Attachment Failure Research Articles

Fission yeast ch-TOG/XMAP215 homologue Alp14 connects mitotic spindles with the kinetochore and is a component of the Mad2-dependent spindle checkpoint.

The TOG/XMAP215-related proteins play a role in microtubule dynamics at its plus end. Fission yeast Alp14, a newly identified TOG/XMAP215 family protein, is essential for proper chromosome segregation in concert with a second homologue Dis1. We show that the alp14 mutant fails to progress towards normal bipolar spindle formation. Intriguingly, Alp14 itself is a component of the Mad2-dependent spindle checkpoint cascade, as upon addition of microtubule-destabilizing drugs the alp14 mutant is incapable of maintaining high H1 kinase activity, which results in securin destruction and premature chromosome separation. Live imaging of Alp14-green fluorescent protein shows that during mitosis, Alp14 is associated with the peripheral region of the kinetochores as well as with the spindle poles. This is supported by ChIP (chromatin immunoprecipitation) and overlapping localization with the kinetochore marker Mis6. An intact spindle is required for Alp14 localization to the kinetochore periphery, but not to the poles. These results indicate that the TOG/XMAP215 family may play a central role as a bridge between the kinetochores and the plus end of pole to chromosome microtubules.

The effect of omitted milking on the behaviour of cows in the context of cluster attachment failure during automatic milking

In robotic milking there is always a slight chance of failure to attach the milking cluster. Attachment failure is most likely for cows whose udder conformation is less convenient for robot attachment. In general, after milking failure cows try to revisit the milking robot if they are not sent to a separate area. Since it is difficult to estimate the effect of milking failure on such a cow and her welfare in conditions of robotic milking, a specific 16-day trial was conducted on 12 cows. These cows were milked in a milking parlour with six milking stalls. Each afternoon milking, three cows were not milked. All the cows were closely observed in the cubicle house for 1 h after the afternoon milking. Thereafter, all cows were brought to the milking parlour the third time and the three unmilked cows were milked. In total, each cow was observed 12 times after milking and four times after omitted milking. The following behavioural traits were registered: time budget for the 1 h, occurrence and time until eating, drinking, lying, urination and defecation, and aggressive interactions. Milking order was defined on the basis of how often a cow came to the milking parlour in the first batch of six cows. Moreover, the data related to the milk yield and the use of the automatic feeding installation with the complete diet were analysed. After omitted milking, only the cows from the first batch stood longer in cubicles (14.2 min of 1 h) and lay less (5.4 min of 1 h) than milked cows of the same batch (respectively 7.0 min and 16.3 min for standing and lying in cubicles) ( P<0.01). After omitted milking, cows urinated earlier and more frequently (64.5%) than milked cows (36.3%) ( P<0.002) (both batches). There were no statistically significant differences in eating time and feed intake after milking and omitted milking. Milk yield per cow averaged 24.9 kg during days with omitted (delayed by 1 h) milking and 25.3 kg during the days without omitted milking ( P<0.05). It was concluded that cows show some signs of discomfort after omitted milking (urination); this discomfort seemed to be greater in cows coming earlier to the milking parlour (afterwards they preferred to stand rather than to lie). The 60% of cases of milk leakage found after omitted milking indicates that failed cluster attachment can be accompanied by an extra risk factor for the occurrence of mastitis. However, omitted milking as a treatment did not influence feeding and aggressive behaviour or milking order when unmilked cows were brought to the milking parlour the third time together with the milked cows. Our methods and results can be useful for estimating the effects of robot milking failures on a cow. Future studies should pay particular attention to high-yielding cows and to longer periods of delayed milking.

Variation in Distances Among Teats of Holstein Cows: Implications for Automated Milking1,2

Distances among teats were measured immediately prior to and immediately following milking in 912 lactations of 506 Holstein cows to assess variation due to age (parity), stage of lactation, year, and observer. Data were used to simulate success or failure to attach by the Gascoigne Melotte robotic milker. Distance between front teats premilking was nearly twice that for rear teats. When attachment of the cluster to an udder with a particular set of teat distances was simulated, excessive distance between front teats was the most frequent cause of attachment failure for third and later parities. For first parity, extremely narrow distance between rear teats was the most frequent cause of predicted attachment failure. Reduction in teat distances because of milking was proportionately much greater for distance between rear teats (45 to 50%) than for other teat distances (25 to 29%). In a study of 10 Holstein cows measured at milking and at 0, 6, 8, and 12h after milking, distances among teats increased linearly with time elapsed postmilking. Electronic storage of a profile of a cow for teat distance and adjustments for milking interval and stage of lactation can increase chances for successful cluster attachment.

Attachment reliability evaluation and failure analysis of thin small outline packages (TSOP's) with Alloy 42 leadframes

A series of studies designed to evaluate the long term surface mount reliability of Alloy 42 leaded thin small outline packages (TSOPs) using thermal cycling as an acceleration method is described. Visual inspections, pull strength, and scanning electron microscopy were used to characterize the solder joints. In addition, the solder plating, lead wetting, and aging characteristics were evaluated. Failure during thermal cycling was primarily caused by the coefficient of thermal expansion (CTE) mismatch between the package and the printed wiring board. By using acceleration factors based on solder joint strain energies induced by global and local mismatches during thermal cycling, the experimental results are extrapolated to various use conditions and life expectancies. The TSOP solder joint reliability depends on environmental conditions (cyclic temperature range, temperature maximum, and dwell time), board thickness and materials, product intended service life, and expected hazard rate limits. >

Glutaraldehyde-cross-linked meniscal allografts: clinical, gross, and histological results.

Osteoarthritic changes in the knee are often a late result of total meniscectomy. In cases of total resection, availability of a prosthetic meniscus might limit development of these changes. The objective of this research was to evaluate a glutaraldehyde-cross-linked medial meniscus as a morphologically and biologically compatible prosthesis in a canine model. Medial and lateral menisci were harvested from donor dogs, frozen in saline, and cross-linked with glutaraldehyde. Five host animals were selected and matched with donors. Glutaraldehyde-cross-linked medial menisci were implanted bilaterally in the stifle joints and one glutaraldehyde cross-linked lateral meniscus was implanted subcutaneously. Clinical results showed asymptomatic limb and joint usage during the 12 postoperative weeks. Gross and histological evaluations indicated acceptable biocompatibility. The subcutaneous implants were encapsulated with a thin fibrous tissue capsule that was only mildly inflamed. Within the joints, the anterior attachment and periphery were maintained in position by their sutures; however, there was dehiscence of the posterior suture in all cases. The articulating surfaces of the implants were intact. There was an initial loss in the quantity of proteoglycans following glutaraldehyde treatment, with significant recovery after implantation into the joints. There were significant degenerative changes (loss of proteoglycans and fibrillation) in the articular cartilage on the femoral condyle and tibial plateau most likely a result of the posterior attachment failure. It was concluded that glutaraldehyde-cross-linked meniscal allografts showed an acceptable degree of histocompatibility. However, failure of the posterior attachment interfered with testing the efficacy of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)