Laser-accelerated electron beams at 1 GeV using optically-induced shock injection.

In recent years, significant progress has been made in laser wakefield acceleration (LWFA), both regarding the increase in electron energy, charge and stability as well as the reduction of bandwidth of electron bunches. Simultaneous optimization of these parameters is, however, still the subject of an ongoing effort in the community to reach sufficient beam quality for next generation's compact accelerators. In this report, we show the design of slit-shaped gas nozzles providing centimeter-long supersonic gas jets that can be used as targets for the acceleration of electrons to the GeV regime. In LWFA experiments at the Centre for Advanced Laser Applications, we show that electron bunches are accelerated to [Formula: see text] using these nozzles. The electron bunches were injected into the laser wakefield via a laser-machined density down-ramp using hydrodynamic optical-field-ionization and subsequent plasma expansion on a ns-timescale. This injection method provides highly controllable quasi-monoenergetic electron beams with high charge around [Formula: see text], low divergence of [Formula: see text], and a relatively small energy spread of around [Formula: see text] at [Formula: see text]. In contrast to capillaries and gas cells, the scheme allows full plasma access for injection, probing or guiding in order to further improve the energy and quality of LWFA beams.

Increasing incidence of chronic subdural haematoma in the elderly.

BACKGROUND: Chronic subdural haematoma (CSDH) is a condition predominantly affecting the elderly. We reported an incidence of 8.2 per 100 000 per year in people above the age of 65 in 2002. AIM: Since recent studies have demonstrated a higher incidence, we repeated our study to estimate the current incidence of CSDH amongst people above the age of 65 in North Wales. DESIGN: We used radiological reports to identify patients with CSDH over a 1-year period. METHODS: We collected data on demographics, clinical presentations, indications for brain imaging, drug history and 30-day outcome from the case notes and electronic records. RESULTS: The population of North Wales was 687 937 of which 138 325 (20%) were above 65. There were 66 cases of CSDH giving an incidence of 48 per 100 000 per year. Mean age was 81 and there were 32 males and 34 females. Falls and confusion were the commonest indications to request a CT scan (90%). Other indications were drowsiness (9%) and focal neurological deficit (4%). 17 were on antiplatelets and 20 were on warfarin. Ten underwent surgical intervention. At 30 days 28 were discharged, 22 were still in hospital and 16 died. CONCLUSION: The incidence of CSDH is much higher than previously reported. Reasons include a low threshold for imaging patients with recurrent falls and confusion, increasing use of anti-thrombotics and ageing population. In many older patients CSDH is a marker of underlying co-morbidities rather than a primary event.

The role of the sid1p kinase and cdc14p in regulating the onset of cytokinesis in fission yeast.

Coordination of mitosis and cytokinesis is crucial for ensuring proper chromosome segregation and genomic stability. In Schizosaccharomyces pombe, the sid genes (cdc7, cdc11, cdc14, spg1, sid1, sid2 and sid4) define a signaling pathway that regulates septation and cytokinesis. Here we describe the characterization of a novel protein kinase, Sid1p. Sid1p localizes asymmetrically to one spindle pole body (SPB) in anaphase. Sid1p localization is maintained during medial ring constriction and septum synthesis and disappears prior to cell separation. Additionally, we found that Cdc14p is in a complex with Sid1p. Epistasis analysis places Sid1p-Cdc14p downstream of Spg1p-Cdc7p but upstream of Sid2p. Finally, we show that cyclin proteolysis during mitosis is unaffected by inactivating the sid pathway; in fact, loss of Cdc2-cyclin activity promotes Sid1p-Cdc14p association with the SPB, possibly providing a mechanism that couples cytokinesis with mitotic exit.

Major pelvic injuries in equestrian sports.

A series of pelvic and acetabular injuries caused by horse riding accidents is reported. The importance of wearing appropriate protective clothing when riding is emphasised.

Reliability of fat-pad sign in radial head/neck fractures of the elbow.

In a prospective study at a single centre between August 1995 and March 1996, 193 patients with elbow injuries were studied. Standard radiographs of the elbows were taken. A total of 181 X-rays were reported by one person concerning the presence or absence of fractures and fat-pad signs. The radiographs were analysed and positive predictive values were calculated for the presence of the fat-pad sign with radial head/neck fractures. The sensitivity for radial head/neck fracture is 85.4 per cent, while the specificity is only 50 per cent. The fat-pad sign must be used cautiously as an indicator of radial head/neck fractures; its absence is a more reliable indicator of the absence of a radial head/ neck fracture.

Trials with an adenosine analogue as antianginal medication.

The potential antianginal effects of orally administered ethyl-adenosine-5-carboxylate hydrochloride (EACH) were assessed in 9 patients with stable angina pectoris who underwent two standardized exercise tests for 3 consecutive days. The first daily exercise performed after placebo revealed no daily variation. The second test was preceded by placebo, 26 mg EACH or 33 mg EACH administered in a double-blind fashion with the use of crossover design. After the completion of the study in the first 6 patients, the 33-mg dose of EACH had to be discontinued because 3 patients had severe angina and another one had nausea and diffuse numbness after this dose. In the remaining 3 patients a 6-mg dose of EACH was used instead of 33 mg, after which the study was terminated because no difference could be determined. EACH, 26-mg and 6-mg, had no significant effect on resting and exercise heart rate, on blood pressure, on onset or duration of angina and positive-exercise electrocardiogram, or on exercise duration. Our study revealed that EACH had no potential antianginal effect and that at a dosage of 33 mg it may induce angina.