Magnetic phases of XY model with three-spin terms: interplay of topology and entanglement.

Magnetic and topological properties along with quantum correlations in terms of several entanglement measures have been investigated for an antiferromagnetic spin-1/2 XY model in the presence of transverse magnetic field and XZX-YZY type of three-spin interactions. Symmetries of the spin Hamiltonian have been identified. Under the Jordan-Wigner transformation, the spin Hamiltonian converted into spinless superconducting model with nearest neighbor hopping and Cooper pairing terms in addition to next nearest neighbor Cooper pairing potential. Long range antiferromagnetic order has been studied in terms of staggered spin-spin correlation functions, while the topological orders have been characterized by winding numbers. Magnetic and topological phase diagrams have been prepared. Faithful coexistence of magnetic and topological superconducting phases is found in the entire parameter regime. Boundaries of various quantum phases have been marked and positions of bicritical points have been identified. .

Comparative study of the outcomes of newly developed polypropylene-based modified trabeculectomy and glaucoma shunt surgery in neovascular glaucoma.

BACKGROUND: Neovascular glaucoma (NVG) is a secondary glaucoma with a poor visual prognosis. Trabeculectomy with antifibrotic agents, glaucoma drainage devices (GDDs), and cyclo-destructive procedures are recommended in patients who are refractory to medical management. However, due to the poor success rate of conventional trabeculectomy and the higher cost of GDDs, alternative procedures need to be looked at. PURPOSE: To compare the surgical outcomes and economic aspects of a newly developed polypropylene suture bed-based modified trabeculectomy to Ahmed glaucoma valve (AGV) implantation for NVG. METHODS: It was a prospective interventional study conducted at a tertiary care center between 2018 and 2020. Consecutive patients with NVG with a minimum follow-up of 18 months were included. Surgical outcomes are mainly based on intraocular pressure (IOP) control and the cost of surgery. RESULTS: Sixty eyes were included out of which 40 (60.6%) underwent modified trabeculectomy and 20 (33.7%) underwent AGV. At the final follow-up, no significant difference (P < 0.05) was found between the surgical outcomes of both groups. The complete success rate (IOP < 21 mm Hg without antiglaucoma medications) was 60 and 65% while the qualified success rate (IOP < 21 mm Hg with antiglaucoma medications) was 30 and 25% in modified trabeculectomy and AGV groups, respectively, at final follow-up. The cost of surgery was significantly higher in the AGV group (P < 0.0001). CONCLUSION: Modified trabeculectomy as described might be a better alternative for NVG eyes.

Topological phases of monolayer and bilayer depleted Lieb lattices.

Existence of nontrivial topological phases in a tight binding Haldane-like model on the depleted Lieb lattice is reported. This two-band model is formulated by considering the nearest-neighbor (NN), next-NN (NNN) and next-NNN hopping terms along with complex phase which breaks the time reversal symmetry of this semi-metallic system. Topological feature of this model is studied along with the presence of sublattice symmetry breaking staggered onsite energy. Combined effect of these two broken symmetries is found crucial for an additional transition between nontrivial and trivial phases. System exhibits two types of phase transitions, say, between two nontrivial phases and nontrivial to trivial phases. Nonzero Chern numbers, existence of Hall plateau and symmetry protected edge states confirm the presence of the nontrivial phases. This two-band system hosts four different types of phases where two are topological. Additionally topological properties of stacked bilayer of the depleted Lieb lattices is also studied with similar Haldane-like Hamiltonian. This four-band system is found to host Chern insulating phases, with higher values of Chern numbers supported by in-gap edge states.

Central Retinal Artery Occlusion in COVID-Associated Mucormycosis.

Introduction: Significant surge of mucormycosis was reported in the Indian Subcontinent during the second wave of the COVID-19 pandemic. COVID-associated mucormycosis (CAM) was defined as the development of features of mucormycosis with prior or current history of COVID-19 infection. Rapid angioinvasion is an important characteristic of mucormycosis. Authors intended to find out the prevalence of retinal arterial occlusion and its association with vascular embolic occlusion elsewhere in the body among CAM patients in this study. Methods: This was an observational study. All consecutive-confirmed cases of mucormycosis (n = 89) and age-/gender-/risk factor-matched controls (n = 324) admitted in the designated COVID center were included in the study. All cases and controls underwent comprehensive ophthalmological, otorhinological, and neurological examinations. All necessary investigations to support the clinical diagnosis were done. Qualitative data were analyzed using the Chi-square test. Quantitative data for comparison of means between the cases and controls were done using unpaired t-test. Results: Twenty-one (23.59%) patients manifested the defined outcome of central retinal artery occlusion (CRAO). Among age-matched control, with similar diabetic status, none had developed the final outcome as defined (P < 0.05). About 90.47% of subjects with CRAO presented with no perception of light vision. Thirteen subjects (61.9%) with the final outcome developed clinical manifestations of stroke during the course of their illness with radiological evidence of watershed infarction (P = 0.001). Orbital debridement was performed in 9 (42.85%) subjects while orbital exenteration was done in 8 (38.09%) subjects. Conclusions: CRAO in CAM patients was found to have aggressive nature turning the eye blind in a very short period of time. CRAO can serve as a harbinger for subsequent development of more debilitating and life-threatening conditions such as stroke among CAM patients.

Engineering topological phases of any winding and Chern numbers in extended Su-Schrieffer-Heeger models.

Simple route of engineering topological phases for any desired value of winding and Chern numbers is found in the Su-Schrieffer-Heeger (SSH) model by adding a further neighbor hopping term of varying distances. It is known that the standard SSH model yields a single topological phase with winding number,ν = 1. In this study it is shown that how one can generate topological phases with any values of winding numbers, for examples,ν=±1,±2,±3,…,in the presence of a single further neighbor term which preserves inversion, particle-hole and chiral symmetries. Quench dynamics of the topological and trivial phases are studied in the presence of a specific nonlinear term. Another version of SSH model with additional modulating nearest neighbor and next-nearest-neighbor hopping parameters was introduced before which exhibit a single topological phase characterized by Chern number,C=±1. Standard form of inversion, particle-hole and chiral symmetries are broken in this model. Here this model has been studied in the presence of several types of parametrization among which, for a special case the system is found to yield a series of phases with Chern numbers,C=±1,±2,±3,….In another parametrization, multiple crossings within the edge states energy lines are found in both trivial and topological phases. Topological phase diagrams are drawn for every case. Emergence of spurious topological phases is also reported.

A Prospective Observational Study on Changes in Intraocular Pressure and Iridocorneal Angle Following the Use of Escitalopram and Amitriptyline.

Background: Depression has emerged as one of the prime morbidities affecting professional and personal lives worldwide. Antidepressants are one of the mainstays of management of depressive episodes. Although antidepressants are considered a safe class of drugs, the studies examining the effects of antidepressant prescription on intraocular pressure (IOP) have shown a propensity to increase IOP, but not consistently. This study aimed to compare the changes in IOP and iridocorneal angle in drug-naïve patients with depressive episodes prescribed escitalopram or amitriptyline. Methods: Overall, 109 patients were recruited, of which 53 were prescribed amitriptyline and 56, escitalopram. A comparison of IOP and the iridocorneal angle at weeks 0, 4, and 8 was done using a two-way repeated-measures analysis of variance (two-way RM analysis of variance). Results: Patients initiated on escitalopram tended to show a higher rise in the IOP (left eye-[F = 3.27; P = 0.04]; right eye [F = 2.47; P = 0.08]). No difference was found in the iridocorneal angles in any of the four quadrants across both eyes. Conclusions: Escitalopram use had an association with an increase in IOP. While initiating patients on antidepressants, clinicians should be aware of this possibility, which can lead to ocular emergencies, and obtain a proper history of ocular morbidities.

Prospective evaluation of wipe-out after glaucoma filtration surgery in eyes with split fixation.

Purpose: To assess the incidence and cause of idiopathic, irreversible loss of vision ("wipe-out") in the early post-operative period after glaucoma-filtration surgery in advanced glaucoma. Methods: It was a prospective, interventional cohort study. Patients with advanced glaucoma and macular split fixation underwent either only trabeculectomy (group A) or combined phaco-emulsification with trabeculectomy (group B). The incidence and cause of visual loss, changes in intra-ocular pressure, visual acuity, and visual field indices during 2 months post surgery were assessed. Results: Thirty patients (30 eyes) were divided in two groups. No significant difference was noted between the pre-operative and post-operative mean deviations in both groups (P = 0.41, P = 0.65). Two eyes in group A and one eye in group B had visual loss of two lines or more at the end of 2 months because of cataract and choroidal detachment. None of the eyes showed "wipe-out". Conclusion: "Wipe-out" is a rare phenomenon after surgery in advanced glaucoma.

Late-stage ortho-C-H alkenylation of 2-arylindazoles in aqueous medium by Manganese(i)-catalysis.

Earth-abundant and water-tolerant manganese(i) catalyzed alkenylation of 2-arylindazole with alkyl and aryl alkynes through C-H bond activation is described with a unique level of E-selectivity. The reaction proceeds through the control of C3 nucleophilicity of 2-aryl indazoles. This method is applied to the late-stage functionalization of complex molecules including ethinylestradiol, norethisterone, and N-protected amino acid derivatives. The kinetic isotope studies suggest that the C-H bond activation step may not be the rate-determining step.

Study of COVID-19 epidemiological evolution in India with a multi-wave SIR model.

The global pandemic due to the outbreak of COVID-19 ravages the whole world for more than two years in which all the countries are suffering a lot since December 2019. In this article characteristics of a multi-wave SIR model have been studied which successfully explains the features of this pandemic waves in India. Origin of the multi-wave pattern in the solution of this model is explained. Stability of this model has been studied by identifying the equilibrium points as well as by finding the eigenvalues of the corresponding Jacobian matrices. In this model, a finite probability of the recovered people for becoming susceptible again is introduced which is found crucial for obtaining the oscillatory solution in other words. Which on the other hand incorporates the effect of new variants, like delta, omicron, etc in addition to the SARS-CoV-2 virus. The set of differential equations has been solved numerically in order to obtain the variation of susceptible, infected and removed populations with time. In this phenomenological study, some specific sets of parameters are chosen in order to explain the nonperiodic variation of infected population which is found necessary to capture the feature of epidemiological wave prevailing in India. The numerical estimations are compared with the actual cases along with the analytic results.

Clinical outcome of orbital apex syndrome in COVID associated mucormycosis patients in a tertiary care hospital.

AIM: To share clinical pattern of presentation, the modalities of surgical intervention and the one month post-surgical outcome of rhino-orbito-mucormycosis (ROCM) cases. METHODS: All COVID associated mucormycosis (CAM) patients underwent comprehensive multidisciplinary examination by ophthalmologist, otorhinolaryngologist and physician. Patients with clinical and radiological evidence of orbital apex involvement were included in the study. Appropriate medical and surgical intervention were done to each patient. Patients were followed up one-month post intervention. RESULTS: Out of 89 CAM patients, 31 (34.8%) had orbital apex syndrome. Sixty-six (74.2%) of such patients had pre-existing diabetes mellitus, 18 (58%) patients had prior documented use of steroid use, and 55 (61.8%) had no light perception (LP) presenting vision. Blepharoptosis, proptosis, complete ophthalmoplegia were common clinical findings. Seventeen (19.1%) of such patients had variable amount of cavernous sinus involvement. Endoscopic debridement of paranasal sinuses and orbit with or without eyelid sparing limited orbital exenteration was done in most cases, 34 (38.2%) patients could retain vision in the affected eye. CONCLUSION: Orbital apex involvement in CAM patients occur very fast. It not only leads to loss of vision but also sacrifice of the eyeball, orbital contents and eyelids. Early diagnosis and prompt intervention can preserve life, vision and spare mutilating surgeries.

Microscopic and Transcriptomic Analyses of Dalbergoid Legume Peanut Reveal a Divergent Evolution Leading to Nod-Factor-Dependent Epidermal Crack-Entry and Terminal Bacteroid Differentiation.

Root nodule symbiosis (RNS) is the pillar behind sustainable agriculture and plays a pivotal role in the environmental nitrogen cycle. Most of the genetic, molecular, and cell-biological knowledge on RNS comes from model legumes that exhibit a root-hair mode of bacterial infection, in contrast to the Dalbergoid legumes exhibiting crack-entry of rhizobia. As a step toward understanding this important group of legumes, we have combined microscopic analysis and temporal transcriptome to obtain a dynamic view of plant gene expression during Arachis hypogaea (peanut) nodule development. We generated comprehensive transcriptome data by mapping the reads to A. hypogaea, and two diploid progenitor genomes. Additionally, we performed BLAST searches to identify nodule-induced yet-to-be annotated peanut genes. Comparison between peanut, Medicago truncatula, Lotus japonicus, and Glycine max showed upregulation of 61 peanut orthologs among 111 tested known RNS-related genes, indicating conservation in mechanisms of nodule development among members of the Papilionoid family. Unlike model legumes, recruitment of class 1 phytoglobin-derived symbiotic hemoglobin (SymH) in peanut indicates diversification of oxygen-scavenging mechanisms in the Papilionoid family. Finally, the absence of cysteine-rich motif-1-containing nodule-specific cysteine-rich peptide (NCR) genes but the recruitment of defensin-like NCRs suggest a diverse molecular mechanism of terminal bacteroid differentiation. In summary, our work describes genetic conservation and diversification in legume-rhizobia symbiosis in the Papilionoid family, as well as among members of the Dalbergoid legumes.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Rhodium-Catalyzed Directed C(sp2)-H Bond Addition of 2-Arylindazoles to N-Sulfonylformaldimines and Activated Aldehydes.

Rhodium-catalyzed directed C-H functionalization of 2-arylindazoles with N-sulfonylformaldimines has been developed to provide a variety of N-benzylarylsulfonamide derivatives with good to excellent yields. Different activated aldehydes like ethyl glyoxalate and 2,2,2-trifluoroacetaldehyde also efficiently underwent nucleophilic addition with 2-arylindazoles. These selective transformations occur through the control of C3 nucleophilicity of indazole moiety. Mechanistic studies suggest that C-H activation step may be a rate-limiting step.

Fe(iii)-Catalyzed synthesis of steroidal imidazoheterocycles as potent antiproliferative agents.

An efficient and practical method has been developed for the synthesis of steroidal imidazoheterocycles via cost-effective and environmentally benign FeCl3-catalyzed oxidative amination. A library of steroidal imidazo[1,2-a]pyridines was directly synthesized from readily available 2-aminopyridines and steroidal ketones in aerobic conditions. The synthesized compounds were screened for activity on human microsomal cytochrome P450s CYP7, CYP17 and CYP21. Antiproliferative activity of two lead compounds 3ia and 3la was additionally evaluated against the human MCF-7 (breast cancer), SKOV3 (ovarian cancer), and 22Rv1 (prostate cancer) cell lines. Steroidal imidazo[1,2-a]pyridine 3la which is a substrate molecule for CYP17A1 with IC50 = 1.7 µM (MCF-7), 3.0 (SKOV3), and 6.0 µM (22Rv1) has proved to be more active than reference drug cisplatin.

Organophotoredox-Catalyzed Direct C-H Amination of 2H-Indazoles with Amines.

A general and practical method for the direct C-H amination of 2H-indazoles with a series of amines including aliphatic primary amines, secondary amines, azoles, and sulfoximines via organophotoredox-catalyzed oxidative coupling has been disclosed at room temperature under ambient air conditions. Additionally, this protocol is used for free aminated 2H-indazole synthesis. A mechanistic study revealed that a single electron transfer (SET) pathway might be involved in this reaction.

Exotic topological point and line nodes in the plaquette excitations of a frustrated Heisenberg antiferromagnet on the honeycomb lattice.

A number of topological nodes including Dirac, quadratic and three-band touching points as well as a pair of degenerate Dirac line nodes are found to emerge in the triplet plaquette excitations of the frustrated spin-1/2 J 1-J 2 antiferromagnetic Heisenberg honeycomb model when the ground state of the system lies in a spin-disordered plaquette-valence-bond-solid phase. A six-spin plaquette operator theory of this honeycomb model has been developed for this purpose by using the eigenstates of an isolated Heisenberg hexagonal plaquette. Spin-1/2 operators are thus expressed in the Fock space spanned by the plaquette operators those are obtained in terms of exact analytic form of eigenstates for a single frustrated Heisenberg hexagon. Ultimately, an effective interacting boson model of this system is obtained on the basis of low energy singlets and triplets plaquette operators by employing a mean-field approximation. The values of ground state energy and spin gap of this system have been estimated and the validity of this formalism has been tested upon comparison with the known results. Emergence of topological point and line nodes on the basis of spin-disordered ground state noted in this investigation is very rare on any frustrated system as well as the presence of triplet flat band. Evolution of those topological nodes is studied throughout the full frustrated regime. Finally, emergence of topological phases has been reported upon adding a time-reversal-symmetry breaking term to the Hamiltonian. Coexistence of spin gap with either topological nodes or phases turns this honeycomb model an interesting one.

Regioselective hydroarylation and arylation of maleimides with indazoles via a Rh(iii)-catalyzed C-H activation.

Switchable Rh(iii)-catalyzed highly regioselective hydroarylation and oxidative arylation of maleimides with 2-arylindazoles via C-H activation have been demonstrated. The reaction affords 3-(2-(2H-indazol-2-yl)phenyl)succinimide and 3-(2-(2H-indazol-2-yl)phenyl)maleimide derivatives in high yields with wide functional group tolerance. A mechanistic study was performed to depict C-H bond cleavage that might be involved in the turnover limiting step.

Dioxygen-Triggered Oxo-Sulfonylation of Hydrazones.

A simple and highly efficient method for the oxo-sulfonylation of aldehyde-derived hydrazones has been developed using sulfinic acid as a source of sulfonyl group and oxygen as a green oxidant under metal-free conditions at room temperature. The present C-O and N-S bond-forming difunctionalization strategy affords diversely functionalized N-acylsulfonamides in good yield. Experimental results suggest a radical mechanistic pathway of the present reaction.

Tunable wavevector filtering in borophane based normal metal-barrier-normal metal junctions.

We study the transport properties of Dirac electrons across a two-dimensional normal metal-barrier-normal metal interface in monolayer borophane. We analyse the transmission probability with variation of the width of the barrier region, the incidence energy and transverse momentum. We demonstrate that a gap exists in the transmission probability spectrum and the position of the width of the transmission gap can be tuned by the barrier strength and transverse momentum respectively. We point out the variation of the ballistic tunneling conductance as a function of the width of the barrier region and incident energy. We find that the oscillatory or decaying nature of the conductance with variation in barrier width depends upon the number of propagating and evanescent modes which are controlled by the incident energy and barrier strength. We show that the conductance as a function of incident energy drops to a minimum value when the incident energy becomes identical to the barrier height and identify that this effect is caused by the presence of evanescent modes inside the barrier. Based on these findings we propose a perfectly tunable wavevector filter for borophane. We expect our findings possess useful applications in borophane based nano-electronic devices.

First and second order topological phases on ferromagnetic breathing kagome lattice.

In this work, topological properties of a ferromagnetic Heisenberg model on a breathing kagome lattice are investigated extensively in the presence of Dzyaloshinskii-Moriya interaction. While the kagome ferromagnet hosts only a single first order topological phase, the breathing kagome system exhibits multiple first and second order topological phases along with their coexistence. Magnon dispersion relation is obtained by using linear spin wave theory. Flat band and Dirac cones are obtained in the absence of Dzyaloshinskii-Moriya interaction. A topological phase diagram is presented where several first and second order phases as well as their overlap are identified. Values of thermal Hall conductivity for all the first order phases are obtained. Distinct first order phases are characterized by different sets of Chern numbers in association with the necessary chiral edge states in accordance to the first order bulk-boundary-correspondence rule. Second order phase is characterized by polarization along with the emergence of corner states. Violation of the second order bulk-corner-correspondence rule has been noted in some regions.