Chemical Alteration Research Articles

Classification of Alzheimer’s dementia EEG signals using deep learning

Alzheimer’s dementia (AD) is a predominant neurological disorder arising from corruptions in brain functions and is characterized by a chronic or progressive nature. While the precise etiology of dementia remains incompletely elucidated, its manifestation is frequently associated with discernible structural and chemical alterations in the brain. Living with dementia significantly impacts individuals’ daily lives due to the resultant loss of cognitive functions. This study presents a novel method to monitor and detect AD using advanced signal processing applied to electroencephalography (EEG) signals. The intrinsic time-scale decomposition (ITD) algorithm is employed to extract proper rotation components (PRCs) from EEG signals, utilizing a 5-second EEG segment duration. The proposed method is compared with the detection of 5-second raw EEG segments using a custom one-dimensional convolutional neural network (1D CNN). Additionally, four different quartiles (Quartile 1 (Q1), Q2, Q3, and Q4) of EEG signals are considered to identify the most significant contributor to AD. Experimental results demonstrate that the ITD-based approach yields better detection performance compared to using raw EEG signals. The most promising result is achieved by the EEG-PRCs method in Q1, with an accuracy of 94.00%, sensitivity of 93.50%, and specificity of 93.90%. In contrast, the highest-performing result of the raw EEG segments method is in Q2, with an accuracy of 88.40%, sensitivity of 89.10%, and specificity of 87.60% in terms of detecting AD.

Alterations of throughfall and stemflow chemistry by vegetation in China: Insights from a machine learning based meta-analysis

In vegetated ecosystems, the chemical composition of rainwater is strongly altered after gross rainfall (GR) partitioning into throughfall (TF) and stemflow (SF) before entering the under-canopy soil. However, quantitative syntheses of the chemical alteration are lacking, rendering an insufficient comprehension of its overarching patterns and magnitudes. Here, we furnish a comprehensive dataset related to the chemistry of rainfall partitioning by vegetation in China compiled from 131 peer-reviewed papers published between 1988 and 2023. A meta-analysis was conducted to assess the chemical alterations as GR partitions into TF and SF. We discerned a marked acidification effect in SF but not in TF, with the pH being significantly lower in SF than in GR. Additionally, we observed a persistent concentration-based chemical enrichment of total nitrogen (TN) and total phosphorous (TP) as well as 12 commonly reported nutrient-ions (except for Cu2+) in both TF and SF, with SF generally exhibiting a greater degree of chemical enrichment than TF. Using a machine learning method (boosted regression trees), we identified the key drivers from twelve biotic and abiotic predictor variables on the effect sizes of pH, TN, TP, and each nutrient-ion, and further elucidated the prevalent non-linear partial effects of these key drivers on the magnitude of chemical alterations. For instance, three predictor variables were identified as key drivers for the effect sizes of TN for SF, with a descending relative influence of diameter at breast height (56.9 %; positive effect), Human Footprint (16.5 %; positive), and bark texture (14.0 %; stands with mixed bark textures exerting a greater impact). Our study has significant implications for an accurate estimation of nutrient budgets in vegetated ecosystems throughout China, contributes to a deeper understanding of the intricate ways in which biotic and abiotic predictors influence chemical alterations in rainfall partitioning, and aids in evaluating forest health and developing sensible forest management strategies.

Investigation of the Chemical Changes from N-Doped Graphene and MOF to N-G/MOF Composites for the Enhancement of Electrocatalytic Properties

N-doped graphene (N-G) materials showed high potential as electrocatalysts for oxygen reduction reaction (ORR) in electrochemical energy systems and increasingly gaining ground as alternatives to the expensive and degradation-prone Platinum Group Metal (PGM)-based electrocatalysts. Numerous studies demonstrated that as N-G materials are integrated with Metal-Organic Frameworks (MOFs), the N-G/MOF composites exhibited higher electrocatalytic activities than the individual precursors; on several occasions, even higher than the PGM-based ones. In this essence, it is crucial to analyze and understand the chemical changes that occur through the integration of N-G and MOF, as these changes play key roles in enhancing electrocatalytic properties of the materials by introducing different electrochemically active sites. To investigate such chemical changes, we have synthesized an N-G/MOF composite by integrating an N-G with ZIF-8 (which is the most studied member of the MOF family) following a facile mechanochemical wet ball milling process. In the electrochemical characterization, the N-G/MOF composite performed better than N-G and ZIF-8 for ORR catalysis by generating a higher cathodic current density.Multiple samples of N-G, ZIF-8, and N-G/MOF composite were analyzed by X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy to detect the changes in elemental ratios, chemical bonds, and chemical functional groups from the precursors (N-G and ZIF-8) to the N-G/MOF composite. An increase in the elemental Nitrogen (N) ratio was observed in N-G/MOF compared to its precursors; which signifies an increased N-doping ratio in the material which is advantageous for ORR catalysis. The XPS C 1s spectra of N-G/MOF shifted to a higher binding energy (~1eV) compared to the precursors indicating an overall increase in the oxidation states of Carbon (C) atoms in the material which could facilitate oxygen molecules’ adsorption better on these sites at the beginning of ORR process. Comparing the analyzed XPS N 1s spectra revealed an increased relative ratio of the Pyridinic-N functional group in N-G/MOF, which also partly justifies the composite’s enhanced ORR electrocatalytic performance. FTIR analysis revealed interactions between methyl groups (-CH3) of ZIF-8 with oxygen functional groups (i.e. -OH) of N-G while forming the N-G/MOF composite. Besides, a transition from methyl groups (-CH3) to methylene group ( >CH2) was evident during the synthesis, increasing charge density near those C atoms of the N-G/MOF which can as well be advantageous for ORR electrocatalysis. The combined impact of these chemical alterations from N-G and ZIF-8 to N-G/MOF yielded a synergistic effect, elucidating its superior electrocatalytic properties. The findings of this experimental investigation provide insights into the chemical reasons for the enhancement of electrocatalytic properties of N-G/MOF composites; and hereby offer guidance to the design and optimization endeavors of novel catalysts with N-G and MOF materials for diverse electrochemical applications.

Sustained-Release Microspheres of Cyclodextrin-Resveratrol Complex Using Fenugreek Galactomannan Hydrogels: A Green Approach to Phytonutrient Delivery.

Food matrices are becoming increasingly complex with the impregnation of phytonutrients with health-beneficial pharmacological effects. Herein, we report the preparation, characterization, and functional application of soluble and stable microspheres of trans-resveratrol (t-RES) developed through a water-based green process involving cyclodextrin (CD) and fenugreek galactomannan (FG). Spectroscopic and thermodynamic calculations identified γ-CD as the best CD to form a stable cyclodextrin-resveratrol inclusion complex (CD-R, 49-fold enhanced solubility); however, it exhibited a burst release profile. The sustained release of resveratrol was achieved by further encapsulating the inclusion complex within the fenugreek galactomannan hydrogel scaffold by a gel-phase dispersion process, resulting in an amorphous powder (FG-CD-R) as evident from powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) studies. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) studies confirmed the formation of the inclusion complex with no chemical alterations. When dissolved in water, FG-CD-R swelled and released stable cuboid structures with an average particle size of 500 ± 53 nm with a zeta potential of -52 ± 5.3 mV. FG-CD-R demonstrated a sustained-release profile upon in vitro release studies. Accelerated study demonstrated its stability for a shelf-life of two years. Further it was shown to be suitable for the preparation of transparent gummies with improved sensory attributes compared to unformulated t-RES. In summary, FG-CD-R is simple to prepare and easily scalable, providing a sustained-release t-RES with a natural, food-grade, and clean label status (non-genetically modified, allergen-free, vegan, and free from residual solvents) for nutritional applications.

Influence of fracturing fluids on shale matrix permeability and micro-mechanical properties after chemical interactions

Geochemical interactions between shale and hydraulic fracture fluids (HFFs), principally mineral dissolution and precipitation, can result in alteration of matrix permeability and tendency of proppant embedment, ultimately impacting hydrocarbon migration through the shale formation. This study aimed to quantify changes of core permeability and micromechanical properties after shale-HFF chemical interactions. Extent of chemical alteration of the solid phase was characterized by synchrotron X-ray fluorescence mapping, micro-computed tomography, and scanning electron microscopy. Post-reaction brine was evaluated for elemental concentrations. Both low-carbonate and high-carbonate shale exhibited carbonate dissolution, an iron oxidation zone, and barite precipitates partially infilling secondary porosity. These reactions were more obvious in the high-carbonate shale but extended further into the low-carbonate shale. Pulse-decay permeability measurements generally revealed increase in permeability after reactions, whereas hardness and modulus reduction were observed only in reaction zones of high carbonate shale. Inevitable heterogeneity of natural shale samples resulted in large deviations in hydromechanical measurements both on the core scale and on the microscale.

Integrating geochemical insights and remote sensing for enhanced identification of hydrothermal alterations in the Igoudrane region, Anti-Atlas, Morocco

The Moroccan Anti-Atlas is distinguished for its significant mining potential. The Igoudrane region, which is the focus of this study, is located within the Imiter inlier, one of the notable inliers of the eastern Anti-Atlas. The current study aims to evaluate the mineralogical and geochemical composition of the rocks in the Igoudrane area using the ICP-MS with 4 acids, besides identifying the hydrothermal alteration indexes using major elements provided by the geochemical data, and remote sensing techniques. The study was accomplished using the thin sections for mineralogical description, as well as the ICP-MS with 4 acids, which provides data on major, trace, and rare earth elements. The alteration indexes employed were the Ishikawa alteration index (AI), the Chlorite Saturation Index (CSI), the Sericite Saturation Index (SSI) and the Alteration Intensity coefficient (AIC). These indexes were complemented by a chloritization and sericitization mapping using the SWIR-VNIR data of ASTER. We employed the band ratios of chlorite [(B6 + B9)/(B7 + B8)] and sericite [(B5 + B7)/B6], achieving an accuracy of 80.95% for sericite and approximately 85.71% for chlorite. The mineralogical and geochemical study revealed the presence of granodiorites, granites, monzonites, monzo-diorites, diorites, gabbro, and gabbro-diorites, andesites, rhyolites, and trachydacites. These rocks belong to a highly potassic calc-alkaline and peraluminous series, which are fairly typical of granitoids of mixed origin. The plutonic rocks of Igoudrane were formed across diverse geodynamic contexts, ranging from pre-plate to post-collisional settings, and the volcanic rocks were emplaced in geodynamic settings, which are island arcs or active continental margins. The quasi-positive correlation observed in the Al vs. CSI and SSI diagrams reveals that higher aluminum content is linked to increased chloritization and sericitization intensities. Furthermore, The AIC values of the Igoudrane rocks were ranging between 52.25% and 67.53%, indicating that they have undergone moderate to high chemical alteration. The remote sensing techniques employed improve the distribution of these alteration minerals.

Rock-to-Pharma: Characterization of Shale Oil-Based Nonbiological Complex Drugs along the Production Process by High-Resolution Mass Spectrometry.

Antibiotic resistance has become a primary concern in medicine because of the overuse and misuse of classical pharmaceuticals. Recently, nonbiological complex drugs (NBCDs) have gained interest for their complex pharmacological profiles. Bituminosulfonates, which have lately been tentatively allocated toward NBCDs, are pharmacologically well-studied and show low potential in resistance development. However, molecular composition knowledge is limited. With this work, we present a comprehensive approach to investigate the manufacturing process of complex pharmaceuticals like bituminosulfonates on a molecular level via Fourier-transform ion cyclotron resonance mass spectrometry. The application of various hyphenations and ionization techniques comprehensively covers the entire mass and polarity range of the matrix, and the high sensitivity enables the identification of significant and minor chemical alterations caused by the multistep manufacturing process. The distillation of the shale crude oil eliminates highly aromatic PAH and PASH constituents. ESI(-) revealed strong PAH- and PASH-sulfonate formation after reacting the shale oil distillate with sulfuric acid. Increasing alkylation reduced the sulfonation yield, instead causing oligomerization side reactions, as observed by APPI analysis. Furthermore, multidimensional gas chromatography coupled with high-resolution mass spectrometry verified core structural motifs. With this work, we demonstrate the high potential of FT-ICR MS in NBCD process analysis. The results also give valuable information for future pharmacological investigations focusing on specific compound classes or properties.

Soil Chemical Alteration Due to Treated Swine Wastewater Application in a Semi-arid Area in Southeastern Brazil

Soil Chemical Alteration Due to Treated Swine Wastewater Application in a Semi-arid Area in Southeastern Brazil

Encapsulation of Peperomia pellucida (L.) kunth leaf extract for postharvest preservation of Malang apple (Malus sylvestris) at ambient storage

This study investigated the efficacy of edible coatings based on encapsulated Peperomia pellucida leaf extract to extend the shelf life of Malang apples. An edible coating was developed by encapsulating P. pellucida leaf extract using a chitosan-STPP matrix. The optimum encapsulation efficiency observed of polyphenols and flavonoids retention was 86.25% ± 0.02 and 83.30% ± 0.04, respectively. It achieved by 2.5% chitosan, 2% STPP, and 3.5% extract in formula. The encapsulated extract was further applied to Malang apples as edible coated using varying dipping times and stored for 15 days at ambient temperature. Evaluation parameters on coated Malang apples included hardness, weight loss, pH, moisture content, and color change. A 1-min dipping time of the encapsulated extract was found to be optimal, effectively reducing physical and chemical alterations and enhancing the shelf-life quality of the apples. Therefore, the edible coating derived from encapsulated P. pellucida leaf extract presents a promising alternative for preserving Malang apples.

Polystyrene nanoplastics-induced intestinal barrier disruption via inflammation and apoptosis in zebrafish larvae (Danio Rerio)

Plastics are one of the most pervasive materials on Earth, to which humans are exposed daily. Polystyrene (PS) is a common plastic packaging material. However, the impact of PS on human health remains poorly understood. Therefore, this study aimed to identify intestinal damage induced by PS nanoplastics (PS-NPs) in zebrafish larvae which have a high homology with humans. Four days post fertilization (dpf), zebrafish larvae were exposed to 0-, 10-, and 50-ppm PS-NPs for 48 h Initially, to ascertain if 100 nm PS-NPs could accumulate in the gastrointestinal (GI) tract of zebrafish larvae, the larvae were exposed to red fluorescence-labeled PS-NPs, and at 6 dpf, the larvae were examined using a fluorescence microscope. Analysis of the fluorescence intensity revealed that the GI tract of larvae exposed to 50-ppm exhibited a significantly stronger fluorescence intensity than the other groups. Nonfluorescent PS-NPs were then used in further studies. Scanning electron microscopy (SEM) confirmed the spherical shape of the PS-NPs. Fourier-transform infrared spectroscopy (FT-IR) analysis revealed chemical alterations in the PS-NPs before and after exposure to larvae. The polydispersity index (PDI) value derived using a Zetasizer indicated a stable dispersion of PS-NPs in egg water. Whole-mount apoptotic signal analysis via TUNEL assay showed increased apoptosis in zebrafish larval intestines exposed to 50-ppm PS-NPs. Damage to the intestinal tissue was assessed by Alcian blue (AB) and hematoxylin and eosin (H&E) staining. AB staining revealed increased mucin levels in the zebrafish larval intestines. Thin larval intestinal walls with a decrease in the density of intestinal epithelial cells were revealed by H&E staining. The differentially expressed genes (DEGs) induced by PS-NPs were identified and analyzed. In conclusion, exposure to PS-NPs may damage the intestinal barrier of zebrafish larvae due to increased intestinal permeability, and the in vivo gene network may change in larvae exposed to PS-NPs.

Enhancing cellulose acetate biodegradability in cigarette filters: an in-depth analysis of thermal alkaline pretreatment, microbial dynamics, and breakdown pathway prediction

BackgroundThe demand for bioplastics has increased exponentially as they have emerged as alternatives to petrochemical plastics. However, there is a substantial lack of knowledge regarding bioplastic degradation. This study developed a novel pretreatment method to improve the accessibility of a bioplastic substrate for biodegradation. In this study, cellulose acetate, a bioplastic found in the world’s most littered waste, e.g. cigarette filters, was selected as a potential substrate. Before anaerobic digestion, three thermal alkaline pretreatments: TA 30 °C, TA 90 °C, and TA 121 °C, were used to evaluate their effects on the chemical alterations of cellulose acetate.ResultThe ester groups in cellulose acetate were significantly reduced by the TA 30 °C pretreatment, as seen by a decrease in C = O stretching vibrations and shortening of C − O stretches (1,270 ∼ 1,210 cm− 1), indicating effective removal of acetyl groups. This pretreatment significantly enhanced cellulose acetate biodegradability to a maximum of 91%, surpassing the previously reported cellulose acetate degradation. Methane production increased to 695.0 ± 4 mL/g of volatile solid after TA 30 °C pretreatment, indicating enhanced cellulose acetate accessibility to microorganisms, which resulted in superior biogas production compared to the control (306.0 ± 10 mL/g of volatile solid). Diverse microbes in the anaerobic digestion system included hydrolytic (AB240379_g, Acetomicrobium, FN436103_g, etc.), fermentative, and volatile fatty acids degrading bacteria (JF417922_g, AB274492_g, Coprothermobacter, etc.), with Methanobacterium and Methanothermobacter being the sole hydrogenotrophic methanogens in the anaerobic digestion system. Additionally, an attempt to predict the pathway for the effective degradation of cellulose acetate from the microbial community in different pretreatment conditions.ConclusionsTo the best of our knowledge, this is the first study to estimate the maximum cellulose acetate degradation rate, with a simple and cost-effective pretreatment procedure. This approach holds promise for mitigating the environmental impact of cellulose acetate of cigarette filters and presents a sustainable and economically viable waste management strategy.

Quartz grain microtextures of Holocene sebkhas sediments in southeast Tunisia: Implications for sedimentary processes and depositional environments

Detrital quartz grains extracted from sebkha sediments in southeastern Tunisia underwent scanning electron microscopy analysis to identify sediment sources and assess the influence of the saline environment on the grains. Core sediments collected from Sebkha el Melah and Sebkha Mhabeul cover the last 5000 and 2000 BP, respectively. The uppermost Unit III, present in both cores, exhibits two distinct facies based on the mechanical microtextures of its quartz grains. The aeolian facies sediments are characterized by quartz grains with rounded outlines, upturned plates, and crescentic percussion marks. In contrast, the fluvial facies sediments are associated with quartz grains featuring subangular outlines, v-shaped percussion cracks, conchoidal fractures. Observations on the quartz grains of the sebkhas suggest multiple transportation and processing events, indicating long-distance transport and rapid deposition rates. The majority of quartz grains appear to originate from the surrounding terrain, reflecting the dynamic geological history of the region. This study delves into the connection between microtexture variations on quartz grain surfaces and specific historical climatic conditions in the sebkhas. By examining geochemical variations along the cores, facies with elevated salt concentrations corresponding to warmer periods reveal extensively weathered quartz grains. This substantial chemical alteration is evident through microtextures such as oriented etch pits, anastomosed dissolution networks and solution crevasses. The profound dissolution has significantly impacted the quartz lattice, resulting in the decomposition of the grains and the formation of "cauliflower" or "spongy" shapes, erasing prior microtextures. Conversely, during less warm periods, quartz dissolution was less severe, thereby preserving microtextures.Sand grain surfaces are notably sensitive to both transport processes and variations in the physicochemical environment. In the hypersaline and confined environments of sebkhas in southeastern Tunisia, potent post-sedimentary processes can obliterate and obscure the original microtextures recorded on grains from previous environments due to highly fluctuating physicochemical conditions.

Investigation of an Indian Site with Mafic Rock for Carbon Sequestration.

The increasing extent of greenhouse gas emissions has necessitated the development of techniques for atmospheric carbon dioxide removal and storage. Various techniques are being explored for carbon storage including geological sequestration. The geological sequestration has various avenues such as depleted oil and gas reservoirs, coal-bed methane reservoirs, and mafic and ultramafic rocks. Different trapping mechanisms are in play in these subsurface storage systems. In these sequestration sites, the mafic and ultramafic rocks are best suited for long-term and effective sequestration as they comprise minerals, conducive for chemical alteration, forming stable carbonates. However, these sites often suffer from distinct disadvantages of injectivity issues due to their low permeability and porosity. This study investigates the potential of sequestration in the rock samples obtained from one such site located in India. The rock samples are first characterized using various techniques including X-ray fluorescence, X-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy (FESEM). The mineralogical characterization shows that the rock sample contains approximately 10% of diopside. The samples were put in the reactor chamber comprising CO2, which were then investigated using FESEM analysis. Additionally, a reservoir block simulation using commercial software was conducted with the representative minerals in the sample to evaluate the CO2 sequestration potential. The simulation result suggests the formation of magnesite which corresponds to a major part of CO2 mineral trapping. The reduced injectivity due to low porosity and permeability in this rock can be addressed using hydraulic fracturing. The geomechanical behavior of the rock sample for hydraulic fracturing is studied using the Brazilian disc test. The Monte Carlo-based uncertainty analysis was conducted using the tensile strength data of the sample. Results suggest that the most likely fracturing pressure is 2100 psi for this rock sample.

Poly(Ethylene Glycols) to Facilitate Celloidin Removal for Immunohistochemical Studies on Archival Human Brain and Temporal Bone Sections.

Pathology repositories worldwide store millions of celloidin-processed human brain and temporal bone (TB) sections vital for studying central nervous system diseases and sensory organs. However, accessing these sections for modern molecular-pathological research, like immunohistochemistry, is hindered by the challenge of removing celloidin without damaging tissue. In this study, we explored the use of polyethylene glycols (PEGs), a class of non-hazardous, ethylene glycol oligomers, combined with an improved section mounting technique, to gently and effectively dissolve celloidin from sections archived for up to 40 years. Optimizing our protocol involved exploring celloidin dissolution kinetics in PEGs of varying molecular weights and terminations, as well as different temperatures. Low molecular weight PEGs, particularly PEG 200, were the most efficient celloidin solvent. Nuclear magnetic resonance (NMR) spectroscopy of celloidin-PEG 200 dissolution products revealed no chemical alterations, suggesting pure solvation without chemical modification. Because the solvation of celloidin in PEG was inhibited by proteins, we further developed a protein-free mounting protocol allowing complete celloidin removal in 30 to 60 minutes by immersing in PEG 200. In summary, our approach overcomes major methodological hurdles, rendering decades-old archival celloidin sections viable for immunohistochemical and other molecular biological techniques, while enhancing safety and workflow efficiency.

Oral administration of encapsulated catechin in chitosan-alginate nanoparticles improves cognitive function and neurodegeneration in an aluminum chloride-induced rat model of Alzheimer's disease.

The present study aimed to investigate the effect of catechin-loaded Chitosan-Alginate nanoparticles (NPs) on cognitive function in an aluminum chloride (AlCl3)-induced rat model of Alzheimer's disease (AD). The Catechin-loaded Chitosan-Alginate nanocarriers were synthesized through ionotropic gelation (IG) method. Physio-chemical characterization was conducted with the Zetasizer Nano system, the scanning electron microscope, and the Fourier transform infrared spectroscopy. The experiments were performed over 21 days on six groups of male Wistar rats. The control group, AlCl3 treated group, Catechin group, nanocarrier group, treatment group 1 (AlCl3 + Catechin), and treatment group 2 (AlCl3 + nanocarrier). A behavioral study was done by the Morris water maze (MWM) test. In addition, the level of oxidative indices and acetylcholine esterase (AChE) activity was determined by standard procedures at the end of the study. AlCl3 induced a significant increase in AChE activity, along with a significant decrease in the level of Catalase (CAT) and total antioxidant capacity (TAC) in the hippocampus. Moreover, the significant effect of AlCl3 was observed on the behavioral parameters of the MWM test. Both forms of Catechin markedly improved AChE activity, oxidative biomarkers, spatial memory, and learning. The present study indicated that the administration of Catechin-loaded Chitosan-Alginate NPs is a beneficial therapeutic option against behavioral and chemical alteration of AD in male Wistar rats.

Investigating the impact of thymol/ɤ-cyclodextrin concentrations on the properties of electrospun PLA/PVP nanofibers for packaging applications

This study focuses on the modification of Polylactic acid (PLA)/polyvinylpyrrolidone (PVP) nanofibers using thymol-loaded cyclodextrin (TC) to optimize their suitability for applications in food science and packaging. The researchers conducted a comprehensive investigation into the impact of TC concentration on the nanofiber morphology, chemistry, and functionality. Scanning electron microscopy (SEM) analysis revealed that the modification with TC led to a reduction in fiber diameter and an increase in bead formation compared to the unmodified nanofibers. Fourier transform infrared spectroscopy (FTIR) analysis confirmed chemical alterations resulting from TC incorporation. The mechanical properties of the nanofibers were significantly enhanced with increasing TC content, as demonstrated by increased tensile strength and reduced elongation. This indicates improved mechanical strength and resilience of the nanofibers. Furthermore, the modified nanofibers exhibited notable improvements in antioxidant and antibacterial activities. They demonstrated remarkable antibacterial efficacy against both E. coli and S. aureus. This suggests that the incorporation of TC enhanced the antimicrobial properties of the nanofibers. Thymol release from the nanofibers reached its peak at a TC concentration of 10 %. This indicates that the release of thymol can be optimized by adjusting the TC content in the nanofibers. Overall, the results of this study demonstrated improved properties such as moisture management, mechanical properties, and antimicrobial activity in the modified nanofibers. These findings highlight the suitability of TC-modified nanofibers for various applications in the food industry, particularly in food science and packaging.

Isolation, identification and screening of Polyurethane polymer degrading microbe isolated from contaminated site

The objective of this research was to isolate soil-based bacteria that may destroy polyurethane (PU). PU plays a crucial role in many parts of our daily life. Polyurethanes are a significant and adaptable group of synthetic polymers utilized in a wide range of industrial, automotive and medical sectors. Due of its widespread use and challenges in recycling or reusing, PU primarily becomes garbage. PU has been observed to be degraded by a variety of bacteria and fungi. The objective of this study was to isolate polyurethane degrading microbes from the soil sample. Two bacteria Bacillus subtilis and Pseudomonas aeruginosa and three fungi Aspergillus versicolor, Aspergillus fumigatus and Aspergillus Niger, were isolated and identified from the soil sample based on morphological and biochemical characteristics. In this study, the fungus Aspergillus versicolor shows the high degradation percentage on polyurethane film. Scanning electron microscopy and ATR-FTIR were used in this study to evaluate the surface and chemical alterations of PU.

Comprehensive batch studies on removal of fluoride from aqueous solution by acid and alkali-activated adsorbents prepared from Dal lake weeds: Mechanism, Kinetics and Thermodynamics

An efficient and economical way of eliminating fluoride from water is being investigated by employing the buoyant aquatic plant (Dal weed). Two post-pyrolysis chemical activation alteration techniques were implemented: acidic activation by employing sulfuric acid (H-activation) and alkaline activation using sodium hydroxide (OH-activation). The batch kinetic studies have been carried out considering varying starting fluoride levels such as 2–10 mg/L. The impact of diverse procedural factors, including dosage of Dal weed, starting fluoride level, pH and contact duration was observed to determine their influence on fluoride adsorption kinetics. Based on analyzed exploratory results, removal efficacy of 63% for the OH-activated carbon and 83% for H-activated carbon was achieved at commencing fluoride level of 10 mg/L, adsorbent dosage of 0.8 g, at 25 °C after 120 min. The maximal fluoride uptake capacity for H-activated carbon was observed to be 78.158 mg/g. Kinetic investigations showed that the Freundlich isotherm model provided a satisfactory match with an R2 value of 0.99. The reaction order nature adhered to kinetics resembling pseudo second order. Thermodynamic investigation revealed endothermic sorption, with negative ΔG indicating spontaneous fluoride uptake. In comparison, the positive number for ΔS suggested random behavior at the contact involving the adsorbent and adsorbate. The investigations into the regeneration capabilities of the adsorbent material revealed that even after undergoing for five consecutive cycles of adsorption and regeneration, the adsorbent exhibited an uptake potential of 45%. The presence of competing ions in the solution negatively impacted defluoridation efficacy, with the influence following the order of HCO3−< NO3−< Cl−< SO42−< PO43−.

Investigation on the interaction of NH3&CH4 co-activated char under reburning conditions

In the current global context, there is a pressing need to curtail greenhouse gas emissions, making the utilization of a coal and zero-carbon energy blend an imperative strategy for reducing carbon emissions from coal-fired power generation. The planar flame burner serves as a tool to simulate the temperature and atmospheric conditions within the reburning zone, facilitating extensive examination of the physical and chemical structural alterations, as well as the nitrogen oxide reduction potential, during NH3/CH4 activation for reburning pulverized coal. Experimental results underscore that blending high-activity fuels optimizes the combustion performance of coal char. Through the addition of NH3 and CH4, the NO reduction capability of coal char is bolstered by approximately 0.67 times compared to sole reliance on recirculating flue gas transport. Furthermore, NH3 introduction facilitates the conversion of C]O double bonds into C–O single bonds, rendering them more amenable to reduction by NO. While the joint influence of NH3 and CH4 does not significantly impact char particle size, it does foster the evolution of N-Q to N-5 and N-6 on the char surface. Furthermore, there was a significant increase in the BET-specific surface area, which rose by 50%. Additionally, the total pore volume increased by approximately 21.43%. The comprehensive understanding of NH3 and CH4 modified pulverized coal reburning technology holds significant promise for optimizing power plant operations and mitigating carbon dioxide and nitrogen oxide emissions.

Role of Fracture Roughness in Fracture Surface Evolution During Acidized Corefloods of Calcareous Shales

Summary During the hydraulic fracturing process, an acidic hydraulic fracturing fluid (HFF) is injected at high flow rates to break the rock and enhance its flow potential. This rock-fluid interaction induces both physical and chemical alterations on the fracture surface, resulting in the formation of a “reaction-altered zone.” Recent research has revealed that the depth of reaction penetration is minimal, and most changes occur on the fracture surface. To gain a deeper understanding of how fracture roughness affects fracture aperture change, in this work we adopt an experimental approach. Two similar samples of carbonate-rich Wolfcamp shale with calcite-filled fractures are selected. One sample is cut through the center creating a smooth fracture (SF), while the other is fractured by parting along the calcite-filled fracture, generating a rough fracture (RF). The fracture surface topography, mineral distribution, fracture aperture, and rock hardness are characterized before a reactive coreflood using an equilibrated acidic brine is conducted. The pressure drop across the core is measured, and the effluent is periodically collected and analyzed using mass spectrometry. The temporal changes in the fracture surface are observed by conducting physicochemical surface characterization after the coreflood. The results indicate that calcite dissolution is the primary chemical reaction occurring on the fracture surface, weakening it. Furthermore, this dissolution decreases the fracture roughness, which results in fracture closure and ultimately a decrease in the fracture conductivity. The most significant change in the fracture aperture is observed near the inlet. These results highlight the potential impact of fracture roughness on the mechanism of fracture evolution during acidized corefloods. Higher fracture roughness is associated with increased fines migration and a more significant overall change in fracture aperture during injection. This research provides valuable insights into the intricate processes at play during hydraulic fracturing and aids in understanding the dynamics of fracture growth in such conditions.