Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 11

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  polysaccharides
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Peripheral nerve injuries are one of frequent cause of disability. Results of surgical procedures are not still completely satisfactory, though fast development of microsurgical technician improve their efficiency. One of the major problems in surgical treatment of the peripheral nerve injuries is ends coaptation in the case of large loss of nerve tissue. And so finding substitute implants not rejected by the organism for the recipient and providing with the success is necessary of regeneration. Recently, several synthetic nerve guide implants have been introduced and approved for clinical use to replace autologous transplants. This alternative therapy is based on pioneering studies with experimental nerve guides. This paper present a review of published studies involving biodegradable nerve guides.
2
100%
EN
Polysaccharides are macromolecular polymers that manifest ability toward the forming of fibres, film and coatings. Some of their specific properties like biodegradability and biocompatibility make them suitable for medical application. Chitin, chitosan and alginates are basic polymers mostly used in the preparation of medical biomaterials. In the Institute of Biopolymers and Chemical Fibres (IBWCh) multidirectional investigations are in full swing concerned with the use medical of polysaccharides and their various useful forms. The research includes amongst: multifunctional dressing materials, implants and other polysaccharide biomaterials.
EN
Presented herein are investigations in the preparation of an advanced , human-and environmentfriendly plant protection composition based on selected bioactive biopolymers of the polysaccharide family. In the Institute of Biopolymers and Chemical Fibres the biopolymers were prepared and the biological activity of chitosan in the form of salt and gel and of hemicelluloses (galactoglucomannans) and of their compositions was tentatively evaluated by way of plate tests. Estimated was the impact of such preparations upon the stimulation of the germination rate of radish seeds at concentration of 0.1, 0.01 and 0.005% after 72 hours. The efficacy of the preparations was evaluated based on the number of germinated seeds in the green mass of the sprouts and their length in comparison to a reference in water at pH = 7.0. In Research Institute of Horticulture, Skierniewice, Poland the usefulness of selected iopolymer preparations was evaluated as agents to protect decorative plants against some pathogens (on leaves, in soil) such as Phytophtora cryptogea causing decay of shoots and roots. It could be found that the biopolymer compositions applied to the soil provided a much better rooting of chrysanthemum cuttings in a Phytophtora cryptogea - infected soil. The cuttings were growing much faster and the number of infected ones was largely reduced. The usefulness of a number of chitosan formulations was also evaluated for seed pickling. It was found that the formulations exerted a distinctly positive impact upon the germination, growth and health of the seedlings. Laboratory and greenhouse testing was made in the Institute of Plant Protection, Poznań, Poland where the biological activity of some biopolymer compositions was evaluated. A first selection of the biopolymers was done based on an in vitro examination of the impact upon bacteria growth. (Gram negative - Erwinia amylovora and Gram positive Clavibacter ichiganensis ) on agar or agarose plates and upon the generation of necrotic stains on beans and tobacco caused by lucerne mosaic virus and tobacco mosaic virus respectively. It was found that the preparations with original biopolymer concentration had not affected the viruses directly but stimulated the plants’ immunity against the pathogens.
EN
The thermal decomposition of tin(II), lead(II), cadmium(II) and mercury(II) metal-alginate complexes has been studied using thermogravimetry (TG) and differential thermogravimetry (DTG) measurements. The TG curves showed three stages of weight loss, the DTG curves indicated the presence of a series of thermal stages associated with the TG curves. Dehydration of the coordinated water molecules occurred in the first stage, followed by decomposition of the dehydrated complexes in the next two stages. Thermal stability of these complexes in terms of the strength of chelation and coordination geometry is discussed.
6
Content available remote Kwas muraminowy znany i nieznany
63%
|
2008
|
tom Z. 72
105-118
PL
W pracy opisano stan wiedzy na temat specyficznej cząsteczki zwanej kwasem muraminowym, która występuje w polisacharydach ścian komórkowych bakterii i zarodników. W pracy omówiono jego strukturę, występowanie, właściwości fizykochemiczne, funkcje i przemiany, rolę biologiczna i fizjologiczną oraz metody analizy.
EN
The review describes present knowledge about the very specific molecule namely muramic acid which is an important constituent of bacteria cell walls. Details about physical and chemical characterization are presented with its physiological and biological roles, synthesis, bioconversion. Methods of analytical determination are also described.
|
2000
|
tom T. 54, nr 1
9-10
PL
Uzasadniono, że polisacharydy staną się surowcem XXI w. dla przemysłu chemicznego i branż parachemicznych (farmaceutycznej, kosmetycznej, spożywczej). Wskazano na rolę polisacharydów jako nośników energii, źródła podstawowych surow-ców przemysłowych (etanolu, metanolu) oraz biopolimerów poddających się licznym modyfikacjom fizycznym, chemicznym, fizykochemicznym i enzymatycznym. Opisano sposoby modyfikowania skrobi i zastosowań produktów modyfikacji. Za szerokim wykorzystaniem polisacharydów do celów spożywczych i niespożywczych przemawia ich odnawialność i biodegradowalność.
EN
Role of polysaccharides as 21st century resource for chemical. and parachemical industry (pharmaceutical. cosmetics. food) is presented. Polysaccharides should be considered as source of energy and basic chemicals (ethanol, methanol) as well as the material numerous physical, chemical, physicochemical, and enzymatic modifications. Several modifications are presented together with possibilities of their application in nutrition and for non-nutritive purposes. Versatility and biodegradability of polysaccharides justify.
EN
The rate of gel-growth for spherical ionotropic metal alginate gel droplets has been studied. Experimental observations have shown that the relaxation time of the metal alginate ionotropic gel complexes of the droplet shapes decreased in the order Hg > Cd > Sn > Pb-alginates, whereas the velocity of sinking under gravitational acceleration decreases in the same order. The factors which affect the relaxation time and velocity of acceleration, such as the concentration and viscosity of the alginate sol, the nature and radius of the metal ion as well as the density and pH of the electrolyte solution have been examined. The activation energies indicated that the stability of these metal alginate gel complexes follows the order Hg > Cd > Pb ~ Sn alginates. A mechanism consistent with the experimental results has been discussed.
PL
Artykuł stanowi przegląd literatury dotyczącej wykorzystania polimerów naturalnych (białek i polisacharydów) do wytwarzania jadalnych powłok powierzchniowych bądź opakowań artykułów żywnościowych. Omówiono wymagania stawiane takim materiałom oraz ich właściwości ze szczególnym uwzględnieniem przepuszczalności pary wodnej (WVP). Przedstawiono sposoby modyfikacji folii z polimerów naturalnych poprzez włączenie w ich struktury substancji hydrofobowych w celu poprawy ich właściwości barierowych w stosunku do pary wodnej.
EN
In the review the use of natural polymers (proteins, polysaccharides) for preparation of edible surface coatings or food packaging was presented. The requirements concerning such materials as well as their properties, especially water vapor permeability (WVP), were discussed. The methods of modification of natural polymer films by incorporation of hydrophobic substances into their structure to improve the barrier properties against water vapor, were presented.
PL
Artykuł jest kontynuacją przeglądu literatury dotyczącego jadalnych opakowań żywności wytwarzanych z polimerów naturalnych (białek lub polisacharydów, por. cz I. Polimery, 53, nr 9). Przedstawiono różne rodzaje modyfikacji na drodze sieciowania (fizycznego, chemicznego i enzymatycznego) folii opakowaniowych uzyskanych z takich materiałów. Sieciowanie jest konieczne w celu ograniczenia rozpuszczalności w wodzie i przepuszczalności pary wodnej (WVP) oraz polepszenia ich właściwości mechanicznych. Scharakteryzowano właściwości użytkowe omawianych folii w zależności od sposobu sieciowania. Opisano również efekty plastyfikacji folii za pomocą rozmaitych substancji plastyfikujących, stosowanej w celu wyeliminowania nadmiernej kruchości materiału i zwiększenia jego rozciągliwości.
EN
The article is a continuation of the review concerning edible food packaging made of natural polymers (proteins or polysaccharides, see Part 1. Polimery, 53, No. 9). Various methods of modification (physical, chemical or enzymatic cross-linking) of packaging films made of such materials were presented. Cross-linking is necessary to reduce solubility in water and water vapour permeability (WVP) of films or to improve their mechanical properties. Dependence of changes of the films' functional features on the crosslinking method was characterized. The results of plasticization of the film with various plasticizers, used to reduce the brittleness and to improve flexibility of the material were also described.
|
2000
|
tom T. 54, nr 4
16-18
PL
Omówiono liczne możliwości modyfikacji skrobi na sposób fizyczny, chemiczny, fizykochemiczny i enzymatyczny i zastosowania produktów modyfikacji. Za szerokim wykorzystaniem polisacharydów do celów spożywczych i niespożywczych przemawia ich odnawialność i biodegradowalność.
EN
Possibilities of numerous physical, chemical, physicochemical and enzymatic modifications are presented together with possibilities of applications for nutritive and non-nutritive purposes. Versatility and biodegradability of polysaccharides justify the concern.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.