Synthesis of transparent bio-electrodes for biophysiological measurements based on modified graphene oxide.

The main objective of this work was to fabricate smart nanocomposite transparent conductive biophysiological electrodes based on modified graphene oxide (GO). The GO is abundant, flexible conductors that can be formulated as a transparent sheet and thereby alleviate the drawbacks of using indium tin oxide in transparent electrodes, like its scarcity, brittleness, and cost. GO was synthesized by a modified version of Hummers' method under highly acidic conditions with sulfuric acid and showed good distribution at a high temperature of 90 °C. Polyvinyl alcohol (PVA) was used as a polymer host in the composite. Glycerol (Gl) was used to increase the flexibility and conductivity through an esterification reaction. Characteristic techniques were used to detect the morphology and structure of GO fillers and their polymer composites, such as transmission electron microscopy, x-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The GO/Gl/PVA transparent nanocomposite was tested for the synthesis of electrocardiogram (ECG) and electrodermal (EDA) electrodes. The Biopac device was used to evaluate the behavior of the GO/Gl/PVA plastic transparent electrode in comparison to the GO/Gl/PVA black electrode and a commercial one. The results indicated improved efficiency of the GO/Gl/PVA ECG transparent electrode. The GO/Gl/PVA EDA electrode produced signals with higher conductivity and lower noise than the commercial electrode.

Evaluation of the nanofluid-assisted desalination through solar stills in the last decade.

Remote areas and poor communities are occasionally deprived of access to freshwater. It is, therefore, critical to providing a cheap and efficient desalination system that encourages the development of those communities and benefiting society at large. Solar stills are an affordable, direct method of water desalination, but its productivity is the critical challenge hindering its application. To ease this, research has focused on the role of nanofluids to improve heat transfer. Other works have focused on improving the design in consort with utilizing the nanofluids. This review reports and discusses the substantial role of nanofluids to enhance the productivity and energy utilization efficiency of the solar stills. Specifically, the mechanism of energy transfer between the nanoparticles and the base fluid. This includes both plasmonic and thermal effects. It is evident that nanofluid utilization in small fraction enhanced the thermal conductivity compared to base fluid alone. Alumina was found to be the most suitable nanoparticle used as nanofluid inside the solar stills due to its availability and lower cost. Still, other competitors such as carbon nanostructures need to be investigated as it provides higher enhancement of thermal conductivity. Also, several aspects of energy utilization enhancement have been discussed, including innovative application techniques. The challenges of such integrated systems are addressed as well.

Prosthetic mitral inflow mimicking severe aortic regurgitation (revisited). An echocardiographic challenge.

Assessing aortic regurgitation (AR) severity in patients with mitral valve prosthesis may pose an echocardiographic challenge. We present a case of mild AR in whom difficulty occurred in judging its severity due to eccentric mitral prosthetic inflow signals filling practically completely the proximal left ventricular outflow tract in diastole mimicking severe AR. Frame-by-frame analysis of two-dimensional transthoracic echocardiographic images using a small sector depth and width was helpful in clarifying the true severity of AR.

Prominent pulmonary venous flow mimicking mitral regurgitation.

The present case highlights a potential pitfall in assessing mitral regurgitation severity due to the presence of similar colored prominent pulmonary vein signals in the left atrium during color Doppler examination.

Comparing specific capacitance in rice husk-derived activated carbon through phosphoric acid and potassium hydroxide activation order variations.

This manuscript investigates the influence of the chemical activation step order and process parameters on the specific capacitance of activated carbon derived from rice husk. The chemical activation was performed either before or after the carbonization step, using phosphoric acid (H3PO4) and potassium hydroxide (KOH) as activating agents. For activation before carbonization, the carbonization process was conducted at various temperatures (600, 750, 850, and 1050 °C). On the other hand, for activation after carbonization, the effect of the volume of the chemical agent solution was studied, with 0, 6, 18, 21, 24, and 30 mL/g of phosphoric acid and 0, 18, 30, 45, 60, and 90 mL/g of 3.0 M KOH solution. The results revealed that in the case of chemical activation before carbonization, the optimum temperature for maximizing specific capacitance was determined to be 900 °C. Conversely, in the case of chemical activation after carbonization, the optimal volumes of the chemical agent solutions were found to be 30 mL/g for phosphoric acid (H3PO4) and 21 mL/g for potassium hydroxide (KOH). Moreover, it was observed that utilizing phosphoric acid treatment before the carbonization step leads to an 21% increase in specific capacitance, attributed to the retention of inorganic compounds, particularly silica (SiO2). Conversely, when rice husks were treated with KOH after the carbonization step, the specific capacitance was found to be doubled compared to treatment with KOH prior to the carbonization step due to embedding of SiO2 and KHCO3 inorganic constituents. This study provides valuable insights into the optimization of the chemical activation step order and process parameters for enhanced specific capacitance in rice husk-derived activated carbon. These findings contribute to the development of high-performance supercapacitors using rice husk as a sustainable and cost-effective precursor material.

Kinetic analysis of p-rGO/n-TiO2 nanocomposite generated by hydrothermal technique for simultaneous photocatalytic water splitting and degradation of methylene blue dye.

In this study, the nanocomposites of reduced graphene oxide/TiO2 (rGO/TiO2 with different percentages) have been synthesized using a modified Hummers' method followed by hydrothermal treatment. The morphology and bonding structure of the prepared samples have been characterized by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The photo-characteristic aspects of the prepared samples have been indicated by photoluminescence (PL) emission spectroscopy and ultraviolet-visible diffuse reflection spectroscopy (DRS). The photocatalytic performance of rGO/TiO2 demonstrated that it is an effective photocatalyst for methylene blue (MB) dye decomposition through illumination by a mercury lamp. Within 60 min of continuous irradiation, the nanocomposite-induced MB decomposition reached a rate of over 99%. Different MB concentrations and optimal percent loadings in catalysts have been investigated. Furthermore, the results showed that as the amount of catalyst increased, the decomposition of MB enhanced. Finally, the loading percentage of rGO with TiO2 has been studied, and an empirical equation relating the reaction rate constant until the mass of the photocatalyst and dye concentration has been proposed. The results showed that the prepared nanocomposites had good photocatalytic activity toward water splitting and photo-decomposition of MB.

Synergistic doping with Ag, CdO, and ZnO to overcome electron-hole recombination in TiO2 photocatalysis for effective water photo splitting reaction.

This manuscript is dedicated to a comprehensive exploration of the multifaceted challenge of fast electron-hole recombination in titanium dioxide photocatalysis, with a primary focus on its critical role in advancing the field of water photo splitting. To address this challenge, three prominent approaches-Schottky barriers, Z-scheme systems, and type II heterojunctions-were rigorously investigated for their potential to ameliorate TiO2's photocatalytic performance toward water photo splitting. Three distinct dopants-silver, cadmium oxide, and zinc oxide-were strategically employed. This research also delved into the dynamic interplay between these dopants, analyzing the synergetic effects that arise from binary and tertiary doping configurations. The results concluded that incorporation of Ag, CdO, and ZnO dopants effectively countered the fast electron-hole recombination problem in TiO2 NPs. Ag emerged as a critical contributor at higher temperatures, significantly enhancing photocatalytic performance. The photocatalytic system exhibited a departure from Arrhenius behavior, with an optimal temperature of 40°C. Binary doping systems, particularly those combining CdO and ZnO, demonstrated exceptional photocatalytic activity at lower temperatures. However, the ternary doping configuration involving Ag, CdO, and ZnO proved to be the most promising, surpassing many functional materials. In sum, this study offers valuable insights into how Schottky barriers, Z-scheme systems, and type II heterojunctions, in conjunction with specific dopants, can overcome the electron-hole recombination challenge in TiO2-based photocatalysis. The results underscore the potential of the proposed ternary doping system to revolutionize photocatalytic water splitting for efficient green hydrogen production, significantly advancing the field's understanding and potential for sustainable energy applications.

Effect of compression molding of CaCO3 powder on the kinetics of CO2 capture towards sustainable CO2 capture and sequestration cycle.

Reducing CO2 emissions from industrial sectors and motor vehicles is currently receiving much attention. There are different strategies for CO2 capture, one of which is using calcium oxide (CaO). In our proposed carbon dioxide cycle, limestone is first calcined to get CaO, which is then used to capture CO2 by converting it to CaCO3. Next, the released CO2 could be converted to different organic matter by different sequestration techniques. For this purpose, CaCO3 discs have been prepared by compression molding to investigate the effect of sintering temperature on the mechanical and chemical properties of CaO carbonation reaction. The aim of this work is to fill the knowledge gap for the effect of the contact profile between CO2 gas and CaO disc, particularly the effect of reducing the void fraction of CaO on the rate of carbonation reaction. It was found that the flexural strength of the CaO discs was influenced by several factors, such as the calcination temperature, duration of calcination, and pressing pressure. The carbonation step indicated that both CO2 and H2O are reacting with CaO simultaneously and progressively, with the progressive reaction of H2O and CO2 being a favorable route. The carbonation process happens as a surface reaction-controlled process followed by a slower internal diffusion-controlled process. Additionally, a kinetic study of the competing reactions indicated that two factors are controlling the process: diffusion of gases through the pores and then the reaction rate. Furthermore, our data showed that the CO2 uptake rate was 1352.34 mg/g CaO, indicating that 566.34 mg of CO2 was adsorbed inside the pores of the CaO disc. Based on these results, we propose a new mechanism of the sequence of the competing reactions. In summary, the CaO discs revealed a significant removal of CO2 from stack gases, which will be suitable for removing CO2 from exhaust gases generated by industrial processes and other sources of emissions such as vehicles and ships.

Electromagnetic field-enhanced novel tubular electrocoagulation cell for effective and low-cost color removal of beet sugar industry wastewater.

The treatment of real beet sugar mill effluent by a modified electrocoagulation process is proposed. An innovative design of an electromagnetic field-enhanced electrochemical cell consisting of a tubular screen roll anode and two cathodes (an inner and outer cathode) has been used. Different parameters have been investigated including current density, effluent concentration, NaCl concentration, rpm, number of screen layers per anode, and the effect of addition and direction of an electromagnetic field. The results showed that, under the optimum conditions, current density of 3.13 A/m2, two screens per anode, NaCl concentration of 12 g/l, and rotation speed of 120 rpm, the percentage of color removal was 85.5% and the electrical energy consumption was 3.595 kWh/m3. However, the presence of an electromagnetic field distinctly enhanced the energy consumption and the color removal percentage. Numerically, applying the magnetic field resulted in performing a color removal efficiency of 97.7% using a power consumption of 2.569 KWh/m3 which is considered a distinct achievement in industrial wastewater treatment process. The strong enhancement in color removal using a low power consumption significantly reduced the required treatment cost; the estimated treatment cost was 0.00017 $/h.m2. This design has proven to be a promising one for the continuous treatment of beet sugar industrial effluents and to be a competitor to the currently available techniques.

CdTiO3-NPs incorporated TiO2 nanostructure photocatalyst for scavenger-free water splitting under visible radiation.

Nanofibrous morphology and the doping technique can overcome the problem of electron/hole fast recombination and improve the activity of titanium oxide-based photocatalysts. In this study, nanoparticulate and nanofibrous forms of CdTiO3-incorporated TiO2 were synthesized with different cadmium contents; the morphology and composition were determined by SEM, TEM, EDX, and XRD techniques. The nanomorphology, cadmium content, and reaction temperature of Cd-doped TiO2 nanostructures were found to be strongly affect the hydrogen production rate. Nanofibrous morphology improves the rate of hydrogen evolution by around 10 folds over the rate for nanoparticles due to electron confinement in 0D nanostructures. The average rates of hydrogen production for samples of 0.5 wt.% Cd are 0.7 and 16.5 ml/gcat.min for nanoparticles and nanofibers, respectively. On the other hand, cadmium doping resulted in increasing the hydrogen production rate from 9.6 to 19.7 ml/gcat.min for pristine and Cd-doped (2 wt%) TiO2 nanofibers, respectively. May be the formation of type I heterostructures between the TiO2 matrix and CdTiO3 nanoparticles is the main reason for the observed enhancement of photocatalytic activity due to the strong suppressing of electron/holes recombination process. Consequently, the proposed photocatalyst could be exploited to produce hydrogen from scavenger-free solution. Varying reaction temperature suggests that hydrogen evolution over the proposed catalyst is incompatible with the Arrhenius equation. In particular, reaction temperature was found to have a negative influence on photocatalytic activity. This work shows the prospects for using CdTiO3 as a co-catalyst in photon-induced water splitting and indicates a substantial enhancement in the rate of hydrogen production upon using the proposed photocatalyst in nanofibrous morphology.

Improving the bioremediation technology of contaminated wastewater using biosurfactants produced by novel bacillus isolates.

Biosurfactants have many advantages outside chemical one, led for application it through different sectors. So, the present study aimed for improving the bioremediation technology of contaminated wastewater using biosurfactants produced by novel bacillus isolates. In this regard, Bacillus thuringiensis and Bacillus toyonensis strains were obtained as most producing isolates of highly active biosurfactants. The optimized conditions for high biosurfactants yield production were established. Also, the stability of the produced biosurfactants at various conditions, pH, temperature and salinity was studied. The biosurfactant has been reported up to 120 °C, pH 12 and 10% of NaCl. The identified biosurfactants, decanoic acid and oleamide were applied for wastewater remediation from oil residues and pathogens contamination. The biosurfactant was had high antibacterial activity compared with references antimicrobial drugs, as well as it is enhanced bioremediation technology for petroleum oil residues contaminating sites. Thus, we can say, these biosurfactants could achieve the objectives of sustainable development.

Fabrication of conductive human bio-nanoelectrode from graphene oxide modified with polyvinyl alcohol.

It is time for electrodes prepared from graphene oxide (GO) to replace the traditional electrodes. However, GO is an electrically insulating material. However, in this study, a conductive electrode was prepared from GO modification with glycerol (GL) under the esterification reaction at 90°C for 3 h with sulphuric acid as a catalyst under vacuum conditions. Polyvinyl alcohol (PVA) acts as a polymer host. It was mixed with GO and modification was carried out under heating conditions. The mixture of the GO/GL/PVA nanocomposite was rapidly cooled and poured into the electrode mould. Finally, it is placed in a desiccator at room temperature for two days. The characterisation (Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy) proved that the ester bond was formed and a complete distribution of GO/GL into the matrix of PVA was verified. The GO/GL/PVA nanocomposite was tested for electrocardiogram (ECG) electrodes. The biopic instrument was used to compare the behaviour of the GO/GL/PVA plastic electrode and the commercial one. The results indicated that the GO/GL/PVA plastic electrode efficiently detected ECG signals after two months with high conductivity and lower noise than the commercial electrode. The GO/GL/PVA plastic electrode has been reported for the first time in the literature.

Mersilene Mesh Brow Suspension: A New Modified Fox's Procedure - Five Years Clinical Experience.

PURPOSE: The aiming was to study the long-term clinical outcome and the merit of the author's modification of the fox's procedure. METHODS: Mersilene mesh brow suspension (MMBS) procedure was performed in 50 upper lids with severe blepharoptosis and poor levator function. RESULTS: The improvement in lid height was evaluated by preoperative and postoperative vertical palpebral aperture measurements and ranged from 2 to 6 mm (average 4 mm). The functional and cosmetically accepted results were maintained in 94% of the lids during mean follow-up of 39.4 months. CONCLUSION: In the present non-comparative study we believe that late Mersilene knot extrusion and forehead granuloma formation can be prevented by the modification adopted by the authors.