Lipidomic analysis of twenty-seven prostanoids and isoprostanes by liquid chromatography/electrospray tandem mass spectrometry

Prostanoids are potent mediators of many physiological and pathophysiological processes. Of the many analytical methodologies used for their qualitative and quantitative analysis, electrospray tandem mass spectrometry coupled to liquid chromatography (LC/ESI-MS/MS) offers a rapid, sensitive and versatile system applicable to lipidomic analyses. We have developed an LC/ESI-MS/MS assay for twenty-seven mediators including prostaglandins, prostacyclines, thromboxanes, dihydroprostaglandins and isoprostanes. The assay was liner over the concentration range 1-100 pg/microL. The limits of detection and quantitation were 0.5-50 and 2-100 pg, respectively, whilst recoveries were from 83-116% depending on the metabolite. The assay can be applied to the profiling of prostanoids produced by a variety of biological fluids and extracts including brain, liver, plasma and urine, thus facilitating our understanding of the role of these lipid mediators in health and disease, as well as assisting in drug development.     

Universality of Coproducts in Categories of Lax Algebras

Categories of lax -algebras are shown to have pullback-stable coproducts if preserves inverse images. The general result not only gives a common proof of this property in many topological categories but also shows that important topological categories, like the category of uniform spaces, are not presentable as a category of lax -algebras, with preserving inverse images. Moreover, we show that any such category of -algebras has a concrete, coproduct preserving functor into the category of topological spaces.     

Simultaneous determination of tryptophan, uric acid and ascorbic acid at iron(III) doped zeolite modified carbon paste electrode

A new chemically modified electrode is constructed based on iron(III) doped zeolite modified carbon paste electrode (Fe(3+)Y/ZCME). The electrode was evaluated as a sensor for sub-micromolar determination of tryptophan (Trp), uric acid (UA) and ascorbic acid (AA) in aqueous solutions. The measurements were carried out by application of the differential pulse voltammetry (DPV) method in phosphate buffer solution with pH 3.5. Iron(III) loaded in zeolite can increase anodic peak currents by adsorption of Trp, UA and AA on electrode surface The analytical performance was evaluated with respect to the carbon paste composition, pH of solution, accumulation time and accumulation potential. The prepared electrode shows voltammetric responses with high sensitivity and selectivity for Trp, UA and AA in optimal conditions, which makes it very suitable for simultaneous determination of these compounds. The linear calibration range for AA in the presence of 50muM UA and 50muM Trp was 0.6muM to 100muM, with a correlation coefficient of 0.9992, and a detection limit of 0.21muM (S/N=3). A linear relationship was found for UA in the range of 0.3-700muM containing 10muM AA and 50muM Trp, with a correlation coefficient of 0.9990 and a detection limit of 0.08muM. The linear calibration range for Trp in the presence of 10muM AA and 50muM UA was 0.2-150muM, with a correlation coefficient of 0.9996, and a detection limit of 0.06muM. The proposed method was successfully applied for determination Trp, UA and AA in biological systems and pharmaceutical samples.     

(Benzyl isocyanide)gold(I) pyrimidine‐2‐thiolate complex: Synthesis and biological activity

The reaction of [(Me₂S)AuCl] with an equimolar amount of benzyl isocyanide (PhCH₂NC) ligand led to the formation of complex [(PhCH₂NC)AuCl] ( 1 ). The solid‐state structure of 1 was determined using the X‐ray diffraction method. Through a salt metathesis reaction, the chloride ligand in 1 was replaced by pyrimidine‐2‐thiolate (SpyN^?) to afford the complex [(PhCH₂NC)Au(η¹‐S‐Spy)] ( 2 ), which was characterized spectroscopically. The cytotoxic activities of 1 and 2 were evaluated against three human cancer cell lines: ovarian carcinoma (SKOV3), lung carcinoma (A549) and breast carcinoma (MCF‐7). Complex 2 showed higher cytotoxicity than cisplatin against SKOV3 and MCF‐7 cancer cell lines. It showed a strong anti‐proliferative activity with IC₅₀ of 7.80, 6.26 and 6.14 μM, compared with that measured for cisplatin which was 7.62, 12.36 and 11.47 μM, against A549, SKOV3 and MCF‐7 cell lines, respectively. The induction of cellular apoptosis by 2 was also studied on MCF‐7 cell line. Our results indicated that 2 could induce apoptosis in cancerous cells in a dose‐dependent manner.     

Synthesis of MnO2/CdTiO3 nano‐structure for high performance photocatalysis and antimicrobial application

A MnO₂/CdTiO₃ is prepared by a simple chemical method. The organic compound such as antibiotics is a contaminant found in large amounts in pharmaceutical industrial wastewater. Pharmaceutical compounds are toxic. The nano‐product was characterized by SEM, XRD, XPS, DLS and UV–vis DRS revealed that the MnO₂ nanoparticles were supported on the CdTiO₃ surface. The crystallite size was found as 72.11 nm, and 38.13 nm for CdTiO₃, and MnCdTi‐1 nanocomposites, respectively. The prepared catalyst was used for photo‐degradation of cephalexin under UV light irradiation. The result implies the complete degradation of cephalexin was carried out at 80 min for MnCdTi‐2 nanocomposites (88.88%) due to this catalyst has the lowest band gap compared to the other catalyst. The MnO₂/CdTiO₃ was selected for fungicidal and bactericidal efficiency against Aspergillus flavus, and candida albicans and Escherichia coli, and Staphylococcus aureus. The MnO₂/CdTiO₃–2 has great activity is compared with the other MnO₂/CdTiO₃–0 and MnO₂/CdTiO₃–1 samples.     

FeCl_3: Highly Efficient Catalyst for Synthesis of α-Amino Nitriles

α‐Amino nitriles are synthesized by the three‐component coupling reaction of aldehydes, amines and trimethylsilyl cyanide using FeCl₃ as a solid acid catalyst, under solvent‐free conditions in good yields. The catalyst was recovered by simple filtration and was recycled in subsequent reactions.     

Lewis Acidity of Carbon in Activated Carbonyl Group vs. B(C6F5)3 for Metal-Free Catalysis of Hydrogenation of Carbonyl Compounds

In this work, using DFT calculations, we investigated Lewis acidities of carbon (in activated carbonyl group) in comparison to the B(C₆F₅)₃ in combination with dioxane as the Lewis base (LB) for metal-free catalysis of heterolytic H₂ splitting and hydrogenation of carbonyl compounds. We found that in case of carbon as the Lewis acid (LA) the reaction is controlled by frontier molecular orbital interactions between the H₂ and LA-LB fragments at shorter distances. The steric effects can be reduced by electrophilic substitutions on the carbonyl carbon. Synergic combination between stronger orbital interactions and reduced steric effects can lower the barrier of the H₂ splitting below 10 kcal/mol. With the B(C₆F₅)₃, the H₂ splitting is controlled by electrostatic interactions, which cause to form an early transition state. An advantage of employing Lewis acidity of the activated carbonyl carbon for hydrogenation is that the hydride-type attack and hydrogenation of the C=O bond occur in a single step throughout H₂ splitting. Hence, stronger Lewis acidity of the C(C=O) reinforces hydrogenation without prohibition of the hydride delivery.     

Glycomics and glycoproteomics: Approaches to address isomeric separation of glycans and glycopeptides

Changes in the glycome of human proteins and cells are associated with the progression of multiple diseases such as Alzheimer's, diabetes mellitus, many types of cancer, and those caused by viruses. Consequently, several studies have shown essential modifications to the isomeric glycan moieties for diseases in different stages. However, the elucidation of extensive isomeric glycan profiles remains challenging because of the lack of analytical techniques with sufficient resolution power to separate all glycan and glycopeptide iso‐forms. Therefore, the development of sensitive and accurate approaches for the characterization of all the isomeric forms of glycans and glycopeptides is essential to tracking the progression of pathology in glycoprotein‐related diseases. This review describes the isomeric separation achievements reported in glycomics and glycoproteomics in the last decade. It focuses on the mass spectrometry–based analytical strategies, stationary phases, and derivatization techniques that have been developed to enhance the separation mechanisms in liquid chromatography systems and the detection capabilities of mass spectrometry systems.