An experimental study on the thermal characteristics and heating effect of arc-fault from Cu core in residential electrical wiring fires.

The characteristics of a series direct current (DC) arc-fault including both electrical and thermal parameters were investigated based on an arc-fault simulator to provide references for multi-parameter electrical fire detection method. Tests on arc fault behavior with three different initial circuit voltages, resistances and arc gaps were conducted, respectively. The influences of circuit conditions on arc dynamic image, voltage, current or power were interpreted. Also, the temperature rises of electrode surface and ambient air were studied. The results showed that, first, significant variations of arc structure and light emitting were observed under different conditions. A thin outer burning layer of vapor generated from electrodes with orange light was found due to the extremely high arc temperature. Second, with the increasing electrode gap in discharging, the arc power was shown to have a non monotonic relationship with arc length for constant initial circuit voltage and resistance. Finally, the temperature rises of electrode surface caused by heat transfer from arc were found to be not sensitive with increasing arc length due to special heat transfer mechanism. In addition, temperature of ambient air showed a large gradient in radial direction of arc.

Aminobenzoic acid hydrazide, a myeloperoxidase inhibitor, alters the adhesive properties of neutrophils isolated from acute myocardial infarction patients.

Acute myocardial infarction (AMI) is associated with vascular inflammation, including activation and adherence of neutrophils to vascular endothelial cells via CD11b/CD18 intercellular adhesion molecule interactions. Myeloperoxidase (MPO) induces CD11b surface expression in polymorphonuclear neutrophils (PMNs); however, its role in regulating adhesion in AMI is not well characterized. This study investigates the effects of aminobenzoic acid hydrazide (ABAH), an inhibitor of MPO, antibodies specific for CD11b, on the adhesion of PMNs isolated from AMI patients to endothelial cells. Human neutrophils were isolated from the peripheral blood of 20 patients with AMI or 20 healthy participants as control using Percoll density gradient centrifugation. The major biochemical indicators were detected with different biochemical analyses. The effects of ABAH and anti-CD11b antibodies on neutrophil adhesion to endothelial cell were measured using adhesion assays in vitro. The adhesion rate was significantly higher for neutrophils isolated from AMI patients than healthy individuals (P < 0.001). ABAH significantly inhibited MPO activity in PMNs isolated from AMI patients. Neutrophil adhesion was significantly reduced upon treatment with 10 and 20 µM ABAH in a dose-dependent manner. Treatment with anti-CD11b antibodies also significantly reduced neutrophil adhesion in comparison with the untreated control group (P < 0.001). Thus, both ABAH and anti-CD11b antibodies reduced PMN adhesion. Further studies are necessary to determine whether MPO enhances neutrophil adhesion to endothelial cells in AMI patients through the upregulation of CD11b expression on the surface of neutrophils, which is abrogated by ABAH.

Assessment of ischemia-modified albumin levels for emergency room diagnosis of acute coronary syndrome.

BACKGROUND: The aim of this study was to retrospectively evaluate the utility of assessing ischemia-modified albumin (IMA) levels for diagnosing acute coronary syndrome (ACS) in patients presenting to the emergency room (ER) with chest pain. METHODS: The records of patients admitted to the ER with chest pain between August 2006 and December 2008 were examined. Those subsequently diagnosed with ACS were included in the study. Serum IMA and cardiac troponin I (cTnI) concentrations were determined in blood samples obtained from patients within 3h of ER admission and on days 1, 3, 7 and 14. IMA and cTnI cut-off values for diagnosis of ACS were employed and the successful diagnosis rates were compared. RESULTS: Of the patients diagnosed with ACS following ER presentation with acute chest pain, the correct diagnosis rate was significantly higher as determined by assessment of IMA vs. cTnI concentrations within 3h of ER presentation (81.02% vs. 42.34%, P<0.01). Thereafter there were no between marker differences in rates of successful diagnosis. CONCLUSIONS: These findings support the notion that IMA may be a useful biochemical marker for the early diagnosis of ACS, particularly in patients presenting to the ER with acute chest pain.