Ultrafast microfluidics using surface acoustic waves

We demonstrate that surface acoustic waves (SAWs), nanometer amplitude Rayleigh waves driven at megahertz order frequencies propagating on the surface of a piezoelectric substrate, offer a powerful method for driving a host of extremely fast microfluidic actuation and micro∕bioparticle manipulation schemes. We show that sessile drops can be translated rapidly on planar substrates or fluid can be pumped through microchannels at 1–10 cm∕s velocities, which are typically one to two orders quicker than that afforded by current microfluidic technologies. Through symmetry-breaking, azimuthal recirculation can be induced within the drop to drive strong inertial microcentrifugation for micromixing and particle concentration or separation. Similar micromixing strategies can be induced in the same microchannel in which fluid is pumped with the SAW by merely changing the SAW frequency to rapidly switch the uniform through-flow into a chaotic oscillatory flow by exploiting superpositioning of the irradiated sound waves from the sidewalls of the microchannel. If the flow is sufficiently quiescent, the nodes of the transverse standing wave that arises across the microchannel also allow for particle aggregation, and hence, sorting on nodal lines. In addition, the SAW also facilitates other microfluidic capabilities. For example, capillary waves excited at the free surface of a sessile drop by the SAW underneath it can be exploited for micro∕nanoparticle collection and sorting at nodal points or lines at low powers. At higher powers, the large accelerations off the substrate surface as the SAW propagates across drives rapid destabilization of the drop free surface giving rise to inertial liquid jets that persist over 1–2 cm in length or atomization of the entire drop to produce 1–10 μm monodispersed aerosol droplets, which can be exploited for ink-jet printing, mass spectrometry interfacing, or pulmonary drug delivery. The atomization of polymer∕protein solutions can also be used for the rapid synthesis of 150–200 nm polymer∕protein particles or biodegradable polymeric shells in which proteins, peptides, and other therapeutic molecules are encapsulated within for controlled release drug delivery. The atomization of thin films behind a translating drop containing polymer solutions also gives rise to long-range spatial ordering of regular polymer spots whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for polymer patterning without requiring surface treatment or physical∕chemical templating.     

Rapid production of protein-loaded biodegradable microparticles using surface acoustic waves

We present a straightforward and rapid surface acoustic wave (SAW) atomization-based technique for encapsulating proteins into 10 μm order particles composed of a biodegradable polymeric excipient, using bovine serum albumin (BSA) as an exemplar. Scans obtained from confocal microscopy provide qualitative proof of encapsulation and show the fluorescent conjugated protein to be distributed in a relatively uniform manner within the polymer shell. An ELISA assay of the collected particles demonstrates that the BSA survives the atomization, particle formation, and collection process with a yield of approximately 55%. The SAW atomization universally gave particles with a textured morphology, and increasing the frequency and polymer concentration generally gave smaller particles (to 3 μm average) with reduced porosity.     

Evaluation of immunohistochemistry and enzyme linked immunosorbent assay for HER-2/neu expression in breast carcinoma

HER-2 is overexpressed in approximately 20–30% of invasive Breast Cancer. ECD of the HER-2 protein is frequently cleaved and released into the circulation, where it can be detected by ELISA in up to 45% of patients with metastatic breast cancer. The objective of our study was to compare the current methods for the detection of HER-2 protein. Tissue HER-2 levels were studied in 100 breast cancer patients by IHC and compared with serum HER-2 levels by ELISA. IHC frequency was 29%. Serum HER-2 ECD was positive in 42% of patients. A statistically significant correlation was observed. HER-2 detected by IHC correlates significantly with serum HER-2 levels detected by ELISA. Thus, ELISA is a reliable and economical tool to assess the HER-2 status in tumors, when breast tissue sample is not available.     

The private finance initiative, project form and design innovation: The UK's hospitals programme

This paper discusses the role of public demand, in the form of a government procurement policy, in generating innovative solutions for healthcare infrastructure. It considers the effects of the project delivery system (planning, finance, construction and operation) for new hospitals on design innovation. It focuses on hospitals built under the UK's private finance initiative (PFI), which was partly introduced to inject increased innovation into hospital delivery. We use case studies of six early PFI hospitals to argue that the introduction of PFI has increased the complexity at the interface between project delivery and hospital operational functions. The result is a project delivery model which yields less innovative outcomes and produces facilities that might not be able to cope with future changes in demand. The paper suggests that new public procurement models do not automatically provide efficiency and innovation benefits.     

Research: Students' Perceptions of Need for Personal Counseling Services in Community Colleges

Although the need for personal counseling services is on the rise across college campuses in the United States, many community colleges do not offer personal counseling services on campus. Instead, community college counseling services focus primarily on academic and career advising. The purpose of this study was to survey community college students in North Carolina to determine their interest in and need for a personal counseling center on campus. Participants were 134 men and 202 women, 18–68 years of age. Of the participants, 70% indicated that having a personal counseling center on campus would be “very helpful” or “helpful.” Results are discussed, and recommendations are made for college counselors working in community college settings.     

Non-Traditional Students in Australian Higher Education: Persistent Inequities and the New Ideology of `Student Choice'

Despite the expansion of access toAustralian higher education in the past decade, theparticipation shares of rural and isolated people andpeople from lower socioeconomic backgrounds havealtered little and remain unacceptably low. Thispaper reports findings from two national studies atthe Centre for the Study of Higher Education that haveexamined student choices about higher education,especially the inhibiting factors still present fornon-traditional students. The discussion focuses onthe dilemmas and challenges for Australianuniversities in balancing the adoption ofentrepreneurial approaches to student recruitment withan unfinished equity agenda. The paper raisesquestions about the new ideology of individual choiceinfluencing university policy and whether or not thiscan be reconciled with social equity objectives.     

ISI数据库——学术期刊及网站的选择

ISI（美国科学信息研究所）的基本任务是向其用户提供所需要的世界最重要、最有影响的期刊收录信息,ISI数据库不仅可以检索当年而且可追溯以往。现有数据库收录自然科学、社会科学、艺术与人文科学的国际期刊8500余种。ISI能完整地检索它所收录的任何一条文献数据。期刊的评估与选择是动态过程,每年ISI数据库的来源期刊都会有所增加或删减。每种期刊在被录用或被淘汰前都经过内容广泛的评估过程。ISI数据库期刊评估要考虑多种因素,评估范围从质到量标准不同,包括基本出版标准、学术内容、作者的国际化程度,及其与之相关的引文     

谁改变了我们的常识?——美国教育保守主义运动与教育不平等

本文考察和分析了美国教育走向保守主义的趋势及其所引发的冲突和斗争。美国教育政策的保守趋势运动是多元的,存在着不同的取向,主要有四种力量构成新自由主义、新保守主义、威权民粹主义和正处在上升阶段的由专业人员和管理人员所构成的新中产阶级。本文侧重探讨了保守主义在改造美国教育的运动中居于领导地位的前两支力量,并认为在教育和社会政策领域,这些力量成功地构建成一个联盟,该联盟成功的重要原因在于对常识的改造,作者将之称为“保守主义的现代化”。