We report a fully differential study of ionization of the Ne L shell by Compton scattering of 20 keV photons. We find two physical mechanisms that modify the Compton-electron emission. Firstly, we observe scattering of the Compton electrons at their parent nucleus.
View Article and Find Full Text PDFWe experimentally study the influence of the binding energy on nondipole effects in K-shell single-photon ionization of atoms at high photon energies. We find that for each ionization event, as expected by momentum conservation, the photon momentum is transferred almost fully to the recoiling ion. The momentum distribution of the electrons becomes asymmetrically deformed along the photon propagation direction with a mean value of 8/(5c)(E_{γ}-I_{P}) confirming an almost 100 year old prediction by Sommerfeld and Schur [Ann.
View Article and Find Full Text PDFThe recent implementation of attosecond and few-femtosecond X-ray pump/X-ray probe schemes in large-scale free-electron laser facilities has opened the way to visualize fast nuclear dynamics in molecules with unprecedented temporal and spatial resolution. Here, we present the results of theoretical calculations showing how polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) can be used to visualize the dynamics of hydrogen migration in methanol, ethanol, propanol, and isopropyl alcohol dications generated by X-ray irradiation of the corresponding neutral species. We show that changes in the PA-MFPADs with the pump-probe delay as a result of intramolecular photoelectron diffraction carry information on the dynamics of hydrogen migration in real space.
View Article and Find Full Text PDFWe investigate experimentally and theoretically the C and O 1s photoionization of fixed-in-space CO molecules at a photon energy of 905 eV. We find a significant dependence of the photoelectron angular distributions on the direction of propagation of the ionizing radiation. It results from an interplay of nondipole effects, on one hand, and molecular effects, on the other.
View Article and Find Full Text PDFDuring the last decade, X-ray free-electron lasers (XFELs) have enabled the study of light-matter interaction under extreme conditions. Atoms which are subject to XFEL radiation are charged by a complex interplay of (several subsequent) photoionization events and electronic decay processes within a few femtoseconds. The interaction with molecules is even more intriguing, since intricate nuclear dynamics occur as the molecules start to dissociate during the charge-up process.
View Article and Find Full Text PDFBottlenecks in the efficient conversion of xylose into cost-effective biofuels have limited the widespread use of plant lignocellulose as a renewable feedstock. The yeast Saccharomyces cerevisiae ferments glucose into ethanol with such high metabolic flux that it ferments high concentrations of glucose aerobically, a trait called the Crabtree/Warburg Effect. In contrast to glucose, most engineered S.
View Article and Find Full Text PDFWe report on a multiparticle coincidence experiment performed at the European X-ray Free-Electron Laser at the Small Quantum Systems instrument using a COLTRIMS reaction microscope. By measuring two ions and two electrons in coincidence, we investigate double core-hole generation in O_{2} molecules in the gas phase. Single-site and two-site double core holes have been identified and their molecular-frame electron angular distributions have been obtained for a breakup of the oxygen molecule into two doubly charged ions.
View Article and Find Full Text PDFPhotoionization is one of the fundamental light-matter interaction processes in which the absorption of a photon launches the escape of an electron. The time scale of this process poses many open questions. Experiments have found time delays in the attosecond (10 seconds) domain between electron ejection from different orbitals, from different electronic bands, or in different directions.
View Article and Find Full Text PDFWe experimentally investigate the effects of the linear photon momentum on the momentum distributions of photoions and photoelectrons generated in one-photon ionization in an energy range of 300 eV≤E_{γ}≤40 keV. Our results show that for each ionization event the photon momentum is imparted onto the photoion, which is essentially the system's center of mass. Nevertheless, the mean value of the ion momentum distribution along the light propagation direction is backward-directed by -3/5 times the photon momentum.
View Article and Find Full Text PDFWe investigate angular emission distributions of the 1s photoelectrons of N_{2} ionized by linearly polarized synchrotron radiation at hν=40 keV. As expected, nondipole contributions cause a very strong forward-backward asymmetry in the measured emission distributions. In addition, we observe an unexpected asymmetry with respect to the polarization direction, which depends on the direction of the molecular fragmentation.
View Article and Find Full Text PDFPhys Rev Lett
November 2019
We investigate K-shell ionization of N_{2} at 40 keV photon energy. Using a cold target recoil ion momentum spectroscopy reaction microscope, we determine the vector momenta of the photoelectron, the Auger electron, and both N^{+} fragments. These fully differential data show that the dissociation process of the N_{2}^{2+} ion is significantly modified not only by the recoil momentum of the photoelectron but also by the photon momentum and the momentum of the emitted Auger electron.
View Article and Find Full Text PDFWe report on the nonadiabatic offset of the initial electron momentum distribution in the plane of polarization upon single ionization of argon by strong field tunneling and show how to experimentally control the degree of nonadiabaticity. Two-color counter- and corotating fields (390 and 780 nm) are compared to show that the nonadiabatic offset strongly depends on the temporal evolution of the laser electric field. We introduce a simple method for the direct access to the nonadiabatic offset using two-color counter- and corotating fields.
View Article and Find Full Text PDFJ Eur Acad Dermatol Venereol
June 2015
Background: In addition to physical long-lasting effects such as permanent scarring and disfigurement, acne has acute and long-term psychosocial effects that affect the individual's quality of life. As with other chronic diseases, treatment success is often compromised by poor adherence.
Objective: Two main objectives of this non-interventional study were to assess the long-term effect of the fixed-dose combination adapalene 0.
Background: Acne is a chronic inflammatory disease requiring long-term treatment. The fixed-dose combination adapalene 0.1%/benzoyl peroxide 2.
View Article and Find Full Text PDFThe mycoses selected for presentation in this section are relatively common diseases of companion animals or livestock in certain areas of the world. Malasseziosis is arguably the most frequent mycosis of dogs (as otitis externa and dermatitis) throughout the world, although its diagnosis is often overlooked. Protothecosis is also geographically widespread, particularly in cattle where severe mastitis is a result of adventitious infection from the environment.
View Article and Find Full Text PDFThe application of an adjustable silicone gastric band is a very efficient and long-term method to reduce the weight in morbid obesity. The surgical technique is exacting; standardization of the procedure diminishes the complication rate. 370 patients with morbid obesity underwent the laparoscopic application of a gastric band between May 1996 and September 1997.
View Article and Find Full Text PDFDuring late May 1995, 50 adult captive endangered Wyoming toads (Bufo baxteri) were brought out of hibernation. Approximately 3 to 10 days after hibernation emergence, all toads were hormonally induced to breed, and paired. Each pair was placed in their own breeding tank.
View Article and Find Full Text PDFWyoming toads (Bufo baxteri) that died from January 1989 to June 1996 were submitted to the Wyoming State Veterinary Laboratory (Laramie, Wyoming, USA) for postmortem evaluation. These consisted of 108 free-ranging toads and 170 animals from six captive populations. Ninety-seven (90%) of 108 free-ranging toad carcasses were submitted during September and October.
View Article and Find Full Text PDFCats are often cited as reservoirs of M. canis but it is questionable whether M. canis is part of the resident flora of the cat's skin and hair or only a transient organism.
View Article and Find Full Text PDFLangenbecks Arch Chir Suppl Kongressbd
April 1999
Kuzmak's adjustable gastric banding procedure is well established and has proven to be efficacious in obese patients. After gastric banding we observed a good weight loss and an improvement in metabolic syndrome diseases. Therefore we were able to reduce the dosage of preoperative medication in patients with diabetes or hypertension.
View Article and Find Full Text PDFLangenbecks Arch Chir Suppl Kongressbd
April 1999
Activated protein C resistance is the most frequent cause of venous thrombosis. We describe a patient with extensive ulcerations and severe lymphedema of the legs after recurrent thrombosis. Laboratory tests revealed a pathologic activated protein C resistance and a reduced functional protein S.
View Article and Find Full Text PDFAn operative technique is described for fasciorrhaphy of large laparoscopic incisions, umbilical hernias or small abdominal wall hernias with laparoscopic monitoring within the scope of minimal invasive surgery. Over a period of 8 months the Carter-Thomason technique was used in 105 operative laparoscopies for occlusion of large laparoscopic incisions and in 6 pre-existing umbilical hernias. In the postoperative period no hernias occurred and no complications were observed.
View Article and Find Full Text PDFA total of 701 patients operated on with the suspected diagnosis of acute appendicitis were included in a prospective study. Three hundred and nine patients were treated conventionally and 387 laparoscopically. In 14 patients the operation had to be converted.
View Article and Find Full Text PDFZentralbl Chir
February 1997
We report on a female patient who was suffering from a duodenal ulcer with an oozing haemorrhage. It turned out to be the result of an adenoma of the parathyroid combined with the clinical picture of an 'osteodystrophia fibrosa cystica generalisata', which is rarely seen. The therapy consisted in a parathyroidectomy.
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