Eco-friendly anti-corrosion performance of chitosan modified with fused heterocyclic compound on mild steel in acidic medium.

This study aims to explore the prevention of chitosan modified with a fused heterocyclic compound as a sustainable corrosion inhibitor for mild steel in 1 M HCl. Electrochemical instruments, including potentiodynamic polarization techniques, and electrochemical impedance spectroscopy (EIS), were employed to evaluate the corrosion protection performance. The outcomes showed that the chitosan modified with a fused heterocyclic compound has outstanding inhibition performance, with an inhibition effectiveness of 98.25 % at 100 ppm. The anti-corrosion features of modified chitosan were ascribed to the presence of hetero atoms in modified chitosan composite which leads to the creation of a protective layer, The modified chitosan composite behaved as mixed-typed inhibitors, as shown by the PDP results. The modified chitosan composite adsorbs on mild steel in the investigated corrosive media via chemisorption interactions, and its adsorption followed the Langmuir adsorption model. Furthermore, increasing the temperature from 303 to 333 K enhanced the corrosion rate, most likely due to the desorption of the inhibitor agent from the steel surface.

Facile synthesis of MOF-derived N doped ZnO/C nanoparticles and its adsorption activity toward dye removal.

Metal-organic framework (MOF)-derived materials have gained an increasing interest and showed potential adsorption features in numerous applications. Significant attempts have been performed to boost the structure, functionality, surface area and porosity in addition to adsorption performance of MOF-derived carbon nanoparticles. Here, nitrogen-doped ZnO/carbon nanoparticles were synthesized by directly pyrolysis of Zn based metal organic framework (ZIF-8) in a nitrogen atmosphere at two different temperatures (600 and 800 °C), followed by chemical impregnation with ZnCl2 solution with ratio (10:1) wt/wt, and thermal activation at 500 °C for 1 h. SEM, TEM, XPS, nitrogen adsorption-desorption method, and TGA characterization techniques were employed to investigate the morphology and structure characteristics. Then, thorough analysis of N doped ZnO/C-(600 and 800), adsorption capacity to remove Remazol brilliant blue reactive (RBBR) dye from aqueous phase was conducted. At room temperature, the porous N doped ZnO/C with high surface area attained a maximum adsorption capacity about 49.3 mg/g and demonstrated a strong adsorption capacity toward RBBR dye. The insights of kinetic, thermodynamic and adsorption isotherm studies of the as-demonstrated samples open up more discussion for MOFs-derived carbon adsorbents for wastewater treatment.

Insight into TEMPO-oxidized cellulose-based composites as electrochemical sensors for dopamine assessment.

The diagnosis and treatment of many neurological and psychiatric problems depend on establishing simple, inexpensive, and comfortable electrochemical sensors for dopamine (DA) detection. Herein, 2,2,6,6 tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOC) were successfully loaded with silver nanoparticles (AgNPs) and/or graphite (Gr) and crosslinked by tannic acid, producing composites. This study describes a suitable casting procedure for the composite synthesis of TOC/AgNPs and/or Gr for the electrochemical detection of dopamine. Electrochemical impedance spectra (EIS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the TOC/AgNPs/Gr composites. In addition, the direct electrochemistry of electrodes treated with the prepared composites was examined using cyclic voltammetry. The TOC/AgNPs/Gr composite-modified electrode improved electrochemical performance towards detecting dopamine compared to TOC/Gr-modified electrodes. Upon employing amperometric measurement, our electrochemical instrument has a wide linear range (0.005-250 µM), a low limit of detection (0.0005 µM) at S/N = 3, and a high sensitivity (0.963 µA µM-1 cm-2). Additionally, it was demonstrated that DA detection seemed to have outstanding anti-interference characteristics. The proposed electrochemical sensors meet the clinical criteria regarding reproducibility, selectivity, stability, and recovery. The straightforward electrochemical method utilized in this paper may provide a potential framework for creating dopamine quantification biosensors.

Polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly (AM-co-ECA-co-AMPS): Broadband dielectric spectroscopy investigations.

In this study, the dielectric behavior of polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly(AM-co-ECA-co-AMPS) was investigated by broadband dielectric spectroscopy (BDS). The dielectric spectra obtained from -70 to 70 °C showed a superposition of three distinctive processes, electrode polarization, charge carrier's transport, and a molecular relaxation process. These dynamic processes were further analyzed along with the effect of both temperature and reduced graphene oxide (rGO) content. The development of a clear electrochemical double layer (ECDL) at the electrode/hydrogel interface strongly supports its possible application in supercapacitors' forms of energy storage. TGA, DSC, rheology, and electrochemical properties were studied. Furthermore, when the composite hydrogel with rGO content of 2.5 % was assembled into a symmetric supercapacitor, it displayed a specific capacitance of 756 F.g-1 at 1 A.g-1 and 704 F.g-1 after 5000 cycles with high capacitance retention of 93.2 %. The superior conductivity and porous structure of the rGO composite hydrogel are credited with the hydrogel's excellent electrochemical capabilities.

Green and sustainable chitosan-gum Arabic nanocomposites as efficient anticorrosive coatings for mild steel in saline media.

The application of green and sustainable anticorrosive coatings is becoming of upsurge interest for the protection of metallic materials in aggressive environments. Herein, a stable crystalline chitosan/gum Arabic composite (CGAC) nanopowder was successfully synthesized and characterized by various methods. The CGAC nanopowder with different doses (25, 50, 100, and 200 ppm) was used to coat mild steel samples and examined its anticorrosion ability in 3.5 wt.% NaCl solution using gravimetric, electrochemical measurements, and surface characterization techniques. All methods yielded consistent results revealing that nanocomposite coatings can impart good anticorrosive properties to the steel substrate. The obtained protection efficiency was enhanced with increasing CGAC dose in the applied surface layer achieving 96.6% for the 200 ppm-coating. SEM and AFM surface morphologies of uncoated and coated samples after the inundation in the saline solution showed that CGAC coating can block the active corrosive sites on the steel surface, and prevent the aggressive Cl- ions from attacking the metallic substrate. The water droplet contact angle gave further support as it increased from 50.7° for the pristine uncoated surface to 101.2° for the coated one. The current research demonstrates a promising natural and reliable nanocomposite coating for protecting mild steel structures in the marine environment.

High performance hydrogel electrodes based on sodium alginate-g-poly(AM-c o-ECA-co-AMPS for supercapacitor application.

Electrochemical conductive hydrogels are being extensively explored in the fabrication of portable batteries and high-performance supercapacitors. Herein, the rational design of a new polyanionic electrically conductive hydrogels based on sodium alginate-g-poly(AM-co-ECA-co-AMPS) are described. rGO was incorporated into the hydrogel during the polymerization process generating rGO@ sodium alginate-g-poly(AM-co-ECA-co-AMPS) composite hydrogels to study the impact of rGO on the performance of the hydrogels. FT-IR, XRD, and SEM-EDX characterized the chemical composition, crystalline, and morphological structure of the new synthesized hydrogels. The electrochemical performance of as-synthesized hydrogels was investigated by cyclic voltammetry, galvanostatic, charge-discharge rate, and electrochemical impedance spectroscopy. The supercapacitor performance for ECH2.5 composite hydrogel showed a capacitance of 753 F. g-1 at 1 A. g-1 with good rate capability and cycling stability up to 5000 cycles. Thus, ECH2.5 hydrogel is a good candidate as electrode material in supercapacitor applications.

Comparison of citation rates between Covid-19 and non-Covid-19 articles across 24 major scientific journals.

Covid-19 has been front and center in the global landscape since the beginning of 2020. In response, the scientific field has dedicated enormous amounts of resources to researching the virus and its effects. The number of times Covid-19 publications are being cited throughout the literature appears remarkably high but has not been directly compared to non-Covid-19 papers in the same journals over an extended period. In our study, we use Clarivate's Web of Science-Science Citation Index Expanded™ database to identify Covid-19 papers published in 24 major scientific journals over a period of 24 months from January 1, 2020 to December 31, 2021. We conduct our search using keywords "Covid-19", "coronavirus", and "sars-cov-2" to locate publications with these words in the title. We then quantify the number of citations these papers have received and compare rates to non-Covid-19 papers in the same journals over the same timeframe. We find that, across 24 open-access and subscription-based scientific journals, Covid-19 papers published in the past 2 years currently have a median citation rate of 120.79 compared to 21.63 for non-Covid-19 papers. When negative binomial regression is used to minimize the influence of other variables such as article number variation and field of research, Covid-19 papers have still experienced more than 80% increase in citations relative to non-Covid-19 papers. These novel findings demonstrate that Covid-19 papers are being cited at remarkably higher rates than non-Covid-19 articles contained within the same journals. This suggests that journal impact factor, which is a product of the number of citations that recently published articles receive, will likely be drastically influenced by the number of Covid-19 papers that a journal has included within its pages in the previous years.

Green and facile synthesis of nickel oxide-porous carbon composite as improved electrochemical electrodes for supercapacitor application from banana peel waste.

Lithium-ion batteries and supercapacitors are examples of energy storage technologies that have a lot of promise in a variety of applications. Herein, NiO-porous carbon composites were prepared by a green and cost-effective facile synthesis route from banana peel waste materials. The surface morphology and chemical composition of the NiO-porous carbon composite were investigated using a scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX). The prepared samples were also described through Fourier transform infrared (FTIR) spectroscopy, x-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), and surface area measurements. The electrochemical behavior of prepared materials was studied by cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance (EIS) to test their applicable suitability as supercapacitor electrode. PC-NiO (3) composite exhibits a remarkable specific capacitance of 811 F/g at a current density of 1 A/g. The specific capacitance of PC-NiO (3) is 5.3 times more than that of PC material at 1.0 A/g. Furthermore, the PC-NiO (3) composite material still exhibits a specific capacitance of 780 F/g at 5.0 A/g, high rate capability of 84.55% retention at a high current density of 10.0 A/g and superior cycle stability at 1000 cycles. Based on its high specific capacitance, the NiO-porous carbon nanocomposite is one of the most promising electrode materials for supercapacitors, according to the above results.

Environmentally benign corrosion inhibitors based on cellulose niacin nano-composite for corrosion of copper in sodium chloride solutions.

There is a high demand for high performance, effective and eco-friendly corrosion inhibitors for industrial applications. Therefore, novel benign high performance corrosion inhibitors based on biopolymer were synthesized in-situ using different cellulosic materials and niacin. Characterization of the cellulose nano-composite was carried out by Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The anticorrosive performance of cellulose composites for copper in 3.5% NaCl solutions were evaluated using polarization and electrochemical impedance spectroscopy (EIS) techniques. Surface morphology of uninhibited and inhibited composites was studied using SEM and EDX. Potentiodynamic polarization measurements confirmed that cellulose based inhibitors act as a mixed type inhibitor. The inhibition efficiency of ethyl cellulose-niacin composite (NEC) was 94.7% outperforms those of microcrystalline cellulose-niacin composite (NMCC) and carboxymethyl cellulose-niacin composite (NCMC) which were 33.2 and 83.4%, respectively, as green corrosion inhibitors for Copper in 3.5% NaCl solutions. The data extracted from EIS were fitted through an equivalent circuit to model the corrosion inhibition.

Mathematical modeling for bioprocess optimization of a protein drug, uricase, production by Aspergillus welwitschiae strain 1-4.

Microbial uricase is effective protein drug used to treat hyperuricemia and its complications, including chronic gout, also in prophylaxis and treatment of tumor lysis and organ transplants hyperuricemia. Uricase is commonly used as diagnostic reagent in clinical analysis for quantification of uric acid in blood and other biological fluids. Also, it can be used as an additive in formulations of hair coloring agents. A newly isolated strain, Aspergillus sp. 1-4, was able to produce extracellular uricase on a medium containing uric acid as inducer. Phylogenetic analysis based on ITS region sequence analysis and phenotypic characteristics showed that Aspergillus sp. strain 1-4 is closely related to Aspergillus welwitschiae and its nucleotide sequence was deposited in the GenBank database and assigned sequence accession number MG323529. Statistical screening using Plackett-Burman design with 20 runs was applied to screen fifteen factors for their significance on uricase production by Aspergillus welwitschiae. Results of statistical analysis indicated that incubation time has the most significant positive effect on uricase production followed by yeast extract and inoculum size with the highest effect values of 13.48, 5.26 and 4.75; respectively. The interaction effects and optimal levels of these factors were evaluated using central composite design. The maximum uricase production was achieved at incubation time (5 days), yeast extract (2 g/L) and inoculum size (4 mL/50 mL medium) are the optimum levels for maximum uricase production (60.03 U/mL). After optimization, uricase production increased by 3.02-folds as compared with that obtained from the unoptimized medium (19.87 U/mL).

Assessment of knowledge of obstetric danger signs among pregnant women attending a teaching hospital.

INTRODUCTION: Knowledge of obstetric danger signs among pregnant women is of paramount importance in improving maternal, and fetal health outcomes. This study aims to determine the knowledge of danger signs among pregnant women seeking antenatal care in a teaching hospital. MATERIALS AND METHODS: A cross-sectional study was carried out for two months among pregnant women who visited the antenatal clinic of a teaching hospital. A pre-tested and pre-designed proforma was used. Mean knowledge scores were computed and knowledge was classified into adequate and inadequate. RESULTS: A total of 170 pregnant women fulfilling the inclusion criteria were included. Mean age of the study participants was found to be 26.40 ± 4.14 years. Nearly 67.10% were aware of bleeding per vagina being a danger sign, 50.0% stated excessive vomiting as a danger sign, 23.50% knew that blurring of vision was a danger, while a mere 20.0% reported that convulsions were a danger sign. Overall, adequate knowledge (total knowledge score of 5 and above) was observed in 54.70% of the participants. CONCLUSION: Majority of the study participants had adequate knowledge of danger signs in pregnancy. However, when knowledge about specific individual danger signs were further assessed, a high proportion had very poor knowledge. The mean knowledge scores were found to be low.

Value added by Spirulina platensis in two different diets on growth performance, gut microbiota, and meat quality of Japanese quails.

AIM: The growth promoting effect of the blue-green filamentous alga Spirulina platensis (SP) was observed on meat type Japanese quail with antibiotic growth promoter alternative and immune enhancing power. MATERIALS AND METHODS: This study was conducted on 180 Japanese quail chicks for 4 weeks to find out the effect of diet type (vegetarian protein diet [VPD] and fish meal protein diet [FMPD])- Spirulina dose interaction (1 or 2 g/kg diet) on growth performance, gut microbiota, and sensory meat quality of growing Japanese quails (1-5 weeks old). RESULTS: Data revealed improvement (p<0.05) of weight gain, feed conversion ratio and European efficiency index due to 1, 2 g (SP)/kg VPD, and 2 g (SP)/kg FMPD, respectively. There was a significant decrease of ileum mean pH value by 1 g (SP)/kg VPD. Concerning gut microbiota, there was a trend toward an increase in Lactobacilli count in both 1; 2 g (SP)/kg VPD and 2 g (SP)/kg FMPD. It was concluded that 1 or 2 g (SP)/kg vegetarian diet may enhance parameters of performance without obvious effect on both meat quality and gut microbiota. Moreover, 1 and/or 2 g (SP) may not be invited to share fish meal based diet for growing Japanese quails. CONCLUSION: Using of SP will support the profitable production of Japanese quails fed vegetable protein diet.

Identification of newly isolated Talaromyces pinophilus and statistical optimization of ß-glucosidase production under solid-state fermentation.

Fungi able to degrade agriculture wastes were isolated from different soil samples, rice straw, and compost; these isolates were screened for their ability to produce ß-glucosidase. The most active fungal isolate was identified as Talaromyces pinophilus strain EMOO 13-3. The Plackett-Burman design is used for identifying the significant variables that influence ß-glucosidase production under solid-state fermentation. Fifteen variables were examined for their significances on the production of ß-glucosidase in 20 experimental runs. Among the variables screened, moisture content, Tween 80, and (NH4)2SO4 had significant effects on ß-glucosidase production with confidence levels above 90% (p < 0.1). The optimal levels of these variables were further optimized using Box-Behnken statical design. As a result, the maximal ß-glucosidase activity is 3648.519 U g(-1), which is achieved at the following fermentation conditions: substrate amount 0.5 (g/250 mL flask), NaNO3 0.5 (%), KH2PO4 0.3 (%), KCl 0.02 (%), MgSO4 · 7H2O 0.01 (%), CaCl2 0.01 (%), yeast extract 0.07 (%), FeSO4 · 7H2O 0.0002 (%), Tween 80 0.02 (%), (NH4)2SO4 0.3 (%), pH 6.5, temperature 25°C, moisture content 1 (mL/g dry substrate), inoculum size 0.5 (mL/g dry substrate), and incubation period 5 days.

Optimization of ß-glucosidase production by Aspergillus terreus strain EMOO 6-4 using response surface methodology under solid-state fermentation.

Forty-two morphologically different fungal strains were isolated from different soil samples and agricultural wastes and screened for ß-glucosidase activity under solid-state fermentation. Eight species were chosen as the most active ß-glucosidase producers and were subjected to primary morphological identification. ß-Glucosidase was highly produced by Aspergillus terreus, which showed the highest activity, and was subjected to full identification using scanning electron microscopy and molecular identification. Initial screening of different variables affecting ß-glucosidase production was performed using Plackett-Burman design and the variables with statistically significant effects were identified. The optimal levels of the most significant variables with positive effect and the effect of their mutual interactions on ß-glucosidase production were determined using Box-Behnken design. Fifteen variables including temperature, pH, incubation time, inoculum size, moisture content, substrate concentration, NaNO3, KH2PO4, MgSO4 · 7H2O, KCl, CaCl2, yeast extract, FeSO4 · 7H2O, Tween 80, and (NH4)2SO4 were screened in 20 experimental runs. Among the 15 variables, NaNO3, KH2PO4 and Tween 80 were found as the most significant factors with positive effect on ß-glucosidase production. The Box-Behnken design was used for further optimization of these selected factors for better ß-glucosidase production. The maximum ß-glucosidase production was 4457.162 U g(-1).

Multifocal periostitis as a complication of chronic use of voriconazole in a lung transplant recipient.

Fungal infections are common in solid organ transplantation. An increasing number of transplant recipients receive antifungal therapy for prolonged duration owing to invasive fungal infections. Herein, we describe a diagnosis of periostitis as a complication of chronic use of voriconazole in a lung transplant recipient. The patient was diagnosed with probable pulmonary aspergillosis and was treated with oral voriconazole for a total of 9 months. Evidence of multifocal periostitis was observed in the axial and appendicular skeleton. Early recognition of this phenomenon is important to prevent unnecessary tests and procedures. Prompt discontinuation of voriconazole should result in improvement of symptoms.

Effect of follicular fluid oxidative stress parameters on intracytoplasmic sperm injection outcome.

OBJECTIVE: The purpose of this study was to evaluate the association between the follicular fluid (FF) reactive oxygen species (ROS) levels, total antioxidant capacity (TAC) and ROS-TAC score and pregnancy after intracytoplasmic sperm injection (ICSI). METHODS: A total of 138 consecutive women who had ICSI were included in this study. FF ROS and TAC were measured by enhanced chemiluminescence and colorimetric assay, respectively, and then the ROS-TAC score was calculated. RESULTS: Out of the 138 included patients, 42 (30%) achieved pregnancy after ICSI. Log ROS, TAC, and the ROS-TAC score were not significantly different across diagnoses. Pregnant cycles were associated with significantly lower ROS (P < 0.001), higher TAC (P < 0.001) and higher ROS-TAC scores (P < 0.001). After adjusting for age, there was a significant positive correlation between log ROS and the number of follicles on the day of HCG administration (correlation 0.20, 95% CI: 0.02, 0.39) as well as the number of oocytes retrieved (correlation 0.18, 0.001, 0.36) but not with TAC. Interestingly, in women with endometriosis, higher TAC levels and higher ROS-TAC scores were associated with a higher likelihood of finding normal oocytes (P = 0.005 and P = 0.002, respectively). CONCLUSION: Higher FF TAC, higher FF ROS-TAC scores and lower FF ROS levels are associated with pregnancy after ICSI. Oxidative stress parameters may be markers of metabolic activity within the follicle.

Enzymatic properties of lipase and characteristics production by Lactobacillus delbrueckii subsp. bulgaricus.

Some properties of an extracellular lipase produced by Lactobacillus delbrueckii subsp. bulgaricus were studied. Maximum enzyme activity was found against olive and butter oil as enzyme substrates. Addition of 9% acacia gum, 0.1% Na-deoxycholate and 0.01 M CaCl2 to the enzyme reaction mixture increased-lipase activity from 5.3 to 14.5 (FFA/mg protein/minute) at pH 6.0 and at 40 degrees C. Maximum lipase production was reached in the presence of glucose as a sole source of carbon, wheat bran as nitrogen source, olive oil as a sole lipid source and butyric acid as fatty acid supporting the growth medium. An initial pH value of the culture medium of 6.0 and a temperature of 35 degrees C gave the highest lipolytic activity.

A periodic structure in the 'pen' chitin of the squid Loligo vulgaris.

The organization of the chitin-proteoglycan in Loligo vulgaris pen was examined ultrastructurally and related to the molecular order indicated by X-ray diffraction. There is a centrosymmetric striated repeat of 22 nm in the system which is based upon dark and light bands of unequal width. The banding is orientated perpendicular to the direction of the major molecular axis of the chitin fibres. The chitin molecules are laid down in sheets with a mutual, though irregular, twist to produce a laminated 'plywood' material.