Osmotically driven drug delivery through remote-controlled magnetic nanocomposite membranes

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.     

A Comprehensive Analysis of High School Genetics Standards: Are States Keeping Pace with Modern Genetics?

Science education in the United States will increasingly be driven by testing and accountability requirements, such as those mandated by the No Child Left Behind Act, which rely heavily on learning outcomes, or "standards," that are currently developed on a state-by-state basis. Those standards, in turn, drive curriculum and instruction. Given the importance of standards to teaching and learning, we investigated the quality of life sciences/biology standards with respect to genetics for all 50 states and the District of Columbia, using core concepts developed by the American Society of Human Genetics as normative benchmarks. Our results indicate that the states' genetics standards, in general, are poor, with more than 85% of the states receiving overall scores of Inadequate. In particular, the standards in virtually every state have failed to keep pace with changes in the discipline as it has become genomic in scope, omitting concepts related to genetic complexity, the importance of environment to phenotypic variation, differential gene expression, and the differences between inherited and somatic genetic disease. Clearer, more comprehensive genetics standards are likely to benefit genetics instruction and learning, help prepare future genetics researchers, and contribute to the genetic literacy of the U.S. citizenry.     

拯救生命的给予

大多数的人总是倾向于临渴挖井而非居安思危,总觉得那些不幸之事不会降临到自己身上,但是大家有没有想过,也许有一天躺在病床上苦苦等待别人救助的会变成我们自己或者我们亲友?我是那些幸运儿之一,现在轮到我去帮助别人了。我最近进行了一次奇妙的旅行,刚从南非的德班回来,我在那里参加了第19届世界移植运动会。自1996年起,我就一直有参加这个移植运动会。无论怎么看,我     

Modifications of Recognition Memory Processes in Preterm Children: An Event‐Related Potential Study

Prematurity may cause hippocampal compromise. Therefore, hippocampus‐dependent memory processes (recollection‐based retrieval) may be more impaired than hippocampus‐independent processes (familiarity‐based retrieval). The memory of 18 children born preterm with reduced hippocampal volumes, without neonatal complications (weeks of gestation < 34, weight < 1,600 g), and 15 controls (8–10 years) was tested using an item recognition task. While groups were equal in memory performance, dissociation was found: The event‐related potential (ERP) correlate of familiarity was intact in the preterm group, whereas the correlate of recollection was attenuated. A follow‐up experiment ruled out that this was due to general cognitive deficits. Furthermore, gestational age correlated with the ERP index of recollection. Thus, recognition memory in preterm children may be characterized by a compensation of attenuated recollection by familiarity.     

Finding knowledge on the Internet: implications for the knowledge-driven curriculum

This article offers a critique of Michael Young’s perspective on the Internet as it relates to the knowledge-driven curriculum he supports. I argue that the Internet is a site of both theoretical knowledge and everyday concepts which challenges the differentiation of knowledge that premises much of Young’s writing. Google searches from the perspective of a student and teacher show that theoretical knowledge with vertical links to subject and disciplinary communities as well as coherence built through links between concepts is fairly readily accessed on the Internet. The importance of information literacy for students, the critical need to curate content on the web, as well as the implications for the curriculum of framing ‘knowing’ as encompassing ‘being familiar’ and comprehending’ are highlighted.     

University–preschool partnership and workplace-based learning: a collaborative ‘third space’ or no space at all?

The article examines the aims of the workplace-based learning of prospective preschool teachers in Iceland and associated cooperative practices between the University of Iceland and preschools. A ‘third space’ of collaboration between these two sites is considered necessary if the education of preschool student teachers is to be effective. Collaboration between the university and preschools as presented in the university’s policy documents and as implemented in practice will be investigated and compared to the literature on collective third space. Implications for both policy and practice are discussed.     

Modeling Growth in Electronic Learning Environments Using a Longitudinal Random Item Response Model

In educational environments, monitoring persons' progress over time may help teachers to evaluate the effectiveness of their teaching procedures. Electronic learning environments are increasingly being used as part of formal education and resulting datasets can be used to understand and to improve the environment. This study presents longitudinal models based on the item response theory (IRT) for measuring persons' ability within and between study sessions in data from web-based learning environments. Two empirical examples are used to illustrate the presented models. Results show that by incorporating time spent within- and between-study sessions into an IRT model; one is able to track changes in ability of a population of persons or for groups of persons at any time of the learning process.     

Examining the Rule of Thumb of Not Using Multilevel Modeling: The “Design Effect Smaller Than Two” Rule

Educational researchers commonly use the rule of thumb of “design effect smaller than 2” as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models (which differ in the location of the clustering effect). With a 3 (design effect) × 5 (cluster size) × 4 (number of clusters) Monte Carlo simulation study we found that the rule should not be applied when researchers: (a) are interested in the effects of higher-level predictors, or (b) have a cluster size less than 10. Implications of the findings and limitations of the study are discussed.