328 research outputs found
Photoabsorption in carbon monoxide: Stieltjes–Tchebycheff calculations in the separated-channel static-exchange approximation
Theoretical investigations of total and partial-channel photoabsorption cross sections in carbon monoxide are reported employing the Stieltjes–Tchebycheff (S–T) technique and separated-channel static-exchange calculations. Pseudospectra of discrete transition frequencies and oscillator strengths appropriate for individual excitations of each of the six occupied molecular orbitals are constructed using Hartree–Fock core functions and normalizable Gaussian orbitals to describe the photoexcited and ejected electrons. Use of relatively large basis sets of compact and diffuse functions insures the presence of appropriate discrete Rydberg states in the calculations and provides sufficiently dense pseudospectra for the determination of convergent photoionization cross sections from the S–T technique. The calculated discrete vertical electronic excitation spectra are in very good agreement with measured band positions and intensities, and the partial-channel photoionization cross sections are in correspondingly good accord with recent electron–electron (e,2e) coincidence, synchrotron-radiation, and line-source branching-ratio measurements. Predicted resonance features in the X, B, O2s−1, and carbon K-shell channels are in particularly good agreement with the positions and intensities in the measured cross sections. A modest discrepancy between experiment and theory in the A-channel cross section is tentatively attributed to channel-coupling mechanisms associated with opening of the 1pi shell. The total vertical electronic S–T photoionization cross section for parent-ion production is in excellent agreement with recent electron–ion coincidence measurements. Comparisons are made between ionization processes in carbon monoxide and in the previously studied nitrogen molecule, and similarities and differences in the respective cross sections are clarified in terms of conventional molecular-orbital theory
Photoexcitation and ionization in ozone: Stieltjes–Tchebycheff studies in the separated-channel static-exchange approximation
Theoretical studies are reported of total and partial-channel photoexcitation/ionization cross sections in ozone employing Stieltjes–Tchebycheff (S–T) techniques and the separated-channel static-exchange approximation. As in previously reported investigations of excitation and ionization spectra in diatomic and polyatomic molecules employing this approach, vertical electronic dipole transition spectra for the twelve occupied canonical Hartree–Fock symmetry orbitals in ozone are constructed using large Gaussian basis sets, appropriate computational methods, and noncentral static-exchange potentials of correct molecular symmetry. Experimental rather than Koopmans ionization potentials are employed when available in construction of transition energies to avoid the incorrect ionic-state orderings predicted by Hartree–Fock theory, and to insure that the calculated series have the appropriate limits. The spectral characteristics of the resulting improved-virtual-orbital discrete excitation series and corresponding static-exchange photoionization continua are interpreted in terms of contributions from valencelike 7a1(sigma*), 2b1(pix*), and 5b2(sigma*) virtual orbitals, and appropriate diffuse Rydberg functions. The 2b1(pix*) valence orbital apparently contributes primarily to discrete or autoionizing spectra, whereas the 7a1(sigma*) and 5b2(sigma*) orbitals generally appear in the various photoionization continua. Moreover, there is also evidence of strong 2p-->kd atomiclike contributions to ka2 final-state channels in the photoionization continua. The calculated outer-valence-shell 6a1, 4b2, and 1a2 excitation series are compared with electron impact–excitation spectra in the 9 to 13 eV interval, and the corresponding partial-channel photoionization cross sections are contrasted and compared with the results of previously reported studies of photoionization in molecular oxygen. The intermediate- and inner-valence-shell excitation series and corresponding photoionization cross sections are in general accord with quantum-defect estimates and with the measured electron-impact spectra, which are generally unstructured above ~22 eV. Of particular interest in the intermediate-valence-shell spectra is the appearance of a strong sigma-->sigma* feature just above threshold in the 3b2-->kb2 photoionization cross section, in qualitative agreement with previously reported studies of the closely related 3sigmag-->ksigmau cross section in molecular oxygen. Finally, qualitative comparisons are made of the calculated K-edge excitation and ionization spectra in ozone with recently reported photoabsorption studies in molecular oxygen
Photoexcitation and ionization in carbon dioxide: Theoretical studies in the separated-channel static-exchange approximation
Theoretical studies are reported of total and partial-channel photoexcitation and ionization cross sections in carbon dioxide. As in previously reported studies of discrete and continuum dipole spectra in diatomic (N2, CO, O2, F2) and polyatomic (H2O, H2CO, O3) molecules in this series, separated-channel static-exchange calculations of vertical-electronic transition energies and oscillator strengths and Stieltjes-Tchebycheff moment methods are employed in the development. Detailed comparisons are made of the static-exchange excitation and ionization spectra with photoabsorption, electron-impact excitation, and quantum-defect estimates of discrete transition energies and intensities, and with partial-channel photoionization cross sections obtained from fluorescence measurements and from tunable-source and (e,2e) photoelectron spectroscopy. The spectral characteristics of the various discrete series and continua are interpreted in terms of contributions from compact 2πu(π*), 5σg(σ*), and 4σu(σ*) virtual valence orbitals, and from more diffuse discrete and continuum Rydberg orbitals. The 2πu(π*) orbital is found to contribute to discrete excitation series, whereas the 5σg (σ*) and 4σu (σ*) orbitals generally appear in the photoionization continua as resonance-like diabatic valence features. Good agreement obtains between the calculated discrete excitation series and the results of a recent analysis of the available spectroscopic data. The calculated outer-valence-shell (1πg-1)X 2Πg, (1πu-1)A 2Πu, (3σu-1)B 2Σu+, and (4σg-1)C 2Σg+ partial-channel photoionization cross sections are in good accord with measured values, and clarify completely the origins of the various structures in the observed spectra. There is evidence, however, of coupling among scattering states associated with 1πg-1 and 1πu-1 ionic channels, giving rise to moderate disagreement with tunable-source photoelectron and fluorescence measurements over a portion of the spectrum. In the inner-valence-shell region, the calculated 2σu-1 and 3σg-1 cross sections are in qualitative accord with the observed many-electron spectral intensities, and provide a basis for quantitative interpretation when combined with appropriate intensity-borrowing calculations. The calculated carbon and oxygen K-edge cross sections are in good agreement with available cross sections obtained from electron-impact and photoabsorption measurements. It is of particular interest to find the oxygen K-edge (1σg-1, 1σu-1) cross section exhibits both the expected 5σg(σ*) and 4σu(σ*) resonance-like features. Finally, comparisons are made throughout of the discrete and continuum spectra in carbon dioxide with the results of previously reported studies in CO and O2, and the origins of the similarities and differences in the cross sections in these cases are clarified
Prevalence and Prognostic Influence of Peripheral Arterial Disease in Patients ≥40 Years Old Admitted into Hospital Following an Acute Coronary Event
AbstractObjectiveA significant proportion of patients with ischemic heart disease have associated peripheral arterial disease (PAD), but many are asymptomatic and this condition remains underdiagnosed. We aimed to study the prevalence of PAD in patients with an acute coronary syndrome (ACS) and to evaluate its influence in hospital clinical outcomes.MethodsThe PAMISCA register is a prospective, multicenter study involving patients ≥40 years old with ACS admitted to selected Spanish hospitals. All patients had their ankle-brachial index (ABI) measured between days 3 and 7 after the ischemic event.Results1410 ACS patients (71.4% male) were included. PAD determined by ABI was documented in 561 patients (39.8%). Factors independently related to PAD were age (OR: 1.04; 95% CI: 1.03–1.06; p<0.001), smoking (OR: 1.88; 95% CI: 1.41–2.49; p<0.0001), diabetes (OR: 1.30; 95% CI: 1.02–1.65; p<0.05), previous cardiac disease (OR: 1.54; 95% CI: 1.22–1.95; p<0.001) and previous cerebrovascular disease (OR: 1.90; 95% CI: 1.28–2.80; p<0.001). Following the ACS, an ABI≤0.90 was associated with increased cardiovascular mortality (OR: 5.45; 95% CI: 1.16–25.59; p<0.05) and a higher risk of cardiovascular complications.ConclusionThe prevalence of PAD in patients ≥40 years presenting with ACS is high and it is associated with increased cardiovascular risk
Image-Based, Fiber Guiding Scaffolds: A Platform for Regenerating Tissue Interfaces
In the oral and craniofacial complex, tooth loss is the most commonly acquired disfiguring injury. Among the most formidable challenges of reconstructing tooth-supporting osseous defects in the oral cavity is the regeneration of functional multi-tissue complexes involving bone, ligament, and tooth cementum. Furthermore, periodontal multi-tissue engineering with spatiotemporal orientation of the periodontal ligament (PDL) remains the most challenging obstacle for restoration of physiological loading and homeostasis. We report on the ability of a hybrid computer-designed scaffold?developed utilizing computed tomography?to predictably facilitate the regeneration and integration of dental supporting tissues. Here, we provide the protocol for rapid prototyping, manufacture, surgical implantation, and evaluation of dual-architecture scaffolds for controlling fiber orientation and facilitating morphogenesis of bone-ligament complexes. In contrast to conventional single-system methods of fibrous tissue formation, our protocol supports rigorous control of multi-compartmental scaffold architecture using computational scaffold design and manufacturing by 3D printing, as well as the evaluation of newly regenerated tissue physiology for clinical implementation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140247/1/ten.tec.2013.0619.pd
Zirconium Metal-Organic Polyhedra with Dual Behavior for Organophosphate Poisoning Treatment
Organophosphate nerve agents and pesticides are extremely toxic compounds because they result in acetylcholinesterase (AChE) inhibition and concomitant nerve system damage. Herein, we report the synthesis, structural characterization, and proof-of-concept utility of zirconium metal-organic polyhedra (Zr-MOPs) for organophosphate poisoning treatment. The results show the formation of robust tetrahedral cages [((n-butylCpZr)3(OH)3O)4L6]Cl6(Zr-MOP-1; L = benzene-1,4-dicarboxylate, n-butylCp = n-butylcyclopentadienyl, Zr-MOP-10, and L = 4,4′-biphenyldicarboxylate) decorated with lipophilic alkyl residues and possessing accessible cavities of ∼9.8 and ∼10.7 Å inner diameters, respectively. These systems are able to both capture the organophosphate model compound diisopropylfluorophosphate (DIFP) and host and release the AChE reactivator drug pralidoxime (2-PAM). The resulting 2-PAM@Zr-MOP-1(0) host-guest assemblies feature a sustained delivery of 2-PAM under simulated biological conditions, with a concomitant reactivation of DIFP-inhibited AChE. Finally, 2-PAM@Zr-MOP systems have been incorporated into biocompatible phosphatidylcholine liposomes with the resulting assemblies being non-neurotoxic, as proven using neuroblastoma cell viability assays
Australian Sphingidae – DNA Barcodes Challenge Current Species Boundaries and Distributions
© 2014 Rougerie et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
Photoexcitation and ionization in ozone: Stieltjes–Tchebycheff studies in the separated‐channel static‐exchange approximation
Correlación en triatlón masculino entre fases y resultado inal en los JJOO de Pekin 2008
Introduction: Triathlon is a sport that is composed of the combination of three phases of competition. The most widespread triathlon is the Olympic, and is used in the Olympic Games, consists of swim, 1.5 km, bike 40 km and run 10 km. Aims: To determine the influence of the duration and order of the phases with the final result of the test in the male triathlon in the Olympic Games Beijing 2008. Method: We analyzed the data of 50 athletes who finished. Results and conclusions: The final result is not determined by the order of the phases, nor by the duration of these, the least influential phase has been Bike with rs = .039; p = .351; Being the one that has occupied the most time with 52.55%; The most influential phase was the Run phase with rs = .991; and p = .000; and R2 = .982 and with duration 30.21%.Introducción: El triatlón es un deporte que se compone de la combinación de tres fases de competición. La modalidad de triatlón más extendida es la olímpica, y es utilizada en los Juegos Olímpicos (JJOO), se compone de nado 1,5 km, bicicleta 40 km y carrera 10 km. Objetivos: Determinar la influencia de la duración y orden de las fases con el resultado final de la prueba en el triatlón masculino en los JJOO Pekín 2008. Método: Se analizaron los datos de 50 deportistas que finalizaron. Resultados y conclusiones: El resultado final no viene determinado ni por el orden de las fases, ni por la duración de estas, la fase menos influyente ha sido Bike con rs= 0,039; p =0,351; siendo la que más tiempo ha ocupado con un 52,55%; la fase más influyente ha sido la fase Run con rs=0,991; y p=0,000; y R2=0,982 y con duración 30,21%
Increased Expression of Musashi-1 Evidences Mesenchymal Repair in Maxillary Sinus Floor Elevation
This study aimed to analyze the expression of Musashi-1 (MSI1) in maxillary native bone and grafted
bone after maxillary sinus floor elevation. To do so, fifty-seven bone biopsies from 45 participants were
studied. Eighteen samples were collected from native bone while 39 were obtained 6 months after
maxillary sinus grafting procedures. Musashi-1 was analyzed by immunohistochemistry and RT-PCR.
MSI1 was detected in osteoblasts and osteocytes in 97.4% (38/39) of grafted areas. In native bone,
MSI1 was detected in only 66.6% (12/18) of the biopsies, mainly in osteocytes. Detection of MSI1 was
significantly higher in osteoprogenitor mesenchymal cells of grafted biopsies (p < 0.001) but minor in
smooth muscle and endothelial cells; no expression was detected in adipocytes. The mesenchymal cells
of the non-mineralized tissue of native bone showed very low nuclear expression of MSI1, in comparison
to fusiform cells in grafted areas (0.28(0.13) vs. 2.10(0.14), respectively; p < 0.001). Additionally, the
detection of MSI1 mRNA was significantly higher in biopsies from grafted areas than those from native
bone (1.00(0.51) vs. 60.34(35.2), respectively; p = 0.029). Thus, our results regardig the significantly
higher detection of Musashi-1 in grafted sites than in native bone reflects its importance in the
remodeling/repair events that occur after maxillary sinus floor elevation in humans.This investigation was partially supported by Research Groups #CTS-138
and #CTS-1028 (Junta de Andalucía, Spain). MPM was supported by the Andalucía Talent Hub Program from
the Andalusian Knowledge Agency (co-funded by the European Union’s Seventh Framework Program, Marie
Skłodowska-Curie actions (COFUND – Grant Agreement n° 291780) and the Ministry of Economy, Innovation,
Science and Employment of the Junta de Andalucía)
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