Resistance and Collapse in Bronchial Airways

1970 ◽  
Vol 38 (6) ◽  
pp. 767-782 ◽  
Author(s):  
P. Howard ◽  
I. W. Webster
Keyword(s):  
Air Flow ◽  
Forced Expiratory Volume ◽  
The Body ◽  
Alveolar Pressure ◽  
Functional Changes ◽  
Chest Disease ◽  
Acute Exacerbations ◽  
Forced Expiratory Flow ◽  
Obstructive Airways Disease ◽  
Airways Resistance

1. The Forced Expiratory Volume (FEV) was measured in normal persons and patients with obstructive airways disease at mouth pressures from 0 mmHg to levels high enough to prevent air flow altogether by using a Starling resistor at the mouth. 2. Evidence was obtained in support of the idea that, during forced expiratory flow, airways might function with the properties of a Starling resistor. This is considered to divide the airway into upstream and downstream segments at the site of airway collapse. The technique was simple, capable of being performed on outpatients and provided a means of studying the collapsibility of airways, airways resistance and alveolar pressure. 3. The FEV in normal persons and patients with disease was determined by the properties of the upstream segment. Since this segment contains only a proportion of the total airways resistance it was not surprising to find imprecise correlations between the FEV and airways resistance measured by the body plethysmograph. 4. Preliminary observations of patients during acute exacerbations of chest disease suggest that functional changes can occur throughout the length of the airway (i.e. in both upstream and downstream segments). 5. In the longer term during the natural history of obstructive airways disease, airways resistance and the more ready collapse of airways may develop independently. 6. Impaired alveolar pressure may contribute towards the reduction in air flow during acute exacerbations of chest disease.

Peripheral Airways Resistance, Static Recoil and the Forced Expiratory Volume

1972 ◽  
Vol 42 (4) ◽  
pp. 505-514 ◽  
Author(s):  
Ruth M. Cayton ◽  
P. Howard
Keyword(s):  
Forced Expiratory Volume ◽  
Second Phase ◽  
Forced Expiration ◽  
Elastic Recoil ◽  
Peripheral Airways ◽  
Mouth Pressure ◽  
History Of ◽  
Obstructive Airways Disease ◽  
Airways Resistance ◽  
Three Stages

1. The forced expiratory volume (FEV0·75) was measured at increasing mouth pressures in twenty-seven patients with obstructive airways disease. Attempts were made to divide the patients on clinical grounds into emphysematous, bronchitic or asthmatic categories; there was no evidence from the (FEV/mouth pressure) plots that their airways functioned differently during forced expiration. 2. Static elastic recoil was measured in twelve patients. There was no evidence that this factor alone caused the loss of FEV in any patient. 3. It is suggested that the use of the FEV as a test of respiratory function during the natural history of obstructive airways disease should be considered in three stages. There is an initial phase when peripheral airways disease develops with little or no alteration of the FEV. In the second phase the FEV decreases from normal values to below 1·0 litre, and at this stage is considered a sensitive indicator of peripheral airways resistance. In stage 3 the FEV is low and further changes can only be small. But airways resistance continues to increase and could be a more sensitive measurement of further airways disease.

Quantitative CT Image-Based Structural and Functional Changes during Asthma Acute Exacerbations

2021 ◽  
Author(s):  
Joonwoo Park ◽  
Sujeong Kim ◽  
Jae-Kwang Lim ◽  
Kwang Nam Jin ◽  
Min Suk Yang ◽  
...  
Keyword(s):  
Pulmonary Function Tests ◽  
Quantitative Computed Tomography ◽  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Imaging Features ◽  
Quantitative Ct ◽  
Functional Changes ◽  
Small Airway Disease ◽  
Acute Exacerbations ◽  
Residual Capacity

Asthma acute exacerbations (AE) have been investigated using quantitative computed tomography (QCT)-based imaging metrics, but QCT has not yet been used to investigate a comprehensive set of imaging metrics during AE. This study aims to explore imaging features, captured both at segmental and parenchymal scales, during asthma AE, compared to stable asthma (SA). Two sets of the QCT images at total lung capacity (TLC) and functional residual capacity (FRC) were captured for 14 subjects during asthma AE and in SA phase, respectively. We calculated airway wall thickness (WT), hydraulic diameter (Dh), and airway circularity (Cr) of the 36 segmental airways, percentage of functional small airway disease (fSAD%), percentage of emphysema, tissue fraction (βtiss), and coefficient of variation of βtiss (CV of βtiss). We performed Spearman correlation tests for changes in QCT metrics and pulmonary function tests, measured in AE and SA. During asthma AE, structural metrics, i.e., WT, Dh, and Cr, were not changed significantly. In functional metrics, CV of βtiss at FRC indicating the heterogeneity of lung tissue distribution was significantly increased, while the mean of βtiss at FRC did not change during AE. An increase of fSAD% during AE was most correlated with a decrease of forced expiratory volume in 1 second and forced vital capacity, especially in the lower lobes. This study demonstrates that the heterogeneous feature of βtiss measured at lower lobes is more noticeable during asthma AE, compared with other traditional imaging metrics. This metric could be utilized to identify unique features during asthma AE.

Dynamical Peculiarities of Concatenational Changes in Functional Cardiovascular Parameters

2018 ◽  
Vol 3 (82) ◽  
Author(s):  
Eurelija Venskaitytė ◽  
Jonas Poderys ◽  
Tadas Česnaitis
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Functional State ◽  
The Body ◽  
Functional Changes ◽  
High Intensity Training ◽  
Series Analysis ◽  
Greco Roman ◽  
St Segment ◽  
Standard Lead

Research  background  and  hypothesis.  Traditional  time  series  analysis  techniques,  which  are  also  used  for the analysis of cardiovascular signals, do not reveal the relationship between the  changes in the indices recorded associated with the multiscale and chaotic structure of the tested object, which allows establishing short-and long-term structural and functional changes.Research aim was to reveal the dynamical peculiarities of interactions of cardiovascular system indices while evaluating the functional state of track-and-field athletes and Greco-Roman wrestlers.Research methods. Twenty two subjects participated in the study, their average age of 23.5 ± 1.7 years. During the study standard 12 lead electrocardiograms (ECG) were recorded. The following ECG parameters were used in the study: duration of RR interval taken from the II standard lead, duration of QRS complex, duration of JT interval and amplitude of ST segment taken from the V standard lead.Research  results.  Significant  differences  were  found  between  inter-parametric  connections  of  ST  segment amplitude and JT interval duration at the pre and post-training testing. Observed changes at different hierarchical levels of the body systems revealed inadequate cardiac metabolic processes, leading to changes in the metabolic rate of the myocardium and reflected in the dynamics of all investigated interactions.Discussion and conclusions. It has been found that peculiarities of the interactions of ECG indices interactions show the exposure of the  functional changes in the body at the onset of the workload. The alterations of the functional state of the body and the signs of fatigue, after athletes performed two high intensity training sessions per day, can be assessed using the approach of the evaluation of interactions between functional variables. Therefore the evaluation of the interactions of physiological signals by using time series analysis methods is suitable for the observation of these processes and the functional state of the body.Keywords: electrocardiogram, time series, functional state.

FUNCTIONAL STATUS AND ADAPTIVE POTENTIAL IN FOREIGN STUDENTS WITH DIFFERENT TYPES OF VEGETATIVE REGULATION DURING TUITION

2020 ◽  
pp. 118-126
Author(s):  
A.M. Satarkulova
Keyword(s):  
Heart Rate ◽  
Foreign Students ◽  
Autonomic Regulation ◽  
The Body ◽  
Functional Changes ◽  
Different Types ◽  
Type 3 ◽  
Adaptive Abilities

The assessment and dynamic control over students’ status is a very important task. It allows timely detection of prenosological status prior to pathology and health maintenance in students. The objective of the paper is to assess the adaptive abilities of the body, to analyze changes in heart rate variability indicators in students with various types of autonomic regulation, to identify prenosological status and precursory pathological symptoms. Materials and Methods. The study enrolled 302 students from India, aged 21.54±1.43. Programming complex «Psychophysiologist» was used to register the main HRV parameters within 5 minutes. Health status was evaluated according to the index of functional changes and the scale of functional states. Results. N.I. Shlyk (2009) distinguished two groups of students with different types of autonomic regulation: type 1 (53 %) with moderate and type 2 (5 %) with marked characteristics of central regulation profile, type 3 (35 %) with moderate and type 4 (7 %) with marked characteristics of autonomous regulation profile. Main parameters of HRV and adaptation potential were defined for each student.All the parameters characterized functional and health status. Conclusions. It was shown that 82 % of trial subjects (type 1), 53 % (type 2), 94 % (type 3) and 95 % (type 4) demonstrated satisfactory adaptation and their physiological processes were at an optimal level. 18 % of students (type 1) demonstrated reduced adaptive abilities of the body. Moreover, they were under moderate stress. 47 % of subjects (type 2) were also under a significant stress, which was proven by excessively high SI, low SDNN and TP, and an increased index of functional changes. 5 % of students (type 4) revealed dysfunctional characteristics in the heart rhythm, peculiar to pathology. Keywords: foreign students, heart rate variability, types of autonomic regulation, adaptation potential, functional status. Оценка состояния студентов и динамический контроль за ним является важной задачей, поскольку позволяет своевременно выявлять у студентов донозологические состояния, предшествующие патологии, и способствовать сохранению здоровья. Цель. Оценка адаптивных возможностей организма, анализ изменений показателей вариабельности сердечного ритма у студентов с различными типами вегетативной регуляции, выявление донозологических состояний и ранних признаков патологии. Материалы и методы. В исследовании участвовало 302 студента в возрасте 21,54+1,43 года из Индии. Регистрировались основные параметры ВСР в течение 5 мин с использованием программно-аппаратного комплекса «Психофизиолог». Состояние и уровень здоровья оценивались по индексу функциональных изменений и шкале функциональных состояний. Результаты. По способу, предложенному Н.И. Шлык, выделены группы студентов с различными типами вегетативной регуляции: I (53 %) и II типы (5 %) – с умеренным и выраженным преобладанием центрального контура регуляции соответственно, III (35 %) и IV типы (7 %) – с умеренным и выраженным преобладанием автономного контура регуляции соответственно. У каждого из студентов определены основные параметры ВСР и адаптационного потенциала, характеризующие функциональное состояние и уровень здоровья. Выводы. Показано, что для 82 % обследуемых с I типом, 53 % со II типом, 94 % c III типом и 95 % с IV типом регуляции характерно состояние удовлетворительной адаптации, физиологические процессы сохраняются на оптимальном уровне. В группе студентов I типа у 18 % студентов адаптивные возможности организма снижены, выявлено состояние умеренного напряжения. У 47 % обследуемых II типа также зафиксировано состояние резко выраженного напряжения, индикатором которого является чрезмерно высокое значение SI, низкие величины SDNN и ТP, повышенное значение индекса функциональных изменений. В группе студентов с IV типом у 5 % учащихсяв регуляции ритма сердца выявлены дисфункциональные признаки, характерные для патологии. Ключевые слова: иностранные студенты, вариабельность сердечного ритма, типы вегетативной регуляции, адаптационный потенциал, функциональное состояние.

DOSE-DEPENDENT CHARACTER OF DISTURBANCE OF HEMATOPOIETIC AND IMMUNE SYSTEMS FUNCTION, PRODUCTION OF SOME HORMONES IN EXPERIMENTAL URANIUM ACETATE DIHYDRATE EXPOSURE

2021 ◽  
Vol 1 (1) ◽  
pp. 14-19
Author(s):  
Е. G. Trapeznikova ◽  
V. В. Popov ◽  
A. S. Radilov ◽  
V. V. Shilov
Keyword(s):  
Hematological Parameters ◽  
Chronic Administration ◽  
Absolute Number ◽  
Uranyl Acetate ◽  
The Body ◽  
Acetate Dihydrate ◽  
Functional Changes ◽  
Cd8 Cells ◽  
Tnf Α ◽  
Dose Dependent

The paper presents the results of an experimental study of the dose-dependent nature of functional changes in the body systems under chronic administration of uranyl acetate dihydrate in doses of 0.5 and 5.0 mg/kg per element for 18 weeks. The study was performed on 45 male outbred rats. It has been shown that uranyl acetate dihydrate in a dose of 0.5 mg/kg had no significant effect on hematological parameters. At the same time, activation of bactericidal activity of neutrophils, a decrease in the immunoregulatory index, and an increase in the blood concentration of tumor necrosis factor (TNF-α) have been revealed. The toxicant administered to rats in a dose of 5 mg/kg led to a decrease in the absolute number of erythrocytes, hemoglobin, hematocrit, platelets, the release of myelocytes into the blood, basophilia, monocytosis, the appearance of leukolysis cells and plasmatization of lymphocytes. On the part of the immune system, an increase in the biocidal capacity of neutrophilic granulocytes, TNF-α production, an increase in the number of CD8+ cells, and a reduction in the CD4+/CD8+ ratio have been found. Uranyl acetate dihydrate had a dose-dependent effect only on the number of cytotoxic T-lymphocytes, T-cells with the CD4+CD8+ phenotype, on the immunoregulatory index, and on the level of TNF-α. Hyperglycemia and glucosuria were also dose-dependent. An increase in glucose in the blood and urine indicated a violation of carbohydrate metabolism and kidney function. There was a decrease in the concentration of thyroxine, testosterone and an increase in the level of insulin. Uranyl acetate dihydrate led to the development of insulin resistance. The level of hormones did not depend on the dose of the toxicant administered to the animals.

Rack Level Modeling of Air Flow Through Perforated Tile in a Data Center

2012 ◽  
Author(s):  
Vaibhav K. Arghode ◽  
Pramod Kumar ◽  
Yogendra Joshi ◽  
Thomas S. Weiss ◽  
Gary Meyer
Keyword(s):  
Data Center ◽  
Body Force ◽  
Air Flow ◽  
The Body ◽  
Physical Models ◽  
Cfd Modeling ◽  
Computational Time ◽  
Force Model ◽  
Flow Through ◽  
Tile Surface

Effective air flow distribution through perforated tiles is required to efficiently cool servers in a raised floor data center. We present detailed computational fluid dynamics (CFD) modeling of air flow through a perforated tile and its entrance to the adjacent server rack. The realistic geometrical details of the perforated tile, as well as of the rack are included in the model. Generally models for air flow through perforated tiles specify a step pressure loss across the tile surface, or porous jump model based on the tile porosity. An improvement to this includes a momentum source specification above the tile to simulate the acceleration of the air flow through the pores, or body force model. In both of these models geometrical details of tile such as pore locations and shapes are not included. More details increase the grid size as well as the computational time. However, the grid refinement can be controlled to achieve balance between the accuracy and computational time. We compared the results from CFD using geometrical resolution with the porous jump and body force model solution as well as with the measured flow field using Particle Image Velocimetry (PIV) experiments. We observe that including tile geometrical details gives better results as compared to elimination of tile geometrical details and specifying physical models across and above the tile surface. A modification to the body force model is also suggested and improved results were achieved.

Abstract 156: Involvement of β-adrenergic System in Myocardial Dysfunction Induced by Obesity

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Ana Paula Lima-Leopoldo ◽  
Artur Ferron ◽  
Bruno Jacobsen ◽  
Dijon Campos ◽  
Renata Luvizotto ◽  
...  
Keyword(s):  
Myocardial Dysfunction ◽  
Myocardial Contraction ◽  
Experimental Models ◽  
The Body ◽  
Adrenergic System ◽  
Standard Diet ◽  
Adrenergic Stimulation ◽  
High Fat ◽  
Functional Changes ◽  
Adiposity Index

Several structural and functional changes of the heart have often been associated with human and experimental models of obesity. Some factors have been suggested as responsible for possible cardiac abnormalities in models of obesity, among them β-adrenergic system, an important mechanism of regulation of myocardial contraction and relaxation. The objetive of present study was to evaluate the . Thirty-day-old male Wistar rats were assigned to one of two groups: control (C) and obese (Ob). The C group was fed a standard diet and Ob group was fed cycles of four unsaturated high-fat diets for 15 weeks. The body fat was measured from the sum of the individual fat pad weights and the obesity was defined by adiposity index. Isolated papillary muscle preparation was performed under basal conditions and after inotropic and lusitropic maneuvers. β-adrenergic system was evaluated by using cumulative concentrations of isoproterenol and Western Blot. After 15 weeks, the Ob rats developed higher adiposity index than C rats. Obesity promoted comorbities such as glucose intolerance, insulin resistance, hyperleptinemia, and dyslipidemia; however, were not associated with changes in systolic blood pressure. The cardiac structure results post-death showed that obesity caused cardiac hypertrophy. Furthermore, Ob muscles developed similar baseline data, but myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca2+ was compromised. There were no changes in cardiac function between groups after β-adrenergic stimulation. The obesity was not accompanied by changes in protein expression of Gsα, β1 and β2 adrenergic receptors. In conclusion, the myorcardial dysfunction caused by unsaturated high-fat diet-induced obesity, after 15 weeks, is not related to β-adrenergic system impairment.

THE EFFECTS OF ALTERED AQUATIC AND AERIAL RESPIRATORY GAS CONCENTRATIONS ON AIR-BREATHING PATTERNS IN A PRIMITIVE FISH (AMIA CALVA)

1993 ◽  
Vol 181 (1) ◽  
pp. 81-94 ◽  
Author(s):  
M. S. Hedrick ◽  
D. R. Jones
Keyword(s):  
Air Flow ◽  
The Body ◽  
Type I ◽  
Type Ii ◽  
Breathing Frequency ◽  
Breathing Patterns ◽  
Flow Measurements ◽  
Air Breathing ◽  
Gas Bladder ◽  
Amia Calva

The mechanisms and physiological control of air-breathing were investigated in an extant halecomorph fish, the bowfin (Amia calva). Air flow during aerial ventilation was recorded by pneumotachography in undisturbed Amia calva at 20–24°C while aquatic and aerial gas concentrations were independently varied. Separation of aquatic and aerial gases was used in an attempt to determine whether Amia calva monitor and respond to changes in the external medium per se or to changes in dissolved gases within the body. Air flow measurements revealed two different types of ventilatory patterns: type I air-breaths were characterized by exhalation followed by inhalation; type II air-breaths, which have not been described previously in Amia calva, consisted of single inhalations with no expiratory phase. Expired volume (Vexp) for type I breaths ranged from 11.6+/−1.1 to 26.7+/− 2.9 ml kg-1 (95 % confidence interval; N=6) under normoxic conditions and was unaffected by changes in aquatic or aerial gases. Gas bladder volume (VB), determined in vitro, was 80 ml kg-1; the percentage of gas exchanged for type I breaths ranged from 14 to 33 % of VB in normoxia. Fish exposed to aquatic and aerial normoxia (PO2=19-21 kPa), or aerial hypercapnia (PCO2=4.9 kPa) in normoxic water, used both breath types with equal frequency. Aquatic or aerial hypoxia (PO2=6-7 kPa) significantly increased air-breathing frequency in four of eight fish and the ventilatory pattern changed to predominantly type I air-breaths (75–92 % of total breaths). When fish were exposed to 100 % O2 in the aerial phase while aquatic normoxia or hypoxia was maintained, air-breathing frequency either increased or did not change. Compared with normoxic controls, however, type II breaths were used almost exclusively (more than 98 % of total breaths). Type I breaths appear to be under feedback control from O2-sensitive chemoreceptors since they were stimulated by aquatic or aerial hypoxia and were nearly abolished by aerial hyperoxia. These results also indicate that Amia calva respond to changes in intravascular PO2; however, externally facing chemoreceptors that stimulate air-breathing in aquatic hypoxia cannot be discounted. Type II air- breaths, which occurred in aerial hyperoxia, despite aquatic hypoxia, appear to be stimulated by reductions of VB, suggesting that type II breaths are controlled by volume-sensitive gas bladder stretch receptors. Type II breaths are likely to have a buoyancy-regulating function.

FinFET Transistor Output Drive Performance Modification by Focused Ion Beam (FIB) Chip Circuit Editing

2020 ◽  
Author(s):  
Steven B. Herschbein ◽  
Kyle M. Winter ◽  
Carmelo F. Scrudato ◽  
Brian L. Yates ◽  
Edward S. Hermann ◽  
...  
Keyword(s):  
Structural Changes ◽  
Focused Ion Beam ◽  
Low Voltage ◽  
Ion Beam ◽  
Amorphous Material ◽  
The Body ◽  
Easy Access ◽  
Design Parameters ◽  
Chip Surface ◽  
Functional Changes

Abstract Focused Ion Beam (FIB) chip circuit editing is a well-established highly specialized laboratory technique for making direct changes to the functionality of integrated circuits. A precisely tuned and placed ion beam in conjunction with process gases selectively uncovers internal circuitry, create functional changes in devices or the copper wiring pattern, and reseals the chip surface. When executed within reasonable limits, the revised circuit logic functions essentially the same as if the changes were instead made to the photomasks used to fabricate the chip. The results of the intended revision, however, can be obtained weeks or months earlier than by a full fabrication run. Evaluating proposed changes through FIB modification rather than proceeding immediately to mask changes has become an integral part of the process for bringing advanced designs to market at many companies. The end product of the FIB process is the very essence of handcrafted prototyping. The efficacy of the FIB technique faces new challenges with every generation of fabrication process node advancement. Ever shrinking geometries and new material sets have always been a given as transistor size decreases and overall packing density increases. The biggest fundamental change in recent years was the introduction of the FinFET as a replacement for the venerable planar transistor. Point to point wiring change methodology has generally followed process scaling, but transistor deletions or modifications with the change to Fins require a somewhat different approach and much more careful control due to the drastic change in height and shape. We also had to take into consideration the importance of the 4th terminal, the body-tie, that is often lost in backside editing. Some designs and FET technology can function acceptably well when individual devices are no longer connected to the bulk substrate or well, while others can suffer from profound shifts in performance. All this presents a challenge given that the primary beam technology improvements of the fully configured chip edit FIB has only evolved incrementally during the same time period. The gallium column system appears to be reaching its maximum potential. Further, as gallium is a p-type metal dopant, there are limitations to its use in close proximity to certain active semiconductor devices. Amorphous material formation and other damage mechanisms that extend beyond what can be seen visually when endpointing must also be taken into account [1]. Device switching performance and even transmission line characteristics of nearby wiring levels can be impacted by material structural changes from implantation cascades. Last year our lab participated in a design validation exercise in which we were asked to modify the drive of a multi-finger FinFET device structure to reduce its switching speed impact on a circuit. The original sized device pulled the next node in the chain too fast, resulting in a timing upset. Deleting whole structures and bridging over/around them is commonly done, but modifications to the physical size of an FET device is a rare request and generally not attempted. It requires a level of precision in beam control and post-edit treatment that can be difficult to execute cleanly. Once again during a complex edit task we considered the use of an alternate ion beam species such as neon, or reducing the beam energy (low kV) on the gallium tool. Unfortunately, we don’t yet have easy access to a versatile viable replacement column technology grafted to a fully configured edit station. And while there should be significantly reduced implant damage and transistor functional change when a gallium column FIB is operated at lower accelerating potential [2], the further loss of visual acuity due to the reduced secondary emission, especially when combined with ultra-low beam currents, made fast and accurate navigation near impossible. We instead chose the somewhat unconventional approach of using an ultra-low voltage electron beam to do much of the navigation and surface marking prior to making the final edits with the gallium ion beam in a dual-beam FIB tool. Once we had resolved how to accurately navigate to the transistors in question and expose half of the structure without disturbing the body-tie, we were able to execute the required cut to trim away 50% of the structure and reduce the effective drive. Several of the FIB modified units functioned per the design parameters of a smaller sized device, giving confidence to proceed with the revised mask set. To our surprise, the gallium beam performed commendably well in this most difficult task. While we still believe that an inert beam of similar characteristics would be preferable, this work indicates that gallium columns are still viable at the 14 nm FinFET node for even the most rigorous of editing requirements. It also showed that careful application of e-beam imaging on the exposed underside of FinFET devices could be performed without degrading or destroying them.

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