Showing papers by "Aligarh Muslim University published in 2017"

Ethylene Role in Plant Growth, Development and Senescence: Interaction with Other Phytohormones

Abstract: The complex juvenile/maturity transition during a plant's life cycle includes growth, reproduction, and senescence of its fundamental organs: leaves, flowers, and fruits. Growth and senescence of leaves, flowers, and fruits involve several genetic networks where the phytohormone ethylene plays a key role, together with other hormones, integrating different signals and allowing the onset of conditions favorable for stage progression, reproductive success and organ longevity. Changes in ethylene level, its perception, and the hormonal crosstalk directly or indirectly regulate the lifespan of plants. The present review focused on ethylene's role in the development and senescence processes in leaves, flowers and fruits, paying special attention to the complex networks of ethylene crosstalk with other hormones. Moreover, aspects with limited information have been highlighted for future research, extending our understanding on the importance of ethylene during growth and senescence and boosting future research with the aim to improve the qualitative and quantitative traits of crops.

Review: biologically active pyrazole derivatives

Abstract: Nitrogen-containing heterocyclic compounds and their derivatives have historically been invaluable as a source of therapeutic agents. Pyrazole, which has two nitrogen atoms and aromatic character, provides diverse functionality and stereochemical complexity in a five-membered ring structure. In the past decade, studies have reported a growing body of data on different pyrazole derivatives and their innumerable physiological and pharmacological activities. In part, such studies attempted to reveal the wide range of drug-like properties of pyrazole derivatives along with their structure–activity relationships in order to create opportunities to harness the full potentials of these compounds. Here, we summarize strategies to synthesize pyrazole derivatives and demonstrate that this class of compounds can be targeted for the discovery of new drugs and can be readily prepared owing to recent advances in synthetic medicinal chemistry.

Structure, Genetics and Worldwide Spread of New Delhi Metallo-β-lactamase (NDM): a threat to public health

Abstract: The emergence of carbapenemase producing bacteria, especially New Delhi metallo-β-lactamase (NDM-1) and its variants, worldwide, has raised amajor public health concern. NDM-1 hydrolyzes a wide range of β-lactam antibiotics, including carbapenems, which are the last resort of antibiotics for the treatment of infections caused by resistant strain of bacteria. In this review, we have discussed bla NDM-1variants, its genetic analysis including type of specific mutation, origin of country and spread among several type of bacterial species. Wide members of enterobacteriaceae, most commonly Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and gram-negative non-fermenters Pseudomonas spp. and Acinetobacter baumannii were found to carry these markers. Moreover, at least seventeen variants of bla NDM-type gene differing into one or two residues of amino acids at distinct positions have been reported so far among different species of bacteria from different countries. The genetic and structural studies of these variants are important to understand the mechanism of antibiotic hydrolysis as well as to design new molecules with inhibitory activity against antibiotics. This review provides a comprehensive view of structural differences among NDM-1 variants, which are a driving force behind their spread across the globe.

Challenges in QCD matter physics --The scientific programme of the Compressed Baryonic Matter experiment at FAIR

Abstract: Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 ( $\sqrt{s_{NN}}=$ 2.7--4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials ( $\mu_B > 500$ MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter.

Plant Response to Engineered Metal Oxide Nanoparticles.

Abstract: All metal oxide nanoparticles influence the growth and development of plants. They generally enhance or reduce seed germination, shoot/root growth, biomass production and physiological and biochemical activities. Some plant species have not shown any physiological change, although significant variations in antioxidant enzyme activity and upregulation of heat shock protein have been observed. Plants have evolved antioxidant defence mechanism which involves enzymatic as well as non-enzymatic components to prevent oxidative damage and enhance plant resistance to metal oxide toxicity. The exact mechanism of plant defence against the toxicity of nanomaterials has not been fully explored. The absorption and translocation of metal oxide nanoparticles in different parts of the plant depend on their bioavailability, concentration, solubility and exposure time. Further, these nanoparticles may reach other organisms, animals and humans through food chain which may alter the entire biodiversity. This review attempts to summarize the plant response to a number of metal oxide nanoparticles and their translocation/distribution in root/shoot. The toxicity of metal oxide nanoparticles has also been considered to see if they affect the production of seeds, fruits and the plant biomass as a whole.

Nitric oxide signaling and its crosstalk with other plant growth regulators in plant responses to abiotic stress.

Abstract: Nitric oxide (NO) is a free radical molecule involved in an array of functions under physiological and adverse environmental conditions As other free radical molecules, NO biological action depends on its cellular concentration, acting as a signal molecule when produced at low concentration or resulting in cellular damage when produced at sufficiently high levels to trigger nitro-oxidative stress Over the last decade, significant progress has been made in characterizing NO metabolism and action mechanism, revealing that diverse biosynthetic routes can generate this free radical in plants and its action mainly occurs through posttranslational modification (nitration and S-nitrosylation) of target proteins Intricate crosstalk networks between NO and other signaling molecules have been described involving phytohormones, other second messengers, and key transcription factors This review will focus on our current understanding of NO interplay with phytohormones and other plant growth regulators under abiotic stress conditions

Health functionality of apigenin: A review

Abstract: Apigenin is being used by humans in the form of plant extract for the treatment of a number of disorders and inflammatory conditions, until its discovery as a core compound. Apigenin, chemically kn...

Photocatalytic performance of Fe-doped TiO2 nanoparticles under visible-light irradiation

Abstract: The present work focuses on the synthesis, characterization and photocatalytic activity of a nanosized Fe-doped TiO2 photocatalyst. The samples were synthesized by the sol–gel method and characterized by using techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), UV–visible spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy and Fourier-transform infrared (FTIR). The powder XRD spectra revealed that the synthesized samples are pure and crystalline in nature and show a tetragonal anatase phase of TiO2. The Raman spectroscopy also confirmed the formation of an anatase phase structure in both pure and Fe-doped TiO2 nanoparticles (NPs). The UV–visible and PL spectra illustrated the red shift in Fe-doped TiO2 NPs. The FTIR spectra indicated the vibrational band of the Ti–O lattice. The photocatalytic experimental results demonstrate that Fe-doped TiO2 NPs effectively degrade MB under visible-light illumination. Interestingly, the prepared TiO2 NPs with a dopant concentration of 3.0 mole% showed the maximum photocatalytic activity under investigation.

Anion selective pTSA doped polyaniline@graphene oxide-multiwalled carbon nanotube composite for Cr(VI) and Congo red adsorption.

Abstract: Multiwalled carbon nanotube (CNT)-graphene oxide (GO) composite was combined with polyaniline (Pani) using an oxidative polymerisation technique. The resulting Pani@GO-CNT was later doped with para toluene sulphonic acid (pTSA) to generate additional functionality. The functional groups exposed on the GO, Pani and pTSA were expected to impart a high degree of functionality to the pTSA-Pani@GO-CNT composite system. The composite was characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterisation results revealed the characteristics of Pani, GO, CNT, and pTSA, and suggested the successful formation of the pTSA-Pani@GO-CNT composite system. The composite was utilised successfully for the adsorptive removal of Cr(IV) and Congo red (CR) dye and the adsorption of both pollutants was found to be strongly dependent on the solution pH, adsorbate concentration, contact time, and reaction temperature. The maximum adsorption of Cr(IV) and CR was observed in an acidic medium at 30 °C. The kinetics for Cr(IV) and CR adsorption was studied using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The adsorption equilibrium data were also fitted to the Langmuir and Freundlich isotherm models. The thermodynamic results showed that the adsorption process was exothermic in nature. The present study provides a new methodology for the preparation of a highly functionalised Pani-based nanocomposite system and its potential applications to the adsorptive removal of a multicomponent pollutant system from an aqueous solution.

Multiple biomarker responses (serum biochemistry, oxidative stress, genotoxicity and histopathology) in Channa punctatus exposed to heavy metal loaded waste water.

Abstract: Experiments were conducted to investigate the health of fish Channa punctatus inhabiting heavy metal-loaded waste water. Heavy metals in the order of Fe > Mn > Zn > Co > Ni > Cu = Cr were present in the waste water. Gills had high metal load followed by liver and then kidney. Albumin, albumin to globulin (A:G) ratio, triglyceride, high density lipoprotein (HDL) and very low density lipoprotein (VLDL) were found to be lower but phospholipid, low density lipoprotein (LDL), total protein, lipid and cholesterol were higher as compared to the reference. Oxidative stress markers such as superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST) and lipid peroxidation (LPO) were significantly higher in all tissues, whereas reduced glutathione (GSH) levels were comparatively low. Damage to DNA was observed with significantly higher mean tail length of comets in the exposed fish gill cells (30.9 µm) followed by liver (24.3 µm) and kidney (20.6 µm) as compared to reference fish (5.2, 4.8 and 5.9 µm respectively). Histopathology in gill, liver and kidney also showed marked damage. Integrated biochemical, oxidative stress, genotoxicity and histopathological findings are valuable biomarkers for native fish adaptive patterns, and monitoring of water quality/pollution of freshwater ecosystems.

One-step hydrothermal synthesis of Bi-TiO2 nanotube/graphene composites: An efficient photocatalyst for spectacular degradation of organic pollutants under visible light irradiation

Abstract: In the present study, we have adopted a simple one-pot alkaline hydrothermal route to synthesize Bi-doped TiO2NT/graphene composites by using different wt% of Bi with an aim to achieve the excellent photocatalytic activity under visible light source. The nature of GO is changed to deoxygenated graphene with simultaneous embedding of Bi into TiO2 nanotube (TNT), during hydrothermal process. XRD and FTIR analysis confirm the successful conversion of GO to deoxygenated graphene. EPR analysis reveals the co-existence of Ti3+ ion with oxygen vacancy, which is created by the Bi doping. The photocatalytic activity of the prepared samples is measured by the degradation of aqueous suspensions of methylene blue (MB) and Dinoseb (phenolic herbicide), under visible-light irradiation. The prepared TiO2NT/graphene composite with 2-wt% bismuth (2-BTNTG) has shown the improved photocatalytic activity as compared to their counterparts. The improved photocatalytic activity is associated to the synergistic effect of graphene and Bi-TNT, which facilitate the interfacial charge transfer and enhances the efficiency of light harvesting in the visible region. Moreover, the underlying mechanism involving photocatalytic degradation of organic pollutants over 2-BTNTG is explored by using trapping experiments, suggesting that the .OH radicals solely contributed to degradation.

Biofilms in Endodontics-Current Status and Future Directions.

Abstract: Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal.

Invited review: Physics potential of the ICAL detector at the India-based Neutrino Observatory (INO)

Abstract: The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.

Microstructural properties and enhanced photocatalytic performance of Zn doped CeO 2 nanocrystals.

Abstract: The microstructural, optical and photocatalytic properties of undoped and 5% Zn doped CeO2 nanocrystals (NCs) have been explored through various analytical techniques, viz. powder x-ray diffraction (PXRD), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-visible, Raman and photoluminescence (PL) spectroscopy. XRD data analysis revealed face centred cubic (FCC) crystal symmetry of the samples with average crystallite size in the range of 19–24 nm. XPS results confirmed that the Zn ions exist in +2 states and successfully incorporated into the CeO2 matrix. Internal structure and morphology observed by TEM exhibited almost uniform cubical shape of the particles of average size ~20–26 nm. The enegy bandgap of undoped and Zn doped CeO2 NCs had a direct transition of 3.46 eV and 3.57 eV respectively as estimated by the optical absorption data. The increase in the bandgap revealed blue shift of absorption edge due to the quantum confinement effects. The NCs exhibited an inherent luminescence emission peak at ~408 nm in PL spectra. Improvement in the photocatalytic activity was observed for Zn incorporated sample attributed to the enhanced light absorption or/and fall in charge recombination rate between CeO2 and Zn.