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1.
A new thermal conductive poly(vinylidene fluoride) (PVDF) composite has been developed via a hybrid functionalized graphene sheets (FGS)-nanodiamonds (NDs) filler by a simple solution method. The PVDF composite showed different thermal conductivities at different proportion of hybrid filler. The thermal conductivity of the composite was up to 0.66 W/m·K for a mixture containing 45 wt% hybrid filler, which is about 2-fold increment in comparison to the PVDF martrix. The PVDF composites consisting of 20 wt% hybrid FGS/ND filler at the weight ratio of 1:3 shows the best thermal stability. The electrical conductivity of composites was increased from 5.1×10?15 S cm?1 (neat PVDF) to 7.1×10?7 S cm?1 of the PVDF composite with 10 wt% hybrid filler. 相似文献
2.
茶梗木质纤维素对儿茶素类吸附动力学研究 总被引：4，自引：1，他引：3
以茶梗为原料制备木质纤维素,通过静态吸附,研究茶梗木质纤维素在绿茶提取物溶液中对儿茶素类的吸附动力学。结果表明,茶梗木质纤维素对儿茶素类总量的吸附等温线符合Freundlich经验方程,随着温度的升高,茶梗木质素纤维素对儿茶素类的平衡吸附量降低;动力学研究数据用拟一级速率方程和拟二级速率方程模拟,其中拟二级速率方程拟合程度更高,在不同温度下利用拟二级速率方程计算的总儿茶素类饱和吸附量与实测值吻合。随着温度的升高,速率常数k1和k2提高,而总儿茶素类的初始吸附速率降低。 相似文献
3.
Spent grain, the major by-product of the brewing industry, was magnetically modified by contact with water-based magnetic fluid. The prepared material has been used as a new inexpensive magnetic adsorbent for the removal of water-soluble dyes. The dye adsorption could be described both with the Langmuir and Freundlich isotherms. The maximum adsorption capacities reached the value up to 72.4 mg of dye (Bismarck brown Y) per g of dried magnetically modified spent grain. 相似文献
4.
Melike Dizbay-Onat Evan Floyd Uday K. Vaidya Claudiu T. Lungu 《Fibers and Polymers》2018,19(4):805-811
Agricultural waste produced by the industry is a huge threat for the global environment. Utilization of agricultural waste is necessary and there is an urgent need to develop new techniques to solve this important problem. The main objective of this research was to evaluate the applicability of the activated carbon (AC) derived from industrial sisal fiber waste as passive samplers in monitoring toluene by comparing them to industry standard wafer and granular activated carbon (GAC). Carbonization time and ball milling effect on sisal fiber derived AC sample adsorption properties were investigated. Toluene adsorption isotherms were used to predict toluene adsorption capacities. Surface characteristics including surface area and pore volume were used to determine the relationships between them and adsorption capacity. Even though prepared AC samples have mesoporous structure, commercial samples have microporous structure. Surface area from 1245 m2/g to 1297 m2/g and toluene adsorption capacity from 21.4 % to 26.6 % was improved by increasing carbonization time from 1 h to 3 h at 650 °C carbonization temperature and 94.4 ml/min flow rate. Conversely, ball milling technique had negative effect by decreasing the surface area (674 m2/g) and the adsorption capacity of toluene (12.27 %). It is concluded that industrial sisal fiber waste have great potential as a precursor of AC for application in passive monitoring against toluene, particularly the produced mesoporous AC with 3 h carbonization time performs higher adsorption capacity (26.6 %) than commercially available microporous passive sampler (24.1 %) and GAC (22.8 %). 相似文献
5.
为探明西藏麦类作物中真菌毒素污染程度及产毒真菌种类与分布,以青稞、小麦为研究对象,对其籽粒中多种毒素进行分析,并对毒素污染阳性样品进行真菌分离鉴定。结果表明,2018年毒素总检出率为20.13%;杂色曲霉毒素检出率最高,为10.74%;OTA超标率最高,为3.36%;小麦的毒素检出率和超标率都高于青稞,二者的污染毒素种类以OTA、ZEN、ST为主。西藏高原42份被真菌毒素污染的农作物籽粒中共分离到199份真菌,分属23属67种真菌,青霉属为优势属,曲霉属次之。 相似文献
6.
抗虫水稻品种上饲养的白背飞虱种群的致害性变化 总被引：1，自引：0，他引：1
采用分别带有抗白背飞虱基因Wbph2和Wbph5的水稻品种ARC10239(ARC)和N'Diang(ND)作为选择寄主,获得第15代种群(ARC种群和ND种群),对这两个种群进行致害性检测.设RHT和TN1为抗感虫对照.结果表明这两个种群在其相应的寄主品种上分泌唾液和X波持续时间较短,而取食韧皮部的时间较长.ARC种群和ND种群分别在其相应的寄主品种和TN1上分泌的蜜露量没有显著差异,且明显大于其在RHT上分泌的蜜露量.在寄主品种和TN1上的产卵量明显高于RHT,发育卵率没有显著差异.ND种群在其寄主品种上的若虫存活率为45.0%,介于TN1(71.4%)和RHT(21.0%)之间,并与它们存在显著差异,ARC种群在其寄主品种上的若虫存活率为68.3%,与它在TN1上(77.5%)的若虫存活率之间没有显著差异,且明显高于RHT(22.6%).这两个种群若虫发育历期在其各自的选择寄主与TN1之间没有显著差异,且明显短于其在RHT上的发育历期.因此,这两个种群在取食和产卵方面已基本适应其相应的选择寄主品种,但ND种群的若虫存活率还较低. 相似文献
7.
ARC and ND colony were obtained by rearing the whitebacked planthopper (WBPH), Sogatella furcifera gene Wbph5) till 15 generations. Taichung Native 1 (TN1) and Rathu Heenati (RHT) served as susceptible and resistant check, respectively. The results of electronic recording revealed that duration of salivation and X-waveform of the two colonies on their corresponding hosts was short while the duration of phloem ingestion was long. The amount of honeydew excreted by ARC and ND colony did not differ on their corresponding host varieties from TN1 and was much higher than that of RHT. The number of eggs laid on their host varieties and TN1 were significantly higher than that on RHT. No distinct change was observed for these two colonies in term of percentage of developed eggs. The nymph survival rate of ND colony on its selection host was 45.0%, significantly different from that on TN1(71.4%) and RHT(21.0%), while that of ARC colony was 68. 3 %, not significantly different from that on TN1 (77.5 %), but much higher than that on RHT(22.6 %).The nymphal development duration of these two colonies on the corresponding hosts was not different from that on TN1, but significantly shorter than that on RHT. In brief, these two colonies had almost adapted to their corresponding host varieties based on feeding and oviposition, but the nymphal survival rate of ND colony was still low. 相似文献
8.
A major goal of biomimetics is the development of chemical compositions and structures that simulate the extracellular matrix. In this study, gelatin-based electrospun composite fibrous membranes were prepared by electrospinning to generate bone scaffold materials. The gelatin-based multicomponent composite fibers were fabricated using co-electrospinning, and the composite fibers of chitosan (CS), gelatin (Gel), hydroxyapatite (HA), and graphene oxide (GO) were successfully fabricated for multi-function characteristics of biomimetic scaffolds. The effect of component concentration on composite fiber morphology, antibacterial properties, and protein adsorption were investigated. Composite fibers exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli. The study observed that the composite fibers have higher adsorption capacities of bovine serum albumin (BSA) at pH 5.32–6.00 than at pH 3.90–4.50 or 7.35. The protein adsorption on the surface of the composite fiber increased as the initial BSA concentration increased. The surface of the composite reached adsorption equilibrium at 20 min. These results have specific applications for the development of bone scaffold materials, and broad implications in the field of tissue engineering. 相似文献
9.
SHENJun-hui WANGYan KazushigeSOGAWA MakotoHATTORI LIUGuang-jie 《水稻科学》2003,11(1):57-61
ARC and ND colony were obtained by rearing the whitebacked planthopper (WBPH), Sogatella furcifera(Horvath), exclusively on ARC10239 (ARC, carrying resistance gene Wbph2) and N‘Diang Marie (ND, carrying resistance gene WbphS) till 15 generations. Taichung Native 1 (TN1) and Rathu Heenati (RHT) served as susceptible and resistant check, respectively. The results of electronic recording revealed that duration of salivation and X-waveform of the two colonies on their corresponding hosts was short while the duration of phloem ingestion was long. The amount of honeydew excreted by ARC and ND colony did not differ on their corresponding host varieties from TN1 and was much higher than that of RHT. The number of eggs laid on their host varieties and TN1 were significantly higher than that on RHT. No distinct change was observed for these two colonies in term of percentage of developed eggs. The nymph survival rate of ND colony on its selection host was 45.0%, significantly different from that on TN1(71.4%0) and RHT(21.0%), while that of ARCcolony was 68. 3%, not significantly different from that on TN1(77.5%), but much higher than that on RHT(22.6%).The nymphal development duration of these two colonies on the corresponding hosts was not different from that on TN1, but significantly shorter than that on RHT. In brief, these two colonies had almost adapted to their corresponding host varieties based on feeding and oviposition, but the nymphal survival rate of ND colony was still low. 相似文献
10.
Andrea Castaneda Ricardo Ferraz Mnica Vieira Isabel Cardoso Vitor Vasconcelos Rosrio Martins 《Marine drugs》2021,19(6)
Neurodegenerative diseases (NDs) represent a drawback in society given the ageing population. Dementias are the most prevalent NDs, with Alzheimer’s disease (AD) representing around 70% of all cases. The current pharmaceuticals for AD are symptomatic and with no effects on the progression of the disease. Thus, research on molecules with therapeutic relevance has become a major focus for the scientific community. Cyanobacteria are a group of photosynthetic prokaryotes rich in biomolecules with confirmed activity in pathologies such as cancer, and with feasible potential in NDs such as AD. In this review, we aimed to compile the research works focused in the anti-AD potential of cyanobacteria, namely regarding the inhibition of the enzyme β-secretase (BACE1) as a fundamental enzyme in the generation of β-amyloid (Aβ), the inhibition of the enzyme acetylcholinesterase (AChE) lead to an increase in the availability of the neurotransmitter acetylcholine in the synaptic cleft and the antioxidant and anti-inflammatory effects, as phenomena associated with neurodegeneration mechanisms. 相似文献
11.
Yixi Wang Hao Wang Huili Peng Zhicun Wang Jianning Wu Zhiyong Liu 《Fibers and Polymers》2018,19(2):340-349
A novel eco-friendly porous adsorbent of cellulose (CE)/chitosan (CS) aerogel was prepared through sol-gel process and freeze-drying to remove Congo Red (CR). A series of aerogels were prepared by adjusting the mass ratios of CE and CS. Composite aerogels were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). SEM images showed that it was possible to change the structure of the aerogel by adjusting the amount of chitosan. The effects of dosage of chitosan, initial pH, temperature, adsorbent dosage, contact time, and initial dye concentration on adsorption capacities for CR were studied in detail. Batch adsorption studies showed that aerogel exhibited maximum removal efficiency to CR at a composite ratio of 1:3 and dosage of 2.5 g/l. CE/CS aerogel had excellent adsorption capacities for CR at a pH range of 3-11, which indicated stability of the aerogel in both acidic and alkaline conditions. CR adsorption on the composite aerogel fitted pseudo-second-order kinetics and Langmuir isotherm. The Langmuir isotherm model revealed that the maximum theoretical adsorption capacity of this material for CR was 381.7 mg/g at pH 7.0 at 303 K for 24 h. The adsorption mechanism included electrostatic and chemical interactions. The results indicated that the adsorption capacity of CE/CS aerogels was higher than the other chitosan composites adsorbents. 相似文献
12.
Guihua Meng Huili Peng Jianning Wu Yixi Wang Hao Wang Zhiyong Liu Xuhong Guo 《Fibers and Polymers》2017,18(4):706-712
Superhydrophobic cellulose and chitosan composite aerogel (SCECS) is fabricated through a novel and simple approach for the first time. During the preparation of cellulose and chitosan composite aerogel (CECS), chitosan is selfassemble into number micron-diameter particles on the surface of aerogel, which is similar to the micromorphology of a lotus leaf. Based on the rough surface, CECS is modified by sodium stearate through electrostatic interaction and ion exchange. Water contact angles of 156° are obtained for superhydrophobic aerogel. SCECS can remove various oils from water and with absorption capacities of 10 g/g for oil. Furthermore, the special structure of a non-porous of surface and porous layer of internal is benefit to separate surfactant-stabilized water-in-oil emulsions under gravity. 相似文献
13.
14.
Basalt fibers were surface modified by a new method using nanostructured porous silica aerogel via sol-gel process followed by ambient pressure drying method. FTIR, FE-SEM, and nitrogen adsorption analysis were used for characterization of silica aerogel particles which proved their mesoporous structure with pore size of 7 nm, high porosity and low density. FTIR spectra indicated the formation of silica aerogel on the basalt fibers surface. SEM analysis proved the surface modification of basalt fibers and quantitative measurement showed an increase of 2-fold in the surface roughness compared to unmodified surface fibers. A decrease of 42 % in the density of the surface modified basalt fibers was observed. Also, acoustical properties measurement showed that sound absorption coefficient was increased by 25 %. The obtained results show that silica aerogel structure can affect the physical properties of surface modified basalt fibers. Two silica aerogels with different density and porosity were used in this work. 相似文献
15.
Sabrine AlilaFadhel Aloulou Wim ThielemansSami Boufi 《Industrial Crops and Products》2011,33(2):350-357
Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 μmol g−1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles. 相似文献
16.
In this paper, the surface of magnetic manganese ferrite nanoparticles (MFN) was modified using cetyl trimethylammonium bromide (CTAB). The modified MFN was studied using Fourier transform infrared spectroscopy (FTIR). The adsorption capacity of surface modified MFN (MFN-CTAB) was investigated for dye removal for single and ternary systems. Three anionic dyes, C.I. Direct Red 80 (DR80), C.I. Direct Red 31 (DR31), and C.I. Acid Blue 92 (AB92), were used as model compounds. The effects of operational parameters on dye removal (i.e. adsorbent dosage, dye concentration and salt) and the kinetic and isotherm of dye adsorption were studied. The adsorption kinetic for the dyes was found to be well described by the pseudo-second order model. The maximum dye adsorption capacity (Q 0) of MFN-CTAB for DR80, DR31 and AB92 was 83 mg/g, 59 mg/g and 70 mg/g, respectively. The adsorption isotherm data were analyzed using the Langmuir, Freundlich, and Temkin equations. The results revealed that the Langmuir model fitted the adsorption data better. The results showed that the MFN-CTAB as a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions. 相似文献
17.
An ideal surface for implantable glucose sensors would be able to evade the events leading to chronic inflammation and fibrosis, thereby extending its utility in an in vivo environment. Nafion?, a perfluorinated ionomer, is the membrane material preferred for in situ glucose sensors. Unfortunately, the surface properties of Nafion? promote random protein adsorption and eventual foreign body encapsulation, thus leading to loss of glucose signal over time. Details of the techniques to render Nafion? nonprotein fouling are given in a previous article [T. I. Valdes et al., Biomaterials 29, 1356 (2008)]. Once random protein adsorption is prevented, a biologically active peptide can be covalently bonded to the treated Nafion? to induce cellular adhesion. Cellular responses to these novel decorated Nafion? surfaces are detailed here, including cell viability, cell spreading, and type I collagen synthesis. Normal human dermal fibroblasts (NHDFs) were cultured on control and modified Nafion? surfaces. Findings indicate that Nafion? modified with 10% 2-hydroxyethyl methacrylate and 90% tetraglyme created a nonfouling surface that was subsequently decorated with the YRGDS peptide. NHDFs were shown to have exhibited decreased type I collagen production in comparison to NHDF cells on unmodified Nafion? surfaces. Here, the authors report evidence that proves that optimizing conditions to prevent protein adsorption and enhance cellular adhesion may eliminate fibrous encapsulation of an implant. 相似文献
18.
Porous PLA fibrous membranes with different morphologies were successfully fabricated by varying the relative humidity. When the relative humidity was higher than 45 %, nanopores morphology appeared on the surface of PLA fibers. The micro-structures of PLA fibers and the packing densities and through-pore sizes of the PLA fibrous membranes were measured and found to greatly influence the smoke adsorption properties. The smoke adsorption was recorded in photos, and the process of how smoke adsorbed on the membranes was observed by SEM. The max removal efficiencies of nicotine, tar, water vapor, and carbon monoxide were 40.0 %, 36.9 %, 5.8 % and 13.6 % measured by a cigarette-smoking machine, and sensory evaluation was conducted to assess the practical application of fibrous membranes for smoke adsorption. 相似文献
19.
JA Snyder T Abramyan JA Yancey AA Thyparambil Y Wei SJ Stuart RA Latour 《Biointerphases》2012,7(1-4):56
Adsorption free energies for eight host-guest peptides (TGTG-X-GTGT, with X = N, D, G, K, F, T, W, and V) on two different silica surfaces [quartz (100) and silica glass] were calculated using umbrella sampling and replica exchange molecular dynamics and compared with experimental values determined by atomic force microscopy. Using the CHARMM force field, adsorption free energies were found to be overestimated (i.e., too strongly adsorbing) by about 5-9 kcal/mol compared to the experimental data for both types of silica surfaces. Peptide adsorption behavior for the silica glass surface was then adjusted using a modified version of the CHARMM program, which we call dual force-field CHARMM, which allows separate sets of nonbonded parameters (i.e., partial charge and Lennard-Jones parameters) to be used to represent intra-phase and inter-phase interactions within a given molecular system. Using this program, interfacial force field (IFF) parameters for the peptide-silica glass systems were corrected to obtain adsorption free energies within about 0.5 kcal/mol of their respective experimental values, while IFF tuning for the quartz (100) surface remains for future work. The tuned IFF parameter set for silica glass will subsequently be used for simulations of protein adsorption behavior on silica glass with greater confidence in the balance between relative adsorption affinities of amino acid residues and the aqueous solution for the silica glass surface. 相似文献
20.
Dr. Robert R. Selvendran 《Plant foods for human nutrition (Dordrecht, Netherlands)》1979,29(1-2):109-133
The binding of bile salts by dietary fibre plays an important role in cholesterol metabolism in man. In most of the adsorption studies of bile salts in vitro, the chemical composition of the fibre preparations has not been described, even broadly, nor has the effect of co-precipitated compounds (e.g. proteins) been considered. Hence, it seemed useful to investigate the adsorption of Na cholate (NaC) and Na taurocholate (NaTC) by well-defined cell wall material (CWM) from parenchymatous, lignified and cutinised tissues of mature runner bean pods as well as leeks under a variety of experimental conditions. This study was to identify the groups of polymers which are responsible for adsorption. The results showed dramatic differences in the adsorption characteristics of the wall preparations at different pH values. Some of the findings are reported below. The CWM from the various tissues was prepared by sequentially extracting the wet ball-milled tissues with 1% aq. Na deoxycholate and phenol/acetic acid/water (2:1:1, w/v/v). Experiments with labelled deoxycholate showed that the final preparations contained negligible amounts of adsorbed deoxycholate. Since the amount of residual starch in the preparations was small, no attempt was made to remove it; however, if required, this could be completely removed by extraction with 90% aq. dimethyl sulphoxide. The particle size of the preparations varied from 25–50 μm. For adsorption studies the following preparations were used: (1) whole-, depeetinated-and delignified-CWM from parenchymatous and lignified tissues of runner beans, together with the H and Na forms; (2) CWM of runner beans at different stages of maturity; (3) CWM of whole-and decutinised-leaves and cutinised tissues of leeks and (4) carboxymethyl cellulose and amberlite resin. The binding of bile salts was measured by a modified isotope-dilution procedure. The neutral sugars from the polysaccharides were determined as alditol acetates by GLC and an estimate of the uronic acid content of the preparations was obtained by a modified carbazole method. Experiments on the effect of pH on the binding of cholate by the various preparations showed that the adsorption capacity was very much dependent on the pH. The binding increased as the pH decreased. These experiments were complicated by the precipitation cholic acid at a pH value of <4. Nevertheless, an interaction between cholate and CWM persisted in acid solutions. Removal of pectic substances and lignin from the runner bean preparations resulted in a decrease of the adsorption capacity. The results suggested that the adsorption is greatest under conditions in which the ionization of cholic acid and the acidic groups of the cell wall polymers is at its lowest. Following these studies, determinations were made of the adsorption of cholate from an aqueous solution (without buffer) by wall preparations in the H and Na forms. With all the preparations the adsorption was greatest when these were in the H form. Adsorption studies with the preparations from leeks showed that the adsorption capacity of the parenchymatous tissues was considerably more than that of cutinised tissues. Hence, pectic substances in the H form (an not lignin or cutin) are probably the principal binding agents of cholate. The adsorption of Na taurocholate by the various preparations was independent of pH value. The implications of these results are discussed. 相似文献