Effect of interaction of two arbitrarily oriented cracks — Applications — Part II

The stress analysis for the problem of two arbitrarily oriented cracks is carried out in Part I. The problem is formulated using Kolossoff-Muskhelishvili's two complex stress function using the mapping technique and the Schwarz Alternative Method. As this is the most general geometry it has many particular cases. These cases are compared with the analytical solutions of other research workers such as Isida [10] in Part I, and Isida [5, 9], Gdoutos [6], Gupta et al. [7] and Viola [8] etc. in Part II. The present results are in good agreement with those of other research workers and the finite element method solutions used.Part I appears in International Journal of Fracture, Vol. 51, No. 3, pp. 219–230.Part I appears in International Journal of Fracture, Vol. 51, No. 3, pp. 219–230.     

In-vitro antioxidant and antibacterial activities of pumpkin,quince, muskmelon and bottle gourd seeds

Ethanol and chloroform extracts of pumpkin, quince, muskmelon, and bottle gourd seeds were studied for in-vitro antioxidant and antibacterial activities. Crude protein and fat contents of all the seeds compared favorably with high protein legumes and high oil containing oilseeds. Ethanol and chloroform extracts of bottle gourd seeds had highest phenolic content. A direct positive relationship between antioxidant activities and extract concentration was observed with the relationship being more pronounced in chloroform extract of quince seeds (R²?=?0.9685 and 0.9829) followed by ethanol extract of pumpkin seeds (R²?=?0.9666 and 0.9685) as per 1,1-diphenyl-2-picrylhydrazyl and hydrogen peroxide (H₂O₂) method, respectively. Seed extracts were also studied for in-vitro antibacterial activity against Salmonella typhii, Enterococcus sp., Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Ethanol extract of pumpkin seeds inhibited the growth of all bacteria; however, both the extracts of quince seeds did not show any activity against S. typhii, E. coli and S. aureus.     

Role of P-selectin cytoplasmic domain in granular targeting in vivo and in early inflammatory responses

P-selectin is an adhesion receptor for leukocytes expressed on activated platelets and endothelial cells. The cytoplasmic domain of P-selectin was shown in vitro to contain signals required for both the sorting of this protein into storage granules and its internalization from the plasma membrane. To evaluate in vivo the role of the regulated secretion of P-selectin, we have generated a mouse that expresses P-selectin lacking the cytoplasmic domain (DeltaCT mice). The deletion did not affect the sorting of P-selectin into alpha-granules of platelets but severely compromised the storage of P-selectin in endothelial cells. Unstored P-selectin was proteolytically shed from the plasma membrane, resulting in increased levels of soluble P-selectin in the plasma. The DeltaCT-P-selectin appeared capable of mediating cell adhesion as it supported leukocyte rolling in the mutant mice. However, a secretagogue failed to upregulate leukocyte rolling in the DeltaCT mice, indicating an absence of a releasable storage pool of P-selectin in the endothelium. Furthermore, the neutrophil influx into the inflamed peritoneum was only 30% of the wild-type level 2 h after stimulation. Our results suggest that different sorting mechanisms for P-selectin are used in platelets and endothelial cells and that the storage pool of P-selectin in endothelial cells is functionally important during early stages of inflammation.     

Outcome of obstructive uropathy after pelvic irradiation in patients with carcinoma of the uterine cervix

A prospective, randomized study was performed to assess the effectiveness of postoperative closed suction drainage. One hundred and twelve consecutive procedures involving autologous iliac-crest bone graft were performed, from December 29, 1992, to July 1, 1993, following a traumatic injury of the spine in 108 patients. Sixty of the sites from which the bone graft had been obtained were drained with a single large Hemovac device. The drains were maintained for two to five days postoperatively. The remaining fifty-two incisions were closed without a drainage device. All patients were evaluated clinically for problems with wound-healing. The incisions were considered to be healed when they had been asymptomatic for one year. Of eleven patients who had problems with wound-healing, six had been managed with a drain and five had not. The findings of this study do not support the routine use of drainage at the donor sites of iliac-crest bone grafts.     

Antibodies to bacterial antigens and autoantigens in pregnant women with kidney diseases

The levels of antibodies (Ab) to bacterial antigens of gram-negative enterobacteria (Reglicolipid), Streptococcus agalactiae polysaccharide, Staphylococcus aureus teichoic acid, native and denatured DNA and renal proteins in healthy pregnant women and in those with renal pathology (chronic and gestation pyelonephritis) were studied. The study revealed that the combination of an elevated levels of Ab to bacterial antigens with the elevated titers of Ab to DNA and renal proteins is indicative of acute inflammation in kidneys, and but the combination of an elevated levels of Ab bacterial antigens with the low level of Ab to DNA and renal proteins is indicative of healthy carrier state with respect to a given infective agent.     

Differential response of cortical plate and ventricular zone cells to GABA as a migration stimulus

A microdissection technique was used to separate differentiated cortical plate (cp) cells from immature ventricular zone cells (vz) in the rat embryonic cortex. The cp population contained >85% neurons (TUJ1(+)), whereas the vz population contained approximately 60% precursors (nestin+ only). The chemotropic response of each population was analyzed in vitro, using an established microchemotaxis assay. Micromolar GABA (1-5 microM) stimulated the motility of cp neurons expressing glutamic acid decarboxylase (GAD), the rate-limiting enzyme in GABA synthesis. In contrast, femtomolar GABA (500 fM) directed a subset of GAD- vz neurons to migrate. Thus, the two GABA concentrations evoked the motility of phenotypically distinct populations derived from different anatomical regions. Pertussis toxin (PTX) blocked GABA-induced migration, indicating that chemotropic signals involve G-protein activation. Depolarization by micromolar muscimol, elevated [K+]o, or micromolar glutamate arrested migration to GABA or GABA mimetics, indicating that migration is inhibited in the presence of excitatory stimuli. These results suggest that GABA, a single ligand, can promote motility via G-protein activation and arrest attractant-induced migration via GABAA receptor-mediated depolarization.