High-energy molecular-frame photoelectron angular distributions: a molecular bond-length ruler.

We present a study on molecular-frame photoelectron angular distributions (MFPADs) of small molecules using circularly polarized synchrotron light. We find that the main forward-scattering peaks of the MFPADs are slightly tilted with respect to the molecular axis. This tilt angle is directly connected to the molecular bond length by a simple, universal formula. We apply the derived formula to several examples of MFPADs of C 1s and O 1s photoelectrons of CO, which have been measured experimentally or obtained by means of ab initio modeling. In addition, we discuss the influence of the back-scattering contribution that is superimposed over the analyzed forward-scattering peak in the case of homo-nuclear diatomic molecules such as N2.

Investigating charge-up and fragmentation dynamics of oxygen molecules after interaction with strong X-ray free-electron laser pulses.

During 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. Here, we demonstrate that by analyzing photoelectron angular emission distributions and kinetic energy release of charge states of ionic molecular fragments, we can obtain a detailed understanding of the charge-up and fragmentation dynamics. Our novel approach allows for gathering such information without the need of complex ab initio modeling. As an example, we provide a detailed view on the processes happening on a femtosecond time scale in oxygen molecules exposed to intense XFEL pulses.

Fourfold Differential Photoelectron Circular Dichroism.

We report on a joint experimental and theoretical study of photoelectron circular dichroism (PECD) in methyloxirane. By detecting O 1s photoelectrons in coincidence with fragment ions, we deduce the molecule's orientation and photoelectron emission direction in the laboratory frame. Thereby, we retrieve a fourfold differential PECD clearly beyond 50%. This strong chiral asymmetry is reproduced by ab initio electronic structure calculations. Providing such a pronounced contrast makes PECD of fixed-in-space chiral molecules an even more sensitive tool for chiral recognition in the gas phase.

Diagnostic Value of Dynamic High-frequency Ultrasound for the Slipping Rib and Twelfth Rib Syndrome: A Case Series with Review.

BACKGROUND: High-frequency ultrasound (HFUS) is a mobile, radiation-free imaging tool for the diagnosis of musculoskeletal disorders. We aim to demonstrate the diagnostic value of dynamic HFUS for undiagnosed lower chest, upper abdomen, and loin pain with this case series. CASE SERIES: A cricketer presented with long-standing left-sided dull ache lower chest and upper abdominal pain, aggravated on exertion and leaning forward. His previous laboratory and previous imaging tests were unrevealing. Dynamic HFUS of his left ribs during hooking maneuver demonstrated slipping of the eighth rib over the seventh rib associated with clicking. He also reported tenderness over this region. He was diagnosed with slipping rib syndrome (SRS), and was treated with the eighth nerve block under the HFUS guidance. The second and third cases presented with chronic undiagnosed waxing and waning loin pain despite extensive laboratory and radiological workup. Both patients demonstrated twelfth rib HFUS probe tenderness in a sitting position with a specific movement that reproduced the pain during the dynamic HFUS study. The diagnosis of twelfth rib syndrome (TRS) was confirmed and treated successfully with a local intercostal nerve block. REVIEW OF THE LITERATURE: HFUS is the most underutilized imaging tool for the diagnosis of unexplained upper abdominal and lower chest pain syndromes. We identified only a few such reported cases managed with the help of HFUS. CONCLUSION: The dynamic HFUS is a valuable imaging modality for the undiagnosed lower chest, upper abdominal, or loin pain.

[Antihypertensive treatment with nitrendipine]. / Trattamento antipertensivo con nitrendipina.

The effects of nitrendipine (20 mg) were examined in 30 patients suffering from slight to moderate arterial hypertension. Active treatment with nitrendipine (in a single daily dose of 20 mg) continued for 90 days. The administration of the drug in a single dose enabled good control of blood pressure levels to be achieved in 80% of cases (p < 0.059).