The effect of labels and instruction on concept attainment in the educable mentally retarded

The present experiment examined concept attainment in 80 educable mentally retarded and 80 normal boys of high and low mental age. The concept of an equilateral triangle was assessed following random exposure to one of four experimental conditions assessing the influence of verbal labels and instruction on the labels. A 2 × 2 × 4 multivariate analysis of variance revealed a significant effect of mental age; however, retarded and normal subjects did not differ in mean performance on any of the five dependent measures. The hypothesized treatment effect was significant at the formal level of concept attainment. The findings were discussed in terms of theoretical and educational implications.     

利用微生物转化维生素D3的研究(Ⅰ)--25(OH)D3的生物转化

根据目标菌株的生物学特征等筛选出若干菌株，还成功地利用入选菌株将维生素D3转化成为活性维生素D3——25(OH)D3，并采用已建立的薄层层析和高效液相色谱等检测方法对入选菌株的活性进行了鉴定。结果表明：放线菌菌株TN-955具有把维生素D3转化成为活性维生素D3——25(OH)D3的功能。     

An analysis of the vitamin D overtesting in a tertiary healthcare centre

IntroductionVitamin D testing is excessively used in clinical practice, despite of the clinical guidelines statements against population screening for vitamin D deficiency. This study aimed to assess an annual number of performed 25-hydroxy vitamin D (25(OH)D) tests that were unsupported by the national guidelines for prevention, detection and therapy of vitamin D deficiency in adults and to calculate associated financial burden for the publicly funded healthcare.Materials and methodsA representative sample of requested 25(OH)D tests in 2018 (N = 474) was formed after selection and randomisation of data set (N = 5298) collected from the laboratory information system database of the Clinical Department for Laboratory Diagnostics, the Clinical Hospital Centre Rijeka. Records were classified in two groups depending on associated medical condition(s) according to the national guidelines. An annual cost of the total and group specific vitamin D testing was calculated on the base of a single test price reimbursed by the Croatian Healthcare Insurance Fund (CHIF).ResultsMedical conditions with high-risk for vitamin D deficiency were detected in 43% (206/474) of vitamin D requests (group 1). Conditions not associated with vitamin D deficiency were detected in 57% (268/474) requests (group 2). A total cost of 25(OH)D testing for the CHIF was 58,729.50 EUR (25,523.79 EUR in the group 1 and 33,205.71 EUR in the group 2).ConclusionsMore than half of all 25(OH)D tests performed in the clinical laboratory represent avoidable cost for the public healthcare. Prevention of population screening by vitamin D testing is needed.     

探讨合成α-松油基醚的有利条件

α-松油基醚是α-pinene的烷氧基化产物,是一种单萜烯基醚。酸催化单萜烯与脂肪醇的烷氧基化反应得到单萜基醚是合成单萜基醚的一种方法,温度和溶剂都会影响α-松油基醚的生成,合成α-松油基醚的有利条件是:温度为50℃左右,不加溶剂CCl4。     

Fe(OH)_3胶体渗析半透膜制备研究

研究了Fe(OH)3胶体渗析半透膜的制备,主要从半透膜的层数和加入尿素的质量2个方面进行探究。实验结果表明:加入尿素的质量为2g,用两层的半透膜进行渗析时得到的Fe(OH)3胶体电泳实验现象最佳。     

二氧化硫脲/Ca（OH）2-铁氧体法处理铜铬电镀废水工艺

当二氧化硫脲用量是还原Cu^2＋为Cu与还原Cr^5＋为Cr^3＋理论值总和的两倍时,使用二氧化硫脲在石灰饱和溶液（pH≈12．8）、沸腾条件下处理铜铬电镀废水,废水中Cu^2＋从31mg／L降为0．4mg／L,Cr^5＋从23mg／L降为0．017mg／L,总铬量由35mg／L降为5．3mg／L,经分析沉淀物为Cu（黑色）、Cu2O、Cr（OH）3趁热过滤后,往滤液中加入FeSO4·7H2O,调节pH至中性,鼓入空气,冷却至得到黑色铁氧体沉淀．经处理后残铜量为0．2mg／L,总铬量为0．035mg／L,PO4^3-由5mg／L降为1mg／L．各项指标优于工业排放标准．     

Marine Aerosol Weathering of Mediterranean Calcarenite Stone: Durability of Ethyl Silicate,Nano Ca(OH)2, Nano SiO2, and Nanostructured Consolidating Products

ABSTRACT

Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol–gel, Ca(OH)₂, and SiO₂ nanoparticles. These were subjected to marine aerosol accelerated aging cycles and studied by several non-destructive tests and techniques to assess the stability of the products. Results show that weathering caused by salt crystallization is not inhibited but it is slowed down due to the enhancement of superficial mechanical properties (surface cohesion and micro-hardness) achieved after one month of treatments application. A high or low relative humidity of the consolidation environment significantly affects the final mechanical and aesthetical physical properties and therefore conditions the durability of the treated substrates, even producing higher damage than observed in the blank specimens, depending on the product.     

Multifunctional nanocomposites for paper conservation

Abstract

Upon aging, paper documents and books become progressively damaged. Paper deacidification is a fundamental conservation intervention. In this study, we report on the use of nanoparticles of titanium dioxide (TiO₂) and magnesium hydroxide (Mg(OH)₂) associated with hydroxyethylcellulose (HEC) to inhibit acidification, photo-induced degradation, and biodeterioration of paper. With the aid of ultrasound, Mg(OH)₂ nanoparticles with a narrow size distribution can be obtained through homogeneous precipitation in water. Furthermore, to demonstrate the efficacy of the nanocomposite and the performance of treated and untreated paper, photo- and thermal-induced degradation is discussed. The results show that using the controlled double-jet precipitation (CDJP) it is possible to synthesize Mg(OH)₂ particles with a narrow size distribution (18–87 nm). The nanocomposite of Mg(OH)₂–TiO₂–HEC increases the durability of paper by imparting fungal growth resistance (D = 34.6 mm), moderate alkalinity (pH = 8.4), mechanical reinforcement (from 817–896 N/m), and UV protection. Additionally, there is a slight color difference (ΔE* = 0.8) between the treated and untreated paper. Both photodegradation and thermal degradation indicate that the paper treated with this nanocomposite (Mg(OH)₂–TiO₂–HEC) has increased stability.     

Deacidification of paper using dispersions of Ca(OH)2 nanoparticles in isopropanol. Study of efficiency

The efficiency of a recently described non-aqueous method for paper deacidification using Ca(OH)₂ nanoparticles in isopropanol was evaluated by pH and colorimetric measurements and by the analysis of the degree of polymerization (DP). Samples of plain paper and paper with iron gall ink were tested. The results were compared with non treated samples and samples submitted to the traditional treatment with saturated aqueous Ca(OH)₂ solution. By comparing the two conservation methods, the aqueous one shows higher neutralization reaction kinetics than the non-aqueous one. The iron gall ink samples maintain their coloration closer to the original after the non-aqueous Ca(OH)₂ nanoparticles treatment, in contrary to the aqueous treatment that changes the ink aesthetics considerably. Artificial aging tests revealed a general increase in the aging stability of deacidified paper samples. The Ca(OH)₂ nanoparticles treatment can be an alternative for papers who can not be treated by the classical aqueous treatment, e.g. papers with water soluble components.     

木犀草素-Fe3+配合物及其自由基清除活性的研究

木犀草素这种黄酮类化合物能与多种金属形成配合物。本文用紫外-可见分光光度法研究了木犀草素与Fe3+的配位作用,并研究了木犀草素-Fe3+配合物清除羟自由基的能力。结果表明:在HAc-NH4Ac(pH=4.5)缓冲溶液中,木犀草素与Fe3+形成1:2的配合物,其条件稳定常数为1.9×1011,同时配合物有较强的清除羟自由基的活性。