Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy.

The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.

A high-resolution combined scanning laser and widefield polarizing microscope for imaging at temperatures from 4 K to 300 K.

Polarized light microscopy, as a contrast-enhancing technique for optically anisotropic materials, is a method well suited for the investigation of a wide variety of effects in solid-state physics, as, for example, birefringence in crystals or the magneto-optical Kerr effect (MOKE). We present a microscopy setup that combines a widefield microscope and a confocal scanning laser microscope with polarization-sensitive detectors. By using a high numerical aperture objective, a spatial resolution of about 240 nm at a wavelength of 405 nm is achieved. The sample is mounted on a 4He continuous flow cryostat providing a temperature range between 4 K and 300 K, and electromagnets are used to apply magnetic fields of up to 800 mT with variable in-plane orientation and 20 mT with out-of-plane orientation. Typical applications of the polarizing microscope are the imaging of the in-plane and out-of-plane magnetization via the longitudinal and polar MOKE, imaging of magnetic flux structures in superconductors covered with a magneto-optical indicator film via the Faraday effect, or imaging of structural features, such as twin-walls in tetragonal SrTiO3. The scanning laser microscope furthermore offers the possibility to gain local information on electric transport properties of a sample by detecting the beam-induced voltage change across a current-biased sample. This combination of magnetic, structural, and electric imaging capabilities makes the microscope a viable tool for research in the fields of oxide electronics, spintronics, magnetism, and superconductivity.

Gastroschisis: a multi-centre comparison of management and outcome.

BACKGROUND: Anecdotal evidence and a handful of literature reports suggest that the outcome for infants born with gastroschisis in many African countries is poor when compared to Western nations. We wished to evaluate current management strategies and outcomes in African and Western units that treat infants with gastroschisis. PATIENTS AND METHODS: We conducted a retrospective review of case-notes for infants with gastroschisis who presented to a hospital between 1 January 2004 and 31 December 2007. There were five participating centres, divided for analysis into an African cohort (three centres) and a Western cohort (two centres). RESULTS: Fewer infants presented to a hospital with gastroschisis in the African cohort when compared to the Western cohort, particularly when the size of catchment area of each hospital was taken into account. The physiological state of the infant on presentation and management strategy varied widely between centres. Primary closure, preformed silo and surgical silo with delayed closure were all utilised in the African cohort. Use of the preformed silo and delayed abdominal wall closure was the strategy of choice in the Western cohort. The 30-day mortality was 23% and 1% respectively. This primary outcome measure varied considerably in the African cohort but was the same in the two Western units. CONCLUSIONS: Gastroschisis in the African cohort was characterised by fewer infants presenting to a hospital and a more variable outcome when compared to the Western cohort. A detailed epidemiological study to determine the incidence of gastroschisis in African countries may provide valuable information. In addition, interventions such as prompt resuscitation, safe neonatal transfer, the use of the preformed silo and parenteral nutrition could improve outcomes in infants with gastroschisis.

SU-E-J-57: MRI-Linac (MRL) Guided Treatment for Esophageal Cancer.

For radiotherapy, oesophageal cancer is located in a difficult area. Spatial control of the dose distribution is difficult to achieve with current CT-based radiation techniques, as on CT, soft-tissue contrast is too low. Furthermore, the oesophagus moves and organs at risk (e.g. lung, heart, liver, spinal cord) are in close proximity. An 1.5 T MRI-accelerator (MRL) has sufficient soft-tissue tumour visualization possibilities to allow for precise real-time, online, position verification and for dose escalation without organ at riskoverdose. Our research consists of the preparatory work for the first clinical study on the MRL for patients with oesophageal cancer. To improve image quality and reduce the motion artefacts, the benefit of cardiac triggering and breath holds is evaluated on fifteen oesophageal patients. Results show the superb image quality of these MRI sequences. The use of this high quality MRI gives the possibility for non-invasive real-time visualization andtracking of the tumour. We quantify oesophageal tumour motion on cineMRI. The tumour is tracked on sequential mixed T1/T2w images (acquisition time: 60s, temporal resolution: 0.5s, slice thickness: 7mm) of a single coronal and sagittal slice using a Minimum Output Sum of Squared Error (MOSSE) adaptive correlation filter. Tumour registration within the individual images can typically be done at a millisecond time scale. Motion of oesophageal tumours can well be tracked and is highly variable between patients. The greatest mobility is seen in cranio-caudal direction, with amaximum peak-to-peak amplitude of tumour movement of 24.5mm followed by the dorso-ventral and the medio-lateral direction. Movement seems greatest in tumours located in the lower part of the oesophagus. This study shows both the superb image quality for GTV localisation and the possibility for on-line and real time tumour tracking. The study opens thepossibility for tracked radiation delivery with a 1.5T MRI accelerator. Partial funding has been obtained by Elekta and Philips.

Travel associated legionnaires' disease in Europe in 2000 and 2001.

The European Surveillance Scheme for Travel Associated Legionnaires' Disease (EWGLINET) was notified of 360 cases in 2000 and 481 cases in 2001, the highest number reported since 1987. This increase reflects enhanced surveillance activities, especially in the Netherlands, France and Italy, mainly through urinary antigen detection test (78% of cases in 2001). The median delay in reporting to the scheme fell to under 30 days, at the cost of some loss of information on the outcomes of illness. In 2000, 28 clusters were detected compared to 72 in 2001, most of this rise resulting from a change in the definition of clusters. In 2000 and 2001, 55 and 140 environmental investigations were reported respectively.

Travel associated legionnaires' disease in Europe in 1999.

The European Surveillance Scheme for Travel Associated Legionnaires' Disease was notified of the highest number of cases in travellers in 1999 since the scheme began in 1987. This reflects enhanced surveillance activities and an increase in the use of urinary antigen detection for Legionella pneumophila serogroup 1. The scheme's extensive reporting and investigation activities are complemented in some countries by the activities of tour operators, who have been legally responsible for the health and safety of their clients since the 1996 European Commission's Package Travel Directive came into force. In recent years, the work conducted by the collaborators has helped establish good surveillance and control in sites used by travellers.