Effect of temperature on early-age properties of self-consolidating concrete equivalent mortar

ACLIn this study, the effect of material temperature during casting on fresh properties, hydration kinetics, and early-age compressive strength of self-consolidating concrete (SCC) was evaluated. Concrete equivalent mortars (CEMs) based on SCC mixture designs with water-to-binder ratios of 0.41 and 0.45 were investigated. The SCC mixtures are targeted for infrastructure and building construction and precast applications. The CEMs were prepared at temperatures ranging from 8 to 36°C. Superplasticizer (SP) and air-entraining agent (AEA) demand were evaluated for the CEM mixtures made with different supplementary cementing material (SCM) and limestone filler types. Test results showed that the ambient temperature can significantly affect the SP and AEA demand, hydration kinetics, and compressive strength after 1 d of age. According to the ultraviolet–visible spectrophotometry (UV/Vis) test, the absorption rate of polycarboxylate-based SP decreased with temperature. In contrast, the sensitivity of polynaphthalene sulfonate-based SP to temperature was minimal. Relationships between the variations of different admixture contents, heat flux, and compressive strength with temperature were developed. For a constant slump flow and air content, the demand of the SP and AEA, heat flux, and 1-d compressive strength of CEMs increased linearly with material temperature

Microsatellite Instability in Young Women with Endometrioid type Endometrial Cancer

"nBackground: This study was designed to determine the frequency of Microsatellite Instability (MSI) in young Iranian pa­tients with endometrial carcinoma and to evaluate its association with histopathologic and clinical features of disease."nMethods: Microsatellite status was analyzed in 23 patients with endometrioid type endometrial cancer who were less than 55 years. Clinicopathologic characteristics such as age, International Federation of Gynecology and Obstetric (FIGO) grad­ing and staging of tumor, family history of Hereditary Non-polyposis Colorectal Cancer (HNPCC), oral conception (OC) consump­tion, number of pregnancies, fertility, menstrual cycles and underlying disease were considered. Chi-square and Fisher exact tests were used to find the significant relationships."nResults: MSI analysis showed 8 patients (34.8%) were MSS (Microsatellite Stable), 15 patients (62.5%) were MSI positive. Among cases with MSI phenotype, 4 cases (17.4%) had low instability (MSI-L) and 11 cases (47.8%) had high instability (MSI-H). Three cases with MSI-H had family history of HNPCC related cancers. Five cases (21.7%) had infertility in which 4 of them (80%) had MSI phenotype. There was no statistically significant relationship between MSI phenotype and tumor grade and stage."nConclusion: Few studies reported high frequency of MSI among young patients. Some studies mentioned similar results in endo­metrioid type of tumor. This study showed even higher frequency (65%) when MSI analyzed in young endometrioid type endometrial patients. Most cases with infertility had MSI-H phenotype. It may suggest that beside women with family his­tory of HNPCC, EC screening using MSI would be beneficial in infertile women too. &nbsp

Effect of nanoclay on durability and mechanical properties of flax fabric reinforced geopolymer composites

The main concern of using natural fibres as reinforcement in geopolymer composites is the durability of the fibres. Geopolymers are alkaline in nature because of the alkaline solution that is required for activating the geopolymer reaction. The alkalinity of the matrix, however, is the key reason of the degradation of natural fibres. The purpose of this study is to determine the effect of nanoclay (NC) loading on the mechanical properties and durability of flax fabric (FF) reinforced geopolymer composites. The durability of composites after 4 and 32 weeks at ambient temperature is presented. The microstructure of geopolymer matrices was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the incorporation of NC has a positive impact on the physical properties, mechanical performance, and durability of FF reinforced geopolymer composites. The presence of NC has a positive impact through accelerating the geopolymerization, reducing the alkalinity of the system and increasing the geopolymer gel. © 2017 The Ceramic Society of Japan and the Korean Ceramic Society