Multienzyme Mimicking Cascade Mn3O4 Catalyst to Augment Reactive Oxygen Species Elimination and Colorimetric Detection: A Study of Phase Variation upon Calcination Temperature.

Over decades, nanozyme has served as a better replacement of bioenzymes and fulfills most of the shortcomings and intrinsic disadvantages of bioenzymes. Recently, manganese-based nanomaterials have been highly noticed for redox-modulated multienzyme mimicking activity and wide applications in biosensing and biomedical science. The redox-modulated multienzyme mimicking activity was highly in tune with their size, surface functionalization, and charge on the surface and phases. On the subject of calcination temperature to Mn3O4 nanoparticles (NPs), its phase has been transformed to Mn2O3 NPs and Mn5O8 NPs upon different calcination temperatures. Assigning precise structure-property connections is made easier by preparing the various manganese oxides in a single step. The present study has focused on the variation of multienzyme mimicking activity with different phases of Mn3O4 NPs, so that they can be equipped for multifunctional activity with greater potential. Herein, spherical Mn3O4 NPs have been synthesized via a one-step coprecipitation method, and other phases are obtained by direct calcination. The calcination temperature varies to 100, 200, 400, and 600 °C and the corresponding manganese oxide NPs are named M-100, M-200, M-400, and M-600, respectively. The phase transformation and crystalline structure are evaluated by powder X-ray diffraction and selected-area electron diffraction analysis. The different surface morphologies are easily navigated by Fourier transform infrared, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy analysis. Fortunately, for the mixed valence state of Mn3O4 NPs, all phases of manganese oxide NPs showed multienzyme mimicking activity including superoxide dismutase (SOD), catalase, oxidase (OD), and peroxidase; therefore, it offers a synergistic antioxidant ability to overexpose reactive oxygen species. Mn3O4 NPs exhibited good SOD-like enzyme activity, which allowed it to effectively remove the active oxygen (O2•-) from cigarette smoke. A sensitive colorimetric sensor with a low detection limit and a promising linear range has been designed to detect two isomeric phenolic pollutants, hydroquinone (H2Q) and catechol (CA), by utilizing optimized OD activity. The current probe has outstanding sensitivity and selectivity as well as the ability to visually detect two isomers with the unaided eye.

The Impact of Air Pollution on Asthma Severity among Residents Living near the Main Industrial Complex in Oman: A Cross-Sectional Study.

BACKGROUND: Asthma is a widespread chronic respiratory disease that poses a significant public health challenge. The current study investigated the associations between air pollution and asthma severity among individuals residing near the Sohar industrial port (SIP) in Oman. Despite the presence of multiple major industrial complexes in Oman, limited knowledge regarding their impact on respiratory health is accredited. Hence, the primary objective of this study is to offer valuable insights into the respiratory health consequences of industrial air pollution in Al Batinah North. METHODS: The state health clinics' records for patient visits related to asthma were collected for the timeframe spanning 2014 to 2022. Exposure was defined as the distance from the SIP, Majan Industerial Area (MIA), and Sohar Industerial Zone (SIZ) to determine high-, intermediate-, and low-exposure zones (<6 km, 6-12 km and >12 km, respectively). Exposure effect modifications by age, gender, and smoking status were also examined. RESULTS: The conducted cross-sectional study of 410 patients (46.1% males and 53.9% females) living in over 17 areas around SIP revealed that 73.2% of asthmatics were under 50 years old, with severity significantly associated with closeness to the port. Risk ratios were estimated to be (RR:2.42; CI95%: 1.01-5.78), (RR:1.91; CI95%: 1.01-3.6), and (RR:1.68; CI95%: 0.92-3.09) for SIP, MIP, and SIZ areas, respectively, compared to the control area. Falaj Al Qabail (6.4 km) and Majees (6 km) had the highest number of asthma patients (N 69 and N 72) and highest percentages of severe asthma cases among these patients (28% and 24%) with significant risk ratios (RR:2.97; CI95%: 1.19-7.45 and RR:2.55; CI95%: 1.00-6.48), correspondingly. Moreover, severe asthma prevalence peaked in the 25-50 age group (RR:2.05; CI95%: 1.26-3.33), and this linkage between asthma and age was much more pronounced in males than females. Smoking and exposure to certain contaminants (dust and smoke) also increased the risk of severe asthma symptoms, but their effects were less important in the high-risk zone, suggesting much more important risk factors. A neural network model accurately predicted asthma risk (94.8% accuracy), with proximity to SIP as the most influential predictor. CONCLUSIONS: This study highlights the high asthma burden near SIP, linked to port proximity, smoking, and wind direction as major risk factors. These findings inform vital public health policies to reduce air pollution and improve respiratory health in the region, prompting national policy review.

Synthesis of Spherical Mn2O3 Nanozymes from Different Green Precursors for their Innovative Applications in Catalytic Properties and Bioactivity.

Here, spherical Mn2O3 nanozymes were synthesized via a one-step green method using different green precursors, and their physicochemical properties and biological activities were monitored with various green precursors. Powder X-ray diffraction (PXRD) was performed to determine the crystalline properties and phases involved in the formation of cubic Mn2O3 nanozymes. The synthesized nanozymes were spherical and examined by SEM and FESEM studies. All of the samples synthesized using different green precursors exhibited different sizes but similar spherical shapes. Moreover, all green-synthesized nanozymes catalyzed the oxidation reaction of the chromogenic substrate 3,3'5,5' tetramethylbenzidine (TMB) in the absence of H2O2, and A2 (lemon-mediated Mn2O3 nanozymes), which the followed Michaelis-Menten kinetics, showed the best activity. Therefore, A2 (lemon-mediated nanozyme) showed oxidase-mimicking activity with distinct Km and Vmax values calculated by the Lineweaver-Burk plot. Furthermore, the current nanozymes demonstrated a significant ability to kill both Gram-negative and Gram-positive bacteria as well as effectively destroy biofilms under physiological conditions. Moreover, the green-mediated nanozymes also displayed ROS-scavenging activity. Our nanozymes exhibited scavenging activity toward OH and O2-• radicals and metal chelation activity, which were investigated colorimetrically. Therefore, these nanozymes might be used as effective antibacterial agents and also for the consumption of reactive oxygen species.

Phase variation of manganese oxide in the MnO@ZnO nanocomposite with calcination temperature and its effect on structural and biological activities.

Having powerful antibacterial and antioxidant effects, zinc oxide and manganese oxide nanomaterials are of great interest. Here we have synthesized manganese oxide decorated zinc oxide (MZO) nanocomposites by co-precipitation method, calcined at different temperatures (300-750 °C) and studied various properties. Here the crystalline structure of the nanocomposite and phase change of the manganese oxide are observed with calcination temperature. The average crystalline size increases and the dislocation density and microstrain decrease with the increase in calcined temperature for the same structural features. The formation of composites was confirmed by XRD pattern and SEM images. EDAX spectra proved the high purity of the composites. Here, different biological properties change with the calcination temperature for different shapes, sizes and structures of the nanocomposite. Nanomaterial calcined at 750 °C provides the best anti-microbial activity against Escherichia coli, Salmonella typhimurium, Shigella flexneri (gram-negative), Bacillus subtilis and Bacillus megaterium (gram-positive) bacterial strain at 300 µg/mL concentration. The nanomaterial with calcination temperatures of 300 °C and 450 °C provided better antioxidant properties.

Factors associated with anemia among school-going adolescents aged 10-17 years in Zanzibar, Tanzania: a cross sectional study.

BACKGROUND: Anemia among adolescents (ages 10-19 years) is a leading cause of morbidity and mortality in low- and middle-income countries and carries long-term health and economic consequences. To address the issue, policymakers and programmers require evidence of the burden of anemia among adolescents in specific contexts, as well as an understanding of the factors associated with anemia in this population. METHODS: We conducted a cross-sectional survey as a baseline assessment to determine the prevalence and factors associated with anemia in secondary school students, as part of a cluster-randomized effectiveness trial testing different micronutrient supplementation strategies in addressing anemia among adolescents in Zanzibar. Between March 7th to 25th, 2022 the survey was conducted on 2,479 school-going adolescents aged 10-17 years from 42 schools on the island of Zanzibar, Tanzania. Hemoglobin concentration was measured along with the collection of socio-demographics, health, food frequency, and water, sanitation and hygiene data. RESULTS: Based on the World Health Organization cutoffs for anemia, 53.3% of the sample had anemia (mild, moderate, or severe). Using chi-square tests and logistic regressions, we determined that females had higher odds of anemia than males (Adjusted OR = 1.47; 95% CI: 1.24, 1.74), those in the highest wealth quintile had lower odds of anemia than those in the lowest wealth quintile (Adjusted OR = 0.7; CI: 0.54, 0.91), stunted adolescents had higher odds of anemia than non-stunted students (Adjusted OR = 1.38; 95% CI: 1.06,1.81), and those who used shared toilets had higher odds of moderate or severe anemia than those with private toilet access (Adjusted OR = 1.68; CI: 1.07, 2.64). CONCLUSIONS: The high prevalence of anemia in this sample indicates an urgent need to address anemia among adolescents in Zanzibar, and the factors associated with anemia point to the importance of water, sanitation, and hygiene interventions in addition to dietary and nutritional support. TRIAL REGISTRATION: NCT05104554, registered 03/11/2021.

A 21-Year-Old Man with Previous History of Gastrectomy, Cholecystectomy, and Biliary Stenting with Failed Non-Operative Management of Blunt Trauma to the Liver Due to Traumatic Stent Perforation.

BACKGROUND Conservative management of blunt trauma to the liver is commonly used when there are no immediate signs of rupture or hemorrhage, but requires patient monitoring. The rate of failure for non-operative management ranges is 3-15%. This report is of a 21-year-old man with a previous history of gastrectomy, cholecystectomy, and biliary stenting with failed non-operative management of blunt trauma to the liver following a motor vehicle crash, due to traumatic stent perforation. CASE REPORT The patient reported abdominal pain and had positive FAST for fluid in the hepatorenal space. CT abdomen showed grade 3 hepatic injury and a common bile duct stent. He was resuscitated and admitted to the ICU. He developed escalating abdominal pain and tachycardia without hypotension. Repeat CT demonstrated a paraduodenal gas bubble. He underwent exploratory laparotomy, during which the following were found: hemoperitoneum, no active bleeding, a 3-cm blue stent exiting the left hepatic duct surrounded by a fibrous tract, and bile spilling from around the stent. The protruding portion of the stent was resected, the was tract oversewn, and the abdomen was closed. Once stabilized, the patient underwent ERCP with removal of the remaining stent segment. The postoperative course was complicated by surgical wound infection and fascial dehiscence managed operatively and with local wound care, and deep-space infections managed by interventional radiology drainage. CONCLUSIONS Blunt trauma injury of the liver can be successfully managed conservatively. However, this case highlights the importance of knowledge of the patient's medical history and the presence of biliary stents, which can result in traumatic biliary perforation with an intact liver.

Fe-Mn nanocomposites doped graphene quantum dots alleviate salt stress of Triticum aestivum through osmolyte accumulation and antioxidant defense.

An investigation was carried out to evaluate the effect of graphene quantum dots (GQD) and its nanocomposites on germination, growth, biochemical, histological, and major ROS detoxifying antioxidant enzyme activities involved in salinity stress tolerance of wheat. Seedlings were grown on nutrient-free sand and treatment solutions were applied through solid matrix priming and by foliar spray. Control seedlings under salinity stress exhibited a reduction in photosynthetic pigment, sugar content, growth, increased electrolyte leakage, and lipid peroxidation, whereas iron-manganese nanocomposites doped GQD (FM_GQD) treated seedlings were well adapted and performed better compared to control. Enzymatic antioxidants like catalase, peroxidase, glutathione reductase and NADPH oxidase were noted to increase by 40.5, 103.2, 130.19, and 141.23% respectively by application of FM_GQD. Histological evidence confirmed a lower extent of lipid peroxidation and safeguarding the plasma membrane integrity through osmolyte accumulation and redox homeostasis. All of these interactive phenomena lead to an increment in wheat seedling growth by 28.06% through FM_GQD application. These findings highlight that micronutrient like iron, manganese doped GQD can be a promising nano-fertilizer for plant growth and this article will serve as a reference as it is the very first report regarding the ameliorative role of GQD in salt stress mitigation.

Label-Free Detection of Epinephrine Using Flower-like Biomimetic CuS Antioxidant Nanozymes.

A biosensor comprising crystalline CuS nanoparticles (NPs) was synthesized via a one-step simple coprecipitation route without involvement of a surfactant. The powder X-ray diffraction method has been used to evaluate the crystalline nature and different phases consist of the formation of CuS NPs. Mainly hexagonal unit cells consist of the formation of CuS NP unit cells. Most of the surfaces are covered with rhombohedral microparticles with a smooth exterior and surface clustering, examined by SEM images, and the shape of NPs was spherical, having an average size of 23 nm, as confirmed by TEM analysis. This study has focused on the peroxidase-mimicking activity, superoxide dismutase (SOD)-mimicking activity, and chemosensor-based colorimetric determination and detection of epinephrine (EP) neurotransmitters with excellent selectivity. The CuS NPs catalyzed the oxidation of the oxidase substrate 3, 3-5, 5 tetramethyl benzidine (TMB) with the help of supplementary H2O2 that followed Michaelis-Menten kinetics with excellent Km and Vmax values calculated by the Lineweaver-Burk plot. Taking advantage of the drop in absorbance upon introduction of EP for the CuS NPs-TMB/H2O2 system, a colorimetric route has been developed for selective and real-time detection of EP. The sensitivity of the new colorimetric probe was vibrant, having a linear range of 0-16 µM, and achieved a low limit of detection of 457 nM. Moreover, the present nanosystem exhibited appreciable SOD-mimicking activity which could effectively remove O2•- from commercial cigarette smoke, along with it acting as a potential radical scavenger as well. The new nanosystem effectively scavenged •OH, O2.-, and metal chelation which were investigated calorimetrically.

Evaluating Biological Properties of Stingless Bee Propolis.

The aim of the present study was to determine the content of phenolics, flavonoids and tannins, as well as the biological functions of propolis extracts from the stingless bee (Heterotrigona itama). The raw propolis was extracted via maceration with ultrasonic pretreatment in 100% water and 20% ethanol. The yield of ethanolic propolis extracts was about 1% higher than its aqueous counterpart. The colorimetric assays showed that the ethanolic propolis extract had about two times higher phenolics (17.043 mg GAE/g) and tannins (5.411 mg GAE/g), and four times higher flavonoids (0.83 mg QE/g). The higher phenolic content had enhanced the antiradical and antibacterial capacities of the ethanolic extract. The propolis extracts significantly exhibited higher antibacterial activity against gram-positive bacteria (Staphylococcus aureus) than gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). However, aqueous extract was found to have a higher anticancer property based on the viability of lung cancer cells. No cytotoxic effect was observed on normal lung cells as the cell viability was maintained >50%, even the concentration of propolis extracts were increased up to 800 µg/mL. Different chemical compositions of propolis extract would show different bioactivities depending upon the individual applications. The high content of phenolics suggests that the propolis extract could be a natural source of bioactive ingredients for the development of innovative and functional foods.

Quality Attributes of Cold-Stored Khalal Barhi Dates Treated with Guava Leaf Extract and/or Lactic Acid as Natural Preservatives.

The use of natural ingredients to preserve the quality of fresh fruits is a promising approach to healthier products and a more sustainable industry. The present study was carried out to assess the effect of lactic acid (LA) and guava leaf extract (GLE) as natural preservatives on the quality parameters of Khalal Barhi dates. Physicochemical properties, antioxidant activity, color parameters, firmness, sensory properties, and yeast and mold counts of date fruits were evaluated during five weeks of storage at 4 ± 1 °C. The bioactive compounds in GLE were estimated by HPLC, which exhibited that GLE contains significant amounts of bioactive compounds, mainly, phenolics and flavonoids. With prolonged storage, the moisture content decreased, while the total soluble solids (TSS) increased in all samples. Similarly, a slight decrease in the pH with a concomitant increase in titratable acidity (TA) was observed throughout the storage. Generally, the samples treated with natural preservatives revealed lower changes in moisture content, TSS, pH, and TA than the control. The results exhibited decreased total phenolic content (TPC) and antioxidant activity for all samples with extended storage. The GLE and LA + GLE treatments significantly (p < 0.05) increased TPC and antioxidant activity on day 0 and preserved higher values of both during storage. Additionally, a decrease in the L* and b* values with an increase in the a* values of all samples was observed with advancement of storage. The LA + GLE treatment minimized the changes in color parameters and maintained higher firmness values during storage. Similarly, the sensory properties of all samples decreased with prolonged storage, but insignificant (p > 0.05) differences were found among the samples. Dipping treatments inhibited microbial growth over time, with the lowest yeast and mold counts achieved by the LA + GLE treatment. It can be concluded that the LA + GLE treatment has a protective effect on Khalal Barhi dates by minimizing post-harvest changes and decreasing the microbial load.