Correction: Acridinedione as selective flouride ion chemosensor: a detailed spectroscopic and quantum mechanical investigation

Correction for ‘Acridinedione as selective flouride ion chemosensor: a detailed spectroscopic and quantum mechanical investigation’ by Nafees Iqbal et al., RSC Adv., 2018, 8, 1993–2003.

The authors regret that the interpretation of the fluorescence spectra of compound 7i published in the original article was incorrect. In the original article, it was reported that upon excitation at 380 nm, the fluorescence spectrum of compound 7i showed two emission bands at 450 nm and 770 nm (Fig. 5b of the original article). The signal at 770 nm (previously reported as an emission band), is instead a second order diffraction (an artefact of diffraction grating/spectrofluorometer monochromator), as revealed from the literature.^1,2 The authors thank a reader for highlighting this mistake.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Response Surface Methodology and Artificial Neural Network Modelling of Membrane Rotating Biological Contactors for Wastewater Treatment

Membrane fouling is a major hindrance to widespread wastewater treatment applications. This study optimizes operating parameters in membrane rotating biological contactors (MRBC) for maximized membrane fouling through Response Surface Methodology (RSM) and an Artificial Neural Network (ANN). MRBC is an integrated system, embracing membrane filtration and conventional rotating biological contactor in one individual bioreactor. The filtration performance was optimized by exploiting the three parameters of disk rotational speed, membrane-to-disk gap, and organic loading rate. The results showed that both the RSM and ANN models were in good agreement with the experimental data and the modelled equation. The overall R² value was 0.9982 for the proposed network using ANN, higher than the RSM value (0.9762). The RSM model demonstrated the optimum operating parameter values of a 44 rpm disk rotational speed, a 1.07 membrane-to-disk gap, and a 10.2 g COD/m² d organic loading rate. The optimization of process parameters can eliminate unnecessary steps and automate steps in the process to save time, reduce errors and avoid duplicate work. This work demonstrates the effective use of statistical modeling to enhance MRBC system performance to obtain a sustainable and energy-efficient treatment process to prevent human health and the environment.     

Recycling of Waste Facial Masks as a Construction Material,a Step towards Sustainability

Amid the COVID-19 pandemic, a sudden surge in the production and utilization of disposable, single-use facial masks has been observed. Delinquency in proper disposal of used facial masks endangers the environment with a new form of non-biodegradable plastic waste that will take hundreds of years to break down. Therefore, there is an urgent need for the resourceful recycling of such waste in an environmentally friendly way. This study presents an efficient solution by using waste masks in fibered or crushed form to produce environmentally friendly and affordable green concrete. This investigation assessed the mechanical and durability properties of waste masks-incorporated concrete. A total of six mixes were prepared for standardized tests to determine compressive strength, split cylinder tensile strength and rapid chloride penetration test (RCPT), and freeze-thaw resistance. The percentage of mask fibers used were 0.5, 1, 1.5, and 2% of concrete by volume, while crushed masks were used at 0.5% only. The mask waste in both forms was found suitable to be used in concrete. One percent of waste mask fibers was found as an optimum value to increase compressive and tensile strength, reduce chloride permeability, and increase freeze-thaw resistance. Besides this, 0.5% crushed mask fiber also performed well, especially for producing less permeable and highly durable concrete. It is thus corroborated that waste masks that increase pollution worldwide can be utilized sustainably to help build green buildings. By reutilizing waste masks to produce improved concrete with better strengths and higher durability, circular economy and sustainability are achieved, along with efficient waste management.     

Visual outcomes and quality of life before and after photorefractive keratectomy

Purpose:To compare visual outcomes and vision-related quality of life (VRQoL) between subjects before and after photorefractive keratotomy (PRK) and controls. In addition, VRQoL was compared between subjects at different periods of PRK surgery.Methods:This was a cross-sectional study that included subjects with refractive errors aged 19–40 years and age-matched controls. Subjects were divided into three groups: pre-, post-PRK, and control. Subjects in the post-PRK group were divided into three subgroups (1-week, <6-month, and >6-month follow-up visits). Measurements including uncorrected distance visual acuity (UCVA), corrected distance visual acuity (CDVA), spherical equivalent (SE) of manifest refraction, and corneal topography were obtained for all participants. The Quality of Life Impact of Refractive Correction (QIRC) questionnaire was administered to compare VRQOL between groups and between post-refractive surgery subgroups.Results:A total of 145 participants were included in this study. The mean age ± standard deviation (SD) of all participants was 26.29 ± 5.1 years. There was a significant difference (P < 0.001) in total QIRC scores between groups. The total QIRC score was better in the post-PRK group than in the pre-PRK and control groups. The scores of items included in the convenience, well-being, and health concern domains were significantly higher in the post-PRK group than in the pre-PRK and control groups. Within the post-PRK group, significant differences (P < 0.001) were found in UCVA and SE between the post-PRK subgroups. Uncorrected VA and SE were better in the post-PRK groups who were followed up in the < 6 and > 6 months subgroups than in the 1-week follow-up subgroup (P < 0.0001).Conclusion:A significant improvement in visual outcomes and VRQoL occurred after PRK surgery. Subjects enjoyed their VRQoL after refractive surgery.     

Finite Element Analysis of the Ballistic Impact on Auxetic Sandwich Composite Human Body Armor

In this study, the ballistic impact behavior of auxetic sandwich composite human body armor was analyzed using finite element analysis. The auxetic core of the armor was composed of discrete re-entrant unit cells. The sandwich armor structure consisted of a front panel of aluminum alloy (Al 7075-T6), UHMWPE (sandwich core), and a back facet of silicon carbide (SiC) bonded together with epoxy resin. Numerical simulations were run on Explicit Dynamics/Autodyne 3-D code. Various projectile velocities with the same boundary conditions were used to predict the auxetic armor response. These results were compared with those of conventional monolithic body armor. The results showed improved indentation resistance with the auxetic armor. Deformation in auxetic armor was observed greater for each of the cases when compared to the monolithic armor, due to higher energy absorption. The elastic energy dissipation results in the lower indentation in an auxetic armor. The armor can be used safely up to 400 m/s; being used at higher velocities significantly reduced the threat level. Conversely, the conventional monolithic modal does not allow the projectile to pass through at a velocity below 300 m/s; however, the back face becomes severely damaged at 200 m/s. At a velocity of 400 m/s, the front facet of auxetic armor was destroyed; however, the back facet was completely safe, while the monolithic panel did not withstand this velocity and was completely damaged. The results are encouraging in terms of resistance offered by the newly adopted auxetic armor compared to conventional monolithic armor.     

A simple hydrothermal route for the preparation of novel Na–Y–W nano-oxides and their application in dye degradation

The fabricated NaY(WO₄)₂ was identified through diverse analysis methods. Therefore, to optimize NaY(WO₄)₂ morphology, saccharide carbohydrates were manipulated as a capping agent. In this study, glucose, fructose, lactose, cellulose, and starch were utilized as the capping agents. SEM images show that fructose was the optimal capping agent for achieving uniform and well-shaped nanoparticles. The photodegradation of organic dyes such as M.O and Rd.B by NaY(WO₄)₂ was evaluated under UV and Vis light. The bandgap energy of the as-prepared sample was measured by the Tauc plot, and was found to be nearly 3.85 eV. To study the photocatalytic characteristics, the influence of dye dosage and reusability on photodegradation behavior were investigated.

NaY(WO₄)₂ nanoparticles were fabricated via a simple hydrothermal method using saccharide carbohydrates as capping agents. The photocatalytic behavior of the as-prepared NaY(WO₄)₂ nanostructures was studied.     

Investigation on structure,thermodynamic and multifunctional properties of Ni–Zn–Co ferrite for Gd3+ substitution

This study presents a modification of structure-dependent elastic, thermodynamic, magnetic, transport and magneto-dielectric properties of a Ni–Zn–Co ferrite tailored by Gd³⁺ substitution at the B-site replacing Fe³⁺ ions. The synthesized composition of Ni_0.7Zn_0.2Co_0.1Fe_2−xGd_xO₄ (0 ≤ x ≤ 0.12) crystallized with a single-phase cubic spinel structure that belongs to the Fd$\bar{3}$m space group. The average particle size decreases due to Gd³⁺ substitution at Fe³⁺. Raman and IR spectroscopy studies illustrate phase purity, lattice dynamics with cation disorders and thermodynamic conditions inside the studied samples at room temperature (RT = 300 K). Ferromagnetic to paramagnetic phase transition was observed in all samples where Curie temperature (T_C) decreases from 731 to 711 K for Gd³⁺ substitution in Ni–Zn–Co ferrite. In addition, Gd³⁺ substitution reinforces to decrease the A-B exchange interaction. Temperature-dependent DC electrical resistivity (ρ_DC) and temperature coefficient of resistance (TCR) have been surveyed with the variation of the grain size. The frequency-dependent dielectric properties and electric modulus at RT for all samples were observed from 20 Hz to 100 MHz and the conduction relaxation processes were found to spread over an extensive range of frequencies with the increase in the amount of Gd³⁺ in the Ni–Zn–Co ferrite. The RLC behavior separates the zone of frequencies ranging from resistive to capacitive regions in all the studied samples. Finally, the matching impedance (Z/η₀) for all samples was evaluated over an extensive range of frequencies for the possible miniaturizing application.

This study presents a modification of structure-dependent elastic, thermodynamic, magnetic, transport and magneto-dielectric properties of a Ni–Zn–Co ferrite tailored by Gd³⁺ substitution at the B-site replacing Fe³⁺ ions.     

The great imposter: A case report of IgG4‐RD hypertrophic pachymeningitis with skull lytic lesion and pulmonary nodules

Immunoglobulin G4‐related disease (Ig4RD) is an inflammatory condition with unique clinical, serological, and pathological features. In this study, we report a challenging diagnostic clinical case of Ig4RD diagnosed based on histopathology. This unique imitating nature reinforces that it is crucial to consider the diagnosis of IgG4‐RD in those presenting with pachymeningitis.     

Left ventricular assist device implants in patients on extracorporeal membrane oxygenation: do we need cardiopulmonary bypass?

Open in a separate window OBJECTIVESImplanting a durable left ventricular assist device (LVAD) in a patient on extracorporeal life support (ECLS) is challenging. The goal of this study was to compare the results of patients from a European registry who had a durable LVAD implanted with or without transition from ECLS to cardiopulmonary bypass (CPB).METHODSA total of 531 patients on ECLS support who had an LVAD implant between January 2010 and August 2018 were analysed; after 1:1 propensity score matching, we identified and compared 175 patients in each group.RESULTSThe duration of preoperative ECLS was 7 [standard deviation (SD) 6] vs 7 (SD 6) days in patients with or without CPB (P = 0.984). The surgical time was longer in the CPB group [285 (SD 72) vs 209 [SD 75] min; P ≤ 0.001). The postoperative chest tube output was comparable [1513 (SD 1311) vs 1390 (SD 1121) ml; P = 0.3]. However, re-exploration for bleeding was necessary in 41% vs 29% of patients with or without CPB (P = 0.01) and a significantly higher number of packed red blood cells and fresh frozen plasma [8 (SD 8) vs 6 (SD 4) units; P = 0.001 and 6 (SD 7) vs 5 (SD 5) units; P = 0.03] were administered to patients operated on with CPB. A postoperative mechanical right ventricular support device was necessary in 50% vs 41% of patients (P = 0.08). The stroke rate was not significantly different (P 0.99). No difference in survival was observed.CONCLUSIONSOmitting CPB for an LVAD implant in patients on ECLS is safe and results in shorter operating time, less re-exploration for bleeding and fewer blood products. However, no survival benefit is observed.     

DFT-based study of the structural,optoelectronic, mechanical and magnetic properties of Ti3AC2 (A = P,As, Cd) for coating applications

The first-principles approach has been used while employing the Perdew–Burke–Ernzerhof exchange-correlation functional of generalized gradient approximation (PBE-GGA) along with the Hubbard parameter to study the structural, optoelectronic, mechanical and magnetic properties of titanium-based MAX materials Ti₃AC₂ (A = P, As, Cd) for the first time. As there is no band gap found between the valence and conduction bands in the considered materials, these compounds belong to the conductor family of materials. A mechanical analysis carried out at pressures of 0 GPa to 20 GPa and the calculated elastic constants C_ij reveal the stability of these materials. Elastic parameters, i.e., Young''s, shear and bulk moduli, anisotropy factor and Poisson''s ratio, have been investigated in the framework of the Voigt–Reuss–Hill approximation. The calculated values of relative stiffness are found to be greater than ½ for Ti₃PC₂ and Ti₃AsC₂, which indicates that these compounds are closer to typical ceramics, which possess low damage tolerance and fracture toughness. Optical parameters, i.e., dielectric complex function, refractive index, extinction coefficient, absorption coefficient, loss function, conductivity and reflectivity, have also been investigated. These dynamically stable antiferromagnetic materials might have potential applications in advanced electronic and magnetic devices. Their high strength and significant hardness make these materials potential candidates as hard coatings.

The first-principles approach has used the Perdew–Burke–Ernzerhof exchange-correlation functional of generalized gradient approximation along with the Hubbard parameter to study various properties of titanium-based MAX materials Ti₃AC₂ (A = P, As, Cd).