Long-term performance of novel high-calcium one-part alkali-activated cement developed from thermally activated lime kiln dust

The traditional activation approach for alkali-activated cement AAC has several problems resulting mainly from the hazardous and corrosiveness of the alkaline chemicals, such as (NaOH, Na2SiO3), which in turn impede the utilisation of AAC in the construction fields. In this study, A second generation of alkali activated binder was developed using Metakaolin (MK) and natural pozzolan material (NP) (as a source of alumina-silicate), these materials were activated using high-calcium lime kiln dust as solid activator to transform the alumina-silicate crystalline phases to cementitious hydrated products. This was achieved with the aid of heat treatment of materials at different temperatures. Raw materials and final AAC samples were characterised using analytical methods, such X-Ray powder diffraction (XRD), Thermogravimetric Analysis (TG-DTA), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Additionally, long-term compressive strength, chemical and microstructural performance were investigated. The transformation of raw materials from crystalline to amorphous phases happened due to the effect of the heat treatment and the formation of stratlingite products in the final AAC paste, which were evidenced using the mentioned characterisation methods. The findings of the present study proved that the compressive strength of the new binder reached 27 MPa and 51 MPa after 28 and 180 days of curing, respectively, ensuring a progressive as well as a higher degree of alkali-activation and disappearance of unreacted alkaline substances in the final AAC products

Developing One-Part Alkali-Activated metakaolin/natural pozzolan Binders using Lime Waste as activation Agent

Among the several schemes that have been reported to be a satisfactory alternative to Portland cement is Alkali Activated Cement (AAC), which has recently started to gain greater consideration in construction sectors. Conventional two-part alkali activation has many drawbacks, including the activating solution being viscous, problematic and non-user friendly to handle. Thus, this research aims to produce a one-part alkali activated metakaolin/natural pozzolan, by using an earth alkaline source (rich in CaO) from waste material (lime kiln dust), as an activating precursor to break the alumina-silicate crystalline phases. Thermal treatment of materials at two levels of treatment (450°C and 950°C), was used as an assisted activation approach. Analytical techniques including X-Ray powder diffraction XRD, Thermogravimetric Analysis TG-DTA, Fourier Transform Infrared Spectroscopy FTIR and Scanning Electron Microscope SEM, were utilised to investigate the performance of the developed materials at a molecular level. Reduction of crystalline peaks as well as the appearance of new wollastonite minerals within the calcined lime kiln dust, contributed to the development of 27 MPa compressive strength after 28 days. The dissolution made through the pozzolanic reaction as well as thermal treatment evidently contributed to transform crystalline to amorphous phases

Texture-Based Analysis of Fetal Organs in Fetal Growth Restriction

Fetal growth restriction (FGR) is common, affecting around 10% of all pregnancies. Growth restricted fetuses fail to achieve their genetically predetermined size and often weigh <10th centile for gestation. However, even appropriately grown fetuses can be affected, with the diagnosis of FGR missed before birth. Babies with FGR have a higher rate of stillbirth, neonatal morbidity such as breathing problems, and neurodevelopmental delay. FGR is usually due to placental insufficiency leading to poor placental perfusion and fetal hypoxia. MRI is increasingly used to image the fetus and placenta. Here we explore the use of novel multi-compartment Intravoxel Incoherent Motion Model (IVIM)-based models for MRI fetal and placental analysis, to improve understanding of FGR and quantify abnormalities and biomarkers in fetal organs. In 12 normally grown and 12 FGR gestational-age matched pregnancies (Median 28+ 4 wks±3+ 3 wks) we acquired T2 relaxometry and diffusion MRI datasets. Decreased perfusion, pseudo-diffusion coefficient, and fetal blood T2 values in the placenta and fetal liver were significant features distinguishing between FGR and normal controls (p-value <0.05). This may be related to the preferential shunting of fetal blood away from the fetal liver to the fetal brain that occurs in placental insufficiency. These features were used to predict FGR diagnosis and gestational age at delivery using simple machine learning models. Texture analysis was explored to compare Haralick features between control and FGR fetuses, with the placenta and liver yielding the most significant differences between the groups. This project provides insights into the effect of FGR on fetal organs emphasizing the significant impact on the fetal liver and placenta, and the potential of an automated approach to diagnosis by leveraging simple machine learning models

The Role of Embodied Carbon in Sustainable Construction: A Review of Qatar's Practices and Perspectives

This study explores the urgent need for an embodied carbon (EC) assessment framework within Qatar's construction sector, driven by the country's rapid development and high carbon intensity in construction materials, such as cement and steel. Employing a systematic literature review through the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) methodology and Visualization of Similarities (VOS) viewer for bibliometric analysis, this study identifies major gaps in Qatar-specific EC data and regulation. It highlights global best practices, particularly those from countries with mandated EC regulations, and discusses their potential adaptation to Qatar's unique environmental and economic context. This study advocates the establishment of a comprehensive EC database to inform construction practices aligned with Qatar's sustainability goals under its National Vision 2030. The findings suggest that a regionally adapted EC framework would significantly aid Qatar in reducing greenhouse gas emissions, given the country's heavy reliance on energy-intensive materials and its extreme climate. The study concludes with recommendations for the policy integration of EC assessments in Qatar's building sector, aiming to support sustainable urban development and climate resilience in the face of intensifying environmental challenges

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Super-resolution Reconstruction MRI Application in Fetal Neck Masses and Congenital High Airway Obstruction Syndrome

OBJECTIVE: Reliable airway patency diagnosis in fetal tracheolaryngeal obstruction is crucial to select and plan ex utero intrapartum treatment (EXIT) surgery. We compared the clinical utility of magnetic resonance imaging (MRI) super-resolution reconstruction (SRR) of the trachea, which can mitigate unpredictable fetal motion effects, with standard 2-dimensional (2D) MRI for airway patency diagnosis and assessment of fetal neck mass anatomy. STUDY DESIGN: A single-center case series of 7 consecutive singleton pregnancies with complex upper airway obstruction (2013-2019). SETTINGS: A tertiary fetal medicine unit performing EXIT surgery. METHODS: MRI SRR of the trachea was performed involving rigid motion correction of acquired 2D MRI slices combined with robust outlier detection to reconstruct an isotropic high-resolution volume. SRR, 2D MRI, and paired data were blindly assessed by 3 radiologists in 3 experimental rounds. RESULTS: Airway patency was correctly diagnosed in 4 of 7 cases (57%) with 2D MRI as compared with 2 of 7 cases (29%) with SRR alone or paired 2D MRI and SRR. Radiologists were more confident (P = .026) in airway patency diagnosis when using 2D MRI than SRR. Anatomic clarity was higher with SRR (P = .027) or paired data (P = .041) in comparison with 2D MRI alone. Radiologists detected further anatomic details by using paired images versus 2D MRI alone (P < .001). Cognitive load, as assessed by the NASA Task Load Index, was increased with paired or SRR data in comparison with 2D MRI. CONCLUSION: The addition of SRR to 2D MRI does not increase fetal airway patency diagnostic accuracy but does provide improved anatomic information, which may benefit surgical planning of EXIT procedures

The need for national medical licensing examination in Saudi Arabia

<p>Abstract</p> <p>Background</p> <p>Medical education in Saudi Arabia is facing multiple challenges, including the rapid increase in the number of medical schools over a short period of time, the influx of foreign medical graduates to work in Saudi Arabia, the award of scholarships to hundreds of students to study medicine in various countries, and the absence of published national guidelines for minimal acceptable competencies of a medical graduate.</p> <p>Discussion</p> <p>We are arguing for the need for a Saudi national medical licensing examination that consists of two parts: Part I (Written) which tests the basic science and clinical knowledge and Part II (Objective Structured Clinical Examination) which tests the clinical skills and attitudes. We propose this examination to be mandated as a licensure requirement for practicing medicine in Saudi Arabia.</p> <p>Conclusion</p> <p>The driving and hindering forces as well as the strengths and weaknesses of implementing the licensing examination are discussed in details in this debate.</p

Investigating the Willingness to Pay for a Contributory National Health Insurance Scheme in Saudi Arabia:A Cross-sectional Stated Preference Approach

Background: The Saudi Healthcare System is universal, financed entirely from government revenue principally derived from oil, and is ‘free at the point of delivery’ (non-contributory). However, this system is unlikely to be sustainable in the medium to long term. This study investigates the feasibility and acceptability of healthcare financing reform by examining households’ willingness to pay (WTP) for a contributory national health insurance scheme. Methods: Using the contingent valuation method, a pre-tested interviewer-administered questionnaire was used to collect data from 1187 heads of household in Jeddah province over a 5-month period. Multi-stage sampling was employed to select the study sample. Using a double-bounded dichotomous choice with the follow-up elicitation method, respondents were asked to state their WTP for a hypothetical contributory national health insurance scheme. Tobit regression analysis was used to examine the factors associated with WTP and assess the construct validity of elicited WTP. Results: Over two-thirds (69.6%) indicated that they were willing to participate in and pay for a contributory national health insurance scheme. The mean WTP was 50 Saudi Riyal (US$13.33) per household member per month. Tobit regression analysis showed that household size, satisfaction with the quality of public healthcare services, perceptions about financing healthcare, education and income were the main determinants of WTP. Conclusions: This study demonstrates a theoretically valid WTP for a contributory national health insurance scheme by Saudi people. The research shows that willingness to participate in and pay for a contributory national health insurance scheme depends on participant characteristics. Identifying and understanding the main influencing factors associated with WTP are important to help facilitate establishing and implementing the national health insurance scheme. The results could assist policy-makers to develop and set insurance premiums, thus providing an additional source of healthcare financing

Reply to commentary by R Duggleby (2019)

Duggleby (2018) has made a numerical analysis of some aspects of the wide range of phenomena we reviewed in Steele et al. (2018) and asserted " .that panspermia as proposed by Steele et al. (2018) is extremely implausible.” It seems to us that Duggleby has based his viewpoint on a quite narrow and specific model of Panspermia which he supposes to be active in the cosmos. Here we address both his conclusions and his numerical analysis. Our response therefore will be at two levels, his specific analysis and his general conclusions. In the specific section below we show that while Duggleby's numerical analysis appears in part correct it is, in the final analysis, quite irrelevant to Cosmic Panspermia. In the general response which follows we address his unsupported conclusion throughout his critique, namely that … " none of the examples mentioned by Steele et al. (2018) is decisive enough to allow no other explanation.