Siddhartha Sankar Ghosh

Indian Institute of Technology Guwahati

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Arun Chattopadhyay

Indian Institute of Technology Guwahati

P. Bhattacharya

National Institute of Pharmaceutical Education and Research

Amaresh Kumar Sahoo

Indian Institute of Information Technology Allahabad

Pallab Sanpui

Synergy University Dubai

Shobha Ghosh

Virginia Commonwealth University Medical Center

Deepanjalee Dutta

University of Bremen

Upashi Goswami

Indian Institute of Science Bangalore

Anumita Paul

Indian Institute of Technology Guwahati

Amit Jaiswal

Indian Institute of Technology Mandi

Subhamoy Banerjee

University of Engineering & Management

Cooperative Institutions

Indian Institute of Technology Guwahati

114

NSF National Center for Atmospheric Research

University of Engineering & Management

University of Michigan–Ann Arbor

Jadavpur University

National University of Singapore

Albert Einstein College of Medicine

Cornell University

University of Calcutta

University of Florida

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CESM1(WACCM) Stratospheric Aerosol Geoengineering Large Ensemble Project

Bulletin of the American Meteorological Society (2018)

Simone Tilmes Jadwiga H. Richter Ben Kravitz Douglas G. MacMartin Michael Mills

This paper describes the Stratospheric Aerosol Geoengineering Large Ensemble (GLENS) project, which promotes the use of a unique model dataset, performed with the Community Earth System Model, with the Whole Atmosphere Community Climate Model as its atmospheric component [CESM1(WACCM)], to investigate global and regional impacts of geoengineering. The performed simulations were designed to achieve multiple simultaneous climate goals, by strategically placing sulfur injections at four different locations in the stratosphere, unlike many earlier studies that targeted globally averaged surface temperature by placing injections in regions at or around the equator. This advanced approach reduces some of the previously found adverse effects of stratospheric aerosol geoengineering, including uneven cooling between the poles and the equator and shifts in tropical precipitation. The 20-member ensemble increases the ability to distinguish between forced changes and changes due to climate variability in global and regional climate variables in the coupled atmosphere, land, sea ice, and ocean system. We invite the broader community to perform in-depth analyses of climate-related impacts and to identify processes that lead to changes in the climate system as the result of a strategic application of stratospheric aerosol geoengineering.

Geoengineering

Earth system science

10.1175/bams-d-17-0267.1

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Citations (259)

Role of Interaction between Magnetic Rossby Waves and Tachocline Differential Rotation in Producing Solar Seasons

The Astrophysical Journal (2018)

Mausumi Dikpati Scott W. McIntosh G. D. Bothun P. S. Cally Siddhartha Sankar Ghosh

Abstract We present a nonlinear magnetohydrodynamic shallow-water model for the solar tachocline (MHD-SWT) that generates quasi-periodic tachocline nonlinear oscillations (TNOs) that can be identified with the recently discovered solar “seasons.” We discuss the properties of the hydrodynamic and magnetohydrodynamic Rossby waves that interact with the differential rotation and toroidal fields to sustain these oscillations, which occur due to back-and-forth energy exchanges among potential, kinetic, and magnetic energies. We perform model simulations for a few years, for selected example cases, in both hydrodynamic and magnetohydrodynamic regimes and show that the TNOs are robust features of the MHD-SWT model, occurring with periods of 2–20 months. We find that in certain cases multiple unstable shallow-water modes govern the dynamics, and TNO periods vary with time. In hydrodynamically governed TNOs, the energy exchange mechanism is simple, occurring between the Rossby waves and differential rotation. But in MHD cases, energy exchange becomes much more complex, involving energy flow among six energy reservoirs by means of eight different energy conversion processes. For toroidal magnetic bands of 5 and 35 kG peak amplitudes, both placed at 45° latitude and oppositely directed in north and south hemispheres, we show that the energy transfers responsible for TNO, as well as westward phase propagation, are evident in synoptic maps of the flow, magnetic field, and tachocline top-surface deformations. Nonlinear mode–mode interaction is particularly dramatic in the strong-field case. We also find that the TNO period increases with a decrease in rotation rate, implying that the younger Sun had more frequent seasons.

Tachocline

Helioseismology

Solar rotation

10.3847/1538-4357/aaa70d

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Citations (73)

Combination Therapy with MAPK-Pathway-Specific Inhibitor and Folic-Acid-Receptor-Targeted Selenium Nanoparticles Induces Synergistic Antiproliferative Response in BRAF Mutant Cancer Cells

ACS Biomaterials Science & Engineering (2019)

Anil P. Bidkar Pallab Sanpui Siddhartha Sankar Ghosh

Combination chemotherapy, where drugs with a nonoverlapping mode of action achieve better efficacy at lower doses with reduced dose-dependent side effects, holds promise for complete remission of the tumor. Herein, we report a combination therapeutic module comprised of the folic acid receptor (FAR)-targeted SeNPs (FA-SeNPs) and MAPK-pathway inhibitor PD98059 (PD98). While aberrant signaling leading to an uncontrolled proliferation in BRAF mutation bearing cancer cells including MDAMB231 (breast cancer) and A375 (melanoma) cells was inhibited by PD98, high expression of FAR by these cells also led to selective internalization of FA-SeNPs. Consequently, the combination treatment of PD98 and FA-SeNPs demonstrated synergistic antiproliferative efficacy in MDAMB231 and A375 cells involving apoptotic modes of cell death. The selective nature of the present combination module was supported by the low off-target response in L132 noncancerous lung cells. Moreover, the size of the three-dimensional MDAMB231 spheroids was successfully reduced because of the combination therapy projecting its potential in eradicating tumors in vivo.

Combination therapy

Folate receptor

10.1021/acsbiomaterials.9b00112

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Engineered Hybrid Nanosystem for Homologous Targeting of EMT Induced Triple Negative Breast Cancer Cells

ACS Applied Bio Materials (2023)

Muktashree Saha Siddhartha Sankar Ghosh

The increased mortality rate due to metastatic breast cancer with poor prognosis has raised concern over its effective therapy. Though various therapies and anticancer drugs have been approved, there is still a lack in the targeting of metastatic triple negative breast cancer (TNBC). We have developed a hybrid nanosystem that was synthesized by fusing exosomes from MCF-7 cells and nanovesicles from the MDA MB-231 cells that would be targeted. The developed nanosystem was characterized by various techniques like Western blotting, AFM, FETEM, DLS, CD, and fluorescence spectroscopy. The hybrid system was used for the delivery of an HDAC inhibitor, Trichostatin A (TSA), in combination with lapatinib (a tyrosine kinase inhibitor) for cotherapy of epithelial to mesenchymal transition (EMT) induced TNBC. This targeted cotherapy module had higher efficiency and effectivity in the reduction of metastatic ability and proliferation of EMT induced MDA MB-231 cells as compared to free inhibitor treatment or untargeted cotherapy. Reduction in the expression of the Wnt/β-catenin signaling pathway molecules like β-catenin (by 0.7 fold), Gsk3β (by 0.6 fold), and pGsk-3β (0.3 fold) was observed upon treatment. This subsequently resulted in the suppression of EMT markers, thereby resulting in reversing EMT to MET and suppressing metastatic breast cancer.

Triple-negative breast cancer

Targeted Therapy

Lapatinib

10.1021/acsabm.2c00925

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Genetic lesions of bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (UGT1A1) causing Crigler-Najjar and Gilbert syndromes: Correlation of genotype to phenotype

Human Mutation (2000)

Ajit Kadakol Siddhartha Sankar Ghosh Baljit S. Sappal Girish Sharma Jayanta Roy Chowdhury

Uridine-diphosphoglucuronate glucuronosyltransferases (UGTs) are a family of enzymes that conjugate various endogenous and exogenous compounds with glucuronic acid and facilitate their excretion in the bile. Bilirubin-UGT(1) (UGT1A1) is the only isoform that significantly contributes to the conjugation of bilirubin. Lesions in the gene encoding bilirubin-UGT(1), lead to complete or partial inactivation of the enzyme causing the rare autosomal recessively inherited conditions, Crigler-Najjar syndrome type-1 (CN-1) and type 2 (CN-2), respectively. Inactivation of the enzyme leads to accumulation of unconjugated bilirubin in the serum. Severe hyperbilirubinemia seen in CN-1 can cause bilirubin encephalopathy (kernicterus). Kernicterus can be fatal or may leave behind permanent neurological sequelae. Here, we have compiled more than 50 genetic lesions of UGT1A1 that cause CN-1 (including 9 novel mutations) or CN-2 (including 3 novel mutations) and have presented a correlation of structure to function of UGT1A1. In contrast to Crigler-Najjar syndromes, Gilbert syndrome is a common inherited condition characterized by mild hyperbilirubinemia. An insertional mutation of the TATAA element upstream to UGT1A1 results in a reduced level of expression of the gene. Homozygosity for the variant promoter is required for Gilbert syndrome, but not sufficient for manifestation of hyperbilirubinemia, which is partly dependent on the rate of bilirubin production. Several structural mutations of UGT1A1, for example, a G71R substitution, have been reported to cause mild reduction of UGT activity toward bilirubin, resulting in mild hyperbilirubinemia, consistent with Gilbert syndrome. When the normal allele of a heterozygote carrier for a Crigler-Najjar type structural mutation contains a Gilbert type promoter, intermediate levels of hyperbilirubinemia, consistent with the diagnosis of CN-2, may be observed.

Kernicterus

Glucuronosyltransferase

Unconjugated hyperbilirubinemia

Compound heterozygosity

10.1002/1098-1004(200010)16:4<297::aid-humu2>3.0.co;2-z

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Citations (384)

Rapid and label-free bacteria detection using a hybrid tri-layer dielectric integrated n-type organic field effect transistor

Journal of Materials Chemistry A (2019)

Anamika Dey Ashish Singh Deepanjalee Dutta Siddhartha Sankar Ghosh Parameswar Krishnan Iyer

An ultra-low voltage operated n-type OFET device that could detect and distinguish live bacteria with an LOD of 10³ cfu mL⁻¹ is developed.

Organic field-effect transistor

10.1039/c9ta06359e

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Citations (27)

Studying in vitro phagocytosis of apoptotic cancer cells by recombinant GMCSF-treated RAW 264.7 macrophages

International Journal of Biological Macromolecules (2017)

Vanitha Selvarajan Anil P. Bidkar Rajib Shome Aditi Banerjee Nidhi Chaubey

Viability assay

10.1016/j.ijbiomac.2017.05.003

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Citations (3)

Evaporation-Induced Patterns from Droplets Containing Motile and Nonmotile Bacteria

Langmuir (2007)

Tittu Thomas Nellimoottil Pinjala Nagaraju Rao Siddhartha Sankar Ghosh Arun Chattopadhyay

In this letter, we report the observations of specific pattern formation from the evaporation of aqueous droplets containing motile and nonmotile bacteria. We found that when motile bacteria were present the droplet evaporated into disclike patterned deposits of bacteria. However, when the bacteria were made nonmotile by treatment with liquid nitrogen, the droplet evaporated into ringlike deposits. We also observed that bacteria with higher motility produced more uniformly deposited disclike patterns. Furthermore, we propose a model with numerical simulations to explain the mechanism of formation of these patterns. The model is based on the advective fluid flow from the center of the droplet toward the edge due to enhanced evaporation from the edge of the pinned droplet in comparison to that from the free surface. For the case of motile bacteria, we have added another velocity parameter toward the axis of the droplet and directed against the fluid flow in order to account for the disclike pattern formation. The numerical simulations match the experimental observations well. The present work, by qualitative and quantitative understanding of the evaporation of bacteria droplets, demonstrates that the inherent bacterial motility is primarily responsible for the formation of these differential patterns.

10.1021/la7006205

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Citations (50)

CCDC 2102095: Experimental Crystal Structure Determination

The Cambridge Structural Database (2022)

Santa Mondal Shilpi Sarkar Siddhartha Sankar Ghosh Abu T. Khan

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

10.5517/ccdc.csd.cc28kdjs

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Citations (0)

Low frequency noise spectroscopy in InAs/GaAs resonant tunneling quantum dot infrared photodetectors

Microelectronics Journal (2007)

R. A. Rupani Siddhartha Sankar Ghosh Xiaohua Su P. Bhattacharya

We have studied the temperature dependence of low-frequency noise in InAs-GaAs resonant tunneling quantum dot infrared photodetectors (T-QDIPs). The noise in these devices has been investigated in the temperature range of 78-300K. The noise spectrum showed a weak Lorentzian component superimposed upon the 1/fγ spectrum. The change in the cut-off frequency of the Lorentzian was analyzed as a function of temperature. The activation energy of the trap associated with this Lorentzian was obtained as 0.155eV, which is in good agreement with the energy of the lowest energy state in the quantum dot.

10.1016/j.mejo.2007.07.108

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Citations (9)