Specific Functional Groups Research Articles

Unlocking the medicinal arsenal of Cissus assamica: GC-MS/MS, FTIR, and molecular docking insights.

This study investigated the biochemical components present in the leaves of Cissus assamica. The primary aim was to analyze these components using advanced techniques and assess their potential therapeutic applications. Fourier Transform Infrared (FT-IR) spectroscopy, Gas Chromatography-Mass Spectrometry (GC-MS), and Mass Spectral analysis were employed to identify and characterize the compounds in Cissus assamica leaves. The mass spectra of each compound were compared with data from the Wiley and NIST libraries to determine their names, molecular masses, and chemical structures. FT-IR analysis identified characteristic functional groups by their specific frequencies. FT-IR spectroscopic analysis revealed significant molecular vibrations at frequencies of 3265.63, 2853.81, 1638.60, 1469.21, and 1384.95 cm⁻¹, indicating the presence of specific functional groups. The GC-MS analysis identified distinct compounds, such as "aR-Turmerone," "Curlone," "7,8-Epoxylanostan-11-ol, 3-acetoxy-," "13-Docosenamide, (Z)-," "Phenol, 3,5-bis(1,1-dimethylethyl)-," "9,19-Cyclolanostan-3-ol, 24,24-epoxymethano-, acetate," and "Quinoline-5,8-dione-6-ol, 7-[[(4-cyclohexylbutyl)amino]methyl]-." These compounds exhibited potential therapeutic applications. Their cytotoxic, antimicrobial, antidiarrheal, anti-hyperglycemic, and pain-relieving properties were evaluated by comparing them with reference ligands targeting specific receptors, including dihydrofolate reductase (DHFR), epidermal growth factor receptor (EGFR), kappa opioid receptor (KOR), glucose transporter 3 (GLUT 3), and cyclooxygenase 2 (COX-2). The results of this study suggest that Cissus assamica leaves contain bioactive compounds with potential therapeutic benefits for treating infections, diarrhea, hyperglycemia, and pain. However, further research is needed to conduct comprehensive phytochemical screening and establish the precise mechanisms of action for the crude extract or the plant-derived compounds.

Preparation of a surface molecularly imprinted thermo-sensitive polymer for selective trypsin capture

Molecularly imprinted polymers (MIPs) are innovative porous materials created through polymerization templating methods for highly selective, sensitive detection and separation of the desired chemical species, known as template molecules. Surface imprinting over nano-sized substrates with special functional groups is an effective approach for improving the mass transfer and rebinding capacity. In this study, we successfully performed surface imprinting using methacrylic acid (MAA) and thermoresponsive N-isopropyl acrylamide (NIPAm) as functional monomers on acrylic-functionalized silica nanoparticles and served as a Trypsin artificial receptor. The resulting Trypsin imprinted polymer exhibited a binding capacity of 1022.44 mg/g, surpassing the non-imprinted polymer’s capacity of 292.41 mg/g within 45 min. Moreover, the imprinting factor, the main influence factor in MIP performance, was 3.5, demonstrating the significant selectivity of the polymeric products. In addition, due to the temperature sensitivity of NIPAm the template removing process was simply done by changing pore size. The silica nanoparticles and the synthesized MIP particles had diameters of approximately 95 nm and 105 nm, respectively, with the polymer layer thickness being around 5 nm. The MIP adsorption model followed the Freundlich isotherm and pseudo-second-order kinetics resulting in efficiencies of 93.0 % and 95.4 %, respectively. The developed Trypsin imprinted polymer was reusable for four consecutive uses,demonstrating both resilience and selectivity towards Trypsin.

Impact of functional groups on aboveground biomass in alpine grassland communities

Alpine grasslands on the Tibetan Plateau (TP) are highly vulnerable to various treatments and face significant degradation risks due to global environmental changes. However, the response of these grasslands to different external treatments remains uncertain, and the patterns behind functional group responses are unclear, impeding our ability to restore alpine grasslands under changing climate. To address this gap, we compiled a comprehensive database of 797 experimental observations of alpine grasslands in the TP, classified these communities into four common functional groups (e.g., grass and sedge), and conducted a meta-analysis to evaluate the response of aboveground biomass (AGB) to nine different treatments (e.g., grazing and nitrogen addition). Meta-regression was used to analyze the changes in AGB with treatment intensity and duration. We also used functional group asynchrony and unevenness to describe the complementary effects (CEs) and selection effects (SEs) of communities under these treatments. We found that among all the nine treatments, grazing had the biggest negative impact on the alpine grassland community by reducing AGB by 40.3%, mainly through decreasing the biomass of grass and sedge. Conversely, nitrogen and phosphorus addition had the largest positive effect, increasing AGB by 39.4% mainly by promoting the growth of grass. However, the increase in AGB was not significant in the interactive experiments involving grazing and nitrogen addition. The unevenness of the community decreased as grazing time prolongs, simplifying the structure of the community, with severe nutrient losses and weakened CE, while nitrogen addition could rapidly increase the AGB of grass and enhance the SE. CE or SE of communities can be enhanced through the restoration of specific functional groups, favoring the recovery of vegetation. Our study also revealed the potential of nitrogen compensation for repairing the damage caused by overgrazing on alpine grasslands.

Temperature and pressure driven functionalization of graphene with hydrogen and oxygen via ab initio phase diagrams

Functionalized graphene has numerous applications due to its remarkable and tunable physicochemical properties. However, precise control of functionalization remains challenging as direct connections between defect and functional group stability on graphene as a function of treatment conditions are missing. Here, a systematic study of graphene functionalization with hydrogen and oxygen is performed using a combination of density functional theory and ab initio phase diagrams. The interplay between carbon defects (e.g. vacancies, Stone-Wales, 555–777) and functionalization (e.g. R-H, R-H2, R-O, R-OH, and R-COOH) is examined. Generally, the process of functionalizing graphene led to significantly more stable carbon defects. By calculating Gibbs free formation energies with varying temperatures and partial pressures of H2 and H2O, ab initio phase diagrams were constructed. These diagrams revealed that the applied hydrogen and oxygen chemical potentials can be balanced during treatment to generate six distinct structures: R-H, R-O, R-OH, and R-COOH on the basal plane; and R-O and R-H2 on a double carbon vacancy. Through this systematic study, both the treatment conditions conducive to the formation of specific functional groups on graphene are pinpointed and a range of stable and metastable graphene-based structures with applications in various fields are identified.

Wavelength-Selective Xanthene-Based Monochromophoric Photoremovable Protecting Groups for Tuning Soft Matter Material Properties.

Photocontrolled deprotection of specific functional groups has garnered significant interest over the past two decades. Notably, the selective deprotection of distinct groups based on wavelength has emerged as a prominent focus in recent research. The achievement of this objective has primarily involved the utilization of linker-based bichromophoric systems and diverse cocktail mixtures of photoresponsive protecting groups (PRPGs), each responsive to varying wavelengths of light. Herein, we present the first wavelength-selective monochromophoric system based on a hydroxanthene moiety, enabling the wavelength-selective release of two distinct functionalities under 450 and 600 nm light, respectively. The mechanism of the wavelength-selective photodegradation was thoroughly investigated by 1H NMR, UV-vis, and fluorescence spectroscopy, suggesting a proton-coupled electron transfer mechanism in the first photorelease step and electron transfer based arylmethyl type of photorelease in the second step. The utility of the xanthene-based wavelength-selective PRPGs was demonstrated in the multistep degradation of microparticles and dual-color tuning of polymer chain architecture, thus opening an avenue to design advanced photoreactive wavelength-controlled systems for applications in soft matter materials.

Electrochemical analysis of Yttrium chromate nanoparticles synthesized via green mediated combustion route

Yttrium Chromate (YCrO4) nanoparticles (YCNPs) were synthesized using a solution combustion method with a green extract (NeemLeaves extract as a reducing agent. The as-obtained NPs are allowed for calcination at 600 °C. The PXRD pattern showed Bragg reflections confirming the formation of a pure tetragonal phase of YC NPs belonging to the space group I 41/a m d:1. without impurity peaks. The surface morphology revealed smaller, irregularly sized, and shaped NPs with pores and hollows which is the characteristic of solution combustion synthesis. UV–visible spectroscopic analysis confirmed the various absorbance peaks. The energy band gap, determined from Wood and Tauc's plot, was 3.08 eV. FTIR analysis confirmed the presence of specific functional groups in the sample. Electrochemical analysis revealed a specific capacitance range of 61.52 to 40.18 F/g within the scan range of 10 mV/s to 50 mV/s which is due to Increasing scan rate reduces specific capacitance by limiting ion diffusion into deeper pores, favoring interaction with the surface, thus decreasing utilization of active sites and overall capacitance. Collectively, these findings suggest that YCNPs hold promise for practical applications in advanced energy storage devices.

Water structures in tip-charged carbon nanotubes.

Carbon nanotubes (CNTs) have potential applications in separation membranes and nanofluidic devices. It is well known that the behavior of water molecules confined in CNTs is affected by surface functional groups and external electric fields, leading to structural changes. The understanding of these structural changes of water within various CNTs is crucial, particularly in the context of material separation. While there have been many investigations into the effects of individual specific functional groups, a comprehensive understanding of the effect of these functional groups and the electric fields they generate on water molecules remains elusive. In this study, we investigate the properties of water molecules in tip-charged CNTs of (8,8), (10,10), and (12,12) chiral vectors with positive charges at one tip and negative charges at the other tip. Abstraction of ionized functional groups as tip charges enables a comprehensive understanding that is independent of individual functional groups. The symmetrically arranged tip-charges spontaneously generate a strong and symmetric electric field in the CNTs. However, the strength and directionality of the electric field are non-uniform and complex. In the interiors of (8,8) and (10,10) tip-charged CNTs, helical and square structures, which have disturbances caused by the non-uniformity of the electric field, are observed. The properties of the water molecules differed significantly in the center of the CNTs and near positive and negative charges, despite the electric field symmetry. In (12,12) tip-charged CNTs with 12 charges, a local ring structure is observed in the vicinity of negative charges but not in the vicinity of positive charges. It is concluded that the water structures in tip-charged CNTs have different characteristics from those in plain CNTs under a uniform electric field.

Application studies on MXene-based flexible composites

MXene is a novel two-dimensional layered nanomaterial with a very large specific surface area and abundant surface functional groups, endowing it with unique physical and chemical properties. MXene can be compounded with other functional materials to significantly improve the performance of MXene composites or broaden their application scope. Meanwhile, with the development of flexible composite preparation technology, it has promoted the continuous expansion of its application fields. The introduction and combination of different materials can improve the performance of flexible composites and make them have a broader application prospect. In recent years, researchers have started preparing MXene materials as flexible composites for applications such as supercapacitors, sensors, electromagnetic shielding and thermal management. This paper gives a brief introduction to flexible composites and MXene materials, reviews the applications of MXene based flexible composites in various fields as well as the research progress, and provides an outlook on their future development direction.

Exploring highly selective polymethoxy fenamate isosteres as novel anti-prostate cancer agents: Synthesis, biological activity, molecular docking, molecular dynamics, and ADME studies

In this study, we synthesized and characterized sixteen new polymethoxy-substituted hydrazone derivatives. These compounds were evaluated for their in vitro cytotoxic activity against human prostate cancer (PC3) and human umbilical vein endothelial (HUVEC) cell lines. Compounds 5, 6, 7, and 11 exhibited significant cytotoxic effects with high selectivity index. Molecular docking studies and MM-GBSA binding free energy calculations were performed against tubulin protein. Compound 7 emerged as a particularly promising candidate, displaying an IC50 value of 1.49 µM against PC3 cells and a selectivity index of 264. Compound 7 achieved impressive docking score -13.655 kcal/mol against tubulin and formed stable hydrogen bonds and π-π stacking interactions with key residues in this protein. MD simulations confirmed the stability of the 7-tubulin complex. ADME analysis indicated that compound 7 has favorable absorption, solubility, and permeability properties, with minimal rule violations. The SAR analysis highlighted the significance of specific functional groups in enhancing the compound's cytotoxic and binding properties. Overall, compound 7 is identified as a leading candidate due to its exceptional cytotoxicity, high selectivity index, strong binding affinities, and favorable pharmacokinetic profile, making it a top candidate for further investigation and development as a novel anticancer agent.

Physicochemical analysis of Catonyx cuvieri (Mammalia, Xenarthra) remains from the Pleistocene of Paraguay

The fossil-diagenetic characteristics, such as mineralogical aspects present in the ribs of Catonyx cuvieri (Lund, 1839) (Mammalia, Xenarthra), were analyzed in this work. These analyzed remains come from the Risso Cave, San Lazaro's District, Concepción Department, Paraguay. The vibrational response was studied using Raman and Fourier transform infrared (FTIR) and the mineralogy and elemental compositions were examined using multiple characterizations techniques. The main functional groups belong to the mineral part of the bone, and specific functional groups were associated with organic components. The characterization indicated that material was composed of apatites and the original mineral structure was affected by partial ionic substitutions, probably due to the interaction of the fossil with the environment. A Gaussian deconvolution model (GM) was used to identify the individual overlapping bands in the regions of interest in the spectra. A diagenesis pathway for the fossil involved the inclusion of calcium carbonate on the surface of the bone due to the accumulation of moisture, which allowed the recrystallization of hydroxyapatite and the precipitation of calcite in the pores and silicates of the bone. It’s worth mentioning that this work is the first in the ground sloths C. cuvieri in South America. In addition, the material here constitutes the most complete fossil record of a member of the Pleistocene megafaunal of Paraguay.

A review of the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies

Antimicrobial resistance presents a formidable challenge to contemporary medicine, necessitating innovative therapeutic solutions. Azo dyes and their metal complexes have emerged as promising candidates due to their notable antimicrobial properties. This review comprehensively examines the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies. Through various synthetic strategies and metallation, the chemical structure of azo derivatives allows for modifications that enhance their antimicrobial efficacy, making them promising candidates for pharmaceutical development against microbial infections. The study provides a comprehensive understanding of the mechanisms of antimicrobial action, including DNA intercalation, enzyme inhibition, membrane disruption, and reactive oxygen species generation. The role of metal ions is particularly significant, enhancing structural stability, reactivity, and the ability to target microbial enzymes effectively. Chelation effects, such as reduced polarity and increased lipophilicity, facilitate the penetration of microbial cell membranes and the disruption of enzyme activity. The review highlights novel azo-metal complexes’ significant antifungal and antibacterial activities, particularly their efficacy against pathogens such as Mycobacterium tuberculosis. The importance of structure-activity relationships is detailed, showing how specific functional groups and metal ions influence antimicrobial efficacy. Additionally, their potential sensing ability to detect and identify microorganisms highlights the multifaceted role of azo dye derivatives in infection management.

Adsorption of Cobalt Ions by Activated Carbon Prepared from Agricultural Waste Residues and Treated with Magnetic Nanomaterials: A Review

General Background: The study of heavy metal adsorption is crucial for environmental protection and industrial wastewater management. Specific Background: The adsorption of cobalt ions (Co2+) by activated carbon derived from agricultural waste, enhanced with magnetic nanomaterials, has garnered significant interest due to its potential for cost-effective and efficient wastewater treatment. Knowledge Gap: Despite numerous studies, there remains a lack of comprehensive research on the specific combination of agricultural waste-derived activated carbon and magnetic nanomaterials for Co2+ adsorption. Aims: This study aims to meticulously review the existing literature on the preparation of activated carbon from agricultural residues, the enhancement of its properties with magnetic nanomaterials, and its effectiveness in Co2+ ion adsorption. Results: The review demonstrates that activated carbon with a large specific surface area and diverse functional groups significantly improves Co2+ adsorption. The incorporation of magnetic nanomaterials further enhances this efficiency due to increased surface area and magnetic properties. Novelty: This research uniquely combines agricultural waste valorization with advanced nanotechnology, presenting a sustainable and innovative approach to heavy metal adsorption. Implications: The findings underscore the dual environmental benefits of recycling agricultural waste and mitigating industrial pollution, offering a cost-effective and efficient solution for cobalt ion recovery from wastewater. This study serves as a valuable resource for researchers and engineers focusing on sustainable environmental remediation technologies. Highlights: Enhanced Adsorption: Magnetic nanomaterials boost activated carbon's efficiency. Sustainable Solution: Agricultural waste-derived activated carbon is eco-friendly and cost-effective. Comprehensive Insight: Review identifies research gaps and future directions. Keywords: cobalt ion adsorption, activated carbon, agricultural waste, magnetic nanomaterials, wastewater treatment

Integrated Cyano Groups into the Skeleton of Conjugated Polymers to Activate Molecular Oxygen for Boosting Photocatalytic H2O2 Efficiency.

Conjugated polymers (CPs) have shown promising potential in the field of hydrogen peroxide (H2O2) photosynthesis. However, a deeper understanding of the interactions between building units and specific functional groups within the molecular skeleton is necessary to elucidate the mechanisms driving H2O2 generation. Herein, a series of typical donor-acceptor (D-A) conjugated polymers (B-B, B-CN, B-DCN) were synthesized by introducing different amounts of cyano groups (-CN) into the molecular skeleton. The strong electron withdrawing properties of cyano can greatly promote the effective separation and transfer of photogenerated charges between building units, resulting in an impressive efficiency of H2O2 generation (2128.5 μmol g-1 h-1) for B-DCN, representing a 96-fold enhancement compared to B-B. More importantly, experimental results and theoretical calculations further revealed that the introduction of -CN can markedly reduce the adsorption energy (Ead) of O2, while serving as an active site to induce the conversion of crucial intermediate superoxide anions (.O2-) into singlet oxygen (1O2), achieving dual-channel H2O2 generation (O2→.O2-→H2O2, O2→.O2-→1O2→H2O2). This work provides valuable insights into the design of efficient H2O2 photosynthesis materials.

Functional Bio-Based Polymeric Hydrogels for Wastewater Treatment: From Remediation to Sensing Applications.

In recent years, many researchers have focused on designing hydrogels with specific functional groups that exhibit high affinity for various contaminants, such as heavy metals, organic pollutants, pathogens, or nutrients, or environmental parameters. Novel approaches, including cross-linking strategies and the use of nanomaterials, have been employed to enhance the structural integrity and performance of the desired hydrogels. The evolution of these hydrogels is further highlighted, with an emphasis on fine-tuning features, including water absorption capacity, environmental pollutant/factor sensing and selectivity, and recyclability. Furthermore, this review investigates the emerging topic of stimuli-responsive smart hydrogels, underscoring their potential in both sorption and detection of water pollutants. By critically assessing a wide range of studies, this review not only synthesizes existing knowledge, but also identifies advantages and limitations, and describes future research directions in the field of chemically engineered hydrogels for water purification and monitoring with a low environmental impact as an important resource for chemists and multidisciplinary researchers, leading to improvements in sustainable water management technology.

Effects of photodegradation on the composition characteristics and metal binding behavior of sediment-derived dissolved organic matter (SDOM) in nansi lake, China

Sediment-derived dissolved organic matter (SDOM) is instrumental in the cycling of nutrients and heavy metals within lakes, influencing ecological balance and contaminant distribution. Given the influence of photodegradation on the alteration and breakdown of SDOM, further understanding of this process is essential. In this research, the properties of the SDOM photodegradation process and its metal-binding reactions in Nansi Lake were analyzed using the EEM-PARAFAC and 2D-SF/FTIR-COS techniques. Our study identified three sorts of humic-like components and one protein-like component in SDOM, with the humic-like material accounting for 71.3 ± 5.19% of the fluorescence intensity (Fmax). Photodegradation altered the abundance and structure of SDOM, with a 41.6 ± 5.82% decrease in a280 and a 29.1 ± 9.31% reduction in Fmax after 7 days, notably reducing the protein-like component C4 by 54.0 ± 5.17% and the humic-like component C2 by 48.5 ± 2.54%, which led to SDOM being formed with lower molecular weight and aromaticity. After photodegradation, the LogKCu values for humic-like and protein-like substances decreased (humic-like C2: LogKCu: 1.35 ± 0.10–1.11 ± 0.15, protein-like C4: 1.49 ± 0.14–1.29 ± 0.34), yet the preferential binding sequence of protein-like materials and specific functional groups with Cu2+ such as aliphatic C-OH, amide (I) C=O and polysaccharide C-O groups remained unaltered. Our results enhance the knowledge of light-induced SDOM alterations and offer insights into SDOM-metal interactions in aquatic ecosystems.

Polymer-assisted synthesis of ternary magnetic graphene oxide nanocomposite for the adsorptive removal of Cr(VI) and Pb(II) ions

The presence of chromium [Cr(VI)] and lead [Pb(II)] ions in the water bodies have adverse effects on humans and aquatic life. Graphene oxide-based magnetic nanocomposites synthesized in the presence of chitosan (mGO/CS) or polyaniline (mGO/PA) as potential adsorbents for the removal of Cr(VI) and Pb(II) ions. The FTIR (Fourier transform infrared spectroscopy), EDX (Energy dispersive X-ray), XRD (X-ray diffraction) and SEM (Scanning electron microscopy) were employed to investigate the chemical composition, structural, elemental analysis, crystalline size and morphology of the nanocomposites. The FTIR results confirmed the synthesis of the nanocomposites by detecting peaks of specific functional groups. The average crystallite sizes of the mGO, mGO/CS, and mGO/PA nanocomposites were 17, 25, and 23 (nm), respectively, as determined by the Debye-Scherrer equation from the XRD data. Batch adsorption experiments were conducted for Pb(II) and Cr(VI) removal by varying the variables like pH, concentration of metal ions and contact time. The Box Behnken design (BBD) was used to optimize the adsorption parameters. Under the optimum conditions, mGO/CS and mGO/PA showed maximum removal percentages (%R) of 92.36 and 98.7 for Pb(II), and 85.25 and 93.08 for Cr(VI), respectively. The adsorption capacities were 110.84 and 118.44 mg/g for Pb(II), and 87.74 and 111.7 mg/g for Cr(VI) were obtained for mGO/CS and mGO/PA, respectively. The pseudo-second-order kinetic model and Langmuir isotherm fitted well to the experimental data and explain the adsorption mechanism of the nanocomposite materials for both metal ions.

Oxygen Functional Groups Regulate Cobalt‐Porphyrin Molecular Electrocatalyst for Acidic H2O2 Electrosynthesis at Industrial‐Level Current

AbstractElectrosynthesis of hydrogen peroxide (H2O2) based on proton exchange membrane (PEM) reactor represents a promising approach to industrial‐level H2O2 production, while it is hampered by the lack of high‐efficiency electrocatalysts in acidic medium. Herein, we present a strategy for the specific oxygen functional group (OFG) regulation to promote the H2O2 selectivity up to 92 % in acid on cobalt‐porphyrin molecular assembled with reduced graphene oxide. In situ X‐ray adsorption spectroscopy, in situ Raman spectroscopy and Kelvin probe force microscopy combined with theoretical calculation unravel that different OFGs exert distinctive regulation effects on the electronic structure of Co center through either remote (carboxyl and epoxy) or vicinal (hydroxyl) interaction manners, thus leading to the opposite influences on the promotion in 2e− ORR selectivity. As a consequence, the PEM electrolyzer integrated with the optimized catalyst can continuously and stably produce the high‐concentration of ca. 7 wt % pure H2O2 aqueous solution at 400 mA cm−2 over 200 h with a cell voltage as low as ca. 2.1 V, suggesting the application potential in industrial‐scale H2O2 electrosynthesis.

Oxygen Functional Groups Regulate Cobalt-Porphyrin Molecular Electrocatalyst for Acidic H2O2 Electrosynthesis at Industrial-Level Current.

Electrosynthesis of hydrogen peroxide (H2O2) based on proton exchange membrane (PEM) reactor represents a promising approach to industrial-level H2O2 production, while it is hampered by the lack of high-efficiency electrocatalysts in acidic medium. Herein, we present a strategy for the specific oxygen functional group (OFG) regulation to promote the H2O2 selectivity up to 92 % in acid on cobalt-porphyrin molecular assembled with reduced graphene oxide. In situ X-ray adsorption spectroscopy, in situ Raman spectroscopy and Kelvin probe force microscopy combined with theoretical calculation unravel that different OFGs exert distinctive regulation effects on the electronic structure of Co center through either remote (carboxyl and epoxy) or vicinal (hydroxyl) interaction manners, thus leading to the opposite influences on the promotion in 2e- ORR selectivity. As a consequence, the PEM electrolyzer integrated with the optimized catalyst can continuously and stably produce the high-concentration of ca. 7 wt % pure H2O2 aqueous solution at 400 mA cm-2 over 200 h with a cell voltage as low as ca. 2.1 V, suggesting the application potential in industrial-scale H2O2 electrosynthesis.

Toward Quantifying the Chemical Sensitivity of Nuclear Spin Surface Relaxivity in Mesoporous Media.

Low-field nuclear magnetic resonance (NMR) relaxation is a promising non-invasive technique for characterizing solid-liquid interactions within functional porous materials. However, the ability of the solid-liquid interface to enhance adsorbate relaxation rates, known as the surface relaxivity, in the case of different solvents and reagents involved in various chemical processes has yet to be evaluated in a quantitative manner. In this study, we systematically explore the surface relaxation characteristics of 10 liquid adsorbates (cyclohexane, acetone, water, and 7 alcohols, including ethylene glycol) confined within mesoporous silicas with pore sizes between 6 and 50 nm using low-field (12.7 MHz) two-dimensional 1H T1-T2 relaxation measurements. Functional-group-specific relaxation phenomena associated with the alkyl and hydroxyl groups of the confined alcohols are clearly distinguished; we report the dependence of both longitudinal (T1) and transverse (T2) relaxation rates of these 1H-bearing moieties on pore surface-to-volume ratio, facilitating the quantification and assignment of surface relaxivity values to specific functional groups within the same adsorbate molecule for the first time. We further demonstrate that alkyl group transverse surface relaxivities correlate strongly with the alkyl/hydroxyl ratio of the adsorbates assessed, providing evidence for a simple, quantitative relationship between surface relaxivity and interfacial chemistry. Overall, our observations highlight potential pitfalls in the application of NMR relaxation for the evaluation of pore size distributions using hydroxylated probe molecules, and provide motivation for the exploration of nuclear spin relaxation measurements as a route to adsorbate identity within functional porous materials.

Survivability of probiotic under simulated gastrointestinal conditions as affected by synbiotic (alginate-arabinoxylan) encapsulation

ABSTRACT The food industry is faced with a significant challenge in maintaining the viability and stability of probiotics during processing and in model food. Encapsulation technology offers a promising solution to this issue. This study was aimed to investigate the effect of Sodium Alginate (SA) and arabinoxylan (AX) composite encapsulation on the viability & stability of Lactobacillus rhamnosus GG. The AX was extracted from maize and characterized, and then the SA-AX composite was used to encapsulate the probiotics. The resulting microbeads were analyzed for their morphological, molecular, and physicochemical properties. The MAX-SA microbeads demonstrated the highest efficiency at 97.9 ± 0.6%, followed by MAX at 95 ± 1.5% and SA at 92 ± 1.4%. The FTIR spectra revealed specific functional groups in the samples. The MAX-SA and MSA matrices had a dispersed structure, while the MAX matrix had a smooth microstructure. The microcapsules had an average size ranging from 718 ± 2 mm to 734 ± 2 mm. The viability of the encapsulated probiotics was assessed under storage conditions, simulated gastrointestinal conditions, and model food. Encapsulated probiotics showed higher viability than free probiotics in simulated gastrointestinal conditions, and pineapple juice fortified with encapsulated probiotics showed a higher probiotic count. Overall, the study found that MAX-SA was the most effective in maintaining probiotic viability under stressed conditions.