meta-Fluorophores: an uncharted ocean of opportunities.

meta-Fluorophores (MFs) are unique ultra-light (in terms of molecular weight (MW)) fluorophores exhibiting luminescence with a wide colour gamut ranging from blue to the NIR. Single benzenic MFs are easy to synthesize, are quite bright (with photoluminescence quantum yield (PLQY) as high as 63%) and exhibit very large Stokes shift (as high as 260 nm (8965 cm-1)), with large solvatochromic shift (as high as 175 nm), and very long excited-state-lifetime (as high as 26 ns) for such ultra-light fluorophores. An emission maximum of ≥600 nm has been achieved with an MF in a polar medium having a MW of only 177 g mol-1 and in a nonpolar medium having MW of only 255 g mol-1; therefore, a large-sized π-conjugated para-fluorophore is no longer a prerequisite for red/NIR emission. Structurally varied MFs pave the way for creating an ocean of opportunities and are thus promising for replacing para-fluorophores for different applications, ranging from bioimaging to LEDs.

Generation of higher-order topological insulators using periodic driving.

Topological insulators (TIs) are a new class of materials that resemble ordinary band insulators in terms of a bulk band gap but exhibit protected metallic states on their boundaries. In this modern direction, higher-order TIs (HOTIs) are a new class of TIs in dimensionsd > 1. These HOTIs possess(d-1)-dimensional boundaries that, unlike those of conventional TIs, do not conduct via gapless states but are themselves TIs. Precisely, annth orderd-dimensional higher-order TI is characterized by the presence of boundary modes that reside on itsdc=(d-n)-dimensional boundary. For instance, a three-dimensional second (third) order TI hosts gapless (localized) modes on the hinges (corners), characterized bydc=1(0). Similarly, a second-order TI (SOTI) in two dimensions only has localized corner states (dc=0). These higher-order phases are protected by various crystalline as well as discrete symmetries. The non-equilibrium tunability of the topological phase has been a major academic challenge where periodic Floquet drive provides us golden opportunity to overcome that barrier. Here, we discuss different periodic driving protocols to generate Floquet HOTIs while starting from a non-topological or first-order topological phase. Furthermore, we emphasize that one can generate the dynamical anomalousπ-modes along with the concomitant 0-modes. The former can be realized only in a dynamical setup. We exemplify the Floquet higher-order topological modes in two and three dimensions in a systematic way. Especially, in two dimensions, we demonstrate a Floquet SOTI (FSOTI) hosting 0- andπcorner modes. Whereas a three-dimensional FSOTI and Floquet third-order TI manifest one- and zero-dimensional hinge and corner modes, respectively.

A Three-Component Arene Difunctionalization: Merger of C(sp3 )/(sp2 )-H Bond Addition.

A tandem three-component C-H bond addition involving the activation of an inert C(sp3 )-H bond is reported. The process enables the direct regioselective synthesis of 1,2-difunctionalized arenes with the formation of C(sp3 )- and C(sp2 )-C(arene) bonds. 2-Iodobenzoic acid derivatives behave as masked bifunctional reagent (BFR) and react with 2-pyridyl-methyl sulfoximine (MPyS) protected aliphatic acids bearing α,α-disubstituted groups, and alkenes to produce ß-aryl-δ-alkenyl amide derivatives in a single operation. The transformation involves Pd(II)/Pd(IV) and Pd(II)/Pd(0) catalytic systems. Detailed mechanistic studies, including density functional theory (DFT) calculations, reveal the formation of large T-shaped palladacycles and the onset of a 1,2-palladium migration via decarboxylation.

Non-stoichiometric carbamazepine cocrystal hydrates of 3,4-/3,5-dihydroxybenzoic acids: coformer-water exchange.

The cocrystallisation of carbamazepine (CBZ) with 3,4-/3,5-dihydroxybenzoic acids (34/35DHBA) with different stoichiometries formed molecular alloys, exchanging a water molecule, in their isostructural CBZ dihydrate form. Furthermore, we show a correlation between the mechanical properties of the CBZ-DHBA cocrystals with the amount of coformer present.

Beneficial Intrinsic Hole Trapping and Its Amplitude Variation in a Highly Photoluminescent Toxic-Metal-Free Quantum Dot.

Intrinsic hole trapping as well as hole detrapping have not been observed for any quantum dot (QD) or perovskite nanocrystal (PNC) system. Moreover, amplitude variation of intrinsic hole trapping (or detrapping) has not been reported at all for any QD or PNC system. However, for a CuInS2-based core/alloy-shell (CAS) QD system, (a) both intrinsic hole trapping and detrapping have been observed and (b) very significant amplitude variations of hole trapping (∼16 to ∼42%) and hole detrapping (∼44 to 23%) have been observed. Unlike detrimental electron trapping, hole trapping has been shown to be beneficial, having a direct correlation toward increasing PLQY to 96%. Simultaneous electron and hole trapping has been shown to be quite beneficial for the CuInS2-based CAS QD system leading to the longest ON time (∼130 s) for which a nontoxic metal-based QD remains only in the ON-state without blinking.

Efficient Storage and Encryption of 32-Slice CT Scan Images Using Phase Grating.

Medical images are treated as sensitive as it carries patients' confidential information and hence must be protected from unauthorized access. So, a strong encryption mechanism is a primary criterion to transmit these images over the internet to protect them from intruders. In many existing algorithms, noise affection in the extracted images is high, hence not suitable for medical data encryption. Here, we present a new method using phase grating to multiplex as well as encrypting 32 cross-sectional CT scan images (slices) in a single canvas for optimization of storage space and improvement of security. The entire process is divided into a few steps. Before transmission, the main canvas is encrypted with the help of a random phase matrix. The main canvas is further encrypted by the transposition method to enhance security. After decryption, inverse Fourier transform is applied at the proper location of the decrypted canvas to extract the images from the spectra. Quality is measured with peak-signal-to-noise ratio and correlation coefficient methods. Here, it is greater than 38 and the correlation coefficient is close to 1 for all images, thereby indicating of good quality of extracted images. The effect of three common cyber-attacks (viz. known-plaintext attack, chosen-plaintext attack, and chosen-ciphertext attack) is also presented here. The correlation coefficient during cyber-attacks is found to be close to zero, which implies the robustness of the algorithm against cyber-attacks. Finally, a comparison with existing techniques shows the effectiveness of the proposed method.

Interim Analysis of Impact of Adding Low Dose Pulmonary Radiotherapy to Moderate COVID-19 Pneumonia Patients: IMpaCt-RT Study.

Background: Treatment for coronavirus disease 2019 (COVID-19) pneumonia remains largely supportive till date and multiple clinical trials took place within the short span of time to evaluate the role of investigational therapies. The anti-inflammatory effect of low dose whole lung radiation in treating pneumonia has been documented earlier. This clinical trial analyzed the effect of low dose radiation therapy (LDRT) in a moderately affected COVID-19 pneumonia patient cohort and has evaluated its effect in stopping the conversion of moderate disease into severe disease. Methods: Patients with moderate COVID-19 pneumonia as characterized by the Ministry of Health and Family Welfare (MOHFW), Government of India, were randomized (1:1) to low dose whole lung radiation versus no radiation. All treatment of patients was concurrently being given as per institutional protocol. Patients were followed up with clinical and laboratory parameters monitored on Days 1, 3, 7, and 14. Computed tomography scan (CT scan) of thorax was performed on Days 1 and 7. Patients were evaluated for conversion of moderate into severe disease as per National Early Warning Score-2 (NEWS-2 score) as the primary end point. The secondary endpoints included changes in ratio between peripheral capillary oxygen saturation and fraction of inspired oxygen (SpO2/FiO2), biochemical markers, 25-point CT severity score, and radiation induced acute pulmonary toxicities. Findings: At the interim analysis, there were seven patients in the radiation arm and six in the control. A whole lung LDRT improved the outcome of SpO2/FiO2 at Day 3; however it did not convert into a statistically significant improvement for the NEWS-2 score. The serum levels of LDH, CRP, Ferritin and D-dimer were significantly reduced on 14 days in the LDRT arm in comparison to the baseline value but were not significant between the two groups. Interpretation: LDRT seems to have the potential to prevent moderate COVID-19 pneumonia from a deteriorating to severe category. However, further randomized clinical trial with an adequate number of such patients is warranted to establish the definitive role of LDRT in the management of COVID-19 pneumonia. Funding: An intramural research project bearing code: I-27/621, was sanctioned from the All India Institute of Medical Sciences, Patna, India. Clinical Trial Registration: Clinical Trials Registry-India (CTRI/2021/06/033912, 25th May 2021) ctri.nic.in/Clinicaltrials/login.php.

Multiple annulations of inert C(sp2)-H bonds with alkynes.

Transition-metal catalyzed directing group (DG) assisted annulation of inert C-H bonds leads to the formation of complex molecular frameworks from readily accessible substrates. Thus, multiple annulation of less functionalized substrates with unsaturated species leads to the construction of structurally diverse fused poly(hetero)cycles. The directed inert C(arene)-H bond activation and the mode of TM-migration in this process could enabled obatining L-type [involves DG heteroatom, o-C(arene)-H bond, and C(arene)-H bond of aryl-motif in alkyne], Y-type [involves two heteroatoms of the DG and o-,o'-C(arene)-H bonds], and B-type [involves o-C(arene)-H bond and m-C(arene)-H bond] π-extended annulation products. The coordination preference of the DG heteroatom makes the transformation chemo- and regio-selective. This article underlines the conceptual development of unsymmetrical multiple annulation of arene C(sp2)-H bonds with alkynes, which is exceedingly appealing and highly important.

CerealESTDb: A Comprehensive Resource for Abiotic Stress-Responsive Annotated ESTs With Predicted Genes, Gene Ontology, and Metabolic Pathways in Major Cereal Crops.

Cereals are the most important food crops and are considered key contributors to global food security. Loss due to abiotic stresses in cereal crops is limiting potential productivity in a significant manner. The primary reasons for abiotic stresses are abrupt temperature, variable rainfall, and declining nutrient status of the soil. Varietal development is the key to sustaining productivity under influence of multiple abiotic stresses and must be studied in context with genomics and molecular breeding. Recently, advances in a plethora of Next Generation Sequencing (NGS) based methods have accelerated the enormous genomic data generation associated with stress-induced transcripts such as microarray, RNAseq, Expressed Sequenced Tag (ESTs), etc. Many databases related to microarray and RNA-seq based transcripts have been developed and profusely utilized. However, an abundant amount of transcripts related to abiotic stresses in various cereal crops arising from EST technology are available but still remain underutilized in absence of a consolidated database. In this study, an attempt has been made with a primary goal to integrate, analyse, and characterise the available resources of ESTs responsive to abiotic stresses in major cereals. The developed CerealESTdb presents a customisable search in two different ways in the form of searchable content for easy access and potential use. This database comprises ESTs from four major cereal crops, namely rice (Oryza sativa L.), wheat (Triticum aestivum L.), sorghum (Sorghum bicolour L.), and maize (Zea mays L.), under a set of abiotic stresses. The current statistics of this cohesive database consists of 55,826 assembled EST sequences, 51,791 predicted genes models, and their 254,609 gene ontology terms including extensive information on 1,746 associated metabolic pathways. We anticipate that developed CerealESTdb will be helpful in deciphering the knowledge of complex biological phenomena under abiotic stresses to accelerate the molecular breeding programs towards the development of crop cultivars resilient to abiotic stresses. The CerealESTdb is publically available with the URL http://cabgrid.res.in/CerealESTDb.

Sulfur and Nitrogen Modulated One-Pot Double Annulation of Arenes.

The sulfur and nitrogen moieties of methylphenyl sulfoximine (MPS)-enabled aryl thioamides are independently involved in annulation with unactivated alkynes to construct the unusual 6,6-fused thiopyranoisoquinoline skeletons. The MPS directing group plays a vital role in making this unprecedented Ru-catalyzed one-pot double annulation of aryl thioamides with alkynes chemo- and regioselective. Both the o,o'-C-H bonds of the aryl motif are sequentially functionalized to form four bonds [C-C, C-S and C-C, C-N] in a single operation by overcoming the undisputed challenges, viz. the "S" poisoning effect on the transition-metal catalyst and the susceptibility of S to oxidation. The novel isothiochromene-1-one skeletons are successfully constructed, as the annulation is initiated with S in preference over the N motif of thioamides with alkynes. The preliminary photophysical properties of the thiopyrano-isoquinoline derivatives are also discussed.

The Effects of Electronegativity of X and Hybridization of C on the X-C⋠⋠⋠O Interactions: A Statistical Analysis on Tetrel Bonding.

Cone and distance-cone corrected statistical analyses have been performed on X-C⋅⋅⋅O (X=H, B, C, N, O and F; the C atom is sp2 and sp3 hybridized) tetrel bonds. The sp3 -C and sp2 -C prefer to form the interactions through σ-hole (∠XCO≈180°) and π-hole (∠XCO≈90°), respectively. With the increase in electronegativity of X, the preference for the particular angles of the respective geometries increases and the C⋅⋅⋅O distance becomes shorter. The angular preference is found to be more prominent in the cases of π-hole interactions than that in the σ-hole interactions. A similar distance-cone corrected statistical analysis on O=C⋅⋅⋅O interaction also suggests that the preferred ∠OCO angle is ∼90° and the preferred C⋅⋅⋅O distance is around the sum of van der Waals radii (3.22 Å) of the C and O atoms. However, a cone-corrected statistical analysis on X-Si⋅⋅⋅O interactions suggests that the preference for linearity in this case is much higher than that for the X-C⋅⋅⋅O σ-hole interactions.

Harnessing sulfur and nitrogen in the cobalt(iii)-catalyzed unsymmetrical double annulation of thioamides: probing the origin of chemo- and regio-selectivity.

An unconventional cobalt(iii)-catalyzed one-pot domino double annulation of aryl thioamides with unactivated alkynes is presented. Sulfur (S), nitrogen (N), and o,o'-C-H bonds of aryl thioamides are involved in this reaction, enabling access to rare 6,6-fused thiopyrano-isoquinoline derivatives. A reverse 'S' coordination over a more conventional 'N' coordination of thioamides to the Co-catalyst specifically regulates the formation of four [C-C and C-S at first and then C-N and C-C] bonds in a single operation, a concept which is uncovered for the first time. The power of the N-masked methyl phenyl sulfoximine (MPS) directing group in this annulation sequence is established. The transformation is successfully developed, building a novel chemical space of structural diversity (56 examples). In addition, the late-stage annulation of biologically relevant motifs and drug candidates is disclosed (17 examples). The preliminary photophysical properties of thiopyrano-isoquinoline derivatives are discussed. Density functional theory (DFT) studies authenticate the participation of a unique 6π-electrocyclization of a 7-membered S-chelated cobaltacycle in the annulation process.

Primary hydatid disease of fallopian tubes: the risk of infertility looms large.

A 45-year-old postmenopausal woman from a rural area presented with a painless lower abdominal lump. Contrast-enhanced computed tomogram of abdomen revealed a well defined hypodense pelvic cystic lesion with multiple daughter cysts suggestive of hydatid disease. The liver was free of cysts on imaging. On laparotomy, the cyst cavity was found to be communicating with the fimbriated ends of both the fallopian tubes. Cyst excision along with hysterectomy and bilateral salpingo-oophorectomy was performed. Histopathology confirmed presence of hydatid disease by demonstrating daughter cysts and laminated membrane completely filling up the tube lumens. The uterus and ovary were uninvolved. While the management is straightforward in postmenopausal women, the risk of infertility looms large in young patients with bilateral fallopian tube hydatid disease. Proper preoperative counseling is thus essential in the patients with pelvic hydatid disease to safeguard against future litigations.

Acid-Functionalised Magnetic Ionic Liquid [AcMIm]FeCl4 as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and Regioselective Friedel-Crafts Acylation.

An acid-functionalised, magnetic, room-temperature ionic liquid, 1-acyl-3-methylimidazolium tetrachloroferrate ([AcMIm]FeCl4 ), was synthesised and its optical, magnetic, and thermal properties were investigated. The magnetic moment (0.05402 emu in 2 T magnetic fields) showed strong paramagnetic behaviour, and thermogravimetric analysis indicated very good thermal stability with a decomposition temperature higher than 230 °C. Additionally, [AcMIm]FeCl4 efficiently catalysed the oxidative ipso-hydroxylation of arylboronic acids and regioselective Friedel-Crafts acylation without external organic solvent or additives, such as acids, base, and ligands. This functionalised ionic liquid, [AcMIm]FeCl4 , was recycled and reused at least six times without significant loss of its catalytic properties and stability.

Transport and noise properties of a normal metal-superconductor-normal metal junction with mixed singlet and chiral triplet pairings.

We study transport and zero frequency shot noise properties of a normal metal-superconductor-normal metal (NSN) junction, with the superconductor having mixed singlet and chiral triplet pairings. We show that in the subgapped regime when the chiral triplet pairing amplitude dominates over that of the singlet, a resonance phenomena emerges out at zero energy where all the quantum mechanical scattering probabilities acquire a value of 0.25. At the resonance, crossed Andreev reflection mediating through such junction, acquires a zero energy peak. This reflects as a zero energy peak in the conductance as well depending on the doping concentration. We also investigate shot noise for this system and show that shot noise cross-correlation is negative in the subgapped regime when the triplet pairing dominates over the singlet one. The latter is in sharp contrast to the positive shot noise obtained when the singlet pairing is the dominating one.

Geometric quantum noise of spin.

The presence of geometric phases is known to affect the dynamics of the systems involved. Here, we consider a quantum degree of freedom, moving in a dissipative environment, whose dynamics is described by a Langevin equation with quantum noise. We show that geometric phases enter the stochastic noise terms. Specifically, we consider small ferromagnetic particles (nanomagnets) or quantum dots close to Stoner instability, and investigate the dynamics of the total magnetization in the presence of tunneling coupling to the metallic leads. We generalize the Ambegaokar-Eckern-Schön effective action and the corresponding semiclassical equations of motion from the U(1) case of the charge degree of freedom to the SU(2) case of the magnetization. The Langevin forces (torques) in these equations are strongly influenced by the geometric phase. As a first but nontrivial application, we predict low temperature quantum diffusion of the magnetization on the Bloch sphere, which is governed by the geometric phase. We propose a protocol for experimental observation of this phenomenon.

Synergistic regulatory networks mediated by microRNAs and transcription factors under drought, heat and salt stresses in Oryza Sativa spp.

BACKGROUND: Transcription factors (TFs) and microRNAs (miRNAs) are primary gene regulators within the cell. Regulatory mechanisms of these two main regulators are of great interest to biologists and may provide insights into the abiotic and biotic stresses. However, the interaction between miRNAs and TFs in a gene regulatory network (GRN) still remains uncovered. Previous research has been mostly directed at inferring either miRNA or TF regulatory networks from data. However, networks involving a single type of regulator may not fully reveal the complex gene regulatory mechanisms, therefore study of interplay among these two regulators in gene regulation is important towards explaining the mechanism of different abiotic stresses. RESULT: Oligonucleotide microarrays containing 51,279 transcripts were used to identify total 133 salt responsive target genes regulated by 11 TFs that are also differentially regulated by miRNA under salinity, heat and drought stresses in Oryza sativa. TF's-target interactions which are most enriched in their downstream regulation were also identified. Many genes whose encoded proteins are implicated in response to light and radiation stimulus, hormone stimuli, oxidative stress, copper ion binding and electron transport were found to be enriched. However the majority were novel for the combined abiotic stress, which indicates that there are a great number of genes induced after the exposure these abiotic stresses and regulated by miRNA. CONCLUSION: Analysis of the expression profile data of Oryza provides clues regarding some putative cellular and molecular processes that are undertaken in response to these stresses. The study also identified a large number of candidate functional genes that appear to be constitutively involved in salt, drought and heat stresses tolerance. Further examination of these genes may enable the molecular basis of abiotic stress tolerance in Oryza, to be elucidated.

Transport signatures of fractional fermions in Rashba nanowires.

We theoretically study transport through a semiconducting Rashba nanowire (NW) in the presence of uniform and spatially modulated magnetic fields. The system is fully gapped, and the interplay between the spin orbit interaction and the magnetic fields leads to fractionally charged fermion (FF) bound states of the Jackiw-Rebbi type at each end of the nanowire. We investigate the transport and noise behavior of a N/NW/N system, where the wire is contacted by two normal leads (N), and we look for possible signatures that could help in the experimental detection of such states. We find that the differential conductance and the shot noise exhibit a subgap structure which fully reveals the presence of the FF state. Alternatively, another confirmation of the presence of the FFs is provided by a conductance measurement in an Aharonov-Bohm setup, where the FFs are responsible for oscillations with double period. Our predictions can be tested in InSb/InAs nanowires and are within reach of the present technology.

Compensation of rotation effect in a combination of retarders.

In a cascaded system comprising a combination of oblique retarders, the effect of optical rotation is observed in addition to the overall retardation. This shows that the combined system does not behave as a pure oblique retarder. Analyzing such a general system using Pauli Spin matrices, it is shown that the effect of optical rotation may be completely annulled through the use of a suitably oriented retarder at the output of the cascaded system. The analysis assumes monochromaticity of the illuminating light beam.

Achromatic quarter-wave plate using crystalline quartz.

Achromatic wave plates are ideal components for use with tunable and multiline laser systems, broadband sources, and in astronomical instrumentation. The present study deals with the design and characteristics of two different quarter-wave achromatic retarders in the 500-700 nm range, using a cascaded system of two birefringent plates. The first of these shows a variation of less than ±0.5°, whereas the second system shows a variation of ±4° where the azimuth remains constant. Finally, a comparison between the two systems is made. The succinct and simple Jones matrix formalism has been used to derive the general expression for the equivalent retardation and azimuth of the combinations. It appears that the proposed arrangement has the promise of producing good achromatic combinations.