Role of the contact layer between liquid and solid on a solidification process

The object of this paper is the presentation of a theoretical solidification model of heat-conducting liquid metal flowing near of a cold plate. The problem of the unsteady behaviour both of the frozen metal layer and of the cold plate is studied analytically. Influence of the contact layer between the frozen layer and the cold plate on the solidification process is also studied. The results in the form of the analytical formula and the graphs are presented and compared with the other results.     

Invasion of cytotrophoblastic JEG-3 cells is stimulated by hCG in vitro

Trophoblast invasion into the uterine wall is controlled by many factors. Previously, a human chorionic gonadotropin (hCG) receptor has been found to be expressed on invasive trophoblast as well as on choriocarcinoma cells implying a possible role for the hormone in trophoblast invasion. Therefore, this study examined the role of hCG in the invasion of trophoblastic (JEG-3) cells. Increasing hCG concentrations were applied in a trophoblast invasion model, JEG-3, through matrigel-coated filters. The proliferation was quantified by WST-1 cleavage assay. Cell migration was studied by examining the number of cells that had passed the uncoated porous (8-microm pore size) filters. After staining, filters were examined microscopically for cells on the underside of the membrane. A quantitative protease assay was also performed. Flow cytometric analysis of alpha5 and alpha6 integrin subunits, which are essential for interactions between cells and extracellular matrix, was performed. hCG increased significantly (P<0.01) the in vitro invasion of trophoblastic JEG-3 cells in a dose-dependent manner. Migration was also increased by hCG (P<0.01). However, cell proliferation remained unchanged. The second messenger analogue dibutyryl cAMP (db cAMP) and the cAMP elevating factor (forskolin) mimicked the effects of hCG by stimulating a dose-dependent increase of trophoblastic cell UEG-3) invasion. The collagenolytic activity of trophoblastic cells (EG-3) was increased by hCG stimulation. No changes were shown in the expression of alpha5 and alpha6 integrin subunits on JEG-3 cells. In vitro hCG is a regulatory factor of invasion and migration in trophoblastic JEG-3 cells, whereas proliferation is not influenced. The endogenous production of hCG by the trophoblast in vivo implies an autocrine control of invasion processes by hCG.     

Dynamical cooling of semiconductor by contact layer

The subject of this paper is the presentation of a simple theoretical model of cooling of a semiconductor. The problem of the unsteady behaviour both of the semiconductor and of the cold plate that are in touch by the contact layer was studied analytically. The influence of the parameters of the materials and the cooling conditions was investigated. The results in the form of an analytical formula and graphs are presented and the heat stream is compared with the experimental results.     

Biomass productivity and phytoremediation potential of Salix alba and Salix viminalis

The aim of this work was to determine selected Salix clones’ capacities for biomass production and accumulation of heavy metal ions. Determination of the relationship between sorption of metals and biomass productivity was a further purpose of this study. Eight Salix viminalis cultivars and one Salix alba cultivar were analyzed. The taxa characterized by greatest biomass production were S. alba var. Chermesina and S. viminalis ‘1056’ (respectively 6.8 and 4.3 kg of fresh mass per shrub per year).The results have revealed significant differences among clones. The clones most effective in accumulating all five metals were S. viminalis ‘1154’ and ‘1054’. The studied Salix population was significantly diverse as regards accumulation efficiency. The differences between the highest and lowest heavy metal content in extreme clones were for: Cd 84%, Cu 90%, Hg 167%, Pb 190% and Zn 36%. At the same time, significant differences were observed in Salix structure. The greatest cellulose content was observed in S. viminalis ‘Sprint’ (49.69%) and the lowest in S. viminalis ‘1059’ (42.09%).     

The use of the Synthes 7.3-mm. cannulated screw in rearfoot and ankle surgery: a preliminary prospective study

The authors present a preliminary prospective study of the Synthes 7.3 mm. cannulated screw used in 31 rearfoot and ankle surgeries on 29 patients. The patients had a variety of rearfoot and ankle procedures performed, in which a total of 75 screws were placed across 47 arthrodesis or osteotomy sites. The percentage of union or healing was 95.74% for the joints or sites involved. The average healing time was 2.71 months. The techniques for placement of the screw are described.     

Overproduction of the Brucella melitensis heat shock protein DnaK in Escherichia coli and its localization by use of specific monoclonal antibodies in B. melitensis cells and fractions

The Brucella melitensis dnaK gene was amplified by the polymerase chain reaction using primers chosen according to the published sequence of B. ovis and cloned in multiple copy plasmids enabling expression under the control of the Plac promoter. Monoclonal antibodies (mAb) obtained by immunizing mice with B. melitensis B115 cell wall (CW) fraction or by infecting mice with virulent B. melitensis strain H38 and recognizing a 73-kDa band in immunoblotting of the B. melitensis CW fraction reacted with the cloned dnaK gene product and were thus shown to be specific for the heat shock protein DnaK. The anti-Dnak protein mAbs did not react with Escherichia coli control cells or cell lysates and could therefore be specific to Brucella DnaK protein epitopes. These mAbs were further used to study overproduction of the DnaK protein. B. melitensis DnaK overproduction in E. coli resulted in a defect in cell septation and formation of cell filaments. Immunogold labelling with the mAbs and electron microscopy localized the DnaK protein inside as well as outside the E. coli cells, probably resulting from lysis due to toxicity of the overproduced DnaK protein. These results indicated that overproduction of the B. melitensis DnaK protein in E. coli had similar physiological consequences as that of E. coli overproduced in E. coli. The DnaK protein localization in B. melitensis cells was essentially cytoplasmic, as shown by immunoelectron microscopy. Heat shock treatment of these cells resulted in increased binding of mAbs and labelling in the cytoplasm. However, in subcellular fractions the DnaK protein was predominantly found in the cell envelope fraction of B. melitensis, which could perhaps be due to interaction of the DnaK protein with membrane proteins.     

Bovine bone grafting in occipito-cervical fusion for atlanto-axial instability in rheumatoid arthritis

Bovine bone chips (Surgibone) were used in occipito-cervical fusion in nine patients with atlanto-axial instability due to rheumatoid arthritis. The patients were examined with CT 12-15 months after surgery. Graft resorbtion was observed in one patient. The other 8 patients showed preserved grafts, in most cases the grafts appeared to be in contact with the underlying bone. One patient was revised, and at the grafted site a bony bridge was found. In conclusion, the use of bovine chips in posterior occipito-cervical fusion will not lead to predictable bone union. However, there seem to be exceptions to that rule.     

Independent-Tree Ad hoc MulticAst Routing (ITAMAR)

Multicasting is an efficient means of one to many communication and is typically implemented by creating a multicasting tree. Because of the severe battery power and transmission bandwidth limitations in ad hoc networks, multicast routing can significantly improve the performance of this type of network. However, due to the frequent and hard-to-predict topological changes of ad hoc networks, maintenance of a multicasting tree to ensure its availability could be a difficult task. We borrow from the concept of Alternate Path routing, which has been studied for providing QOS routing, effective congestion control, security, and route failure protection, to propose a scheme in which a set of multicasting trees is continuously maintained. In our scheme, a tree is used until it fails, at which time it is replaced by an alternative tree in the set, so that the time between failure of a tree and resumption of multicast routing is minimal. In this paper, we introduce the basic scheme, termed ITAMAR, which is a framework for efficient multicasting in ad hoc networks. We present a number of heuristics that could be used in ITAMAR to compute a set of alternate trees. The heuristics are then compared in terms of transmission cost, improvement in the average time between multicast failures and the probability of usefulness. Simulations show significant gains over a wide range of network operational conditions. In particular, we show that using alternate trees has the potential of improving mean time between interruption by 100–600% in a 50 node network (for most multicast group sizes) with small increase in the tree cost and the route discovery overhead. We show that by renewing the backup tree set, probability of interruptions can be kept at a minimum at all times and that allowing some overlap among trees in the backup set increases the mean time between interruptions.     

The use of ultrasonography for the detection of retained wooden foreign bodies in the foot

The efficacy of ultrasonography for the detection of wooden foreign bodies in the foot was analyzed retrospectively. Twenty patients underwent real-time, high-resolution ultrasound studies (7.5 or 10 MHz, linear array transducers) to rule out the presence of a wooden foreign body in their feet. Ten out of the 20 patients had positive ultrasound findings for a wooden foreign body. With the aid of the ultrasound study and preoperative markings, the subsequent mean surgical time was 20.8 minutes, with a 100% retrieval rate of the foreign body. Ultrasound was found to be 100% sensitive in the detection of wooden foreign bodies in the soft tissues of the foot. Ultrasonography should be considered an important diagnostic modality in the foot and ankle surgeon's armamentarium for the detection of retained wooden foreign bodies.