Macro- and microtechnological studies on beechwood panels bonded with Pinus brutia bark tannin

The suitability of hot water extracted tannins from the bark of Pinus brutia from Turkey as a binder either alone or in combination with phenol formaldehyde was examined. Using formaldehyde-hydrochloric acid about 77% of the active phenolic components could be precipitated. Because of the high molecular weights of the polyphenols only small amounts of formaldehyde were necessary for a complete curing. On the basis of the tannin along with a hardener, such as paraformaldehyde or hexamethylenetetramine, boiling-water-resistant gluing of beechwood panels was obtained (DIN 53254, DIN 68602). Electron microscopical and microanalytical studies of such tannin-bonded panels showed the localization of the adhesive, penetration of the adhesive into the wood cells as well as the interaction between the tannin adhesive and the wood cell walls.     

SUPERCRITICAL FLUID EXTRACTION OF TURKISH LIGNITES AND OIL SHALE WITH TOLUENE MIXTURES

Abstract

Supercritical -Fluid extraction (SFE) of two Turkish lignites and oil shale with toluene mixtures were investigated. Experiments were performed in a batch autoclave at 623 K. Extracts recovered from SFE were fractionated into oils, asphaltenes and preasphal-tenes by solvent extraction.

The conversion of lignites decreased with increasing n-pentane content in the mixture. The extraction yield and the products (oils, AS, PAS) increased with increasing n-pentane content in its range below 15 %

The conversion and the extract yield obtained from Cöynük ail shale is higher with toluene mixture than toluene.     

Antimicrobial poly(N‐vinyl‐2‐pyrrolidone‐alt‐maleic anhydride)/poly(ethylene imine) macrocomplexes

The antimicrobial polymer/polymer macrocomplexes were synthesized by radical alternating copolymerization of N‐vinyl‐2‐pyrrolidone with maleic anhydride [poly(VP‐alt‐MA)] with 2,2′‐azobis‐isobutyronitrile as an initiator at 65°C in dioxane solutions under nitrogen atmosphere, and interaction of prepared copolymer with poly(ethylene imine) (PEI) in aqueous solutions. The susceptibility of some Gram‐negative (Salmonella enteritidis and Escherichia coli) and Gram‐positive (Staphylococcus aureus and Listeria monocytogenes) bacteria to the alternating copolymer and its PEI macrocomplexes with different compositions in microbiological medium was studied using pour‐plate technique. All the studied polymers, containing biologically active moieties in the form of ionized cyclic amide, and macrobranched aliphatic amine groups and acid/amine complexed fragments, were more effective against L. monocytogenes than those for Gram‐positive S. aureus bacterium. This fact was explained by different surface layer structural architectures of biomacromolecules of tested bacteria. The resulting polymeric antimicrobial materials are expected to be used in various areas of medicine and food industry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5841–5847, 2006     

Effects of ohmic thawing on histological and textural properties of beef cuts

The changes in the histology and the texture of beef cuts during ohmic thawing were compared with those during conventional thawing method. The beef cut samples were thawed from −18 to 10 °C by applying different voltage gradients (10, 20 and 30 V/cm) during ohmic treatment whereas conventional thawing was applied at constant temperature (25 °C, 95% RH) in the controlled incubator. There were significant differences between the effects of thawing methods in terms of hardness, chewiness, gumminess of beef cut samples (p < 0.05). The sample treated ohmically at 30 V/cm voltage gradient was significantly different from the other thawed samples in terms of springiness, cohesiveness and resilience (p < 0.05). The change in the textural properties was explained by investigating the histological changes of beef cuts for both thawing method. Ohmic thawing provided the thawed meat sample having lower textural and histological changes rather than conventionally thawed ones.     

Supercritical CO2 extraction of accumulated capsidiol from biotic elicitor‐activated Capsicum annuum L fruit tissues

This work investigates the supercritical CO₂ extraction of capsidiol from pepper fruit tissues activated with Alternaria alternate (Fr) Keissler suspension culture as a biotic elicitor. Capsidiol production in the fruit tissue was markedly increased by the treatment with a biotic elicitor and reached its maximum level after 4 days of elicitation. The effects of separation parameters such as temperature, pressure, supercritical solvent flow rate, particle diameter and also initial capsidiol concentration were investigated on solubility, initial extraction rate and extraction yield. The optimal extraction conditions were obtained at the temperature of 40 °C, the pressure of 400 bar, the supercritical CO₂ flow rate of 2 cm³ min^?1, and the average particle diameter of 116 µm. The results showed that the ratio of the supercritical CO₂ extraction yield to the organic solvent extraction yield was changed from 84 to 97 wt‐% depending on the initial capsidiol concentration. Copyright © 2004 Society of Chemical Industry     

Testing of Drug Release from Bioadhesive Vaginal Tablets

To establish en in vitro test method that can predict the drug release and dissolution behaviour of vaginal bioadhesive controlled release tablets, a system was developed and its appropriateness to the in situ conditions was examined. For this purpose, the dissolution rates of vaginal bioadhesive tablets were measured by three different methods. These were, USP dissolution apparatus two and a new vaginal dissolution tester (NVDT) which was developed by us with some modification of the vaginal tablet desentegration apparatus of BP 1988 and, testing in cow vaginas in situ. Four different bioadhesive tablet formulations were used being composed of the drug and the anionic polymer, polyacrylic acid (PAA) and the nonionic polymers, hydroxypropylmethyl cellulose (HPMC) and ethyIcellulose (EC). The release profiles of the in vitro and in situ methods were investigated and evaluated kinetically.

It was found that NVDT could be used to investigate the drug release from vaginal tablets.     

Synthesis,antibacterial and antifungal evaluation of thio- or piperazinyl-substituted 1,4-naphthoquinone derivatives

A series of S-, S,S-, S,O-, N- and N,S-derivatives from 2,3-dichloro-1,4-naphthoquinone compound 1 were synthesized in different reaction media and evaluated for their antibacterial and antifungal activities. The structures of the novel products were characterized by spectroscopic methods, such as microanalysis, ¹H NMR, ¹³C NMR and MS. Among the tested compounds 9, 12 and 18 are the most effective compounds against Candida tenuis as potent antifungal compounds. Compound 9 is also the most effective compound against Staphylococcus aureus as a potent antifungal compound.     

Untersuchung der Rinde von Pseudotsuga menziesii (Mirb.) Franco

Douglas-fir bark contains relatively high amounts of extractable material, the polyphenols of which are a suitable raw material for the preparation of heat-curing adhesives due to their low molecular weight distribution. Extraction of bark with petrol ether yields about 6% wax which consists mainly of esters of saturated long chain fatty acids and dicarboxylic acids with fatty alcohols. A total of nearly 60% of bark substance can be extracted. The content of holocellulose and Klason lignin in 25% and 16% respectively.     

Mikrobiologische Behandlung von Fichtenrinde-Heißwasserextrakten zur Herstellung von Leimharzen

Microbiological treatment of hot water extracts from Norway spruce bark can reduce their carbohydrate content. Thus adhesives can be produced from the polyphenols of these extracts with small additions of phenolic resin.