A new approach to the assessment of the reduction in visibility caused by fires of electrical cables

Electricity is the most important form of household energy and one of the most important forms of energy for industry and transport. Electrical distribution in construction and transport is almost exclusively implemented using electrical cables. One of the unresolved problems associated with electrical cables is the release of smoke and the resulting reduction of visibility in case of fire in the area. In this study, a new approach was developed to assess the reduction of visibility in an area affected by an electrical cable fire. This approach is based on the determination of the critical ratio of smoke volume (in the smoke layer and exhausted from the fire compartment) to the length of the burning cable, through which the visibility of reflective and illuminated signs was reduced to a lower limit value (a standard of 10 m). The input data for this approach was the extinction area of the smoke released from one meter of burning cable and the length of the cables in the area. This approach was used to test two power cables (CHKE-V J3x1.5 and CHKE-R J3x1.5) and one signal cable J-H(St)H 1 x 2 x 0.8 with the B2(ca), s1, d1, a1 fire reaction class. The smoke extinction area of the examined cables was determined using a cone calorimeter at a heat flux of 50 kW/m(2). The obtained data showed that in order to maintain a visibility of 10 m for reflective signs, the critical ratio of smoke volume to length of burning cable was 7.5 m(3)/m. For illuminated signs, the critical ratio was 2.8 m(3)/m. The relationship between burning length and visibility allows the calculation of visibility in the fire compartment affected by cable fire only from cables length.Web of Science53art. no. 4

Tunicamycin Depresses P-Glycoprotein Glycosylation Without an Effect on Its Membrane Localization and Drug Efflux Activity in L1210 Cells

P-glycoprotein (P-gp), also known as ABCB1, is a member of the ABC transporter family of proteins. P-gp is an ATP-dependent drug efflux pump that is localized to the plasma membrane of mammalian cells and confers multidrug resistance in neoplastic cells. P-gp is a 140-kDa polypeptide that is glycosylated to a final molecular weight of 170 kDa. Our experimental model used two variants of L1210 cells in which overexpression of P-gp was achieved: either by adaptation of parental cells (S) to vincristine (R) or by transfection with the human gene encoding P-gp (T). R and T cells were found to differ from S cells in transglycosylation reactions in our recent studies. The effects of tunicamycin on glycosylation, drug efflux activity and cellular localization of P-gp in R and T cells were examined in the present study. Treatment with tunicamycin caused less concentration-dependent cellular damage to R and T cells compared with S cells. Tunicamycin inhibited P-gp N-glycosylation in both of the P-gp-positive cells. However, tunicamycin treatment did not alter either the P-gp cellular localization to the plasma membrane or the P-gp transport activity. The present paper brings evidence that independently on the mode of P-gp expression (selection with drugs or transfection with a gene encoding P-gp) in L1210 cells, tunicamycin induces inhibition of N-glycosylation of this protein, without altering its function as plasma membrane drug efflux pump

The role of inherited genetic variants in colorectal polyposis syndromes

Colorectal carcinoma (CRC) is the third most common cancer in men and the second most common cancer in women across the world. Most CRCs occur sporadically, but in 15–35% of cases, hereditary factors are important. Some patients with an inherited predisposition to CRC will be diagnosed with a “genetic polyposis syndrome” such as familial adenomatous polyposis (FAP), MUTYH-associated polyposis (MAP), polymerase proofreading associated polyposis (PPAP), NTHL1-associated polyposis, MSH3-associated polyposis or a hamartomatous polyposis syndrome. Individuals with ≥ 10 colorectal polyps have traditionally been referred for genetic diagnostic testing to identify APC and MUTYH mutations which cause FAP and MAP respectively. Mutations are found in most patients with > 100 adenomas but in only a minority of those with 10–100 adenomas. The reasons that diagnostic laboratories are not identifying pathogenic variants include mutations occurring outside of the open reading frames of genes, individuals exhibiting generalized mosaicism and the involvement of additional genes. It is important to identify patients with an inherited polyposis syndrome, and to define the mutations causing their polyposis, so that the individuals and their relatives can be managed appropriately

The clerodane diterpene casearin J induces apoptosis of T-ALL cells through SERCA inhibition, oxidative stress, and interference with Notch1 signaling

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy that preferentially affects children and adolescents. Over 50% of human T-ALLs possess activating mutations of Notch1. The clerodane diterpene casearin J (CJ) is a natural product that inhibits the sarcoendoplasmatic reticulum calcium ATPase (SERCA) pump and induces cell death in leukemia cells, but the molecular mechanism of cytotoxicity remains poorly understood. Here we show that owing to SERCA pump inhibition, CJ induces depletion of the endoplasmic reticulum calcium pools, oxidative stress, and apoptosis via the intrinsic signaling pathway. Moreover, Notch1 signaling is reduced in T-ALL cells with auto-activating mutations in the HD-domain of Notch1, but not in cells that do not depend on Notch1 signaling. CJ also provoked a slight activation of NF-κB, and consistent with this notion a combined treatment of CJ and the NF-κB inhibitor parthenolide (Pt) led to a remarkable synergistic cell death in T-ALL cells. Altogether, our data support the concept that inhibition of the SERCA pump may be a novel strategy for the treatment of T-ALL with HD-domain-mutant Notch1 receptors and that additional treatment with the NF-κB inhibitor parthenolide may have further therapeutic benefits.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

CHOSEN VIEWS ON CABLE WITH IMPROVED FIRE PERFORMANCE

Currently, the fire protection of property and human health are an integral part of buildings security. We cannot neglect the reliability and long-term stability of cable systems which are important for safety, service and economic return on investment, too. For these purposes flame retardant and fire resistant cables are used in cable installation of buildings. Changes of dielectric properties may be related with modifications of insulation in order to limit smoke, fumes and halogens or improve their fire resistance. Manufacturers declare tests in compliance with valid standards. According to our experiences these tests need not verify real life time during operation or unexpected events such as flooding or current overload. The paper deals with application of cables with enhanced fire performance according to standards in Slovakia. The influence of the rated voltage during immersion in the water on insulation resistance and breakdown voltage of insulated cores with different flame barriers in the laboratory conditions are presented, too