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1.
J Biol Chem ; 300(9): 107619, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39098530

ABSTRACT

Alzheimer's disease (AD) poses an immense challenge in healthcare, lacking effective therapies. This study investigates the potential of anthranilamide derivative (AAD23), a selective M2 receptor antagonist, in proactively preventing cognitive impairments and cholinergic neuronal degeneration in G protein-coupled receptor kinase-5-deficient Swedish APP (GAP) mice. GAP mice manifest cognitive deficits by 7 months and develop senile plaques by 9 months. A 6-month AAD23 treatment was initiated at 5 months and stopped at 11 months before behavioral assessments without the treatment. AAD23-treated mice exhibited preserved cognitive abilities and improved cholinergic axonal health in the nucleus basalis of Meynert akin to wildtype mice. Conversely, vehicle-treated GAP mice displayed memory deficits and pronounced cholinergic axonal swellings in the nucleus basalis of Meynert. Notably, AAD23 treatment did not alter senile plaques and microgliosis. These findings highlight AAD23's efficacy in forestalling AD-related cognitive decline in G protein-coupled receptor kinase-5-deficient subjects, attributing its success to restoring cholinergic neuronal integrity and resilience, enhancing resistance against diverse degenerative insults.


Subject(s)
Alzheimer Disease , Cholinergic Neurons , Cognitive Dysfunction , G-Protein-Coupled Receptor Kinase 5 , Mice, Transgenic , Animals , Mice , Cognitive Dysfunction/drug therapy , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Cholinergic Neurons/metabolism , Cholinergic Neurons/drug effects , Cholinergic Neurons/pathology , G-Protein-Coupled Receptor Kinase 5/metabolism , G-Protein-Coupled Receptor Kinase 5/genetics , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/genetics , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Male , Humans
2.
J Org Chem ; 89(18): 13167-13178, 2024 Sep 20.
Article in English | MEDLINE | ID: mdl-39258458

ABSTRACT

Until now, a myriad of effective approaches have emerged for the functionalization of N-heteroaryl C-H bonds. In contrast, dearomatization and construction of fused heterocycles from activated heteroarenes is still a subject to explore. In this work, we present a refined approach for both dearomatization of N-heteroarenes and the synthesis of fused heterocycles from activated heteroarenes ruthenium catalysis using paraformaldehyde along with additive and base. Notably, quinolinium salts with a hydrogen at the C-4 position yield a methoxymethyl-substituted fused cyclic product through the Thorpe Ingold effect. An innovative aspect of this research is the dual functionality of paraformaldehyde as both a hydride donor and electrophile, utilizing readily available feedstock chemicals. A broad range of electron withdrawing and donating substituents was tolerable under standardized reaction conditions.

3.
Environ Res ; 261: 119661, 2024 Nov 15.
Article in English | MEDLINE | ID: mdl-39043353

ABSTRACT

Ruminants release enteric methane into the atmosphere, significantly increasing greenhouse gas emissions and degrading the environment. A common focus of traditional mitigation efforts is on dietary management and manipulation, which may have limits in sustainability and efficacy, exploring the potential of essential microorganisms as a novel way to reduce intestinal methane emissions in ruminants; a topic that has garnered increased attention in recent years. Fermentation and feed digestion are significantly aided by essential microbes found in the rumen, such as bacteria, fungi, and archaea. The practical implications of the findings reported in various studies conducted on rumen gut concerning methane emissions may pave the way to understanding the mechanisms of CH4 production in the rumen to enhance cattle feed efficiency and mitigate CH4 emissions from livestock. This review discussed using essential bacteria to reduce intestinal methane emissions in ruminants. It investigates how particular microbial strains or consortia can alter rumen fermentation pathways to lower methane output while preserving the health and productivity of animals. We also describe the role of probiotics and prebiotics in managing methane emissions using microbial feed additives. Further, recent studies involving microbial interventions have been discussed. The use of new methods involving functional metagenomics and meta-transcriptomics for exploring the rumen microbiome structure has been highlighted. This review also emphasizes the challenges faced in altering the gut microbiome and future directions in this area.


Subject(s)
Gastrointestinal Microbiome , Methane , Ruminants , Methane/metabolism , Animals , Ruminants/microbiology , Rumen/microbiology , Rumen/metabolism , Greenhouse Gases/metabolism , Probiotics , Cattle , Fermentation , Bacteria/metabolism
4.
Sensors (Basel) ; 24(14)2024 Jul 09.
Article in English | MEDLINE | ID: mdl-39065825

ABSTRACT

In this paper, we present the design of a millimeter-wave 1 × 4 linear MIMO array antenna that operates across multiple resonance frequency bands: 26.28-27.36 GHz, 27.94-28.62 GHz, 32.33-33.08 GHz, and 37.59-39.47 GHz, for mm-wave wearable biomedical telemetry application. The antenna is printed on a flexible substrate with dimensions of 11.0 × 44.0 mm2. Each MIMO antenna element features a modified slot-loaded triangular patch, incorporating 'cross'-shaped slots in the ground plane to improve impedance matching. The MIMO antenna demonstrates peak gains of 6.12, 8.06, 5.58, and 8.58 dBi at the four resonance frequencies, along with a total radiation efficiency exceeding 75%. The proposed antenna demonstrates excellent diversity metrics, with an ECC < 0.02, DG > 9.97 dB, and CCL below 0.31 bits/sec/Hz, indicating high performance for mm-wave applications. To verify its properties under flexible conditions, a bending analysis was conducted, showing stable S-parameter results with deformation radii of 40 mm (Rx) and 25 mm (Ry). SAR values for the MIMO antenna are calculated at 28.0/38.0 GHz. The average SAR values for 1 gm/10 gm of tissues at 28.0 GHz are found to be 0.0125/0.0079 W/Kg, whereas, at 38.0 GHz, average SAR values are 0.0189/0.0094 W/Kg, respectively. Additionally, to demonstrate the telemetry range of biomedical applications, a link budget analysis at both 28.0 GHz and 38.0 GHz frequencies indicated strong signal strength of 33.69 dB up to 70 m. The fabricated linear MIMO antenna effectively covers the mm-wave 5G spectrum and is suitable for wearable and biomedical applications due to its flexible characteristics.


Subject(s)
Telemetry , Wearable Electronic Devices , Telemetry/instrumentation , Telemetry/methods , Humans , Wireless Technology/instrumentation , Equipment Design
5.
World J Microbiol Biotechnol ; 40(3): 82, 2024 Jan 29.
Article in English | MEDLINE | ID: mdl-38285311

ABSTRACT

Dunaliella salina is a favourable source of high lipid feedstock for biofuel and medicinal chemicals. Low biomass output from microalgae is a significant barrier to industrial-scale commercialisation. The current study aimed to determine how photosynthetic efficiency, carbon fixation, macromolecular synthesis, accumulation of neutral lipids, and antioxidative defence (ROS scavenging enzyme activities) of D. salina cells were affected by different light intensities (LI) (50, 100, 200, and 400 µmol m-2 s-1). The cells when exposed to strong light (400 µmol m-2 s-1) led to reduction in chlorophyll a but the carotenoid content increased by 19% in comparison to the control (LI 100). The amount of carbohydrate changed significantly under high light and in spite of stress inflicted on the cells by high irradiation, a considerable increase in activity of carbonic anhydrase and fixation rate of CO2 were recorded, thus, preserving the biomass content. The high light exposed biomass when subjected to nitrogen-deficient medium led to increase in lipid content (59.92% of the dry cell weight). However, neutral lipid made up 78.26% of the total lipid while other lipids like phospholipid and glycolipid content decreased, showing that the lipid was redistributed in these cells under nitrogen deprivation, making the organism more appropriate for biodiesel/jet fuel use. Although D. salina cells had a relatively longer generation time (3.5 d) than other microalgal cells, an economic analysis concluded that the amount of carotenoid they produced and the quality of their lipids made them more suited for commercialization.


Subject(s)
Biofuels , Microalgae , Chlorophyll A , Carbon , Carotenoids , Glycolipids , Nitrogen
6.
Int Ophthalmol ; 44(1): 394, 2024 Sep 25.
Article in English | MEDLINE | ID: mdl-39320616

ABSTRACT

PURPOSE: To evaluate the difference in ganglion cell layer (GCL) thickness on optical coherence tomography (OCT) and waveform on pattern electroretinography (PERG) among glaucoma suspects and healthy controls. METHODS: An analytical, cross-sectional study was done on 100 eyes of 50 subjects, equally divided in the glaucoma suspect and control group. Subjects with an asymmetrically increased vertical cup-to-disc ratio and without any perimetric change were taken as suspects, and subjects with normal findings were taken as controls. GCL thickness was evaluated on spectral domain OCT at 3 mm, 3.45 mm, and 6 mm centering the foveola, and P50, N95 wave forms were recorded according to the standard PERG protocol. RESULTS: In this study, we observed that the average GCL thickness is significantly less in glaucoma suspects at 3.45 mm (p = 0.045) and at 6 mm (p < 0.001) circle zone. On PERG, P50 amplitude was significantly low in glaucoma suspects in comparison to controls (p = 0.007). There was significantly increased implicit time for both P50 and N95 in glaucoma suspects (p < 0.001). For N95 amplitude, a non-significant (p = 0.127) difference was observed among the two groups. At 3.45 mm, average GCL thickness showed a weak negative correlation with N95 implicit time (r = - 0.286, p = 0.044), a weak positive correlation with P50 amplitude (r = 0.349, p = 0.013), and at 6 mm, a weak positive correlation with P50 amplitude (r = 0.311, p = 0.028) in glaucoma suspects. CONCLUSIONS: Analysing GCL thickness can help in the structural assessment of preperimetric glaucoma. PERG can be used as a valuable tool for the detection of ganglion cell dysfunction, even before cell loss.


Subject(s)
Electroretinography , Intraocular Pressure , Ocular Hypertension , Retinal Ganglion Cells , Tomography, Optical Coherence , Humans , Retinal Ganglion Cells/pathology , Cross-Sectional Studies , Male , Female , Tomography, Optical Coherence/methods , Electroretinography/methods , Middle Aged , Intraocular Pressure/physiology , Ocular Hypertension/physiopathology , Ocular Hypertension/diagnosis , Nerve Fibers/pathology , Visual Fields/physiology , Adult , Glaucoma/physiopathology , Glaucoma/diagnosis , Optic Disk/pathology , Optic Disk/diagnostic imaging , Aged
7.
Phys Chem Chem Phys ; 25(47): 32503-32514, 2023 Dec 06.
Article in English | MEDLINE | ID: mdl-37997153

ABSTRACT

Metal-organic framework (MOF) based proton conductors are synthesized by the Avrami model (time-temperature modalities). Our objective here is to obtain a material with high proton conductivity in anhydrous conditions, improved catalytic behaviour and morphology control of conductivity, band gap and catalysis. For this purpose, we try to understand the role of morphology on mass transportation using computational fluid dynamics and the experimental realisation using the synthesis of MOF membranes with high protonic conductivity. In order to alter the morphology, the membranes are synthesized from protic ionic liquid (dimethyl ethyl amine H2PO4) and metal ion (Co3O4) at different temperatures and duration. A high protonic conductivity of 0.0286 S cm-1 with a high transference number >0.99 is observed in anhydrous conditions with the change in morphology. Furthermore, catalyst properties along with high activity (Tafel slope = 39 mV decade-1) with the alteration in morphology are also investigated in detail and observed adsorption governed conduction. This adsorption governed conduction is verified using computational fluid dynamics simulations with the alteration in morphology. This study suggests that morphology not only plays a pivotal role in obtaining a robust proton exchange membrane, it also improves the catalytic functionality and stability of the membrane.

8.
Curr Microbiol ; 81(1): 22, 2023 Nov 28.
Article in English | MEDLINE | ID: mdl-38017305

ABSTRACT

Microbial community exhibit shift in composition in response to temperature variation. We report crude oil-degrading activity and high-throughput 16S rRNA gene sequencing (metagenome) profiles of four bacterial consortia enriched at three different temperatures in crude oil-amended Bushnell-Hass Medium from an oily sludge sediment. The consortia were referred to as O (4 ± 2 â„ƒ in 3% w/v crude oil), A (25 ± 2 â„ƒ in 1% w/v crude oil), H (25 ± 2 â„ƒ in 3% w/v crude oil), and X (45 ± 2 â„ƒ in 3% w/v crude oil). The hydrocarbon-degrading activity was highest for consortium A and H and lowest for consortium O. The metagenome profile revealed the predominance of Proteobacteria (62.12-1.25%) in each consortium, followed by Bacteroidota (18.94-37.77%) in the consortium O, A, and H. Contrarily, consortium X comprised 7.38% Actinomycetota, which was essentially low (< 0.09%) in other consortia, and only 0.41% Bacteroidota. The PICRUSt-based functional analysis predicted major functions associated with the metabolism and 5060 common KEGG Orthology (KOs). A total of 296 KOs were predicted exclusively in consortium X. Additionally, 247 KOs were predicted from xenobiotic biodegradation pathways. This study found that temperature had a stronger influence on the composition and function of the bacterial community than crude oil concentration.


Subject(s)
Microbial Consortia , Petroleum , Temperature , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/metabolism , Microbial Consortia/genetics , Hydrocarbons/metabolism , Bacteria/genetics , Bacteria/metabolism , Biodegradation, Environmental , Petroleum/metabolism , Bacteroidetes/genetics
9.
Phys Chem Chem Phys ; 24(9): 5330-5342, 2022 Mar 02.
Article in English | MEDLINE | ID: mdl-35188501

ABSTRACT

Herein, the influence of compositional engineering via active site alternation on catalytic behaviour has been studied for the Ruddlesden-Popper-based system Sm2-xSrxNiO4-δ. A phase change from orthorhombic (x = 0.6) to tetragonal (x = 1.0) in bulk Sm2-xSrxNiO4-δ is confirmed by Rietveld (XRD) analysis, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). To alter the active sites, we fabricated thin films for x = 0.6 and x = 1.0 using a pulsed laser deposition technique. The electrocatalytic behaviour has been studied in an environmentally friendly medium, i.e., a neutral medium (pH = 7), for both bulk and thin films, and parameters such as transient response, electrochemical reversibility and oxygen evolution reactivity are measured. The cyclic voltammetry curves suggest that electrochemical reversibility for thin films is governed by adsorption as opposed to the diffusion observed for bulk samples. Our investigation further suggests that moderate electroactivity can be achieved with an increase in active sites on miniaturization with the phase change.

10.
Sensors (Basel) ; 22(20)2022 Oct 14.
Article in English | MEDLINE | ID: mdl-36298163

ABSTRACT

The excessive use of digital platforms with rapidly increasing users in the wireless domain enforces communication systems to provide information with high data rates, high reliability and strong transmission connection quality. Wireless systems with single antenna elements are not able to accomplish the desired needs. Therefore, multiple-input multiple-output (MIMO) antennas are getting more attention in modern high-speed communication systems and play an essential part in the current generation of wireless technology. However, along with their ability to significantly increase channel capacity, it is a challenge to achieve an optimal isolation in a compact size for fifth-generation (5G) terminals. Portable devices, automobiles, handheld gadgets, smart phones, wireless sensors, radio frequency identification and other applications use MIMO antenna systems. In this review paper, the fundamentals of MIMO antennas, the performance parameters of MIMO antennas, and different design approaches and methodologies are discussed to realize the three most commonly used MIMO antennas, i.e., ultra-wideband (UWB), dual-band and circularly polarized antennas. The recent MIMO antenna design approaches with UWB, dual band and circularly polarized characteristics are compared in terms of their isolation techniques, gain, efficiency, envelope correlation coefficient (ECC) and channel capacity loss (CCL). This paper is very helpful to design suitable MIMO antennas applicable in UWB systems, satellite communication systems, GSM, Bluetooth, WiMAX, WLAN and many more. The issues with MIMO antenna systems in the indoor environment along with possible solutions to improve their performance are discussed. The paper also focuses on the applications of MIMO characteristics for future sixth-generation (6G) technology.


Subject(s)
Wireless Technology , Reproducibility of Results , Equipment Design
11.
Int J Mol Sci ; 23(20)2022 Oct 11.
Article in English | MEDLINE | ID: mdl-36292920

ABSTRACT

Vegetable crops possess a prominent nutri-metabolite pool that not only contributes to the crop performance in the fields, but also offers nutritional security for humans. In the pursuit of identifying, quantifying and functionally characterizing the cellular metabolome pool, biomolecule separation technologies, data acquisition platforms, chemical libraries, bioinformatics tools, databases and visualization techniques have come to play significant role. High-throughput metabolomics unravels structurally diverse nutrition-rich metabolites and their entangled interactions in vegetable plants. It has helped to link identified phytometabolites with unique phenotypic traits, nutri-functional characters, defense mechanisms and crop productivity. In this study, we explore mining diverse metabolites, localizing cellular metabolic pathways, classifying functional biomolecules and establishing linkages between metabolic fluxes and genomic regulations, using comprehensive metabolomics deciphers of the plant's performance in the environment. We discuss exemplary reports covering the implications of metabolomics, addressing metabolic changes in vegetable plants during crop domestication, stage-dependent growth, fruit development, nutri-metabolic capabilities, climatic impacts, plant-microbe-pest interactions and anthropogenic activities. Efforts leading to identify biomarker metabolites, candidate proteins and the genes responsible for plant health, defense mechanisms and nutri-rich crop produce are documented. With the insights on metabolite-QTL (mQTL) driven genetic architecture, molecular breeding in vegetable crops can be revolutionized for developing better nutritional capabilities, improved tolerance against diseases/pests and enhanced climate resilience in plants.


Subject(s)
Small Molecule Libraries , Vegetables , Humans , Metabolomics/methods , Crops, Agricultural/genetics , Biomarkers
12.
Physiol Plant ; 173(4): 1729-1764, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33547804

ABSTRACT

Melon (Cucumis melo L.) is an important cucurbit and has been considered as a model plant for studying sex determination. The four most common sexual morphotypes in melon are monoecious (A-G-M), gynoecious (--ggM-), andromonoecious (A-G-mm), and hermaphrodite (--ggmm). Sex expression in melons is complex, as the genes and associated networks that govern the sex expression are not fully explored. Recently, RNA-seq transcriptomic profiling, ChIP-qPCR analysis integrated with gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathways predicted the differentially expressed genes including sex-specific ACS and ACO genes, in regulating the sex-expression, phytohormonal cross-talk, signal transduction, and secondary metabolism in melons. Integration of transcriptional control through genetic interaction in between the ACS7, ACS11, and WIP1 in epistatic or hypostatic manner, along with the recruitment of H3K9ac and H3K27me3, epigenetically, overall determine sex expression. Alignment of protein sequences for establishing phylogenetic evolution, motif comparison, and protein-protein interaction supported the structural conservation while presence of the conserved hydrophilic and charged residues across the diverged evolutionary group predicted the functional conservation of the ACS protein. Presence of the putative cis-binding elements or DNA motifs, and its further comparison with DAP-seq-based cistrome and epicistrome of Arabidopsis, unraveled strong ancestry of melons with Arabidopsis. Motif comparison analysis also characterized putative genes and transcription factors involved in ethylene biosynthesis, signal transduction, and hormonal cross-talk related to sex expression. Overall, we have comprehensively reviewed research findings for a deeper insight into transcriptional and epigenetic regulation of sex expression and flower development in melons.


Subject(s)
Cucumis melo/genetics , Epigenesis, Genetic , Flowers/physiology , Flowers/genetics , Gene Expression Regulation, Plant , Phylogeny
13.
Metab Brain Dis ; 36(7): 1591-1626, 2021 10.
Article in English | MEDLINE | ID: mdl-34387831

ABSTRACT

Neuroinflammation is one of the host defensive mechanisms through which the nervous system protects itself from pathogenic and or infectious insults. Moreover, neuroinflammation occurs as one of the most common pathological outcomes in various neurological disorders, makes it the promising target. The present review focuses on elaborating the recent advancement in understanding molecular mechanisms of neuroinflammation and its role in the etiopathogenesis of various neurological disorders, especially Alzheimer's disease (AD), Parkinson's disease (PD), and Epilepsy. Furthermore, the current status of anti-inflammatory agents in neurological diseases has been summarized in light of different preclinical and clinical studies. Finally, possible limitations and future directions for the effective use of anti-inflammatory agents in neurological disorders have been discussed.


Subject(s)
Nervous System Diseases/etiology , Neuroinflammatory Diseases/etiology , Alzheimer Disease/etiology , Anti-Inflammatory Agents/therapeutic use , Autophagy , Cytokines/physiology , Humans , Inflammasomes/physiology , Monocytes/physiology , Nervous System Diseases/drug therapy , Neuroglia/physiology , Neuroinflammatory Diseases/complications , Oxidative Stress , T-Lymphocytes/physiology
14.
Plant Dis ; 105(9): 2595-2600, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33393356

ABSTRACT

Whitefly (Bemisia tabaci)-transmitted begomoviruses cause severe diseases in numerous economically important dicotyledonous plants. Okra enation leaf curl disease (OELCuD) has emerged as a serious threat to okra (Abelmoschus esculentus L. Moench) cultivation in the Indian subcontinent. This study reports the association of a monopartite begomovirus (bhendi yellow vein mosaic virus; BYVMV) and betasatellite (bhendi yellow vein mosaic betasatellite; BYVB) with OELCuD in the Mau region of Uttar Pradesh, India. The BYVMV alone inoculated Nicotiana benthamiana and A. esculentus cv. Pusa Sawani plants developed mild symptoms. Co-inoculation of BYVMV and BYVB resulted in a reduced incubation period, an increased symptom severity, and an enhanced BYVMV accumulation by Southern hybridization and quantitative real-time PCR. This is the first study that satisfies Koch's postulates for OELCuD in its natural host. Activities of various antioxidative enzymes were significantly increased in the virus-inoculated okra plants. Differential responses in various biochemical components (such as photosynthetic pigments, phenol, proline, and sugar) in diseased okra plants were observed. This change in phytochemical responses is significant in understanding its impact on virus pathogenesis and disease development.


Subject(s)
Abelmoschus , Begomovirus , Abelmoschus/genetics , Begomovirus/genetics , DNA, Viral , Phylogeny , Phytochemicals , Plant Diseases
15.
Phys Chem Chem Phys ; 22(21): 12294-12300, 2020 Jun 04.
Article in English | MEDLINE | ID: mdl-32432250

ABSTRACT

Rare earth nickelate perovskites have very wide uses, as magnetic insulators, as well as being conducting materials for the various components of solid oxide fuel cells (SOFCs) due to them undergoing an insulator to metal transition below operating temperature. In SOFCs, the microstructural design of electrode materials is an important aspect for electron and oxygen ion conduction at the electrolyte-electrode and electrode-air interfaces. To investigate this feature, a Ruddlesen-Popper structured layered perovskite, (SmSr)NiO4-δ, was synthesized at different sintering temperatures using a solid-state reaction technique. Porous and dense microstructures were obtained at sintering temperatures of 1250 and 1425 °C, respectively. The influence of electrocatalysis on the structures of both surfaces was studied comprehensively. Post cyclic voltammetry structural studies show the presence of Ni-(OH)2 and Ni-OOH species for the samples, respectively, suggesting that they undergo different oxygen reduction reaction mechanisms.

16.
Phys Chem Chem Phys ; 21(27): 14701-14712, 2019 Jul 10.
Article in English | MEDLINE | ID: mdl-31218309

ABSTRACT

The paradigm that chemical synthesis reduces the sintering temperature as compared to solid state synthesis seems to be violated in the case of the PrBaCo2O6-δ double perovskite. The sintering temperatures for pure phase samples synthesized through the solid state route (P-SSR) and the auto-combustion route (P-ACR) were found to be 1050 and 1150 °C, respectively. The porous microstructure of P-SSR is suitable for SOFC cathode materials while that of P-ACR is pore free. High-resolution transmission electron microscopy, Raman and scanning tunneling microscopy studies reveal that there is crystal growth on a smooth surface with a preferred orientation. Our results show that this anomalous synthesis behaviour is due to anisotropic surface nucleation growth. Thermodynamically, the higher decomposition temperature in the chemical route is due to stronger electron-phonon coupling and the higher value of change in entropy. The variation in the Co-O-Co bond angle reveals Jahn-Teller vibrational anisotropy in the-b plane leading to the anisotropic synthesis behaviour. This anisotropy is the reason for the violation of the paradigm.

17.
J Phycol ; 55(1): 60-73, 2019 02.
Article in English | MEDLINE | ID: mdl-30118147

ABSTRACT

The objective of the present study was to characterize intrinsic physiological and biochemical properties of the wall-less unicellular cholorophyte Dunaliella salina isolated from a hypersaline Sambhar Lake. The strain grew optimally at 0.5 M NaCl and 16:8 h L:D photoperiod along with maintaining low level of intracellular Na+ even at higher salinity, emphasizing special features of its cell membranes. It was observed that the cells experienced stress beyond 2 M NaCl as evidenced by increased intracellular reactive oxygen species and antioxidative enzymes, nevertheless proline and malondialdehyde content declined sharply accompanied by higher neutral lipid accumulation. Salinity exceeding 2 M resulted decrease in photosynthetic quantum yield (Fv/Fm) and enhanced glycerol synthesis accompanied by leakage. Super oxide dismutase seemed to play a pivotal role in antioxidative defense as eight isoforms were expressed differentially while catalase and glutathione peroxidase showing no significant change in their expression at higher salinity. The ability of D. salina to grow in range of salinities by sustaining healthy photosynthetic apparatus along with accumulation of valuable products made this alga an ideal organism that can be exploited as resource for biofuel and commercial products.


Subject(s)
Chlorophyta , India , Lakes , Salinity , Sodium Chloride
19.
Phys Chem Chem Phys ; 20(27): 18800-18810, 2018 Jul 11.
Article in English | MEDLINE | ID: mdl-29964285

ABSTRACT

A piezoelectric material KNbO3 has been co-substituted with the magnetic ions Sm3+ and Fe3+ in order to explore the relation between piezoelectricity and magnetism. The samples K1-xSmxNb1-xFexO3 [x = 0.0-0.1] were synthesized using a solid state reaction route, after estimating the structural stability with the substitution. Structural studies were employed using XRD with Rietveld refinement and Raman analysis suggesting Amm2 symmetry. Also, the transition temperature was observed to change with the increase in Sm and Fe content. This transition temperature was also confirmed through high temperature XRD and high temperature Raman results. The dielectric and piezoelectric properties were found to be in correlation with the intensity of Raman modes for substituted samples, indicating better ferroelectricity at x = 0.05. A correlation between piezoelectric and magnetic properties was established in terms of the coercive field and exchange energy.

20.
Phys Chem Chem Phys ; 19(38): 26285-26295, 2017 Oct 04.
Article in English | MEDLINE | ID: mdl-28933470

ABSTRACT

BiFeO3 (BFO) systems co-modified with Ti, Sm and Sm-Ti have been investigated for piezoelectricity together with dielectric and multiferroic properties. Structural studies revealed the coexistence of orthorhombic and rhombohedral (R3c) phases for x > 0.12. Impurity phases were shown to have hardly any effect on the remanent magnetization, which rather depends on the Fe-O-Fe bond angle. The dielectric loss was reduced considerably by substitution. A correlation between the piezoelectric coefficient and tetragonality was observed in these samples. BFO co-substituted with Sm-Ti exhibited a high piezoelectric coefficient with better ferroic properties, which revealed a unique combination of green piezoelectricity and multiferroicity.

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