The solvation of cellulose by the action of nitrogen tetroxide in organic solvents

This article reviews the solvation of cellulose by the action of N₂O₄ in presence of a suitable proton acceptor and its subsequent regeneration. The mechanism of the nitrosation reaction and the factors affecting cellulose degradation during solvation and regeneration are discussed. The possible industrial applications of this process as well as the use of cellulose nitrite in the preparation of novel cellulose derivatives are also included.     

Predicting performance of object recognition

We present a method for predicting fundamental performance of object recognition. We assume that both scene data and model objects are represented by 2D point features and a data/model match is evaluated using a vote-based criterion. The proposed method considers data distortion factors such as uncertainty, occlusion, and clutter, in addition to model similarity. This is unlike previous approaches, which consider only a subset of these factors. Performance is predicted in two stages. In the first stage, the similarity between every pair of model objects is captured by comparing their structures as a function of the relative transformation between them. In the second stage, the similarity information is used along with statistical models of the data-distortion factors to determine an upper bound on the probability of recognition error. This bound is directly used to determine a lower bound on the probability of correct recognition. The validity of the method is experimentally demonstrated using real synthetic aperture radar (SAR) data     

Effect of pre-gelatinised high-amylose maize starch combined with Ca2+ -induced setting of alginate on the physicochemical and sensory properties of rice flour noodles

This study explored the effect of pre-gelatinised high-amylose maize starch combined with Ca²⁺ -induced setting of alginate on the physicochemical and sensory properties of rice flour noodles. Rice flour noodles were prepared by partially substituting rice flour with pre-gelatinised high-amylose maize starch in ratios of 5, 10 and 15% (wt/wt), combined with sodium alginate at 1% (wt/wt). The noodles were then immersed in a calcium chloride solution to set the alginate. Results indicated that the hydrocolloids significantly (P < 0.05) increased noodle tensile strength, hardness, water absorption and optimum cooking time while cooking loss was significantly (P < 0.05) reduced. SEM micrographs showed a denser, compact noodle structure with an increase in the matrix's continuity as a result of hydrocolloids addition. Formulated noodles also scored above average (5.91) sensory acceptability on the 7 points hedonic scale. Overall, results proved promising for the preparation of rice flour noodles with enhanced properties.     

A new method for the purification of Egyptian cotton waste fibres

A new pulping method using sodium nitrate was successfully used for the purification of Egyptian cotton waste fibres. Sodium nitrate alone, sodium nitrate in nitric acid solution and sodium nitrate in sodium hydroxide solution were used in pulping. The chemical, physical and sub-microscopic characteristics of the pulps obtained and their reactivity towards xanthation were estimated. The best results were obtained when a mixture of sodium nitrate and nitric acid were used in pulping.     

Rate-distortion analysis of multiview coding in a DIBR framework

Depth image-based rendering techniques for multiview applications have been recently introduced for efficient view generation at arbitrary camera positions. The rate control in an encoder has thus to consider both texture and depth data. However, due to different structures of depth and texture data and their different roles on the rendered views, the allocation of the available bit budget between them requires a careful analysis. Information loss due to texture coding affects the value of pixels in synthesized views, while errors in depth information lead to a shift in objects or to unexpected patterns at their boundaries.In this paper, we address the problem of efficient bit allocation between texture and depth data of multiview sequences.We adopt a rate-distortion framework based on a simplified model of depth and texture images, which preserves the main features of depth and texture images. Unlike most recent solutions, our method avoids rendering at encoding time for distortion estimation so that the encoding complexity stays low. In addition to this, our model is independent of the underlying inpainting method that is used at the decoder for filling holes in the synthetic views. Extensive experiments validate our theoretical results and confirm the efficiency of our rate allocation strategy.     

Delivery of vinblastine-containing niosomes results in potent in vitro/in vivo cytotoxicity on tumor cells

Vinblastine (VB), as a chemotherapeutic agent, is widely used in treatment of different types of cancer. However, its clinical application is limited due to its low water solubility, side effects, and multidrug resistance. The aim of this study was to increase the therapeutic efficacy of VB using drug delivery systems. For this purpose, a PEGylated niosomal formulation of vinblastine (Pn-VB) was prepared by thin film hydration method and physicochemically characterized. Drug release pattern was performed by dialysis diffusion method. The cytotoxicity of Pn-VB was investigated against murine lung cancer TC-1 cells using MTT assay and its tumor inhibitory effect was evaluated in lung tumor-bearing C57BL/6 mice. Mean particle size, zeta potential, entrapment, and loading efficiency of niosomes were obtained to be about 234.3?±?11.4?nm, -34.6?±?4.2?mV, 99.92?±?1.6%, and 2.673?±?0.30%, respectively. While, the mean particle size and zeta potential for non-PEGylated niosomes were obtained about 212.4?nm and -31.4?mV, respectively. The in vitro release pattern of drug from niosomes showed a sustained release behavior. Pn-VB indicated a significant increase in toxicity against TC-l cells as compared to free VB. In animal model, Pn-VB exhibited stronger tumor inhibitory effect and longer life time in comparison to free VB. In conclusion, Pn-VB showed appropriate stability, high-entrapment efficacy, lower releasing rate, and stronger cytotoxic activity against lung cancer TC-1 cells as compared to free drug. Thus, the Pn-VB could be a promising formulation for delivery of vinblastine to tumor cells with enhanced drug bioavailability and therapeutic efficacy.     

Dissolving pulps from Egyptian bagasse. II. Low temperature cooking

Bagasse was pulped by the prehydrolysis-soda process. Increasing the concentration during prehydrolysis or pulping had a favourable effect on pulp properties. Further improvement in these properties was attained when the increase in concentration was accompanied by lowering the temperature. The effects of increasing the concentration and lowering the temperature of prehydrolysis and pulping were compared.     

Effect of gamma irradiation on pupal stage of Ephestia calidella (Guenée)

Mature pupae of Ephestia calidella (Guenée) were irradiated at doses of 200–1000 Gy. Variations in the percentage of adult emergence and percentage of malformed adults were used as criteria to evaluate the radiation effects. A dose of 1000 Gy prevented the emergence of both sexes. Females and males were sterilized with a dose of 350 and 400 Gy, respectively. Adult longevity and mating ability varied with regard to the dose. Males irradiated with sub-sterile doses (100, 150, and 200 Gy) were more sexually competitive with normal males than those irradiated with the sterilizing dose (400 Gy).     

Preparation and cyclisation reactions of 3-Carboxy-4-naphthylbut-3-enoic Acids

The condensation of naphthalene-1- or 2-carbaldehyde with dimethyl 2,2-dimethyl-succinate (Stobbe conditions) gives predominantly the ( Z )-hemiesters 3 and 11a . The hemiester 3 contains a small amount of the ( E )-isomer. Similar condensation of naphthalene-2-carbaldehyde with dimethyl-2-methylsuccinate gave the hemiester ( E )- 12a . Their configuration and the ratios of the ( Z:E )-hemiesters, their derived acids, anhydrides, indenones and phenanthrene derivatives are inferred by high resolution ¹H-n.m.r. spectroscopy.