ananya chowdhury - Academia.edu (original) (raw)

Papers by ananya chowdhury

Materials Advances

Hollow particles can be modelled as pseudo-2 dimensional nanostructures. The electrochemical perf... more Hollow particles can be modelled as pseudo-2 dimensional nanostructures. The electrochemical performance of such novel structures supersedes that of their solid counterparts by many folds.

ACS Applied Energy Materials

International Journal of Hydrogen Energy

Layered double-hydroxides (LDHs) are superior to the conventional (Transition Metal Oxides) TMOs ... more Layered double-hydroxides (LDHs) are superior to the conventional (Transition Metal Oxides) TMOs as their lamellar morphology accommodates higher active sites contributing to the facile electron transfer towards the material degradation relations, thus attracts an immense attention for catalysis application. Moreover, the high catalytic activity of LDHs is linked to their facile anion exchange, specific electronic structures, and versatile chemical compositions. Recently, LDHs with bimetallic or ternary combinations are preferably used for hydrogenation of pnitrophenol, a toxic and carcinogenic pollutant commonly found in industrial wastewater. Herein, a cost-effective co-precipitation fabrication protocol to obtain Ni-Co layered double hydroxide is proposed. The well-defined arrangement of active sites in the 2D structure of LDH, and the synergistic catalytic effect of Ni and Co greatly improves the efficiency for the conversion of p-nitrophenol (p-NP) to p-aminophenol (p-AMP). The catalytic performance at higher temperatures is also shown. The obtained results are further extended to explore the advantage of Ni-Co LDH as an electrocatalyst for Hydrogen Evolution Reaction (HER).

Materials Chemistry and Physics

Electrochemical Science Advances, 2021

Journal of Alloys and Compounds, 2022

BIRDEM Medical Journal, 2021

Pulmonary aspergillosis is an uncommon condition and at the same time very much challenging to di... more Pulmonary aspergillosis is an uncommon condition and at the same time very much challenging to diagnose and difficult to treat. Here, we present two cases of chronic pulmonary aspergillosis, who presented with with chronic low-grade fever, refractory and distressing cough and haemoptysis. The first patient was diagnosed as having aspergilloma in a pre-existing healed tubercular cavity and the second one with subacute necrotizing pulmonary aspergillosis, which simulated as bronchial carcinoma. BIRDEM Med J 2021; 11(3): 227-230

In learning, repeated experiences might be integrated individually as they occur, or they might b... more In learning, repeated experiences might be integrated individually as they occur, or they might be combined within dedicated time windows, possibly promoting quality control. Here we show that in Pavlovian, incremental and incidental learning, related information acquired within time windows of 5h (time units for learning) is combined to determine whether and what mice learn. Trials required for learning had to occur within 5h, when learning-related shared partial cues could produce association and interference with learning. Upon acquisition, cFos expression was elevated during 5h throughout specific system-wide neuronal assemblies. Time unit function depended on network activity and cFos expression. Local cFos activity was required for distant assembly recruitment through network activity and distant BDNF. Long-term consolidation of the memories depends on processes occurring many hours after acquisition. Whether this involves plasticity that is specifically required for long-term...

Journal of Power Sources, 2021

SummaryIndividual memories are often linked so that the recall of one triggers the recall of anot... more SummaryIndividual memories are often linked so that the recall of one triggers the recall of another. For example, contextual memories acquired close in time can be linked, and this is known to depend on temporary increase in excitability that drive the overlap between dorsal CA1 (dCA1) hippocampal ensembles encoding the linked memories. Here, we show that the Locus Coeruleus (LC) cells projecting to dCA1 have a key permissive role in contextual memory linking, without affecting contextual memory formation, and that this effect is mediated by dopamine and not by noradrenaline. Additionally, we found that LC to dCA1 projecting neurons modulate the excitability of dCA1 neurons, and the extent of overlap between dCA1 memory ensembles, as well as the stability of coactivity patterns within these ensembles. This discovery of a neuromodulatory system that specifically affects memory linking without affecting memory formation, reveals a fundamental separation between the brain mechanisms t...

Electrochimica Acta, 2021

Abstract Till date, magnetic field dependent variations in specific capacitance have only been re... more Abstract Till date, magnetic field dependent variations in specific capacitance have only been reported in simple binary oxides or alloys. Ternary spinels are often considered to be a composite of two or more mono-cationic entities, which allows them to deliver high specific capacitance. This paper deals with one such spinel i.e. NiCo2O4 (NCO), with 2-dimentional porous morphology, for obtaining highly responsive magnetic supercapacitors. Compared to the constituent oxides viz., NiO and Co3O4, NiCo2O4 shows nearly 100% higher response under magnetic field. Such results make this spinel furthermore useful for industrial applications. The results can be explained by the variation in dielectric constant, ESR, and ion diffusion as a function of applied magnetic fields. In such 2-dimentional porous oxides, a modified theoretical model has to be utilized to explain the magnetic field induced specific capacitance changes. There is a need to consider the impact of diffusion coefficient and additional convection term that is induced by the Fick's law. Another aspect, related with the carbon footprint for the materials, is determined using the life cycle assessment studies. This shows another advantage of using NiCo2O4 in energy storage devices.

The Journal of Physical Chemistry C, 2020

Recent results have shown that electrochemical energy storage devices can change their characteri... more Recent results have shown that electrochemical energy storage devices can change their characteristics near the magnetic field environment. Mostly, this change is attributed to the magnetically responsive electrode materials. It is still not expected that significant change can also be induced under a magnetic field by replacing nonmagnetic electrolytes. In this paper, it is clearly shown that this 'change' does occur and its magnitude can be as high as 50%. To date, a Nernstian relation across the electrode is used to explain the supercapacitive behavior of a cell, ignoring the contributions from the magnetic field, even if it is present in the surroundings of the device. Therefore, it is necessary to modify these well-established theoretical models to explain the magnetic field-dependent behavior in energy storage devices. It is shown that the Lorentz force plays a consequential role in inducing colossal changes in the specific capacitance of a supercapacitor. Seven different nonmagnetic electrolytes are combined with Fe 2 O 3 electrodes to prove the proposed concept. The modified theory leads to consistent results, which are corroborated with the experimental data.

Neuron, 2021

Memory formation is dynamic in nature, and acquisition of new information is often influenced by ... more Memory formation is dynamic in nature, and acquisition of new information is often influenced by previous experiences. Memories sharing certain attributes are known to interact so that retrieval of one increases the likelihood of retrieving the other, raising the possibility that related memories are organized into associative mnemonic structures of interconnected representations. Although the formation and retrieval of single memories have been studied extensively, very little is known about the brain mechanisms that organize and link related memories. Here we review studies that suggest the existence of mnemonic structures in humans and animal models. These studies suggest three main dimensions of experience that can serve to organize related memories: time, space, and perceptual/conceptual similarities. We propose potential molecular, cellular, and systems mechanisms that might support organization of memories according to these dimensions.

CrystEngComm, 2019

Comparative study of TMO based hollow and solid nanostructures for supercapacitor applications.

Nature Neuroscience, 2018

Nature Communications, 2019

Cold Spring Harbor Symposia on Quantitative Biology, 2019

Parvalbumin (PV) basket cells are widespread local interneurons that inhibit principal neurons an... more Parvalbumin (PV) basket cells are widespread local interneurons that inhibit principal neurons and each other through perisomatic boutons. They enhance network function and regulate local ensemble activities, particularly in the γ range. Organized network activity is critically important for long-term memory consolidation during a late time window 11-15 h after acquisition. Here, we discuss the role of learning-related plasticity in PV neurons for long-term memory consolidation. The plasticity can lead to enhanced (high-PV) or reduced (low-PV) expression of PV/GAD67. High-PV plasticity is induced upon definite reinforced learning in early-born PV basket cells, whereas low-PV plasticity is induced upon provisional reinforced learning in late-born PV basket cells. The plasticity is first detectable 6 h after acquisition, at the end of a time window for memory specification through experience, and is critically important 11-15 h after acquisition for enhanced network activity and longterm memory consolidation. High-and low-PV plasticity appear to regulate activity in distinct local networks of principal neurons and PV basket cells. These findings suggest how flexibility and stability in learning and memory might be implemented through parallel circuits and networks.

Frontiers in Materials, 2019

Single phase NaFePO 4 can works as economically viable cathode material for Na-systems similar to... more Single phase NaFePO 4 can works as economically viable cathode material for Na-systems similar to LiFePO 4-a material that led to the commercialization of Li-ion based energy systems. The reported microstructures of hollow NaFePO 4 particles, with porous walls, establish their advantages over solid morphologies. The hollow structures deliver stable electrochemical specific capacitance of 115 F g −1 in 2 M NaOH electrolyte, over a large number of cycles. This observation is directly attributed to the increased surface area, transport channels and redox sites, which become available in the porous-hollow particles. Hitherto unreported electrochemical performance under non-ambient environment is also discussed. In contrast to recently reported in Fe-based metal oxides, where significant change in specific capacitance has been reported as a function of magnetic field, it is observed that NaFePO 4 can protect itself and suppress modifications. More importantly, NaFePO 4 can work as an efficient electrode material in the temperature range RT to 65 • C, which makes it useful for automotive industry.

Asian Journal of Oncology, 2016

Introduction: Abdominal organs are usually involved in lymphoreticular malignancies (LRM), and th... more Introduction: Abdominal organs are usually involved in lymphoreticular malignancies (LRM), and the detection is crucial for Initial staging, determination of the location and extent of disease, and is the hallmark for the choice of treatment. At present, the established radiological technique for staging Hodgkin's disease is computed tomography (CT) and ultrasonography (USG) in our country. Objective: The objective of the study was to evaluate the pattern of abdominal organ involvement in childhood LRM by USG and CT and to analyze the findings. Methods: The study included 121 children with newly diagnosed childhood LRM who underwent real time USG and contrast enhanced CT scan. The records of the US and CT scanning were analyzed with respect to size, shape, margins, echogenicity/density pattern of various abdominal organs and lymph nodes to evaluate the extent and pattern of abdominal organ involvement by the disease process. Results: Out of 121 cases of LRM, US detected signific...