Expression of concern: Acceleration of ammonium phosphate hydrolysis using TiO2 microspheres as a catalyst for hydrogen production.

Expression of concern for 'Acceleration of ammonium phosphate hydrolysis using TiO2 microspheres as a catalyst for hydrogen production' by Ayman H. Zaki et al., Nanoscale Adv., 2020, 2, 2080-2086, https://doi.org/10.1039/D0NA00204F.

Innovatively feasible wet incipient method for preparing Cu doped TiO2 nanocomposite: Electro-optical measurement supported by quantitative quantum and classical calculations.

The Cu-doped titanium oxide (Cu/TiO2) nanocomposite was systematically prepared using the innovatively feasible incipient wet impregnation method. Notably, the samples were derived from the raw materials through water dilution only. The successful formation of the host anatase TiO2 phase was confirmed by the characteristic peaks observed in the acquired X-ray powder diffraction (XRD) spectrum, which displayed intense peaks attributed to Cu2+ scattering sites, indicating the formation of crystallite Cu/TiO2 nanostructures. Dielectric measurements revealed that Cu/TiO2 possesses a higher dielectric permittivity compared to undoped TiO2. The conductivity for both structures exhibited a decreasing trend with increasing temperature. Interestingly, the measured optical properties indicated that Cu/TiO2 exhibited the minimum energy gap and maximum refractive index. This was further validated by qualitative time-dependent density functional calculation on a stable structural model, which was confirmed through semi-empirical molecular dynamic calculations. Thus, we have demonstrated the capability of our innovatively feasible synthesis method to produce the industrially important Cu-doped TiO2.

Efficacy and safety of ombitasvir/paritaprevir/ritonavir-based therapy in HCV patients with chronic kidney disease.

BACKGROUND AND STUDY AIMS: Hepatitis C virus (HCV) prevalence inchronic kidney disease (CKD) patients is significantly higher than in the general population. This study evaluated the efficacy and safety of combined ombitasvir/paritaprevir/ritonavir-based therapy in HCV patients with renal impairment. PATIENTS AND METHODS: Our study included 829 patients with normal kidney functions (group 1) and 829 patients with CKD (group 2),which were subdivided into patients not requiring dialysis (group 2a) and those on hemodialysis (group2b). Patients received regimens of ombitasvir/paritaprevir/ritonavir with or without ribavirin or sofosbuvir/ombitasvir/paritaprevir/ritonavir with or without ribavirin for 12 weeks. Clinical and laboratory assessment was done before treatment, and patients were followed up for12 weeks after treatment. RESULTS: The sustained virological response (SVR) at week 12 was significantly higher in group 1 than in the other three groups/subgroups, being 94.2% vs 90.2%, 90%, and 90.7%, respectively. The regimen with the highest SVR was ombitasvir/paritaprevir/ritonavir with ribavirin. The most common adverse event was anemia, which was more common in group 2. CONCLUSION: Ombitasvir/paritaprevir/ritonavir-based therapy in chronic HCV patients with CKD is highly effective, with minimal side effects despite ribavirin-induced anemia.

Electronic Structures and Electrical Properties of Cr2+-, Cu2+-, Ni2+-, and Zn2+-Doped Sodium Titanate Nanotubes.

Sodium titanate nanotubes (Na-TNTs) and their metal-doped derivatives were prepared using simple hydrothermal and metal ion-exchange methods, respectively. The as-prepared doped materials were characterized by X-ray powder diffraction, thermal gravimetric analysis, high-resolution transmission electron microscopy, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The dielectric constant, the loss tangent, and the AC electrical conductivity of NaM-TNTs (where M = Cr, Cu, Ni, or Zn) were measured at selected frequencies (400 kHz and 2 MHz) as a function of temperature. The activation energy was calculated and reported at 400 kHz. All samples showed mixed ionic electronic conductivity. Some of the materials were used as examples for theoretically exploring structures and optoelectronic properties (density of states, reflectivity, absorption curve, refractive index, dielectric function, optical conductivity, and loss function) using density functional theory calculations. The band gaps of the materials were found to vary from 2.4 to 3.17 eV, which makes them suitable for many optoelectronic applications.

In-situ construction of Zr-based metal-organic framework core-shell heterostructure for photocatalytic degradation of organic pollutants.

Photocatalysis is an eco-friendly promising approach to the degradation of textile dyes. The majority of reported studies involved remediation of dyes with an initial concentration ≤50 mg/L, which was away from the existing values in textile wastewater. Herein, a simple solvothermal route was utilized to synthesize CoFe2O4@UiO-66 core-shell heterojunction photocatalyst for the first time. The photocatalytic performance of the as-synthesized catalysts was assessed through the photodegradation of methylene blue (MB) and methyl orange (MO) dyes at an initial concentration (100 mg/L). Under simulated solar irradiation, improved photocatalytic performance was accomplished by as-obtained CoFe2O4@UiO-66 heterojunction compared to bare UiO-66 and CoFe2O4. The overall removal efficiency of dyes (100 mg/L) over CoFe2O4@UiO-66 (50 mg/L) reached >60% within 180 min. The optical and photoelectrochemical measurements showed an enhanced visible light absorption capacity as well as effective interfacial charge separation and transfer over CoFe2O4@UiO-66, emphasizing the successful construction of heterojunction. The degradation mechanism was further explored, which revealed the contribution of holes (h+), superoxide (•O2 -), and hydroxyl (•OH) radicals in the degradation process, however, h+ were the predominant reactive species. This work might open up new insights for designing MOF-based core-shell heterostructured photocatalysts for the remediation of industrial organic pollutants.

Effect of Different TiO2 Morphologies on the Activity of Immobilized Lipase for Biodiesel Production.

Lipase catalytic activity is greatly influenced by immobilization on nanoparticles. In this study, lipase from Aspergillus niger was immobilized on TiO2 nanoparticles with different morphologies: microspheres, nanotubes, and nanosheets. All TiO2 samples were prepared by a hydrothermal method. Lipase/TiO2 nanocomposites were prepared by a physical adsorption method through hydrophobic interactions. The prepared composites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The catalytic activity of free and immobilized lipases was tested using sunflower oil in the presence of methanol to produce biodiesel at 40 °C for 90 min. The lipase immobilized on TiO2 microspheres showed the highest activity compared to the lipase immobilized on TiO2 nanotubes and nanosheets. To optimize the lipase-to-microsphere ratio, lipase was immobilized on TiO2 microspheres in different microspheres/lipase, w/w, (S/L) ratios of 1:1, 1:0.75, 1:0.5, and 1:0.25. It was noticed that the hydrolytic activity follows the order 1:0.25 > 1:0.5 > 1:75 > 1:1. The immobilization yield activities were found to be 113, 123, 125, and 130% for the microspheres/lipase (S/L) ratios of 1:1, 1:0.75, 1:0.5, and 1:0.25, respectively.

Real-world safety and effectiveness of retreatment of Egyptian chronic hepatitis C patients not responding to NS5A inhibitor-based therapies.

The aim of this study was to assess the efficacy and safety of two protocols for retreatment of a cohort of Egyptian patients with chronic hepatitis C (CHC) who relapsed after NS5A inhibitor-based therapy. We conducted a prospective cohort study to assess the safety and efficacy of 12 weeks' retreatment with either combination of sofosbuvir/daclatasvir/simeprevir plus ribavirin (SOF/DCV/SMV/RBV, n = 45) or sofosbuvir/ombitasvir/paritaprevir/ritonavir plus ribavirin (SOF/OBV/PTV/r/RBV, n = 163) in patients who had previously failed NS5A inhibitors-based regimens. The primary end point was SVR 12 weeks after the end of treatment (SVR12). Safety follow-up data were recorded for 60 weeks after the end of treatment. Two hundred-eight patients were included in the study. Of them, 53.4% of patients were females and 40.4% had liver cirrhosis. The most common prior drug combinations were sofosbuvir/daclatasvir (n = 94) and sofosbuvir/daclatasvir plus ribavirin (n = 109). The overall SVR12 rates were 98.1%. In SOF/DCV/SMV/RBV group, 95.6% achieved SVR12, while in SOF/OBV/PTV/r/RBV group, the SVR12 rates were 98.8%. SVR12 was higher in cirrhotic patients (84/84) than noncirrhotic (120/124), P value = .0149. Regarding the safety outcomes, anaemia and fatigue were significantly higher in SOF/OBV/PTV/r/RBV group. Hepatocellular carcinoma (HCC) was reported in eight (3.8%) patients (four in each group). Of them, death was confirmed in four patients. Retreatment of Egyptian CHC relapsed patients with either sofosbuvir/daclatasvir/simeprevir plus ribavirin or sofosbuvir/ombitasvir/paritaprevir/ritonavir plus ribavirin is highly effective and well-tolerated for both noncirrhotic and compensated cirrhotic patients. Incidental de novo HCC and hepatic decompensation are comparable in the two groups.

Acceleration of ammonium phosphate hydrolysis using TiO2 microspheres as a catalyst for hydrogen production.

Titania microspheres are considered an adequate material with low cost and easily attainable pathways, and can be utilized in photocatalytic H2 production to solve the energy crisis. Spherical porous titanium dioxide materials, with nanostructure composition, were chemically synthesized from titanate nanotubes via a simple hydrothermal technique, then added as a catalyst to accelerate the route of ammonium phosphate hydrolysis for hydrogen production. The mechanism of sphere formation from titanate nanotubes is elucidated in detail through the current study. The prepared materials were applied as a photocatalyst to facilitate the separation and transfer of photoinduced electrons, while preventing the recombination of electron-hole pairs. Experimental results show that the obtained microspheres possess significantly enhanced photocatalytic hydrogen (H2) production performance. The amount of photocatalytic hydrogen product using the microspheres is found to be ∼2.5 fold greater than that of titanate nanotubes. Analytical techniques such as field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM), simulated visible solar light and X-ray diffraction (XRD) were used for the evaluation and characterization of the developed products, as well as the elucidation of the route of hydrolysis in the hydrogen production process.

Effects of K+, Mg2+, Ca2+, Zn2+, La3+, Cr3+, Ce3+, Ce4+, and Mo5+ Doping on the Adsorption Performance and Optical Properties of Sodium Titanate Nanotubes.

Metal-doped titanate nanotubes (TNTs) were synthesized using a simple ion-exchange method. Cations with different valencies (Mg2+, Ca2+, Zn2+, K+, Cr3+, Ce3+, Ce4+, Mo5+, and La3+) were used to assess their effects on the adsorption performance and optical properties of the prepared nanotubes. All samples were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDXS), and elemental mapping, and the optical properties were analyzed using photoluminescence (PL) spectroscopy. The adsorption performance of the prepared doped titanate nanotubes was tested against methylene blue (MB) as a model cation dye. The results revealed that all samples except Ce(IV)-TNT showed high removal efficiencies but at different equilibrium times. Mg-TNT, Zn-TNT, and K-TNT showed higher MB removal percentages (97%) after 45 min, while Ca-TNT, Cr-TNT, Ce(III)-TNT, Mo-TNT, La-TNT, and Na-TNT showed removal efficiencies of 95, 84, 95, 96, 94, and 96% after 65, 1200, 120, 300, 180, and 105 min, respectively. The titanate nanotubes were recycled by photocatalytic degradation of the adsorbed dye molecules. The band gaps, valence band, and conduction band were calculated and compared for the potential photocatalytic water splitting application.

Sodium titanate nanotubes for efficient transesterification of oils into biodiesel.

In this work, sodium titanate nanotubes were prepared by a hydrothermal method for 23 h at 160 °C and characterized by high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) methods, and Fourier transform infrared (FT-IR) spectroscopy. The obtained nanotubes were used as catalysts in the transesterification of pure and cooked oils under different experimental conditions (molar ratio, temperature, catalyst weight, and time). The catalyst showed high efficiency depending on the chosen conditions. The biodiesel yield was found to be 95.9% at 80 °C for 2 h. The catalyst also showed high activity for cooked oil conversion, with yields of 96.0, 96.0, and 93.58% for the first, second, and third uses of oil, respectively. The methanol was recycled and used in another transesterification experiment, and the biodiesel yield reached 91%. Density functional theory, Monte Carlo simulation, and molecular dynamics simulation were employed to clearly understand the transesterification mechanism. The transesterification reaction is represented by a pseudo-first-order kinetics model. Graphical Abstract .

Prevalence of occult hepatitis C virus infection in patients who achieved sustained virologic response to direct-acting antiviral agents.

The reappearance of HCV infection months or years after sustained virologic response (SVR) may be due to the persistence of HCV in tissue cells in spite of being undetected in serum. This situation is known as occult hepatitis C infection (OCI). We aimed to assess the prevalence of OCI in Egyptian patients with chronic hepatitis C (CHC) who achieved SVR after treatment with direct-acting antiviral agents (DAA). We carried out a cross-sectional study at the Advanced Center for Liver Diseases of Zagazig University Hospitals and Al-Ahrar Viral Hepatitis Treatment Center, Sharkia Governorate, Egypt. One hundred and fifty adult patients with CHC, who achieved SVR 12-24 weeks after end of treatment with sofosbuvir/daclatasvir ± ribavirin (139 patients, 92.67%), sofosbuvir/ledipasvir ± ribavirin (eight patients, 5.33%), sofosbuvir/simeprevir (two patients, 1.33%), and ombitasvir/ paritaprevir/ritonavir + ribavirin (one patient, 0.67%), according to the Egyptian National Committee for Control of Viral Hepatitis, were included in the study. We tested these patients for HCV RNA in peripheral blood mononuclear cells (PBMCs) immediately after confirmation of SVR12-24 weeks. Statistical analysis was performed by means of the Shapiro-Wilk test, Mann-Whitney U test, Chi-square test, and Fisher's exact test. Seventeen patients (11.33%) were positive for PBMNCs HCV RNA. The prevalence of OCI was highest in patients treated with simeprevir/sofosbuvir (2/2 patients). There is a substantially high prevalence of OCI after treatment with DAAs. We recommend dual testing for HCV RNA in both serum and PBMCs at the end of treatment of HCV infection with DAAs and during validation of the SVR following the initial response.