Study of Kinetics and the Working Mechanism of Silica-Coated Amino-Functionalized CoFe2O4 Ferrite Nanoparticles to Treat Wastewater for Heavy Metals.

This study used a simple coprecipitation method to produce pristine, silica-coated, and amino-functionalized CoFe2O4 nanoadsorbents. Amino-functionalization was done to increase the active surface area and metal ion removal efficiency. Both pristine and functionalized adsorbents were employed to recover Pb(II), Zn(II), and Cu(II) ions from wastewater. The adsorption tests were performed by varying the initial concentration of metal ions and contact time at a fixed pH of 6.5. Atomic adsorption spectroscopy was utilized to detect the proportion of metals removed from water. Additionally, the pseudo-first-order, pseudo-second-order, Freundlich, and Langmuir models were employed to compute the kinetic and isothermic data from metal ion adsorption onto the adsorbents. The amino-functionalized adsorbent showed adsorption capacities of 277.008, 254.453, and 258.398 mg/g for Cu(II), Pb(II), and Zn(II) ions, respectively. According to the adsorption results, the Langmuir isotherm and the pseudo-second-order model best suit the data. The best fitting of the pseudo-second-order model with the data indicates that coordinative interactions between amino groups and metal ions are responsible for chemisorption. The metal ions bind with -NH2 groups on the adsorbent surface through chelate bonds. Chelate bonds are extremely strong and stable, indicating the effectiveness of the CoFe2O4@SiO2-NH2 adsorbent in adsorbing heavy-metal ions. The tested adsorbent exhibited good performance, batter stability, and good reusable values around 77, 81, and 76% for Cu(II), Pb(II), and Zn(II) ions, respectively, after five adsorption cycles.

Optimal Architecture of a Dual S-Scheme ZnIn2S4-ZnO-Al2O3 Heterosystem with High H2 Evolution Rate under Visible Light.

In this study, dual S-scheme ZnIn2S4-Al2O3-ZnO (ZIS-Al-Zn) heterojunctions were produced by a facile, low cost, and rapid combustion technique. These heterojunctions accelerated the photocatalytic hydrogen production due to the multi-channel-promoted separation of photocarriers. By optimizing the content of the components, the synthesized ZIS-Al-Zn composite with 20 wt% of ZnIn2S4 and 30 wt% of Al2O3 in the ZIS-Al-Zn composite demonstrated the highest hydrogen production rate of 54.2 mmol g-1 h-1, which was nearly 11 and 8.30 times better than ZnO-Al2O3 and ZnO-ZnIn2S4 composites, respectively. The results of DRS, PL, EIS, LSV, and CV techniques showed the highest shift in the light absorption, rapid interfacial transfer, and quenched recombination of photocarriers over the ternary ZIS-Al-Zn composite than single and binary catalysts. The obtained results revealed the formation of a dual S-scheme mechanism of transfer of photocarriers in ZIS-Al-Zn heterojunctions, contributing to better hydrogen production efficiency. The optimized ZIS-Al-Zn composite also exhibited good stability and reusability.

Semiconductor photocatalysts: A critical review highlighting the various strategies to boost the photocatalytic performances for diverse applications.

The photocatalytic technology illustrates an eco-friendly and sustainable route to overcome environmental and energy issues. The successful construction of a photocatalyst depends on four key elements: light absorption ability, the density of active sites, redox capacity, and photoinduced electron-hole recombination rate. Sincemost of intrinsic semiconductor photocatalysts cannot meet all these requirements, they are often modified to boost their photocatalytic properties. Many strategies have been adopted to design novel and efficient photocatalysts for diverse applications. Herein, we review the most efficient of these strategies and methods focused on effectively overcoming the efficiency limitations of photocatalysts to promote their large-scale application. Subsequently, a particular aim is put on the most current studies for photocatalytic applications, including CO2 reduction, N2 fixation, H2 evolution, and pollutants degradation. Finally, key challenges and future perspectives in designing and implementing semiconductor photocatalysts for large-scale applications are discussed. Therefore, it is foreseen that this review will work as a guide for future research and provides a variety of strategies to develop novel and high-performance photocatalysts for various applications.

Catalytic Hydrogen Evolution from H2S Cracking over CrxZnS Catalyst in a Cylindrical Single-Layered Dielectric Barrier Discharge Plasma Reactor.

The use of non-thermal plasma technology in producing green fuels is a much-appreciated environmentally friendly approach. In this study, an Al2O3-supported CrxZnS semiconductor catalyst was tested for hydrogen evolution from hydrogen sulfide (H2S) gas by using a single-layered dielectric barrier discharge (DBD) system. The Al2O3-supported CrxZnS catalyst (x = 0.20, 0.25, and 0.30) was produced by using a co-impregnation method and characterized for its structural and photocatalytic characteristics. The discharge column of the DBD system was filled with this catalyst and fed with hydrogen sulfide and argon gas. The DBD plasma was sustained with a fixed AC source of 10 kV where plasma produced species and UV radiations activated the catalyst to break H2S molecules under ambient conditions. The catalyst (hexagonal-cubic-sphalerite structure) showed an inverse relationship between the band gap and the dopant concentration. The hydrogen evolution decreased with an increase in dopant concentration in the nanocomposite. The Cr0.20ZnS catalyst showed excellent photocatalytic activity under the DBD exposure by delivering 100% conversion efficiency of H2S into hydrogen. The conversion decreased to 96% and 90% in case of Cr0.25ZnS and Cr0.30ZnS, respectively.

Construction of 0D/2D Schottky Heterojunctions of ZnO and Ti3C2 Nanosheets with the Enriched Transfer of Interfacial Charges for Photocatalytic Hydrogen Evolution.

The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti3C2, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti3C2 nanosheets. In constructing these heterojunctions, Ti3C2 nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti3C2 composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons' transport potential. The extended optical response and large reactive area of the ZnO/Ti3C2 composite promoted the formation of excitons and reactive sites on the photocatalyst's surface. The ZnO/Ti3C2 Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water-ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti3C2 composition with 30 wt.% of Ti3C2, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti3C2 as a low-cost co-catalyst.

Kinetics and Adsorption Isotherms of Amine-Functionalized Magnesium Ferrite Produced Using Sol-Gel Method for Treatment of Heavy Metals in Wastewater.

This study is focused on the kinetics and adsorption isotherms of amine-functionalized magnesium ferrite (MgFe2O4) for treating the heavy metals in wastewater. A sol-gel route was adopted to produce MgFe2O4 nanoparticles. The surfaces of the MgFe2O4 nanoparticles were functionalized using primary amine (ethanolamine). The surface morphology, phase formation, and functionality of the MgFe2O4 nano-adsorbents were studied using the SEM, UV-visible, FTIR, and TGA techniques. The characterized nanoparticles were tested on their ability to adsorb the Pb2+, Cu2+, and Zn2+ ions from the wastewater. The kinetic parameters and adsorption isotherms for the adsorption of the metal ions by the amine-functionalized MgFe2O4 were obtained using the pseudo-first-order, pseudo-second-order, Langmuir, and Freundlich models. The pseudo-second order and Langmuir models best described the adsorption kinetics and isotherms, implying strong chemisorption via the formation of coordinative bonds between the amine groups and metal ions. The Langmuir equation revealed the highest adsorption capacity of 0.7 mmol/g for the amine-functionalized MgFe2O4 nano-adsorbents. The adsorption capacity of the nanoadsorbent also changed with the calcination temperature. The MgFe2O4 sample, calcined at 500 °C, removed the most of the Pb2+ (73%), Cu2+ (59%), and Zn2+ (62%) ions from the water.

Evaluation of Ultrasonically ZnO Loading Effect on Photocatalytic Self-Cleaning, UV Protection and Antibacterial Activity of Plasma/Citric Acid-Activated Cotton Fabric.

Zinc oxide (ZnO) nanoparticles were loaded over non-thermal plasma (P1) and citric acid (P2)-functionalized cotton fabrics using a room temperature sonification process. The cotton samples were pretreated with dielectric barrier discharge (DBD) plasma and citric acid to introduce some reactive moieties on the fabric to enhance the adhesion power of ZnO nanoparticles with an average particle size of 41 nm. The nanoparticles were dispersed homogeneously on the surface of the P1 sample, which enhanced the antibacterial, UV protection and photocatalytic self-cleaning characteristics of ZnO-loaded fabric. The self-cleaning efficiency of P1 and P2 samples was measured to be about 77% and 63%, respectively. The inhibition zones of 5.5 mm and 5.4 mm were produced by sample P1 against E. coli and S. aureusbacteria, respectively, which were slightly higher than the inhibition zones produced by sample P2. The inhibition zone of the samples roughly decreased by 17% after performing 10 wash cycles. The unloaded cotton fabric had a UPF value of 70.02 units and blocking percentage of 70.92% and 76.54% for UVA and UVB radiations, respectively. The UVA-blocking capacity of samples P1 and P2 was 95.27% and 91.22, respectively. Similarly, the UVB blocking capacity was 94.11% and 92.65%, respectively. The pre-coating plasma treatment was found to be helpful in improving the UV-blocking ability of ZnO-loaded cotton fabric.

Pre-operative dosing of dexamethasone for the management of children with posterior fossa tumours: are we getting it right?

INTRODUCTION: Posterior fossa (PF) tumours are associated with vasogenic oedema causing symptoms of raised intracranial pressure. Preoperatively this is managed with dexamethasone. To minimise steroid related complications, the lowest effective dose should be administered. No neurosurgical guidelines exist for pre-operative dosing of dexamethasone in PF tumours. METHODS: A retrospective review was performed of surgically managed cases for patients under 16 years of age between 2013 and 2018 to ascertain the initial dose of dexamethasone with symptomatic PF tumours. RESULTS: Thirty-six patients were identified of which 30 notes were available. Sixteen were male. Median age was 6 years (range 10 months - 15 years). Twenty-two (73%) were referrals from DGH and 8 (27%) presented to our neurosurgical centre. All patients presented with symptomatic PF tumours including headache (97%), vomiting (93%), gait disturbance (43%), and nystagmus (17%). Four (13%) had papilloedema. Average initial stat dexamethasone dose was 9.15 mg; 0.31 mg/kg (range 1-16.7 mg; 0.05 - 1.77 mg/kg). Stratified according to weight, average dose (and range) was 8.8 mg; 0.94 mg/kg (1-16.6 mg; 0.13 - 1.77 mg/kg) in those weighing <10 kg; 9.7 mg; 0.66 mg/kg (4-16.7 mg; 0.21 - 1.35 mg/kg) in 10-20 kg; 12.3 mg;0.52 mg/kg (8-16.7 mg; 0.27 - 0.73mg/kg) in 20-30 kg and 7.8 mg; 0.17mg/kg (2-16.7 mg; 0.0 - 0.39 mg/kg) in >30 kg up to a maximum of 16.6 mg in any 24h period. These results suggest that dosage was higher in those children weighing less. PPI was used in 24 (80%) of cases. All doses were reduced after review by the neurosurgical team and a PPI added. CONCLUSION: Pre-operative dexamethasone dosing does not always reflect the severity of clinical symptoms for PF tumours. Guidelines are required to correlate clinical symptoms with a suggested suitable dose of dexamethasone to prevent overdose and complications associated with corticosteroid use. We recommend a weight-based regimen as provided by the Food and Drug Administration. The current advice is for 0.02-0.3mg/kg/day in 3-4 divided doses.

YY-11, a camel milk-derived peptide, inhibits TGF-ß-mediated atherogenic signaling in human vascular smooth muscle cells.

Atherosclerosis, the major underlying pathology of cardiovascular disease, commences with the binding and trapping of lipids on modified proteoglycans, with hyperelongated glycosaminoglycan chains. Transforming growth factor (TGF)-ß stimulates glycosaminoglycan elongation in vascular smooth muscle cells. We have recently shown that this TGF-ß signaling pathway involves reactive oxygen species (ROS). YY-11 is a dodecapeptide derived from camel milk and it has antioxidant activity. We have investigated the role of YY-11 in blocking ROS signaling and downstream atherogenic responses. YY-11 inhibited TGF-ß stimulated ROS production and inhibited the expression of genes for glycosaminoglycan chain elongation as a component of an in vitro model of atherosclerosis. This study provides a biochemical mechanism for the role of camel milk as a potential nutritional product to contribute to the worldwide amelioration of cardiovascular disease. PRACTICAL APPLICATIONS: The identification of readily accessible foods with antioxidant properties would provide a convenient and cost-effective approach community wide reducing oxidative stress induced pathologies such as atherosclerosis. We demonstrate that camel milk-derived peptide is an antioxidant that can inhibit growth factor-mediated proteoglycan modification in vitro. As proteoglycan modification is being recognized as one of the earliest atherogenic responses, these data support the notion of camel milk as a suitable nutritional product to contribute to the prevention of early stage of atherosclerosis development.

Camel milk as an alternative treatment regimen for diabetes therapy.

Camel milk is a valuable source of nutrition with a wide range of therapeutic effects. Its unique composition helps to regulate the blood glucose level. The current study is aimed to evaluate the antidiabetic and hepatoprotective effects, as well as lipid profile restoration of camel milk in the diabetic mouse model. This innovative study evaluates the therapeutic effects of camel milk in diabetic mice by simultaneous measurement of blood glucose, HbA1c, ALT, AST, TG, cholesterol, and histopathological studies. The results showed that camel milk has significantly reduced blood glucose, HbA1c (p < .001), aspartate transaminase (AST), alanine transaminase (ALT) (p < .01), triglyceride (TG), and cholesterol (p < .01), compared to that in the diabetic control group. Also, the therapeutic effects of camel milk were completely comparable with the antidiabetic drug glibenclamide. The results of this study suggest that camel milk could be used as a proper alternative treatment regimen for diabetes therapy.

Characteristics and Temperature Compensation of Non-Dispersive Infrared (NDIR) Alcohol Gas Sensors According to Incident Light Intensity.

This paper discusses the output characteristics of the sensor response of infrared ethanol gas detectors based on incident radiation intensity. Sensors placed at each focal point of two elliptical waveguides were fabricated to yield two module combinations and to verify the output characteristics. A thin Parylene-C film was deposited onto the reflector surfaces of one module. The thermal properties were compared between the sensor (2.0 Ø) and sensor with a hollow disk (1.6 Ø), the disk being mounted at the end of one detector. The fabricated sensor modules were placed inside a gas chamber. The temperature was increased from 253 K to 333 K, over the concentration range from 0 to 500 ppm. As the temperature increases by 10 K, the output of sensor (2.0 Ø) without and with Parylene-C coating typically increased by 70 mV and 52 mV, respectively. However, the sensor output with the hollow disk showed an average decrement of 0.8 mV/50 ppm and 1 mV/50 ppm for module without and with Parylene-C deposition, respectively. For concentrations higher than 50 ppm, the estimation error was around ±5%. Further, the sensitivity to temperature variation and the absorbance of infrared (IR) reflection was found higher for Parylene-C coated module.

Long term follow-up of infliximab efficacy in pulmonary and extra-pulmonary sarcoidosis refractory to conventional therapy.

INTRODUCTION: Infliximab, a humanized, chimeric, monoclonal antibody against tumor necrosis alpha (TNF-α), has been shown to reduce the pulmonary and extra-pulmonary manifestations of sarcoidosis, however, there is little information regarding sustained efficacy with long-term use of infliximab. We retrospectively investigate whether a reduction in disease response is maintained, over a prolonged course of therapy (up to 85 months) with infliximab, and report on adverse events associated with its use. METHODS: Subjects with multi-organ sarcoidosis were prescribed infliximab, between January 2000 to June 2010 due to failure of conventional therapy and were identified from the Drexel University College of Medicine sarcoidosis clinic. Retrospective patient reported symptom and objective clinical data analyses of pulmonary and extra-pulmonary findings were evaluated pre-infliximab and post or concurrent infliximab therapy. Any adverse events or reasons for discontinuation during infliximab therapy were reported. RESULTS: Twenty-six patients with biopsy proven sarcoidosis received anti-TNF therapy and met the criteria for study inclusion. Clinical evidence of sustained resolution or improvement was demonstrated in 58.5% of all organs assessed (p =<0.001). No clinical change in disease activity was seen in 35.8% of all organs evaluated. Despite infliximab treatment, 5.7% had progressive disease activity. Adverse events were seen in 57.7% of patients treated with infliximab over a 46.2 month average duration of therapy. Three (12%) patients had an adverse event that required permanent discontinuation. CONCLUSIONS: Infliximab is efficacious in the treatment of extra-pulmonary sarcoidosis and the efficacy is maintained with prolonged treatment. In patients with pulmonary sarcoid, sustained improvement in pulmonary imaging was seen after initiation of infliximab, however, post-treatment pulmonary function testing was not conclusive. Long-term infliximab therapy was well tolerated for our study group.