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Photoinduced phase transitions in correlated materials promise diverse applications from ultrafast switches to optoelectronics. Resolving those transitions and possible metastable phases temporally are key enablers for these applications, but challenge existing experimental approaches. Extreme nonlinear optics can help probe phase changes, as higher-order nonlinearities have higher sensitivity and temporal resolution to band structure and lattice deformations. Here the ultrafast transition from the semiconducting to the metallic phases in polycrystalline thin-film NbO_{2} is investigated by time-resolved harmonic spectroscopy. The emission strength of all harmonic orders shows a steplike suppression when the excitation fluence exceeds a threshold (â¼11-12 mJ/cm^{2}), below the fluence required for the thermal transition-a signature of the nonthermal emergence of a metallic phase within 100±20 fs. This observation is backed by full ab initio simulations as well as a 1D chain model of high-harmonic generation from both phases. Our results demonstrate femtosecond harmonic probing of phase transitions and nonthermal dynamics in solids.
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We present a table-top extreme ultraviolet (XUV) beamline for measuring time- and frequency-resolved XUV-excited optical luminescence (XEOL) with additional femtosecond-resolution XUV transient absorption spectroscopy functionality. XUV pulses are generated via high-harmonic generation using a near-infrared pulse in a noble gas medium and focused to excite luminescence from a solid sample. The luminescence is collimated and guided into a streak camera where its spectral components are temporally resolved with picosecond temporal resolution. We time-resolve XUV-excited luminescence and compare the results to luminescence decays excited at longer wavelengths for three different materials: (i) sodium salicylate, an often used XUV scintillator; (ii) fluorescent labeling molecule 4-carbazole benzoic (CB) acid; and (iii) a zirconium metal oxo-cluster labeled with CB, which is a photoresist candidate for extreme-ultraviolet lithography. Our results establish time-resolved XEOL as a new technique to measure transient XUV-driven phenomena in solid-state samples and identify decay mechanisms of molecules following XUV and soft-x-ray excitation.
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An evaluation of possible interactions with enzymes of drug metabolism (cytochromes P450, CYP) is an important part of studies on safety and, in general, on the properties of any drug or biologically active compound. The article is focused on the preliminary metabolic study of selected 2,6,9-trisubstituted purine kinase inhibitors with significant anticancer activities which we have developed. The compounds BP-21 and BP-117 represent strong CDK inhibitors and the compound BPA-302 was developed as selective FLT3-ITD kinase inhibitor. Here, emphasis is placed on interactions of these compounds with the nine most important forms of CYP to evaluate the possibility of inhibition of these enzymes. The possibility of their inhibitory effect was studied in vitro on selected human liver microsomal CYP enzymes. The most affected enzyme was CYP2C19. Its activity dropped to 22 % of its original value by BPA 302, to 13 % by BP-21 and to 6 % by BP-117 at the highest concentration tested (250 µmol·l(-1)). The results suggest that the metabolism of concomitantly administered drugs should not be significantly affected at lower doses. Molecular docking of BPA-302 indicated that it can bind to active site of both CYP2C19 and CYP2D6 enzymes above the heme cofactor corroborating the experimental data.
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Inibidores das Enzimas do Citocromo P-450/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Microssomos Hepáticos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Purinas/farmacologia , Inibidores das Enzimas do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/química , Interações Medicamentosas , Humanos , Isoenzimas , Cinética , Microssomos Hepáticos/enzimologia , Simulação de Acoplamento Molecular , Conformação Proteica , Inibidores de Proteínas Quinases/química , Purinas/química , Relação Estrutura-AtividadeRESUMO
The rotational constants of s-trans and s-cis methyl methacrylate and methacrylic acid are determined from microwave spectra. All singly substituted heavy-atom isotopologs of the four species are measured in natural abundance. The experimental rotational constants are combined with anharmonic vibrational corrections using the Coulomb-attenuating method, Becke, three-parameter, Lee-Yang-Parr density functional with Grimme's D3 dispersion corrections and the Becke-Johnson damping function, yielding precise semi-experimental equilibrium rotational constants. These constants are used to determine semi-experimental equilibrium structures with sub-picometer accuracy, suitable for benchmarking purposes.
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The microwave spectra of 10 teflic acid isotopologues were recorded in the frequency range of 3-25 GHz using supersonic jet-expansion Fourier transform microwave spectroscopy. Despite being asymmetric in its equilibrium structure, the delocalization of the hydrogen atom leads to a symmetric top vibrational ground state structure. In this work, we present the zero point structure obtained from the experimental rotational constants and an approach to determine the semi-experimental equilibrium structure aided by ab initio data. The Te-O bond length determined in the equilibrium structure is accurate to the picometer and can be used as a benchmark for computational methods treating relativistic effects.
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In this work, we compare the results obtained with 89 computational methods for predicting noncovalent bond lengths in weakly bound complexes. Evaluations for the performance in noncovalent interaction energies and covalent bond lengths obtained from five other data sets are included. The overall best performing density functional is the ωB97M-V method, achieving balanced results across all three categories. For noncovalent geometries, the best methods include B97M-V, B3LYP-D3(BJ) and DSD-PBEPBE-D3(BJ). The effects of systematic improvement of the density functional approximation and of dispersion corrections are also discussed.
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Accurate data sets including noncovalent interactions have become essential for benchmarking computational methods. However, while there is much focus on obtaining an accurate description of relative energies, reliable prediction of accurate equilibrium geometries is also important. To facilitate the benchmarking of computed geometries, the current work includes an accurate data set of semiexperimental equilibrium geometries of noncovalent complexes that can be directly compared to ab initio data. The structures are based on high-accuracy spectroscopic data, combined with vibrational corrections at the double-hybrid density functional level. The current work is designed to complement available data sets of semiexperimental geometries of small rigid molecules and ab initio geometries of complexes. The benchmark-quality data comprises 16 complexes and includes dispersion interactions, hydrogen bonding, CH/π···π interactions, and trimers. In addition to the reference data, accurate counterpoise-corrected geometries have been obtained up to the CCSD level, along with interaction energies. A short overview of the performance of computational methods, including dispersion-corrected B3LYP and B2PLYP functionals, is also included.
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OBJECTIVE: The aim of the study is to compare the results of five years follow-up prospective study of vaginal prolapse repaired by prolift total mesh surgery or sacrospinous fixation. STUDY DESIGN: A single-center prospective, cohort study, in patients with defect grade II and more by POP-Q. SETTING: The Institute for the Care of Mather and Child; 3rd Medical Faculty Charles university, Prague. METHODS: Comparison of the preoperative state and the five years after the operation according POP Q, ICIQ-SF, PISQ 12, VAS. Comparison of intraoperative and postoperative complications. RESULTS: The study was attended by 142 patients; 75 patients underwent surgery Prolift Total and 67 patients sacrospinous fixation by Amreich Richter. On clinical examination at 5-year follow-up, we observed 15 (20.0%) case of anatomical failure in the Prolift group and 30 (44.8%) in the SSF group. Anatomic failure was defined clinically as Ba, C or Bp at the hymen or below. In assessing the overall condition before and five years after surgery using a VAS occurred in patients in the cohort Prolift Total decrease to 2.9 (± 1.9) from the original 7.8 (± 1.8). VAS in SSF group decreased after 5 years to 4.2 (± 2.7) of the original 7.8 (± 1.4). Values ICIQ-SF, analyzing the state of voiding PT group showed a decline from the original 6.7 (± 6.9) to 5.5 (± 5.3). A similar trend was evident even after the SSF. Parameters questionnaire PISQ-12 showed a positive increase from the original 28.6 (± 9.5) to 31.8 (± 7.9) points. PISQ-12 was improved from 28.7 (± 9.8) to 32.2 (± 7.5). CONCLUSION: Recurrences were observed more frequently in patients after sacrospinous fixation, while the quality of life questionnaires yielded comparable postoperative results. Quantity of intraoperative complications is low and both groups do not differ.
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Procedimentos Cirúrgicos em Ginecologia/métodos , Prolapso de Órgão Pélvico/cirurgia , Telas Cirúrgicas , Prolapso Uterino/cirurgia , Criança , Estudos de Coortes , Feminino , Seguimentos , Humanos , Prolapso de Órgão Pélvico/psicologia , Estudos Prospectivos , Qualidade de Vida , Resultado do Tratamento , Prolapso Uterino/psicologiaRESUMO
OBJECTIVE: To analyse the results of the long-term prospective follow-up study of vaginal prolapse reconstructed using a Prolift Posterior. STUDY DESIGN: Prospective, cohort study. SETTING: Institute for the Care of Mother and Child, Prague. METHODS: Over a 5-year period (I/2006 - XII/2011) we prospectively followed a cohort of patients with posterior vaginal wall defect who underwent surgical reconstruction using a monofilament polypropylene implant Prolift Posterior (Gynecare, Ethicon, Inc., Piscataway, NJ, USA). Patients were invited for review at six weeks, three months, six months, 12 months and then yearly up to five years. Postoperative follow-up included the clinical examination and subjective evaluation using VAS, PISQ 12 and ICIQ SF. RESULTS: One hundred twenty-four women were included in the study, of which 14 (11.3%) had no prolapse surgery in their health history. There were no concomitant vaginal procedures such as hysterectomy or another implant surgery. The average operation time and blood loss were 64.25 min (min. 10, max. 205 min) and 115 ml (min. 10 ml, max. 1000 ml), respectively. Only one patient had a blood loss 1000 ml. There were no injuries of the urinary bladder or intestines during the needle insertion of the mesh. In the five-year period, the recurrence of posterior vaginal wall defect was observed in 4 cases (3.3%). The average time to the posterior vaginal wall recurrence prolapse was 19.5 months (min. 6, max. 36). De novo prolapse in the anterior compartment was observed in 25 patients (20.5%). CONCLUSION: In this prospective single centre study, we observed anatomical improvement in the implanted compartment with low recurrence rate. During five years follow-up period there was de novo anterior vaginal wall defect observed in 20.5% cases. The question of implant employment in urogynecology remain to be answered, however, our results show that implants have their position in reconstructive surgery.
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Procedimentos Cirúrgicos em Ginecologia/métodos , Prolapso de Órgão Pélvico/cirurgia , Telas Cirúrgicas , Prolapso Uterino/cirurgia , Criança , Estudos de Coortes , Feminino , Seguimentos , Humanos , Estudos Prospectivos , Resultado do TratamentoRESUMO
AIM: To identify morphologic factors affecting aortic expansion in patients with uncomplicated type B aortic dissections. METHODS: Computed tomography data of 24 patients (18 male; median age: 61 years), diagnosed with acute uncomplicated type B aortic dissections between 2002 and 2013, were retrospectively reviewed. All patients had at least two computed tomography angiography scans and six months of uneventful follow-up. Computed tomography scans were assessed by two independent readers with regard to presence and number of entry tears. Thoracic and abdominal aortic diameters were derived using image processing software. RESULTS: Twenty-two of 24 patients showed aortic expansion over a median computed tomography angiographic follow-up of 33.2 months. Annual rates showed an increase of 1.7 mm for total aortic diameter, 2.1 mm for the false and a decrease of -0.4 mm for the true lumen. In three patients (12.5%), aortic diameter exceeded 60 mm during follow-up, and all three patients underwent thoracic endovascular aortic repair. Patients with a maximum aortic diameter <4 cm at baseline showed a significantly higher expansion rate compared to cases with an initial maximum aortic diameter of ≥4 cm (p=0.0471). A median of two entries (range: 1-5) was recognized per patient. Presence of more than two entry tears (n = 13) was associated with faster overall diameter expansion (mean annual rates: 2.18 mm vs. 1.16 mm; p = 0.4556), and decrease of the cross-sectional surface of the true lumen over time (annual rate for > 2 entries vs. ≤2 entries: -7.8 mm2 vs. +37.5 mm2; p = 0.0369). Median size of entry tears was 12 mm (range: 2-53 mm). CONCLUSIONS: The results presented herein suggest that uncomplicated type B aortic dissection patients with more than two entry tears and/or an initial maximum aortic diameter of<4 cm are at risk for aortic dilatation and, therefore, may require stricter follow-up including the possible need for early intervention.
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Aneurisma Aórtico/diagnóstico por imagem , Dissecção Aórtica/diagnóstico por imagem , Aortografia/métodos , Angiografia por Tomografia Computadorizada , Tomografia Computadorizada Multidetectores , Adulto , Idoso , Dissecção Aórtica/terapia , Aneurisma Aórtico/terapia , Doença Crônica , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Fatores de TempoRESUMO
The ultrafast motion of electrons and holes after light-matter interaction is fundamental to a broad range of chemical and biophysical processes. We advanced high-harmonic spectroscopy to resolve spatially and temporally the migration of an electron hole immediately after ionization of iodoacetylene while simultaneously demonstrating extensive control over the process. A multidimensional approach, based on the measurement and accurate theoretical description of both even and odd harmonic orders, enabled us to reconstruct both quantum amplitudes and phases of the electronic states with a resolution of ~100 attoseconds. We separately reconstructed quasi-field-free and laser-controlled charge migration as a function of the spatial orientation of the molecule and determined the shape of the hole created by ionization. Our technique opens the prospect of laser control over electronic primary processes.
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Elastic and inelastic close-coupling (CC) calculations have been used to extract information about the corrugation amplitude and the surface vibrational atomic displacement by fitting to several experimental diffraction patterns. To model the three-dimensional interaction between the He atom and the Bi(111) surface under investigation, a corrugated Morse potential has been assumed. Two different types of calculations are used to obtain theoretical diffraction intensities at three surface temperatures along the two symmetry directions. Type one consists of solving the elastic CC (eCC) and attenuating the corresponding diffraction intensities by a global Debye-Waller (DW) factor. The second one, within a unitary theory, is derived from merely solving the inelastic CC (iCC) equations, where no DW factor is necessary to include. While both methods arrive at similar predictions for the peak-to-peak corrugation value, the variance of the value obtained by the iCC method is much better. Furthermore, the more extensive calculation is better suited to model the temperature induced signal asymmetries and renders the inclusion for a second Debye temperature for the diffraction peaks futile.
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All attosecond time-resolved measurements have so far relied on the use of intense near-infrared laser pulses. In particular, attosecond streaking, laser-induced electron diffraction and high-harmonic generation all make use of non-perturbative light-matter interactions. Remarkably, the effect of the strong laser field on the studied sample has often been neglected in previous studies. Here we use high-harmonic spectroscopy to measure laser-induced modifications of the electronic structure of molecules. We study high-harmonic spectra of spatially oriented CH3F and CH3Br as generic examples of polar polyatomic molecules. We accurately measure intensity ratios of even and odd-harmonic orders, and of the emission from aligned and unaligned molecules. We show that these robust observables reveal a substantial modification of the molecular electronic structure by the external laser field. Our insights offer new challenges and opportunities for a range of emerging strong-field attosecond spectroscopies.
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We report the observation of macroscopic field-free orientation, i.e., more than 73% of CO molecules pointing in the same direction. This is achieved through an all-optical scheme operating at high particle densities (>10(17) cm(-3)) that combines one-color (ω) and two-color (ω+2ω) nonresonant femtosecond laser pulses. We show that the achieved orientation solely relies on the hyperpolarizability interaction as opposed to an ionization-depletion mechanism, thus, opening a wide range of applications. The achieved strong orientation enables us to reveal the molecular-frame anisotropies of the photorecombination amplitudes and phases caused by a shape resonance. The resonance appears as a local maximum in the even-harmonic emission around 28 eV. In contrast, the odd-harmonic emission is suppressed in this spectral region through the combined effects of an asymmetric photorecombination phase and a subcycle Stark effect, generic for polar molecules, that we experimentally identify.
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The Sb(111) surface was studied with helium atom scattering (HAS). Elastic HAS at different energies of the incident helium beam (15.3, 21.9, 28.4 meV) was applied for structural investigations. The lattice constants derived from the positions of the observed diffraction peaks up to third order were found to be in perfect agreement with previous structure determinations of Sb(111). The observed diffraction patterns with clear peaks up to second order were used to model the electronic surface corrugation with the GR method. As an estimation for the attractive part of the interaction potential a well depth of (4.0 ± 0.5) meV was found. Best fit results were obtained with a corrugation height of 12-13% of the lattice constant, which is rather large compared to other surfaces with metallic character. Intensity measurements of the specular peak as a function of incident energy were analysed to determine the distribution of terraces on the surface. The results show a quite flat Sb(111) surface and a step height of 3.81 Å of the remaining terraces.
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We introduce and demonstrate a new approach to measuring coherent electron wave packets using high-harmonic spectroscopy. By preparing a molecule in a coherent superposition of electronic states, we show that electronic coherence opens previously unobserved high-harmonic-generation channels that connect distinct but coherently related electronic states. Performing the measurements in dynamically aligned nitric oxide molecules we observe the complex temporal evolution of the electronic coherence under coupling to nuclear motion. Choosing a weakly allowed transition to prepare the wave packet, we demonstrate an unprecedented sensitivity that arises from optical interference between coherent and incoherent pathways. This mechanism converts a 0.1% excitation fraction into a â¼20% signal modulation.
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In addition to the local barber surgeons, operations in Ulm were also carried out by travelling lithotomists, or wound physicians, who moved from town to town. The Ulm public medical officer Johannes Scultetus (1595-1645) was of nationwide medical historical importance and whose work"Wundartzneyisches Zeughauß" which was published posthumously was a milestone in surgical literature and included the technique for lithotomy. In the nineteenth century Ulm was the endemic region for urolithiasis and some physicians from the Ulm region were considered to be the most experienced lithotomists. At the end of the Ulm lithotomy period there were various physicians from the Palm family and amongst these Johannes Palm was particularly outstanding. The normal methods of lithotomy used in the nineteenth century varied mainly in the access route to the bladder. The only remaining evidence of the old lithotomists is the classical lithotomy position in the operating room.
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Cirurgiões Barbeiros/história , Litotripsia/história , Procedimentos Cirúrgicos Urológicos/história , Urologia/história , Alemanha , História do Século XVII , HumanosRESUMO
We demonstrate direct amplitude shaping of high harmonics (HHs) using a reflective micromirror array based on micro-electromechanical-system (MEMS) technology. We show independent control over the intensity of each HH in the observed range (14 - 36 eV). These results are used to calculate the control achieved over the temporal structure of the attosecond pulses in the train.
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The Bi(111) surface was studied by elastic scattering of helium atoms at temperatures between 118 and 423 K. The observed diffraction patterns with clear peaks up to third order were used to model the surface corrugation using the eikonal approximation as well as the GR method. Best fit results were obtained with a rather large corrugation height compared to other surfaces with metallic character. The corrugation shows a slight enhancement of the surface electron density in between the positions of the surface atoms. The vibrational dynamics of Bi(111) were investigated by measurements of the Debye-Waller attenuation of the elastic diffraction peaks and a surface Debye temperature of (84 ± 8) K was determined. A decrease of the surface Debye temperature at higher temperatures that was recently observed on Bi nanofilms could not be confirmed in the case of our single-crystal measurements.
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We study the emission of even and odd high-harmonic orders from oriented OCS molecules. We use an intense, nonresonant femtosecond laser pulse superimposed with its phase-controlled second harmonic field to impulsively align and orient a dense sample of molecules from which we subsequently generate high-order harmonics. The even harmonics appear around the full revivals of the rotational dynamics. We demonstrate perfect coherent control over their intensity through the subcycle delay of the two-color fields. The odd harmonics are insensitive to the degree of orientation, but modulate with the degree of axis alignment, in agreement with calculated photorecombination dipole moments. We further compare the shape of the even and odd harmonic spectra with our calculations and determine the degree of orientation.