An Amperometric Immunosensor for IgG Based on Conducting Polymer and Carbon Nanotube‐Linked Hydrazine Label

An amperometric immunosensor for IgG was developed by covalently immobilizing anti‐IgG on multiwall carbon nanotube‐embedded conducting polymer, poly‐5,2′ : 5′′,2′′‐terthiophene‐3′‐carboxylic acid (MWCNT/pTTCA). The MWCNT/pTTCA modified electrode was characterized by SEM, EIS, and XPS. A hydrazine‐labeled secondary antibody‐MWCNT conjugate (Hyd‐MWCNT‐Ab₂) was applied for detection. Hydrazine was used as a catalyst for the reduction of hydrogen peroxide, which was monitored at ?0.3 V vs. Ag/AgCl. The calibration plots showed a linear range of 0.1–10 ng/mL with a detection limit of 0.084±0.004 ng/mL. The proposed immunosensor was evaluated for clinical applications in a rabbit serum sample.     

Catalytic asymmetric Payne oxidation under the catalysis of P-spiro chiral triaminoiminophosphorane: application to the synthesis of N-sulfonyl oxaziridines

The studies on the development of a highly enantioselective oxidation of N-sulfonyl imines with hydrogen peroxide–trichloroacetonitrile system utilizing P-spiro chiral triaminoiminophosphoranes as an organic base catalyst are detailed. This method is general and scalable, and exhibits unique chemoselectivity, providing a practical stereoselective route to structurally diverse N-sulfonyl oxaziridines. The mechanistic investigations reveal that the reaction proceeds through the Payne-type oxidation pathway. The synthetic utility of the optically active N-sulfonyl oxaziridines as versatile organic oxidants and chiral building blocks is also demonstrated.     

Hydrophilic interaction chromatography‐tandem mass spectrometric analysis of irbesartan in human plasma: Application to pharmacokinetic study of irbesartan

A hydrophilic interaction chromatography‐tandem mass spectrometric method (HILIC/MS/MS) for the determination of irbesartan in human plasma was developed. Irbesartan and losartan (internal standard) were extracted from human plasma with ethyl acetate at acidic pH. The analytes were analyzed on a Luna HILIC column with the mobile phase of ACN–ammonium formate (50 mM, pH 6.5) (96:4, v/v) and detected by ESI MS/MS in the selected reaction monitoring mode. The standard curve was linear (r² = 0.9981) over the concentration range of 10–2500 ng/mL and the lower LOQ was 10 ng/mL using 100 μL of plasma sample. The CV and relative error for intra‐ and interassay at four QC levels were 2.9 to 8.1% and –2.7 to 2.3%, respectively. There were less absolute and relative matrix effects for irbesartan and losartan. The present method was successfully applied to the pharmacokinetic study of irbesartan after oral dose of irbesartan (150 mg tablet) to male healthy volunteers.     

Synthesis of α‐Stereogenic Amides and Ketones by Enantioselective Conjugate Addition of 1,4‐Dicarbonyl But‐2‐enes

Constructing α‐stereogenic amides and ketones : The highly regioselective and enantioselective conjugate addition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).

     

Iron(III) Located in the Dinuclear Metallo‐β‐Lactamase IMP‐1 by Pseudocontact Shifts

Heterodinuclear metalloenzymes are an important class of metalloproteins, but determining the location of the different metal ions can be difficult. Herein we present a new NMR spectroscopy method that uses pseudocontact shifts (PCS) to achieve this without assumptions about the coordinating ligands. The approach is illustrated with the dinuclear [FeZn] complex of IMP‐1, which is a prototypical metallo‐β‐lactamase (MβL) that confers resistance to β‐lactam antibiotics. Results from single‐crystal X‐ray diffraction were compromised by degradation during crystallization. With [GaZn]‐IMP‐1 as diamagnetic reference, the PCSs unambiguously identified the iron binding site in fresh samples of [FeZn]‐IMP‐1, even though the two metal centers are less than 3.8 Å apart and the iron is high‐spin Fe³⁺, which produces only small PCSs. [FeZn]‐MβLs may be important drug targets, as [FeZn]‐IMP‐1 is enzymatically active and readily produced in the presence of small amounts of Fe³⁺.     

The Role of Internal Droplet Size on Emulsion Stability and the Extraction Performance of Kraft Lignin Removal from Pulping Wastewater in Emulsion Liquid Membrane Process

It has been discovered that the size of internal droplets in primary emulsion determines emulsion dispersion and stability in emulsion liquid membrane (ELM) process for removal of lignin from pulping wastewater. Generally, primary emulsion contains kerosene, Aliquat 336, sodium bicarbonate, as well as Span 80 as diluent, carrier, internal phase, and surfactant, respectively. Hence, this study had looked into the parameters, including concentration of surfactant, carrier, and stripping agent; emulsification speed and time; as well as agitation speed and time. As a result, the diameter of the smallest droplets (1.4 µm) was formed with maximum lignin extraction (95%), minimum swelling (5%) at 3% (w/v) surfactant concentration, 12,000 rpm of emulsification within 5 minutes, 0.01 M of Aliquat 336, 0.1 M of NaHCO_3, and 250 rpm of extraction within 10 minutes.     

Five-Fold Symmetric Pentaindolo- and Pentakis(benzoindolo)Corannulenes: Unique Structural Dynamics Derived from the Combination of Helical and Bowl Inversions

Peripherally π-extended corannulenes bearing quintuple azahelicene units, 10 and 11 , were prepared and their dynamic behaviors were studied experimentally and theoretically. The fused corannulenes were synthesized from sym-pentabromocorannulene in three steps. X-Ray diffraction analysis for 10 displayed a conformer possessing a P(M) bowl chirality and a PPMPM (PMPMM) helical chirality, which was found to be the most stable conformer(s). Variable-temperature NMR measurements of 10 and 11 revealed that their structural isomers can be interconvertible in solution, depending on the steric congestion around the helical scaffolds. Automated search for conformers in the equilibrium and transition states by Artificial Force Induced Reaction (AFIR) method revealed their interconversion networks, including bowl-inversion and helical-inversion. This analysis indicated that the co-existing corannulene and azahelicene moieties influence the conformational dynamics, which leads to mitigation of the activation energy barriers for isomerization.     

What Is the Mechanism Driving the Reduction of Cardiovascular Events from Glucagon-like Peptide-1 Receptor Agonists?—A Mini Review

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are considered the standard of care for type 2 diabetes in many countries worldwide. These molecules have profound anti-hyperglycaemic actions with a favourable safety profile. They are now being considered for their robust cardiovascular (CV) protective qualities in diabetic patients. Most recent CV outcome trials have reported that GLP-1 RAs reduce major adverse cardiovascular events (MACE). Furthermore, the GLP-1 RAs seem to target the atherosclerotic CV disease processes preferentially. GLP-1 RAs also improve a wide range of routinely measured surrogate markers associated with CV risk. However, mediation analysis suggests these modest improvements may contribute indirectly to the overall anti-atherogenic profile of the molecules but fall short in accounting for the significant reduction in MACE. This review explores the body of literature to understand the possible mechanisms that contribute to the CV protective profile of GLP-1 RAs.