Preface to Special Topic: Microfluidics in Drug Delivery     

Brigitte Stadler 《Biomicrofluidics》2015,9(5)

In this special topic of Biomicrofluidics, the importance of microfluidics in the field of drug delivery is highlighted. Different aspects from cell-drug carrier interactions, delivery vehicle assembly to novel drug delivery devices are considered. The contributing reviews and original articles illustrate the synergistic outcomes between these two areas of research with the aim to have a positive impact on biomedical applications.Microfluidics is certainly one of the huge success stories when it comes to anticipated impact and fulfilled promises in academic research environments. Microfluidic approaches are game changers in many disciplines in natural science, including (bio)medical science. In the latter case, the fields of biosensing/diagnostics, tissue engineering, and drug discovery/delivery have benefited from concepts which allow for the fast throughput manipulation of fluids at the submillimeter length scale.A key aim in microfluidic-assisted drug discovery is the development of strategies which will facilitate the identification of potential “hits”—new drugs with the anticipated therapeutic benefit. In this context, “organ(disease)-on-chips” are considered as highly sophisticated in vitro models with lower cost and less ethical issues compared to extensive testing in animals. This technology is still very young with countless research challenges to be addressed and eventually overcome, but the few current reports are promising, and include “gut-on-chip,” “cancer-on-chip,” or “blood vessel-on-chip.” Additionally, intravenously injected drug delivery vehicles are exposed to the blood stream and the induced mechanical forces which are likely to affect their interaction with cells and tissue. Therefore, understanding the diffusion phenomena of biomolecules in microfluidic devices as reviewed by Yesil-Celiktas and coworkers in the current special content is crucial.¹ What is more, the contribution by Hosta-Rigau and colleagues provides a comprehensive overview over the interaction of drug carriers and cells in microfluidic-based systems which deliver a simple, but yet more realistic model of the dynamic in vivo situation.² Further, to illustrate the relevance of shear stress when assessing the potential of nanocarriers for drug delivery applications, we assembled novel block copolymers consisting of poly(cholesteryl acrylate) as the hydrophobic core and poly(N-isopropylacrylamide) as the hydrophilic extensions together with lipids into vesicles using the evaporation-rehydration method.³ Following on, we biologically evaluated the assemblies with applied shear stress using macrophages. In a related report by the Chakraborty group, a biocompatible acoustic microfluidic system was outlined including the effect of microbubbles with the applied acoustic field on biological cells.⁴From a different perspective, droplet microfluidics has become a popular method to assemble a huge diversity of particles of different size, shape, and morphology equipped with options for active or passive drug release. Microfluidics provides unique opportunities and flexibility to fabricate decent amounts of mono-disperse drug carriers using monomers, polymers, lipids, or inorganic precursor materials as building blocks. The assembly of size-tunable polymer/lipid particles by Sun et al.,⁵ and the fabrication of poly (lactic-co-glycolic acid) nanoparticles incorporated within poly (ethylene glycol) (PEG) microgels by the Chen group,⁶ provide interesting examples in this context. Further, artefacts associated with this technique have to be addressed and understood to avoid inaccurate and misleading data as reported by Litten et al.⁷ Microfluidic techniques can also be employed for cell encapsulation. Fan et al. demonstrated the trapping of human colon cancer cells in hydrogel particles with preserved viability and response to inflammatory stimuli.⁸Novel drug delivery devices which consider microfluidic concepts and set-ups are an interesting addition to traditional approaches. Implantable drug delivery systems provide an alternative to ensure constant drug level in blood without relying on the compliance of the patient while circumventing challenges involved in oral drug delivery coming from drug instability or limited absorbance among others. Yi and coworkers propose a reservoir approach in combination with a heat responsive valve towards the long term delivery of solid drugs.⁹ What is more, nebulizers, as alternative to inhalers for pulmonary drug delivery, suffer from miniaturization and drug degradation issues. Cortez-Jugo et al. report on a novel portable acoustomicrofluidic device, which successfully nebulized monoclonal antibodies into a fine aerosol mist including the first positive biological evaluation.¹⁰Further, combining microfluidics with sensing concepts as illustrated by Knoll and coworker¹¹ is of importance, since the design of drug delivery vehicles strongly relies on the fundamental understanding of the interaction between biomolecules, cells, and tissue.Taken together, these articles give an overview over the use of microfluidics in the area of drug delivery, which goes beyond the assembly of drug carries, but also provides a platform for their biological evaluation or the design of entirely new drug delivery devices. I hope that this collection of articles will stimulate new ideas and future collaborations between engineers/chemists/physicist and biologists towards the common goal to provide solutions for biomedical challenges. Finally, I would like to thank Professor Leslie Yeo for the invitation to be the guest editor for this special topic, and Christine Urso and other editorial and production staffs of Biomicrofluidics for making it a reality.  相似文献   

Digital body preservation: Technique and applications     

Vicky Vandenbossche  Joris Van de Velde  Stind Avet  Wouter Willaert  Stian Soltvedt  Noeska Smit  Emmanuel Audenaert 《Anatomical sciences education》2022,15(4):731-744

High-fidelity anatomical models can be produced with three-dimensional (3D) scanning techniques and as such be digitally preserved, archived, and subsequently rendered through various media. Here, a novel methodology—digital body preservation—is presented for combining and matching scan geometry with radiographic imaging. The technique encompasses joining layers of 3D surface scans in an anatomical correct spatial relationship. To do so, a computed tomography (CT) volume is used as template to join and merge different surface scan geometries by means of nonrigid registration into a single environment. In addition, the use and applicability of the generated 3D models in digital learning modalities is presented. Finally, as computational expense is usually the main bottleneck in extended 3D applications, the influence of mesh simplification in combination with texture mapping on the quality of 3D models was investigated. The physical fidelity of the simplified meshes was evaluated in relation to their resolution and with respect to key anatomical features. Large- and medium-scale features were well preserved despite extensive 3D mesh simplification. Subtle fine-scale features, particular in curved areas demonstrated the major limitation to extensive mesh size reduction. Depending on the local topography, workable mesh sizes ranging from 10% to 3% of the original size could be obtained, making them usable in various learning applications and environments.  相似文献   

Effects of a rubric for mathematical reasoning on teaching and learning in primary school     

Robbert Smit  Patricia Bachmann  Verena Blum  Thomas Birri  Kurt Hess 《Instructional Science》2017,45(5):603-622

Rubrics are assessment tools that help students gain complex competencies. Our quasi-experimental study aimed to evaluate whether rubrics help teachers teach and assess mathematical reasoning in primary school and whether such an instrument might support student learning. In two Swiss cantons, 762 students in 44 5th- and 6th-grade primary classes worked on their reasoning competencies, and half of them additionally employed our standards-based rubric. All of the teachers received a 1-day training and participated in the final project evaluation. To standardise and support the teachers during the implementation phase, they received a detailed curriculum. An achievement test and questionnaires for students and teachers were administered before and at the end of the intervention. The results of our quantitative longitudinal analyses indicate that the rubric fosters the teachers’ perceived diagnostic skills but only indirectly impacts their use of formative feedback. Based on the students’ perceptions, however, we observed a direct effect of the rubric on formative feedback and student self-assessment. Effects on students’ outcomes could not be observed, but there are indications of effects mediated by self-regulation and self-efficacy.  相似文献   

The disease burden of childhood adversities in adults: a population-based study     

Cuijpers P  Smit F  Unger F  Stikkelbroek Y  Ten Have M  de Graaf R 《Child abuse & neglect》2011,35(11):937-945

Objectives

There is much evidence showing that childhood adversities have considerable effects on the mental and physical health of adults. It could be assumed therefore, that the disease burden of childhood adversities is high. It has not yet been examined, however, whether this is true.

Method

We used data of a large representative sample (N = 7,076) of the general population in the Netherlands. We calculated the disability weight (DW) for each respondent. The DW is a weight factor that reflects the severity of a disease or condition on a scale from 0 (perfect health) to 1 (equivalent to death). We used an algorithm based on the SF-6D to estimate DW. Because the DW indicates the proportion of a healthy life year that is reduced by the specific health state of the individual, it also possible to calculate the total number of years lost due to disability (YLD) in the population. We calculated the years lived with disability (YLD) for 9 different childhood adversities (in the areas of parental psychopathology; abuse and neglect; major life events), as well as for major categories of mental disorders and general medical disorders.

Results

All 9 adversities resulted in a significantly increased DW, except death of a parent before the age of 16. Adversities in the category of abuse and neglect are associated with the highest DWs (0.057), followed by parental psychopathology (0.031) and life events during childhood (0.012). All adversities (46.4% of the population reports one or more adversity) are associated with 20.7 YLD/1,000, which is more than all mental disorders together (12.9 YLD/1,000). The category of abuse/neglect has the highest YLD/1,000 (15.8), which is also higher than all mental disorders together. Adjustment for the presence of mental and general medical disorders resulted in comparable outcomes.

Conclusions

Childhood adversities are more important from a public health point of view than all common mental disorders together, and should be a priority for public health interventions.  相似文献   

Related Multiscreening as a Strategy to Retain Audiences and Increase Persuasion During a Commercial Break     

Claire M. Segijn  Theo Araujo  Hilde A. M. Voorveld  Edith G. Smit 《广播与电子媒介杂志》2020,64(1):41-61

The aim of the study was to deepen our understanding of how related multiscreening affects audience memory and persuasion. A survey was administered after a live television show. The results showed that the higher the perceived relatedness of the multi-screen activity, the more persuasive the message. This effect was mediated by subsequent attention to television content, program involvement, and attention to the commercial break. The model was replicated for three different multiscreen activities: social media use, chatting, and information search. Furthermore, it was found that related multiscreening increased the likelihood of respondents staying tuned to the television after the show.  相似文献   

IMPROVING TEACHING AND LEARNING IN AFRICAN UNIVERSITIES ‐‐ STAFF (FACULTY) DEVELOPMENT PROGRAMMES AS A FIELD OF CO‐OPERATION BETWEEN EUROPEAN AND AFRICAN UNIVERSITIES     

Brigitte Berendt 《Higher Education in Europe》1989,14(2):69-75

In virtually all the countries of the world, the need for staff‐development programmes for university and other higher education teachers has been recognized. Because the developed countries of Europe and of North America have a head start in the domain, specialists from these countries have frequently been called upon to create and to offer staff‐development programmes in the universities of developing countries. This article discusses the appropriateness of European conceptions of staff‐development for African universities. Concluding that Euro‐centric staff‐developers and pre‐packaged European programmes are not appropriate, that they run the risk of becoming a form of cultural neo‐colonialism, the author considers ways in which European specialists can collaborate with their African colleagues in the structuring of staff‐development programmes that are not only African‐centred but are geared to the real needs of African universities as they are perceived by Africans themselves. If the author's suggestions are accepted, African universities will be able to make use of those aspects of European staff‐development concepts and programmes which have universal value without having to accept European cultural tutelage along with them.  相似文献   

National Assessments: Underlying Cultural Values Revealed by Comparing English and French National Tests     

Claire Planel  Patricia Broadfoot  Marilyn Osborn  Keith Sharpe  & Brigitte Ward 《European Journal of Education》2000,35(3):361-374

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Infants' Reliance on a Social Criterion for Establishing Word-Object Relations   总被引：3，自引：0，他引：3  

Dare A. Baldwin  Ellen M. Markman  Brigitte Bill  Renee N. Desjardins  Jane M. Irwin  Glynnis Tidball 《Child development》1996,67(6):3135-3153

The language children hear presents them with a multitude of co-occurrences between words and things in the world, and they must repeatedly determine which among these manifold co-occurrences is relevant. Social factors—such as cues regarding the speaker's referential intent—might serve as one guide to whether word-object covariation should be registered. In 2 studies, infants (15–20 months and 18–20 months in Studies 1 and 2, respectively) heard novel labels at a time when they were investigating a single novel object; in one case the label was uttered by a speaker seated within the infant's view and displaying concurrent attention to the novel toy (coupled condition), whereas in the other case the label emanated from a speaker seated out of the infant's view (decoupled condition). In both studies, subsequent comprehension questions indicated that infants of 18–20 months registered a stable link between label and object in the coupled condition, but not in the decoupled condition, despite the fact that covariation between label and object was equivalent in the 2 conditions. Thus, by 18–20 months children are inclined to establish a mapping between word and object only when a speaker displays signs of referring to that object.  相似文献   

The impact of learner characteristics on information utilization strategies, cognitive load experienced, and performance in hypermedia learning   总被引：3，自引：3，他引：0  

Katharina Scheiter  Peter Gerjets  Brigitte Vollmann  Richard Catrambone 《Learning and Instruction》2009,19(5):387-401

Against the background of an adaptation of Cognitive Load Theory to learner-controlled settings we investigated the impact of learner characteristics on information utilization strategies, cognitive load, and learning outcomes in a hypermedia environment. Based on the data of 79 students, five clusters of students were identified according to their learner characteristics by means of a cluster analysis. Further analyses showed that learners with more favorable characteristics (i.e., higher prior knowledge, more complex epistemological beliefs, more positive attitudes towards mathematics, better cognitive and metacognitive strategy use) tended to show a more adaptive example utilization behavior, reported less cognitive load, and solved more problems correctly than learners with less favorable characteristics.  相似文献   

静静的夕阳     

竹茱 《英语沙龙》2010,(2)

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