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1.
J Biomed Sci ; 31(1): 43, 2024 Apr 22.
Article in English | MEDLINE | ID: mdl-38649998

ABSTRACT

Dengue viruses (DENV) are positive-stranded RNA viruses belonging to the Flaviviridae family. DENV is the causative agent of dengue, the most rapidly spreading viral disease transmitted by mosquitoes. Each year, millions of people contract the virus through bites from infected female mosquitoes of the Aedes species. In the majority of individuals, the infection is asymptomatic, and the immune system successfully manages to control virus replication within a few days. Symptomatic individuals may present with a mild fever (Dengue fever or DF) that may or may not progress to a more critical disease termed Dengue hemorrhagic fever (DHF) or the fatal Dengue shock syndrome (DSS). In the absence of a universally accepted prophylactic vaccine or therapeutic drug, treatment is mostly restricted to supportive measures. Similar to many other viruses that induce acute illness, DENV has developed several ways to modulate host metabolism to create an environment conducive to genome replication and the dissemination of viral progeny. To search for new therapeutic options, understanding the underlying host-virus regulatory system involved in various biological processes of the viral life cycle is essential. This review aims to summarize the complex interaction between DENV and the host cellular machinery, comprising regulatory mechanisms at various molecular levels such as epigenetic modulation of the host genome, transcription of host genes, translation of viral and host mRNAs, post-transcriptional regulation of the host transcriptome, post-translational regulation of viral proteins, and pathways involved in protein degradation.


Subject(s)
Dengue Virus , Dengue , Dengue Virus/physiology , Dengue Virus/pathogenicity , Dengue Virus/genetics , Humans , Dengue/virology , Animals , Host-Pathogen Interactions , Virus Replication
2.
RSC Adv ; 14(8): 5022-5036, 2024 Feb 07.
Article in English | MEDLINE | ID: mdl-38332782

ABSTRACT

Polyvinyl alcohol/yttrium oxide (PVA/Y2O3) nanocomposite films with five different weight ratios of PVA and Y2O3 nanoparticles (NPs) were prepared using a simple solution casting method. The prepared polymer nanocomposite (PNC) films were examined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). FTIR spectra exhibited a strong interaction between the PVA matrix and Y2O3 NPs. SEM results indicated that Y2O3 NPs were properly dispersed in the PVA matrix. The thermal stability of the PVA/Y2O3 nanocomposite films was found to be dependent on Y2O3 NP loading (wt%) in the nanocomposite films. Furthermore, chemiresistive gas sensing properties of the PVA/Y2O3 nanocomposite films were evaluated and the sensing parameters including sensing response, operating temperature, selectivity, stability, response/recovery time, and repeatability were systematically investigated based on the change in electrical resistance of the nanocomposite film in the presence of carbon dioxide (CO2) gas. The maximum sensing response (S) of 92.72% at a concentration of 100 ppm under an optimized operating temperature of 100 °C with a fast response/recovery time of ∼15/11 s towards CO2 gas detection was observed for the PVA/Y2O3 nanocomposite film with 5 wt% loading of Y2O3 NPs in the PVA matrix. The finding in this work suggest that Y2O3 NPs are sufficiently fast as a CO2 gas sensing material at a relatively low operating temperature. Moreover, the key role of the Y2O3 NPs in modulating the electrical and gas sensing properties of the PVA matrix is discussed here.

3.
iScience ; 27(2): 108920, 2024 Feb 16.
Article in English | MEDLINE | ID: mdl-38352227

ABSTRACT

Rapid industrialization and untreated industrial effluents loaded with toxic and carcinogenic contaminants, especially dyes that discharge into environmental waters, have led to a rise in water pollution, with a substantial adverse impact on marine life and humankind. Photocatalytic techniques are one of the most successful methods that help in degradation and/or removal of such contaminants. In recent years, semiconductor quantum dots are being substituted by carbon dots (CDs) as photocatalysts, due to the ease of formation, cost-effectiveness, possible sustainability and scalability, much lower toxicity, and above all its high capacity to harvest sunlight (UV, visible, and near infrared) through electron transfer that enhances the lifetime of the photogenerated charge carriers. A better understanding between the properties of the CDs and their role in photocatalytic degradation of dyes and contaminants is required for the formation of controllable structures and adjustable outcomes. The focus of this review is on CDs and its composites as photocatalysts obtained from different sustainable green as well as chemical precursors. Apart from the synthesis, characterization, and properties of the CDs, the study also highlights the effect of different parameters on the photocatalytic properties of CDs and their composites for catalytic dye degradation mechanisms in detail. Besides the present research development in the field, potential challenges and future perspectives are also presented.

4.
J Clin Exp Hepatol ; 14(3): 101322, 2024.
Article in English | MEDLINE | ID: mdl-38283703

ABSTRACT

Background: Hormonal oral contraceptive (OC) agents such as estrogen or progesterone, either as single agents or in combination, and a non-hormonal drug like ormeloxifene are used for various conditions. However, estrogen and progesterone-containing OC as well as ormeloxifene are seldom associated with hepatotoxicity. We prospectively studied the clinical, demographic, liver injury pattern, complications, and outcome of the hepatotoxicity from OC and ormeloxifene. Methods: We analyzed and compared the aforementioned characteristics among consecutive patients with OC and ormeloxifene-induced drug-induced liver injury (DILI) from two university hospitals in India. Cases fulfilling established DILI criteria and the Roussel Uclaf causality assessment method were identified and followed up until recovery/death. Results: We identified 43 (3.5%) amongst 1226 patients with DILI; 19 (44%) from estrogen and progesterone combination, 21 (49%) from progesterone monotherapy, and 3 (7%) due to ormeloxifene. Seven cases were identified from 1998 to 2014 and 36 cases from 2015 to 2023. All were due to oral tablets. The mean age was 36 years (range 21-75). Nineteen patients (44%) developed jaundice and 5 (11.6%) developed itching. The liver injury pattern was hepatocellular in 19 (44%), mixed in 13 (30%), and cholestatic in 11 (26%). Four patients (9%) died, three from acute liver failure and one due to acute on chronic liver failure. Liver biochemical tests normalized after a mean of 66 days after stopping the implicated agents. Contrastingly, literature search yielded 24 cases of progesterone DILI reported between 1962 and 2019 with no mortality. Conclusion: In contrast to published literature on oral contraceptives, a majority of oral contraceptive-induced DILI in our series were from progesterone monotherapy and a smaller number with ormeloxifene, that often resulted in clinically significant jaundice or liver test abnormalities and rarely in fatality.

5.
Proteins ; 92(2): 179-191, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37789571

ABSTRACT

The cation-aromatic database (CAD) is a comprehensive repository of cation-aromatic motifs found in experimentally determined protein structures, first reported in 2007 [Proteins, 2007, 67, 1179]. The present article is an update of CAD that contains information of approximately 27.26 million cation-aromatic motifs. CAD uses three distance parameters (r, d1, and d2) to determine the position of the cation relative to the centroid of the aromatic residue and classifies the motifs as cation-π or cation-σ interactions. As of June 2023, about 193 936 protein structures were retrieved from Protein Data Bank, and this resulted in the identification of an impressive number of 27 255 817 cation-aromatic motifs. Among these motifs, spherical motifs constituted 94.09%, while cylindrical motifs made up the remaining 5.91%. When considering the interaction of metal ions with aromatic residues, 965 564 motifs are identified. Remarkably, 82.08% of these motifs involved the binding of metal ions to the amino acid HIS. Moreover, the analysis of binding preferences between cations and aromatic residues revealed that the HIS-HIS, PHE-ARG, and TRP-ARG pairs exhibited a preferential geometry. The motif pair HIS-HIS was the most prevalent, accounting for 19.87% of the total, closely followed by TYR-LYS at 10.17%. Conversely, the motif pair TRP-HIS had the lowest occurrence, representing only 4.20% of the total. The data generated help in revealing the characteristics and biological functions of cation-aromatic interactions in biological molecules. The updated version of CAD (Cation-Aromatic Database V2.0) can be accessed at https://acds.neist.res.in/cadv2.


Subject(s)
Amino Acids , Proteins , Amino Acids/chemistry , Cations/chemistry , Metals
6.
Int J Biol Macromol ; 253(Pt 5): 127207, 2023 Dec 31.
Article in English | MEDLINE | ID: mdl-37797858

ABSTRACT

The Aromatic-Aromatic Interactions Database (A2ID) is a comprehensive repository dedicated to documenting aromatic-aromatic (π-π) networks observed in experimentally determined protein structures. The first version of A2ID was reported in 2011 [Int J Biol Macromol, 2011, 48, 540]. It has undergone a series of significant updates, leading to its current version, which focuses on the identification and analysis of 3,444,619 π-π networks from proteins. The geometrical parameters such as centroid-centroid distances (r) and interplanar angles (ϕ) were used to identify and characterize π-π networks. It was observed that among the 84,500 proteins with at least one aromatic π-π network, about 92.50 % of the instances are found to be either 2π (77.34 %) or 3π (15.23 %) networks. The analysis of interacting amino acid pairs in 2π networks indicated a dominance of PHE residues followed by TYR. The updated version of A2ID incorporates analysis of π-π networks based on SCOP2 and ECOD classifiers, in addition to the existing SCOP, CATH, and EC classifications. This expanded scope allows researchers to explore the characteristics and functional implications of π-π networks in protein structures from multiple perspectives. The current version of A2ID along with its extensive dataset and detailed geometric information is publicly accessible using https://acds.neist.res.in/a2idv2.


Subject(s)
Amino Acids , Proteins , Protein Conformation , Proteins/chemistry
7.
Rev Med Virol ; 33(6): e2481, 2023 11.
Article in English | MEDLINE | ID: mdl-37758688

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) emerged in December 2019, causing a range of respiratory infections from mild to severe. This resulted in the ongoing global COVID-19 pandemic, which has had a significant impact on public health. The World Health Organization declared COVID-19 as a global pandemic in March 2020. Viruses are intracellular pathogens that rely on the host's machinery to establish a successful infection. They exploit the gene expression machinery of host cells to facilitate their own replication. Gaining a better understanding of gene expression modulation in SARS-CoV2 is crucial for designing and developing effective antiviral strategies. Efforts are currently underway to understand the molecular-level interaction between the host and the pathogen. In this review, we describe how SARS-CoV2 infection modulates gene expression by interfering with cellular processes, including transcription, post-transcription, translation, post-translation, epigenetic modifications as well as processing and degradation pathways. Additionally, we emphasise the therapeutic implications of these findings in the development of new therapies to treat SARS-CoV2 infection.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Pandemics , RNA, Viral
8.
J Mech Behav Biomed Mater ; 145: 106005, 2023 09.
Article in English | MEDLINE | ID: mdl-37423011

ABSTRACT

The orthotic insole is a device that is placed between the bottom of the foot and the sole of the shoe. It bears the body weight and directly influences the biomechanics of the foot and the body. These insoles are used to minimize the stress by reducing plantar pressure between support points hence minimizing the pressure. Such customized insoles have usually been produced by either handmade or subtractive methods. Fused deposition modeling (FDM) has opened innovative ways for the manufacture of orthotic insoles. In recent studies, no specific computer-aided design (CAD) tools are available to design and manufacture the insole, which is the primary focus. This work aims to evaluate established CAD techniques for designing and fabricating insoles utilizing different manufacturing processes. The evaluation is based on a prior analysis of the possibilities for functionalizing insole materials and structures. In this study, multiple software tools are utilized for designing custom insoles, considering pressure points and a three-dimensional (3D) foot scan of an individual. The research highlights how the implementation of software enables a significant level of customization by integrating pressure mapping data into the insole design process. A novel CAD approach for designing an orthotic insole has been provided in this work. Soft poly-lactic acid (PLA) is used to fabricate an insole using FDM technology. The gyroid and solid samples were evaluated following ASTM standards. When compared to the solid construction, the gyroid structure has a high specific energy absorption capability, which is used to create the orthotic insole. The results of the experiment suggest that the selection of the structure for customized insole design is significantly affected by the infill density parameter.


Subject(s)
Foot Orthoses , Pressure , Equipment Design , Foot , Printing, Three-Dimensional , Walking
9.
Heliyon ; 9(4): e15416, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37151638

ABSTRACT

Melanoma is an abnormal proliferation of skin cells that arises and develops in most of the cases on surface of skin that is exposed to copious amounts of sunlight. This common type of cancer may develop in areas of the skin that are not exposed to a much abundant sunlight. The research addresses the problem of Segmentation and Classification of Melanoma Skin Cancer. Melanoma is the fifth most common skin cancer lesion. Bio-medical Imaging and Analysis has become more promising, interesting, and beneficial in recent years to address the eventual problems of Melanoma Skin Cancerous Tissues that may develop on Skin Surfaces. The evolved research finds that Attributes Selected for Classification with Color Layout Filter model. The research has produced an optimal result in terms of certain performance metrics accuracy, precision, recall, PRC (what is PRC? Expansion is needed in Abstract), The proposed method has yielded 90.96% of accuracy and 91% percent of precise and 0.91 of recall out of 1.0, 0.95 of ROC AUC, 0.87 of Kappa Statistic, 0.91 of F-Measure. It has been noticed a lowest error with reference to proposed method on certain dataset. Finally, this research recommends that the Attribute Selected Classifier by implementing one of the image enhancement techniques like Color Layout Filter is showing an efficient outcome.

10.
Int J Emerg Med ; 16(1): 20, 2023 Mar 17.
Article in English | MEDLINE | ID: mdl-36932335

ABSTRACT

BACKGROUND: The new zoonotic viral infection, monkeypox, is a global health issue. Our study aimed at studying the epidemiology, clinical presentation, complications, case fatality rate, and transmission among the present cases of monkeypox infection. METHODS: Articles were searched in PubMed, Google Scholar, and Science Direct databases using the keywords "Monkeypox" [MeSH] or "Monkeypox virus" (MeSH). Narrative reviews, conference abstracts, commentaries, and articles in languages other than English were excluded. RESULTS: From three databases, 1442 studies were identified. Seven hundred ten articles were excluded because they included data before 2022, leaving 732 items for screening. After filtering 320 data due to data duplication, 412 remained. Due to the inclusion of systematic reviews, meta-analyses, reviews, comments, and articles in languages other than English, 257 were excluded. Eligibility based on full-text review was applied to the remaining 155, excluding 129. So, the study covered a total of remaining 26 articles. We studied 2352 confirmed cases from published literature, accounting for approximately 4% of infected cases worldwide. Around 81.71% of patients have a bisexual or men having sex with men (MSM) preference. Approximately 30.18% of confirmed cases were HIV positive. Male sex was also identified as a risk factor in our review. CONCLUSION: Monkeypox human-to-human and human-to-animal transmission are rising. Thus, it is essential to do research on the prevention, clinicodemographic trends, and treatment of monkeypox. Understanding this will enable us to treat monkeypox patients with a targeted and focused approach.

11.
Sci Rep ; 13(1): 4021, 2023 Mar 10.
Article in English | MEDLINE | ID: mdl-36899067

ABSTRACT

In this study we analyzed the flow, heat and mass transfer behavior of Casson nanofluid past an exponentially stretching surface under the impact of activation energy, Hall current, thermal radiation, heat source/sink, Brownian motion and thermophoresis. Transverse magnetic field with the assumption of small Reynolds number is implemented vertically. The governing partial nonlinear differential equations of the flow, heat and mass transfer are transformed into ordinary differential equations by using similarity transformation and solved numerically by using Matlab bvp4c package. The impact of each of the Hall current parameter, thermal radiation parameter, heat source/sink parameter, Brownian motion parameter, Prandtl number, thermophoresis parameter and magnetic parameter on velocity, concentration and temperature, is discussed through graphs. The skin friction coefficient along the x-and z-directions, the local Nusselt number and the Sherwood number are calculated numerically to look into the inside behavior of the emerging parameters. It is witnessed that the flow velocity is a diminishing function of the thermal radiation parameter and the behavior has observed in the case of Hall parameter. Moreover, mounting values of Brownian motion parameter reduce the nanoparticle concentration profile.

12.
Drug Discov Today ; 28(2): 103463, 2023 02.
Article in English | MEDLINE | ID: mdl-36481584

ABSTRACT

Long-acting injectable (LAI) delivery technologies have enabled the development of several pharmaceutical products that improve patient health by delivering therapeutics from weeks to months. Over the last decade, due to its good biocompatibility, formulation tunability, wide range of degradation rates, and extensive clinical studies, polyester-based LAI technologies including poly(lactic-co-glycolic acid) (PLGA) have made substantial progress. Herein, we discuss PLGA properties with seminal approaches in the development of LAIs, the role of molecular dynamic simulations of polymer-drug interactions, and their effects on quality attributes. We also outline the landscape of various advanced PLGA-based and a few non-PLGA LAI technologies; their design, delivery, and challenges from laboratory scale to preclinical and clinical use; and commercial products incorporating the importance of end-user preferences.


Subject(s)
Molecular Dynamics Simulation , Polyesters , Humans , Polylactic Acid-Polyglycolic Acid Copolymer , Polymers , Pharmaceutical Preparations
13.
Org Biomol Chem ; 20(46): 9117-9121, 2022 11 30.
Article in English | MEDLINE | ID: mdl-36367090

ABSTRACT

Rhodium catalyzed alkyne-tethered intramolecular annulation has been demonstrated for the synthesis of tetracyclic carbazole skeletons and a series of five to eight-membered pyrido[3,2,1-jk]carbazoles were successfully obtained. The present atom economical annulation proceeded under mild reaction conditions, offering a broad substrate scope.


Subject(s)
Rhodium , Rhodium/chemistry , Catalysis , Alkynes/chemistry , Carbazoles/chemistry
14.
RSC Adv ; 12(41): 26712-26726, 2022 Sep 16.
Article in English | MEDLINE | ID: mdl-36275157

ABSTRACT

Dilute magnetic oxide semiconductors doped with transition metals have attracted significant attention both theoretically and experimentally due to their interesting and debatable magnetic behavior. In this work, we investigated the influence of Fe, Co and Ni doping on the structural, optical and magnetic properties of SnO2 nanoparticles, which were produced via a simple sol-gel technique. Raman spectroscopy, XRD, XPS, TEM, FT-IR characterizations were performed to study the crystal structure and morphology of the pure and doped nanoparticles, which confirmed the tetragonal rutile structure of the SnO2 nanoparticles. The XPS analysis revealed the incorporation of divalent dopant ions in the host matrix. The Raman plots indicated the generation of the cassiterite crystal structure, structural disorder and oxygen vacancies in the pure and doped SnO2 nanoparticles. The UV-visible plots indicated a decrease in the bandgap for the doped SnO2 nanoparticles because doping introduced defect levels in the band gap. The photoluminescence study showed the creation of oxygen vacancies due to the doping of different charge states of dopants. The magnetic study based on varying the temperature and field of magnetization revealed the diamagnetic nature of SnO2 at 300 K and 5 K respectively, and the concurrence of ferromagnetic (FM) and paramagnetic (PM) nature in doped SnO2 nanoparticles. The bound polaron model was used to explain the co-existence of FM and PM behavior in all the doped SnO2 nanoparticles.

15.
Med J Armed Forces India ; 78(Suppl 1): S179-S185, 2022 Sep.
Article in English | MEDLINE | ID: mdl-36147423

ABSTRACT

Background: Studies among type 2 diabetes mellitus patients have reported total caries experience; however the severity and clinical consequences of untreated dental caries are often ignored. Methods: For this study, 150 well (I) and poorly controlled (II) diabetic participants were recruited. The spectrum of caries was evaluated using DMFT (Decayed, Missing and Filled Tooth) index, Dental Caries Severity Classification Scale, PUFA (Pulpal involvement, Ulceration, Fistula and Abscess) index, RCI (Root Caries Index) and the severity of radicular caries by Root Surface Caries Severity Index. Results: The prevalence of coronal and root caries was 90.7% and 23.3%, respectively. There was significant difference among caries experiences for D, M and DMFT. In group II, severity of coronal caries and mean rank of P, F, A and PUFA scores were higher, so were prevalence of root caries and severity of RD2, RD3 and RD4. HbA1c level had positive correlation with DMFT and PUFA scores (r = 0.458 and 0.522), so was the duration of diabetes with coronal caries, DMFT, PUFA score, root caries and RCI score (r = 0.235, 0.320, 0.273, 0.308 and 0.323). Conclusion: This is probably the first study to examine the severity of coronal caries, prevalence of untreated dental caries and severity of radicular caries in diabetic patients. Uncontrolled diabetes causes substantial increase in prevalence and severity of coronal and radicular caries.

16.
J Assoc Physicians India ; 70(3): 11-12, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35438293

ABSTRACT

AIM: To address the existing gaps in knowledge about long-acting nitroglycerine (LA-NTG) and provide recommendations to address these issues. METHODOLOGY: Approved LA-NTG questionnaire that included 17 questions related to the role of LA-NTG in the management of angina and chronic coronary syndrome (CCS) was shared with 150 expert cardiologists from different regions from India. Results of these survey questionnaires were further discussed in 12 regional level meetings. The opinions and suggestions from all the meetings were compiled and analyzed. Further, recommendations were made with the help of attending national cardiology experts and a consensus statement was derived. RESULTS: This is the first consensus on LA-NTG, summarizing the clinical evidence from India and suggesting recommendations based on these data. The experts recommended early use of LA-NTG as a first-line antianginal therapy in combination with beta-blocker since it improves exercise tolerance in patients with CCS. A strong consensus was observed for using LA-NTG in patients with co-morbid hypertension, diabetes, chronic kidney disease and post-percutaneous coronary intervention angina. As a part of cardiac rehabilitation, LA-NTG allows patients with angina to exercise to a greater functional capacity. CONCLUSIONS: A national consensus was observed for several aspects of LA-NTG in the management of angina and CCS. The clinical experience of the experts confirmed an extremely satisfied patient perception about the efficacy of LA-NTG.


Subject(s)
Cardiovascular Agents , Percutaneous Coronary Intervention , Angina Pectoris/drug therapy , Cardiovascular Agents/therapeutic use , Humans , India , Nitroglycerin/therapeutic use , Syndrome
17.
Clin Adv Periodontics ; 12(2): 75-79, 2022 06.
Article in English | MEDLINE | ID: mdl-33216473

ABSTRACT

INTRODUCTION: The increasing esthetic demands from patients have required that clinicians sharpen their skills and adopt newer and more novel techniques to satisfy these demands. In periodontal therapy, periodontal plastic surgery poses a substantial challenge to the clinician, both because it is technique sensitive and also because it includes a wide array of procedures and their variations. Conventional plastic procedures have provided satisfactory results in the treatment of gingival recession but there is, presently, a greater need for more advanced procedures that cause less surgical morbidity as also provide improved results. Minimally invasive surgery has been harnessed in periodontics for this purpose and has been extensively used in multiple indications, including root coverage. Modified-Vestibular Incision Supra-periosteal Tunnel Access (M-VISTA) applies the principles of minimally invasive surgery to provide satisfactory results in root coverage. CASE PRESENTATION: A 28-year-old male patient presented with multiple Miller Class I/II buccal recession defects and associated high labial frenum on right maxillary anterior teeth. M-VISTA technique allowed coronal repositioning of gingival margin, which was then stabilized by orthodontics bracket assisted suturing technique. The V-shaped incision in the region of the frenal attachment allowed for conducting both the M-VISTA and frenectomy techniques simultaneously. Connective tissue graft was inserted in the supra-periosteal tunnel and vertical incision was sutured. Complete root coverage was achieved and maintained at 9 months with excellent esthetic outcomes. CONCLUSIONS: The use of connective tissue graft along with M-VISTA technique allows the clinician to successfully treat multiple recession defects.


Subject(s)
Gingival Recession , Adult , Connective Tissue/transplantation , Esthetics, Dental , Gingiva/transplantation , Gingival Recession/surgery , Humans , Male , Surgical Flaps , Tooth Root/surgery , Treatment Outcome
18.
Environ Res ; 203: 111842, 2022 01.
Article in English | MEDLINE | ID: mdl-34363804

ABSTRACT

Nickel oxide (NiO) nanoparticles (NPs) and graphene quantum dots (GQDs) reinforced polyvinyl alcohol (PVA) nanocomposite films were prepared using a solution casting technique. The physicochemical characteristics of PVA/NiO/GQDs (PNG) nanocomposite films were studied using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM). The obtained PNG nanocomposite films showed good mechanical flexibility and improved tensile strength. The influence of nanofiller concentrations on PNG nanocomposite film. The obtained results demonstrate an increase in the activation energy (Ea) up to PNG3 upon increasing the GQDs concentration and thereafter, its decreases. The fundamental interactions of the constituents of PNG nanocomposite film were investigated using density functional theory (DFT). This study on electronic structure reveals that the PVA model indirectly interacts with GQDs through the NiO model. This configuration is favoured in terms of interaction energy (-78 kJ/mol) compared to the one in which PVA interacts directly with the GQDs model.


Subject(s)
Graphite , Nanocomposites , Nanoparticles , Quantum Dots , Nickel , Polyvinyl Alcohol , Spectroscopy, Fourier Transform Infrared
19.
Environ Res ; 204(Pt C): 112297, 2022 03.
Article in English | MEDLINE | ID: mdl-34740623

ABSTRACT

PVDF-HFP/BaTiO3/GQDs polymer nanocomposite films with good flexibility and high dielectric constant (ϵ) at low frequency were prepared via solution casting technique. Different compositions of BaTiO3 (non-conducting ceramic nanofiller) and Graphene quantum dots (GQDs) (conducting nanofiller) utilized as co-filler were embedded in poly (vinylidene fluoride-co-hexafluoroethylene) (PVDF-HFP) polymer matrix. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) techniques were employed to characterize the prepared nanocomposite films. The mechanical properties of PVDF-HFP/BaTiO3/GQDs nanocomposite films were also investigated. Dielectric properties of nanocomposite films such as dielectric constant (ϵ), dielectric loss (tanδ) and AC conductivity ( σac ) were also determined as a function of frequency and temperature. Highest ϵ with relatively low tanδ obtained at low frequency for maximum temperature in all polymer nanocomposite films. The σac increases from lower (100 Hz) to higher frequency up to 100 kHz and drops to zero for the further increment of frequency. These results suggest that the PVDF-HFP/BaTiO3/GQDs nanocomposites are the most promising materials for energy storage applications.


Subject(s)
Graphite , Nanocomposites , Nanoparticles , Quantum Dots , Barium , Graphite/chemistry , Nanocomposites/chemistry , Quantum Dots/chemistry
20.
Front Chem ; 9: 738852, 2021.
Article in English | MEDLINE | ID: mdl-34733820

ABSTRACT

An exhaustive study of Sc-ion interaction with water molecules in all its possible oxidation and spin states has been carried out to delineate the relative propensity of Sc ions toward solvation and water splitting. Potential energy surface analysis of the Sc-ion reaction with water molecules, topological analysis of bonds, and the effect of sequential solvation up to 6 water molecules have been examined. Calculated values showed good agreement with the available experimental results. Close-shell systems such as singlet mono- and tricationic Sc ions prefer to split the water molecules. In contrast, the open-shell systems such as triplet mono- and doublet dicationic Sc ions prefer to get solvated than split the water molecule. Topological analysis of electron density predicted the Sc+/2+-water bond as a noncovalent bond while Sc3+-OH2, Sc2+-OH, and Sc+-H bonds as partially covalent in nature. Energy decomposition analysis revealed that Sc ion-water interactions are driven by electrostatic energy followed by polarization energy. The current study reveals that transition metal catalysis can be one of the most effective tools to employ in water splitting, by properly tuning the electrons, spin, and ligands around the catalytic center.

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