严寒环境下排水管线施工方法

严寒环境下排水管道施工问题一直是困扰施工单位和建设单位的一大难题。作者在长期的施工和设计工作中,总结出以下严寒环境下排水管线施工方法,即管道的防腐、焊接、检查井井盖等重点施工项目集中保护处理;管沟开挖、回填及管道闭水试验快速处理;检查井及检查井进出水管制作及连接特殊处理的方法,从而保证整个工程施工质量合格,并且节省工程费用,保障施工单位和建设单位的经济利益不受损失。     

国产HW2000型高频红外碳硫仪分析精度探讨

对国产HW2000型高频红外碳硫仪的分析精度进行了测定,并与进口EMIA-620型高频红外碳硫仪进行了比较,结果表明,HW2000型红外仪的检出限低(0.000 03％).对3种标准样品的分析,HW2000型红外仪分析的碳的RSD为0.000 59％～ 1.630 25％,硫的RSD为0.012 67％ ～ 0.513 20％:而EMIA-620型分析的碳的RSD为0.206 64％～ 1.724 17％,硫的RSD为0.025 30％～0.939 15％.而且HW2000型红外仪有较好的分析线性.     

Tweens' characterization of digital technologies

The tweens are a transitional age group undergoing deep physical and psychological transformations. Based on a thirteen-focus group research design involving 103 students, and applying a tweens-centered approach, the characteristics of SMS, IM, Internet, digital photos, electronic games, and email were analyzed. Categories such as moral issues, psychological and social consequences, problems/drawbacks, general benefits, and technical attributes synthesized the main characteristics attached to each form of digital technology. Their relative relevance was not gender dependent. Furthermore, tweens exhibited both metacognitive knowledge and personal epistemological observations associated with most of the digital technologies.     

An attitude scale for smart board use in education: Validity and reliability studies

The main purpose of this study was to develop an instrument to measure the attitudes of elementary students towards smart board (SB) use in education. A sequential exploratory mixed method was used. So the study started with a qualitative approach to establish the content and face validity of the scale, followed by a quantitative approach to test the construct validity and reliability of the scale items. Ten students, one teacher trainer specialized in SB use, three teachers experienced in SB use, and a language expert participated in the qualitative part. Data from 203 elementary students from two local schools in Malatya, Turkey, were used to test the psychometric properties of ‘smart board attitude scale’ (SBAS). The exploratory factor analysis (FA) yielded a two-factor model with 10 items. The goodness of fit indices produced by confirmatory FA confirmed the fit of the model to the data. Reliability of SBAS was also proved through multi-analyses.     

A cognitive component analysis approach for developing game-based spatial learning tools

Spatial ability has been recognized as one of the most important factors affecting the mathematical performance of students. Previous studies on spatial learning have mainly focused on developing strategies to shorten the problem-solving time of learners for very specific learning tasks. Such an approach usually has limited effects on improving the mathematical performance of students. In this study, a cognitive analysis approach is proposed for developing spatial learning tools by taking game characteristics into consideration. Moreover, the validation of the cognitive components of the spatial sense test for constructing two different kinds of intervention is verified, and the effects of the interventions are compared. To evaluate the performance of the proposed approach, an experiment was conducted on the mathematics course of an elementary school. The experimental results show that the spatial learning tool promotes not only the learning achievement, but also the spatial sense of the students.     

Orthogonal ligation to spherical polymeric microparticles: Modular approaches for surface tailoring

Modular ligation strategies for the functionalization of polymeric microspheres provide new perspectives for their applications in material science. In the current trend article we highlight variable synthetic procedures for generating functional microspheres via orthogonal modular conjugation chemistries. An overview of the different surface chemistries available is provided, followed by surface-sensitive characterization techniques relevant for the microparticles. Finally, we explore future trends in modular orthogonal modification approaches on microparticles and provide an outlook on the perspectives that the field of surface-modification of polymeric microparticles holds.     

Incorporation of HSA Microparticles Within the Taxol-Loaded In Situ Forming PLGA Microspheres: Synthesis,Characterization, and Drug Release

Taxol-loaded poly(lactic acid-co-glycolic acid) (PLGA) microspheres containing different portions of human serum albumin microparticles (mHSA) were prepared via an in situ forming method. mHSA was obtained using a freezing-induced phase separation method and further surface modified via PLGA chains (g-mHSA). Surface modification of mHSA improved their dispersion within microspheres. Incorporation of 3% mHSA within microspheres increased their size and surface porosity, while g-mHSA decreased their size. Addition of 1.5% and 3% mHSA into microspheres decreased their initial burst release from 40.7% to 21.1% and 10.2%, respectively. Microspheres consisting 1.5% and 3% g-mHSA displayed 29.9% and 33.1% initial burst release, respectively.     

Preparation of Functionalized Polymersomes and the In Vivo Imaging

Recently, polymersomes self-assembled from amphiphilic block copolymers have attracted considerable interests with superior physicochemical properties. Here, the biotinylated block copolymers were blended with unmodified block copolymers to produce biotinylated polymersomes via film rehydration. Then, the avidin molecules were attached onto the biotin molecules covalently linked with block copolymers to form surface functionalized vesicles that are capable of carrying various biotinylated bioactive molecules, generating a relatively universal delivery platform. Hydrophobic fluorophores DAF and Nile Red were encapsulated respectively into hydrophobic membrane to prepare hydrophobic substances loaded polymersomes for investigating the nature of hydrophobic functionalization. Furthermore, the hydrophobic functionalized DiR-polymersomes were employed to perform in vivo imaging to survey the in vivo behavior for nano-polymersomes with hydrophobic functionalization.     

In Situ Forming Hydrogel Based on Chondroitin Sulfate–Hydroxyapatite for Bone Tissue Engineering

In this research, tissue engineered hydrogels consist of chondroitin sulfate and hydroxyapatite capable of light curing and cell encapsulation were prepared. Chemical and physical characteristics were analyzed by FTIR spectroscopy, compressive strength and water uptake measurements. Observations with fluorescence microscopy as well as MTT viability assay revealed no toxicity for encapsulated cells. Moreover, alkaline phosphatase activity, calcium deposition, and gene expression analysis were determined to prove the osteogenic potential of the prepared hydrogel. In conclusion, this in situ forming hydrogel can be utilized as filler for bone deficiencies as well as carrier for cell encapsulation and osteogenic differentiation.