First aid for flood-damaged paper using saltwater: The inhibiting effect of saltwater on mold growth

Abstract

With the aim of developing a new easy-to-use method for rescuing flood-damaged paper, the effect of saltwater on the inhibition of fungal growth on paper was investigated. This procedure could be used instead of, or assisted by freeze drying. Cellulose-digesting Trichoderma reesei, three types of fungi representative of fungi growing on paper (T. reesei, Aspergillus terreus, and Aureobasidium pullulans) and various naturally airborne fungi were cultured on cellulosic materials in liquid media containing artificial seawater with different salt concentrations. The addition of salts successfully inhibited the growth of T. reesei on microcrystalline cellulose at the concentration of 3.2% (m/m) or higher. The critical salt concentration, 3.2%, is within the general range of salt content in seawater. Other solutions of salts similar to sodium chloride also inhibited fungal growth. Although the observed growth-inhibiting effect was attributed to the high osmotic pressure of the salt solution, physiological effects depending on ion species used were also considered to be possible. The growth of all three types of fungi on copy paper was inhibited effectively when the salt concentration was increased. The growth of various fungi on pure cellulose, with enough oxygen supplied to pores, was completely inhibited (as assessed by visual examination) for 24 days at salt concentrations of 3.5% (m/m) or greater. The fact that the effect of saltwater on cellulosic materials was observed even under optimum medium conditions implies that fungi would be considerably inhibited on flood-damaged paper immersed in saltwater. This method is a promising first aid measure when circumstances do not allow for flood-damaged paper to be dried immediately.     

半导体硫化银纳米晶的控制合成与光学性能研究

在以C12E9为表面活性剂形成的反相胶束体系中,成功地合成出形状较规则、分布较均匀、平均粒径为42nm的半导体Ag2S纳米粒子.X射线衍射测定表明,产物纯度很高,具单斜结构.紫外-可见和荧光光谱发现,纳米材料与体相相比发生了显著地\"蓝移\".     

Identification of cellulose nitrate X-ray film for the purpose of conservation: Organic elemental analysis

Cellulose nitrate was widely used as a film base for photography, cinematography, and radiography in the first half of the twentieth century. Its stability is inherently poor and subject to environmental storage conditions. The risk of fire and the cross-infection effect on the cellulose acetate film stored at the same location necessitate that cellulose nitrate is identified within collections and stored separately. Not only medical archives, but also museums using radiography in their research may hold a sizeable amount of historical X-ray films. The Natural History Museum, London has been using film for X-radiography since before World War II. This suggests that some of the X-ray materials in its collections have a cellulose nitrate rather than ‘safety’ (cellulose acetate or polyester) film base. X-ray sheets rarely contain information related to their composition so science-based identification methods must be used. We propose the determination of nitrogen content in the film by organic elemental analysis (OEA) as a reliable method for the identification of films (X-ray, photographic, or cinematographic) with a cellulose nitrate base. Though it is a destructive method, the sample size required is small (<1?mg). This method does not require any sample preparation apart from weighing the samples and wrapping them in tin foil. OEA proved to be more accurate than the ‘float’ test in trichloroethylene and quicker and more straightforward to perform than infrared spectroscopy.     

纤维素表面活性剂的种类及应用

纤维素基表面活性剂因其原料丰富、可生物降解、使用安全和对环境友好等诸多优点,使其逐渐引起了人们的关注。文章综述了纤维素基表面活性剂的研究进展,并着重介绍了纤维素表面活性剂的种类及应用。     

纤维素吸水材料

文章简要综述了纤维素吸水材料的种类及研究进展。     

不同温度和pH值对瘤背石磺（Onchidium verruculatum Cuvier）消化酶活性的影响

研究了温度和pH值对瘤背石磺（Onchidium verruculatum Cuvier）肠淀粉酶、肝胰腺淀粉酶和胃淀粉酶以及相应的纤维素酶活性的影响．不同温度和pH值对瘤背石磺消化酶活性的影响显著（P〈0．05）．当温度在5—75℃时,肠淀粉酶和纤维素酶分别在35℃和30℃时活性较高;肝胰腺淀粉酶和纤维素酶分别在35—45℃和50℃时活性较高;胃淀粉酶活性在25—45℃维持较高水平,随后随温度的升高而下降,纤维素酶活性在50℃时较高．在pH为3．0—8．0范围内,肠淀粉酶和纤维素酶的最适pH值均为6．0;肝胰腺淀粉酶和纤维素酶的最适pH值分别为6．9和5．4;胃淀粉酶和纤维素酶的最适pH值分别为6．5和6．0．在适宜温度和pH条件下,肠淀粉酶、肝胰腺淀粉酶和胃淀粉酶活性均远大于肠纤维素酶、肝胰腺纤维素酶和胃纤维素酶．     

醋酸纤维素酯电影胶片贮存条件探讨

醋酸纤维素酯电影胶片是目前保存较多的一类电影胶片,由于自身构成材料与保存环境因素的影响,在使用与保存过程中容易出现霉变、褪色、醋酸综合症等病害现象,因此选择适宜的保存条件预防病害现象的发生对于保存醋酸纤维素酯电影胶片尤为重要.本文基于电影胶片的构成材料与保存环境对电影胶片的作用,探讨醋酸纤维素酯电影胶片适宜的保存条件.     

纤维素微球的制备及其应用

综述了纤维素微球的制备方法,介绍了纤维素微球在色谱分离、生物、医学、环保、材料等领域的应用。     

球状LaVO_4:Eu~(3+)纳米晶的水热合成及其荧光性能

以La2O3、Eu2O3、浓HNO3、氢氧化钠、Na VO3、无水乙醇、一缩二乙二醇为原料,采用聚乙烯吡咯烷酮(PVP)辅助水热法合成了La VO4:Eu3+纳米晶,并用X粉末衍射(XRD)、透射电镜(HRTEM)、红外光谱(IR)和荧光光谱(FL)对产品进行了表征和分析。测试结果表明,球状La VO4:Eu3+纳米晶在620nm处有较强的红光发射,溶液p H影响La VO4:Eu3+纳米晶的色纯度和发光强度,其中p H为5时样品的绿色纯度最好,而p H为8时的绿光发射最强。