scispace - formally typeset
Search or ask a question

Showing papers by "Indian Institute of Science published in 2016"


Journal ArticleDOI
Daniel J. Klionsky1, Kotb Abdelmohsen2, Akihisa Abe3, Joynal Abedin4  +2519 moreInstitutions (695)
TL;DR: In this paper, the authors present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macro-autophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular assays, we hope to encourage technical innovation in the field.

5,187 citations


Journal ArticleDOI
07 Oct 2016-Science
TL;DR: N nanoscale phase stabilization of CsPbI3 quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices and describe the formation of α-CsP bI3 QD films that are phase-stable for months in ambient air.
Abstract: We show nanoscale phase stabilization of CsPbI 3 quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices. CsPbI 3 is an all-inorganic analog to the hybrid organic cation halide perovskites, but the cubic phase of bulk CsPbI 3 (α-CsPbI 3 )—the variant with desirable band gap—is only stable at high temperatures. We describe the formation of α-CsPbI 3 QD films that are phase-stable for months in ambient air. The films exhibit long-range electronic transport and were used to fabricate colloidal perovskite QD photovoltaic cells with an open-circuit voltage of 1.23 volts and efficiency of 10.77%. These devices also function as light-emitting diodes with low turn-on voltage and tunable emission.

2,103 citations


Journal ArticleDOI
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam  +2283 moreInstitutions (141)
TL;DR: Combined fits to CMS UE proton–proton data at 7TeV and to UEProton–antiproton data from the CDF experiment at lower s, are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13.
Abstract: New sets of parameters ("tunes") for the underlying-event (UE) modeling of the PYTHIA8, PYTHIA6 and HERWIG++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE data at sqrt(s) = 7 TeV and to UE data from the CDF experiment at lower sqrt(s), are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13 TeV. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons of the UE tunes to "minimum bias" (MB) events, multijet, and Drell-Yan (q q-bar to Z / gamma* to lepton-antilepton + jets) observables at 7 and 8 TeV are presented, as well as predictions of MB and UE observables at 13 TeV.

686 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provide a state-of-the-art review of guided wave based structural health monitoring (SHM) and highlight the future directions and open areas of research in guided wave-based SHM.
Abstract: The paper provides a state of the art review of guided wave based structural health monitoring (SHM). First, the fundamental concepts of guided wave propagation and its implementation for SHM is explained. Following sections present the different modeling schemes adopted, developments in the area of transducers for generation, and sensing of wave, signal processing and imaging technique, statistical and machine learning schemes for feature extraction. Next, a section is presented on the recent advancements in nonlinear guided wave for SHM. This is followed by section on Rayleigh and SH waves. Next is a section on real-life implementation of guided wave for industrial problems. The paper, though briefly talks about the early development for completeness,. is primarily focussed on the recent progress made in the last decade. The paper ends by discussing and highlighting the future directions and open areas of research in guided wave based SHM.

664 citations


Journal ArticleDOI
TL;DR: These results confirm a negligible influence of surface defects in trapping charge carriers, which in turn results into desirable intrinsic transport properties, from the perspective of device applications, such as remarkably high carrier mobility, large diffusion length, and high luminescence quantum yield.
Abstract: Colloidal CsPbBr3 perovskite nanocrystals (NCs) have emerged as an excellent light emitting material in last one year. Using time domain and time-resolved THz spectroscopy and density functional theory based calculations, we establish 3-fold free carrier recombination mechanism, namely, nonradiative Auger, bimolecular electron–hole recombination, and inefficient trap-assisted recombination in 11 nm sized colloidal CsPbBr3 NCs. Our results confirm a negligible influence of surface defects in trapping charge carriers, which in turn results into desirable intrinsic transport properties, from the perspective of device applications, such as remarkably high carrier mobility (∼4500 cm2 V–1 s–1), large diffusion length (>9.2 μm), and high luminescence quantum yield (80%). Despite being solution processed and possessing a large surface to volume ratio, this combination of high carrier mobility and diffusion length, along with nearly ideal photoluminescence quantum yield, is unique compared to any other colloidal q...

452 citations


Proceedings ArticleDOI
01 Oct 2016
TL;DR: This work uses a combination of deep and shallow, fully convolutional networks to predict the density map for a given crowd image, and shows that this combination is used for effectively capturing both the high-level semantic information and the low-level features, necessary for crowd counting under large scale variations.
Abstract: Our work proposes a novel deep learning framework for estimating crowd density from static images of highly dense crowds. We use a combination of deep and shallow, fully convolutional networks to predict the density map for a given crowd image. Such a combination is used for effectively capturing both the high-level semantic information (face/body detectors) and the low-level features (blob detectors), that are necessary for crowd counting under large scale variations. As most crowd datasets have limited training samples (

429 citations


Journal ArticleDOI
TL;DR: In this article, the use of formic acid as a reversible source for hydrogen storage is discussed, where the authors focus on recent developments in this direction, which will likely give access to a variety of low-cost and highly efficient rechargeable hydrogen fuel cells within the next few years by using suitable homogeneous metal complex/heterogeneous metal nanoparticle-based catalysts under ambient reaction conditions.

407 citations


Journal ArticleDOI
TL;DR: In this article, the authors elucidate how halide compositions control both of these correlated parameters of CsPbX3 nanocrystals and show that the valence band maximum (VBM) shifts significantly to higher energies by 0.80 eV, from X = Cl to Br to I, whereas the shift in the conduction band minimum (CBM) is small (0.19 eV) but systematic.
Abstract: Colloidal CsPbX3 (X = Cl, Br, and I) nanocrystals have recently emerged as preferred materials for light-emitting diodes, along with opportunities for photovoltaic applications. Such applications rely on the nature of valence and conduction band edges and optical transitions across these edges. Here we elucidate how halide compositions control both of these correlated parameters of CsPbX3 nanocrystals. Cyclic voltammetry shows that the valence band maximum (VBM) shifts significantly to higher energies by 0.80 eV, from X = Cl to Br to I, whereas the shift in the conduction band minimum (CBM) is small (0.19 eV) but systematic. Halides contribute more to the VBM, but their contribution to the CBM is also not negligible. Excitonic transition probabilities for both absorption and emission of visible light decrease probably because of the increasing dielectric constant from X = Cl to Br to I. These band edge properties will help design suitable interfaces in both devices and heterostructured nanocrystals.

393 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of laser track direction on quasi-static tensile, fracture, fatigue crack growth, and unnotched fatigue properties was examined and the results were compared with those obtained on specimens produced through the conventional casting route.

373 citations


Journal ArticleDOI
TL;DR: This review outlines the most recent advancement in transplantation and tissue engineering technologies of ESCs, TSPSCs, MSCs, UC SCs, BMSCs, and iPSCs in regenerative medicine and discusses stem cells regenerative application in wildlife conservation.
Abstract: Regenerative medicine, the most recent and emerging branch of medical science, deals with functional restoration of tissues or organs for the patient suffering from severe injuries or chronic disease. The spectacular progress in the field of stem cell research has laid the foundation for cell based therapies of disease which cannot be cured by conventional medicines. The indefinite self-renewal and potential to differentiate into other types of cells represent stem cells as frontiers of regenerative medicine. The transdifferentiating potential of stem cells varies with source and according to that regenerative applications also change. Advancements in gene editing and tissue engineering technology have endorsed the ex vivo remodelling of stem cells grown into 3D organoids and tissue structures for personalized applications. This review outlines the most recent advancement in transplantation and tissue engineering technologies of ESCs, TSPSCs, MSCs, UCSCs, BMSCs, and iPSCs in regenerative medicine. Additionally, this review also discusses stem cells regenerative application in wildlife conservation.

366 citations


Journal ArticleDOI
TL;DR: It is found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway.
Abstract: Naturally occurring compounds are considered as attractive candidates for cancer treatment and prevention. Quercetin and ellagic acid are naturally occurring flavonoids abundantly seen in several fruits and vegetables. In the present study, we evaluate and compare antitumor efficacies of quercetin and ellagic acid in animal models and cancer cell lines in a comprehensive manner. We found that quercetin induced cytotoxicity in leukemic cells in a dose-dependent manner, while ellagic acid showed only limited toxicity. Besides leukemic cells, quercetin also induced cytotoxicity in breast cancer cells, however, its effect on normal cells was limited or none. Further, quercetin caused S phase arrest during cell cycle progression in tested cancer cells. Quercetin induced tumor regression in mice at a concentration 3-fold lower than ellagic acid. Importantly, administration of quercetin lead to ~5 fold increase in the life span in tumor bearing mice compared to that of untreated controls. Further, we found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway. Thus, our data suggests that quercetin can be further explored for its potential to be used in cancer therapeutics and combination therapy.

Posted Content
TL;DR: In this paper, a combination of deep and shallow, fully convolutional networks is used to predict the density map for a given crowd image, which is used for effectively capturing both the high-level semantic information (face/body detectors) and the low-level features (blob detectors), that are necessary for crowd counting under large scale variations.
Abstract: Our work proposes a novel deep learning framework for estimating crowd density from static images of highly dense crowds. We use a combination of deep and shallow, fully convolutional networks to predict the density map for a given crowd image. Such a combination is used for effectively capturing both the high-level semantic information (face/body detectors) and the low-level features (blob detectors), that are necessary for crowd counting under large scale variations. As most crowd datasets have limited training samples (<100 images) and deep learning based approaches require large amounts of training data, we perform multi-scale data augmentation. Augmenting the training samples in such a manner helps in guiding the CNN to learn scale invariant representations. Our method is tested on the challenging UCF_CC_50 dataset, and shown to outperform the state of the art methods.

Journal ArticleDOI
TL;DR: This system is the first example of a MOF-based system which absorbs both dichromate and permanganate ions, with the latter acting as a model for the radioactive contaminant pertechnetate.
Abstract: A three-dimensional water-stable cationic metal-organic framework (MOF) pillared by a neutral ligand and with Ni(II) metal nodes has been synthesized employing a rational design approach. Owing to the ordered arrangement of the uncoordinated tetrahedral sulfate (SO4 (2-) ) ions in the channels, the compound has been employed for aqueous-phase ion-exchange applications. The compound exhibits rapid and colorimetric aqueous-phase capture of environmentally toxic oxoanions (with similar geometries) in a selective manner. This system is the first example of a MOF-based system which absorbs both dichromate (Cr2 O7 (2-) ) and permanganate (MnO4 (-) ) ions, with the latter acting as a model for the radioactive contaminant pertechnetate (TcO4 (-) ).

Journal ArticleDOI
TL;DR: In this paper, the Fischer Tropsch (FT) reaction is used to convert biomass to liquid (BTL) transportation fuels via FT reaction and worldwide attempts to commercialize this process.
Abstract: Current global energy scenario and the environmental deterioration aspect motivates substituting fossil fuel with a renewable energy resource - especially transport fuel. This paper reviews the current status of trending biomass to liquid (BTL) conversion processes and focuses on the technological developments in Fischer Tropsch (FT) process. FT catalysts in use, and recent understanding of FT kinetics are explored. Liquid fuels produced via FT process from biomass derived syngas promises an attractive, clean, carbon neutral and sustainable energy source for the transportation sector. Performance of the FT process with various catalysts, operating conditions and its influence on the FT products are also presented. Experience from large scale commercial installations of FT plants, primarily utilizing coal based gasifiers, are discussed. Though biomass gasification plants exist for power generation via gas engines with power output of about 2 MWe; there are only a few equivalent sized FT plants for biomass derived syngas. This paper discusses the recent developments in conversion of biomass to liquid (BTL) transportation fuels via FT reaction and worldwide attempts to commercialize this process. All the data presented and analysed here have been consolidated from research experiences at laboratory scale as well as from industrial systems. Economic aspects of BTL are reviewed and compared. (C) 2015 Elsevier Ltd. All rights reserved.

Journal ArticleDOI
TL;DR: This report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials.
Abstract: Two porous hydrogen-bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra-high proton conduction values (σ) 0.75× 10−2 S cm−1 and 1.8×10−2 S cm−1 under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic-based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials.

Journal ArticleDOI
TL;DR: This work reviews syntheses, properties, and applications of various gel-nanocomposites assembled from different metal-based nanoparticles or nanocarbons with tailor-made supramolecular (small molecular) or polymeric physical organogels and hydrogels and presents appropriate rationale to explain most of these phenomena at the molecular level.
Abstract: Gel-nanocomposites are rapidly emerging functional advanced materials having widespread applications in materials and biological sciences. Herein, we review syntheses, properties, and applications of various gel-nanocomposites assembled from different metal-based nanoparticles or nanocarbons [fullerene, carbon nanotubes (CNTs), and graphenes] with tailor-made supramolecular (small molecular) or polymeric physical organogels and hydrogels. Dynamic supramolecular self-assembly of gelators prove to be excellent hosts for the incorporation of these dimensionally different nanomaterials. Thus, gel-nanocomposites doped with preformed/in situ synthesized nanoparticles show magnetic or near-infrared-responsive, catalytic or antibacterial properties. Fullerene-based gel-nanocomposites show applications in organic solar cells. Gel-nanocomposites based on CNTs and graphenes and their functionalized (covalent/noncovalent) analogues find interesting properties including electrical conductivity, viscoelasticity, therma...

Journal ArticleDOI
TL;DR: In this review, recent revelations about the excellent photophysical properties of boron containing compounds are discussed.

Journal ArticleDOI
TL;DR: In this article, the development and potential applications of such cationic or anionic frameworks have been discussed thoroughly in a review and the design principles governing the formation of such charge-polarized MOFs have been outlined through representative examples.

Journal ArticleDOI
TL;DR: The study, which reports the preparation of a series of exotic plastic crystals by design for the first time, demonstrates the potential of soft interactions for tuning the mechanical behavior of ordered molecular materials, including those from π-conjugated systems.
Abstract: Controlling mechanical properties of ordered organic materials remains a formidable challenge, despite their great potential for high performance mechanical actuators, transistors, solar cells, photonics, and bioelectronics. Here we demonstrate a crystal engineering approach to design mechanically reconfigurable, plastically flexible single crystals (of about 10) of three unrelated types of compounds by introducing active slip planes in structures via different noninterfering supramolecular weak interactions, namely van der Waals (vdW), π-stacking, and hydrogen bonding groups. Spherical hydrophobic groups, which assemble via shape complementarity (shape synthons), reliably form low energy slip planes, thus facilitating an impressive mechanical flexibility, which allowed molding the crystals into alphabetical characters to spell out “o r g a n i c c r y s t a l”. The study, which reports the preparation of a series of exotic plastic crystals by design for the first time, demonstrates the potential of soft ...

Journal ArticleDOI
TL;DR: This work shows that all studies of frequency stability report values several orders of magnitude larger than the limit imposed by thermomechanical noise, and proposes a new method to show this was due to the presence of frequency fluctuations, of unexpected level.
Abstract: Frequency stability is key to the performance of nanoresonators. This stability is thought to reach a limit with the resonator's ability to resolve thermally induced vibrations. Although measurements and predictions of resonator stability usually disregard fluctuations in the mechanical frequency response, these fluctuations have recently attracted considerable theoretical interest. However, their existence is very difficult to demonstrate experimentally. Here, through a literature review, we show that all studies of frequency stability report values several orders of magnitude larger than the limit imposed by thermomechanical noise. We studied a monocrystalline silicon nanoresonator at room temperature and found a similar discrepancy. We propose a new method to show that this was due to the presence of frequency fluctuations, of unexpected level. The fluctuations were not due to the instrumentation system, or to any other of the known sources investigated. These results challenge our current understanding of frequency fluctuations and call for a change in practices.

Journal ArticleDOI
TL;DR: The year 2016 saw a most dramatic scientific event in the month of February with the announcement of the observation of gravitational waves by the Advanced LIGO collaboration as mentioned in this paper, which used as its principles, laser inteferometry with two constituent ultra-quiet laboratories separated by thousands of kilometres.
Abstract: The year 2016 saw a most dramatic scientific event in the month of February with the announcement of the observation of gravitational waves by the Advanced LIGO collaboration. This complex experiment uses as its principles, laser inteferometry with two constituent ultra-quiet laboratories separated by thousands of kilometres.

Journal ArticleDOI
TL;DR: In this article, a relativistic Bethe-Salpeter Equation calculation (GW-BSE) was used to directly calculate excitonic properties from first-principles.
Abstract: The development of high efficiency perovskite solar cells has sparked a multitude of measurements on the optical properties of these materials. For the most studied methylammonium(MA)PbI3 perovskite, a large range (6–55 meV) of exciton binding energies has been reported by various experiments. The existence of excitons at room temperature is unclear. For the MAPbX3 perovskites we report on relativistic Bethe-Salpeter Equation calculations (GW-BSE). This method is capable to directly calculate excitonic properties from first-principles. At low temperatures it predicts exciton binding energies in agreement with the reported ‘large’ values. For MAPbI3, phonon modes present in this frequency range have a negligible contribution to the ionic screening. By calculating the polarization in time from finite temperature molecular dynamics, we show that at room temperature this does not change. We therefore exclude ionic screening as an explanation for the experimentally observed reduction of the exciton binding energy at room temperature and argue in favor of the formation of polarons.

Journal ArticleDOI
TL;DR: A comprehensive overview of the latest research achievements of SC-SM is presented, which outlines the associated transceiver design, the benefits and potential tradeoffs, the LSA aided multiuser (MU) transmission developments, the relevant open research issues as well as the potential solutions of this appealing transmission technique.
Abstract: The main limitations of employing large-scale antenna (LSA) architectures for broadband frequency-selective channels include, but are not limited to their complexity, power consumption, and the high cost of multiple radio frequency (RF) chains. Promising solutions can be found in the recently proposed family of single-carrier (SC) spatial modulation (SM) transmission techniques. Since the SM scheme’s transmit antenna (TA) activation process is carried out in the context of a SC-SM architecture, the benefits of a low-complexity and low-cost single-RF transmitter are maintained, while a high MIMO multiplexing gain can be attained. Moreover, owing to its inherent SC structure, the transmit signals of SC-SM have attractive peak power characteristics and a high robustness to RF hardware impairments, such as the RF carrier frequency offset (CFO) and phase noise. In this paper, we present a comprehensive overview of the latest research achievements of SC-SM, which has recently attracted considerable attention. We outline the associated transceiver design, the benefits and potential tradeoffs, the LSA aided multiuser (MU) transmission developments, the relevant open research issues as well as the potential solutions of this appealing transmission technique.

Journal ArticleDOI
TL;DR: In this paper, a micrometre-sized active Stirling engine was realized by periodically cycling a colloidal particle in a time-varying optical potential across bacterial baths characterized by different degrees of activity.
Abstract: Artificial microscale heat engines are prototypical models to explore the mechanisms of energy transduction in a fluctuation-dominated regime(1,2). The heat engines realized so far on this scale have operated between thermal reservoirs, such that stochastic thermodynamics provides a precise framework for quantifying their performance(3-6). It remains to be seen whether these concepts readily carry over to situations where the reservoirs are out of equilibrium(7), a scenario of particular importance to the functioning of synthetic(8,9) and biological(10) microscale engines and motors. Here, we experimentally realize a micrometre-sized active Stirling engine by periodically cycling a colloidal particle in a time-varying optical potential across bacterial baths characterized by different degrees of activity. We find that the displacement statistics of the trapped particle becomes increasingly non-Gaussian with activity and contributes substantially to the overall power output and the effciency. Remarkably, even for engines with the same energy input, differences in non-Gaussianity of reservoir noise results in distinct performances. At high activities, the effciency of our engines surpasses the equilibrium saturation limit of Stirling effciency, the maximum effciency of a Stirling engine where the ratio of cold to hot reservoir temperatures is vanishingly small. Our experiments provide fundamental insights into the functioning of micromotors and engines operating out of equilibrium.

Journal ArticleDOI
TL;DR: In this article, a one-step/one-pot strategy to synthesize phase pure Co2P nanoparticles encapsulated N, P dual-doped carbon nanotubes (denoted as co2P/CNT) is developed.

Journal ArticleDOI
TL;DR: The biomimetic studies strongly suggest that among the various metal ions probed for modeling the catalytic activity of CO and PHS, MnII/III based systems are so far the most promising candidates apart from the nature's choice CuII.

Journal ArticleDOI
TL;DR: Using density-functional theory, the microscopic understanding gained here unveils the challenges in exfoliation and controlling the functionalization of MXene, which is essential for its practical application.
Abstract: MXene, a two-dimensional layer of transition metal carbides/nitrides, showed great promise for energy storage, sensing, and electronic applications. MXene are chemically exfoliated from the bulk MAX phase; however, mechanistic understanding of exfoliation and subsequent functionalization of these technologically important materials is still lacking. Here, using density-functional theory we show that exfoliation of Ti3C2 MXene proceeds via HF insertion through edges of Ti3AlC2 MAX phase. Spontaneous dissociation of HF and subsequent termination of edge Ti atoms by H/F weakens Al–MXene bonds. Consequent opening of the interlayer gap allows further insertion of HF that leads to the formation of AlF3 and H2, which eventually come out of the MAX, leaving fluorinated MXene behind. Density of state and electron localization function shows robust binding between F/OH and Ti, which makes it very difficult to obtain controlled functionalized or pristine MXene. Analysis of the calculated Gibbs free energy (ΔG) shows...

Journal ArticleDOI
10 Feb 2016-Polymer
TL;DR: In this paper, the state of the art of designing polymer based nanocomposites containing nanoscopic particles with high electrical conductivity and complex microwave properties for enhanced EM attenuation is reviewed.

Journal ArticleDOI
TL;DR: The need to adopt intelligent processing approaches and targeted application-specific biocompatibility characterization, while fabricating mechanically stable and biologically functionalized 3D tissue equivalents is highlighted.
Abstract: In the last two decades, additive manufacturing (AM) has made significant progress towards the fabrication of biomaterials and tissue engineering constructs. One direction of research is focused on the development of mechanically stable implants with patient-specific size/shape and another direction has been to fabricate tissue-engineered scaffolds with designed porous architecture to facilitate vascularization. Among AM techniques, three dimensional powder printing (3DPP) is suitable for fabrication of bone related prosthetic devices, while three dimensional plotting (3DPL) is based on extrusion of biopolymers to create artificial tissues. In the present review, we aim to develop a better understanding of the science and engineering aspects of these low temperature AM techniques (3DPP and 3DPL) in the context of the bone-tissue engineering applications. While recognizing multiple property requirements of a 3D scaffold, the central theme is to discuss the critical roles played by the binder and powder properties together with the interplay among processing parameters in the context of the physics of binder-material interaction for the fabrication of implants with predefined architecture having structural complexity. An effort also has been exerted to discuss the existing challenges to translate the design concepts and material/binder formulations to develop implantable scaffolds with a more emphasis on bioceramics and biopolymers. Summarizing, this review highlights the need to adopt intelligent processing approaches and targeted application-specific biocompatibility characterization, while fabricating mechanically stable and biologically functionalized 3D tissue equivalents. (C) 2016 Elsevier B.V. All rights reserved.

Journal ArticleDOI
TL;DR: In this paper, the authors present recent developments in the area of metal-organic frameworks (MOFs) for aqueous phase TNP sensing and discuss strategies used to improve the sensing performance.
Abstract: 2,4,6-Trinitrophenol (TNP) is a highly explosive molecule that is also widely used in industrial processing on a large scale. During synthesis, processing and disposal, TNP is released to the environment especially to water streams, contaminating ground and surface water. TNP and its biologically transformed products like picramic acids have been identified as highly toxic species to biota and may lead to chronic diseases such as sycosis and cancer. Thus, aqueous phase detection of TNP becomes an imperative aspect for the design of any potential sensor. Metal–organic frameworks (MOFs) have emerged as an important class of sensors owing to their permanent porosity, designability and variety of signal transduction pathways. Luminescent MOFs (LMOFs) have shown great potential as sensors for various nitro explosives by modulation of their luminescence behaviour in the presence of nitro explosives. Most of the LMOFs detect nitro explosives in the vapour phase and/or in organic solvents while aqueous phase detection is rarely investigated. Herein we present recent developments in the area of LMOFs for aqueous phase TNP sensing and discuss strategies used to improve the sensing performance. Finally, based on our perspective, important aspects of LMOF performance needing immediate attention for future developments are provided.