Publications

Structural importance, synthesis and application of 1,2,3-oxadiazines and 1,2,3-thiadiazines and their benzo-derivatives have been discussed in the present article. An elaborate spectral analysis of nocuolin A, a naturally occurring dihydrooxazine derivative from cyanobacteria, has been reported. Syntheses and reactions of benzothiadiazine 1,1-dioxide derivatives involving mainly directed o-metalation and cyclocondensation strategies have also been reported. Design, and synthesis of a camphor derived chiral organocatalyst, known as camphor sulphonylhydrazine (CaSH) and its application in enantioselective transformations have also been discussed. Finally, biological activity of nocuolin A and its derivatives, as potential antibacterial and anticancer agents along with anxiolytic property of few benzothiadiazine-1,1-dioxide analogues have also been described.

This manuscript describes the syntheses of pyridine appended triazole-based mono- and bisphosphines, [o-Ph2P(C6H4){1,2,3-N3C(Py)C(H)}] (2), [o-Br(C6H4){1,2,3-N3C(Py)C(PPh2)}] (3), [C6H5{1,2,3-N3C(Py)C(PPh2)}] (4), [Ph2P(C6H4){1,2,3-N3C(Py)C(PPh2)}] (5) and [3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N] (6), their palladium and platinum chemistry and catalytic applications. These ligands upon treatment with [M(COD)Cl2] (M = Pd or Pt) yielded complexes with different coordination modes, depending on the reaction conditions. Both κ2-P,N and κ2-P,P coordination modes were observed in many of the complexes indicating the ambidentate nature of these ligands. Monophosphine 2 in the presence of a base afforded rare fused-5,6-membered PCN pincer complexes [MCl{o-Ph2P(C6H4){1,2,3-N3C(Py)C(H)}}-κ3-P,C,N] (7, M = Pd; 8, M = Pt), whereas the reactions of 4 with [M(COD)Cl2] (M = Pd, Pt) produced κ2-P,N chelate complexes [MCl2{C6H5{1,2,3-N3C(Py)C(PPh2)}-κ2-P,N}] (9, M = Pd; 10, M = Pt). Similar reactions of 5 and 6 resulted in κ2-P,P chelate complexes [MCl2{{3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N}-κ2-P,P}] (11, M = Pd; 12, M = Pt) and [MCl2{3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N}-κ2-P,P}] (13, M = Pd; 14, M = Pt), respectively. The palladium(ii) complexes have shown excellent catalytic activity in the α-alkylation reaction of acetophenone derivatives.

The 6-membered aza-heterocycles, 1,2,4-oxadiazines and 1,2,4-thiadiazines, are valuable scaffolds due to the vast spectrum of medicinal properties they possess. These scaffolds exist in several drugs or drug-leads such as MK-8428, mS-11, BPDZ44, and IDRA21. These can be classified as 2H-, 4H- or 6H-isomers depending upon the position of double bonds in the ring. The sulfur in thiadiazines exists in different oxidation states, namely, SII, SIV and SVI, of which SVI (1,2,4-benzothiadiazine-1,1-dioxide) is the most common oxidation state. This article discusses various methods such as cycloaddition, rearrangement and CH functionalization for the synthesis of 1,2,4-oxadiazines and 1,2,4-thiadiazines and their biological properties.

Context: There are more than 100 pathogenic variants in CYP17A1 that have been identified in patients with 17α-hydroxylase/17,20-lyase deficiency (17OHD). Objective: We aimed to describe 46,XY patients with 17OHD from our center and review the literature. Methods: We retrospectively analyzed genetically proven index cases of 17OHD from our 46,XY disorders of sex development cohort and reviewed similar cases from the literature (n = 150). Based on the phenotype, 17OHD probands were classified into combined severe deficiency (n = 128) and combined partial deficiency (n = 16). Additionally, patients with the apparent isolated 17,20-lyase deficiency (n = 7, from 6 families) were noted. Residual enzyme activities with the observed mutant enzymes were divided in 2 categories as < 1% and ≥ 1%, each for hydroxylase and lyase. Results: We present 4 index cases of 46,XY 17OHD with a complete spectrum of undervirilization and 2 novel variants in CYP17A1. In the review, the combined severe deficiency was the most common form, with more frequent female sex of rearing, hypertension, hypokalemia, suppressed renin, higher plasma corticotropin, lower serum cortisol, and androgens. Immunoassay-measured serum aldosterone was frequently (68.2%) unsuppressed (>5 ng/dL). Elevated serum progesterone had high sensitivity for diagnosis of combined 17OHD, even in combined partial deficiency (83.3%). Among patients with clinical phenotype of combined severe deficiency, 11.5% had partial 17α-hydroxylase and complete 17,20-lyase deficiency (>1%/<1%) and had significantly higher serum cortisol than those with < 1%/<1% activity. Conclusion: We report the first monocentric case series of Asian Indian 46,XY patients with 17OHD. We propose that a phenotype of severe undervirilization with milder cortisol deficiency may represent a distinct subtype of combined severe 17OHD with residual 17α-hydroxylase activity but severe 17,20-lyase deficiency (>1%/<1%), which needs further validation.

Objectives: To describe Asian Indian patients with 17β hydroxysteroid dehydrogenase 3 (17βHSD3) deficiency and to perform a systematic review to determine the factors influencing gender role in 46,XY disorder of sex development (DSD) due to 17βHSD3 deficiency. Patients and Design: We present the phenotypic and genotypic data of 10 patients (9 probands and 1 affected family member) with 17βHSD3 deficiency from our 46,XY DSD cohort (N = 150; Western India) and a systematic review of 152 probands with genetically proven, index 17βHSD3 deficiency patients from the world literature to identify the determinants of gender role. Results: 17βHSD3 deficiency was the third most common (6%) cause of non-dysgenetic 46,XY DSD in our cohort. Five patients each had prepubertal (atypical genitalia) and pubertal (primary amenorrhoea) presentations. Six patients were initially reared as female of whom two (one each in prepubertal and pubertal age) changed their gender role. Ten pathogenic molecular variants (six novel) were observed. In the systematic review, initial male sex of rearing was uncommon (10.5%) and was associated with atypical genitalia, higher testosterone/androstenedione (T/A) ratio and Asian origin. Gender role change to male was seen in 10.3% of patients with initial female sex of rearing and was associated with Asian origin but unrelated to pubertal androgens or molecular variant severity. It has not been reported in patients of European origin. Conclusions: We report the first Indian case series of 17βHSD3 deficiency, the third most common cause of 46,XY DSD, with six novel molecular variants. Distinct geographical differences in the frequency of initial male sex of rearing and gender role change to male in those initially reared as females in 17βHSD3 deficiency were noted which needs further evaluation for the underlying molecular mechanisms.

The splitting of water into hydrogen and oxygen under visible light is an emerging phenomenon in green energy technology. Nevertheless, selecting an appropriate photocatalyst is rather significant to enhance hydrogen production on a large scale. In this context, organic photocatalysts have received considerable attention owing to their larger surface area, control in diffusion adsorption, nanostructures and electronic properties. Herein, we have developed five either free base or transition metalated porphyrin-napthalimide based donor-acceptor systems (PN1-PN5) and studied their morphology, electronic properties and catalytic behaviour. Detailed studies suggest that the Co(ii) substituent D-A system (PN2) displayed a well-aligned one-dimensional (1D) nanowire with high electrical conductivity promoting remarkable photocatalytic hydrogen production rate (18 mM g-1 h-1) when compared to that of porphyrin-based derivatives reported until now. Thus, these results propose to investigate diverse metalated π-conjugated materials as photocatalysts for hydrogen production.

2,2′-Bipyridine based bisphosphine [C5H3N{N(H)CH2PPh2}]2 (1) and its bischalcogenide derivatives [C5H3N{N(H)CH2P(E)Ph2}]2 (2, E = O; 3, E = S; 4, E = Se) were synthesized, and further reacted with BF3·Et2O/Et3N to form doubly B ← N fused compounds [C5H3N(BF2){NCH2P(E)Ph2}]2 (5, E = O; 6, E = S; 7, E = Se) in excellent yields. The influence of the P 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 E bonds on the electronic properties of the doubly B ← N fused systems and their structural features were investigated in detail, supported by extensive experimental and computational studies. Compound 6 exhibited a very high quantum yield of ϕ = 0.56 in CH2Cl2, whereas compound 7 showed a least quantum yield of ϕ = 0.003 in acetonitrile. Density functional theory (DFT) calculations demonstrated that the LUMO/HOMO of compounds 5-7 mostly delocalized over the entire π-conjugated frameworks. The involvement of P E bonds in the HOMO energy level of these compounds follows the order: P O < P S < P Se. Time-correlated single photon counting (TCSPC) experiments of compounds 5-7 revealed the singlet lifetime of 4.26 ns for 6, followed by 4.03 ns for 5 and a lowest value of 2.18 ns (τ1) and 0.47 ns (τ2) with a double decay profile for 7. Our findings provide important strategies for the design of highly effective B ← N bridged compounds and tuning their photophysical properties by oxidizing phosphorus with different chalcogens. Compounds 5 and 6 have been employed as green emitters (λem = 515 nm) in fluorescent organic light-emitting diodes (OLEDs). For compound 5, doped into the poly(9-vinylcarbazole) (PVK) matrix with 5 wt% doping concentration, nearly 90 Cd m−2 luminance with 0.022% external quantum efficiency (EQE) was achieved. The best performance was observed for compound 6 doped into PVK by 1 wt% having a maximum luminance of 350 Cd m−2 and a similar EQE value.

2D materials have a thickness-dependent optical bandgap in the visible to near-infrared wavelength range with carrier mobilities in the range of 1 to 1000 cm2 Vs–1, making them suitable for applications related to light emission and detection in the visible spectrum, photovoltaics, and optical communication. Furthermore, high mechanical strength makes them promising for flexible and wearable optoelectronic devices, and the ability to tailor heterostructure properties with precision and ease can help enhance optoelectronic performance substantially. Graphene and transition metal chalcogenides are the most studied 2D materials for optoelectronic applications. In this chapter we have described typical optoelectronic device architectures, operation mechanisms including the effect of mechanical strain on optoelectronic performance, characterization methodologies, and performance benchmarking for these materials. Conventional optoelectronic devices, such as photodetectors, photovoltaic cells, and light-emitting devices, and the integration of 2D optoelectronics with silicon photonic circuits have been discussed. From an emerging application perspective, the role of 2D materials in neuromorphic devices, biomimetic optical sensors, heterostructure superlattices, and optoelectronic memories has been presented. Finally, we conclude by describing key challenges in optoelectronic device design, processing, and characterization that need to be overcome for scalable and mature 2D optoelectronic technologies.

The requirement of an efficient energy storage device has become an exclusive requisite for technological and scientific innovations. In the present work, by using the 2D monolayer semiconductor-semiconductor and semiconductor-metal lateral interface structures as the model structure, we performed periodic DFT calculations to examine the possibility of 2D MoS2-MoSe2 and MoS2-NbS2 lateral heterostructures (LHS) as the electrodes of a battery. The MoS2-MoSe2 lateral interface is a semiconductor, whereas the MoS2-NbS2 lateral interface preserves metallic character. Besides, we found that Li/Na ion adsorption is more influential on the lateral heterostructure and is exothermic, with ultrafast diffusion, and is comparable to their monolayers. Meanwhile, the calculated open-circuit voltage is enormously low, like other widely investigated pristine 2D materials. The enhanced electrical conductivity, short diffusion distances, minutely low equilibrium voltage with good stability, large theoretical capacity and ultrahigh mechanical strength offered bare 2D TMDs lateral heterostructures as a potential candidate for LIBs/SIBs applications. This work broadens the possibility of applications based on 2D TMD-based semiconductor-semiconductor and semiconductor-metal lateral heterostructures. The lateral heterostructures can give an exciting new paradigm and offer exciting opportunities for potential applications in portable electronic devices.

3-Oxindolinyl-malononitrile participates as a 1,2-binucleophile in a highly regio- and stereoselective [3 + 2] annulation with 1,3-bielectrophilic nitroallylic acetates leading to spirocyclopentane-indolinones. The reaction takes place in the presence of DABCO in THF at room temperature and affords the multi-functional spirocyclic compounds possessing three chiral centers, including a spiro-chiral center in good to excellent yields and short reaction time. The key role of the malononitrile moiety in controlling the reactivity and selectivity has also been demonstrated. An SN2′-intramolecular Michael addition pathway is proposed for the [3 + 2] annulation based on DFT calculation results.

3-Aminoquinoline (3AQ) has been used as a fluorescent probe for preferential solvation in hexane-ethanol solvent mixtures. Results of the present experiment have been put into context by comparison with prior observations with 5-aminoquinoline (5AQ) as the probe. 3AQ exhibits a relatively small change of dipole moment ( "μ = 2.2 D) upon photoexcitation, compared to 5AQ ( "μ = 6.1D), which might appear to be a hindrance in the way of its use as a solvation probe. Indeed, the values of parameters like spectral shifts are smaller for the present experiment with 3AQ. At the smallest concentration of alcohol used, its local mole fraction around the probe is significantly lower than in the previous experiments with 5AQ. However, these apparent disadvantages are outweighed by the significant increase in fluorescence intensity and lifetime observed with increasing concentration of ethanol in the solvent mixture, as opposed to the drastic fluorescence quenching that occurs for 5AQ. This is a marked advantage in the use of 3AQ in studies like the present one. The local mole fraction of ethanol and preferential solvation index experienced by 3AQ are in line with those reported for 5AQ. The disadvantage of the smaller magnitude of "μ persists in the time resolved fluorescence experiments, for solvent mixtures with very low ethanol content. Negligible wavelength dependence of fluorescence transients of 3AQ is observed for x p = 0.002,. However, this effect is outweighed at higher alcohol concentrations, for which nanosecond dynamics of preferential solvation is observed.

This work focuses on developing a 3D progressive damage model (PDM) to predict drilling-induced damage and its effect on the load-carrying capacity of fiber reinforced plastics (FRP) laminates. The proposed PDM is based on 3D Hashin's failure criterion and a linear damage evolution law. It was implemented as a VUMAT subroutine in an Abaqus/explicitTM. Specifically, the model allows defining pre-existing damage through state-dependent variables. The PDM was first validated with a single element, mesh dependency, and open hole tension tests. Subsequently, it was applied to model drilling and drilling-induced damage. Single element tests verify primary damages. Further, open hole lamina in tension fails with matrix cracking along the fiber direction irrespective of their fiber orientation. Furthermore, in open hole [45/−45/90/45/0/−45/0/45/−45/0]S laminate in tension, 0° plies fail with fiber damage, whereas other plies fail with matrix damage. In drilling of a carbon fiber reinforced plastics (CFRP) laminate, the damage at the exit ply significantly increases with an increase in feed, while it slightly reduces with an increase in speed. The drilling-induced damage was then incorporated as pre-existing damage in the open hole laminate using cohesive interaction and state-dependent variables. The presence of the pre-existing drilling-induced damage has lowered the load-carrying capacity of the laminate by 8%. The predictions are in excellent agreement with experimental data from the literature.

We present a classification-based approach for the best next view selection and show how we can plausibly obtain a supervisory signal for this task. The proposed approach is end-to-end trainable and aims to get the best possible 3D reconstruction quality with an actively selected second view, given a passively chosen initial view. The proposed model consists of two stages: a classifier and a reconstructor network trained directly from ground truth voxels, as opposed to exhaustively selecting ground truth of best pair views. While testing, the proposed method assumes no prior knowledge of the underlying 3D shape for selecting the next best view. We demonstrate the proposed method's effectiveness via detailed experiments on synthetic and real images and show how it provides improved reconstruction quality than the existing state of the art 3D reconstruction and the next best view prediction techniques.

In the V-shaped title Schiff base, C41H50N2O4, the planes of the benzene rings of the central diphenylmethane unit make a dihedral angle of 70.40 (5)°, whereas the planes of the neighbouring benzene and ortho-vanilin rings are twisted with respect to one another by dihedral angles of 75.76 (5) and 73.89 (6)°. The Schiff base displays intramolecular O - HN hydrogen bonds and weak intermolecular C - HO contacts.

Engineered 3Dnanostructures have played a crucial role in the development of modern electronic devices. However, the demand for higher dimensional nanostructures have become a necessity for the development of superior next generation miniaturized devices. Traditional two-photon femtosecond laser-based fabrication techniques have enabled fabrication of 3D nanostructures. Carbon quantum dots have recently emerged as a new alternative for achieving subwavelength 3D optical lithography. Here, we report sensing of organo-arsenic(V) species at ppb levels using multimodal carbon quantum dots based 4D miniaturized ultrasensitive nanosensor and development of a device thereof using two-photon lithography. Manganese, nitrogen, and sulphur-doped carbon quantum dots have been used for development of this two-component, two-photon active functional resin for 3D printing of optically active 4D nanostructures. These have sub-wavelength resolved features, and are selectively sensitive to organo-arsenic species. The doped-carbon quantum dots initiate two-photon polymerization in the functional resin and induce emissive attributes to the polymerized nanostructures that impart selectivity towards dimethylarsinate ions (DAI) even at the ppb concentration levels. The miniaturized sensor strip shows a change in fluorescence of the nanostructures when subjected to the analyte. The emission intensities increases with increase in the concentration of DAI. The sensor can detect concentrations of the analyte as low as 1 ppb. This work opens new avenues to meet the demand for multi-dimensional nanostructures for development of superior next-generation of multifunctional miniaturized devices.

A Two stage on-board electric vehicle charger (OBEVC) has a front-end power factor correction (PFC) converter and a dc-dc converter to charge the main battery. In addition, there is an isolated dc-dc converter, typically one-third the rating of the main battery charger, to supply various auxiliary low voltage loads. In this paper, a new on-board charger consisting of fewer circuit components and having a higher power density compared to the converters reported in the literature, is proposed. This is achieved by completely eliminating the isolated low power dc-dc converter. In grid connected mode, Totempole PFC and dual active bridge (DAB) perform either grid to vehicle (G2V) or vehicle to grid (V2G) operation with main battery. In driving mode, an interleaved buck converter is formed using the first stage circuit (Totempole) components. The second leg of Totempole PFC is integrated with ripple power compensation (RPC) circuit to eliminate the second order ripple power in the dc link. It also serves as one of the phases for interleaved buck converter in driving mode. The DAB along with interleaved buck converter supply power to the auxiliary battery and low voltage loads. The operation of this converter is explained and detailed simulation studies on a 7.2 kW on-board charger are carried out.

This paper reports a flash-assisted time-interleaved SAR (FATI-SAR) ADC for digitizing the RF signal directly. The ADC provides the highest conversion speed per channel. In the proposed architecture, the key idea is to use the merged capacitor switching (MCS) technique to make energy efficient SAR ADC. An extra clock cycle is used to provide increased resolution without using power-consuming calibration circuits. The ADC is simulated in a 40nm standard digital CMOS process. It achieves 7.16 bit ENOB, 44.86 dB SINAD, 60.91 dBc SFDR at 2 GS/s with a Nyquist rate input signal. The power consumption is 20.5 mW from a 1.1 V supply, which corresponds to 71.67 fJ/conversion-step FoMw and 151.74 dB FoMs.

We show that there is a better-than-brute-force algorithm that, when given a small constant-depth Boolean circuit C made up of gates that compute constant-degree Polynomial Threshold functions or PTFs (i.e., Boolean functions that compute signs of constant-degree polynomials), counts the number of satisfying assignments to C in significantly better than brute-force time. Formally, for any constants d, k, there is an ε> 0 such that the zero-error randomized algorithm counts the number of satisfying assignments to a given depth-d circuit C made up of k-PTF gates such that C has at most n1+ε many wires. The algorithm runs in time 2n-nΩ(ε). Before our result, no algorithm for beating brute-force search was known for counting the number of satisfying assignments even for a single degree-k PTF (which is a depth-1 circuit with linearly many wires).We give two different algorithms for the case of a single PTF. The first uses a learning algorithm for learning degree-1 PTFs (or Linear Threshold Functions) using comparison queries due to Kane, Lovett and Moran (STOC 2018), and the second uses a proof of Hofmeister (COCOON 1996) for converting a degree-1 PTF to a depth-two threshold circuit with small weights. We show that both these ideas fit nicely into a memoization approach that yields the #SAT algorithms.

This paper presents the 38-GHz transmitter (Tx) and receiver (Rx) chips applied in Unmaned Aerial Vehicle. Unlike the works in [1], [3]-[5] using Phased-Array approaches, the presented Tx and Rx uses single channel approaches to save the power. The Tx can provide 15 dBm saturated power with 16 dB gain under 0.425W and the Rx can provide 5 dB Noise Figure with 25 dB conversion gain under 0.53 W. Both Tx chip can achieve EVM of 2.6% rms under 4096-QAM using AI modeling.

In this paper, a wideband, multiple-input-multiple-output (MIMO) antenna with good isolation based on the complementary antenna concept is proposed. The complementary antenna is based on a quarter-mode substrate integrated waveguide (QMSIW) and a 90-degree bent planar dipole, with the former acting as a magnetic dipole and the latter as an electric dipole. The proposed complementary antenna is fed coaxially. Good isolation between the antenna elements is obtained without any decoupling network throughout the operating bandwidth even though they are in electrical contact with each other. A fabricated prototype achieves a measured impedance bandwidth of 27.6%, an envelope correlation coefficient (ECC) of less than 0.004 and, stable gain higher than 4.8 dBi. The port to port isolation is higher than 18.7 dB, and 33.2 dB for adjacent antennas and diagonally opposite antennas, respectively, throughout the operating band. The effect of the substrate thickness on the bandwidth and the isolation is studied. It is observed that a bandwidth of 47% with good isolation is achieved for a substrate thickness of 3.8 mm.