5,698 research outputs found
Investigation Of Posttranscriptional Regulation After Global Brain Ischemia And Reperfusion Injury
The final cause of death in most patients revived after cardiac arrest is ischemia and reperfusion (I/R) injury in the brain. Survival after brain I/R injury depends on the expression of new stress response proteins such as heat shock protein 70 (HSP70). Little is known about why recovering neurons are able to express new stress response proteins while neurons that will die can transcribe RNA but do not translated protein in early reperfusion. Previous studies suggested that the mRNA-binding protein HuR may regulate hsp70 mRNA in reperfused neurons through a novel cytoplasmic structure, the mRNA granule. To determine the roles of HuR and the mRNA granule in reperfused neurons and to characterize global translation regulation, we 1) prevented mRNA granule formation in reperfused neurons or induced mRNA granules in uninjured neurons by pharmacological manipulation polysomes, 2. studied potential HuR posttranscriptional regulation mechanisms of facilitated nuclear export and polysome association, and 3. performed translation state analysis of reperfused neurons from hippocampal subregions CA1 and CA3.
We found that mRNA granules can be prevented in reperfused neurons by locking mRNA onto polysomes with cycloheximide. In uninjured neurons, mRNA granules can be induced with puromycin, which promotes early translation termination and dissociation of ribosomes from mRNA. In hippocampal neurons after 10 minutes global brain ischemia and 8 hours reperfusion, HuR remained constant in nuclear and cytoplasmic fractions and unfractionated homogenate. Nucleocytoplasmic distribution of hsp70 mRNA was identical between ischemia-resistant CA3 and ischemia-vulnerable CA1 neurons at 8 hours reperfusion. HuR\u27s distribution on polysome profiles was unchanged after 8 hours reperfusion, and HuR did not localize to polysomes in response to I/R injury. Translation state analysis of CA1 and CA3 neurons showed that the two regions have largely different mRNA populations on their polysomes at 8 hours reperfusion, and polysome-bound mRNA from both regions was enriched in the adenine and uridine rich element (ARE), a 3\u27 untranslated region regulatory site.
In conclusion, polysome-associated mRNA is necessary for mRNA granule formation. HuR may regulate expression of stress response proteins, but does not do so by any known mechanism. Ischemia-vulnerable CA1 and ischemia-resistant CA3 neurons have different mRNA populations associated with polysomes at 8 hours reperfusion after global ischemia, but both are enriched in AREs
Towards a Philosophy of Woodworking: Re-embracing Community and Quality Craftsmanship in Contemporary America
Since the Scientific Revolution of the seventeenth-century, humanity has appropriated the natural world for its uses, and only recently have we begun to understand the consequences of our actions. This misuse of the natural world has manifested itself thoroughly in all industries, including the woodworking field. To counteract this problem, I investigate its Cartesian philosophical underpinnings and propose a solution based upon the interconnected philosophy of the German Existentialist Martin Heidegger. Equipped with both the philosophy of Heidegger and concepts from the Deep Ecology movement (which insists upon the intrinsic value of all life on earth), I work to reformulate how woodworkers and tradesmen approach their craft. Before attempting this, however, I delve into a parallel field – that of organic agriculture – to investigate similarities in practical development. After a review of past woodworking philosophies, I develop six key concepts as well as a practical way forward for the woodworking community (based upon successes already witnessed in the organic movement). To conclude, I provide examples of how some aspects of this philosophy are already taking hold: most notably in vocational programs and small woodworking communities throughout our nation and the world
Invisible pushdown languages
Context free languages allow one to express data with hierarchical structure,
at the cost of losing some of the useful properties of languages recognized by
finite automata on words. However, it is possible to restore some of these
properties by making the structure of the tree visible, such as is done by
visibly pushdown languages, or finite automata on trees. In this paper, we show
that the structure given by such approaches remains invisible when it is read
by a finite automaton (on word). In particular, we show that separability with
a regular language is undecidable for visibly pushdown languages, just as it is
undecidable for general context free languages
Teaching multidisciplinary engineering using concepts and technology of WSN
This paper discusses teaching and learning strategies of Wireless Sensor Networks technology in a new postgraduate subject run at the Faculty of Engineering and IT, University of Technology, Sydney. The aim is to present the role of using practice based and multidisciplinary methodologies in the context of new ICT technologies. This includes shared experiences, observations and common problems experienced in teaching new concepts and paradigms, standards, protocols and algorithms, embedded systems and sensor technologies. The theory of WSN is applied as a driver of system development for the group projects that students undertake in the subject. © 2012 IEEE
Information coding with frequency of oscillations in Belousov-Zhabotinsky encapsulated disks
Information processing with an excitable chemical medium, like the Belousov-Zhabotinsky (BZ) reaction, is typically based on information coding in the presence or absence of excitation pulses. Here we present a new concept of Boolean coding that can be applied to an oscillatory medium. A medium represents the logical TRUE state if a selected region oscillates with a high frequency. If the frequency fails below a specified value, it represents the logical FALSE state. We consider a medium composed of disks encapsulating an oscillatory mixture of reagents, as related to our recent experiments with lipid-coated BZ droplets. We demonstrate that by using specific geometrical arrangements of disks containing the oscillatory medium one can perform logical operations on variables coded in oscillation frequency. Realizations of a chemical signal diode and of a single-bit memory with oscillatory disks are also discussed
Applications of cooperative WSN in homecare systems
Cooperation plays the crucial role in shared space of the homecare processes. It is a rather hard task to ensure effective cooperation in home care environment. This is due to variability of schedules, tasks and mobility of both patients and carers. In this paper, we discuss sensor network technology that can facilitate and improve home care cooperation scenarios. We present methodology, recommendations and applications for incorporating a WSN based solution in various areas of Homecare. We argue that even the most difficult areas of cooperation between patients and their carers such as: information retrieval, information dissemination, scheduling, coordination of short and long-term treatment can be supported by WSN based solutions. Finally, we discuss sensor network design approaches for incorporating smart communication devices and sensors to support health care workers and their patients in their daily activities. The network of smart sensors can help to maintain awareness of the activities of all stakeholders and the need to integrate communication and computer technology with the requirements of effective aged care infrastructure. © 2008 IEEE
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