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Flow Meter (flow + meter)
Selected AbstractsNew method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheepACTA PHYSIOLOGICA, Issue 2 2006T. Naito Abstract Aim:, Lung lymph has commonly been studied using a lymph fistula created by tube cannulation into the efferent duct of the caudal mediastinal node in sheep. In this method, the tail region of the caudal mediastinal node is resected and the diaphragm is cauterized to exclude systemic lymph contamination, and cannulation is performed into one of the multiple efferent ducts originating from the caudal mediastinal node. Moreover, the pumping activity of lymphatics might be diminished by cannulation. Therefore, the purpose of the study was to evaluate the flow rate of lung lymph with maintenance of intact lymphatic networks around the caudal mediastinal node to the thoracic duct in sheep. Methods:, An ultrasound transit-time flow meter was used to measure lung lymph flow. The thoracic duct was clamped just above the diaphragm and the flow probe was attached to the thoracic duct just after the last junction with an efferent duct from the caudal mediastinal node. The lung lymph flow rate was measured at baseline and under conditions of lung-oedema formation. Results:, The baseline lung lymph flow rate in our model was three- to sixfold greater than values obtained with the cannulation method. With oedema-formation, the lung lymph flow rate was the same as that measured using cannulation. Conclusion:, The lung lymph flow was unexpectedly large under the conditions of the study, and our data suggest that the drainage effect of lymphatics is significant as a safety factor against pulmonary oedema formation. [source] Xylem root and shoot hydraulics is linked to life history type in chaparral seedlingsFUNCTIONAL ECOLOGY, Issue 1 2010Robert B. Pratt Summary 1.,Shrubs in fire prone chaparral communities have evolved different life history types in response to fire. A key to understanding the evolution of life history type differences is to understand how physiological traits are linked to differences in life history type. Vascular adaptations are important for delivering an efficient and stable water supply to evergreen chaparral shrub leaves. This study tested for a link between vascular physiology and life history type in chaparral shrubs. 2.,Chaparral shrub species along the south-western coast of North America survive wildfire by three different life histories. Non-sprouters are killed by fire and re-establish exclusively through germination of fire-stimulated seeds, facultative sprouters re-establish by a combination of vegetative sprouting and fire-stimulated seeds, and obligate sprouters re-establish exclusively by vegetative sprouting because their seeds do not survive fire. Non-sprouters and facultative sprouters establish seedlings in the open canopy post fire environment, whereas obligate sprouters establish seedlings in the shady understory of the mature chaparral canopy. 3.,Seedlings of nine species (Rhamnaceae) representing three each of the different life history types were grown in deep containers in a common garden under treatments of sun and shade. Hydraulic conductance was measured using a high-pressure flow meter for all organs, and a vacuum technique was used to measure conductance of fine and woody roots. We predicted that non-sprouters would exhibit greater hydraulic efficiency than the sprouting species, and that facultative sprouters would be more efficient than the shade tolerant obligate sprouters. 4.,Non-sprouters had the greatest hydraulic conductance per unit leaf and sapwood area at the whole seedling level, whereas facultative and obligate sprouters were not different. Comparing hydraulic conductance across major organs (from fine roots to leaves) showed that the hydraulic system was well coordinated. At the whole seedling level, the root system was more of a bottleneck than the shoot system. This pattern was consistent with high resistance extraxylary pathways in roots and differences in root architecture. 5.,The greater hydraulic efficiency of the non-sprouter life history type is attributed to its post-fire pioneering habit and may partially explain the relatively high speciation in the non-sprouters. Lower hydraulic efficiency is associated with a sprouting life history and greater shade tolerance. The seedling root systems represent a hydraulic bottleneck that may place roots under especially intense selection. [source] Flume or weir continuous water flow rate recorder for irrigation use,,IRRIGATION AND DRAINAGE, Issue 1 2005Blair L. Stringam Abstract US Bureau of Reclamation projects and irrigation districts need simple, low-cost, robust devices to measure and record water use for effective water management decisions. This need has resulted in the development of a continuous flow meter and recorder (CFM). The CFM is designed to continuously measure flow rates through open channel measurement structures, such as flumes or weirs, by recording the water levels upstream. The water level measurements are then converted to flow rate using a simple weir power equation. The CFM consists of an easily programmed CPU, an LCD for displaying the flow rate and total amount of water that has passed through the measurement structure, and a water level sensor. The CFM, including a solar power supply, may be purchased for under US$1000. The majority of that cost is for the water level sensor and may be reduced depending upon the needed accuracy. Presently, some of these devices have been installed on irrigation systems in the field where they have been exposed to harsh weather conditions. Despite the harsh environments, the CFMs have been functioning as designed. This paper discusses the design, installation, and testing of the continuous flow meter. Published in © 2005 John Wiley & Sons, Ltd. [source] Selective activation of the sacral anterior roots for induction of bladder voidingNEUROUROLOGY AND URODYNAMICS, Issue 2 2006Narendra Bhadra Abstract Aim We investigated the efficacy of selective activation of the smaller diameter axons in the sacral anterior roots for electrically induced bladder voiding. Materials and Methods Acute experiments were conducted in five adult dogs. The anterior sacral roots S2 and S3 were implanted bilaterally with tripolar electrodes. Pressures were recorded from the bladder and from the proximal urethra and the external urethral sphincter. A detector and flow meter monitored fluid flow. A complete sacral dorsal rhizotomy was carried out. The effects of two types of pulse trains at 20 Hz were compared; quasitrapezoidal pulses (500 µsec with 500 µsec exponential decay) and interrupted rectangular (100 µsec, 2 sec on/2 sec off). Before rhizotomy, rectangular pulse trains (100 µsec) to activate all fibers were also applied. The experimental design was block randomized before and after rhizotomy. Results Quasitrapezoidal pulses showed block of sphincter activation with average minimum current for maximum suppression of 1.37 mA. All pulse types evoked average bladder pressures above the basal sphincter closure pressure. The pressure patterns in the proximal urethra closely followed the bladder pressures. Before dorsal rhizotomy, stimulation evoked a superadded increase in sphincter pressures with slow rise time. After rhizotomy, the sphincter pressure patterns followed the bladder pressures during selective activation and voiding occurred during stimulation with quasitrapezoidal trains and in between bursts with interrupted rectangular stimulation. Conclusions Selective activation of sacral ventral roots combined with dorsal rhizotomy may provide a viable means of low-pressure continuous voiding in neurological impairment. Neurourol. Urdynam. © 2005 Wiley-Liss, Inc. [source] Combined effects of arbuscular mycorrhizas and light on water uptake of the neotropical understory shrubs, Piper and PsychotriaNEW PHYTOLOGIST, Issue 2 2003Damond A. Kyllo Summary ,,Root hydraulic conductance (Kr) was measured for five understory shrub species of the neotropical moist forest to determine the effects of arbuscular mycorrhizas (AM) for both carbon-rich and carbon-limited host plants. ,,Kr was measured using a high pressure flow meter (HPFM) for potted plants grown in a factorial combination of AM fungi (presence/absence) and light (3.5 and 30% of full sun, low/high). ,,AM colonization improved Kr for the more shade-tolerant species plants when growing in low light. By contrast, water uptake efficiency of the light-demanding species was significantly decreased by AM fungi in high light. Regardless of AM colonization, light-demanding species had a lower capacity than shade-tolerant species to meet transpirational demands, and they allocated substantially more to fine root production relative to leaf area when colonized. ,,The differential effects of AM colonization and light on a species' root hydraulic conductance in relation to phylogeny and light adaptation demonstrate that AM fungi may be critical in determining early plant succession and community composition not only due to effects on nutrient uptake, but on water uptake as well. [source] The Hemodynamic Behavior of Arterial Anastomosis Using Fibrin Sealant: Experimental Study in SwineARTIFICIAL ORGANS, Issue 11 2008Eduardo A.V. Rocha Abstract The wide use of biological sealants as a reinforcement for arterial sutures and the small experimental base in literature motivated this study. Our aim was to evaluate the flow, tear pressure, and the need of reinforcement stitches in sutured arteries after a cross-section. This research project complied with the Helsinki convention. The Tissucol (Baxter) fibrin sealant was used in all experiments. The femoral and carotid arteries of 17 swine from the same breed (weighing from 15 to 20 kg) were cross-sectioned after heparinization and subjected to anastomoses using a single continuous plane of 7-0 prolene. We worked with 68 artery samples, 34 in the treatment group and 34 in the control group. For each animal, one carotid and one femoral artery randomly received fibrin sealant with the contralateral side being used as a control. The need and the number of reinforcement stitches were recorded. Ten minutes after protamine infusion, the animals were sacrificed and the arteries were catheterized respecting 1 cm proximal and distal. The arteries were measured and placed on a flow meter to evaluate the flow rate of 10 mL of 0.9% NaCl in a 50 cm high column. The arteries were then subjected to air infusion at increasingly higher pressures (stepwise increases of 25 mm Hg), the grafts were dipped in 0.9% NaCl solution, the first air leakage was observed, and the tear pressure recorded. Data was analyzed with EpiInfo 6 data manager. The external diameters and thickness of the arteries were similar in both the treatment and control group. There was no significant difference between the groups regarding the tear pressure (P = 0.329), flow rate (P = 0.943), and the number of samples with a tear pressure above 200 mm Hg. However, the sealant reduced the number of reinforcement stitches necessary (P = 0.029). We conclude that fibrin sealant reduces the need of additional stitches; however, it does not change the tear pressure nor significantly reduces the flow. [source] Asthma Outcomes at an Inner-City School-Based Health CenterJOURNAL OF SCHOOL HEALTH, Issue 1 2001Nicole Lurie§ ABSTRACT Childhood asthma has reached near-epidemic levels in the US cities. Innovative strategies to identify children with asthma and prevent asthma morbidity are needed. This study measured asthma outcomes after initiation of an inner-city elementary school health center with a schoolwide focus on asthma detection and treatment. The site was an inner-city elementary school in Minneapolis, Minn. The study design incorporated a pre and post comparison with a longitudinal cohort of children (n=67) and a cross-sectional cohort of children before (n=156) and after (n=114) the intervention. Hospitalization rates for asthma decreased 75% to 80% over the study period. Outpatient visits for care in the absence of asthma symptoms doubled (p<.01), and the percentage of students seeing a specialist for asthma increased (p<.01). Use of peak flow meters, use of asthma care plans, and use of inhalers also improved (p<.01). While no change occurred in school absenteeism, parents reported that their children had less awakening with asthma and that asthma was less disruptive to family plans. This schoolwide intervention that included identification of children with asthma, education, family support, and clinical care using an elementary school health center was effective in improving asthma outcomes for children. [source] How pediatricians manage asthma in ThailandPEDIATRIC PULMONOLOGY, Issue 2 2001Pakit Vichyanond MD Abstract Currently, there is no existing information regarding prescribing practices for the management of childhood asthma among pediatricians in Thailand. In order to evaluate the management standards for childhood asthma in Thailand, 400 self-administered questionnaires were randomly mailed to nonacademic pediatricians throughout Thailand, asking questions about their preferences in the treatment of childhood asthma. One hundred and seventy-four of these 400 questionnaires were returned (a response rate of 43.5%). Data were analyzed using the descriptive module of the Epi-info 6 program. For acute asthma, 17% of the respondents used objective measures such as peak flow meters in assessing asthma severity and severity of acute asthma attacks. The drug of first choice for treating acute attacks was a nebulized beta-agonist q 20 min (81.8%). Although 93% indicated that they had used theophylline for treating acute attacks, most would reserve the drug for patients with severe symptoms. Corticosteroids were reserved for those with severe attacks (91.7% both for clinic and for in-hospital settings). Hydrocortisone was the most preferred corticosteroid preparation (59.8%). Ninety-seven percent used antibiotics in treating acute asthma, but only with appropriate indications. For chronic asthma, a strong preference was observed for oral beta-agonists as the bronchodilator of choice (88%). For moderately severe asthmatics, theophylline was still preferred by 41% of the responders. Among prophylactic agents, ketotifen was the most favored drug (90.4%), whereas inhaled steroids and cromolyn were chosen by 9.6% and 2.4%, respectively. Eighty-five percent indicated that they would prescribe prophylactic agents for 1 year or less. Forty-two percent never considered allergy evaluation as a part of a workup for childhood asthma. Certain prescribing practices of childhood asthma management in Thailand were observed among pediatricians, i.e., 1) low frequency of using objective measures in assessing asthma severity among pediatricians; 2) frequent use of theophylline and antibiotics in the treatment of acute asthma; 3) late introduction of corticosteroids in treating acute asthma; 4) preference for oral bronchodilators; and 5) preference of ketotifen as the prophylactic drug of choice. This survey provides baseline data and will aid in the evaluation of management guidelines for childhood asthma in Thailand. Pediatr Pulmonol. 2001; 32:109,114. © 2001 Wiley-Liss, Inc. [source] | |||||||||||||