The Experts below are selected from a list of 10017 Experts worldwide ranked by ideXlab platform
Ergin Atalar - One of the best experts on this subject based on the ideXlab platform.
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miniaturized fiber optic transmission system for mri signals
Magnetic Resonance in Medicine, 2008Co-Authors: Omer Gokalp Memis, Yigitcan Eryaman, Orhan Aytur, Ergin AtalarAbstract:Conventional MRI instruments transmit received MRI signals through Electrical cables. Although this design has proved to be effective over the years, we report a fiber-optic system that addresses the needs of recent developments in MRI technology. One of these technologies is phased array coils with a high number of elements, where total size of interconnections is a primary problem, and other problem is internal MRI coils, where there is a need for improvements in safety. The Miniature FiberOptic Transmission (FOT) System was developed to address these issues. The system consists of a receiver coil with active detuning, a low-noise preamplifier, and a laser diode connected to a photodetector with fiber-optic cabling. The overall noise figure of the system is lower than 1 dB. Total power consumption is 50 mW, and the device is switchable with another fiberoptic line, which can also control active detuning. A prototype device was tested in a GE 1.5 Tesla MRI scanner, and several images were acquired with a signal to noise ratio similar to coaxial cabling. We believe that this design will reduce the cabling problems of arrays and enable placement of internal coils into body cavities with no safety hazard to the patient, such as Electrical Shock or burns. Magn Reson Med 59: 165–173, 2008. © 2007 Wiley-Liss, Inc.
Yasuhiro Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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behavioral alterations in response to fear provoking stimuli and tranylcypromine induced by perinatal exposure to bisphenol a and nonylphenol in male rats
Environmental Health Perspectives, 2004Co-Authors: Takayuki Negishi, Katsuyoshi Kawasaki, Shingo Suzaki, Haruna Maeda, Yoshiyuki Ishii, Shigeru Kyuwa, Yoichiro Kuroda, Yasuhiro YoshikawaAbstract:The purpose of this study was to examine whether perinatal exposure to two major environmental endocrine-disrupting chemicals, bisphenol A (BPA; 0.1 mg/kg/day orally) and nonylphenol [NP; 0.1 mg/kg/day (low dose) and 10 mg/kg/day (high dose) orally] daily from gestational day 3 to postnatal day 20 (transplacental and lactational exposures) would lead to behavioral alterations in the male offspring of F344 rats. Neither BPA nor NP exposure affected behavioral characteristics in an open-field test (8 weeks of age), in a measurement of spontaneous motor activity (12 weeks of age), or in an elevated plus-maze test (14 weeks of age). A passive avoidance test (13 weeks of age) showed that both BPA- and NP-treated offspring tended to delay entry into a dark compartment. An active avoidance test at 15 weeks of age revealed that BPA-treated offspring showed significantly fewer avoidance responses and low-dose NP-treated offspring exhibited slightly fewer avoidance responses. Furthermore, BPA-treated offspring significantly increased the number of failures to avoid Electrical unconditioned stimuli within 5-sec Electrical Shock presentation compared with the control offspring. In a monoamine-disruption test using 5 mg/kg (intraperitoneal) tranylcypromine (Tcy), a monoamine oxidase inhibitor, both BPA-treated and low-dose NP-treated offspring at 22–24 weeks of age failed to show a significant increment in locomotion in response to Tcy, whereas control and high-dose NP-treated offspring significantly increased locomotion behavior after Tcy injection. In addition, when only saline was injected during a monoamine-disruption test, low-dose NP-treated offspring showed frequent rearing compared with the control offspring. The present results indicate that perinatal low-dose BPA or NP exposure irreversibly influenced the reception of fear-provoking stimuli (e.g., Electrical Shock), as well as monoaminergic neural pathways.
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behavioral alterations in response to fear provoking stimuli and tranylcypromine induced by perinatal exposure to bisphenol a and nonylphenol in male rats
Environmental Health Perspectives, 2004Co-Authors: Takayuki Negishi, Katsuyoshi Kawasaki, Shingo Suzaki, Haruna Maeda, Yoshiyuki Ishii, Shigeru Kyuwa, Yoichiro Kuroda, Yasuhiro YoshikawaAbstract:The purpose of this study was to examine whether perinatal exposure to two major environmental endocrine-disrupting chemicals, bisphenol A (BPA; 0.1 mg/kg/day orally) and nonylphenol [NP; 0.1 mg/kg/day (low dose) and 10 mg/kg/day (high dose) orally] daily from gestational day 3 to postnatal day 20 (transplacental and lactational exposures) would lead to behavioral alterations in the male offspring of F344 rats. Neither BPA nor NP exposure affected behavioral characteristics in an open-field test (8 weeks of age), in a measurement of spontaneous motor activity (12 weeks of age), or in an elevated plus-maze test (14 weeks of age). A passive avoidance test (13 weeks of age) showed that both BPA- and NP-treated offspring tended to delay entry into a dark compartment. An active avoidance test at 15 weeks of age revealed that BPA-treated offspring showed significantly fewer avoidance responses and low-dose NP-treated offspring exhibited slightly fewer avoidance responses. Furthermore, BPA-treated offspring significantly increased the number of failures to avoid Electrical unconditioned stimuli within 5-sec Electrical Shock presentation compared with the control offspring. In a monoamine-disruption test using 5 mg/kg (intraperitoneal) tranylcypromine (Tcy), a monoamine oxidase inhibitor, both BPA-treated and low-dose NP-treated offspring at 22-24 weeks of age failed to show a significant increment in locomotion in response to Tcy, whereas control and high-dose NP-treated offspring significantly increased locomotion behavior after Tcy injection. In addition, when only saline was injected during a monoamine-disruption test, low-dose NP-treated offspring showed frequent rearing compared with the control offspring. The present results indicate that perinatal low-dose BPA or NP exposure irreversibly influenced the reception of fear-provoking stimuli (e.g., Electrical Shock), as well as monoaminergic neural pathways. Key words: behavior, bisphenol A, fear, learning, monoamine, nonylphenol.
P S Hamer - One of the best experts on this subject based on the ideXlab platform.
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the three phase ground fault circuit interrupter system a novel approach to prevent electrocution
IEEE Transactions on Industry Applications, 2010Co-Authors: P S HamerAbstract:There are many electrocutions that occur on three-phase 480- and 600-V systems, particularly 277- or 347-V lighting branch circuits. Ground-fault circuit interrupters (GFCIs) have saved many lives on 120- and 120-240-V single-phase systems since being introduced to the National Electrical Code (NEC) in 1971. Application of GFCIs at voltages higher than 120 V has not progressed because the higher voltages-to-ground result in higher capacitive charging current of branch and feeder circuits, which in turn leads to “nuisance trips.” This paper first describes the mechanism of Electrical Shock, let-go threshold current, and heart ventricular fibrillation. It then describes the three-phase GFCI System (GFCIS-3Ph) that overcomes nuisance tripping by a novel approach to sensing and tripping logic. The system is most applicable for lighting branch circuits due to the historical risk of these circuits, but the GFCIS-3Ph is also appropriate to be considered as an option for all three-phase branch or feeder circuits. Application of the GFCIS-3Ph technology has the potential to almost eliminate electrocution for persons who make direct contact between an energized phase conductor and ground on three-phase systems rated below 1000 V phase-to-phase.
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the three phase ground fault circuit interrupter system a novel approach to prevent electrocution
Petroleum and Chemical Industry Technical Conference, 2008Co-Authors: P S HamerAbstract:There are many electrocutions that occur on three-phase 480 and 600 volt systems, particularly 277 or 347 volt lighting branch circuits. Ground-fault circuit-interrupters (GFCIs) have saved many lives on 120 volt and 120-240 volt single-phase systems since being introduced to the National Electrical Codereg (NEC) in 1971. Application of GFCIs at voltages higher than 120 volts has not progressed because the higher voltages to ground result in higher capacitive charging current of branch and feeder circuits, which in turn leads to ldquonuisance trips.rdquo This paper first describes the mechanism of Electrical Shock, let-go threshold current, and heart ventricular fibrillation. It then describes the three-phase ground-fault circuit-interrupter system (GFCIS-3Ph) that overcomes nuisance tripping by a novel approach to sensing and tripping logic. The system is most applicable for lighting branch circuits due to the historical risk of these circuits, but the GFCIS-3Ph is also appropriate to be considered as an option for all three-phase branch or feeder circuits. Application of the GFCIS-3Ph technology has the potential to almost eliminate electrocution for persons who make direct contact between an energized phase conductor and ground on three-phase systems rated below 1000 volts, phase-to-phase.
Joseph E Dunsmoor - One of the best experts on this subject based on the ideXlab platform.
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thought suppression inhibits the generalization of fear extinction
Behavioural Brain Research, 2021Co-Authors: Augustin C Hennings, Sophia A Bibb, Jarrod A Lewispeacock, Joseph E DunsmoorAbstract:A challenge for translating fear extinction research into clinical treatments for stress and anxiety disorders is that extinction learning tends not to generalize beyond the treatment context. This may be because the hippocampus limits the expression of extinction memories. Consequently, downregulating the hippocampus may help to promote the generalization of extinction learning. One nonpharmacological strategy to downregulate hippocampal activity in humans is motivated forgetting, in which a participant deliberately attempts to suppress the encoding and/or retrieval of episodic memories. Here, we evaluated whether this strategy could facilitate extinction generalization by augmenting extinction training with thought suppression. Participants were threat conditioned using two conditioned stimulus (CS) categories paired with an Electrical Shock. Subsequently, during extinction training, one CS category was accompanied by thought suppression. Participants were tested for extinction generalization 24h later with conceptual variations of the extinguished stimuli. Contrary to our prediction, we found that extinction training paired with thought suppression resulted in enhanced Shock expectancy (i.e., worse generalization) relative to standard extinction. We conclude that thought suppression during memory encoding likely acts as an inhibitory cue that blocks the acquisition of extinction memories, and therefore may not be a viable tactic to promote extinction generalization in the treatment of anxiety disorders.
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role of conceptual knowledge in learning and retention of conditioned fear
Biological Psychology, 2012Co-Authors: Joseph E Dunsmoor, Alex Martin, Kevin S. LabarAbstract:Abstract Associating sensory cues with aversive outcomes is a relatively basic process shared across species. Yet higher-order cognitive processes likely contribute to associative fear learning in many circumstances, especially in humans. Here we ask whether fears can be acquired based on conceptual knowledge of object categories, and whether such concept-based fear conditioning leads to enhanced memory representations for conditioned objects. Participants were presented with a heterogeneous collection of images of animals and tools. Objects from one category were reinforced by an Electrical Shock, whereas the other category was never reinforced. Results confirmed concept-based fear learning through subjective report of Shock expectancy, heightened skin conductance responses, and enhanced 24 h recognition memory for items from the conditioned category. These results provide novel evidence that conditioned fear can generalize through knowledge of object concepts, and sheds light on the persistent nature of fear memories and category-based fear responses symptomatic of some anxiety disorders.
Takayuki Negishi - One of the best experts on this subject based on the ideXlab platform.
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behavioral alterations in response to fear provoking stimuli and tranylcypromine induced by perinatal exposure to bisphenol a and nonylphenol in male rats
Environmental Health Perspectives, 2004Co-Authors: Takayuki Negishi, Katsuyoshi Kawasaki, Shingo Suzaki, Haruna Maeda, Yoshiyuki Ishii, Shigeru Kyuwa, Yoichiro Kuroda, Yasuhiro YoshikawaAbstract:The purpose of this study was to examine whether perinatal exposure to two major environmental endocrine-disrupting chemicals, bisphenol A (BPA; 0.1 mg/kg/day orally) and nonylphenol [NP; 0.1 mg/kg/day (low dose) and 10 mg/kg/day (high dose) orally] daily from gestational day 3 to postnatal day 20 (transplacental and lactational exposures) would lead to behavioral alterations in the male offspring of F344 rats. Neither BPA nor NP exposure affected behavioral characteristics in an open-field test (8 weeks of age), in a measurement of spontaneous motor activity (12 weeks of age), or in an elevated plus-maze test (14 weeks of age). A passive avoidance test (13 weeks of age) showed that both BPA- and NP-treated offspring tended to delay entry into a dark compartment. An active avoidance test at 15 weeks of age revealed that BPA-treated offspring showed significantly fewer avoidance responses and low-dose NP-treated offspring exhibited slightly fewer avoidance responses. Furthermore, BPA-treated offspring significantly increased the number of failures to avoid Electrical unconditioned stimuli within 5-sec Electrical Shock presentation compared with the control offspring. In a monoamine-disruption test using 5 mg/kg (intraperitoneal) tranylcypromine (Tcy), a monoamine oxidase inhibitor, both BPA-treated and low-dose NP-treated offspring at 22–24 weeks of age failed to show a significant increment in locomotion in response to Tcy, whereas control and high-dose NP-treated offspring significantly increased locomotion behavior after Tcy injection. In addition, when only saline was injected during a monoamine-disruption test, low-dose NP-treated offspring showed frequent rearing compared with the control offspring. The present results indicate that perinatal low-dose BPA or NP exposure irreversibly influenced the reception of fear-provoking stimuli (e.g., Electrical Shock), as well as monoaminergic neural pathways.
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behavioral alterations in response to fear provoking stimuli and tranylcypromine induced by perinatal exposure to bisphenol a and nonylphenol in male rats
Environmental Health Perspectives, 2004Co-Authors: Takayuki Negishi, Katsuyoshi Kawasaki, Shingo Suzaki, Haruna Maeda, Yoshiyuki Ishii, Shigeru Kyuwa, Yoichiro Kuroda, Yasuhiro YoshikawaAbstract:The purpose of this study was to examine whether perinatal exposure to two major environmental endocrine-disrupting chemicals, bisphenol A (BPA; 0.1 mg/kg/day orally) and nonylphenol [NP; 0.1 mg/kg/day (low dose) and 10 mg/kg/day (high dose) orally] daily from gestational day 3 to postnatal day 20 (transplacental and lactational exposures) would lead to behavioral alterations in the male offspring of F344 rats. Neither BPA nor NP exposure affected behavioral characteristics in an open-field test (8 weeks of age), in a measurement of spontaneous motor activity (12 weeks of age), or in an elevated plus-maze test (14 weeks of age). A passive avoidance test (13 weeks of age) showed that both BPA- and NP-treated offspring tended to delay entry into a dark compartment. An active avoidance test at 15 weeks of age revealed that BPA-treated offspring showed significantly fewer avoidance responses and low-dose NP-treated offspring exhibited slightly fewer avoidance responses. Furthermore, BPA-treated offspring significantly increased the number of failures to avoid Electrical unconditioned stimuli within 5-sec Electrical Shock presentation compared with the control offspring. In a monoamine-disruption test using 5 mg/kg (intraperitoneal) tranylcypromine (Tcy), a monoamine oxidase inhibitor, both BPA-treated and low-dose NP-treated offspring at 22-24 weeks of age failed to show a significant increment in locomotion in response to Tcy, whereas control and high-dose NP-treated offspring significantly increased locomotion behavior after Tcy injection. In addition, when only saline was injected during a monoamine-disruption test, low-dose NP-treated offspring showed frequent rearing compared with the control offspring. The present results indicate that perinatal low-dose BPA or NP exposure irreversibly influenced the reception of fear-provoking stimuli (e.g., Electrical Shock), as well as monoaminergic neural pathways. Key words: behavior, bisphenol A, fear, learning, monoamine, nonylphenol.