Existence, uniqueness and stability of random impulsive neutral partial differential equations

AbstractIn this paper, the existence, uniqueness and stability via continuous dependence of mild solution of neutral partial differential equations with random impulses are studied under sufficient condition via fixed point theory

A REVIEW ON MATRIX ASSISTED LASER DESORPTION/INOZATION MASS SPECTROSCOPY

ABSTRACTMatrix assisted laser desorption ionization mass spectroscopy (MALDI-MS) is the most important technique of MS to analyze polymer systems. It isa special case of MS using specific sample preparation methods and low fluence laser desorption to create the analyte ions. This technique is basedupon an ultraviolet absorbing matrix. The matrix and the polymer are mixed at a molecular level in an appropriate solvent. The solvent helps preventaggregation of the polymer. The sample matrix mixture is placed on the sample probe tip, under vacuum conditions; the solvent is removed, leaving cocrystallizedpolymer molecules homogenously dispersed within matrix molecules. When the pulsed laser beam is tuned to the appropriate frequency,the energy is transferred to the matrix which is partially vaporized, carrying intact polymer into the vapor phase and charging the polymer chains inthe linear time of flight (TOF) analyzer. This review includes the detailed information of MALDI-MS, MALDI-TOF.Keywords: Matrix assisted laser desorption ionization mass spectroscopy, Principle, Sample preparation techniques, Matrix assisted laser desorptionionization - time of flight, Matrix assisted laser desorption ionization - mass spectrometric imaging, Applications

Synthetic studies on a marine natural product, palmerolide A: Synthesis of C1-C9 and C15-C21 fragments

An efficient cross metathesis and Pd-catalyzed allylic rearrangement have been successfully used to construct the northern hemisphere of a cytotoxic marine natural product, palmerolide A

An expedient enyne metathesis approach to dysidiolide

A short and efficient enyne metathesis route is reported for the construction of a key intermediate required in the synthesis of dysidiolide thus completing its formal synthesis.© Elsevie

A Shimizu Non-Aldol Approach to the Formal Total Synthesis of Palmerolide A

A formal total synthesis of palmerolide A has been accomplished by assembling three fragments by means of successive Julia-Kocienski olefination, Yamaguchi esterification, and ring-closing metathesis (RCM). Our initial efforts to combine the first two fragments through a Julia-Kocienski reaction between a secondary sulfone and a ketone were not successful; nevertheless, it was feasible between a primary sulfone and aldehyde. Yamaguchi esterification with the third fragment then set the stage for a RCM reaction. Initial failure of the RCM with a PMB-ether adjacent to the olefins and the difficulty in cleaving the PMB-ether prompted us to change the choice of protecting groups, which then paved the way to the macrocyclic core of palmerolide A

Effect of aluminum doping on the structural, morphological, electrical and optical properties of ZnO thin films prepared by sol-gel dip coating

689-693Aluminum doped zinc oxide (AZO) thin films with 0-5 at.% aluminum content have been prepared by sol-gel dip coating technique. The thickness of the films has been measured using alpha step method. The structural and morphological properties have been studied, respectively, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Higher intensity zinc oxide (ZnO) peak (002) has been observed in 1 at.% aluminum doped film with 450 °C of annealing temperature. The grains are more densely packed in the films doped in 1 at.% aluminum content. The grains have tendency to decrease in size as the aluminum content increases. Electrical resistivity measurement technique reveals that electrical resistance decreases with increase of film thickness. The lowest resistivity of the AZO thin film is 3.2×10-2 Ω. Optical properties of AZO thin films are tested by UV-visible spectroscopy, while comparing with all the films 0.5 at.% aluminum doped film produces more than 90% of transmittance