Browsing by Author "Shweta"

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A dichloro-substituted salicylimine as a bright yellow emissive probe for Al3+
(Elsevier B.V., 2016) Neeraj; Ajit Kumar; Sharad Kumar Asthana; Shweta; K.K. Upadhyay
A salicylimine based Al3+ specific fluorescent turn on probe (SB-1) was designed, characterized and evaluated through various spectroscopic techniques. The 1:1 chemical interaction between SB-1 and Al3+ takes place through O—N—O donor sites leading to chelation enhanced fluorescence (CHEF). The lowest detection limit for this measurement was found to be 7.69 × 10−9 M. The binding interaction of SB-1 with Al3+ was studied through 1H & 13C NMR studies, IR as well as through DFT calculations. The HeLa live cells were found to be permeable enough for SB-1 and was able to detect Al3+ inside the cells through confocal microscope. © 2016 Elsevier B.V.
A highly sensitive naphthaoxazole-based cell-permeable ratiometric chemodosimeter for hydrazine
(Royal Society of Chemistry, 2016) Shweta; Ajit Kumar; Neeraj; Sharad Kumar Asthana; Anand Prakash; Jagat Kumar Roy; Ida Tiwari; K.K. Upadhyay
The environmental toxicity, detonable characteristics and widespread usage of hydrazine in industrial activities, coupled with the fact that it is a leading candidate as a hydrogen reservoir, mean that selective methods for the detection of trace levels of hydrazine are much needed. We report herein a ratiometric chemodosimeter (P1) for the highly efficient detection of hydrazine at a lowest level of 1.79 × 10-9 M. The P1 probe was designed by the judicious anchoring of a naphthaoxazole skeleton to malononitrile. The same chemodosimeter also enables the bioimaging of hydrazine in live cells. The performance of P1 was tested in the form of test paper strips, as well as in the solid state for the identification of hydrazine vapours. The sensing mechanism was established through spectroscopic techniques and was further fortified through theoretical calculations using density functional theory. © 2016 The Royal Society of Chemistry.
A novel nanocomposite of HAp-TiC-Ag with enhanced mechanical and biological properties for bone regrowth and anticancer applications
(Royal Society of Chemistry, 2025) Sarvesh Kumar Avinashi; Shweta; Rajat Kumar Mishra; Saurabh Kumar; Amreen Shamsad; Shama Parveen; Surajita Sahu; Savita Kumari; Zaireen Fatima; Vijay Pratap; Rupesh Kumar; Monisha Banerjee; Monalisa Mishra; Horesh Kumar; Rakesh Kumar C. Gautam; Chandkiram Gautam
Hydroxyapatite (HAp)-based composites are extensively used in various applications, including bone regeneration, bone implants, catalysis, drug delivery, and cancer treatment, owing to their unique properties such as osteogenesis, osteoconduction, and osteoinduction, as well as their ability to inhibit tumor cell growth. In this study, pure HAp and silver (Ag) nanoparticles were synthesized using microwave irradiation and green synthesis methods, while a solid-state reaction route was employed for the fabrication of HAp-TiC-Ag composites aimed at enhancing their mechanical and biological properties. A range of characterization techniques, including XRD, FTIR, Raman, XPS, DLS, SEM, TEM, and in vitro assays, were used to assess the structural, morphological, mechanical, and biological properties of the composites. The composite HTA6 exhibited excellent mechanical properties, including a high compressive strength (185 MPa), elevated fracture toughness (10.88 MPa m1/2), a moderate Young's modulus (1.08 GPa), and a Vickers hardness (339.65 HV). The cell viability tests demonstrated that HTA6 treatment did not significantly reduce osteoblast cell growth, while significantly inhibiting the proliferation of cancer cells. Additionally, the composite showed good biocompatibility, displaying non-cytotoxicity in D. melanogaster and strong antibacterial activities against the tested bacteria. These findings suggest that HTA6 is a promising candidate for applications in bone regeneration and cancer treatment. © 2025 The Royal Society of Chemistry.
A smart ratiometric red fluorescent chemodosimeter for fluoride based on anthraquinone nosylate
(Royal Society of Chemistry, 2017) Shweta; Ajit Kumar; Neeraj; Sharad Kumar Asthana; K.K. Upadhyay
The present work reports a smart design of a chemodosimeter, namely 4-(6,11-dihydro-6,11-dioxo-1H-anthra[1,2-d]imidazol-2-yl)phenyl-4-nitrobenzenesulfonate (AH), which recognises F- specifically through a naked eye colour change from light yellow to light orange and remarkable ratiometric fluorescence from green to red from the matrix of a large number of similar anions in acetonitrile solution. The sensing mechanism was worked out as fluoride-triggered deprotonation of imidazole accompanied by deprotection of nosylate group (p-nitrobenzenesulfonate group). AH was fully characterized through single crystal X-ray diffraction studies along with FT-IR, 1H and 13C NMR and ESI-MS. The detection limit calculated through fluorescent titration was found to be 3.45 × 10-10 M. Theoretical calculations at density functional level were in agreement with experimental observations. AH also showed its practical applicability in the form of test paper strips. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
An overview on manufactured nanoparticles in plants: Uptake, translocation, accumulation and phytotoxicity
(Elsevier Masson SAS, 2017) Durgesh Kumar Tripathi; Shweta; Shweta Singh; Swati Singh; Rishikesh Pandey; Vijay Pratap Singh; Nilesh C. Sharma; Sheo Mohan Prasad; Nawal Kishore Dubey; Devendra Kumar Chauhan
The unprecedented capability to control and characterize materials on the nanometer scale has led to the rapid expansion of nanostructured materials. The expansion of nanotechnology, resulting into myriads of consumer and industrial products, causes a concern among the scientific community regarding risk associated with the release of nanomaterials in the environment. Bioavailability of excess nanomaterials ultimately threatens ecosystem and human health. Over the past few years, the field of nanotoxicology dealing with adverse effects and the probable risk associated with particulate structures <100 nm in size has emerged from the recognized understanding of toxic effects of fibrous and non-fibrous particles and their interactions with plants. The present review summarizes uptake, translocation and accumulation of nanomaterials and their recognized ways of phytotoxicity on morpho-anatomical, physiological, biochemical and molecular traits of plants. Besides this, the present review also examines the intrinsic detoxification mechanisms in plants in light of nanomaterial accumulation within plant cells or parts. © 2016 Elsevier Masson SAS
Application of CRISPR-cas technique in enhancing the phytochemicals production
(Bentham Science Publishers, 2024) Harshita Sahoo; Manisha Malhotra; Vikas Kumar Yadav; Vikash Maurya; Shweta; Akhilesh Kumar
Plants possess a remarkable skill in the generation of secondary metabolites, which are commonly referred to as phytochemicals. These bioactive molecules are non-nutritive and essential for the growth and expansion of plants. However, these phytochemicals play a critical role in plant resistance against both biotic and abiotic stress. Furthermore, they possess a vast array of pharmaceutical and nutraceutical properties, making them commercially and economically significant. Unfortunately, the synthesis of these compounds is not abundant and can be challenging to extract through a cumbersome chemically synthetic process that is both inefficient and expensive. Fortunately, second-generation CRISPR/Cas technology has proven to be a gateway to enhancing the production of phytochemicals due to its simplicity, efficiency, and target specificity. Therefore, the purpose of this chapter is to discuss the mechanistic role of CRISPR/Cas9, its application in base editing, and its ability to enhance the production of phytochemicals. © 2024 Bentham Science Publishers. All rights reserved.
Availability and Risk Assessment of Nanoparticles in Living Systems: A Virtue or a Peril?
(Elsevier Inc., 2018) Shweta; Durgesh K. Tripathi; Devendra Kumar Chauhan; Jose R. Peralta-Videa
Interaction of nanoparticles with living systems on earth has been occurring since ancient times, but as the technology increases each day, application of natural and anthropogenic nanoparticles also increases, which disturbs our ecosystem. Nanoparticles have a devastating effect on the environment by affecting directly or indirectly microbes, plants, and humans. In the era of increasing industrialization, nanoparticles have many advantages, but also many inevitable disadvantages. Their applications are so vast that they have become a part of our daily lives, for example, they are used in cosmetics, drugs, agriculture, electronics, etc.; however, when they are released in the environment, they cause deleterious effects. Thus to secure the environment, governments have devised a number of risk assessment and remediation plans to placate these effects on living organisms. In spite of this, scientists are trying to alter their role by increasing the quality of products to enhance the quality and quantity of crops by either supplying nanoparticles to the plants directly or by genetically modifying them. In this chapter, we have tried to summarize the positive and negative impacts of nanoparticles on living systems: plants, humans, and microorganisms. © 2018 Elsevier Inc. All rights reserved.
Brightening Quinolineimines by Al3+ and Subsequent Quenching by PPi/PA in Aqueous Medium: Synthesis, Crystal Structures, Binding Behavior, Theoretical and Cell Imaging Studies
(American Chemical Society, 2017) Sharad Kumar Asthana; Ajit Kumar; Neeraj; Shweta; Sumit Kumar Hira; Partha Pratim Manna; K.K. Upadhyay
Recent years have witnessed an upsurge of Al3+ selective optical sensors involving simple Schiff bases to other complex organic frameworks. However, more than ∼95% of such reports lack crystallographic evidence, and proposals of binding sites for Al3+ are based upon spectroscopic evidence only. We herein synthesized and fully characterized a quinolineimine derivative (CMO) and explored its potential toward efficient detection of Al3+ with crystallographic evidence. The ongoing nonradiative photoinduced electron transfer (PET) and excited state intramolecular proton transfer (ESIPT) processes in CMO got inhibited via the chelation enhanced fluorescence (CHEF) effects induced by Al3+, and consequently turn-on fluorescence response was observed with 18-fold emission enhancements. The theoretical calculations performed were in good consonance with experimental results. We also explored further the applicability of the CMO·Al3+ complex toward highly sensitive and selective detection of inorganic phosphate (PPi) and an explosive picric acid (PA) via fluorescence quenching processes through two different chemical routes. The bioimaging of Al3+ and PPi were carried out in the living human cancer cells (MCF-7). © 2017 American Chemical Society.
Design-specific mechanistic regulation of the sensing phenomena of two Schiff bases towards Al3+
(Royal Society of Chemistry, 2016) Shweta; Neeraj; Sharad Kumar Asthana; Rakesh K. Mishra; K.K. Upadhyay
We report herein two optical probes (R1 and R2) for the fluorogenic detection of Al3+ at the level of 10-8 M. R1 and R2 were synthesized by simple Schiff base condensation of 4-amino-3-hydroxy-1-naphthalene sulfonic acid with 5-bromosalicaldehyde and 2-hydroxy-1-naphthaldehyde, respectively. The same were characterized by various spectroscopic techniques. R1 and R2 both underwent fluorescence emission upon their respective interactions with Al3+ in an ethanol:water mixture (4:1, v/v). The binding modes of the receptors with Al3+ were studied through 1H NMR spectroscopy, Job plots, and HR-MS, as well as through binding constant determination involving fluorescence titration data. The quenching of -CN isomerization and of photoinduced electron transfer (PET) seem to be responsible for the fluorogenic switch-on situation of R1 and R2 with Al3+. At the same time, excited state intramolecular proton transfer (ESIPT) also plays an important role in the ratiometric fluorescence response of R2, which is a consequence of a minor structural variation in R1 where the bromophenyl moiety is replaced with a naphthalene moiety. The mechanistic aspects of the sensing phenomenon are discussed in terms of 1H NMR titration as well as theoretical calculations at the density functional level. © 2016 The Royal Society of Chemistry.
Doping impacts of La2O3 on physical, structural, optical and radiation shielding properties of (30-x)BaCO3-30TiO2-40SiO2-xLa2O3 (0 ≤ x ≤ 6) glasses for optoelectronic applications
(Institute of Physics, 2023) Rajat Kumar Mishra; Savita Kumari; Shweta; Prince Sen; Sarvesh Kumar Avinashi; Zaireen Fatima; Harel Thomas; Manasi Ghosh; Krishna Kishor Dey; Chandkiram Gautam
Herein, synthesis of novel barium silicate glasses doped with La2O3 in the system (30-x)BaCO3-30TiO2-40SiO2-xLa2O3, BTSL (0 ≤ x ≤ 6) via fast melt-quenching technique was carried out. Further, to confirm the amorphous behaviour of prepared glass samples, x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were carried out. The density of all prepared glasses was determined using Archimedes’ principle and found to be in an increasing manner. To investigate the doping influence of La2O3 on the glasses, few more physical properties like molar volume (Vm), polaron radius (rp), and field strength (Fs) were also studied and found to be increased due to incorporation of La2O3 into BTSL glassy system. Moreover, to explore the structural, functional, and bonding mechanism of the glasses, FTIR, Raman and 29Si-MAS-ssNMR spectroscopies were performed. Further, to investigate the numerous optical parameters, UV-visible spectroscopy was executed, and energy band gaps were found in the decreasing manner as increasing the La2O3 concentrations. Additionally, to study the optoelectronic properties, refractive indices (η) and optical dielectric constant (ϵ) were determined and revealed the increasing behaviour and found suitable material for optoelectronic devices. Furthermore, the radiation shielding parameters, mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), etc were determined using Phy-X/PSD software and these parameters are increased owing to the doping of La2O3. Among all fabricated glasses, (30-x)BaCO3-30TiO2−40SiO2−6La2O3, BTS6L glass exhibited outstanding optical and radiation attenuation properties; can be tailored for the fabrication of optoelectronic and radiation protection devices. © 2023 IOP Publishing Ltd.
Drosophila glial system: an approach towards understanding molecular complexity of neurodegenerative diseases
(Springer Science and Business Media B.V., 2024) Shweta; Khushboo Sharma; Mallikarjun Shakarad; Namita Agrawal; Shashank Kumar Maurya
Glia is pivotal in regulating neuronal stem cell proliferation, functioning, and nervous system homeostasis, significantly influencing neuronal health and disorders. Dysfunction in glial activity is a key factor in the development and progression of brain pathology. However, a deeper understanding of the intricate nature of glial cells and their diverse role in neurological disorders is still required. To this end, we conducted data mining to retrieve literature from PubMed and Google Scholar using the keywords: glia, Drosophila, neurodegeneration, and mammals. The retrieved literature was manually screened and used to comprehensively understand and present the different glial types in Drosophila, i.e., perineurial, subperineurial, cortex, astrocyte-like and ensheathing glia, their relevance with mammalian counterparts, mainly microglia and astrocytes, and their potential to reveal complex neuron-glial molecular networks in managing neurodegenerative processes. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.
Efficient visualization of H2S via a fluorescent probe with three electrophilic centres
(Royal Society of Chemistry, 2016) Sharad Kumar Asthana; Ajit Kumar; Neeraj; Shweta; K.K. Upadhyay
H2S is a reactive nucleophilic species with toxic effects towards human beings. Its efficient detection and marking is still a challenging job due to its similar nucleophilic character to a number of biothiols, like glutathione, cysteine, homocysteine etc. We report herein the first ever use of a chemosensor incorporating three electrophilic centres to achieve high sensitivity and very fast response time (40 s) towards H2S. © The Royal Society of Chemistry 2016.
Evolution of shock waves in dusty nonideal gas flow with magnetic field
(Walter de Gruyter GmbH, 2024) Shweta; Pradeep; Shobhit Kumar Srivastava; Lal Pratap Singh
This paper deals with the study of propagation of shock waves in 2-D steady supersonic magnetogasdynamics flow of nonideal dusty gas using wavefront analysis method. We derived the transport equation, which determines the condition for the shock formation. Our aim is to analyze the effect of interaction of dust particles with magnetic field in nonideal gas on the evolution of shock formation and to examine how the flow patterns of the disturbance vary with respect to the variations in the physical parameters of the medium. It is found that the presence of magnetic field plays an essential role in the wave propagation phenomena. The nature of the solution with respect to the Mach number is analyzed, and it is examined how the shock formation distance changes with an increase or decrease in the value of Mach number. Also, the combined effect of nonidealness, magnetic field, and dust particles on the shock formation distance is elucidated and examined how the formation of shocks is affected by the increase in the value of corresponding physical parameters. © 2024 Walter de Gruyter GmbH, Berlin/Boston.
Evolution of weak discontinuity waves in non-ideal interstellar environments
(Springer, 2023) Shweta; Rahul Kumar Chaturvedi; Shobhit Kumar Srivastava; L.P. Singh
A systematic method is used to study the problem of propagation of planar, cylindrically symmetric and spherically symmetric shock waves of the one-dimensional motion of an inviscid, self-gravitating, non-ideal interstellar gas cloud. The analytic solution of the problem is resolved, which specifies non-linear behavior in the physical plane. The transport equation, which describes the evolution of weak discontinuity in non-ideal gas is derived. It is observed that the nature of the solution completely depends on the net volumetric cooling rate and self-gravitating parameter. It is observed that an increase in the value of self-gravitating parameter results in delay of process of shock formation and shock forms early when heating dominates cooling in the system. Also, expansive waves take less time to decay in planar geometry as compared to cylindrical and spherical geometries and compressive waves take more time to develop shocks for cylindrical and spherical geometries as compared to planar geometry. © 2023, Indian Academy of Sciences.
Fabrication of bioactive transparent glass ceramics 55SiO2–25Na2O-(15-x)CaO–5P2O5- xZrO2 (0≤x≤6): Physical, structural and in vitro cell viability insights for biomedical applications
(Elsevier Ltd, 2024) Shweta; Rajat Kumar Mishra; Bijay Laxmi Pradhan; Shama Parveen; Priyatama Behera; Sarvesh Kumar Avinashi; Savita Kumari; Zaireen Fatima; Prince Sen; Saurabh Kumar; Monalisa Mishra; Monisha Banerjee; Krishna Kishor Dey; Manasi Ghosh; Chandkiram Gautam
Zirconia (ZrO2) reinforced transparent glass ceramics (TGCs) are excellent materials for enhanced cell viability and biocompatibility for biomedical applications. Herein, ZrO2 doped SiO2–Na2O–CaO–P2O5 base compositions derived from traditional melt-quench technique. The impacts of ZrO2 on the physical, structural, optical, morphological, and biological evaluation were studied. XRD discloses the major phase formation of buchwaldite (CaNaPO4) and disodium calcium silicate (Na2CaSiO4). Density of the TGC samples was calculated and found to be in the range of 2.535–2.910 g/cm3. The optical parameters, and particle size were estimated and analyzed. Herein, ZrO2 plays a significant role as a network modifier and various bond assignments in the glassy network that confirmed by FTIR spectroscopy. Surface morphology and its elemental investigations were also studied using SEM and XPS techniques. Solid state NMR spectrum on 23Na, 29Si, and 31P nucleus were studied for various interactions. Moreover, the cell viability of the fabricated samples on the cancer cells were analyzed and resulted to possess the half maximum inhibitory concentrations (IC50) of the samples were calculated and valued to be 92 to 40 μg/ml respectively. The sample 55SiO2–25Na2O–9CaO–5P2O5–6ZrO2 (BG4) demonstrated a remarkable biological activity for bone regeneration and implants. Further, the cell cytotoxicity was evaluated by performing trypan blue assay, DAPI and DCFH-DA staining on the TGC samples. The data assembled in this research approves the hypothesis that the TGCs represent a feasible material for the biomedical applications for bone and tooth implants. © 2024 Elsevier Ltd and Techna Group S.r.l.
Influence of carbon nanotubes reinforcement on the structural feature and bioactivity of SiO2–Al2O3–MgO–K2CO3–CaO–MgF2 bioglass
(Springer Science and Business Media Deutschland GmbH, 2021) Shweta; Chandkiram Gautam; Krishna Kishor Dey; Manasi Ghosh; Ravi Prakash; Kriti Sharma; Divya Singh
Various glass compositions were synthesized using a melt-quenching technique doped with different concentrations of carbon nanotubes (CNTs) from 0.1 to 0.7% in the glassy system SiO2–Al2O3–MgO–K2CO3–CaO–MgF2. Density was determined by employing a liquid displacement method. Several physical parameters such as molar volume (Vm), oxygen molar volume (Vo) were calculated and found to be decreases from 36.49 ± 0.729 to 24.28 ± 0.485 × 10–6 m3/mol, and 21.86 ± 0.437 to 14.60 ± 0.292 × 10–6 m3/mol, respectively. However, density and oxygen packing density (OPD) increases from 1.99 ± 0.099 to 2.98 ± 0.149 × 103 kg/m3 and 45.74 ± 0.914 to 68.49 ± 1.369 × 10–3 kg-atom/l with increasing content of CNT. In the present study, reinforcement effects of CNTs were explained using several spectroscopic techniques like Fourier transform infrared, ultraviolet–visible (UV–Vis), Raman, and nuclear magnetic resonance (NMR) spectroscopy, respectively. Based on Tauc plots of the UV–Vis spectra, the energy band gap was determined and their values decreased from 6.95 to 6.23 × 10–19 J which is owing to the formation of non-bridging oxygen (NBO) in the glassy matrix. Contact angle measurements were also performed to check the wettability of the glasses and their values increased with CNT % from 18.14° to 77.8°. 29Si-MAS-NMR spectroscopic study revealed the random distribution of two different cations, Ca 2 + and Mg 2 + within the glasses which lead to structural and topological frustration. To check the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and alkaline phosphatase assay were also performed. Owing to outstanding stability in various fluids like saline water, distilled water, and hydrochloric acid, the fabricated glasses exhibited functional activities with an adequate proliferation of rat calverail osteoblast cells. Consequently, based on the various characterization techniques such as mechanical, tribological, and biological activities, the fabricated bioactive glasses can be used for biomedical and multifunctional applications. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
Lignocellulolytic enzymes: Potential biocatalysts to pre-treat lignocellulosic biomass for its biotechnological and industrial applications
(Nova Science Publishers, Inc., 2024) Manisha Malhotra; Karishma Mittal; Vikas Kumar Yadav; Vikash Maurya; Shweta; Akhilesh Kumar
Lignocellulosic biomass, otherwise considered waste from agricultural and forest areas, has found its potential application in various sectors such as biomedical, cosmeceutical, pharmaceutical sectors, etc. Moreover, they can be utilized to produce bioplastic and can be used as a sustainable alternative for energy production. However, the lignin content present in the lignocellulosic biomass poses a hindrance in its complete utilization. Therefore, to delignify the lignocellulosic biomass, traditionally, various physical and chemical pre-treatment methods have been introduced, which again are not only expensive but also prove to be hazardous for the environment as the chemical treatment of the lignocellulosic biomass may result in harmful end products. Hence, to eliminate these problems, research has now been focused on utilizing biological methods to delignify and detoxify the lignocellulosic biomass which includes various lignocellulosic enzymes such as laccase, lignin peroxidase, manganese peroxidase, and versatile peroxidase for its pretreatment. This chapter, therefore, aims to summarize the introduction of various lignocellulosic enzymes and their potential role in the pretreatment of the lignocellulosic biomass, in order to make the biomass applicable for various biotechnological and industrial applications as well as for the production of bioethanol. © 2024 Nova Science Publishers, Inc. All rights reserved.
Metabolomics quantitative trait loci mapping of medicinal plants and crops
(Bentham Science Publishers, 2024) Pratiksha Verma; Vikash Maurya; Vikas Kumar Yadav; Manisha Malhotra; Shweta; Akhilesh Kumar
Genetic association studies and quantitative trait loci (QTL) analysis serve as indispensable tools for identifying genes and genomic regions associated with various traits. The rapid development of genomics and its application in plant breeding has profoundly impacted the field, fostering discoveries and revolutionizing breeding strategies. For a better understanding of plant physiology, complete information on biochemical pathways is imperative across different organizational levels, encompassing simple to intricate networks that regulate trait expression. Over the past decades, the emergence of metabolomics as a vital branch of "omics" has played a pivotal role in determining and quantifying metabolites governing cellular processes. The combination of metabolomics and post-genomic approaches has recently allowed proficient examination of genetic and phenotypic associations in cultivated crops. A novel and powerful methodology, Metabolomic Quantitative Trait Locus (mQTL) mapping, has emerged as an approach to unravel the genetic components and loci contributing to the variability in metabolic profiles. This chapter provides an in-depth exploration of mQTL mapping in both medicinal and crop plants, elucidating its significance in unraveling the intricate interplay between genetics and metabolic pathways. © 2024 Bentham Science Publishers. All rights reserved.
Physical, Structural, and Optical Properties of ZrO2 Reinforced (100-x–y)[SrTiO3]-x[2B2O3.SiO2]-y[ZrO2] Glasses
(Springer Science and Business Media B.V., 2023) Rajat Kumar Mishra; Shweta; Prince Sen; Krishna Kishor Dey; Manasi Ghosh; Chandkiram Gautam
Several attempts were made to fabricate zirconia (ZrO2) reinforced strontium titanate (SrTiO3) borosilicate glasses in the system (100-x–y)[SrTiO3]-x[2B2O3.SiO2]-y[ZrO2] (38 ≤ x ≤ 39, 0 ≤ y ≤ 4 by mole %) via a rapid melt-quenching method. To check the amorphous behaviour of the prepared glasses, XRD measurements were performed. Further, density of the bulk transparent glasses was evaluated by liquid-displacement method (Archimedes’ principle) and found to be in the range of 2.6068–3.0720 gcm−3. To study the effect of ZrO2 doping on the fabricated glasses, various physical parameters such as oxygen molar volume (Omv), molar volume (Vm), oxygen packing density (OPD), ion-concentrations (N), etc. were determined. Further, to investigate the molecular structure, and bonding information, FTIR spectroscopy was performed. Additionally, to determine the various optical properties, the UV–visible spectroscopy was also performed, and with the help of Davis-Mott plots, increasing optical band gap energies were obtained in the range of 4.29—4.78 eV. Besides these parameters, an optical dielectric constant (ε), and average refractive index (η) were determined which lies within the increasing range of 120.0374–207.3341 and 1.9269–2.0690 respectively. Moreover, to elaborate the structure of the fabricated glasses, 29Si and 11B MAS SSNMR spectra were recorded which shows the formation of silicate networks which became highly polymerized with increasing concentrations of ZrO2. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.
Plants and carbon nanotubes (CNTs) interface: Present status and future prospects
(Springer Singapore, 2017) Shweta; Kanchan Vishwakarma; Shivesh Sharma; Raghvendra Pratap Narayan; Prateek Srivastava; Ambrina Sardar Khan; Nawal Kishore Dubey; Durgesh Kumar Tripathi; Devendra Kumar Chauhan
The unique characteristics of nanomaterials utilizing carbon have drawn great attention and interest since the breakthrough of fullerenes (in 1985), carbon nanotubes (CNTs, in 1991), and graphene (in 2004). This discovery has led to the promotion of developing methods in order to produce it at large industrial scales. Engineered nanomaterials are continuously finding its applications in medical sector, technical devices, environmental purposes, as well as agricultural sector. Despite its wide applications, there is also the unintended release of carbon- based nanostructures into the environment, thereby affecting or posing inimical effect toward the living systems like plants. The researchers are trying to engineer such nanoparticles in a way that it may impose some advanced and beneficial applications in living systems. One of the engineered carbon-based nanomaterials includes carbon nanotubes (CNTs) which can be further classified as single-walled carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), water-soluble multiwalled carbon nanotubes, functionalized singlewalled carbon nanotubes, double-walled carbon nanotubes etc. This chapter, therefore, focuses on all aforementioned types of carbon nanotubes, techniques utilized in synthesis, and current status of research with respect to the impact of carbon nanotubes on plant growth and development addressing relevant knowledge gap. © 2017, Springer Nature Singapore Pte Ltd.