First results in coherent harmonic generation using the undulator at the MAX-lab electron storage ring

An experiment in coherent harmonic generation has been performed at the MAX-lab electron storage ring in Lund. Coherent photons were produced in the third harmonic of a Nd:YAG laser focused on the electron beam in a permanent magnet undulator. The number of coherent photons, the linewidth, the current dependence and other parameters have been measured.     

Preoperative gastric emptying. Effects of anxiety and oral carbohydrate administration

BACKGROUND: Overnight fasting is routine before elective surgery. This may not be the optimal way to prepare for surgical stress, however, because intravenous carbohydrate supplementation instead of fasting has recently been shown to reduce postoperative insulin resistance. In the current study, gastric emptying of a carbohydrate-rich drink was investigated before elective surgery and in a control situation. METHODS: Twelve patients scheduled for elective surgery were randomly given 400 mL of either a carbohydrate-rich drink (285 mOsm/kg, 12.0% carbohydrates, n = 6) or water 4 hours before being anesthetized. Gastric emptying was measured (gamma camera, 99Tcm). Each patient repeated the protocol postoperatively as a control. All values were presented as the mean +/- SEM by means of a nonparametric statistical evaluation. RESULTS: Despite the increased anxiety experienced by patients before surgery (p < 0.005), gastric emptying did not differ between the experimental and control situations. Initially, water emptied more rapidly than carbohydrate. However, after 90 minutes, the stomach was emptied regardless of the solution administered (3.2 +/- 1.1% [mean +/- SEM] remaining in the stomach in the carbohydrate group versus 2.3 +/- 1.2% remaining in the stomach in the water group). CONCLUSIONS: Preoperative anxiety does not prolong gastric emptying. The stomach had been emptied 90 minutes after ingestion of both the carbohydrate-rick drink and water, thereby indicating the possibility of allowing an intake of iso-osmolar carbohydrate-rich fluids before surgery.     

Phase behaviour of some aqueous systems involving monoglycerides,cholesterol and bile acids

A report is given on the phase behaviour of various monoglyceride-water systems relevant in foods. Interactions with cholesterol and bile acid salts as well as small water-soluble molecules as a third component are described. The cubic phase occurring in systems of monoglycerides of sunflower oil can solubilise bile salts and coexist with bile acid salt micelles, which might result in a reduction in fat absorption in the intestine. Also the observed solubilisation of cholesterol in the cubic phase should be expected to reduce cholesterol uptake when this phase is formed. Evidence is given indicating that monocaproin might be of technical interest in order to solubilise hydrophobic proteins and the interactions between aqueous monocaproin phases and soy-bean oil and sodium chloride were examined in this context.     

Epidemiologic significance of detecting shigellae during examination of a healthy population

The authors present the results of examination of the healthy population for shigellae carrier state. The efficacy of detection of shigellae depending on the season of the year and indications to the examination was compared. Analysis of the data obtained indicated that any examination for shigellae during the extraepidemic period was inexpedient. This conclusion was confirmed by the results of selective examination with the use of bacteriological and serological methods.     

Forklift safety, traffic engineering and intelligent transport systems: a case study

This paper details a forklift safety demonstration project undertaken at two manufacturing sites in Victoria, Australia. The purpose of the work was both to help improve safety at the two sites, and, more broadly, to develop, help implement and evaluate a series of human-centred design interventions involving vehicles and pedestrian workers. The ‘before’ and ‘after’ case study presented here summarises the background to the research and introduces the test sites. Thereafter, it describes the overall nature of the safety interventions proposed and introduces the methods developed to assess safety. For the traffic engineering interventions, positive safety results were found in terms of reductions in the number of potentially hazardous interactions involving forklifts. Similarly, for the vehicle interventions, the research found that forklift drivers and managers considered the newly developed and installed Intelligent Transport Systems to be broadly acceptable in operational conditions, and the systems’ intended safety benefits were well understood. The results are discussed and conclusions are drawn regarding human factors aspects of forklift safety.     

Attraction of the Larval Predator Elater ferrugineus to the Sex Pheromone of Its Prey, Osmoderma eremita, and Its Implication for Conservation Biology

Elater ferrugineus is a threatened click beetle inhabiting old hollow trees. Its larvae consume larvae of other saproxylic insects including the threatened scarab beetle Osmoderma eremita. Recently, (R)-(+)-gamma-decalactone was identified as a male-produced sex pheromone of O. eremita. Here we present evidence that E. ferrugineus adults use this odor as a kairomone for location of their prey. In field trapping experiments, significantly more trapping events of E. ferrugineus beetles were observed in Lindgren funnel traps baited with (R)-(+)-gamma-decalactone than in control traps (20 vs. 1, respectively). Analyses of headspace collections from E. ferrugineus beetles indicate that the predator itself does not produce the substance. Both sexes were attracted to the prey pheromone. suggesting that E. ferrugineus males use the odor as an indirect cue for location of mates or of the tree hollows, which make up their habitat. When compared to pitfall traps, the Lindgren system was significantly more effective in trapping E. ferragineus, and no difference could be established for O. eremita, showing the high potential to use odor-based systems to catch both species. We suggest that (R)-(+)-gamma-decalactone could be used as a master signal in monitoring programs for these vulnerable beetle species. which are both regarded as indicators of the associated insect fauna of the threatened habitat of old hollow trees.     

Tobacco smoking increases dramatically air concentrations of endotoxin

We used a mass spectrometry-based assay for identifying the endotoxin (lipopolysaccharide, LPS) marker (R)-3-hydroxytetradecanoic acid in cigarette smoke particles and found that smoking involved inhalation of 17.4 pmol of endotoxin per each smoked cigarette. Indoor exposure to environmental tobacco smoke (ETS) entailed inhalation of 12.1 pmol of LPS/m3 air, an amount that was 120 times higher than the levels found in smoke-free indoor air. Endotoxin is one of the most potent inflammatory agents known, hence our results may help to explain the high prevalence of respiratory disorders among smokers, and they may also draw attention to a hitherto unknown or neglected risk factor of ETS. PRACTICAL IMPLICATIONS: Endotoxin represents a largely neglected risk factor of smoking and passive smoking and this knowledge may lead to a reduced smoking.     

Solid-phase diffusion mechanism for GaAs nanowire growth

Controllable production of nanometre-sized structures is an important field of research, and synthesis of one-dimensional objects, such as nanowires, is a rapidly expanding area with numerous applications, for example, in electronics, photonics, biology and medicine. Nanoscale electronic devices created inside nanowires, such as p-n junctions, were reported ten years ago. More recently, hetero-structure devices with clear quantum-mechanical behaviour have been reported, for example the double-barrier resonant tunnelling diode and the single-electron transistor. The generally accepted theory of semiconductor nanowire growth is the vapour-liquid-solid (VLS) growth mechanism, based on growth from a liquid metal seed particle. In this letter we suggest the existence of a growth regime quite different from VLS. We show that this new growth regime is based on a solid-phase diffusion mechanism of a single component through a gold seed particle, as shown by in situ heating experiments of GaAs nanowires in a transmission electron microscope, and supported by highly resolved chemical analysis and finite element calculations of the mass transport and composition profiles.     

Laser-triggered high-voltage plasma switching with diffractive optics

High-power lasers can be used to induce ionization of gases and thereby enable rapid triggering of electrical discharge devices, potentially faster than any devices based on mechanical or solid-state switching. With diffractive optical elements (DOEs) the laser light can conveniently be directed to positions within the gas so that an electrical discharge between two high-voltage electrodes is triggered reliably and rapidly. Here we report on two different types of DOE used for creating an electrical discharge in pure argon for potential high-voltage applications. One is the diffractive equivalent of a conventional axicon that yields an extended, and continuous, high-intensity focal region between the electrodes. The other is a multiple-focal-distance kinoform-a DOE that is designed to produce a linear array of 20 discrete foci, with high peak intensities, between the electrodes. We show that DOEs enable efficient, rapid switching and may provide increased flexibility in the design of novel electrode configurations.