Indian Institute of Science Education and Research Kolkata

Long‐lived triplet excitons are kingmakers to generate high efficiency optoelectronic OLEDs. However, it is difficult to produce matrix‐free solid state emissive room temperature phosphorescence (RTP) from carbon dots (CDs). In the present work, limited rotation of the two naphthol rings in (R)‐1,1‐Bi‐2‐naphthol (R‐Binol) has been used to synthesize CDs aimed to obtain emission in the aggregated and RTP states. The R‐Binol‐derived CDs were prepared using an easy one‐pot solvothermal treatment of the precursor. In‐depth structural analysis reveals the presence of twisted naphthalene moiety that resists π−π stacking to make it dual emissive. These CDs are prone to accumulate producing spherical aggregates with 32‐fold enhanced emission in binary THF‐water mixture. Nevertheless, for the first time, we harvested triplet excitons from matrix free CDs generating 23 % PLQY. A phosphor converted light emitting diode (pc‐LED) was also fabricated with the CDs.

Scent marks play a crucial role in both territorial and sexual communication in many species. We investigated how free-ranging dogs respond to scent marks from individuals of different identities in terms of sex and group, across varying strategic locations within their territory. Both male and female dogs showed heightened interest in scent marks compared to control, exhibiting stronger territorial responses, with males being more territorial than females. Overmarking behavior was predominantly observed in males, particularly in response to male scent marks and those from neighboring groups. Behavioral cluster analysis revealed distinct responses to different scent marks, with neighboring group male scents eliciting the most distinct reactions. Our findings highlight the multifaceted role of scent marks in free-ranging dog communication, mediating both territorial defense and intrasexual competition. The differential responses based on the identity and gender of the scent-marker emphasize the complexity of olfactory signaling in this species. This study contributes to understanding the social behavior of dogs in their natural habitat, and opens up possibilities for future explorations in the role of olfactory cues in the social dynamics of the species.

The Warburg effect, which generates increased demand of glucose in cancer cells is a relatively underexplored phenomenon in existing commercial drugs to enhance uptake in cancer cells. Here, we present a chemotherapeutic strategy employing a Ru(II)‐bis‐bipyridyl‐morphocumin complex (2) encapsulated in a self‐assembling glucose‐functionalized copolymer P(G‐EMA‐co‐MMA) (where G=glucose; MMA=methyl methacrylate; EMA=ethyl methacrylate), designed to exploit this effect for enhanced selectivity in cancer treatment. The P(G‐EMA‐co‐MMA) polymer, synthesized via reversible‐addition fragmentation chain transfer (RAFT) polymerization, has a number average molecular weight (Mn,NMR) of 8000 g/mol. Complex 2, stable in aqueous media, selectively releases a cytotoxic, lysosome‐targeting compound, morphocumin, in the presence of excess hydrogen peroxide (H₂O₂), a reactive oxygen species (ROS) prevalent in tumor microenvironments. Additionally, complex 2 promotes ROS accumulation, which may further enhance morphocumin release through a synergistic domino effect. Comparative studies reveal that 2 outperforms its curcumin Ru(II) complex (1) analog in solution stability, organelle specificity, and cellular mechanisms. Both 1 and 2 exhibit phototherapeutic effects under low‐intensity visible light, but their chemotoxicity significantly increases with incubation time in the dark, highlighting the superior chemotherapeutic efficacy of the O,O‐coordinating Ru(II) ternary polypyridyl complexes. Complex 2 induces apoptosis via the intrinsic pathway and shows a 9‐fold increase in selectivity for pancreatic cancer cells (MIA PaCa‐2) over non‐cancerous HEK293 cells when encapsulated in the glucose‐conjugated polymer (DP@2). Glucose deprivation in the culture medium further enhances drug efficacy by an additional 5‐fold. This work underscores the potential of glucose‐functionalized polymers and ROS‐responsive Ru(II) complexes in targeted cancer therapy.

Almost a century on from the culmination of the first revolution in quantum physics, we are poised for another. Even as we engage in the creation of impactful quantum technologies, it is imperative for us to face the challenges in understanding the phenomenology of various emergent forms of quantum matter. This will involve building on decades of progress in quantum condensed matter physics, and going beyond the well-established Ginzburg–Landau–Wilson paradigm for quantum matter. We outline and discuss several outstanding challenges, including the need to explore and identify the organisational principles that can guide the development of theories, key experimental phenomenologies that continue to confound, and the formulation of methods that enable progress. These efforts will enable the prediction of new quantum materials whose properties facilitate the creation of next generation technologies.

An established concept to create radical intermediates is photoexcitation of a catalyst to a higher energy intermediate, subsequently leading to a photoinduced electron transfer (PET) with a reaction partner. The known concept of consecutive photoinduced electron transfer (con‐PET) leads to catalytically active species even higher in energy by the uptake of two photons. Generally speaking, increased photon uptake leads to a more potent reductant. Here, we report the concept of multi‐photoinduced electron transfer catalysis (>2 photons), termed multi‐PET, which is enabled by photoinduced one‐electron reductions of an organic dye. Further irradiation of the doubly reduced species leads to a photoexcited dianionic super‐reductant, which is more potent than Li metal – one of the strongest chemical reductants known. This multi‐photon process which is enabled by 390 nm LEDs allows the cleavage of strong carbon‐fluorine bonds and reduction of other halides even in very electron‐rich substrates. The resulting radicals are quenched by hydrogen atoms or engaged in carbon‐carbon and carbon‐phosphorus bond formations, highlighting the utility of multi‐PET for organic chemistry. In addition, multi‐PET enabled Birch‐type reductions. Spectroscopic, chemical and computational investigations are presented to gain mechanistic insights.

Azotobacter sp. strain CWF10, an aerobic gram negative, oval shaped and motile bacterium, was isolated from a lateritic agricultural soil of Madhya Pradesh, India. The draft genome of the isolate is 5.7 Mb in size, consisting of 14 contigs with 65.09 % G+C content. Average nucleotide identity (94.66%) and digital DNA-DNA hybridization (62%) calculation with closest reference strains underpin the bacterium as a potential novel species. The bacterium has a plethora of plant growth promoting genes that point towards potential ability for enhancement of available nitrogen, biosynthesis of folic acid, among others. Siderophores such as vibrioferrin and crochelin A are also present in the genome which are known to regulate iron uptake. Overall, mining of the genome of Azotobacter sp. strain CWF10 has revealed the potential of this strain for application in regenerative agriculture and sustaining soil health.

Water-soluble nickel(II)-guanidine-based complexes successfully catalyzed the C-H chlorination of a series of hydrocarbons in the presence of NaOCl and acetic acid in water-chloroform (7 : 3, biphasic condition) at room temperature. Majorly chlorinated products (TON ∼680 for cyclohexane) were obtained. Furthermore, C-H bond bromination of cyclohexane, n-hexane, and toluene was also carried out using in situ generation of NaOBr. These putative formations of Ni(III) species were characterized by electron paramagnetic resonance (EPR) spectroscopy, and the plausible mechanism for chlorination was confirmed by DFT calculations.

Rationale Early mortality in intracerebral haemorrhage (ICH) is due to haematoma volume (HV) expansion and there are no effective treatments available other than reduction in blood pressure. Tranexamic acid (TXA) a hemostatic drug which is widely available and safe can be a cost-effective treatment for ICH, if proven efficacious. Hypothesis Administration of TXA in ICH patients when given within 4.5 hours of symptom onset will reduce early mortality at 30 days. Design Indian Trial of Tranexamic acid in Spontaneous Intracerebral Haemorrhage (INTRINSIC Trial) is a multicenter, randomized, open-label, trial enrolling patients aged more than 18 years presenting with non-traumatic ICH within 4.5 hours of symptom onset or when last seen well. Study participants receive 2 grams of TXA administered within 45 minutes while control group receives standard of care. Intensive blood pressure reduction as per INTERACT 2 protocol is followed in done in both groups. Study plans to recruit 3400 patients. Primary outcome is mortality at day 30. Secondary outcomes are radiological reduction of HV at 24 hours from baseline, neurological impairment at day 7 or earlier (if discharged), and assessments of dependency and quality of life at day 90. Summary If proven to be beneficial, TXA will have a major impact on medical management of ICH. Trial registration Clinical Trial Registry India (CTRI/2023/03/050224) and Clinical Trials.gov (NCT05836831)

In response to the growing concerns about the unauthorized use of advanced secondary explosives such as TKX‐50 against non‐combatant targets, there is an urgent need for effective detection methods or techniques to ensure efficient security screening, homeland security, and public safety. Herein, a new polymeric receptor (IV) derived from functionalized tetraphenylethylene moiety (TPE) and 1,3,5‐tris(4‐aminophenyl)benzene (TAPB) moieties for the efficient detection of TKX‐50 through a ‘switch ON’ luminescence response upon specific binding to the explosive, is reported. The observed ‘luminescence ON’ response is rationalized based on a charge transfer complex formation between TKX‐50 and the polymeric receptor IV (Ka = 1.7 × 10⁴ m⁻¹). This is validated by the steady and excited‐state luminescence studies, along with detailed computational studies. The authors’ presumptions are further validated with adequate control studies using an appropriate monomeric derivative (III) of TPE. Moreover, this ‘luminescence ON’ response can be integrated into a smart and user‐friendly Internet of Things (IoT)‐based prototype device. This device can effectively convert optical responses into digital output to develop an optical device for real‐time detection of TKX‐50 in solution. This lightweight, portable device is ideally suited for remote surveillance and monitoring of TKX‐50; such examples are rare in contemporary literature.

Azomethine ylides are typically transient synthons, heavily used in constructing N-heterocycles by dipolar cycloaddition reactions. We report here a pyridyl-tethered isolable azomethine ylide (AY) that unprecedentedly acts as a Frustrated Lewis Pair (FLP) in activating a series of H-E bonds (E = B, Si, Al, O). The reactions are thoroughly probed mechanistically by the aid of DFT calculations and each case appears to be distinct from the rest. While the HBpin activation follows a stepwise mechanism, the same of PhSiH3 has a concerted route. The AlH3 activation is also stepwise but takes place across the 1,5-(C+/N-) dipole involving the pyridyl-N. The H2O activation is better fitted with a ‘relay’ mechanism with two H2O molecules rather than one to interact with AY. The B-B bond of B2pin2 is also cleaved but in an intriguingly different way, by an oxidative addition at a carbene center formed in situ through a 1,3-(C+ to C-) H+ shift. Though the imperative H2 activation fails, a transfer hydrogenation by NH3•BH3 is achieved readily and mechanistically elucidated as a stepwise process. The AY also undergoes FLP-like cycloadditions with various dipolarophiles, among which the addition of CS2 but not of CO2 is alluring and counter-intuitive. DFT analysis again justifies this dichotomy by showing the addition of CS2 as thermodynamically favored but of CO2 as disfavored, mostly due to the larger ring strain in the cycloaddition product in the CO2 case.

Chemistry of functional organic materials is interesting in terms of design and applications. Halogen functionalization of organic molecules is intriguing as besides affecting the intramolecular electronic properties, their presence triggers intermolecular halogen bonds, affecting both packing and bulk properties. We report the rationally substituted halogenated anils of sulfanilamide 1–3 to understand the influence of halogens on molecular packing and bulk properties. The products 1 and 2 exhibit thermal stability beyond 300 ⁰C, whereas 3 undergoes early weight loss, indicating the presence of lattice solvent. The phase purity of the products has been confirmed with powder X‐ray analyses. Products have been further characterized through single‐crystal diffraction studies to understand crystal packing with further support from Hirshfeld studies. X⋯O interactions are predominant interactions and significant interhalogen X⋯X interactions are observed only in 2. The products are feebly emissive in solid‐state. Interestingly, 2 and 3 in thin film forms undergo emission quenching, whereas 1 exhibits augmented emission. AIE active anil 1 has been used for the sensing of explosive aromatic compound like picric acid.

Azotobacter sp. strain CWF10, an aerobic gram negative, oval shaped and motile bacterium, was isolated from a lateritic agricultural soil of Madhya Pradesh, India. The draft genome of the isolate is 5.7 Mb in size, consisting of 14 contigs with 65.09 % G+C content. Average nucleotide identity (94.66%) and digital DNA-DNA hybridization (62%) calculation with closest reference strains underpin the bacterium as a potential novel species. The bacterium has a plethora of plant growth promoting genes that point towards potential ability for enhancement of nitrogen, biosynthesis of folic acid, among others. Siderophores such as vibrioferrin and crochelin A are also present in the genome which are known to regulate iron uptake.

Molecular clouds are the prime locations of star formation. These clouds contain filamentary structures and cores which are crucial in the formation of young stars. In this work, we aim to quantify the physical properties of structural characteristics within the molecular cloud L1251 to better understand the initial conditions for star formation. We applied the getsf algorithm to identify cores and filaments within the molecular cloud L1251 using the Herschel multi-band dust continuum image, enabling us to measure their respective physical properties. Additionally, we utilized an enhanced differential term algorithm to produce high-resolution temperature maps and column density maps with a resolution of ${13.5}''$. We identified 122 cores in the region. Of those, 23 are protostellar cores, 13 are robust prestellar cores, 32 are candidate prestellar cores (including 13 robust prestellar cores and 19 strictly candidate prestellar cores), and 67 are unbound starless cores. getsf also found 147 filament structures in the region. Statistical analysis of the physical properties (mass (M), temperature (T), size and core brightness (hereafter, we are using the word luminosity (L)) for the core brightness) of obtained cores shows a negative correlation between core mass and temperature and a positive correlation between (M/L) and (M/T). Analysis of the filaments gives a median width of 0.14 pc and no correlation between width and length. Out of those 122 cores, 92 are present in filaments ($\sim$ 75.4%) and the remaining were outside them. Out of the cores present in filaments, 57 ($\sim$ 62%) cores are present in supercritical filaments ($M_\textrm{line}>16 \ M_{\odot }/\textrm{pc}$).

Olivine (M2SiO4; M: Mg, Fe), constituting about 60% (by volume) of the upper mantle of our Earth, contains ~10% Fe (at the M-octahedral site). The Fe2+ ion is known to preferentially occupy one of the two inequivalent M-octahedral sites, namely M1 and M2, in the crystal structure of olivine. The site preference of Fe in olivine as a function of increasing temperature has been a matter of great debate for over three decades. However, later first-principles studies found that Fe preferred the M1 site for all temperatures of interest. A more recent study Mandal et al. (J. Geophys. Res. Solid Earth 117 B12, 2012, https://doi.org/10.1029/2012JB009225) incorporated the effect of pressure in addition to high temperature and found that increased pressure may bring on a cross-over of the site preference of Fe in olivine. This was proposed to be the cause behind the Hales discontinuity, which is observed at a depth of ~100 km deep inside the Earth. In a bid to understand the microscopic origin behind (i) the cross-over (if any) and (ii) the drastic change in elasticity of olivine as Fe migrates from M1 site to the M2 site at high pressure and temperature, we have re-addressed the problem using a combination of ab-initio molecular dynamics simulation (AIMD) and quasi-harmonic approximation (QHA). Our calculations find that, thermodynamically, Fe2+ prefers the M1 site, and that there is no cross-over under high pressure and temperatures that are prevalent in the Earth’s upper mantle. Since the distribution of Fe in the mantle might not be homogeneous, the effect of increased Fe concentration (to capture local effects) has also been investigated. We find that increased Fe concentration does not have any effect on the site preferred by Fe2+ in the olivine lattice. The calculated thermoelastic properties of olivine with Fe at M1 site and M2 site, respectively, indicate that even the hypothetical situation of cross-over of Fe2+ from the M1 to M2 site, cannot account for the Hales discontinuity, as proposed previously (Mandal et al. 2012).

Organic light‐emitting diodes (OLEDs) have revolutionized display and lighting technologies, offering unparalleled design, device flexibility, vibrant colors, and energy efficiency. In this comprehensive review we elucidate the evolution of OLED technology, summarizing its progression from the fundamental principles of fluorescence (1st generation) and phosphorescence (2nd generation) to the emergence of thermally activated delayed fluorescence (TADF) (3rd generation), hyper fluorescence (4th generation), and exceptional future generation OLEDs. This review highlights the development and challenges of early‐generation OLEDs, scrutinizing their mechanisms, emitters, and limitations. As TADF OLEDs mark a significant paradigm shift, we explore their enhanced efficiency and potential for cost‐effective production without the involvement of toxic heavy metals. Building upon this foundation this review explores the burgeoning concepts of hyper‐fluorescence and 5th‐generation OLEDs, poised to push the boundaries of color purity, efficiency, and operational stability. This consolidated comprehensive exploration described herein may provide enormous information for designing future‐generation OLED materials for sustainable development.

Water is indispensable for the survival of all living organisms. Rapid growth in population and other industries have led to over-usage and wastage of this non-renewable resource, which in turn has caused a brisk rise in wastewater and shortage of clean water for many. Hence, the availability of clean water is the need of the hour in today’s world. The wastewater generated is full of contaminants that remain even on filtration, leading to adverse health impacts on people. A plethora of methods have been explored for wastewater treatment but due to various shortcomings, their usage has subdued over the past decade. Thus, the advent of the latest and more feasible methods is being explored in order to curb this issue. Nanotechnology is one such advancement in this field, in which a matter is maneuvered at the molecular level to obtain the required properties for a superior result. Nanomaterials are emerging as a promising technology for wastewater treatment owing to their unique features like high surface-to-area ratio, compact size, high adsorption capacity, high specificity, and better efficiency. In this chapter, the application of nanotechnology for wastewater treatment and its potential role in attaining circular economy has been discussed.

Antimicrobial resistance (AMR) is one of the major global health challenges and influenced by unregulated consumption of antibiotics in food, pharmaceuticals, and application in animal husbandry. The antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) are ubiquitous—in soil, sediment, sludge, ground and wastewater, freshwater, municipal wastes, and even in drinking water. The build-up of environmental antibiotic residues directly influences the spread of antibiotic resistance. The prevalence and effects of antibiotic residues in across environments necessitates mapping risks associated with this silent pandemic. Wastewater treatment plants (WWTPs) are designated to reduce biological communities linked to infection and possibly can have consequences for ARGs and ARBs. Presently, WWTPs are considered to be one of the major reservoirs of animal and human borne pathogens; represent a potent hub for horizontal gene transfer among microbiomes. In this chapter, an effort has been made to summarize the prevalence of antimicrobial resistance in fecal coliforms and other associated microorganisms along with current scenario of the importance of WWTPs in tackling microbial infections linked to ARGs.

Circular atomtronics is known to exhibit a uniform ground state, unlike elliptical atomtronics. In elliptical atomtronics, the matter wave tends to accumulate along the semimajor edges during its time dynamics, which we depict by the survival function. Consequently, the dynamical time scales become coupled to the eccentricity, making the dynamics nontrivial for applications. We report that an appropriate dispersion management can decouple the time scales from the eccentricity. One can choose the suitable dispersion coefficient from the overlap function involving the corresponding ground state. We focus on producing distinct fractional matter waves inside an elliptical waveguide to achieve efficient atom interferometry. The said dispersion engineering can recover fractional revivals in the elliptical waveguide, analogous to the circular case. We demonstrate atom interferometry for the engineered elliptical atomtronics, where matter wave interference is mediated by an external harmonic trap for controlled interference patterns.

The perylene diimide (PDI) is an underexplored synthetic organic dye with significant potential in photoredox catalysis. We have developed a good chemo‐ and regioselective, atom‐economical methodology for synthesizing trifluoroethylated saturated heterocyclic derivatives and trifluoroethyl‐containing cyclobutane derivatives. This process involves the generation of trifluoromethyl radical from the Langlois (CF3SO2Na) reagent under photoredox conditions, which selectively reacts with the electron‐rich terminal double/triple bonds in the diene/enyne framework. The resulting intermediate undergoes a cascade cyclization, yielding the desired compounds in a redox‐neutral manner. Our methodology operates under very mild conditions, eliminating the need for transition metals and external oxidizing agents. It is broadly applicable across various substrates and is supported by comprehensive mechanistic insights from regular photophysical experiments.