Publications by authors named "Rohit Chavan"

DC-SIGN, a C-type lectin receptor expressed on antigen presenting cells, is crucial for pathogen recognition and immune modulation. While most glycomimetic DC-SIGN ligands are mannose-based, fucose-based ligands offer enhanced selectivity, potentially reducing off-target effects. This study reports the stereoselective synthesis of aryl α-L-fucosides and their binding affinity for DC-SIGN.

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DC-SIGN, a C-type lectin receptor expressed on immune cells, is considered a promising target for immunomodulatory and antiviral therapies. While mannose-based glycomimetics have been extensively studied as DC-SIGN ligands, fucose-based strategies remain underexplored. This study explores the fucosylation of linear alcohols and sugars using eight different fucosyl donors, aiming at designing strategies for the development of fucose-based glycomimetics targeting DC-SIGN.

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Although metal halide perovskites are positioned as the most powerful light-harvesting materials for sustainable energy conversion, there is a need for a thorough understanding of molecular design principles that would guide better engineering of organic hole-transporting materials, which are vital for boosting the performance and stability of perovskite solar cells. To address this formidable challenge, here, we developed a new design strategy based on the curved N-doped polycyclic aromatic hydrocarbon merged with T-shaped phenazines being decorated with (phenyl)-di--methoxyphenylamine (OMeTAD)─N-PAH23/24 and -3,6-ditertbutyl carbazole (TBCz)─N-PAH25/26. As N-PAH23/24 exhibited satisfying thermal stability, the comparative studies performed with various experimental and simulation methods revealed a pronounced correlation between the depth of the central cyclazine core and the form of the T-shape units.

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The enhancement of the photovoltaic performance upon the aging process at particular environment is often observed in perovskite solar cells (PSCs), particularly for the devices with 2,2',7,7'-tetrakis(N,N-di(4-methoxyphenyl)amino)-9,9'-spirobifluorene (spiro-OMeTAD) as hole transporting material (HTM). In this work, for the first time the effect of aging the typical n-i-p PSCs employing nickel phthalocyanine (coded as Bis-PF-Ni) solely as dopant-free HTM is investigated and as an additive in spiro-OMeTAD solution. This study reveals that the prolong aging of these devices at dry air condition (RH = 2%, 25 °C) is beneficial for the improvement of their performances.

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Engineering multidimensional two-dimensional/three-dimensional (2D/3D) perovskite interfaces as light harvesters has recently emerged as a potential strategy to obtain a higher photovoltaic performance in perovskite solar cells (PSCs) with enhanced environmental stability. In this study, we utilized the 1,5-diammonium naphthalene iodide (NDAI) bulky organic spacer for interface modification in 3D perovskites for passivating the anionic iodide/uncoordinated Pb vacancies as well as facilitating charge carrier transfer by improving the energy band alignment at the perovskite/HTL interface. Consequently, the NDAI-treated 2D/3D PSCs showed an enhanced open-circuit voltage and fill factor with a remarkable power conversion efficiency (PCE) of 21.

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CsPbI is a promising material for optoelectronics owing to its thermal robustness and favorable bandgap. However, its fabrication is challenging because its photoactive phase is thermodynamically unstable at room temperature. Adding dimethylammonium (DMA) alleviates this instability and is currently understood to result in the formation of DMA Cs PbI perovskite solid solutions.

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Article Synopsis
  • - Recent advancements in 2D/3D perovskite heterostructures combine the high efficiency of 3D perovskites with the enhanced stability of 2D perovskites, focusing on a specific structure using ammonium thiocyanate (NHSCN) and xylylene diammonium iodide (XDAI).
  • - The NHSCN-treated 3D methylammonium lead triiodide (MAPbI) solar cells achieved a power conversion efficiency (PCE) of 19.6%, up from 17.18% in untreated versions, while the 2D/3D hybrid solar cells reached an impressive PCE of 20.74%.
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Circadian rhythms are self-sustained oscillators with a period of 24 h that is based on the output of transcriptional and post-translational feedback loops. Phosphorylation is considered one of the most important post-translational modifications affecting rhythmicity from cyanobacteria to mammals. For example, the lack of cyclin-dependent kinase 5 (CDK5) shortened the period length of the circadian oscillator in the Suprachiasmatic Nuclei (SCN) of mice via the destabilization of the PERIOD 2 (PER2) protein.

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Two-dimensional (2D) metal halide perovskites have recently emerged as promising photovoltaic materials due to their superior ambient stability and rich structural diversity. However, power conversion efficiencies (PCEs) of the 2D perovskites solar cells (PSCs) still lag behind their three-dimensional (3D) counterpart, particularly due to the anisotropy in the charge carrier mobility and inhomogeneous energy landscape. A promising alternative is Dion-Jacobson (D-J) phase quasi-2D perovskite, where the bulky organic diammonium cations are introduced into inorganic frameworks to remove the weak van der Waals interactions between interlayers and to improve the open-circuit voltage ().

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Daily recurring events can be predicted by animals based on their internal circadian timing system. However, independently from the suprachiasmatic nuclei (SCN), the central pacemaker of the circadian system in mammals, restriction of food access to a particular time of day elicits food anticipatory activity (FAA). This suggests an involvement of other central and/or peripheral clocks as well as metabolic signals in this behavior.

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Fullerene derivatives with a strong electron-accepting ability play a crucial role in enhancing both the performance and stability of perovskite solar cells (PSCs). However, most of the used fullerene molecules are based on [6,6]-phenyl-C-butyric acid methyl ester (PCBM), which limits the device performance due to difficulties in preparing high-quality and uniform thin films. Herein, solution-processable azahomofullerene (AHF) derivatives (abbreviated as AHF-1 and AHF-2) are reported as novel and effective electron-transport layers (ETLs) in p-i-n planar PSCs.

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Perovskite solar cells (PSCs) have experienced outstanding advances in power conversion efficiencies (PCEs) by employing new electron transport layers (ETLs), interface engineering, optimizing perovskite morphology, and improving charge collection efficiency. In this work, we study the role of a new ultrathin interface layer of titanium nitride (TiN) conformally deposited on a mesoporous TiO (mp-TiO) scaffold using the atomic layer deposition method. Our characterization results revealed that the presence of TiN at the ETL/perovskite interface improves the charge collection as well as reduces the interface recombination.

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Circadian oscillations emerge from transcriptional and post-translational feedback loops. An important step in generating rhythmicity is the translocation of clock components into the nucleus, which is regulated in many cases by kinases. In mammals, the kinase promoting the nuclear import of the key clock component Period 2 (PER2) is unknown.

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Glutamate is concentrated into synaptic vesicles (SV) by the vesicular glutamate transporters (VGLUT) 1 and 2. VGLUTs also harbor a Na+/Pi-transport activity when residing at the plasma membrane. Here we aimed to identify whether the diurnal switches of VGLUT1 parallels interactions with or modification of endocytic proteins.

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The circadian clock contributes to the timing of many body functions including metabolism and reproduction. The hepatokine fibroblast growth factor 21 (FGF21) is a critical metabolic regulator involved in modulation of fertility. Here we show that lack of the clock component REV-ERBα elevates FGF21 levels in liver and plasma.

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REV-ERBα (encoded by Nr1d1) is a nuclear receptor that is part of the circadian clock mechanism and regulates metabolism and inflammatory processes. The glucocorticoid receptor (GR, encoded by Nr3c1) influences similar processes, but is not part of the circadian clock, although glucocorticoid signaling affects resetting of the circadian clock in peripheral tissues. Because of their similar impact on physiological processes, we studied the interplay between these two nuclear receptors.

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The circadian system has endowed animals with the ability to anticipate recurring food availability at particular times of day. As daily food anticipation (FA) is independent of the suprachiasmatic nuclei, the central pacemaker of the circadian system, questions arise of where FA signals originate and what role components of the circadian clock might play. Here we show that liver-specific deletion of Per2 in mice abolishes FA, an effect that is rescued by viral overexpression of Per2 in the liver.

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Within the suprachiasmatic nucleus (SCN) of the hypothalamus, circadian timekeeping and resetting have been shown to be largely dependent on both membrane depolarization and intracellular second-messenger signaling. In both of these processes, voltage-gated calcium channels (VGCCs) mediate voltage-dependent calcium influx, which propagates neural impulses by stimulating vesicle fusion and instigates intracellular pathways resulting in clock gene expression. Through the cumulative actions of these processes, the phase of the internal clock is modified to match the light cycle of the external environment.

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A strong link between obesity and dopamine (DA) has been established by studies associating body weight status to variants of genes related to DA signalling. Human and animal studies investigating this relationship have so far focused mainly on the role of DA within the mesolimbic pathway. The aim of this study was to investigate potential DA receptor dysregulation in the brainstem, where these receptors play a potential role in meal termination, during high-fat high-sugar diet (HFHS) exposure.

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Serotonin-specific reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) are antidepressant drugs commonly used to treat a wide spectrum of mood disorders (Wong and Licinio, 2001). Although they have been clinically used for more than 50 years, the molecular and cellular basis for the action of SSRIs and SNRIs is not clear. Considering that the changes in gene expression involved in the action of antidepressant drugs on memory have not been identified, in this study we investigated the impact of chronic treatment with a SSRI (fluoxetine) and a SNRI (venlafaxine) on the mRNA expression of genes related to memory cascade in the mouse hippocampus, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), nitric oxide synthase 1 (NOS1), neurotrophic tyrosine kinase receptor type 2 (TrKB), mitogen-activated protein kinases (MAPK/ERK) and serotonin transporter (SERT).

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Background: The Fat mass and obesity gene (FTO) has been identified through genome wide association studies as an important genetic factor contributing to a higher body mass index (BMI). However, the molecular context in which this effect is mediated has yet to be determined. We investigated the potential molecular network for FTO by analyzing co-expression and protein-protein interaction databases, Coxpresdb and IntAct, as well as the functional coupling predicting multi-source database, FunCoup.

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Genome-wide association studies have shown a strong association of single-nucleotide polymorphisms (SNPs) in the near vicinity of the TMEM18 gene. The effects of the TMEM18-associated variants are more readily observed in children. TMEM18 encodes a 3TM protein, which locates to the nuclear membrane.

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Background: Spinal muscular atrophy (SMA type I, II and III) is an autosomal recessive neuromuscular disorder caused by mutations in the survival motor neuron gene (SMN1). SMN2 is a centromeric copy gene that has been characterized as a major modifier of SMA severity. SMA type I patients have one or two SMN2 copies while most SMA type II patients carry three SMN2 copies and SMA III patients have three or four SMN2 copies.

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