Damage mechanisms of MoN/SiN multilayer optics for next-generation pulsed XUV light sources.

We investigated the damage mechanism of MoN/SiN multilayer XUV optics under two extreme conditions: thermal annealing and irradiation with single shot intense XUV pulses from the free-electron laser facility in Hamburg - FLASH. The damage was studied "post-mortem" by means of X-ray diffraction, interference-polarizing optical microscopy, atomic force microscopy, and scanning transmission electron microscopy. Although the timescale of the damage processes and the damage threshold temperatures were different (in the case of annealing it was the dissociation temperature of Mo2N and in the case of XUV irradiation it was the melting temperature of MoN) the main damage mechanism is very similar: molecular dissociation and the formation of N2, leading to bubbles inside the multilayer structure.

Single shot damage mechanism of Mo/Si multilayer optics under intense pulsed XUV-exposure.

We investigated single shot damage of Mo/Si multilayer coatings exposed to the intense fs XUV radiation at the Free-electron LASer facility in Hamburg - FLASH. The interaction process was studied in situ by XUV reflectometry, time resolved optical microscopy, and "post-mortem" by interference-polarizing optical microscopy (with Nomarski contrast), atomic force microscopy, and scanning transmission electron microcopy. An ultrafast molybdenum silicide formation due to enhanced atomic diffusion in melted silicon has been determined to be the key process in the damage mechanism. The influence of the energy diffusion on the damage process was estimated. The results are of significance for the design of multilayer optics for a new generation of pulsed (from atto- to nanosecond) XUV sources.

Spot size characterization of focused non-Gaussian X-ray laser beams.

We present a new technique for the characterization of non-Gaussian laser beams which cannot be described by an analytical formula. As a generalization of the beam spot area we apply and refine the definition of so called effective area (A(eff)) [1] in order to avoid using the full-width at half maximum (FWHM) parameter which is inappropriate for non-Gaussian beams. Furthermore, we demonstrate a practical utilization of our technique for a femtosecond soft X-ray free-electron laser. The ablative imprints in poly(methyl methacrylate) - PMMA and amorphous carbon (a-C) are used to characterize the spatial beam profile and to determine the effective area. Two procedures of the effective area determination are presented in this work. An F-scan method, newly developed in this paper, appears to be a good candidate for the spatial beam diagnostics applicable to lasers of various kinds.

Responsive brushes and gels as components of soft nanotechnology.

Progress in the development of generic molecular devices based on responsive polymers is discussed. Characterisation of specially synthesised polyelectrolyte gels, "grafted from" brushes and triblock copolymers is reported. A Landolt pH-oscillator, based on bromate/ sulfite/ferrocyanide, with a room temperature period of 20 min and a range of 3.1 < pH < 7.0, has been used to drive periodic oscillations in volume in a pH responsive hydrogel. The gel is coupled to the reaction and changes volume by a factor of at least 6. A continuously stirred, constant volume, tank reactor was set-up on an optical microscope and the reaction pH and gel size monitored. The cyclic force generation of this system has been measured directly in a modified JKR experiment. The responsive nature of polyelectrolyte brushes, grown by surface initiated ATRP, have been characterised by scanning force microscopy, neutron reflectometry and single molecule force measurements. Triblock copolymers, based on hydrophobic end-blocks and either polyacid or polybase mid-block, have been used to produce polymer gels where the deformation of the molecules can be followed directly by SAXS and a correlation between molecular shape change and macroscopic deformation has been established. The three systems studied allow both the macroscopic and a molecular response to be investigated independently for the crosslinked gels and the brushes. The triblock copolymers demonstrate that the individual response of the polyelectrolyte molecules scale-up to give the macroscopic response of the system in an oscillating chemical reaction.

Role of fibrin D-dimer testing in emergency medicine.

OBJECTIVES: Systemic values of the fibrinolytic plasma marker fibrin D-dimer are raised in a variety of acute clinical conditions. D-dimer values can now be rapidly determined and used to aid diagnosis in emergency medicine. However, despite clinical guidelines, inappropriate and unnecessary measurement of D-dimer values is a significant clinical problem. An understanding of the pathophysiological basis and limitations of the value of D-dimer values may help reduce this problem. This review discusses the pathophysiology of the fibrinolytic system. The currently used assays, clinical indications, and limitations of D-dimer measurement are reviewed. Finally, the potential future clinical indications for measurement of D-dimer values in emergency medicine are discussed. METHODS: Literature on D-dimer was identified from Medline, along with cross referencing from the reference lists of major articles on the subject RESULTS: and conclusions: Systemic D-dimer values aids diagnosis, and is potentially a prognostic indicator, in a variety of clinical conditions in emergency medicine. However, it has limited specificity in patients with comorbid conditions. Although, currently, there is no standard D-dimer assay, immunoturbidimetric assays are the most suitable for use in emergency medicine

Paediatric liver transplantation [corrected] in Melbourne: the first 50 patients.

To report the outcomes of the first 50 paediatric patients who have undergone liver transplantation (LT) at the Victorian Liver Transplant Unit, a retrospective review of case records was carried out. From December 1988 to December 2000, 108 patients 18 years or younger were referred for LT; 50 of these underwent a total of 53 transplants. The most common indications were biliary atresia (32%), metabolic disease (26%), and acute hepatic necrosis (26%). The majority of deaths (6/7) occurred in the 1st week after LT. The actuarial survival at 1 year was 88% (95% CI 75% to 94%) and at 10 years 85% (95% CI 71% to 93%). Survival rates were highest for children aged 3 to 14 years (95%) and lowest in those weighing less than 8 kg at the time of LT (66%). All 43 survivors are attending age-appropriate activities including kindergarten, school, and employment. The survival of patients undergoing LT in this unit compares favourably with those recorded by the Australia and New Zealand Transplant Registry and is commensurate with that reported by larger paediatric transplant programs overseas.

The relationship between cholesterol absorption and intestinal cholesterol synthesis in the diabetic rat model.

The chylomicron remnant particle is thought to be particularly atherogenic and we have previously shown alterations in post-prandial lipoproteins which could contribute to their atherogenicity. Cholesterol metabolism is disturbed in diabetes, yet the effect of diabetes on intestinal cholesterol synthesis and absorption has rarely been investigated. The aim of this study was to examine cholesterol absorption and intestinal synthesis of cholesterol in the streptozotocin diabetic rat. Twelve diabetic rats were paired with 12 control rats. [14C]-Cholesterol emulsion was administered and the lymph duct was canulated. Lymph was collected for 4h. At sacrifice blood was taken for plasma lipoprotein measurements. Chylomicrons were prepared from the lymph by ultracentrifugation and [14C]-cholesterol content was determined by liquid scintillation counting. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis, and quantified by densitometric scanning. Serum triglyceride and cholesterol were greatly elevated in diabetic compared to control animals (260+/-90 and 9.8+/-8.0 mg/ml vs. 1.0+/-0.4 and 0.6+/-0.3 mg/ml, p < 0.0001 respectively). Lymph chylomicron apo B48 was similar in the two groups. Cholesterol absorption was not significantly different in diabetic compared to control rats but cholesterol synthesis was significantly higher in the diabetic animals (550+/-352 vs. 322+/-113 microg/h p < 0.03). There was a positive correlation between apo B48 and cholesterol absorption (r = 0.70, p < 0.01) in the diabetic rats and control rats (r = 0.71, p < 0.01) but no correlation between apo B48 and cholesterol synthesis in either group. This study demonstrates that cholesterol synthesis was increased in diabetes whereas cholesterol absorption was unaffected suggesting that intestinal cholesterol synthesis made an important contribution to the hypercholesterolaemia seen in the diabetic animals.

The role of microsomal triglyceride transfer protein and dietary cholesterol in chylomicron production in diabetes.

AIMS/HYPOTHESIS: The aim of this study was to examine factors involved in chylomicron production in the streptozotocin diabetic rat, our hypothesis being that the synthesis of the chylomicron is abnormal in diabetes. METHODS: Diabetic rats (n = 20) were paired with control rats (n = 20). Cholesterol emulsion was given by gavage and the lymph duct was cannulated. Lymph was collected for 4 h. Chylomicrons were prepared from the lymph by ultracentrifugation. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis and quantified by densitometric scanning. Intestinal microsomal triglycerol transfer protein mRNA was measured by solution hybridisation nuclease protection, using a rat specific [32P]-labelled cRNA probe. RESULTS: Serum triglyceride and cholesterol were greatly increased in diabetic compared with control animals (258 +/- 77 and 8.9 +/- 6.4 mg/ml vs 1.04 +/- 0.37 and 0.54 +/- 0.03 mg/ml, p < 0.0001). Lymph chylomicron triglyceride and cholesterol were also higher in diabetic rats (29.4 +/- 27.3 and 0.28 +/- 0.3 mg/h vs 16.8 +/- 10.6 and 0.18 +/- 0.09 mg/h, p < 0.05). Lymph chylomicron apo B48 was similar in the two groups. Intestinal microsomal triglycerol transfer protein mRNA was higher in the diabetic rats (12.6 +/- 3.2 vs 3.8 +/- 3.0 amol/microgram RNA, p < 0.0001) and there was a positive correlation between lymph triglyceride and microsomal triglycerol transfer protein mRNA in the whole group (r = 0.65, p < 0.01). CONCLUSION/INTERPRETATION: The study shows that microsomal triglycerol transfer protein mRNA is raised in diabetes without an increase in apolipoprotein B48 in the lymph suggesting that microsomal triglycerol transfer protein regulates chylomicron triglyceride content but not particle number.

Intra-articular lignocaine versus Entonox for reduction of acute anterior shoulder dislocation.

We assessed, in a prospective randomised trial, the relative analgesic effects of Entonox and intra-articular lignocaine (IAL) in patients with acute anterior dislocation of the shoulder. A statistically significant reduction in pain scores was achieved with IAL (7.9 vs 5.2, P < 0.05), but the effect with Entonox was greater (7.8 vs 2.9, P < 0.001). We conclude that Entonox provides better analgesia than IAL in patients with acute anterior shoulder dislocation.

Advanced life support for out-of-hospital cardiac arrest--the changing role of a hospital-based flying squad.

The success of hospital-based flying squads in the management of out-of-hospital cardiac arrest has been well documented, but since the introduction of ambulance paramedics the need for such teams to deal with cardiac arrests has been questioned. We performed a 3-year retrospective study of non-traumatic arrests attended by Medic 1, the flying squad based at the Royal Infirmary of Edinburgh. There were 99 males and 46 females, mean age 57.6 years (range 17-86 years). Seventy-eight (53.9%) patients were pronounced dead at scene, 47 patients (32.4%) were admitted to hospital and 20 (13.7%) survived to hospital discharge. All but two of the survivors had return of spontaneous circulation prior to the arrival of Medic 1. Accident flying squads operating as a secondary response unit to victims of non-traumatic cardiac arrest are unlikely to have a significant effect upon overall survival.

Exercise-induced rhabdomyolysis.

We describe the case of a previously well 55-year-old man who presented to the accident and emergency department with marked swelling of both forearms 6 days after being pulled at speed on a 'fun ride' by a speedboat whilst holding on to a rubber dinghy. Immediately after the event he had marked weakness of both arms lasting 2 days and this was followed by swelling of his forearms. The patient had also noticed a darkening of his urine during this period. On examination there was marked pitting oedema of both forearms. Neurovascular examination of both arms was normal. Laboratory investigations revealed a grossly elevated serum creatinine kinase at 4969 IU/l, with normal urea and electrolyte levels. Urine dipstick testing was also normal at the time of presentation. The patient was discharged home and made an uneventful recovery. We describe the pathophysiology of exercise-induced rhabdomyolysis and discuss its clinical presentation and management.

Edinburgh's Hogmanay celebrations: beyond a major disaster.

OBJECTIVE: To assess the impact of Edinburgh's Hogmanay celebrations on the city's accident and emergency (A&E) service. METHODS: Retrospective analysis. RESULTS: A crowd estimated at more than 350,000 attended the celebrations. During the three day period between 00.01 h on 31 December and 23.59 h on 2 January, 1151 new patients presented to the A&E department and of these half arrived in the first 24 hours. Thirty six patients required emergency resuscitation and eight died in the department during the study period. CONCLUSIONS: The absolute number of patients presenting during the study period greatly exceeded most of the "major disasters" in contemporary UK experience. No deaths were directly attributable to the event, but the spectrum of patient pathologies, their severity and presentation is analogous to several recent major incidents. It is doubtful whether the Hogmanay celebrations are safe.

An apparently new virus (family Paramyxoviridae) infectious for pigs, humans, and fruit bats.

We isolated an apparently new virus in the family Paramyxoviridae from stillborn piglets with deformities at a piggery in New South Wales, Australia. In 1997, the pregnancy rate and litter size at the piggery decreased markedly, while the proportion of mummified fetuses increased. We found serologic evidence of infection in pigs at the affected piggery and two associated piggeries, in humans exposed to infected pigs, and in fruit bats. Menangle virus is proposed as a common name for this agent, should further studies confirm that it is a newly recognized virus.

Heparan sulfate proteoglycan-mediated uptake of apolipoprotein E-triglyceride-rich lipoprotein particles: a major pathway at physiological particle concentrations.

We explored potential mechanisms of non-low-density lipoprotein (LDL) receptor-mediated uptake of triglyceride-rich particles (TGRP) in the presence of apolipoprotein E (apo E). Human fibroblasts were incubated with model intermediate-density lipoprotein- (IDL-) sized TGRP (10-1000 microg of neutral lipid/mL) containing apo E. The extent of receptor-mediated uptake of TGRP was assessed with (a) an anti-apo E monoclonal antibody, which blocks receptor interaction; (b) incubation with heparin; (c) normal vs LDL receptor-negative fibroblasts; and (d) receptor-associated protein (RAP) to determine the potential contribution of LDL receptor-related protein (LRP). Cell surface heparan sulfate proteoglycan- (HSPG-) mediated uptake was examined with or without the addition of heparinase and heparitinase to cell incubation mixtures. At low particle concentrations (250 microg of neutral lipid/mL), most (>/=60%) particle uptake and internalization was via HSPG-mediated pathways. This HSPG pathway did not involve classical lipoprotein receptors, such as LRP or the LDL receptor. These data suggest that in peripheral tissues, such as the arterial wall, apo E may act in TGRP as a ligand for uptake not only via the LDL receptor and LRP pathways but also via HSPG pathways that are receptor-independent. Thus, at physiologic particle concentrations apo E-TGRP can be bound and internalized in certain cells by relatively low affinity but high capacity HSPG-mediated pathways.

Circulating anti-(xanthine oxidoreductase) antibodies in healthy human adults.

Levels of free anti-(xanthine oxidoreductase) (XOR) antibodies in the serum of normal healthy human subjects were determined, using both human and bovine enzyme as antigen, in an enzyme-linked immunosorbent assay (ELISA). Levels of IgM class anti-(human XOR) antibodies were found to be particularly high (mean values representing approximately 3% of total IgM) and to be significantly higher than levels of IgM anti-(bovine XOR) antibodies, indicating that endogenous XOR, rather than ingested bovine milk XOR, is the immunogen. IgM anti-XOR antibody levels were significantly higher in women under 50 years than in age-matched men, or in older women. Levels of IgG class anti-XOR antibodies were much lower and showed no correlation with gender or age. Affinity-purified anti-(human XOR) antibodies only partially inhibited enzymic activities of XOR. The majority of both IgM and IgG anti-(human XOR) antibodies in serum occurred as immune complexes, suggesting that the specific antibodies have a protective role in removing potentially damaging XOR from the circulation.

Comparison of intra-articular lignocaine and a suprascapular nerve block for acute anterior shoulder dislocation.

We compared the analgesic effects of a suprascapular nerve block with intra-articular local anaesthetic in 20 patients presenting with acute anterior glenohumeral dislocations. The intra-articular local anaesthetic technique was a simpler procedure which provided significantly more analgesia for patients.