AZADIRACHTIN : ITS EFFECTS ON EGGS AND POSTEMBRYONIC DEVELOPMENT IN SPODOPTERA MAURITIA BOISD. (LEPIDOPTERA : NOCTUIDAE)

Eggs of Spodoptera mauritia of known ages (day 0, day 1 and day 2) were topically treated with 5µg, 10 µg or 20 µg azadirachtin and the effects of these treatments on hatchability and postembryonic development were studied. Treatments had no effect on egg hatchability, but the larvae showed high rate of mortality during postembryonic development. The significance of these findings is discussed

3D printing of modified soybean hull fiber/polymer composites

Herein, we have evaluated the soybean hull derived fibers as reinforcements to manufacture thermoplastic copolyester (TPC) composites using 3D printing process namely fused filament fabrication (FFF). The hulls were subjected to physical and chemical treatments to understand their influence on the microstructural and mechanical properties of the composites. We found strong dependence of surface quality, printing defects and interbead/interlayer bonding on the fiber treatment. The composites made using dilute acid hydrolysis treated fibers increased the relative density of the composites to 99% and reduced the pore size from 81 mu m to 39 mu m. Defect free fiber-matrix interfacial characteristics in these composites enhanced the elastic modulus from 36 MPa to 54 MPa. Similarly, the toughness and stress at 50% strain of these composites were similar to 30% and 50% higher than the pure TPC, respectively. Our results clearly demonstrated that the low-cost and abundantly available soybean hulls when modified using dilute acid hydrolysis have a strong potential in the fabrication of natural fiber reinforced composites

Additive manufacturing of natural fiber reinforced polymer composites: Processing and prospects

Throughout the world there have been alarming concerns over the use of nonrenewable resources during manufacturing of goods and associated environmental legislations. Therefore, the use of natural materials and fabrication of composites therefrom, particularly, development of natural fiber reinforced polymer composites is gaining significant attention. Although natural fiber reinforced composites (NFRCs) show strong application prospects, various materials and processing related challenges needs to be addressed to achieve long-term stability and performance. In this review, we attempted to provide an overview of different types of natural fibers, their characteristics and properties enabling them to be used as reinforcing agents in different polymers. Then the unique requirement of fiber surface modification to achieve enhanced fiber-matrix bonding is discussed. The article also discusses conventional processing routes and critical issues associated with NFRCs processing. The use of different additive manufacturing (AM) technologies in processing polymer composites is also discussed. At the end, we have critically analyzed the challenges and opportunities associated with AM of NFRCs

Syntheses and conformational studies on AZT and its deuterated analogues

The NMR spectrum of 3'-azido-3'-deoxythymidine (AZT) in aqueous solution provides sum of some of the proton-proton coupling constants. This limitation precludes the determination of the pseudorotational parameters of the sugar ring. Selective deuteration alleviates this problem. The synthesis of 2'-deutero and 3'-deutero- AZT have been described for the first time starting from D-xylose and β-thymidine respectively. NMR study of these analogues in aqueous solutions shows that almost equal amount of C-2'-endo and C-3'-endo species exist in equilibrium

LiBF<SUB>4</SUB>-catalyzed formation of fused pyrano- and furanobenzopyrans

Lithium tetrafluoroborate efficiently catalyzes an unusual cyclization of o-hydroxybenzaldimines with 2,3-dihydrofuran and 3,4-dihydro-2H-pyran at ambient temperature to afford a class of new pyrano- and furanobenzopyran derivatives in excellent yields with high diastereoselectivity

Chiral polyhydroxylated tetrahydrothiophene derivatives: Novel synthesis and structural elucidation by X-ray crystallography, NMR spectroscopy and molecular mechanics calculations

This article does not have an abstract

Isolation of C5-Sugars from the Hemicellulose-Rich Hydrolyzate of Distillers Dried Grains

A three-stage process for isolation and separation of C5-sugars in dry form from the hydrolyzate of distillers dried grains (DDG) is described. The salient features include extraction of bis­(boronic ester) adducts of xylose and arabinose into toluene on treatment of neutralized hydrolyzate with phenylboronic acid (PBA) and subsequent addition of propylene glycol to the organic phase to induce sugar precipitation for ready collection. The PBA used in the process is largely reclaimed on hydrolysis of the propylene glycol boronic ester formed during the process. A preparative scale example afforded 48% of the xylose content in DDG as a crystalline solid also containing an additional 11% of the arabinose content