22 research outputs found
Observation of enhanced chiral asymmetries in the inner-shell photoionization of uniaxially oriented methyloxirane enantiomers
Most large molecules are chiral in their structure: they exist as two
enantiomers, which are mirror images of each other. Whereas the rovibronic
sublevels of two enantiomers are almost identical, it turns out that the
photoelectric effect is sensitive to the absolute configuration of the ionized
enantiomer - an effect termed Photoelectron Circular Dichroism (PECD). Our
comprehensive study demonstrates that the origin of PECD can be found in the
molecular frame electron emission pattern connecting PECD to other fundamental
photophysical effects as the circular dichroism in angular distributions
(CDAD). Accordingly, orienting a chiral molecule in space enhances the PECD by
a factor of about 10
Harmonic Vibrational Excitations in Disordered Solids and the "Boson Peak"
We consider a system of coupled classical harmonic oscillators with spatially
fluctuating nearest-neighbor force constants on a simple cubic lattice. The
model is solved both by numerically diagonalizing the Hamiltonian and by
applying the single-bond coherent potential approximation. The results for the
density of states are in excellent agreement with each other. As
the degree of disorder is increased the system becomes unstable due to the
presence of negative force constants. If the system is near the borderline of
stability a low-frequency peak appears in the reduced density of states
as a precursor of the instability. We argue that this peak
is the analogon of the "boson peak", observed in structural glasses. By means
of the level distance statistics we show that the peak is not associated with
localized states
Imaging the square of the correlated two-electron wave function of a hydrogen molecule
The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. Molecules are many-body systems for which the correlation between the constituents is decisive and the spatial and the momentum distribution of one electron depends on those of the other electrons and the nuclei. Such correlations have escaped direct observation by imaging techniques so far. Here, we implement an imaging scheme which visualizes correlations between electrons by coincident detection of the reaction fragments after high energy photofragmentation. With this technique, we examine the H2 two-electron wave function in which electron-electron correlation beyond the mean-field level is prominent. We visualize the dependence of the wave function on the internuclear distance. High energy photoelectrons are shown to be a powerful tool for molecular imaging. Our study paves the way for future time resolved correlation imaging at FELs and laser based X-ray sources.This work was funded by the Deutsche Forschungsgemeinschaft, the BMBF, the European Research Council under the European Union Seventh Framework Programme
(FP7/2007-2013)/ERC grant agreement 290853 XCHEM, the MINECO projects
FIS2013-42002-R and FIS2016-77889-R, and the European COST Action XLIC CM1204.
All calculations were performed at the CCC-UAM and Mare Nostrum Supercomputer
Centers. We are grateful to the staff of PETRA III for excellent support during the beam
time. K.M. and M.M. would like to thank the DFG for support via SFB925/A3. A.K. and
V.S. thank the Wilhelm und Else Heraeus-Foundation for support. J.L. would like to
thank the DFG for support. S.K. acknowledges support from the European Cluster of
Advanced Laser Light Sources (EUCALL) project which has received funding from the European Unionâs Horizon 2020 research and innovation programme under grant
agreement No 654220. T.W. was supported by the U.S. Department of Energy Basic
Energy Sciences under Contract No. DE-AC02-05CH11231. A.P. acknowledges a RamĂłn
y Cajal contract from the Ministerio de Economa y Competitividad. We thank M. LaraAstiaso for providing us with the HartreeâFock wave functions
Neutrophil microvesicles drive atherosclerosis by delivering <i>miR-155</i> to atheroprone endothelium
Neutrophils are implicated in the pathogenesis of atherosclerosis but are seldom detected in atherosclerotic plaques. We investigated whether neutrophil-derived microvesicles may influence arterial pathophysiology. Here we report that levels of circulating neutrophil microvesicles are enhanced by exposure to a high fat diet, a known risk factor for atherosclerosis. Neutrophil microvesicles accumulate at disease-prone regions of arteries exposed to disturbed flow patterns, and promote vascular inflammation and atherosclerosis in a murine model. Using cultured endothelial cells exposed to disturbed flow, we demonstrate that neutrophil microvesicles promote inflammatory gene expression by delivering miR-155, enhancing NF-ÎșB activation. Similarly, neutrophil microvesicles increase miR-155 and enhance NF-ÎșB at disease-prone sites of disturbed flow in vivo. Enhancement of atherosclerotic plaque formation and increase in macrophage content by neutrophil microvesicles is dependent on miR-155. We conclude that neutrophils contribute to vascular inflammation and atherogenesis through delivery of microvesicles carrying miR-155 to disease-prone regions
Spectrum of pheochromocytoma in the 131 I-MIBG era
131 I-metaiodobenzylguanidine ( 131 I-MIBG) scintigraphy allows for both functional diagnosis and anatomical localization of pheochromocytoma. The spectrum of pheochromocytoma since the routine use of preoperative 131 I-MIBG scan was studied. From 1980 to 1986, a total of 34 patients were primarily diagnosed and treated at the University of Michigan Medical Center, Ann Arbor, Michigan, U.S.A. There were 16 males and 18 females. The mean age was 38 years and 4 patients (11.8%) were under 18 years of age. Six patients (17.6%) had family history of pheochromocytoma or multiple endocrine neoplasia (MEN) II syndrome. The presenting symptoms were hypertension in 29 patients (85.3%); attacks of headache, palpitation, sweating, and flushing in 4 (11.8%), and 1 patient presented with a neck mass. Plasma catecholamines were elevated in 97% of patients while urinary catecholamines and metabolites were elevated in 93.5%. 131 I-MIBG was accurate in 82.3%, partly positive in 11.8%, and false-negative in 5.9% of patients. CT scan was accurate in 80%, partly positive in 10%, but failed to show the tumor in another 10% of patients. At operation, extraadrenal lesions were found in 38.2% of the patients and among these, one-third were extraabdominal. Multiple tumors occurred in 5 (14.7%), and bilateral adrenal lesions occurred in 4 patients (11.8%). Malignancy was diagnosed in 3 patients (8.8%) after an average follow-up period of 2 years. We conclude that the use of routine preoperative 131 I-MIBG scanning improves localization of pheochromocytoma and earlier diagnosis is possible in patients with MEN II syndrome. Multiple tumors, extraadrenal and extraabdominal lesions occur more often than commonly believed. The low rate of confirmed malignancy is probably related to the short period of follow-up. La scintigraphie Ă l' 131 I-MIBG permet de diagnostiquer et de localiser les phĂ©ochromocytomes. Toute la gamme de types de phĂ©ochromocytomes reconnu depuis l'utilisation prĂ©opĂ©ratoire systĂ©matique de la scintigraphie Ă l' 131 I-MIBG est prĂ©sentĂ©e. Entre 1980 et 1986, 34 patients ont Ă©tĂ© explorĂ©s et traitĂ©s au Centre MĂ©dical de l'UniversitĂ© de Michigan, Ann Arbor, Michigan. Il y avait 16 hommes et 18 femmes. L'Ăąge moyen Ă©tait de 38 ans, et 4 patients (11.8%) avaient moins de 18 ans. Six patients (17.6%) avaient des antĂ©cĂ©dents familiaux de phĂ©ochromocytome ou de nĂ©oplasmes endocrines multiples (MEN) du type II. Les symptĂŽmes amenant Ă consulter Ă©taient l'hypertension chez 29 patients (85.3%), des crises de cĂ©phalĂ©es, des palpitations et un flush chez 4 patients (11.8%); un patient prĂ©sentait une masse cervicale. Les catĂ©cholamines plasmatiques Ă©taient Ă©levĂ©es chez 97% des patients alors que les catĂ©cholamines et leurs mĂ©tabolites Ă©taient en quantitĂ© Ă©levĂ©e chez 93.5% des patients. La scintigraphie Ă l' 131 I-MIBG Ă©tait positive chez 82.3%, partiellement positive chez 11.8%, et faussement nĂ©gative chez 5.9% des patients. La tomodensitomĂ©trie Ă©tait positive chez 80%, partiellement positive chez 10%, et faussement nĂ©gative chez 10% des patients. A l'intervention, des lĂ©sions extra-surrĂ©nales Ă©taient prĂ©sentes dans 38.2% des cas, et parmi celles-ci, un tiers Ă©taient extra-abdominales. Les tumeurs Ă©taient multiples dans 5 cas (14.7%), et bilatĂ©rales surrĂ©nales dans 4 cas (11.8%). Une tumeur maligne Ă©tait diagnostiquĂ©e chez 3 patients (8.8%), aprĂšs une pĂ©riode de suivi de 2 ans en moyenne. Nous concluons que l'utilisation systĂ©matique de la scintigraphie Ă l' 131 I-MIBG amĂ©liore la localisation des phĂ©ochromocytomes, permettant un diagnostic plus prĂ©coce chez les patients prĂ©sentant un syndrome MEN II. La multiplicitĂ© tumorale et les localisations extra-mĂ©dullosurrĂ©nales ou extra-abdominales se voient beaucoup plus frĂ©quemment qu'on le pensait auparavant. Le taux de malignitĂ© peu Ă©levĂ© Ă©tait probablement en rapport avec la courte pĂ©riode de suivi. La escintigrafĂa con 131 I-MIBG permite tanto la localizaciĂłn anatĂłmica como el diagnĂłstico funcional del feocromocitoma. Las caracterĂsticas o espectro del feocromocitoma a partir del uso rutinario de 131 I-MIBG han sido estudiadas.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41282/1/268_2005_Article_BF01655447.pd
Three Simple Software Extensions for Automatic Presentation of Radiation Induced Toxicity, Sequelae and Treatment Outcomes, for Increasing Safety in Daily Therapeutic Routine, and for Enhancing Patient Comfort
Background: Simple software extensions to already existing software-infrastructure can monitor treatment results, increase patient safety and enhance patient comfort in a very cost-effective way. This is of particular interest due to the increasing implementation of quality management in radiotherapeutic treatment sites as well as due to the external cooperation in cancer centers. In this article, we present three different tools.Results: First, âToxReviewâ is a program extension to âMOSAIQâ 02.10. It correlates automatically radiation induced toxicity and treatment outcomes with therapeutic concepts (target volumes, radiation doses etc.). Data are shown in a simple tabular form.Second, âPatient Recognitionâ is a JAVA based program extension that aims to minimize the risk of mix-ups between patients. It does not need a MOSAIQ license. It identifies the actual patient uploaded in the treatment control station. On a monitor next to the treatment room entrance a portrait and the name of this patient is shown, enabling the assistance staff and the patient himself to check that his specific data are uploaded.Third, the add-on âJukeboxâ enables to play patient individualized music and entertainment programs in the radiation room during treatment. No additional efforts are necessary for the assistance staff. Conclusion: We present customer programmable software extensions with high value in daily clinical practice, to expand the possibilities of the pre-existing IT infrastructure.Quality management,patient safety and patient satisfaction are substantially increased. </p
Imaging the square of the correlated two-electron wave function of a hydrogen molecule (vol 8, 2018) [Publisher Correction]
Correction to: Nature Communications https://doi.org/10.1038/s41467-017-02437-9, published online 22 December 2017
The original version of this Article contained an error in the fifth sentence of the first paragraph of the âApplication on H2â section of the Results, which incorrectly read âThe role of electron correlation is quite apparent in this presentation: Fig. 1a is empty for the uncorrelated HartreeâFock wave function, since projection of the latter wave function onto the 2pÏu orbital is exactly zero, while this is not the case for the fully correlated wave function (Fig. 1d); also, Fig. 1b, c for the uncorrelated description is identical, while Fig. 1e, f for the correlated case is significantly different.â The correct version replaces âFig. 1e, fâ with âFig. 2e, fâ.
This has been corrected in both the PDF and HTML versions of the Article
Publisher correction : imaging the square of the correlated two-electron wave function of a hydrogen molecule
Correction to: Nature Communications https://doi.org/10.1038/s41467-017-02437-9, published online 22 December 201