New high-performance thyristor gate control set for line-commutatedconverters

In this paper, a novel implementation to obtain the triggering pulses for thyristorized AC/DC power converters is presented. The system developed is a variant of the digital ramp-and-threshold strategy employing parallel hardware calculation. In order to reduce the number of components otherwise involved, innovative ideas that make feasible the use of only one low-cost field-programmable gate array as the digital core, have been introduced. Based on the proposed topology, a compact high-resolution optimum-speed thyristor gate control circuit is achieved. The resulting system is very flexible and can be easily configured to drive series- or parallel-connected multiple-pulse controlled rectifiers. Practical results are provided     

The surgical risk of pancreas transplantation in the cyclosporine era: an overview

BACKGROUND: Pancreas transplants are still associated with the highest surgical complication rate of all routinely performed solid organ transplants. To date, the impact of serious surgical complications in the cyclosporine era on perioperative patient morbidity, graft and patient survival, and hospital costs has not been analyzed in detail. STUDY DESIGN: We retrospectively studied surgical complications after 445 consecutive pancreas transplants (45% simultaneous pancreas-kidney [SPK], 24% pancreas after kidney [PAK], and 31% pancreas transplant alone [PTA]). Of these, 80% were primary transplants, 20% were retransplants. Cadaver donors were used in 92%, living related donors in 8%. To develop guidelines for their prevention and management, we studied the impact of significant surgical complications (intra-abdominal infections, vascular graft thrombosis, and anastomotic leak) requiring relaparotomy on graft and patient survival. RESULTS: Relaparotomy was required after 32% of all pancreas transplants (SPK: 36%, PAK: 25%, PTA: 16% [p = 0.04]). Perioperative mortality was 9%. Graft and patient survival rates were significantly lower for recipients with (versus without) relaparotomy. The most common procedures were drainage of intra-abdominal abscess with graft necrosectomy (50% of all relaparotomies) and transplant pancreatectomy (34%). The most common causes of relaparotomy were intra-abdominal infection, vascular graft thrombosis, and anastomotic leak. Intra-abdominal infection occurred in 20% (SPK: 18%, PAK: 24%, PTA: 20% [p = NS]). The rate was significantly higher for living related donor (42%) versus cadaver donor (18%) recipients and for those with enteric-drained (39%) versus bladder-drained (18%) transplants. Graft and patient survival rates were significantly lower for recipients with (versus without) intra-abdominal infection. Outcome was better after bacterial (versus fungal) infections. For SPK recipients, those not on dialysis before the transplant had significantly higher graft survival than those on dialysis. Vascular graft thrombosis occurred in 12% of all recipients. The rate was significantly higher for PAK (21%) than for PTA (10%) and SPK (9%) recipients. It was significantly lower for recipients of grafts with donor iliac Y-graft reconstruction (versus all other types of arterial reconstruction) and with right-sided (versus left-sided) graft placement. Of note, patient survival was not different for recipients with versus without vascular graft thrombosis. The incidence of anastomotic or duodenal stump leaks was 10%; of these recipients, 70% required relaparotomy. Patient and graft survival rates were no different for recipients with versus without leaks. CONCLUSIONS: Serious surgical complications occurred in 35% of pancreas recipients and had a significant impact on patient and graft survival. Based on multivariate risk factor analyses, we recommend the following: donors over 45 years and those dying of cerebrocardiovascular disease should not be used; recipients over 45 years and those with a history of cardiac disease should be considered for a kidney transplant alone (KTA); surgical technique for graft procurement, preparation, and implantation should be meticulous; right-sided implantation and arterial Y-graft reconstruction should be performed when possible, since they had the highest success rates; when complications require relaparotomy, the focus must switch from graft salvage to life preservation; and the threshold for pancreatectomy should be low. Diagnosis should be timely, and treatment and relaparotomy expeditious. These cornerstones of success should help decrease the risk of surgical complications and mortality after pancreas transplants.     

Carbon FRP Strengthening of Doubly Curved Precast PC Shell

In this paper a recent rehabilitation project completed in Italy using carbon fiber reinforced plastic (CFRP) unidirectional sheets is examined. This technology was selected for the strengthening of a doubly curved, precast, prestressed concrete (PC) shell. The shell was part of the roof of an industrial building and had experienced severe localized damage due to accidental heat radiating from a flue. The selection of the CFRP system involved the screening of different repair procedures with relation to the constraints imposed by the owner: limited disturbance to the industrial process, safety of the occupants, low cost, and durability. In addition, the damaged PC shell was located in the center of the industrial building and did not allow the use of a crane for its replacement. This project demonstrates that the utilization of new materials can provide owners∕designers with effective solutions to challenging restoration problems.     

Synergistic antiproliferative activity of tamoxifen and docetaxel on three oestrogen receptor-negative cancer cell lines is mediated by the induction of apoptosis

The taxanes are a promising family of anti-tumour drugs that block cell cycle replication by interfering with the microtubule network. The clinical use of these drugs involves some problems related to their low solubility and occurrence of resistance, which is mainly dependent on the multidrug-resistant (MDR) phenotype. To investigate the possible interaction between docetaxel and tamoxifen (TAM), three oestrogen receptor-negative cancer cell lines, MDR- MDA-MB 231, MDR + CEM-VBLr and MCF-7 ADRr, were used. In all three cell lines, the combination of docetaxel and TAM was more effective in terms of growth inhibition than single drug exposure. Isobolic analysis confirmed the presence of synergism in all cell lines when docetaxel was used at 0.2 microM and TAM at a dose equal to or higher than 1 microM. Flow cytometric DNA analysis performed on the three cell lines showed that TAM was able to increase the G2/M blocking activity of docetaxel. This blocking activity was followed by an increased flow cytometric DNA fragmentation suggestive of the presence of apoptosis, which was confirmed by DNA gel fragmentation and morphological analysis. While an antagonistic effect on P-glycoprotein (P-gp) activity may contribute to the synergistic effect of tamoxifen and docetaxel on CEM-VBLr and MCF-7 ADRr, other mechanisms must be involved, as the synergistic effect is also apparent with a P-gp-negative cell line.     

Experimental validation of fully-adaptive smart antenna prototype

The architecture of a fully-adaptive smart antenna working in the 2.4 GHz band is described and its functionalities preliminarily assessed. The radiating unity consists of an eight-element linear array of dipoles with a finite reflecting plane. The adaptive behaviour is achieved by means of a set of electronically-driven vector modulators that realise the array weights. The capability to react in real-time to complex interference scenarios is provided by an SW control module based on the particle swarm optimiser (PSO) algorithm. To assess the effectiveness of such an implementation, a selected set of results is reported and discussed.     

Chronic pancreatitis prevalence in liver cirrhosis. Morphological and functional study

In the present study we have examined the ability of the beta-amyloid peptide (A beta(25-35)) to modulate the respiratory burst activity of human monocytes in vitro. Incubation of the cells for 24 h with A beta(25-35) as well as with A beta(1-42) resulted in an enhanced production of reactive oxygen radicals (ROI) in response to phorbol 12-myristate 13-acetate (PMA). Such effect was additively increased by coincubation with interferon-gamma (IFN gamma), and was paralleled by modulation of gene and protein expression of some components of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system. Since the effects of A beta(25-35) were also reproduced in primary rat microglia, our findings indicate that A beta(25-35) can potentiate the ability of mononuclear phagocytes to produce ROI, and add further insights into its biological effects.     

Effect of hydrogen charging on the stability of SAE 10B22 steel surface in alkaline solutions

The influence of hydrogen charging into a quenched and tempered boron steel membrane electrode (SAE 10B22) was studied using borate buffer (pH 8.4) and NaOH solutions (pH 12.7), with or without the addition of 0.01 M EDTA. At the hydrogen input side, hydrogen charging influenced cyclic voltammograms increasing the anodic charge of iron(II) hydroxide formation, and decreasing the donor density of passive films. These results suggest that the hydrogen ingress caused instability of metallic surface, increasing the surface area activity.     

Differential expression of a novel gene in response to coronatine, methyl jasmonate, and wounding in the Coi1 mutant of Arabidopsis

Coronatine is a phytotoxin produced by some plant-pathogenic bacteria. It has been shown that coronatine mimics the action of methyl jasmonate (MeJA) in plants. MeJA is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. In Arabidopsis thaliana, MeJA is essential for pollen grain development. The coi1 (for coronatine-insensitive) mutant of Arabidopsis, which is insensitive to coronatine and MeJA, produces sterile male flowers and shows an altered response to wounding. When the differential display technique was used, a message that was rapidly induced by coronatine in wild-type plants but not in coi1 was identified and the corresponding cDNA was cloned. The coronatine-induced gene ATHCOR1 (for A. thaliana coronatine-induced) is expressed in seedlings, mature leaves, flowers, and siliques but was not detected in roots. The expression of this gene was dramatically reduced in coi1 plants, indicating that COI1 affects its expression. ATHCOR1 was rapidly induced by MeJA and wounding in wild-type plants. The sequence of ATHCOR1 shows no strong homology to known proteins. However, the predicted polypeptide contains a conserved amino acid sequence present in several bacterial, animal, and plant hydrolases and includes a potential ATP/GTP-binding-site motif (P-loop).     

Use of an electrochemical method to evaluate the antioxidant activity of herb extracts from the Labiatae family

This paper describes a rapid method for the evaluation of the antioxidant activity of herb extracts from the Labiatae family. Herb methanolic extracts were analysed by using a flow injection (FI) system with an electrochemical detector equipped with a glassy carbon working electrode operating amperometrically at a potential of 0.5 V (vs. Ag/AgCl).     

Identification of HLA-unrestricted CD8+/CD28- cytotoxic T-cell clones specific for leukemic blasts in children with acute leukemia

We report on the identification of 57 T-cell clones (TCC) cytolytic to autologous leukemic blasts (LB) but not autologous bone marrow remission cells. LB-reactive TCC were obtained from 3 children with acute leukemia at remission; all expressed the same phenotype, CD3/TCR alpha beta/CD8+, but were heterogeneous for the expression of V beta T-cell receptor (TCR) V region chains, thus showing that these cells were not derived from the expansion of a single clone. Cytolytic activity of LB-reactive TCC was not restricted to autologous LB because they were also able to lyse phenotypically similar allogeneic LB but not bone marrow remission cells of the same patients. Neither autologous nor allogeneic LB used in the present study as stimulator and target cells expressed CD80 (B7/BB-1) antigen, and LB-reactive TCC were CD28-. Cytolytic activity of the clones was only inhibited by anti-CD11a (LFA-1) mAb but not by mAbs specific for HLA class I and II, CD3, CD8, or TCR alpha beta. In conclusion, these data suggest that a subset of apparently HLA-unrestricted, CD3/TCR alpha beta/CD8+ CD28- cytotoxic T lymphocytes, which use a TCR/CD3-independent recognition pathway, is primarily involved in antitumor immune response of children with acute leukemia at remission, possibly contributing to the control of minimal residual disease.