151 research outputs found
Examining Studentsâ Perceptions About an Adaptive-Responsive Online Homework System and its Influence on Motivation and Learning
Advances in technological education have made online homework an integral part of science courses in general which is especially true for general chemistry courses. Online homework, if used correctly, has the potential to improve studentsâ experience, and learning and performance in general chemistry courses. The purpose of this research investigation is to study studentsâ levels of perceptions about an adaptive-responsive online homework in terms of (1) examining studentsâ motivation, learning, and understanding of concepts, (2) determining the aspects of adaptive-responsive online homework that are useful to studentsâ learning, and (3) understanding the features in online homework that causes improvement in studentsâ motivation. The investigation took place at an urban, commuter, minority serving, and public college. The study subjects were recruited from student enrolled in general chemistry courses consisting of 207 research participants (N = 207). Our data suggest that students display positive levels of perceptions about the adaptive-responsive online homework and its use. Students also hold perceptions that show positive attitudes towards the online homework system and that it positively affected their motivation. Also, students list several useful aspects of the online homework system such as explanations of concepts, knowledge checks, review questions for tests, and tutorials. The adaptive-responsive online homework, according to the participants in our study, helped motivate students by helping them learn the concepts, continuously assessing their learning, checking their knowledge, and updating the topics accordingly
Tuning the endocytosis mechanism of Zr-based metalâorganic frameworks through linker functionalization
A critical bottleneck for the use of metal-organic frameworks (MOFs) as drug delivery systems has been allowing them to reach their intracellular targets without being degraded in the acidic environment of the lysosomes. Cells take up particles by endocytosis through multiple biochemical pathways, and the fate of these particles depends on these routes of entry. Here, we show the effect of functional group incorporation into a series of Zr-based MOFs on their endocytosis mechanisms, allowing us to design an effi-cient drug delivery system. In particular, naphthalene-2,6-dicarboxylic acid and 4,4'-biphenyldicarboxylic acid ligands promote entry through the caveolin-pathway, allowing the particles to avoid lysosomal degradation and be delivered into the cytosol, en-hancing their therapeutic activity when loaded with drugs
A Combination of Approved Antibodies Overcomes Resistance of Lung Cancer to Osimertinib by Blocking Bypass Pathways.
<b>Purpose:</b> Because of emergence of resistance to osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), no targeted treatments are available for patients with lung cancer who lose sensitivity due to new mutations or bypass mechanisms. We examined in animals and <i>in vitro</i> an alternative therapeutic approach making use of antibodies. <b>Experimental Design:</b> An osimertinib-sensitive animal model of lung cancer, which rapidly develops drug resistance, has been employed. To overcome compensatory hyperactivation of ERK, which we previously reported, an anti-EGFR antibody (cetuximab) was combined with other antibodies, as well as with a subtherapeutic dose of osimertinib, and cancer cell apoptosis was assayed. <b>Results:</b> Our animal studies identified a combination of three clinically approved drugs, cetuximab, trastuzumab (an anti-HER2 mAb), and osimertinib (low dose), as an effective and long-lasting treatment that is able to prevent onset of resistance to osimertinib. A continuous schedule of concurrent treatment was sufficient for effective tumor inhibition and for prevention of relapses. Studies employing cultured cells and analyses of tumor extracts indicated that the combination of two mAbs and a subtherapeutic TKI dose sorted EGFR and HER2 for degradation; cooperatively enhanced apoptosis; inhibited activation of ERK; and reduced abundance of several bypass proteins, namely MET, AXL, and HER3. <b>Conclusions:</b> Our <i>in vitro</i> assays and animal studies identified an effective combination of clinically approved drugs that might overcome resistance to irreversible TKIs in clinical settings. The results we present attribute the long-lasting effect of the drug combination to simultaneous blockade of several well-characterized mechanisms of drug resistance. <i>Clin Cancer Res; 24(22); 5610-21. ©2018 AACR</i> <i>See related commentary by Fan and Yu, p. 5499</i>
Characterization of three pyranose dehydrogenase isoforms from the litter-decomposing basidiomycete Leucoagaricus meleagris (syn. Agaricus meleagris)
From short-term store to multicomponent working memory: The role of the modal model
The term âmodal modelâ reflects the importance of Atkinson and Shiffrinâs paper in capturing the major developments in the cognitive psychology of memory that were achieved over the previous decade, providing an integrated framework that has formed the basis for many future developments. The fact that it is still the most cited model from that period some 50 years later has, we suggest, implications for the model itself and for theorising in psychology more generally. We review the essential foundations of the model before going on to discuss briefly the way in which one of its components, the short-term store, had influenced our own concept of a multicomponent working memory. This is followed by a discussion of recent claims that the concept of a short-term store be replaced by an interpretation in terms of activated long-term memory. We present several reasons to question these proposals. We conclude with a brief discussion of the implications of the longevity of the modal model for styles of theorising in cognitive psychology
Examining Some of the Students' Challenges in Learning Organic Chemistry
Organic chemistry is often regarded as a difficult subject which deters learners and is associated with poor performance. Our research aims to examine some of the challenges that students face in learning organic chemistry topics related to acid/base and resonance structures theories. For this purpose, organic chemistry exams were analyzed in regards to these troublesome topics. A questionnaire was administered to further understand some of the challenges students face when enrolled in organic chemistry. Our data show that students face several challenges learning these topics and that there is a need to change the way these topics are addressed in instruction
Examining Some of the Students' Challenges and Alternative Conceptions in Learning About Acid-base Titrations
Chemical equilibria, including acid-base equilibria, play a significant role in the learning of general chemistry. Acid-base reactions as well as acidity and basicity concepts and their relationship to titrations are an important part of any general chemistry course, and students have difficulties understanding these concepts. The purpose of this research project is to examine some of the challenges and alternative conceptions that students face in learning about acid-base titrations. A Likert-type survey with open-ended questions were used to assess the understanding of 110 participants. The investigation took place at a public, urban, and minority-serving institute. Our data suggest that students struggle with learning about acid-base titration problems and concepts. They rely on algorithmic problem solving, rote- learning, plugging into equations, and calculator use when approaching acid-base titration problems instead of developing their conceptual understanding and meaningful learning of the concepts. Additionally, our data support the notion that development of conceptual understanding of acid-base titration is important for students' learning. Furthermore, our research data suggest that students have difficulties with understanding and visualizing what is taking place at the microscopic level during acid-base titration reactions. Instructors should consider teaching strategies that include leaning about and interrelating the symbolic, macroscopic, and microscopic levels of representations which can promote learning and deeper understanding of abstract chemical concepts. We recommend that instructors explicitly address and relate the three levels of representation in their teaching of chemistry concepts.
Keywords: chemistry education research, acid-base titration, challenge
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