levels greatly increased after anaphylactic shocks (2242%) and anaphylaxis (710.5%). Patients with allergic urticaria and those with idiosyncratic responses to acetylsalicylic acid (ASA) exhibited a small increase in serum tryptase (49.5% and 38.2%, respectively). In the other two groups (NAAR and PLA), no variation in this serum protease was observed. The time of appearance of the serum tryptase peak differed considerably among patients with similar clinical reactions (from 30 min to 6 h) and was independent of the latent period, severity of symptoms, or the amount of tryptase released. We conclude that serum tryptase determinations are helpful in the diagnosis of anaphylactic shock and anaphylaxis, but serial measurements may be needed to confirm mast-cell participation in milder reactions.

  2. Observation of HONO in Changzhou

    Science.gov (United States)

    Hou, Yanping; Chen, Jun; Lou, Shengrong

    2016-04-01

    Gaseous nitrous acid (HONO) is one of the sources of atmospheric hydroxyl radicals, which has an important influence on the increase of atmospheric oxidation. In addition to the first emission and the homogeneous reaction of OH+NO in the gas phase, the heterogeneous reaction of NO2 on various surfaces is considered to be the source of HONO. During the period of observation in the Yangtze River Delta on June 2015, we apply the LOng Path Absorption Photometer (LOPAP) to measure the HONO concentration at Changzhou site. With the information of NOX, aerosol physics, properties and meteorological conditions obtained from the same period, we analyzed the source of HONO at night. In the case of June 4th, 5th, and 15th at night, the concentration of HONO reached the highest value during the observation period ~3.0 ppb. Except for these three days, HONO mean concentration generally in about 1-2 ppb, the HONO/NO2 range during the period of observation is 0.32%~10.9%, within the domestic and foreign observation in the clean zone values, the average of values is 4.23%, within the general scope of 0.5% ~ 5%. The results between HONO concentration and PM10 and PM2.5 at night show uncorrelated coefficient of R=0.186 and R=0.2108 respectively. The source apportionment showed high contribution from local combustion process of fossil fuels during the observation period and the heterogeneous reaction on the surface of the aerosol at night needs further study.

  3. Astronomy with Radioactivities: Chapter 9, Nuclear Reactions

    OpenAIRE

    Wiescher, M.; Rauscher, T.

    2010-01-01

    Nuclear reaction rates determine the abundances of isotopes in stellar burning processes. A multitude of reactions determine the reaction flow pattern which is described in terms of reaction network simulations. The reaction rates are determined by laboratory experiments supplemented by nuclear reaction and structure theory. We will discuss the experimental approach as well as the theoretical tools for obtaining the stellar reaction rates. A detailed analysis of a reaction is only possible fo...

  4. Performance of Lightweight Concrete based on Granulated Foamglass

    Science.gov (United States)

    Popov, M.; Zakrevskaya, L.; Vaganov, V.; Hempel, S.; Mechtcherine, V.

    2015-11-01

    The paper presents an investigation of lightweight concretes properties, based on granulated foamglass (GFG-LWC) aggregates. The application of granulated foamglass (GFG) in concrete might significantly reduce the volume of waste glass and enhance the recycling industry in order to improve environmental performance. The conducted experiments showed high strength and thermal properties for GFG-LWC. However, the use of GFG in concrete is associated with the risk of harmful alkali-silica reactions (ASR). Thus, one of the main aims was to study ASR manifestation in GFG-LWC. It was found that the lightweight concrete based on porous aggregates, and ordinary concrete, have different a mechanism of ASR. In GFG-LWC, microstructural changes, partial destruction of granules, and accumulation of silica hydro-gel in pores were observed. According to the existing methods of analysis of ASR manifestation in concrete, sample expansion was measured, however, this method was found to be not appropriate to indicate ASR in concrete with porous aggregates. Microstructural analysis and testing of the concrete strength are needed to evaluate the damage degree due to ASR. Low-alkali cement and various pozzolanic additives as preventive measures against ASR were chosen. The final composition of the GFG-LWC provides very good characteristics with respect to compressive strength, thermal conductivity and durability. On the whole, the potential for GFG-LWC has been identified.

  5. Application of Image Analysis to Identify Quartz Grains in Heavy Aggregates Susceptible to ASR in Radiation Shielding Concrete

    Directory of Open Access Journals (Sweden)

    Daria Jóźwiak-Niedźwiedzka

    2016-03-01

    Full Text Available Alkali-silica reaction (ASR is considered as a potential aging-related degradation phenomenon that might impair the durability of concrete in nuclear containments. The objective of this paper is the application of digital analysis of microscopic images to identify the content and size of quartz grains in heavy mineral aggregates. The range of investigation covered magnetite and hematite aggregates, known as good absorbers of gamma radiation. Image acquisition was performed using thin sections observed in transmitted cross-polarized light with λ plate. Image processing, consisting of identification of ferrum oxide and epoxy resin, and the subsequent application of a set of filtering operations resulted in an adequate image reduction allowing the grain size analysis. Quartz grains were classified according to their mean diameter so as to identify the reactive range. Accelerated mortar bar tests were performed to evaluate the ASR potential of the aggregates. The SiO2 content in the heavyweight aggregates determined using the image analysis of thin sections was similar to XRF test result. The content of reactive quartz hematite was 2.7%, suggesting that it would be prone to ASR. The expansion test, according to ASTM C1260, confirmed the prediction obtained using the digital image analysis.

  6. Matrix isolation as a tool for studying interstellar chemical reactions

    Science.gov (United States)

    Ball, David W.; Ortman, Bryan J.; Hauge, Robert H.; Margrave, John L.

    1989-01-01

    Since the identification of the OH radical as an interstellar species, over 50 molecular species were identified as interstellar denizens. While identification of new species appears straightforward, an explanation for their mechanisms of formation is not. Most astronomers concede that large bodies like interstellar dust grains are necessary for adsorption of molecules and their energies of reactions, but many of the mechanistic steps are unknown and speculative. It is proposed that data from matrix isolation experiments involving the reactions of refractory materials (especially C, Si, and Fe atoms and clusters) with small molecules (mainly H2, H2O, CO, CO2) are particularly applicable to explaining mechanistic details of likely interstellar chemical reactions. In many cases, matrix isolation techniques are the sole method of studying such reactions; also in many cases, complexations and bond rearrangements yield molecules never before observed. The study of these reactions thus provides a logical basis for the mechanisms of interstellar reactions. A list of reactions is presented that would simulate interstellar chemical reactions. These reactions were studied using FTIR-matrix isolation techniques.

  7. Chemistry of heavy ion reactions

    International Nuclear Information System (INIS)

    The use of heavy ions to induce nuclear reactions was reported as early as 1950. Since that time it has been one of the most active areas of nuclear research. Intense beams of ions as heavy as uranium with energies high enough to overcome the Coulomb barriers of even the heaviest elements are available. The wide variety of possible reactions gives rise to a multitude of products which have been studied by many ingenious chemical and physical techniques. Chemical techniques have been of special value for the separation and unequivocal identification of low yield species from the plethora of other nuclides present. Heavy ion reactions have been essential for the production of the trans-Md elements and a host of new isotopes. The systematics of compound nucleus reactions, transfer reactions, and deeply inelastic reactions have been elucidated using chemical techniques. A review of the variety of chemical procedures and techniques which have been developed for the study of heavy ion reactions and their products is given. Determination of the chemical properties of the trans-Md elements, which are very short-lived and can only be produced an ''atom-at-a-time'' via heavy ion reactions, is discussed. 53 refs., 19 figs

  8. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  9. Zeolite Catalyzed Aldol Condensation Reactions

    Directory of Open Access Journals (Sweden)

    Adedayo I. Inegbenebor

    2015-03-01

    Full Text Available The review is based on the description of zeolite structure, uses, synthesis, and catalytic aldol reaction in aldol condensation. An internal aldolcondensation reaction has been achieved over ZSM-5 zeolite with high silica-alumina ratio at 350oC. It therefore follows that zeolite canfunction as a catalyst in aldol type condensation reactions and that weak acid sites as well as a small number of active sites favor the aldolcondensation reaction of carbonyl compounds. However, the mixed condensation product was found to be favored at temperatures above 300oCand the self-condensation of ethanal to crotonaldehyde was favored at temperatures below 300oC. It has also been suggested that both Brønstedand Lewis acids are involved in aldol reactions with Lewis acid sites the most probable catalytic sites. The zeolite group of minerals has founduse in many chemical and allied industries.

  10. Effective reaction rates for diffusion-limited reaction cycles

    Science.gov (United States)

    Nałecz-Jawecki, Paweł; Szymańska, Paulina; Kochańczyk, Marek; Miekisz, Jacek; Lipniacki, Tomasz

    2015-12-01

    Biological signals in cells are transmitted with the use of reaction cycles, such as the phosphorylation-dephosphorylation cycle, in which substrate is modified by antagonistic enzymes. An appreciable share of such reactions takes place in crowded environments of two-dimensional structures, such as plasma membrane or intracellular membranes, and is expected to be diffusion-controlled. In this work, starting from the microscopic bimolecular reaction rate constants and using estimates of the mean first-passage time for an enzyme-substrate encounter, we derive diffusion-dependent effective macroscopic reaction rate coefficients (EMRRC) for a generic reaction cycle. Each EMRRC was found to be half of the harmonic average of the microscopic rate constant (phosphorylation c or dephosphorylation d), and the effective (crowding-dependent) motility divided by a slowly decreasing logarithmic function of the sum of the enzyme concentrations. This implies that when c and d differ, the two EMRRCs scale differently with the motility, rendering the steady-state fraction of phosphorylated substrate molecules diffusion-dependent. Analytical predictions are verified using kinetic Monte Carlo simulations on the two-dimensional triangular lattice at the single-molecule resolution. It is demonstrated that the proposed formulas estimate the steady-state concentrations and effective reaction rates for different sets of microscopic reaction rates and concentrations of reactants, including a non-trivial example where with increasing diffusivity the fraction of phosphorylated substrate molecules changes from 10% to 90%.

  11. Eikonal reaction theory for two-neutron removal reactions

    CERN Document Server

    Minomo, K; Egashira, K; Ogata, K; Yahiro, M

    2014-01-01

    The eikonal reaction theory (ERT) proposed lately is a method of calculating one-neutron removal reactions at intermediate incident energies in which Coulomb breakup is treated accurately with the continuum discretized coupled-channels method. ERT is extended to two-neutron removal reactions. ERT reproduces measured one- and two-neutron removal cross sections for 6He scattering on 12C and 208Pb targets at 240 MeV/nucleon and also on a 28Si target at 52 MeV/nucleon. For the heavier target in which Coulomb breakup is important, ERT yields much better agreement with the measured cross sections than the Glauber model.

  12. Neck fragmentation reaction mechanism

    CERN Document Server

    Baran, V; Di Toro, M

    2004-01-01

    Based on a microscopic transport model, we study the origin of nonstatistical Intermediate Mass Fragment ($IMF$) production in semicentral heavy ion collisions at the Fermi energies. We show that a fast, dynamical $IMF$ formation process, the {\\it neck fragmentation mechanism}, can explain the experimentally observed features: deviations from Viola systematics and anisotropic, narrow angular distributions. It may be regarded as the continuation of the multifragmentation mechanism towards intermediate impact parameters. Its relation to other dynamical mechanisms, the induced fission and the abrasion of the spectator zones, that can also contribute to mid-rapidity $IMF$ production, is discussed. The dependence on beam energy and centrality of the collision is carefully analysed. The competition between volume and surface instabilities makes this mechanism very sensitive to the in-medium nucleon-nucleon interactions, from the cross sections for hard collisions to the compressibility and other Equation of State (...

  13. Light particle revelation on incomplete fusion reactions

    International Nuclear Information System (INIS)

    Incomplete fusion reactions have been studied through light particles emission in the reaction 116Sn + 16O at 125 MeV (ALICE facility in Orsay). We measured energy angular distributions and correlations between any two of these particles (α particles, protons, neutrons), while γ multiplicity measurements provide us fuller informations. From collected data, the following pictures can be drawn: - the only fast particles observed are α particles, while protons and neutrons seem to come only from statistical evaporation; - outgoing channels where two α particles are emitted cannot be solely explained by the sequential emission of 8Be → 2α: about half of the cross section proceeds from statistical evaporation of one α particle. Accordingly, 2αxn channels do not necessarily agree with high value of angular momentum in the entrance channel. From the study of experimental results in the yrast plane, we can assign a large width to the angular momentum distribution

  14. A review of tritium conversion reactions

    International Nuclear Information System (INIS)

    The chemical processes by which elemental tritium can be converted to tritiated water have been examined by reviewing the available literature on these processes. It would appear that gas phase conversion reactions at room temperature are slow and that they do not contribute significantly to any observed conversion following releases of elemental tritium. The effects of surfaces are not clearly understood. Metals, however, can increase the rate over the gas phase processes, but the magnitude of this increase is not well documented. Further work is necessary to examine the effects of various materials, elevated temperatures, and other parameters on conversion reactions in order to more closely reflect conditions in reactor buildings and other tritium containing facilities

  15. Transfer reaction code with nonlocal interactions

    CERN Document Server

    Titus, L J; Nunes, F M

    2016-01-01

    We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, $(d,N)$ or $(N,d)$, including nonlocal nucleon-target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of $A(d,N)B$ or $B(N,d)A$. Details on the implementation of the T-matrix to obtain the final cross sections within the adiabatic distorted wave approximation method are also provided. This code is suitable to be applied for deuteron induced reactions in the range of $E_d=10-70$ MeV, and provides cross sections with $4\\%$ accuracy.

  16. Transfer reaction code with nonlocal interactions

    Science.gov (United States)

    Titus, L. J.; Ross, A.; Nunes, F. M.

    2016-10-01

    We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, (d , N) or (N , d) , including nonlocal nucleon-target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of A(d , N) B or B(N , d) A. Details on the implementation of the T-matrix to obtain the final cross sections within the adiabatic distorted wave approximation method are also provided. This code is suitable to be applied for deuteron induced reactions in the range of Ed =10-70 MeV, and provides cross sections with 4% accuracy.

  17. Reaction kinetics of bond rotations in graphene

    KAUST Repository

    Skowron, Stephen T.

    2016-04-12

    The formation and healing processes of the fundamental topological defect in graphitic materials, the Stone-Wales (SW) defect, are brought into a chemical context by considering the rotation of a carbon-carbon bond as chemical reaction. We investigate the rates and mechanisms of these SW transformations in graphene at the atomic scale using transmission electron microscopy. We develop a statistical atomic kinetics formalism, using direct observations obtained under different conditions to determine key kinetic parameters of the reactions. Based on the obtained statistics we quantify thermally and irradiation induced routes, identifying a thermal process of healing with an activation energy consistent with predicted adatom catalysed mechanisms. We discover exceptionally high rates for irradiation induced SW healing, incompatible with the previously assumed mechanism of direct knock-on damage and indicating the presence of an efficient nonadiabatic coupling healing mechanism involving beam induced electronic excitations of the SW defect.

  18. Asymmetric Michael Reaction of Malononitrile Catalyzed by Chiral Ru(Ⅱ) Complex and Achiral Base

    Institute of Scientific and Technical Information of China (English)

    MA Ya-Ping; XING Zhi-Kui; ZHU Jin; CUI Xin; CUN Lin-Feng; DENG Jin-Gen

    2003-01-01

    @@ Michael addition reactions represent one of the most important carbon-carbon bond forming reactions in modern synthetic organic chemistry. [1 ~3] We achieved catalytic enantioselective Michael addition reactions of malononitrile with chiral vicinal diamine-Ru(Ⅱ) complex in the presence of achiral base. High yields and moderate ee were observed.

  19. The 'compensation effect' in the graphite/CO2 reaction

    International Nuclear Information System (INIS)

    The compensation effect is the often observed linear relationship between the activation energy and pre-exponential factor in the Arrhenius equations of a series of related reactions. Previously reported studies of the graphite/CO2 reaction at different total pressures and CO2/CO ratios are used as an example of the compensation effect. The effect is shown in general to be an artefact produced by a strong correlation between the parameter estimates in the conventional Arrhenius plot. A transformation of the Arrhenius plot to minimise the overall correlation between estimates and thus enable detection of a true compensation effect is presented. The results of this transformation on the kinetic data for the graphite/CO2 reaction are consistent with previous analyses of the reaction system. They show that there is only a limited compensation effect within this study and demonstrate the influence of the approach to equilibrium of the graphite/CO2 reaction. (author)

  20. Fundamental studies of retrograde reactions in direct liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S.; Bassilakis, R.

    1991-12-17

    The overall objective of the program was to improve the understanding of retrograde reactions and their dependencies on coal rank and structure, and/or coal modifications and reaction conditions. Because retrograde reactions are competitive with bond breaking reactions, an understanding of both is required to shift the competition in favor of the latter. Related objectives were to clarify the conflicting observations reported in literature on such major topics as the role of oxygen groups in retrograde reactions and to provide a bridge from very fundamental studies on pure compounds to phenomenological studies on actual coal. This information was integrated into the FG-DVC model, which was improved and extended to the liquefaction context.

  1. Dynamics of synchrotron VUV-induced intracluster reactions

    Energy Technology Data Exchange (ETDEWEB)

    Grover, J.R. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    Photoionization mass spectrometry (PIMS) using the tunable vacuum ultraviolet radiation available at the National Synchrotron Light Source is being exploited to study photoionization-induced reactions in small van der Waals mixed complexes. The information gained includes the observation and classification of reaction paths, the measurement of onsets, and the determination of relative yields of competing reactions. Additional information is obtained by comparison of the properties of different reacting systems. Special attention is given to finding unexpected features, and most of the reactions investigated to date display such features. However, understanding these reactions demands dynamical information, in addition to what is provided by PIMS. Therefore the program has been expanded to include the measurement of kinetic energy release distributions.

  2. Quantum effects in unimolecular reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gezelter, J.D.

    1995-12-01

    This work is primarily concerned with the development of models for the quantum dynamics of unimolecular isomerization and photodissociation reactions. We apply the rigorous quantum methodology of a Discrete Variable Representation (DVR) with Absorbing Boundary Conditions (ABC) to these models in an attempt to explain some very surprising results from a series of experiments on vibrationally excited ketene. Within the framework of these models, we are able to identify the experimental signatures of tunneling and dynamical resonances in the energy dependence of the rate of ketene isomerization. Additionally, we investigate the step-like features in the energy dependence of the rate of dissociation of triplet ketene to form {sup 3}B{sub 1} CH{sub 2} + {sup 1}{sigma}{sup +} CO that have been observed experimentally. These calculations provide a link between ab initio calculations of the potential energy surfaces and the experimentally observed dynamics on these surfaces. Additionally, we develop an approximate model for the partitioning of energy in the products of photodissociation reactions of large molecules with appreciable barriers to recombination. In simple bond cleavage reactions like CH{sub 3}COCl {yields} CH{sub 3}CO + Cl, the model does considerably better than other impulsive and statistical models in predicting the energy distribution in the products. We also investigate ways of correcting classical mechanics to include the important quantum mechanical aspects of zero-point energy. The method we investigate is found to introduce a number of undesirable dynamical artifacts including a reduction in the above-threshold rates for simple reactions, and a strong mixing of the chaotic and regular energy domains for some model problems. We conclude by discussing some of the directions for future research in the field of theoretical chemical dynamics.

  3. Integrated Microreactors for Reaction Automation: New Approaches to Reaction Development

    Science.gov (United States)

    McMullen, Jonathan P.; Jensen, Klavs F.

    2010-07-01

    Applications of microsystems (microreactors) in continuous-flow chemistry have expanded rapidly over the past two decades, with numerous reports of higher conversions and yields compared to conventional batch benchtop equipment. Synthesis applications are enhanced by chemical information gained from integrating microreactor components with sensors, actuators, and automated fluid handling. Moreover, miniaturized systems allow experiments on well-defined samples at conditions not easily accessed by conventional means, such as reactions at high pressure and temperatures. The wealth of synthesis information that could potentially be acquired through use of microreactors integrated with physical sensors and analytical chemistry techniques for online reaction monitoring has not yet been well explored. The increased efficiency resulting from use of continuous-flow microreactor platforms to automate reaction screening and optimization encourages a shift from current batchwise chemical reaction development to this new approach. We review advances in this new area and provide application examples of online monitoring and automation.

  4. Thin film reactions on alloy semiconductor substrates

    Energy Technology Data Exchange (ETDEWEB)

    Olson, D.A.

    1990-11-01

    The interactions between Pt and In{sub .53}Ga{sub .47}As have been studied. In{sub .53}Ga{sub .47}As substrates with 70nm Pt films were encapsulated in SiO{sub 2}, and annealed up to 600{degree}C in flowing forming gas. The composition and morphology of the reaction product phases were studied using x-ray diffraction, Auger depth profiling, and transmission electron microscopy. The reaction kinetics were examined with Rutherford Backscattering. Results show that Pt/In{sub .53}Ga{sub .47}As reacts to form many of the reaction products encountered in the Pt/GaAs and Pt/InP reactions: PtGa, Pt{sub 3}Ga, and PtAs{sub 2}. In addition, a ternary phase, Pt(In:Ga){sub 2}, develops, which is a solid solution between PtIn{sub 2} and PtGa{sub 2}. The amount of Ga in the ternary phase increases with annealing temperature, which causes a decrease in the lattice parameter of the phase. The reaction products show a tendency to form layered structures, especially for higher temperatures and longer annealing times. Unlike the binary case, the PtAs{sub 2}, phase is randomly oriented on the substrate, and is intermingle with a significant amount of Pt(In:Ga){sub 2}. Following Pt/In{sub .53}Ga{sub .47}As reactions, two orientation relationships between the Pt(In:Ga){sub 2} product phase and the substrate were observed, despite the large mismatch with the substrate ({approximately}8%). For many metal/compound semiconductor interactions, the reaction rate is diffusion limited, i.e. exhibits a parabolic dependence on time. An additional result of this study was the development of an In-rich layer beneath the reacted layer. The Auger depth profile showed a substantial increase in the sample at this layer. This is a significant result for the production of ohmic contacts, as the Schottky barrier height in this system lower for higher In concentrations. 216 refs.

  5. Reaction dynamics and photochemistry of divalent systems

    Energy Technology Data Exchange (ETDEWEB)

    Davis, H.F.

    1992-05-01

    Results are presented of molecular beam studies of bimolecular and unimolecular reactions of Ba. Chapter 1 discusses the reaction Ba + NO{sub 2}. Formation of the dominant BaO({sup 1}{Sigma}) + NO products resulted primarily from decay of long-lived Ba{sup +}NO{sub 2}{sup {minus}} collision complexes. Secondary mechanisms led to formation of forward scattered, internally excited BaO, and BaNO + O. D{sub o}(Ba-NO) = 65{plus_minus}20 kcal/mol. Reactions of ground state and electronically excited Ba with water and alcohols are examined in Chapter 2. Reaction of Ba({sup 1}S) + H{sup 2}O led to BaO + H{sub 2}, whereas excited state Ba({sup 1}D) + H{sub 2}O reacted to form BaOH + H. Collisions between Ba and CH{sub 3}OH led to BaOCH{sub 3} + H. Radical channels involve H-atom migration and are promoted by excitation of the incident Ba atom. In Chapter 3, reactions of Ba({sup 1}S) with ClO{sub 2}2 and O{sub 3} are discussed. Again, direct and complex mechanisms were observed. Formation of BaCl + O{sub 2} from decomposition of Ba{sup +}ClO{sub 2}{sup {minus}} accounted for 10% of total reaction crass section. Although Ba + O{sub 3} {yields} BaO + 0{sub 2} occurs primarily by direct reaction mechanisms, the secondary channel Ba + 0{sub 3} {yields} BaO{sub 2} + 0 involved decay of long lived Ba{sup +}O{sub 3}{sup {minus}} intermediates. D{sub o}(Ba{minus}O{sub 2}) = 120 {plus_minus}20 kcal/mol. Photodissociation dynamics of NO{sub 3} is explored in chapter 4. Visible excitation leads to formation of NO + 0{sub 2} and NO{sub 2} + O. Wavelength dependence of branching ratios is investigated. D{sub o}(O-NO{sub 2}) = 48.55 kcal/mole ;and calculate {Delta}H{sub f}(NO{sub 3}) = 17.75 kcal/mole (298K). Chapter 5 discusses the photodissociation of OClO in a molecular beam. Although ClO({sup 2}II) + O({sup 3}P) is dominant, Cl({sup 2}P) + O{sub 2} also forms, with a max yield of 3.9{plus_minus}0.8% near 404nm.

  6. Drug hypersensitivity reactions involving skin.

    Science.gov (United States)

    Hausmann, Oliver; Schnyder, Benno; Pichler, Werner J

    2010-01-01

    Immune reactions to drugs can cause a variety of diseases involving the skin, liver, kidney, lungs, and other organs. Beside immediate, IgE-mediated reactions of varying degrees (urticaria to anaphylactic shock), many drug hypersensitivity reactions appear delayed, namely hours to days after starting drug treatment, showing a variety of clinical manifestations from solely skin involvement to fulminant systemic diseases which may be fatal. Immunohistochemical and functional studies of drug-specific T cells in patients with delayed reactions confirmed a predominant role for T cells in the onset and maintenance of immune-mediated delayed drug hypersensitivity reactions (type IV reactions). In these reactions, drug-specific CD4+ and CD8+ T cells are stimulated by drugs through their T cell receptors (TCR). Drugs can stimulate T cells in two ways: they can act as haptens and bind covalently to larger protein structures (hapten-carrier model), inducing a specific immune response. In addition, they may accidentally bind in a labile, noncovalent way to a particular TCR of the whole TCR repertoire and possibly also major histocompatibility complex (MHC)-molecules - similar to their pharmacologic action. This seems to be sufficient to reactivate certain, probably in vivo preactivated T cells, if an additional interaction of the drug-stimulated TCR with MHC molecules occurs. The mechanism was named pharmacological interaction of a drug with (immune) receptor and thus termed the p-i concept. This new concept may explain the frequent skin symptoms in drug hypersensitivity to oral or parenteral drugs. Furthermore, the various clinical manifestations of T cell-mediated drug hypersensitivity may be explained by distinct T cell functions leading to different clinical phenotypes. These data allowed a subclassification of the delayed hypersensitivity reactions (type IV) into T cell reactions which, by releasing certain cytokines and chemokines, preferentially activate and recruit

  7. [Food hypersensibility: inhalation reactions are different from ingestion reactions].

    Science.gov (United States)

    Baranes, T; Bidat, E

    2008-06-01

    Eight children, aged from 3 to 9 years, presented to inhaled peanut an immediate allergic reaction. All were sensitized to peanut but none had already ingested it overtly. A strict avoidance diet was prescribed concerning this food allergen. An oral provocation challenge was realized to determine the eliciting dose (ED) to ingestion. The ED was high enough to allow all the children a less restrictive diet. Inhaled allergic reaction to peanut does not always justify a strict avoidance diet. PMID:18456474

  8. Enhancement of Sonochemical Reaction by Dual-Pulse Ultrasound

    Science.gov (United States)

    Xu, Zheng; Yasuda, Keiji

    2011-07-01

    In order to apply sonochemistry in wastewater treatment, enhancement of sonochemical reaction is necessary. Oxidation of potassium iodide and the degradation of acid orange 7 in aqueous solution using ultrasound irradiation were performed at 490 kHz. Power-modulated pulsed waves were employed and the enhancement of reaction amount was observed compared with using continuous wave. The enhancement ratio for irradiation to rigid wall was larger than that for irradiation to free surface. Moreover, the best modulated pulsed on time was experimentally determined and the effect of the superposition of pulsed waves (dual-pulse) was studied. Enhancement was also observed and calculated separately when using dual-pulse ultrasound. The enhancement upon the use of the dual-transducer was ascribed to the enlargement of sonochemical reaction field. The enhancement upon the incorporating pulsed waves was ascribed to both the reduction of reaction threshold effect and the residual acoustical pressure at the pulsed off time.

  9. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

    Full Text Available Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination.

  10. Time-Dependent Quantum Dynamics of T+CH4 → CH3+HT Reaction

    Institute of Scientific and Technical Information of China (English)

    BAI Li-Hua; ZHANG Jing-Tao; ZHANG Qing-Gang; XU Zhi-Zhan

    2004-01-01

    @@ Reaction probability, cross section and rate constant are studied for polyatomic reaction T+CH4 → CHs+HT using the semirigid vibrating rotor target (SVRT) model. The numerical calculation for the reaction system is carried out using the time-dependent wavepacket method, and the wavepacket is propagated by the splitoperator method. The calculation exhibits a variety of features that can be used for comparison with future experimental investigations. The reaction probability as a function of the translational energy shows slight oscillatory structures, similar to those observed in H abstraction reactions H+H2 and H+CH4. The comparisons with the H+CH4 reaction are described.

  11. Palladium-catalyzed coupling reactions

    CERN Document Server

    Molnár, Árpád

    2013-01-01

    This handbook and ready reference brings together all significant issues of practical importance for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of modern-day coupling reactions and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With i

  12. Chemical potential and reaction electronic flux in symmetry controlled reactions.

    Science.gov (United States)

    Vogt-Geisse, Stefan; Toro-Labbé, Alejandro

    2016-07-15

    In symmetry controlled reactions, orbital degeneracies among orbitals of different symmetries can occur along a reaction coordinate. In such case Koopmans' theorem and the finite difference approximation provide a chemical potential profile with nondifferentiable points. This results in an ill-defined reaction electronic flux (REF) profile, since it is defined as the derivative of the chemical potential with respect to the reaction coordinate. To overcome this deficiency, we propose a new way for the calculation of the chemical potential based on a many orbital approach, suitable for reactions in which symmetry is preserved. This new approach gives rise to a new descriptor: symmetry adapted chemical potential (SA-CP), which is the chemical potential corresponding to a given irreducible representation of a symmetry group. A corresponding symmetry adapted reaction electronic flux (SA-REF) is also obtained. Using this approach smooth chemical potential profiles and well defined REFs are achieved. An application of SA-CP and SA-REF is presented by studying the Cs enol-keto tautomerization of thioformic acid. Two SA-REFs are obtained, JA'(ξ) and JA'' (ξ). It is found that the tautomerization proceeds via an in-plane delocalized 3-center 4-electron O-H-S hypervalent bond which is predicted to exist only in the transition state (TS) region. © 2016 Wiley Periodicals, Inc.

  13. Anisotropic Inflation and Cosmological Observations

    CERN Document Server

    Emami, Razieh

    2015-01-01

    Recent observations opened up a new window on the inflationary model building. As it was firstly reported by the WMAP data, there may be some indications of statistical anisotropy on the CMB map, although the statistical significance of these findings are under debate. Motivated by these observations, people begun considering new inflationary models which may lead to statistical anisotropy. The simplest possible way to construct anisotropic inflation is to introduce vector fields. During the course of this thesis, we study models of anisotropic inflation and their observational implications such as power spectrum, bispectrum etc. Firstly we build a new model, which contains the gauge field which breaks the conformal invariance while preserving the gauge invariance. We show that in these kind of models, there can be an attractor phase in the evolution of the system when the back-reaction of the gauge field becomes important in the evolution of the inflaton field. We then study the cosmological perturbation the...

  14. Statistical properties of multistep enzyme-mediated reactions

    OpenAIRE

    de Ronde, Wiet H.; Daniels, Bryan C.; Mugler, Andrew; Sinitsyn, Nikolai A.; Nemenman, Ilya

    2008-01-01

    Enzyme-mediated reactions may proceed through multiple intermediate conformational states before creating a final product molecule, and one often wishes to identify such intermediate structures from observations of the product creation. In this paper, we address this problem by solving the chemical master equations for various enzymatic reactions. We devise a perturbation theory analogous to that used in quantum mechanics that allows us to determine the first () and the second (variance) cumu...

  15. Pre-equilibrium decay processes in energetic heavy ion reactions

    International Nuclear Information System (INIS)

    The Boltzmann master equation (BME) is defined for application to precompound decay in heavy ion reactions in the 10 100 MeV/nucleon regime. Predicted neutron spectra are compared with measured results for central collisions of 20Ne and 12C with 165Ho target nuclei. Comparisons are made with subthreshold π0 yields in heavy ion reactions between 35 and 84 MeV/nucleon, and with the π0 spectra. The BME is found to be an excellent tool for investigating these experimentally observed aspects of non-equilibrium heavy ion reactions. 18 refs., 8 figs

  16. Theoretical study on the reaction of VS+(3∑-, 1Γ) with CO

    Institute of Scientific and Technical Information of China (English)

    Shi Wen Yu; Li Qing Yin; Li Feng Yao; Ming Li; Xiao Guang Xie

    2008-01-01

    Two possible reaction mechanisms of VS+(3Ε-, 1Γ) with CO in the gas phase have been studied by using B3LYP/TZVP and CCSD(T)/6-311+G (3df, 3pd) methods: the O/S exchange reaction (VS+ + CO → VO+ + CS) and the S-transfer reaction (VS+ + CO → V+ + COS). The two reactions proceed via two-step and one-step mechanism, respectively. The barriers of the triplet and singlet PESs are 30.6 and 50.9 kcal/mol, respectively, for O/S exchange reaction and 7.3 and 50.2 kcal/mol, respectively, for the S-transfer reaction. The results indicate that the triplet ground state reaction is more favorable, and the S-transfer reaction is more favorable than the O/S exchange reaction, which is in good agreement with the experimental observation.

  17. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  18. Legendre Analysis of Hadronic Reactions

    CERN Document Server

    Azimov, Ya I

    2016-01-01

    Expansions over Legendre functions are suggested as a model-independent way of compact presentation of modern precise and high-statistics data for two-hadron reactions. Some properties of the expansions are described.

  19. Statistical emission in nuclear reactions

    International Nuclear Information System (INIS)

    Statistical model in nuclear reactions has been extensively developed in the past decades, mainly by V. Weisskopf. However, a clear understanding of the experimental situation regarding low- and medium- energy nuclear reaction is not yet settled. The interpretation is complicated by the fact that often the reactions proceed via other mechanisms, for instance direct effects. The purpose 'of the present paper is to show how a great number of experiments can be put in agreement with the statistical formulas, and particularly the resonance measurements for slow neutrons, the evaporation spectra from medium-energy (n, n'), (p, n) and (n, p) reactions and the (n, p) cross-sections at 14 MeV. From the set of experiments discussed it is possible to obtain a consistent table of a, the parameter of the level density formula. (author)

  20. Color Changes Mark Polymer Reactions.

    Science.gov (United States)

    Krieger, James H.

    1980-01-01

    Describes how polydiacetylenes can be used as educational aids. These polymers have conjugated backbones, which cause changes in color when the polydiacetylenes undergo various chemical and physical processes. Diagrams summarize all chemical reactions and their associated color changes. (CS)

  1. Transfer reactions in nuclear astrophysics

    Science.gov (United States)

    Bardayan, D. W.

    2016-08-01

    To a high degree many aspects of the large-scale behavior of objects in the Universe are governed by the underlying nuclear physics. In fact the shell structure of nuclear physics is directly imprinted into the chemical abundances of the elements. The tranquility of the night sky is a direct result of the relatively slow rate of nuclear reactions that control and determines a star’s fate. Understanding the nuclear structure and reaction rates between nuclei is vital to understanding our Universe. Nuclear-transfer reactions make accessible a wealth of knowledge from which we can extract much of the required nuclear physics information. A review of transfer reactions for nuclear astrophysics is presented with an emphasis on the experimental challenges and opportunities for future development.

  2. Feedback in Flow for Accelerated Reaction Development.

    Science.gov (United States)

    Reizman, Brandon J; Jensen, Klavs F

    2016-09-20

    microfluidics. This Account details the system configuration for on-demand creation of sub-20 μL droplets with interchangeable reagents and catalysts. These droplets are reacted in a fully automated microfluidic system and analyzed online by LC/MS. Feeding back from the online analytical results, a design of experiments (DoE)-based adaptive response surface algorithm is employed that deductively removes candidate reagents from the optimization as optimal reaction conditions are refined, leading to rapid convergence. Using the automated optimization platform, case studies are presented for solvent selection in a competitive alkylation chemistry and for catalyst-ligand selection in heteroaromatic Suzuki-Miyaura cross-coupling chemistries. For the monoalkylation of trans-1,2-diaminocyclohexane, polar aprotic solvents at moderate temperatures are shown to be favorable, with optimality accurately identified with dimethyl sulfoxide as the solvent in 67 experiments. For Suzuki-Miyaura cross-couplings, the optimality of precatalysts and continuous variable conditions are observed to change in accordance with the coupling reagents, providing insights into catalyst behavior in the context of the reaction mechanism. Future opportunities in automated reaction development include the incorporation of chemoinformatics for faster analysis and machine-learning algorithms to guide and optimize the synthesis. Adoption of this technology stands to reduce graduate student and postdoc time on routine tasks in the laboratory, while feeding back knowledge used to guide new research directions. Moreover, the application of this technology in industry promises to lessen the cost and time associated with advancing pharmaceutical molecules through development and scale-up. PMID:27525813

  3. Feedback in Flow for Accelerated Reaction Development.

    Science.gov (United States)

    Reizman, Brandon J; Jensen, Klavs F

    2016-09-20

    microfluidics. This Account details the system configuration for on-demand creation of sub-20 μL droplets with interchangeable reagents and catalysts. These droplets are reacted in a fully automated microfluidic system and analyzed online by LC/MS. Feeding back from the online analytical results, a design of experiments (DoE)-based adaptive response surface algorithm is employed that deductively removes candidate reagents from the optimization as optimal reaction conditions are refined, leading to rapid convergence. Using the automated optimization platform, case studies are presented for solvent selection in a competitive alkylation chemistry and for catalyst-ligand selection in heteroaromatic Suzuki-Miyaura cross-coupling chemistries. For the monoalkylation of trans-1,2-diaminocyclohexane, polar aprotic solvents at moderate temperatures are shown to be favorable, with optimality accurately identified with dimethyl sulfoxide as the solvent in 67 experiments. For Suzuki-Miyaura cross-couplings, the optimality of precatalysts and continuous variable conditions are observed to change in accordance with the coupling reagents, providing insights into catalyst behavior in the context of the reaction mechanism. Future opportunities in automated reaction development include the incorporation of chemoinformatics for faster analysis and machine-learning algorithms to guide and optimize the synthesis. Adoption of this technology stands to reduce graduate student and postdoc time on routine tasks in the laboratory, while feeding back knowledge used to guide new research directions. Moreover, the application of this technology in industry promises to lessen the cost and time associated with advancing pharmaceutical molecules through development and scale-up.

  4. A topological characterization of medium-dependent essential metabolic reactions.

    Science.gov (United States)

    Sonnenschein, Nikolaus; Marr, Carsten; Hütt, Marc-Thorsten

    2012-01-01

    Metabolism has frequently been analyzed from a network perspective. A major question is how network properties correlate with biological features like growth rates, flux patterns and enzyme essentiality. Using methods from graph theory as well as established topological categories of metabolic systems, we analyze the essentiality of metabolic reactions depending on the growth medium and identify the topological footprint of these reactions. We find that the typical topological context of a medium-dependent essential reaction is systematically different from that of a globally essential reaction. In particular, we observe systematic differences in the distribution of medium-dependent essential reactions across three-node subgraphs (the network motif signature of medium-dependent essential reactions) compared to globally essential or globally redundant reactions. In this way, we provide evidence that the analysis of metabolic systems on the few-node subgraph scale is meaningful for explaining dynamic patterns. This topological characterization of medium-dependent essentiality provides a better understanding of the interplay between reaction deletions and environmental conditions. PMID:24957651

  5. A Topological Characterization of Medium-Dependent Essential Metabolic Reactions

    Directory of Open Access Journals (Sweden)

    Nikolaus Sonnenschein

    2012-09-01

    Full Text Available Metabolism has frequently been analyzed from a network perspective. A major question is how network properties correlate with biological features like growth rates, flux patterns and enzyme essentiality. Using methods from graph theory as well as established topological categories of metabolic systems, we analyze the essentiality of metabolic reactions depending on the growth medium and identify the topological footprint of these reactions. We find that the typical topological context of a medium-dependent essential reaction is systematically different from that of a globally essential reaction. In particular, we observe systematic differences in the distribution of medium-dependent essential reactions across three-node subgraphs (the network motif signature of medium-dependent essential reactions compared to globally essential or globally redundant reactions. In this way, we provide evidence that the analysis of metabolic systems on the few-node subgraph scale is meaningful for explaining dynamic patterns. This topological characterization of medium-dependent essentiality provides a better understanding of the interplay between reaction deletions and environmental conditions.

  6. Heterogeneous reactions of epoxides in acidic media.

    Science.gov (United States)

    Lal, Vinita; Khalizov, Alexei F; Lin, Yun; Galvan, Maria D; Connell, Brian T; Zhang, Renyi

    2012-06-21

    Epoxides have recently been identified as important intermediates in the gas phase oxidation of hydrocarbons, and their hydrolysis products have been observed in ambient aerosols. To evaluate the role of epoxides in the formation of secondary organic aerosols (SOA), the kinetics and mechanism of heterogeneous reactions of two model epoxides, isoprene oxide and α-pinene oxide, with sulfuric acid, ammonium bisulfate, and ammonium sulfate have been investigated using complementary experimental techniques. Kinetic experiments using a fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS) show a fast irreversible loss of the epoxides with the uptake coefficients (γ) of (1.7 ± 0.1) × 10(-2) and (4.6 ± 0.3) × 10(-2) for isoprene oxide and α-pinene oxide, respectively, for 90 wt % H(2)SO(4) and at room temperature. Experiments using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) reveal that diols are the major products in ammonium bisulfate and dilute H(2)SO(4) (65 wt %), acetals are formed from isoprene oxide, whereas organosulfates are produced from α-pinene oxide. The reaction of the epoxides with ammonium sulfate is slow and no products are observed. The epoxide reactions using bulk samples and Nuclear Magnetic Resonance (NMR) spectroscopy reveal the presence of diols as the major products for isoprene oxide, accompanied by aldehyde formation. For α-pinene oxide, organosulfate formation is observed with a yield increasing with the acidity. Large yields of organosulfates in all NMR experiments with α-pinene oxide are attributed to the kinetic isotope effect (KIE) from the use of deuterated sulfuric acid and water. Our results suggest that acid-catalyzed hydrolysis of epoxides results in the formation of a wide range of products, and some of the products have low volatility and contribute to SOA growth under ambient conditions prevailing in the urban atmosphere.

  7. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    A. Hansel

    2009-02-01

    Full Text Available Oxidation of isoprene through reaction with NO3 is a significant sink for isoprene that persists after dark. The products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene+NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 62±6% and the combined yield of MACR+MVK is found to be ~10%. Additional hydrocarbon products, thought to be primarily C4 and C5 carbonyl compounds, were observed by the PTR-MS at various m/z ratios and their yields quantified. These other oxidation products are used as additional constraints on the reaction mechanism.

  8. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    R. C. Cohen

    2009-07-01

    Full Text Available Oxidation of isoprene through reaction with NO3 radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene + NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 65±12% of which the majority was nitrooxy carbonyls and the combined yield of methacrolein and methyl vinyl ketone (MACR+MVK is found to be ∼10%. PTR-MS measurements of nitrooxy carbonyls and TD-LIF measurements of total organic nitrates agreed well. The PTR-MS also observed a series of minor oxidation products which were tentatively identified and their yields quantified These other oxidation products are used as additional constraints on the reaction mechanism.

  9. Spatial model of autocatalytic reactions

    OpenAIRE

    De Anna, Pietro; Di Patti, Francesca; Fanelli, Duccio; McKane, Alan J.; Dauxois, Thierry

    2010-01-01

    Biological cells with all of their surface structure and complex interior stripped away are essentially vesicles - membranes composed of lipid bilayers which form closed sacs. Vesicles are thought to be relevant as models of primitive protocells, and they could have provided the ideal environment for pre-biotic reactions to occur. In this paper, we investigate the stochastic dynamics of a set of autocatalytic reactions, within a spatially bounded domain, so as to mimic a primordial cell. The ...

  10. Thermodynamics of random reaction networks.

    Directory of Open Access Journals (Sweden)

    Jakob Fischer

    Full Text Available Reaction networks are useful for analyzing reaction systems occurring in chemistry, systems biology, or Earth system science. Despite the importance of thermodynamic disequilibrium for many of those systems, the general thermodynamic properties of reaction networks are poorly understood. To circumvent the problem of sparse thermodynamic data, we generate artificial reaction networks and investigate their non-equilibrium steady state for various boundary fluxes. We generate linear and nonlinear networks using four different complex network models (Erdős-Rényi, Barabási-Albert, Watts-Strogatz, Pan-Sinha and compare their topological properties with real reaction networks. For similar boundary conditions the steady state flow through the linear networks is about one order of magnitude higher than the flow through comparable nonlinear networks. In all networks, the flow decreases with the distance between the inflow and outflow boundary species, with Watts-Strogatz networks showing a significantly smaller slope compared to the three other network types. The distribution of entropy production of the individual reactions inside the network follows a power law in the intermediate region with an exponent of circa -1.5 for linear and -1.66 for nonlinear networks. An elevated entropy production rate is found in reactions associated with weakly connected species. This effect is stronger in nonlinear networks than in the linear ones. Increasing the flow through the nonlinear networks also increases the number of cycles and leads to a narrower distribution of chemical potentials. We conclude that the relation between distribution of dissipation, network topology and strength of disequilibrium is nontrivial and can be studied systematically by artificial reaction networks.

  11. Psychosocial reactions to physical illness.

    OpenAIRE

    Lipowski, Z J

    1983-01-01

    Recently medical educators have emphasized the need for physicians to acquire the skills to deal with psychologic aspects of patient care. To facilitate this task a descriptive schema is presented for use in evaluating patients' psychosocial reactions to physical illness. Three core components of such reactions are: the personal meaning of illness, emotional responses to illness and modes of coping with illness. Clinical application of this schema may help with patient management and prevent ...

  12. Drug Reactions in Oral Mucosa

    Directory of Open Access Journals (Sweden)

    Emine Derviş

    2012-12-01

    Full Text Available Both immunologic and nonimmunologic drug reactions can be seen in oral mucosa. Since considerable number of these reactions heals spontaneously without being noticed by the patients, exact frequency of the lesions is unknown. Most common lesions are xerostomia, taste disorders, mucosal ulcerations and edema. In this article, oral lesions resulting from drug intake similar to those from oral lesions of local and systemic diseases, and diagnostic problems caused by these similarities, have been reviewed.

  13. Enantioselectivity of Photochemical Reactions within Polymer Microcapsules

    Institute of Scientific and Technical Information of China (English)

    MA,Lei; WU,Li-Zhu; ZHANG,Li-Ping; TUNG,Chen-Ho

    2003-01-01

    Polymer microcapsule was employed as a reaction medium to achieve enantioselectivity in photochemical reduction of phenyl cyclohexyl ketone and photoelectrocyclization of tropolone methyl ether unader the influence of various chiral inductors. In all cases,low but evident enantioselectivity was observed. The poor enantioselectivity is probably due to the facts that not all the capsules include simultaneously both the chiral inductor and the reactant molecules, and the wall of the microcapsule is not rigid enough tohold the reactant and the chiral inductor moleculesin close contact.

  14. Nuclear Reactions Used For Superheavy Element Research

    Science.gov (United States)

    Stoyer, Mark A.

    2008-04-01

    Some of the most fascinating questions about the limits of nuclear stability are confronted in the heaviest nuclei. How many more new elements can be synthesized? What are the nuclear and chemical properties of these exotic nuclei? Does the "Island of Stability" exist and can we ever explore the isotopes inhabiting that nuclear region? This paper will focus on the current experimental research on the synthesis and characterization of superheavy nuclei with Z>112 from the Dubna/Livermore collaboration. Reactions using 48Ca projectiles from the U400 cyclotron and actinide targets (233,238U, 237Np, 242,244Pu, 243Am, 245,248Cm, 249Cf) have been investigated using the Dubna Gas Filled Recoil Separator in Dubna over the last 8 years. In addition, several experiments have been performed to investigate the chemical properties of some of the observed longer-lived isotopes produced in these reactions. Some comments will be made on nuclear reactions used for the production of the heaviest elements. A summary of the current status of the upper end of the chart of nuclides will be presented.

  15. Bayesian Estimation of Thermonuclear Reaction Rates

    CERN Document Server

    Iliadis, Christian; Coc, Alain; Timmes, Frank; Starrfield, Sumner

    2016-01-01

    The problem of estimating non-resonant astrophysical S-factors and thermonuclear reaction rates, based on measured nuclear cross sections, is of major interest for nuclear energy generation, neutrino physics, and element synthesis. Many different methods have been applied in the past to this problem, all of them based on traditional statistics. Bayesian methods, on the other hand, are now in widespread use in the physical sciences. In astronomy, for example, Bayesian statistics is applied to the observation of extra-solar planets, gravitational waves, and type Ia supernovae. However, nuclear physics, in particular, has been slow to adopt Bayesian methods. We present the first astrophysical S-factors and reaction rates based on Bayesian statistics. We develop a framework that incorporates robust parameter estimation, systematic effects, and non-Gaussian uncertainties in a consistent manner. The method is applied to the d(p,$\\gamma$)$^3$He, $^3$He($^3$He,2p)$^4$He, and $^3$He($\\alpha$,$\\gamma$)$^7$Be reactions,...

  16. Reaction mechanisms in heavy ion fusion

    Directory of Open Access Journals (Sweden)

    Lubian J.

    2011-10-01

    Full Text Available We discuss the reaction mechanisms involved in heavy ion fusion. We begin with collisions of tightly bound systems, considering three energy regimes: energies above the Coulomb barrier, energies just below the barrier and deep sub-barrier energies. We show that channel coupling effects may influence the fusion process at above-barrier energies, increasing or reducing the cross section predicted by single barrier penetration model. Below the Coulomb barrier, it enhances the cross section, and this effect increases with the system’s size. It is argued that this behavior can be traced back to the increasing importance of Coulomb coupling with the charge of the collision partners. The sharp drop of the fusion cross section observed at deep sub-barrier energies is addressed and the theoretical approaches to this phenomenon are discussed. We then consider the reaction mechanisms involved in fusion reactions of weakly bound systems, paying particular attention to the calculations of complete and incomplete fusion available in the literature.

  17. Photochemical Reactions of Cyclohexanone: Mechanisms and Dynamics.

    Science.gov (United States)

    Shemesh, Dorit; Nizkorodov, Sergey A; Gerber, R Benny

    2016-09-15

    Photochemistry of carbonyl compounds is of major importance in atmospheric and organic chemistry. The photochemistry of cyclohexanone is studied here using on-the-fly molecular dynamics simulations on a semiempirical multireference configuration interaction potential-energy surface to predict the distribution of photoproducts and time scales for their formation. Rich photochemistry is predicted to occur on a picosecond time scale following the photoexcitation of cyclohexanone to the first singlet excited state. The main findings include: (1) Reaction channels found experimentally are confirmed by the theoretical simulations, and a new reaction channel is predicted. (2) The majority (87%) of the reactive trajectories start with a ring opening via C-Cα bond cleavage, supporting observations of previous studies. (3) Mechanistic details, time scales, and yields are predicted for all reaction channels. These benchmark results shed light on the photochemistry of isolated carbonyl compounds in the atmosphere and can be extended in the future to photochemistry of more complex atmospherically relevant carbonyl compounds in both gaseous and condensed-phase environments.

  18. Observation on the Efficacy of Small Dose of Esmolol Intravenous Pre-injection Alleviating the Reac-tion of Tracheal Intubation for Patients with Hypertension and Coronary Heart Disease%小剂量艾司洛尔预先静脉注射减轻高血压冠心病患者气管插管反应的疗效观察

    Institute of Scientific and Technical Information of China (English)

    王光福; 徐小波; 李河志; 赵辉; 刘绍靖

    2016-01-01

    目的 观察小剂量艾司洛尔预先静脉注射在减轻高血压冠心病患者气管插管反应的作用. 方法 选取2009年2月至2012年10月在武装警察部队四川总队成都医院行全身麻醉手术的高血压冠心病患者60例,根据随机数字表法分为艾司洛尔组和对照组,各30 例. 艾司洛尔组在麻醉插管前5 min给予小剂量艾司洛尔(0.7 mg/kg);对照组仅给予0.9%NaCl注射液,两组麻醉诱导和维持方法相同,分别监测并记录麻醉诱导前、诱导后、插管即刻、插管后1、3、5 min时心率和平均动脉压变化. 结果 对照组插管即刻、插管1、3、5 min 的平均动脉压较诱导前有明显升高[ ( 120 ± 15)mmHg(1 mmHg=0.133 kPa)、(118 ±23) mmHg、(115 ±10) mmHg、(112 ±14) mmHg 比(98 ± 14) mmHg],心率明显增快[(88 ±8)次/min、(94 ±15)次/min、(91 ±10)次/min、(93 ±10)次/min比(76 ±4)次/min],艾司洛尔组的平均动脉压[(101 ±11) mmHg、(104 ±18) mmHg、(101 ± 10) mmHg、(98 ±10) mmHg比(98 ±14) mmHg],心率[(78 ±4)次/min、(81 ±12)次/min、(80 ± 7)次/min、(78 ±5)次/min比(75 ±7)次/min]分别较诱导前有轻度升高,但变化幅度不大. 两组比较差异有统计学意义( P<0.05 ). 结论 小剂量艾司洛尔预先注射能够有效减轻高血压冠心病患者气管插管时的心血管反应.%Objective To observe the effect of intravenous pre-injection of small dose of esmolol on alle-viating the impact of tracheal intubation on patients with hypertension and coronary heart disease .Methods Total of 60 patients with hypertension and coronary heart disease undergoing general anesthesia operations at Chengdu Armed Police Corps Hospital from Feb.2009 to Oct.2012 were selected, and were divide into esmolol group and control group according to random number table method,with 30 patients in each group. The esmolol group was injected with small dose of esmolol(0.7 mg/kg) 5 minutes prior to the anesthetic intubation;the control

  19. Reaction rates for mesoscopic reaction-diffusion kinetics.

    Science.gov (United States)

    Hellander, Stefan; Hellander, Andreas; Petzold, Linda

    2015-02-01

    The mesoscopic reaction-diffusion master equation (RDME) is a popular modeling framework frequently applied to stochastic reaction-diffusion kinetics in systems biology. The RDME is derived from assumptions about the underlying physical properties of the system, and it may produce unphysical results for models where those assumptions fail. In that case, other more comprehensive models are better suited, such as hard-sphere Brownian dynamics (BD). Although the RDME is a model in its own right, and not inferred from any specific microscale model, it proves useful to attempt to approximate a microscale model by a specific choice of mesoscopic reaction rates. In this paper we derive mesoscopic scale-dependent reaction rates by matching certain statistics of the RDME solution to statistics of the solution of a widely used microscopic BD model: the Smoluchowski model with a Robin boundary condition at the reaction radius of two molecules. We also establish fundamental limits on the range of mesh resolutions for which this approach yields accurate results and show both theoretically and in numerical examples that as we approach the lower fundamental limit, the mesoscopic dynamics approach the microscopic dynamics. We show that for mesh sizes below the fundamental lower limit, results are less accurate. Thus, the lower limit determines the mesh size for which we obtain the most accurate results.

  20. Reaction rates for a generalized reaction-diffusion master equation.

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2016-01-01

    It has been established that there is an inherent limit to the accuracy of the reaction-diffusion master equation. Specifically, there exists a fundamental lower bound on the mesh size, below which the accuracy deteriorates as the mesh is refined further. In this paper we extend the standard reaction-diffusion master equation to allow molecules occupying neighboring voxels to react, in contrast to the traditional approach, in which molecules react only when occupying the same voxel. We derive reaction rates, in two dimensions as well as three dimensions, to obtain an optimal match to the more fine-grained Smoluchowski model and show in two numerical examples that the extended algorithm is accurate for a wide range of mesh sizes, allowing us to simulate systems that are intractable with the standard reaction-diffusion master equation. In addition, we show that for mesh sizes above the fundamental lower limit of the standard algorithm, the generalized algorithm reduces to the standard algorithm. We derive a lower limit for the generalized algorithm which, in both two dimensions and three dimensions, is of the order of the reaction radius of a reacting pair of molecules.

  1. Reaction rates for a generalized reaction-diffusion master equation

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2016-01-01

    It has been established that there is an inherent limit to the accuracy of the reaction-diffusion master equation. Specifically, there exists a fundamental lower bound on the mesh size, below which the accuracy deteriorates as the mesh is refined further. In this paper we extend the standard reaction-diffusion master equation to allow molecules occupying neighboring voxels to react, in contrast to the traditional approach, in which molecules react only when occupying the same voxel. We derive reaction rates, in two dimensions as well as three dimensions, to obtain an optimal match to the more fine-grained Smoluchowski model and show in two numerical examples that the extended algorithm is accurate for a wide range of mesh sizes, allowing us to simulate systems that are intractable with the standard reaction-diffusion master equation. In addition, we show that for mesh sizes above the fundamental lower limit of the standard algorithm, the generalized algorithm reduces to the standard algorithm. We derive a lower limit for the generalized algorithm which, in both two dimensions and three dimensions, is of the order of the reaction radius of a reacting pair of molecules.

  2. Reaction rates for mesoscopic reaction-diffusion kinetics

    Science.gov (United States)

    Hellander, Stefan; Hellander, Andreas; Petzold, Linda

    2015-02-01

    The mesoscopic reaction-diffusion master equation (RDME) is a popular modeling framework frequently applied to stochastic reaction-diffusion kinetics in systems biology. The RDME is derived from assumptions about the underlying physical properties of the system, and it may produce unphysical results for models where those assumptions fail. In that case, other more comprehensive models are better suited, such as hard-sphere Brownian dynamics (BD). Although the RDME is a model in its own right, and not inferred from any specific microscale model, it proves useful to attempt to approximate a microscale model by a specific choice of mesoscopic reaction rates. In this paper we derive mesoscopic scale-dependent reaction rates by matching certain statistics of the RDME solution to statistics of the solution of a widely used microscopic BD model: the Smoluchowski model with a Robin boundary condition at the reaction radius of two molecules. We also establish fundamental limits on the range of mesh resolutions for which this approach yields accurate results and show both theoretically and in numerical examples that as we approach the lower fundamental limit, the mesoscopic dynamics approach the microscopic dynamics. We show that for mesh sizes below the fundamental lower limit, results are less accurate. Thus, the lower limit determines the mesh size for which we obtain the most accurate results.

  3. Nuclear Reactions for Astrophysics and Other Applications

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Burke, J T; Dietrich, F S; Scielzo, N D; Ressler, J J

    2011-03-01

    Cross sections for compound-nuclear reactions are required for many applications. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  4. The severe adverse reaction to vitamin k1 injection is anaphylactoid reaction but not anaphylaxis.

    Science.gov (United States)

    Mi, Yan-Ni; Ping, Na-Na; Xiao, Xue; Zhu, Yan-Bing; Liu, Jing; Cao, Yong-Xiao

    2014-01-01

    The severe adverse reaction to vitamin K1 injection is always remarkable and is thought to result from anaphylaxis. Paradoxically, however, some patients administered vitamin K1 injection for the first time have adverse reactions. Using beagle dogs, the present study tested the hypothesis that the response to vitamin K1 is an anaphylactoid reaction. The results showed that serious anaphylaxis-like symptoms appeared in beagle dogs after the administration of vitamin K1 injection for the first time. The plasma histamine concentration increased, and blood pressure decreased sharply. After sensitization, dogs were challenged with vitamin K1 injection and displayed the same degree of symptoms as prior to sensitization. However, when the vitamin K1 injection-sensitized dogs were challenged with a vitamin K1-fat emulsion without solubilizers such asTween-80, the abnormal reactions did not occur. Furthermore, there was no significant change in the plasma immunoglobulin E concentration after vitamin K1 challenge. Following treatment with vitamin K1 injection, the release of histamine and β-hexosaminidase by rat basophilic leukemia-2H3 cells as well as the rate of apoptosis increased. The Tween-80 group displayed results similar to those observed following vitamin K1 injection in vivo. However, the dogs in the vitamin K1-fat emulsion group did not display any abnormal behavior or significant change in plasma histamine. Additionally, degranulation and apoptosis did not occur in rat basophilic leukemia-2H3 cells. Our results indicate that the adverse reaction induced by vitamin K1 injection is an anaphylactoid reaction, not anaphylaxis. Vitamin K1 injection induces the release of inflammatory factors via a non-IgE-mediated immune pathway, for which the trigger may be the solubilizer. PMID:24594861

  5. The severe adverse reaction to vitamin k1 injection is anaphylactoid reaction but not anaphylaxis.

    Directory of Open Access Journals (Sweden)

    Yan-Ni Mi

    Full Text Available The severe adverse reaction to vitamin K1 injection is always remarkable and is thought to result from anaphylaxis. Paradoxically, however, some patients administered vitamin K1 injection for the first time have adverse reactions. Using beagle dogs, the present study tested the hypothesis that the response to vitamin K1 is an anaphylactoid reaction. The results showed that serious anaphylaxis-like symptoms appeared in beagle dogs after the administration of vitamin K1 injection for the first time. The plasma histamine concentration increased, and blood pressure decreased sharply. After sensitization, dogs were challenged with vitamin K1 injection and displayed the same degree of symptoms as prior to sensitization. However, when the vitamin K1 injection-sensitized dogs were challenged with a vitamin K1-fat emulsion without solubilizers such asTween-80, the abnormal reactions did not occur. Furthermore, there was no significant change in the plasma immunoglobulin E concentration after vitamin K1 challenge. Following treatment with vitamin K1 injection, the release of histamine and β-hexosaminidase by rat basophilic leukemia-2H3 cells as well as the rate of apoptosis increased. The Tween-80 group displayed results similar to those observed following vitamin K1 injection in vivo. However, the dogs in the vitamin K1-fat emulsion group did not display any abnormal behavior or significant change in plasma histamine. Additionally, degranulation and apoptosis did not occur in rat basophilic leukemia-2H3 cells. Our results indicate that the adverse reaction induced by vitamin K1 injection is an anaphylactoid reaction, not anaphylaxis. Vitamin K1 injection induces the release of inflammatory factors via a non-IgE-mediated immune pathway, for which the trigger may be the solubilizer.

  6. Chaos in the Showalter-Noyes-Bar-Eli model of the Belousov-Zhabotinskii reaction

    Science.gov (United States)

    Lindberg, David; Turner, Jack S.; Barkley, Dwight

    1990-03-01

    The observation of robust, large-scale chaos in the Showalter-Noyes-Bar-Eli model of the Belousov-Zhabotinskii reaction is reported. The chaos observed is comparable to that found in CSTR experiments at low flow rates.

  7. Biodegradable PELA block copolymers: in vitro degradation and tissue reaction.

    Science.gov (United States)

    Younes, H; Nataf, P R; Cohn, D; Appelbaum, Y J; Pizov, G; Uretzky, G

    1988-01-01

    Degradation of, and tissue reaction elicited by a series of polyethylene oxide (PEO)/polylactic acid (PLA) PELA block copolymers were studied in vitro and in vivo. In particular, the effect of pH, temperature and enzymatic activity was addressed. The mass loss was faster, the more basic the media, while, expectedly, PELA copolymers degraded faster with the higher temperature. The addition of an enzyme (carboxylic ester hydrolase) had no effect. The degradation process strongly affected the mechanical properties of the materials under investigation, the elongation at break dropping drastically after two days of degradation. After seven days, only gross observation of the extensively degraded samples was possible. The in vivo studies compared the tissue reaction elicited by various PELA copolymers to that evoked by PLA. Evaluation of tissue reaction observed with a PELA sample after sterilization with gamma radiation showed acute inflammation with considerable dispersion of the material, 12 days after implantation. The granulomatous reaction observed with PELA copolymers after ethylene oxide sterilization was identical to the reaction observed with PLA. PMID:3064826

  8. Small Organic Molecules for Direct Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    TANG Zhuo; GONG Liu-Zhu; MI Ai-Qiao; JIANG Yao-Zhong

    2004-01-01

    Since the pioneering finding by List and Barbas Ⅲ and their coworkers that L-proline could work as a catalyst in the intermolecular direct aldol reaction, the concept of small organic molecules as catalysts has received great attention. However, new organic molecule which have better catalysis ability are reported scarcely.Our groups1 found L-Prolinamides 1 to be active catalysts for the direct aldol reaction of 4-nitrobenaldehyde with neat acetone at room temperature. The enantioselectivity increases as the amide N-H becomes more acidic and thus a better hydrogen bond donor. Introducing another proton donor, hydroxyl, in the catalyst lead to a further improvement in the catalytic enantioselectivity.The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity.Catalyst 2, prepared from L-proline and (1S, 2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes. It is noteworthy that our results refuted the conventional wisdom that the carboxylic acid group of proline is a reqirement for high enatioselectivity and provide a powerful strategy in the molecular design of new organic catalyst because plentiful chiral resource containing multi-hydrogen bonding donor, for example, peptides.Very recently, we found that L-proline-based peptides 3-7 can catalyze the aldol reactions of hydroxyacetone with aldehydes 8 in aqueous media, to give 1,4-diols 9, the disfavored products with either aldolase or L-proline. Both peptides 5 and 6 give good results.The abilities of peptides 5 and 6 to catalyze the direct aldol reactions of hydroxyacetone with avariety of aldehydes were examined under optimal conditions. The results are shown in table. Highyields and entioselectivities of up to 96% ee were observed for aromatic aldehydes

  9. Spectroscopy and reaction kinetics of HCO

    International Nuclear Information System (INIS)

    The high-resolution infrared spectrum of the C-H stretching fundamental of HCO has been studied by means of infrared flash kinetic spectroscopy. HCO was generated by flash photolysis of acetaldehyde or formaldehyde using a 308 nm (XeCl) excimer laser. The transient absorption was probed with an infrared difference frequency laser system. The high resolution spectra obtained were assigned and fitted with rotational, spin-rotational, and centrifugal distortion constants. The ν1 band origin is 2434.48 cm/sup /minus/1/. New ground state constants have been derived from a least-squares fit combining the ν1 data with previous microwave and FIR LMR measurements. A new set of spectroscopic constants for the (1, 0, 0) state, the equilibrium rotational constants, and the orientation of the transition dipole moment are also reported. The kinetics and product branching ratios of the HCO + NO2 reaction have been studied using visible and infrared laser flash kinetic spectroscopy. The rate constant for the disappearance of HCO radical at 296 K is (5.7 +- 0.9) /times/ 10/sup /minus/11/ cm3 molec/sup /minus/1/ sec/sup /minus/1/, and it is independent of the pressure of SF6 buffer gas up to 700 torr. Less than 10% of the reaction goes through the most exothermic product channel, HNO + CO2. The product channel, H + CO2 + NO, is responsible for 52% of the reaction. HONO has been observed, though not quantitatively, as a reaction product corresponding to the HONO + CO channel. 51 refs., 21 figs., 8 tabs

  10. Exchange Reactions. Proceedings of the Symposium on Exchange Reactions

    International Nuclear Information System (INIS)

    The mechanisms and kinetics of chemical reactions are of great interest to chemists. The study of exchange reactions in particular helps to shed light on the dynamics of chemical change, providing an insight into the structures and the reactivities of the chemical species involved. The main theme of this meeting was the subject of oxidation-reduction reactions in which the net result is the transfer of one or more electrons between the different oxidation states of the same element. Other studies reported included the transfer of protons, atoms, complex ligands or organic radicals between molecules. Heterogeneous exchange, which is of importance in many cases of catalytic action, was also considered. For a long time isotopic tracers have formed the most convenient means of studying exchange reactions and today a considerable amount of work continues to be done with their aid. Consequently, several papers presented at this Symposium reported on work carried out by purely radiochemical tracer methods. In recognition, however, of the important role which nuclear magnetic resonance and electron spin resonance play in this field, in particular in the study of fast reactions, a number of reports on investigations in which these techniques had been used was included in the programme. By kind invitation of the United States Government the Symposium on Exchange Reactions was held from 31 May to 4 June at the Brookhaven National Laboratory, Upton, Long Island, N.Y., USA. It was attended by 46 participants from nine countries and one inter-governmental organization. The publication of these Proceedings makes the contents of the papers and the discussion available to a wider audience

  11. A comprehensive survey of nuclear reactions; Panorama des reactions nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cugnon, J. [Liege Univ., IFPA, AGO Dept. (Belgium)

    2007-07-01

    The various mechanisms of nuclear reactions are surveyed and classified in different regimes, based on the notions of coherent mechanisms and hard versus soft processes. The emphasis is put on the concepts at the basis of the understanding of these regimes and on the elements of nuclear structure which are involved in these different regimes, as well as the on the possibility of extracting this information. Due to lack of space and for pedagogical reasons, the discussion is limited to nucleon-induced and light-ion-induced reactions. However, a few remarks are given concerning some specific probes, such as weakly bound projectiles or neutron-rich nuclei. (author)

  12. Acute anaphylactic reaction to expired chlorpheniramine injection

    Institute of Scientific and Technical Information of China (English)

    Beuy Joob; Viroj Wiwanitkit

    2014-01-01

    Chlorpheniramine is a widely used drug for management of allergic reaction.The serious adverse reaction to this drug is extremely rare.In this report, the authors present a case of acute anaphylactic reaction to expired chlorpheniramine injection.

  13. Combustion kinetics and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  14. Reaction of iodine atoms with submicrometer squalane and squalene droplets: mechanistic insights into heterogeneous reactions.

    Science.gov (United States)

    Popolan-Vaida, Denisia M; Wilson, Kevin R; Leone, Stephen R

    2014-11-13

    The gas-phase reaction of iodine atoms with hydrocarbon molecules is energetically unfavorable, and there is no direct evidence for iodinated product formation by either H abstraction or I addition reactions at ambient temperature. Here we consider the possible heterogeneous reaction of I atoms with submicrometer droplets composed of a saturated alkane, squalane (Sq), and an unsaturated alkene, squalene (Sqe). The investigations are performed in an atmospheric pressure photochemical flow tube reactor in conjunction with a vacuum ultraviolet photoionization aerosol mass spectrometer and a scanning mobility particle sizer. Squalane, a branched alkane, is unreactive toward I atoms within the signal-to-noise, and an upper limit of the effective reactive uptake coefficient is estimated to be γI(Sq) ≤ 8.58 × 10(–7). In contrast, the reaction of I atoms with unsaturated submicrometer squalene droplets results in observable iodinated squalene products. The effective reactive uptake coefficient of I atom with squalene particles is determined to be γI(Sqe) = (1.20 ± 0.52) × 10(–4) at an average I concentration of 1.5 × 10(14) molecules·cm(–3).

  15. The Reaction of Acenaphthene with Nitrobenzene

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reaction of acenaphthene with nitrobenzene was investigated in the presence of AlCl3 . The results showed that the reaction proceeded via carboncation-electrophilic substitution reaction and free radical substitution reaction pathway. The products of acenaphthenyl phenylamine and biacenaphthyl could be synthesized by this reaction. The influence of the amount of AlCl3 and the temperature on the components of products were also studied in this reaction.

  16. Adverse Reactions to Radiographic Contrast Material

    OpenAIRE

    Bush, William H.; Mullarkey, Michael F.; Webb, D. Robert

    1980-01-01

    Major adverse reactions to radiographic contrast media will occur more often as contrast material is now also administered during computerized tomographic (CT) scanning. Differentiation of the two major contrast reactions, the vagus reaction and the anaphylactoid reaction, is essential. Bradycardia is the key finding for identifying the vagus reaction. The vagus reaction involving hypotension and bradycardia requires treatment with large doses of atropine given intravenously. The immediate ge...

  17. Fission in intermediate energy heavy ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmy, J.B.; Begemann-Blaich, M.; Blaich, T.; Boissevain, J.; Fowler, M.M.; Gavron, A.; Jacak, B.V.; Lysaght, P.S. (Los Alamos National Lab., NM (USA)); Britt, H.C.; Fields, D.J.; Hansen, L.F.; Lanier, R.G.; Massoletti, D.J.; Namboodiri, M.M.; Remington, B.A.; Sangster, T.C.; Struble, G.L.; Webb, M.L. (Lawrence Livermore National Lab., CA (USA)); Chan, Y.D.; Dacai, A.; Harmon, A.; Leyba, J.; Pouliot, J.; Stokstad, R.G. (Lawrence Berkeley Lab., CA (USA)); Hansen, O.; Levine, M.J.; Thorn, C.E.; Trautmann, W. (Brookhaven National Lab., Upton, NY (USA)); Dichter, B.; Kaufman, S.; Videbaek, F. (Argonne National Lab. (USA)); Fraenkel, Z.; Mamane, G. (Weizmann Inst. of Science, Rehovoth (Israel)); Cebra, D.; Westfall, G.D. (Michigan State Univ., East Lansing (USA))

    1989-10-09

    A systematic study of reaction mechanisms at intermediate energies (50-100 MeV/A) has been performed at the Lawrence Berkeley Laboratory's BeValac using medium weight projectiles on medium and heavy element targets. A gas and plastic phoswich detector system was employed which gave large geometric coverage and a wide dynamic response. The particles identified with the gas detectors could be characterized into three components - intermediate mass fragments (IMF), fission fragments (FF) and heavy residues (HR). Major observed features are: The reaction yields are similar in the 50 to 100 MeV/A range, central collisions have high multiplicty of IMF's with broad angular correlations consistent with a large participant region, effects of final state Coulomb interactions are observed and give information on the size and temporal behavior of the source, true fission yields are dependent on target fissility and correlated with relatively peripheral collisions. Analysis of fission and evaporation yields implies limiting conditions for which fission decay remains a viable deexcitation channel. (orig.).

  18. Images of mycobacterium for nuclear reactions

    International Nuclear Information System (INIS)

    According to the World Health Organization (WHO) tuberculosis is responsible for 2.9 million deaths annually worldwide. The necessity for optimizing time to detect the tuberculosis bacillus (mycobacterium tuberculosis) in the sputum samples of affected individuals (TB patients) led to the development of a methodology based on the doping with boron of the bacillus, submission of the samples to thermal neutron beam and ionizing particles, generating nuclear reactions of the types: 10B (n,α)7Li and 10 B(α, p)13C. Images of these bacilli are obtained by means of the nuclear tracks produced in the CR-39 detector for particles products of these nuclear reactions, α and p. When the CR-39 is submitted to a chemical attack the traces are developed and the images of the microorganisms registered in the detector can be observed with a conventional light microscope, characterizing them by morphology. The use of this methodology results in images of the mycobacterium tuberculosis becoming more defined and enlarged than those obtained by bacilloscopy, in which the sample is submitted to the method of coloration of Ziehl-Neelsen (ZN) and observed in light microscopy. (author)

  19. OXYGEN-18 + OXYGEN-18 Reactions.

    Science.gov (United States)

    Yuan, Ren-Feng

    Cross sections for the ^{18 }O + ^{18}O reactions (fusion, inelastic excitation and transfer reactions) have been determined in the range 6.73 <=q E_{c.m}<=q 13.24 MeV by measuring the low-lying gamma-ray transitions in the residual nuclei with a high resolution Ge detector. A statistical model calculation of the populations of the residual nuclear states was employed in deducing cross sections from the measured gamma -yields. gamma-ray angular distributions were determined at E_{lab} = 20.0 MeV. The total fusion cross sections were compared with an IWBC calculation employing a parameter set obtained from fitting elastic scattering data. The interaction barrier shape has been obtained by means of the BKN inversion procedure and compared with the barriers for other oxygen isotopes. The inelastic scattering cross section and the two-neutron transfer reaction cross section are reproduced well by the DWBA approach.

  20. Photonuclear reactions on titanium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Belyshev, S. S. [Moscow State University (Russian Federation); Dzhilavyan, L. Z. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ishkhanov, B. S.; Kapitonov, I. M. [Moscow State University (Russian Federation); Kuznetsov, A. A., E-mail: kuznets@depni.sinp.msu.ru; Orlin, V. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  1. Spatial model of autocatalytic reactions

    Science.gov (United States)

    de Anna, Pietro; di Patti, Francesca; Fanelli, Duccio; McKane, Alan J.; Dauxois, Thierry

    2010-05-01

    Biological cells with all of their surface structure and complex interior stripped away are essentially vesicles—membranes composed of lipid bilayers which form closed sacs. Vesicles are thought to be relevant as models of primitive protocells, and they could have provided the ideal environment for prebiotic reactions to occur. In this paper, we investigate the stochastic dynamics of a set of autocatalytic reactions, within a spatially bounded domain, so as to mimic a primordial cell. The discreteness of the constituents of the autocatalytic reactions gives rise to large sustained oscillations even when the number of constituents is quite large. These oscillations are spatiotemporal in nature, unlike those found in previous studies, which consisted only of temporal oscillations. We speculate that these oscillations may have a role in seeding membrane instabilities which lead to vesicle division. In this way synchronization could be achieved between protocell growth and the reproduction rate of the constituents (the protogenetic material) in simple protocells.

  2. Postcolumn reaction detectors for HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Frei, R.W.; Jansen, H.; Brinkman, U.A.T.

    1985-12-01

    Currently, the best and most reliable HPLC (high-performance liquid chromatography) detectors are UV-VIS absorbance, fluorescence, and electrochemical detectors. It is attractive to try to expand their range of application by using suitable chemical derivatization techniques to convert the analytes of interest with their originally poor detection properties into compounds that can be detected with high sensitivity with these detectors. Besides an improvement of the detection properties, the chemical reaction can also enhance the selectivity of the total analytical method. The derivatization can be carried out either prior to the HPLC separation or by doing the reaction in an on-line postcolumn mode. Comparative advantages and disadvantages of these two approaches have been discussed previously. This paper will discuss on-line postcolumn derivatization. A general scheme of an HPLC system equipped with an on-line postcolumn reaction detector is given. 40 references, 6 figures, 2 tables.

  3. Anaphylactoid reactions to radiocontrast media.

    Science.gov (United States)

    Canter, Lauren M

    2005-01-01

    As the role for diagnostic and therapeutic contrast-enhanced imaging increases, review of the epidemiology, mechanisms, risk factors, and pretreatment for radiocontrast-mediated anaphylactoid reactions becomes more and more pertinent. Ongoing research has failed to elucidate the precise mechanisms of both early and late reactions, though the current data point to a multifactorial pathogenesis. The risk of reactions has decreased over time as contrast media have evolved from ionic, high-osmolality to nonionic, low-osmolality formulations; however, the expense of the low-osmolality agents limit their universal use. Today, 1-12% of patients exhibit adverse responses ranging from mild to severe, with individual risk depending on the type of contrast administered and certain baseline patient characteristics. For those high-risk patients who must receive contrast, effective pretreatment guidelines have been established. PMID:16119034

  4. Light in elementary biological reactions

    Science.gov (United States)

    Sundström, Villy

    2000-09-01

    Light plays an important role in biology. In this review we discuss several processes and systems where light triggers a biological response, i.e. photosynthesis, vision, photoreceptors. For these functions Nature has chosen simple elementary chemical reactions, which occur in highly specialized and organized structures. The high efficiency and specificity of these reactions make them interesting for applications in light energy conversion and opto-electronics. In order to emphasize the synergism in studies of natural and synthetic systems we will discuss a few of each kind, with similar functions. In all cases light triggers a rapid sequence of events, which makes ultrafast spectroscopy an ideal tool to disentangle reaction mechanisms and dynamics.

  5. Inorganic Reaction Mechanisms Part II: Homogeneous Catalysis

    Science.gov (United States)

    Cooke, D. O.

    1976-01-01

    Suggests several mechanisms for catalysis by metal ion complexes. Discusses the principal factors of importance in these catalysis reactions and suggests reactions suitable for laboratory study. (MLH)

  6. Microscopic effective reaction theory for direct nuclear reactions

    Directory of Open Access Journals (Sweden)

    Ogata Kazuyuki

    2016-01-01

    Full Text Available Some recent activities with the microscopic effective reaction theory (MERT on elastic, inelastic, breakup, transfer, and knockout processes are reviewed briefly. As a possible alternative to MERT, a description of elastic and inelastic scattering with the continuum particle-vibration coupling (cPVC method is also discussed.

  7. Reactions of Pseudomonas aeruginosa pyocyanin with reduced glutathione.

    Science.gov (United States)

    Cheluvappa, Rajkumar; Shimmon, Ronald; Dawson, Michael; Hilmer, Sarah N; Le Couteur, David G

    2008-01-01

    Pseudomonas aeruginosa is the most common cause of chronic and recurrent lung infections in patients with cystic fibrosis (CF) whose sputa contain copious quantities of P. aeruginosa toxin, pyocyanin. Pyocyanin triggers tissue damage mainly by its redox cycling and induction of reactive oxygen species (ROS). The reactions between reduced glutathione (GSH) and pyocyanin were observed using absorption spectra from spectrophotometry and the reaction products analysed by nuclear magnetic resonance imaging. Pyocyanin reacted with GSH non-enzymatically at 37 degrees C resulting in the production of red-brown products, spectophotometrically visible as a 480 nm maximum absorption peak after 24 h of incubation. The reaction was concentration-dependent on reduced glutathione but not on pyocyanin. Minimizing the accessibility of oxygen to the reaction decreased its rate. The anti-oxidant enzyme catalase circumvented the reaction. Proton-NMR analysis demonstrated the persistence of the original aromatic ring and the methyl-group of pyocyanin in the red-brown products. Anti-oxidant agents having thiol groups produced similar spectophotometrically visible peaks. The presence of a previously unidentified non-enzymatic GSH-dependent metabolic pathway for pyocyanin has thus been identified. The reaction between pyocyanin and GSH is concentration-, time-, and O(2)-dependent. The formation of H(2)O(2) as an intermediate and the thiol group in GSH seem to be important in this reaction. PMID:18797520

  8. Geometric phase effects in ultracold hydrogen exchange reaction

    Science.gov (United States)

    Hazra, Jisha; Kendrick, Brian K.; Balakrishnan, N.

    2016-10-01

    The role of the geometric phase effect on chemical reaction dynamics is explored by examining the hydrogen exchange process in the fundamental H+HD reaction. Results are presented for vibrationally excited HD molecules in the v = 4 vibrational level and for collision energies ranging from 1 μK to 100 K. It is found that, for collision energies below 3 K, inclusion of the geometric phase leads to dramatic enhancement or suppression of the reaction rates depending on the final quantum state of the HD molecule. The effect was found to be the most prominent for rotationally resolved integral and differential cross sections but it persists to a lesser extent in the vibrationally resolved and total reaction rate coefficients. However, no significant GP effect is present in the reactive channel leading to the D+H2 product or in the D+H2 (v=4,j=0) \\to HD+H reaction. A simple interference mechanism involving inelastic (nonreactive) and exchange scattering amplitudes is invoked to account for the observed GP effects. The computed results also reveal a shape resonance in the H+HD reaction near 1 K and the GP effect is found to influence the magnitude of the resonant part of the cross section. Experimental detection of the resonance may allow a sensitive probe of the GP effect in the H+HD reaction.

  9. Vision 2020. Reaction Engineering Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Klipstein, David H. [Reaction Design, San Diego, CA (United States); Robinson, Sharon [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2001-01-01

    The Reaction Engineering Roadmap is a part of an industry- wide effort to create a blueprint of the research and technology milestones that are necessary to achieve longterm industry goals. This report documents the results of a workshop focused on the research needs, technology barriers, and priorities of the chemical industry as they relate to reaction engineering viewed first by industrial use (basic chemicals; specialty chemicals; pharmaceuticals; and polymers) and then by technology segment (reactor system selection, design, and scale-up; chemical mechanism development and property estimation; dealing with catalysis; and new, nonstandard reactor types).

  10. Fundamentals of chemical reaction engineering

    CERN Document Server

    Davis, Mark E

    2012-01-01

    Appropriate for a one-semester undergraduate or first-year graduate course, this text introduces the quantitative treatment of chemical reaction engineering. It covers both homogeneous and heterogeneous reacting systems and examines chemical reaction engineering as well as chemical reactor engineering. The authors take a chemical approach, helping students develop an intuitive feeling for concepts, rather than an engineering approach, which tends to overlook the inner workings of systems and objects.Each chapter contains numerous worked-out problems and real-world vignettes involving commercia

  11. TBM pressure models: observations, theory and practice

    OpenAIRE

    Gerheim Souza Dias, Tiago; Bezuijen, Adam

    2015-01-01

    Mechanized tunnelling in soft ground has evolved significantly over the last 20 years. However, the interaction between the tunnel boring machine (TBM) and the ground is often understood through idealized concepts, focused mostly on the machine actions in detriment of the reactions from the ground. These concepts cannot be used to explain several mechanisms that have been observed during the construction of mechanized tunnels. Therefore, this paper presents the path from field observations to...

  12. Intermediates in Isotopic Exchange Reactions Involving Diborane

    International Nuclear Information System (INIS)

    By conventional mass spectrometric analysis, the self-exchange reaction of diborane was studied by using boron and hydrogen isotopes as tracers. The ratio of deuterium to boron exchange was found to be 2.8. This suggests that the reaction is not completely proceeding by exchange of BH3's as an entity, and that the mechanism is more complicated than simply a stripping reaction between diborane and a borane. It was therefore decided to attempt to get some knowledge of the intermediates that are present in diborane dissociation since they may shed light on the mechanism of the exchange. Using a specially constructed mass spectrometer of high sensitivity coupled with a flow reactor, it was possible to make a direct detection of the intermediate involved in the diborane equilibria. The intermediates BH3 and BH2 were found to be present and their ionization potentials were measured. In addition, a small amount of B3Hn was observed but the value of n could not be determined because of the weak peaks obtained. An attempt is made to interpret the self-exchange reaction of diborane in terms of these intermediates. The results suggest that diborane is in rapid equilibrium with borane (BH3). In addition, apparently diborane can also dissociate in BH2 which was about twice as abundant as BH3. The B3Hn intermediate that was observed is believed to arise from the reaction. BH3 + B2H6 -> B3H9. In applying this information to the isotopic self-exchange in diborane, it appears that the exchange cannot be going by a stripping mechanism such as BD3 + BH3 - BH3 - BD3 - BH3 + BH3, since the deuterium-to-boron isotopic ratio then should be 3. Another possible mechanism of exchange is BD3 + B2H6 ⇌ B3D3H6; the B3 complex can be pictured as a symmetrical one. If the bonds were all exactly equivalent the D/ 10B ratio would statistically become 3; however, some isotope effect may be present in the fragmentation of the complex and the ratio could deviate from 3. Another possible way in which

  13. Detection Of Concrete Deterioration By Staining

    Science.gov (United States)

    Guthrie, Jr., George D.; Carey, J. William

    1999-09-21

    A method using concentrated aqueous solutions of sodium cobaltinitrite and a rhodamine dye is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR), and to identify degraded concrete which results in a porous or semi-permeable paste due to carbonation or leaching. These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.

  14. INFLUENCE OF GLASS CULLET IN CEMENT PASTES

    Institute of Scientific and Technical Information of China (English)

    A.Karamberi; E.Chaniotakis; D.Papageorgiou; A.Moutsatsou

    2006-01-01

    The present study investigates glass and cement compatibility with a view to use glass as a cement replacement. Amber, flint and green glasses were chosen due to their prevalence in the Greek market as packaging materials. The factors under investigation were the pozzolanicity of the glass cullet, the hydration rate and the mechanical strength development of the cement pastes, as well as the expansion of the specimens due to alkali-silica reaction.Moreover, the potential enhancement of glass pozzolanic activity was examined. The results of the study were encouraging to show the potentiality of utilising glass cullet in cementitious products.

  15. Stereoselectivity in (Acyloxy)borane-Catalyzed Mukaiyama Aldol Reactions.

    Science.gov (United States)

    Lee, Joshua M; Zhang, Xin; Norrby, Per-Ola; Helquist, Paul; Wiest, Olaf

    2016-07-01

    The origin of diastereo- and enantioselectivity in a Lewis acid-catalyzed Mukaiyama aldol reaction is investigated using a combination of dispersion corrected DFT calculations and transition state force fields (TSFF) developed using the quantum guided molecular mechanics (Q2MM) method. The reaction proceeds via a closed transition structure involving a nontraditional hydrogen bond that is 3.3 kJ/mol lower in energy than the corresponding open transition structure. The correct prediction of the diastereoselectivity of a Mukaiyama aldol reaction catalyzed by the conformationally flexible Yamamoto chiral (acyloxy) borane (CAB) requires extensive conformational sampling at the transition structure, which is achieved using a Q2MM-derived TSFF, followed by DFT calculations of the low energy conformational clusters. Finally, a conceptual model for the rationalization of the observed diastereo- and enantioselectivity of the reaction using a closed transition state model is proposed. PMID:27247023

  16. Quantum-State Controlled Chemical Reactions of Ultracold KRb Molecules

    CERN Document Server

    Ospelkaus, S; Wang, D; de Miranda, M H G; Neyenhuis, B; Quéméner, G; Julienne, P S; Bohn, J L; Jin, D S; Ye, J

    2009-01-01

    How does a chemical reaction proceed at ultralow temperatures? Can simple quantum mechanical rules such as quantum statistics, single scattering partial waves, and quantum threshold laws provide a clear understanding for the molecular reactivity under a vanishing collision energy? Starting with an optically trapped near quantum degenerate gas of polar $^{40}$K$^{87}$Rb molecules prepared in their absolute ground state, we report experimental evidence for exothermic atom-exchange chemical reactions. When these fermionic molecules are prepared in a single quantum state at a temperature of a few hundreds of nanoKelvins, we observe p-wave-dominated quantum threshold collisions arising from tunneling through an angular momentum barrier followed by a near-unity probability short-range chemical reaction. When these molecules are prepared in two different internal states or when molecules and atoms are brought together, the reaction rates are enhanced by a factor of 10 to 100 due to s-wave scattering, which does not ...

  17. Chemical kinetic reaction mechanism for the combustion of propane

    Science.gov (United States)

    Jachimowski, C. J.

    1984-01-01

    A detailed chemical kinetic reaction mechanism for the combustion of propane is presented and discussed. The mechanism consists of 27 chemical species and 83 elementary chemical reactions. Ignition and combustion data as determined in shock tube studies were used to evaluate the mechanism. Numerical simulation of the shock tube experiments showed that the kinetic behavior predicted by the mechanism for stoichiometric mixtures is in good agrement with the experimental results over the entire temperature range examined (1150-2600K). Sensitivity and theoretical studies carried out using the mechanism revealed that hydrocarbon reactions which are involved in the formation of the HO2 radical and the H2O2 molecule are very important in the mechanism and that the observed nonlinear behavior of ignition delay time with decreasing temperature can be interpreted in terms of the increased importance of the HO2 and H2O2 reactions at the lower temperatures.

  18. Many-body Quantum Reaction Dynamics near the Fusion Barrier

    Directory of Open Access Journals (Sweden)

    Dasgupta M.

    2014-03-01

    Full Text Available The understanding of quantum effects in determining nuclear reaction outcomes is evolving as improved experimental techniques reveal new facets of interaction dynamics. Whilst the phenomenon of coupling-enhanced quantum tunnelling is understood to arise due to quantum superposition, the observed inhibition of fusion at energies well below the barrier is not yet quantitatively understood. Collisions involving weakly-bound nuclei, which have low energy thresholds against breakup, present further challenges. Recent coincidence measurements for reactions of weakly bound stable nuclei have not only provided a complete picture of the physical mechanisms triggering breakup, but have also shown how information on reaction dynamics occurring on time-scales of ~zepto-seconds can be obtained experimentally. These new experimental findings demand major developments in quantum models of near-barrier nuclear reactions.

  19. Many-body quantum reaction dynamics near the fusion barrier

    International Nuclear Information System (INIS)

    The understanding of quantum effects in determining nuclear reaction outcomes is evolving as improved experimental techniques reveal new facets of interaction dynamics. Whilst the phenomenon of coupling-enhanced quantum tunnelling is understood to arise due to quantum superposition, the observed inhibition of fusion at energies well below the barrier is not yet quantitatively understood. Collisions involving weakly-bound nuclei, which have low energy thresholds against breakup, present further challenges. Recent coincidence measurements for reactions of weakly bound stable nuclei have not only provided a complete picture of the physical mechanisms triggering breakup, but have also shown how information on reaction dynamics occurring on time-scales of ∼ zepto-seconds can be obtained experimentally. These new experimental findings demand major developments in quantum models of near-barrier nuclear reactions. (authors)

  20. Switching Dynamics in Reaction Networks Induced by Molecular Discreteness

    CERN Document Server

    Togashi, Y; Kaneko, Kunihiko; Togashi, Yuichi

    2006-01-01

    To study the fluctuations and dynamics in chemical reaction processes, stochastic differential equations based on the rate equation involving chemical concentrations are often adopted. When the number of molecules is very small, however, the discreteness in the number of molecules cannot be neglected since the number of molecules must be an integer. This discreteness can be important in biochemical reactions, where the total number of molecules is not significantly larger than the number of chemical species. To elucidate the effects of such discreteness, we study autocatalytic reaction systems comprising several chemical species through stochastic particle simulations. The generation of novel states is observed; it is caused by the extinction of some molecular species due to the discreteness in their number. We demonstrate that the reaction dynamics are switched by a single molecule, which leads to the reconstruction of the acting network structure. We also show the strong dependence of the chemical concentra...

  1. Is There a Minimum Electrophilicity Principle in Chemical Reactions?

    Institute of Scientific and Technical Information of China (English)

    NOORIZADEH,Siamak

    2007-01-01

    For 25 simple reactions, the changes of the hardness (△η), polarizability (△α) and electrophilicity index (△ω)and their cube-roots (△η1/3, △α1/3, △ω1/3) were calculated. It is shown that although the Maximum Hardness and Minimum Polarizability Principles are not valid for all reactions, but in most cases △ω1/3<0, whereas we always find △ω<0. Our observation impliesto this fact that for those chemical reactions in which the number of moles decreases or at least remains constant, the most stable species (reactants or products) have the lowest sum of electrophilicities. In other words "the natural direction of a chemical reaction is toward a state of minimum electrophilicity". This fact may be called Minimum Electrophilicity Principle (MEP).

  2. Reaction Networks For Interstellar Chemical Modelling: Improvements and Challenges

    CERN Document Server

    Wakelam, V; Herbst, E; Troe, J; Geppert, W; Linnartz, H; Oberg, K; Roueff, E; Agundez, M; Pernot, P; Cuppen, H M; Loison, J C; Talbi, D

    2010-01-01

    We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes -- ion-neutral reactions, neutral-neutral reactions, radiative association, and dissociative recombination -- is reviewed. Emphasis is placed on those reactions that have been identified, by sensitivity analyses, as 'crucial' in determining the predicted abundances of the species observed in the interstellar medium. These sensitivity analyses have been carried out for gas-phase models of three representative, molecule-rich, astronomical sources: the cold dense molecular clouds TMC-1 and L134N, and the expanding circumstellar envelope IRC +10216. Our review has led to the proposal of new values and uncertainties for the rate coefficients of many of the key reactions. The impact of these new data on the predicted abundances in TMC-1 and L134N is reported. Interstellar dust p...

  3. Reactions

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    2011-01-01

    construction; and 2) As a construction of a new reactive modality of the (art) museum as ‘archive of reality' - showing the outline of a cultural institution that oscillates between the instituting and institutionalizing competences of the (art) museum - between knowledge-based and experience-based exhibiting......  My concern is to understand augmentation as an emergent modality - among many others in ‘the expanding digital field' (Søndergaard M. , Transformative Creativity in the Expanded Digital Field, 2009)' - attributed to the production of contemporary art and the ‘archive of knowledge' in the (art......) museum. Augmentation, in this expanding digital field, is part of a production of new public spaces, as well as a new reality that affects and traverses art and institutions immanently and througout. The expanding digital field is transforming art and the art museum in a number of fundamental ways, a few...

  4. Reaction-subdiffusion front propagation in a comblike model of spiny dendrites.

    Science.gov (United States)

    Iomin, A; Méndez, V

    2013-07-01

    Fractional reaction-diffusion equations are derived by exploiting the geometrical similarities between a comb structure and a spiny dendrite. In the framework of the obtained equations, two scenarios of reaction transport in spiny dendrites are explored, where both a linear reaction in spines and nonlinear Fisher-Kolmogorov-Petrovskii-Piskunov reactions along dendrites are considered. In the framework of fractional subdiffusive comb model, we develop a Hamilton-Jacobi approach to estimate the overall velocity of the reaction front propagation. One of the main effects observed is the failure of the front propagation for both scenarios due to either the reaction inside the spines or the interaction of the reaction with the spines. In the first case the spines are the source of reactions, while in the latter case, the spines are a source of a damping mechanism. PMID:23944491

  5. Observer's Interface for JWST Observation Specifications

    Science.gov (United States)

    Link, Miranda; Douglas, Robert; Moriarty, Christopher; Roman, Anthony

    2016-01-01

    In support of the launch of the James Webb Space Telescope, various teams at STScI (the Space Telescope Science Institute) have collaborated on how to re-structure the view of a an observing program within the Astronomer's Proposal Tool (APT) to accommodate for the differences between HST and JWST. For HST APT programs, the structure is visit-dominant, and there is one generic form for entering observing information that spans all instruments with their required fields and options. This can result in sometimes showing irrelevant fields to the user for a given observing goal. Also, the generation of mosaicked observations in HST requires the user to manually calculate the position of each tile within the mosaic, accounting for positional offsets and the roll of the telescope, which is a time consuming process. Now, for JWST programs in APT, the description of the observations has been segregated by instrument and mode into discrete observing templates. Each template's form allows instrument specific choices and displays of relevant information. APT will manually manage the number of visits needed to perform the observation. This is particularly useful for mosaics and dithering with JWST. For example, users will select how they would like a mosaic to be tiled at the observation level, and the visits are automatically created. In this, visits have been re-structured to be purely informational; all editing is done at the observation level. These options and concepts are illustrated to future users via the corresponding poster.

  6. Hydrogen evolution from water through metal sulfide reactions

    International Nuclear Information System (INIS)

    Transition metal sulfides play an important catalytic role in many chemical reactions. In this work, we have conducted a careful computational study of the structures, electronic states, and reactivity of metal sulfide cluster anions M2SX− (M = Mo and W, X = 4–6) using density functional theory. Detailed structural analysis shows that these metal sulfide anions have ground state isomers with two bridging sulfide bonds, notably different in some cases from the corresponding oxides with the same stoichiometry. The chemical reactivity of these metal sulfide anions with water has also been carried out. After a thorough search on the reactive potential energy surface, we propose several competitive, energetically favorable, reaction pathways that lead to the evolution of hydrogen. Selectivity in the initial water addition and subsequent hydrogen migration are found to be the key steps in all the proposed reaction channels. Initial adsorption of water is most favored involving a terminal metal sulfur bond in Mo2S4− isomers whereas the most preferred orientation for water addition involves a bridging metal sulfur bond in the case of W2S4− and M2S5− isomers. In all the lowest energy H2 elimination steps, the interacting hydrogen atoms involve a metal hydride and a metal hydroxide (or thiol) group. We have also observed a higher energy reaction channel where the interacting hydrogen atoms in the H2 elimination step involve a thiol (–SH) and a hydroxyl (–OH) group. For all the reaction pathways, the Mo sulfide reactions involve a higher barrier than the corresponding W analogues. We observe for both metals that reactions of M2S4− and M2S5− clusters with water to liberate H2 are exothermic and involve modest free energy barriers. However, the reaction of water with M2S6− is highly endothermic with a considerable barrier due to saturation of the local bonding environment

  7. Application of Polarization in Particle Reactions.

    Science.gov (United States)

    Arash, Firooz

    In this dissertation we have utilized polarization phenomena in particle reactions to study the revealing features of the reaction. First, it is shown that it is impossible to design a non-dynamical null-experiment to test the time-reversal invariant. Second, the optimal formalism representation is used to determine proton-proton elastic scattering amplitudes at 579 MeV and 800 MeV. It is shown that, despite an extensive set of data at 579 MeV, the resulting amplitudes have a four-fold ambiguity. At 800 MeV, however, we managed to obtain a unique solution. Thirdly, the polarization structure of two-body reaction in a collinear configuration is investigated, and it is demonstrated that the structure becomes much simpler than it was for the general configuration. It is shown that in a collinear reaction all observables in which only one particle is polarized vanish. The results of this study are also applicable to all models in which helicity conservation holds, since they are formally identical with collinear reactions. Fourthly, an amplitude test is conducted to search for dibaryon resonances in p-p elastic scattering and it is found that at the energies around 800 MeV there is no evidence for any singlet partial wave state resonances. There exist, however, some tantalizing subliminal evidence for ('3)F(,3) resonance. This method is also applied for pion-deutron elastic scattering to pin point the effect of a dibaryon resonance. We have also given a practical guideline to carry out a complete set of experiments toward the reconstruction of pion-deutron scattering amplitudes. Fifthly, evidence for the preeminence of one-particle-exchange mechanism is p-p elastic scattering is also examined in the 300 MeV - 6 GeV/c range. Finally, a phenomenological model is developed to explain a striking feature of p-p scattering amplitudes pertaining to the amplitudes being either purely real or purely imaginary, and having three amplitudes almost equal in magnitudes and three

  8. Development of a novel fingerprint for chemical reactions and its application to large-scale reaction classification and similarity.

    Science.gov (United States)

    Schneider, Nadine; Lowe, Daniel M; Sayle, Roger A; Landrum, Gregory A

    2015-01-26

    Fingerprint methods applied to molecules have proven to be useful for similarity determination and as inputs to machine-learning models. Here, we present the development of a new fingerprint for chemical reactions and validate its usefulness in building machine-learning models and in similarity assessment. Our final fingerprint is constructed as the difference of the atom-pair fingerprints of products and reactants and includes agents via calculated physicochemical properties. We validated the fingerprints on a large data set of reactions text-mined from granted United States patents from the last 40 years that have been classified using a substructure-based expert system. We applied machine learning to build a 50-class predictive model for reaction-type classification that correctly predicts 97% of the reactions in an external test set. Impressive accuracies were also observed when applying the classifier to reactions from an in-house electronic laboratory notebook. The performance of the novel fingerprint for assessing reaction similarity was evaluated by a cluster analysis that recovered 48 out of 50 of the reaction classes with a median F-score of 0.63 for the clusters. The data sets used for training and primary validation as well as all python scripts required to reproduce the analysis are provided in the Supporting Information. PMID:25541888

  9. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

    An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.

  10. Multispecies reaction-diffusion systems

    OpenAIRE

    Aghamohammadi, A.; Fatollahi, A. H.; Khorrami, M.; Shariati, A.

    2000-01-01

    Multispecies reaction-diffusion systems, for which the time evolution equation of correlation functions become a closed set, are considered. A formal solution for the average densities is found. Some special interactions and the exact time dependence of the average densities in these cases are also studied. For the general case, the large time behaviour of the average densities has also been obtained.

  11. Recyclization reactions leading to benzimidazoles

    Energy Technology Data Exchange (ETDEWEB)

    Mamedov, Vakhid A; Murtazina, Anna M [A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences, Kazan (Russian Federation)

    2011-05-31

    The published data on the recyclization reactions that afford benzimidazoles are generalized and systematized. Both classical and new methods of benzimidazole synthesis are considered. Attention is focused on the publications over the recent 10-15 years; of the earlier publications, only those unknown to the wide circle of chemists are analyzed.

  12. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

    2000-01-01

    A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however...

  13. Reactions of ethanol on Ru

    NARCIS (Netherlands)

    Sturm, J. M.; Lee, C. J.; F. Bijkerk,

    2013-01-01

    The adsorption and reactions of ethanol on Ru(0001) were studied with temperature-programmed desorption (TPD) and reflection-absorption infrared spectroscopy (RAIRS). Ethanol was found to adsorb intact onto Ru(0001) below 100 K. From 175 K to 200 K, ethanol is converted into ethoxy groups, which und

  14. INTERFACE REACTION IN MAGNETIC MULTILAYERS

    Institute of Scientific and Technical Information of China (English)

    G.H. Yu; M.H. Li; F.W. Zhu; X.F. Cui; J.L. Jin

    2001-01-01

    Ta/NiO/NiFe/Ta multilayers were prepared by rf reactive and dc magnetron sputter-ing. The exchange coupling field (Hex) between NiO and NiFe reached 120Oe. Thecomposition and chemical states at the interface region of NiO/NiFe were studied us-ing the x-ray photoelectron spectroscopy (XPS) and peak decomposition technique. Theresults show that there are two thermodynamically favorable reactions at NiO/NiFeinterface: NiO+Fe = Ni+FeO and 3NiO+2Fe 3Ni+Fe2 O3. The thickness of thechemical reaction as estimated by angle-resolved XPS was about 1-1.5nm. These in-terrace reaction products are magnetic defects, and we believe that the Hex and thecoereivity (He) of NiO/NiFe ave affected by these defects. Moreover, the results alsoshow that there is an "intermixing layer" at the Ta/NiO (and NiO/Ta) interface dueto a thermodynamically favorable reaction: 2Ta+5NiO=5Ni+Ta2O5. This interfacereaction has an effect on the exchange coupling as well. The thickness of the "inter-mixing layer" as estimated by XPS depth-profiles was about 8-10nm.

  15. Reactants encapsulation and Maillard Reaction

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, V.

    2013-01-01

    In the last decades many efforts have been addressed to the control of Maillard Reaction products in different foods with the aim to promote the formation of compounds having the desired color and flavor and to reduce the concentration of several potential toxic molecules. Encapsulation, already app

  16. Detecting deception through reaction times

    NARCIS (Netherlands)

    B. Verschuere; K. Suchotzki; E. Debey

    2015-01-01

    Reaction times (RTs) are among the oldest measures in psychology, and remain popular in several psychology disciplines. However, they have been largely neglected as a cue for deception, reflecting the sceptic's view that RTs fall under voluntary control and are easily manipulated. From our review of

  17. Strangeness exchange reactions and hypernuclei

    International Nuclear Information System (INIS)

    Recent progress in the spectroscopy of Λ and Σ hypernuclei is reviewed. Prospects for the production of doubly strange hypernuclei at a future kaon factory are assessed. It is suggested that the (K-,K+) reaction on a nuclear target may afford an optimal way of producing the H dibaryon, a stable six quark object with J/sup π/ = O+, S = -2

  18. Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

    Science.gov (United States)

    Garland, Rebecca M.; Elrod, Matthew J.; Kincaid, Kristi; Beaver, Melinda R.; Jimenez, Jose L.; Tolbert, Margaret A.

    While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we use the aerodyne aerosol mass spectrometer (AMS) to probe the uptake of gas-phase hexanal into ammonium sulfate and sulfuric acid aerosols. While both deliquesced and dry non-acidic ammonium sulfate aerosols showed no organic uptake, the acidic aerosols took up substantial amounts of organic material when exposed to hexanal vapor. Further, we used 1H-NMR, Fourier transform infrared (FTIR) spectroscopy and GC-MS to identify the products of the acid-catalyzed reaction of hexanal in acidic aerosols. Both aldol condensation and hemiacetal products were identified, with the dominant reaction products dependent upon the initial acid concentration of the aerosol. The aldol condensation product was formed only at initial concentrations of 75-96 wt% sulfuric acid in water. The hemiacetal was produced at all sulfuric acid concentrations studied, 30-96 wt% sulfuric acid in water. Aerosols up to 88.4 wt% organic/11.1 wt% H 2SO 4/0.5 wt% water were produced via these two dimerization reaction pathways. The UV-VIS spectrum of the isolated aldol condensation product, 2-butyl 2-octenal, extends into the visible region, suggesting these reactions may impact aerosol optical properties as well as aerosol composition. In contrast to previous suggestions, no polymerization of hexanal or its products was observed at any sulfuric acid concentration studied, from 30 to 96 wt% in water.

  19. Tactile perception during action observation.

    Science.gov (United States)

    Vastano, Roberta; Inuggi, Alberto; Vargas, Claudia D; Baud-Bovy, Gabriel; Jacono, Marco; Pozzo, Thierry

    2016-09-01

    It has been suggested that tactile perception becomes less acute during movement to optimize motor control and to prevent an overload of afferent information generated during action. This empirical phenomenon, known as "tactile gating effect," has been associated with mechanisms of sensory feedback prediction. However, less attention has been given to the tactile attenuation effect during the observation of an action. The aim of this study was to investigate whether and how the observation of a goal-directed action influences tactile perception as during overt action. In a first experiment, we recorded vocal reaction times (RTs) of participants to tactile stimulations during the observation of a reach-to-grasp action. The stimulations were delivered on different body parts that could be either congruent or incongruent with the observed effector (the right hand and the right leg, respectively). The tactile stimulation was contrasted with a no body-related stimulation (an auditory beep). We found increased RTs for tactile congruent stimuli compared to both tactile incongruent and auditory stimuli. This effect was reported only during the observation of the reaching phase, whereas RTs were not modulated during the grasping phase. A tactile two-alternative forced-choice (2AFC) discrimination task was then conducted in order to quantify the changes in tactile sensitivity during the observation of the same goal-directed actions. In agreement with the first experiment, the tactile perceived intensity was reduced only during the reaching phase. These results suggest that tactile processing during action observation relies on a process similar to that occurring during action execution. PMID:27161552

  20. Analysis of reaction schemes using maximum rates of constituent steps.

    Science.gov (United States)

    Motagamwala, Ali Hussain; Dumesic, James A

    2016-05-24

    We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, rmax,i, assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of rmax,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of rmax,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps. PMID:27162366

  1. Low-temperature desulfurizing reaction with Cu-containing sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Kwang Bok; Choi, Eun Mi; Song, Yi Keun; Rhee, Young Woo [Department of Chemical Engineering, Chungnam National University, Taejeon (Korea)

    1999-10-01

    The sorbents containing Cu O as an active material were prepared and their effectiveness in desulfurization was investigated at low temperatures(350-550 degree C). M.I.5 and MnO{sub 2} were chosen as additives and SiO{sub 2} was chosen as support material. In the low temperature regeneration reaction, sulfate was formed, which could not be decomposed until regeneration temperature reached 650 degree C. Sulfidation reaction rate decreased as calcination temperature increased. Promoting effect of MoO{sub 3} was not observed throughout the sulfidation/regeneration reaction. When SiO{sub 2} content was below 25% of sorbents composition, sulfur loading of above 10% could be obtained. Mass transfer inhibition by sulfiding gas was observed for the sorbents containing no SiO{sub 2}. 9 refs., 9 figs., 4 tabs.

  2. Effect of Ligustrazine hydrochloride on coagulation reaction and inflammation reaction in single valve replacement patients with rheumatic heart disease undergoing cardiopulmonary bypass

    Institute of Scientific and Technical Information of China (English)

    陈益君

    2014-01-01

    Objective To observe the protection effect of Ligustrazine Hydrochloride(LH)on coagulation reaction and inflammation reaction in single valve replacement patients with rheumatic heart disease undergoing cardiopulmonary bypass(CPB).Methods Totally 40 patients undergoing single valve replacement were recruited in the study and randomly assigned to the two groups,the treatment group

  3. Experimental Demonstrations in Teaching Chemical Reactions.

    Science.gov (United States)

    Hugerat, Muhamad; Basheer, Sobhi

    2001-01-01

    Presents demonstrations of chemical reactions by employing different features of various compounds that can be altered after a chemical change occurs. Experimental activities include para- and dia-magnetism in chemical reactions, aluminum reaction with base, reaction of acid with carbonates, use of electrochemical cells for demonstrating chemical…

  4. GREENER REACTIONS UNDER SOLVENT FREE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Hiren M. Marvaniya

    2011-06-01

    Full Text Available The toxicity and volatile nature of many organic solvents, particularly chlorinated hydrocarbons that are widely used in huge amounts for organic reactions have posed a serious threat to the environment. Thus, design of solventless catalytic reaction has received tremendous attention in recent times in the area of green synthesis. A solvent-free or solid state reaction may be carried out using the reactants alone or incorporating them in clays, zeolites, silica, alumina or other matrices to achieve high degree of stereoselectivity in the products, to reduce byproducts, to maximize rate of reaction. We illustrate the environmentally benign approach to 1,2-Oxazine-2- oxides, Michael addition, Wohl–Ziegler reaction, Acylation, Heck reaction, Tishchenko reaction, Diels– Alder reaction, Reformatsky and Luche Reaction, Oxidative coupling Reaction, Synthesis of chalcones, Synthesis of Dihydropyrimidinones

  5. Effect of noise on reaction time for auditory signals

    Directory of Open Access Journals (Sweden)

    M.S. Prakash Rao

    1958-10-01

    Full Text Available The effect of noise on the time taken to react to pure tone signals was studied. The reaction time was found to increase with rise in the level of noise. Individual differences become more prominent at the higher noise levels. Greater fluctuation in the same individual was also observed with increase in the noise level.

  6. Nuclear phenomena in low-energy nuclear reaction research.

    Science.gov (United States)

    Krivit, Steven B

    2013-09-01

    This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.

  7. High-spin states populated in deep-inelastic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, S. [University of Surrey, Guildford (United Kingdom). Dept. of Physics; University of Payam-Noor (Iran, Islamic Republic of). Dept. of Physics; Podolyak, Zs.; Gelletly, W.; Longdown, S.; Regan, P.H.; Valiente Dobon, J.-J.; Walker, P.M. [University of Surrey, Guildford (United Kingdom). Dept. of Physics; Angelis, G. de; Axiotis, M.; Farnea, E.; Gadea, A.; Kroell, Th.; Marginean, N.; Zhang, Y.H.; Martinez, T. [Istituto Nazionali di Fisica Nucleare, Legnaro (Italy). Laboratori Nazionali di Legnaro; Bazzacco, D.; Brandolini, F.; Lunardi, S.; Ur, C.A. [Istituto Nazionali di Fisica Nucleare, Padova (Italy). Dipt. di Fisica; Bizzeti, P.G. [Istituto Nazionali di Fisica Nucleare, Firenze (Italy). Dipt. di Fisica; Broda, R. [Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Bucurescu, D.; Ionescu-Bujor, M.; Iordachescu, A. [Institute of Physics and Nuclear Engineering, Bucharest (Romania); Medina, N.H. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica. Lab. Pelletron; Quintana, B. [University of Salamanca (Spain); Rubio, B. [Instituto di Fisica Corpuscular, Valencia (Spain)

    2004-09-15

    High spin states in the neutron rich {sup 188}Os and {sup 190}Os nuclei have been populated using the {sup 82}Se + {sup 192}Os deep-inelastic reaction. The level schemes are extended up to spin I {approx_equal}21. The observed new structures are tentatively interpreted as fragments of rotational bands built on multi-quasiparticle configurations. (author)

  8. Thermal maps of gases in heterogeneous reactions

    Science.gov (United States)

    Jarenwattananon, Nanette N.; Glöggler, Stefan; Otto, Trenton; Melkonian, Arek; Morris, William; Burt, Scott R.; Yaghi, Omar M.; Bouchard, Louis-S.

    2013-10-01

    More than 85 per cent of all chemical industry products are made using catalysts, the overwhelming majority of which are heterogeneous catalysts that function at the gas-solid interface. Consequently, much effort is invested in optimizing the design of catalytic reactors, usually by modelling the coupling between heat transfer, fluid dynamics and surface reaction kinetics. The complexity involved requires a calibration of model approximations against experimental observations, with temperature maps being particularly valuable because temperature control is often essential for optimal operation and because temperature gradients contain information about the energetics of a reaction. However, it is challenging to probe the behaviour of a gas inside a reactor without disturbing its flow, particularly when trying also to map the physical parameters and gradients that dictate heat and mass flow and catalytic efficiency. Although optical techniques and sensors have been used for that purpose, the former perform poorly in opaque media and the latter perturb the flow. NMR thermometry can measure temperature non-invasively, but traditional approaches applied to gases produce signals that depend only weakly on temperature are rapidly attenuated by diffusion or require contrast agents that may interfere with reactions. Here we present a new NMR thermometry technique that circumvents these problems by exploiting the inverse relationship between NMR linewidths and temperature caused by motional averaging in a weak magnetic field gradient. We demonstrate the concept by non-invasively mapping gas temperatures during the hydrogenation of propylene in reactors packed with metal nanoparticles and metal-organic framework catalysts, with measurement errors of less than four per cent of the absolute temperature. These results establish our technique as a non-invasive tool for locating hot and cold spots in catalyst-packed gas-solid reactors, with unprecedented capabilities for testing

  9. Thermodynamics of Enzyme-Catalyzed Reactions Database

    Science.gov (United States)

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  10. Radiation Reaction on Brownian Motions

    CERN Document Server

    Seto, Keita

    2016-01-01

    Tracking the real trajectory of a quantum particle is one of the interpretation problem and it is expressed by the Brownian (stochastic) motion suggested by E. Nelson. Especially the dynamics of a radiating electron, namely, radiation reaction which requires us to track its trajectory becomes important in the high-intensity physics by PW-class lasers at present. It has been normally treated by the Furry picture in non-linear QED, but it is difficult to draw the real trajectory of a quantum particle. For the improvement of this, I propose the representation of a stochastic particle interacting with fields and show the way to describe radiation reaction on its Brownian motion.

  11. Programmability of Chemical Reaction Networks

    Science.gov (United States)

    Cook, Matthew; Soloveichik, David; Winfree, Erik; Bruck, Jehoshua

    Motivated by the intriguing complexity of biochemical circuitry within individual cells we study Stochastic Chemical Reaction Networks (SCRNs), a formal model that considers a set of chemical reactions acting on a finite number of molecules in a well-stirred solution according to standard chemical kinetics equations. SCRNs have been widely used for describing naturally occurring (bio)chemical systems, and with the advent of synthetic biology they become a promising language for the design of artificial biochemical circuits. Our interest here is the computational power of SCRNs and how they relate to more conventional models of computation. We survey known connections and give new connections between SCRNs and Boolean Logic Circuits, Vector Addition Systems, Petri nets, Gate Implementability, Primitive Recursive Functions, Register Machines, Fractran, and Turing Machines. A theme to these investigations is the thin line between decidable and undecidable questions about SCRN behavior.

  12. Determining the Theta(+) quantum numbers through the K+ p -> pi(+)K(+)n reaction

    OpenAIRE

    Hyodo, T; Hosaka, Atsushi; Oset Báguena, Eulogio

    2004-01-01

    We study the $K^+p\\to \\pi^+K^+n$ reaction with some kinematics suited to the production of the $\\Theta^+$ resonance recently observed. We show that, independently of the quantum numbers of the $\\Theta^+$, a resonance signal is always observed in the $K^+$ forward direction. In addition, we also show how a combined consideration of the strength at the peak, and the angular dependence of polarization observables can help determine the $\\Theta^+$ quantum numbers using the present reaction.

  13. The Observation of the Effect of Evidence-based Care in the Prevention of Adverse Reactions Due to Antipsychotics%循证护理在预防抗精神病药物所致的不良反应效果探讨

    Institute of Scientific and Technical Information of China (English)

    杨淑芬; 张玉娥; 邬东红

    2014-01-01

    目的:观察循证护理在预防抗精神病药物所致的不良反应中的效果。方法选取2012年6月-2012年12月该院收治的精神疾病患者共208例,根据入院顺序分为干预组和对照组,各104例。干预组采取循证护理措施进行护理,对照组采用精神科常规护理方法,对两组患者护理8周后采用不良反应症状量表对患者进行评定,并对治疗依从性进行比较。结果不良反应症状量表结果显示,干预组和对照组在实验室检查(0.98±0.33)、(1.11±0.41),神经系统反应(0.96±0.34)、(1.10±0.45)方面比较差异无统计学意义(P>0.05),其余项目比较,差异有统计学意义(P0.05), but the differences in the remaining items were significant (P<0.05). Comparison of the treatment compliance:the difference between the two groups was statistically significant (P<0.05). Conclusion Application of evidence-based care is effective in preventing the occurrence of drug adverse reactions, improving the treatment compliance of the patients, it is worthy of application in clinical care.

  14. Reaction of disodium cromoglycate with hydrated electrons

    International Nuclear Information System (INIS)

    A possible mechanism by which disodium cromoglycate (DSCG) prevents a decrease in regional cerebral blood flow but not hypotension in primates following whole body gamma-irradiation was studied. Several studies have implicated superoxide radicals (O2-.) in intestinal and cerebral vascular disorders following ischemia and ionizing radiation, respectively. O2-. is formed during radiolysis in the reaction between hydrated electrons (e-aq) and dissolved oxygen. For this reason, the efficiency of DSCG to scavenge e-q and possibly prevent the formation of O2-. was studied. Hydrated electrons were produced by photolysis of potassium ferrocyanide solutions. The rate constant, k = 2.92 x 10(10) M-1s-1 for the reaction between e-aq and DSCG was determined in competition experiments using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). This spin trap reacts rapidly with e-aq followed by protonation to yield the ESR observable DMPO-H spin adduct. The results show that DSCG is an efficient e-aq scavenger and may effectively compete with oxygen for e-aq preventing the radiolytic formation of O2-

  15. Study of an anaphylactoid reaction to acetaminophen.

    Science.gov (United States)

    Liao, Chien-Ming; Chen, Wu-Charng; Lin, Ching-Yuang

    2002-01-01

    Generalized itching, urticaria and anaphylactic shock developed in a 9-year-old girl on two separate occasions after she ingested acetaminophen. She was admitted to our hospital for observation during oral challenge. Total eosinophil counts, total serum IgE, IgA, IgG, IgM, C3, and C4, specific IgE antibodies to six common allergens, and skin prick tests to purified acetaminophen and acetylsalicylic acid (aspirin) were unremarkable. No reaction occurred on open challenge with acetylsalicylic acid and mefenamic acid. However, urticaria and itching sensation occurred 45 min after ingesting 50 mg of purified acetaminophen. Dizziness, shivering, tachycardia and fainting also developed later. These symptoms resolved after treatment with a diphenhydramine injection and intravenous infusion of normal saline. There was a marked increase in the blood histamine level after challenge. In vitro histamine release before oral challenge was also abnormally as high as 50%. In summary, she had an immediate allergic reaction to acetaminophen but was tolerant to acetylsalicylic acid. PMID:12148965

  16. Reaction of disodium cromoglycate with hydrated electrons

    Energy Technology Data Exchange (ETDEWEB)

    Carmichael, A.J.; Arroyo, C.M.; Cockerham, L.G.

    1988-01-01

    A possible mechanism by which disodium cromoglycate (DSCG) prevents a decrease in regional cerebral blood flow but not hypotension in primates following whole body gamma-irradiation was studied. Several studies have implicated superoxide radicals (O/sub 2//sup -/.) in intestinal and cerebral vascular disorders following ischemia and ionizing radiation, respectively. O/sub 2//sup -/. is formed during radiolysis in the reaction between hydrated electrons (e-aq) and dissolved oxygen. For this reason, the efficiency of DSCG to scavenge e-q and possibly prevent the formation of O/sub 2//sup -/. was studied. Hydrated electrons were produced by photolysis of potassium ferrocyanide solutions. The rate constant, k = 2.92 x 10(10) M-1s-1 for the reaction between e-aq and DSCG was determined in competition experiments using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). This spin trap reacts rapidly with e-aq followed by protonation to yield the ESR observable DMPO-H spin adduct. The results show that DSCG is an efficient e-aq scavenger and may effectively compete with oxygen for e-aq preventing the radiolytic formation of O/sub 2//sup -/..

  17. Tuberculin reaction and BCG scar

    DEFF Research Database (Denmark)

    Timmermann, Clara Amalie Gade; Biering-Sørensen, Sofie; Aaby, Peter;

    2015-01-01

    rate ratio (MRR) comparing children with a BCG scar with those without was 0.42 (95% CI = 0.19; 0.93). There was a similar tendency for TST positivity: MRR = 0.47 (95% CI = 0.14; 1.54). For LBW children who had both a positive TST reaction and a scar, the MRR was 0.22 (95% CI = 0.05; 0.87). For NBW...

  18. Cellular reactions to patterned biointerfaces

    OpenAIRE

    Schulte, Vera Antonie

    2012-01-01

    The subject of this thesis is to study cellular reactions to topographically, mechanically and biochemically tunable polymeric biomaterials. Different aspects of in vitro cell-biomaterial interactions were systematically studied with the murine fibroblast cell line NIH L929 and primary human dermal fibroblasts (HDFs). Besides a general cytocompatibility assessment of the applied materials and the quantification of cell adhesion per se, cell morphological changes (e.g. cell spreading) and intr...

  19. Magnetic resonance imaging in the evaluation of periosteal reactions

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino, E-mail: marcello@fmrp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Sa, Jose Luiz de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Oliveira, Rodrigo Cecilio Vieira de [Clinica de Diagnostico por Imagem Tomoson, Aracatuba, SP (Brazil); Engel, Edgard Eduard [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Biomecanica, Medicina e Reabilitacao do Aparelho Locomotor

    2010-07-15

    The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

  20. Dynamics of anion-molecule reactions at low energy

    International Nuclear Information System (INIS)

    Anion-molecule reactions must find their way through deeply bound entrance and exit channel complexes separated by a central barrier. This results in low reaction rates and rich dynamics since direct pathways compete with the formation of transient intermediates. In this thesis we examine the probability of proton transfer to a small anion and transient lifetimes of a thermoneutral bimolecular nucleophilic substitution (SN2) reaction at well defined variable temperature down to 8 Kelvin in a multipole trap. The observed strong inverse temperature dependence is attributed to the deficit of available quantum states in the entrance channel at decreasing temperature. Furthermore we investigate scattering dynamics of SN2 reactions at defined relative energy between 0.4 and 10 eV by crossed beam slice imaging. A weakly exothermic reaction with high central barrier proceeds via an indirect, complex-mediated mechanism at low relative energies featuring high internal product excitation in excellent quantitative agreement with a statistical model. In contrast, direct backward scattering prevails for higher energies with product velocities close to the kinematical cutoff. For a strongly exothermic reaction, competing SN2-, dihalide- and proton transfer-channels are explored which proceed by complex mediation for low energy and various rebound-, grazing- and collision induced bond rupture-mechanisms at higher energy. From our data and a collaboration with theory we identify a new indirect roundabout SN2 mechanism involving CH3-rotation. (orig.)