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1.
离子交联壳聚糖/海藻酸钠可降解复合膜的研究 总被引：1，自引：0，他引：1
以壳聚糖和海藻酸钠为原料、10%柠檬酸钠和3%氯化钙溶液为交联剂,制备1种可降解复合膜,研究交联时间和交联pH对复合膜机械性质和抗水性的影响,并通过X-射线衍射(XRD)和差示扫描量热法(DSC)对其结构和热稳定性进行分析。结果发现,复合膜的厚度(24.2μm)小于壳聚糖膜和海藻酸钠膜厚度相加的总和(39μm),表明在复合膜的制备过程中,壳聚糖与海藻酸钠在界面处部分混合并可能存在相互作用;柠檬酸钠和氯化钙分别对壳聚糖和海藻酸钠产生离子交联作用,且交联降低了二者的结晶度,提高了复合膜的热稳定性;在交联溶液pH为7、交联时间30min时,复合膜性质最好,机械强度最高可达到120MPa,水溶性仅为8.25%;复合膜改善了单一膜机械性能不足及抗水性差等缺点,有望应用于食品的保鲜包装。 相似文献
2.
应用海藻酸钠作为表面活性层材料,以戊二醛为交联剂,以聚砜超滤膜为支撑层,制备了1种新型荷负电纳滤膜。研究了复合纳滤膜的制备影响因素及操作条件对膜性能的影响,结果表明当海藻酸钠的浓度为2.0%,戊二醛溶液的浓度为0.9%,30℃下交联4 h条件下制备的复合膜的膜性能(截留率)最好。实验结果表明:对1 000 mg.L-1的Na2SO4,MgSO4,NaCl和MgCl2盐溶液的截留率分别为87.2%,21.5%,32.0%,12.2%,通量依次为30.6,35.2,33.5,22.4 L.h-1.m-2。 相似文献
3.
一种新型生物交联剂的制备及其性质 总被引：2，自引：0，他引：2
为在海藻酸钠分子中引入新的活性功能基团,制备出1种新型生物交联剂.本研究采用高碘酸钠氧化法,得到含不同醛基量的氧化海藻酸钠,用MTT法评价了它们的细胞毒性,并对其体内降解性和生物相容性进行了研究.结果表明:氧化海藻酸钠(氧化度<50%)的细胞毒性为0～2级,氧化度越高其细胞毒性越强;含相同醛基量的氧化海藻酸钠(氧化度为24%)与戊二醛相比,前者对细胞无明显抑制作用,毒性较低,而后者明显抑制细胞的生长,具有很强的细胞毒性.体内降解性和生物相容性实验结果表明,适度氧化的海藻酸钠不但保留了海藻酸钠良好的生物相容性,而且改善了其降解性.所以,适度氧化的海藻酸钠是1种新型的低毒性生物交联剂. 相似文献
4.
利用湿法纺丝技术制备了琼胶/SiO2复合纤维，对琼胶分子在溶液中的分散性、纺丝液流变性、纤维的形貌、化学结构分别用DLS、旋转黏度计、SEM、FTIR和XRD进行了表征，并对纤维的力学性能、热性能和吸湿性能进行了测定。研究结果表明：琼胶分子在溶液中呈纳米尺度分布，纺丝液具有良好的流动性；琼胶/纳米SiO2复合纤维具有良好的形态。随着纳米SiO2的添加量逐渐提高，复合纤维的力学拉伸强度先增强后降低，复合纤维的吸水性降低，复合纤维的热稳定性逐渐增强。结合复合纤维综合性能，纳米SiO2的最佳添加质量分数为0.5%。 相似文献
5.
诱导三倍体太平洋牡蛎群体发育过程中三倍体率的变化 总被引：1，自引：0，他引：1
借助染色体计数和流式细胞计数计对 6 - DMAP处理和冷休克两种诱导方法获得太平洋牡蛎 (Crassostrea gigas)三倍体群体在各个发育时期三倍体率进行了系统检测。结果发现 ,在 4～ 8细胞时期 ,6 - DMAP诱导三倍体率为 75 % ,冷休克诱导三倍体率为 5 0 % ,在发育至 D形幼虫期和稚贝期 ,两类三倍体群体的三倍体率均有所下降。如从 4～ 8细胞期发育至稚贝期 ,冷休克诱导群体下降了 5 3.0 8%以上 ,6 - DMAP诱导群体三倍体率下降了 2 7.36 %。养殖一年后 ,6 - DMAP诱导群体三倍体率仍保持在 6 0 %以上 ,而冷休克诱导群体三倍体率已下降至不足 10 %。这一结果说明 ,利用 6 - DMAP诱导来获得三倍体是比较理想的方法 相似文献
6.
中国江蓠属红藻所含琼胶的结构特征 总被引：4，自引：1，他引：4
用分级法和(13)~C-NMR研究了从中国产江蓠属红藻(真江蓠、细基江蓠、芋根江蓠和凤尾菜)提取的6份琼胶多糖的结构特征。这些琼胶主要由用0.5mol/L和1.0mol/LNaCl从DEAE-Sephadex A 50层析柱洗脱下的带电荷的琼胶糖分子组成。6.0mol/L尿素级分是带低电荷密度的琼胶糖分子。各级分总得率达80％或以上。(13)~C-NMR谱图表明各种江蓠琼胶的主要级分基本上由琼胶糖结构构成,但有的级分中琼胶糖含微量6-SO_4-L-半乳糖,真江蓠和细基江蓠的琼胶糖含有6-OCH_3-D-半乳糖,而凤尾菜琼胶中则主要含有2-OCH_3-3,6-内醚-L-半乳糖。真江蓠和凤尾菜的个别级分的琼胶酶降解产物与(13)~C-NMR分析结果相一致。 相似文献
7.
可食性壳聚糖包装膜的制备及其性质研究 总被引：7，自引：0，他引：7
以壳聚糖为成膜剂 ,以体积比为 1 %的乙酸水溶液为溶剂配制成壳聚糖成膜液 ,在成膜液中加入硬脂酸 ,用流涎法分别制成壳聚糖简单可食性包装膜和壳聚糖硬脂酸复合可食性包装膜。对膜的性能如抗拉强度、伸长率、水蒸气透过率、气体透过率、折痕等进行了分析。结果表明 ,膜性能的优劣与壳聚糖、硬脂酸等含量及成膜时的条件有关。 相似文献
8.
江蓠琼胶产率、物理性质和化学组成的季节变化 总被引：4，自引：0，他引：4
六十年代以前,我国主要用石花菜作琼胶原料,为弥补石花菜资源的不足,我们开展了用江蓠制造琼胶的研究,并取得了成功,使江蓠也成了制造琼胶的良好原料。但是,由于江蓠的种类、生长环境和采集季节等的不同,所含琼胶的数量及其物理化学性质变化很大,有的产琼胶率高、质量好,有的则很差。1946年美国的DeLoach分析了江蓠(G.verrucosa)的琼胶产率和凝胶强度的季节变化。其后,John等人研究了加纳齿江蓠(G.dentata)。Hoyle研究了夏威夷的脆江蓠(G.bursapastoris)和伞房江蓠(G.coronpifolia)的琼胶产率和凝胶强度的季节变化。Oza除测定了印度的皮江蓠(G.corticata) 相似文献
9.
对重组表达的海洋生物抗菌肽对虾素3-2进行亲和层析纯化,以海藻酸钠为壁材,采用凝聚法制备了重组抗菌肽海藻酸钠微囊,以微囊的形态和包封率为指标优化制备工艺,对制备的微囊进行体外释放特征的初步研究。结果显示,在氯化钙浓度为1.5%,海藻酸钠浓度为2.0%时,制备的微囊为完整的球形,冷冻干燥后的直径约为1.1 mm,包封率为83.87%。微囊在模拟胃液(pH 2.0)中2 h左右释放量趋于稳定,释放量低于14%;微囊在模拟肠液(pH 7.8)中不断释放,5 h时释放量达98%,表明微囊具有良好的肠溶性而可以抵抗胃液的破坏,可以用作重组抗菌肽缓释/控释制剂,为抗菌肽在水产病害防治过程的口服给药提供实验基础。 相似文献
10.
海洋脂肪酶ADM47601固定化方法的研究 总被引：1，自引：1，他引：0
采用海藻酸钠、壳聚糖、聚乙烯醇和明胶等材料, 进行对脂肪酶ADM47601的固定化研究。结果表明, 使用壳聚糖固定化脂肪酶, 在最优条件为2% (W/V)壳聚糖, 10% NaOH, 1%乙酸, 0.25%戊二醛, 每克载体添加840U脂肪酶时, 最大固定化酶活力回收率为87.06%。使用海藻酸钠-明胶固定化脂肪, 在最优固定化条件下, 最大固定化酶活力回收率为54.45%。使用聚乙烯醇固定化脂肪酶, 在最优固定化条件下, 最大固定化酶活力回收率为33.22%。使用海藻酸钠固定化脂肪酶, 在最优固定化条件下, 最大固定化酶活力回收率为17.11%。对比四种不同固定化酶方法, 脂肪酶活力回收率高度高低顺序为: 壳聚糖吸附交联法>海藻酸钠明胶协同包埋法>聚乙烯醇-硼酸法>海藻酸钠包埋法。 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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15.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
16.
The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
17.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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19.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
20.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献