Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle or needle-free injection

Nursery-age pigs (n=198) were used to evaluate the difference in abscess formation at needle-free jet and conventional needle-and-syringe injection sites. Needle-free jet injection was used to administer injections in the neck and ham on one side of the animal whereas needle-and-syringe was used for neck and ham injections on the opposite side. Immediately prior to injection, the injection site surfaces were contaminated with an inoculum of Arcanobacterium pyogenes. Each pig was humanely euthanized 27 or 28days after injections. Histopathological results showed that needle-free jet injection was associated with more abscesses than needle-and-syringe injection at both neck (P=0.0625) and ham (P=0.0313) injection sites. Out of 792 injection sites, only 13 abscesses were observed, with 12 of those present at needle-free jet injection sites. Needle-free jet injection may increase the occurrence of injection site abscesses that necessitate carcass trimming at pork processing plants.     

Biosynthesis of the Myxobacterial Antibiotic Corallopyronin A

Corallopyronin A is a myxobacterial compound with potent antibacterial activity. Feeding experiments with labelled precursors resulted in the deduction of all biosynthetic building blocks for corallopyronin A and revealed an unusual feature of this metabolite: its biosynthesis from two chains, one solely PKS‐derived and the other NRPS/PKS‐derived. The starter molecule is believed to be carbonic acid or its monomethyl ester. The putative corallopyronin A biosynthetic gene cluster is a trans‐AT‐type mixed PKS/NRPS gene cluster, containing a β‐branching cassette. Striking features of this gene cluster are a NRPS‐like adenylation domain that is part of a PKS‐type module and is believed to be responsible for glycine incorporation, as well as split modules with individual domains occurring on different genes. It is suggested that CorB is a trans‐acting ketosynthase and it is proposed that it catalyses the Claisen condensation responsible for the interconnection of the two chains. Additionally, the stereochemistry of corallopyronin A was deduced by a combination of a modified Mosher's method and ozonolysis with subsequent chiral GC analyses.     

Sex Pheromone of <Emphasis Type=BoldItalic>Agriotes acuminatus</Emphasis> (Stephens, 1830) (Coleoptera: Elateridae)

The click beetle species Agriotes acuminatus is distributed in open deciduous forests throughout a large area in Europe. In order to identify its sex pheromone, gland extracts of female beetles were investigated by using GC/MS. Neryl butanoate and 2,6-dimethyl-(Z,E)-2,6-octadien-1,8-diol dihexanoate, in a ratio of approximately 1:5, were the only volatile compounds present in the extracts. Structures of both esters were confirmed by synthesis. Field experiments revealed a strong attraction of A. acuminatus males towards neryl butanoate, which could be synergistically enhanced by addition of 2,6-dimethyl-(Z,E)-2,6-octadien-1,8-diol dihexanoate. The latter compound alone did not show any attractive effect. While all Agriotes spp. investigated to date use geranyl and/or (E,E)-farnesyl esters as sex pheromones, the nerol derivatives of A. acuminatus are the first (Z)-2-configurated pheromones within this genus.     

Hot corrosion Type II of FeCr‐based model alloys for boiler and heat exchanger applications

The hot corrosion Type II of the alloys FeCr20, FeCr20Ni10, FeCr20Ni20, and FeCr20Co10 is investigated at 700°C in air + 0.5% SO₂ with deposits consisting of Na₂SO₄ and a eutectic mixture of Na₂SO₄ and MgSO₄ for 24, 100, and 300 h. The alloying elements nickel and cobalt have a positive influence when tests are conducted using a MgSO₄‐Na₂SO₄ deposit. In this case, they reduce the metal loss and increase the time to the propagation stage. In contrast, when the alloys are exposed with a Na₂SO₄ deposit, these alloying elements increase the metal loss and allow for the transition to the propagation stage because they can form molten phases with the Na₂SO₄. During the incubation stage an oxide scale forms on the FeCr20 alloy, which is thicker than the one formed during exposure without a deposit, and iron oxides are observed, which precipitate in the deposit. The propagation stage occurs by a dissolution and precipitation mechanism forming localized pitting attack. Iron is the main species that dissolves and precipitates, while chromium remains mainly as an oxide beneath the initial surface. The additional elements are found in the pit and in the salt deposit.     

Investigations of ductile damage during the process chains of toothed functional components manufactured by sheet-bulk metal forming

Sheet-bulk metal forming processes combine conventional sheet forming processes with bulk forming of sheet semi-finished parts. In these processes the sheets undergo complex forming histories. Due to in- and out-of-plane material flow and large accumulated plastic strains, the conventional failure prediction methods for sheet metal forming such as forming limit curve fall short. As a remedy, damage models can be applied to model damage evolution during those processes. In this study, damage evolution during the production of two different toothed components from DC04 steel is investigated. In both setups, a deep drawn cup is upset to form a circumferential gearing. However, the two final products have different dimensions and forming histories. Due to combined deep drawing and upsetting processes, the material flow on the cup walls is three-dimensional and non-proportional. In this study, the numerical and experimental investigations for those parts are presented and compared. Damage evolution in the process chains is simulated with a Lemaitre damage criterion. Microstructural analysis by scanning electron microscopy is performed in the regions with high mechanical loading. It is observed that the evolution of voids in terms of void volume fraction is strongly dependent on the deformation path. The comparison of simulation results with microstructural data shows that the void volume fraction decreases in the upsetting stage after an initial increase in the drawing stage. Moreover, the concurrent numerical and microstructural analysis provides evidence that the void volume fraction decreases during compression in sheet-bulk metal forming.     

Image Capture Devices Based on Charge Storage at Semiconductor-Ferroelectric Interfaces

This work shows that semiconductor-ferroelectric (SC-FE) charge storage devices are promising candidates for image capture and irradiance measurements. Incident radiation generates electron-hole pairs in the semiconductor layer, but as distinct from semiconductor pn-junctions, photocarriers are trapped at the SC-FE interface and decrease the depolarization field of the FE layer and the band bending at the interface that does not need any power supply. Since the decrease in band bending is proportional to the incident irradiance, the readout can be carried out after a certain measurement time. The paper discusses the possibilities for both a capacitive and a resistive readout. The spectral responsitivity of such SC-FE junction devices may be well designed by choosing a suitable semiconductor layer with high radiation absorption in the desired spectral range.     

Reduction of the current gain of the n-p-n transistor component ofa thyristor due to the doping concentration of the p-base

The reduction of the current amplification factor of a wide-base transistor, with growing doping concentration in the base region, is investigated. A method for the determination of the minority-carrier lifetime τ_n in the base region and the emitter Gummel number G_e is developed. The method is based on transistor structures differing only in the base width. It was found that the lifetime τ_n decreases according to the power law τ_n~N^-0.45_A. This result is analyzed for different recombination processes. Good agreement is obtained if shallow impurities acting as recombination centers are assumed. The injection-limited current gain β_γ decreases significantly with an increase in the total number of the doping concentration of the base, reaches a broad maximum, and then falls slowly. The maximum value of G_e is found to be 1.1×10¹⁴ cm^-4-s in good agreement with theoretical results. Finally, the contribution of the injection efficiency γ and the transport factor α_T to the current gain α are determined. It is found that α is limited mainly by the injection efficiency γ     

Assessment of the biodistribution and metabolism of 5-fluorouracil as monitored by 18F PET and 19F MRI: a comparative animal study

The effective clinical use of the anticancer drug 5-fluorouracil (5-FU) requires the non-invasive assessment of its transport and metabolism, particularly in the tumor and the liver, where the drug is catabolized to alpha-fluoro-beta-alanine (FBAL). In this study, the potentials and limitations of dynamic 18F PET and metabolic 19F MRI examinations for noninvasive 5-FU monitoring were investigated in ACI and Buffalo rats with transplanted MH3924A and TC5123 Morris hepatomas, respectively. Selective 5-[19F]FU and [19F]FBAL MR images were acquired 5 and 70 min after 5-FU injection using a CHESS MRI sequence. After administration of 5-[18F]FU, the kinetics of the regional 5-[18F]FU uptake were measured by dynamic PET scanning over 120 min. To allow a comparison between PET and MRI data, standardized uptake values (SUV) were computed at the same points in time. The TC5123 hepatoma showed a significantly (p < 0.002) higher mean SUV at 5 and 70 min post-5-FU injection than the MH3924A cell lines, whereas there were no significant differences between the mean SUV measured in the liver of both animal populations. In contrast to the PET data, no significant differences in the mean 5-[19F]FU and [19F]FBAL MR signal values in the tumor of both models were observed. The MR images, however, yielded the additional information that 5-FU is converted to FBAL only in the liver and not in the hepatomas.     

Novel CO(2)/N(2)O waveguide laser

We present a new design for a waveguide laser which is easily constructed from readily available materials. We have demonstrated its operation for CO(2) (8.5-W output) and N(2)O (1.5-W output).