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Edamana Prasad

Bio: Edamana Prasad is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Dendrimer & Ether. The author has an hindex of 27, co-authored 100 publications receiving 2263 citations. Previous affiliations of Edamana Prasad include Texas Tech University & Indian Institutes of Technology.


Papers
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Journal ArticleDOI
TL;DR: The developed hydrogel exhibits self-healing properties at neutral pH, high swelling ability, high elasticity, and excellent mechanical strength, and the mechanistic analysis indicated the presence of pseudo-second-order reaction kinetics.
Abstract: In this work, a self-healing hydrogel has been prepared using in situ polymerization of acrylic acid and acrylamide in the presence of glycogen. The hydrogel was characterized using NMR, SEM, FT-IR, rheology, and dynamic light scattering (DLS) studies. The developed hydrogel exhibits self-healing properties at neutral pH, high swelling ability, high elasticity, and excellent mechanical strength. The hydrogel exhibits modulus values (G′, G″) as high as 106 Pa and shows an exceptionally high degree of swelling ratio (∼3.5 × 103). Further, the polymer based hydrogel adsorbs toxic metal ions (Cd2+, Pb2+, and Hg2+) and organic dyes (methylene blue and methyl orange) from contaminated water with remarkable efficiency (90–98%). The mechanistic analysis indicated the presence of pseudo-second-order reaction kinetics. The reusability of the hydrogel has been demonstrated by repeating the adsorption–desorption process over five cycles with identical results in the adsorption efficiency.

24 citations

Journal ArticleDOI
TL;DR: The results indicate that the reducing power of LnX2 has a large impact on not only the pinacol coupling/reduction product ratio of ketones but also on other substrates in which there are competing coupling and reduction reactions.
Abstract: The use of microwave heating in lanthanide(II) halide (LnX2=SmBr2, SmI2, and YbI2) mediated reduction and coupling reactions has been investigated for a variety of functional groups including α,β-unsaturated esters, aldehydes, ketones, imines, and alkyl halides. Good to quantitative transformations were obtained within a few minutes without the addition of any co-solvents, such as hexamethyl phosphoramide (HMPA). The redox potential of YbI2 in tetrahydrofuran (THF) has been determined as −1.02±0.05 V (versus Ag/AgNO3) by cyclic voltammetry. A large selectivity difference in various reactions was observed depending on the redox potential of the LnX2 reagent. The more powerful reductant, SmBr2, afforded mainly pinacol-coupling products of ketones whereas the weaker reductant YbI2 afforded mainly reduction products. The results indicate that the reducing power of LnX2 has a large impact on not only the pinacol coupling/reduction product ratio of ketones but also on other substrates in which there are competing coupling and reduction reactions. The use of in situ generated LnX2 has also been explored and proven useful in many of these reactions.

22 citations

Journal ArticleDOI
TL;DR: In this article, a turn-on fluorescent probe based on denatured bovine serum albumin (BSA)-Pyronin Y complex (PYdBSA) was used to detect common contaminant ions (Hg2+, Cd2+, Cu2+, and Pb2+) found in wastewater.
Abstract: A “turn on” fluorescent probe based on denatured bovine serum albumin (BSA)–Pyronin Y complex (PYdBSA) has been prepared using a one pot approach. This probe can detect nanomolar concentrations of common contaminant ions (Hg2+, Cd2+, Cu2+, and Pb2+) found in wastewater. The probe shows the highest fluorescence response for Hg2+ (relative intensity set to 100%) and a very good response for Cd2+ (60%), Cu2+ (50%), and Pb2+ (20%). The probe is water-soluble and has photo excitation in the visible region (530 nm). More interestingly, the presence of the contaminant ions under consideration can be visually detected due to the distinct color formation upon addition of the analytes in micromolar (1 μM) concentrations. The limit of detection (LOD) with fluorometry is 9 nM for Hg2+ (<2 ppb; consistent with standards given by the U.S. Environmental Protection Agency). This probe signal is found to be intact even in the presence of other metal ions such as Zn2+, Co2+, Fe2+, Ag+, K+, Na+, Al3+, Ca2+, Fe3+, Ni2+, Sb3+...

22 citations

Journal ArticleDOI
TL;DR: In this article, the authors used ultrasound (20 kHz) to synthesize samarium(II) diiodide and triflate reductants in a wide range of solvents including alcohols.
Abstract: Ultrasound (20 kHz) was used to prepare samarium(II) diiodide (SmI2), samarium(II) dibromide (SmBr2), and samarium(II) triflate (SmOTf)2. The method described herein provides a straightforward and rapid approach to the synthesis of SmII compounds not accessible by other means. Of particular importance is the fact that this approach can be used to produce SmII-based reductants in a wide range of solvents including alcohols. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

21 citations

Journal ArticleDOI
TL;DR: Results from the study indicate that absence of interplay between the excited states from a dark Intramolecular Charge Transfer (ICT) state to Locally Excited state (LE) in m-AnCN is the primary reason behind the observed difference in the emission properties of the aggregates.
Abstract: Design and synthesis of molecular assemblies which exhibit aggregation-induced emission (AIE) have attracted persistent attention in recent years. However, studies on the impact of the substitution position in isostructural molecules to regulate aggregation-induced emission (AIE) or convert aggregation-caused quenching (ACQ) to AIE have not been reported to date. In the present study, aggregation properties of two isostructural fluorophores viz. (E)-4-(2-(anthracen-9-yl)vinyl)benzonitrile (p-AnCN) and (E)-3-(2-(anthracen-9-yl)vinyl)benzonitrile (m-AnCN), with different substitution positions have been evaluated. It was observed that m-AnCN exhibits an ACQ behavior, whereas, p-AnCN exhibits enhanced emission upon aggregation. Upon aggregation, c.a. 1.4-fold decrease in luminescence quantum yield has been observed for m-AnCN, whereas, c.a. 11-fold enhancement in luminescence quantum yield has been achieved for p-AnCN. Results from the study indicate that absence of interplay between the excited states from a dark Intramolecular Charge Transfer (ICT) state to Locally Excited state (LE) in m-AnCN is the primary reason behind the observed difference in the emission properties of the aggregates. Thus, modulation of ACQ-AIE properties has been achieved using isostructural organic fluorophores, which in turn can be used as a versatile strategy to achieve AIE-luminophores. Further, the AIE active p-AnCN aggregates have been utilized to generate three-component white light emission with CIE coordinates of (0.33, 0.33).

21 citations


Cited by
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01 Jan 2016
TL;DR: The principles of fluorescence spectroscopy is universally compatible with any devices to read and is available in the digital library an online access to it is set as public so you can download it instantly.
Abstract: Thank you very much for downloading principles of fluorescence spectroscopy. As you may know, people have look hundreds times for their favorite novels like this principles of fluorescence spectroscopy, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they cope with some harmful bugs inside their desktop computer. principles of fluorescence spectroscopy is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the principles of fluorescence spectroscopy is universally compatible with any devices to read.

2,960 citations

Journal ArticleDOI
TL;DR: The trends indicate that hydrogels that self-heal better also achieve self- healing faster, as compared to gels that only partially self- Healing, and the potential relevance of self-Healing hydrogel to the exciting research areas of 3D/4D printing, soft robotics, and assisted health technologies is highlighted.
Abstract: Over the past few years, there has been a great deal of interest in the development of hydrogel materials with tunable structural, mechanical, and rheological properties, which exhibit rapid and autonomous self-healing and self-recovery for utilization in a broad range of applications, from soft robotics to tissue engineering. However, self-healing hydrogels generally either possess mechanically robust or rapid self-healing properties but not both. Hence, the development of a mechanically robust hydrogel material with autonomous self-healing on the time scale of seconds is yet to be fully realized. Here, the current advances in the development of autonomous self-healing hydrogels are reviewed. Specifically, methods to test self-healing efficiencies and recoveries, mechanisms of autonomous self-healing, and mechanically robust hydrogels are presented. The trends indicate that hydrogels that self-heal better also achieve self-healing faster, as compared to gels that only partially self-heal. Recommendations to guide future development of self-healing hydrogels are offered and the potential relevance of self-healing hydrogels to the exciting research areas of 3D/4D printing, soft robotics, and assisted health technologies is highlighted.

871 citations

Journal ArticleDOI
TL;DR: This study highlights the importance of knowing the carrier and removal status of canine coronavirus in the diet of animals and also investigates its role in the establishment and disposal of infectious diseases.
Abstract: Detection Ying Zhou,†,‡ Jun Feng Zhang, and Juyoung Yoon*,† †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea ‡Key Laboratory of Medicinal Chemistry for Natural Resource, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, P. R. China

859 citations

01 Jan 2007
Abstract: Fogging occurs when moisture condensation takes the form of accumulated droplets with diameters larger than 190 nm or half of the shortest wavelength (380 nm) of visible light. This problem may be effectively addressed by changing the affinity of a material’s surface for water, which can be accomplished via two approaches: i) the superhydrophilic approach, with a water contact angle (CA) less than 5°, and ii) the superhydrophobic approach, with a water CA greater than 150°, and extremely low CA hysteresis. To date, all techniques reported belong to the former category, as they are intended for applications in optical transparent coatings. A well-known example is the use of photocatalytic TiO2 nanoparticle coatings that become superhydrophilic under UV irradiation. Very recently, a capillary effect was skillfully adopted to achieve superhydrophilic properties by constructing 3D nanoporous structures from layer-by-layer assembled nanoparticles. The key to these two “wet”-style antifogging strategies is for micrometer-sized fog drops to rapidly spread into a uniform thin film, which can prevent light scattering and reflection from nucleated droplets. Optical transparency is not an intrinsic property of antifogging coatings even though recently developed antifogging coatings are almost transparent, and the transparency could be achieved by further tuning the nanoparticle size and film thickness. To our knowledge, the antifogging coatings may also be applied to many fields that do not require optical transparency, including, for example, paints for inhibiting swelling and peeling issues and metal surfaces for preventing corrosion. These types of issues, which are caused by adsorption of moisture, are hard to solve by the superhydrophilic approach because of its inherently “wet” nature. Thus, a “dry”-style antifogging strategy, which consists of a novel superhydrophobic technique that can prevent moisture or microscale fog drops from nucleating on a surface, is desired. Recent bionic researches have revealed that the self-cleaning ability of lotus leaves and the striking ability of a water-strider’s legs to walk on water can be attributed to the ideal superhydrophobicity of their surfaces, induced by special microand nanostructures. To date, the biomimetic fabrication of superhydrophobic microand/or nanostructures has attracted considerable interest, and these types of materials can be used for such applications as self-cleaning coatings and stain-resistant textiles. Although a superhydrophobic technique inspired by lotus leaves is expected to be able to solve such fogging problems because the water droplets can not remain on the surface, there are no reports of such antifogging coatings. Very recently, researchers from General Motors have reported that the surfaces of lotus leaves become wet with moisture because the size of the fog drops are at the microscale—so small that they can be easily trapped in the interspaces among micropapillae. Thus, lotuslike surface microstructures are unsuitable for superhydrophobic antifogging coatings, and a new inspiration from nature is desired for solving this problem. In this communication, we report a novel, biological, superhydrophobic antifogging strategy. It was found that the compound eyes of the mosquito C. pipiens possess ideal superhydrophobic properties that provide an effective protective mechanism for maintaining clear vision in a humid habitat. Our research indicates that this unique property is attributed to the smart design of elaborate microand nanostructures: hexagonally non-close-packed (ncp) nipples at the nanoscale prevent microscale fog drops from condensing on the ommatidia surface, and hexagonally close-packed (hcp) ommatidia at the microscale could efficiently prevent fog drops from being trapped in the voids between the ommatidia. We also fabricated artificial compound eyes by using soft lithography and investigated the effects of microand nanostructures on the surface hydrophobicity. These findings could be used to develop novel superhydrophobic antifogging coatings in the near future. It is known that mosquitoes possess excellent vision, which they exploit to locate various resources such as mates, hosts, and resting sites in a watery and dim habitat. To better understand such remarkable abilities, we first investigated the interaction between moisture and the eye surface. An ultrasonic humidifier was used to regulate the relative humidity of the atmosphere and mimic a mist composed of numerous tiny water droplets with diameters less than 10 lm. As the fog was C O M M U N IC A IO N

756 citations