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1.	Lundqvist, Jon, et al. (författare) Characterization of galactoglucomannan extracted from spruce (Picea abies) by heat-fractionation at different conditions 2003 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 51:2, s. 203-211 Tidskriftsartikel (refereegranskat)abstract Water-soluble hemicelluloses were extracted from spruce chips by microwave heat-fractionation. The galactoglucomannan (GGM) extraction was evaluated on the basis of weight-average molecular weight (MW), yield and carbohydrate composition of the GGM. The MW was determined by size-exclusion chromatography with column calibration using off-line MALDI-MS analysis, and determination of mannan content in the fractions collected. Water impregnated spruce chips were heat-fractionated at three different temperatures (180, 190, and 200oC). The spruce chips were also impregnated in NaOH solutions of different concentrations, and then heat-fractionated at 190oC for 5min. The highest mannan yield (78% based on the amount in the raw material) was obtained from water impregnated spruce chips heat-fractionated at 190oC for 5min (MW of 3800). The highest MW (14,000) was obtained from impregnation with 2% NaOH (190oC, 5min), but the yield of mannan was very low (3%). Impregnation with 0.025% NaOH and heat-fractionation at 190oC for 5min resulted in extraction of GGM with MW of 9500 and a mannan yield of 31%. When the spruce chips were impregnated with =<0.05% NaOH an O-acetyl-galactoglucomannan was extracted, whereas when higher NaOH charges were used in the impregnation, the extracted GGM lacked acetyl groups.
2.	Anthonsen, M.W., et al. (författare) Aggregates in acidic solutions of chitosans detected by static laser light scattering 1994 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 25:1, s. 13-23 Tidskriftsartikel (refereegranskat)abstract Chitosans having degrees of N-acetylation, FA, ranging from 0 to 0·6, were randomly degraded to different molecular weights and studied by multi angle static laser light scattering (LLS). Under the given experimental conditions, negative second virial coefficients of the solutions, A?2, revealed the presence of concentration dependent aggregates. Attempts to remove the aggregates, or to influence the aggregation behavior, were made by ultracentrifugation and extensive filtering of the solutions. Modification of the solvent conditions such as pH, ionic strength and temperature were carried out, and chitosan solutions were digested with an acidic proteinase. Non-degraded samples and chitosans prepared by both heterogeneous and homogeneous N-deacetylation of chitin were also studied. In all cases, the negative A?2 remained. However, it was observed that ultracentrifugation and filtering of the solutions decreased the measured molecular weights and radii of gyration, indicating that some of the material of high molecular weight and size could be removed by ultracentrifugation and filtration. The chemical nature of the physical basis of the molecular association was not revealed. Nevertheless, by the use of gel permeation chromatography coupled to an on-line low angle laser light scattering instrument and a differential refractive index concentration detector (HPSEC-LALLS-RI), a bimodal molecular weight distribution was observed in which about 5% of the sample had a very high molecular weight. These results coupled with the positive virial coefficients obtained earlier from osmotic pressure measurements suggest that a small fraction of the chitosan is aggregated to high molecular weight material, probably following a closed association model. Electron microscopy revealed the presence of some supramolecular structures. The positive second virial coefficients obtained earlier from osmometry are in harmony with these findings. The results demonstrate the occurrence of reversible aggregation in chitosan solutions. Static laser light scattering therefore cannot readily be used to determine molecular weights and sizes of chitosans under these conditions. It was not possible to correlate the extent of aggregation with the chemical composition of the chitosans. © 1994.
3.	Berggren, R., et al. (författare) Alkaline degradation of birch and spruce : influence of degradation conditions on molecular mass distributions and fibre strength 2003 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 51:3, s. 255-264 Tidskriftsartikel (refereegranskat)abstract The alkaline degradation of birch and Norway spruce during kraft pulping was studied on a laboratory scale by two degradation strategies, by varying the pulping time using the same initial alkali level and by varying the initial alkali concentration using a constant time. The degradation at the molecular level was monitored by determining the carbohydrate composition, intrinsic viscosity and-molecular mass distribution (MMD). The influence of the degradation on fibre strength was studied as zero-span tensile index. The alkaline degradation was to a large extent homogeneous on a molecular level. However, some significant differences in degradation patterns were found. In the case of birch, the two different degradation strategies (increased alkali level and increased pulping time) caused differences in MMD and fibre strength (comparisons made at a given intrinsic viscosity or M-w). For spruce pulps, the decrease in fibre strength and the shift in MMD were the same in both series, regardless of degradation strategy.
4.	Hermansson, Ann-Marie (författare) Rheological and microstructural evidence for transient states during gelation of kappa-carrageenan in the presence of potassium 1989 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 10:3, s. 163-181 Tidskriftsartikel (refereegranskat)abstract Kappa-carrageenan gelation was studied by a combination of electron microscopy and dynamic viscoelastic measurements. There was an initial maximum in the storage modulus during cooling and gel formation of 1% kappa-carrageenan in the presence of potassium. The structure of the transient state was found to consist of a fine network structure, where the junction zones were believed to be double helices. The structure had the characteristics of a true gel but was unstable. When the temperature was lowered aggregation took place and the fine network structure was partly broken down. Ordered superstrands formed which aligned themselves in parallel or were densely packed together. The degree of aggregation depended on the potassium ion concentration. In the weakest gel formed in 0·01 m KCl, the superstrands did not form a network but were rather dispersed in the fine network structure. In 0·1 and 0·2 m KCl the superstrands formed a three-dimensional network, where aligned superstrands formed the junction zones and branching occurred when superstrands deviated from each other and aligned with new superstrands. In 0·1 m KCl the supermolecular network dominated but in 0·2 m KCl a mixed gel was formed of the fine network and the coarse supermolecular network. The mixed gel gave rise to the firmest gel. © 1989.
5.	Hermansson, Ann-Marie (författare) Shear induced changes in the viscoelastic behaviour of heat treated potato starch dispersions 1990 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 13:1, s. 29-45 Tidskriftsartikel (refereegranskat)abstract The viscoelastic behaviour of native potato starch dispersions was studied using dynamic viscoelastic measurements. The influence of various shear and heat treatments of gelatinized starch pastes were compared in the concentration range 4-10%. Heating had a minor effect compared to the effect of shear treatment. The complex modulus (G) decreased to about 5% of its maximum value when the starch pastes were sheared during the heating cycle, whereas heating alone resulted in a decrease to about 60% of the maximum G value. Shear also caused an increase in the phase angle and characteristic changes were observed with regard to frequency and strain dependencies. When samples were prepared in a Brabender viscograph, the shear induced changes took place early in the pasting cycle. The characteristics of the concentration dependence differed due to the shear history of the sample. Peculiar concentration dependencies, some even negative, could be obtained from samples with different shear histories. The results imply that even moderate shear treatment gives rise to structure changes which are reflected by a transition in the type of the viscoelastic behaviour. © 1990.
6.	Lundin, Leif, et al. (författare) Influence of locust bean gum on the rheological behaviour and microstructure of K-?-carrageenan 1995 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 28:2, s. 91-99 Tidskriftsartikel (refereegranskat)abstract Mixtures of ?-carrageenan-locust bean gum (LBG) were analysed by transmission electron microscopy and dynamic viscoelastic measurements. The effect of two different mannose:galactose (M:G) ratios of LBG on the rheology and microstructure of ?-carrageenan in KCl was studied. The rheological differences observed in the mixed gel as LBGs were added were found to be dependent on M:G ratio, salt concentration and LBG content. Monolayers of dilute samples of ?-carrageenan mixed with LBGs in varying ratios in 0.10 M KCl were visualised by low-angle rotary metal shadowing for transmission electron microscopy. The results obtained showed that LBG hindered the self-association of ?-carrageenan, and that the effect was enhanced at a higher M:G ratio and as the LBG contents were increased. Small deformation viscoelastic measurements were performed on ?-carrageenan-LBG mixtures in 0.050 and 0.10 M KCl at constant temperatures of 38 and 48 °C, respectively. Increased rheological stability was observed for mixtures containing a relatively high LBG content. Mixtures with a relatively low LBG content showed a maximum in storage modulus and an increase in phase angle. The stabilising effect of LBG on the rheology of the blends was more effective for the LBG with high M:G and as the LBG content was increased. © 1996.
7.	Lundin, Leif, et al. (författare) Supermolecular aspects of xanthan - locust bean gum gels based on rheology and electron microscopy 1995 Ingår i: Carbohydrates polymer. - 0346-718X .- 0144-8617 .- 1879-1344. ; 26:2, s. 129-40 Tidskriftsartikel (refereegranskat)abstract The viscoelastic properties and supermolecular structure of synergistic gels, formed by xanthan and locust bean gum (LBG) of two different mannose:galactose ratios (M:G), have been investigated by small deformation viscoelastic measurements and by low angle rotary-shadowing for transmission electron microscopy. The rheological properties at 20°C for mixtures subjected to heating and cooling cycles in the temperature range 30-80°C were found to be dependent on the M:G ratio. Mixtures of xanthan and LBG mixed at temperatures ?40°C were found to form true gels with low phase angles. Blends of xanthan and LBG with a low M:G ratio did not show any increase in synergistic effects as the temperature was increased, whilst the mixture of xanthan and LBG with a high M:G ratio showed a strong increase in synergistic effects as the temperature was raised above 60°C. A difference in gelation temperature (Tg) of approx.13°C was observed between the mixtures of xanthan and the two LBG fractions. The Tg for xanthan with a high M:G ratio was approx. 53°C, whilst the Tg for mixtures of xanthan and LBG with a low M:G ratio was approx. 40°C. Results obtained using electron microscopy showed that the xanthan-LBG network was formed from xanthan supermolecular strands, and addition of LBG did not influence the xanthan structure. The observed structural features of the gels were independent of heat treatment and LBG fraction. The structural similarities and rheological differences observed between xanthan and the LBG fractions are discussed in comparison with existing interaction models at the molecular level. Based on these results, a speculative network model at the supermolecular level is presented.
8.	Stading, Mats, et al. (författare) Humidity-induced structural transitions in amylose and amylopectin films 2001 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 45:3, s. 209-217 Tidskriftsartikel (refereegranskat)abstract The effect of humidity on the dynamic mechanical and barrier properties and on the microstructure of amylose and amylopectin films was studied. The films were solution-gel-cast, with and without glycerol as added plasticizer, and dried to equilibrium weight under various relative humidities (RH). The network microstructure of glycerol-plasticized amylose films was shown to change from dense and homogeneous to a more open structure with fluctuations in the pore size when the surrounding RH was increased. The structural change was attributed to plasticization of the amorphous areas by increased water content, leading to higher mobility in the network and subsequent inhomogeneous swelling. This structural change had a direct influence on the oxygen permeability, which drastically increased. The onset of the increase occurred at lower surrounding RH for the films containing glycerol, and these films also had higher oxygen permeability. Glycerol-plasticized amylopectin films with gradually increased crystallinity were prepared by varying the RH during film formation. Dynamic mechanical analysis at both varied temperature and RH showed that the increased crystallinity led to higher glass transition temperature, T g, and a smaller effect of the surrounding humidity on mechanical and barrier properties. The RH during the formation of glycerol-plasticized amylose films did not affect crystallinity or T g. These films formed at 70% RH were shown to have a marked heterogeneous network. © 2001 Elsevier Science Ltd.
9.	Stading, Mats, et al. (författare) Rheological behaviour of mixed gels of kappa-carrageenan-locust bean gum 1993 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 22:1, s. 49-56 Tidskriftsartikel (refereegranskat)abstract Mixed gels of the K, Na and Ca-forms of ?-carrageenan and locust bean gum at a total polysaccharide concentration of 1% (w/w) were studied by dynamic viscoelastic measurements. Synergistic effects were only observed for mixed gels with K-?-carrageenan in ?0·1 m KCl. The composition favouring maximum synergy shifted from 90%-?-carrageenan in distilled water down to 35% K-?-carrageenan in 0·1 m KCl. Gels of K-?-carrageenan/locust bean gum did not show synergistic effects at high potassium concentration (0·2 m KCl). The typical behaviour of K-?-carrageenan at ?50 mm KCl dominated the rheological behaviour of the mixed systems even when the locust bean gum content was high. The synergistic effects probably originate from different mechanisms at low, 0-10 mm KCl, and high, 50-100 mm KCl, concentrations because of differences in the potassium-induced microstructure. The mixed gels with the Na or Ca-form of ?-carrageenan showed no synergy. Addition of locust bean gum caused the storage modulus to decrease and the phase angle to increase. The gels were weak, with G? < 170 Pa for the Na form and G? < 350 Pa for the Ca form. The mixed gels with both the Na and Ca forms had a broken frequency dependence of G?(f). © 1993.
10.	Svegmark, Karin, et al. (författare) Changes induced by shear and gel formation in the viscoelastic behaviour of potato, wheat and maize starch dispersions 1991 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 15:2, s. 151-169 Tidskriftsartikel (refereegranskat)abstract The effect of shear and gel formation on the behaviour of heat-treated wheat, maize and potato starch dispersions was studied using dynamic viscoelastic measurements. The starch types were compared both at a concentration of 10% and at concentrations where the same level of shear forces was applied during the paste preparation procedure (11% wheat, 10% maize, and 4% potato). The cereal and the potato starch pastes initially showed similar viscoelastic properties after gelatinization, but the cereal starch pastes underwent a transition in their viscoelastic behaviour when cooled. This transition was believed to be due to the gelation of amylose. The main changes observed were a sharp increase in the shear modulus and a drop in the phase angle to below 2 degrees. No such transition occurred on cooling the potato starch pastes, at 25°C for 1 h, in the concentration range studied (4-10%).
11.	Svegmark, K., et al. (författare) Molecular structures obtained from mixed amylose and potato starch dispersions and their rheological behaviour 1993 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 22:1, s. 19-29 Tidskriftsartikel (refereegranskat)abstract Transmission electron microscopy (TEM) and dynamic viscoelastic measurements were used to study the effects of varying the ratio of potato starch to amylose. Solubilised amylose was mixed with two different types of potato starch: one with starch in the form of swollen granules and the other in the form of a molecular dispersion. The total concentration was kept constant at 8% (w/w). When the level of added amylose was low, the shear modulus (G) was higher for gels with swollen granules than for molecular dispersions of starch. When the level of added amylose was high, the value of G was approximately the same, independent of the type of starch structure. The rheological data were evaluated by a model treating the added amylose and potato starch as phase-separated systems. The model showed that the inherent amylose of potato starch did not contribute markedly to the gel strength caused by the added amylose. Potato starch alone does not form strong gels in the time scale studied. TEM studies confirmed that the inherent and the added amylose gave rise to completely different types of structure. The added amylose had an open network structure of stiff strands. This type of structure was found in the mixed systems with added amylose and starch, but not in systems with only potato starch. Solubilised amylopectin appeared to have a droplet-like structure, often found in the form of a string of beads. © 1993.
12.	Abdelhamid, Hani Nasser, et al. (författare) In-situ growth of zeolitic imidazolate frameworks into a cellulosic filter paper for the reduction of 4-nitrophenol 2021 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 274 Tidskriftsartikel (refereegranskat)abstract Whatman (R) cellulosic filter paper was used as a substrate for the synthesis of two zeolitic imidazolate frameworks (ZIFs); ZIF-8 and ZIF-67 with and without 2,2,6,6-tetramethyl-1-piperidine oxoammonium salt (TEMPO) oxidized cellulose nanofibril (TOCNF). All synthesis procedures take place at room temperature via a one-pot procedure. The synthesis steps were followed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transforms infrared (FT-IR). Data indicated the formation of metal oxide that converted to a pure phase of ZIFs after the addition of the organic linker i.e. 2-methyl imidazole (Hmim). The materials were characterized using XRD, FT-IR, SEM, energy dispersive X-ray (EDX), nitrogen adsorption-desorption isotherms, and X-ray photoelectron microscope (XPS). Data analysis confirms the synthesis of ZIFs into Whatman (R) filter paper. The materials were used for the reduction of pollutants such as 4-nitrophenol (4-NP) compound to 4-aminophenol (4-AP). The materials exhibit high potential for water treatment and may open new exploration for hybrid materials consisting of cellulose and ZIFs.
13.	Abitbol, Tiffany, et al. (författare) Cellulose nanocrystal/low methoxyl pectin gels produced by internal ionotropic gelation. 2021 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 260 Tidskriftsartikel (refereegranskat)abstract The biotechnological applications of cellulose nanocrystals (CNCs) continue to grow due to their sustainable nature, impressive mechanical, rheological, and emulsifying properties, upscaled production capacity, and compatibility with other materials, such as protein and polysaccharides. In this study, hydrogels from CNCs and pectin, a plant cell wall polysaccharide broadly used in food and pharma, were produced by calcium ion-mediated internal ionotropic gelation (IG). In the absence of pectin, a minimum of 4 wt% CNC was needed to produce self-supporting gels by internal IG, whereas the addition of pectin at 0.5 wt% enabled hydrogel formation at CNC contents as low as 0.5 wt%. Experimental data indicate that CNCs and pectin interact to give robust and self-supporting hydrogels at solid contents below 2.5 %. Potential applications of these gels could be as carriers for controlled release, scaffolds for cell growth, or wherever else distinct and porous network morphologies are required.
14.	Albornoz-Palma, Gregory, et al. (författare) Relationship between rheological and morphological characteristics of cellulose nanofibrils in dilute dispersions 2019 Ingår i: Carbohydrate Polymers. - : Elsevier Ltd. - 0144-8617 .- 1879-1344. Tidskriftsartikel (refereegranskat)abstract The morphology of cellulose nanofibrils (CNFs), the rheological characteristics of their dispersions, and the corresponding relationships, are fundamental for understanding the properties of the material. This work aims at understanding how the morphological characteristics of the CNFs affect the rheology of the dispersions in the dilute region and to establish a relationship between both properties. A strong relationship was observed between the intrinsic viscosity of the CNF dispersions and their aspect ratio, which can be correlated through the expression ρ[η]=0.051p1.85. When comparing the model obtained in this work to the wormlike chain model, it was possible to verify that these models are independent of the flexibility of the CNFs. Regarding the fibrillation process, the dynamic viscosity only reflects part of the behavior of the morphological properties of the CNFs and does not provide reliable data that would allow these characteristics to be inferred, while the intrinsic viscosity does allow this relationship.
15.	Altskär, Annika, et al. (författare) Some effects of processing on the molecular structure and morphology of thermoplastic starch 2008 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 71:4, s. 591-597 Tidskriftsartikel (refereegranskat)abstract Hydroxypropylated and oxidised potato starch (HONPS) was used together with glycerol and water to produce thermoplastic starch. The amount of glycerol was kept constant at 22 parts by weight per 100 parts of dry starch. The thermoplastic starch was converted into films/sheets using three different processing techniques; casting, compression moulding and film blowing. The last two methods represent typical thermoplastic conversion techniques requiring elevated processing temperatures. By means of size-exclusion chromatography, it was found that compression moulding and film blowing led to some degradation of high-molecular weight amylopectin as well as of high-molecular weight amylose-like molecules. The degradation was significantly less pronounced for the cast films. The morphology of the specimens was quite complex and phase separations on different levels were identified. In the cast films and, to a lesser extent, in the compression-moulded specimens, a fine network structure could be distinguished. Such a structure could however not be ascertained in the film-blown material and this is discussed in terms of the thermo-mechanical treatment of the starch materials. © 2007 Elsevier Ltd. All rights reserved.
16.	Alves, Luis, et al. (författare) Dissolution state of cellulose in aqueous systems. 2. Acidic solvents 2016 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 151, s. 707-715 Tidskriftsartikel (refereegranskat)abstract Cellulose is insoluble in water but can be dissolved in strong acidic or alkaline conditions. How well dissolved cellulose is in solution and how it organizes are key questions often neglected in literature. The typical low pH required for dissolving cellulose in acidic solvents limits the use of typical characterization techniques. In this respect, Polarization Transfer Solid State NMR (PT ssNMR) emerges as a reliable alternative. In this work, combining PT ssNMR, microscopic techniques and X-ray diffraction, a set of different acidic systems (phosphoric acid/water, sulfuric acid/glycerol and zinc chloride/water) is investigated. The studied solvent systems are capable to efficiently dissolve cellulose, although degradation occurs to some extent. PT ssNMR is capable to identify the liquid and solid fractions of cellulose, the degradation products and it is also sensitive to gelation. The materials regenerated from the acidic dopes were found to be highly sensitive to the solvent system and to the presence of amphiphilic additives in solution.
17.	Alves, Luis, et al. (författare) Revisiting the dissolution of cellulose in H3PO4(aq) through cryo-TEM, PTssNMR and DWS 2021 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 252 Tidskriftsartikel (refereegranskat)abstract Cellulose can be dissolved in concentrated acidic aqueous solvents forming extremely viscous solutions, and, in some cases, liquid crystalline phases. In this work, the concentrated phosphoric acid aqueous solvent is revisited implementing a set of advanced techniques, such as cryo-transmission electronic microscopy (cryo-TEM), polarization transfer solid-state nuclear magnetic resonance (PTssNMR), and diffusing wave spectroscopy (DWS). Cryo-TEM images confirm that this solvent system is capable to efficiently dissolve cellulose. No cellulose particles, fibrils, or aggregates are visible. Conversely, PTssNMR revealed a dominant CP signal at 25 °C, characteristic of C-H bond reorientation with correlation time longer than 100 ns and/or order parameter above 0.5, which was ascribed to a transient gel-like network or an anisotropic liquid crystalline phase. Increasing the temperature leads to a gradual transition from CP to INEPT-dominant signal and a loss of birefringence in optical microscopy, suggesting an anisotropic-to-isotropic phase transition. Finally, an excellent agreement between optical microrheology and conventional mechanical rheometry was also obtained.
18.	Amaral, Sarah da Costa, et al. (författare) Cytotoxic effect of crude and purified pectins from Campomanesia xanthocarpa Berg on human glioblastoma cells 2019 Ingår i: Carbohydrate Polymers. - : ELSEVIER SCI LTD. - 0144-8617 .- 1879-1344. ; 224 Tidskriftsartikel (refereegranskat)abstract A new source of pectin with a cytotoxic effect on glioblastoma cells is presented. A homogeneous GWP-FP-S fraction (M-w, of 29,170 g mol(-1)) was obtained by fractionating the crude pectin extract (GW) from Campomanesia xanthocarpa pulp. According to the monosaccharide composition, the GWP-FP-S was composed of galacturonic acid (58.8%), arabinose (28.5%), galactose (11.3%) and rhamnose (1.1%), comprising 57.7% of homogalacturonans (HG) and 42.0% of type I rhamnogalacturonans (RG-I). These structures were characterized by chromatographic and spectroscopic methods; GW and GWP-FP-S fractions were evaluated by MIT and crystal violet assays for their cytotoxic effects. Both fractions induced cytotoxicity (15.55-37.65%) with concomitant increase in the cellular ROS levels in human glioblastoma cells at 25-400 mu g mL(-)(1), after 48 h of treatment, whereas no cytotoxicity was observed for normal NIH 3T3 cells. This is the first report of in vitro bioactivity and the first investigation of the antitumor potential of gabiroba pectins.
19.	Amoli, MS, et al. (författare) The development of a 3D printable chitosan-based copolymer with tunable properties for dentoalveolar regeneration 2022 Ingår i: Carbohydrate polymers. - : Elsevier BV. - 1879-1344 .- 0144-8617. ; 289, s. 119441- Tidskriftsartikel (refereegranskat)
20.	Andrade Pires, Amanda do Rocio, et al. (författare) Cytotoxic effect of a mannogalactoglucan extracted from Agaricus bisporus on HepG2 cells 2017 Ingår i: Carbohydrate Polymers. - : ELSEVIER SCI LTD. - 0144-8617 .- 1879-1344. ; 170, s. 33-42 Tidskriftsartikel (refereegranskat)abstract A mannogalactoglucan (RK2-Ab; M-w, 1.8 x 10(4) g mol(-1)) composed by Man (27.3%), Gal (24.4%) and Glc (48.3%) was extracted and characterized from Agaricus bisporus, and its biological activity was evaluated on human hepatocarcinoma cells (HepG2). The partially-O-methylated alditol acetates together with the NMR data suggest the main chain to be composed of alpha-D-Galp (32.8%) and beta-D-Glcp (37.0%) units (1 -> 6) -linked, with beta-D-Manp (14.6%), as non-reducing end units, substituting the side chains at O-2 (alpha-D-Galp units; 3.3%) and O-2 and O-4 (beta-D-Glcp units; 3.6%). (1 -> 2) -linked beta-D-Glcp (2.7%) and beta-D-Manp (6.0%) can also be observed. RK2-Ab reduced cellular viability of HepG2 cells, by both, the MTT and lactate dehydrogenase release assays, promoted the increase of cytochrome c release and decrease of ATP content. Suggesting that the mannogalactoglucan from A. bisporus may have antitumor activity by inducing apoptosis by the mitochondria death pathway, and could be used in cancer therapy.
21.	Anugwom, I, et al. (författare) Selective Extraction of Hemicelluloses from Spruce using Switchable Ionic Liquids 2012 Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 87:3, s. 2005-2011 Tidskriftsartikel (refereegranskat)abstract Switchable Ionic Liquids (SILs) made from alcohols, either hexanol or butanol, and CO2 together with an amidine (1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)) were investigated as dissolution/fractionation solvents for wood material. Both native spruce (Picea abies), and pre-extracted spruce were treated with either butanol SIL (SIL1) or hexanol SIL (SIL 2) for 5 days at 55 °C under normal pressure. The SILs were formed by bubbling CO2 through an equimolar mixture of either 1-hexanol or 1-butanol and DBU. The viscosity of the mixture increased from 7.1 mPas to 2980 mPas for SIL 2 and 5.1 to 1600 mPas for SIL 1. Melting points of the SILs 1 and 2 were at 8 and 14 °C, respectively. After the treatment time (5 days), the undissolved fraction contained 38 wt % less hemicelluloses compared to native spruce. There was an increase in the glucose content of the milled spruce treated with both SILs, since the milling step reduced the cellulose crystallinity of the wood and facilitated an easier SIL access into the wood. The solvents were very neutral in terms of lignin removal. Consequently, only about 2% of the lignin was removed from native wood. Moreover, a priori removal of the wood extractives did not influence the lignin removal. Highlights► Switchable Ionic Liquids made from, either hexanol or butanol, and CO2 together with an amidine (DBU) were studies as dissolution/fractionation solvents for spruce wood. ► After the treatment undissolved fraction contained 38 wt-% less hemicelluloses. ► We conclude that Switchable ionic liquids are effective solvent for fractionation of wood material, and they are easily recycled and can be reused.
22.	Atoufi, Zhaleh, et al. (författare) Surface tailoring of cellulose aerogel-like structures with ultrathin coatings using molecular layer-by-layer assembly 2022 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 282 Tidskriftsartikel (refereegranskat)abstract Cellulose nanofibril-based aerogels have promising applicability in various fields; however, developing an effi-cient technique to functionalize and tune their surface properties is challenging. In this study, physically and covalently crosslinked cellulose nanofibril-based aerogel-like structures were prepared and modified by a mo-lecular layer-by-layer (m-LBL) deposition method. Following three m-LBL depositions, an ultrathin polyamide layer was formed throughout the aerogel and its structure and chemical composition was studied in detail. Analysis of model cellulose surfaces showed that the thickness of the deposited layer after three m-LBLs was approximately 1 nm. Although the deposited layer was extremely thin, it led to a 2.6-fold increase in the wet specific modulus, improved the acid-base resistance, and changed the aerogels from hydrophilic to hydrophobic making them suitable materials for oil absorption with the absorption capacity of 16-36 g/g. Thus, demon-strating m-LBL assembly is a powerful technique for tailoring surface properties and functionality of cellulose substrates.
23.	Azhar, Shoaib, 1980-, et al. (författare) Extraction of hemicelluloses from fiberized spruce wood 2015 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 117, s. 19-24 Tidskriftsartikel (refereegranskat)abstract A novel mechanical pre-treatment method was used to separate the wood chips into fiber bundles in order to extract high molecular weight wood polymers. The mechanical pre-treatment involved chip compression in a conical plug-screw followed by defibration in a fiberizer. The fiberized wood was treated with hot water at various combinations of time and temperature in order to analyze the extraction yield of hemicelluloses at different conditions. Nearly 6 mg/g wood of galactoglucomannan was obtained at 90◦C/120min which was about three times more than what could be extracted from wood chips. The extracted carbohydrates had molecular weight ranging up to 60 kDa. About 10% of each of the extracted material had a molecular weight above 30 kDa. The extraction liquor could also be reused for consecutive extractions with successive increase in the extraction yield of hemicelluloses.
24.	Bai, Yunfei, et al. (författare) Sustainable cellulose foams for all-weather high-performance radiative cooling and building insulation 2024 Ingår i: Carbohydrate Polymers. - 0144-8617 .- 1879-1344. ; 333, s. 121951- Tidskriftsartikel (refereegranskat)abstract Passive daytime radiative cooling (PDRC) as a zero-energy-consumption cooling technique offers rich opportunities in reducing global energy consumption and mitigating CO2 emissions. Developing high-performance PDRC coolers with practical applicability based on sustainable materials is of great significance, but remains a big challenge. Herein, polyvinyl alcohol (PVA) and esterified cellulose (EC) extracted from sawdust were used as raw materials to construct foams by using a dual-crosslinking assisted-unidirectional freeze-drying strategy followed by hydrophobic surface modification. The resultant PVA/EC (PEC) foams with ideal hierarchical macropore structure displayed various excellent features, such as low thermal conductivity (26.2 mW·m−1·K−1), high solar reflectance (95 %) and infrared emissivity (0.97), superhydrophobicity as well as high mechanical properties. The features allowed the PEC foams to be used as radiative coolers with excellent PDRC performance and thermal insulating materials. A maximum sub-ambient temperature drops of 10.2 °C could be achieved for optimal PEC foams. Building simulations indicated that PEC foams could save 55.8 % of the energy consumption for Xi'an. Our work would give inspiration for designing various types of PDRC coolers, including but certainly not limited to foams-based radiative coolers.
25.	Barbieri, Shayla Fernanda, et al. (författare) Extraction, purification and structural characterization of a galactoglucomannan from the gabiroba fruit (Campomanesia xanthocarpa Berg), Myrtaceae family 2017 Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 174, s. 887-895 Tidskriftsartikel (refereegranskat)abstract In this study, we isolated and structurally characterized, for the first time, a galactoglucomannan (GGM) from the pulp of gabiroba, a Myrtaceae family species. The HPSEC-MALLS-RI analysis showed a homogeneous polysaccharide with molar mass of 25,340 g mol(-1). The monosaccharide composition showed that the GGM consisted of Man:Glc:Gal in a molar ratio of 1:1:0.6. Methylation and 1D and 2D NMR analyses suggested that the main chain of the GGM consisted of beta-D-Glcp and beta-D-Manp units (1 -> 4)-linked. The alpha-D-Galp substitutions occur mainly at O-6 position of beta-D-Manp units. The glycosidic linkages of the GGM were evident by the presence of the characteristic signals of 4-O-substituted residues at delta 78.6/3.69 for both beta-D-Glcp and beta-D-Manp. Furthermore, the 0-6 substitutions for both beta-D-Glcp and beta-D-Manp units were confirmed by signals at delta 67.1/4.00 and 3.93. The interglycosidic correlations, obtained through the analysis of the HMBC spectrum, further confirm the structure. (C) 2017 Elsevier Ltd. All rights reserved.

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