Damage Detection of FRP-Strengthened Concrete Structures Using Capacitance Measurements

In this study, a new concept for detecting air voids, water intrusion, and glue infiltration damages in fiber-reinforced polymers (FRPs)-strengthened concrete structures was developed. The concept, based on detecting the local dielectric permittivity variations, was employed to design coplanar capacitance sensors (CCSs) to detect such defects. An analytical model was used to introduce the sensor operation theory and analyze the influence of different sensor parameters on the output signals and to optimize sensor design. Two dimensional finite element (FE) simulations were performed to assess the validity of the analytical results and to evaluate other sensor design-related parameters. To experimentally verify the FE model, dielectric properties of various materials involved in FRP-strengthened concrete systems were measured. In addition, two concrete specimens strengthened with FRP laminates and containing preinduced defects were constructed and inspected in a laboratory setting. Good agreement was found between experimental capacitance measurements and those predicated by the FE simulations. The proposed CCS design, coupled with commercially available portable capacitance meters, would facilitate field implementation of the proposed technique for rapid inspection of FRP-strengthened concrete structures without the need for sophisticated data analyses usually required by other more expensive and time consuming methods.     

Prophylactic and therapeutic effects of taurine against aluminum-induced acute hepatotoxicity in mice

Aluminum is a well known neurotoxin and a possible candidate of hepatotoxins to humans. Using natural antioxidants against metal-induced hepatotoxicity is a modern approach. In the present study, Aluminum (AlCl₃) intoxication (a single injection of 25 mg Al³⁺/kg, i.p.) for 24 h in mice resulted in elevations in serum alanine aminotransferase activity and serum tumor necrosis factor and hepatic malondialdehyde levels. Aluminum reduced the activities of glutathione peroxidase, glutathione S-transferase, quinone oxidoreductase, and catalase in liver. In addition, Al caused hepatic hemorrhage, cellular degeneration as well as necrosis of hepatocytes. Ultrastructure examination showed swelling of mitochondria, derangement of rough endoplasmic reticulum cisternae and pleomorphic nuclei with abnormal chromatin distribution. Taurine, a sulfur-containing amino acid was administered to mice daily for 5 days before (at 100 mg/kg, i.p.) or 2 h after (a single dose of 1 g/kg, i.p.) aluminum administration. Treating mice with taurine at either dosing regimens, pre- or post-aluminum administration alleviated aluminum oxidative damaging effects. The rate of recovery was better when taurine was administered prior to Al. Taurine had anaphylactic and therapeutic activity against hepatotoxicity induced by aluminum in mice.     

Feasibility study of a hybrid photovoltaic/thermal collector system in the climate of Jordan

This study is dedicated to investigating the feasibility of photovoltaic/thermal (PV/T) collectors' technology for application in Jordan. Simple parallel-plate collector configurations were simulated using COMSOL: rectangular fins, triangular fins, and wavy walls. The wavy-wall configuration was found the most efficient alternative in terms of heat transfer with respect to the pumping power and performance factor that took into account the comparison with a plain-wall parallel-plate collector. However, the performance of the plain-wall parallel plate preceded that of the wavy wall by increasing the Reynolds number and the water channel height. The plain-wall parallel-plate configuration was further investigated on HOMER as a 5 MW solar plant that provides energy to a 5-MW facility. One MW of its load is direct thermal load. Different solar plant designs were compared. The PV/T plant was found to be very much energy saving but not feasible due to its high initial cost. However, the PV/T plant was better than the PV when the cooling was not complete compromising on some electric energy in favor of heat generation. Further work on reducing the cost of the PV/T collector is required especially with regard to contact methods between the PV and the absorber plate and to the weight of the collector.     

MHD conjugate heat transfer and entropy generation analysis of MWCNT/water nanofluid in a partially heated divided medium

The aim of this article is to conduct the lattice Boltzmann simulation of the magnetohydrodynamic (MHD) natural conjugate heat transfer in an apportioned cavity loaded with a multiwalled carbon nanotube/water nanofluid. The divided cavity is, to some extent, heated and cooled at the upright walls, whereas the horizontal walls are adiabatic. The nanofluid properties are evaluated on the basis of experimental correlations. The parameters ranges in the study are as follows: nanoparticles' volume fraction (%): 0 ≤ ? ≤ 0.5, temperature (°C): T = 27, Rayleigh number (Ra): 10³ ≤ Ra ≤ 10⁵, Hartmann number (Ha): 0 ≤ Ha ≤ 90, and the magnetic field inclination angle (γ): 0 ≤ γ ≤ π/2. The current outcomes are observed to be in great concurrence with the numerical results introduced in the literature. The impacts of the aforesaid parameters on local and average heat transfer, entropy generation, and Bejan number (Be) are explored and discussed. Indeed, the transfer of heat increases linearly with ? for a low Ra. As Ra increases, the average Nusselt number decreases for a high value of ?. The increase of nanoparticles' volume fraction leads to a reduction in the entropy generation and an increase in the Bejan number for a high Ra, but at low Ra, these functions remain constant. As the Ha increases, the transfer of heat and the entropy generation decreases, whereas there is an increase in Be. The transfer of heat, total entropy generation, and the Be depends strongly on the direction of the magnetic field. The increase of heater and cooler size has a great influence on the transfer of heat, entropy generation, and Be.     

Dielectric Response in the First Silicon Phthalocyanine Network Polymer

Unlike the well known silicon phthalocyanine polymers, which are only bridged polymers, the first silicon-phthalocyanine network polymer [PcSiCl₂] _x 6 was prepared from commercially available precursors. Based on previous modeling studies, elemental composition allowed for determination of both the shape and the content of Pc units in the prepared polymer. The two-dimensional network structure was found to offer an extension of the conjugation of the 18-π electron system of the phthalocyanine and facilitate the charge mobility across the material. This was found to enhance the conductivity and dielectric properties of the material, relative to the analogue materials, by supporting the hoping conduction mechanism. Differential scanning calorimetry was used to follow the non-oxidative thermal degradation of the prepared polymeric material. An interesting phenomenon, water effusion, was detected and proved to play a role in the conduction mechanism. Electrical and dielectric measurements were carried out at different frequencies. The polymer has extremely high values of the permittivity ε′ and dielectric loss ε″ at lower frequencies that decrease gradually with increasing frequency. The relaxation peak at lower frequencies showed without doubt that the moisture enhances the conductivity.     

Influence of "glow discharge plasma" as an external stimulus on the self-assembly, morphology and binding affinity of gold nanoparticle-streptavidin conjugates

In this study, we investigate the influence of glow discharge plasma (GDP) on the self-assembly, morphology and binding affinity of streptavidin coated gold nanoparticles (Au-NP-SV) and biotinylated antibody (bAb) adsorbed on a highly oriented pyrolytic graphite (HOPG) substrate. Atomic force microscope (AFM) was used to image the pre- and post-GDP treated samples. The analysis of the AFM images showed a considerable change in the aggregation and morphology of Au-NP-conjugates after treatment with GDP. To our knowledge, this is the first report on using GDP to enhance and speed-up the aggregation (sintering) of adsorbed NP biomolecular conjugates. These results show a promising route that could be generalized for other NPs and their conjugates. It can also be considered as an alternative and cheap aggregation method for controlling the binding affinity of biomolecular species on different surfaces with interesting applications.     

The California Tobacco Control Program's effect on adult smokers: (2) Daily cigarette consumption levels

Objective

To investigate the association of the California Comprehensive Tobacco Control Program with self‐reported population trends of cigarette consumption during 1992–2002.

Setting and Participants

Participants were non‐Hispanic white daily smokers (aged 20–64 years, n = 24 317) from the Tobacco Use Supplements to the Current Population Survey (1992–2002). We compared age‐specific trends in consumption among daily smokers in three groups of states with differing tobacco control initiatives: California (CA; high cigarette price/comprehensive programme), New York and New Jersey (high cigarette price/no comprehensive programme), and tobacco‐growing states (TGS; low cigarette price/no comprehensive programme).

Results

There was a general decline in cigarette consumption across all age groups in each category of states between 1992 and 2002, except the oldest age group in the TGS . The largest annual decline in the average number of cigarettes per day was observed among daily smokers in CA who were aged ⩾35 years (−0.41 cigarettes/day/year (95% CI −0.52 to −0.3)). This rate was significantly higher than the −0.22 cigarettes/day/year (95% CI −0.3 to −0.16; p<0.02) observed in same‐age daily smokers from New York and New Jersey, and significantly higher than the rate in same‐age daily smokers from the TGS (−0.15 cigarettes/day/year (95% CI −0.22 to −0.08; p<0.002)). There were no significant differences across state groups in the decline observed in daily smokers aged 20–34 years. In 2002, only 12% of daily smokers in CA smoked more than a pack per day, which was significantly lower than the 17% in New York and New Jersey, which again was significantly lower than the 25% in the TGS.

Conclusions

The California Tobacco Control Program was associated with significant declines in cigarette consumption among daily smokers aged ⩾35 years of age, which in turn should lead to declines in tobacco‐related health effects. The decline in consumption among young adult smokers was a national trend.Established statistical models from cohort studies have consistently demonstrated that smoking‐related diseases, especially lung cancer, vary exponentially with consumption level and smoking duration.^1,2,3,4 A significant reduction in the cigarette consumption level is therefore expected to reduce future risk of lung cancer in the population, which is demonstrated by several studies.^5,6,7 In recent years, there has been a call for harm‐reduction strategies to influence smoking levels in continuing smokers⁸; however, there are few studies of population trends and influences on cigarette consumption.^9,10Individual consumption levels differ considerably with age in the US. Typically, consumption levels increase in young adults, remaining relatively stable in middle‐aged adults, and decline in seniors.^9,11,12 Although public health strategies to reduce tobacco‐related disease have focused on promoting quitting and discouraging initiation,¹³ there is evidence that these strategies may also reduce cigarette consumption levels in the population. In this analysis, we assess the association of the California Tobacco Control Program with declines in cigarette consumption, in comparison with states having only high cigarette prices or with no tobacco control programme. Numerous studies have identified that increases in tobacco‐taxes lead to increases in cigarette prices and result in significant reductions in tobacco smoking behaviour.¹⁴ The decrease in cigarette consumption due to price increase has been shown to be a major contributor to the overall reduction in tobacco‐smoking behaviour,¹⁵ and many smokers reduce cigarette consumption before making an attempt to quit.¹⁶The California Comprehensive Tobacco Control Program that was introduced in 1989 was the first large state‐specific programme in the USA.¹⁷ This programme used funding from a dedicated increase in the tobacco excise tax to support a mass‐media counter‐advertising campaign, “grassroots” activism, particularly aimed at protecting non‐smokers from exposure to second‐hand smoke, school and community initiatives against smoking, and smoking cessation services. This programme introduced the first statewide ban on smoking in the workplace in 1994, which has been associated with reduced consumption levels among continuing smokers.^{18,19,20,21,22} From the start of the programme in 1989 to 2002, annual per capita cigarette sales in California (CA) declined by 60%, compared with 40% for the rest of the USA.²³In this report, we investigate the effect of the California Tobacco Control Program on daily consumption levels of daily smokers of differing age groups. We compare population trends for non‐Hispanic white daily smokers from CA with those in two comparison groups of states that have similar large combined populations and different tobacco control initiatives. One group is the top TGS with >90% of US tobacco production during the study period,²⁴ that had low excise taxes²⁵ and no comprehensive programme throughout the 1990s; this group includes Kentucky, Tennessee, North Carolina, South Carolina, Virginia and Georgia. The other group is New York and New Jersey, two neighbouring states that have a combined population size similar to CA and the TGS with tobacco excise taxes similar to CA during the 1990s²⁵ but no comprehensive tobacco control programme.For our analyses, we used state‐specific estimates of cigarette consumption among smokers from surveys of tobacco use in the US conducted by the Bureau of the Census between 1992 and 2002 in the Tobacco Use Supplements to the Current Population Survey (TUS‐CPS).     

Microwave heating effects on the chemical composition and the antioxidant capacity of tataouine virgin olive oils from Tunisia

Four Tunisian virgin olive oils (VOOs), derived from varieties (Chemlali Tataouine, Zarrazi Douirat, Fakhari Douirat, and Dhokar Douirat) grown in the harsh pedoclimatic conditions of the region of Tataouine, were evaluated for their responses to microwave heating. Aside from fatty acid composition, all other evaluated parameters were affected by microwave heating, and their variations depend on the genetic factor. Chemlali Tataouine VOO exhibited the slowest biophenol degradation rate and the least diminution in oxidative stability and consequently, its total fraction and both lipidic and methanolic fractions remained unchanged with an exceptional antioxidant potential. In the remaining studied VOOs, the biophenol contents, the oxidative stability, and the antioxidant potential underwent gradual decreases; nevertheless, their levels at the longer treatment time are close to some fresh VOOs. These results should be taken into consideration when Tataouine VOOs are recommended for microwave heating.     

The Relationship between COVID-19 and Hypothalamic–Pituitary–Adrenal Axis: A Large Spectrum from Glucocorticoid Insufficiency to Excess—The CAPISCO International Expert Panel

Coronavirus disease 2019 (COVID-19) is a highly heterogeneous disease regarding severity, vulnerability to infection due to comorbidities, and treatment approaches. The hypothalamic–pituitary–adrenal (HPA) axis has been identified as one of the most critical endocrine targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that might significantly impact outcomes after infection. Herein we review the rationale for glucocorticoid use in the setting of COVID-19 and emphasize the need to have a low index of suspicion for glucocorticoid-induced adrenal insufficiency, adjusting for the glucocorticoid formulation used, dose, treatment duration, and underlying health problems. We also address several additional mechanisms that may cause HPA axis dysfunction, including critical illness-related corticosteroid insufficiency, the direct cytopathic impacts of SARS-CoV-2 infection on the adrenals, pituitary, and hypothalamus, immune-mediated inflammations, small vessel vasculitis, microthrombotic events, the resistance of cortisol receptors, and impaired post-receptor signaling, as well as the dissociation of ACTH and cortisol regulation. We also discuss the increased risk of infection and more severe illness in COVID-19 patients with pre-existing disorders of the HPA axis, from insufficiency to excess. These insights into the complex regulation of the HPA axis reveal how well the body performs in its adaptive survival mechanism during a severe infection, such as SARS-CoV-2, and how many parameters might disbalance the outcomes of this adaptation.