Bioactivity enhancement of calcined kaolin geopolymer with CaCl2 treatment

This paper reports that surface treatment with CaCl2 enhances the bioactivity of a calcined kaolin geopolymer. Calcined kaolin, NaOH solution, sodium silicate solution, and heat curing were used to form geopolymer pastes. A soaked-treatment method was applied to the geopolymer samples using CaCl2 solution as the ion exchange agent. The bioactivity of the material was determined by the simulated body fluid (SBF) in vitro testing method. Scanning electron microscope images showed a dense apatite formation on the treated geopolymer surface after SBF immersion for only 3 days. The CaCl2 treatment promoted compressive strength and enhanced bioactivity by accelerating apatite precipitation and slowing down the rise in pH.This work was financially supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, through the Advanced Functional Materials Cluster of Khon Kaen University; and Khon Kaen University and the Thailand Research Fund (TRF) under the TRF-Royal Golden Jubilee Ph. D. program (Grant no. PHD/0143/2554); Post-doctoral training program (Grant no. 58110), Graduate school, Khon Kaen University and TRF Senior Research Scholar Contract No. RTA5780004.info:eu-repo/semantics/publishedVersio

Apatite formation on calcined kaolin-white Portland cement geopolymer

In this study, calcined kaolin–white Portland cement geopolymerwas investigated for use as biomaterial. Sodiumhydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid (SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite was affected by the source material composition, alkali concentration and curing temperature. The calcined kaolin–white Portland cement geopolymer with relatively high compressive strength could be fabricated for use as biomaterial. The mix with 50% white Portland cement and 50% calcined kaolin had 28-day compressive strength of 59.0 MPa and the hydroxyapatite bio-layer on the 28-day soaked sample surface was clearly evident.This work was financially supported by the Thailand Research Fund (TRF) and Khon Kaen University under the TRF-Royal Golden Jubilee Ph.D. program (Grant No. PHD/0143/2554) and TRF-Senior Research Scholar (Grant No. RTA5780004)

The Gut Microbiota and Their Metabolites in Human Arterial Stiffness

Aim: Gut microbiota-derived metabolites, such as short-chain fatty acids (SCFAs) have vasodilator properties in animal and human ex vivo arteries. However, the role of the gut microbiota and SCFAs in arterial stiffness in humans is still unclear. Here we aimed to determine associations between the gut microbiome, SCFA and their G-protein coupled sensing receptors (GPCRs) in relation to human arterial stiffness. / Methods: Ambulatory arterial stiffness index (AASI) was determined from ambulatory blood pressure (BP) monitoring in 69 participants from regional and metropolitan regions in Australia (55.1% women; mean, 59.8± SD, 7.26 years of age). The gut microbiome was determined by 16S rRNA sequencing, SCFA levels by gas chromatography, and GPCR expression in circulating immune cells by real-time PCR. / Results: There was no association between metrics of bacterial α and β diversity and AASI or AASI quartiles in men and women. We identified two main bacteria taxa that were associated with AASI quartiles: Lactobacillus spp. was only present in the lowest quartile, while Clostridium spp. was present in all quartiles but the lowest. AASI was positively associated with higher levels of plasma, but not faecal, butyrate. Finally, we identified that the expression of GPR43 (FFAR2) and GPR41 (FFAR3) in circulating immune cells were negatively associated with AASI. / Conclusions: Our results suggest that arterial stiffness is associated with lower levels of the metabolite-sensing receptors GPR41/GPR43 in humans, blunting its response to BP-lowering metabolites such as butyrate. The role of Lactobacillus spp. and Clostridium spp., as well as butyrate-sensing receptors GPR41/GPR43, in human arterial stiffness needs to be determined

PASCal: A principal-axis strain calculator for thermal expansion and compressibility determination

We describe a web-based tool (PASCal; Principal Axis Strain Calculator) aimed at simplifying the determination of principal coefficients of thermal expansion and compressibilities from variable-temperature and variable-pressure lattice parameter data. In a series of three case studies, we use PASCal to re-analyse previously-published lattice parameter data and show that additional scientific insight is obtainable in each case. First, the two-dimensional metal-organic framework Cu-SIP-3 is found to exhibit the strongest area-negative thermal expansion (NTE) effect yet observed; second, the widely-used explosive HMX exhibits much stronger mechanical anisotropy than had previously been anticipated, including uniaxial NTE driven by thermal changes in molecular conformation; and, third, the high-pressure form of the mineral malayaite is shown to exhibit a strong negative linear compressibility (NLC) effect that arises from correlated tilting of SnO6 and SiO4 coordination polyhedra.Comment: 31 pages, 8 figures, formatted as preprint for J. Appl. Crys

Long-term Shedding of Influenza A Virus in Stool of Immunocompromised Child

In immunocompromised patients, influenza infection may progress to prolonged viral shedding from the respiratory tract despite antiviral therapy. We describe chronic influenza A virus infection in an immunocompromised child who had prolonged shedding of culturable influenza virus in stool

Bcl-2 protein family: Implications in vascular apoptosis and atherosclerosis

Apoptosis has been recognized as a central component in the pathogenesis of atherosclerosis, in addition to the other human pathologies such as cancer and diabetes. The pathophysiology of atherosclerosis is complex, involving both apoptosis and proliferation at different phases of its progression. Oxidative modification of lipids and inflammation differentially regulate the apoptotic and proliferative responses of vascular cells during progression of the atherosclerotic lesion. Bcl-2 proteins act as the major regulators of extrinsic and intrinsic apoptosis signalling pathways and more recently it has become evident that they mediate the apoptotic response of vascular cells in response to oxidation and inflammation either in a provocative or an inhibitory mode of action. Here we address Bcl-2 proteins as major therapeutic targets for the treatment of atherosclerosis and underscore the need for the novel preventive and therapeutic interventions against atherosclerosis, which should be designed in the light of molecular mechanisms regulating apoptosis of vascular cells in atherosclerotic lesions

Genomics of Ocular Chlamydia trachomatis After 5 Years of SAFE Interventions for Trachoma in Amhara, Ethiopia.

BACKGROUND: To eliminate trachoma as a public health problem, the World Health Organization recommends the SAFE (surgery, antibiotics, facial cleanliness, and environmental improvement) strategy. As part of the SAFE strategy in the Amhara Region, Ethiopia, the Trachoma Control Program distributed >124 million doses of antibiotics between 2007 and 2015. Despite this, trachoma remained hyperendemic in many districts and a considerable level of Chlamydia trachomatis (Ct) infection was evident. METHODS: We utilized residual material from Abbott m2000 Ct diagnostic tests to sequence 99 ocular Ct samples from Amhara and investigated the role of Ct genomic variation in continued transmission of Ct. RESULTS: Sequences were typical of ocular Ct at the whole-genome level and in tissue tropism-associated genes. There was no evidence of macrolide resistance in this population. Polymorphism around the ompA gene was associated with village-level trachomatous inflammation-follicular prevalence. Greater ompA diversity at the district level was associated with increased Ct infection prevalence. CONCLUSIONS: We found no evidence for Ct genomic variation contributing to continued transmission of Ct after treatment, adding to evidence that azithromycin does not drive acquisition of macrolide resistance in Ct. Increased Ct infection in areas with more ompA variants requires longitudinal investigation to understand what impact this may have on treatment success and host immunity

Microparticles from patients with metabolic syndrome induce vascular hypo-reactivity via Fas/Fas-ligand pathway in mice

Peer reviewedPublisher PD

Quantitative 3-Dimensional Imaging of Murine Neointimal and Atherosclerotic Lesions by Optical Projection Tomography

Traditional methods for the analysis of vascular lesion formation are labour intensive to perform - restricting study to ‘snapshots’ within each vessel. This study was undertaken to determine the suitability of optical projection tomographic (OPT) imaging for the 3-dimensional representation and quantification of intimal lesions in mouse arteries. = 0.85), confirming both the accuracy of this methodology and its non-destructive nature. It was also possible to record volumetric measurements of lesion and lumen and these were highly reproducible between scans (coefficient of variation = 5.36%, 11.39% and 4.79% for wire- and ligation-injury and atherosclerosis, respectively).These data demonstrate the eminent suitability of OPT for imaging of atherosclerotic and neointimal lesion formation, providing a much needed means for the routine 3-dimensional analysis of vascular morphology in studies of this type

Influence of hypoxia on the domiciliation of Mesenchymal Stem Cells after infusion into rats: possibilities of targeting pulmonary artery remodeling via cells therapies?

BACKGROUND: Bone marrow (BM) cells are promising tools for vascular therapies. Here, we focused on the possibility of targeting the hypoxia-induced pulmonary artery hypertension remodeling with systemic delivery of BM-derived mesenchymal stem cells (MSCs) into non-irradiated rats. METHODS: Six-week-old Wistar rats were exposed to 3-week chronic hypoxia leading to pulmonary artery wall remodeling. Domiciliation of adhesive BM-derived CD45(- )CD73(+ )CD90(+ )MSCs was first studied after a single intravenous infusion of Indium-111-labeled MSCs followed by whole body scintigraphies and autoradiographies of different harvested organs. In a second set of experiments, enhanced-GFP labeling allowed to observe distribution at later times using sequential infusions during the 3-week hypoxia exposure. RESULTS: A 30% pulmonary retention was observed by scintigraphies and no differences were observed in the global repartition between hypoxic and control groups. Intrapulmonary radioactivity repartition was homogenous in both groups, as shown by autoradiographies. BM-derived GFP-labeled MSCs were observed with a global repartition in liver, in spleen, in lung parenchyma and rarely in the adventitial layer of remodeled vessels. Furthermore this global repartition was not modified by hypoxia. Interestingly, these cells displayed in vivo bone marrow homing, proving a preservation of their viability and function. Bone marrow homing of GFP-labeled MSCs was increased in the hypoxic group. CONCLUSION: Adhesive BM-derived CD45(- )CD73(+ )CD90(+ )MSCs are not integrated in the pulmonary arteries remodeled media after repeated intravenous infusions in contrast to previously described in systemic vascular remodeling or with endothelial progenitor cells infusions