Indian Institute of Science Education and Research Kolkata
Recent publications
In this work, the aggregation-induced photoluminescence emission (AIPE) of three water-soluble heterobimetallic Ir-Pt complexes was reported with insight into their photophysical and electrochemical properties and imaging of bacterial cells. An alkyne appended Schiff's base L, bridges bis-cyclometalated iridium(III) and platinum(II) terpyridine centre. The Schiff's base (N-N fragment) serves as the ancillary ligand to the iridium(III) centre, while the alkynyl end is coordinated to platinum(II). The pH and ionic strength influence the aggregation kinetics of the alkynylplatinum(II) fragment, leading to metal-metal and π-π interactions with the emergence of a triplet metal-metal-to-ligand charge transfer (3MMLCT) emission. The excellent reversibility and photostability of aggregation-induced emission (AIE) of these aqua-friendly complexes were tested for their ability to sense and selectively image E. coli cells at various pH values.
Amino acids, the natural building blocks of life, are highly functional small molecules with chirality and important catalytic properties. Imparting the exquisite properties of amino acids into the macromolecules allows us to prepare unique, well-defined, biocompatible, functional, and tailorable materials. They exhibit stimuli responsiveness, tunable optical characteristics, enhanced thermal, mechanical, and biological properties with desired cell-materials interactions. Considering the salient features and diverse applications of side-chain amino acid-containing polymers, in this feature article, we present a concise highlight on the recent trends (2015–present) of the synthesis and utilization of pendant amino acid-based polymeric architectures. This article covers the synthesis of different classes of side-chain amino acid-derived polymeric architectures, and their recent utilization in drug and gene delivery, antibacterial activity, anti-fouling activity, heavy metal ion sensing, tissue engineering, etc. We hope that this study will provide a comprehensive outline of key aspects associated with the construction of functional ‘bio-inspired’ polymeric materials with desired characteristics, and their enhanced potential applications.
Hub-filament systems (HFSs) are potential sites of formation of star clusters and high mass stars. To understand the HFSs and to provide observational constraints on current theories that attempt to explain star formation globally, we report a study of the region associated with G326.27-0.49 using infrared data of dust continuum and newly obtained observations on molecular tracers using the APEX telescope. We use the spectroscopic observations to identify velocity-coherent structures (filaments and clumps) and study their properties at a resolution of 0.4 pc. The region contains two main velocity components: first component shows four filaments between −63 and −55 km s−1 forming a spiral structure converging in a hub, the second filamentary component at ∼−72 km s−1 harbors a massive young stellar object and possibly interacts with the hub. The clumps harbouring the three main YSOs in the region are massive (187–535 M⊙), have luminosities consistent with B-type stars, have central densities of ∼106 cm−3 and drive large outflows. Majority of the velocity-coherent clumps in the region show virial parameters between 2–7, which considering the detection of protostars implies collapse to be gradual. We conclude that the region consists of a network of filaments through which mass accretes (∼10−4 M⊙ yr−1) onto the hub. The hub and some of the ends of filaments appears to be undergoing collapse to form new stars. This study identifies a target region for future high resolution studies that would probe the link between the core and filament evolution.
This report describes the 2 nd edition of the Symposium on Artificial Intelligence and Law (SAIL) organized as a virtual event during June 6--9, 2022. The aim of SAIL is to bring together experts from the industry and the academia to discuss the scope and future of AI as applied to the legal domain. The symposium is also meant to foster collaborations between researchers of the following communities: Law, Artificial Intelligence, Data Mining, Information Retrieval, and Natural Language Processing. Eminent researchers working on AI and Law in both the academia and the industry were invited to deliver talks at this symposium. Date: 6--9 June, 2022. Website: https://sites.google.com/view/sail-2022/.
Post-transcriptional regulation of p53, by the microRNA miR-125b and the RNA-binding protein HuR, controls p53 expression under genotoxic stress. p53 mRNA translation is repressed by miR-125b, tightly regulating its basal level of expression. The repression is relieved upon DNA damage by a decrease in miR-125b level, contributing to pulsatile expression of p53. The pulse of p53, as also of HuR, in response to UV irradiation coincides with a time-dependent biphasic change in miR-125b level. We show that the cause for the decrease in miR-125b level immediately post DNA-damage is enhanced exosomal export mediated by HuR. The subsequent increase in miR-125b level is due to p53-mediated transcriptional upregulation and enhanced processing, demonstrating miR-125b as a transcriptional and processing target of p53. p53 activates the transcription of primary miR-125b RNA from a cryptic promoter in response to UV irradiation. Together, these regulatory processes constitute reciprocal feedback loops that determine the biphasic change in miR-125b level, ultimately contributing to the fine-tuned temporal regulation of p53 expression in response to genotoxic stress.
BACKGROUND The free anterolateral thigh (ALTP) and free medial sural artery perforator (MSAP) flaps are time tested donor for head and neck, and extremities defect reconstruction. Proponents of either flap have concluded each as workhorse flap in their large cohort studies. However, we could not find any literature comparing the donor morbidities, or recipient site outcomes of these flaps, objectively. METHODS Retrospective data, such as demographic details, flap characteristics and post operative course, from patients who underwent free thinned ALTP (25 patients) and MSAP flap (20 patients) were included. At follow-up, donor site morbidity and recipient site outcomes were assessed, using previously defined protocols. These were compared in-between the two groups. RESULTS Free thinned ALTP (tALTP) flap had significantly more pedicle length and vessel diameter and harvest time than free MSAP flap (p value<.00). The differences in incidence of hyperpigmentation, itching, hypertrophic scar, numbness, sensory impairment and cold intolerance at the donor site in-between the two groups, were not significant statistically. Scar at free MSAP donor site was considered a significant social stigma (p value=.005). Recipient site cosmetic outcome was comparable (p value=.86), measured using aesthetic numeric analogue. CONCLUSIONS The free tALTP flap is superior to free MSAP flap in terms of pedicle length, vessel diameter, donor site morbidity, while the latter takes lesser time for harvest.
Ovarian cancer persists to be the most lethal gynecological malignancy, demanding rigorous treatments involving radio-chemotherapy that trigger toxicity and consequently mortality among patients. An improved understanding of the disease progression may pioneer curative therapies. Mouse epithelial ovarian cancer cell lines, ID8 and ID8-VEGF (overexpressing VEGF) were intraperitoneally injected in C57BL/6 female mice to develop a Syngeneic Ovarian cancer mouse model. It was observed that ID8-VEGF cells were able to induce aggressive tumor growth in mice compared to ID8 cells. Furthermore, results of the current in vitro study comparing ID8 and ID8-VEGF demonstrated that highly tumorigenic ID8-VEGF had reduced gap junctional intercellular communication (GJIC) due to intracellular Connexin 43 (Cx43) expression. Additionally, ID8 cells with reduced tumorigenic capability expressed significant GJIC. Furthermore, loss of GJIC in ID8-VEGF cells induced shorter tunneling nanotube formations, while ID8 cells develops longer tunneling nanotube to maintain cellular crosstalk. The administration of a pharmacological drug 4-phenylbutyrate (4PBA) ensured the restoration of GJIC in both the ovarian cancer cell lines. Additionally, 4PBA treatment significantly inhibited the migration of ovarian cancer cell lines and tumor formation in ovarian cancer mice models. In summary, the 4PBA-mediated restoration of GJIC suppressed migration (in vitro) and tumorigenesis (in vivo) of ovarian cancer cells. The present study suggests that Cx43 assembled GJIC and its supportive signaling pathways are a prospective target for restricting ovarian cancer progression.
Superdense coding uses entanglement as a resource to communicate classical information efficiently through quantum channels. A superdense coding method is optimal when its capacity reaches Holevo bound. We show that for optimality, maximal entanglement is a necessity across the bipartition of Alice and Bob, but neither absolute nor genuine multipartite entanglement is required. Unlike the previous schemes, which can transmit either even or odd bits of information, we demonstrate a generalized dense coding protocol using the genuine multipartite entangled GHZ state to send arbitrary information bits. Expressed in the eigenbasis of different Pauli operators, GHZ state is characterized by a unique parity pattern which enables us to formulate a security checking technique to ensure absolute security of the protocol. We show this method is better applicable in a scenario, where the initial information is distributed among spatially separated parties. Finally, optimizing the number of qubit(s) sent to Bob, we construct a distributed dense coding method, which completely depicts absolutely secure quantum communication between many to one party.
Understanding the role of solvent in translating molecular anisotropy to supramolecular polymers is in the early stages. A solvent's influence on the strength of different noncovalent interactions can explain anisotropic growth in some cases, but its effect on cooperative processes, particularly in mixed solvents, remains obscure. We report the self-assembly of a series of chiral perylene bisimides in water-cosolvent mixtures, and the results highlight the fascinating influence of solvent-solute interactions on supramolecular anisotropy, both chiral and morphological. The initial assembly is agnostic to solvent composition, resulting in weakly chiral, spherical nanostructures. In an extremely narrow solvent composition range, the nanospheres transform into long, prominently chiral supramolecular polymers. Further, chirality can be fully reversed by changing the good (achiral) cosolvent. We elucidate how solvent modulates specific noncovalent interactions and governs the kinetics and thermodynamics of key processes, such as spontaneous phase segregation, secondary nucleation, and cooperative growth. In the context of supramolecular polymerization, our results encourage one to steer the focus away from the physical attributes of a solvent (polarity, phase diagram, etc.) and toward the complexities of solvent-solute interactions.
Animals are known to acquire and store information of their environment in order to enhance their performance in different tasks like foraging, migration and breeding. Having information regarding nesting sites would be particularly useful when they have to relocate. In the current study, we asked if having information of a new nest prior to or at the onset of relocation has a positive impact on the ability of ant colonies to relocate. We performed five sets of experiments on a ponerine ant species Diacamma indicum that recruits nestmates solely by tandem running. By analyzing data of 4756 unique ants across 61 colonies, we found that, access to information of the new nest for 1 day prior to the relocation did not give any significant advantage as compared to no prior information of the new nest. However, access to information for 7 days prior to relocation resulted in 50% increase in the number of tandem leaders and reduction of the transport time by an average of 49%. Our data on providing information at the onset of relocation indicates that introducing explorers to the new nest did not aid the process of relocation but when information of a new nest was self‐acquired, there was a reduction in discovery time by 50% and also in the transport time per unit distance for relocation into a new nest. Having information regarding only the surroundings and not the nest at the onset of a relocation did not give any significant advantages. Further, the manner in which work was organized during the relocation process was not significantly influenced by prior information across any of the treatments. Our findings suggest that information of new nest is important and when such information is self‐acquired at the onset of relocation or is available for a long enough duration, it has a positive influence in the process of relocation in this ant species. On performing elegantly designed experiments we show that prior information is used by Diacamma indicum colonies to enhance relocation efficiency only when it is available for 7 days or is self‐acquired by colony members at the start of relocation.
Stimuli-responsive cross-linked nanocarriers that can induce lysosomal cell death (LCD) via lysosomal membrane permeabilization (LMP) represent a new class of delivery platform and have attracted the attention of researchers in...
Small interfering RNA (siRNA) has become the cornerstone against undruggable targets and for managing metastatic breast cancer. However, an effective gene silencing approach is faced with a major challenge due to the delivery problem. In our present study, we have demonstrated efficient siRNA delivery, superior gene silencing, and inhibition of metastasis in triple-negative breast cancer cells (MDA-MB-231) using rod-shaped (aspect ratio: 4) multivalent peptide-functionalized gold nanoparticles and compared them to monovalent free peptide doses. Multivalency is a new concept in biology, and tuning the physical parameters of multivalent nanoparticles can enhance gene silencing and antitumor efficacy. We explored the effect of the multivalency of shape- and size-dependent peptide-functionalized gold nanoparticles in siRNA delivery. Our study demonstrates that peptide functionalization leads to reduced toxicity of the nanoparticles. Such designed peptide-functionalized nanorods also demonstrate antimetastatic efficacy in Notch1-silenced cells by preventing EMT progression in vitro. We have shown siRNA delivery in the hard-to-transfect primary cell line HUVEC and also demonstrated that the Notch1-silenced MDA-MB-231 cell line has failed to form nanobridge-mediated foci with the HUVEC in the co-culture of HUVEC and MDA-MB-231, which promote metastasis. This antimetastatic effect is further checked in a xenotransplant in vivo zebrafish model. In vivo studies also suggest that our designed nanoparticles mediated inhibition of micrometastasis due to silencing of the Notch1 gene. The outcome of our study highlights that the structure-activity relationship of multifunctional nanoparticles can be harnessed to modulate their biological activity.
The Upper Cretaceous (Maastrichtian) Lameta Formation is well-known for its osteological and oological remains of sauropods from the eastern and western parts of the Narmada Valley, central India. The newly documented ninety-two titanosaur clutches from Dhar District (Madhya Pradesh State, central India) add further to this extensive data. Previously parataxonomy of these titanosaur clutches was carried out with a few brief reports on palaeobiological and taphonomic aspects. The quantitative data collected from the new clutches (this study) opens avenues to additionally understand more about titanosaur palaeobiology and to qualitatively understand preservation and taphonomical aspects of their egg clutches. Herein, we document 256 eggs and three clutch patterns (viz. circular, combination, linear) that are assignable to six oospecies. The high oospecies diversity points to a possible high diversity in titanosaur taxa in the Indian sub-continent though it is not reflected in titanosaurid body fossils. All the macro- and micro-structures helped in understanding egg deformation and preservation from a taphonomic point of view. Additionally, a pathologic egg documented from the study area helped in understanding the reproductive biology of titanosaurs, such as the possibility of segmented oviduct and sequential laying of eggs by titanosaurs. In addition, we made an attempt to infer aspects such as egg burial, absence of parental care, colonial nesting behavior. All the egg clutches were observed within sandy limestone and calcareous sandstone lithologies that occur in scattered outcrops with rocks showing floating siliciclastic grains in a micritic groundmass. Further, the presence of ferruginous sandstone in the Jamniapura and Padlya regions (Dhar District, central India) is indicative of a possible alluvial/fluvial setting. The presence of grainy intraclastic fabric, alveolar-septal fabrics, brecciation and shrinkage cracks observed in the clutch-bearing rocks are indicative of a low energy-low gradient palustrine depositional condition in a fluvial/alluvial setting. Finally, we envisage that a few egg clutches of this area were laid close to lake/pond margins while most were laid away from the lake/pond margins, and thus, were hatched.
The editorial paints a brief history of the conference – Theoretical Chemistry Symposium, organized by eminent theoretical and computational chemists from India.
Metabolism of an organism underlies its phenotype, which depends on many factors, such as the genetic makeup, habitat, and stresses to which it is exposed. This is particularly important for the prokaryotes, which undergo significant vertical and horizontal gene transfers. In this study we have used the energy-intensive Aromatic Amino Acid (Tryptophan, Tyrosine and Phenylalanine, TTP) biosynthesis pathway, in a large number of prokaryotes, as a model system to query the different levels of organization of metabolism in the whole intracellular biochemical network, and to understand how perturbations, such as mutations, affects the metabolic flux through the pathway - in isolation and in the context of other pathways connected to it. Using an agglomerative approach involving complex network analysis and Flux Balance Analyses (FBA), of the Tryptophan, Tyrosine and Phenylalanine and other pathways connected to it, we identify several novel results. Using the reaction network analysis and Flux Balance Analyses of the Tryptophan, Tyrosine and Phenylalanine and the genome-scale reconstructed metabolic pathways, many common hubs between the connected networks and the whole genome network are identified. The results show that the connected pathway network can act as a proxy for the whole genome network in Prokaryotes. This systems level analysis also points towards designing functional smaller synthetic pathways based on the reaction network and Flux Balance Analyses analysis.
The Sun’s activity, which is associated with the solar magnetic cycle, creates a dynamic environment in space known as space weather. Severe space weather can disrupt space-based and Earth-based technologies. Slow decadal-scale variations on solar-cycle timescales are important for radiative forcing of the Earth’s atmosphere and impact satellite lifetimes and atmospheric dynamics. Predicting the solar magnetic cycle is therefore of critical importance for humanity. In this context, a novel development is the application of machine-learning algorithms for solar-cycle forecasting. Diverse approaches have been developed for this purpose; however, with no consensus across different techniques and physics-based approaches. Here, we first explore the performance of four different machine-learning algorithms – all of them belonging to a class called Recurrent Neural Networks (RNNs) – in predicting simulated sunspot cycles based on a widely studied, stochastically forced, nonlinear time-delay solar dynamo model. We conclude that the algorithm Echo State Network (ESN) performs the best, but predictability is limited to only one future sunspot cycle, in agreement with recent physical insights. Subsequently, we train the ESN algorithm and a modified version of it (MESN) with solar-cycle observations to forecast Cycles 22 – 25. We obtain accurate hindcasts for Solar Cycles 22 – 24. For Solar Cycle 25 the ESN algorithm forecasts a peak amplitude of 131 ± 14 sunspots around July 2024 and indicates a cycle length of approximately 10 years. The MESN forecasts a peak of 137 ± 2 sunspots around April 2024, with the same cycle length. Qualitatively, both forecasts indicate that Cycle 25 will be slightly stronger than Cycle 24 but weaker than Cycle 23. Our novel approach bridges physical model-based forecasts with machine-learning-based approaches, achieving consistency across these diverse techniques.
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1,886 members
Babu Sudhamalla
  • Department of Biological Sciences
Sumit Khanra
  • Department of Chemical Sciences
Sudip Manna
  • Department of Biological Sciences
Bipul Pal
  • Department of Physical Sciences
Amirul I Mallick
  • Department of Biological Sciences
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Haringhata, 741246, Kolkata, West Bengal, India
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Professor Sourav Pal
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