Baccelli E.,French Institute for Research in Computer Science and Automation |
Philipp M.,French Institute for Research in Computer Science and Automation |
2011 International Conference on Software, Telecommunications and Computer Networks, SoftCOM 2011 | Year: 2011
An important part of the foreseen Internet of Things consists in wireless sensor networks running adapted IPv6 protocols. Since the way sensors are scattered is generally unplanned and may evolve with time, a routing protocol is needed in order to provide paths across such networks. Efforts towards standardizing RPL, a routing protocol targeting sensor networks, have thus recently taken place. This paper analyzes some fundamental tradeoffs inherent to RPL, which enables the protocol to require smaller routing state than most other routing protocols. However, these tradeoffs are on the other hand an issue in several Home and Building Automation use-cases, which require sensor to sensor communication - aside of communication from sensor to sink. RPL basically requires that all communication paths go through a central router (the sink), which provides severely suboptimal paths in these use-cases. In order to alleviate this, an extension of the protocol is proposed based on a reactive scheme that can provide shorter paths on-demand, without necessarily going through the sink. This paper then evaluates this extension via experiments on a sensor network testbed running RPL and its extension over IEEE 802.15.4 radio. These experiments confirm that the extension provides substantially shorter paths. © 2011 University of Split.
A study published recently by Edward (Ned) Ruby, professor at the University of Hawai'i - Mānoa's Pacific Biosciences Research Center (PBRC) and colleagues from the University of Wisconsin - Madison (UWM) revealed that Vibrio fischeri has a novel type of receptors that sense the presence and concentration of fatty acids, a building block of all cell membranes. This class of receptors allows a bacterium to migrate toward short-chain fatty acids- a phenomenon referred to as chemotaxis. "This is the first example of a receptor for this class of compounds, and this receptor appears to have evolved in, and be restricted to, the Vibrionaceae family of marine bacteria," said Ruby. Sending and receiving chemical signals allow bacteria to communicate with other organisms, gather information about their environment, and determine with whom to create a mutually beneficial partnership - a symbiosis. For example, the Hawaiian bobtail squid hatchlings aren't born with Vibrio fischeri. They attract it, and only it, from the surrounding seawater using chemoattractants, and capture it in their light organs. However, the newly discovered fatty-acid sensors are not required for the bacterium to initiate symbiosis with the squid. Thus, the ability to migrate towards fatty acids appears to play a critical role in some other aspect of the bacterium's life history. "Interestingly, in Vibrio fischeri the gene encoding the receptor has duplicated, so that the cell has two copies of similar, and apparently functionally identical, genes. Such genetic investment in this receptor suggests that the ability to sense and migrate toward fatty acids may be important in the pathogenicity of other Vibrio species like Vibrio cholera [which causes cholera], Vibrio vulnificus [which causes necrotizing skin infections and gastroenteritis] and others," said Ruby. All organisms, even humans, use chemotaxis to attract beneficial microbes to specific tissues. For example, as human infants are exposed to bacteria in their environment, they must attract desirable species to particular tissues - gut, skin, teeth, reproductive tract - that must be colonized by these bacteria. In the future, Ruby and colleagues will continue to try and discover the attractants that allow Vibrio fischeri to be the only bacterial species that can colonize the light organ of the squid. With only one species to track, it is easier to study the colonization process than when there are dozens or hundreds of bacterial species that are needed to colonize the tissue (like the gut). Understanding how this colonization takes place will lead to greater understanding of how Earth's many microbiomes become constructed and, thus allow us to better construct and manage them. Explore further: Single gene lets bacteria jump from host to host
"I intentionally heat up an object a little bit, and it wants to expand because it's heating up, so it generates an outgoing pressure pulse. We measure those pressure pulses with ultrasound receivers," Patch explained. "A few years ago, we landed a grant through UWM's instrumentation award program to purchase a research-friendly ultrasound system. Now I can use a transducer just like those in hospitals to 'listen' for the signal." Patch uses that existing technology to create 3D images of prostates with the goal of crafting a diagnostic tool that spots cancer without the risks associated with biopsies. She started by imaging cancerous prostates immediately after they were removed from patients at Froedtert & the Medical College of Wisconsin. "Lots of folks at MCW have been very supportive of this project, from Dr. (William) See in urology, to the MCW Tissue Bank and MCW's Clinical & Translational Science Institute," Patch said. To create thermoacoustic images, Patch needed a way to heat prostates uniformly. In the basement of the UWM Physics building, a souped-up FM radio transmitter propagates high-power VHF (very high frequency) pulses through her bench-top imaging system. The signal is driven by electrical conductivity. Healthy prostate glands produce fluid that is about three times more conductive than blood or plasma. Unhealthy prostate glands produce less conductive fluid. Patch and collaborator Dr. David Hull compare the thermoacoustic images to the corresponding prostate samples to determine whether the images could be used for cancer diagnosis. If thermoacoustic imaging proves as effective as more costly techniques, Patch would look to image prostates still inside patients. The process would be similar to the current transrectal biopsy now used for diagnosing tumors. "We are looking for surgeons in town to help us move to the next level," she said. "To drum up funds to build a prototype, we'll need to have physicians and patients on board who will allow us to perform thermoacoustic imaging the biopsy procedure." Longer term, she hopes to image other abdominal organs, like the liver and pancreas. It's also possible that thermoacoustic imaging could do more than just detect cancer; it could be used to treat it. Proton therapy is a method of cancer treatment in which doctors direct a beam of charged particles at a tumor. Unlike regular radiation treatments, in which X-rays can affect a wide area of the body, particle beams deposit most of their energy at a certain point known as the Bragg peak, and then die away almost completely. In principle, treatment can be focused on the tumor, leaving the healthy tissue beyond the Bragg peak untouched. Positioning errors, however, result in treating healthy tissue and under-treating the tumor. Patch and scientists working on the Lawrence Berkeley National Lab's (LBNL) 88-inch cyclotron worked together to detect thermoacoustic emissions from the Bragg peak. Patch tested her newest ultrasound equipment at Berkeley last summer with an upgraded cyclotron that accelerates protons to approximately one-third the speed of light. "LBNL donated a day's worth of time of on the cyclotron. We did some experiments and it worked better than I thought it would," Patch said. LBNL also provided staff support, including technicians who modified electronics, operators who controlled the beam and a scientist coaxed out of retirement. The experiment involved pulsing a proton beam at a "phantom," a model of human tissue used for ultrasound. The team designed a phantom with a cavity that mimicked a portion of the intestine, because gas pockets wreak havoc with treatment plans. Scientists George Noid and Allen Li at MCW took CT scans of the phantom, which Patch used to estimate the Bragg peak when the cavity was empty and when it was filled with olive oil. "The beam could penetrate 2 centimeters in the oil. But when the cavity is empty, the beam flies right through and doesn't slow down until it enters phantom material. With my ultrasound transducers, we can see that difference pretty accurately," Patch said. Her results are preliminary, but Patch thinks that if the team continues to see positive results, thermoacoustics could improve the accuracy of proton therapy.
Imagine engines that conserve fuel by automatically dialing down internal friction, water pipes that seal their own cracks and iPhones that protect themselves when dropped. Metallurgist Pradeep Rohatgi has—and he invented the futuristic materials necessary to build these smart products. For 40 years, Rohatgi has been steadily creating metal matrix composites, which combine standard metal alloys with completely different classes of material—ceramics, nanoparticles and even recycled waste—to give them “smart” qualities. For all their potential, most of Rohatgi’s creations sat on the shelf for decades. But a flourishing entrepreneurial culture at UW-Milwaukee, the right partners and a national push for conservation and energy independence convinced him to make the leap into the commercial sphere. He’s doing so with a product line made using a self-lubricating composite, one he believes will cut friction in internal combustion engines significantly, saving gas while reducing emissions. “The federal mandates to reduce carbon emissions and increase fuel efficiency could be the incentives that finally help these composites into the marketplace,” said engineering alumnus Chris Jordan, who worked in Rohatgi’s lab as an undergraduate. Jordan and lab mate Simon Beno have joined Rohatgi and two of his collaborators in a startup company, Intelligent Composites, which aims to get car parts made with the composite into commercial use. If successful, the startup’s product line could reinvigorate Wisconsin foundries that have lost business to cheap labor overseas. Rohatgi pioneered the development of metal matrix composites in the 1970s while working for the International Nickel Company’s U.S. lab. An official at General Motors suggested the lab develop a lightweight alternative to cast iron that would reduce the weight of vehicles and reduce the cost of shipping vehicles to showrooms. But metal matrix composites were high-tech materials too complicated to mass-produce, and automakers balked at the cost, Rohatgi recalled. At the time, gas was cheap, so there was little motivation for them to pursue the research. Rohatgi, however, persevered, believing the materials could improve lives and provide jobs. “These composites can give old-line manufacturing the means to produce new, high-tech products that industries can’t find anywhere else,” he said. Rohatgi and longtime collaborator David Weiss spent years testing composites with various smart qualities at Manitowoc’s Eck Industries, where Weiss is vice president of engineering. They resolved compatibility issues and devised a method to mass-produce composites in foundries, bringing down the cost. Metal matrix composites have been the exclusive property of labs that custom-make them for use in projects like the Hubble spacecraft. Now, Eck will prove that same technology can be used to produce the engine part Intelligent Composites will sell. “For years, Pradeep used to come to Eck, and we were trying to understand how we could scale up some of his inventions with the goal always of bringing them to the commercial market,” said Weiss, who is also acting CEO for Intelligent Composites. “What was missing was a business that could take the materials into production and sell them.” Jordan was already a successful Internet entrepreneur when he returned to college to finish his bachelor’s degree. He took a part-time job in Rohatgi’s lab in 2012, just as the professor decided to enter the self-lubricating composite in the Governor’s Business Plan competition. “He said it was only an academic exercise when he asked me to get involved,” Jordan said. But within a week, Jordan was envisioning a profitable startup. He sought help from James Hunter, a Lubar School of Business entrepreneur-in-residence who signed on as the startup’s chief financial officer. Promising early test results helped Intelligent Composites attract more than $350,000 in grant funding during its first 15 months. According to the team’s market research, engine and vehicle manufacturers facing stricter federal emissions regulations would sit up and take notice if presented with a cost-competitive method of reducing fuel consumption and emissions by 1 or 2 percent. Prototypes of a rotary engine with a part made from self-lubricating composite have produced far better results. Independent testing reported a 35 percent reduction in fuel consumption compared to rotary engines made of traditional materials. Jordan and Beno hope to see similar benefits when the composite reduces friction between pistons and cylinders in internal combustion engines. Piston engines are used in almost all cars and trucks, so the impact could be dramatic. “If every car and truck in the country used Intelligent Composites cylinder liners, the United States could become energy independent,” Beno said. His claim is supported by years of testing Rohatgi and Weiss did with manufacturing giants Ford, Briggs & Stratton and Oshkosh Corp. before Intelligent Composites formed. Robert Hathaway, a UW-Milwaukee alumnus and vice president of Global Technology—Materials and Process Engineering at Oshkosh Corp., has collaborated on research projects with Rohatgi for two decades. “We believe these materials have commercial merit,” Hathaway wrote in a letter supporting the startup’s application for a Small Business Technology Transfer grant. “Should Intelligent Composites achieve the goals outlined in the federal grant application, Oshkosh Corporation would be interested in giving this technology a closer look.” Although much more testing is ahead, the team also is executing a two-pronged game plan to break into the market. Weiss is introducing the composite parts to original equipment manufacturers, or OEMs. These companies, like the major automakers, outsource production of parts used in their final product and can influence others. “These are disruptive materials that call for the suppliers to change manufacturing processes,” Weiss said. “And manufacturers are not as accepting of change as some of the high-tech companies are.” Growth potential may help nudge them, Rohatgi said. There are at least 25 other vehicle parts that could become more energy-efficient if made with the composite. Jordan and Beno are focusing on a second front. They plan to make and sell engine cylinder liners for power sport vehicles—ATVs, snowmobiles and watercraft. “We first want to approach a group that could be early adopters,” Weiss said. “Racers are willing to do anything quickly that will give them a competitive advantage. Winning over power sport vehicle users would help validate the technology and show other OEMs that customers want to see Intelligent Composites components in their vehicles, Jordan said. Grateful for the university’s support, the Intelligent Composites team granted 1 percent equity in the startup to the UWM Research Foundation. “I feel like the university environment allowed this work to grow,” Rohatgi said. “Our partnership holds an important tech-transfer lesson on the critical role of testing great academic ideas in the industry environment. Each one helps propel and hone the other.”
Bauer D.J.,UWM |
Bauer D.J.,Viterbo University |
Peterson T.C.,UWM |
Peterson T.C.,Southern Illinois University Carbondale |
Brain Research | Year: 2014
Anatomical tracing studies in primates have revealed neural tracts from the cerebellar dentate nuclei to prefrontal cortex, implicating a cerebellar role in nonmotor processes. Experiments in rats examining the functional role of this cerebellothalamocortical pathway have demonstrated the development of visuospatial and motivational deficits following lesions of the dentate nuclei, in the absence of motor impairment. These behavioral deficits possibly occur due to structural modifications of the cerebral cortex secondary to loss of cerebellar input. The current study characterized morphological alterations in prefrontal cortex important for visuospatial and motivational processes following bilateral cerebellar dentate nuclei lesions. Rats received either bilateral electrolytic cerebellar dentate nuclei lesions or sham surgery followed by a 30-day recovery. Randomly selected Golgi-impregnated neurons in prefrontal cortex were examined for analysis. Measures of branch length and spine density revealed no differences between lesioned and sham rats in either apical or basilar arbors; however, the proportion of immature to mature spines significantly decreased in lesioned rats as compared to sham controls, with reductions of 33% in the basilar arbor and 28% in the apical arbor. Although expected pruning of branches and spines did not occur, the results are consistent with the hypothesis that cerebellar lesions influence prefrontal morphology and support the possibility that functional deficits following cerebellar dentate nuclei lesions are related to prefrontal morphological alteration. © 2013 Elsevier B.V. All rights reserved.