Acid Function Research Articles

Metal Ion Sensing by Tetraloop-like RNA Fragment: Role of Compact Intermediates with Non-Native Metal Ion-RNA Inner-Shell Contacts.

Divalent metal ions influence the folding and function of ribonucleic acid (RNA) in the cells. The mechanism of how RNA structural elements in riboswitches sense specific metal ions is unclear. RNA interacts with ions through two distinct binding modes: direct interaction between the ion and RNA (inner-shell (IS) coordination) and indirect interaction between the ion and RNA mediated through water molecules (outer-shell (OS) coordination). To understand how RNA senses metal ions such as Mg2+ and Ca2+, we studied the folding of a small RNA segment from the Mg2+ sensing M-Box riboswitch using computer simulations. This RNA segment has the characteristics of a GNRA tetraloop motif and interestingly requires the binding of a single Mg2+ ion. The folding free energy surface of this simple tetraloop system is multidimensional, with a population of multiple intermediates where the tetraloop and cation interact through IS and OS coordination. The partially folded compact tetraloop intermediates form multiple non-native IS contacts with the metal ion. Thermal fluctuations should break these strong non-native IS contacts so that the tetraloop can fold to the native state, resulting in higher folding free energy barriers. Ca2+ undergoes rapid OS to IS transitions and vice versa due to its lower charge density than Mg2+. However, the ability of Ca2+ to stabilize the native tetraloop state is weaker, as it could not hold the loop-closing nucleotides together due to its weaker interactions with the nucleotides. These insights are critical to understanding the specific ion sensing mechanisms in riboswitches, and the predictions are amenable for verification by nuclear magnetic resonance (NMR) experiments.

Photocatalytic degradation of organic dyes under sunlight using a mononuclear Zn complex-embedded-functionalized porous material.

In this study, mesoporous materials (MCM-41 and MCM-48) were synthesized and functionalized with an acid group through a post-synthetic modification method. A mononuclear Zn complex [Zn(dmp)Cl2] (dmp = neocuprine) was also prepared and incorporated into a functionalized mesoporous material. Extensive characterization of the material married was carried out using techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the characteristics of modified materials. The characterization results revealed that the post-synthetic modification did not alter the phase purity, crystallinity, or morphology of the mesoporous materials while confirming the successful grafting of the desired sulphonic acid functionality and Zn complex. The Zn complex-grafted-functionalized mesoporous materials were then assessed for their photo-degradation using methylene blue (MB) and rhodamine B (RB). The results demonstrated exceptional photo-degradation efficiency of the modified materials under sunlight. Within 15min, 10mg/ml of dye concentration, and adsorbent dosage 0.15mg/ml and 0.1mg/ml, degradation efficiencies of 99% and 92%, were achieved for MB using M-48-S-Zn1 and M-41-S-Zn1, respectively. Similarly, 91% and 78% degradation rates were achieved within 30min for RB using the same materials. The modified mesoporous materials exhibited a remarkable degradation performance even in challenging environments, including highly acidic, basic, and salt-concentrated conditions. This highlights the versatility and robustness of the modified materials in different environmental scenarios.

Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions.

Adsorption of l-Cysteine and Cysteamine on Zinc Oxide Nanoparticles.

The reaction of l-cysteine and cysteamine hydrochloride with zinc oxide nanoparticles (ZnO NPs), by stirring excess reactant with the NPs in ethanol, has been studied by thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. l-Cysteine adsorption occurs via the thiol functional group, and there is no evidence for bonding via the carboxylic acid or amine functionalities. However, Raman spectroscopy and XPS reveal some protonated thiol, suggesting unbound l-cysteine is also present, as confirmed by XRD that shows the presence of l-cysteine crystallites. In the case of cysteamine/ZnO, TGA indicates that a large fraction of the sample is organic, and Raman spectroscopy reveals a dramatic shift in the C-S stretch from 796 cm-1 for unreacted cysteamine to 837 cm-1 for the reacted cysteamine. It is postulated that the acidic and chelating nature of the reaction causes dissolution of some Zn2+ ions that form a Zn(II) coordination complex with cysteamine. These studies have implications for biomolecular applications in which ZnO nanoparticles are used for biosensors, bioimaging, and drug delivery.

The host tropism of current zoonotic H7N9 viruses depends mainly on an acid-labile hemagglutinin with a single amino acid mutation in the stalk region.

The incidence of human infection by zoonotic avian influenza viruses, especially H5N1 and H7N9 viruses, has increased. Current zoonotic H7N9 avian influenza viruses (identified since 2013) emerged during reassortment of viruses belonging to different subtypes. Despite analyses of their genetic background, we do not know why current H7N9 viruses are zoonotic. Therefore, there is a need to identify the factor(s) responsible for the extended host tropism that enables these viruses to infect humans as well as birds. To identify H7N9-specific amino acids that confer zoonotic properties on H7N9 viruses, we performed multiple alignment of the hemagglutinin (HA) amino acid sequences of A/Shanghai/1/2013 (H7N9) and A/duck/Zhejiang/12/2011(H7N3) (a putative, non- or less zoonotic HA donor to the zoonotic H7N9 virus). We also analyze the function of an H7N9 HA-specific amino acid with respect to HA acid stability, and evaluated the effect of acid stability on viral infectivity and virulence in a mouse model. HA2-116D, preserved in current zoonotic H7N9 viruses, was crucial for loss of HA acid stability. The acid-labile HA protein in H7 viruses played an important role in infection of human airway epithelial cells; HA2-116D contributed to infection and replication of H7 viruses. Finally, HA2-116D served as a H7 virulence factor in mice. These results suggest that acid-labile HA harboring HA2-116D confers zoonotic characteristics on H7N9 virus and that future novel zoonotic avian viruses could emerge from non-zoonotic H7 viruses via acquisition of mutations that remove HA acid stability.

Improvement of tetracycline removal using amino acid ionic liquid modified magnetic biochar based on theoretical design

In current research, biochar is widely used to remove antibiotic contamination from the environment. However, original biochar produced through direct pyrolysis has significant limitations in removing antibiotics. In this paper, response surface methodology provided the laudable choice for magnetic poplar biochar (MPBC) considering the synergistic effect of multi-factors as well as the restrictions abundance experiments during the preparation of MPBC. Amino acid ionic liquids (AAILs) are a class of ionic liquids in which amino acids act as the anionic component, combining the tunable properties of ionic liquids with the biocompatibility and functionality of amino acids. To ameliorate adsorption capacity of MPBC, tetra-ethylammonium glycinate ([TEA][Gly]) with the best affinity for tetracycline (TC) were screened from 600 AAILs based on theoretical predictions using the conductor-like screening model for real solvents (COSMO-RS) without extensive experimental. Furthermore, AAILs-modified magnetic biochar (MPBC-AAIL) was synthesized chemically for the first time. Adsorption kinetics, isotherms, and thermodynamic analyses revealed that TC adsorption by both MPBC and MPBC-AAIL is a monolayer, spontaneous, and exothermic chemical process. Moreover, MPBC-AAIL exhibited a maximum adsorption capacity of 305.9 mg·g−1. Meanwhile, MPBC-AAIL maintains superior adsorption performance for TC in different impurity solutions as well as in real water samples. The excellent reusability and selective adsorption capacity of the material demonstrate the superiority of the theoretical based design. The characterization reveals that the adsorption mechanisms include pore filling, π-π interactions, surface complexation, hydrogen bonding, and electrostatic interactions. In addition, theoretical calculations showed that ionic liquid modification altered the adsorption sites between TC and MPBC-AAIL, leading to enhanced adsorption. This comprehensive study introduces an innovative modification of biochar, providing a novel approach to designing biochar composites and promoting their application in the remediation of complex environmental pollution.

Catalytic behavior, electronic structure and spectroscopic (FT-IR, Raman, UV–vis) properties for the new ionic liquid imidazolium hydrogen sulfate

Catalytic performance, chemical reactivity, vibrational modes and electronic transitions of the ion pair [H–Im]+[HSO4]– were investigated in the current paper. Hence, a combined experimental (Hammett acidity function, infrared, Raman and ultraviolet-visible spectroscopies) and theoretical (molecular electrostatic potential surface, reduced density gradient, frontier molecular orbital analysis, quantum theory of atoms in molecules, net atomic charges, global and local reactivity descriptors) study was conducted. In terms of the catalytic performance, the acetic acid esterification with butanol was evaluated. Important kinetic (rate constant, activation energy, pre-exponential factor) and thermodynamic (enthalpy, entropy, Gibbs free energy barrier) factors for ester production as a function of the temperature and catalyst loading have been determined. Results revealed intensive electron density distribution in [H–Im]+[HSO4]– due to chemical interactions between the cationic and anionic moieties. These bonds were established as electrostatic in nature. The pronounced charge transfers within [H–Im]+[HSO4]– managed the title compound acidity (H0) and its catalytic behavior towards butyl acetate synthesis. Using the thermodynamic and kinetic measurements, a mechanism for acetic acid esterification with butanol in the presence of imidazolium hydrogen sulfate ionic liquid was offered.

Discovery and Biosynthesis of Sulfenicin and Its New-to-Nature Acylsulfenic Acid Functional Group.

Life's organic molecules are built with diverse functional groups that enable biology by fine tuning intimate connections through time and space. As such, the discovery of new-to-nature functional groups can expand our understanding of the natural world and motivate new applications in biotechnology and biomedicine. Herein we report the genome-aided discovery of sulfenicin, a novel polyketide-nonribosomal peptide hybrid natural product from a marine Streptomyces bacterium bearing a unique acylsulfenic acid functionality. Through a series of heterologous biosynthesis, functional genetics, and enzymatic reconstitution experiments, we show that this previously described synthetic functional group is biologically assembled by a set of enzymes from both primary and secondary metabolism, including a novel flavin-dependent S -hydroxylase that hydroxylates a thiocarboxylic acid's sulfur atom. While the sulfenicin biosynthetic gene cluster is presently without parallel in public databases, acylsulfenic acid-encoding enzymes are widely distributed in bacterial genomes, implying that this labile functional group may similarly have a broad distribution among specialized metabolites.

α-Mangostin Attenuates Blood Pressure and Reverses Vascular Remodeling by Balancing ACE/AT1R and ACE2/Ang-(1-7)/MasR Axes in Ang II-Infused Hypertensive Mice.

Hyperuricemia is a common comorbidity of hypertension and probably has a causal relationship with hypertension. Alpha-mangostin (α-MG) has been reported to have uric acid lowering effect. This study aimed to investigate the dual effects of α-MG on blood pressure (BP) and uric acid levels in angiotensin II (Ang II)-infused hypertensive mice. Male C57BL/6 mice were randomized into five groups: control, Ang II infusion (500 ng/kg/min for 2 weeks), Ang II infusion with gavage administration of α-MG 4.0 and 8.0 mg/kg and benzbromarone (25 mg/kg) respectively. BP, uric acid levels, vascular structure and function, and renin-Ang II system expressions in the aorta were assessed. Treatment with α-MG reduced BP, improved endothelial relaxation, and reversed aortic wall thickening and collagen deposition in Ang II-induced hypertensive mice. It also downregulated Ang II receptor 1 (AT1R) and angiotensin converting enzyme (ACE) expression, while upregulating ACE2, Mas receptor (MasR), and angiotensin (1-7) in the aorta. Moreover, α-MG demonstrated a significant enhancement in uric acid clearance and reduction in serum uric acid levels. Conversely, benzbromarone did not result in a decrease in BP, indicating that the hypotensive effect of α-MG may not be necessarily dependent on its urate-lowering properties. α-MG can attenuate Ang II-induced hypertension and reverse vascular remodeling, potentially by balancing the ACE/Ang II/AT1R axis and the ACE2/Ang-(1-7)/MasR axis. Our findings provide insights into α-MG as a novel anti-hypertensive drug especially in patients with hyperuricemia.

Interaction of CTCF and CTCFL in genome regulation through chromatin architecture during the spermatogenesis and carcinogenesis.

The zinc finger protein CTCF is ubiquitously expressed and is integral to the regulation of chromatin architecture through its interaction with cohesin. Conversely, CTCFL expression is predominantly restricted to the adult male testis but is aberrantly expressed in certain cancers. Despite their distinct expression patterns, the cooperative and competitive mechanisms by which CTCF and CTCFL regulate target gene expression in spermatocytes and cancer cells remain inadequately understood. In this review, we comprehensively examine the literature on the divergent amino acid sequences, target sites, expression profiles and functions of CTCF and CTCFL in normal tissues and cancers. We further elucidate the mechanisms by which CTCFL competitively or cooperatively binds to CTCF target sites during spermatogenesis and carcinogenesis to modulate chromatin architecture. We mainly focus on the role of CTCFL in testicular and cancer development, highlighting its interaction with CTCF at CTCF binding sites to regulate target genes. In the testis, CTCF and CTCFL cooperate to regulate the expression of testis-specific genes, essential for proper germ cell progression. In cancers, CTCFL overexpression competes with CTCF for DNA binding, leading to aberrant gene expression, a more relaxed chromatin state, and altered chromatin loops. By uncovering the roles of CTCF and CTCFL in spermatogenesis and carcinogenesis, we can better understand the implications of aberrant CTCFL expression in altering chromatin loops and its contribution to disease pathogenesis.

Manganese nanoparticles catalyzed the formation of mesoporous helical nitrogen-doped carbon nanotubes enabled aldosterone biosensing

Primary aldosteronism (PA) is the foremost form of secondary hypertension that affects 5–20 % of healthy humans via the excessive secretion of aldosterone (ALD), which increases the level of potassium excretion and thus produces various critical combined diseases. Thus, determining trace-level ALD content in human blood or urine samples is a crucial factor in diagnosing a life-threatening disease called PA. Herein, nanosized manganese particles encapsulated within the tunable helical-shaped N-doped mesoporous carbon nanotubes (Mnx@H-NCNTs) are synthesized by a simple and facile ball-milling method at different reaction times (1, 6, 12, and 18 h). The influence of ball-milling process time on the final morphology of the as-synthesized Mnx@H-NCNTs nanostructures is systematically investigated. In order to fabricate an ALD biosensor electrode, the immobilization of Anti-ALD antibodies (Anti-ALD) on the surface of the Mn@H-NCNTs-12H electrode (Anti-ALD/Mn@H-NCNTs-12H) is achieved via the interactions of combined interactions of hydrogen bonds, Van der Waals’ force, negatively charged carboxylic acid functionalities of antibodies and positively charged metal centers, and π-π stacking interaction between nucleosides of Anti-ALD and mesoporous H-NCNTs. In addition, BSA was used as a blocking additive for covering non-specific adsorption sites of Anti-ALD/Mnx@H-NCNTs (BSA/Anti-ALD/Mn@H-NCNTs-12H) nanostructured electrodes. The BSA/Anti-ALD/Mn@H-NCNTs-12H can be used as an effective signal amplifying probe for ALD detection through a noticeable reduction in the amperometric i-t current response over a linear range from 1 to 2500 pM, with a LOD of 0.72 pM (S/N = 3). The practical applicability of BSA/Anti-ALD/Mn@H-NCNTs-12H is further demonstrated by the detection of ALD from 1 to 20 nM in human blood or urine samples with a recovery ranging from 90.5 to 97.0 %, indicating its potential use in clinical analysis.

Synthesis of (-)-Monanchoradin A and (-)-Crambescin A2 392 Based on a Cyclization-Carbonylation-Cyclization Cascade.

Syntheses of guanidino alkaloids (-)-monanchoradin A and (-)-crambescin A2 392 are described. The key feature of the syntheses is the cyclization-carbonylation-cyclization cascade of the optically active propargyl guanidine. The bicyclic guanidino cores bearing an asymmetric center and ester or carboxylic acid functionality were constructed in a single step. The carboxylic acid was then converted to (-)-monanchoradin A and (-)-crambescin A2 392.

Thermodynamics and Kinetic Study for Removal of Orange-G Dye from Aqueous Solution by Nano Composite

In this study, where graphene oxide was prepared by Hummer method, while copper oxide was prepared in the green way using (capparies spinosa) plant extract as a reducing agent, these oxides were diagnosed as well as the binary nanocomposite by several techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-rays diffraction , and field Emission scanning electron microscopy (FESEM), after that the superimposed (GO/CuO) was used to adsorbent the orange G dye ( Orange - G) from its aqueous solutions, A number of factors affecting adsorption were studied (equilibrium time, surface weight, pH, concentration effect, temperature). The results showed that the ideal time for adsorption of the orange dye (orange-G) on the surface of the nanocomposite (GO/CuO) was (30min), the best ideal weight for dye removal was (0.05gm), the best concentration was (20ppm), and the best acid function was (pH=2). After that, the adsorption kinetics were also studied by applying the pseudo first and second order of adsorption. The results showed that the adsorption process follows the false second-order kinetics. The thermodynamic functions of the removal process were also studied, and it was found that the value of (DH) is negative for the surface of the composite (GO/CuO) with dye. Meaning the adsorption process is exothermic, and that the DG0 has negative value, meaning that the adsorption processes occur spontaneously. positive DS0 values indicate that the molecules are becoming less bound

Tailoring Fumaric Acid Delivery: The Role of Surfactant-Enhanced Solid Lipid Microparticles via Spray-Congealing.

Fumaric acid, a naturally occurring preservative with antimicrobial properties, has been widely used in the baking industry. However, its direct addition interferes with yeast activity and negatively impacts the gluten structure. This study investigates the potential of spray-congealing as a method for encapsulating fumaric acid within solid lipid microparticles. The selection of lipid carriers and surfactants is critical, so hydrogenated palm stearin, hydrogenated rapeseed oil, and Compritol ATO 888 (glyceryl behenate) were chosen as lipid carriers, and propylene glycol monostearate and glyceryl monolaurate were utilised as surfactants with varying concentrations. Rheological properties, encapsulation efficiency, particle size, moisture content, and thermal behaviour were assessed, along with the release profiles under different temperature conditions simulating the baking process. The findings indicate that the addition of surfactants significantly impacts the viscosity and stability of the molten mixtures, which in turn affects the spray-congealing process and the release of fumaric acid. The temperature-dependent and time-dependent release profiles demonstrate the potential for customising release kinetics to suit specific applications, such as the baking industry. This study may contribute to the development of a controlled-release system that synchronises with the baking process, thereby optimising fumaric acid's functionality while preserving the quality of baked goods.

Chlorogenic Acid Plays an Important Role in Improving the Growth and Antioxidant Status and Weakening the Inflammatory Response of Largemouth Bass (Micropterus salmoides).

This experiment evaluated the function of chlorogenic acid (CGA) in the growth, health status, and inflammation of largemouth bass (Micropterus salmoides). Over eight weeks, CGA supplementation was designed at five levels: 0, 60, 120, 180, and 240 mg/kg. The 180 and 240 mg/kg CGA-supplemented groups showed significant improvements in the FBW, SGR, and WGR compared to the control group (0 mg/kg) (p < 0.05). All the CGA-supplemented groups exhibited a significant reduction in the FCR (p < 0.05), with the 180 mg/kg CGA group showing the lowest FCR. Nonetheless, there were no appreciable differences in the plasma concentrations of TP, ALT, or AST among the treatments (p > 0.05). Compared to the control group, the 180 mg/kg CGA group exhibited significantly lower TC and TG levels (p < 0.05). The ALP levels showed no significant differences from the control group (p > 0.05). In terms of antioxidant parameters, CGA supplementation considerably reduced the MDA content (p < 0.05) and increased the GSH levels, while decreasing the CAT, SOD, and GPx activity levels Meanwhile, CGA supplementation resulted in reduced mRNA levels of SOD, CAT, Nrf2, Keap1, and NF-κB compared to the control group. In contrast, the mRNA levels of GPx, IL-8, TLR2, and RelA were elevated in the liver. Our findings indicated that CGA supplementation improved the growth performance and antioxidant status and weakened the inflammatory response of largemouth bass. These findings suggest that CGA could be a valuable dietary supplement for enhancing the health and growth of this species.

Osteogenic citric acid linked chitosan coating of 3D-printed PLA scaffolds for preventing implant-associated infections

>25 % of the patients who receive orthopedic implants have been reported with implant-associated osteomyelitis, which can result in inflammation, osteolysis, and aseptic loosening of implants. Current treatment methods doesn't ensure defect healing and prevention from reinfection. Thermoplastic-based 3D-printed scaffolds offer a bioresorbable, biocompatible, and mechanical strong implant system. However, the hydrophobicity and bio-inertness of these polymers prevent their use in clinics. In this study, we developed dual functionalized scaffolds with osteogenic and antibacterial properties by immobilizing citric acid-linked chitosan on oxygen plasma etched 3D-printed PLA scaffolds through an EDC-NHS coupling reaction. Acellular mineralization of these scaffolds in DMEM demonstrated the deposition of crystalline hydroxyapatite. In addition, the antibacterial properties of these surface-modified scaffolds have been determined against E. coli and S. aureus, where the citric-linked chitosan biofunctionalized 3D-printed PLA scaffolds showed significantly higher antibacterial activity in comparison to oxygen-etched PLA and PLA scaffolds due to the synergistic effect of citric acid and chitosan functionalities. MG-63 cells exhibited increased proliferation and osteogenic activity on the modified scaffolds compared to the PLA and OP-PLA. These 3D-printed scaffolds, coated with citric-linked chitosan, can be a potential solution to orthopedic complications such as critical-sized bone defects and implant-associated osteomyelitis.

Association between uric acid and cognitive function in maintenance hemodialysis patient

Background: Chronic kidney disease (CKD) is an independent risk factor for cognitive dysfunction. Hyperuricemia is prevalent in CKD patients and has been associated with cognitive dysfunction. Hyperuricemia has been associated with an increased risk for cerebral microvascular disease. Aims and Objectives: The study aimed to evaluate the association between uric acid level and cognitive function in maintenance hemodialysis patients. Materials and Methods: The study was conducted on 90 maintenance hemodialysis patients. Serum uric acid (sUA) level was measured in patients on maintenance hemodialysis and cognitive performance was assessed by the Standardized Mini-Mental State Examination score. Results: There was a significant association between sUA level and cognitive function in hemodialysis patients. Patient with higher sUA levels was found to have poor cognitive function (P&lt;0.05). There was a significant negative correlation between sUA and cognitive function which revealed an increase in sUA will decrease the cognitive function (P&lt;0.05). In our study, there was a significant association between sUA and cognitive function in hemodialysis patients. Patients with hyperuricemia had poor cognitive function. Conclusion: In our study, there was a significant association between sUA and cognitive function in hemodialysis patients. Patients with hyperuricemia had poor cognitive function.

Insights into the adsorption mechanism of chlorpyrifos on activated carbon derived from prickly pear seeds waste: An experimental and DFT modeling study

The removal of chlorpyrifos (CPF) from water was achieved using activated carbon (AC) derived from prickly pear seeds (PPS) wastes, developed through chemical activation with phosphoric acid. Several physico-chemical characterization methods were employed. The determination of surface functions using the Boehm assay indicated that the processed AC predominantly possesses acidic functions. The results obtained from the Boehm assay were corroborated by the pH value of the point of zero charge (pHpzc), which was equal to 2.5. Specific area calculation by the BET (Brunauer Emmett Teller) method revealed a large specific area (SBET) of 1077.66 m2 g⁻1. Adsorption experiments of CPF on AC demonstrated that the pseudo-second order (PSO) model and the Freundlich model were the most suitable for kinetic and isothermal modeling, respectively. The maximum CPF adsorption capacity of the PPS AC was found to be approximately 35 mg g⁻1. A theoretical study employing the density functional theory (DFT) was conducted using the B3LYP/6-311G (d, p) method. The most reliable adsorption energy (Eads) and Gibbs free energy (ΔGads) values between CPF and the functional groups on the AC surface were calculated. Results indicated a strong interaction between the lactone group of AC and CPF (ΔGads = −7.15 kcal mol⁻1, ΔEads = −21.55 kcal mol⁻1) and the hydroxyl group (ΔGads = −6.61 kcal mol⁻1, ΔEads = −20.66 kcal mol⁻1). This study demonstrates that activated carbon possesses significant adsorption power, making it highly effective for depolluting water contaminated by pesticides. The application of the theoretical DFT method enhances the understanding of the adsorption phenomenon of CPF on AC.

Heteropolyacid and Lithium Infused Calcium Oxide Catalyst for Biodiesel Production from Food Waste

The advancement of mixed metal oxide catalysts has attracted considerable attention among various workers. Supported MoOx catalyst materials possess more Lewis and Brønsted acid functionalities which assist in the efficient biodiesel production. In this study, ammonium molybdate and Li+ were loaded over eggshells-derived calcium oxide to transesterify the frying oil/waste cooking oil (WCO) to produce biodiesel/fatty acid methyl ester (FAME). Characterization techniques i.e., X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were employed to confirm the material. The surface modelling predicted the transesterification reaction parameters. The optimal condition to transesterify WCO with synthesized Mo/Li/CaO catalyst was 6 wt.% catalyst dose, 13.70:1 ratio of methanol:oil (m/o), time of 1 h and 60 ºC temperature. The optimum FAME yield of 97% was observed. The gas chromatography-mass spectroscopy (GC-MS) and other spectroscopic techniques were used to analyze produced FAME. The reusability of catalyst was good and the catalyst can be reutilized effectively up to a limit of 5 runs. By leveraging this innovative catalyst derived from eggshells, this study contribute to a more sustainable and cost-effective biodiesel production process.

Biological function of sialic acid and sialylation in human health and disease.

Sialic acids are predominantly found at the terminal ends of glycoproteins and glycolipids and play key roles in cellular communication and function. The process of sialylation, a form of post-translational modification, involves the covalent attachment of sialic acid to the terminal residues of oligosaccharides and glycoproteins. This modification not only provides a layer of electrostatic repulsion to cells but also serves as a receptor for various biological signaling pathways. Sialylation is involved in several pathophysiological processes. Given its multifaceted involvement in cellular functions, sialylation presents a promising avenue for therapeutic intervention. Current studies are exploring agents that target sialic acid residues on sialoglycans or the sialylation process. These efforts are particularly focused on the fields of cancer therapy, stroke treatment, antiviral strategies, and therapies for central nervous system disorders. In this review, we aimed to summarize the biological functions of sialic acid and the process of sialylation, explore their roles in various pathophysiological contexts, and discuss their potential applications in the development of novel therapeutics.