Large volume dye spread in transversus abdominis plane block via three injection sites: a cadaveric study

Background: Transversus abdominis plane (TAP) block is a recently described regional anaesthesia technique that provides analgesia for the abdominal wall. Three access points for injection have been described: via the lumbar triangle of Petit (LTOP), via the midaxillary line and via the subcostal region (SC). This study aimed to investigate the spread of dye following injection via all 3 sites with a large volume injectate. Materials and Methods: 24 hemiabdomens were injected with 40 mL 25% black food dye: 8 via the LTOP) 4 via the MAL, 4 via the SC. Dissection was performed to reveal the extent of nerve involvement and dye spread. Results: Variation in the size and shape of the LTOP was found between cadavers. Mean areas of dye spread (range of nerve involvement) in the remaining 16 hemiabdomens for LTOP, MAL and SC were 77.9 cm2 (T10-ilioinguinal), 50.3 cm2 (T10-ilioinguinal) and 91.3 cm2 (T7-ilioinguinal) respectively. Communications were seen between nerves within the TAP in one dissection. Dye staining was seen to involve nerves outside the TAP. Conclusion: Subcostal injection gives more superior dye spread, with a greater area and awider range of nerve involvement. This should perhaps be the preferred injection site, and could have broader indications

Steam as the working fluid for power recovery from exhaust gases by means of screw expanders

Rankine cycle systems, using steam as a working fluid, are not well suited to the recovery of power fromheat sources in the 300-450 °C temperature range, such as internal combustion engine exhaust gases, mainly due to the relatively large enthalpy of vaporization of water. Admitting the steam to the expander as vapour approximately 50 per cent dry, would be preferable but turbines cannot be used to expand vapours from this state. However, screw expanders can operate well in this mode. It is shown that, apart from being environmentally benign and free from flammability risks, a screw-driven wet steam cycle system can recover power from engine exhaust gases, with comparable efficiencies to turbine-driven systems using organic fluids at a significantly lower cost per unit output

Steam as the working fluid for power recovery from exhaust gases by means of screw expanders

Rankine cycle systems, using steam as a working fluid, are not well suited to the recovery of power fromheat sources in the 300-450 °C temperature range, such as internal combustion engine exhaust gases, mainly due to the relatively large enthalpy of vaporization of water. Admitting the steam to the expander as vapour approximately 50 per cent dry, would be preferable but turbines cannot be used to expand vapours from this state. However, screw expanders can operate well in this mode. It is shown that, apart from being environmentally benign and free from flammability risks, a screw-driven wet steam cycle system can recover power from engine exhaust gases, with comparable efficiencies to turbine-driven systems using organic fluids at a significantly lower cost per unit output

Structural stability of cooling flows

Three-dimensional hydrodynamical simulations are used to investigate the structural stability of cooling flows that are episodically heated by jets from a central AGN. The radial profile of energy deposition is controlled by (a) the power of the jets, and (b) the pre-outburst density profile. A delay in the ignition of the jets causes more powerful jets to impact on a more centrally concentrated medium. The net effect is a sufficient increase in the central concentration of energy deposition to cause the post-outburst density profile to be less centrally concentrated than that of an identical cluster in which the outburst happened earlier and was weaker. These results suggest that the density profiles of cooling flows oscillate around an attracting profile, thus explaining why cooling flows are observed to have similar density profiles. The possibility is raised that powerful FR II systems are ones in which this feedback mechanism has broken down and a runaway growth of the source parameters has occurred.Comment: 4 pages, 2 figure

Development and Validation of Novel PCR Assays for the Diagnosis of Bovine Stephanofilariasis and Detection of Stephanofilaria sp. Nematodes in Vector Flies

Background: Stephanofilaria spp. nematodes are associated with cutaneous lesions in cattle and other livestock and mammalian wildlife species. In Australia, Haematobia irritans exigua, commonly known as buffalo fly (BF) transmits a well-described but presently unnamed species of Stephanofilaria, which has been speculatively implicated in the aetiology of BF lesions. The sensitivity of current techniques for detecting Stephanofilaria spp. in skin lesions and vector species is low, and there is no genomic sequence for any member of the genus Stephanofilaria currently available in sequence databases. Methods: To develop molecular assays for the detection of the Australian Stephanofilaria sp., skin biopsies were collected from freshly slaughtered cattle with typical lesions near the medial canthus. Adult nematodes and microfilariae were isolated from the biopsies using a saline recovery technique. The nematodes were morphologically identified as Stephanofilaria sp. by scanning electron microscopy. DNA was extracted and the internal transcribed spacer 2 (ITS2) region of rDNA, and the cytochrome c oxidase subunit 1 (cox1) region of mtDNA was amplified and sequenced. Stephanofilaria sp. specific polymerase chain reaction (PCR) and qPCR assays (SYBR Green® and TaqMan™) were developed and optimised from the novel ITS2 sequence obtained. The specificity of each assay was confirmed by testing against nematode species Onchocerca gibsoni and Dirofilaria immitis, as well as host (bovine) and BF DNA. Results: Scanning electron microscopy of the anterior and posterior ends of isolated nematodes confirmed Stephanofilaria sp. A phylogenetic analysis of the cox1 sequence demonstrated that this species is most closely related to Thelazia callipaeda, a parasitic nematode that is a common cause of thelaziasis (or eyeworm infestation) in humans, dogs, and cats. Both conventional and qPCR assays specifically amplified DNA from Stephanofilaria sp. Conventional PCR, TaqMan™, and SYBR Green® assays were shown to detect 1 ng, 1 pg, and 100 fg of Stephanofilaria DNA, respectively. Both qPCR assays detected DNA from single Stephanofilaria microfilaria. Conclusion: Molecular diagnostic assays developed in this study showed high specificity and sensitivity for Stephanofilaria sp. DNA. The availability of an accurate and sensitive PCR assay for Stephanofilaria will assist in determining its role in the pathogenesis of cattle skin lesions, as well as in understanding its epidemiological dynamics. This assay may also have application for use in epidemiological studies with other species of Stephanofilaria, most particularly closely related S. stilesi, but this will require confirmation

Probabilistic modeling of heteroscedastic laboratory experiments using Gaussian process regression

This paper proposes an extension to Gaussian process regression (GPR) for data sets composed of only a few replicated specimens and displaying a heteroscedastic behavior. Because there are several factors that are out of the control of experimenters, it is often impossible to reproduce identical specimens for a same experiment. Moreover, observations from laboratory experiments typically display a heteroscedastic interspecimen variability. Because experiments and specimen manufacturing are expensive, it is uncommon to have more than three specimens to build a model for the observed responses. The method proposed in this paper uses GPR to predict each tested specimen using a shared prior structure and models the global heteroscedastic behavior by combining observations using conjugate prior distributions. An application of the method to high-performance fiber-reinforced concrete experiments highlights fiber addition benefits for reducing water permeability caused by macrocracks

Improving the biological interfacing capability of Improving the biological interfacing capability of diketopyrrolopyrrole polymers via p-type doping

Polydiketopyrrolopyrrole terthiophene (DPP3T), a high-performing conjugated polymer, holds great potential as active material for bioelectronics. Herein, its surface properties are modulated through p-type doping, thereby enhancing the cell behaviour on top of the doped films

Role of Staphylococcus agnetis and Staphylococcus hyicus in the Pathogenesis of Buffalo Fly Skin Lesions in Cattle

Buffalo flies (Haematobia irritans exigua) are hematophagous ectoparasites of cattle causing production and welfare impacts in northern Australian herds. Skin lesions associated with buffalo fly infestation and Stephanofilaria nematode infection are manifested as focal dermatitis or ulcerated areas, most commonly on the medial canthus of the eye, along the lateral and ventral neck, and on the abdomen of cattle. For closely related horn flies (Haematobia irritans irritans), Staphylococcus aureus has been suggested as a contributing factor in the development of lesions. To investigate the potential role of bacterial infection in the pathogenesis of buffalo fly lesions, swabs were taken from lesions and normal skin, and bacteria were also isolated from surface washings of buffalo flies and surface-sterilized homogenized flies. Bacterial identification was conducted by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) and strain typing by repetitive sequence-based PCR (rep-PCR) and DNA sequencing to determine species similarity and virulence factors. Of 50 bacterial isolates collected from lesions, 38 were identified as Staphylococcus agnetis and 12 as Staphylococcus hyicus, whereas four isolates from normal skin were S. hyicus and one was Mammaliicoccus sciuri. Of the Staphylococcus isolates isolated from buffalo flies, five were identified as S. agnetis and three as S. hyicus. Fifty percent of the buffalo fly isolates had rep-PCR genotypic patterns identical to those of the lesion isolates. Genome sequencing of 16 S. agnetis and four S. hyicus isolates revealed closely similar virulence factor profiles, with all isolates possessing exfoliative toxin A and C genes. The findings from this study suggest the involvement of S. agnetis and S. hyicus in buffalo fly lesion pathogenesis. This should be taken into account in the development of effective treatment and control strategies for lesions