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.

[MR thermometry for laser-induced thermotherapy at 1.5 Tesla]. / MR-Thermometrie bei 1,5 Tesla zur thermischen Ablation mittels laserinduzierter Thermotherapie.

PURPOSE: Evaluation of thermometry with fast MR sequences for laser-induced interstitial laser therapy (LITT) and verification of the thermometric results with a fiber-optic thermometer. METHOD AND MATERIALS: In vitro experiments were conducted using an agarose gel mixture and pig liver lobes. MR-guided LITT was performed using a laser power between 3 and 15 watts. Thermometry was performed using longitudinal relaxation time T1 and proton resonance frequency shift (PRF) methods under acquisition of amplitude and phase shift images. PRF was measured with a fast spoiled GRE sequence. Four different sequences were used for T1 thermometry: gradient echo (GE), TrueFISP (TRUFI), Saturation Recovery Turbo-FLASH (SRTF) and Inversion Recovery Turbo-FLASH (IRTF) sequences. The temperature was controlled using a fiber-optic Luxtron device and correlated with the MR temperature. The range of applied and monitored temperatures exceeded 80 degrees Celsius. RESULTS: The temperature dependence showed a good linear relationship up to 60 degrees Celsius. Calibration experiments for the T1 method delivered coefficients of determination from 0.977 to 0.997 for agarose and from 0.958 to 0.995 for the pig liver samples. The IRTF sequence had the highest temperature sensitivity (agarose 0.99, liver 1.19). During LITT the TRUE-FISP sequence exhibited a strong nonlinear relationship. R (2) of this sequence was 0.809 in the agarose experiments. The average temperature errors when heated up to 80 degrees Celsius were 3.86-11.38 degrees Celsius for Agarose gel and 5.7-12.16 degrees Celsius for the liver tissue. SRTF and IRTF sequences exhibited the most linear relationship with temperature but were more dependent on tissue differences. CONCLUSION: The accuracy of the temperature measurement is sufficient for controlling the coagulation area of the LITT. PRF is the method of choice since it shows the best linear correlation with fiber-optic temperature. If only T1 sequences are concerned, the FLASH sequence is preferred. It is the most robust, though not the most accurate, T1 sequence.

Body composition at the bedside.

OBJECTIVE: To evaluate the use of an inexpensive hand-held bioelectric impedance analysis machine which measures lean body mass, by technical comparisons against standard instruments and techniques (an in-house bioelectric impedance machine and dual energy X-ray absorptiometry), and by performing body composition analyses in groups of potentially malnourished patients. DESIGN: Prospective simultaneous comparison of measurements made by the hand-held and in-house bioelectric analysis machines and dual energy x-ray absorptiometry. SETTING: Medical Physics Department and Gastrointestinal Unit in a university teaching hospital. SUBJECTS/METHODS: One hundred and sixty subjects were recruited into the study. Data from 58 adolescent and 14 adult volunteers and from 42 adult patients were used for technical comparisons (n = 114). Body composition information was evaluated (n = 102) for 60 adult volunteers and 42 patients (17 with eating disorders, 7 with chronic alcoholic pancreatitis and 18 with inflammatory bowel disease). OUTCOME MEASURES: Estimation of bias, limits of agreement and correlations on data from the three machines. Relationships between percentage body mass as lean, absolute weights and body mass index, in the adult subjects. RESULTS: Both resistance and calculated impedance measured by the hand-held machine significantly correlated with the impedance measured by the in-house machine (r = 0.996; P < 0.0001). An estimation of the level of agreement in percentage lean measurement between dual energy x-ray absorptiometry and hand-held bioelectrical impedance analysis machine by the Bland and Altman method showed a bias of -0.07% and satisfactory limits of agreement from -7.97% to 7.76%. Body mass index was similar in the groups of healthy men and women, but proportion of weight as lean was significantly higher in men than women. In underweight patients with eating disorders, the ratio of lean to fat varied widely; in inflammatory bowel disease patients, proportions of lean and fat were similar to controls; however patients with alcoholic pancreatitis had values for body mass index similar to controls, but had significantly lower proportion of their body weight as lean (P < 0.05). CONCLUSION: In non-obese and thin adults, an accurate two-compartment (lean, fat) measurement of body composition can be made in 10 min by using an inexpensive, hand-held, bioelectric impedance analysis machine.

Anti-inflammatory effects of enteral diet components on Crohn's disease-affected tissues in vitro.

BACKGROUND: The mechanism of action of elemental diet in Crohn's disease treatment, is unknown. Alteration of bacterial flora, low antigenicity, low fat content and improvement of nutritional status are postulated to play a role in the anti-inflammatory effect of elemental diet. AIM: To determine whether elemental diet or its modifications has a direct anti-inflammatory effect on colonic tissue biopsies in vitro. PATIENTS AND METHODS: Colonic or ileal biopsies from 39 patients with inflammatory bowel disease and control patients were incubated for 24 hours with enteral diets in which nitrogen sources were amino acids as in elemental diet, casein or whey. Tissues were incubated with elemental diet, casein or whey, at dilutions of 1:5, 1:10 or 1:20 in Waymouth's complete medium; a medium control was also included. Tissue viability was assessed by bromodeoxyuridine uptake. Interleukin-1beta, interleukin-1 receptor antagonist and interleukin-10 concentrations in supernatants were measured by immunoassay (enzyme-linked immunosorbent assay). RESULTS: Incubation of tissues from Crohn's disease with elemental diet resulted in an increase in the ratio of interleukin-1 receptor antagonist/interleukin-1beta vs control statistically significant at 1:10 (89.6+/-17 vs 45.7+/-9. 1, p<0.05). Incubation of Crohn's tissue with casein resulted in a significant increase of interleukin-1 receptor antagonist/interleukin-1beta ratio at dilutions 1:20, 1:10 and 1:5 (101.8+/-22.0, p=0.05, 142.8+/-24.6, p<0.05; 109.7+/-25.0, p=0.05). In ulcerative colitis tissue and non-inflamed non-inflammatory bowel disease control tissue, no significant increase in interleukin 1 receptor antagonist/interleukin-1beta ratio was seen after incubation with elemental diet, casein and whey. CONCLUSION: Elemental diet incubation increases anti-inflammatory:proinflammatory cytokine ratio in Crohn's disease and this anti-inflammatory effect is not specifically due to amino acid composition, as diets containing casein have similar anti-inflammatory effects.

A 3D electrical impedance tomography (EIT) system for breast cancer detection.

A medical device which allows imaging of the distribution of conductivity in 3D in regions below the skin surface has been developed and tested. Its purpose is to enable early detection and preliminary diagnosis of breast tumours. Design of the measuring system and software are described. Results of clinical evaluation of the system are presented. EIT images of healthy and cancerous breasts are presented and discussed. The system is able to visualize various states of the breast and it may be possible to apply it to breast cancer detection.

The role of Human Factors in system development.

The application of Human Factors or ergonomics principles to American system development occurs in a highly unstructured, problem-solving environment in which inputs compete with each other for acceptance. Factors determining whether human engineering inputs will be accepted include: the specification (or lack thereof) of personnel performance requirements; the advantages supplied by the human engineering recommendation; the costs involved in implementing it; the funding supplied by the customer for the new system; and his oversight of human engineering efforts. Human Factors efforts are required in at least five of the six major phases of system development: System Planning; Predesign; Detail Design; Production; Test and Evaluation; and Operations. Each phase introduces behavioural questions that must be answered if the system is to be designed properly. Each question demands specific techniques and skills of the human engineer.

Human factors problems and solutions.

The human engineer faces both organisational and technical difficulties in making his contribution to system development. Since engineering designers and managers are relatively indifferent to behavioural problems, they are inclined to ignore human engineering inputs. In addition, the available techniques for answering complex behavioural questions arising during development are not adequate. A continuing process of indoctrination may ultimately change engineering attitudes but this process will be very slow. It seems more effective to concentrate on developing the necessary human engineering techniques to answer development questions and thereby demonstrate the worth of Human Factors in system development. This process will also be slow but at least it will be under the control of Human Factors specialists. Eighteen areas of research to develop the necessary techniques are described.

The present and future of human factors.

In view of the problems facing human factors specialists, how do they feel about the present status of their profession and its future prospects? A small number of highly qualified practitioners were asked their opinions about various questions which have been discussed in two previous articles in this series. In a 1979 survey they agreed that designers rarely solicit human engineering assistance and resist human engineering inputs; that the behavioural research reported in the literature is of relatively little value in system development work; that government does not monitor human engineering in system development very effectively. In a survey performed for this article, specialists were generally optimistic about the future of their discipline but concerned about government funding and job support under the Reagan administration; felt that engineering and public acceptance of human factors is increasing slowly; were ambivalent about any significant improvement in methodology; and considered that the scope of human factors work would expand in the future. The need for human factors should increase in the future and the future looks reasonably promising if specialists learn to deal with a rapidly changing technological environment.

Kinetics of hydroxyethyl starch in horses.

In a controlled study, the distribution and elimination kinetics of hydroxyethyl starch as well as clinically relevant parameters were determined in horses. The half-life of the first phase was 5.59 hours, that of the second phase 122.22 hours. During the first phase, hydroxyethyl starch persisted almost exclusively intravascularly. The results of this study are largely in agreement with those in human beings. Thus, routes of elimination, duration of plasma-expanding action, distribution volume and redistribution kinetics in horses and human beings are very similar. However, the elimination kinetics of the second phase and the behavior of serum amylase appear to be equine-specific. Coagulation is barley influenced by the administration of hydroxyethyl starch. The results of this study confirm that hydroxyethyl starch is very suitable for use as a plasma-expander in horses.

[Experiences with the QBC-V hematology system at the veterinary hospitals of Zurich and Bern]. / Erfahrungen mit dem QBC-V-Hämatologiesystem an den Tierspitälern Zürich und Bern.

The QBC V hematology system was tested with respect to its application in veterinary medicine. PCV's and counts of total leukocytes, granulocytes, lympho/monocytes and platelets collected from 435 horses, dogs and cats were determined and compared with conventionally measured values. Precision and accuracy were found to be good for the majority of parameters. In the authors' opinion the QBC V hematology system is well suited for use in veterinary practice.

[Preliminary experiences with the treatment of shock in horses with a plasma expander from a starch base]. / Erste Erfahrungen bei der Schockbehandlung des Pferdes Mit Einem Plasmaexpander auf Stärkebasis.

HAES Steril 10% is a colloidal plasma expander rarely used in veterinary medicine. In this study HAES was used in clinical cases for the treatment of shock and in a comparative hypervolemic hemodilution study (HAES versus lactated Ringer's solution) using two experimental horses. Injection of a HAES volume equivalent to 10% of estimated blood volume resulted in a highly significant drop in PCV and in a significant drop in total protein concentration. Half live of HAES was approximately two hours. No incompatibility reactions were observed. In man HAES improves microcirculation. Studies in progress may confirm a similar effect in the equine.

Chronic periodontal disease is associated with single-nucleotide polymorphisms of the human TLR-4 gene.

Periodontitis is an inflammatory disease affecting the connective tissue surrounding the teeth leading to tooth loss. Pathogens associated with periodontitis interact with Toll-like receptors (TLRs) to induce cytokines causing and aggravating disease. We screened 197 individuals suffering from generalized periodontitis for the presence of Asp299Gly and Thr399Ile of TLR-4 as well as Arg753Gln of TLR-2 in comparison to matched controls. Single-nucleotide polymorphisms (SNPs) of TLR-4 were elevated among patients (odd's ratio 3.650, 95% CI 1.573-8.467, P < or = 0.0001), while no difference was observed for TLR-2. TLR-4 SNPs were correlated with chronic periodontitis (odd's ratio 5.562, 95% CI 2.199-14.04, P < or = 0.0001), but not with aggressive periodontitis. This observation was confirmed employing a group of periodontally healthy probands over 60 years of age. These data demonstrate that genetic variants of TLR-4 may act as risk factors for the development of generalized chronic periodontitis in humans.

Modification of enteral diets in inflammatory bowel disease.

The provision of food is thought to promote the maintenance of gut integrity. Nutrients are able to elicit and affect both systemic and mucosal immune responses. Enteral diet therapy has long been known to be efficacious in inflammatory bowel disease (IBD), particularly in childhood Crohn's disease. However, the mechanisms of action of these diets are not clear. Nutritional repletion, direct effects on the gut mucosa or decreased intestinal permeability have all been postulated as being important in nutritional therapy. There is some evidence that the enteral diet has a direct effect on the gut mucosa by reducing cytokine production and the accompanying inflammation, thus leading to decreased intestinal permeability. Modifications of enteral diet composition have been evaluated in many studies. Such modifications include fat and/or protein content and the addition of bioactive peptides. The fatty acid composition of the enteral diet seems to have a much greater impact on its efficacy than modification of the N source. As specific fatty acids are precursors of inflammatory mediators derived from arachidonic acid, the reduction in these components may be beneficial in nutritional therapy for IBD. Addition of bioactive peptides to enteral diet formulas may also have a role; such peptides may have specific growth factor or anti-inflammatory actions. There is still much work to be done to define disease-specific enteral diet formulas that are effective as therapies for both Crohn's disease and ulcerative colitis.

The tubular loop fermentor: oxygen transfer, growth kinetics, and design.

Oxygen transfer measurements using a dynamic method and evaluated with an appropriate mathematical model have been made on a tubular loop bioreactor, Correlations of the type used in tank systmes are used to describe the influence of power and aeration rate on the mass transfer coefficient. Yeast cultures grown on hydrocarbon and glucose substrates show growth characteristics similar to conventional tank results. Model considerations for large-scale tubular fermentors allow for the prediction of the steady-state oxygen profiles and maximum reactor length. Combination with two-phases flow and oxygen transfer correlations yields a design procedure for commercial scale tubular loop fermentors.

Interobserver variability of sonographically determined second-trimester nuchal skinfold thickness measurements.

Twenty physicians experienced in fetal sonographic evaluation obtained fetal nuchal skinfold thickness measurements in each of five pregnant women between 16 and 18 weeks' gestation. A random effects analysis of variance model was used to explore the sources of variation in the set of measurements, to determine the interobserver variability of sonographically measured second-trimester nuchal skinfold thickness. It was possible to obtain 96 measurements. Four measurements (all in the same patient) were deemed unobtainable due to fetal position. All recorded measurements were between 1.7 and 4.5 mm. The means (and ranges) for the five patients were 2.7 (1.7-3.6), 2.9 (2.0-4.5), 2.7 (2.0-4.0), 3.3 (2.2-4.0), and 2.7 (1.8-4.0) mm. The standard deviation for interobserver variability, caused by the combined effect of physician and machine imprecision, was 0.56 mm and the overall coefficient of variation was 19.8%. Interpatient differences were statistically significant (p = 0.004). Interphysician differences were not (p = 0.11). We conclude that experienced physician sonographers using high-resolution ultrasound equipment are able to obtain second-trimester nuchal skinfold thickness measurements within 1.1 mm of the estimated true value with 95% probability.

[Experiences with long-term intravenous therapy using teflon catheters in 80 horses]. / Erfahrungen mit der langdauernden intravenösen Therapie mittels Teflonkathetern bei 80 Pferden.

In a retrospective study the tolerance to Teflon coated catheters in long-term intravenous medication was evaluated in 80 horses. Catheters were inserted into the jugular vein and remained there for 3 to 30 days (average 8.6 days). Catheters were flushed using an heparinized solution after each medication administration. The site of catheter placement was evaluated daily for swelling, pain and venous distensibility respectively. Swelling at the site of insertion was noted in 10 horses, a small subcutaneous abscess formation was identified in one horse. Fourteen sonographic evaluations were performed on 10 horses, demonstrating perivascular changes in four. Thrombus formation did not occur. In all horses the catheter could be identified floating freely within the vascular lumen. Catheter failure occurred in nearly a third of all cases either as a result of mechanical failure or of pull-out by the horse. After removal of the catheter no adverse side effects attributable to the mode of medication were noted in any of the horses. In conclusion, intravenous medication using Teflon-coated catheters is a suitable alternative to other modes of administration.

Analytical profile of metaclazepam.

Physical and physicochemical properties of 7-bromo-5-(2'-chlorophenyl)-2, 3-dihydro-2-(methoxy-methyl)-1-methyl-1H-1,3-benzodiazepine (metaclazepam, Talis), a new anxiolytic 2-methoxymethyl-1,4-benzodiazepine derivative, are reported. Furthermore the analytical methods for quantitative determinations of metaclazepam are described.