2,698 research outputs found
Analysis of Automotive Cyber-Attacks on Highways using Partial Differential Equation Models
This is the author accepted manuscript.This paper considers scenarios wherein a group of
malicious vehicles on a highway perform a cooperative attack
with the motive of creating undesirable wave effects among other
vehicles on the highway. The two species of vehicles - malicious
vehicles and normal vehicles, and their associated interaction
effects, are modeled using Partial Differential Equations (PDEs).
The malicious vehicles, which may be arbitrarily distributed on
the highway, perform a sequence of velocity changes with the
objective of making the density/velocity profile on the highway,
track a reference profile. This reference profile (chosen by the
malicious vehicles) has the property that once generated, it
spontaneously evolves into a shock wave that propagates along
the highway. Analytical expressions governing the velocity inputs
of the malicious vehicles with which they can generate such waves
are determined, for perfect as well as imperfect information
scenarios. Simulation results are presented to validate the theoryThe first two authors would like to acknowledge support from the National Science Foundation. This material is based upon work supported by the National Science Foundation under Grant IIS-1351677
Pathways to clinical CLARITY: volumetric analysis of irregular, soft, and heterogeneous tissues in development and disease
AbstractThree-dimensional tissue-structural relationships are not well captured by typical thin-section histology, posing challenges for the study of tissue physiology and pathology. Moreover, while recent progress has been made with intact methods for clearing, labeling, and imaging whole organs such as the mature brain, these approaches are generally unsuitable for soft, irregular, and heterogeneous tissues that account for the vast majority of clinical samples and biopsies. Here we develop a biphasic hydrogel methodology, which along with automated analysis, provides for high-throughput quantitative volumetric interrogation of spatially-irregular and friable tissue structures. We validate and apply this approach in the examination of a variety of developing and diseased tissues, with specific focus on the dynamics of normal and pathological pancreatic innervation and development, including in clinical samples. Quantitative advantages of the intact-tissue approach were demonstrated compared to conventional thin-section histology, pointing to broad applications in both research and clinical settings.</jats:p
Consistent Anisotropic Repulsions for Simple Molecules
We extract atom-atom potentials from the effective spherical potentials that
suc cessfully model Hugoniot experiments on molecular fluids, e.g., and
. In the case of the resulting potentials compare very well with the
atom-atom potentials used in studies of solid-state propertie s, while for
they are considerably softer at short distances. Ground state (T=0K) and
room temperatu re calculations performed with the new potential resolve
the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure
Motor symptoms in Parkinson's disease: A unified framework
Parkinson’s disease (PD) is characterized by a range of motor symptoms. Besides the cardinal symptoms (akinesia and bradykinesia, tremor and rigidity), PD patients show additional motor deficits, including: gait disturbance, impaired handwriting, grip force and speech deficits, among others. Some of these motor symptoms (e.g., deficits of gait, speech, and handwriting) have similar clinical profiles, neural substrates, and respond similarly to dopaminergic medication and deep brain stimulation (DBS). Here, we provide an extensive review of the clinical characteristics and neural substrates of each of these motor symptoms, to highlight precisely how PD and its medical and surgical treatments impact motor symptoms. In conclusion, we offer a unified framework for understanding the range of motor symptoms in PD. We argue that various motor symptoms in PD reflect dysfunction of neural structures responsible for action selection, motor sequencing, and coordination and execution of movement
Brain fatty acid synthase activates PPARa to maintain energy homeostasis
Central nervous system control of energy balance affects susceptibility to obesity and diabetes, but how fatty acids, malonyl-CoA, and other metabolites act at this site to alter metabolism is poorly understood. Pharmacological inhibition of fatty acid synthase (FAS), rate limiting for de novo lipogenesis, decreases appetite independently of leptin but also promotes weight loss through activities unrelated to FAS inhibition. Here we report that the conditional genetic inactivation of FAS in pancreatic β cells and hypothalamus produced lean, hypophagic mice with increased physical activity and impaired hypothalamic PPARα signaling. Administration of a PPARα agonist into the hypothalamus increased PPARα target genes and normalized food intake. Inactivation of β cell FAS enzyme activity had no effect on islet function in culture or in vivo. These results suggest a critical role for brain FAS in the regulation of not only feeding, but also physical activity, effects that appear to be mediated through the provision of ligands generated by FAS to PPARα. Thus, 2 diametrically opposed proteins, FAS (induced by feeding) and PPARα (induced by starvation), unexpectedly form an integrative sensory module in the central nervous system to orchestrate energy balance
Retrieval effectiveness of written and spoken queries : an experimental evaluation
With the fast growing speech technologies, the world is emerging to a new speech era. Speech recognition has now become a practical technology for real world applications. While some work has been done to facilitate retrieving information in speech format using textual queries, the characteristics of speech as a way to express an information need has not been extensively studied. If one compares written versus spoken queries, it is intuitive to think that users would issue longer spoken queries than written ones, due to the ease of speech. Is this in fact the case in reality? Also, if this is the case, would longer spoken queries be more effective in helping retrieving relevant document than written ones? This paper presents some new findings derived from an experimental study to test these intuitions
HSPB1 facilitates ERK-mediated phosphorylation and degradation of BIM to attenuate endoplasmic reticulum stress-induced apoptosis
BIM, a pro-apoptotic BH3-only protein, is a key regulator of the intrinsic (or mitochondrial) apoptosis pathway. Here, we show that BIM induction by endoplasmic reticulum (ER) stress is suppressed in rat PC12 cells overexpressing heat shock protein B1 (HSPB1 or HSP27) and that this is due to enhanced proteasomal degradation of BIM. HSPB1 and BIM form a complex that immunoprecipitates with p-ERK1/2. We found that HSPB1-mediated proteasomal degradation of BIM is dependent on MEK-ERK signaling. Other studies have shown that several missense mutations in HSPB1 cause the peripheral neuropathy, Charcot-Marie-Tooth (CMT) disease, which is associated with nerve degeneration. Here we show that cells overexpressing CMT-related HSPB1 mutants exhibited increased susceptibility to ER stress-induced cell death and high levels of BIM. These findings identify a novel function for HSPB1 as a negative regulator of BIM protein stability leading to protection against ER stress-induced apoptosis, a function that is absent in CMT-associated HSPB1 mutants
Answering SPARQL queries over databases under OWL 2 QL entailment regime
We present an extension of the ontology-based data access platform Ontop that supports answering SPARQL queries under the OWL 2 QL direct semantics entailment regime for data instances stored in relational databases. On the theoretical side, we show how any input SPARQL query, OWL 2 QL ontology and R2RML mappings can be rewritten to an equivalent SQL query solely over the data. On the practical side, we present initial experimental results demonstrating that by applying the Ontop technologies—the tree-witness query rewriting, T-mappings compiling R2RML mappings with ontology hierarchies, and T-mapping optimisations using SQL expressivity and database integrity
constraints—the system produces scalable SQL queries
MicroRNAs in pulmonary arterial remodeling
Pulmonary arterial remodeling is a presently irreversible pathologic hallmark of pulmonary arterial hypertension (PAH). This complex disease involves pathogenic dysregulation of all cell types within the small pulmonary arteries contributing to vascular remodeling leading to intimal lesions, resulting in elevated pulmonary vascular resistance and right heart dysfunction. Mutations within the bone morphogenetic protein receptor 2 gene, leading to dysregulated proliferation of pulmonary artery smooth muscle cells, have been identified as being responsible for heritable PAH. Indeed, the disease is characterized by excessive cellular proliferation and resistance to apoptosis of smooth muscle and endothelial cells. Significant gene dysregulation at the transcriptional and signaling level has been identified. MicroRNAs are small non-coding RNA molecules that negatively regulate gene expression and have the ability to target numerous genes, therefore potentially controlling a host of gene regulatory and signaling pathways. The major role of miRNAs in pulmonary arterial remodeling is still relatively unknown although research data is emerging apace. Modulation of miRNAs represents a possible therapeutic target for altering the remodeling phenotype in the pulmonary vasculature. This review will focus on the role of miRNAs in regulating smooth muscle and endothelial cell phenotypes and their influence on pulmonary remodeling in the setting of PAH
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