Spectrum investigation of pulse-interval modulation

1985 ◽  
Vol 59 (5) ◽  
pp. 597-601 ◽  
Author(s):  
R. S. FYATH ◽  
S. A. ABDULLAH ◽  
A. M. GLASS
Keyword(s):  
Pulse Interval ◽  
Spectrum Investigation

Androgenic and oestrogenic steroid participation in feedback control of luteinizing hormone secretion in male sheep

1983 ◽  
Vol 102 (4) ◽  
pp. 499-504 ◽  
Author(s):  
M. J. D'Occhio ◽  
B. D. Schanbacher ◽  
J. E. Kinder
Keyword(s):  
Luteinizing Hormone ◽  
Pulse Generator ◽  
Hormone Secretion ◽  
Pulse Interval ◽  
Serum Concentrations ◽  
Luteinizing Hormone Secretion ◽  
Lh Release ◽  
Lh Secretion ◽  
Additional Feedback ◽  
Male Sheep

Abstract. The acute castrate ram (wether) was used as an experimental model to investigate the site(s) of feedback on luteinizing hormone (LH) by testosterone, dihydrotestosterone and oestradiol. At the time of castration, wethers were implanted subdermally with Silastic capsules containing either crystalline testosterone (three 30 cm capsules), dihydrotestosterone (five 30 cm capsules) or oestradiol (one 6.5 cm capsule). Blood samples were taken at 10 min intervals for 6 h 2 weeks after implantation to determine serum steroid concentrations and to characterize the patterns of LH secretion. Pituitary LH response to exogenous LRH (5 ng/kg body weight) were also determined at the same time. The steroid implants produced serum concentrations of the respective hormones which were either one-third (testosterone) or two-to-four times (dihydrotestosterone, oestradiol) the levels measured in rams at the time of castration. Non-implanted wethers showed rhythmic pulses of LH (pulse interval 40–60 min) and had elevated LH levels (16.1 ± 1.6 ng/ml; mean ± se) 2 weeks after castration. All three steroids suppressed pulsatile LH release and reduced mean LH levels (to below 3 ng/ml) and pituitary LH responses to LRH. Inhibition of pulsatile LH secretion by all three steroids indicated that testosterone as well as its androgenic and oestrogenic metabolites can inhibit the LRH pulse generator in the hypothalamus. Additional feedback on the pituitary was indicated by the dampened LH responses to exogenous LRH.

scholarly journals Observation of Nociceptive Processing: Effect of Intra-Epidermal Electric Stimulus Properties on Detection Probability and Evoked Potentials

2021 ◽  
Vol 34 (2) ◽  
pp. 139-153
Author(s):  
Boudewijn van den Berg ◽  
Jan R. Buitenweg
Keyword(s):  
Evoked Potentials ◽  
Detection Probability ◽  
Pulse Interval ◽  
System Behavior ◽  
Stimulus Properties ◽  
Nociceptive System ◽  
Nociceptive Stimulus ◽  
Peripheral Nerve Fiber ◽  
Nociceptive Processing ◽  
Mixed Regression

AbstractMonitoring nociceptive processing is a current challenge due to a lack of objective measures. Recently, we developed a method for simultaneous tracking of psychophysical detection probability and brain evoked potentials in response to intra-epidermal stimulation. An exploratory investigation showed that we could quantify nociceptive system behavior by estimating the effect of stimulus properties on the evoked potential (EP). The goal in this work was to accurately measure nociceptive system behavior using this method in a large group of healthy subjects to identify the locations and latencies of EP components and the effect of single- and double-pulse stimuli with an inter-pulse interval of 10 or 40 ms on these EP components and detection probability. First, we observed the effect of filter settings and channel selection on the EP. Subsequently, we compared statistical models to assess correlation of EP and detection probability with stimulus properties, and quantified the effect of stimulus properties on both outcome measures through linear mixed regression. We observed lateral and central EP components in response to intra-epidermal stimulation. Detection probability and central EP components were positively correlated to the amplitude of each pulse, regardless of the inter-pulse interval, and negatively correlated to the trial number. Both central and lateral EP components also showed strong correlation with detection. These results show that both the observed EP and the detection probability reflect the various steps of processing of a nociceptive stimulus, including peripheral nerve fiber recruitment, central synaptic summation, and habituation to a repeated stimulus.

scholarly journals Research on Secure Debugging Interaction of Sensor Nodes Based on Visible Light Communication

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 953 ◽  
Author(s):  
Yuanchu Yin ◽  
Jiefan Qiu ◽  
Zhiqiang Li ◽  
Mingsheng Cao
Keyword(s):  
Visible Light ◽  
Channel Coding ◽  
Sensor Node ◽  
Source Coding ◽  
Visible Light Communication ◽  
Propagation Characteristic ◽  
Transmission Efficiency ◽  
Sensor Nodes ◽  
Pulse Interval ◽  
Inaccessible Area

When a wireless sensor node’s wireless communication fails after being deployed in an inaccessible area, the lost node cannot be repaired through a debugging interaction that relies on that communication. Visible light communication (VLC) as a supplement of radio wave communication can improve the transmission security at the physical layer due to its unidirectional propagation characteristic. Therefore, we implemented a VLC-based hybrid communication debugging system (HCDS) based on VLC using smartphone and sensor node. For the system’s downlink, the smartphone is taken as the VLC gateway and sends the debugging codes to the sensor node by the flashlight. To improve the transmission efficiency of the downlink, we also propose a new coding method for source coding and channel coding, respectively. For the source coding, we analyze the binary instructions and compress the operands using bitmask techniques. The average compression rate of the binary structure reaches 84.11%. For the channel coding, we optimize dual-header pulse interval (DH-PIM) and propose overlapped DH-PIM (ODH-PIM) by introducing a flashlight half-on state. The flashlight half-on state can improve the representation capability of individual symbols. For the uplink of HCDS, we use the onboard LED of the sensor node to transmit feedback debugging information to the smartphone. At the same time, we design a novel encoding format of DH-PIM to optimize uplink transmission. Experimental results show that the optimized uplink transmission time and BER are reduced by 10.71% and 22%, compared with the original DH-PIM.

scholarly journals Sensing Framework for the Internet of Actors in the Value Co-Creation Process with a Beacon-Attachable Indoor Positioning System

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 83
Author(s):  
Keiichi Zempo ◽  
Taiga Arai ◽  
Takuya Aoki ◽  
Yukihiko Okada
Keyword(s):  
Radio Wave ◽  
Indoor Positioning ◽  
Measurement Range ◽  
Pulse Interval ◽  
Retail Stores ◽  
Positioning System ◽  
Radio Waves ◽  
Positioning Systems ◽  
Environment Recognition ◽  
Indoor Positioning System

To evaluate and improve the value of a service, it is important to measure not only the outcomes, but also the process of the service. Value co-creation (VCC) is not limited to outcomes, especially in interpersonal services based on interactions between actors. In this paper, a sensing framework for a VCC process in retail stores is proposed by improving an environment recognition based indoor positioning system with high positioning performance in a metal shelf environment. The conventional indoor positioning systems use radio waves; therefore, errors are caused by reflection, absorption, and interference from metal shelves. An improvement in positioning performance was achieved in the proposed method by using an IR (infrared) slit and IR light, which avoids such errors. The system was designed to recognize many and unspecified people based on the environment recognition method that the receivers had installed, in the service environment. In addition, sensor networking was also conducted by adding a function to transmit payload and identification simultaneously to the beacons that were attached to positioning objects. The effectiveness of the proposed method was verified by installing it not only in an experimental environment with ideal conditions, but posteriorly, the system was tested in real conditions, in a retail store. In our experimental setup, in a comparison with equal element numbers, positioning identification was possible within an error of 96.2 mm in a static environment in contrast to the radio wave based method where an average positioning error of approximately 648 mm was measured using the radio wave based method (Bluetooth low-energy fingerprinting technique). Moreover, when multiple beacons were used simultaneously in our system within the measurement range of one receiver, the appropriate setting of the pulse interval and jitter rate was implemented by simulation. Additionally, it was confirmed that, in a real scenario, it is possible to measure the changes in movement and positional relationships between people. This result shows the feasibility of measuring and evaluating the VCC process in retail stores, although it was difficult to measure the interaction between actors.

scholarly journals Investigation of different stimulation patterns with doublet pulses to reduce muscle fatigue

2019 ◽  
Vol 6 ◽  
pp. 205566831982580 ◽  
Author(s):  
Ruslinda Ruslee ◽  
Jennifer Miller ◽  
Henrik Gollee
Keyword(s):  
Electrical Stimulation ◽  
Muscle Fatigue ◽  
Functional Electrical Stimulation ◽  
Muscle Activation ◽  
Motor Units ◽  
Pulse Interval ◽  
Time Interval ◽  
Fatigue Index ◽  
Significant Difference ◽  
Cord Injury

Introduction: Functional electrical stimulation is a common technique used in the rehabilitation of individuals with a spinal cord injury to produce functional movement of paralysed muscles. However, it is often associated with rapid muscle fatigue which limits its applications. Methods: The objective of this study is to investigate the effects on the onset of fatigue of different multi-electrode patterns of stimulation via multiple pairs of electrodes using doublet pulses: Synchronous stimulation is compared to asynchronous stimulation patterns which are activated sequentially (AsynS) or randomly (AsynR), mimicking voluntary muscle activation by targeting different motor units. We investigated these three different approaches by applying stimulation to the gastrocnemius muscle repeatedly for 10 min (300 ms stimulation followed by 700 ms of no-stimulation) with 40 Hz effective frequency for all protocols and doublet pulses with an inter-pulse-interval of 6 ms. Eleven able-bodied volunteers (28 ± 3 years old) participated in this study. Ultrasound videos were recorded during stimulation to allow evaluation of changes in muscle morphology. The main fatigue indicators we focused on were the normalised fatigue index, fatigue time interval and pre-post twitch–tetanus ratio. Results: The results demonstrate that asynchronous stimulation with doublet pulses gives a higher normalised fatigue index (0.80 ± 0.08 and 0.87 ± 0.08) for AsynS and AsynR, respectively, than synchronous stimulation (0.62 ± 0.06). Furthermore, a longer fatigue time interval for AsynS (302.2 ± 230.9 s) and AsynR (384.4 ± 279.0 s) compared to synchronous stimulation (68.0 ± 30.5 s) indicates that fatigue occurs later during asynchronous stimulation; however, this was only found to be statistically significant for one of two methods used to calculate the group mean. Although no significant difference was found in pre-post twitch–tetanus ratio, there was a trend towards these effects. Conclusion: In this study, we proposed an asynchronous stimulation pattern for the application of functional electrical stimulation and investigated its suitability for reducing muscle fatigue compared to previous methods. The results show that asynchronous multi-electrode stimulation patterns with doublet pulses may improve fatigue resistance in functional electrical stimulation applications in some conditions.

Evaluation of baroreceptor reflex by blood pressure monitoring in unanesthetized cats

1988 ◽  
Vol 254 (2) ◽  
pp. H377-H383 ◽  
Author(s):  
G. Bertinieri ◽  
M. Di Rienzo ◽  
A. Cavallazzi ◽  
A. U. Ferrari ◽  
A. Pedotti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Regression Coefficient ◽  
Blood Pressure Monitoring ◽  
Sinus Node ◽  
Pulse Interval ◽  
Pressure Monitoring ◽  
Physiological Conditions ◽  
Average Variation

The arterial baroreceptor control of the sinus node operating in unanesthetized conditions was evaluated in 10 cats in which blood pressure was recorded intra-arterially and scanned by a computer to identify the "spontaneous" sequences of three or more consecutive beats in which systolic blood pressure (SBP) progressively rose and pulse interval (PI) progressively lengthened (type 1 sequences) or SBP progressively fell and PI progressively shortened (type 2 sequences). Many type 1 and 2 three-beat sequences were found; four-, five-, and six-beat sequences of either type were progressively less common, and sequences longer than six beats were almost never identified. The regression coefficient was 30% greater for type 1 than for type 2 sequences. However a prominent feature of either regression coefficient was a wide scattering in each cat (average variation coefficient 50.9 +/- 5.5%). The regression coefficient values were related to some extent to the PI but not to the SBP existing at the beginning of the sequence. Sinoaortic denervation dramatically reduced the number of sequences of either type. These data validate a method for collecting a large number of observations on the baroreceptor-heart rate reflex in physiological conditions. This method may improve understanding of baroreflex involvement in integrated cardiovascular regulation.

scholarly journals Decreased endothelial nitric oxide, systemic oxidative stress, and increased sympathetic modulation contribute to hypertension in obese rats

2014 ◽  
Vol 306 (10) ◽  
pp. H1472-H1480 ◽  
Author(s):  
Natalia Veronez da Cunha ◽  
Phileno Pinge-Filho ◽  
Carolina Panis ◽  
Bruno Rodrigues Silva ◽  
Laena Pernomian ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lipid Peroxidation ◽  
Endothelial Cells ◽  
Arterial Pressure ◽  
Vascular Reactivity ◽  
Monosodium Glutamate ◽  
Saline Control ◽  
Pulse Interval ◽  
No Production ◽  
Obese Rats

We investigated the involvement of nitric oxide (NO) and reactive oxygen species (ROS) on autonomic cardiovascular parameters, vascular reactivity, and endothelial cells isolated from aorta of monosodium glutamate (MSG) obese rats. Obesity was induced by administration of 4 mg/g body wt of MSG or equimolar saline [control (CTR)] to newborn rats. At the 60th day, the treatment was started with NG-nitro-l-arginine methyl ester (l-NAME, 20 mg/kg) or 0.9% saline. At the 90th day, after artery catheterization, mean arterial pressure (MAP) and heart rate were recorded. Plasma was collected to assess lipid peroxidation. Endothelial cells isolated from aorta were evaluated by flow cytometry and fluorescence intensity (FI) emitted by NO-sensitive dye [4,5-diaminofluoresceindiacetate (DAF-2DA)] and by ROS-sensitive dye [dihydroethidium (DHE)]. Vascular reactivity was made by concentration-response curves of acetylcholine. MSG showed hypertension compared with CTR. Treatment with l-NAME increased MAP only in CTR. The MSG induced an increase in the low-frequency (LF) band and a decrease in the high-frequency band of pulse interval. l-NAME treatment increased the LF band of systolic arterial pressure only in CTR without changes in MSG. Lipid peroxidation levels were higher in MSG and were attenuated after l-NAME. In endothelial cells, basal FI to DAF was higher in CTR than in MSG. In both groups, acetylcholine increased FI for DAF from basal. The FI baseline to DHE was higher in MSG than in CTR. Acetylcholine increased FI to DHE in the CTR group, but decreased in MSG animals. We suggest that reduced NO production and increased production of ROS may contribute to hypertension in obese MSG animals.

Modulation of carotid baroreflex responsiveness in man: effects of posture and propranolol

1976 ◽  
Vol 41 (3) ◽  
pp. 383-387 ◽  
Author(s):  
D. L. Eckberg ◽  
F. M. Abboud ◽  
A. L. Mark
Keyword(s):  
Angina Pectoris ◽  
Supine Position ◽  
Baroreflex Sensitivity ◽  
Pulse Interval ◽  
Upright Posture ◽  
Adrenergic Stimulation ◽  
Interval Prolongation ◽  
Carotid Baroreflex ◽  
Before And After ◽  
Autonomic Blockade

Carotid baroreceptors were stimulated with graded neck suction in supine and standing volunteers, before and after autonomic blockade, to determine the influence of posture on baroreflex responsiveness. Propranolol significantly augmented baroreflex pulse interval prolongation in the supine position. Upright posture did not modify baroreflex pulse interval responses prior to propranolol, but significantly augmented responses after propranolol. The results suggest that standing enhances baroreflex sensitivity, but that under normal circumstances, this effect is masked by beta-adrenergic stimulation. Augmentation of baroreflex pulse interval prolongation in the supine and standing positions by propranolol may contribute to the effectiveness of this drug in angina pectoris and labile hypertension.

Sign in / Sign up

Export Citation Format

Share Document