Osmotically driven drug delivery through remote-controlled magnetic nanocomposite membranes     

A. Zaher  S. Li  K. T. Wolf  F. N. Pirmoradi  O. Yassine  L. Lin  N. M. Khashab  J. Kosel 《Biomicrofluidics》2015,9(5)

Implantable drug delivery systems can provide long-term reliability, controllability, and biocompatibility, and have been used in many applications, including cancer pain and non-malignant pain treatment. However, many of the available systems are limited to zero-order, inconsistent, or single burst event drug release. To address these limitations, we demonstrate prototypes of a remotely operated drug delivery device that offers controllability of drug release profiles, using osmotic pumping as a pressure source and magnetically triggered membranes as switchable on-demand valves. The membranes are made of either ethyl cellulose, or the proposed stronger cellulose acetate polymer, mixed with thermosensitive poly(N-isopropylacrylamide) hydrogel and superparamagnetic iron oxide particles. The prototype devices'' drug diffusion rates are on the order of 0.5–2 μg/h for higher release rate designs, and 12–40 ng/h for lower release rates, with maximum release ratios of 4.2 and 3.2, respectively. The devices exhibit increased drug delivery rates with higher osmotic pumping rates or with magnetically increased membrane porosity. Furthermore, by vapor deposition of a cyanoacrylate layer, a drastic reduction of the drug delivery rate from micrograms down to tens of nanograms per hour is achieved. By utilizing magnetic membranes as the valve-control mechanism, triggered remotely by means of induction heating, the demonstrated drug delivery devices benefit from having the power source external to the system, eliminating the need for a battery. These designs multiply the potential approaches towards increasing the on-demand controllability and customizability of drug delivery profiles in the expanding field of implantable drug delivery systems, with the future possibility of remotely controlling the pressure source.  相似文献   

Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation     

L. Yu  S. M. Grist  S. S. Nasseri  E. Cheng  Y.-C. E. Hwang  C. Ni  K. C. Cheung 《Biomicrofluidics》2015,9(2)

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.  相似文献   

Flipping the classroom to teach systematic reviews: the development of a continuing education course for librarians     

Marisa L. Conte  Mark P. MacEachern  Nandita S. Mani  Whitney A. Townsend  Judith E. Smith  Chase Masters  Caitlin Kelley 《Journal of the Medical Library Association》2015,103(2):69-73

Objective:The researchers used the flipped classroom model to develop and conduct a systematic review course for librarians.Setting:The research took place at an academic health sciences library.Method:A team of informationists developed and conducted a pilot course. Assessment informed changes to both course components; a second course addressed gaps in the pilot.Conclusion:The flipped classroom model can be successful in developing and implementing a course that is well rated by students.  相似文献   

Library resource discovery     

Michael R. Kronenfeld  Harold S. Bright  IV 《Journal of the Medical Library Association》2015,103(4):210-213

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#MeToo,sexual harassment: an article,a forum,and a dream for the future     

Robin Patric Clair  Nadia E. Brown  Debbie S. Dougherty  Hannah K. Delemeester  Patricia Geist-Martin  William I. Gorden 《Journal of Applied Communication Research》2019,47(2):111-129

#MeToo has breathed new life into the women’s movement and especially into understanding and rectifying sexual harassment, abuse and assault. It has galvanized activists around the globe. And it has placed thousands of stories of the harassed in full view of the public. Sexual harassment, abuse and assault may occur within the organizational context or beyond; but sexual harassment, in particular has been legally labeled an organizational phenomenon. With this in mind, Robin Clair frames the early part of this article around the most recent organizational communication theories (see the appendix for an overview of these theories). Following the essay is a forum, in which invited scholars address questions related to the #MeToo movement.  相似文献   

Block Talk: Spatial Language During Block Play     

Katrina Ferrara  Kathy Hirsh‐Pasek  Nora S. Newcombe  Roberta Michnick Golinkoff  Wendy Shallcross Lam 《Mind, Brain, and Education》2011,5(3):143-151

Spatial skills are a central component of intellect and show marked individual differences. There is evidence that variations in the spatial language young children hear, which directs their attention to important aspects of the spatial environment, may be one of the mechanisms that contributes to these differences. To investigate how play affects variations in language, parents and children were assigned to 1 of 3 conditions: free play with blocks, guided play, or play with preassembled structures (Study 1). Parents in the guided play condition produced significantly higher proportions of spatial talk than parents in the other two conditions, and children in the guided play condition produced significantly more spatial talk than those in the free play condition. Study 2 established baselines of spatial language during activities not involving spatial materials. Proportions of spatial words were lower than those in any of the conditions of Experiment 1. In sum, interaction with blocks naturally elicits elevated levels of spatial language, especially in the context of guided play, suggesting simple‐to‐execute educational interventions.  相似文献   

Infant Attachment Security and Early Childhood Behavioral Inhibition Interact to Predict Adolescent Social Anxiety Symptoms          下载免费PDF全文

Erin Lewis‐Morrarty  Kathryn A. Degnan  Andrea Chronis‐Tuscano  Daniel S. Pine  Heather A. Henderson  Nathan A. Fox 《Child development》2015,86(2):598-613

Insecure attachment and behavioral inhibition (BI) increase risk for internalizing problems, but few longitudinal studies have examined their interaction in predicting adolescent anxiety. This study included 165 adolescents (ages 14–17 years) selected based on their reactivity to novelty at 4 months. Infant attachment was assessed with the Strange Situation. Multimethod BI assessments were conducted across childhood. Adolescents and their parents independently reported on anxiety. The interaction of attachment and BI significantly predicted adolescent anxiety symptoms, such that BI and anxiety were only associated among adolescents with histories of insecure attachment. Exploratory analyses revealed that this effect was driven by insecure‐resistant attachment and that the association between BI and social anxiety was significant only for insecure males. Clinical implications are discussed.  相似文献   

Orville Vernon Burton (with Emory Campbell and Wilbur Cross). Penn Center: A History Preserved. Athens: University of Georgia Press, 2014. 190 pp. Cloth $40.00.          下载免费PDF全文

Jon N. Hale 《History of education quarterly》2015,55(4):491-494

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Nonideal Theory and Philosophy of Education: Considering What Is While Working Toward What Ought to Be          下载免费PDF全文

Michele S. Moses 《Educational theory》2015,65(2):107-110

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Student perceptions of effective instruction and the development of critical thinking: a replication and extension     

Chad N. Loes  Mark H. Salisbury  Ernest T. Pascarella 《Higher Education》2015,69(5):823-838

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