Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

Within the “Compartmentalised Smart Factory” approach of the ONE-FLOW project the implementation of different catalysts in “compartments” provided by Pickering emulsions and their application in continuous flow is targeted. We present here the development of heterogeneous Pd-catalysts that are ready to be used in combination with biocatalysts for catalytic cascade syntheses of active pharmaceutical ingredients (APIs). In particular, we focus on the application of the catalytic systems for Suzuki-Miyaura cross coupling reactions, which is the key step in the syntheses of the targeted APIs valsartan and sacubitril. An immobilised enzyme will accomplish the final product formation via hydrolysis. In order to create large interfacial area for the catalytic reactions and to keep the reagents separated until required, the catalyst particles are used to stabilise Pickering emulsions of oil and water. A set of Ce-Sn-Pd-oxides with the molecular formula Ce0.99-xSnxPd0.01O2-(x= 0-0.99) has been prepared utilising a simple single-step solution combustion method. The high applicability of the catalysts for different functional groups and their minimal leaching behaviour is demonstrated with various Suzuki-Miyaura cross coupling reactions in batch as well as in continuous flow employing the so-called “Plug & Play reactor”. Finally, we demonstrate the use of these particles as the sole emulsifier of oil + water emulsions for a range of oils

Chiral Perturbation Approach to the pp -> pp pi0 Reaction Near Threshold

The usual theoretical treatments of the near-threshold $pp \rightarrow pp\pi^0$ reaction are based on various phenomenological Lagrangians. In this work we examine the relationship between these approaches and a systematic chiral perturbation method. Our chiral perturbation calculation indicates that the pion rescattering term should be significantly enhanced as compared with the traditional phenomenological treatment, and that this term should have substantial energy and momentum dependence. An important consequence of this energy-momentum dependence is that, for a representative threshold kinematics and within the framework of our semiquantitative calculation, the rescattering term interferes destructively with the Born-term in sharp contrast to the constructive interference obtained in the conventional treatment. This destructive interference makes theoretical cross sections for $pp \rightarrow pp\pi^0$ much smaller than the experimental values, a feature that suggests the importance of the heavy-meson exchange contributions to explain the experimental data.Comment: 35 pages (REVTeX), 5 figures as 1 PostScript file acknowledgement changed, reference added, Phys.Rev.C (in print

Alignments of Voids in the Cosmic Web

We investigate the shapes and mutual alignment of voids in the large scale matter distribution of a LCDM cosmology simulation. The voids are identified using the novel WVF void finder technique. The identified voids are quite nonspherical and slightly prolate, with axis ratios in the order of c:b:a approx. 0.5:0.7:1. Their orientations are strongly correlated with significant alignments spanning scales >30 Mpc/h. We also find an intimate link between the cosmic tidal field and the void orientations. Over a very wide range of scales we find a coherent and strong alignment of the voids with the tidal field computed from the smoothed density distribution. This orientation-tide alignment remains significant on scales exceeding twice the typical void size, which shows that the long range external field is responsible for the alignment of the voids. This confirms the view that the large scale tidal force field is the main agent for the large scale spatial organization of the Cosmic Web.Comment: 10 pages, 4 figures, submitted to MNRAS, for high resolution version, see http://www.astro.rug.nl/~weygaert/tim1publication/voidshape.pd

Muon capture by a proton in heavy baryon chiral perturbation theory

The matrix element for muon capture by a proton is calculated to O(p^3) within heavy baryon chiral perturbation theory using the new O(p^3) Lagrangian of Ecker and Mojzis. External nucleon fields are renormalized using the appropriate definition of the wave function renormalization factor Z_N. Our expression for Z_N differs somewhat from that found in existing literature, but is the one which is consistent with the Lagrangian we use and the one which ensures, within our approach, the nonrenormalization of the vector coupling as required by the conserved vector current. Expressions for the standard muon capture form factors are derived and compared to experimental data and we determine three of the coefficients of the Ecker - Mojzis Lagrangian, namely, b_7, b_{19}, and b_{23}.Comment: 14 pages, LaTeX, using revte

Analysis of the tonic vibration reflex: influence of vibration variables on motor unit synchronization and fatigue

The influence of vibration frequency (40, 80, 100, 120, 150, or 200 Hz) at selected displacement amplitudes (0.2, 0.3 mm) on tonic vibration reflex (TVR) characteristics was investigated. The degree of synchronization of motor unit activity with vibratory stimuli in ten humans was determined using the electromyographic (EMG) activity of the finger and wrist flexor muscles when vibration was applied to the distal tendons of the hand flexor muscles. The EMG spectral analysis indicates that harmonic and subharmonic motor unit synchronization mechanisms contribute to the modulation of the amplitude of the TVR as the vibration frequency increases. Harmonic synchronization decreases while subharmonic synchronization increases as vibration frequency increases. It is suggested that the synchronization process influences muscle fatigue, since it forces the driving of motor units, leading to a decrease in contraction efficiency. This phenomenon most probably results from an impairment of excitation-contraction coupling. High-frequency vibration (>150 Hz) tends to induce less motor unit synchronization in a frequency range beyond the known mechanical resonance of biological tissues. The findings of this study may be applied to the design of hand-held power tools, since their vibration triggers the TVR in active muscles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42240/1/421-75-6-504_70750504.pd

Chiral Perturbation Theory and the pp -> pp pi0 Reaction Near Threshold

A chiral-perturbative consideration of the near-threshold pp -> pp pi0 reaction indicates that the pion-rescattering term has a substantial energy and momentum dependence. The existing calculations that incorporate this dependence give pion rescattering contributions significantly larger than those of the conventional treatment, and this enhanced rescattering term interferes destructively with the one-body impulse term, leading to theoretical cross sections that are much smaller than the observed values. However, since the existing calculations are based on coordinate-space representation, they involve a number of simplifying assumptions about the energy-momentum flow in the rescattering diagram, even though the delicate interplay between the one-body and two-body terms makes it desirable to avoid these kinematical assumptions. We carry out here a momentum-space calculation that retains the energy-momentum dependence of the vertices as predicted by chiral perturbation theory. Our improved treatment increases the rescattering amplitude by a factor of 3 over the value obtained in the r-space calculations. The pp -> pp pi0 transition amplitude, which is now dominated by the rescattering term, leads to the cross section much larger than what was reported in the approximate r-space calculations. Thus, the extremely small cross sections obtained in the previous chiral perturbative treatments of this reaction should be considered as an accidental consequence of the approximations employed rather than a general feature.Comment: 25 pages,REVTEX, 5 ps figure

Towards a field theoretic understanding of NN->NNpi

We study the production amplitude for the reaction NN->NNpi up to next--to--leading order in chiral perturbation theory using a counting scheme that takes into account the large scale introduced by the initial momentum. In particular we investigate a subtlety that arises once the leading loop contributions are convoluted with the NN wavefunctions as demanded by the non--perturbative nature of the NN interaction. We show how to properly identify the irreducible contribution of loop diagrams in such type of reaction. The net effect of the inclusion of all next-to-leading order loops is to enhance the leading rescattering amplitude by a factor of 4/3, bringing its contribution to the cross section for pp->dpi+ close to the experimental value.Comment: 15 Pages, 5 Figure

Chiral perturbation theory calculation for pn -> dpipi at threshold

We investigate the reaction pn -> dpipi in the framework of Chiral Perturbation Theory. For the first time a complete calculation of the leading order contributions is presented. We identify various diagrams that are of equal importance as compared to those recognized in earlier works. The diagrams at leading order behave as expected by the power counting. Also for the first time the nucleon-nucleon interaction in the initial, intermediate and final state is included consistently and found to be very important. This study provides a theoretical basis for a controlled evaluation of the non-resonant contributions in two-pion production reactions in nucleon-nucleon collisions.Comment: 24 pages, 3 figures, 3 table

Current Dyspnea Among Long-Term Survivors of Early-Stage Non-small Cell Lung Cancer

IntroductionDyspnea is common among lung cancer patients. As most studies of dyspnea have reviewed patients with active cancer or immediately after treatment, its prevalence during the longer-term period once treatment has been completed is not well characterized. This study quantifies the prevalence of dyspnea among lung cancer survivors and identifies potential correlates that may be amenable to intervention.MethodsCross-sectional survey of 342 patients with disease-free, stage I, non-small cell lung cancer, assessed 1 to 6 years after surgical resection. Dyspnea was quantified using the Baseline Dyspnea Index. Any moderate/strenuous physical activity was measured using the Godin Leisure-Time Exercise Questionnaire. Mood disorder symptoms were assessed using the Hospital Anxiety and Depression Scale. Multiple regression analyses were used to examine demographic, medical, and health-related correlates of dyspnea.ResultsMean age was 68.9 years. Average predicted preoperative forced expiratory volume in 1 second was 89.0%. Current dyspnea, defined by a Baseline Dyspnea Index score of 9 or less, existed among 205 (60%) individuals. For 133 (65%) of these patients, dyspnea was absent preoperatively. Multivariate correlates of current dyspnea included preoperative dyspnea (odds ratio [OR] = 5.31), preoperative diffusing capacity (OR = 0.98), lack of moderate/strenuous physical activity (OR = 0.41), and the presence of clinically significant depression symptoms (OR = 4.10).ConclusionsDyspnea is common 1 to 6 years after lung cancer resection, and is associated with the presence of preoperative dyspnea, reduced diffusing capacity, clinically significant depression symptoms, and lack of physical activity. Further research is needed to test whether strategies that identify and treat patients with these conditions attenuate dyspnea among lung cancer survivors

Alpha, Betti and the Megaparsec Universe: on the Topology of the Cosmic Web

We study the topology of the Megaparsec Cosmic Web in terms of the scale-dependent Betti numbers, which formalize the topological information content of the cosmic mass distribution. While the Betti numbers do not fully quantify topology, they extend the information beyond conventional cosmological studies of topology in terms of genus and Euler characteristic. The richer information content of Betti numbers goes along the availability of fast algorithms to compute them. For continuous density fields, we determine the scale-dependence of Betti numbers by invoking the cosmologically familiar filtration of sublevel or superlevel sets defined by density thresholds. For the discrete galaxy distribution, however, the analysis is based on the alpha shapes of the particles. These simplicial complexes constitute an ordered sequence of nested subsets of the Delaunay tessellation, a filtration defined by the scale parameter, $\alpha$. As they are homotopy equivalent to the sublevel sets of the distance field, they are an excellent tool for assessing the topological structure of a discrete point distribution. In order to develop an intuitive understanding for the behavior of Betti numbers as a function of $\alpha$, and their relation to the morphological patterns in the Cosmic Web, we first study them within the context of simple heuristic Voronoi clustering models. Subsequently, we address the topology of structures emerging in the standard LCDM scenario and in cosmological scenarios with alternative dark energy content. The evolution and scale-dependence of the Betti numbers is shown to reflect the hierarchical evolution of the Cosmic Web and yields a promising measure of cosmological parameters. We also discuss the expected Betti numbers as a function of the density threshold for superlevel sets of a Gaussian random field.Comment: 42 pages, 14 figure