ECO2 framework assessment of limestone powder concrete slabs and columns

Producing limestone powder requires comparably far less energy than the production of ordinary Portland cement (OPC), making it a promising sustainable solution for partial replacement of OPC in concrete. Lower production energy could be translated into lower environmental impact and lower cost, which are two pillars of the sustainability of the resulting concrete. However, the question remains if replacing OPC with larger percentages of limestone powder would compromise the performance of the resulting concrete to a level that surpasses the environmental and economic gains. In order to assess the collective impact of these concretes, a performance-based multi-criteria decision analysis framework, ECO2, is used. For that purpose, 26 experimentally verified, concrete mixtures with and without limestone powder were evaluated through potential application in two types of reinforced concrete (RC) structural elements (slabs and columns) under identical environmental condition. The main results of the research showed a clear environmental advantage of concrete with a reduced OPC content, but the relatively higher superplasticizer amount in some cases could affect the final sustainability performance of the resulting mix. In the case of RC slabs, the best ECO2 score was obtained for concrete containing limestone powder. Mixtures with 200–250 kg of cement per unit volume of concrete had the highest ECO2 score for all the considered criteria. In the second case, due to the nature of the structural performance requirements in columns, the crucial influence of the concrete compressive strength is clear. The obtained results have shown approximately equal sustainability potential of OPC and limestone concretes in vertical elements such as columns. However, it seems that a certain improvement in the design of concrete mixtures with a high limestone powder content could make these competitive in all fields.This work was supported by the Ministry for Education, Science and Technology, Republic of Serbia [grant number TR36017].Peer ReviewedPostprint (published version

EMPIRICAL DETERMINATION OF THE FUNDAMENTAL PERIOD OF FREE VIBRATION OF RC BUILDINGS

Determining the value of the fundamental period of vibrations of reinforced concrete structures is a complex task. In order to have certain data on the fundamental period of vibration in the earliest design stage, engineers use various approximate methods, which can quickly and simply, but still sufficiently accurate, provide an estimate of the required parameter.The paper presents the most frequently used empirical expressions describing the dependence of the fundamental period in the function of the number of storeys, or the height of the building. All of these expressions, with greater or lesser accuracy, give an estimate of the required value, as shown by a number of examples. A graphic representation of all expressions and their comparison with experimental and numerically derived values has been performed

Dead-Time Correction for Nonparalyzing Detectors When Measuring Short-Lived Nuclides

The purpose of this article is to show that when the half-life of a specimen being measured is comparable to the dead time of the measurement system, an additional correction is required in the classical dead-time correction formula for a nonparalyzing detector. This additional correction accounts for the decay of radioactivity during the dead time, and therefore the expression for the additional correction includes the specimen half-life. This additional correction is significant for some specialized applications involving very short-lived nuclides. These results may be useful for neutron activation analysis of short-lived isotopes and certain medical imaging applications

Craterellus cornucopioides Edible Mushroom as Source of Biologically Active Compounds

© The Author(s) 2019 Article reuse guidelines: sagepub.com/journals-permissions Here we determined the phenolic compounds and antioxidant, antimicrobial, genotoxic, and anticancer potential of edible mushrooms Craterellus cornucopioides. The phytochemical analysis was evaluated using high-performance liquid chromatography. Antioxidant activity was evaluated by free radical scavenging, superoxide anion scavenging, and reducing power. Craterellus cornucopioides extract had potent antioxidant activity. Further, the antimicrobial potential was determined by a microdilution method, where minimum inhibitory concentration values ranged from 0.1 to 10 mg/mL. Genotoxic potential was determined by cytokinesis block micronucleus test. The separate treatment did not show genotoxic effect, whereas the combined treatment with mitomycin C significantly reduced the micronuclei frequency in a dose-dependent manner. The highest concentration significantly reduced nuclear division index in comparison to untreated human peripheral blood lymphocytes, whereas in combined treatment, the extract did not significantly affect this parameter. Finally, the cytotoxic activity was tested using microculture tetrazolium test where measured IC50 values ranged from 65.5 to 131.7 μg/mL

Polyphenolic contents of Teucrium polium L. and Teucrium scordium L. associated with their protective effects against MMC-induced chromosomal damage in cultured human peripheral blood lymphocytes

© TÜBİTAK. Teucrium species have been used in traditional medicine for treatment of different diseases. The aim of this study was to investigate polyphenolic contents by high-performance liquid chromatography (HPLC), and the genotoxic effect of methanolic extracts of Teucrium polium and Teucrium scordium using the cytokinesis-block micronucleus (CBMN) assay on human peripheral blood lymphocytes (PBLs) from healthy donors. The HPLC analysis showed that extracts consist of phenolic acid (gallic, vanillic, caffeic, chlorogenic, p-coumaric, sinapic) and flavonoids (catechin, rutin, myricetin, luteolin, quercetin and apigenin). Cultures were treated with extracts of both plants separately and in combinations with mitomycin C (MMC). In separate treatments, both herbal extracts significantly induced micronucleus (MN) frequency only at the highest concentrations. All concentrations of T. scordium, except the lowest, and all concentrations of T. polium extracts in combined treatment with MMC significantly reduced the frequency of MN. The extract of T. polium did not significantly affect the nuclear division index (NDI), whereas T. scordium in higher concentrations, separately and in combined treatment with MMC, significantly decreased the NDI value. Our results suggest that both herbal extracts in combination with MMC have antimutagenic (T. polium) and proapoptotic effects (T. scordium), which indicates their protective effects in PBLs

Investigation of biological activities and secondary metabolites of hydnum repandum acetone extract

© 2019, Romanian Society for Pharmaceutical Sciences. All rights reserved. This study aimed to evaluate the biological activities and polyphenolic contents of the acetone extract of H. repandum mushroom. Polyphenolic compounds were evaluated by high-performance liquid chromatography (HPLC). The antioxidant activity was assessed by radical scavenging activity assays and reducing power. The antimicrobial activity was established based on the values of the minimum inhibitory concentration (MIC) using microdilution method. Cytotoxic activity was determined by 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT). The genotoxic and antimutagenic activities were tested using cytokinesis block micronucleus (CBMN) assay on human peripheral blood lymphocytes in vitro. Among the determined polyphenolic compounds, ferulic acid and quercetin were mostly found. The extract showed high free radical scavenging activity, while the reducing power was less emphasized and concentration-dependent. The MIC fluctuated in a range of 0.009-10 mg/mL. The cytotoxic activity (based on IC50) ranged from 116.5 to 158.33 µg/mL, when HeLa cells were the most sensitive. The highest tested concentrations of the extract showed significant genotoxic activity, while against mitomycin C, the extract caused protective activity. The results indicated that H. repandum acetone extract contained secondary metabolites which showed biological activities such as antioxidant, antimicrobial, cytotoxic, genotoxic and protective against chemotherapeutics, indicating that their inclusion in nutrition could be of great importance in the prevention and treatment of various pathological conditions