On phase transition layers in certain micro-damaged two-phase solids

A continuum model of a moving transition layer separating two different solid phases of a certain micro-damaged material is proposed. An application of this model to the analysis of the propagation of this layer in a micro-cracked solid is shown. This revised version was published online in August 2006 with corrections to the Cover Date.     

Space–time clustering of seismic events and hazard assessment in the Zabrze-Bielszowice coal mine,Poland

The results of the statistical analysis of seismic activity recorded in the “Zabrze-Bielszowice” coal mine in Poland are presented in this article. The monitoring was conducted by a small network consisting of four triaxial geophones deployed in vertical holes in the roof. For over 1000 seismic events recorded during the two month's experiment, the location of sources was realized. The seismic sources were mostly located ahead of the active face of the longwall. Since the first day of the monitoring, cluster analysis was sequentially performed for increasing number of sources. At the end of the experiment, 31 clusters were identified. They consisted of different numbers of events and were separated in space. About 40% of the events were not included in the clusters. For each large cluster, hazard analysis was separately performed. The hazard function evaluated for the largest cluster was compared with hypocenters of high energy tremors (E>1000 J) recorded by the geophones in that area. For some cases, recorded tremors occurred after an abrupt decrease of hazard function, but only one of them was located in the vicinity of the appropriate cluster. We concluded that for the analyzed cluster, a correlation between evaluated hazard function and time occurrences of the high energy tremors existed. Except for one case, there is no space correlation between analyzed clusters and high energy tremors.     

A rare case of ovarian leiomyoma. A case report with review of literature]

We report an exceptional case of ovarian leiomyoma in 73 years old patient. Leiomyoma of the ovary is a very rare tumor. Most cases are asymptomatic, this benign neoplasm is usually found incidentally on routine pelvic examination, at surgery or at autopsy. The available literature is reviewed. The possible histogenesis of ovarian leiomyoma was discussed.     

Contents of total and protein-bound carbohydrates are low in leukemic leukocytes from patients with acute myelogenous leukemia

The successful approach to the failed knee with bone deficiency is dependent upon thorough planning prior to surgery in order to have the resources available in terms of adequate bone allograft and suitable revision implants. The approximate size of bone stock deficiency can be calculated from preoperative radiographs and similarly ligamentous incompetence can often be diagnosed clinically prior to surgery. Smaller defects of up to 1 to 1.5 cm in depth and localized in the main to a single side of the tibial plateau or to a single femoral condyle can be dealt with using smaller grafts that may be local autograft or allograft, or modular wedges. Larger tibial defects can be compensated for using conventional revision systems by thicker polyethylene and augmented baseplates, but once the flexion-extension gap reaches approximately 40 mm this is no longer possible and structural graft or customized componentry becomes necessary. Femoral defects larger than about 1 cm that cannot be made up by augments necessitate grafting. The need to use a large proximal tibial allograft also may dictate the operative approach used to expose the joint, especially in the situation of a multiply-operated tight knee. In such cases the use of a quadriceps turndown may be more advisable than the use of a tibial tubercle osteotomy as the osteotomy may well not have an adequate bed to heal to following the reconstruction. Several series have reported cases of patellar tendon avulsion and the clinical results following this complication usually are not satisfactory. Preoperatively it is important to identify, if possible, the case that is likely to require a more extended approach because of a tight soft tissue envelope. The reports of results of series of revision total knee arthroplasty in the setting of significant bone loss are at present confined to short-term followup. The clinical results of these series are satisfactory at this early point in time, but decision regarding the durability of reconstructions requiring major structural allografting awaits longer-term study. Of concern is the devastating complication of infection following such revision surgery, the risk of which is amplified in the setting of prior infection. In addition, the long-term viability of major structural grafts in the setting of loading is uncertain as the risk of graft collapse in the process of incorporation is not known. Notwithstanding these concerns, major grafting is sometimes the only recourse to achieve satisfactory revision of a failed arthroplasty. The use of such major grafts is therefore cautiously supported and because of the risks inherent in such surgery we believe that such surgery should be carried out in the setting of specialist interest units.     

Macroscopic modelling of prestressed microperiodic elastic media

Summary. The aim of this contribution is to formulate and apply a macroscopic model for the analysis of the dynamics and stability of prestressed microperiodic elastic media. This modelling problem has been solved by Kolpakov [1] using the asymptotic homogenization method. However, the method used in [1] neglects the effect of the period length on the macroscopic (overall) solid behavior. To eliminate this drawback we propose a nonasymptotic modelling approach which is a certain generalization of the tolerance averaging method recently presented in [2] and a series of papers. The presented general results are illustrated by the analysis of a certain special problem.