Proteomic Analysis of Plasma Proteins in Diabetic Rats by 2D Electrophoresis and MALDI-TOF-MS

Despite tremendous advances in our understanding of the molecular basis of diabetes mellitus, substantial gaps still remain in our understanding of disease pathogenesis and in the development of effective strategies for early diagnosis and treatment. The proteomic approach has offered many opportunities and challenges in identifying new marker proteins and therapeutic targets, i.e., using 2D-polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry. The differential protein expressions were analyzed in alloxan-induced diabetic rats treated with Cynodon dactylon leaf extract. The plant extract was administered for 15 days that resulted in a significant increase in plasma insulin and C-peptide levels. We have also identified four differentially expressed proteins from rat plasma. These four diabetes-associated proteins were broadly classified into three groups as per their function: (1) lipid metabolism-associated protein (Apo A-IV), (2) antioxidant activity-related proteins [preprohaptoglobin and heat shock proteins B8 (HspB8)], and (3) muscle function-related protein (TPM3). Apo A-IV, HspB8, and preprohaptoglobin may play a key role in the recovery of diabetes mellitus and also prevent the diabetes-associated complications such as prevention of oxidative stress due to free radical and free hemoglobin. These results show the value of proteomic approach in identifying the potential markers that may eventually serve as diagnostic markers or therapeutic targets.     

A rapid and highly sensitive method for the determination of glimepiride in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry: application to a pre-clinical pharmacokinetic study

A sensitive and specific liquid chromatography-positive electrospray ionization-tandem mass spectrometry method has been developed and validated for the determination of glimepiride (GPD) in human plasma. GPD and the internal standard (IS, glibenclamide) were extracted from a small aliquot of human plasma (200 microL) by a simple liquid-liquid extraction technique using ethyl acetate as extraction solvent. The compounds were separated on a YMC Propack, C18, 4.6x50 mm column using a mixture of ammonium acetate buffer, acetonitrile and methanol (30:60:10, v/v) as mobile phase at 0.5 mL/min on an API 4000 Sciex mass spectrometer connected to an Agilent HPLC system. Method validation and pre-clinical sample analysis was performed as per FDA guidelines and the results met the acceptance criteria. GPD and IS were detected without any interference from human plasma matrix. The method was proved to be accurate and precise at linearity range of 0.02-100.00 ng/mL with a correlation coefficient of 0.999. The method was robust with a lower limit of quantitation of 0.02 ng/mL. Intra- and inter-day accuracies for GPD were 88.60-113.50 and 96.82-103.93%, respectively. The inter-day precision was better than 12.21%. This method enabled faster and reliable determination of GPD in a pre-clinical study.     

Electrochemical Activation of Graphite Nanosheets Decorated with Palladium Nanoparticles for High Performance Amperometric Hydrazine Sensor

Herein, we have demonstrated a preparation of palladium nanoparticles on electroactivated graphite nanosheets modified screen printed carbon electrode (PdNPs‐EGNS/SPCE) by a simple electrochemical method. The well‐prepared electrocatalyst was potentially applied to the high performance electrocatalytic oxidation of hydrazine in neutral medium. The PdNPs‐EGNS novel composite was characterized by scanning electron microscope (SEM) and the average diameter and thickness of PdNPs and EGNS were found to be ～38 nm and 85 nm, respectively. The high performance electrocatalytic determination of hydrazine was performed by the amperometric i‐t method. The fabricated sensor displayed irreversible electrocatalytic oxidation of hydrazine with diffusion‐controlled electrode process. The oxidation of hydrazine at PdNPs‐EGNS/SPCE showed wider linear range 0.05–1415 µM and high sensitivity 4.382 µA µM^?1 cm^?2. The as‐prepared electrocatalyst achieved quick response towards hydrazine with a lower detection limit 4 nM.     

Thin films of discotic liquid crystals and their applications

ABSTRACT

Discotic liquid crystals (DLCs) are considered as fascinating systems due to their unique property of self-assembly to yield different columnar structures. DLCs are organic semiconductors and create pathways for the development of numerous optical and electrical devices. The thin films of DLCs can be considered as low dimensional system which can exhibit remarkable optical and physical properties. In this article, we present a review on ultrathin films of some interesting DLC molecules at air–water and air–solid interfaces. The Langmuir monolayer and Langmuir–Blodgett films of DLC molecules are extensively studied. The ultrathin films of DLC molecules can yield highly anisotropic layer wherein the molecular orientation and aggregation can have large impact on the physicochemical properties of the film. Different surface phases with different molecular orientations as function of surface density and temperature can be obtained by forming the Langmuir monolayer of the DLC molecules at the air–water interface. The Langmuir monolayer in a particular phase can be deposited onto the active area of a device layer-by-layer by employing a highly controlled Langmuir–Blodgett technique. Here, we report some interesting results related on molecular orientation of the DLC molecules at different interfaces. Such aggregation of DLC molecules in ultrathin films may find applications in thin film-based electro-optical devices.     

Phenylene‐Bridged Core‐Modified Planar Aromatic Octaphyrin: Aromaticity,Photophysical and Anion Receptor Properties

The synthesis of a planar expanded meso porphyrin with an intramolecular para‐phenylene‐bridged core is reported. The planarity of the octaphyrin macrocycle was confirmed by single‐crystal X‐ray structural analysis, in which the bridged para‐phenylene unit deviated by 27° from the mean macrocyclic plane. Spectroscopic analyses and theoretical calculations suggested that the macrocycle was Hückel aromatic and followed a major [34 π] single‐conjugation pathway, which indicated that the bridging para‐phenylene unit was not involved in the macrocyclic conjugation. Analysis of the photophysical properties of this system by steady‐state absorption/fluorescence spectroscopy and transient absorption spectroscopy revealed moderate enhancement in the parameters of the octaphyrin as compared to its non‐bridged octaphyrin congeners, which was attributed to the planarity and rigidity of the macrocycle as imposed by the bridging para‐phenylene unit. Preliminary anion‐binding studies revealed that the protonated macrocycle bound selectively with chloride ions through N?H???Cl hydrogen‐bonding interactions.     

Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents: Synthesis through C?H Activation and Orthogonal Reactivity

(Pinacolato)boryl ortho‐silyl(hetero)aryl triflates are presented as a new class of building blocks for arylation. They demonstrate unique versatility by delivering boronate or (hetero)aryne reactivity chemoselectively in a broad range of transformations. This approach enables the unprecedented postfunctionalization of fluoride‐activated (hetero)aryne precursors, for example, as substrates in transition‐metal catalysis, and offers valuable new possibilities for aryl boronate postfunctionalization without the use of specialized protecting groups.     

Determination and assessment of the contents of essential and potentially toxic elements in Ayurvedic medicine formulations by inductively coupled plasma-optical emission spectrometry

Traditional Ayurvedic remedies are easily available nowadays not only in India, their country of origin, but also in Western countries. Some of these products contain high concentrations of potentially toxic elements as main or secondary ingredients, in addition to elements essential for human health; for these reasons, it is interesting to determine their elemental composition. In this study we assessed the concentrations of fifteen elements (Al, As, Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Pb, Si and Zn) in five products of the Parpati family, a group of Ayurvedic medicines containing high concentrations of mercury, manufactured in various places in India. Concentrations were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) or (for Pb and Cd) by graphite furnace atomic absorption spectrometry (GF-AAS) after sample mineralization. We compared the calculated daily intake of each element with reference values, considering maximum tolerable intake levels or recommended nutrient amounts. The experimental results were treated with chemometric pattern recognition techniques. We found differences in the composition of products of the same denomination manufactured by different companies and strong correlations among groups of variables. As expected, the daily intake of mercury upon consumption of Parpati medicines largely exceeded the tolerable intake level of this element.     

Solubilization of thermotropic liquid crystal compounds in aqueous surfactant solutions

We study the micellar solubilization of three thermotropic liquid crystal compounds by immersing single drops in aqueous solutions of the ionic surfactant tetradecyltrimethylammonium bromide. For both nematic and isotropic drops, we observe a linear decrease of the drop size with time as well as convective flows and self-propelled motions. The solubilization is accompanied by the appearance of small aqueous droplets within the nematic or isotropic drop. At low temperatures, nematic drops expell small nematic droplets into the aqueous environment. Smectic drops show the spontaneous formation of filament-like structures which resemble the myelin figures observed in lyotropic lamellar systems. In all cases, the liquid crystal drops become completely solubilized, provided the weight fraction of the liquid crystal in the system is not larger than a few percent. The solubilization of the liquid crystal drops is compared with earlier studies of the solubilization of alkanes in ionic surfactant solutions.