Magnetic assessment and modelling of the Aramis undulator beamline.

Within the SwissFEL project at the Paul Scherrer Institute (PSI), the hard X-ray line (Aramis) has been equipped with short-period in-vacuum undulators, known as the U15 series. The undulator design has been developed within the institute itself, while the prototyping and the series production have been implemented through a close collaboration with a Swiss industrial partner, Max Daetwyler AG, and several subcontractors. The magnetic measurement system has been built at PSI, together with all the data analysis tools. The Hall probe has been designed for PSI by the Swiss company SENIS. In this paper the general concepts of both the mechanical and the magnetic properties of the U15 series of undulators are presented. A description of the magnetic measurement equipment is given and the results of the magnetic measurement campaign are reported. Lastly, the data reduction methods and the associated models are presented and their actual implementation in the control system is detailed.

Transverse gradient in Apple-type undulators.

Apple-type undulators are globally recognized as the most flexible devices for the production of variable polarized light in the soft X-ray regime, both at synchrotron and free-electron laser facilities. Recently, the implementation of transverse gradient undulators has been proposed to enhance the performance of new generation light sources. In this paper it is demonstrated that Apple undulators do not only generate linear and elliptical polarized light but also variable transverse gradient under certain conditions. A general theoretical framework is introduced to evaluate the K-value and its transverse gradient for an Apple undulator, and formulas for all regular operational modes and different Apple types (including the most recent Delta type and Apple X) are calculated and critically discussed.

The Materials Science beamline upgrade at the Swiss Light Source.

The Materials Science beamline at the Swiss Light Source has been operational since 2001. In late 2010, the original wiggler source was replaced with a novel insertion device, which allows unprecedented access to high photon energies from an undulator installed in a medium-energy storage ring. In order to best exploit the increased brilliance of this new source, the entire front-end and optics had to be redesigned. In this work, the upgrade of the beamline is described in detail. The tone is didactic, from which it is hoped the reader can adapt the concepts and ideas to his or her needs.

Performance of the LHCb RICH detector at the LHC.

The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (π, K, p) is achieved.

Clinical pharmacokinetics of tacrolimus in heart transplant recipients.

We report pharmacokinetic data on tacrolimus in 14 heart transplant patients (2 women, 12 men). The median age and the median body weight were 55.5 years (range, 23-61 years) and 67.0 kg (55-79 kg), respectively. All patients were maintained on a triple-drug protocol (tacrolimus, azathioprine, and prednisone), with a 7-day antithymocyte globuline induction. The first tacrolimus dose, administered orally 1 to 5 days posttransplant, ranged from 0.03 to 0.4 mg/kg (median = 0.052 mg/kg). The maintenance dose ranged from 0.03 to 0.13 mg/kg/day (administered in two equal doses) to achieve blood levels of 5 of 20 ng/ml, as determined by a microparticle enzyme immunoassay (MEIA). Whole blood samples were drawn just before, at 0.5 hour, and at 1, 2, 3, 4, 6, 8, 10, and 12 hours after the administration of the first dose; trough levels were measured thereafter. The mean oral clearance (CL/F) and apparent volume of distribution (Vd/F) averaged 0.21+/-0.08 L/hour/kg and 2.4+/-0.8 L/kg while the half-life averaged 8.7+/-3.5 hours. Tacrolimus accumulation index during chronic therapy (Rac = Cmin(steady state)/Cmin(first dose) normalized to the same dose) averaged 1.3. Eighty-eight percent of the trough blood levels measured in our patients were within 5 and 20 ng/ml. The incidence of rejection in the study population was extremely low: a prevalence of grade 2 rejection or more, of 0.4+/-0.8 episodes/ patient was observed after a follow-up period of 8.8+/-2.2 months. Only one patient experienced severe renal toxicity, probably because of his preoperative precarious hemodynamic status. Pharmacokinetic data suggest that maintenance tacrolimus daily dose should be equal to 0.1 mg/kg/day to obtain trough blood concentrations of approximately 10 ng/ml. Inter- and intra-patient variability of tacrolimus blood concentration should be expected and justify careful monitoring.

[Seizures associated with acute subarachnoid hemorrhage. Emergency diagnosis and treatment]. / Crisi comiziali nell'ESA in fase acuta. Diagnosi e trattamento urgente.

Seizures and convulsive status in patients with subarachnoid haemorrhage are an emergency. They are not only known to increase cerebral metabolic rate but also cerebral blood flow and intracranial pressure and rebleeding can occur in patients with an unclipped aneurysm. The goal of therapy is to stop the seizures minimizing the risk of secondary brain damage (hypoxia, hypotension, hypercarbia, hyperthermia). Several active drugs are available for treating seizures, it is important to identify the cause, prompt administration, monitoring the patients and choosing the one with less side effects.

Complications of internal jugular vein retrograde catheterization.

We report on the incidence of complications of 172 internal jugular vein retrograde catheterizations (IJVRCs) performed on 126 patients. Standard cannulation and X-ray control of the catheter tip placement were performed. Difficulties encountered during the manouvre were registered. Patients with a jugular catheter in place for more than one day had neck echography on catheter removal and one week later. Carotid artery puncture occurred in 20 (12%) cases and lymphatic vessel puncture in one. In 13 (8%) cases IJVRC failed due to difficulties in advancing the guide. X-ray films documented catheter misplacement in 39 (23%) cases: loop into the internal jugular vein in 11 (6%); paravertebral venous plexus cannulated in one; other extracranial jugular afferent cannulated in 4 (2%); catheter tip into the jugular lumen in 10 (6%); catheter tip beyond the jugular bulb in 13 (8%). First neck echography documented: one perivascular hematoma (absent one week later); 3 (4%) jugular vein thrombosis (2 asymptomatic and absent one week later; one symptomatic and still evident one week later). Positive neck echography was not associated with difficulties, length of catheterization, diameter of the catheter. IJVRC is a simple and safe procedure with a low incidence of serious complications.

7.5% hypertonic saline versus 20% mannitol during elective neurosurgical supratentorial procedures.

This prospective randomized clinical study was designed to compare the effects of equal volumes of 7.5% hypertonic saline solution (HS) or 20% mannitol (M) on brain bulk and lumbar cerebrospinal fluid pressure (CSFP) during elective neurosurgical procedures (aneurysm, arteriovenous malformation, or tumor). After informed consent, 50 American Society of Anesthesiologists physical Status I (ASA I) patients were randomly assigned to M (n = 25) or HS (n = 25) groups. Anesthesia protocol was identical for both, and variables monitored included mean arterial blood pressure (MAP), heart rate (HR), central venous pressure (CVP), CSF pressure (CSFP), arterial blood gases (PaCO2 30-35 mm Hg), serum sodium, potassium, and osmolality, and diuresis. The study period started before hypertonic solution administration (T0) and ended at the opening of the dura mater or 60 min after T0. Data were assessed with repeated measures analysis of variance and Student t test with Bonferroni correction (p < or = 0.05). MAP and CVP were the same in the two groups. After treatment, osmolality increased, and the increase at T15 was higher in HS-treated patients [316.6 +/- 9.3 vs. 304.0 +/- 12.0 (SD) mOsmol/kg; p < 0.001]. Sodium decreased after M and increased after HS. During the study, brain bulk was always considered satisfactory. CSFP was not different between M and HS groups and significantly decreased overtime (p = 0.0056) with no difference between treatments. The results of the present study demonstrate that hypertonic saline is as effective as mannitol in reducing the brain bulk and the CSFP during elective neurosurgical procedures under general anesthesia.

Intensive care management of patients with subarachnoid hemorrhage at san raffaele hospital, milan.

SUMMARY: Intensive care of patients with SAH is targeted to recognize and treat the leading cause of death and disability. Hemorrhage, vasospasm, rebleeding, intracranial hypertension can produce ischaemia because the ratio between metabolism (CMR0 (2) ) and cerebral blood flow (CBP) is not coupled. Neuro-ICU bedside monitoring provides information on the intracranial dynamics. Aggressive treatment attempts to avoid ischaemia but needs a clipped or thrombosed (via endovascular approach) aneurysm. The authors propose treatment to improve CBP and reduce CMRO (2) : hypervolaemia, hemodilution, hypertension, ICP reduction, normocapnia, mannitol infusion, normothermia or mild hypothermia and sedation with intravenous anaesthetics. Medical complications such as hypovolemia, infections, pulmonary oedema, gastrointestinal bleeding need to be recognized early and treated.

[Pharmacokinetics of ceftriaxone in the first three month of life]. / Farmacocinetica del ceftriaxone nei primi tre mesi di vita.

The purpose of the study was to define more precisely ceftriaxone kinetic variations in neonates and infants during the first three months of life. Ceftriaxone pharmacokinetics were studied in 14 newborns and infants with gestational age ranging from 31 to 42 weeks and younger than three months of postnatal age. Ceftriaxone was administered as an intravenous bolus injection over 15 min at a dose of 50 mg/Kg every 24 hours, for a period of 7 to 28 days according to the bacterial diseases. 13 patients had normal renal function and one had a chronic renal insufficiency. Plasma and urine concentrations were measured by a specific HPLC assay. The mean plasma concentration was 180.7 +/- 19.9 ug/ml (mean +/- SD) 30 min after the beginning of the infusion. After 24 h the plasma value was 29.9 +/- 10.0 ug/ml. The mean elimination half-life (t1/2) was 19.9 h, the total clearance (CL) of the drug was 0.38 ml/min/Kg and the volume of distribution (Vd) was 0.32 l/Kg. About 52% of the administered dose was excreted unchanged in urine. In the patient with renal insufficiency we observed t1/2 = 38.9 h and CL = 0.10 ml/min/Kg. Only a slight accumulation of the drug (from 180.7 +/- 19.9 ug/ml to 223 +/- 15.5 ug/ml) was observed during multiple dosing. The volume of distribution and the plasma half-life were significantly correlated (negative correlation) to the postnatal age. There was no correlation between clearance and postnatal age. No side effects were observed in newborns and infants after administration of ceftriaxone.

Cefotaxime therapy of lower respiratory tract infections in intensive-care patients.

Cefotaxime is one of two third-generation cephalosporins (the other being ceftriaxone) that undergo significant metabolism and is the only third-generation cephalosporin for which an active metabolite has been identified. Cefotaxime was administered intravenously in doses of 6 g per day to 20 patients with serious infections of the lower respiratory tract due to organisms susceptible to cefotaxime (isolates of Enterobacteriaceae and of Pseudomonas aeruginosa). It was administered with gentamicin in some high-risk patients. Cefotaxime resulted in mean peak concentrations of 32 mu/ml (cv% = 53) and of 29.5 micrograms/ml (cv% = 65) respectively after the first and after the last dose of a regimen of 2 g every 8 hours. The half-life value averaged 1.8 h and 6.4 h for cefotaxime and its desacetyl metabolite respectively. The average value of the metabolite at the end of short infusion was 11.5 micrograms/ml (cv% = 31) after the initial dose and 15.5 micrograms/ml (cv% = 37) after the last administered dose. Overall results were 75% patients cured or improved; 83% of the patients with nosocomial pulmonary infections due to Enterobacteriaceae were cured; 50% of the patients with Pseudomonas aeruginosa infections were cured and 25% improved despite the pathogen not being eradicated. No serious toxicity was observed.

Ceftazidime in the treatment of Pseudomonas infections in intensive-care patients.

The present study was designed to define the clinical activity and pharmacokinetics of ceftazidime in Pseudomonas sp. infections. The intensive care patients included in this study were hospitalized for at least 2 weeks and have frequently received antibiotic treatment which contributed with poor host resistance to the infections with highly resistant Pseudomonas strains. Sixteen adult patients entered the study. Their age ranged from 18 to 70 years. Ceftazidime was administered in a dose of 2 g three times daily by a constant infusion over 20-30 min. Frequent clinical assessment multiple cultures and determination of renal, hepatic and bacteriological functions were performed. Bacterial cultures were obtained prior to the beginning of therapy and every 2-3 days thereafter with a follow-up period of about 1-2 weeks. Pharmacokinetics in the blood were performed. Measurements of ceftazidime were made by using HPLC. Mean peak serum concentration of ceftazidime was 58.5 micrograms/ml after administration of 2.0 g of ceftazidime and eight hours after dosing the mean plasma concentration was about 5 micrograms/ml. No accumulation of ceftazidime could be observed during the treatment period. Mean plasma half-life was 2.1 hours at the beginning and 2.2 hours at the end of therapy. The mean apparent volume distribution was 0.35 l/kg. No severe adverse effects were reported throughout the study. Ceftazidime may be effectively used as single antiinfective agent in various conditions and higher plasma concentrations are an important predictor of bacteriological and clinical response in pulmonary infections caused by Pseudomonas species.