Transport of particles and microorganisms in microfluidic channels using rectified ac electro-osmotic flow

A new method is demonstrated to transport particles, cells, and other microorganisms using rectified ac electro-osmotic flows in open microchannels. The rectified flow is obtained by synchronous zeta potential modulation with the driving potential in the microchannel. Experiments were conducted to transport both neutral, charged particles, and microorganisms of various sizes. A maximum speed of 50 μm∕s was obtained for 8 μm polystyrene beads, without any electrolysis, using a symmetrical square waveform driving electric field of 5 V∕mm at 10 Hz and a 360 V gate potential with its polarity synchronized with the driving potential (phase lag=0°).     

Organosilane deposition for microfluidic applications

Treatment of surfaces to change the interaction of fluids with them is a critical step in constructing useful microfluidics devices, especially those used in biological applications. Silanization, the generic term applied to the formation of organosilane monolayers on substrates, is both widely reported in the literature and troublesome in actual application for the uninitiated. These monolayers can be subsequently modified to produce a surface of a specific functionality. Here various organosilane deposition protocols and some application notes are provided as a basis for the novice reader to construct their own silanization procedures, and as a practical resource to a broader range of techniques even for the experienced user.     

我国省级公共图书馆数字参考咨询服务合作模式现状分析

通过对我国省级公共图书馆网站开展数字参考咨询服务合作情况的调研,发现各地区联合参考服务发展极不平衡,但是合作的成熟模式已逐渐凸现,而且跨地区、跨系统联合发展的趋势显现。提出积极开展合作、整合共享平台的发展建议。     

The Reciprocity of ‘Imitative Learning’ through Apprenticeship

Humans are proposed to have evolved to learn through observation, imitation and practice or mimesis. In this article, the contribution of imitation, as an important but poorly understood aspect of mimetic learning, is advocated to create affordances for dyadic learning. However, learning through imitation is often perceived with negative connotations perhaps framed by viewpoints individuals have derived from experiences of rote learning and repetitive work. Yet, learning through imitation plays a key role in the learning of skills, including many of the non-verbal communicative and tacit aspects of trades work. This article explores the ways trade apprentices learn, with emphasis on the contribution of imitation. Recommendations to improve the reciprocal relationships between mentor and apprentice, initiated and developed through learning by ‘imitation’, are discussed and considered.     

Children exposed to child maltreatment and intimate partner violence: a study of co-occurrence among Hong Kong Chinese families

Objective

This study assessed the co-occurrence of child maltreatment and intimate partner violence (IPV) and examined the association between them.

Method

The cross-sectional study recruited a population-based sample of 1,094 children aged 12-17 years in Hong Kong. Structured questionnaires were used to collect data from the children. The prevalence of occurrence of child abuse and neglect by parents and exposure to IPV in both the past year and lifetime was examined, and their correlates were assessed using univariate and multivariate logistic regression.

Results

The results show that 26% and 14.6% of child participants had been exposed to IPV physical assault, and 44.4% and 22.6% had been subjected to a parent's corporal punishment or to physical maltreatment from a parent in their lifetime and the year preceding the study, respectively. Among those families characterized by IPV, 54.4% and 46.5% were involved in child physical maltreatment over the child's lifetime and in the preceding year, respectively.

Conclusions

Multivariate logistic regression analyses revealed that children exposed to IPV were at higher risk of being victims of neglect, corporal punishment, and physical maltreatment or severe physical maltreatment by their parents than children who were not exposed to IPV, even when child and parent demographic factors were controlled for.

Practical implications

The higher risk of child physical maltreatment associated with IPV highlights the need for an integrated assessment to screen for the presence of multiple forms of family violence within the family, and for intervention to assess effective responses to both IPV and child maltreatment by child protective service workers and domestic violence agencies.     

Children's views on child abuse and neglect: findings from an exploratory study with Chinese children in Hong Kong

Objectives

This research study explored children's views on issues about child abuse in Hong Kong and examined their implications on child protection work and research in Chinese societies.

Method

Six primary schools were recruited from different districts of Hong Kong. Five vignettes of child maltreatment in the form of flash movies were presented to 87 children in 12 focus groups for discussion. The process was video-taped and the data were transcribed verbatim for data analysis by NUDIST.

Results

(1) Children do not have a homogeneous view on issues about child abuse and neglect, and their awareness and sensitivity to different kinds of child abuse are also different; (2) some of their views on child abuse and neglect are uniquely their own and are markedly different from those of adults; (3) some of the views expressed by children, however, are very much akin to those of adults, such as the factors they would consider in deciding whether a case is child abuse or not; (4) children's disclosure of abuse in Hong Kong is often affected by the Chinese culture in which they live, like filial piety and loyalty to parents.

Conclusion

Children's views on issues of child abuse and neglect, no matter they are the same or different from those of adults, serve to inform and improve child protection work. Children are not only victims in need of protection. They are also valuable partners with whom adult practitioners should closely work.

Practice implications

Children have, and are able to give, views on child abuse. They should be listened to in any child protection work no matter their views are same with or different from those of adults. As this study suggests, the relatively low sensitivity of the children to child neglect and sexual abuse, and their reluctance to disclose abuse and neglect due to their loyalty to parents are areas to focus on in preventive child protection work in a Chinese society like Hong Kong.     

Image–language interaction in online reading environments: challenges for students’ reading comprehension

This paper presents the qualitative results of a study of students’ reading of multimodal texts in an interactive, online environment. The study forms part of a larger project which addressed image–language interaction as an important dimension of language pedagogy and assessment for students growing up in a multimedia digital age. Thirty-two Year 6 students representing a sample of high, medium and low performers on an Australian state-wide school literacy test were surveyed about their internet usage and interviewed using a structured protocol while working online through a selection of materials from an educational website. Findings from the earlier stages of the project indicated that different types of image-text relations vary in the degree of difficulty they pose for students’ reading comprehension. This phase of the project extended the analysis of image-text relations to online, interactive texts. Student performance on online reading tasks and interview data are used to illustrate some of the complexities students encounter when reading online, and how this may vary with factors such as their day-to-day literacy experiences and levels of engagement. The results have implications for literacy pedagogy and assessing the reading of web-based texts.     

劳伦斯的生态哲思与上海世博园生态智慧的契合

戴.赫.劳伦斯是20世纪英国乃至世界文坛最具独创性,也最具争议性的作家之一,他的作品所蕴含的生态哲思为探寻一条自然、人类、社会和谐共存共荣的可持续发展之路提供了帮助。2010上海世博会在和谐的环境中进行沟通与交流,表达了人类应对未来城市化挑战的和谐整体生态智慧,也彰显了人类文明的终极追求——"和谐城市,宜居生活"。劳伦斯的生态哲思与上海世博园生态智慧存在某种程度上的契合。