Disposable Screen‐Printed Carbon Electrodes for Dual Electrochemiluminescence/Amperometric Detection: Sequential Injection Analysis of Oxalate

This work describes the development and application of an electrochemical cell specifically designed for disposable screen printed carbon electrodes (SPCE) suitable for simultaneous electrochemiluminescence (ECL) and amperometric detection in sequential injection analysis. The flow system with facility for photomultiplier tube via a fiber optic facing the SPCE is user‐friendly and makes the detection process very easy to operate. Instead of the need to constant deliver the chemiluminescence (CL) reagents to the reaction zone, sequential injection analysis allows a considerable reduction in the consumption of the sample and expensive CL reagents (such as Ru(bpy) salts). The utility of the analyzer was demonstrated for the detection of oxalate based on the ECL reaction with Ru(bpy) . Under optimized conditions, in the presence of 100 μM Ru(bpy) , the linear ranges of peak current and ECL light intensity for oxalate distinctly varied from 10 μM to 5 mM and 0.1 μM to 100 μM, respectively. In other words, the linear detection can be covered over a four‐order range with the combination of these two signals.     

Unexpected Self‐Sorting Self‐Assembly Formation of a [4:4] Sulfate:Ligand Cage from a Preorganized Tripodal Urea Ligand

The design and synthesis of tripodal ligands 1 – 3 based upon the N‐methyl‐1,3,5‐benzenetricarboxamide platform appended with three aryl urea arms is reported. This ligand platform gives rise to highly preorganized structures and is ideally suited for binding SO₄^2? and H₂PO₄^? ions through multiple hydrogen‐bonding interactions. The solid‐state crystal structures of 1 – 3 with SO₄^2? show the encapsulation of a single anion within a cage structure, whereas the crystal structure of 1 with H₂PO₄^? showed that two anions are encapsulated. We further demonstrate that ligand 4 , based on the same platform but consisting of two bis‐urea moieties and a single ammonium moiety, also recognizes SO₄^2? to form a self‐assembled capsule with [4:4] SO₄^2?: 4 stoichiometry in which the anions are clustered within a cavity formed by the four ligands. This is the first example of a self‐sorting self‐assembled capsule where four tetrahedrally arranged SO₄^2? ions are embedded within a hydrophobic cavity.     

Double O-H insertion reactions of cyclic rhodium carbenoids: diastereoselective synthesis of macrocyclic oxindoles

Double O-H insertion reactions of cyclic diazo amides 1 and dihydroxy compounds 2 in the presence of rhodium(II) acetate catalyst have been achieved, which ultimately led to the facile synthesis of prototype bis(3-oxy-1,3-dihydro-2H-indol-2-one) systems. This facile double O-H insertion reaction protocol was successfully applied to synthesize several C₂-symmetric macrocycles having oxindole units incorporated with complete diastereoselectivity.     

Ocimum basilicum L. Methanol Extract Enhances Mitochondrial Efficiency and Decreases Adipokine Levels in Maturing Adipocytes Which Regulate Macrophage Systemic Inflammation

Excessive storage of lipids in visceral or ectopic sites stimulates adipokine production, which attracts macrophages. This process determines the pro- and anti-inflammatory response regulation in adipose tissue during obesity-associated systemic inflammation. The present study aimed to identify the composition of Ocimum basilicum L. (basil) seed extract and to determine its bio-efficacy on adipocyte thermogenesis or fatty acid oxidation and inhibition of lipid accumulation and adipokine secretion. Ocimum basilicum L. seed methanol extract (BSME) was utilized to analyze the cytotoxicity vs. control; lipid accumulation assay (oil red O and Nile red staining), adipogenesis and mitochondrial-thermogenesis-related gene expression vs. vehicle control were analyzed by PCR assay. In addition, vehicle control and BSME-treated adipocytes condition media were collected and treated with lipopolysaccharide (LPS)-induced macrophage to identify the macrophage polarization. The results shown that the active components present in BSME did not produce significant cytotoxicity in preadipocytes or macrophages in the MTT assay. Furthermore, oil red O and Nile red staining assay confirmed that 80 and 160 μg/dL concentrations of BSME effectively arrested lipid accumulation and inhibited adipocyte maturation, when compared with tea polyphenols. Gene expression level of adipocyte hyperplasia (CEBPα, PPARγ) and lipogenesis (LPL)-related genes have been significantly (p ≤ 0.05) downregulated, and mitochondrial-thermogenesis-associated genes (PPARγc1α, UCP-1, prdm16) have been significantly (p ≤ 0.001) upregulated. The BSME-treated, maturing, adipocyte-secreted proteins were detected with a decreased protein level of leptin, TNF-α, IL-6 and STAT-6, which are associated with insulin resistance and macrophage recruitment. The “LPS-stimulated macrophage” treated with “BSME-treated adipocytes condition media”, shown with significant (p ≤ 0.001) decrease in metabolic-inflammation-related proteins—such as PGE-2, MCP-1, TNF-α and NF-κB—were majorly associated with the development of foam cell formation and progression of atherosclerotic lesion. The present findings concluded that the availability of active principles in basil seed effectively inhibit adipocyte hypertrophy, macrophage polarization, and the inflammation associated with insulin resistance and thrombosis development. Ocimum basilicum L. seed may be useful as a dietary supplement to enhance fatty acid oxidation, which aids in overcoming metabolic complications.     

Improved random graph isomorphism

Canonical labeling of a graph consists of assigning a unique label to each vertex such that the labels are invariant under isomorphism. Such a labeling can be used to solve the graph isomorphism problem. We give a simple, linear time, high probability algorithm for the canonical labeling of a G(n,p) random graph for p[ω(ln⁴n/nlnlnn),1−ω(ln⁴n/nlnlnn)]. Our result covers a gap in the range of p in which no algorithm was known to work with high probability. Together with a previous result by Bollobás, the random graph isomorphism problem can be solved efficiently for p[Θ(lnn/n),1−Θ(lnn/n)].     

Direct Electrocatalytic Oxidation of Cysteine and Cystine Based on Nafion/Lead Oxide‐Manganese Oxide Combined Catalyst

This article reports direct electrocatalytic oxidation of cysteine (CySH) and cystine (CyS‐SCy) at an inexpensive Nafion/lead oxide‐manganese oxide combined catalyst in physiological pH. The synthesized lead oxide‐manganese oxide material is simply mixed with Nafion in the form of cast solution and modified on a disposable screen‐printed carbon electrode (designated as SPE/Nf‐PMO) for biosensing application. Electrochemical study with a standard redox couple of quinone/hydroquinone demonstrates an enhanced current response at the combined catalyst compared to its individual component. Surface characterization further provides information regarding the structural morphology of the catalyst to its catalytic performance. Direct electrocatalytic oxidation signals are observed at +0.75 and +1.20 V vs. Ag/AgCl for cysteine and cystine, respectively, at the SPE/Nf‐PMO. To extend the applicability, we further apply the proposed system for the detection of cysteine and cystine by flow injection analysis (FIA). Under optimized conditions, the detection limit (S/N=3) is 0.43 μM and 0.33 μM for cysteine and cystine, respectively.     

Lattice Effects on the Spin‐Crossover Profile of a Mononuclear Manganese(III) Cation

Six solvated salts of a mononuclear manganese(III) complex with a chelating hexadentate Schiff base ligand are reported. One member of the series, [MnL]PF₆^.0.5 CH₃OH ( 1 ), shows a rare low‐spin (LS) electronic configuration between 10–300 K. The remaining five salts, [MnL]NO₃? C₂H₅OH ( 2 ), [MnL]BF₄?C₂H₅OH ( 3 ), [MnL]CF₃SO₃?C₂H₅OH ( 4 ), [MnL]ClO₄?C₂H₅OH ( 5 ) and [MnL]ClO₄?0.5 CH₃CN ( 6 ), all show gradual incomplete spin‐crossover (SCO) behaviour. The structures of all were determined at 100 K, and also at 293 K in the case of 3 – 6 . The LS salt [MnL]PF₆^.0.5 CH₃OH is the only member of the series that does not exhibit strong hydrogen bonding. At 100 K two of the four SCO complexes ( 2 and 4 ) assemble into 1D hydrogen‐bonded chains, which weaken or rupture on warming. The remaining SCO complexes 3 , 5 and 6 do not form 1D hydrogen‐bonded chains, but instead exhibit discrete hydrogen bonding between cation/counterion, cation/solvent or counterion/solvent and show no significant change on warming.     

Synthesis of triazolo indazolones using 3D mesoporous aluminosilicate catalyst with nanocage structure

Mesoporous Aluminosilicate (AlKIT-5) has been found to be an efficient catalyst for one-pot synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives from dimedone, urazole, and aromatic aldehydes using acetonitrile as a solvent. This new method is simple, effective, ecofriendly, and consistently has the advantage of excellent yields (80-96%) and short reaction time (30-60 min). The effect of the catalyst weight, aluminum content in the catalyst, and the solvents on the synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives has been investigated. It has been found that the catalyst can be recycled for several times without much affecting its activity for a variety of organic transformations.     

Studies on strontium substituted rare earth manganites

Sintering, electrical conductivity and thermal expansion behaviour of combustion synthesised strontium substituted rare earth manganites with the general formula Ln_1−xSr_xMnO₃ (Ln=Pr, Nd and Sm; x=0, 0.16 and 0.25) have been investigated as solid oxide fuel cell cathode materials. The combustion derived rare earth manganites have surface area in the range of 13–40 m²/g. Strontium substitution increases the electrical conductivity values in all the rare earth manganites. With the decreasing ionic radii of rare earth ions, the conductivity value decreases. Among the rare earth manganites studied, (Pr/Nd)_0.75Sr_0.25MnO₃ show high electrical conductivity (>100 S/cm). The thermal expansion coefficients of Pr_0.75Sr_0.25MnO₃ and Nd_0.75Sr_0.25MnO₃ were found to be 10.2×10⁻⁶ and 10.7×10⁻⁶ K⁻¹ respectively, which is very close to that of the electrolyte (YSZ) used in solid oxide fuel cells.