The application of a new recyclable photocatalyst γ-Fe2O3@SiO2@ZIF8-Ag in the photocatalytic degradation of amoxicillin in aqueous solutions.

This pilot study synthesized the γ-Fe2O3@SiO2@ZIF8-Ag nanocomposites via the hydrothermal method to study its potential use in amoxicillin degradation as a novel photocatalyst in aqueous solutions under visible light radiation. Various diagnostic methods were used to determine the morphology and functional structure of the photocatalyst, and the results confirmed its proper formation. Complete degradation of AMX was obtained at a pH of 5, catalyst dosage of 0.4 g/L, AMX concentration of 10 mg/L, and reaction time of 60 min. The efficiency of the degradation was diminished when anions were present in the reaction medium, and the order of their effect was SO42- < Cl- < NO3- < HCO3-. Biodegradability (BOD5/COD ratio) increased from 0.20 to 0.68 after 120 min of photocatalytic treatment, with a COD removal of 87.54% and a TOC removal of 74.88%. Through the experimental trapping of electrons, we found the production of reactive species, such as hydroxyl radical (•OH), superoxide (O2•-), and holes (h+), in the photocatalysis reactor and that •OH was the predominant species in AMX photodegradation. Comparative experiments emphasized that the oxidation process occurs with the adsorption of pollutants on the surface of the catalyst, and the photocatalyst has the potential to be activated by various light sources, including visible light, UV light, and sunlight, with an AMX decomposition above 88%. The synthesized particles can be recovered after five consecutive cycles with minimal reduction in the degradation rate (< 4%). γ-Fe2O3@SiO2@ZIF8-Ag can be considered a promising photocatalyst for use in AMX degradation due to its recyclability, easier activation by different light sources, and excellent mineralization.

Efficient photocatalytic degradation of metronidazole in wastewater under simulated sunlight using surfactant- and CuS-activated zeolite nanoparticles.

Hexadecyltrimethylammonium-bromide-activated zeolite nanoparticles coated with copper sulfide (ZEO/HDTMA-Br/CuS) was evaluated as a photocatalyst under sunlight for the degradation of metronidazole (MET). The surface and structural characteristics of ZEO/HDTMA-Br/CuS and other materials used in this study were analyzed using field emission-scanning electron microscopy, Fourier transform infrared and ultraviolet-visible diffuse reflectance spectroscopies, X-ray diffraction, Brunauer-Emmett-Teller surface area and Barrett-Joyner-Halenda pore size and volume analyses, and pH of zero charge test. ZEO/HDTMA-Br/CuS exhibited excellent surface and structural catalytic properties. For a comprehensive study of the degradation process, several parameters, such as the pH (3-11), MET concentration (10-30 mg/L), ZEO/HDTMA-Br/CuS dose (0.005-0.1 g/L), reaction time (5-200 min), and H2O2 concentration (50-200 mg/L), were optimized. ZEO/HDTMA-Br/CuS achieved 100% degradation efficiency when 10 mg/L MET was used under the optimum conditions: pH = 7, ZEO/HDTMA-Br/CuS dose = 0.01 g/L, and reaction time = 180 min. The degradation efficiency increased when the concentration of H2O2 was increased from 50 to 150 mg/L and decreased with further increase to 200 mg/L, indicating that the efficiency of MET degradation highly depends on the concentration of H2O2 in an aqueous solution. The degradation kinetics analysis revealed that the degradation is of the pseudo first-order. Thus, ZEO/HDTMA-Br/CuS proved to be an exceptional catalyst for the photodegradation of MET in aqueous media.

Development of sonophotocatalytic process for degradation of acid orange 7 dye by using titanium dioxide nanoparticles/graphene oxide nanocomposite as a catalyst.

In the present study, the sonophotocatalytic degradation of acid orange 7 (AO7) dye was evaluated. The catalyst used was the titanium dioxide nanoparticles/graphene oxide (TiO2/GO) nanocomposite, which was synthesized using the Hummers and Hoffman's method and the liquid phase deposition method. TiO2/GO nanocomposite was characterized through the analyses of transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. In addition, properties of the surface area and pore size were determined by N2 adsorption-desorption and the Barrett-Joyner-Halenda methods. After modification, the nanocomposite properties showed successful stabilization of TiO2 on the graphene substrate and reduction of the recombinant carrier loads. By utilizing the proposed treatment, complete degradation of AO7 could be achieved under optimal operating parameters (pH = 5, initial concentration of AO7 dye = 50 mg/L, TiO2/GO nanocomposite dose = 0.5 g/L, UV light intensity = 36 W, ultrasonic wave intensity = 35 kHz, and reaction time = 30 min). Scavenging experiments confirmed that OH and h+ radicals were the predominant species in the sonophotocatalytic degradation reactions of the AO7 dye. The stability study confirmed the excellent shelf life of the TiO2/GO nanocomposite, with only a slight reduction in the degradation efficiency of the AO7 dye (<8.27%) detected, after six consecutive cycles of the sonophotocatalytic process. Studies related to the degradability of the AO7 dye and the biodegradability of the effluent from the process showed that the applied sonophotocatalytic system was able to remove the TOC concentration by 83% after a reaction time of 30 min. Moreover, the increase in the BOD5/COD ratio was also a confirmation for the increase in biodegradability of the treated AO7 dye effluent. Finally, the toxicity test showed that the growth inhibition rate of Escherichia coli (E. coli), as a viability index, decreased to about 7.34% after a reaction time of 180 min. This result indicated the formation of compounds with low toxicity and molecular weight over the reaction time of the sonophotocatalytic process of AO7 dye.

An electrochemical sensor for the determination of environmentally hazardous fungicide pyrimethanil in water and fruit samples.

We developed a facile electroanalytical system for the rapid and sensitive detection of pyrimethanil through the modification of carbon paste electrode surface using the as-fabricated europium doped feather-type CuO nanoflowers (FT-Eu3+-CuO NF sensor). The peak current of pyrimethanil oxidation was elevated by the sensor due to the integration of appreciable electrochemical features of the modifier, which indicates the high ability of the modified electrode to enhance the sensitivity of pyrimethanil detection. The pyrimethanil sensor under the optimized setting had a broad linear dynamic range (0.001-800.0 µM) and a narrow limit of detection (0.18 nM). The practical applicability of the as-fabricated electrode was verified by sensing pyrimethanil in real samples; it also exhibited commendable specificity, stability and reproducibility.

Photocatalytic degradation of ciprofloxacin by MMT/CuFe2O4 nanocomposite: characteristics, response surface methodology, and toxicity analyses.

The photocatalytic degradation of ciprofloxacin (CIP) was examined by loading spinel ferrite copper (CuFe2O4) nanoparticles onto montmorillonite (MMT) under irradiation using UV light. The laboratory parameters were optimized using response surface methodology (RSM), and maximum efficiency (83.75%) was achieved at a pH of 3, CIP concentration of 32.5 mg/L, MMT/CuFe2O4 dose of 0.78 g/L, and irradiation time of 47.50 min. During the photocatalysis process, the experiments on radical trapping demonstrated the generation of hydroxyls (•OH), superoxide (•O2-) radical, electrons (e-), and holes (h+). A low rate drop (below 10%) in the CIP degradation during the six consecutive reaction cycles corroborated the remarkable recyclability and stability of the MMT/CuFe2O4. The acute toxicity of the treated solution was determined using Daphnia Magna, by applying photocatalysis, which was indicative of a marked decline in the toxicity. Comparing the findings of the degradation using UV and the degradation process using visible light represented results with close resemblance to each other at the end of the reaction time. Besides, under UV and visible light, the particles in reactor are easily activated when the pollutant mineralization exceeded 80%.

Challenges in the Management of Invasive Fungal Infections in the Middle East: Expert Opinion to Optimize Management Using a Multidisciplinary Approach.

Invasive fungal infection (IFI) is a significant global healthcare concern among critically ill and immunocompromised patients. In Middle Eastern countries, IFI has been steadily increasing among hospitalized patients in the past two decades. Diagnosis of IFI at an early stage is crucial for efficient management. Invasive fungal infection management is complex and requires the involvement of physicians from different specialties. There are several challenges associated with IFI management in the countries in the Middle East. This review aims to understand the key challenges associated with IFI management in the Middle East, encompassing epidemiology, diagnosis, therapeutic options, and optimizing a multidisciplinary approach. In addition, this review aims to incorporate expert opinions from multidisciplinary fields for optimizing IFI management in different Middle Eastern countries by addressing key decision points throughout the patient's journey. Lack of epidemiological data on fungal infections, slow and poorly sensitive conventional culture-based diagnostic tests, limited availability of biomarker testing, lack of awareness of clinical symptoms of the disease, limited knowledge on fungal infections, lack of local practice guidelines, and complicated disease management are the major challenges associated with IFI diagnosis and management in the Middle Eastern countries. Implementation of a multidisciplinary approach, antifungal stewardship, improved knowledge of fungal infections, the use of rapid diagnostic tests, and enhanced epidemiological research are warranted to lower the IFI burden in the Middle East.

Narrative Review of the Epidemiology of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia in Gulf Cooperation Council Countries.

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are the most common healthcare-associated infections, with rates varying between countries. Antimicrobial resistance (AMR) among common HAP/VAP pathogens has been reported, and multidrug resistance (MDR) is of further concern across Middle Eastern countries. This narrative review summarizes the incidence and pathogens associated with HAP/VAP in hospitals across Gulf Cooperation Council (GCC) countries. A PubMed literature search was limited to available data on HAP or VAP in patients of any age published within the past 10 years. Reviews, non-English language articles, and studies not reporting HAP/VAP data specific to a GCC country were excluded. Overall, 41 articles, a majority of which focused on VAP, were selected for inclusion after full-text screening. Studies conducted over multiple years showed a general reduction in VAP rates over time, with Gram-negative bacteria the most commonly reported pathogens. Gram-negative isolates reported across GCC countries included Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Rates of AMR varied widely among studies, and MDR among A. baumannii, K. pneumoniae, Escherichia coli, P. aeruginosa, and Staphylococcus aureus isolates was commonly reported. In Saudi Arabia, between 2015 and 2019, rates of carbapenem resistance among Gram-negative bacteria were 19-25%; another study (2004-2009) reported antimicrobial resistance rates in Acinetobacter species (60-89%), P. aeruginosa (13-31%), and Klebsiella species (100% ampicillin, 0-13% other antimicrobials). Although limited genotype data were reported, OXA-48 was found in ≥ 68% of patients in Saudi Arabia with carbapenem-resistant Enterobacteriaceae infections. Ventilator utilization ratios varied across studies, with rates up to 0.9 reported in patients admitted to adult medical/surgical intensive care units in both Kuwait and Saudi Arabia. VAP remains a burden across GCC countries albeit with decreases in rates over time. Evaluation of prevention and treatment measures and implementation of a surveillance program could be useful for the management of HAP and VAP.

Capability of copper-nickel ferrite nanoparticles loaded onto multi-walled carbon nanotubes to degrade acid blue 113 dye in the sonophotocatalytic treatment process.

In this study, copper-nickel ferrite (CuNiFe2O4) nanoparticles were successfully loaded onto multi-walled carbon nanotubes (MWCNTs) by using the coprecipitation method and used as new catalysts (MWCNT-CuNiFe2O4) in the sonophotocatalytic degradation process of the acid blue 113 (AB113) dye. The success of the MWCNT-CuNiFe2O4 synthesis and its properties were determined by analyzing it using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). A high efficiency of dye removal (100%), total organic carbon (93%), and chemical oxygen demand (95%) were achieved with the following conditions: pH of dye solution = 5, MWCNT-CuNiFe2O4 dosage = 0.6 g/L, AB113 dye concentration = 50 mg/L, UV light intensity = 36 W, ultrasonic wave frequency = 35 kHz, and treatment time = 30 min. The kinetic results revealed that the efficiency of the sonophotocatalytic process using MWCNT-CuNiFe2O4 was higher than that of the sonolysis, photolysis, photocatalysis, and sonocatalysis processes. Scavenging studies demonstrated that the holes (h+) and hydroxyl radical (•OH) were the main reactive species for the AB113 dye degradation. The stability and recyclability of MWCNT-CuNiFe2O4 were confirmed with eight consecutive cycles for a maximum efficiency of more than 92%. The high rate of BOD5/COD indicated that the sonophotocatalytic process had the potential to degrade the dye into degradable compounds. The toxicity study with an Escherichia coli growth inhibition rate emphasized that MWCNT-CuNiFe2O4 in the sonophotocatalytic degradation process of the AB113 dye had a significant effect on reducing toxicity, when compared to processes of photolysis and photocatalysis. During the sonophotocatalytic process using MWCNT-CuNiFe2O4, the AB113 dye was mineralized into CO2, H2O, NH4+, NO3-, and SO42-. The results of the present study proved that the MWCNT-CuNiFe2O4-based sonophotocatalytic process was a promising dye degradation technology to protect the aquatic environment.

Removal of Benzene and Toluene from Synthetic Wastewater by Adsorption onto Magnetic Zeolitic Imidazole Framework Nanocomposites.

Considering the risk associated with exposure to benzene and toluene in water resources, researchers have been motivated to conduct studies to remove them from aqueous solutions. Thus, by performing the present study, the potential of Fe3O4/zeolite imidazolate framework nanoparticles (Fe3O4@ZIF-8) was evaluated for the adsorption of benzene and toluene. Accordingly, the solution pH, Fe3O4@ZIF-8 dosage, mixing time, concentration of benzene and toluene, and temperature, were the parameters considered for conducting the batch experiments, for which their effect on adsorption efficiency was evaluated. Our conducted experiments introduced the neutral pH as the best pH range to obtain the maximum removal. Fitting the adsorption data into the various models revealed the aptness of the Langmuir isotherm equation in describing experimental information and highest adsorption capacity; for benzene it was 129.4, 134.2, 137.3, and 148.2 mg g-1, but for toluene it was 118.4, 125.2, 129.6, and 133.1 mg g-1, for temperature 20, 30, 40, and 50 °C, respectively. Using obtained optimal conditions, the adsorption efficiencies of benzene and toluene were obtained to be 98.4% and 93.1%, respectively. Kinetic studies showed acceptable coefficients for PSO kinetics and confirmed its suitability. Also, the recyclability results showed that for six consecutive periods of the adsorption-desorption process, the percentage of removal decreased by only 6% for benzene and toluene. Moreover, calculating thermodynamic parameter changes for benzene and toluene removal confirmed the favorability and spontaneity of the studied process and its endothermic nature. Considering the above findings, Fe3O4@ZIF-8 was found to be an operative adsorbent for removing pollutants.

Surgical and mediastinal emphysema in critically ill COVID-19 patients: A multicentric experience.

INTRODUCTION: Coronavirus illness 2019, commonly referred to as COVID-19, is a highly infectious disease brought on by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 was declared a universal pandemic in March 2020 by the World Health Organization and is a severe health issue with unprecedented morbidity and mortality rates. Both surgical and mediastinal emphysema have been seen in cases of critically ill COVID-19 patients in several hospitals in the Eastern Province of Saudi Arabia. METHODS: This was a retrospective, cross-sectional, multicentric study involving several hospitals in the Saudi Arabian Eastern Province. Data were collected from intensive care units (ICUs) in these hospitals from March 2 to August 2, 2020. The inclusion criteria consisted of all patients who tested positive for SARS-CoV-2 and were admitted to a critical care unit. RESULTS: Thirty patients required thoracic consultation and management, including 26 males (81.3%) and 4 females (12.5%) (1:0.15) who developed surgical and mediastinal emphysema requiring thoracic surgery intervention. Most of the patients were on high ventilation settings, and the mean duration of ventilator support was 16.50 ± 13.98 days. Two patients (6.3%) required reintubation. The median positive end-expiratory pressure (PEEP) was 12 ± 2.80 cmH2O with a median FiO2 of 70% ± 19.73. On average, thoracic complications occurred on day 3 (±6.29 days) postintubation. Ten patients (33.33%) experienced a pneumothorax associated with surgical emphysema (SE), 1 patient (3.33%) presented with only mediastinal emphysema; 17 patients (56.66%) with only SE, and 1 (3.33%) had mediastinal emphysema associated with SE. We noted a correlation between the duration of ventilator support, the length of ICU stay (P < 0.001), and the total length of stay (LOS) in the hospital (P < 0.001). Total length of hospital stay showed significant association with the onset of complications (P = 0.045) and outcomes (P = 0.006). A significant association between PEEP and the duration of ventilator support was also evident with a P value = 0.009 and the onset of complications (P = 0.043). In addition, we found a significant association between the group with pneumothorax in combination with SE, and their outcomes, with a P = 0.002. CONCLUSION: Surgical and mediastinal emphysema in the critically ill patients are usually attributed to barotrauma and high ventilations settings. During COVID-19 pandemic, these entities were seen and the pathogenesis was revisited and some attributed its presence to the disease process and destruction on lung parenchyma. The associated with extended LOS and delayed recovery in addition to poor prognosis were seen. Their presence is an indicator to higher morbidity and mortality.

COVID-19 vaccine had a significant positive impact on patients with SARS-COV-2 during the third (Omicron) wave in Saudi Arabia.

INTRODUCTION: The third (Omicron) wave had caused significant increase in the number of COVID-19 cases around the globe. The severity of the disease dependeds on the extent of the vaccination status. METHODS: This is a retrospective study of infected COVID-19 patients during the third (Omicron) wave in a hospital in Saudi Arabia. RESULTS: A total of 400 patients were included with 220 (55 %) males and 180 (45 %) females, and a mean age (+/- SD) of 36.34 + 16.47 years. The most common presenting symptoms were: sore throat 159 (39.8 %), cough 158 (39.5 %), fever 132 (33 %), headache 122 (30.5 %), and muscle ache 124 (31%). There was no difference in underlying conditions, signs and symptoms between males and females apart from the occurrence of sore throat with an OR of 2.014 (95 % CI: 1.103-3.677, P = 0.023) and need of hospitalization OR 2.457 (95 % CI: 1.168-5.167, P value =.018) in a binary logistic regression comparison. The need for hospitalization was inversely related to the number of COVID-19 vaccination doses. The rate of admission was 8 (72.7 %), 34 (12 %), 4 (5.4 %) for one, two, and three doses of COVID-19 vaccine, respectively (P < 0.0001). Of all the patients, 14 (3.5 %) and 8 (2 %) required intensive care (ICU) admission and mechanical ventilation, respectively. The median Ct-value of SARS-CoV-2 was higher in those who had 2 or 3 doses compared to those who had one dose of the COVID-19 vaccine, but the difference did not reach statistical significance. None of the included patients died during the study period. CONCLUSION: Omicron variant symptoms among infected patients are generally milder compared to other variants. Prior COVID-19 vaccination may limit disease severity and need for hospitalization.

Modeling the Potential Impact of Remdesivir Treatment for Hospitalized Patients with COVID-19 in Saudi Arabia on Healthcare Resource Use and Direct Hospital Costs: A Hypothetical Study.

BACKGROUND AND OBJECTIVES: Coronavirus disease 2019 (COVID-19) has spread rapidly worldwide. Saudi Arabia was significantly impacted by COVID-19. In March 2021, 381,000 cases were reported with 6539 deaths. This study attempts to quantify the impact of remdesivir on healthcare costs in Saudi Arabia, in terms of intensive care unit admissions, mechanical ventilation, and death prevention. METHODS: A forecasting model was designed to estimate the impact of remdesivir on the capacity of intensive care units and healthcare costs with patients requiring low flow oxygen therapy. The forecasting model was applied in the Saudi context with a 20-week projection between 1 February and 14 June, 2021. Model inputs were collected from published global and Saudi literature, available forecasting resources, and expert opinions. Three scenarios were assumed: the effective pandemic infection rate (Rt) remains at 1, the Rt increases up to 1.2, and the Rt declines from 1 to 0.8 over the study period. RESULTS: The model estimated that the use of remdesivir in hospitalized patients, in the optimistic and pessimistic scenarios, could prevent between 1520 and 3549 patient transfers to intensive care units and mechanical ventilation, prevent between 815 and 1582 deaths, and make potential cost savings between $US154 million and $US377 million owing to the reduction in intensive care unit capacity, respectively. CONCLUSIONS: The treatment with remdesivir may improve patient outcomes and reduce the burden on healthcare resources during this pandemic.

The Saudi Critical Care Society practice guidelines on the management of COVID-19 in the ICU: Therapy section.

BACKGROUND: The rapid increase in coronavirus disease 2019 (COVID-19) cases during the subsequent waves in Saudi Arabia and other countries prompted the Saudi Critical Care Society (SCCS) to put together a panel of experts to issue evidence-based recommendations for the management of COVID-19 in the intensive care unit (ICU). METHODS: The SCCS COVID-19 panel included 51 experts with expertise in critical care, respirology, infectious disease, epidemiology, emergency medicine, clinical pharmacy, nursing, respiratory therapy, methodology, and health policy. All members completed an electronic conflict of interest disclosure form. The panel addressed 9 questions that are related to the therapy of COVID-19 in the ICU. We identified relevant systematic reviews and clinical trials, then used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach as well as the evidence-to-decision framework (EtD) to assess the quality of evidence and generate recommendations. RESULTS: The SCCS COVID-19 panel issued 12 recommendations on pharmacotherapeutic interventions (immunomodulators, antiviral agents, and anticoagulants) for severe and critical COVID-19, of which 3 were strong recommendations and 9 were weak recommendations. CONCLUSION: The SCCS COVID-19 panel used the GRADE approach to formulate recommendations on therapy for COVID-19 in the ICU. The EtD framework allows adaptation of these recommendations in different contexts. The SCCS guideline committee will update recommendations as new evidence becomes available.

COVID-19-Induced Encephalitis: A Case Report of a Rare Presentation With a Prolonged Electroencephalogram.

Encephalitis is one of the rare complications of coronavirus disease 2019 (COVID-19) that can be missed and confused with other causes of encephalitis. There was a 36-year-old male known to have glucose-6 phosphate dehydrogenase deficiency, who was brought to the emergency department with fever and confusion of one-week duration. Altered mental status work-up, including cerebrospinal fluid analysis, was done and turned out to be nondiagnostic. Multiple prolonged video-electroencephalographic recordings were done and showed different abnormalities suggestive of encephalitis. The diagnosis of COVID-19-induced encephalitis was made by exclusion of other encephalitis-related etiologies in the presence of a positive COVID-19 polymerase chain reaction (PCR) test, and treatment was initiated accordingly. Over a period of three weeks, the patient showed progressive improvement and was discharged home with regular follow-up in the neurology clinic. Upon follow-up in the clinic, the patient was fully independent but with multiple abnormal electroencephalographic recordings showing generalized encephalopathy with no epileptic discharges.

Activated carbon derived from Azolla filiculoides fern: a high-adsorption-capacity adsorbent for residual ampicillin in pharmaceutical wastewater.

In this study, the effectiveness of activated carbon prepared from the Azolla filiculoides fern (ACAF) in order to remove ampicillin from aqueous solution was examined. The preparation of the ACAF was performed through chemical and physical activation processes with the presence of ZnCl2 and at a temperature of 450 °C. The ACAF yield was 44.7% of the fresh Azolla filiculoides. The results obtained from the characterization study indicate that the prepared ACAF has excellent surface and internal properties to be used as an adsorbent. The surface area, porosity, and pore volume were estimated to be 716.4 m2/g, 51.2%, and 0.621 cm3/g, respectively. The functional groups in ACAF that were responsible for the adsorption of ampicillin molecules were detected using FTIR analyses. The maximum efficiency (96.84%) and uptake (114.3 mg/g) of ACAF to remove ampicillin were achieved under the following conditions: ACAF dose = 0.8 g/L, pH = 7, concentration of ampicillin = 100 mg/L, contact time = 60 min, and temperature = 45 °C. It was found that the kinetic and isotherm data matched the pseudo-second-order and Langmuir models with high precision values, respectively. Considering the thermodynamics of the adsorption, the endothermic and spontaneous nature of the ampicillin adsorption onto ACAF was approved. The ampicillin adsorption capacity by ACAF was not significantly affected by the presence of different concentrations of NaNO3 competitor ion. The considerably higher adsorption capacity of the ACAF for ampicillin (114.3 mg/g) than other previously used adsorbents with excellent regeneration level (five cycles) depicts the superior performance of ACAF in the adsorption systems. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13399-021-01962-4.

The biosorption of reactive red dye onto orange peel waste: a study on the isotherm and kinetic processes and sensitivity analysis using the artificial neural network approach.

The agricultural waste of orange peels (OPs) was utilized as a cheap biosorbent and then tested for its ability to treat the reactive red (RR) dye wastewater. Several experiments were done to get the equilibrium isotherm and kinetic-relevant data. In addition, several experimental factors such as solution pH, temperature, contact time, and initial RR dye concentration were studied, in light of their impact on the biosorption process. The utilized isotherm and kinetic models were evaluated by using the chi-square test and coefficient of determination parameters for their representation of real data. In addition, the obtained data of their biosorption capacities, at different conditions, were modeled by the artificial neural network (ANN) approach. The results of the isotherm study revealed that the experimental data can be best accounted by both the Langmuir and Temkin models, demonstrating that the RR molecules were sorbed to two or more different types of biosorption sites of OP. The kinetic study for determining the characteristics of the rate of diffusion demonstrated that the intraparticle diffusion process was not the sole rate-limiting step in the biosorption of the RR dye-OP couple. Furthermore, the biosorption process was chemisorption in nature, as the pseudo-second-order reaction proved to be the best representative model for the kinetic data. The outcome of modeling also assumed that using the ANN tool was useful to reproduce the data again and foretell the manner in which biosorption behaved. According to the results of the Langmuir model, it was found that the maximum OP uptake for the biosorption of the RR dye was up to 82 mg/g, observed at optimized values of the experimental parameters. Such prior results highlight that OP is an effective agent of biosorption in the elimination of RR dyes from polluted solutions, moreover, in a cost-effective manner.

A seven-year surveillance of Candida bloodstream infection at a university hospital in KSA.

OBJECTIVES: Candidemia incidence has increased in the past few years, with high mortality. Previous studies have reported a variable distribution of Candida spp. among different regions. This study aimed to identify the species found in Candida bloodstream infections, routine antifungal susceptibility testing, and mortality outcomes in an academic medical centre. METHODS: Between January 2012 and December 2018, the positive blood cultures for candidemia infection were retrieved and statistically analysed for species prevalence, susceptibility pattern, and crude mortality at 14, 30, 60 and 90 days. RESULTS: Of 156 candidemia cases, a majority (69.2%) was caused by non-albicans Candida spp. After Candida albicans (30.8%), Candida tropicalis and Candida parapsilosis were the second and third most frequeunt isolates spp, each counting for 23.7%. Acquired resistance was detected in 14.8% of candidemia strains. No other antifungal resistance was detected. The overall crude mortality rates of all species were 29.3%, 47.9%, 56.4%, and 58.0% at 14, 30, 60, and 90 days, respectively. A higher mortality rate was noted in cases of Candida krusei infection (crude mortality 71.4-100%, p = 0.002). CONCLUSION: In this study, a considerable shift to non-albicans Candida causing most bloodstream infections was observed. As such infections pose a serious threat to hospitalised patients, microbiology laboratories are urged to adopt rapid diagnostic and minimal inhibitory concentration-based testing for the detection of susceptible dose-dependent phenotypes. Prospective studies are essential to consider the prognosis of bloodstream infections by various Candida species in a multivariate model.

The practical utility of the synthesis FeNi3@SiO2@TiO2 magnetic nanoparticles as an efficient photocatalyst for the humic acid degradation.

Humic acid (HA) compounds in drinking water and wastewater disinfection processes are viewed as precursors of highly toxic, carcinogenic, and mutagenic disinfection by-product chemicals. In recent times, these compounds have gained considerable attention of scientists for their successful removal from aqueous solutions to permissible limits. To achieve this aim, the present study investigated, for the first time, the photocatalytical performance of the synthesis FeNi3@SiO2@TiO2 nanoparticles for the HA degradation under different environmental conditions. The photocatalytic reactions were performed using ultraviolet (UV) radiation, whose intensity was fixed at 2500 µW/cm2 throughout the experimental study. The characterization study performed, using specific diagnostic techniques, revealed the presence of several good morphological, magnetic, and catalytic specifications of the synthesized nanoparticles. The use of the simplified form of the Langmuir-Hinshelwood equation sufficiently describes the experimental data of the HA kinetic degradation, as it shows a high coefficient of regression values. Furthermore, the complete HA degradation was reached under conditions of pH = 3; initial HA concentration = 10 mg/L; FeNi3@SiO2@TiO2 nanoparticles dosage = 0.01 g/L; and reaction time >30 min. Thus, the results obtained from this research suggested that the catalyst of FeNi3@SiO2@TiO2 nanoparticles was an attractive, novel, and effective agent, which could be used for the degradation of HA in the photocatalytic processes.

A comprehensive study on the application of FeNi3@SiO2@ZnO magnetic nanocomposites as a novel photo-catalyst for degradation of tamoxifen in the presence of simulated sunlight.

Pharmaceutical compounds at trace concentrations are found in the environment, especially in drinking water and food, posing significant negative effects on humans as well as on animals. This paper aimed to examine the diagnostic catalytic properties and efficacy of a novel synthesized photocatalyst, namely FeNi3@SiO2@ZnO magnetic nanocomposite, for the removal of tamoxifen (TMX) from wastewater under simulated sunlight. According to the results, it was found that TMX was completely degraded operating under optimized conditions (i.e. pH = 7, catalyst dose = 0.01 g/L, initial TMX concentration = 20 mg/L and reaction time = 60 min). The reaction kinetics of TMX degradation followed a pseudo-first order kinetics model. The final by-products from the TMX photodegradation were water, carbon dioxide, acetic acid, nitroacetic acid methyl ester, 2-methyl-2-pentenal, and 4-methyl-2-pentanol. In addition, the synthesized photocatalyst could successfully performed five consecutive photodegradation cycles. The obtained results revealed that the synthesized FeNi3@SiO2@ZnO magnetic nanocomposite holds a great potential to be applied as a photocatalyst for the degradation of TMX on an industrial scale.

A comparative study of using barberry stem powder and ash as adsorbents for adsorption of humic acid.

In the present research, investigation of the practical utility of barberry stem powder (BSP) and barberry stem ash (BSA) for humic acid (HA) removal from an aqueous medium by adsorption was carried out. The adsorption process was tested by varying of pH (3-11), reaction time (5-20 min), initial HA concentration (5-40 mg/L), adsorbent dosage (1-4 g/L), and temperature (15-35 °C). The isothermal results revealed that the adsorption process is favorable for both used adsorbents and it is highly described using the Freundlich and Langmuir models (R2 > 0.960). Also, the maximum uptakes of BSP and BSA for HA were 20.220 and 16.950 mg/g at the abovementioned optimized conditions (pH = 7, reaction time = 10 min, temperature = 15 °C, initial HA concentration = 40 mg/L, and adsorbent amount = 1.0 g/L), respectively. The results achieved from the fitting of the experimental data with Dubinin-Radushkevich isotherm model showed that the HA molecules are adsorbed onto the BSP and BSA by physiosorption process. From the thermodynamic study, it appeared that the biosorption process of the HA onto two studied adsorbents was of exothermic nature. The kinetics of the adsorption process of HA has been found to be pseudo-second-order model (R2 = 0.930-0.999). Thus, the results obtained from this paper elucidated that the BSP exhibited higher adsorption capacity in comparison to BSA, for HA removal up to permissible concentrations.