HPTLC-Aided Phytochemical Fingerprinting Analysis as a Tool for Evaluation of Herbal Drugs. A Case Study of Ushaq (Ammoniacum Gum)

JPC – Journal of Planar Chromatography – Modern TLC - The phytochemical fingerprint profile of ammoniacum gum (from Dorema ammoniacum) was defined by subjecting different extracts of...     

Characterization of the E1′ center in quartz: Role of aluminum hole centers and oxygen vacancies

The growth of E₁′ centers in a variety of natural and synthetic quartz crystals has been investigated by employing the electron spin resonance technique. It has been reported that the growth of E₁′ centers, formed by irradiation and subsequent annealing at 300 °C for 15 min, scale with the concentration of the aluminum hole center, [AlO₄]⁰, till a limit. Later, the E₁′ centers show saturation even when the [AlO₄]⁰-center continues to grow. For quartz with low efficiency of the formation of [AlO₄]⁰-center or irradiated with low accumulated doses, the intensity of E₁′ center was small where not all oxygen vacancies are converted to the E₁′ center. Thus, besides the availability of a number of oxygen vacancy sites, the number of holes released from the [AlO₄]⁰-center plays an important role in the formation of E₁′ centers in quartz.     

Retail replenishment models with display-space elastic demand

We study a single store multi-product inventory problem in which product sales are a composite function of shelf space. Since sales tend to deplete the amount of product on display, the effective shelf space assigned to the product diminishes with time unless replenishment occurs. We consider the problem of optimal replenishment times under these conditions. We assume a linear dependence of sales rate to effective shelf space in all our analysis. We present exact and approximate solutions for the single product and multi-product cases. For the single product case, we study the effect of space elasticity, cross elasticity and empty space elasticity on the optimal replenishment period. For the multi-product case we present a computationally attractive method using matrix exponentials and develop error bounds for this method.     

Structural,morphological and photoluminescence characteristics of sol-gel derived nano phase CeO<Subscript>2</Subscript> films deposited using citric acid

Homogenous nano structured CeO₂ films have been prepared by a sol-gel process using different mole ratios of citric acid as additive. XPS studies clearly illustrate an increase in Ce³⁺ proportion upon the use of higher citric acid content for the deposition of films. The crystallite sizes in the films lie in the nanorange. Photoluminescence emission in the films is attributed to various defects resulting from crystallization. Lowest transparency, high Ce³⁺ content and optimum sized crystallites in CeO₂ (1:1.5) films have led to its highest PL characteristics. Ce³⁺ chemical state is the major contributor to the PL activity of these films. The SEM micrographs show a reduced level of CeO₂ agglomeration in the films deposited using higher citric acid contents. A comparison of different properties of CeO₂ films deposited using citric acid and CeO₂–TiO₂ films has also been made.      

Organic reactions in water: an efficient one-pot synthesis of acyloxiranes from Baylis-Hillman adducts using hypervalent iodine

Treatment of Baylis-Hillman adducts with iodosobenzene (PhIO) in the presence of a catalytic amount of KBr in water at room temperature afforded the corresponding acyloxiranes in good yields.     

Enantioselective total synthesis of bioactive natural product (+)-Sch 642305: a structurally novel inhibitor of bacterial DNA primase and HIV-1 Tat transactivation

The total synthesis of the bioactive natural product (+)-Sch 642305 has been achieved from a readily available chiral building block using an RCM protocol to construct the key decalactone moiety; our approach is notable for its built-in flexibility and is diversity oriented.     

Canine Parvovirus Type 2a (CPV-2a)-Induced Apoptosis in MDCK Involves Both Extrinsic and Intrinsic Pathways

The canine parvovirus type 2 (CPV-2) causes an acute disease in dogs. It has been found to induce cell cycle arrest and DNA damage leading to cellular lysis. In this paper, we evaluated the apoptotic potential of the “new CPV-2a” in MDCK cells and elucidated the mechanism of the induction of apoptosis. The exposure of MDCK cells to the virus was found to trigger apoptotic response. Apoptosis was confirmed by phosphatidylserine translocation, DNA fragmentation assays, and cell cycle analysis. Activation of caspases-3, -8, -9, and -12 and decrease in mitochondrial potential in CPV-2a-infected MDCK cells suggested that the CPV-2a-induced apoptosis is caspase dependent involving extrinsic, intrinsic, and endoplasmic reticulum pathways. Increase in p53 and Bax/Bcl2 ratio was also observed in CPV-2a-infected cells.     

The stereoselective total synthesis of PF1163A

A stereoselective total synthesis of 13-membered macrocycle PF1163A, an antifungal agent, has been accomplished for the first time starting from d-xylose. This approach involves a diastereoselective allylation of lactal ether,^3a reductive ring opening of tetrahydrofuran ring,^3b asymmetric methylation reaction, Yamaguchi esterification, and ring closing metathesis as key steps.