ABSTRACT
The manuscript presents the synthesis of a new di-chromene Schiff base (COM-CH) by combining 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide and 4-oxo-4H-chromene-3-carbaldehyde, and its characterization using various analytical techniques. The probe COM-CH functional group contains a hard donor atom that selectively complexes with Th4+ ions. This report investigated COM-CH's sensing ability towards Th4+ chromogenic and fluorogenic methods in ACN: H2O (8:2, v/v) with Th4+ ions. The COM-CH-Th4+ complex was excited at 430 nm, resulting in a bright emission band at 475 nm with a 45 nm Stokes shift. The COM-CH probe demonstrated the highest performance at pH 4.0 to 8.0, with a sensitivity of 18.7 nM. The complex formation of COM-CH with Th4+ was investigated using NMR, FTIR spectrometry, and density functional theory calculations. The COM-CH and Th4+ are bound with 2:1 stoichiometry and an association constant of 1.92 × 108 M-2. The probe's performance enabled the analysis of monazite sand and water samples for Th4+ content. The probe successfully detected Th4+ content in Caenorhabditis elegans, marking the first Th4+ detection in animal models.
Subject(s)
Benzopyrans , Caenorhabditis elegans , Fluorescent Dyes , Schiff Bases , Animals , Schiff Bases/chemistry , Fluorescent Dyes/chemistry , Benzopyrans/chemistry , Spectrometry, Fluorescence/methods , Hydrogen-Ion Concentration , Optical Imaging/methodsABSTRACT
Systemic amyloidosis is a rare protein misfolding and deposition disorder leading to progressive organ failure. There are over 15 types of systemic amyloidosis, each caused by a different precursor protein which promotes amyloid formation and tissue deposition. Amyloidosis can be acquired or hereditary and can affect various organs, including the heart, kidneys, liver, nerves, gastrointestinal tract, lungs, muscles, skin and soft tissues. Symptoms are usually insidious and nonspecific resulting in diagnostic delay. The field of amyloidosis has seen significant improvements over the past decade in diagnostic accuracy, prognosis prediction and management. The advent of mass spectrometry-based shotgun proteomics has revolutionized amyloid typing and has led to the discovery of new amyloid types. Accurate typing of the precursor protein is of paramount importance as the type dictates a specific management approach. In this article, we review each type of systemic amyloidosis to provide the practitioner with practical tools to improve diagnosis and management of these rare disorders.
Subject(s)
Amyloidosis/diagnosis , Amyloidosis/therapy , Proteomics/methods , Amyloidosis/classification , Biomarkers/analysis , Diagnostic Imaging , Disease Progression , Humans , Mass Spectrometry , PrognosisABSTRACT
Enkephalins are small opioid peptides whose binding conformations are catalyzed by phospholipid membranes. Binding to opioid receptors is determined by the orientation of tyrosine and phenylalanine side chains. In this work, we investigate the effects of different charged phospholipid headgroups on the insertion of the tyrosine side chain into a lipid bilayer using a combination of 2D IR spectroscopy, anharmonic DFT calculations, and third order response function modeling. The insertion is probed by using the â¼1515 cm-1 tyrosine ring breathing mode, which we found exhibits rich vibrational dynamics on the picosecond timescale. These dynamics include rapid intramolecular vibrational energy redistribution (IVR), where some of the energy ends up in a dark state that shows up as an anharmonically shifted combination band. The waiting-time dependent 2D IR spectra also show an unusual line shape distortion that affects the extraction of the frequency-frequency correlation function (FFCF), which is the dynamic observable of interest that reflects the tyrosine side chain's insertion into the lipid bilayer. We proposed three models to account for this distortion: a hot-state exchange model, a local environment dependent IVR model, and a coherence transfer model. A qualitative analysis of these models suggests that the local environment dependent IVR rate best explains the line shape distortion, while the coherence transfer model best reproduced the effects on the FFCF. Even with these complex dynamics, we found that the tyrosine ring mode's FFCF is qualitatively correlated with the degree of insertion expected from the different phospholipid headgroups.
Subject(s)
Enkephalins/chemistry , Lipid Bilayers/chemistry , Phospholipids/chemistry , Spectroscopy, Fourier Transform Infrared/methods , Tyrosine/chemistry , Density Functional Theory , Molecular Conformation , Temperature , VibrationABSTRACT
Aggregation-induced emission (AIE) properties of an easy-to-prepare and structurally planar Schiff base derivative of the vitamin B6 cofactor pyridoxal (L) were investigated in DMSO-H2O mixed solvents. Compound L showed weak fluorescence (λem = 425 nm) in pure DMSO, but increasing the fraction of water in DMSO resulted in a significant fluorescence enhancement at 575 nm due to the restriction of intramolecular rotation (RIR) of L upon aggregation. SEM analyses revealed the formation of hairy micelle-like or needle-shaped self-assemblies/aggregates of L. The DFT calculations were performed to examine the tendency of L to form self-aggregates, and the results indicate the formation of several intramolecular non-covalent interactions that energetically favored the self-aggregation of L. The pH sensing study revealed that the red-emission of aggregates of L between pH 5.9 and 9.0 turned into green emission at the basic pH with the estimated pKa values of 9.39 and 10.22. Further, the aggregates of L were applied for the visualization of latent fingerprints (LFPs) over a non-porous glass slide.
Subject(s)
Pyridoxal/chemistry , Vitamin B 6/chemistry , Density Functional Theory , Dimethyl Sulfoxide/chemistry , Hydrogen-Ion Concentration , Molecular Structure , Particle Size , Schiff Bases/chemistry , Surface Properties , Water/chemistryABSTRACT
BACKGROUND: A previous analysis of 113 National Comprehensive Cancer Network® (NCCN®) recommendations reported that NCCN frequently recommends beyond Food and Drug Administration (FDA)-approved indications (44 off-label recommendations) and claimed that the evidence for these recommendations was weak. METHODS: In order to determine the strength of the evidence, we carried out an in-depth re-analysis of the 44 off-label recommendations listed in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). RESULTS: Of the 44 off-label recommendations, 14 were later approved by the FDA and/or are supported by randomized controlled trial (RCT) data. In addition, 13 recommendations were either very minor extrapolations from the FDA label (n = 8) or were actually on-label (n = 5). Of the 17 remaining extrapolations, 8 were for mechanism-based agents applied in rare cancers or subsets with few available treatment options (median response rate = 43%), 7 were based on non-RCT data showing significant efficacy (>50% response rates), and 2 were later removed from the NCCN Guidelines because newer therapies with better activity and/or safety became available. CONCLUSION: Off-label drug use is a frequent component of care for patients with cancer in the United States. Our findings indicate that when the NCCN recommends beyond the FDA-approved indications, the strength of the evidence supporting such recommendations is robust, with a significant subset of these drugs later becoming FDA approved or supported by RCT. Recommendations without RCT data are often for mechanism-based drugs with high response rates in rare cancers or subsets without effective therapies.
Subject(s)
Antineoplastic Agents/therapeutic use , Drug Approval , Evidence-Based Medicine , Neoplasms/drug therapy , Off-Label Use/standards , Patient Care Management/standards , Practice Guidelines as Topic/standards , Humans , Neoplasms/pathology , Off-Label Use/legislation & jurisprudence , Off-Label Use/statistics & numerical data , Prognosis , Randomized Controlled Trials as Topic , United States , United States Food and Drug AdministrationABSTRACT
In the present work, new visible-light-active nanosized Ag2S-ZnS loaded on cellulose (AZCE) was synthesized by a precipitation method. The AZCE composite was systematically characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, and UV-visible diffuse reflectance spectroscopy (UV-DRS). The activities of the photocatalysts were evaluated for rhodamine B dye (RhB) degradation under simulated sunlight and the amounts of the dye samples were analysed using a UV-vis spectrophotometer at λmax 554 nm. The effects of the reaction conditions such as pH, catalyst, hydrogen peroxide and dye concentration on the photodegradation rate have been investigated. The degradation profile reveals that 30 ppm of the dye could be effectively oxidized using 30 mg of the AZCE dose in the pH range 4-12 within 90 min. The oxidation of the RhB dye follows first-order kinetics and the rate constant was calculated to be 6.4 × 10-3 min-1. Various organic intermediates were identified during degradation using high performance liquid chromatography (HPLC), total organic content (TOC) and electron-spray ionization-mass spectrometry (ESI-MS). In order to determine the effectiveness of AZCE photocatalytic activity, other catalysts such as Ag2S loaded on cellulose (AZE) and ZnS loaded on cellulose (ZCE) were used as photocatalysts. The results show that photocatalytic activity follows the order AZCE > ACE > ZCE and this is due to the fact that a cellulose network is used as a catalyst carrier. The alkali pre-treated cellulose provides an activated surface hydroxyl groups to enhance the deposition efficiencies of Ag2S and ZnS and thereby a large amount of visible light can be absorbed and the photocatalytic activity is increased.
ABSTRACT
In this paper, a new Th4+ ion-selective chromogenic sensor (L) was developed by reacting 1,10-phenanthroline-2,9-dicarbohydrazide with 2-hydroxy naphthaldehyde. The sensing ability of L toward Th4+ was investigated in solution and paper strips loaded with L using spectrophotometric and colorimetric methods. The selective interaction of L was examined with various f-metal ions and other selected metal ions from s-block and d-block elements. Results show that by the colorimetric method in solution-phase dimethyl sulfoxide/H2O (7:3, v/v) and paper strip methods, the naked-eye detectable color change of L occurred from colorless solution to yellow-orange and pale yellow colour upon interacting with Th4+ and Al3+, respectively, whereas other metal ions did not interfere. The ligand L exhibits two absorbance bands at 320 and 375 nm because of ligand-to-ligand charge transfer. Upon interaction with Th4+, L undergoes red shift of both absorption bands and the formation of a new UV-vis band at 335 and 440 nm. The UV-visible spectral studies indicate the formation of a 1:1 host-guest complex between L and Th4+ with an association constant of 4.7 × 103 M-1. The limit of quantification and limit of detection of L for the analysis of Th4+ are found to be 167 and 50 nM, respectively. The visually detectable color change of L has been well integrated with a smartphone RGB color value to make it an analytical signal for real-time analysis of Th4+ with the detection limit down to 116 nM. Besides, L was applied for the analysis of Th4+ content present in various real water samples, monazite, and lantern mantle samples by spectrophotometry and RGB color values. The binding mode of L with Th4+ is investigated by 1H NMR, electrospray ionization-mass, and theoretical studies.
ABSTRACT
This communication focusses on the synthesis of red fluorescent lysozyme cocooned gold nanoclusters (Lyso-AuNCs) that have been successfully applied for the selective and specific recognition of the vitamin B6 cofactor pyridoxal-5'-phosphate (PLP). The red fluorescence of Lyso-AuNCs showed remarkable color change to yellow upon conjugation with PLP due to the formation of a Schiff base between the free -NH2 present in the lysozyme and the -CHO group of PLP. The developed PLP conjugated Lyso-AuNCs (PLP_Lyso-AuNCs) was applied for the selective turn-on recognition of Zn2+ ions in aqueous medium. The yellow fluorescence of PLP_Lyso-AuNCs exhibited significant enhancement at 475 nm in the presence of Zn2+ producing bluish-green fluorescence attributed to the complexation-induced aggregation of nanoclusters. The nanoprobe exhibits nanomolar limit of detection for Zn2+ ions (39.2 nM) and the practicality of the nanoprobe was validated in various environmental water samples and biological plasma, urine, and beetroot extract, with fairly good recovery percent. Also, the system was successfully implemented for the intracellular detection and monitoring of Zn2+ in live HeLa cells. Graphical abstract Applications of red emitting lysozyme cocooned gold nanoclusters (Lyso-AuNCs) for the selective recognition of the vitamin B6 cofactor pyridoxal-5'-phosphate (PLP) and the conjugated nano-assembly PLP_Lyso-AuNCs for turn-on detection of Zn2+ ions in various environmental and biological samples.
Subject(s)
Fluorescent Dyes/chemistry , Gold/chemistry , Metal Nanoparticles/chemistry , Muramidase/chemistry , Pyridoxal Phosphate/chemistry , Spectrometry, Fluorescence/methods , Zinc/analysis , Animals , Biomimetics/methods , Biosensing Techniques/methods , Cations, Divalent/analysis , Chickens , HeLa Cells , Humans , Limit of Detection , Models, Molecular , Optical Imaging/methods , Water/analysis , Zinc/blood , Zinc/urineABSTRACT
BACKGROUND: Data on the effect of systemic immunoglobulin light chain amyloidosis (AL amyloidosis) on thyroid function are limited. OBJECTIVE: To assess the prevalence of hypothyroidism in AL amyloidosis patients and determine its predictors. METHODS: 1142 newly diagnosed AL amyloidosis patients were grouped based on the thyroid-stimulating hormone (TSH) measurement at diagnosis: hypothyroid group (TSH above upper normal reference; >5 mIU L-1 ; n = 217, 19% of study participants) and euthyroid group (n = 925, 81%). Predictors for hypothyroidism were assessed in a binary multivariate model. Survival between groups was compared using the log-rank test and a multivariate analysis. RESULTS: Patients with hypothyroidism were older, more likely to present with renal and hepatic involvement and had a higher light chain burden compared to patients in the euthyroid group. Higher proteinuria in patients with renal involvement and lower albumin in patients with hepatic involvement were associated with hypothyroidism. In a binary logistic regression model, age ≥65 years, female sex, renal involvement, hepatic involvement, kappa light chain restriction and amiodarone use were independently associated with hypothyroidism. Ninety-three per cent of patients in the hypothyroid group with free thyroxine measurement had normal values, consistent with subclinical hypothyroidism. Patients in the hypothyroid group had a shorter survival compared to patients in the euthyroid group (4-year survival 36% vs 43%; P = 0.008), a difference that was maintained in a multivariate analysis. CONCLUSION: A significant proportion of patients with AL amyloidosis present with hypothyroidism, predominantly subclinical, which carries a survival disadvantage. Routine assessment of TSH in these patients is warranted.
Subject(s)
Amyloidosis/epidemiology , Hypothyroidism/epidemiology , Aged , Amyloidosis/mortality , Antibodies/blood , Comorbidity , Female , Hormone Replacement Therapy , Humans , Hypothyroidism/blood , Hypothyroidism/drug therapy , Hypothyroidism/etiology , Iodide Peroxidase/immunology , Kidney Diseases/epidemiology , Liver Diseases/epidemiology , Male , Middle Aged , Prevalence , Survival Analysis , Thyroid Hormones/therapeutic use , Thyrotropin/blood , Thyroxine/bloodABSTRACT
Worldwide breast cancer remains as the most common malignancy in women and the numbers who form a subgroup with dense breast parenchyma are substantial. In addition to mammography, the adjuncts used for further evaluation of dense breasts have been anatomically based modalities such as ultrasound and magnetic resonance imaging. The practice of functionally based imaging of breasts is relatively new but has undergone rapid progress over the past few years with promising results. The value of positron emission mammography is demonstrated in patients with dense breasts and mammographically occult disease.
Subject(s)
Breast/diagnostic imaging , Mammography/methods , Adult , Breast Density , Breast Neoplasms/diagnostic imaging , Female , Humans , Middle Aged , Positron-Emission TomographyABSTRACT
Biogenesis of the iron-sulfur (Fe-S) cluster is an indispensable process in living cells. In mammalian mitochondria, the initial step of the Fe-S cluster assembly process is assisted by the NFS1-ISD11 complex, which delivers sulfur to scaffold protein ISCU during Fe-S cluster synthesis. Although ISD11 is an essential protein, its cellular role in Fe-S cluster biogenesis is still not defined. Our study maps the important ISD11 amino acid residues belonging to putative helix 1 (Phe-40), helix 3 (Leu-63, Arg-68, Gln-69, Ile-72, Tyr-76), and C-terminal segment (Leu-81, Glu-84) are critical for in vivo Fe-S cluster biogenesis. Importantly, mutation of these conserved ISD11 residues into alanine leads to its compromised interaction with NFS1, resulting in reduced stability and enhanced aggregation of NFS1 in the mitochondria. Due to altered interaction with ISD11 mutants, the levels of NFS1 and Isu1 were significantly depleted, which affects Fe-S cluster biosynthesis, leading to reduced electron transport chain complex (ETC) activity and mitochondrial respiration. In humans, a clinically relevant ISD11 mutation (R68L) has been associated in the development of a mitochondrial genetic disorder, COXPD19. Our findings highlight that the ISD11 R68A/R68L mutation display reduced affinity to form a stable subcomplex with NFS1, and thereby fails to prevent NFS1 aggregation resulting in impairment of the Fe-S cluster biogenesis. The prime affected machinery is the ETC complex, which showed compromised redox properties, causing diminished mitochondrial respiration. Furthermore, the R68L ISD11 mutant displayed accumulation of mitochondrial iron and reactive oxygen species, leading to mitochondrial dysfunction, which correlates with the phenotype observed in COXPD19 patients.
Subject(s)
Carbon-Sulfur Lyases/physiology , Iron-Regulatory Proteins/physiology , Mitochondrial Diseases/physiopathology , Amino Acid Sequence , Carbon-Sulfur Lyases/chemistry , Carbon-Sulfur Lyases/metabolism , Disease Progression , HeLa Cells , Humans , Iron-Regulatory Proteins/chemistry , Iron-Regulatory Proteins/metabolism , Iron-Sulfur Proteins/metabolism , Mitochondrial Diseases/metabolism , Molecular Sequence Data , Protein Binding , Protein Stability , Sequence Homology, Amino AcidABSTRACT
Iron-sulfur (Fe-S) clusters are versatile cofactors involved in regulating multiple physiological activities, including energy generation through cellular respiration. Initially, the Fe-S clusters are assembled on a conserved scaffold protein, iron-sulfur cluster scaffold protein (ISCU), in coordination with iron and sulfur donor proteins in human mitochondria. Loss of ISCU function leads to myopathy, characterized by muscle wasting and cardiac hypertrophy. In addition to the homozygous ISCU mutation (g.7044GâC), compound heterozygous patients with severe myopathy have been identified to carry the c.149GâA missense mutation converting the glycine 50 residue to glutamate. However, the physiological defects and molecular mechanism associated with G50E mutation have not been elucidated. In this report, we uncover mechanistic insights concerning how the G50E ISCU mutation in humans leads to the development of severe ISCU myopathy, using a human cell line and yeast as the model systems. The biochemical results highlight that the G50E mutation results in compromised interaction with the sulfur donor NFS1 and the J-protein HSCB, thus impairing the rate of Fe-S cluster synthesis. As a result, electron transport chain complexes show significant reduction in their redox properties, leading to loss of cellular respiration. Furthermore, the G50E mutant mitochondria display enhancement in iron level and reactive oxygen species, thereby causing oxidative stress leading to impairment in the mitochondrial functions. Thus, our findings provide compelling evidence that the respiration defect due to impaired biogenesis of Fe-S clusters in myopathy patients leads to manifestation of complex clinical symptoms.
Subject(s)
Iron-Sulfur Proteins/genetics , Iron-Sulfur Proteins/metabolism , Mitochondrial Myopathies/genetics , Mutation, Missense , Amino Acid Sequence , Cell Respiration , Escherichia coli/metabolism , HSP70 Heat-Shock Proteins/metabolism , HeLa Cells , Heterozygote , Humans , Iron/chemistry , Membrane Potentials , Mitochondrial Myopathies/metabolism , Molecular Sequence Data , Mutagenesis , Oxidation-Reduction , Oxidative Stress , Reactive Oxygen Species/metabolism , Saccharomyces cerevisiae/metabolism , Sequence Homology, Amino Acid , Sulfur/chemistryABSTRACT
The link between Type 2 Diabetes (T2DM) and Parkinson's Disease (PD) dates back to the early 1960s, and ongoing research is exploring this association. PD is linked to dysregulation of dopaminergic pathways, neuroinflammation, decreased PPAR-γ coactivator 1-α, increased phosphoprotein enriched in diabetes, and accelerated α-Syn amyloid fibril production caused by T2DM. This study aims to comprehensively evaluate the T2DM-PD association and risk factors for PD in T2DM individuals. The study reviews existing literature using reputable sources like Scopus, ScienceDirect, and PubMed, revealing a significant association between T2DM and worsened PD symptoms. Genetic profiles of T2DM-PD individuals show similarities, and potential risk factors include insulin-resistance and dysbiosis of the gut-brain microbiome. Anti-diabetic drugs exhibit neuroprotective effects in PD, and nanoscale delivery systems like exosomes, micelles, and liposomes show promise in enhancing drug efficacy by crossing the Blood-Brain Barrier (BBB). Brain targeting for PD uses exosomes, micelles, liposomes, dendrimers, solid lipid nanoparticles, nano-sized polymers, and niosomes to improve medication and gene therapy efficacy. Surface modification of nanocarriers with bioactive compounds (such as angiopep, lactoferrin, and OX26) enhances α-Syn conjugation and BBB permeability. Natural exosomes, though limited, hold potential for investigating DM-PD pathways in clinical research. The study delves into the underlying mechanisms of T2DM and PD and explores current therapeutic approaches in the field of nano-based targeted drug delivery. Emphasis is placed on resolved and ongoing issues in understanding and managing both conditions.
ABSTRACT
In this work, we developed a fast and straightforward colorimetric and photoluminescent chemosensor probe (P1), featuring bis-thiophene-thiosemicarbazide moieties as its signaling and binding unit. This probe exhibited rapid sensitivity to Hg2+ and Cu2+ ions in a semi-aqueous medium, resulting in distinct colorimetric and photoluminescent changes. In the presence of Cu2+, P1 displayed an impressive 50-fold increase in photoluminescence (PL) at 450 nm (with excitation at 365 nm). The probe P1 formed a 1:1 complex with Hg2+ and Cu2+ ions, featuring association constant values of 4.04 × 104 M-1 and 1.25 × 103 M-1, respectively. P1 has demonstrated its efficacy in the analysis of real samples, yielding promising results. Additionally, the probe successfully visualized copper ions on a mouse fibroblast cell line (NIH3T3), highlighting its potential as an intracellular probe for copper ion detection.
Subject(s)
Colorimetry , Copper , Mercury , Semicarbazides , Thiophenes , Copper/analysis , Copper/chemistry , Animals , Mice , Thiophenes/chemistry , Semicarbazides/chemistry , Mercury/analysis , Colorimetry/methods , NIH 3T3 Cells , Fluorescent Dyes/chemistry , Fluorometry/methods , Spectrometry, Fluorescence , IonsABSTRACT
Methylcellulose, a prominent polysaccharide prevalent in the food sector, was considered to fabricate the active films with glutaraldehyde as a crosslinker and Noni (Morinda citrifolia) Leaf Extract (NLE) as an active agent. FTIR analysis confirms the intermolecular -OH bonding, and SEM micrograms demonstrate methylcellulose active films' homogeneous, dense morphologic appearance. Due to the crosslinking effect of glutaraldehyde and noni leaf extract, tensile strength (41.83 ± 0.134 MPa) and crystallinity (62.91 %) of methylcellulose films were improved. Methylcellulose active films suppress water and moisture uptake at various relative humidities. The inhibition capability against foodborne pathogens and the excellent antioxidant activity [DPPH (93.191 ± 1.384 %) and ABTS (90.523 ± 1.412 %)] of NLE incorporation suggested that food packed in methylcellulose active films were effective against pathogenic and oxidative attacks. During preservation, to ensure the apple slices' nutritional values, they are covered with physiochemically enhanced methylcellulose active films for up to 120 h. The minimum reduction in vitamin C, reducing sugar content, percentage weight loss, pH, and total phenolic content of apple slices preserved in MGN active films at room temperature suggests it is an affordable and efficient replacement to traditional single-use plastic packaging in the cut fruit industry.
Subject(s)
Antioxidants , Food Packaging , Malus , Methylcellulose , Morinda , Plant Extracts , Plant Leaves , Morinda/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Leaves/chemistry , Food Packaging/methods , Antioxidants/pharmacology , Antioxidants/chemistry , Methylcellulose/chemistry , Malus/chemistryABSTRACT
Biodegradable and sustainable food preservation materials have gained immense global importance to mitigate plastic pollution and environmental impact. Biopolymers like cellulose offer significant advantages for food preservation, including biodegradability and the ability to extend shelf life. Therefore, the present study aims to prepare gallic acid (GA) and zinc oxide nanoparticles (ZnO NPs) incorporated methylcellulose (MC) composite films by employing a solvent casting technique. The homogeneous SEM micrographs and FTIR spectra evidenced high compatibility among MC and GA/ZnO NPs. The UV barrier capacity, mechanical properties and surface hydrophobicity are remarkably enhanced by GA/ZnO NPs. However, the water vapour permeability and oxygen permeability of MGZ films were reduced by 49.19 % and 57.75 % respectively. Moreover, the MGZ films demonstrated exceptional antioxidant efficacy (â¼94.48 %) and inhibition against food-borne pathogens such as B. subtilis, S. aureus (Gram-positive), E. coli, P. aeruginosa (Gram-negative), and C. albicans fungi. Furthermore, the GA/ZnO NPs extended the shelf life of MGZ coated tomato samples up to 27 days and exhibited controlled microbial growth after the preservation study. These results support the application of MGZ films as suitable and effective coating materials for food packaging applications.
Subject(s)
Antioxidants , Food Preservation , Gallic Acid , Methylcellulose , Solanum lycopersicum , Zinc Oxide , Gallic Acid/chemistry , Zinc Oxide/chemistry , Methylcellulose/chemistry , Food Preservation/methods , Antioxidants/chemistry , Antioxidants/pharmacology , Food Packaging/methods , Permeability , Nanoparticles/chemistry , Hydrophobic and Hydrophilic InteractionsABSTRACT
The dynamics inside the organic regions of aerosol-OT (AOT)/water mixtures in the lamellar mesophase, bicontinuous cubic (BC) phase, and in an analogous molecule without the charged sulfonate headgroup are investigated by observing spectral diffusion, orientational relaxation and population relaxation using ultrafast two-dimensional infrared (2D IR) vibrational echo spectroscopy and IR pump-probe experiments on the asymmetric CO stretch of a vibrational probe, tungsten hexacarbonyl (W(CO)6). The water layer thickness between the bilayer planes in the lamellar phase was varied. For comparison, the dynamics of W(CO)6 in the normal liquid bis(2-ethylhexyl) succinate (EHS), which is analogous to AOT but has no charged sulfonate headgroup, were also studied. The 2D IR experiments measure spectral diffusion, which results from the structural evolution of the system. Spectral diffusion is quantified by the frequency-frequency correlation function (FFCF). In addition to a homogeneous component, the FFCFs are biexponential decays with fast and slow time components of â¼12.5 and â¼150 ps in the lamellar phase. Both components of the FFCF are independent of the number of water molecules per headgroup for the lamellae, but they slow somewhat in the BC phase. The dynamics in the ordered phases are in sharp contrast to the dynamics in EHS, which displays fast and slow components of the FFCF of 5 and 80 ps, respectively. As the hydration level of AOT increases, vibrational lifetime decreases, suggesting some change in the local environment of W(CO)6 with water content.
ABSTRACT
The effect of nanoparticles (NP) on chain dimensions in polymer melts has been the source of considerable theoretical and experimental controversy. We exploit our ability to ensure a spatially uniform dispersion of 13 nm silica NPs miscible in polystyrene melts, together with neutron scattering, x-ray scattering, and transmission electron microscopy, to show that there is no measurable change in the polymer size in miscible mixtures, regardless of the relative sizes of the chains and the nanoparticles, and for NP loadings as high as 32.7 vol%. Our results provide a firm basis from which to understand the properties of polymer nanocomposites.
Subject(s)
Nanocomposites/chemistry , Nanoparticles/chemistry , Polystyrenes/chemistry , Silicon Dioxide/chemistry , Microscopy, Electron, Transmission , Molecular Conformation , Neutron Diffraction , Scattering, Small Angle , X-Ray DiffractionABSTRACT
Aim: The aim is to evaluate the outcome of right subumbilical transverse incision approach for the management of complicated appendicitis in paediatric age group. Materials and Methods: This is a retrospective multi-institutional study which was conducted in the Department of Paediatric Surgery, I Q City Medical College and Hospital, Durgapur, West Bengal, India and the Department of Paediatric Surgery, Rajiv Gandhi Super Speciality Hospital/Raichur Institute of Medical Sciences, Raichur, Karnataka, India. In this study, a review of 77 paediatric patients operated for complicated appendicitis using a right subumbilical transverse incision approach was done for a period of 3 years (from December 2017 to December 2020). All patients had proven complicated appendicular pathology like appendicular perforation, appendicular abscess or complicated appendicular lumps on ultrasonography or computed tomography scan, which mandated exploration. Results: There was no mortality. Average operative time was 1 h 48 min (ranging from 58 min to 3 h 12 min). Average length of hospital stay was 9 days (ranging from 5 days to 13 days). There was no incidence of fecal fistula. Seventeen (22%) patients developed superficial surgical site infection which subsided with regular dressings. There was no incidence of wound dehiscence or burst abdomen. Five (6.5%) patients required the incision to be extended beyond the midline to the left side to deal with the pathology and to access the entire peritoneal cavity. Nine (11.6%) patients required loop ileostomies, which was fashioned on the lateral aspect of the transverse incision. Only one patient had a doubtful caecal injury which was repaired and loop ileostomy was done. Six patients (7.7%) had adhesive intestinal obstruction postoperatively, of which three required re-exploration. There was no incidence of incisional hernia or any stoma-related complications. Conclusion: Complicated appendicitis is a condition which lacks standardisation of approach for management, and is inherently associated with complications. However, with a more logical incision and intra-operative approach we can keep the complications to minimum and improve outcomes to great extent in those patients requiring surgical intervention. We have been using the subumbilical transverse incision in all sizes of patients ranging from small children to adolescents with excellent results, and we believe that the same approach can be applied even in adult patients in similar clinical scenarios.