An approach for selecting a high-density polyethylene (HDPE) geomembrane (GMB) for a long design life is described and illustrated for five 2 mm thick textured GMBs when immersed in a simulated municipal solid waste leachate (L3) and two simulated leachates representative of low-level radioactive waste leachates (L7 and L9) for 9–16 months at a range of temperatures. Although made from the same nominal resin, substantial differences are reported in both the initial properties and the rate of antioxidant depletion for the five GMBs. At an expected operating liner temperature of 10 °C and immersed in L3, the projected time to antioxidant depletion for the five GMBs ranges from 125 to over 2000 years. The antioxidant depletion in leachates L7 and L9 were similar or slower than in leachate L3. There was no evidence of traditional thermal-oxidative degradation reported over the 9–16 months of monitoring; however, there was a significant reduction in stress crack resistance due to physical ageing ranging between 30% and 70% of the initial value. Two GMBs are considered highly likely to have service life well in excess of the required design life of 550 years. It is suggested that the proposed approach could be adopted for selecting GMBs for other projects that require a long design life.
A two-year-old ewe was presented to Veterinary Hospital, with a sudden onset of diarrhea, epistaxis, reluctance to move and recumbency which eventually led to its death. After necropsy and tissue sample collection for further examinations, histopathological study revealed large submucosal vascular structures with some thrombotic and blood filled spaces indicator of nasotracheal cavernous hemangioma, diffuse lymphocytic enteritis, hepatic diffuse mild vacuolar degeneration, severe pulmonary hyperemia and edema, cardiac and skeletal muscle sarcocystosis with severe hyperemia and fragmentation of cardiac muscle fibers, mild perineuronal edema of the spinal cord, hyperemia and perineuronal (Purkinje cell) edema in the cerebellum, hyperemia with perineuronal and perivascular edema in the cerebrum, severe hyperemia with diffuse severe acute tubular necrosis, and mild intratubular and intrabowman's capsular space proteinaceous material in the kidney. To the authors' knowledge, this is the first case report of Nasotracheal hemangioma in sheep in Iran. with progressive lameness of the left forelimb of 2.5 months duration, a dilation of the deep flexor tendon sheath with a firm elastic consistency and a pronounced tenderness was noted and diagnosed as synovial hemangioma on the basis of the histopathological, immunohistochemical and ultrastructural features [7]. A case of concurrent intranasal hemangioma and tetracycline induced gastritis and ulceration in a dog has been reported [8]. Case Presentation We present a case of nasotracheal cavernous hemangioma in an Arabi sheep, which was part of a flock of 140 sheep and 23 goats, located in Damavand, the capital of Damavand County, Tehran Province. On 7 Feb 2015, a two-year-old ewe was presented to veterinary hospital with a sudden onset of diarrhea, epistaxis, and reluctance to move and recumbence which eventually led to its death. Necropsy and sample collection were undertaken for further examinations. Tissue samples were obtained from nasotrachea, kidney, heart, cerebrum, cerebellum, spinal cord, skeletal muscle, lung, liver and small intestine. All specimens were fixed in 10% neutral buffered formalin, embedded in paraffin, sectioned to a thickness of 4 μm, and stained with hematoxylin and eosin. Histopathological findings are summarized in Table 1, Figures 1-3. Discussion Intranasal tumors in dogs are extremely rare, less than 1% of all cancers, but the malignant types of intranasal vascular tumors have a little higher incidence. Approximately two-thirds of canine intranasal tumors are carcinomas and the remaining third is comprised of sarcomas [8,9]. Hemangioma and hemangiosarcoma are associated with blood clotting affects with decreased platelet count and increased blood clotting time [8]. There are few reports of this tumor in sheep. Only a round-shaped, pedunculated, soft and dark red mass on gingival compartment of midlateral edge of mandibular region of a five-year-old Iranian cross breed ewe has been reported [5].
Congenital malformations occur sporadically in cattle; however, congenital structural and functional disorders of the nervous system are rather common in ruminants. Among the numerous causes of congenital nervous system defects, infectious agents are highlighted in this paper. Virus-induced congenital malformations are well known, among which those caused by bovine viral diarrhoea virus (BVDV), Akabane virus (AKAV), Schmallenberg virus (SBV), Bluetongue virus (BTV), and Aino virus (AV) are the most studied. In this study, we specify and categorise macroscopic and histopathological lesions in the brain of 42 newborn calves suffering from severe neurologic signs and diagnosed with BVDV and AKAV infection. Following a complete necropsy, specimens were collected from the brains to track the presence of BVDV, AKAV and SBV utilising reverse transcription polymerase chain reaction. Of the 42 examined calves, 21 were BVDV positive and 6 were AKAV positive, while 15 brains were negative for the studied agents. Regardless of the aetiology, cerebellar hypoplasia, hydranencephaly, hydrocephalus, porencephaly, and microencephaly were detected. Cerebellar hypoplasia was the most common lesion seen in both BVDV-positive and AKAV-positive cases. Virus-induced necrosis of the germinative cells of the external granular layer of cerebellum, as well as vascular damages, are believed to be the underlying causes of cerebellar hypoplasia. BVDV was the most important aetiological agent of such cases in this study.
The degradation behaviour of five multilayered textured white geomembranes (GMBs) is investigated when immersed in two synthetic low-level waste (LLW) leachates with pH 7 and 9 at a range of temperatures (40-85oC) for 48-55 months. Results are compared to the performance of the GMBs in synthetic municipal solid waste (MSW) leachate. Increasing pH from 7 to 9 gives slightly faster antioxidant depletion in LLW leachate. The estimated time to nominal failure for the GMBs is at least 20% longer in LLW leachate than in MSW leachate containing surfactant that accelerates both antioxidant depletion and stress cracking. Thus, MSW leachate can be used as a conservative proxy to estimate the service-life of a GMB in contact with LLW leachate. Two GMBs are considered very highly likely to meet the required 550-year design life of the near surface disposal facilities even based on the most conservative prediction of the time to nominal failure for the GMBs.
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