Flow and heat-transfer in an internally-heated, naturally-ventilated space

This paper presents the findings of a theoretical and experimental investigation of the thermodynamics of an internally-heated control volume (CV), ventilated by natural convection. A simple bench-type experiment has been used to determine the temperature history of the air, in support of a global calculation by numerical methods. Good agreement has been achieved between the experimental results and the mathematical prediction, which has wide ranging applications in practical situations.     

Mechanism of the diabetogenic action of cyclosporin A

To investigate the mechanism of diabetogenic action of cyclosporin A (CsA), 7 male Wistar albino rats received 10 mg/kg/day of the drug for 4 weeks (CsA). The results were compared with controls (C); blood CsA levels measured weekly remained stable throughout the experiment (mean +/- SEM) (X = 2657.9+/-155.1 ng/ml). Intravenous glucose load (0.75 g/kg) performed after 2 weeks of CsA therapy showed glucose intolerance in treated animals as evaluated by the glucose area under the curve (CsA = 409.2+/-17.8 vs. C = 313.3+/-12.6 umol x ml(-1) x min(-1)) (p < 0.05) with insulin levels being similar in the two groups (CsA = 8603.9+/-1645.5 vs. C = 9571.9+/-828.5 pmol x ml(-1) x min(-1)). After 4 weeks of CsA administration, glucose intolerance was maintained (CsA = 398.6+/-35.6 vs. C = 301.7+/-23.0 umol x ml(-1) x min(-1)) (p < 0.05) associated with a significant decrease in insulin secretion (CsA = 4404.9+/-2392.0 vs. C = 10075.9+/-2861.0 pmol x ml(-1) x min(-1) (p < 0.05). These results suggest that CsA induced a state of insulin resistance preceding the failure of insulin secretion. After 4 weeks, the pancreatic insulin content was also decreased (CsA = 0.7+/-0.1 vs. C = 1.4+/-0.5 mU/mg) (p < 0.05). Maximal insulin binding to isolated adipocytes was not affected by CsA (CsA = 7.4+/-2.6 vs. C = 6.4+/-2.0%), although glucose transport and oxidation decreased after CsA treatment (p < 0.05). In conclusion, glucose intolerance induced by CsA in Wistar albino rats is due to decreased insulin production and impaired insulin action by a post-binding mechanism.     

bcl-2 alters the antigen-driven selection of B cells in mukappa but not in mu-only Xid transgenic mice

A point mutation in the pleckstrin homology domain of the mouse Bruton's tyrosine kinase (btk) gene results in an X-linked immune defect, Xid, characterized by immunologic unresponsiveness to polymeric carbohydrate Ags. In Xid mice, B cells specific for phosphocholine (PC) do not develop in peripheral lymphoid tissues because they either fail to be positively selected from the marrow or they are clonally deleted via an Ag-driven, receptor-mediated process. Overexpression of the bcl-2 gene allows PC-specific B cells to survive and mature in Xid mukappa anti-PC transgenic mice, but PC-specific B cells are not rescued by bcl-2 in Xid mu-only transgenic mice. The failure of bcl-2 to rescue PC-specific B cells, in mu-only transgenic mice suggests that either it does not correct the btk defect in the Ag-driven selection process that occurs in pre-B cells and/or in very immature B cells or that a btk-dependent proliferative phase is required for the selection and amplification of the PC-specific B cells in mu-only transgenic mice. The rescue of PC-specific B cells in mukappa transgenic mice indicates that bcl-2 can alter receptor-mediated B cell selection at late stages in B cell development. The rescued PC-specific B cells in Xid male mice do not exhibit an altered proliferation profile in response to B cell-stimulating agents compared with B cells from unmanipulated Xid mice; thus, they fail to respond to soluble anti-mu, or PC-dextran, but they proliferate in response to PC, anti-mu, or anti-id conjugated to Sepharose.     

Prospective, multicenter study of laparoscopic ventral hernioplasty. Preliminary results

BACKGROUND: A standard technique for laparoscopic ventral hernioplasty (peritoneal onlay using an expanded polytetrafluoroethylene [ePTFE] patch for hernias >/=4 cm2) is being used in a prospective, multicenter, long-term study. METHODS: Demographic, operative, and postoperative data were collected and analyzed. Follow-up clinical evaluations were conducted 7-10 days, 4 weeks, 6 months, 1 year, and then annually after surgery in all patients. RESULTS: In the first 2 years of the study, 144 patients were enrolled; nine were lost to follow-up. The mean operating time was 120 min. The mean follow-up was 222 days (range 5-731). Postoperative complications were five infections, three cases of prolonged ileus, one bowel obstruction, 23 seromas (15 resolved without intervention), and six hernia recurrences. Hospital discharge occurred a mean of 2.3 days after surgery and return to normal activity a mean of 15 days postoperatively. CONCLUSIONS: Laparoscopic prosthetic ventral hernioplasty avoids the large wound required in open repairs, with attendant complications and recurrences, and appears safe, especially if an ePTFE mesh is used. Compared with conventional open ventral hernioplasty, the laparoscopic technique may also allow shorter hospitalization and a quicker return to normal activities after surgery.     

Influence of sample treatment on ESR signal of irradiated citrus

ESR spectra of the hard seed cover and kernel coating of irradiated orange and tangerine fruits were obtained under different sample drying conditions to analyze the effect of treatment on ESR line at g = 2.0033 (line A). The spectra shows almost the same lines that appear in stalks, achenes, seeds and skins of fresh fruit. The peak-to-peak intensity of the line A of the spectra shows a linear variation with dose in the range studied (up to 5 kGy) under controlled sample preparation. Q-band ESR spectra shows that this line is composed for three different lines from different species. A1, A2 and A3. The A2 and A3 lines are associated with dose but grow also during drying of the sample and are probably due to 'cellulosic' components of the seed cover. The A1 line appears only when sample is dried and is probably associated with the quinones of the internal kernel coat.