Rhinosporidiosis of Conjunctiva: A Rare Presentation

Abstract Rhinosporidiosis is a chronic and localized infection of the mucous membrane of nose and paranasal sinuses caused by Rhinosporidium seeberi which is endemic in several parts of India particularly south India but it is rare in north eastern part of India. Ocular rhinosporidiosis is rare with less than 15 % of total cases. It usually presents as polypoidial mass and may mimic clinically as papilloma therefore histopathological diagnosis is crucial for correct diagnosis and treatment. We present a rare case of ocular rhinosporidiosis presenting as a polypoid conjunctival mass from Silchar, Barak valley region of north eastern India

Spintronics on Demand: Optically Tunable Kondo-Type Phenomena in Germanene-Azobenzene Single-Molecule Junctions

This study delves into the exploration of AZB–germanene composite systems, which are known for their intriguing characteristics, including the emergence of Kondo features and the precise manipulation of electronic spin induced by light exposure. The spin-polarized signature within trans-AZB exerts a significant influence on the band structure near the Fermi level, highlighting the critical role of conformational changes within the AZB component in regulating the magnetoelectronic coupling within the composite system. The research systematically analyzed the intricate interplay of electronic states within these systems with a specific focus on the potential observation of Kondo-like resonance in the trans-AZB–Ge system, resulting in the development of a spin-polarized electronic current within the junction. Theoretical insights suggest that the presence of a Kondo-like effect has the potential to significantly impact the electronic and magnetic properties of the system, making it a promising avenue for precise electronic control within the field of molecular electronics

An Iminosemiquinone-Coordinated Oxidovanadium(V) Complex: A Combined Experimental and Computational Study

Ligand H₄Sar^(AP/AP) contained two terminal amidophenolate units that were connected by a disulfane bridge. The ligand reacted with VOSO₄·5H₂O in the presence of Et₃N under air and provided a mononuclear octahedral oxidovanadium complex (<b>1</b>). X-ray crystal structure analysis of complex <b>1</b> revealed that the oxidation state of the V ion was V and the VO³⁺ unit was coordinated to an iminosemiquinone radical anion. An isotopic signal at <i>g</i> = 1.998 in the X-band electron paramagnetic resonance (EPR) spectrum and the solution magnetic moment μ_eff = 1.98 μ_B at 298 K also supported the composition. The formation of complex <b>1</b> preceded through the initial generation of a diamagnetic VO²⁺–iminoisemiquinone species, as established by time-dependent UV–vis–near-IR (NIR), X-band EPR, and density functional theory studies. The UV–vis–NIR spectrum of complex <b>1</b> consisted of four ligand-to-metal charge-transfer transitions in the visible region, while an intervalence ligand-to-ligand charge transfer appeared at 1162 nm. The cyclic voltammogram of the complex showed four oxidation waves and one reduction wave. Spectroelectrochemical studies at fixed potentials revealed that the oxidation and reduction processes were ligand-based

Highly Selective Detection of H⁺ and OH^– with a Single-Emissive Iridium(III) Complex: A Mild Approach to Conversion of Non-AIEE to AIEE Complex

A greenish-blue emissive bis-cyclometalated iridium­(III) complex with octahedral geometry was synthesized in a convenient route where a bulky substituted ligand, <i>N</i>¹<b>-</b>tritylethane-1,2-diamine ligand (trityl-based rotating unit) (<b>L</b>_<b>1</b>), was coordinated to iridium­(III) in nonchelating mode, [Ir­(F₂ppy)₂(L₁)­(Cl)], [F₂ppy = 2-(2′,4′-difluoro)­phenylpyridine; <b>L</b>_<b>1</b> = <i>N</i>¹-tritylethane-1,2-diamine], <b>1</b>. The purpose of introducing a rotor in <b>1</b> was anticipated to initiate aggregation-induced emission (AIE) activity in it. The presence of a secondary amine in <b>L</b>_<b>1</b> has attributed to <b>1</b> the ability to sense acids. The mechanism of this change in <b>1</b> under acidic medium was explored. A bright yellow emissive complex was formed on exposing <b>1</b> to hydroxide ion, which was isolated, characterized, and identified as a new aggregation-induced enhanced emission (AIEE) active complex. The detection limit of hydroxide ion was determined to 126 nM. Ground- and excited-state properties of <b>1</b> were investigated using DFT- and TD-DFT-based calculations, and several important aspects of the experimental facts were validated

Highly Selective Detection of H⁺ and OH^– with a Single-Emissive Iridium(III) Complex: A Mild Approach to Conversion of Non-AIEE to AIEE Complex

A greenish-blue emissive bis-cyclometalated iridium­(III) complex with octahedral geometry was synthesized in a convenient route where a bulky substituted ligand, <i>N</i>¹<b>-</b>tritylethane-1,2-diamine ligand (trityl-based rotating unit) (<b>L</b>_<b>1</b>), was coordinated to iridium­(III) in nonchelating mode, [Ir­(F₂ppy)₂(L₁)­(Cl)], [F₂ppy = 2-(2′,4′-difluoro)­phenylpyridine; <b>L</b>_<b>1</b> = <i>N</i>¹-tritylethane-1,2-diamine], <b>1</b>. The purpose of introducing a rotor in <b>1</b> was anticipated to initiate aggregation-induced emission (AIE) activity in it. The presence of a secondary amine in <b>L</b>_<b>1</b> has attributed to <b>1</b> the ability to sense acids. The mechanism of this change in <b>1</b> under acidic medium was explored. A bright yellow emissive complex was formed on exposing <b>1</b> to hydroxide ion, which was isolated, characterized, and identified as a new aggregation-induced enhanced emission (AIEE) active complex. The detection limit of hydroxide ion was determined to 126 nM. Ground- and excited-state properties of <b>1</b> were investigated using DFT- and TD-DFT-based calculations, and several important aspects of the experimental facts were validated

A Bis(Aquated) Mn(II)-Based MRI Contrast Agent with a Rigid Hydroquinazoline Unit: Synthesis, Characterization, and <i>in Vivo</i> MR Imaging Study

Since the finding of nephrogenic systemic fibrosis (NFS) in patients with renal impairment and the long-term accumulation of Gd(III) ions in the central nervous system, the search for nongadolinium ion-based MRI contrast agents made of nutrient metal ions has drawn paramount attention. In this context, the development of Mn(II)-based MRI contrast agents has been a subject of interest for the last few decades. Herein, we report a pentadentate ligand (Li2[BenzPic2]) composed of two picolinate moieties and a rigid 1,2,3,4-tetrahydroquinazoline unit and the corresponding bis(aquated) Mn(II) complex (Complex 1). The complex exhibited high thermodynamic stability (log Kcond = 11.62) and kinetic inertness similar to that of the clinically approved Gd(III)-based contrast agent Magnevist. Complex 1 exerted longitudinal relaxivity (r1) of 5.32 mM–1 s–1 at 1.41 T, 37 °C, pH 7.4, and it increased by 3.6-fold in the presence of serum albumin protein, confirming a substantial rigidifying interaction (albumin association constant KA = 1.66 × 103 M–1) between the protein and the amphiphilic (log P = −0.45) contrast agent. An intravenous dose of 0.08 mmol/kg in a healthy mouse, excellent MRI signal intensity enhancement in the vasculature of the mouse liver, and brightened images of the gallbladder, kidney, and liver were realized

A New Bis(aquated) High Relaxivity Mn(II) Complex as an Alternative to Gd(III)-Based MRI Contrast Agent

Disclosed here are a piperazine, a pyridine, and two carboxylate groups containing pentadentate ligand H₂pmpa and its corresponding water-soluble Mn­(II) complex (<b>1</b>). DFT-based structural optimization implied that the complex had pentagonal bipyramidal geometry where the axial positions were occupied by two water molecules, and the equatorial plane was constituted by the ligand ON₃O donor set. Thus, a bis­(aquated) disc-like Mn­(II) complex has been synthesized. The complex showed higher stability compared with Mn­(II)–EDTA complex [log<i>K</i>_MnL = 14.29(3)] and showed a very high <i>r</i>₁ relaxivity value of 5.88 mM^–1 s^–1 at 1.41 T, 25 °C, and pH = 7.4. The relaxivity value remained almost unaffected by the pH of the medium in the range of 6–10. Although the presence of 200 equiv of fluoride and bicarbonate anions did not affect the relaxivity value appreciably, an increase in the value was noticed in the presence of phosphate anion due to slow tumbling of the complex. Cell viability measurements, as well as phantom MR images using clinical MRI imager, consolidated the possible candidature of complex <b>1</b> as a positive contrast agent