Fault Seal Analysis in an Onshore Unconventional Gas Target, North Perth Basin.

During the 1980s, hydrocarbons were logged in aquifers during drilling of conventional gas wells in the Woodada gasfield. The gasfield is located in the North Perth Basin in Western Australia. Using Fault Seal Analysis Technology, our goal was to test the hypothesis that faults in the Kockatea Shale that are currently being reactivated may be leak prone. Wells proximal to faults with a fracture stability of greater than 5 MPa logged only methane. Wells proximal to faults with a fracture stability ≤5 MPa logged both methane and condensate in aquifers confirming that hydrocarbon leakage is correlated with critically stressed faults. This assessment assumes that fault rocks in the Kockatea Shale, which is a regional source rock and seal, comprise uncemented phyllosilicate rock. For the normal stress case, faults oriented west-north-west with moderate dip have the lowest integrity. For the strike slip stress case, faults oriented north-west and west-south-west, with moderate to steep dip have the lowest integrity. If the Kockatea Shale fault rock is assumed to be a cemented phyllosilicate, then the fracture stability increases to 14 MPa for both the normal and strike slip case. In this case, Jurassic-Permian fault intersections may be contributing to hydrocarbon leakage, however, this would require numerical modeling for confirmation. Based on leak off tests, the increase in pressure required to hydraulically fracture the formation varies between 10.7 and 13.8 MPa. The treatment pressures used during hydraulic fracturing may potentially exacerbate leakage in areas such as the Woodada gasfield.

Worker Size, Geographical Distribution, and Introgressive Hybridization of Invasive Solenopsis invicta and Solenopsis richteri (Hymenoptera: Formicidae) in Tennessee.

Worker size and geographical distribution of red imported fire ants (Solenopsis invicta Buren), black imported fire ants (Solenopsis richteri Forel), and their hybrid (S. invicta × S. richteri) (Hymenoptera: Formicidae) were evaluated from colonies sampled across Tennessee. The fire ant species and hybrid status were determined using cuticular hydrocarbon and venom alkaloid indices obtained from gas chromatography and mass spectrometry. Hybrids were the most common fire ant throughout Tennessee. With the exception of a few isolated S. invicta samples, only hybrids were found in east Tennessee, and hybrids predominated in middle Tennessee. In west Tennessee, mixed populations of S. richteri and hybrids were found. Hybrids were more common in west Tennessee than a survey performed a decade earlier. No statistical differences were detected in the average inter-colonial worker size of S. richteri and hybrids. Likewise, average worker size was not related to geographic location in Tennessee. The similarity in average worker size among hybrid colonies with a wide range of cuticular hydrocarbon and venom alkaloid values suggests introgression was not impacting ant size in colonies sampled throughout Tennessee.

Relation Between Fracture Stability and Gas Leakage into Deep Aquifers in the North Perth Basin in Western Australia.

The Kockatea Shale is a proposed target for unconventional gas development in the North Perth Basin in Western Australia. This research is concerned with correlating the extent of thermogenic gas leakage into deep aquifers overlying the Kockatea Shale with an assessment of how close the formation is to mechanical failure. Data from two petroleum exploration wells located approximately 20 km apart were considered. Both have comparable stratigraphy; however, they differ by their local tectonic setting. The stress regime is strike slip at Arrowsmith 2 well and for an assumed hydrostatic pressure the Kockatea Shale is not close to frictional limits. Minor amounts of methane and trace amounts of short chain alkanes are leaking into deep aquifers pre-development. In contrast, the stress regime is strike slip/normal at Woodada Deep well and the Kockatea Shale is close to frictional limits. Significant volumes of gas including methane and condensate are leaking into deep aquifers. The sealing capacity of the Kockatea Shale as evidenced by the variation in gas concentration in aquifers at the two sites indicates the formation is sensitive to stress. Additionally given the low permeability of the regional Kockatea Shale seal, it is assumed that at both locations gas leakage is via critically stressed faults. Deep aquifers proximal to the shale gas target are low salinity (<5000 ppm NaCl eq.) at Woodada Deep well and are saline at Arrowsmith 2 well. Based on this assessment, it is suggested that hydraulic fracture stimulation at the Woodada Deep well poses a significant environmental risk.

Glancing angle metal evaporation synthesis of catalytic swimming Janus colloids with well defined angular velocity.

The ability to control the degree of spin, or rotational velocity, for catalytic swimming devices opens up the potential to access well defined spiralling trajectories, enhance cargo binding rate, and realise theoretically proposed behaviour such as chiral diffusion. Here we assess the potential to impart a well-defined spin to individual catalytic Janus swimmers by using glancing angle metal evaporation onto a colloidal crystal to break the symmetry of the catalytic patch due to shadowing by neighbouring colloids. Using this approach we demonstrate a well-defined relationship between the glancing angle and the ratio of rotational to translational velocity. This allows batches of colloids with well-defined spin rates in the range 0.25 to 2.5 Hz to be produced. With reference to the shape and thickness variations across the catalytically active shapes, and their propulsion mechanism we discuss the factors that can lead to the observed variations in rotational propulsion.

Management of obstetric anal sphincter injuries (OASIS) in subsequent pregnancy.

Obstetric anal sphincter injuries (OASIS) are common and may greatly affect a patient's quality of life. There is very little information regarding optimum management in future pregnancies. Based upon anecdotal experience, this study describes the recommendations of a cohort of consultant obstetricians in the UK, in this clinical situation. There is limited adherence to the available national guidelines due to the absence of available equipment and expertise to perform endo-anal ultrasound and manometry. Elective episiotomy is still recommended by a small number of obstetricians but the majority of patients are routinely followed-up. Caesarean section is only advised for asymptomatic patients with a previous stage 4 tear, and for any symptomatic patient with a previous stage 3 or 4 tear, irrespective of subgrade. A request for elective caesarean section is likely to be granted, irrespective of OASIS grade. The use of postpartum endo-anal ultrasound would help identify those women in whom a further vaginal delivery is unlikely to exacerbate any symptoms of faecal incontinence.

The TRT Female Remeex System ® for recurrent female stress urinary incontinence: a 5-year follow-up study.

Conventional surgery for female stress incontinence is usually successful but recurrent cases are difficult to treat. This study of 20 such cases treated by the Remeex TRT system shows symptomatic benefit up to 5 years following insertion of the device. The benefit of this procedure is that the sling can be adjusted to the correct tension in the optimum leak position and circumstances, and anytime thereafter without the need to repeat the entire operation. As a result, the voiding dysfunction rate and need to intermittent self-catheterise is reduced, even with a low pressure urethra. The cost per procedure and complication rate is higher that standard TVT, and the device may occasionally need removal due to persistent seroma. However, the improved quality of life makes this operation an attractive option in recurrent cases of female stress incontinence.

Prolonged outbreak of meticillin-resistant Staphylococcus aureus in a cardiac surgery unit linked to a single colonized healthcare worker.

BACKGROUND: In low- as well as in high-prevalence settings, healthcare workers (HCWs) may be a substantial, under-recognized, reservoir of meticillin-resistant Staphylococcus aureus (MRSA) and an important potential source of transmission to patients. AIM: To report an outbreak of MRSA in a cardiac surgery unit in England over a 10-month period. METHODS: Cases were defined as patients and staff on the cardiac surgery unit from whom the outbreak strain was newly isolated between 20 May 2011 and 16 March 2012. Representative isolates from all cases were characterized by spa-typing, pulsed-field gel electrophoresis and multi-locus variable-number tandem-repeat analysis (MLVA). FINDINGS: Four patients appeared to acquire MRSA during their inpatient stay on the cardiac surgery unit. All four patients and one HCW were found to be carrying an identical epidemic (E)MRSA-15 strain (spa t032, pulsotype A, MLVA profile 16-6-3-1-1-17-1-4). No other members of staff were found to be colonized with MRSA. The colonized HCW was thought to be the source of the outbreak and was decolonized using a combination of nasal mupirocin, chlorhexidine body wash and oral rifampicin and doxycycline. CONCLUSIONS: This report highlights recent changes in the epidemiology of MRSA in England and suggests an important role for colonized HCWs in the transmission of MRSA to patients. Screening HCWs may provide an increasingly valuable strategy in managing linked hospital acquisitions and well-defined outbreaks where initial investigation does not reveal a source.

The effect of luminal content and rate of occlusion on the interpretation of colonic manometry.

BACKGROUND: Manometry is commonly used for diagnosis of esophageal and anorectal motility disorders. In the colon, manometry is a useful tool, but clinical application remains uncertain. This uncertainty is partly based on the belief that manometry cannot reliably detect non-occluding colonic contractions and, therefore, cannot identify reliable markers of dysmotility. This study tests the ability of manometry to record pressure signals in response to non-lumen-occluding changes in diameter, at different rates of wall movement and with content of different viscosities. METHODS: A numerical model was built to investigate pressure changes caused by localized, non-lumen-occluding reductions in diameter, similar to those caused by contraction of the gut wall. A mechanical model, consisting of a sealed pressure vessel which could produce localized reductions in luminal diameter, was used to validate the model using luminal segments formed from; (i) natural latex; and (ii) sections of rabbit proximal colon. Fluids with viscosities ranging from 1 to 6800 mPa s(-1) and luminal contraction rates over the range 5-20 mmHg s(-1) were studied. KEY RESULTS: Manometry recorded non-occluding reductions in diameter, provided that they occurred with sufficiently viscous content. The measured signal was linearly dependent on the rate of reduction in luminal diameter and also increased with increasing viscosity of content (R(2) = 0.62 and 0.96 for 880 and 1760 mPa s(-1), respectively). CONCLUSIONS & INFERENCES: Manometry reliably registers non-occluding contractions in the presence of viscous content, and is therefore a viable tool for measuring colonic motility. Interpretation of colonic manometric data, and definitions based on manometric results, must consider the viscosity of luminal content.

Hemiparkinsonism after unilateral traumatic midbrain hemorrhage in a young woman.

The relationship between head trauma and parkinsonism has been debated since James Parkinson's first description of the shaking palsy in the late 19th century. We observed in our outpatient clinic a young woman in whom hemiparkinsonism developed within 3 weeks of sustaining closed head trauma with loss of consciousness. The patient had a discrete unilateral midbrain hemorrhage on head MRI which involved the contralateral substantia nigra. The condition responded well to carbidopa/levodopa. This patient is a convincing example of posttraumatic midbrain hemorrhage causing parkinsonism.

Mitoxantrone repression of astrocyte activation: relevance to multiple sclerosis.

Mitoxantrone has been approved by the FDA for the treatment of multiple sclerosis (MS). However, the mechanisms by which mitoxantrone modulates MS are largely unknown. Activated astrocytes produce nitric oxide (NO), TNF-α, and IL-1ß, molecules which can be toxic to central nervous system (CNS) cells including oligodendrocytes, thus potentially contributing to the pathology associated with MS. MCP-1 is a chemokine believed to modulate the migration of monocytes to inflammatory lesions present in the CNS of MS patients. IL-12 and IL-23 have been demonstrated to play critical roles in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, by contributing to the development of CD4(+) T cell lineages termed Th1 and Th17, respectively. The current study demonstrates that mitoxantrone inhibits lipopolysachharide (LPS) induction of NO, TNF-α, IL-1ß, and MCP-1 production by primary astrocytes. Mitoxantrone also inhibited IL-12 and IL-23 production by these cells. Furthermore, mitoxantrone suppressed the expression of C-reactive protein (CRP). Finally, we demonstrate that mitoxantrone suppressed LPS induction of NF-κB DNA-binding activity, suggesting a novel mechanism by which mitoxantrone suppresses the expression of proinflammatory molecules. Collectively, these studies demonstrate that mitoxantrone represses astrocyte production of potentially cytotoxic molecules, as well as molecules capable of altering T-cell phenotype. These in vitro studies suggest mechanisms by which mitoxantrone may modulate inflammatory diseases including MS.

Guttural pouch mycosis in six horses in New Zealand.

CASE HISTORIES: Six horses from several geographical locations in New Zealand presented with signs of guttural pouch mycosis. All horses had experienced epistaxis within 14 days of presentation. CLINICAL FINDINGS AND TREATMENT: In five horses with epistaxis, a diagnosis of guttural pouch mycosis was made on endoscopic observation of fungal plaques in the affected guttural pouches. One of these cases died before surgery was attempted. The remaining four cases underwent ligation and balloon catheter occlusion of the internal carotid artery of the affected pouch. Three of these horses survived and were reported to be healthy 1 year after surgery. One case died from haemorrhage 8 weeks after surgery. In a sixth horse, endoscopy was carried out but the affected guttural pouch which had recently haemorrhaged was not entered. This horse underwent ligation of the internal carotid and occipital arteries of the affected side but subsequently died. A diagnosis of guttural pouch mycosis of the maxillary artery was confirmed by post-mortem examination. Histology revealed fungal hyphae within thrombi in the lumen of the maxillary artery in the affected guttural pouch. Two horses displayed signs consistent with cranial nerve damage in the guttural pouch. DIAGNOSIS: Guttural pouch mycosis. CLINICAL RELEVANCE: This is the first report of which we are aware of the diagnosis and treatment of clinical cases of guttural pouch mycosis in horses in New Zealand. Practitioners in New Zealand should be aware of the presence and manifestations of this disease and be prepared to treat or refer horses for surgical treatment before fatal haemorrhage and/or profound neurologic signs occur.

Facial swelling and discharging lesions associated with abnormalities of the mandible in kunekune pigs.

CASE HISTORIES: Four adult kunekune pigs developed facial swelling at the base of the right ear that ruptured and discharged food material. A further six pigs that had similar clinical signs were reported by members of the New Zealand Kunekune Association who responded to an email survey, one of which was confirmed by post-mortem examination. CLINICAL FINDINGS: Inside the mouth of each pig there was an opening at the junction of the body and ramus of the mandible just lateral to the most caudal visible molar that was impacted with masticated feed. The food packed into the mandible resulted in infection and progressive erosion of the medullary cavity of the bone until it reached the ramus where it eroded through the lateral cortex. The feed material then tracked through the soft tissues to form a subcutaneous abscess, which eventually ruptured resulting in a draining lesion. In Case 2, which had had the lesion for 2 years, the cavity in the mandible was lined with mucosa that had healed to the skin to produce a fistula. In all four pigs there was also a lesion in the left side of the mandible that was not as developed as that on the right side. DIAGNOSIS: The facial swellings were produced by feed material that had impacted into the mandible through an opening immediately caudal to the cheek teeth and then emerged through one or more lesions in the lateral aspect of the ramus of the mandible. CLINICAL RELEVANCE: Although it has not been previously reported, anecdotal reports and our survey suggest that this condition may occur relatively frequently in kunekune pigs. It should be considered as a differential diagnosis for facial swellings and discharging lesions in these animals.

Multi-drug-resistant Enterococcus spp. as a cause of non-responsive septic synovitis in three horses.

CASE HISTORY: Three Thoroughbred horses, a 6-week-old filly (Case 1), a 15-year-old broodmare (Case 2) and a yearling filly (Case 3), sustained synovial sepsis secondary to trauma. CLINICAL FINDINGS: Case 1 presented with a heel bulb laceration communicating with the distal interphalangeal joint. Arthroscopic lavage was performed and treatment commenced using systemic and local broad spectrum antimicrobial drugs. A pure growth of multi-drug-resistant (MDR) Enterococcus gallinarum was cultured from samples of synovium and joint fluid. Antimicrobial treatment was changed according to the susceptibility results. Response to treatment was poor and despite repeat arthroscopic lavage and intra-osseous regional perfusion of antimicrobials the filly was subject to euthanasia 24 days after the initial injury. Post-mortem examination confirmed septic synovitis, cartilage degeneration and osteomyelitis. Case 2 sustained a full thickness wound to the carpus which was sharply debrided and closed. The wound dehisced with effusion within the tendon sheath. Drainage was established and treatment included systemic broad spectrum antimicrobials, topical lavage with povodine-iodine and manuka honey infusion. A mixed infection including MDR Enterococcus faecalis was cultured from the synovial fluid. Antebrachiocarpal joint effusion developed 21 days after initial injury and joint sepsis was confirmed. Arthroscopic lavage and tendon sheath debridement were performed, followed by treatment with systemic and local antimicrobials. The mare improved and was discharged. Three months later lameness recurred and corticosteroids were administered intra-articularly. The mare became non-weight bearing lame and was subject to euthanasia. Post-mortem examination confirmed joint sepsis of the antebrachiocarpal and intercarpal joint. Case 3 presented with a complete articular open fracture of the tibial crest. Under general anaesthesia the fracture was stabilised and the wounds debrided and closed. Systemic broad-spectrum antimicrobials were administered. Six days later the wound dehisced and a bone fragment was removed. Three weeks post-surgery the wound deteriorated with a purulent discharge. Culture of the discharge revealed a mixed bacterial infection, including a MDR Enterococcus faecalis. Femoropatellar joint involvement was confirmed, and treatment included joint lavage, local and systemic antibiosis, and manuka honey instilled into the wound. The filly initially improved, and then deteriorated such that euthanasia was performed. DIAGNOSIS: All three cases had synovial sepsis with MDR Enterococcus spp. CLINICAL RELEVANCE: Increased awareness of MDR pathogens in equine wound infections is essential. Prompt diagnostic testing, appropriate therapy, infection control strategies and on-going monitoring and management are vital to limit the clinical impact of these organisms.

Granulosa theca cell tumour in a pregnant mare: concentrations of inhibin and testosterone in serum before and after surgery.

CASE HISTORY: A 14-year-old Thoroughbred mare was presented for evaluation of a rapidly enlarging ovary at 73 days gestation. The mare's owner reported behavioural changes in the mare since she returned from stud, notably aggression towards other horses. CLINICAL FINDINGS: Transrectal palpation and ultrasonography of the reproductive tract revealed a viable pregnancy, an enlarged, multiloculated right ovary, and a normal-sized left ovary with a corpus luteum present. Concentrations of inhibin and testosterone in serum were 13.8 ng/mL and 1,150 pg/mL, respectively, being markedly higher than reference ranges. Concentration of progesterone was 4.5 ng/mL, consistent with the presence of functional luteal tissue. A presumptive diagnosis of a granulosa theca cell tumour (GTCT) was made, and the ovary was surgically removed. Histopathological examination of the removed ovary confirmed a benign GTCT. At 31 days after surgery concentrations of inhibin in serum had decreased 18-fold, and testosterone had decreased 10-fold. Pregnancy was reconfirmed at 115 days gestation by rectal palpation and transrectal ultrasonography. DIAGNOSIS: Granulosa theca cell tumour associated with elevated concentrations of inhibin and testosterone in serum. CLINICAL RELEVANCE: While ovarian enlargement and aggressive behaviour may be considered normal in some pregnant mares, a GTCT should be included as a differential diagnosis. Measurement of concentrations of inhibin and testosterone in serum are useful to support a presumptive diagnosis of GTCT in mares.

Distal aortic aneurysm presumed to be secondary to an infected umbilical artery in a foal.

CASE HISTORY: A 3-month-old female Warmblood foal was presented after displaying signs of colic with pyrexia for 5 days. CLINICAL AND PATHOLOGICAL FINDINGS: The foal continued to show signs of colic, frequently passed urine, and was pyrexic with an elevated white blood cell count. The umbilical stalk was thickened but there was no evidence of purulent material. Exploratory laparotomy revealed an enlarged left umbilical artery remnant tightly adhered to the bladder wall. The left umbilical artery continued to an aneurysm involving the distal aorta. The foal was subject to euthanasia and post-mortem examination confirmed a spherical aortic aneurysm, in the dorsal midline caudal to the kidneys that contained a large thrombus. Histopathological examination revealed inflammation and necrosis of the tunica intima and tunica media of the left umbilical artery with suppuration and bacterial colonies evident in the periarterial tissues. DIAGNOSIS: Infected aortic aneurysm presumably caused by an umbilical artery infection. CLINICAL RELEVANCE: A previously undetected umbilical infection appears to have resulted in an unusual delayed complication causing signs of colic in a foal. Veterinarians should be aware of this condition, and the possibility that it may be a cause of signs of colic in foals. Diagnosis based on ultrasonography should be possible, but may require sedation, visceral analgesia and careful examination.

Aminoindanes--the next wave of 'legal highs'?

Due to its closed ring system, 2-aminoindane is a conformationally rigid analogue of amphetamine. Internet websites offering synthetic compounds as 'research chemicals' have recently been advertising 5,6-methylenedioxy-2-aminoindane (MDAI), 5, 6-methylenedioxy-N-methyl-2-aminoindane (MDMAI), 5-iodo-2-aminoindane (5-IAI), and 5-methoxy-6-methyl-2-aminoindane (MMAI). The chemistry, pharmacology, and toxicological aspects of this new class of psychoactive substances are reviewed, as these could become the next wave of 'legal highs'.

Cutaneous fungal granulomas due to Alternaria spp. infection in a horse in New Zealand.

Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.