2,981 research outputs found

    Multiway vortex valve system Patent

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    Multiple vortex amplifier system as fluid valv

    Single-node orbit analsyis with radiation heat transfer only

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    The steady-state temperature of a single node which dissipates energy by radiation only is discussed for a nontime varying thermal environment. Relationships are developed to illustrate how shields can be utilized to represent a louver system. A computer program is presented which can assess periodic temperature characteristics of a single node in a time varying thermal environment having energy dissipation by radiation only. The computer program performs thermal orbital analysis for five combinations of plate, shields, and louvers

    Role of Membrane GM1 on Early Neuronal Membrane Actions of Aβ During Onset of Alzheimer\u27s Disease

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    The ability of beta-amyloid peptide (Aβ) to disrupt the plasma membrane through formation of pores and membrane breakage has been previously described. However, the molecular determinants for these effects are largely unknown. In this study, we examined if the association and subsequent membrane perforation induced by Aβ was dependent on GM1levels. Pretreatment of hippocampal neurons with D-PDMP decreased GM1 and Aβ clustering at the membrane (Aβ fluorescent-punctas/20 μm, control = 16.2 ± 1.1 vs. D-PDMP = 6.4 ± 0.4, p \u3c 0.001). Interestingly, membrane perforation with Aβ occurred with a slower time course when the GM1 content was diminished (time to establish perforated configuration (TEPC) (min): control = 7.8 ± 2 vs. low GM1 = 12.1 ± 0.5, p \u3c 0.01), suggesting that the presence of GM1 in the membrane can modulate the distribution and the membrane perforation by Aβ. On the other hand, increasing GM1 facilitated the membrane perforation (TEPC: control = 7.8 ± 2 vs. GM1 = 6.2 ± 1 min, p \u3c 0.05). Additionally, using Cholera Toxin Subunit-B (CTB) to block the interaction of Aβ with GM1 attenuated membrane perforation significantly. Furthermore, pretreatment with CTB decreased the membrane association of Aβ (fluorescent-punctas/20 μm, Aβ: control = 14.8 ± 2.5 vs. CTB = 8 ± 1.4, p \u3c 0.05), suggesting that GM1 also plays a role in both association of Aβ with the membrane and in perforation. In addition, blockade of the Aβ association with CTB inhibited synaptotoxicity. Taken together, our results strongly suggest that membrane lipid composition can affect the ability of Aβ to associate and subsequently perforate the plasma membrane thereby modulating its neurotoxicity in hippocampal neurons

    Sizing-tube-fin space radiators

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    Temperature and size considerations of the tube fin space radiator were characterized by charts and equations. An approach of accurately assessing rejection capability commensurate with a phase A/B level output is reviewed. A computer program, based on Mackey's equations, is also presented which sizes the rejection area for a given thermal load. The program also handles the flow and thermal considerations of the film coefficient

    System analysis of a piston steam engine employing the uniflow principle, a study in optimized performance

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    Results are reported which were obtained from a mathematical model of a generalized piston steam engine configuration employing the uniflow principal. The model accounted for the effects of clearance volume, compression work, and release volume. A simple solution is presented which characterizes optimum performance of the steam engine, based on miles per gallon. Development of the mathematical model is presented. The relationship between efficiency and miles per gallon is developed. An approach to steam car analysis and design is presented which has purpose rather than lucky hopefulness. A practical engine design is proposed which correlates to the definition of the type engine used. This engine integrates several system components into the engine structure. All conclusions relate to the classical Rankine Cycle

    The Level of NMDA Receptor in the Membrane Modulates Amyloid-β Association and Perforation

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    Alzheimer’s disease is a neurodegenerative disorder that affects mostly the elderly. The main histopathological markers are the senile plaques formed by amyloid-β peptide (Aβ) aggregates that can perforate the plasma membrane of cells, increasing the intracellular calcium levels and releasing synaptic vesicles that finally lead to a delayed synaptic failure. Several membrane proteins and lipids interact with Aβ affecting its toxicity in neurons. Here, we focus on NMDA receptors (NMDARs) as proteins that could be modulating the association and neurotoxic perforation induced by Aβ on the plasma membrane. In fact, our results showed that decreasing NMDARs, using enzymatic or siRNA approaches, increased the association of Aβ to the neurons. Furthermore, overexpression of NMDARs also resulted in an enhanced association between NMDA and Aβ. Functionally, the reduction in membrane NMDARs augmented the process of membrane perforation. On the other hand, overexpressing NMDARs had a protective effect because Aβ was now unable to cause membrane perforation, suggesting a complex relationship between Aβ and NMDARs. Because previous studies have recognized that Aβ oligomers are able to increase membrane permeability and produce amyloid pores, the present study supports the conclusion that NMDARs play a critical protective role on Aβ actions in hippocampal neurons. These results could explain the lack of correlation between brain Aβ burden and clinically observed dementia

    Noncommutative Geometry of the Quantum Disk

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    We discuss various aspects of noncommutative geometry of a smooth subalgebra of the Toeplitz algebra. In particular, we study the structure of derivations on this subalgebra

    “46 YEARS REMOVED, 400 YEARS BEHIND: THE MISCONCEIVED EFFECTS OF INTEGRATION 2000 ON THE AFRICAN-AMERICAN COLLEGIATE”

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    “The university system, supposedly committed to diverse ideals and higher consciousness, has in reality become a white-centralized institution of exclusion.

    How Faculty and Students Understand and Experience the Development of Critical Thinking in the Online Classroom

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    Objectives: There are essentially three schools of thought regarding critical thinking—humanistic, cognitive, and behavioral. Given the disagreement among them, confusion continues about what critical thinking means, and how it can be taught to students. Methods: In this qualitative phenomenological study, researchers interviewed students and faculty in a distance education master of public health program about their perceptions and experiences of what critical thinking means and how it is developed in the online classroom. Results: Themes emerging from student interviews included (a) differing thoughts on the meaning of critical thinking; (b) learning and meeting course requirements as students’ primary role; (c) technology as useful in learning; and (d) confidence in learning linked to engagement, feedback, and course alignment. Themes from faculty interviews included (a) how online classrooms promoted critical thinking; (b) critical thinking identified when students demonstrate the application of independent thought; (c) facilitating and keeping students on track as faculty’s primary role; (d) promotion of critical thinking through questioning and student collaboration; (e) assessment of critical thinking through discussion posts; and (f) faculty facilitation and focus on application as essential to student learning. Conclusions: Students and faculty engaged in the online classroom agree in some ways that critical thinking skills are gained through practical applications. But this is where agreement ceases. Students believe they are developing critical thinking skills in their online environments, when in fact they are reproducing rote information in assignments. Implications: Engaging in activities has been shown to develop critical thinking more effectively when it is accompanied by mentoring, dialogue, and authentic instruction. Online educators who want to help students develop their critical thinking skills can use mentoring, dialogue, and authentic instruction alongside online activities

    Crossed Product C^*-algebras Associated With pp-adic Multiplication

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    We introduce and investigate some examples of C^*-algebras which are related to multiplication maps in the ring of pp-adic integers. We find ideals within these algebras and use the corresponding short exact sequences to compute the KK-Theory
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