Control of discharge patterns of medullary respiratory neurons by pulmonary vagal afferent inputs

1987 ◽  
Vol 253 (6) ◽  
pp. R809-R820 ◽  
Author(s):  
E. J. Zuperku ◽  
F. A. Hopp
Keyword(s):  
Linear Functions ◽  
Step Response ◽  
Respiratory Neurons ◽  
Step Frequency ◽  
Test Input ◽  
Linear Relationships ◽  
Vagal Afferent ◽  
The Difference ◽  
Time Courses ◽  
Discharge Patterns

To provide a better understanding of the central mechanisms by which pulmonary afferents reflexly control breathing, the responses of single respiratory neurons to vagal afferent patterns were analyzed. Respiratory-related unit (RRU) recordings were obtained from inspiratory (I), expiratory (E), and phase-spanning neurons in the ventral medulla of halothane-anesthetized, paralyzed, ventilated, vagotomized, mongrel dogs. Electrical stimulation of the largest vagal fibers was used to reflexly alter I and E durations (TI and TE) and to present various temporal input patterns to RRU. The net response was quantified by taking the difference between cycle-triggered histograms (CTH) of activity obtained during an input and the spontaneous control (no input) CTH. For step frequency patterns confined to either the I or E phase, 127 responses in 41 neurons were analyzed. The average step response time was greater than 500 ms. In general the time courses of the control and test-input discharge patterns were linearly related to one another. For I neurons the slopes (beta) of these relationships were linear functions of the vagal step frequency (Fv). Linear relationships were also obtained for 1/TI vs. Fv and 1/beta vs. TI. These results suggest that the vagal control of the discharge patterns of these neurons and phase timing is mediated via a process similar to gain modulation.

scholarly journals Differential Influence of Age on the Relationship between Genetic Mismatch and A(H1N1)pdm09 Vaccine Effectiveness

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 619
Author(s):  
Lirong Cao ◽  
Shi Zhao ◽  
Jingzhi Lou ◽  
Hong Zheng ◽  
Renee W. Y. Chan ◽  
...  
Keyword(s):  
Age Groups ◽  
The Elderly ◽  
Vaccine Effectiveness ◽  
Amino Acid Mutation ◽  
Epidemic Season ◽  
Vaccine Component ◽  
Linear Relationships ◽  
The Difference ◽  
Middle Aged Adults ◽  
The Relationship

Assessment of influenza vaccine effectiveness (VE) and identification of relevant influencing factors are the current priorities for optimizing vaccines to reduce the impacts of influenza. To date, how the difference between epidemic strains and vaccine strains at genetic scale affects age-specific vaccine performance remains ambiguous. This study investigated the association between genetic mismatch on hemagglutinin and neuraminidase genes and A(H1N1)pdm09 VE in different age groups with a novel computational approach. We found significant linear relationships between VE and genetic mismatch in children, young adults, and middle-aged adults. In the children’s group, each 3-key amino acid mutation was associated with an average of 10% decrease in vaccine effectiveness in a given epidemic season, and genetic mismatch exerted no influence on VE for the elderly group. We demonstrated that present vaccines were most effective for children, while protection for the elderly was reduced and indifferent to vaccine component updates. Modeling such relationships is practical to inform timely evaluation of VE in different groups of populations during mass vaccination and may inform age-specific vaccination regimens.

Interaction between chemoreceptor and stretch receptor inputs at medullary respiratory neurons

1994 ◽  
Vol 266 (6) ◽  
pp. R1951-R1961 ◽  
Author(s):  
J. Bajic ◽  
E. J. Zuperku ◽  
M. Tonkovic-Capin ◽  
F. A. Hopp
Keyword(s):  
Time Course ◽  
Afferent Input ◽  
Respiratory Neurons ◽  
Neuronal Responses ◽  
Additive Interaction ◽  
Dorsal Respiratory Group ◽  
Afferent Inputs ◽  
Discharge Patterns ◽  
Carotid Body Chemoreceptors ◽  
Common Carotid Arteries

The interaction between afferent inputs from carotid body chemoreceptors (CCRs) and from slowly adapting pulmonary stretch receptors (PSRs) on the discharge patterns of medullary inspiratory (I) and expiratory (E) neurons was characterized in thiopental sodium-anesthetized, paralyzed, ventilated dogs. A cycle-triggered ventilator was used to produce control and test pulmonary afferent input patterns. The CCRs were stimulated by phase-synchronized bolus injections of CO2-saturated saline into the common carotid arteries. Only those neurons whose discharge time course was altered by both inflation and CCR activation were studied. The dorsal respiratory group (DRG) I inflation-insensitive neurons were also included. Cycle-triggered histograms of unit activity were obtained for the neuronal responses to inflation, CO2 bolus, and their combination, as well as for the spontaneous control condition. Linearity of the interaction was tested by comparing the sum of the net individual responses to the net response of the combined afferent inputs. The results suggest that a linear (additive) interaction between CCR and PSR inputs exists for the DRG I inflation-sensitive neurons, the ventral respiratory group (VRG) I decrementing, and caudal VRG E augmenting neurons, while a nonadditive interaction exists for caudal VRG E decrementing bulbospinal neurons. The implications of these findings are discussed.

Relationship between the Differences of Odor Detection Threshold Values Measured by Different Methods and some of the Physicochemical Properties

2013 ◽  
Vol 807-809 ◽  
pp. 451-455 ◽  
Author(s):  
Di Fang ◽  
Jie Min Liu ◽  
Qin Yi
Keyword(s):  
Physicochemical Properties ◽  
Functional Group ◽  
Saturated Vapor ◽  
Detection Threshold ◽  
Threshold Values ◽  
Odor Detection ◽  
Linear Relationships ◽  
Odor Detection Threshold ◽  
The Difference ◽  
The Relationship

The amount of sample can enter the nasal cavity depends on the physiochemical characteristics such as distribution, volatility and solubility. It can be suspected that the difference of odor detection threshold (ODT) measured by different methods is related to the physicochemical properties of compounds. To investigate the relationship between ODT differences and the physicochemical properties of compounds, ODT values of four series of organic compounds were measured by triangle odor bag method and gas chromatography and olfactometry method; the results were compared and the absolute differences were calculated. Relationship between ODT differences and the type of functional group and some of the physicochemical properties of compounds was analyzed. The results showed the type of functional group had significant effect on the differences. Certain linear relationships between the logarithmic value of differences and the logarithmic values of saturated vapor pressure and molecular weight were observed.

Measurement error-filtered machine learning in digital soil mapping

2021 ◽  
Author(s):  
Stephan van der Westhuizen ◽  
Gerard Heuvelink ◽  
David Hofmeyr
Keyword(s):  
Machine Learning ◽  
Measurement Error ◽  
Soil Property ◽  
Soil Mapping ◽  
Digital Soil Mapping ◽  
Simulation Studies ◽  
True Value ◽  
Linear Relationships ◽  
The Difference ◽  
The Relationship

<p>Digital soil mapping (DSM) may be defined as the use of a statistical model to quantify the relationship between a certain observed soil property at various geographic locations, and a collection of environmental covariates, and then using this relationship to predict the soil property at locations where the property was not measured. It is also important to quantify the uncertainty with regards to prediction of these soil maps. An important source of uncertainty in DSM is measurement error which is considered as the difference between a measured and true value of a soil property.</p><p>The use of machine learning (ML) models such as random forests (RF) has become a popular trend in DSM. This is because ML models tend to be capable of accommodating highly non-linear relationships between the soil property and covariates. However, it is not clear how to incorporate measurement error into ML models. In this presentation we will discuss how to incorporate measurement error into some popular ML models, starting with incorporating weights into the objective function of ML models that implicitly assume a Gaussian error. We will discuss the effect that these modifications have on prediction accuracy, with reference to simulation studies.</p>

Processing of pulmonary afferent input patterns by respiratory I-beta neurons

1989 ◽  
Vol 256 (2) ◽  
pp. R379-R393 ◽  
Author(s):  
J. Bajic ◽  
E. J. Zuperku ◽  
F. A. Hopp
Keyword(s):  
Transpulmonary Pressure ◽  
Afferent Input ◽  
Central Component ◽  
Beta Activity ◽  
Neuronal Responses ◽  
Lung Inflation ◽  
Inhibitory Component ◽  
The Difference ◽  
Discharge Patterns ◽  
Fixed Times

To characterize the dynamics of the control of respiratory I-beta neurons by slowly adapting pulmonary stretch receptors, the neuronal discharge responses to lung inflation and electrically induced vagal input patterns were analyzed. Unitary recordings from single medullary I-beta neurons and whole phrenic nerve activity were recorded in chloralose-urethan-anesthetized paralyzed cats. Neuronal discharge patterns were quantified in terms of cycle-triggered histograms. The net response to a test afferent input pattern generated during neural inspiration was expressed as the difference between the central component of I-beta activity and the total response. The central component was obtained during control respiratory cycles in which lung inflation occurred during neural expiration and no vagal feedback occurred during neural inspiration. For a set of test inflations with different ramp rates, the net responses, measured at fixed times with respect to the onset of neural inspiration, were linearly related to transpulmonary pressure. However, the slopes of these relationships increased as a function of time during neural inspiration. Neuronal responses to electrically induced ramp vagal input patterns were similar to those produced by ramp inflation. The net response due to electrically induced ipsilateral step patterns consisted of a rapid excitatory and a slow inhibitory component, whereas only the slow inhibitory component was observed for contralateral patterns. The implications of these findings with respect to the modes of neural processing and effects on phrenic output patterns are discussed.

Method of quantifying the loss of acidification activity of lactic acid starters during freezing and frozen storage

2000 ◽  
Vol 67 (1) ◽  
pp. 83-90 ◽  
Author(s):  
FERNANDA FONSECA ◽  
CATHERINE BÉAL ◽  
GEORGES CORRIEU
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Storage Time ◽  
Frozen Storage ◽  
Operating Conditions ◽  
Linear Relationships ◽  
Before And After ◽  
Acidification Activity ◽  
The Difference ◽  
And Storage

We have developed a method to quantify the resistance to freezing and frozen storage of lactic acid starters, based on measuring the time necessary to reach the maximum acidification rate in milk (tm) using the Cinac system. Depending on the operating conditions, tm increased during the freezing step and storage. The loss of acidification activity during freezing was quantified by the difference (Δtm) between the tm values of the concentrated cell suspension before and after freezing. During storage at −20 °C, linear relationships between tm and the storage time were established. Their slope, k, allowed the quantitation of the decrease in acidification activity during 9–14 weeks of frozen storage. The method was applied to determine the resistance to freezing and frozen storage of four strains of lactic acid bacteria and to quantify the cryoprotective effect of glycerol.

Comparison of geotourism assessment models: and experiment in Bakony–Balaton UNSECO Global Geopark, Hungary

2018 ◽  
Vol 9 (2) ◽  
pp. 1-13 ◽  
Author(s):  
Márton Pál ◽  
Gáspár Albert
Keyword(s):  
Cultural Values ◽  
Future Development ◽  
Assessment Model ◽  
Linear Functions ◽  
Geological Maps ◽  
Realistic View ◽  
The Difference ◽  
Geosite Assessment ◽  
Physical Elements ◽  
Additional Value

Abstract Geological and scenic values of locations are the non-living curiosities that can be preserved and popularized a lot easier using the institutional background of geotourism, such as geoparks. UNESCO Global Geoparks Network is responsible for protecting and fostering natural, scenic and cultural values and especially geosites that are the exciting visible physical elements. Our goal was to quantify the geotourism potential around Csopak, a scenic village in the Balaton Uplands giving home for the headquarter of the Bakony-Balaton UNESCO Global Geopark. After designating 216 potential geosites using topographic and geological maps, we applied two assessment models: the Geosite Assessment Model (GAM) and the Modified Geosite Assessment Model (M-GAM). GAM has been applied with good results in Hungary on different areas, but M-GAM has not been used before. As M-GAM involves tourists into the process counting with their opinion, it may give a more realistic view of the geosites. The two methods produced different but comparable final values of geotourism potential counted from the Main Value and Additional Value scores. We discovered that the proportion of the difference of these values carries major information. The ratio of ΔAV/ΔMV used as linear functions and depicted on diagrams can derive which values are more important for the visitors. From this result we can draw conclusions about the future development trends: scientific or infrastructural values should be more effectively fostered. Using our results, geosites can be handled and developed as visitors expect it.

The half-life of the cytochrome bf complex in leaves of pea plants after transfer from moderately-high growth light to low light

2017 ◽  
Vol 44 (3) ◽  
pp. 351 ◽  
Author(s):  
Hui Zhu ◽  
Ling-Da Zeng ◽  
Xiao-Ping Yi ◽  
Chang-Lian Peng ◽  
Wang-Feng Zhang ◽  
...  
Keyword(s):  
Half Life ◽  
Time Course ◽  
Photosynthetic Capacity ◽  
High Growth ◽  
Limiting Factor ◽  
Low Light ◽  
High Photosynthetic Capacity ◽  
Growth Irradiance ◽  
The Difference ◽  
Time Courses

The content of cytochrome (cyt) bf complex is the main rate-limiting factor that determines light- and CO2-saturated photosynthetic capacity. A study of the half-life of the cyt f content in leaves was conducted whereby Pisum sativum L. plants, grown in moderately high light (HL), were transferred to low light (LL). The cyt f content in fully-expanded leaves decreased steadily over the 2 weeks after the HL-to-LL transfer, whereas control leaves in HL retained their high contents. The difference between the time courses of HL-to-LL plants and control HL plants represents the time course of loss of cyt f content, with a half-life of 1.7 days, which is >3-fold shorter than that reported for tobacco leaves at constant growth irradiance using an RNA interference approach (Hojka et al. 2014). After transfer to LL (16 h photoperiod), pea plants were re-exposed to HL for 0, 1.5 h or 5 h during the otherwise LL photoperiod, but the cyt f content of fully-expanded leaves declined practically at the same rate regardless of whether HL was re-introduced for 0, 1.5 h or 5 h during each 16 h LL photoperiod. It appears that fully-expanded leaves, having matured under HL, were unable to increase their cyt f content when re-introduced to HL. These findings are relevant to any attempts to maintain a high photosynthetic capacity when the growth irradiance is temporarily decreased by shading or overcast weather.

Effectiveness of a Spiral-Plate Heat Exchanger With Equal Capacitance Rates

2005 ◽  
Vol 128 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Louis C. Burmeister
Keyword(s):  
Heat Exchanger ◽  
Plate Heat Exchanger ◽  
Linear Functions ◽  
Transfer Coefficients ◽  
Archimedean Spiral ◽  
Plate Heat ◽  
Outer Periphery ◽  
Maximum Angle ◽  
The Difference ◽  
Spiral Plate

Abstract A formula is derived for the dependence of heat exchanger effectiveness on the number of transfer units for a spiral-plate heat exchanger with equal capacitance rates. The difference-differential equations that describe the temperature distributions of the two counter-flowing fluids, neglecting the effects of thermal radiation, are solved symbolically to close approximation. Provision is made for the offset inlet and exit of the hot and cold fluids at the outer periphery and for large heat transfer coefficients in the entrance regions. The peak effectiveness and the number of transfer units at which it occurs are linear functions of the maximum angle of the Archimedean spiral that describes the ducts; entrance region effects reduce both.

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