Kinetic Model Research Articles

Equilibrium adsorption, kinetic, thermodynamic, and breakthrough curves modelling of acetaminophen on Elaeagnus Angustifolia L. seeds-based granular activated carbon

ABSTRACT The widespread presence of pharmaceutical compounds as emerging environmental contaminants in aquatic environments has become a significant concern in recent years. In this study, synthesised granular activated carbon (GAC) derived from Elaeagnus Angustifolia L. seeds was utilised as an adsorbent to remove an emerging contaminant, acetaminophen (commercially known as paracetamol). The operating conditions for the chemical synthesis of the GAC, utilising ZnCl2 as an activating agent, included an impregnation ratio of 1:1, carbonisation at 500°C for 1 hour, and a heating rate of 5 °C/min. The efficacy of this adsorbent was assessed through both batch and fixed-bed column adsorption experiments under various operational parameters, including adsorbent mass (1–6 g/L), contact time, pH (2–10), temperature (20–60°C), inlet acetaminophen concentration (20–150 mg/L), and flow rate (0.5–1.5 mL/min). The results indicate that acetaminophen was better adsorbed in its neutral form rather than in its dissociated state. The findings also revealed that both the Langmuir (two-parameter) and Sips (three-parameter) models provided the best fit for the static adsorption equilibrium data. Furthermore, kinetic analysis indicated that the experimental data were best modelled by the Elovich model and governed by both external diffusion and intraparticle diffusion mechanisms. Therefore, the Yan-Viraraghavan model provided a good fit for the experimental breakthrough curves under various operating conditions. However, the adsorbed amounts of acetaminophen obtained from the column experiment indicated that the high-adsorbed amount of 204.11 mg/g was achieved with an inlet acetaminophen concentration of 150 mg/L, a bed depth of 6 cm, and a flow rate of 0.5 mL/min. These results highlight the potential of the synthesised GAC as a promising adsorbent for pharmaceutical wastewater treatment using fixed-bed column systems.

Adsorptive flotation of cesium radionuclides from aqueous solutions using rice straw agriculture waste as a low-cost and eco-friendly adsorbent

ABSTRACT The removal of caesium radionuclides from an aqueous solution by flotation using rice straw (RS) agricultural waste as a low-cost and eco-friendly adsorbent in the presence of potassium ferrocyanide (KFC) was investigated. The influence of many adsorption parameters and flotation was evaluated on the removal efficiency of 137Cs. The adsorption results demonstrated that the concerned radionuclide was efficiently removed in the presence of 2 × 10−4 mol/L KFC using 10 g/L RS at pH ≥ 7. The double exponential kinetic model and the Freundlich model were the best models for fitting the adsorption kinetic and isotherm data, respectively. The maximum adsorption capacity of RS, calculated from the Langmuir model, was 280.405 mg/g. after being transferred to the flotation cell, 137Cs loaded onto ferrocyanide-modified rice straw (FMRS) was successfully floated at pH 7 using 3 × 10−4 mol/L cetyltrimethylammonium bromide (CTAB) surfactant in the presence of 4% ethanol. Removal percentages of 56% and > 99.5% were achieved for 137Cs-loaded FMRS within 5 min using sodium dodecyl sulphate (SDS) and CTAB, respectively. The results obtained in this investigation indicate the efficiency of the suggested strategy and hence its applicability for the removal of 137Cs+ from radioactive liquid wastes.

Ultrasonic high-yield extraction of non-toxic fucose-containing Abroma augusta polysaccharide bearing emulsifying properties.

The stem of Abroma augusta contains mucilaginous polysaccharides having numerous ethnomedicinal properties. The present work aimed to develop a scalable ultrasonic-assisted aqueous Abroma augusta mucilage (AAM) extraction (UAE) method and further explores its emulsifying property and toxicity concern. The combination of ultrasonic power (750 W), solid-to-liquid ratio (1:15) and temperature (348 K) gave the highest extraction yield of 2.28% with a diffusivity value of 3.85 × 10-9 m2 s-1, which was higher than aqueous extraction method using a kinetic model based on Fick's second law of diffusion. The extracted polysaccharide showed no toxicity as measured through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay on RAW cell line. Additionally, the polysaccharide over its critical micelle concentration (400, 500, 600 and 700 μg mL-1) offered emulsifying properties with 0.5%, 1% and 5% oil (v/v). The emulsion with a polysaccharide concentration of 600 μg mL-1 with 5% oil (v/v) provides stability against coalescence for 3 days. The overall findings indicated that UAE of AAM polysaccharide can be used for an efficient extraction method, and the obtained polysaccharide is nontoxic in nature and bears emulsifying properties. © 2024 Society of Chemical Industry.

Study on the optimal conductivity titration parameters for SO42- in cement-based materials

Accurately obtaining the SO42- content in concrete is a prerequisite for revealing mechanism of sulfate attack, establishing model of sulfate attack, proposing durability design methods. The feasibility of testing SO42- in cement-based materials by conductivity titration was investigated by the author in previous research. Therefore, this study further investigated the optimal conductivity titration parameters and standard for determining the endpoint of titration curve by establishing a conductivity titration kinetic model (CTKM). Based on the proposed CTKM, optimal range of titration parameters such as the volume of measured solution, solution concentration standard titrant and titration rate were obtained, and the effects of other ions on optimal range of titration parameters were also discussed. The results show that among the six stages on the titration curve of SO42- (undersaturation stage, crystal nucleation stage, crystal growth stage, quasi reaction end stage, reaction end stage and infinite titration stage), crystal growth stage and reaction end stage are essential. The titration curves calculated by the CTKM are in good agreement with the measured curves. The included angle between the left and right tangents of a point on the normalized conductivity titration curve can be a good criterion for determining the titration end point. When the included angle exceeds 10°, the titration end point is easily determined. The optimal range of titration parameters are confined by the minimum measured solution volume to submerge the conductivity electrode (about 5 mL), the maximum measured solution volume to be stirred evenly (about 10 mL), and the appropriate added volume of standard titrant to ensure titration accuracy (between 1 and 1.5 mL), and the included angle to be easily determined (greater than 10°). The influence of H+, OH–, Cl-, and Na+ on SO42- titration gradually weakens. In composite solution containing 0.01 mol/L SO42-, when the concentration of H+ exceeds 0.1 mol/L, or the concentration of OH– exceeds 0.2 mol/L, directly titrating SO42- is difficult and a deionization process is required.

Nanopore tweezers show fractional-nucleotide translocation in sequence-dependent pausing by RNA polymerase

RNA polymerases (RNAPs) carry out the first step in the central dogma of molecular biology by transcribing DNA into RNA. Despite their importance, much about how RNAPs work remains unclear, in part because the small (3.4 Angstrom) and fast (~40 ms/nt) steps during transcription were difficult to resolve. Here, we used high-resolution nanopore tweezers to observe the motion of single Escherichia coli RNAP molecules as it transcribes DNA ~1,000 times improved temporal resolution, resolving single-nucleotide and fractional-nucleotide steps of individual RNAPs at saturating nucleoside triphosphate concentrations. We analyzed RNAP during processive transcription elongation and sequence-dependent pausing at the yrbL elemental pause sequence. Each time RNAP encounters the yrbL elemental pause sequence, it rapidly interconverts between five translocational states, residing predominantly in a half-translocated state. The kinetics and force-dependence of this half-translocated state indicate it is a functional intermediate between pre- and post-translocated states. Using structural and kinetics data, we show that, in the half-translocated and post-translocated states, sequence-specific protein-DNA interaction occurs between RNAP and a guanine base at the downstream end of the transcription bubble (core recognition element). Kinetic data show that this interaction stabilizes the half-translocated and post-translocated states relative to the pre-translocated state. We develop a kinetic model for RNAP at the yrbL pause and discuss this in the context of key structural features.

Artificial neural networks (ANN)-genetic algorithm (GA) optimization on thermosonicated achocha juice: kinetic and thermodynamic perspectives of retained phytocompounds

The extraction of phytocompounds from Achocha (Cyclanthera pedata) vegetable juice using traditional methods often results in suboptimal yields and efficiency. This study aimed to enhance the extraction process through the application of thermosonication (TS). To achieve this, an artificial neural network (ANN) and a genetic algorithm (GA) were utilized to simulate and optimize the process parameters. The study investigated the influence of ultrasonic amplitude (30%–50%), temperature (30 °C–50 °C), and sonication duration (15–60 min) on total polyphenolic content (TPC), total flavonoid content (TFC), antioxidant activity (AOA), and ascorbic acid content (AA). Remarkably, the ANN-GA optimization resulted in optimal TS conditions: an ultrasonic amplitude of 40%, a temperature of 40 °C, and a sonication duration of 30 min. Subsequent analysis of extraction kinetics and thermodynamics across various temperatures (30 °C–50 °C) and extraction times (0–30 min) demonstrated R 2 (0.98821) and χ2 (1.74773) for TPC with activation energy (Ea) 26.0456, R 2 (0.99906) and χ2 (0.07215) for TFC with Ea 26.2336, R 2 (0.99867) and χ2 (0.03003) for AOA with Ea 26.0987, R 2 (0.99731) and χ2 (0.13719) for AA with Ea 26.0984, validating the pseudo second-order kinetic model. These findings indicate that increased temperature enhances the saturation concentration and rate constant of phytochemical extraction.

Significant enhancement on ammonia removal by thermal/peroxymonosulfate system with bromide ion: Performance, influencing factors and mechanism

Although thermal-activated peroxymonosulfate (PMS) system possesses good performance on the removal of organic pollutants, thermal/PMS system exhibited poor capacity to remove ammonia nitrogen (NH4+-N). This study demonstrated the huge enhancement on the removal of NH4+-N by thermal/PMS system with the commonly coexistent bromide ion (Br-). The elimination of NH4+-N by thermal/PMS/Br- system fitted the pseudo-zero-order kinetics model well, while the corresponding kobs in the presence of 200 μM Br- was 5.76 times greater than that by thermal/PMS system. Bromine (HBrO) was confirmed as the dominant oxidant responsible for removing NH4+-N and TN, while the radicals of HO⋅, SO4⋅- and Br⋅ were also generated but made minor contribution to removing NH4+-N. HBrO was mostly produced by PMS reacting directly with Br-, while these radicals were produced from the cleavage of the O-O bond in PMS and the reaction between PMS and HBrO under high temperature. Thermal/PMS/Br- system exhibited superior performance on TN removal (up to 90 %) than that by thermal/PMS system (less than 5 %) and Cl--enhanced system (about 80 %). The main removal product of NH4+-N was identified as the environmentally friendly gas of N2, although nitrate was also detected. Neutral pH condition was the optical pH for NH4+-N removal. Increasing reaction temperature, PMS dosage and Br- concentration were beneficial to accelerating the removal of NH4+-N. Cations of Cu2+ and Fe3+, anions of SO42-, CO32- and NO3-, humic acid and the actual water matrix of landfill leachate negligibly influenced the removal of NH4+-N, while Cl- exhibited strong enhancement on NH4+-N removal. In summary, this study provided an effective method to improve the oxidizing capacity of thermal/PMS system, especially for NH4+-N removal in wastewater containing Br-.

Effective degradation of azo dyes by ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) mediated laccase. Kinetic studies

Laccases are enzymes with low substrate specificity that in certain cases require the presence of a mediator in order to work properly. Therefore, this paper investigated the degradation of Orange G, Ponceau 4 R and Methyl Red in the presence of laccase isolated from Trametes versicolor and laccase-ABTS system. Laccase, in high concentration, was able to oxidize only Orange G and Ponceau 4 R, with a degree of decolorization less than 10 % in 20 min. In the presence of laccase-ABTS system, the reaction is much faster, and at least 40 % of dyes were degraded in 15 min. A kinetic model accounting for enzymatic oxidation of all dyes, including a step for enzyme operational inactivation, was proposed. This study proves that we can use a single kinetic model for the oxidation of all dyes in the laccase-ABTS system.

Investigation of the Potential of Repurposing Medium-Density Fiberboard Waste as an Adsorbent for Heavy Metal Ion Removal.

Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions. The experimental data of Pb(II) ions fit well with the Freundlich isotherm and pseudo-second-order kinetic models. Complexation and electrostatic interactions were identified as the adsorption mechanisms. The adsorption behavior of multi-metal ion adsorption systems was investigated by introducing Cd(II) ions as a competitive metal ion. The presence of the Cd(II) ions reduced the adsorption potential of Pb(II) ions, yet the preference for the Pb(II) ions remained. Regeneration studies were performed by using 0.1 M HCl as a regeneration agent for both systems. Even though a significant amount of adsorbed metal ions were recovered, the adsorption potential of the MDF was reduced in the subsequent adsorption cycles. Based on these results, MDF fines have the potential to be used as an economical adsorbent for remediation of wastewater containing heavy metal ions.

Formulation of silver phosphate/graphene/silica nanocomposite for enhancing the photocatalytic degradation of trypan blue dye in aqueous solution

Photocatalytic degradation of several harmful organic compounds has been presented as a potential approach to detoxify water in recent decades. Trypan Blue (TB) is an acidic azo dye used to distinguish live cells from dead ones and it's classified as a carcinogenic dye. In this study, silver phosphate (Ag3PO4) nanoparticles and novel Ag3PO4/graphene/SiO2 nanocomposite have been successfully prepared via simple precipitation method. Afterward, their physical properties, chemical composition, and morphology have been characterized using SEM, EDS, TEM, SAED, BET, XRD, FTIR and UV–VIS spectroscopy. The specific surface area of Ag3PO4 and Ag3PO4/G/SiO2 nanocomposite were reported to be 1.53 and 84.97 m2/g, respectively. The band gap energy of Ag3PO4 and Ag3PO4/G/SiO2 nanocomposite was measured to be 2.4 and 2.307 eV, respectively. Photocatalytic degradation of Trypan blue (TB) was studied at different parameters such as pH, catalyst dosage, initial concentration, and contact time. The results showed that, at initial dye concentration of 20 ppm, pH = 2, and using 0.03 g of Ag3PO4/G/SiO2 as a photocatalyst, the degradation percent of TB dye in the aqueous solution was 98.7% within 10 min of light exposure. Several adsorption isotherms such as Langmuir, Freundlich, and Temkin adsorption isotherms have been tested in addition to the photocatalytic degradation kinetics. Both catalysts were found to follow the Langmuir isotherm model and pseudo-second-order kinetic model. Finally, the possible photocatalytic performance mechanism of Ag3PO4/G/SiO2 was proposed.

Exploring the novel environmentally friendly dye degradation mechanism of NiO-Polypyrrole polymer nanocomposites in degrading the organic pollutants under sunlight

<p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:115%"><span style="font-family:Calibri,sans-serif"><span lang="en-AE" style="font-size:12.0pt"><span style="line-height:115%"><span style="font-family:"Times New Roman",serif">According to estimates, around 15-50% of textile dyes fail to adhere to the fabric during the dyeing process, resulting in their discharge into wastewater. This wastewater is often used for agricultural irrigation in impoverished nations which harms plant germination and development. In this study, polymer composites of Polypyrrole (PPy) and nickel oxide (NiO) nanocomposites were synthesized via the hydrothermal method with different concentrations (250 mg, 500 mg, and 75 0mg) and their composite samples were employed as catalysts to degrade the anionic-brilliant blue and the cationic-crystal violet dye under 120 mins of sunlight irradiation. The process of degrading BB and CV dyes utilising nano catalysis was analysed using a pseudo-first-order kinetics model. The findings indicate that the degradation of the anionic dye is more efficient than that of the cationic dye under exposure to sunlight. Hence, the presence of NiO NPs and the NiO-PPy nanocomposite significantly impact their photocatalytic activity in degrading BB and CV dyes, achieving an impressive efficiency of around 96.99% and 89.96% respectively. Moreover, its stability has also been studied for over five cycles.</span></span></span></span></span></span></p>

Magnetic heterogenization of supramolecular carbohydrates for the efficient adsorption of heavy metals removal from wastewater

BackgroundAs the high impact of heavy metals hazards for humans and the environment, providing a suitable method to remove heavy metals is of great importance. Recently, magnetic adsorbents have been developed for their ease of separation, high absorption efficiency, and cost-effectiveness has been expanding. On the other hand, hybridism adsorbents composed of a magnetic core and an organic branch amended with different functional groups such as –OH, –NH2, −SH, and –COOH have suitable potentials for heavy metal removals. MethodsIn this, a simple procedure for the preparation of β-cyclodextrin bonded Fe3O4@SiO2 (β-CD-SiO2@Fe3O4) was reported. The morphological, structural, and thermal stability characteristics were investigated by the XRD, SEM, EDS, FT-IR, and TGA-DTA techniques. Next, the potential of β-CD-SiO2@Fe3O4 in the absorption of Cd2+ and Pb2+ ions from wastewaters was investigated. The effect of various parameters such as pH, adsorbent dosage, Pb/Cd concentration, and the temperature was investigated on the absorption of Cd2+ and Pb2+ heavy metal ions. Significant findingsThe maximum adsorption was achieved when pH = 6.5, heavy metal ion concentration (250 mg/L), and adsorbent dosage (0.075 g) at room temperature was used. The adsorption process could be described by kinetic models and the pseudo-second-order model was well-matched. The maximum adsorption capacities of Pb2+ and Cd2+ were obtained at 160 and 159.33 mg/g respectively. The negative value of ΔG indicates the spontaneity of the absorption process. The negative values of ΔH and ΔS show the exothermic nature of the absorption reaction.

Research on Collision Restitution Coefficient Based on the Kinetic Energy Distribution Model of the Rocking Rigid Body within the System of Mass Points

Research on Collision Restitution Coefficient Based on the Kinetic Energy Distribution Model of the Rocking Rigid Body within the System of Mass Points

Surfactant-Modified Bolivian Natural Zeolite for the Adsorption of Cr (VI) from Water

The present study reports the surfactant modification of Bolivian natural zeolite with hexadecyltrimethylammonium bromide (HTDMA-Br) for the adsorption of hexavalent chromium Cr (VI) anions from water. The surfactant-modified natural zeolite was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms, and Fourier-transform infrared spectroscopy (FTIR) to analyze the effect of its modification with HTDMA-Br and to verify its charge on the zeolite surface. We report a maximum adsorption capacity of 17 mg/g of Cr (VI) anions, surpassing the findings of some of the previous investigations on surfactant-modified natural zeolites of different geological origins. The analysis of the equilibrium data described the Cr (VI) anions adsorption by Langmuir isotherm and the pseudo second-order kinetic model. In addition, thermodynamics revealed an exothermic adsorption. Furthermore, anion exchange, electrostatic attraction, and chemical reduction were indicated to be dominating sorption mechanisms by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) characterization techniques.

Simulation of lower Cambrian oil and gas generation and phase evolution process in ZH1 of Tazhong area

The Lower Cambrian petroleum system in the Tarim Basin has undergone multiple periods of tectonic movements, leading to successive hydrocarbon expulsion events and adjustments. The complex process of hydrocarbon accumulation occurred under deep burial conditions, persisting at depths of nearly 6,000 m over an extended period. This has resulted in the current occurrence of various phases including light oil, condensate, and gas in the deep-ultradeep strata of the Tarim Basin. The intricacies of formation of hydrocarbon accumulations and phase evolution have posed challenges to understanding the accumulation mechanisms and enrichment patterns of the Cambrian in the Tarim Basin, consequently lowering the success rate of oil and gas exploration. Such characteristics of multi-stage accumulation and adjustment are prevalent in deep hydrocarbon systems. Therefore, based on data from Well ZH1 in the Tazhong Uplift, combined with basin simulation, Compositional kinetics model, and PVT performance simulation, this study investigates the hydrocarbon generation and phase evolution processes in the deep hydrocarbon systems of the Tazhong Uplift. The results indicate that Well ZH1 entered the hydrocarbon generation peak during the Late Ordovician, followed by secondary cracking as the predominant hydrocarbon evolution process. Hydrocarbon fluids within the Lower Cambrian reservoir transitioned into the condensate phase towards the end of the Cambrian, with increasing depth resulting in higher gas-oil ratios and a decreasing trend in viscosity and density.

Fractional neutron point kinetics model for reactivity transients of the NuScale and comparison with the classical kinetics approach

In this work, the behavior of the neutron and natural circulation parameters for Reactivity Transients in the PWR reactor called NuScale are analyzed through the novel system equations. It model includes non-integer and ordinary order differentials coupling the neutron point kinetic with the thermos-hydraulic core of the reactor. Transient processes of increase and decrease of the feed flow and the coolant inlet temperature are analyzed to identify the feedback of the thermohydraulic effects with the neutron phenomena in a non-integer order scheme. In the results, it is observed that for short times the power and reactivity have the same behavior with the classical model and the non-integer order model for all values of the anomalous diffusion coefficient simulated. However, for long times of simulation, there is more reactivity and less power, in contrast to the classical model, when reducing the value of the anomalous diffusion coefficient these counter-intuitive effects are increased. Additionally, a delay is observed between the change in reactivity and power. In conclusion, it is observed that sub-diffusive processes are relevant when there are slow changes in reactivity, which can be analyzed through the Fractional Order Neutron Density Equation.

Immobilization of multilayer sodium alginate/polysaccharide antibacterial material composite beads as glufosinate controlled release matrices

To find a new way to slow down the release of glufosinate (GA) pesticide and to solve the susceptibility to decomposition by soil microorganisms, a series of novel antibacterial polysaccharide-based sustained release beads (PSRB) were prepared. The PSRB was prepared by immobilization of GA loaded polysaccharide-based chitosan quaternary ammonium salt (PS-HACC) microcapsules in the core and layers of the multilayer sodium alginate beads. The PSRB was characterized by FI-IR spectroscopy, XRD, SEM, and BET to reveal their composition and surface morphology. The optimal conditions of the slow release beads were as follows, the concentration of Ca2+, pH, temperature and the coating layer number was 0.1 mol/L, 7, 25 °Cand 3, respectively. The kinetic study showed that the slow release of PSRB was in accordance with the Higuchi kinetic model, and the FI-IR and XRD analyses revealed that the PS-HACC and GA were successfully cross-linked to the PSRB. BET showed that PSRB were greater than PSRB3 at surface area, pore volume and pore size. Inhibition circles experiments demonstrated that WPSRB3 has good antibacterial activity. The weed control in soybean with PSRB3 application is perfect and the weed control cycle is long. Therefore, this technology can provide a potential way to control GA release, improve utilization efficiency, reduce pesticide use and environmental pollution, and at the same time, provide a potential way to achieve ecological agriculture.

Designing silver nanoparticles impregnated acacia and tragacanth gum based copolymeric hydrogels for drug delivery applications

The current study investigates the utilization of gum acacia (GA) & tragacanth gum (TG) for the synthesis of silver nanoparticles (NPs) and their subsequent incorporation into hydrogels for potential applications in drug delivery (DD). Cefoperazone, an antibiotic drug, was encapsulated into hydrogels to enhance their antimicrobial activity. Copolymers were characterized by UV–Vis, TEM, FESEM, AFM, XPS, XRD, FTIR, TGA and DSC techniques. UV–Vis spectroscopy revealed the formation of NPs at a wavelength of 436 nm with an optical density of 2.65. TEM images depicted AgNPs with an average size of 37.29 ± 7.25 nm with their uniform distribution. XRD analysis demonstrated distinct crystalline peaks at 2θ = 38.34o, 43.80o, 64.60o and 77.42o attributed to AgNPs. XPS peaks observed at 368 & 374 eV, corresponding to the 3d5/2 and 3d3/2 modes of silver, respectively, confirmed the incorporation of AgNPs in the polymer matrix. Hydrogels demonstrated pH responsive sustained release of cefoperazone. The diffusion mechanism was non-Fickian and described by the Higuchi kinetic model. In the DPPH assay, copolymers exhibited a 32.36 % inhibition of free radicals, whereas in the F–C reagent assay, antioxidant activity was measured as 22.25 μg equivalent of gallic acid. The copolymers displayed blood compatible nature, as evidenced from haemolysis (2.11 ± 0.03 %) and thrombogenicity (74.71 ± 1.63 %) results. The interactions of copolymer with intestinal membrane attributed to mucoadhesive properties and required detachment force of 55.30 ± 2.80 mN to separate from the biological membrane. Growth of E. coli, P. aeruginosa and S. aureus bacteria was inhibited by copolymers with and without antibiotic drug. These characteristic properties of copolymers make them ideal materials for DD carriers.

Considerations for fatty acids in standardized reference diet for parthenogenetic marbled crayfish Procambarus virginalis model organism

Fatty acid accumulation was studied in the parthenogenetic all-female marbled crayfish Procambarus virginalis using six arbitrarily designed experimental feeds and related to individuals with glair glands (sexual maturity) after 100 days of ad libitum feeding at 21 °C, including gravid females from the wild as a reference. Fatty acids 16:0 and 18:1n-9 comprised 40% of the total amount of fatty acids and tended to up-concentrate in bodies. Shorter chain 14:0 depleted from feed to body. Across diets, there was a concomitant decrease in precursor fatty acid and increase in product fatty acid, such as reinforcements in monounsaturated fatty acid (18:1n-9), eicosanoid precursors 20:4n-6 (arachidonic acid, ARA) and 20:5n-3 (eicosapentaenoic acid, EPA) in-vivo, but not 22:6n-3 (docosahexaenoic acid, DHA) except when deficient in CHI or CHI + SPI diets. Saturation kinetics modeling (R2 0.7–0.9, p < 0.05) showed that when the ARA share is ~ 1%, the EPA share is ~ 8%, and the DHA share is ~ 2% in the food lipids, the accumulation of fatty acids in body lipids levels off. The lowest DHA in the CHI (0% glair glands) or CHI + SPI (0–3.9% glair glands) diets, and the lowest ARA in SER (0% glair glands) or SER + SPI (0–3% glair glands) diets, were synchronous with negligible sexual maturity despite a wide range of observed specific growth rates (2.77–3.60% per day), body size (0.44–0.84 g), ≤ 5% crude lipid and 40–46% crude protein feed. The FISH and SHRIMP diets (56% protein, 11–14% lipid) with the highest ARA, EPA, and DHA together seem to be the most conducive diets for sexual maturity (up to 20% of individuals with glair glands). We propose a fatty acid profile mimicking the FISH or SHRIMP diets as a starting point for designing the lipid content required in the marbled crayfish standardized reference diet.

Injectable vancomycin-loaded silk fibroin/methylcellulose containing calcium phosphate-based in situ thermosensitive hydrogel for local treatment of osteomyelitis: Fabrication, characterization, and in vitro performance evaluation.

The conventional treatment of osteomyelitis with antibiotic-loaded nondegradable polymethylmethacrylate (ATB-PMMA) beads has certain limitations, including impeded bone reconstruction and the need for secondary surgery. To overcome this challenge, this study aimed to develop and characterize an injectable vancomycin-loaded silk fibroin/methylcellulose containing calcium phosphate-based in situ thermosensitive hydrogel (VC-SF/MC-CAPs). The VC-SF/MC-CAPs solution can be easily administered at room temperature with a low injectability force of ≤30 N and a high vancomycin (VC) content of ~96%. Additionally, at physiological temperature (37 °C), the solution could transform into a rigid hydrogel within 7 minutes. In vitro drug release performed under both physiological (pH 7.4) and infection conditions (pH 4.5) revealed a prolonged release pattern of VC-SF/MC-CAPs following the Peppas-Sahlin kinetic model. In addition, the released VC from VC-SF/MC-CAPs hydrogels exhibited antibacterial activity against Staphylococcus aureus for a period exceeding 35 days, as characterized by the disk diffusion assay. Furthermore, at pH 7.4, the VC-SF/MC-CAPs demonstrated >60% degradation within 35 days. Importantly, when exposed to physiological pH conditions, CAPs are transformed into bioactive hydroxyapatite, which benefits bone formation. Therefore, VC-SF/MC-CAPs showed significant potential as a local drug delivery system for treating osteomyelitis.