BITS Faculty Publications

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1 3D-printed smart functional prototypes as sensors and actuators for robotic applications
(De Gruyter, 2024) Kala, Prateek
Soft robotics, inspired by nature, is a trending research area that is based on material science and the available mechanism (pneumatic, thermal, magnetic, electrostatic, etc.) to activate them. In the recent past, polylactic acid (PLA) has shown promising material characteristics, and researchers explored the 4D printing of PLA-based functional prototypes that can be used for high-strength biomedical applications for bovines. But hitherto, little has been explored about the sensing and actuation capabilities of PLA for implantable robotic applications in bovine. In this study, PLA extracted from biomedical waste has been used to prepare the functional prototypes (implants in bovine). Further, it has been primarily recycled by varying number of shredding cycles, and finally, feedstock filaments of the same have been prepared on the single screw extruder. For analyzing the sensing and actuation capabilities of the recycled material, the prototypes were fabricated on the fused deposition modeling setup using the following process parameters: raster angle, 45°; infill pattern, grid; printing speed, 40 mm/s; and infill density, 50%. Initially, the pressure-based sensor was designed in the high-frequency structure simulator simulation software and then tested on the vector network analyzer setup to observe the dielectric properties, that is, dielectric constant (ϵr) and loss tangent (tan δ) under the effect of pressure. Further, a hydrothermal actuator for robotic application has been programmed by mechanical force, and the shape recovery of the deformed prototype has been observed under the effect of hydrothermal stimuli. The change in dielectric properties (ϵr and tan δ) of the recycled material has been observed through the insertion loss (S21) versus resonant frequency (fr), which may be used for online health monitoring of patients through a Bluetooth device by observing the electromagnetic signal in the industrial, scientific, and medical (ISM) band.
1,2,3,4-Tetrahydroisoquinoline (THIQ) as privileged scaffold for anticancer de novo drug design
(Taylor & Francis, 2021-04) Murugesan, Sankaranarayanan
Cancer is a dreadful disorder that is emerging as one of the leading causes of mortality across the globe. The complex tumor environment, supplemented with drawbacks of the existing drugs, has made it a global health concern. The Tetrahydroisoquinoline (THIQ) ring holds an important position in medicinal chemistry due to its wide range of pharmacological properties. Several THIQ based natural products have been previously explored for their antitumor properties, making it a vital scaffold for anticancer drug design.
1,3,5-Trisubstituted benzenes as fluorescent photoaffinity probes for human carbonic anhydrase II capture
(RSC, 2013) Addy, Partha Sarathi
The ‘capture’ of proteins by small molecules via irreversible cross-linking mediated by photo-irradiation is of interest in the field of proteomics (for reviews see ref. 1). The technique has the potential for profiling protein-binding by small molecules, an objective of importance both for basic cell biology and in pharmaceutical science. Capture compounds, or photoaffinity probes, are typically endowed with three functions comprising (i) a selectivity function, such as an enzyme inhibitor, (ii) a photo-cross linking group (capture function) and (iii) a sorting group to enable separation of the captured protein from biological mixtures, such as biotin or an alkyne for subsequent modification. The captured protein(s) can be isolated using streptavidin beads and identified by mass spectrometry or Western blotting (for examples see ref. 2)
1,3-Carbon D–A strategy for [3 + 2] cycloadditions/annulations with imines: synthesis of functionalized pyrrolidines and related alkaloids
(RSC, 2014) Kumar, Indresh
Cycloaddition/annulation reactions remain the most attractive methods for the synthesis of five membered heterocyclic ring systems. Among the three possible strategies for [3 + 2] cycloaddition, this review focuses on 1,3-carbon donor–acceptor (C3, D–A) cycloaddition/annulation reactions with imines to synthesize pyrrolidines. The formal [3 + 2] cycloaddition, which includes the in situ 1,3-carbon D–A precursor generation through metal catalysis, Lewis acid catalysis and organocatalysis approaches is highlighted. The scope and limitations of this strategy along with its applications in the synthesis of natural product alkaloids reported during the last decade are outlined.
1-(m-Chlorophenyl)piperazine induces depressogenic-like behaviour in rodents by stimulating the neuronal 5-HT2A receptors: Proposal of a modified rodent antidepressant assay
(Elsevier, 2009-04) Mahesh, R.
1-(m-Chlorophenyl)piperazine (mCPP) has a fairly complex neuropsychopharmacological profile owing to its affinity to multiple serotonergic receptors. This investigation was designed to establish the effect of mCPP on rodent depression-like behaviour. mCPP was screened in a rodent behavioural test battery comprising of validated antidepressant assays and interaction studies with conventional antidepressants and ligands were carried out in forced swim and tail suspension test (in mice). mCPP (1 mg/kg, i.p.) exhibited depressant-like effects in forced swim and tail suspension test (in mice), without influencing the locomotor status. Potentiation of 5-hydroxytryptophan/pargyline induced head twitches (in mice) and hyperthermic effects (in rats) were observed at the same dose level. Further, the behavioural anomalies of the olfactory bulbectomised (OBX) rats were augmented by chronic mCPP (1–2 mg/kg) treatment as observed from the modified open field, elevated plus maze and social interaction paradigms. Interaction studies revealed that the mCPP induced depressant-like effects were reversed by ketanserin, escitalopram, amitriptyline, ziprasidone, venlafaxine pretreatments but not by bupropion, harmane, ondansetron, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and MK-801. In conclusion, this study provided ample evidence that the stimulation of 5-HT2A receptors underlies the depressogenic-like effect of mCPP. Finally, the mCPP induced depression-like behaviour in rodents is envisaged as a modified antidepressant assay to identify novel serotonergic antidepressants.
1-Butyl-3-methylimidazolium p-toluenesulfinate: a novel reagent for synthesis of sulfones and β-ketosulfones in ionic liquid
(Elsiever, 2011-10-12) Kumar, Anil
A novel task-specific ionic liquid, 1-butyl-3-methylimidazolium p-toluenesulfinate, [bmim][p-TolSO2] has been synthesized and used as a nucleophile for the reaction with alkyl bromides and phenacyl bromides to prepare sulfones and β-ketosulfones in excellent yields (80–93%) in [bmim][BF4] ionic liquid. The isolated yields of sulfones and β-ketosulfones were higher in [bmim][BF4] than other organic solvents at room temperature.
1-D TiO2 Nanorods Array-Based Parallel Electrode Sensor for Selective and Stable Detection of Organic Vapors
(IEEE, 2020-01) Hazra, Arnab; Gangopadhyay, Subhashis
A solid-state vapor sensor in parallel electrode configuration was fabricated by employing 1-D TiO 2 nanorods as a sensing layer. Highly ordered and oriented TiO 2 nanorods were synthesized on a Ti substrate by using hydrothermal method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were used to characterize the TiO 2 nanorods/Ti samples. The developed Au/TiO 2 nanorods/Ti type parallel electrodes sensor demonstrated the potential of integrated operations of both resistive and capacitive changes towards various concentrations (50-300 ppm) of volatile organic compounds (VOCs) like methanol, ethanol, 2-propanol, acetone and benzene at 50 °C. The resistive response magnitude of the sensor was found to be increased from 13 % to 87% while the capacitive response magnitude of the sensor was increased from 32 % to 200%, as methanol concentration was increased from 50 ppm to 300 ppm. However, the use of both modes enhances the selectivity performance of the sensor as the resistive mode exhibited better selectivity for a lower concentration of VOCs and the capacitive mode for higher concentration of VOCs. Moreover, the sensor showed a very good stability because of low operating temperature (50°C) as well as rutile (major) phase of TiO 2 nanorods.
1-Methyl-3-butylimidazolium Decatungstate in Ionic Liquid: An Efficient Catalyst for the Oxidation of Alcohols
(Thieme, 2005) Kumar, Anil
An excellent system for the selective oxidation of benzylic and secondary alcohols with hydrogen peroxide catalyzed by 1-methyl-3-butylimidazolium decatungstate in [bmim][BF4] ionic liquid is described. The catalytic system is reusable and products are obtained in excellent yield under environmentally benign conditions.
1/f Noise in Drain and Gate Current of MOSFETs With High-k Gate Stacks Publisher: IEEE PDF
(IEEE, 2009-06) Rao, V. Ramgopal
In this paper, we investigate the quality of MOSFET gate stacks where high- k materials are implemented as gate dielectrics. We evaluate both drain- and gate-current noises in order to obtain information about the defect content of the gate stack. We analyze how the overall quality of the gate stack depends on the kind of high- k material, on the interfacial layer thickness, on the kind of gate electrode material, on the strain engineering, and on the substrate type. This comprehensive study allows us to understand which issues need to be addressed in order to achieve improved quality of the gate stack from a 1/ f noise point of view.
100 nm channel length MNSFETs using a jet vapor deposited ultra-thin silicon nitride gate dielectric
(IEEE, 1999) Rao, V. Ramgopal
Metal-nitride-semiconductor (MNS) FETs with channel lengths down to 100 nm with a novel jet vapor deposited (JVD) SiN insulator as gate dielectric are fabricated and characterized for their electrical performance. By employing the charge pumping technique, the SiN interface quality and its effect on the transistor performance are evaluated. We show that, compared to conventional SiO/sub 2/ MOSFETs, the SiN devices show lower gate leakage current, competitive drain current drive and transconductance, good interface quality, and reduced hot-carrier degradation.
100 year anniversary Measurement Science and Technology logo. Purpose-led Publishing logo. A reverse electrochemical floating-layer technique of SPM tip preparation
(IOP, 2000) Gangopadhyay, Subhashis
An experimental set-up involving a combination of reverse electrochemical etching and the floating-layer technique of tip preparation is presented. In the model only dc bias is used, avoiding the shortcomings of ac bias. The collection of two tips in a single etching process and mechanical auto-breaking of the circuit are emphasized. This cost and time effective, easy in-laboratory approach yields two sharp tips without paying attention to switching off the circuit. The nature of the tip shape arising from the floating-layer technique has been explained in terms of the electrical field distribution between the electrodes. The addition of some new information together with a few established facts will enrich and enlighten the art of tip preparation.
A 12.11 mW, 99 pJ/Conv.-Step SAR ADC with Optimal Power Efficiency for IoT
(IEEE, 2024-12) Gupta, Anu; Shekhar, Chandra
This brief presents a capacitive charge scaling DAC architecture with a two-phase non-overlapping clocking scheme to make an energy-efficient Successive Approximation Register (SAR) data converter for Internet-of-Things (IoT) applications. The proposed architecture comprises a Track & Hold (T/H), a Modified Strong Arm Latch comparator (MSAL), a SAR Control logic, and a digital-to-analog (D/A) converter. The proposed work is simulated using Cadence Virtuoso in TSMC 180 nm and achieves a minimum sampling rate of 1 MS/s and power consumption of 12.11 mW. To address the effects of process variations and mismatches on ADC performance, this paper conducts a thorough 500-point Monte Carlo (MC) simulation of the proposed SAR ADC circuit. The measured results show a Signal-to-Noise Ratio (SNR) of 47.81 dB, a Spurious-Free Dynamic Range (SFDR) of 54.32 dB, and ENOB of 7.65 Bits.
14 Ultrathin films of nanomaterials: a lyotropic liquid crystalline system and its sensing application
(De Gruyter, 2021) Gupta, Raj Kumar; Manjuladevi, V.
The ultrathin films of nanomaterials provide remarkable features that can be potentially employed for efficient device fabrication. In this chapter, an overview of ultrathin films of nanomaterials at different interfaces, along with their sensing capabilities, is discussed. From the symmetry point of view, the ultrathin films and sensing applications of the nanoparticles with spherical geometry (eg amphiphilic gold and TiO2 nanoparticle), one-dimensional system (single-walled carbon nanotube) and two-dimensional systems (functionalized graphene) are highlighted.
14K prolactin derived 14-mer antiangiogenic peptide targets bradykinin-/nitric oxide-cGMP-dependent angiogenesis
(FEBS Press, 2024-09) Majumder, Syamantak
Over the past few decades, VEGF-targeted antiangiogenic therapy for cancers has gained increasing attention. Nevertheless, there are still several limitations such as the potential resistance mechanisms arising in cancer cells against these therapies and their potential adverse effects. These limitations highlight the need for novel anti-angiogenesis molecules and better understanding of the mechanisms of tumor angiogenesis. In the present study, we investigated the antiangiogenic properties of a novel 14-mer antiangiogenic peptide (14-MAP) derived from N-terminal 14 kDa buffalo prolactin and characterized its mode of action. 14-MAP at the picomolar concentration inhibited VEGF- and bradykinin (an autacoid peptide expressed in vascular tissues in pathophysiology, BK)-stimulated endothelial nitric oxide (eNO) production, cell migration, and proliferation in endothelial cells and vessel development in the chick embryo. Although this peptide inhibited both VEGF- and BK-dependent angiogenic processes, its action was more pronounced in the latter. Moreover, the interference of 14-MAP with the eNO synthase (eNOS)-cyclic GMP pathway was also identified. A combination of a low dose of Avastin, a widely used drug targeting VEGF-dependent angiogenesis, and 14-MAP significantly reduced tumor size in an in vivo model of human colon cancer. Taken together, our results suggest that 14-MAP, a BK- and eNOS-dependent antiangiogenic peptide, might be useful for overcoming the limitation of VEGF-targeted antiangiogenic therapy in cancer patients. However, further studies will be required to further characterize its mode of action and therapeutic potential.
A 1D thiocyanato bridge nickel(II) system: crystal structure and magnetic property
(Elsiever, 2001-04) Laskar, Inamur Rahaman
A one-dimensional coordination polymer of nickel(II), [(μN,S-NCS)2{Ni(ampy)}]n (ampy=1-(2-aminoethyl)pyrrolidine) has been synthesized and characterized by X-ray single crystal analysis. Structure analysis reveals that each nickel(II) center is coordinated in a distorted octahedral fashion with four bridging thiocyanato ligands and one mesocyclic diamine ligand. The low temperature (300–18 K) magnetic measurement shows that the system is ferromagnetically coupled. The magnetic data are fitted to the de Neef equation, giving the parameters J=1.4 cm−1 and g=2.08.
1O2 Mediated Conversion of β-Enaminonitriles to α-Keto Amides Photosensitized by Recyclable H2TPP in Visible Light
(ACS, 2024-03) Grover, Nitika
We report a one-step approach for the conversion of β-enaminonitriles to synthetically versatile α-keto amides in moderate to high yields under visible light irradiation photosensitized by porphyrins. The method is mild, cost-effective, and sustainable and requires air as the sole reagent/oxidant. The reaction is believed to proceed via an ene-type pathway initiated by 1O2, followed by dehydration, imine hydrolysis, and subsequent nucleophilic substitution of the cyanide group by amine. The method offers a broad substrate scope and has also been extended for synthesis of α-keto esters with aliphatic alcohols as nucleophiles. The porphyrin recovered after the reaction can be reused multiple times.
2 - Signaling cross talk between biotic and abiotic stress responses in soybean
(Academic Press, 2016) Sharma, Rita
Biotic and abiotic stresses take a heavy toll on crop productivity in soybean (Glycine max (L.) Merr.). To deal with this problem, considerable efforts have been made to understand the molecular mechanism underlying stress perception and tolerance in response to both biotic and abiotic stresses. Recent advances have highlighted several candidate genes that are involved in tolerance to more than one type of stress and, therefore, affect the outcome of the stress response. In this chapter, we summarize the current knowledge about the key transcription factors and signaling components known to regulate stress cross talk in soybean. In total, twenty genes have been demonstrated to confer tolerance to multiple stresses using transgenic approaches. However, to date, only three genes including GmERF3, GmERF057, and GmCAM4 are known to confer tolerance to both biotic and abiotic stresses. Further, in addition to the key genes, the potential of microRNAs and mycorrhiza in engineering broad spectrum stress-tolerant soybean varieties has been discussed.
2, 2-Bis (hydroxymethyl) propionic acid based cyclic carbonate monomers and their (co) polymers as advanced materials for biomedical applications
(Elsevier, 2021-08) Chitkara, Deepak; Mittal, Anupama
Designing grafted biodegradable polymers with tailored multi-functional properties is one of the most researched fields with extensive biomedical applications. Among many biodegradable polymers, polycarbonates have gained much attention due to their ease of synthesis, high drug loading, and excellent biocompatibility profiles. Among various monomers, 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) derived cyclic carbonate monomers have been extensively explored in terms of their synthesis as well as their polymerization. Since the late 90s, significant advancements have been made in the design of bis-MPA derived cyclic carbonate monomers as well as in their reaction schemes. Currently, bis-MPA derived polycarbonates have taken a form of an entire platform with a multitude of applications, the latest being in the field of nanotechnology, targeted drug, and nucleic acid delivery. The present review outlines an up to date developments that have taken place in the last two decades in the design, synthesis, and biomedical applications of bis-MPA derived cyclic carbonates and their (co)polymers
2-(3'-Indolyl)-N-arylthiazole-4-carboxamides: Synthesis and evaluation of antibacterial and anticancer activities
(Elsiever, 2015-10) Kumar, Dalip; Kumar, Anil
A new series of 2-(3′-indolyl)-N-arylthiazole-4-carboxamides 17a–p has been designed and synthesized. Initial reaction of readily available thioamides 15 with bromopyruvic acid under refluxing conditions produced different thiazole carboxylic acids 16 which upon coupling with arylamines by using EDCI·HCl and HOBt afforded diverse arylthiazole-4-carboxamides 17a–p in 78–87% yields. Antibacterial activity evaluation against Gram-positive and Gram-negative bacterial strains led to compounds 17i–k and 17o as potent and selectively (Gram-negative) antibacterial agents. The cytotoxicity of thiazole carboxamides 17a–p was also evaluated on a panel of human cancer cell lines. Among the tested derivatives, compounds 17i (IC50 = 8.64 μM; HEK293T) and 17l (IC50 = 3.41 μM; HeLa) were identified as the most potent analogues of the series. Preliminary mechanism of action studies of thiazole carboxamide 17i suggested that its cytotoxicity against HeLa cells involves the induction of cell death by apoptosis.
2-(4-substituted piperazin-1-yl)-1,8-naphthyridine-3-carboxylic acids: Novel 5-HT3 receptor antagonists with anxiolytic-like activity in rodent behavioral models
(Candian Journal, 2013-06) Mahesh, R.
The aim of this study was to investigate the anxiolytic potential of a series of novel carboxylic acid based 1,8 naphthyridines as 5-HT3 receptor antagonists. The pA2 values of all the compounds were determined against agonist 2-methyl-5-hydroxytryptamine in longitudinal muscle myenteric plexus preparations from guinea pig ileum. Compounds with higher pA2 values, particularly those greater than ondansetron, a standard 5-HT3 receptor antagonist, and optimal log P values were screened in mice by using behavioral tests such as a light–dark (L/D) aversion test, elevated plus maze (EPM) test, and an open field test (OFT). In the L/D test, compounds 7a, 7b, 7d, 7e, and 7i (2 mg/kg body mass, intraperitoneal) significantly (P < 0.05) increased the latency time to leave the light compartment, total time spent in the light compartment, and the number of transitions between the light and dark compartments. Compounds 7a, 7d, 7f, 7h, and 7i (2 mg/kg, i.p.) significantly (P < 0.05) increased the time spent in the open arms and the number of entries into the open arms in the EPM test. In addition, compounds 7a, 7d, 7e, 7f, and 7h (2 mg/kg, i.p.) significantly (P < 0.05) increased the ambulation scores and the frequency of rearing in the OFT.