Effect of rice husk ash properties on the early age and long term strength of mortar

This paper presents an experimental study on the effect of chemical composition and physical properties of rice husk ash (RHA) on the strength of mortar. The aim of this investigation was to establish the optimal RHA replacement levels as blending component in cement. Four different types of RHA (A, B, C and D) were used of which RHA-C and D had the highest content of amorphous silica. Compressive and tensile strength and workability of the mixes were compared with control OPC samples. Results show that the early age (7days) strength of RHA blended mortar samples was lower than the compressive and tensile strength of the OPC control samples. However, the 28 day strength of samples with up to 20% RHA-C and RHA- D was higher than that of the control samples. The 90 day strength of all blended samples with up to 40% RHA was higher than that of the control samples. RHA-D performed best in the experiments with a compressive strength increase of 16% at 20% RHA replacement and an increase of compressive strength of 8.6% at 40% RHA replacement. The results at 90 days show that cement could be replaced with up to 50% RHA with only a small reduction in strength compared to OPC mortar. From the results it was found that the content of amorphous silica has the biggest influence on the strength of the mortar samples while the workability was higher for samples with finer grained RHA

Room temperature mid-IR single photon spectral imaging

Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are emerging as an enabling technology of great technical and scientific interest; primarily because important chemical compounds display unique and strong mid-IR spectral fingerprints revealing valuable chemical information. While modern Quantum cascade lasers have evolved as ideal coherent mid-IR excitation sources, simple, low noise, room temperature detectors and imaging systems still lag behind. We address this need presenting a novel, field-deployable, upconversion system for sensitive, 2-D, mid-IR spectral imaging. Measured room temperature dark noise is 0.2 photons/spatial element/second, which is a billion times below the dark noise level of cryogenically cooled InSb cameras. Single photon imaging and up to 200 x 100 spatial elements resolution is obtained reaching record high continuous wave quantum efficiency of about 20 % for polarized incoherent light at 3 \mum. The proposed method is relevant for existing and new mid-IR applications like gas analysis and medical diagnostics

Gene Expression Patterns in Peripheral Blood Correlate with the Extent of Coronary Artery Disease

Systemic and local inflammation plays a prominent role in the pathogenesis of atherosclerotic coronary artery disease, but the relationship of whole blood gene expression changes with coronary disease remains unclear. We have investigated whether gene expression patterns in peripheral blood correlate with the severity of coronary disease and whether these patterns correlate with the extent of atherosclerosis in the vascular wall

A novel fluorescein-bisphosphonate based diagnostic tool for the detection of hydroxyapatite in both cell and tissue models

Abstract A rapid and efficient method for the detection of hydroxyapatite (HAP) has been developed which shows superiority to existing well-established methods. This fluorescein-bisphosphonate probe is highly selective for HAP over other calcium minerals and is capable of detecting lower levels of calcification in cellular models than either hydrochloric acid-based calcium leaching assays or the Alizarin S stain. The probe has been shown to be effective in both in vitro vascular calcification models and in vitro bone calcification models. Moreover we have demonstrated binding of this probe to vascular calcification in rat aorta and to areas of microcalcification, in human vascular tissue, beyond the resolution of computed tomography in human atherosclerotic plaques. Fluorescein-BP is therefore a highly sensitive and specific imaging probe for the detection of vascular calcification, with the potential to improve not only ex vivo assessments of HAP deposition but also the detection of vascular microcalcification in humans