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Search Results: 1 - 10 of 225493 matches for " Todd R. Gruninger "
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Sensory Perception of Food and Insulin-Like Signals Influence Seizure Susceptibility
Todd R. Gruninger,Daisy G. Gualberto,L. Rene Garcia
PLOS Genetics , 2008, DOI: 10.1371/journal.pgen.1000117
Abstract: Food deprivation is known to affect physiology and behavior. Changes that occur could be the result of the organism's monitoring of internal and external nutrient availability. In C. elegans, male mating is dependent on food availability; food-deprived males mate with lower efficiency compared to their well-fed counterparts, suggesting that the mating circuit is repressed in low-food environments. This behavioral response could be mediated by sensory neurons exposed to the environment or by internal metabolic cues. We demonstrated that food-deprivation negatively regulates sex-muscle excitability through the activity of chemosensory neurons and insulin-like signaling. Specifically, we found that the repressive effects of food deprivation on the mating circuit can be partially blocked by placing males on inedible food, E. coli that can be sensed but not eaten. We determined that the olfactory AWC neurons actively suppress sex-muscle excitability in response to food deprivation. In addition, we demonstrated that loss of insulin-like receptor (DAF-2) signaling in the sex muscles blocks the ability of food deprivation to suppress the mating circuit. During low-food conditions, we propose that increased activity by specific olfactory neurons (AWCs) leads to the release of neuroendocrine signals, including insulin-like ligands. Insulin-like receptor signaling in the sex muscles then reduces cell excitability via activation of downstream molecules, including PLC-γ and CaMKII.
Food Deprivation Attenuates Seizures through CaMKII and EAG K+ Channels
Brigitte LeBoeuf equal contributor,Todd R Gruninger equal contributor,L. Rene Garcia
PLOS Genetics , 2007, DOI: 10.1371/journal.pgen.0030156
Abstract: Accumulated research has demonstrated the beneficial effects of dietary restriction on extending lifespan and increasing cellular stress resistance. However, reducing nutrient intake has also been shown to direct animal behaviors toward food acquisition. Under food-limiting conditions, behavioral changes suggest that neuronal and muscle activities in circuits that are not involved in nutrient acquisition are down-regulated. These dietary-regulated mechanisms, if understood better, might provide an approach to compensate for defects in molecules that regulate cell excitability. We previously reported that a neuromuscular circuit used in Caenorhabditis elegans male mating behavior is attenuated under food-limiting conditions. During periods between matings, sex-specific muscles that control movements of the male's copulatory spicules are kept inactive by UNC-103 ether-a-go-go–related gene (ERG)–like K+ channels. Deletion of unc-103 causes ~30%–40% of virgin males to display sex-muscle seizures; however, when food is deprived from males, the incidence of spontaneous muscle contractions drops to 9%–11%. In this work, we used genetics and pharmacology to address the mechanisms that act parallel with UNC-103 to suppress muscle seizures in males that lack ERG-like K+ channel function. We identify calcium/calmodulin-dependent protein kinase II as a regulator that uses different mechanisms in food and nonfood conditions to compensate for reduced ERG-like K+ channel activity. We found that in food-deprived conditions, calcium/calmodulin-dependent protein kinase II acts cell-autonomously with ether-a-go-go K+ channels to inhibit spontaneous muscle contractions. Our work suggests that upregulating mechanisms used by food deprivation can suppress muscle seizures.
T. van Strien, K. van der Leer, A. Leerintveld, B. Bregman, Hofwijck. Het gedicht en de buitenplaats van Constantijn Huygens, Leerintveld, A., Bregman, B., ed.
R. Todd
BMGN : Low Countries Historical Review , 2003,
Potential confinement property in the Parabolic Anderson Model
Gabriela Gruninger,Wolfgang Konig
Mathematics , 2007,
Abstract: We consider the parabolic Anderson model, the Cauchy problem for the heat equation with random potential in $Z^d$. We use i.i.d. potentials $\xi: Z^d \to \R$ in the third universality class, namely the class of almost bounded potentials, in the classification of van der Hofstad, Konig and Morters [HKM06]. This class consists of potentials whose logarithmic moment generating function is regularly varying with parameter $\gamma=1$, but do not belong to the class of so-called double-exponentially distributed potentials studied by Gartner and Molchanov (PTRF 1998). In [HKM06] the asymptotics of the expected total mass was identified in terms of a variational problem that is closely connected to the well-known logarithmic Sobolev inequality and whose solution, unique up to spatial shifts, is a perfect parabola. In the present paper we show that those potentials whose shape (after appropriate vertical shifting and spatial rescaling) is away from that parabola contribute only negligibly to the total mass. The topology used is the strong $L^1$-topology on compacts for the exponentials of the potential. In the course of the proof, we show that any sequence of approximate minimisers of the above variational formula approaches some spatial shift of the minimiser, the parabola.
Validating New Technologies to Treat Depression, Pain and the Feeling of Sentient Beings: A Reply to “Neuroscience for the Soul”  [PDF]
Michael A. Persinger, Todd R. Murphy
Neuroscience & Medicine (NM) , 2016, DOI: 10.4236/nm.2016.71004
Abstract: The primary assumption of Neuroscience is that all experiences are strongly correlated with or caused by the specifics of brain structures and their particular dynamics. The profound experiences attributed to the “sensed presence” and their cultural anthropomorphisms such as deities and gods are persistent reports in human populations that are frequently associated with permanent changes in behavior, reduced depression and alleviation of pain. The majority of traditional clinical observations and modern imaging techniques have emphasized the central role of right temporal lobe structures and their directly related networks. The experimental simulation of sensed presences which can result in attributions to spiritual, deity-based or mystical sources within the clinical laboratory by the application of physiologically-patterned magnetic fields across the temporal lobes through our God Helmet requires the same precision of technology that is essential for synthesizing molecular treatments for modifying anomalous behavior, depression and pain. Despite the clinical utility of these simulated conditions within Neuroscience and Medicine, misinformation concerning the bases and efficacy of this new technology persist. Here we present detailed technical clarifications and rebuttals to refute these misconceptions. A Hegelian approach to this delay of development and impedance provides a context through which the ultimate synthesis and application of this technology may be accommodated in the near future.
Human genomic variation
Todd R Disotell
Genome Biology , 2000, DOI: 10.1186/gb-2000-1-5-comment2004
Abstract: On June 26, 2000 at the White House, Craig Venter, Celera Genomics' president and chief scientific officer, announced that the complete human genome had been assembled, using the whole-genome shotgun-sequencing method, in only nine months [1]. But what did he mean by 'the' human genome? In fact, the Celera research group sequenced a composite genome composed of three females and two males who identified themselves as African-American, Asian, Caucasian, and Hispanic. During his announcement, Venter explained that this sampling and the sequences generated from it, "help illustrate that the concept of race has no genetic or scientific basis." Numerous articles have appeared in the popular press since then with titles such as 'Do Races Differ? Not Really, Genes Show' [2]. Do Celera's data indeed demonstrate this?Celera's method of whole-genome shotgun sequencing allowed for the rapid discovery of hundreds of thousands of single nucleotide polymorphisms (SNPs). SNPs are less variable than microsatellite markers which have previously been widely used to characterize human molecular variation and evolution (see, for example, [3,4]), although they are also much more common and less mutationally complex [5,6]. In September 1998, the US National Center for Biotechnology Information (NCBI) created the Single Nucleotide Polymorphism database (dbSNP [7,8]) in order to gather widely disparate research groups' efforts into a common format that was readily accessible. Two years on, Celera launched its SNP database [9]. The first release of this database (September 2000) contains 2.4 million unique SNPs that are not found in the public databases [9]. So, taking these together with 400,000 non-redundant SNPs from the public databases, there now are over 2.8 million SNPs characterized throughout the human genome. Will this new resource tell us anything new about human variation?Prior to the SNP-gathering efforts, what was known about the patterns of human variation? Since the initial
'Chumanzee' evolution: the urge to diverge and merge
Todd R Disotell
Genome Biology , 2006, DOI: 10.1186/gb-2006-7-11-240
Abstract: The popular and scientific press gave extensive coverage to the recent analysis by Patterson et al. [1] of the human and chimpanzee genomes, in which they conclude that after initially splitting, our lineage continued to hybridize with chimpanzees for more than a million years. While the Washington Post noted that "Human ancestors may have interbred with chimpanzees" [2], Slate.com asked more bluntly: "Did humans mate with chimps? And are we their offspring?" [3].Given the extraordinary similarity of the chimpanzee and human genomes, scientists and the public alike have often asked such questions. An extensive review of the literature has yet to turn up a credible report of such crosses. In the 1920s, a Soviet scientist, Il'ya Ivanovich Ivanov, with the assistance of the Institut Pasteur at one of their field stations in French Guinea, unsuccessfully artificially inseminated three chimpanzees with human sperm [4]. He then tried to continue his experiments at the primate center at Sukhum in the then Soviet Republic of Georgia, where he intended to artificially inseminate human volunteers with ape sperm. He was arrested by the Soviet secret police on charges unrelated to this project and was never able to carry it out [4].Through their own sequencing efforts and data mining, Patterson et al. [1] have put together an alignment of human, chimpanzee, gorilla, orangutan, and macaque sequences that covers almost 20 Mb, which is 800 times larger than any previous analysis. But it is not just the size of the dataset that is important, it is the phylogenetic distribution. Most recent analyses of the human and chimpanzee genomes compare them with the mouse genome, which seems to be evolving at a different rate and under different constraints. By adding the very closely related gorilla, moderately close orangutan, and somewhat more distant macaque, the timing and processes of primate evolution can be more effectively studied. It is difficult, to nearly impossible, to infer whet
Discovering human history from stomach bacteria
Todd R Disotell
Genome Biology , 2003, DOI: 10.1186/gb-2003-4-5-213
Abstract: Charles Darwin recognized that the distribution and form of parasites was evolutionarily significant. He noted, for instance, that "... the Pediculi [lice] collected in different countries from the different races of man ... differ, not only in colour, but in the structure of their claws and limbs. In every case in which many specimens were obtained the differences were constant" [1]. More recently, several research groups [2-7] have found interesting correlations between the evolutionary relationships among various bacterial and viral strains hosted by humans and the pattern of migrations of modern humans throughout the world.A particularly interesting case is that of Helicobacter pylori, a Gram-negative bacterium associated with gastritis, peptic ulcers, and gastric cancer that may infect up to half of all humans [8]. The discovery that a bacterial infection could lead to what were considered chronic diseases [8] was a striking example of the fact that infectious diseases have not yet been conquered. The continuing acquired immune deficiency syndrome (AIDS) epidemic, outbreaks of Ebola in Central Africa, and the current spread of West Nile Virus in the United States and of severe acute respiratory syndrome (SARS) from Asia provide evidence of the pervasiveness and health consequences of infectious agents even in the age of vaccination and antimicrobial and antiviral therapies. Many infectious diseases are thought to have arisen concurrently with the development of agriculture and the rise of urban living. If, instead, many pathogens' relationships with humans are much older, it would not be surprising to find deeper evolutionary associations between humans and their microbial and viral invaders.The evolutionary history of H. pylori may provide an example of the coevolution of a bacterium and its only known host. The H. pylori genome is relatively small at 1.67 megabases, with a minimal complement of metabolic genes [9]. Variation between H. pylori isolates from di
Determining delay created by multifunctional prosthesis controllers
Todd R. Farrell, PhD
Journal of Rehabilitation Research and Development , 2011,
Abstract: I am writing to express a concern that my colleagues from previous laboratories at Northwestern University/Rehabilitation Institute of Chicago (RIC) and I have shared for a number of years related to multifunctional prosthesis control. Previous investigations have used a variety of analysis window attributes for their multifunctional prosthesis controllers [1-8]. Researchers have varied the length of the analysis window, the amount of overlap between consecutive windows, and the number of majority votes used in the postprocessing of the classifier decisions. However, we believe that many researchers have made decisions about these attributes with little regard for the overall delay created in the real-time system. (Note that the term classifier typically refers to an element of the controller that uses the inputs provided to it, e.g., electromyographic [EMG] signals, force sensor data, and position sensor data to decide which joint(s) of the prosthesis should be actuated.) For example, Peleg et al. performed classification decisions on data up to 1.4 seconds after the onset of the contraction [9]. This classifier would require its user to wait on the order of seconds for Peleg et al.'s prosthesis to respond, which would likely be quite frustrating for the user. We are not suggesting that new algorithms should not be explored simply because they may create substantial delays. However, we do believe that these delays should be considered and discussed in each article that is published on this topic. While a particular classifier may create a 1 percent increase in classification accuracy, if it cannot add this increase in accuracy in a reasonable amount of time, it may be a "nonstarter." Continuing in this vein, we would like to discuss some findings that we believe will allow prosthesis controller designers to better understand how their controllers will behave in real time. (For the purpose of this editorial, further use of "we" and "our" indicates my colleagues and me.)
Impact of Harvest Management on Forage Production and Nutrient Removal by Smooth Bromegrass on a Vegetated Treatment Area  [PDF]
R. Martine Similien, Todd P. Trooien, Jixiang Wu, Arvid Boe
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.69154
Abstract: Beef cattle (Bos taurus L.) feedlots pose serious environmental challenges associated with nutrient runoff. Smooth bromegrass (Bromus inermis Leyss.) is a perennial rhizomatous grass that is widely used for forage production in the USA and Canada. The objective of this research was to determine the best management system for producing forage from a vegetated treatment area (VTA) while maintaining the capacity of the VTA to remove nutrients from feedlot effluent. Four harvest management treatments (1-, 2-, and 3-harvest per year and an un-harvested control) were applied during spring 2005 and evaluated over a 5-yr period in a smooth brome sward on a VTA near Howard, SD. Mean annual total forage production during a 4-yr period ranged from 6.2 Mg·ha-1 to 9.5 Mg·ha-1 for 1- and 3-harvest systems, respectively. Nutrient removal by the bromegrass ranged from 148 kg·N·ha-1 and 15 kg·P·ha-1 for the 1-harvest treatment to 244 kg·ha-1 N and 24 kg·ha-1 P for the 3-harvest treatment. Results indicated that high amounts of smooth bromegrass forage could be produced and soil nutrients removed from 2- and 3-harvest systems without compro-mising stand vigor and persistence on a VTA in eastern South Dakota.
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