Persistence of frequency in gas–liquid flows across a change in pipe diameter or orientation

From a study of the characteristics of structures across a 67/38 mm sudden contraction, using air/silicone oil flows, it has been found that frequencies of the structures (mainly slugs) persist across the contraction. This is in contrast to the velocities and lengths which increase as they move into the smaller diameter pipe. These observations were found for both vertical and 5° upward orientations. A similar persistence of frequency has been found from four other sources in the literature: a vertical (gradual) contraction; a horizontal Venturi; and two cases of horizontal pipe, 90° bend and vertical riser combination. The latter were at two contrasting conditions: (i) at atmospheric pressure with air/water in small diameter (34 mm) pipes; (ii) at 20 bar in larger diameter pipes (189 mm) using nitrogen and naphtha

A preclinical evaluation of alternative site for islet allotransplantation

<div><p>The bone marrow cavity (BMC) has recently been identified as an alternative site to the liver for islet transplantation. This study aimed to compare the BMC with the liver as an islet allotransplantation site in diabetic monkeys. Diabetes was induced in Rhesus monkeys using streptozocin, and the monkeys were then divided into the following three groups: Group1 (islets transplanted in the liver with immunosuppressant), Group 2 (islets transplanted in the tibial BMC), and Group 3 (islets transplanted in the tibial BMC with immunosuppressant). The C-peptide and blood glucose levels were preoperatively measured. An intravenous glucose tolerance test (IVGTT) was conducted to assess graft function, and complete blood cell counts were performed to assess cell population changes. Cytokine expression was measured using an enzyme-linked immune sorbent assay (ELISA) and MILLIPLEX. Five monkeys in Group 3 exhibited a significantly increased insulin-independent time compared with the other groups (Group 1: 78.2 ± 19.0 days; Group 2: 58.8 ± 17.0 days; Group 3: 189.6 ± 26.2 days) and demonstrated increases in plasma C-peptide 4 months after transplantation. The infusion procedure was not associated with adverse effects. Functional islets in the BMC were observed 225 days after transplantation using the dithizone (DTZ) and insulin/glucagon stains. Our results showed that allogeneic islets transplanted in the BMC of diabetic Rhesus monkeys remained alive and functional for a longer time than those transplanted in the liver. This study was the first successful demonstration of allogeneic islet engraftment in the BMC of non-human primates (NHPs).</p></div

BcR-induced apoptosis involves differential regulation of C-16 and C-24-ceramide formation and sphingolipid-dependent activation of the proteasome

In this study, we describe an ordered formation of long- and very long-chain ceramide species in relation to the progression of B-cell receptor (BcR) triggering induced apoptosis. An early and caspase-independent increase in long-chain ceramide species, in which C-24-ceramide predominated, was observed 6 h after Belt triggering. In contrast, very long-chain ceramide species were generated later, 12-24 h after BeR triggering. The formation of these very long-chain ceramide species, in which C-24-ceramide predominated, required the activation of effector caspases. BcR-induced formation of long-chain ceramide species resulted in proteasomal activation and degradation of XIAP and subsequent activation of effector caspases, demonstrating an important cell-biological mechanism through which longchain ceramides may be involved in the progression of BcR triggering induced apoptosis and subsequent formation of very long-chain ceramide species. BcR-induced activation of the proteasome was blocked with ISP-1/myriocin, a potent and selective inhibitor of serine palmitoyl transferase that catalyzes the first and rate-limiting step in the de novo formation of ceramide. Both ISP-1 and clasto-lactacystin beta-lactone, an irreversible inhibitor of the proteasome, prevented BcR cross-linking-induced XIAP degradation. Also, a mutant XIAP lacking the ubiquitin-ligating ring finger motif was completely resistant to proteasome-mediated degradation, and Ramos cells overexpressing XIAP became highly resistant to BcR cross-linking-induced activation of caspases. The formation of C-16-ceramide in response to BcR cross-linking was found unaltered in XIAP overexpressing Ramos cells, whereas C-24-ceramide formation was completely abolished. These results demonstrate how de novo generated long-chain ceramide species may be involved in the activation of downstream effector caspases and subsequent formation of very long-chain ceramide species. As such, these results provide novel and important insights into the significance of specific ceramide species in defined stages of apoptosis