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Graphene has received tremendous interest in both chemical and physical fields. Among different edges of the graphene system, the zigzag edge terminated graphene nanoribbons (ZGNRs) show unique magnetic properties in the antiferromagnetic (AFM) state. However, to date, the understanding of ZGNR chemical properties is mainly based on the partial radical concept, and in previous studies, the energy differences between the ferromagnetic (FM) and AFM states are smaller than experimental evidence. Here, we report that the strongly constrained and appropriately normed functional gives a significantly larger energy difference, which matches the experimental observation. Furthermore, utilizing the energetics in the large difference case, we propose a conceptual supplement to the previous partial radical concept: the overall stabilization of the AFM state compared to the nonmagnetic (NM) state consists of two parts that affect the adsorption energy conversely. The NM-FM energy differences will strengthen the adsorption, being in line with the previous partial radical concept. The FM-AFM energy differences will instead weaken the adsorption. We perform calculations of H, OH, and LiS radical adsorption energies on ZGNRs to show that this weakening effect is numerically non-negligible: at least a ∼0.2 eV difference in the adsorption energies is found. We expect that this refinement of the partial radical concept can provide a more comprehensive understanding of the chemical properties of ZGNRs. The differences in adsorption energies for the H, OH, and LiS radicals found here lead to significant changes in the predicted reactivity of the ZGNR models. [ABSTRACT FROM AUTHOR]

Copper (Cu) remains the most important metal catalyst for the carbon dioxide reduction reaction (CO2RR) into C2 products. Due to limited evidence from in situ experiments, mechanistic studies are often performed in the framework of density functional theory (DFT), using functionals at the generalized gradient approximation (GGA) level, which have fundamental difficulties to correctly describe CO adsorption and surface stability. We employ the adiabatic connection fluctuation dissipation theorem within the random phase approximation (RPA), in combination with the linearized Poisson–Boltzmann equation to describe solvation effects, to investigate the mechanism of CO2RR on the Cu(100) facet. Qualitatively different from the DFT‐GGA results, RPA results propose the formation of *OCCHO as the potential determining step towards C2 products. The results suggest that it is important to use more accurate methods like RPA when modeling reactions involving multiple CO‐related species like CO2RR. [ABSTRACT FROM AUTHOR]

Copper (Cu) remains the most important metal catalyst for the carbon dioxide reduction reaction (CO2RR) into C2 products. Due to limited evidence from in situ experiments, mechanistic studies are often performed in the framework of density functional theory (DFT), using functionals at the generalized gradient approximation (GGA) level, which have fundamental difficulties to correctly describe CO adsorption and surface stability. We employ the adiabatic connection fluctuation dissipation theorem within the random phase approximation (RPA), in combination with the linearized Poisson–Boltzmann equation to describe solvation effects, to investigate the mechanism of CO2RR on the Cu(100) facet. Qualitatively different from the DFT‐GGA results, RPA results propose the formation of *OCCHO as the potential determining step towards C2 products. The results suggest that it is important to use more accurate methods like RPA when modeling reactions involving multiple CO‐related species like CO2RR. [ABSTRACT FROM AUTHOR]

Speech therapy can be part of the care pathway for patients recovering from comas and presenting a disorder of consciousness (DOC). Although there are no official recommendations for speech therapy follow-up, neuroscientific studies suggest that relevant stimuli may have beneficial effects on the behavioral assessment of patients with a DOC. In two case studies, we longitudinally measured (from 4 to 6 weeks) the behavior (observed in a speech therapy session or using items from the Coma Recovery Scale—Revised) of two patients in a minimally conscious state (MCS) when presenting music and/or autobiographical materials. The results highlight the importance of using relevant material during a speech therapy session and suggest that a musical context with a fast tempo could improve behavior evaluation compared to noise. This work supports the importance of adapted speech therapy for MCS patients and encourages larger studies to confirm these initial observations. [ABSTRACT FROM AUTHOR]

Despite the wide applications, the ab initio modeling of the ceria based catalyst is challenging. The partial occupation in the 4f orbitals creates a fundamental challenge for commonly used density functional theory (DFT) methods, including semilocal functionals with Hubbard U correction to force localization and hybrid functionals. In this work, we benchmark the random phase approximation (RPA) for ceria surface properties, including surface energy and hydrogenation energy, compared to the results utilizing the DFT + U approach or hybrid functionals. We show that, for the latter approaches, different surface properties require opposite directions of parameter tuning. This forms a dilemma for the parameter based DFT methods, as the improvement of a certain property by tuning parameters will inevitably lead to the worsening of other properties. Our results suggest that the parameter-free many-body perturbation theory methods exemplified by RPA are a promising strategy to escape the dilemma and provide highly accurate descriptions, which will allow us to better understand the catalytic reactions in ceria related systems. [ABSTRACT FROM AUTHOR]

The inclusion of non-local interactions is one of the large challenges in density functional theory. Very promising methods are the vdW-DF2 and BEEF-vdW functionals, which combine a semilocal approximation for exchange interactions and a non-local correlation expression. In this work we apply those functionals to model the adsorption of short alkanes in the zeolite SSZ-13. Even though results for energetics are improved with respect to other vdW-DF based methods, we still find a comparatively large error compared to high-level calculations. These errors result from approximations in the determination of the dielectric function and of the van der Waals kernel. The insights presented in this work will help to understand the performance not only of vdW-DF2 and BEEF-vdW, but all vdW-DF based functionals in various chemically or physically important systems. [ABSTRACT FROM AUTHOR]

Determining structures of supported sub‐nanometer catalytic clusters is important for finding binding sites, active sites, and reaction mechanisms. In realistic conditions, the cluster may be covered with adsorbed reactants and intermediates, which strongly affect the structure of the cluster compared to the low coverage regime. The global optimization of supported adsorbate‐covered clusters is not possible with existing methods. We present a customized Basin Hopping (BH) approach, with a core (metal cluster)‐shell (adsorbates) separation scheme, and perform first applications to the search of low‐energy isomers of Pt7/α‐Al2O3 at high hydrogen coverage (10H). The presence of adsorbates significantly alters the low‐energy isomers compared to bare Pt7/α‐Al2O3. Molecular dynamics simulations additionally show the different time‐scales associated with the mobility of H and Pt atoms. The revised BH method with core‐shell separation presents key advantages for the structural exploration of adsorbate‐covered supported catalysts, relevant to realistic catalytic conditions. [ABSTRACT FROM AUTHOR]

Revisions TKAs are being completed with uncemented constructs more frequently. We hypothesized that tantalum cones could be an efficient carrier of antibiotics in uncemented procedures. We aimed to compare the release of vancomycin between (i) tantalum and smooth stainless cylinders; (ii) different concentrations of vancomycin; and (iii) different durations of bathing. Specifically designed tantalum cylinders were bathed in a vancomycin solution with various durations of baths. We investigated rinses between each interval as well as the dose of vancomycin. Vancomycin concentrations were determined in each group by fluorescence polarization immunoassay at different intervals (1 h, days 1, 2, 3, 5). At 1 h, the mean vancomycin concentration for the 1‐hour soaking group was 3,172 μg/ml, whereas mean concentration for the smooth stainless steel group was 39.37 μg/ml (p < 0.001). The rinsing group showed a significantly lower concentration at 1 h and 1 day (p < 0.05). The 2‐gram vancomycin group showed no difference at days 1, 2, and 3 compared to the 1‐hour group. The 5, 15, and 30‐minute bathing groups showed significantly lower vancomycin concentrations at all‐time points. All vancomycin concentrations at day 3 were superior to the minimal inhibitory concentration of Staphyloccocus aureus. The mean concentration of vancomycin depends on the material, duration of bathing, the rinsing effect, and the drug dose. Our in‐vitro study is the first to show that porous tantalum cylinders allow antibiotic carriage and progressive release. If appearing in vivo, in a similar extent, this intrinsic property might be useful to prevent and/or treat peri‐prosthetic joint infection. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:308–312, 2019. [ABSTRACT FROM AUTHOR]

Reactivity studies on catalytic transition metal clusters are usually performed on a single global minimum structure. With the example of a Pt13 cluster under a pressure of hydrogen, we show from first-principle calculations that low energy metastable structures of the cluster can play a major role for catalytic reactivity and that hence consideration of the global minimum structure alone can severely underestimate the activity. The catalyst is fluxional with an ensemble of metastable structures energetically accessible at reaction conditions. A modified genetic algorithm is proposed to comprehensively search for the low energy metastable ensemble (LEME) structures instead of merely the global minimum structure. In order to reduce the computational cost of density functional calculations, a high dimensional neural network potential is employed to accelerate the exploration. The presence and influence of LEME structures during catalysis is discussed by the example of H covered Pt13 clusters for two reactions of major importance: hydrogen evolution reaction and methane activation. The results demonstrate that although the number of accessible metastable structures is reduced under reaction condition for Pt13 clusters, these metastable structures can exhibit high activity and dominate the observed activity due to their unique electronic or structural properties. This underlines the necessity of thoroughly exploring the LEME structures in catalysis simulations. The approach enables one to systematically address the impact of isomers in catalysis studies, taking into account the high adsorbate coverage induced by reaction conditions. [ABSTRACT FROM AUTHOR]

Pseudoaneurysms of the lower limb are rare and frequently iatrogenics complications. Closed traumas are likely to generate lesions of the arterial wall, which generally become symptomatic at a later stage. The diagnosis of such vascular lesion is difficult because the symptomatology and the onset can be delayed. We herein report the case of a 15-year-old patient in whom the diagnosis of pseudoaneurysm of the anterior tibial artery was made 5 months after a non-displaced closed fracture of the tibial shaft. The radiographs were evocative of a malignant bone tumor. The study of vessels by a contrast-enhanced CT-scan enabled us to diagnose the pseudoaneurysm. Before the occurrence of late onset swelling, a history of trauma must be sought, even old. [ABSTRACT FROM AUTHOR]

Understanding the fundamental properties of the Cu-exchanged zeolite SSZ-13, a catalyst for the selective catalytic reduction of nitrous oxides in the presence of ammonia, is a major challenge. Recent results for vibrational spectroscopy show that the active Cu centers are not static at room temperature, but change their coordination regularly when probe molecules are adsorbed. In this work we model the movement of bare Cu cations in SSZ-13 at room temperature (300 K) using ab-initio molecular dynamics simulations. We find that Cu cations also change their coordination without adsorbent. We identify different coordinations for different oxidation states and analyze their distribution in dependence on the local Al position. The results in this work show that this thermal motion of the cation is a general feature, which probably influences the interpretation of various characterization methods as well as reaction path analysis. In the future it will be interesting to see which conditions have to be fulfilled that similar phenomena can also be observed for other systems. [ABSTRACT FROM AUTHOR]

Kupfer-ausgetauschte SSZ-13-Zeolithe sind sehr effiziente Materialien für die selektive katalytische Reduktion von NOx mit Ammoniak (deNOx-SCR). Die Charakterisierung der Verteilung der Kupfer-Zentren in solchen Materialien ist von größter Bedeutung, um deren Aktivität zu verstehen. In dieser Studie haben wir Infrarotspektren von NO adsorbiert an Kupfer-Zentren mittels Ab-initio-Molekulardynamiksimulationen modelliert. Für die meisten Zentren haben wir komplexe Infrarotspektren mit mehreren Peaks gefunden, die durch thermische Bewegung der Kationen und der Adsorbate verursacht werden. Wir konstruierten ein Spektrum eines spezifischen Katalysators bei endlicher Temperatur, welches exzellent mit Literaturdaten übereinstimmt. Die Resultate ermöglichen eine Zuordnung der aktiven und inaktiven Zentren für die deNOx-SCR. Unseres Wissens ist dies die erste Arbeit, die über solch komplexe Spektren für einzelne adsorbierte Moleküle an einzelnen aktiven Zentren in heterogenen Katalysatoren berichtet. Wir gehen davon aus, dass ähnliche Effekte auch in einer Vielzahl anderer Systeme mit beweglichen aktiven Zentren zu finden sind. [ABSTRACT FROM AUTHOR]

With increasing concern about energy shortage and environmental protection, improving engine fuel economy and reducing exhaust emissions have become major research topics in combustion and engine development. Hythane (a blend of hydrogen H2 and natural gas NG) has generated a significant interest as an alternative fuel for the future. This paper describes an experimental study of the effects of CO2 addition on the stability of a turbulent jet diffusion NG-H2 flame. The mole fraction of hydrogen (% H2) in NG-H2 mixture was varied from 0% to 50%. The equivalence ratio of the hythane/CO2/air mixture was kept at stoichiometry. The results show that the lift-off height increases with the addition of CO2 at various % H2 content in hythane. However, we observe that with 20% H2, we can obtain a stable flame diluted with 40% CO2, while for 0% H2, the flame is blown out above 20% CO2. This means that the limits of flame blowing out are pushed with the additions of H2. Moreover, the results show that for %H2 content in NG-H2 fuel up to 10%, the addition of CO2 could produce lifted flame if the % CO2 is low. At higher % CO2 dilution, flame would remain attached until blow-out. This is mainly due to the fact that the dilution leads to ejection velocities very high but reactivity of the mixture does not change so the flame tends to stretch. [ABSTRACT FROM AUTHOR]

The evolution of anti-pollution standards and the optimization of combustion efficiency push the development of new fuels with high energy efficiency. It is necessary to develop new alternative fuel to improve the efficiency of conventional systems, reduce emissions (NO x , SO x , soot particles) and recover for its materials. A new fuel called bio-hythane, a mixture of natural gas up to 20% hydrogen and up to 50% Carbone dioxide, from the recovery of the waste from households and agriculture, via suitable digesters provides a source of renewable energy and usable, is a very interesting solution to improve emission standards and optimization of the combustion chambers. This experimental study is led in a non-reacting configuration and in combustion in order to focus on the effects of hydrogen addition and CO 2 dilution in the fuel on the velocity profiles, the turbulence intensity and the turbulent kinetic energy. From PIV measurements the results show that from the velocity and fluctuations profiles the high diffusivity and the low density of hydrogen allow bio-hythane jet to spread more efficiency in the combustion. The combustion decreases the entrainment of the ambient fluid and raises the viscosity of the flow, leading to an increase of the longitudinal velocity along the bio-hythane jet and a reduction of the turbulence in comparison with non-reacting configuration. The Carbone dioxide addition reduces the fall of the turbulence because the temperature of the flame is less important. Effects of hydrogen and CO 2 are also highlighted by analysis of turbulent kinetic energy along the bio-hythane. [ABSTRACT FROM AUTHOR]

Alumina supported Pt nanoclusters under a hydrogen environment play a crucial role in many heterogeneous catalysis applications. We conducted grand canonical genetic algorithm simulations for supported Pt8 clusters in a hydrogen gas environment to study the intracluster, cluster-support, and cluster-adsorbate interactions. Two alumina surfaces, α-Al2O3(0001) and γ-Al2O3(100), and two conditions, T = 600 °C, p H 2 = 0.1 bar and T = 25 °C, p H 2 = 1.0 bar, were considered corresponding to low and high hydrogen chemical potential μH, respectively. The low free energy ensemble of Pt8 is decorated by a medium (2–12 H), respectively, high (20–30 H), number of hydrogen atoms under equilibrium at low μH, respectively, high μH, and undergoes different morphological transformations on the two surfaces. On α-Al2O3(0001), Pt8 is mostly 3D but very fluxional in structure at low μH and converts to open one-layer 2D structures with minimal fluxionality at high μH, whereas on γ-Al2O3(100), the exact opposite occurs: Pt8 clusters present one-layer 2D shapes at low μH and switch to compact 3D shapes under high μH, during which the Pt8 cluster preserves moderate fluxionality. Further analysis reveals a similar Pt–Pt bond length increase when switching from low μH to high μH on both surfaces although morphological transformations are different. Electronic structure analysis shows the existence of bonding interactions between Pt and Lewis acidic Al3+ sites along with the Pt–O interaction, which implies the necessity to include Al neighbors to discuss the electronic structure of small Pt clusters. [ABSTRACT FROM AUTHOR]

We report the size‐dependent activity and stability of supported Pt1,4,7,8 for electrocatalytic hydrogen evolution reaction, and show that clusters outperform polycrystalline Pt in activity, with size‐dependent stability. To understand the size effects, we use DFT calculations to study the structural fluxionality under varying potentials. We show that the clusters can reshape under H coverage and populate an ensemble of states with diverse stoichiometry, structure, and thus reactivity. Both experiment and theory suggest that electrocatalytic species are hydridic states of the clusters (≈2 H/Pt). An ensemble‐based kinetic model reproduces the experimental activity trend and reveals the role of metastable states. The stability trend is rationalized by chemical bonding analysis. Our joint study demonstrates the potential‐ and adsorbate‐coverage‐dependent fluxionality of subnano clusters of different sizes and offers a systematic modeling strategy to tackle the complexities. [ABSTRACT FROM AUTHOR]

We report the size‐dependent activity and stability of supported Pt1,4,7,8 for electrocatalytic hydrogen evolution reaction, and show that clusters outperform polycrystalline Pt in activity, with size‐dependent stability. To understand the size effects, we use DFT calculations to study the structural fluxionality under varying potentials. We show that the clusters can reshape under H coverage and populate an ensemble of states with diverse stoichiometry, structure, and thus reactivity. Both experiment and theory suggest that electrocatalytic species are hydridic states of the clusters (≈2 H/Pt). An ensemble‐based kinetic model reproduces the experimental activity trend and reveals the role of metastable states. The stability trend is rationalized by chemical bonding analysis. Our joint study demonstrates the potential‐ and adsorbate‐coverage‐dependent fluxionality of subnano clusters of different sizes and offers a systematic modeling strategy to tackle the complexities. [ABSTRACT FROM AUTHOR]

This article describes an experimental study on solid olive residue (olive cake) combustion in form of pulverized jet. This is a contribution to the valorization of olive residue as a source of renewable energy available in the majority of mediterranean countries. A sample of olive cake from Tunisian origin is prepared for the experiment; this sample is crushed, dried and sifted in order to obtain the desired particles form. A new burner made up of a coaxial cylindrical tube is especially designed and fabricated. In order to start the combustion of olive cake and maintain the main flame, two types of pilot flame were used: a central premixed flame of methane/oxygen and an annular diffusion flame of methane. This paper shows the conditions for an efficient olive cake burner operation in free air. The effects of particle size and pilot flame position have been discussed. The olive cake combustion is possible only with particles at a size below 200 μm. Moreover, the combustion maintained by the annular pilot flame ensures better burning conditions than the central pilot flame. Finally, the inserted preheating system has improved the olive cake combustion. [ABSTRACT FROM AUTHOR]

A Lagrangian-Eulerian model for the dispersion of solid particles in sudden-expansion flows is reported and validated. The fluid was calculated based on the Eulerian approach by solving the Navier-Stokes equations. A Lagrangian model is also applied, using a Runge-Kutta method to obtain the particle trajectories. The effect of fluid turbulence upon particle dispersion is taken into consideration through a statistical model. The predicted axial mean velocity and turbulent kinetic energy of both phases agree well with experimental data reported by Sommerfield. [ABSTRACT FROM AUTHOR]

With 6 figures Summary A detailed description of the nasal cavity and paranasal sinuses in clinically normal cats using magnetic resonance imaging (MRI) is presented. The heads of seven normal cats were imaged using a 1.5-T MR unit and two sequences spin echo (SE) T1-weighted and fast spin echo (FSE) T2-weighted. Eighteen relevant MR scans were taken in the transverse (12 scans) and dorsal (six scans) planes. Anatomical structures were identified and labelled using anatomical texts, sectioned specimen heads and previous studies. MR scans revealed the soft-tissue structure of the head. Identified relevant anatomical structures seen on MRI will assist clinicians to better understand MR images and evaluate pathological conditions that affect the nasal region. [ABSTRACT FROM AUTHOR]

Abstract: 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(111) 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(111), 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. [Copyright &y& Elsevier]

The modeling of HIV-1 plays a crucial role in the understanding of its reactivity and its interactions with specific drugs. In this work, we propose a medium sized model to test the ability of a variety of quantum chemistry approaches to provide reasonable geometric parameters and energetics for this system. Although our model is large enough to include the main polarizing groups of the active site, it is small enough to be used within full quantum studies up to the second order Møller–Plesset (MP2) level with extrapolations to coupled cluster CCSD(T) level. These high level calculations are used as reference to assess the ability of electronic structure methods (semiempirical and DFT) to provide accurate geometries and energies for the HIV-1 protease reaction. All semiempirical methods fail to describe the geometry of the protease active site. Within DFT, pure generalized gradient approximation (GGA) functionals have difficulty in reproducing the reaction energy and underestimate the barrier. Hybrid and/or meta GGA approaches do not yield a consistent improvement. The best results are obtained with hybrid GGA B3LYP or X3LYP and with hybrid meta GGA functionals with a fraction of exact exchange around 30–40%, such as M06, B1B95, or BMK functionals. On the basis of these results, we propose an accurate and computationally efficient strategy, employing quantum chemistry methods. This is applied here to study the protonation state of the reaction intermediate and could be easily used in further QM/MM studies. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of flow development and structure on a separated jet burner in reacting and non-reacting flows. Effects of deflection jets in an aligned configuration of three round jets are emphasized. The idea is based on the confinement of a central jet of fuel by two side jets of oxygen to improve mixing, to control flame stability, and to reduce pollutant emissions. The fields of mean velocity and fluctuation intensity were measured using Particle Image Velocimetry. The deflection of jets has a considerable effect on the dynamic behavior and on the flame characteristics. Results showed that the deflection of jets favors mixing and accelerates merging and combining of jets to a single one. Measurements in reacting flow showed a high influence of combustion on dynamic fields. Compared to non-reactive case, in combustion, larger radial expansion and higher velocity were observed, particularly, above the stabilization point of the flame. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the role of theoretical chemistry in the catalysis of metal and solid surface with surface organometallic chemistry. It describes the mechanisms of interaction between the surface organometallic complex and a solid surface. It mentions that the study has brought in insights on mechanism of formation, nature of bonding with the surface, and structure of the surface organometallic complex.

Abstract: The active control of oxy-fuel flames from burners with separated jets is investigated. The control system consists of four small jet actuators, placed tangential to the exit of the main jets to generate a swirling flow. These actuators are able to modify the flow structure and to act on mixing between the reactants and consequently on the flame behavior. The burner (25kW) is composed of separated jets, one jet of natural gas and one or two jets of pure oxygen. Experiments are conducted with three burner configurations, according to the number of jets, the jet exit velocities, and the separation distance between the jets. OH chemiluminescence measurements, particle image velocimetry, and measurements of NO x emissions are used to characterize the flow and the flame structure. Results show that the small jet actuators have a significant influence on the behavior of jets and the flame characteristics, particularly in the stabilization zone. It is shown that the control leads to a decrease in lift-off heights and to better stability of the flame. The use of jet actuators induces high jet spreading and an increase in turbulence intensity, which improves the mixing between the reactants and the surrounding fluid. Pollutant measurements show important results in terms of NO x reductions (up to 60%), in particular for low swirl intensity. The burner parameters, such as the number of jets and the spacing between the jets, also impact the flame behavior and NO x formation. [Copyright &y& Elsevier]

Abstract: The effect of solid particles on the flow characteristics of axisymmetric turbulent coaxial jets for two flow conditions was studied. Simultaneous measurements of size and velocity distributions of continuous and dispersed phases in a two-phase flow are presented using a Phase Doppler Anemometry (PDA) technique. Spherical glass particles with a particle diameter range from 102 to 212μm were used in this two-phase flow, the experimental results indicate a significant influence of the solid particles and the Re on the flow characteristics. The data show that the gas phase has lower mean velocity in the near-injector region and a higher mean velocity at the developed region. Near the injector at low Reynolds number (Re=2839) the presence of the particles dampens the gas-phase turbulence, while at higher Reynolds number (Re=11893) the gas-phase turbulence and the velocity fluctuation of particle-laden jets are increased. The particle velocity at higher Reynolds number (Re=11893) and is lower at lower Reynolds number (Re=2839). The slip velocity between particles and gas phase existed over the flow domain was examined. More importantly, the present experiment results suggest that, consideration of the gas characteristic length scales is insufficient to predict gas-phase turbulence modulation in gas-particle flows. [Copyright &y& Elsevier]

Abstract: A periodic DFT approach was used to investigate ethene metathesis on a molybdena-alumina catalyst. Ten potential monomeric Mo-methylidene centers variously located on the (100) and (110) surfaces of γ-alumina were modeled. The Mo sites differed from one another in terms of geometry, the number and type of Moh name="sbnd" />Al linkages, and the number of free MoThe thermodynamic stability of the Mo-methylidene species was compared over a wide range of temperatures, taking into account the hydration state of the surface. Depending on water vapor pressure, structures bonded differently to the surface are stable. Moreover, the Mo sites on (110) γ-alumina are more stable than their analogues located on the (100) face. The pathways of ethene metathesis proceeding on the Mo-methylidene centers also were studied. The various Mo species demonstrate varying activity. Most of the Mo-methylidene centers are reactive with ethene and form molybdacyclobutane complexes, which can exist as two coordination isomers with possible interconversion. In many cases, the molybdacyclobutane species are significantly more stable than the reactants. Thus, metallacycle opening to restore carbene and olefin is the rate-limiting step for ethene metathesis. The large majority of the Mo sites, although reactive with ethene, are blocked at the molybdacyclobutane step, and their catalytic reactivity is small at room temperature. Only a small minority of sites are catalytically active. It is concluded that the most active site is located on the (100) surface and is stable in dehydrated conditions. At higher temperatures, however, other Mo species can be active in olefin metathesis. [Copyright &y& Elsevier]

Malignant tumours of the mammary gland in the female cat metastasize, especially through the lymphatic system. However, the anatomical knowledge of this system in cats is not sufficient to develop a reasoned model for the extirpation of these glands in the case of malignant tumours. A study of the topography of the collector vessels in 50 female cats was conducted by indirect injection in vivo of India ink inside the mammary parenchyma. All the lymph nodes were controlled by microscopic examination and lymph vessels were examined after clearing. The success rate of the colouration of the lymph vessels was 76.4%. Clearing showed several principal routes of drainage, different for each gland. Contrary to the presentation observed in the bitch, no evidence existed in any of the 65 cases of lymphatic plexuses connecting the two mammary glands of each row in the female cat. The result of this study is in favour of the development of a new model for the surgical extirpation of mammary tumours in cats. [ABSTRACT FROM AUTHOR]

Abstract: Oxy-fuel combustion in separated-jet burners has been proven to increase thermal efficiency and to have a potential for NOx emission reduction. This paper presents an investigation into confined, turbulent, oxy-flames generated by a burner consisting of a central natural gas jet surrounded by two oxygen jets. The study is focused on the identifying the influence of burner parameters on the flame characteristics and topology, namely stability, lift-off height and flame length. The effects of the natural gas and oxygen jet exit velocities, the distance separating the jets and the deflection of oxygen jets towards the natural gas jet are examined. The OH chemiluminescence. Results show that the lift-off heights increase when jet exit velocities and the distance separating the jets are increased. The deflection of oxygen jets decreases the lift-off height and increases the volume of flame in the transversal plane. The flame length increases principally with the oxygen exit velocity and the separation distance, and decreases considerably when the angle of oxygen jets is increased. [Copyright &y& Elsevier]

The article discusses the effects of the introduction of economic reforms in New Zealand from 1984 to 1996, such as opening the country's economy and the implementation of deregulation laws to entrepreneurship. It tries to understand the context in which the reforms took place. It also compares the country's economic performance with Ireland's. Finally, the article gives few recommendations on how to create a progressive economy through the implementation of government reforms that does not go beyond what is considered the standard norm.

In a recent priority communication [M. Digne et al., J. Catal. 211 (2002) 1], we proposed the first ab initio constructed models of γ-alumina surfaces. Using the same density-functional approach, we investigate in further detail the acid–basic properties of the three relevant γ-alumina (100), (110), and (111) surfaces, taking into account the temperature-dependent hydroxyl surface coverages. The simulations, compared fruitfully with many available experimental data, enable us to solve the challenging assignment of the OH-stretching frequencies, as obtained from infrared (IR) spectroscopy. The precise nature of the acid surface sites (concentrations and strengths) is also determined. The acid strengths are quantified by simulating the adsorption of relevant probe molecules such as CO and pyridine in correlation with surface electronic properties. These results seriously challenge the historical model of a defective spinel for γ-alumina and establish the basis for a more rigorous description of the acid–basic properties of γ-alumina. [Copyright &y& Elsevier]

Through an interplay between classical dynamic at room temperature (RT) and static STM simulations of a given adsorbate, we set up the calculation of an STM contrast acquired at finite temperature. We apply this new procedure on the model case of a molecular poison corrupting Pt catalysts. Despite significant oscillations in the time evolution of the poison coordinates, the dynamic structure is found identical to the equilibrium geometry. Similarly, the RT STM image determined over averaging along the trajectory is undistinguishable from the frozen image. In this context, allowing for thermal excitation of a chemisorbed moiety does not appreciably change its STM contrast. [Copyright &y& Elsevier]

In this study, the adsorption and the reactive properties of α-β-unsaturated aldehydes are studied by means of density functional calculations (DFT) on two well-defined Pt&z.sbnd;Sn alloy surfaces, p(2×2) Pt3Sn(111) and (√ of 3×3×√ of 3 )R30° Pt2Sn(111). First the electronic structure of the bulk alloys is determined: a charge transfer occurs from Sn to Pt, the work function decreases, and the d-band center is shifted away from the Fermi level. Then various adsorption structures of acrolein (propenal), crotonaldehyde (2-butenal), and prenal (3-methyl, 2-butenal) are considered on the two alloys. The results are compared with those obtained on Pt(111). A large decrease of the adsorption energies is observed for the alloys. For acrolein, there is almost no change in the best adsorption modes, the adsorption through the C&z.dbnd;C bond being predominant. This explains why the selectivity of the acrolein hydrogenation is not changed much when Pt&z.sbnd;Sn alloys and Pt are compared. For prenal on the contrary, only the atop mode is stable on the alloys, whereas a structure parallel to the surface is the most stable one on Pt. This explains the modified reaction selectivity with a larger amount of unsaturated alcohol in the products in the case of the Sn alloys. [Copyright &y& Elsevier]

In the present work, the role of the pyroglutamic acid as a chiral auxiliary in the hydrogenation of o-toluic acid and 2-methylnicotinic acid on the Rh(111) surface has been investigated by using periodical density functional theory. The pyroglutamic acid, indeed, allows the adsorption of the aromatic ring by only one side of the ring plane. This effect is observed for both molecules. In the case of the benzoyl ring, the selectivity should be high on a perfectly flat metallic surface. It is, however, limited in practice by the presence of edges, especially in the case of small catalytic particles. On the other hand, in the case of a nicotinyl ring, the presence of a lone pair of the nitrogen atom has a great influence on the reduction of the diastereomeric excess. The NH group, formed from the partial hydrogenation of the nicotinyl ring, interacts strongly with the surface, preventing the influence of the chiral auxiliary. [Copyright &y& Elsevier]

High-resolution scanning tunneling microscopy (STM) images at 5 K, simultaneously resolving the molecular adsorbate and the honeycomb structure of the well-defined Ag{111}-p(4 × 4)+Ag[sub 1.83]O substrate, assign the adsorption site for ethene on the silver oxide surface. Ethene molecules are exclusively adsorbed above a particular subset of Ag[sup δ+] sites in the hexagonal rings of the oxide. Extensive density functional theory (DFT) stab calculations confirm that this is the most stable site, with an adsorption energy of 0.4 eV (39 kJ mol[sup -1]). Adsorption is accompanied by a large deformation of the hexagonal oxide ring and a significant increase in the C-C bond length. STM image simulations provide qualitative agreement with the experimental images, and the molecular orientation is discussed with the help of simple molecular orbital arguments. [ABSTRACT FROM AUTHOR]

Various adsorption structures of acrolein (propenal), crotonaldehyde (2-butenal), and prenal (3-methyl-2-butenal) on Pt(111) are compared by means of first-principle density functional theory calculations (DFT). Methyl substituents are added one by one at the C1 carbon of the C&z.dbnd;C–C&z.dbnd;O frame and the substitution induces a general decrease in the adsorption energy. Over a large range of coverages, acrolein shows its main interaction with the surface with the C&z.dbnd;C bond, with an eventual additional weak interaction with the oxygen atom. This could clearly result in a predominant hydrogenation of the C&z.dbnd;C bond, as was seen experimentally. The influence of the substituents is subtle in the case of crotonaldehyde but clear for prenal. In that case, at low coverage a flat adsorption mode by both the C&z.dbnd;C and the C&z.dbnd;O bonds is favored. This larger implication of the C&z.dbnd;O bond in the adsorption is a first explanation for the higher selectivity in unsaturated alcohol during the hydrogenation of prenal compared with acrolein. Additionally, if high coverage is considered, the prenal molecule is too large to keep a flat adsorption mode and it can switch to a vertical geometry, interacting with the surface by the oxygen atom, while acrolein remains bonded by the C&z.dbnd;C bond. Such a vertical structure prevents C&z.dbnd;C hydrogenation and could also explain the increased selectivity to unsaturated alcohol. [Copyright &y& Elsevier]

Despite numerous experimental studies devoted to the acid–base properties of γ-alumina, the precise nature of surface acid sites remains unsolved. Using density functional (DFT) calculations, we propose realistic models of γ-alumina (110) and (100) surfaces accounting for hydroxylation/dehydroxylation processes induced by temperature effects. The vibrational analysis, based on DFT calculations, leads to an accurate assignment of the OH stretching frequencies observed by infrared (IR) spectroscopy. The extension to chlorinated surfaces, which brings new insights into the understanding of the role of dopes, is also addressed. [Copyright &y& Elsevier]

In the present work the dissociation of the trichloroethene on the PdCu(110) surface has been investigated by applying ab initio periodic density functional theory. The reaction steps, intermediates and transition states of this reaction have been identified. Two different mechanisms have been studied, starting from the most stable adsorption modes of trichloroethene (di-σ structures). Regarding the reaction path, all intermediate steps are exothermic. In addition, all activation energies are relatively small (<40 kJ mol−1). Therefore, this reaction is shown to be kinetically and thermodynamically favorable on this surface. From the intermediate steps of both mechanisms, it was possible to attain additional information about dechlorination reactions, for the other chloroethene molecules (dichloro and chloro). There is good evidence that the intermediates and transition states for the dechlorination reaction of these molecules have a similar configuration on the PdCu surface. A detailed study of the transition states indicated that the activation energy of the dissociation step increases with the rebonding energy of chlorine on the surface, which is a common fragment to all different transition states. This also confirms that these transition state are “early” ones. A simple kinetic model has been constructed with the elementary step rate constants evaluated from the calculations. The reactional system has been shown to be very complex. Most of all intermediates are present on the surface simultaneously, in accordance with experimental studies. [Copyright &y& Elsevier]

Investigates the interaction of the different bitartrate isomers on the copper(110) surface. Possible adsorption patterns of the bitartrate isomers; Role of the adsorbed bitartrate molecules in the chiral pattern formation; Bond order conservation principle; Molecular distortions in the C(2)-C(3) bond; Stability of the interaction.

Discusses the theoretical calculations of scanning tunneling microscopy (STM) images of atomic and molecular adsorbates. Non-relation of the bumps and shapes on the STM image with the actual lateral positions of atoms; Difficulty of identifying the nature of the species corresponding to the pattern observed in the STM image.

Studies four round turbulent jets of hydrogen-nitrogen mixtures discharging into slow air coflow. Mean and fluctuation of the velocity components; Radial profiles of mean density; Investigation of self-similar behavior by using a local effective jet diameter that accounts for the strong density variations in the near development field.

The present paper describes the effects of hydrogen addition and carbon dioxide dilution in the natural gas on the velocity profiles and on the turbulent quantities (integral scale and Kolmogorov scale) in a cylindrical burner. The hydrogen content in the fuel is varied from 0 to 20% in volume, and the volume of carbon dioxide is varied between 0 and 50%. The velocity fields and the root mean square value of velocity are determined by the particle image velocimetry technique in the reacting flow. The concentrations of CO and NO are found using the corresponding analyzers. The turbulent quantities are determined by a numerical method. The results show that the absence of hydrogen and the carbon dioxide content greater than 20% lead to flame blow-out. Therefore, the flame is hooked to the burner if hydrogen is added. In this study, with hydrogen addition, the difference in the maximum velocity () along the bio-hythane jet is less important far from the burner due to the low density and high molecular diffusivity of hydrogen. The studies of the root mean square values of two velocity components ( and ) indicate that turbulence is more important for the component. [ABSTRACT FROM AUTHOR]

Preterm birth (PTB) represents 15 million births every year worldwide and is frequently associated with maternal/fetal infections and inflammation, inducing neuroinflammation. This neuroinflammation is mediated by microglial cells, which are brain-resident macrophages that release cytotoxic molecules that block oligodendrocyte differentiation, leading to hypomyelination. Some preterm survivors can face lifetime motor and/or cognitive disabilities linked to periventricular white matter injuries (PWMIs). There is currently no recommendation concerning the mode of delivery in the case of PTB and its impact on brain development. Many animal models of induced-PTB based on LPS injections exist, but with a low survival rate. There is a lack of information regarding clinically used pharmacological substances to induce PTB and their consequences on brain development. Mifepristone (RU-486) is a drug used clinically to induce preterm labor. This study aims to elaborate and characterize a new model of induced-PTB and PWMIs by the gestational injection of RU-486 and the perinatal injection of pups with IL-1beta. A RU-486 single subcutaneous (s.c.) injection at embryonic day (E)18.5 induced PTB at E19.5 in pregnant OF1 mice. All pups were born alive and were adopted directly after birth. IL-1beta was injected intraperitoneally from postnatal day (P)1 to P5. Animals exposed to both RU-486 and IL-1beta demonstrated microglial reactivity and subsequent PWMIs. In conclusion, the s.c. administration of RU-486 induced labor within 24 h with a high survival rate for pups. In the context of perinatal inflammation, RU-486 labor induction significantly decreases microglial reactivity in vivo but did not prevent subsequent PWMIs. [ABSTRACT FROM AUTHOR]

This paper reports on the experimental and numerical results of the hythane diffusion flame enriched by oxygen, realized in a coaxial burner characterized by a central jet of hythane injection with an internal diameter of d fuel = 6 mm and an annular jet of oxidant injection with a diameter of d ox = 18 mm. For velocity measurements, the Particle Image Velocimetry (PIV) technology is used. The numerical study is based on the K-ω-SST Turbulent Model and the Eddy Dissipation Model (EDM) for combustion. Firstly, a comparative study is carried out between experimental and numerical simulation of the flow dynamics in the hythane/Air + O 2 flame. Secondly, the numerical results show that the oxygen enrichment increases the temperature of the hythane flame and minimizes the formation of harmful gases into the environment. • Oxygen enrichment favors the flame temperature and reduces the hythane flame length. • The oxygen enrichment reduces the total volume of combustion products. • The oxygen enrichment minimizes the carbon monoxide production. • The mixture fraction characterizes the mixture quality between reactants. [ABSTRACT FROM AUTHOR]

Addressing sustainable energy storage remains crucial for transitioning to renewable sources. While Li‐ion batteries have made significant contributions, enhancing their capacity through alternative materials remains a key challenge. Micro‐sized silicon is a promising anode material due to its tenfold higher theoretical capacity compared to conventional graphite. However, its substantial volumetric expansion during cycling impedes practical application due to mechanical failure and rapid capacity fading. A novel approach is proposed to mitigate this issue by incorporating trace amounts of aluminum into the micro‐sized silicon electrode using ball milling. Density functional theory (DFT) is employed to establish a theoretical framework elucidating how grain boundary sliding, a key mechanism involved in preventing mechanical failure is facilitated by the presence of trace aluminum at grain boundaries. This, in turn, reduces stress accumulation within the material, reducing the likelihood of failure. To validate the theoretical predictions, capacity retention experiments are conducted on undoped and Al‐doped micro‐sized silicon samples. The results demonstrate significantly reduced capacity fading in the doped sample, corroborating the theoretical framework and showcasing the potential of aluminum doping for improved Li‐ion battery performance. [ABSTRACT FROM AUTHOR]

Purpose: Surgical treatment of three or four part fractures of the proximal humerus is complex. Different conservative techniques have been described. The main goal of this study was to compare the clinical and radiological outcomes of Bilboquet and locking plate at two year follow-up.Methods: This is a retrospective, comparative study, with a continuous series of 41 patients. Bony fixation was achieved with a Bilboquet device in 22 patients or a locking plate in 19 patients. Patient evaluation included clinical data: shoulder range of motion, Constant-Murley shoulder score and DASH (Disabilities of the Arm, Shoulder and Hand) score, and imaging using standard shoulder X-rays.Results: Of the 41 patients included, 1 patient was lost to follow-up in the locking plate group. At a mean follow-up of 24 months patients in Bilboquet group showed a Constant score higher than in locking plate (p = 0.02). Range of motion and DASH score were not significantly different between the two groups. avascular necrosis occured in three patients of Bilboquet group (14%) versus in two patients in the locking plate group (11%) (p > 0.5). Complication and reintervention rate were non-significantly higher in the locking plate group than in the Bilboquet group (37 vs 14%).Conclusion: Bilboquet and locking plate give good functional outcomes in complex proximal humerus fractures. However, the Bilboquet device appears to provide better functional results than locking plate at mid-term follow-up. [ABSTRACT FROM AUTHOR]

CO2 electroreduction (CO2R) operating in acidic media circumvents the problems of carbonate formation and CO2 crossover in neutral/alkaline electrolyzers. Alkali cations have been universally recognized as indispensable components for acidic CO2R, while they cause the inevitable issue of salt precipitation. It is therefore desirable to realize alkali‐cation‐free CO2R in pure acid. However, without alkali cations, stabilizing *CO2 intermediates by catalyst itself at the acidic interface poses as a challenge. Herein, we first demonstrate that a carbon nanotube‐supported molecularly dispersed cobalt phthalocyanine (CoPc@CNT) catalyst provides the Co single‐atom active site with energetically localized d states to strengthen the adsorbate‐surface interactions, which stabilizes *CO2 intermediates at the acidic interface (pH=1). As a result, we realize CO2 conversion to CO in pure acid with a faradaic efficiency of 60 % at pH=2 in flow cell. Furthermore, CO2 is successfully converted in cation exchanged membrane‐based electrode assembly with a faradaic efficiency of 73 %. For CoPc@CNT, acidic conditions also promote the intrinsic activity of CO2R compared to alkaline conditions, since the potential‐limiting step, *CO2 to *COOH, is pH‐dependent. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts and devices for acidic CO2R. [ABSTRACT FROM AUTHOR]

CO2 electroreduction (CO2R) operating in acidic media circumvents the problems of carbonate formation and CO2 crossover in neutral/alkaline electrolyzers. Alkali cations have been universally recognized as indispensable components for acidic CO2R, while they cause the inevitable issue of salt precipitation. It is therefore desirable to realize alkali‐cation‐free CO2R in pure acid. However, without alkali cations, stabilizing *CO2 intermediates by catalyst itself at the acidic interface poses as a challenge. Herein, we first demonstrate that a carbon nanotube‐supported molecularly dispersed cobalt phthalocyanine (CoPc@CNT) catalyst provides the Co single‐atom active site with energetically localized d states to strengthen the adsorbate‐surface interactions, which stabilizes *CO2 intermediates at the acidic interface (pH=1). As a result, we realize CO2 conversion to CO in pure acid with a faradaic efficiency of 60 % at pH=2 in flow cell. Furthermore, CO2 is successfully converted in cation exchanged membrane‐based electrode assembly with a faradaic efficiency of 73 %. For CoPc@CNT, acidic conditions also promote the intrinsic activity of CO2R compared to alkaline conditions, since the potential‐limiting step, *CO2 to *COOH, is pH‐dependent. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts and devices for acidic CO2R. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT-based adsorption energies for C, CH x and COH on various transition metal sites. • The slopes of the scaling lines can be predicted based on electron-counting rules. • Anomalous structure dependence for the offsets of CH vs C and COH vs C. • COH hydrogenation to produce C is energy-intensive during CO 2 reduction to CH 4. The arduous modelling of reactions at heterogeneous catalysts is greatly simplified when adsorption-energy scaling relations between intermediates exist. Generally, the offset of these linear relations is structure-independent when the slope is unity and otherwise depends on the coordination number of the active sites. Here we examine the adsorption of *C, *CH, *CH 2 , *CH 3 and *COH on five different surface sites of nine transition metals to establish their structure-sensitive scaling relations. Interestingly, we show that the scaling relations of *C (valency 4) and C-containing species with valency 3 (*CH, *COH) have peculiar structure-independent offsets. These offsets stem from the analogous bonding of those species to the adsorption sites, in spite of their dissimilar valency. We show how this result implies that reaction pathways in catalysis involving *C, *CH and *COH, for instance CO 2 electroreduction to CH 4 , will usually have sizable thermodynamic limits imposed to their optimization. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have become a prominent theme in heterogeneous catalysis, not least because of the potential fundamental insight into active sites. The desired level of understanding, however, is prohibited due to the inhomogeneity of most supported SACs and the lack of suitable tools for structure–activity correlation studies with atomic resolution. Herein, we describe the potency of electrospray ionization mass spectrometry (ESI‐MS) to study molecularly defined SACs supported on polyoxometalates in catalytic reactions. We identified the exact composition of active sites and their evolution in the catalytic cycle during CO and alcohol oxidation reactions performed in the liquid phase. Critical information on metal‐dependent reaction mechanisms, the key intermediates, the dynamics of active sites and even the stepwise activation barriers were obtained, which would be challenging to gather via prevailingly adopted techniques in SAC research. DFT calculations revealed intricate details of the reaction mechanisms, and strong synergies between ESI‐MS defined SAC sites and electronic structure theory calculations become apparent. [ABSTRACT FROM AUTHOR]