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N- functionalized aziridines, which are both useful intermediates and important synthetic targets, can be envisioned as arising from the addition of nitrenes ( i.e ., NR fragments) to olefinic substrates. The exceptional reactivity of most nitrenes, in particular with respect to unimolecular decomposition, prevents general application of nitrene-transfer to the synthesis of N -functionalized aziridines. Here we demonstrate N -aryl aziridine synthesis via 1) olefin aziridination with N -aminopyridinium reagents to afford N -pyridinium aziridines followed by 2) Ni-catalyzed C–N cross-coupling of the N -pyridinium aziridines with aryl boronic acids. The N -pyridinium aziridine intermediates also participate in ring-opening chemistry with a variety of nucleophiles to afford 1,2-aminofunctionalization products. Mechanistic investigations indicate aziridine cross-coupling proceeds via a noncanonical mechanism involving initial aziridine opening promoted by the bromide counterion of the Ni catalyst, C–N cross-coupling, and finally aziridine reclosure. Together, these results provide new opportunities to achieve selective incorporation of generic aryl nitrene equivalents in organic molecules. Aziridines are useful intermediates, present in important synthetic targets. Here, the authors show a strategy for the synthesis of N-aryl aziridines based on N-aminopyridinium reagents followed by Ni-catalyzed C–N cross-coupling of N-pyridinium aziridines with aryl boronic acids.

The development of sustainable oxidation chemistry demands strategies to harness O2 as a terminal oxidant. Oxidase catalysis, in which O2 serves as a chemical oxidant without necessitating incorporation of oxygen into reaction products, would allow diverse substrate functionalization chemistry to be coupled to O2 reduction. Direct O2 utilization suffers from intrinsic challenges imposed by the triplet ground state of O2 and the disparate electron inventories of four-electron O2 reduction and two-electron substrate oxidation. Here, we generate hypervalent iodine reagents--a broadly useful class of selective two-electron oxidants--from O2 . This is achieved by intercepting reactive intermediates of aldehyde autoxidation to aerobically generate hypervalent iodine reagents for a broad array of substrate oxidation reactions. The use of aryl iodides as mediators of aerobic oxidation underpins an oxidase catalysis platform that couples substrate oxidation directly to O2 reduction. We anticipate that aerobically generated hypervalent iodine reagents will expand the scope of aerobic oxidation chemistry in chemical synthesis.

Maxillary central incisor is considered the tooth with least anatomical variations. In literature, the prevalence of single root and single canal in maxillary central incisor has been reported as 100%. Only a handful of case reports suggesting more than one root or one canal are available and are mostly associated with developmental anomalies such as gemination and fusion. This article describes a rare case report of retreatment of a maxillary central incisor with two roots with normal clinical crown which was confirmed by cone-beam computer tomography (CBCT). A 50-year-old Indian male patient presented with pain and discomfort on a root canal-treated anterior tooth. Pulp sensibility testing of left maxillary central incisor was negative. Intraoral periapical digital radiograph revealed an obturated canal with suspected outline of a second root which got confirmed with cone shift technique. The tooth was treated under dental operating microscope during which two canals were located and retreatment was completed. Postobturation, CBCT was performed to study the root and canal morphology. Clinically and radiographically, all the follow-up examinations revealed an asymptomatic tooth without any active periapical lesion. The present case report emphasizes the fact that clinicians should approach each case with an open mind having a thorough knowledge of the normal tooth anatomy and should suspect variations in every case to ensure successful endodontic outcome.

Design of sustainable synthetic methods for oxidation reactions is one of the fundamental challenges in chemistry, and both aerobic conditions and electrochemistry provide attractive means to carry out sustainable oxidation reactions. Biological C–H oxidation catalysis routinely proceeds via highly reactive oxidized metal sites generated from O₂; similar oxidation reactions are usually carried out in contemporary synthesis using O₂ surrogates such as hypervalent iodinereagents. These reagents are often used in stoichiometric quantities leading to poor atom economy. In 2018, we reported the development of aerobic hypervalent iodine catalysis predicated on diverting aldehyde autoxidation intermediates towards the oxidation of aryl iodides for sustainable synthesis of both I(III) and I(V) reagents. Many of the transformations for which hypervalent iodine intermediates have been developed, including a-functionalization of carbonyls and metal-free C–H/N–H cross-coupling reactions, were successfully carried out aerobically. We discovered that aryl iodides with weakly-coordinating 2-substituted groups (such as tert-butylsulfonyl) yielded the corresponding I(V) reagents due to disproportionation of initially formed I(III) derivatives under the autoxidation reaction conditions and leveraged that for aerobic alcohol oxidation chemistry. Under autoxidation conditions, 1,2-diols afforded alcohol oxidation accompanied with C–C bond cleavage — characteristic of Dess-Martin Periodinane (DMP). Thus, this discovery serves as the first example of aerobic oxidation catalysis involving DMP analogue.Detailed mechanistic studies of the aerobic oxidation chemistry led to identification of facile one-electron oxidation and the development of electrocatalytic hypervalent iodine chemistry. We demonstrated the viability of hypervalent iodine electrocatalysis in the context of both intra- and intermolecular C–H amination reactions, forming carbazole and aromatic hydrazine derivatives, respectively via iodanyl radical catalysis. To expand the scope of amination reactions, we have developed new class of N-aminopyridinium reagents through benzyl C–H aminopyridylation, and utilized in the synthesis of tetrahydroisoquinolines and a-aminated carbonyl compounds.Finally, a new family of aminating reagents, based on N-aminopyridinium scaffolds, were developed in response to the oxidative lability of many amine precursors under the strongly oxidizing conditions required for iodine-centered oxidation.Given the breadth of chemistry available for hypervalent iodine compounds, demonstration of strategies to facilitate the aerobic and electrochemical generation of hypervalent iodine species promises to significantly impact the sustainable use of hypervalent iodine intermediates in synthesis.

Aim: To compare dentinal cracks incidences after root canal preparation using Hand K-files; Rotary files: Protaper NEXT (PTN), Hyflex Controlled Memory (CM); and Reciprocating files: Wave One and Wave One Gold files. Materials and Methods: Hundred extracted human mandibular first premolars with straight root canals were taken postextraction and were allocated randomly into five groups (n = 20 teeth per group). The canals were instrumented using Hand K-files, Protaper Next (PTN), Hyflex CM, Wave One, and Wave One Gold systems. Group 1-Control group comprised of canals prepared by Hand files. Further, the roots were sectioned at three levels: 3, 6, and 9 mm horizontally from the apex using a saw at a low-speed saw and under water cooling. These slices were examined under a stereomicroscope at 25× magnification and the presence of any dentinal cracks was noted. The frequency of cracks was presented in number and percentage. Intergroup comparison of crack frequency was performed using analysis of variance. Results: No cracks were observed in the control group. In all the other groups, dentinal cracks were observed. The rotary files PTN and Hyflex CM files produced significantly fewer dentinal cracks than the reciprocating Wave One and Wave One Gold files (P < 0.05). The reciprocating files significantly produced more cracks apically than the rotary files (P < 0.05). Analyses were performed on SPSS software (windows version 22.0). Conclusion: Instrumentation with file systems can cause crack formation in the dentinal wall of the root canal. Determination of which files to choose for root canal preparation is technique sensitive and each instrument type has own benefits. However, care should be taken while biomechanical preparation to avoid dentinal cracks formation.

Nutritive value of five Cenchrus ciliaris (buffel grass) genotypes (IG96-50, IG96-96, IG96-358, IG96-401 and IG96-403) weredetermined. Their sugar contents (>70 mg/g of dry matter) and ensiling potential were evaluated using in vitro batch culture and in vivo studies. Research indicated significant differences ( P < 0 . 05 ) in the dry matter, organic matter, ether extract, neutral detergent fiber, acid detergent fiber, cellulose and lignin contents of the C . ciliaris genotypes tested. Genotypes also differed ( P < 0 . 05 ) in total carbohydrates, structural carbohydrates, non-structural carbohydrates and protein fractions. Genotype IG96-96 had the lowest total digestible nutrients, digestible energy and metabolizable energy contents (377.2 g/kg, 6.95 and 5.71 MJ/kg of dry matter, respectively), and net energy values for lactation, maintenance and growth. After 45 days of ensiling, C . ciliaris silages differed ( P < 0 . 05 ) in dry matter, pH, and lactic acid contents, and their values ranged between 255–339, 4.06–5.17 g/kg of dry matter and 10.8–28.0 g/kg of dry matter, respectively. Maize silage had higher ( P < 0 . 05 ) Organic Matter (919.5g/kg of dry matter), ether extract (20.4g/kg of dry matter) and hemi-cellulose (272.3 g/kg of dry matter) than IG96-401 and IG96-96 silages. The total carbohydrates and non-structural carbohydrates of maize silage were higher ( P < 0 . 05 ), while structural carbohydrates were comparable ( P < 0 . 05 ) with C . ciliaris silages. Sheep on maize silage had ( P < 0 . 05 ) higher metabolizable energy, lower crude protein, and digestible crude protein intake (g/kg of dry matter) than those on C . ciliaris silage diets. Nitrogen intake and urinary-N excretion were higher ( P < 0 . 05 ) on genotype IG96-96 silage diet. Overall, this study suggested that certain C . ciliaris genotypes, notably IG96-401 and IG96-96, exhibited nutritive values comparable to maize silage in sheep studies, offering a promising avenue for future exploration as potential alternatives in diversified and sustainable livestock nutrition programs.

Ecosystem services (ES) provision and variation over spatial scales in agricultural land are often the result of interactions between agricultural management and ecological structures. Our goal was to evaluate the effect of conservation agriculture (CA) and conventional tillage (CT) practices on different ES and ecosystem disservices (DES) to evaluate their spatial variability, and to develop a new index to determine the sustainability of CA and CT systems in farmers’ fields. Under conservation agriculture and conventional tillage, the ecosystem services supplied by wheat-based cropping systems was measured, and the inverse distance weighted (IDW) interpolation technique was used to create maps of spatial variability. A new index, i.e., ecosystem service sustainability index (ESSI) was developed to assess the sustainability of the study area. The gain in food was higher in some parts of the Nilokheri and Taraori villages of Karnal district, where CA was practiced over the years. The gain in regulating service, i.e., SOC stock in the study area ranged between 1.99 and 5.54 Mg ha –1 . The study revealed approximately 178% increase in supporting service, i.e., soil formation in Nilokheri block over the study area. The ESSI of Karnal ranged between 1.48 and 7.60, and for Kaithal district it was between 1.22 and 6.24. In the study area, 67 villages were reported as degraded, 28 villages as vulnerable, 38 villages as sustainable but input intensive, 17 villages as sustainable. By incorporating ecosystem service concepts into conservation agriculture, wheat agroecosystems can be transformed into more robust and sustainable production systems.

A heterogeneous and magnetically recyclable Ni–chitosan nanocatalyst was synthesized and thoroughly characterized by powder Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, etc. It was effectively utilized in the eco-friendly synthesis of new C5–C6-unsubstituted 1,4-DHPs under ultrasonic irradiation. The important focus of the methodology was to develop an environmentally friendly protocol with a short reaction time and a simple reaction procedure. The other advantages of this protocol are a wide substrate scope, a very good product yield, the use of an eco-friendly solvent and a recyclable nanocatalyst, as well as reaction at room temperature.

Despite the suppression of human immunodeficiency virus (HIV) replication by combined antiretroviral therapy (cART), 50–60% of HIV-infected patients suffer from HIV-associated neurocognitive disorders (HAND). Studies are uncovering the role of extracellular vesicles (EVs), especially exosomes, in the central nervous system (CNS) due to HIV infection. We investigated links among circulating plasma exosomal (crExo) proteins and neuropathogenesis in simian/human immunodeficiency virus (SHIV)-infected rhesus macaques (RM) and HIV-infected and cART treated patients (Patient-Exo). Isolated EVs from SHIV-infected (SHIV-Exo) and uninfected (CTL-Exo) RM were predominantly exosomes (particle size < 150 nm). Proteomic analysis quantified 5654 proteins, of which 236 proteins (~4%) were significantly, differentially expressed (DE) between SHIV-/CTL-Exo. Interestingly, different CNS cell specific markers were abundantly expressed in crExo. Proteins involved in latent viral reactivation, neuroinflammation, neuropathology-associated interactive as well as signaling molecules were expressed at significantly higher levels in SHIV-Exo than CTL-Exo. However, proteins involved in mitochondrial biogenesis, ATP production, autophagy, endocytosis, exocytosis, and cytoskeleton organization were significantly less expressed in SHIV-Exo than CTL-Exo. Interestingly, proteins involved in oxidative stress, mitochondrial biogenesis, ATP production, and autophagy were significantly downregulated in primary human brain microvascular endothelial cells exposed with HIV+/cART+ Patient-Exo. We showed that Patient-Exo significantly increased blood–brain barrier permeability, possibly due to loss of platelet endothelial cell adhesion molecule-1 protein and actin cytoskeleton structure. Our novel findings suggest that circulating exosomal proteins expressed CNS cell markers—possibly associated with viral reactivation and neuropathogenesis—that may elucidate the etiology of HAND.

Nutritive value of five Cenchrus ciliaris (buffel grass) genotypes (IG96-50, IG96-96, IG96-358, IG96-401 and IG96-403) weredetermined. Their sugar contents (>70 mg/g of dry matter) and ensiling potential were evaluated using in vitro batch culture and in vivo studies. Research indicated significant differences (P < 0.05) in the dry matter, organic matter, ether extract, neutral detergent fiber, acid detergent fiber, cellulose and lignin contents of the C. ciliaris genotypes tested. Genotypes also differed (P < 0.05) in total carbohydrates, structural carbohydrates, non-structural carbohydrates and protein fractions. Genotype IG96-96 had the lowest total digestible nutrients, digestible energy and metabolizable energy contents (377.2 g/kg, 6.95 and 5.71 MJ/kg of dry matter, respectively), and net energy values for lactation, maintenance and growth. After 45 days of ensiling, C. ciliaris silages differed (P < 0.05) in dry matter, pH, and lactic acid contents, and their values ranged between 255-339, 4.06-5.17 g/kg of dry matter and 10.8-28.0 g/kg of dry matter, respectively. Maize silage had higher (P < 0.05) Organic Matter (919.5g/kg of dry matter), ether extract (20.4g/kg of dry matter) and hemi-cellulose (272.3 g/kg of dry matter) than IG96-401 and IG96-96 silages. The total carbohydrates and non-structural carbohydrates of maize silage were higher (P < 0.05), while structural carbohydrates were comparable (P < 0.05) with C. ciliaris silages. Sheep on maize silage had (P < 0.05) higher metabolizable energy, lower crude protein, and digestible crude protein intake (g/kg of dry matter) than those on C. ciliaris silage diets. Nitrogen intake and urinary-N excretion were higher (P < 0.05) on genotype IG96-96 silage diet. Overall, this study suggested that certain C. ciliaris genotypes, notably IG96-401 and IG96-96, exhibited nutritive values comparable to maize silage in sheep studies, offering a promising avenue for future exploration as potential alternatives in diversified and sustainable livestock nutrition programs.