743 research outputs found
Descriptive Linear modeling of steady-state visual evoked response
A study is being conducted to explore use of the steady state visual-evoke electrocortical response as an indicator of cognitive task loading. Application of linear descriptive modeling to steady state Visual Evoked Response (VER) data is summarized. Two aspects of linear modeling are reviewed: (1) unwrapping the phase-shift portion of the frequency response, and (2) parsimonious characterization of task-loading effects in terms of changes in model parameters. Model-based phase unwrapping appears to be most reliable in applications, such as manual control, where theoretical models are available. Linear descriptive modeling of the VER has not yet been shown to provide consistent and readily interpretable results
On the hygrothermomechanical characterization of polyvinyl acetate
As a part of a program to understand the mechanisms of failure in time-dependent adhesion and film bonding, the creep compliance of polyvinyl acetate (PVAc) in shear has been determined both as a function of temperature and absorbed moisture. Volumetric expansion as a function of temperature or moisture takeup was also measured. We find that practically realizable changes in moisture content affect both the creep compliance and the swelling of PVAc to a degree comparable to that resulting from realistic changes in temperature. For example, the creep rates (histories) at corresponding times for PVAc subjected to 92% relative humidity storage are accelerated by approximately four orders of magnitude over those found for the dry material. Moreover, we find within reasonable experimental error that water concentration affects the time scale of creep like temperature through a concentration-dependent shift factor. An attempt is made at discussing the interrelation of temperature- and moisture-induced volume changes
A Transgenic Rat for Investigating the Anatomy and Function of Corticotrophin Releasing Factor Circuits.
Corticotrophin-releasing factor (CRF) is a 41 amino acid neuropeptide that coordinates adaptive responses to stress. CRF projections from neurons in the central nucleus of the amygdala (CeA) to the brainstem are of particular interest for their role in motivated behavior. To directly examine the anatomy and function of CRF neurons, we generated a BAC transgenic Crh-Cre rat in which bacterial Cre recombinase is expressed from the Crh promoter. Using Cre-dependent reporters, we found that Cre expressing neurons in these rats are immunoreactive for CRF and are clustered in the lateral CeA (CeL) and the oval nucleus of the BNST. We detected major projections from CeA CRF neurons to parabrachial nuclei and the locus coeruleus, dorsal and ventral BNST, and more minor projections to lateral portions of the substantia nigra, ventral tegmental area, and lateral hypothalamus. Optogenetic stimulation of CeA CRF neurons evoked GABA-ergic responses in 11% of non-CRF neurons in the medial CeA (CeM) and 44% of non-CRF neurons in the CeL. Chemogenetic stimulation of CeA CRF neurons induced Fos in a similar proportion of non-CRF CeM neurons but a smaller proportion of non-CRF CeL neurons. The CRF1 receptor antagonist R121919 reduced this Fos induction by two-thirds in these regions. These results indicate that CeL CRF neurons provide both local inhibitory GABA and excitatory CRF signals to other CeA neurons, and demonstrate the value of the Crh-Cre rat as a tool for studying circuit function and physiology of CRF neurons
Optical Fiber Distributed Sensing Structural Health Monitoring (SHM) Strain Measurements Taken During Cryotank Y-Joint Test Article Load Cycling at Liquid Helium Temperatures
This paper outlines cryogenic Y-joint testing at Langley Research Center (LaRC) to validate the performance of optical fiber Bragg grating strain sensors for measuring strain at liquid helium temperature (-240 C). This testing also verified survivability of fiber sensors after experiencing 10 thermal cool-down, warm-up cycles and 400 limit load cycles. Graphite composite skins bonded to a honeycomb substrate in a sandwich configuration comprised the Y-joint specimens. To enable SHM of composite cryotanks for consideration to future spacecraft, a light-weight, durable monitoring technology is needed. The fiber optic distributed Bragg grating strain sensing system developed at LaRC is a viable substitute for conventional strain gauges which are not practical for SHM. This distributed sensing technology uses an Optical Frequency Domain Reflectometer (OFDR). This measurement approach has the advantage that it can measure hundreds of Bragg grating sensors per fiber and the sensors are all written at one frequency, greatly simplifying fiber manufacturing. Fiber optic strain measurements compared well to conventional strain gauge measurements obtained during these tests. These results demonstrated a high potential for a successful implementation of a SHM system incorporating LaRC's fiber optic sensing system on the composite cryotank and other future cryogenic applications
Phencyclidine (PCP)-like discriminative stimulus effects of metaphit and of 2-amino-5-phosphonovalerate in pigeons: generality across different training doses of PCP
Pigeons were trained to discriminate either a fixed dose of PCP (1 mg/kg; n =3) or a progressively decreasing dose (1-0.56–0.32 mg/kg; n =4) from saline. Lowering of the training dose shifted the dose-effect curve for PCP's discriminative stimulus effects about 5-fold to the left, in a parallel manner, but did not decrease the accuracy of the discrimination performance and did not significantly increase the extent to which pentobarbital and chlordiazepoxide produced PCP-appropriate responding. Dose-effect curves based on binary generalization data were evaluated statistically with new methods that may be more appropriate than those used previously. Metaphit, a proposed PCP-receptor acylator, and 2-amino-5-phosphonovalerate (AP5), an N-methyl- d -aspartate (NMDA) antagonist, produced complete PCP-appropriate responding in the high training dose group only at doses that suppressed the rate of responding and that produced ataxia. However, 4-fold lower doses of metaphit and AP5, which did not produce directly observable behavioral effects, were found to substitute completely for PCP in the low training dose group. These data support the notion that PCP, metaphit, and AP5 have a common discriminative effect in pigeons.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46447/1/213_2004_Article_BF00207232.pd
Proteomic Analysis Identifies NDUFS1 and ATP5O as Novel Markers for Survival Outcome in Prostate Cancer
Simple Summary Due to the heterogeneity of prostate cancer (PCa), it is still difficult to provide risk stratification. Metabolic changes in PCa tissue have been described during tumor progression at genetic and transcriptomic level, but these have not yet clearly contributed to improved diagnosis and therapy. The aim of our study was to identify novel markers for aggressive prostate cancer in a proteomics-derived dataset by immunohistochemical analysis and correlation with transcriptomic data. Here, we provide potential new markers-NDUFS1 and ATP5O-for risk stratification in PCa. Additionally, we reveal for the first time a concordant increase of NDUFS1/ATP5O of mRNA expression in transcriptomic datasets and at protein level. We aimed to identify novel markers for aggressive prostate cancer in a STAT3-low proteomics-derived dataset of mitochondrial proteins by immunohistochemical analysis and correlation with transcriptomic data and biochemical recurrence in a STAT3 independent PCa cohort. Formalin-fixed paraffin-embedded tissue (FFPE) sample selection for proteomic analysis and tissue-microarray (TMA) generation was conducted from a cohort of PCa patients. Retrospective data analysis was performed with the same cohort. 153 proteins differentially expressed between STAT3-low and STAT3-high samples were identified. Out of these, 46 proteins were associated with mitochondrial processes including oxidative phosphorylation (OXPHOS), and 45 proteins were upregulated, including NDUFS1/ATP5O. In a STAT3 independent PCa cohort, high expression of NDUFS1/ATP5O was confirmed by immunocytochemistry (IHC) and was significantly associated with earlier biochemical recurrence (BCR). mRNA expression levels for these two genes were significantly higher in intra-epithelial neoplasia and in PCa compared to benign prostate glands. NDUFS1/ATP5O levels are increased both at the mRNA and protein level in aggressive PCa. Our results provide evidence that NDUFS1/ATP5O could be used to identify high-risk PCa patients
Long Term Displacement Data of Woven Fabric Webbings Under Constant Load for Inflatable Structures
Inflatable modules for space applications offer weight and launch volume savings relative to current metallic modules. Limited data exist on the creep behavior of the restraint layer of inflatable modules. Long-term displacement and strain data of two high strength woven fabric webbings, Kevlar and Vectran, under constant load is presented. The creep behavior of webbings is required by designers to help determine service life parameters of inflatable modules. Four groups of different webbings with different loads were defined for this study. Group 1 consisted of 4K Kevlar webbings loaded to 33% ultimate tensile strength and 6K Vectran webbings loaded to 27% ultimate tensile strength, group 2 consisted of 6K Kevlar webbings loaded to 40% and 43% ultimate tensile strength, and 6K Vectran webbings loaded to 50% ultimate tensile strength, group 3 consisted of 6K Kevlar webbings loaded to 52% ultimate tensile strength and 6K Vectran webbings loaded to 60% ultimate tensile strength, and group 4 consisted of 12.5K Kevlar webbings loaded to 22% ultimate tensile strength, and 12.5K Vectran webbings loaded to 22% ultimate tensile strength. The uniquely designed test facility, hardware, displacement measuring devices, and test data are presented. Test data indicate that immediately after loading all webbings stretch an inch or more, however as time increases displacement values significantly decrease to fall within a range of several hundredth of an inch over the remainder of test period. Webbings in group 1 exhibit near constant displacements and strains over a 17-month period. Data acquisition was suspended after the 17th month, however webbings continue to sustain load without any local webbing damage as of the 21st month of testing. Webbings in group 2 exhibit a combination of initial constant displacement and subsequent increases in displacement rates over a 16-month period. Webbings in group 3 exhibit steady increases in displacement rates leading to webbing failure over a 3-month period. Five of six webbings experienced local damage and subsequent failure in group 3. Data from group 4 indicates increasing webbing displacements over a 7-month period. All webbings in groups 1, 2, and 4 remain suspended without any local damage as of the writing of this paper. Variations in facility temperatures over test period seem to have had limited effect on long-term webbing displacement data
Connecting children’s worlds: Creating a multilingual syncretic curriculum through partnership between complementary and mainstream schools
Children from minority-language backgrounds have multiple sites of learning: home, community, mainstream school, and in some cases complementary school where they study their mother tongue after school or at weekends. However, due to the institutional constraints of an education system based on monolingual principles, mainstream teachers are often unaware of the contribution that complementary classes make to children’s learning, or unsure of how to draw on their pupils’ linguistic knowledge in the curriculum. Children’s multilingual identities and their other worlds of learning therefore remain invisible in mainstream school. This paper describes an action research study with teachers from complementary and mainstream schools in East London, in which they jointly planned lessons around topics that were then taught in both settings. The complementary teachers brought a holistic perspective based in the linguistic and cultural knowledge of their communities, which enabled these resources to be brought into mainstream learning, thus creating a syncretic curriculum that led to an increase in agency of children and their families as well as teachers themselves. We argue that collaboration between complementary and mainstream teacher colleagues can play a crucial role in constructing a space for multilingual learning in a monolingualizing society
Simultaneous targeted exchange of two nucleotides by single-stranded oligonucleotides clusters within a region of about fourteen nucleotides
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