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Background Despite anti-retroviral therapy, HIV-1 infection increases the risk of pneumonia and causes oxidative stress and defective alveolar macrophage (AM) immune function. We have previously determined that HIV-1 proteins inhibit antioxidant defenses and impair AM phagocytosis by suppressing nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Given its known effects on Nrf2, we hypothesize miR-144 mediates the HIV-1 induced suppression of Nrf2. Methods Primary AMs isolated from HIV-1 transgenic (HIV-1 Tg) rats and wild type littermates (WT) as well as human monocyte-derived macrophages (MDMs) infected ex vivo with HIV-1 were used. We modulated miR-144 expression using a miR-144 mimic or an inhibitor to assay its effects on Nrf2/ARE activity and AM functions in vitro and in vivo. Results MiR-144 expression was increased in AMs from HIV-1 Tg rats and in HIV-1-infected human MDMs compared to cells from WT rats and non-infected human MDMs, respectively. Increasing miR-144 with a miR-144 mimic inhibited the expression of Nrf2 and its downstream effectors in WT rat macrophages and consequently impaired their bacterial phagocytic capacity and H2O2 scavenging ability. These effects on Nrf2 expression and AM function were reversed by antagonizing miR-144 ex vivo or in the airways of HIV-1 Tg rats in vivo, but this protection was abrogated by silencing Nrf2 expression. Conclusions Our results suggest that inhibiting miR-144 or interfering with its deleterious effects on Nrf2 attenuates HIV-1-mediated AM immune dysfunction and improves lung health in individuals with HIV.

The rapid growth in the construction industry has dictated the utilisation of the eco-friendly materials and recycling of wastes to produce sustainable products. In this study, rubberized concrete interlocking bricks have been developed by utilising crumb rubber (10%) and fly ash (56%) as partial replacements of sand and OPC, respectively. It is aimed to develop mean and characteristic compressive strength correlations of rubberized concrete interlocking hollow and grouted wall systems, corresponding to rubberized concrete interlocking brick and prism strengths. A systematic investigation of 20 rubberized concrete interlocking brick units, 10 hollow and grouted rubberized concrete interlocking prisms and 10 identical hollow and grouted rubberized concrete interlocking wall panels were cast, constructed and tested under compressive load. Results were statistically analysed and the design-charts for the mean and characteristic compressive strength of masonry were used. The results obtained for the strength of rubberized concrete interlocking brick, prism and wall revealed a normal distribution with 5% significant interval. Four types of regression models were proposed for statistical analysis and the best fit model was identified based on r2 (correlation coefficient). The power model for the mean and characteristic strength curves presented the best fit to the sorted data. The cracking pattern and modes of failure of the tested specimens were discussed. The relationships for characteristic strengths of rubberized concrete interlocking masonry hollow and grouted wall were derived in terms of rubberized concrete interlocking unit and prism strength and found to be fkw = 1.533fb 0.290, fkw = 2.178fb 0.337 and fkw = 1.119fp0.659, fkw = 1.023fp0.731, respectively.

This paper analyses the bond behaviour of steel reinforcement bars in the matrix of nano-silica (NS)-modified self-consolidating engineered cementitious composites (SC-ECC). Presented first is the results of pull-out tests performed on three different diameters (12 mm, 16 mm, 20 mm) sizes of reinforcing steel bar embedded in the matrix. Subsequently, the results of the experiment are used in identifying the bond-slip relationship which explains the interactions between steel bars and matrix. A response surface methodology is applied to develop predictive models which are used to perform multi-objective optimization on bond-slip properties such as bond energy, bond slip and bond strength. Lastly, the experimental and predicted results obtained demonstrate that the developed models are suitable for the interpretation of the bond behaviour of steel bars embedded in the NS-modified cementitious matrix.

Due to its low carbon footprint and the capacity to be used for in situ applications, cast in-situ geopolymers are recognized as a feasible substitute of Portland cement. One of the limiting factors of using geopolymer in concrete sectors is dealing with viscous and dangerous alkaline alternatives, making it hard to adopt for mass concrete manufacturing. The advanced binder comprises of aluminosilicate components and granular sodium metasilicate to which water has been added like OPC. This document reports on the novel experimental method of producing cast in-situ alkali-activated binders using fly ash, ground granulated blast furnace slag (GGBS) and anhydrous sodium metasilicate. The defined method is described with a logical experimental study conducted to examine a feasible manufacturing method for casting in-situ geopolymer production. Replacement concentrations for slag were 0–100 percent by fly ash weight, while activator is used at 8%–16% of the complete binder content. The strengths, absorption rate and microstructural behaviour of cast in-situ alkali-activated pastes were regarded for up to 28 days. The resistance development of one-part/cast in-situ alkali-activated binders was discovered to be comparable to that of OPC. Microstructural assessment disclosed that the incorporation of GGBS in the paste resulted in structural changes of the in-situ geopolymer paste that could be attributed to the creation of C-A-S-H gel owing to the existence of extremely reactive alumina and silica in the source materials. Using the variance analysis, the impact of slag and sodium metasilicate activator on the behaviour of cast in-situ geopolymer pastes was acquired. The defined models were discovered to be important for all P-value reactions of

This paper discusses the influence of elevated temperature on the tensile properties (tensile strength, tensile strain, and energy absorption) and microstructure of nano-silica-modified self-consolidating engineered cementitious composites (NS-modified SC-ECC) mixtures. Response surface methodology (RSM) was utilized to develop a design matrix and predictive models and to perform multi-objective optimization for a matrix of mixtures prepared with polyvinyl alcohol (PVA) fiber at 0.5%, 1%, 1.5%, and 2% volume fractions and NS at 0%, 1%, 2%, 3%, and 4% of the weight of cementitious materials at temperatures of 23 °C, 100 °C, 200 °C, 300 °C, and 400 °C. To investigate the influence of elevated temperature on the certain characteristics of NS-modified SC-ECC mixtures, residual compressive strength, tensile properties, and microstructure properties were assessed at elevated temperatures of up to 400 °C for 1 h. Microstructure was examined using scanning electron microscopy before and after the mixtures had been exposed to elevated temperatures; accessible porosity and pore size distribution with cumulative pore volume were measured using mercury intrusion porosity (MIP) to validate the behaviors of the tensile properties and compressive strength of NS-modified SC-ECC mixtures. The results show that the tensile properties of the NS-modified SC-ECC mixtures improve due to pozzolanic reactivity of NS by utilizing the calcium hydroxide (CH) released from cement hydration to produce more calcium-silicate-hydrate (C-S-H) gel, which refines the fiber-matrix and aggregates-matrix interfacial transition zones (ITZ). The pozzolanic reactivity is further facilitated by temperature curing to produce more C-S-H gel, improving the fiber-matrix interactions at elevated temperatures of up to 200 °C. The PVA fiber improves the elevated temperature behavior of the mixtures and prevents explosive spalling behavior even after the incorporation of 2% NS with a PVA fiber volume of up to 2%. The responses considered in the RSM were tensile strength, tensile strain, and energy absorption. The established models showed high degrees of correlation between the responses and independent variables. Optimized tensile properties could be achieved at 2% PVA fiber volume, 1.3% NS, and a temperature of 125.7 °C. The measured absolute deviations (error) between the experimental data and the theoretical (predicted) models’ results for tensile strength, tensile strain, and energy absorption were 2.83%, 4.4%, and 1.68%, respectively.

The COVID-19 pandemic highlighted the significance of readily available and easily performed viral testing for surveillance during future infectious pandemics. The objectives of this study were: to assess the performance of the Xpert Xpress Flu and/or RSV test, a multiplex PCR assay for detecting influenza A and B virus and respiratory syncytial virus nucleic acids in respiratory tract specimens, relative to the Quidel Lyra Influenza A+B assay and the Prodesse ProFlu+ assay, and the system's ease of use by minimally trained operators. Overall, the Xpert Xpress Flu/RSV test demonstrated a high positive and negative percent agreement with the comparator assays, and was easy to use and interpret results, based on the operators' feedback. We concluded that the Xpert Xpress Flu/RSV test is sensitive, specific, and easy to use for the diagnosis of influenza and RSV by minimally trained operators and can be a valuable tool in future infectious clusters or pandemics.

Conventional bricks are made off from clay with high firing temperature or from cement concrete, but these consume and emit high energy and have environment shortcoming like carbon footprint and raw materials depletion. Researchers have utilized various types of waste materials in the production of bricks to protect the environment and contribute towards sustainable development. This study presents the latest research updates on utilizing waste materials in bricks manufacturing. The study categorized into two groups based on manufacturing method: fired and unfired methods. The review of literature exhibited an obvious potential of the waste materials as partial or total replacement of conventional raw materials where the produced bricks fulfilled the standards requirements. Additional research work is required, not just in the properties and economical parts but also on educating and aware the public about the advantages of utilizing waste materials in bricks manufacturing as well as on developing codes of practices and standards. © 2018 Elsevier Ltd

In this study, nano-silica (NS) has been incorporated into self-consolidating engineered cementitious composites (SC-ECC) for improving materials utilization and performance. Accordingly, the experimental results of the influence of nano-silica (NS) and polyvinyl alcohol (PVA) fibre on the high temperature resistance and microstructure of NS-modified SC-ECC is reported. Standard ECC mix (ECC M45) was adopted to develop mix matrix of composites with PVA fibre at 0.5%, 1%, 1.5%, and 2%, while NS at 1%, 2%, 3%, and 4% with the aim of investigating the behaviour of the materials at high temperatures. The NS-modified SC-ECC specimens were considered at various high temperatures up to 400 °C for residual compressive strength assessment using response surface methodology (RSM). While the microstructure of the mix containing 2% each of NS and PVA fibre at a high temperature up to 400 °C were investigated for microstructural properties through mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). The incorporation of NS and PVA fibre improved the performance of ECC due to the physiochemical effects and microcracks’ bridging ability of NS and PVA fibres, respectively, which was further confirmed by the microstructural studies. The developed prediction model using RSM shows a strong degree of correlation and predictability between the dependent (residual compressive strength) variable and the independent (NS, and PVA) variables after high temperatures exposure. The multi-objective optimization results revealed that the criteria settings at 2% each of NS and PVA fibre achieved a residual compressive strength of about 101 MPa while optimizing the high temperature resistance up to about 293 °C.

In this study, a method for determining the setting time and the porosity of fly ash-based geopolymer binders (FAGPBs) has been established. This method permits a real-time monitoring of the geopolymerisation and hardening progressions. A parallel plate capacitor cell technique was used to determine the dielectric constant e r ' and dielectric loss factor e r ' ' of fresh and hardened mixes. Equivalent model-circuits of the measurement system were developed, and the accuracy of the system was verified. The dielectric properties were monitored at different ages until 56 days over a frequency range of 0.1–60 MHz. The alkaline solution to fly ash ratio, sodium silicate to alkaline solution ratio, and sodium hydroxide solution molarity were varied to study their effects on the dielectric properties. It was found that dielectric properties can provide valuable information when measured in the frequency range of 10–25 MHz. In this range, the dielectric values responded well to the variations with age and with mix properties. The relationships between the dielectric properties and the different physical states and constituent materials of FAGPBs could be used for quality control applications. The e r ' and e r ' ' time plots were effectively utilized to determine the setting time and the rate of geopolymerisation of FAGPBs. Measurements showed a strong correlation between e r ' and porosity; the e r ' values decreased 2.3-fold over a porosity range of 3–15%. The proposed regression models can be further used in determining the porosity of FAGPBs at a high accuracy level.

New hybrid fibre reinforced cementitious composite developed using waste materials in the form of tirewires in combination with the PVA (Polyvinyl alcohol) fibers. The two kinds of fibres have been incorporated in the RSM (Response surface methodology) technique from the Design-expert software to evaluate the hybrid proportion of fibers. The Hybrid fibres in ECC (Engineered cementitious composite), with appropriate quantity of high and low modulus fibers is anticipated to enhance both the tensile strength (modulus of elasticity, bulk strength) and strain capacity (mainly for energy absorption). The fresh properties for self-compacting were satisfied according to EFNARC guidelines and observed that tirewire fibre diminished the workability and was preserved through the addition of PVA and superplasticizer. The hardened properties such as flexural strength, direct tensile strength, modulus of elasticity and shrinkage strain were optimized by developing the model equations through ANOVA (analysis of variance) validation with the more than 95% of significance. The appropriate proportions as 0.5% of tirewire and 1.5% of PVA fibers were obtained. The results revealed that the hybrid proportion of fibres adversely effected on workability and it produced a favourable influence on flexural strength, tensile strength and modulus of elasticity. The PVA fibres helped in increasing the strain hardening portion for the hybrid fibre reinforced engineered cementitious composite (HFRECC) and was able to maintain strain capacity up to 5%. The optimized results were validated experimentally with high desirability value of more than 0.97 and the variation between experimental and optimized results from RSM was found to be less than 5%.

Pericardial cysts are a rare disorder with an incidence of about 1 in 100,000, the majority of which are benign and incidentally identified. Pericardial cyst causing cardiac tamponade is an extremely rare phenomenon. The exact incidence of cardiac tamponade secondary to pericardial cyst is unknown. To the best of our knowledge limited case reports showing this association have been published. We have summarized cases showing this association in a tabular fashion. We present a case of a 36-year-old male who presented with symptoms of shortness of breath, chest pain, and fevers found to have ruptured pericardial cyst causing cardiac tamponade.

The major problems related to roller compacted concrete (RCC) pavement are high rigidity, lower tensile strength which causes a tendency of cracking due to thermal or plastic shrinkage, flexural and fatigue loads. Furthermore, RCC pavement does not support the use of dowel bars or reinforcement due to the way it is placed and compacted, these also aided in cracking and consequently increased maintenance cost. To address these issues, high volume fly ash (HVFA) RCC pavement was developed by partially replacing 50% cement by volume with fly ash. Crumb rubber was used as a partial replacement to fine aggregate in HVFA RCC pavement at 0%, 10%, 20%, and 30% replacement by volume. Nano silica was added at 0%, 1%, 2% and 3% by weight of cementitious materials to improve early strength development in HVFA RCC pavement and mitigate the loss of strength due to the incorporation of crumb rubber. The nondestructive technique using the rebound hammer test (RHT) and ultrasonic pulse velocity (UPV) were used to evaluate the effect of crumb rubber and nano silica on the performance of HVFA RCC pavement. The results showed that the use of HVFA as cement replacement decreases both the unit weight, compressive strength, rebound number (RN). Furthermore, the unit weight, compressive strength, RN, UPV and dynamic modulus of elasticity of HVFA RCC pavement all decreases with increase in crumb rubber content and increases with the addition of nano-silica. Combined UPV-RN (SonReb) models for predicting the 28 days strength of HVFA RCC pavement based on combining UPV and RN were developed using multivariable regression (double power, bilinear, and double exponential models). The exponential combined SonReb model is the most suitable for predicting the compressive strength of HVFA RCC pavement using UPV and RN as the independent variable with better predicting ability, higher correlation compared to the single variable models. Keywords: Crumb rubber, High volume fly ash, Nano silica, Roller compacted concrete pavement, Ultrasonic pulse velocity, Rebound number

The aim of this study is to evaluate the effects of inclusion nano-silica (also known as nano-SiO2) on the properties of pervious concrete containing fly ash (FA) as a partial replacement to cement. It has been found, for cementitious paste, that incorporating NS leads to reduce the cumulative pore volume by 13.4%. While the compressive strength of NS modified pervious concrete has been improved without adversely affecting its void ratio and permeability. The workability has been adversely affected by the inclusion of NS, which can be enhanced by incorporating the fly ash and superplasticizer. The porosity of cementitious paste has increased as the FA content is increased. These results are in good agreement with SEM results. For the pervious concrete voids ratio, permeability and infiltration rate were decreased against the increase of paste to the aggregate ratio Response surface methodology (RSM) has also been used to develop a model for navigating the design space of NS modified pervious concrete. Models revealed 95% significance of confidence level with difference less than 0.2 between Pred R-Squared value of 0.9515 and Adj R-Squared. The general expression has been developed for all the responses with the different coefficients using the RSM. Keywords: Fly ash, Final setting time, Infiltration rate, Pervious concrete, Nano-silica