Large-scale molecular dynamics simulations of dislocation intersection in copper

The results of massively parallel three-dimensional molecular dynamics simulations of the perpendicular intersection of extended dislocations in copper are reported. The intersection process, which involves three of the four possible 111 glide planes in the face-centered cubic lattice, begins with junction formation, followed by unzipping, partial dislocation bowing, cutting, and, finally, unit jog formation. The investigation provides insights into this complex atomistic process, which is currently not accessible to experimental investigation.     

THz-imaging: a new method for density mapping of wood

Summary This paper presents a new technique for fast and non-intrusive density mapping of wood based on far-infrared spectroscopy. The transmission of a piece of beech 1.7 mm thick is investigated between 0.1 and 2.5 THz. In this spectral range we find wood to be fairly transparent, but density inhomogeneities and structural details such as annual rings become visible in the transmission profile. The measured absorption correlates well with the wood density independently obtained by the gravitometric-volumetric method. Thus it finally becomes possible to transform the THz images into 2-dimensional density maps.The skillful technical help of Mrs. M. Rinas is greatly appreciated.     

Clinical evaluation of the CRIF 4.5/5.5 system for long-bone fracture repair in cattle

OBJECTIVE: To report clinical evaluation of the clamp rod internal fixator 4.5/5.5 (CRIF 4.5/5.5) in bovine long-bone fracture repair. STUDY DESIGN: Retrospective study. ANIMALS: Cattle (n=22) with long-bone fractures. METHODS: Records for cattle with long-bone fractures repaired between 1999 and 2004 with CRIF 4.5/5.5 were reviewed. Quality of fracture repair, fracture healing, and clinical outcome were investigated by means of clinical examination, medical records, radiographs, and telephone questionnaire. RESULTS: Successful long-term outcome was achieved in 18 cattle (82%); 4 were euthanatized 2-14 days postoperatively because of fracture breakdowns. Two cattle had movement of clamps on the rod. Moderate to severe callus formation was evident in 11 cattle 6 months postoperatively. CONCLUSIONS: Movement of clamps on the rod was recognized as implant failure unique to the CRIF. This occurred in cattle with poor fracture stability because of an extensive cortical defect. The CRIF system may not be ideal to treat metacarpal/metatarsal fractures because its voluminous size makes skin closure difficult, thereby increasing the risk of postoperative infections. CLINICAL RELEVANCE: CRIF cannot be recommended for repair of complicated long-bone fractures in cattle.     

Surgical treatment of coxofemoral luxation in two cattle

A three-week-old Holstein Friesian calf and a 20-month-old Jersey heifer were referred to the Department of Farm Animals, University of Zurich, because of coxofemoral luxation. Both animals were moderately lame on the affected hind limb, which was swollen in the hip region and appeared to be adducted and shorter than the contralateral normal hind limb. Radiographs of the affected hips confirmed craniodorsal displacement of the femur. In both animals, traction and open reduction was carried out under general anaesthesia. The joint capsule, which was severely torn, was repaired using suture material or a non absorbable mesh. In the calf, two 4.5-mm screws and washers were placed in the dorsal rim of the acetabulum. Strong non-absorbable suture material of USP 6 in size was placed around each screw and through a pre-drilled hole in the femoral neck and back to the screw in a figure-8 pattern. The sutures were tied and the screws tightened. In the heifer, a non-absorbable mesh was attached to the dorsal acetabular rim using three 4.5-mm cortical screws.The mesh was sutured to the joint capsule at the femoral neck using strong non-absorbable suture material in a simple continuous pattern. Complications were not encountered during the postoperative period. Six months after discharge, both animals were in good general health, although the heifer had mild lameness and muscle atrophy in the operated limb.     

Investigation of diabetes mellitus in Burmese cats as an inherited trait: a preliminary study

AIM: To investigate, in a pilot study, a possible genetic component to type 2 diabetes mellitus (T2D) in Burmese cats in New Zealand by analysing pedigree data.

METHODS: Pedigrees were obtained for 305 Burmese cats living in New Zealand; diabetes was diagnosed in 19 of these due to presence of polyuria and polydipsia, persistent concentrations of glucose in plasma >16?mmol/L and glucosuria prior to insulin treatment. Pedigrees were also submitted for 16 cats with no clinical signs of T2D. The remaining 270 cats were unobserved relatives of these individuals. Inbreeding coefficients and heritability were calculated, and a single major locus model segregation analysis was conducted using pedigree analysis software.

RESULTS: Nineteen cats were diagnosed with T2D. Males (n = 14) and females (n = 5) were both affected, suggesting that the gene or genes causing diabetes are autosomal rather than sex-linked. Examination of the pedigree revealed few signs of fully penetrant dominant gene action: diabetes was ostensibly rarely seen in sequential generations and nearly always skipped at least one and often more generations; apparently unaffected offspring of apparently unaffected parents sometimes produced affected progeny. The mean relatedness of the affected animals within the core pedigree (16 diabetic cats) was 0.049, and mean inbreeding 0.033. Based on 100,000 permutations of the trait values, the expected relatedness of a random sample of 16 animals taken from the phenotyped animals would be 0.013 (SD 0.007) (permutation p = 0.0009). The observed inbreeding was also significant (permutation p= 0.02).

Heritability was estimated to be 9 (95% CI = 0–57)% assuming all animals with unknown status were unaffected. The best fitting genetic model was a major gene model with dominant expression with the risk allele frequency at 15% with 60% penetrance.

CONCLUSIONS: In this pilot study the increased inbreeding in the cases, lack of likely sampling bias, the increased frequency of T2D in Burmese, and small number of breed founders are consistent with the involvement of a major locus in diabetes in Burmese cats with a significant risk allele prevalence. However, low case numbers meant this could not be unambiguously confirmed. A genome-wide association study may be useful for investigating the genetic cause of T2D.     

Nasolabioplasty after rupture of the nasal ring in cattle

In 25 cases of muzzle and nasal septum injuries operative treatment was performed by different methods. In conventional nasolabioplasty (n = 23) horizontal mattress sutures were used, the free parts of the thread passing through pieces of rubber tube. In two bulls, suffering from such a rupture the second time, a new surgical technique was applied. To prevent stenosis of the nostrils, the nasal septum was reconstructed by cutaneous pedicle graft. The techniques of both methods are described and illustrated. Healing was observed in all cases.