Search results for "flow [Keywords]"

Comparison of unconfined and confined unsaturated hydraulic conductivity

2007

Abstract The field tension infiltrometer (TI) and the laboratory unit hydraulic gradient (UHG) methods are widely applied to determine the near-saturated soil hydraulic conductivity, K . Comparison between the two methods is relevant given that they differ in the explored soil volume (undetached or detached) and in the flow process (unconfined or confined). The objective of this investigation was to compare unconfined and confined measurements of unsaturated hydraulic conductivity. Twenty TI experiments were conducted in a relatively coarse-textured soil having an appreciable hysteretic behavior by using two different dry-to-wet-to-dry (DTWTD) sequences of pressure head, h 0 , values that d…

A novel 2D process model of electrodialysis units in cross-flow layout for the assessment of membrane deformation effects

2022

How to Write a Research Protocol: Tips and Tricks

2018

There is a need to reassess the most appropriate indications for stress echocardiography in the current era, in patients with suspect or known coronary artery disease (CAD), and also the most helpful additional parameters that can be easily calculated in clinical practice to increase the known suboptimal sensitivity for obstructive CAD of this test. The current review tries to clarify what is and what should be the proper role for functional testing in general, but specifically regarding modern stress echocardiography in the current practice, for suspected CAD and/or atypical chest pain. Few candidate additional parameters beyond wall motion assessment are here suggested to improve diagnost…

Prevalence of nocturnal asthma in a general population sample: determinants and effect of aging.

2000

Nocturnal asthma (NA) is important because of clinical and prognostic implications. Previous data on prevalence may be overestimated, because they are derived from selected series. Observations on monitoring of peak expiratory flow in elderly asthmatics suggested that prevalence of NA may increase with age. This study was designed to estimate the prevalence of NA-related symptoms in a sample drawn from a general population and evaluate the role of aging. Subjects (1,100, mean age 41.9, SD 22.8 years) were randomly selected from the lists of seven general practitioners. A questionnaire on nighttime and morning NA-associated symptoms was used and frequency of occurrence was rated as never, so…

Effect of High-Frequency Oscillations on Cough Peak Flows Generated by Mechanical In-Exsufflation in Medically Stable Subjects With Amyotrophic Later…

2016

BACKGROUND: Mechanically assisted coughing with mechanical in-exsufflation (MI-E) is recommended for noninvasive management of respiratory secretions in amyotrophic lateral sclerosis (ALS). To improve the effectiveness of the technique, a new device combining MI-E with high-frequency oscillations (HFO) has been developed. This work aimed to assess the effect of HFO on the cough peak flow generated by MI-E in medically stable subjects with ALS. METHODS: This was a prospective study that included subjects with ALS in a medically stable condition. Cough peak flow generated by MI-E was measured in 4 situations: without HFO, with HFO during insufflation, with HFO during exsufflation, and with HF…

Quantitative analysis of airway obstruction in lymphangioleiomyomatosis

2020

Lymphangioleiomyomatosis (LAM) is a rare, cystic lung disease with progressive pulmonary function loss caused by progressively proliferating LAM cells. The degree of airway obstruction has not been well investigated within the pathogenesis of LAM. Using a combination of ex vivo computed tomography (CT), microCT and histology, the site and nature of airway obstruction in LAM explant lungs was compared with matched control lungs (n=5 each). The total number of airways per generation, total airway counts, terminal bronchioles number and surface density were compared in LAM versus control. Ex vivo CT analysis demonstrated a reduced number of airways from generation 7 on (p<0.0001) in LAM compar…

Clinical and Functional Characteristics of COPD Patients Across GOLD Classifications: Results of a Multicenter Observational Study.

2019

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease. The severity grading systems proposed by the Global initiative for Chronic Obstructive Lung Disease (GOLD) have changed over time. The aim of the study was to evaluate if the different GOLD classifications can capture the complexity of the disease by investigating the distribution of lung function and clinical parameters across the GOLD classification systems. This was an observational, retrospective, multicentre study. COPD patients were stratified according to the GOLD severity grading proposed in the 2007, and to the ABCD assessment tool present in the 2011, and 2017 versions of the initiative. Data from body plethy…

Tolerance of Volume Control Noninvasive Ventilation in Subjects With Amyotrophic Lateral Sclerosis.

2015

BACKGROUND: Noninvasive ventilation (NIV) tolerance has been identified as an independent predictor of survival in amyotrophic lateral sclerosis (ALS). Volume control continuous mandatory ventilation (VC-CMV) NIV has been associated with poor tolerance. The aim of this study was to determine the tolerance of subjects with ALS to VC-CMV NIV. METHODS: This was a prospective study involving subjects with ALS who were treated with VC-CMV NIV. Respiratory and functional parameters were recorded when the subjects began ventilatory support. NIV tolerance was evaluated after 3 months. RESULTS: Eighty-seven subjects with ALS were included. After 3 months, 80 subjects (92%) remained tolerant of NIV. …

Questionnaires, spirometry and PEF monitoring in epidemiological studies on elderly respiratory patients.

2003

Questionnaires are the most used subjective instrument of measurement in respiratory epidemiology. The standardisation of the questionnaires aims to limit bias by maximising validity and reliability, and comparability. Within the European Union project BIOMED1, a compendium of respiratory standard questionnaires (CORSQ) was developed for adults covering 18 topics from general information to early life events, through environmental risk factors and respiratory symptoms and diseases. Reliable spirometry data needs a rigorous quality control programme, as in the "Salute Respiratoria nell'Anziano" (Sa.R.A.) project, Italian for "Respiratory Health in the Elderly". Reproducibility rates were 95.…

Effect of Coronary Disease Characteristics on Prognostic Relevance of Residual Ischemia After Stent Implantation

2021

Objectives: We investigated the influence of coronary disease characteristics on prognostic implications of residual ischemia after coronary stent implantation.Methods: This study included 1,476 patients with drug-eluting stent implantation and available pre- and post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) measurements. Residual ischemia was defined as post-PCI FFR ≤ 0.80. Coronary disease characteristics with significant interaction hazard ratios (HRs) for clinical outcomes with residual ischemia were defined as interaction characteristics with residual ischemia (ICwRI). The primary outcome was target vessel failure (TVF)—a composite of cardiac death, target…