Effects of the use of multi-layer filter on radiation exposure and the quality of upper airway radiographs compared to the traditional copper filter.

PubMed

Klandima, Somphan; Kruatrachue, Anchalee; Wongtapradit, Lawan; Nithipanya, Narong; Ratanaprakarn, Warangkana

2014-06-01

The problem of image quality in a large number of upper airway obstructed patients is the superimposition of the airway over the bone of the spine on the AP view. This problem was resolved by increasing KVp to high KVp technique and adding extra radiographic filters (copper filter) to reduce the sharpness of the bone and increase the clarity of the airway. However, this raises a concern that patients might be receiving an unnecessarily higher dose of radiation, as well as the effectiveness of the invented filter compared to the traditional filter. To evaluate the level of radiation dose that patients receive with the use of multi-layer filter compared to non-filter and to evaluate the image quality of the upper airways between using the radiographic filter (multi-layer filter) and the traditional filter (copperfilter). The attenuation curve of both filter materials was first identified. Then, both the filters were tested with Alderson Rando phantom to determine the appropriate exposure. Using the method described, a new type of filter called the multi-layer filter for imaging patients was developed. A randomized control trial was then performed to compare the effectiveness of the newly developed multi-layer filter to the copper filter. The research was conducted in patients with upper airway obstruction treated at Queen Sirikit National Institute of Child Health from October 2006 to September 2007. A total of 132 patients were divided into two groups. The experimental group used high kVp technique with multi-layer filter, while the control group used copper filter. A comparison of film interpretation between the multi-layer filter and the copper filter was made by a number of radiologists who were blinded to both to the technique and type of filter used. Patients had less radiation from undergoing the kVp technique with copper filter and multi-layer filter compared to the conventional technique, where no filter is used. Patients received approximately 65.5% less

Composition of nasal airway surface liquid in cystic fibrosis and other airway diseases determined by X-ray microanalysis.

PubMed

Vanthanouvong, V; Kozlova, I; Johannesson, M; Nääs, E; Nordvall, S L; Dragomir, A; Roomans, G M

2006-04-01

The ionic composition of the airway surface liquid (ASL) in healthy individuals and in patients with cystic fibrosis (CF) has been debated. Ion transport properties of the upper airway epithelium are similar to those of the lower airways and it is easier to collect nasal ASL from the nose. ASL was collected with ion exchange beads, and the elemental composition of nasal fluid was determined by X-ray microanalysis in healthy subjects, CF patients, CF heterozygotes, patients with rhinitis, and with primary ciliary dyskinesia (PCD). In healthy subjects, the ionic concentrations were approximately isotonic. In CF patients, CF heterozygotes, rhinitis, and PCD patients, [Na] and [Cl] were significantly higher compared when compared with those in controls. [K] was significantly higher in CF and PCD patients compared with that in controls. Severely affected CF patients had higher ionic concentrations in their nasal ASL than in patients with mild or moderate symptoms. Female CF patients had higher levels of Na, Cl, and K than male patients. As higher salt concentrations in the ASL are also found in other patients with airway diseases involving chronic inflammation, it appears likely that inflammation-induced epithelial damage is important in determining the ionic composition of the ASL. Copyright (c) 2006 Wiley-Liss, Inc.

Pro-inflammatory mediators disrupt glucose homeostasis in airway surface liquid ‡

PubMed Central

Garnett, James P.; Nguyen, Trang T.; Moffatt, James D.; Pelham, Elizabeth R.; Kalsi, Kameljit K.; Baker, Emma H.; Baines, Deborah L.

2012-01-01

The glucose concentration of the airway surface liquid (ASL) is much lower than blood and is tightly regulated by the airway epithelium. ASL glucose is elevated in patients with viral colds, cystic fibrosis, chronic obstructive pulmonary disease (COPD) and asthma. Elevated ASL glucose is also associated with increased incidence of respiratory infection. However, the mechanism by which ASL glucose increases under inflammatory conditions is unknown. The aim of this study was to investigate the effect of pro-inflammatory mediators (PIMs) on the mechanisms governing airway glucose homeostasis in polarised monolayers of human airway (H441) and primary human bronchial epithelial (HBE) cells. Monolayers were treated with TNF-α, IFN-γ and LPS over 72 hours. PIM treatment led to increase in ASL glucose concentration and significantly reduced H441 and HBE transepithelial resistance (RT). This decline in RT was associated with an increase in paracellular permeability of glucose. Similar enhanced rates of paracellular glucose flux were also observed across excised trachea from LPS-treated mice. Interestingly, PIMs enhanced glucose uptake across the apical, but not the basolateral, membrane of H441 and HBE monolayers. This increase was predominantly via phloretin-sensitive GLUT-mediated uptake, which coincided with an increase in GLUT2 and GLUT10 abundance. In conclusion, exposure of airway epithelial monolayers to PIMs results in increased paracellular glucose flux, and apical GLUT-mediated glucose uptake. However uptake was insufficient to limit glucose accumulation in ASL. These data provide for the first time, a mechanism to support clinical findings that ASL glucose concentration is increased in patients with airway inflammation. PMID:22623330

Effects of Coal Fly Ash Particulate Matter on the Antimicrobial Activity of Airway Surface Liquid

PubMed Central

Vargas Buonfiglio, Luis G.; Mudunkotuwa, Imali A.; Abou Alaiwa, Mahmoud H.; Vanegas Calderón, Oriana G.; Borcherding, Jennifer A.; Gerke, Alicia K.; Zabner, Joseph; Grassian, Vicki H.

2017-01-01

Background: Sustained exposure to ambient particulate matter (PM) is a global cause of mortality. Coal fly ash (CFA) is a byproduct of coal combustion and is a source of anthropogenic PM with worldwide health relevance. The airway epithelia are lined with fluid called airway surface liquid (ASL), which contains antimicrobial proteins and peptides (AMPs). Cationic AMPs bind negatively charged bacteria to exert their antimicrobial activity. PM arriving in the airways could potentially interact with AMPs in the ASL to affect their antimicrobial activity. Objectives: We hypothesized that PM can interact with ASL AMPs to impair their antimicrobial activity. Methods: We exposed pig and human airway explants, pig and human ASL, and the human cationic AMPs β-defensin-3, LL-37, and lysozyme to CFA or control. Thereafter, we assessed the antimicrobial activity of exposed airway samples using both bioluminescence and standard colony-forming unit assays. We investigated PM-AMP electrostatic interaction by attenuated total reflection Fourier-transform infrared spectroscopy and measuring the zeta potential. We also studied the adsorption of AMPs on PM. Results: We found increased bacterial survival in CFA-exposed airway explants, ASL, and AMPs. In addition, we report that PM with a negative surface charge can adsorb cationic AMPs and form negative particle–protein complexes. Conclusion: We propose that when CFA arrives at the airway, it rapidly adsorbs AMPs and creates negative complexes, thereby decreasing the functional amount of AMPs capable of killing pathogens. These results provide a novel translational insight into an early mechanism for how ambient PM increases the susceptibility of the airways to bacterial infection. https://doi.org/10.1289/EHP876 PMID:28696208

Early cystic fibrosis lung disease: Role of airway surface dehydration and lessons from preventive rehydration therapies in mice.

PubMed

Mall, Marcus A; Graeber, Simon Y; Stahl, Mirjam; Zhou-Suckow, Zhe

2014-07-01

Cystic fibrosis (CF) lung disease starts in the first months of life and remains one of the most common fatal hereditary diseases. Early therapeutic interventions may provide an opportunity to prevent irreversible lung damage and improve outcome. Airway surface dehydration is a key disease mechanism in CF, however, its role in the in vivo pathogenesis and as therapeutic target in early lung disease remains poorly understood. Mice with airway-specific overexpression of the epithelial Na(+) channel (βENaC-Tg) recapitulate airway surface dehydration and phenocopy CF lung disease. Recent studies in neonatal βENaC-Tg mice demonstrated that airway surface dehydration produces early mucus plugging in the absence of mucus hypersecretion, which triggers airway inflammation, promotes bacterial infection and causes early mortality. Preventive rehydration therapy with hypertonic saline or amiloride effectively reduced mucus plugging and mortality in neonatal βENaC-Tg mice. These results support clinical testing of preventive/early rehydration strategies in infants and young children with CF. Copyright © 2014 Elsevier Ltd. All rights reserved.

In Vivo Airway Surface Liquid Cl− Analysis with Solid-State Electrodes

PubMed Central

Caldwell, Ray A.; Grubb, Barbara R.; Tarran, Robert; Boucher, Richard C.; Knowles, Michael R.; Barker, Pierre M.

2002-01-01

The pathogenesis of cystic fibrosis (CF) airways disease remains controversial. Hypotheses that link mutations in CFTR and defects in ion transport to CF lung disease predict that alterations in airway surface liquid (ASL) isotonic volume, or ion composition, are critically important. ASL [Cl−] is pivotal in discriminating between these hypotheses, but there is no consensus on this value given the difficulty in measuring [Cl−] in the “thin” ASL (∼30 μm) in vivo. Consequently, a miniaturized solid-state electrode with a shallow depth of immersion was constructed to measure ASL [Cl−] in vivo. In initial experiments, the electrode measured [Cl−] in physiologic salt solutions, small volume (7.6 μl) test solutions, and in in vitro cell culture models, with ≥93% accuracy. Based on discrepancies in reported values and/or absence of data, ASL Cl− measurements were made in the following airway regions and species. First, ASL [Cl−] was measured in normal human nasal cavity and averaged 117.3 ± 11.2 mM (n = 6). Second, ASL [Cl−] measured in large airway (tracheobronchial) regions were as follows: rabbit trachea and bronchus = 114.3 ± 1.8 mM; (n = 6) and 126.9 ± 1.7 mM; (n = 3), respectively; mouse trachea = 112.8 ± 4.2 mM (n = 13); and monkey bronchus = 112.3 ± 10.9 mM (n = 3). Third, Cl− measurements were made in small (1–2 mm) diameter airways of the rabbit (108.3 ± 7.1 mM, n = 5) and monkey (128.5 ± 6.8 mM, n = 3). The measured [Cl−], in excess of 100 mM throughout all airway regions tested in multiple species, is consistent with the isotonic volume hypothesis to describe ASL physiology. PMID:11773234

A Numerical Model of Viscoelastic Layer Entrainment by Airflow in Cough

NASA Astrophysics Data System (ADS)

Mitran, Sorin M.

2008-07-01

Coughing is an alternative mode of ensuring mucus clearance in the lung when normal cilia induced flow breaks down. A numerical model of this process is presented with the following aspects. (1) A portion of the airway comprising the first three bronchus generations is modeled as radially reinforced elastic tubes. Elasticity equations are solved to predict airway deformation under effect of airway pressure. (2) The compressible, turbulent flow induced by rapid lung contraction is modeled by direct numerical simulation for Reynolds numbers in the range 5,000-10,000 and by Large Eddy Simulation for Reynolds numbers in the range 5,000-40,000. (3) A two-layer model of the airway surface liquid (ASL) covering the airway epithelial layer is used. The periciliary liquid (PCL) in direct contact with the epithelial layer is considered to be a Newtonian fluid. Forces modeling cilia beating can act upon this layer. The mucus layer between the PCL and the interior airflow is modeled as an Oldroyd-B fluid. The overall computation is a fluid-structure interaction simulation that tracks changes in ASL thickness and airway diameters that result from impulsive airflow boundary conditions imposed at bronchi ends. In particular, the amount of mucus that is evacuated from the system is computed as a function of cough intensity and mucus rheological properties.

Secretory response induced by essential oils on airway surface fluid: a pharmacological MRI study.

PubMed

Nicolato, Elena; Boschi, Federico; Marzola, Pasquina; Sbarbati, Andrea

2009-07-30

Using pharmacological magnetic resonance imaging, we have performed an in vivo evaluation of the secretory response induced by essential oils in the rat airway. Aim of the work was to establish a computerized method to assess the efficacy of volatile compounds in spatially localized areas without the bias derived by subjective evaluation. Magnetic resonance experiments were carried out using a 4.7 T horizontal magnet. In the trachea, airway surface fluid was easily identified for its high intensity signal. The tracheal glands were also easily visible. The oesophageal lumen was usually collapsed and was identifiable only in the presence of intraluminal liquid. Scotch pine essential oil inhalation significantly increased the surface fluid in the middle portion of the trachea and the increase was visible at both 5 and 10 min. A lesser secretory response was detected after rosemary essential oil inhalation even though the response was significant with respect to the control in particular at 10 min. No secretory response was detected after peppermint essential oil inhalation both at 5 and 10 min. The data obtained in the present work demonstrate a chemically induced airway secretion. The availability of a pharmacological magnetic resonance imaging approach opens new perspectives to test the action of volatile compounds on the airway.

Investigation of mucus transport in an idealized lung airway model using multiphase CFD analysis

NASA Astrophysics Data System (ADS)

Rajendran, Rahul; Banerjee, Arindam

2015-11-01

Mucus, a Bingham fluid is transported in the pulmonary airways by consistent beating of the cilia and exhibits a wide range of physical properties in response to the core air flow and various pathological conditions. A better understanding of the interfacial instability is required as it plays a crucial role in gas transport, mixing, mucus clearance and drug delivery. In the current study, mucus is modelled as a Newtonian fluid and the two phase gas-liquid flow in the airways is investigated using an inhomogeneous Eulerian-Eulerian approach. The complex interface between the phases is tracked using the conventional VOF (Volume of Fluid) method. Results from our CFD simulations which are performed in idealized single and double bifurcation geometries will be presented and the influence of airflow rate, mucus layer thickness, mucus viscosity, airway geometry (branching & diameter) and surface tension on mucus flow behavior will be discussed. Mean mucus layer thickness, pressure drop due to momentum transfer & increased airway resistance, mucus transport speed and the flow morphology will be compared to existing experimental and theoretical data.

Airway surface liquid homeostasis in cystic fibrosis: pathophysiology and therapeutic targets.

PubMed

Haq, Iram J; Gray, Michael A; Garnett, James P; Ward, Christopher; Brodlie, Malcolm

2016-03-01

Cystic fibrosis (CF) is a life-limiting disease characterised by recurrent respiratory infections, inflammation and lung damage. The volume and composition of the airway surface liquid (ASL) are important in maintaining ciliary function, mucociliary clearance and antimicrobial properties of the airway. In CF, these homeostatic mechanisms are impaired, leading to a dehydrated and acidic ASL. ASL volume depletion in CF is secondary to defective anion transport by the abnormal cystic fibrosis transmembrane conductance regulator protein (CFTR). Abnormal CFTR mediated bicarbonate transport creates an unfavourable, acidic environment, which impairs antimicrobial function and alters mucus properties and clearance. These disease mechanisms create a disordered airway milieu, consisting of thick mucopurulent secretions and chronic bacterial infection. In addition to CFTR, there are additional ion channels and transporters in the apical airway epithelium that play a role in maintaining ASL homeostasis. These include the epithelial sodium channel (ENaC), the solute carrier 26A (SLC26A) family of anion exchangers, and calcium-activated chloride channels. In this review we discuss how the ASL is abnormal in CF and how targeting these alternative channels and transporters could provide an attractive therapeutic strategy to correct the underlying ASL abnormalities evident in CF. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Azithromycin ameliorates airway remodeling via inhibiting airway epithelium apoptosis.

PubMed

Liu, Yuanqi; Pu, Yue; Li, Diandian; Zhou, Liming; Wan, Lihong

2017-02-01

Azithromycin can benefit treating allergic airway inflammation and remodeling. In the present study, we hypothesized that azithromycin alleviated airway epithelium injury through inhibiting airway epithelium apoptosis via down regulation of caspase-3 and Bax/Bcl2 ratio in vivo and in vitro. Ovalbumin induced rat asthma model and TGF-β1-induced BEAS-2B cell apoptosis model were established, respectively. In vivo experiments, airway epithelium was stained with hematoxylin and eosin (HE) and periodic acid-Schiff (PAS) to histologically evaluate the airway inflammation and remodeling. Airway epithelium apoptotic index (AI) was further analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), while expression of apoptosis related gene (Bax, Bcl2, Caspase-3) in lungs were measured by qRT-PCR and western blotting, respectively. In vitro experiments, apoptosis were evaluated by Flow cytometry (FCM) and TUNEL. Above apoptosis related gene were also measured by qRT-PCR and western blotting. Compared with the OVA group, azithromycin significantly reduced the inflammation score, peribronchial smooth muscle layer thickness, epithelial thickening and goblet cell metaplasia (P<0.05), and effectively suppressed AI of airway epithelium (P<0.05). Moreover, the increasing mRNA and protein expressions of Caspase-3 and Bax/Bcl-2 ratio in lung tissue were all significantly decreased in azithromycin-treated rats (P<0.05). In vitro, azithromycin significantly suppressed TGF-β1-induced BEAS-2B cells apoptosis (P<0.05) and reversed TGF-β1 elevated Caspase-3 mRNA level and Bax/Bcl-2 ratio (P<0.05). Azithromycin is an attractive treatment option for reducing airway epithelial cell apoptosis by improving the imbalance of Bax/Bcl-2 ratio and inhibiting Caspase-3 level in airway epithelium. Copyright © 2016 Elsevier Inc. All rights reserved.

Measuring surface temperature and grading pathological changes of airway tissue in a canine model of inhalational thermal injury.

PubMed

Zhao, Ran; Di, La-na; Zhao, Xiao-zhuo; Wang, Cheng; Zhang, Guo-an

2013-06-01

Airway tissue shows unexpected invulnerability to heated air. The mechanisms of this phenomenon are open to debate. This study was designed to measure the surface temperatures at different locations of the airway, and to explore the relationship between the tissue's surface temperature and injury severity. Twenty dogs were randomly divided into four groups, including three experimental groups (six dogs in each) to inhale heated air at 70-80 °C (group I), 150-160 °C (group II) and 310-320 °C (group III) and a control group (two dogs, only for histological observation). Injury time was 20 min. Mucosal surface temperatures of the epiglottis (point A), cricoid cartilage (point B) and lower trachea (point C) were measured. Dogs in group I-III were divided into three subgroups (two in each), to be assayed at 12, 24 and 36 h after injury, respectively. For each dog, four tissue parts (epiglottis, larynx, lower trachea and terminal bronchiole) were microscopically observed and graded according to an original pathological scoring system (score range: 0-27). Surface temperatures of the airway mucosa increased slowly to 40.60±3.29 °C, and the highest peak temperature was 48.3 °C (group III, point A). The pathological score of burned tissues was 4.12±4.94 (0.0-18.0), suggesting slight to moderate injuries. Air temperature and airway location both influenced mucosal temperature and pathological scores very significantly, and there was a very significant positive correlation between tissue temperature and injury severity. Compared to the inhalational air hyperthermia, airway surface temperature was much lower, but was still positively correlated with thermal injury severity. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

Sialic acid-to-urea ratio as a measure of airway surface hydration

PubMed Central

Hill, David B.; Button, Brian; Shi, Shuai; Jania, Corey; Duncan, Elizabeth A.; Doerschuk, Claire M.; Chen, Gang; Ranganathan, Sarath; Stick, Stephen M.; Boucher, Richard C.

2017-01-01

Although airway mucus dehydration is key to pathophysiology of cystic fibrosis (CF) and other airways diseases, measuring mucus hydration is challenging. We explored a robust method to estimate mucus hydration using sialic acid as a marker for mucin content. Terminal sialic acid residues from mucins were cleaved by acid hydrolysis from airway samples, and concentrations of sialic acid, urea, and other biomarkers were analyzed by mass spectrometry. In mucins purified from human airway epithelial (HAE), sialic acid concentrations after acid hydrolysis correlated with mucin concentrations (r2 = 0.92). Sialic acid-to-urea ratios measured from filters applied to the apical surface of cultured HAE correlated to percent solids and were elevated in samples from CF HAEs relative to controls (2.2 ± 1.1 vs. 0.93 ± 1.8, P < 0.01). Sialic acid-to-urea ratios were elevated in bronchoalveolar lavage fluid (BALF) from β-epithelial sodium channel (ENaC) transgenic mice, known to have reduced mucus hydration, and mice sensitized to house dust mite allergen. In a translational application, elevated sialic acid-to-urea ratios were measured in BALF from young children with CF who had airway infection relative to those who did not (5.5 ± 3.7 vs. 1.9 ± 1.4, P < 0.02) and could be assessed simultaneously with established biomarkers of inflammation. The sialic acid-to-urea ratio performed similarly to percent solids, the gold standard measure of mucus hydration. The method proved robust and has potential to serve as flexible techniques to assess mucin hydration, particularly in samples like BALF in which established methods such as percent solids cannot be utilized. PMID:28062483

Elevated Airway Purines in COPD

PubMed Central

Lazaar, Aili L.; Bordonali, Elena; Qaqish, Bahjat; Boucher, Richard C.

2011-01-01

Background: Adenosine and related purines have established roles in inflammation, and elevated airway concentrations are predicted in patients with COPD. However, accurate airway surface purine measurements can be confounded by stimulation of purine release during collection of typical respiratory samples. Methods: Airway samples were collected noninvasively as exhaled breath condensate (EBC) from 36 healthy nonsmokers (NS group), 28 healthy smokers (S group), and 89 subjects with COPD (29 with GOLD [Global Initiative for Chronic Obstructive Lung Disease] stage II, 29 with GOLD stage III, and 31 with GOLD stage IV) and analyzed with mass spectrometry for adenosine, adenosine monophosphate (AMP), and phenylalanine, plus urea as a dilution marker. Variable dilution of airway secretions in EBC was controlled using ratios to urea, and airway surface concentrations were calculated using EBC to serum urea-based dilution factors. Results: EBC adenosine to urea ratios were similar in NS (0.20 ± 0.21) and S (0.22 ± 0.20) groups but elevated in those with COPD (0.32 ± 0.30, P < .01 vs NS). Adenosine to urea ratios were highest in the most severely affected cohort (GOLD IV, 0.35 ± 0.34, P < .01 vs NS) and negatively correlated with FEV1 (r = −0.27, P < .01). Elevated AMP to urea ratios were also observed in the COPD group (0.58 ± 0.97 COPD, 0.29 ± 0.35 NS, P < .02), but phenylalanine to urea ratios were similar in all groups. Airway surface adenosine concentrations calculated in a subset of subjects were 3.2 ± 2.7 μM in those with COPD (n = 28) relative to 1.7 ± 1.5 μM in the NS group (n = 16, P < .05). Conclusions: Airway purines are present on airway surfaces at physiologically significant concentrations, are elevated in COPD, and correlate with markers of COPD severity. Purinergic signaling pathways are potential therapeutic targets in COPD, and EBC purines are potential noninvasive biomarkers. PMID:21454402

Compliant layer chucking surface

DOEpatents

Blaedel, Kenneth L [Dublin, CA; Spence, Paul A [Pleasanton, CA; Thompson, Samuel L [Pleasanton, CA

2004-12-28

A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

Development of an airway mucus defect in the cystic fibrosis rat

PubMed Central

Birket, Susan E.; Davis, Joy M.; Fernandez, Courtney M.; Tuggle, Katherine L.; Oden, Ashley M.; Chu, Kengyeh K.; Tearney, Guillermo J.; Fanucchi, Michelle V.; Sorscher, Eric J.

2018-01-01

The mechanisms underlying the development and natural progression of the airway mucus defect in cystic fibrosis (CF) remain largely unclear. New animal models of CF, coupled with imaging using micro-optical coherence tomography, can lead to insights regarding these questions. The Cftr–/– (KO) rat allows for longitudinal examination of the development and progression of airway mucus abnormalities. The KO rat exhibits decreased periciliary depth, hyperacidic pH, and increased mucus solid content percentage; however, the transport rates and viscoelastic properties of the mucus are unaffected until the KO rat ages. Airway submucosal gland hypertrophy develops in the KO rat by 6 months of age. Only then does it induce increased mucus viscosity, collapse of the periciliary layer, and delayed mucociliary transport; stimulation of gland secretion potentiates this evolution. These findings could be reversed by bicarbonate repletion but not pH correction without counterion donation. These studies demonstrate that abnormal surface epithelium in CF does not cause delayed mucus transport in the absence of functional gland secretions. Furthermore, abnormal bicarbonate transport represents a specific target for restoring mucus clearance, independent of effects on periciliary collapse. Thus, mature airway secretions are required to manifest the CF defect primed by airway dehydration and bicarbonate deficiency. PMID:29321377

A pilot study of an in-vitro bovine trachea model of the effect of continuous positive airway pressure breathing on airway surface liquid.

PubMed

White, David E; Nates, Roy J; Bartley, Jim

2014-02-06

Continuous positive air pressure (CPAP) users frequently report troublesome symptoms of airway dryness and nasal congestion. Clinical investigations have demonstrated that supplementary humidification reduces these symptoms but the reason for their occurrence remains unexplained. Investigations using human computational air-conditioning models are unable to reproduce or quantify the apparent airway drying experienced during CPAP therapy. The purpose of this study was to determine whether augmented air pressures change overall mucosal airway surface liquid (ASL) water supply and, if so, the extent of this effect. In an original in vitro experimental set up, maximal ASL supply was determined in whole bovine trachea when exposed to simulated tidal breathing stresses over a range of air pressures. At ambient pressure, the maximal supply of ASL was found to compare well to previously published data (31.2 μl/cm2.hr). CPAP pressures from 5 cm H2O above ambient were found to reduce ASL supply by 22%. Statistical analysis (n = 8) showed a significant difference existed between the ambient and CPAP results (p < 0.0001), and that there was no significant variation between all pressurized results (p = 0.716). These findings provide preliminary data that ASL supply is reduced by CPAP therapy which may explain the airway drying symptoms associated with this therapy.

Cystic fibrosis swine fail to secrete airway surface liquid in response to inhalation of pathogens.

PubMed

Luan, Xiaojie; Belev, George; Tam, Julian S; Jagadeeshan, Santosh; Hassan, Noman; Gioino, Paula; Grishchenko, Nikolay; Huang, Yanyun; Carmalt, James L; Duke, Tanya; Jones, Teela; Monson, Bev; Burmester, Monique; Simovich, Tomer; Yilmaz, Orhan; Campanucci, Veronica A; Machen, Terry E; Chapman, L Dean; Ianowski, Juan P

2017-10-05

Cystic fibrosis is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) channel, which can result in chronic lung disease. The sequence of events leading to lung disease is not fully understood but recent data show that the critical pathogenic event is the loss of the ability to clear bacteria due to abnormal airway surface liquid secretion (ASL). However, whether the inhalation of bacteria triggers ASL secretion and whether this is abnormal in cystic fibrosis has never been tested. Here we show, using a novel synchrotron-based in vivo imaging technique, that wild-type pigs display both a basal and a Toll-like receptor-mediated ASL secretory response to the inhalation of cystic fibrosis relevant bacteria. Both mechanisms fail in CFTR -/- swine, suggesting that cystic fibrosis airways do not respond to inhaled pathogens, thus favoring infection and inflammation that may eventually lead to tissue remodeling and respiratory disease.Cystic fibrosis is caused by mutations in the CFTR chloride channel, leading to reduced airway surface liquid secretion. Here the authors show that exposure to bacteria triggers secretion in wild-type but not in pig models of cystic fibrosis, suggesting an impaired response to pathogens contributes to infection.

Dry deposition of pollutant and marker particles onto live mouse airway surfaces enhances monitoring of individual particle mucociliary transit behaviour.

PubMed

Donnelley, Martin; Morgan, Kaye S; Siu, Karen K W; Parsons, David W

2012-07-01

Particles suspended in the air are inhaled during normal respiration and unless cleared by airway defences, such as the mucociliary transit (MCT) system, they can remain and affect lung and airway health. Synchrotron phase-contrast X-ray imaging (PCXI) methods have been developed to non-invasively monitor the behaviour of individual particles in live mouse airways and in previous studies the MCT behaviour of particles and fibres in the airways of live mice after deposition in a saline carrier fluid have been examined. In this study a range of common respirable pollutant particles (lead dust, quarry dust and fibreglass fibres) as well as marker particles (hollow glass micro-spheres) were delivered into the trachea of live mice using a dry powder insufflator to more accurately mimic normal environmental particulate exposure and deposition via inhalation. The behaviour of the particles once delivered onto the airway surface was tracked over a five minute period via PCXI. All particles were visible after deposition. Fibreglass fibres remained stationary throughout while all other particle types transited the tracheal surface throughout the imaging period. In all cases the majority of the particle deposition and any airway surface activity was located close to the dorsal tracheal wall. Both the individual and bulk motions of the glass bead marker particles were visible and their behaviour enabled otherwise hidden MCT patterns to be revealed. This study verified the value of PCXI for examining the post-deposition particulate MCT behaviour in the mouse trachea and highlighted that MCT is not a uniform process as suggested by radiolabel studies. It also directly revealed the advantages of dry particle delivery for establishing adequate particulate presence for visualizing MCT behaviour. The MCT behaviour and rate seen after dry particle delivery was different from that in previous carrier-fluid studies. It is proposed that dry particle delivery is essential for producing

Acoustic Tomography of the Atmospheric Surface Layer

DTIC Science & Technology

2014-11-28

Report Title Acoustic tomography of the atmospheric surface layer (ASL) is based on the measurements of the travel times of sound propagation between...SECURITY CLASSIFICATION OF: Acoustic tomography of the atmospheric surface layer (ASL) is based on the measurements of the travel times of sound ...organ. In the case of acoustic tomography of the atmospheric surface layer (ASL), the travel times of sound propagation between speakers and

ELLIPSOMETRY OF ELECTROCHEMICAL SURFACE LAYERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muller, R.H.

1977-06-01

Ellipsometry is concerned with the analysis and interpretation of changes in the state of polarization caused by reflection. The technique has found increasing interest in recent years for the measurement of thin films because it is unusually sensitive, disturbs the object minimally and can be applied to surfaces contained in any optically transparent medium. Film thicknesses amenable to measurement range from fractional monoatomic coverage to microscopic thicknesses. The measurement of changes in the state of polarization of light due to reflection provides an unusually sensitive tool for observing surface layers in any optically transparent environment. A fast, self-compensating ellipsometer hasmore » been used to observe the electrochemical formation of reacted surface layers. The optical effect of mass-transport boundary layers and component imperfections have been taken into account in the interpretation of results.« less

Organic light emitting diode with surface modification layer

DOEpatents

Basil, John D.; Bhandari, Abhinav; Buhay, Harry; Arbab, Mehran; Marietti, Gary J.

2017-09-12

An organic light emitting diode (10) includes a substrate (12) having a first surface (14) and a second surface (16), a first electrode (32), and a second electrode (38). An emissive layer (36) is located between the first electrode (32) and the second electrode (38). The organic light emitting diode (10) further includes a surface modification layer (18). The surface modification layer (18) includes a non-planar surface (30, 52).

Improved Modeling of Surface Layer Parameters in a AGCM Using Refined Vertical Resolution in the Surface Layer

NASA Astrophysics Data System (ADS)

Shin, H. H.; Zhao, M.; Ming, Y.; Chen, X.; Lin, S. J.

2017-12-01

Surface layer (SL) parameters in atmospheric models - such as 2-m air temperature (T2), 10-m wind speed (U10), and surface turbulent fluxes - are computed by applying the Monin-Obukhov Similarity Theory (MOST) to the lowest model level height (LMH) in the models. The underlying assumption is that LMH is within surface layer height (SLH), but most AGCMs hardly meet the condition in stable boundary layers (SBLs) over land. To assess the errors in modeled SL parameters caused by this, offline computations of the MOST are performed with different LMHs from 1 to 100 m, for an idealized SBL case with prescribed surface parameters (surface temperature, roughness length and Obukhov length), and vertical profiles of temperature and winds. The results show that when LMH is higher than SLH, T2 and U10 are underestimated by O(1 K) and O(1 m/s), respectively, and the biases increase as LMH increases. Based on this, the refined vertical resolution with an additional layer in the SL is applied to the GFDL AGCM, and it reduces the systematic cold biases in T2 and the systematic underestimation of U10.

Observation of surface layering in a nonmetallic liquid

NASA Astrophysics Data System (ADS)

Mo, Haiding; Evmenenko, Guennadi; Kewalramani, Sumit; Kim, Kyungil; Dutta, Pulak; Ehrlich, Steven

2006-03-01

Non-monotonic density profiles (layers) have previously been observed at the free surfaces of many metallic liquids, but not in isotropic dielectric liquids. Whether the presence of an electron gas is necessary for surface layering has been the subject of debate. Until recently, MD simulations have suggested that layering at free liquid interface may be a generic phenomenon and is not limited to the metallic liquids^1. The theories predict that if normal liquids can be cooled down to temperatures low enough, layering structure should be observed experimentally. However, this is difficult for most molecular liquids because these liquids freeze well above the temperature necessary for observing the layering structure. By studying the surface structure of liquid TEHOS (tetrakis(2-ethylhexoxy)silane), which combines relatively low freezing point and high boiling point compared to that of most molecular liquids, we have observed the evidence of layering at the free interface of liquid TEHOS using x-ray reflectivity. When cooled to T/Tc 0.25 (well above the bulk freezing point, Tc is the critical temperature of TEHOS), the surface roughness drops sharply and density oscillations appear near the surface. Lateral ordering of the surface layers is liquid-like, just as at liquid metal surfaces. 1. E. Chac'on and P. Tarazona, Phys. Rev. Lett. 91 166103-1 (2003)

Assessment of surface turbulent fluxes using geostationary satellite surface skin temperatures and a mixed layer planetary boundary layer scheme

NASA Technical Reports Server (NTRS)

Diak, George R.; Stewart, Tod R.

1989-01-01

A method is presented for evaluating the fluxes of sensible and latent heating at the land surface, using satellite-measured surface temperature changes in a composite surface layer-mixed layer representation of the planetary boundary layer. The basic prognostic model is tested by comparison with synoptic station information at sites where surface evaporation climatology is well known. The remote sensing version of the model, using satellite-measured surface temperature changes, is then used to quantify the sharp spatial gradient in surface heating/evaporation across the central United States. An error analysis indicates that perhaps five levels of evaporation are recognizable by these methods and that the chief cause of error is the interaction of errors in the measurement of surface temperature change with errors in the assigment of surface roughness character. Finally, two new potential methods for remote sensing of the land-surface energy balance are suggested which will relay on space-borne instrumentation planned for the 1990s.

Discrete cilia modelling with singularity distributions: application to the embryonic node and the airway surface liquid.

PubMed

Smith, D J; Gaffney, E A; Blake, J R

2007-07-01

We discuss in detail techniques for modelling flows due to finite and infinite arrays of beating cilia. An efficient technique, based on concepts from previous 'singularity models' is described, that is accurate in both near and far-fields. Cilia are modelled as curved slender ellipsoidal bodies by distributing Stokeslet and potential source dipole singularities along their centrelines, leading to an integral equation that can be solved using a simple and efficient discretisation. The computed velocity on the cilium surface is found to compare favourably with the boundary condition. We then present results for two topics of current interest in biology. 1) We present the first theoretical results showing the mechanism by which rotating embryonic nodal cilia produce a leftward flow by a 'posterior tilt,' and track particle motion in an array of three simulated nodal cilia. We find that, contrary to recent suggestions, there is no continuous layer of negative fluid transport close to the ciliated boundary. The mean leftward particle transport is found to be just over 1 mum/s, within experimentally measured ranges. We also discuss the accuracy of models that represent the action of cilia by steady rotlet arrays, in particular, confirming the importance of image systems in the boundary in establishing the far-field fluid transport. Future modelling may lead to understanding of the mechanisms by which morphogen gradients or mechanosensing cilia convert a directional flow to asymmetric gene expression. 2) We develop a more complex and detailed model of flow patterns in the periciliary layer of the airway surface liquid. Our results confirm that shear flow of the mucous layer drives a significant volume of periciliary liquid in the direction of mucus transport even during the recovery stroke of the cilia. Finally, we discuss the advantages and disadvantages of the singularity technique and outline future theoretical and experimental developments required to apply this

Laser modification of macroscopic properties of metal surface layer

NASA Astrophysics Data System (ADS)

Kostrubiec, Franciszek

1995-03-01

Surface laser treatment of metals comprises a number of diversified technological operations out of which the following can be considered the most common: oxidation and rendering surfaces amorphous, surface hardening of steel, modification of selected physical properties of metal surface layers. In the paper basic results of laser treatment of a group of metals used as base materials for electric contacts have been presented. The aim of the study was to test the usability of laser treatment from the viewpoint of requirements imposed on materials for electric contacts. The results presented in the paper refer to two different surface treatment technologies: (1) modification of infusible metal surface layer: tungsten and molybdenum through laser fusing of their surface layer and its crystallization, and (2) modification of surface layer properties of other metals through laser doping of their surface layer with foreign elements. In the paper a number of results of experimental investigations obtained by the team under the author's supervision are presented.

Uptake and transport of B12-conjugated nanoparticles in airway epithelium☆

PubMed Central

Fowler, Robyn; Vllasaliu, Driton; Falcone, Franco H.; Garnett, Martin; Smith, Bryan; Horsley, Helen; Alexander, Cameron; Stolnik, Snow

2013-01-01

Non-invasive delivery of biotherapeutics, as an attractive alternative to injections, could potentially be achieved through the mucosal surfaces, utilizing nanoscale therapeutic carriers. However, nanoparticles do not readily cross the mucosal barriers, with the epithelium presenting a major barrier to their translocation. The transcytotic pathway of vitamin B12 has previously been shown to ‘ferry’ B12-decorated nanoparticles across intestinal epithelial (Caco-2) cells. However, such studies have not been reported for the airway epithelium. Furthermore, the presence in the airways of the cell machinery responsible for transepithelial trafficking of B12 is not widely reported. Using a combination of molecular biology and immunostaining techniques, our work demonstrates that the bronchial cell line, Calu-3, expresses the B12-intrinsic factor receptor, the transcobalamin II receptor and the transcobalamin II carrier protein. Importantly, the work showed that sub-200 nm model nanoparticles chemically conjugated to B12 were internalised and transported across the Calu-3 cell layers, with B12 conjugation not only enhancing cell uptake and transepithelial transport, but also influencing intracellular trafficking. Our work therefore demonstrates that the B12 endocytotic apparatus is not only present in this airway model, but also transports ligand-conjugated nanoparticles across polarised epithelial cells, indicating potential for B12-mediated delivery of nanoscale carriers of biotherapeutics across the airways. PMID:24008152

Surface Characterization of an Organized Titanium Dioxide Layer

NASA Astrophysics Data System (ADS)

Curtis, Travis

Soft lithographic printing techniques can be used to control the surface morphology of titanium dioxide layers on length scales of several hundred nanometers. Controlling surface morphology and volumetric organization of titanium dioxide electrodes can potentially be used in dye-sensitized solar cell devices. This thesis explores how layer-by-layer replication can lead to well defined, dimensionally controlled volumes and details how these control mechanisms influence surface characteristics of the semiconducting oxide.

Effects of maternal folic acid supplementation on airway remodeling and allergic airway disease development.

PubMed

İscan, Burcin; Tuzun, Funda; Eroglu Filibeli, Berna; Cilekar Micili, Serap; Ergur, Bekir Ugur; Duman, Nuray; Ozkan, Hasan; Kumral, Abdullah

2018-03-27

Maternal folic acid supplementation has been recommended prior to and during the first trimester of pregnancy to reduce the risk of infant neural tube defects. However, an uncertain relationship between folic acid supplementation during pregnancy and development of childhood asthma exists. Recent data show a methyl donor-rich diet could increase the risk of developing allergic airway disease through DNA methylation and aberrant gene transcription. This study evaluated the effect of folic acid supplementation during pregnancy on airway remodeling and allergic airway disease vulnerability in a mouse asthma model. BALB/c mice were divided into four groups according to gestational folic acid supplementation and postnatal ovalbumin (OVA) exposure: Group 1 (whole pregnancy folic acid supplementation + OVA-exposed group), Group 2 (first gestational week folic acid supplementation + OVA-exposed group), Group 3 (no folic acid supplementation + OVA-exposed group), and Group 4 (control group). Offspring were sacrificed on day 45 for immunohistological and ultrastructural tests. In OVA challenged groups, folic acid supplementation led to a thicker epithelial and subepithelial smooth muscle layer than in the unsupplemented group. Moreover, folic acid supplementation during whole pregnancy (Group 1) was associated with a thicker epithelial and subepithelial smooth muscle layer than folic acid supplementation during the first week of pregnancy (Group 2), suggesting a duration-response relationship. Electron microscopic imaging revealed that structural changes including the loss of epithelial integrity, thickening of basement membrane, and subepithelial fibrosis were more prominent in the folic acid supplementation groups. This study suggested that maternal folic acid supplementation during pregnancy affects airway remodeling and increases the allergic responses induced by ovalbumin challenge in offspring. In addition, the effect size increased as the duration and

Differential effects of cyclic and constant stress on ATP release and mucociliary transport by human airway epithelia

PubMed Central

Button, Brian; Picher, Maryse; Boucher, Richard C

2007-01-01

In the lungs, the first line of defence against bacterial infection is the thin layer of airway surface liquid (ASL) lining the airway surface. The superficial airway epithelium exhibits complex regulatory pathways that blend ion transport to adjust ASL volume to maintain proper mucociliary clearance (MCC). We hypothesized that stresses generated by airflow and transmural pressures during breathing govern ASL volume by regulating the rate of epithelial ATP release. Luminal ATP, via interactions with apical membrane P2-purinoceptors, regulates the balance of active ion secretion versus absorption to maintain ASL volume at optimal levels for MCC. In this study we tested the hypothesis that cyclic compressive stress (CCS), mimicking normal tidal breathing, regulates ASL volume in airway epithelia. Polarized tracheobronchial epithelial cultures from normal and cystic fibrosis (CF) subjects responded to a range of CCS by increasing the rate of ATP release. In normal airway epithelia, the CCS-induced increase in ASL ATP concentration was sufficient to induce purinoceptor-mediated increases in ASL height and MCC, via inhibition of epithelial Na+-channel-mediated Na+ absorption and stimulation of Cl− secretion through CFTR and the Ca2+-activated chloride channels. In contrast, static, non-oscillatory stress did not stimulate ATP release, ion transport or MCC, emphasizing the importance of rhythmic mechanical stress for airway defence. In CF airway cultures, which exhibit basal ASL depletion, CCS was partially effective, producing less ASL volume secretion than in normal cultures, but a level sufficient to restore MCC. The present data suggest that CCS may (1) regulate ASL volume in the normal lung and (2) improve clearance in the lungs of CF patients, potentially explaining the beneficial role of exercise in lung defence. PMID:17317749

Boundary Layer Flow Over a Moving Wavy Surface

NASA Astrophysics Data System (ADS)

Hendin, Gali; Toledo, Yaron

2016-04-01

Boundary Layer Flow Over a Moving Wavy Surface Gali Hendin(1), Yaron Toledo(1) January 13, 2016 (1)School of Mechanical Engineering, Tel-Aviv University, Israel Understanding the boundary layer flow over surface gravity waves is of great importance as various atmosphere-ocean processes are essentially coupled through these waves. Nevertheless, there are still significant gaps in our understanding of this complex flow behaviour. The present work investigates the fundamentals of the boundary layer air flow over progressive, small-amplitude waves. It aims to extend the well-known Blasius solution for a boundary layer over a flat plate to one over a moving wavy surface. The current analysis pro- claims the importance of the small curvature and the time-dependency as second order effects, with a meaningful impact on the similarity pattern in the first order. The air flow over the ocean surface is modelled using an outer, inviscid half-infinite flow, overlaying the viscous boundary layer above the wavy surface. The assumption of a uniform flow in the outer layer, used in former studies, is now replaced with a precise analytical solution of the potential flow over a moving wavy surface with a known celerity, wavelength and amplitude. This results in a conceptual change from former models as it shows that the pressure variations within the boundary layer cannot be neglected. In the boundary layer, time-dependent Navier-Stokes equations are formulated in a curvilinear, orthogonal coordinate system. The formulation is done in an elaborate way that presents additional, formerly neglected first-order effects, resulting from the time-varying coordinate system. The suggested time-dependent curvilinear orthogonal coordinate system introduces a platform that can also support the formulation of turbulent problems for any surface shape. In order to produce a self-similar Blasius-type solution, a small wave-steepness is assumed and a perturbation method is applied. Consequently, a

Estimating in vivo airway surface liquid concentration in trials of inhaled antibiotics.

PubMed

Hasan, M A; Lange, C F

2007-01-01

Antibiotic drugs exhibit concentration dependence in their efficacy. Therefore, ensuring appropriate concentration of these drugs in the relevant body fluid is important for obtaining the desired therapeutic and physiological action. Until recently there had been no suitable method available to measure or estimate concentration of drugs in the human airways resulting from inhaled aerosols or to determine the amount of inhaled antibiotics required to ensure minimum inhibitory concentration of a drug in the airway surface liquid (ASL). In this paper a numerical method is used for estimating local concentration of inhaled pharmaceutical aerosols in different generations of the human tracheobronchial airways. The method utilizes a mathematical lung deposition model to estimate amounts of aerosols depositing in different lung generations, and a recent ASL model along with deposition results to assess the concentration of deposited drugs immediately following inhalation. Examples of concentration estimates for two case studies: one for the antibiotic tobramycin against Pseudomonas aeruginosa, and another for taurolidine against Burkholderia cepacia are presented. The aerosol characteristics, breathing pattern and properties of nebulized solutions were adopted from two recent clinical studies on efficacy of these drugs in cystic fibrosis (CF) patients and from other sources in the literature. While the clinically effective tobramycin showed a concentration higher than the required in vivo concentration, that for the ineffective taurolidine was found to be below the speculated required in vivo concentration. Results of this study thus show that the mathematical ASL model combined with the lung deposition model can be an effective tool for helping decide the optimum dosage of inhaled antibiotic drugs delivered during human clinical trials.

Generation and characterization of surface layers on acoustically levitated drops.

PubMed

Tuckermann, Rudolf; Bauerecker, Sigurd; Cammenga, Heiko K

2007-06-15

Surface layers of natural and technical amphiphiles, e.g., octadecanol, stearic acid and related compounds as well as perfluorinated fatty alcohols (PFA), have been investigated on the surface of acoustically levitated drops. In contrast to Langmuir troughs, traditionally used in the research of surface layers at the air-water interface, acoustic levitation offers the advantages of a minimized and contact-less technique. Although the film pressure cannot be directly adjusted on acoustically levitated drops, it runs through a wide pressure range due to the shrinking surface of an evaporating drop. During this process, different states of the generated surface layer have been identified, in particular the phase transition from the gaseous or liquid-expanded to the liquid-condensed state of surface layers of octadecanol and other related amphiphiles. Characteristic parameters, such as the relative permeation resistance and the area per molecule in a condensed surface layer, have been quantified and were found comparable to results obtained from surface layers generated on Langmuir troughs.

Different Conformations of Surface Cellulose Molecules in Native Cellulose Microfibrils Revealed by Layer-by-Layer Peeling.

PubMed

Funahashi, Ryunosuke; Okita, Yusuke; Hondo, Hiromasa; Zhao, Mengchen; Saito, Tsuguyuki; Isogai, Akira

2017-11-13

Layer-by-layer peeling of surface molecules of native cellulose microfibrils was performed using a repeated sequential process of 2,2,6,6-tetramethylpiperidine-1-oxyl radical-mediated oxidation followed by hot alkali extraction. Both highly crystalline algal and tunicate celluloses and low-crystalline cotton and wood celluloses were investigated. Initially, the C6-hydroxy groups of the outermost surface molecules of each algal cellulose microfibril facing the exterior had the gauche-gauche (gg) conformation, whereas those facing the interior had the gauche-trans (gt) conformation. All the other C6-hydroxy groups of the cellulose molecules inside the microfibrils contributing to crystalline cellulose I had the trans-gauche (tg) conformation. After surface peeling, the originally second-layer molecules from the microfibril surface became the outermost surface molecules, and the original tg conformation changed to gg and gt conformations. The plant cellulose microfibrils likely had disordered structures for both the outermost surface and second-layer molecules, as demonstrated using the same layer-by-layer peeling technique.

Acidic pH increases airway surface liquid viscosity in cystic fibrosis

PubMed Central

Tang, Xiao Xiao; Ostedgaard, Lynda S.; Hoegger, Mark J.; Moninger, Thomas O.; Karp, Philip H.; McMenimen, James D.; Choudhury, Biswa; Varki, Ajit; Stoltz, David A.; Welsh, Michael J.

2016-01-01

Cystic fibrosis (CF) disrupts respiratory host defenses, allowing bacterial infection, inflammation, and mucus accumulation to progressively destroy the lungs. Our previous studies revealed that mucus with abnormal behavior impaired mucociliary transport in newborn CF piglets prior to the onset of secondary manifestations. To further investigate mucus abnormalities, here we studied airway surface liquid (ASL) collected from newborn piglets and ASL on cultured airway epithelia. Fluorescence recovery after photobleaching revealed that the viscosity of CF ASL was increased relative to that of non-CF ASL. CF ASL had a reduced pH, which was necessary and sufficient for genotype-dependent viscosity differences. The increased viscosity of CF ASL was not explained by pH-independent changes in HCO3– concentration, altered glycosylation, additional pH-induced disulfide bond formation, increased percentage of nonvolatile material, or increased sulfation. Treating acidic ASL with hypertonic saline or heparin largely reversed the increased viscosity, suggesting that acidic pH influences mucin electrostatic interactions. These findings link loss of cystic fibrosis transmembrane conductance regulator–dependent alkalinization to abnormal CF ASL. In addition, we found that increasing Ca2+ concentrations elevated ASL viscosity, in part, independently of pH. The results suggest that increasing pH, reducing Ca2+ concentration, and/or altering electrostatic interactions in ASL might benefit early CF. PMID:26808501

Atomic and molecular layer deposition for surface modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi; Sievänen, Jenni; Salo, Erkki

2014-06-01

Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjetmore » printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al{sub 2}O{sub 3} due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO{sub 2}. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt.« less

Electron Scattering at Surfaces of Epitaxial Metal Layers

NASA Astrophysics Data System (ADS)

Chawla, Jasmeet Singh

In the field of electron transport in metal films and wires, the 'size effect' refers to the increase in the resistivity of the films and wires as their critical dimensions (thickness of film, width and height of wires) approach or become less than the electron mean free path lambda, which is, for example, 39 nm for bulk copper at room temperature. This size-effect is currently of great concern to the semiconductor industry because the continued downscaling of feature sizes has already lead to Cu interconnect wires in this size effect regime, with a reported 2.5 times higher resistivity for 40 nm wide Cu wires than for bulk Cu. Silver is a possible alternate material for interconnect wires and titanium nitride is proposed as a gate metal in novel field-effect-transistors. Therefore, it is important to develop an understanding of how the growth, the surface morphology, and the microstructure of ultrathin (few nanometers) Cu, Ag and TiN layers affect their electrical properties. This dissertation aims to advance the scientific knowledge of electron scattering at surfaces (external surfaces and grain boundaries), that are, the primary reasons for the size-effect in metal conductors. The effect of surface and grain boundary scattering on the resistivity of Cu thin films and nanowires is separately quantified using (i) in situ transport measurements on single-crystal, atomically smooth Cu(001) layers, (ii) textured polycrystalline Cu(111) layers and patterned wires with independently varying grain size, thickness and line width, and (iii) in situ grown interfaces including Cu-Ta, Cu-MgO, Cu-vacuum and Cu-oxygen. In addition, the electron surface scattering is also measured in situ for single-crystal Ag(001), (111) twinned epitaxial Ag(001), and single-crystal TiN(001) layers. Cu(001), Ag(001), and TiN(001) layers with a minimum continuous thickness of 4, 3.5 and 1.8 nm, respectively, are grown by ultra-high vacuum magnetron sputter deposition on MgO(001) substrates with

Enrichment and association of lead and bacteria at particulate surfaces in a salt-marsh surface layer

USGS Publications Warehouse

Harvey, R.W.; Lion, Leonard W.; Young, L.Y.; Leckie, J.O.

1982-01-01

The particle-laden surface layer (approx 150-370 mu m) and subsurface waters of a South San Francisco Bay salt marsh were sampled over 2 tidal cycles and analyzed for particle numbers and particulate-associated and total concentrations of Pb and bacteria. Laboratory studies examined the ability of a bacterial isolate from the surface layer and a bacterial 'film-former' to sorb Pb at environmentally significant concentrations in seawater. Degrees by which Pb concentrated in the surface layer relative to the subsurface strongly correlated with enrichments of surface layer bacteria (bacterioneuston). A significant fraction of the bacterioneuston and surface layer Pb were associated with particles. Particle-bound bacterioneuston may interact with Pb at particulate surfaces in this microenvironment.

Improve oxidation resistance at high temperature by nanocrystalline surface layer

NASA Astrophysics Data System (ADS)

Xia, Z. X.; Zhang, C.; Huang, X. F.; Liu, W. B.; Yang, Z. G.

2015-08-01

An interesting change of scale sequence occurred during oxidation of nanocrystalline surface layer by means of a surface mechanical attrition treatment. The three-layer oxide structure from the surface towards the matrix is Fe3O4, spinel FeCr2O4 and corundum (Fe,Cr)2O3, which is different from the typical two-layer scale consisted of an Fe3O4 outer layer and an FeCr2O4 inner layer in conventional P91 steel. The diffusivity of Cr, Fe and O is enhanced concurrently in the nanocrystalline surface layer, which causes the fast oxidation in the initial oxidation stage. The formation of (Fe,Cr)2O3 inner layer would inhabit fast diffusion of alloy elements in the nanocrystalline surface layer of P91 steel in the later oxidation stage, and it causes a decrease in the parabolic oxidation rate compared with conventional specimens. This study provides a novel approach to improve the oxidation resistance of heat resistant steel without changing its Cr content.

Real-time non-invasive detection of inhalable particulates delivered into live mouse airways.

PubMed

Donnelley, Martin; Morgan, Kaye S; Fouras, Andreas; Skinner, William; Uesugi, Kentaro; Yagi, Naoto; Siu, Karen K W; Parsons, David W

2009-07-01

Fine non-biological particles small enough to be suspended in the air are continually inhaled as we breathe. These particles deposit on airway surfaces where they are either cleared by airway defences or can remain and affect lung health. Pollutant particles from vehicles, building processes and mineral and industrial dusts have the potential to cause both immediate and delayed health problems. Because of their small size, it has not been possible to non-invasively examine how individual particles deposit on live airways, or to consider how they behave on the airway surface after deposition. In this study, synchrotron phase-contrast X-ray imaging (PCXI) has been utilized to detect and monitor individual particle deposition. The in vitro detectability of a range of potentially respirable particulates was first determined. Of the particulates tested, only asbestos, quarry dust, fibreglass and galena (lead sulfate) were visible in vitro. These particulates were then examined after delivery into the nasal airway of live anaesthetized mice; all were detectable in vivo but each exhibited different surface appearances and behaviour along the airway surface. The two fibrous particulates appeared as agglomerations enveloped by fluid, while the non-fibrous particulates were present as individual particles. Synchrotron PCXI provides the unique ability to non-invasively detect and track deposition of individual particulates in live mouse airways. With further refinement of particulate sizing and delivery techniques, PCXI should provide a novel approach for live animal monitoring of airway particulates relevant to lung health.

Ocean haline skin layer and turbulent surface convections

NASA Astrophysics Data System (ADS)

Zhang, Y.; Zhang, X.

2012-04-01

The ocean haline skin layer is of great interest to oceanographic applications, while its attribute is still subject to considerable uncertainty due to observational difficulties. By introducing Batchelor micro-scale, a turbulent surface convection model is developed to determine the depths of various ocean skin layers with same model parameters. These parameters are derived from matching cool skin layer observations. Global distributions of salinity difference across ocean haline layers are then simulated, using surface forcing data mainly from OAFlux project and ISCCP. It is found that, even though both thickness of the haline layer and salinity increment across are greater than the early global simulations, the microwave remote sensing error caused by the haline microlayer effect is still smaller than that from other geophysical error sources. It is shown that forced convections due to sea surface wind stress are dominant over free convections driven by surface cooling in most regions of oceans. The free convection instability is largely controlled by cool skin effect for the thermal microlayer is much thicker and becomes unstable much earlier than the haline microlayer. The similarity of the global distributions of temperature difference and salinity difference across cool and haline skin layers is investigated by comparing their forcing fields of heat fluxes. The turbulent convection model is also found applicable to formulating gas transfer velocity at low wind.

Characterization and use of crystalline bacterial cell surface layers

NASA Astrophysics Data System (ADS)

Sleytr, Uwe B.; Sára, Margit; Pum, Dietmar; Schuster, Bernhard

2001-10-01

Crystalline bacterial cell surface layers (S-layers) are one of the most common outermost cell envelope components of prokaryotic organisms (archaea and bacteria). S-layers are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membranes developed during evolution. S-layers as the most abundant of prokaryotic cellular proteins are appealing model systems for studying the structure, synthesis, genetics, assembly and function of proteinaceous supramolecular structures. The wealth of information existing on the general principle of S-layers have revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for chemical modifications and binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from a variety of organisms are capable of recrystallizing as closed monolayers onto solid supports (e.g., metals, polymers, silicon wafers) at the air-water interface, on lipid films or onto the surface of liposomes; (iv) functional domains can be incorporated in S-layer proteins by genetic engineering. Thus, S-layer technologies particularly provide new approaches for biotechnology, biomimetics, molecular nanotechnology, nanopatterning of surfaces and formation of ordered arrays of metal clusters or nanoparticles as required for nanoelectronics.

Turbulent boundary layer on a convex, curved surface

NASA Technical Reports Server (NTRS)

Gillis, J. C.; Johnston, J. P.; Kays, W. M.; Moffat, R. J.

1980-01-01

The effects of strong convex curvature on boundary layer turbulence were investigated. The data gathered on the behavior of Reynolds stress suggested the formulation of a simple turbulence model. Three sets of data were taken on two separate facilities. Both rigs had flow from a flat surface, over a convex surface with 90 deg of turning, and then onto a flat recovery surface. The geometry was adjusted so that, for both rigs, the pressure gradient along the test surface was zero - thus avoiding any effects of streamwise acceleration on the wall layers. Results show that after a sudden introduction of curvature, the shear stress in the outer part of the boundary layer is sharply diminished and is even slightly negative near the edge. The wall shear also drops off quickly downstream. In contrast, when the surface suddenly becomes flat again, the wall shear and shear stress profiles recover very slowly towards flat wall conditions.

Preservation of Archaeal Surface Layer Structure During Mineralization

NASA Astrophysics Data System (ADS)

Kish, Adrienne; Miot, Jennyfer; Lombard, Carine; Guigner, Jean-Michel; Bernard, Sylvain; Zirah, Séverine; Guyot, François

2016-05-01

Proteinaceous surface layers (S-layers) are highly ordered, crystalline structures commonly found in prokaryotic cell envelopes that augment their structural stability and modify interactions with metals in the environment. While mineral formation associated with S-layers has previously been noted, the mechanisms were unconstrained. Using Sulfolobus acidocaldarius a hyperthermophilic archaeon native to metal-enriched environments and possessing a cell envelope composed only of a S-layer and a lipid cell membrane, we describe a passive process of iron phosphate nucleation and growth within the S-layer of cells and cell-free S-layer “ghosts” during incubation in a Fe-rich medium, independently of metabolic activity. This process followed five steps: (1) initial formation of mineral patches associated with S-layer; (2) patch expansion; (3) patch connection; (4) formation of a continuous mineral encrusted layer at the cell surface; (5) early stages of S-layer fossilization via growth of the extracellular mineralized layer and the mineralization of cytosolic face of the cell membrane. At more advanced stages of encrustation, encrusted outer membrane vesicles are formed, likely in an attempt to remove damaged S-layer proteins. The S-layer structure remains strikingly well preserved even upon the final step of encrustation, offering potential biosignatures to be looked for in the fossil record.

A biomechanical model of agonist-initiated contraction in the asthmatic airway.

PubMed

Brook, B S; Peel, S E; Hall, I P; Politi, A Z; Sneyd, J; Bai, Y; Sanderson, M J; Jensen, O E

2010-01-31

This paper presents a modelling framework in which the local stress environment of airway smooth muscle (ASM) cells may be predicted and cellular responses to local stress may be investigated. We consider an elastic axisymmetric model of a layer of connective tissue and circumferential ASM fibres embedded in parenchymal tissue and model the active contractile force generated by ASM via a stress acting along the fibres. A constitutive law is proposed that accounts for active and passive material properties as well as the proportion of muscle to connective tissue. The model predicts significantly different contractile responses depending on the proportion of muscle to connective tissue in the remodelled airway. We find that radial and hoop-stress distributions in remodelled muscle layers are highly heterogenous with distinct regions of compression and tension. Such patterns of stress are likely to have important implications, from a mechano-transduction perspective, on contractility, short-term cytoskeletal adaptation and long-term airway remodelling in asthma. Copyright 2009 Elsevier B.V. All rights reserved.

Layer-by-layer assembly surface modified microbial biomass for enhancing biorecovery of secondary gold.

PubMed

Zhou, Ying; Zhu, Nengwu; Kang, Naixin; Cao, Yanlan; Shi, Chaohong; Wu, Pingxiao; Dang, Zhi; Zhang, Xiaoping; Qin, Benqian

2017-02-01

Enhancement of the biosorption capacity for gold is highly desirable for the biorecovery of secondary gold resources. In this study, polyethylenimine (PEI) was grafted on Shewanella haliotis surface through layer-by-layer assembly approach so as to improve the biosorption capacity of Au(III). Results showed that the relative contribution of amino group to the biosorption of Au(III) was the largest one (about 44%). After successful grafting 1, 2 and 3-layer PEI on the surface of biomass, the biosorption capacity significantly enhanced from 143.8mg/g to 597.1, 559.1, and 536.8mg/g, respectively. Interestingly, the biomass modified with 1-layer PEI exhibited 4.2 times higher biosorption capacity than the untreated control. When 1-layer modified biomass was subjected to optimizing the various conditions by response surface methodology, the theoretical maximum adsorption capacity could reach up to 727.3mg/g. All findings demonstrated that PEI modified S. haliotis was effective for enhancing gold biorecovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Turbulent Boundary Layer Flow over Superhydrophobic Surfaces

DTIC Science & Technology

2013-05-10

DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Turbulent Boundary Layer Flow over Superhydrophobic ...modified surfaces. This study encompassed the testing of four different surfaces: 1) Teflon SLIP, 2) Aluminum SLIP, 3) Honeycomb Superhydrophobic and 4...Polydimethylsiloxane elastomer (PDMSe) Superhydrophobic . Each of these surfaces uses specific geometrical surface features to modify the original

Modelling hazardous surface hoar layers in the mountain snowpack over space and time

NASA Astrophysics Data System (ADS)

Horton, Simon Earl

Surface hoar layers are a common failure layer in hazardous snow slab avalanches. Surface hoar crystals (frost) initially form on the surface of the snow, and once buried can remain a persistent weak layer for weeks or months. Avalanche forecasters have difficulty tracking the spatial distribution and mechanical properties of these layers in mountainous terrain. This thesis presents numerical models and remote sensing methods to track the distribution and properties of surface hoar layers over space and time. The formation of surface hoar was modelled with meteorological data by calculating the downward flux of water vapour from the atmospheric boundary layer. The timing of surface hoar formation and the modelled crystal size was verified at snow study sites throughout western Canada. The major surface hoar layers over several winters were predicted with fair success. Surface hoar formation was modelled over various spatial scales using meteorological data from weather forecast models. The largest surface hoar crystals formed in regions and elevation bands with clear skies, warm and humid air, cold snow surfaces, and light winds. Field surveys measured similar regional-scale patterns in surface hoar distribution. Surface hoar formation patterns on different slope aspects were observed, but were not modelled reliably. Mechanical field tests on buried surface hoar layers found layers increased in shear strength over time, but had persistent high propensity for fracture propagation. Layers with large crystals and layers overlying hard melt-freeze crusts showed greater signs of instability. Buried surface hoar layers were simulated with the snow cover model SNOWPACK and verified with avalanche observations, finding most hazardous surface hoar layers were identified with a structural stability index. Finally, the optical properties of surface hoar crystals were measured in the field with spectral instruments. Large plate-shaped crystals were less reflective at shortwave

Durable superhydrophobic surfaces made by intensely connecting a bipolar top layer to the substrate with a middle connecting layer.

PubMed

Zhi, Jinghui; Zhang, Li-Zhi

2017-08-30

This study reported a simple fabrication method for a durable superhydrophobic surface. The superhydrophobic top layer of the durable superhydrophobic surface was connected intensely to the substrate through a middle connecting layer. Glycidoxypropyltrimethoxysilane (KH-560) after hydrolysis was used to obtain a hydrophilic middle connecting layer. It could be adhered to the hydrophilic substrate by covalent bonds. Ring-open reaction with octadecylamine let the KH-560 middle layer form a net-like structure. The net-like sturcture would then encompass and station the silica particles that were used to form the coarse micro structures, intensely to increase the durability. The top hydrophobic layer with nano-structures was formed on the KH-560 middle layer. It was obtained by a bipolar nano-silica solution modified by hexamethyldisilazane (HMDS). This layer was connected to the middle layer intensely by the polar Si hydroxy groups, while the non-polar methyl groups on the surface, accompanied by the micro and nano structures, made the surface rather hydrophobic. The covalently interfacial interactions between the substrate and the middle layer, and between the middle layer and the top layer, strengthened the durability of the superhydrophobic surface. The abrasion test results showed that the superhydrophobic surface could bear 180 abrasion cycles on 1200 CW sandpaper under 2 kPa applied pressure.

Characteristics of the Martian atmosphere surface layer

NASA Technical Reports Server (NTRS)

Clow, G. D.; Haberle, R. M.

1990-01-01

Elements of various terrestrial boundary layer models are extended to Mars in order to estimate sensible heat, latent heat, and momentum fluxes within the Martian atmospheric surface ('constant flux') layer. The atmospheric surface layer consists of an interfacial sublayer immediately adjacent to the ground and an overlying fully turbulent surface sublayer where wind-shear production of turbulence dominates buoyancy production. Within the interfacial sublayer, sensible and latent heat are transported by non-steady molecular diffusion into small-scale eddies which intermittently burst through this zone. Both the thickness of the interfacial sublayer and the characteristics of the turbulent eddies penetrating through it depend on whether airflow is aerodynamically smooth or aerodynamically rough, as determined by the Roughness Reynold's number. Within the overlying surface sublayer, similarity theory can be used to express the mean vertical windspeed, temperature, and water vapor profiles in terms of a single parameter, the Monin-Obukhov stability parameter. To estimate the molecular viscosity and thermal conductivity of a CO2-H2O gas mixture under Martian conditions, parameterizations were developed using data from the TPRC Data Series and the first-order Chapman-Cowling expressions; the required collision integrals were approximated using the Lenard-Jones potential. Parameterizations for specific heat and binary diffusivity were also determined. The Brutsart model for sensible and latent heat transport within the interfacial sublayer for both aerodynamically smooth and rough airflow was experimentally tested under similar conditions, validating its application to Martian conditions. For the surface sublayer, the definition of the Monin-Obukhov length was modified to properly account for the buoyancy forces arising from water vapor gradients in the Martian atmospheric boundary layer. It was found that under most Martian conditions, the interfacial and surface

CXCR3 surface expression in human airway epithelial cells: cell cycle dependence and effect on cell proliferation.

PubMed

Aksoy, Mark O; Yang, Yi; Ji, Rong; Reddy, P J; Shahabuddin, Syed; Litvin, Judith; Rogers, Thomas J; Kelsen, Steven G

2006-05-01

We recently demonstrated that human bronchial epithelial cells (HBEC) constitutively express the CXC chemokine receptor CXCR3, which when activated, induces directed cell migration. The present study in HBEC examined the relative expression of the CXCR3 splice variants CXCR3-A and -B, cell cycle dependence of CXCR3 expression, and the effects of the CXCR3 ligand, the interferon-gamma-inducible CXC chemokine I-TAC/CXCL11, on DNA synthesis and cell proliferation. Both CXCR3-A and -B mRNA, assessed by real-time RT-PCR, were expressed in normal HBEC (NHBEC) and the HBEC line 16-HBE. However, CXCR3-B mRNA was 39- and 6-fold greater than CXCR3-A mRNA in NHBEC and 16-HBE, respectively. Although most HBEC (>80%) assessed by flow cytometry and immunofluorescence microscopy contained intracellular CXCR3, only a minority (<40%) expressed it on the cell surface. In this latter subset of cells, most (>75%) were in the S + G(2)/M phases of the cell cycle. Stimulation of CXCR3 with I-TAC enhanced thymidine incorporation and cell proliferation and increased p38 and ERK1/2 phosphorylation. These data indicate that 1) human airway epithelial cells primarily express CXCR3-B mRNA, 2) surface expression of CXCR3 is largely confined to the S + G(2)/M phases of the cell cycle, and 3) activation of CXCR3 induces DNA synthesis, cell proliferation, and activation of MAPK pathways. We speculate that activation of CXCR3 exerts a mitogenic effect in HBEC, which may be important during airway mucosal injury in obstructive airway diseases such as asthma and chronic obstructive pulmonary disease.

Effect of surface ionization on wetting layers

NASA Technical Reports Server (NTRS)

Kayser, R. F.

1986-01-01

A surface ionization model due to Langmuir is generalized to liquid mixtures of polar and nonpolar components in contact with ionizable substrates. When a predominantly nonpolar mixture is near a miscibility gap, thick wetting layers of the conjugate polar phase form on the substrate. Such charged layers can be much thicker than similar wetting layers stabilized by dispersion forces. This model may explain the 0.4- to 0.6-micron-thick wetting layers formed in stirred mixtures of nitromethane and carbon disulfide in contact with glass.

Antiferromagnetic MnN layer on the MnGa(001) surface

NASA Astrophysics Data System (ADS)

Guerrero-Sánchez, J.; Takeuchi, Noboru

2016-12-01

Spin polarized first principles total energy calculations have been applied to study the stability and magnetic properties of the MnGa(001) surface and the formation of a topmost MnN layer with the deposit of nitrogen. Before nitrogen adsorption, surface formation energies show a stable gallium terminated ferromagnetic surface. After incorporation of nitrogen atoms, the antiferromagnetic manganese terminated surface becomes stable due to the formation of a MnN layer (Mn-N bonding at the surface). Spin density distribution shows a ferromagnetic/antiferromagnetic arrangement in the first surface layers. This thermodynamically stable structure may be exploited to growth MnGa/MnN magnetic heterostructures as well as to look for exchange biased systems.

Vitronectin Expression in the Airways of Subjects with Asthma and Chronic Obstructive Pulmonary Disease

PubMed Central

Salazar-Peláez, Lina M.; Abraham, Thomas; Herrera, Ana M.; Correa, Mario A.; Ortega, Jorge E.; Paré, Peter D.; Seow, Chun Y.

2015-01-01

Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration, wound healing, and tissue remodeling. The primary cellular source of vitronectin is hepatocytes; it is not known whether resident cells of airways produce vitronectin, even though the glycoprotein has been found in exhaled breath condensate and bronchoalveolar lavage from healthy subjects and patients with interstitial lung disease. It is also not known whether vitronectin expression is altered in subjects with asthma and COPD. In this study, bronchial tissue from 7 asthmatic, 10 COPD and 14 control subjects was obtained at autopsy and analyzed by immunohistochemistry to determine the percent area of submucosal glands occupied by vitronectin. In a separate set of experiments, quantitative colocalization analysis was performed on tracheobronchial tissue sections obtained from donor lungs (6 asthmatics, 4 COPD and 7 controls). Vitronectin RNA and protein expressions in bronchial surface epithelium were examined in 12 subjects who undertook diagnostic bronchoscopy. Vitronectin was found in the tracheobronchial epithelium from asthmatic, COPD, and control subjects, although its expression was significantly lower in the asthmatic group. Colocalization analysis of 3D confocal images indicates that vitronectin is expressed in the glandular serous epithelial cells and in respiratory surface epithelial cells other than goblet cells. Expression of the 65-kDa vitronectin isoform was lower in bronchial surface epithelium from the diseased subjects. The cause for the decreased vitronectin expression in asthma is not clear, however, the reduced concentration of vitronectin in the epithelial/submucosal layer of airways may be linked to airway remodeling. PMID:25768308

Contact mechanics for layered materials with randomly rough surfaces.

PubMed

Persson, B N J

2012-03-07

The contact mechanics model of Persson is applied to layered materials. We calculate the M function, which relates the surface stress to the surface displacement, for a layered material, where the top layer (thickness d) has different elastic properties than the semi-infinite solid below. Numerical results for the contact area as a function of the magnification are presented for several cases. As an application, we calculate the fluid leak rate for laminated rubber seals.

Expansible apparatus for removing the surface layer from a concrete object

DOEpatents

Allen, Charles H.

1979-01-01

A method and apparatus for removing the surface layer from a concrete object. The method consists of providing a hole having a circular wall in the surface layer of the object, the hole being at least as deep as the thickness of the surface layer to be removed, and applying an outward wedging pressure on the wall of the hole sufficient to spall the surface layer around the hole. By the proper spacing of an appropriate number of holes, it is possible to remove the entire surface layer from an object. The apparatus consists of an elongated tubular-shaped body having a relatively short handle with a solid wall at one end, the wall of the remainder of the body containing a plurality of evenly spaced longitudinal cuts to form a relatively long expandable section, the outer end of the expandable section having an expandable, wedge-shaped spalling edge extending from the outer surface of the wall, perpendicular to the longitudinal axis of the body, and expanding means in the body for outwardly expanding the expandable section and forcing the spalling edge into the wall of a hole with sufficient outward pressure to spall away the surface layer of concrete. The method and apparatus are particularly suitable for removing surface layers of concrete which are radioactively contaminated.

Electrografted diazonium salt layers for antifouling on the surface of surface plasmon resonance biosensors.

PubMed

Zou, Qiongjing; Kegel, Laurel L; Booksh, Karl S

2015-02-17

Electrografted diazonium salt layers on the surface of surface plasmon resonance (SPR) sensors present potential for a significant improvement in antifouling coatings. A pulsed potential deposition profile was used in order to circumvent mass-transport limitations for layer deposition rate. The influence of number of pulses with respect to antifouling efficacy was evaluated by nonspecific adsorption surface coverage of crude bovine serum proteins. Instead of using empirical and rough estimated values, the penetration depth and sensitivity of the SPR instrument were experimentally determined for the calculation of nonspecific adsorption surface coverage. This provides a method to better examine antifouling surface coatings and compare crossing different coatings and experimental systems. Direct comparison of antifouling performance of different diazonium salts was facilitated by a tripad SPR sensor design. The electrografted 4-phenylalanine diazonium chloride (4-APhe) layers with zwitterionic characteristic demonstrate ultralow fouling.

Detection of airway ischaemic damage after lung transplantation by using autofluorescence imaging bronchoscopy.

PubMed

Iga, Norichika; Oto, Takahiro; Okada, Masanori; Harada, Masaaki; Nishikawa, Hitoshi; Miyoshi, Kentaroh; Otani, Shinji; Sugimoto, Seiichiro; Yamane, Masaomi; Toyooka, Shinichi; Miyoshi, Shinichiro

2014-03-01

Airway complications related to ischaemia are a major cause of morbidity after lung transplantation. Early detection of airway ischaemia and optimal management of the anastomotic site could reduce the risk of airway complications. Autofluorescence imaging (AFI) bronchoscopy has been increasingly recognized as an effective technique for detecting abnormal mucosal thickening. The aim of this study was to investigate whether AFI bronchoscopy can facilitate the detection of airway ischaemic damage in lung transplant patients. Twenty Landrace pigs were used to create a tracheal autotransplantation model. A four-ring length of trachea was excised and implanted orthotopically. The tracheal autograft was observed on postoperative days 0, 2, 4 and 7 with AFI bronchoscopy. The extent and origin of graft autofluorescence were examined using histology and measured according to fluorescence intensity. The lesions on the tracheal autografts appeared as bright green fluorescence on AFI bronchoscopy. On confocal fluorescence microscopy, high-intensity green fluorescence was observed in the elastin fibre layer of the submucosa. The fluorescence intensity of elastin was significantly higher in the graft showing fluorescence than the graft that did not show fluorescence and that at the control site. Bright green fluorescence was seen in an elastin fibre layer in the submucosa, which was likely a result of epithelial sloughing. There is a close relationship between the bright green fluorescence pattern observed using AFI bronchoscopy and airway ischaemic damage. We conclude that AFI bronchoscopy may detect airway ischaemic damage after lung transplantation.

Surface boundary layer turbulence in the Southern ocean

NASA Astrophysics Data System (ADS)

Merrifield, Sophia; St. Laurent, Louis; Owens, Breck; Naveira Garabato, Alberto

2015-04-01

Due to the remote location and harsh conditions, few direct measurements of turbulence have been collected in the Southern Ocean. This region experiences some of the strongest wind forcing of the global ocean, leading to large inertial energy input. While mixed layers are known to have a strong seasonality and reach 500m depth, the depth structure of near-surface turbulent dissipation and diffusivity have not been examined using direct measurements. We present data collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) field program. In a range of wind conditions, the wave affected surface layer (WASL), where surface wave physics are actively forcing turbulence, is contained to the upper 15-20m. The lag-correlation between wind stress and turbulence shows a strong relationship up to 6 hours (˜1/2 inertial period), with the winds leading the oceanic turbulent response, in the depth range between 20-50m. We find the following characterize the data: i) Profiles that have a well-defined hydrographic mixed layer show that dissipation decays in the mixed layer inversely with depth, ii) WASLs are typically 15 meters deep and 30% of mixed layer depth, iii) Subject to strong winds, the value of dissipation as a function of depth is significantly lower than predicted by theory. Many dynamical processes are known to be missing from upper-ocean parameterizations of mixing in global models. These include surface-wave driven processes such as Langmuir turbulence, submesocale frontal processes, and nonlocal representations of mixing. Using velocity, hydrographic, and turbulence measurements, the existence of coherent structures in the boundary layer are investigated.

The contribution of airway smooth muscle to airway narrowing and airway hyperresponsiveness in disease.

PubMed

Martin, J G; Duguet, A; Eidelman, D H

2000-08-01

Airway hyperresponsiveness (AHR), the exaggerated response to constrictor agonists in asthmatic subjects, is incompletely understood. Changes in either the quantity or properties of airway smooth muscle (ASM) are possible explanations for AHR. Morphometric analyses demonstrate structural changes in asthmatic airways, including subepithelial fibrosis, gland hyperplasia/hypertrophy, neovascularization and an increase in ASM mass. Mathematical modelling of airway narrowing suggests that, of all the changes in structure, the increase in ASM mass is the most probable cause of AHR. An increase in ASM mass in the large airways is more closely associated with a greater likelihood of dying from asthma than increases in ASM mass in other locations within the airway tree. ASM contraction is opposed by the elastic recoil of the lungs and airways, which appears to limit the degree of bronchoconstriction in vivo. The cyclical nature of tidal breathing applies stresses to the airway wall that enhance the bronchodilating influence of the lung tissues on the contracting ASM, in all probability by disrupting cross-bridges. However, the increase in ASM mass in asthma may overcome the limitation resulting from the impedances to ASM shortening imposed by the lung parenchyma and airway wall tissues. Additionally, ASM with the capacity to shorten rapidly may achieve shorter lengths and cause a greater degree of bronchoconstriction when stimulated to contract than slower ASM. Changes in ASM properties are induced by the process of sensitization and allergen-exposure such as enhancement of phospholipase C activity and inositol phosphate turnover, and increases in myosin light chain kinase activity. Whether changes in ASM mass or biochemical/biomechanical properties form the basis for asthma remains to be determined.

Catheter-Based Sensing In The Airways

NASA Astrophysics Data System (ADS)

Fouke, J. M.; Saunders, K. G.

1988-04-01

Studies attempting to define the role of the respiratory tract in heating and humidifying inspired air point to the need for sensing many variables including airway wall and airstream temperatures, humidity, and surface fluid pH and osmolarity. In order to make such measurements in vivo in human volunteers, catheter based technologies must be exploited both to assure subject safety and subject comfort. Miniturization of the electrodes or sensors becomes a top priority. This paper describes the use of thin-film microelectronic technology to fabricate a miniature, flexible sensor which can be placed directly onto the surface of the airway to measure the electrical conductance of the fluids present. From this information the osmolarity of the surface fluid was calculated. Physiologic evaluation of the device and corroboration of the calculations was performed in mongrel dogs. We also describe the successful application of current thermistor technology for the thermal mapping of the airways in humans in order to characterize the dynamic intrathoracic events that occur during breathing. The thermal probe consisted of a flexible polyvinyl tube that contained fourteen small thermistors fixed into the catheter. Data have been obtained in dozens of people, both normal subjects and asthmatic patients, under a variety of interventions. These data have substantively advanced the study of asthma, a particularly troublesome chronic obstructive pulmonary disorder.

Application of atomic force microscopy to microbial surfaces: from reconstituted cell surface layers to living cells.

PubMed

Dufrêne, Y F

2001-02-01

The application of atomic force microscopy (AFM) to probe the ultrastructure and physical properties of microbial cell surfaces is reviewed. The unique capabilities of AFM can be summarized as follows: imaging surface topography with (sub)nanometer lateral resolution; examining biological specimens under physiological conditions; measuring local properties and interaction forces. AFM is being used increasingly for: (i) visualizing the surface ultrastructure of microbial cell surface layers, including bacterial S-layers, purple membranes, porin OmpF crystals and fungal rodlet layers; (ii) monitoring conformational changes of individual membrane proteins; (iii) examining the morphology of bacterial biofilms, (iv) revealing the nanoscale structure of living microbial cells, including fungi, yeasts and bacteria, (v) mapping interaction forces at microbial surfaces, such as van der Waals and electrostatic forces, solvation forces, and steric/bridging forces; and (vi) probing the local mechanical properties of cell surface layers and of single cells.

A scheme for computing surface layer turbulent fluxes from mean flow surface observations

NASA Technical Reports Server (NTRS)

Hoffert, M. I.; Storch, J.

1978-01-01

A physical model and computational scheme are developed for generating turbulent surface stress, sensible heat flux and humidity flux from mean velocity, temperature and humidity at some fixed height in the atmospheric surface layer, where conditions at this reference level are presumed known from observations or the evolving state of a numerical atmospheric circulation model. The method is based on coupling the Monin-Obukov surface layer similarity profiles which include buoyant stability effects on mean velocity, temperature and humidity to a force-restore formulation for the evolution of surface soil temperature to yield the local values of shear stress, heat flux and surface temperature. A self-contained formulation is presented including parameterizations for solar and infrared radiant fluxes at the surface. Additional parameters needed to implement the scheme are the thermal heat capacity of the soil per unit surface area, surface aerodynamic roughness, latitude, solar declination, surface albedo, surface emissivity and atmospheric transmissivity to solar radiation.

Layer by Layer, Nano-particle "Only" Surface Modification of Filtration Membranes

NASA Astrophysics Data System (ADS)

Escobar-Ferrand, Luis

Layer by Layer (LbL) deposition using primarily inorganic silica nanoparticles is employed for the modification of polymeric micro and ultrafiltration (MF/UF) membranes to produce thin film composites (TFC) with potential nanofiltration (NF) and reverse osmosis (RO) capabilities.. A variety of porous substrate membranes with different membrane surface characteristics are employed, but exhibiting in common that wicking of water does not readily occur into the pore structure, including polycarbonate track etched (PCTE), polyethersulfone (PES) and sulfonated PES (SPEES) MF/UF membranes. Both spherical (cationic/anionic) and eccentric elongated (anionic) silica nanoparticles are deposited using conditions similar to those reported by Lee et al. Appropriate selection of the pH's for anionic and cationic particle deposition enables the construction of nanoparticle only layers 100--1200 nm in thickness atop the original membrane substrates. The surface layer thickness varies monotonically with the number of bilayers (anionic/cationic deposition cycles) as expected. The deposition process is optimized to eliminate drying induced cracking and to improve mechanical durability via thickness control and post-deposition hydro-thermal treatment. The hydrodynamic permeability of these TFC membranes is measured to evaluate their performance under typical NF operating conditions using dead-end permeation experiments and their performance compared quantitatively with realistic hydrodynamic models, with favorable results. For track etched polycarbonate MF substrates, surface modification causes a permeability reduction of approximately two orders of magnitude with respect to the bare substrates, to values comparable to those for typical commercial NF membranes. Good quantitative agreement with hydrodynamic models with no adjustable parameters was also established for this case, providing indirect confirmation that the LbL deposited surface layers are largely defect (crack) free

Airway-parenchymal interdependence

PubMed Central

Paré, Peter D; Mitzner, Wayne

2015-01-01

In this manuscript we discuss the interaction of the lung parenchyma and the airways as well as the physiological and pathophysiological significance of this interaction. These two components of the respiratory organ can be thought of as two independent elastic structures but in fact the mechanical properties of one influence the behavior of the other. Traditionally the interaction has focused on the effects of the lung on the airways but there is good evidence that the opposite is also true, i.e., that the mechanical properties of the airways influence the elastic properties of the parenchyma. The interplay between components of the respiratory system including the airways, parenchyma and vasculature is often referred to as “interdependence.” This interdependence transmits the elastic recoil of the lung to create an effective pressure that dilates the airways as transpulmonary pressure and lung volume increase. By using a continuum mechanics analysis of the lung parenchyma, it is possible to predict the effective pressure between the airways and parenchyma, and these predictions can be empirically evaluated. Normal airway caliber is maintained by this pressure in the adventitial interstitium of the airway, and it counteracts airway compression during forced expiration as well as the ability of airway smooth muscle to narrow airways. Interdependence has physiological and pathophysiological significance. Weakening of the forces of interdependence contributes to airway dysfunction and gas exchange impairment in acute and chronic airway diseases including asthma and emphysema. PMID:23723029

Inhibition of Protease-Epithelial Sodium Channel Signaling Improves Mucociliary Function in Cystic Fibrosis Airways.

PubMed

Reihill, James A; Walker, Brian; Hamilton, Robert A; Ferguson, Timothy E G; Elborn, J Stuart; Stutts, M Jackson; Harvey, Brian J; Saint-Criq, Vinciane; Hendrick, Siobhan M; Martin, S Lorraine

2016-09-15

In cystic fibrosis (CF) a reduction in airway surface liquid (ASL) height compromises mucociliary clearance, favoring mucus plugging and chronic bacterial infection. Inhibitors of the epithelial sodium channel (ENaC) have therapeutic potential in CF airways to reduce hyperstimulated sodium and fluid absorption to levels that can restore airway hydration. To determine whether a novel compound (QUB-TL1) designed to inhibit protease/ENaC signaling in CF airways restores ASL volume and mucociliary function. Protease activity was measured using fluorogenic activity assays. Differentiated primary airway epithelial cell cultures (F508del homozygotes) were used to determined ENaC activity (Ussing chamber recordings), ASL height (confocal microscopy), and mucociliary function (by tracking the surface flow of apically applied microbeads). Cell toxicity was measured using a lactate dehydrogenase assay. QUB-TL1 inhibits extracellularly located channel activating proteases (CAPs), including prostasin, matriptase, and furin, the activities of which are observed at excessive levels at the apical surface of CF airway epithelial cells. QUB-TL1-mediated CAP inhibition results in diminished ENaC-mediated Na(+) absorption in CF airway epithelial cells caused by internalization of a prominent pool of cleaved (active) ENaCγ from the cell surface. Importantly, diminished ENaC activity correlates with improved airway hydration status and mucociliary clearance. We further demonstrate QUB-TL1-mediated furin inhibition, which is in contrast to other serine protease inhibitors (camostat mesylate and aprotinin), affords protection against neutrophil elastase-mediated ENaC activation and Pseudomonas aeruginosa exotoxin A-induced cell death. QUB-TL1 corrects aberrant CAP activities, providing a mechanism to delay or prevent the development of CF lung disease in a manner independent of CF transmembrane conductance regulator mutation.

Defective postsecretory maturation of MUC5B mucin in cystic fibrosis airways

PubMed Central

Abdullah, Lubna H.; Evans, Jessica R.; Wang, T. Tiffany; Ford, Amina A.; Makhov, Alexander M.; Nguyen, Kristine; Coakley, Raymond D.; Griffith, Jack D.; Davis, C. William; Ballard, Stephen T.

2017-01-01

In cystic fibrosis (CF), airway mucus becomes thick and viscous, and its clearance from the airways is impaired. The gel-forming mucins undergo an ordered “unpacking/maturation” process after granular release that requires an optimum postsecretory environment, including hydration and pH. We hypothesized that this unpacking process is compromised in the CF lung due to abnormal transepithelial fluid transport that reduces airway surface hydration and alters ionic composition. Using human tracheobronchial epithelial cells derived from non-CF and CF donors and mucus samples from human subjects and domestic pigs, we investigated the process of postsecretory mucin unfolding/maturation, how these processes are defective in CF airways, and the probable mechanism underlying defective unfolding. First, we found that mucins released into a normal lung environment transform from a compact granular form to a linear form. Second, we demonstrated that this maturation process is defective in the CF airway environment. Finally, we demonstrated that independent of HCO3− and pH levels, airway surface dehydration was the major determinant of this abnormal unfolding process. This defective unfolding/maturation process after granular release suggests that the CF extracellular environment is ion/water depleted and likely contributes to abnormal mucus properties in CF airways prior to infection and inflammation. PMID:28352653

Linking Dynamics of the Near-surface Flow to Deeper Boundary Layer Forcing in the Nocturnal Boundary Layer

DTIC Science & Technology

2012-06-01

Kaimal and Finnigan (1994), modified) Figure 2.2 illustrates the evolution from unstable CBL to a nocturnal Stable Bound- ary Layer ( SBL ) in the absence...mixed layer acts as a cap for the SBL . The SBL persists through the night until sunrise when surface heating resumes and a new unstable layer begins...to form at the surface, gradually returning to a CBL. 7 2.2.1 Dynamics of the stable boundary layer Because the SBL is stably stratified, buoyancy

Color analysis of the human airway wall

NASA Astrophysics Data System (ADS)

Gopalakrishnan, Deepa; McLennan, Geoffrey; Donnelley, Martin; Delsing, Angela; Suter, Melissa; Flaherty, Dawn; Zabner, Joseph; Hoffman, Eric A.; Reinhardt, Joseph M.

2002-04-01

A bronchoscope can be used to examine the mucosal surface of the airways for abnormalities associated with a variety of lung diseases. The diagnosis of these abnormalities through the process of bronchoscopy is based, in part, on changes in airway wall color. Therefore it is important to characterize the normal color inside the airways. We propose a standardized method to calibrate the bronchoscopic imaging system and to tabulate the normal colors of the airway. Our imaging system consists of a Pentium PC and video frame grabber, coupled with a true color bronchoscope. The calibration procedure uses 24 standard color patches. Images of these color patches at three different distances (1, 1.5, and 2 cm) were acquired using the bronchoscope in a darkened room, to assess repeatability and sensitivity to illumination. The images from the bronchoscope are in a device-dependent Red-Green-Blue (RGB) color space, which was converted to a tri-stimulus image and then into a device-independent color space sRGB image by a fixed polynomial transformation. Images were acquired from five normal human volunteer subjects, two cystic fibrosis (CF) patients and one normal heavy smoker subject. The hue and saturation values of regions within the normal airway were tabulated and these values were compared with the values obtained from regions within the airways of the CF patients and the normal heavy smoker. Repeated measurements of the same region in the airways showed no measurable change in hue or saturation.

Modeling the surface of Campylobacter fetus: protein surface layer stability and resistance to cationic antimicrobial peptides.

PubMed

Roberts, James M D; Graham, Lori L; Quinn, Bonnie; Pink, David A

2013-03-01

Campylobacter fetus is a Gram negative bacterium recognized for its virulence in animals and humans. This bacterium possesses a paracrystalline array of high molecular weight proteins known as surface-layer proteins covering its cell surface. A mathematical model has been made of the outer membrane of this bacterium, both with its surface-layer proteins (S+) and without (S-). Monte Carlo computer simulation was used to understand the stability of the surface-layer protein structure as a function of ionic concentration. The interactions of an electrically-charged antimicrobial agent, the cationic antimicrobial peptide protamine, with surface-layer proteins and with the lipopolysaccharides of the outer membrane were modeled and analyzed. We found that (1) divalent ions stabilize the surface-layer protein array by reducing the fluctuations perpendicular and parallel to the membrane plane thereby promoting adhesion to the LPS region. This was achieved via (2) divalent ions bridging the negatively-charged LPS Core. The effect of this bridging is to bring individual Core regions closer together so that the O-antigens can (3) increase their attractive van der Waals interactions and "collapse" to form a surface with reduced perpendicular fluctuations. These findings provide support for the proposal of Yang et al. [1]. (4) No evidence for a significant increase in Ca(2+) concentration in the region of the surface-layer protein subunits was observed in S+ simulations compared to S- simulations. (5) We predicted the trends of protamine MIC tests performed on C. fetus and these were in good agreement with our experimental results. Copyright © 2012 Elsevier B.V. All rights reserved.

Trefoil factor-2 reverses airway remodeling changes in allergic airways disease.

PubMed

Royce, Simon G; Lim, Clarice; Muljadi, Ruth C; Samuel, Chrishan S; Ververis, Katherine; Karagiannis, Tom C; Giraud, Andrew S; Tang, Mimi L K

2013-01-01

Trefoil factor 2 (TFF2) is a small peptide with an important role in mucosal repair. TFF2 is up-regulated in asthma, suggesting a role in asthma pathogenesis. Given its known biological role in promoting epithelial repair, TFF2 might be expected to exert a protective function in limiting the progression of airway remodeling in asthma. The contribution of TFF2 to airway remodeling in asthma was investigated by examining the expression of TFF2 in the airway and lung, and evaluating the effects of recombinant TFF2 treatment on established airway remodeling in a murine model of chronic allergic airways disease (AAD). BALB/c mice were sensitized and challenged with ovalbumin (OVA) or saline for 9 weeks, whereas mice with established OVA-induced AAD were treated with TFF2 or vehicle control (intranasally for 14 d). Effects on airway remodeling, airway inflammation, and airway hyperresponsiveness were then assessed, whereas TFF2 expression was determined by immunohistochemistry. TFF2 expression was significantly increased in the airways of mice with AAD, compared with expression levels in control mice. TFF2 treatment resulted in reduced epithelial thickening, subepithelial collagen deposition, goblet-cell metaplasia, bronchial epithelium apoptosis, and airway hyperresponsiveness (all P < 0.05, versus vehicle control), but TFF2 treatment did not influence airway inflammation. The increased expression of endogenous TFF2 in response to chronic allergic inflammation is insufficient to prevent the progression of airway inflammation and remodeling in a murine model of chronic AAD. However, exogenous TFF2 treatment is effective in reversing aspects of established airway remodeling. TFF2 has potential as a novel treatment for airway remodeling in asthma.

Quantitative analysis of airway abnormalities in CT

NASA Astrophysics Data System (ADS)

Petersen, Jens; Lo, Pechin; Nielsen, Mads; Edula, Goutham; Ashraf, Haseem; Dirksen, Asger; de Bruijne, Marleen

2010-03-01

A coupled surface graph cut algorithm for airway wall segmentation from Computed Tomography (CT) images is presented. Using cost functions that highlight both inner and outer wall borders, the method combines the search for both borders into one graph cut. The proposed method is evaluated on 173 manually segmented images extracted from 15 different subjects and shown to give accurate results, with 37% less errors than the Full Width at Half Maximum (FWHM) algorithm and 62% less than a similar graph cut method without coupled surfaces. Common measures of airway wall thickness such as the Interior Area (IA) and Wall Area percentage (WA%) was measured by the proposed method on a total of 723 CT scans from a lung cancer screening study. These measures were significantly different for participants with Chronic Obstructive Pulmonary Disease (COPD) compared to asymptomatic participants. Furthermore, reproducibility was good as confirmed by repeat scans and the measures correlated well with the outcomes of pulmonary function tests, demonstrating the use of the algorithm as a COPD diagnostic tool. Additionally, a new measure of airway wall thickness is proposed, Normalized Wall Intensity Sum (NWIS). NWIS is shown to correlate better with lung function test values and to be more reproducible than previous measures IA, WA% and airway wall thickness at a lumen perimeter of 10 mm (PI10).

Layer Control of WSe2 via Selective Surface Layer Oxidation.

PubMed

Li, Zhen; Yang, Sisi; Dhall, Rohan; Kosmowska, Ewa; Shi, Haotian; Chatzakis, Ioannis; Cronin, Stephen B

2016-07-26

We report Raman and photoluminescence spectra of mono- and few-layer WSe2 and MoSe2 taken before and after exposure to a remote oxygen plasma. For bilayer and trilayer WSe2, we observe an increase in the photoluminescence intensity and a blue shift of the photoluminescence peak positions after oxygen plasma treatment. The photoluminescence spectra of trilayer WSe2 exhibit features of a bilayer after oxygen plasma treatment. Bilayer WSe2 exhibits features of a monolayer, and the photoluminescence of monolayer WSe2 is completely absent after the oxygen plasma treatment. These changes are observed consistently in more than 20 flakes. The mechanism of the changes observed in the photoluminescence spectra of WSe2 is due to the selective oxidation of the topmost layer. As a result, N-layer WSe2 is reduced to N-1 layers. Raman spectra and AFM images taken from the WSe2 flakes before and after the oxygen treatment corroborate these findings. Because of the low kinetic energy of the oxygen radicals in the remote oxygen plasma, the oxidation is self-limiting. By varying the process duration from 1 to 10 min, we confirmed that the oxidation will only affect the topmost layer of the WSe2 flakes. X-ray photoelectron spectroscopy shows that the surface layer WOx of the sample can be removed by a quick dip in KOH solution. Therefore, this technique provides a promising way of controlling the thickness of WSe2 layer by layer.

Marine Atmospheric Surface Layer and Its Application to Electromagnetic Wave Propagation

NASA Astrophysics Data System (ADS)

Wang, Q.

2015-12-01

An important application of the atmospheric surface layer research is to characterize the near surface vertical gradients in temperature and humidity in order to predict radar and radio communication conditions in the environment. In this presentation, we will give an overview of a new research initiative funded under the Office of Naval Research (ONR) Multi-University Research Initiative (MURI): the Coupled Air-Sea Processes and EM Ducting Research (CASPER). The objective is to fully characterize the marine atmospheric boundary layer (MABL) as an electromagnetic (EM) propagation environment with the emphasis of spatial and temporal heterogeneities and surface wave/swell effects, both of which contravene the underlying assumptions of Monin-Obukhov Similarity Theory (MOST) used in coupled environmental forecast models. Furthermore, coastal variability in the inversion atop the MABL presents a challenge to forecast models and also causes practical issues in EM prediction models. These issues are the target of investigation of CASPER. CASPER measurement component includes two major field campaigns: CASPER-East (2015 Duck, NC) and CASPER-West (2018 southern California). This presentation will show the extensive measurements to be made during the CASPER -East field campaign with the focus on the marine atmospheric surface layer measurements with two research vessels, two research aircraft, surface flux buoy, wave gliders, ocean gliders, tethered balloons, and rawinsondes. Unlike previous research on the marine surface layer with the focus on surface fluxes and surface flux parameterization, CASPER field campaigns also emphasize of the surface layer profiles and the validation of the surface layer flux-profile relationship originally derived over land surfaces. Results from CASPER pilot experiment and preliminary results from CASPER-East field campaign will be discussed.

Patterns of recruitment and injury in a heterogeneous airway network model

PubMed Central

Stewart, Peter S.; Jensen, Oliver E.

2015-01-01

In respiratory distress, lung airways become flooded with liquid and may collapse due to surface-tension forces acting on air–liquid interfaces, inhibiting gas exchange. This paper proposes a mathematical multiscale model for the mechanical ventilation of a network of occluded airways, where air is forced into the network at a fixed tidal volume, allowing investigation of optimal recruitment strategies. The temporal response is derived from mechanistic models of individual airway reopening, incorporating feedback on the airway pressure due to recruitment. The model accounts for stochastic variability in airway diameter and stiffness across and between generations. For weak heterogeneity, the network is completely ventilated via one or more avalanches of recruitment (with airways recruited in quick succession), each characterized by a transient decrease in the airway pressure; avalanches become more erratic for airways that are initially more flooded. However, the time taken for complete ventilation of the network increases significantly as the network becomes more heterogeneous, leading to increased stresses on airway walls. The model predicts that the most peripheral airways are most at risk of ventilation-induced damage. A positive-end-expiratory pressure reduces the total recruitment time but at the cost of larger stresses exerted on airway walls. PMID:26423440

Surface Layering Near Room Temperature in a Nonmetallic Liquid

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sudeshna; Stripe, Benjamin; Shively, Patrick; Evmenenko, Geunnadi; Dutta, Pulak; Ehrlich, Steven; Mo, Haiding

2009-03-01

Oscillatory density profiles (layers) have been observed at the free surfaces of many liquid metals at and above room temperature [1]. A surface-layered state has been previously reported only in one dielectric liquid, tetrakis(2-ethylhexoxy)silane (TEHOS), and only at lower temperatures [2]. We have used x-ray reflectivity to study a molecular liquid, pentaphenyl trimethyl trisiloxane. Below T˜ 267K (well above the freezing point for this liquid), density oscillations appear at the surface. This liquid has a higher Tc (˜1200K) than TEHOS (˜950K), so that layers appear at T/Tc 0.2 in both cases. Our results indicate that surface order is a universal phenomenon in both metallic and dielectric liquids, and that the underlying physics is likely to be the same since layers always appear at T<˜0.2Tc as theoretically predicted [3] [3pt] REFERENCES: [0pt] [1]. e.g. O. M. Magnussen et al., Phys. Rev. Lett. 74, 4444 (1995) [0pt] [2]. H. Mo et al. Phys. Rev. Lett. 96, 096107 (2006); Phys. Rev. B 76, 024206 (2007) [0pt] [3]. e.g. E. Chac'on et al., Phys. Rev. Lett. 87, 166101 (2001)

Real-time assessment of surface interactions with titanium passivation layer by surface plasmon resonance

PubMed Central

Hirata, Isao; Yoshida, Yasuhiro; Nagaoka, Noriyuki; Hiasa, Kyou; Abe, Yasuhiko; Maekawa, Kenji; Kuboki, Takuo; Akagawa, Yasumasa; Suzuki, Kazuomi; Van Meerbeek, Bart; Messersmith, Phillip B.; Okazaki, Masayuki

2011-01-01

The high corrosion resistance and strength-to-density ratio makes titanium widely used in major industry, but also in a gamut of medical applications. Here we report for the first time on our development of a titanium passivation layer sensor that makes use of surface plasmon resonance (SPR). The deposited titanium metal layer on the sensor was passivated in air, like titanium medical devices. Our ‘Ti-SPR sensor’ enables analysis of biomolecules interactions with the passivated surface of titanium in real time. As a proof of concept, corrosion of titanium passivation layer exposed to acid was monitored in real time. Also, the Ti-SPR sensor can accurately measure the time-dependence of protein adsorption onto titanium passivation layer with a sub-nanogram per square millimeter accuracy. Besides such SPR analyses, an SPR-imaging (SPRI) enables real-time assessment of chemical surface processes that occur simultaneously at ‘multiple independent spots’ on the Ti-SPR sensor, such as acid-corrosion or adhesion of cells. Our Ti-SPR sensor will therefore be very useful to study titanium-corrosion phenomena and biomolecular titanium-surface interactions with application in a broad range of industrial and biomedical fields. PMID:22154862

Surface Brillouin scattering study of the surface excitations in amorphous silicon layers produced by ion bombardment

NASA Astrophysics Data System (ADS)

Zhang, X.; Comins, J. D.; Every, A. G.; Stoddart, P. R.; Pang, W.; Derry, T. E.

1998-11-01

Thin amorphous silicon layers on crystalline silicon substrates have been produced by argon-ion bombardment of (001) silicon surfaces. Thermally induced surface excitations characteristic of this example of a soft-on-hard system have been investigated by surface Brillouin scattering (SBS) as a function of scattering-angle and amorphous-layer thickness. At large scattering angles or for sufficiently large layer thickness, a second peak is present in the SBS spectrum near the low-energy threshold for the continuum of bulk excitations of the system. The measured spectra are analyzed on the basis of surface elastodynamic Green's functions, which successfully simulate their detailed appearance and identify the second peak as either a Sezawa wave (true surface wave) or a pseudo-Sezawa wave (attenuated surface wave) depending on the scattering parameters. The attributes of the pseudo-Sezawa wave are described; these include its asymmetrical line shape and variation in intensity with k∥d (the product of the surface excitation wave vector and the layer thickness), and its emergence as the Sezawa wave from the low-energy side of the Lamb shoulder at a critical value of k∥d. Furthermore, the behavior of a pronounced minimum in the Lamb shoulder near the longitudinal wave threshold observed in the experiments is reported and is found to be in good agreement with the calculated spectra. The elastic constants of the amorphous silicon layer are determined from the velocity dispersion of the Rayleigh surface acoustic wave and the minimum in the Lamb shoulder.

Discovery of Cellulose Surface Layer Conformation by Nonlinear Vibrational Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Libing; Fu, Li; Wang, Hong-fei

2017-03-14

Significant questions remain with respect to the structure and polymorphs of cellulose. These include the cellulose surface layers and the bulk crystalline core as well as the conformational differences. The Total Internal Reflection Sum Frequency Generation Vibrational Spectroscopy (TIR-SFG-VS) combined with the conventional SFG-VS (non-TIR) can help to resolve these questions by selectively characterizing the molecular structures of surface layers and the crystalline core of cellulose. From the SFG spectra in the C-H and O-H regions, we found that the surface layers of Avicel are essentially amorphous; while the surface layers of Iβ cellulose are crystalline but with different structuralmore » and spectroscopic signatures than that of its crystalline core. This work demonstrates the capacity of TIR and Non-TIR SFG-VS tools in selectively studying the structures and polymorphs of cellulose. In addition, these results also suggest that the assignments of major vibrational peaks for cellulose need to be further determined.« less

A model of the planetary boundary layer over a snow surface

NASA Technical Reports Server (NTRS)

Halberstam, I.; Melendez, R.

1979-01-01

A model of the planetary boundary layer over a snow surface has been developed. It contains the vertical heat exchange processes due to radiation, conduction, and atmospheric turbulence. Parametrization of the boundary layer is based on similarity functions developed by Hoffert and Sud (1976), which involve a dimensionless variable, dependent on boundary-layer height and a localized Monin-Obukhov length. The model also contains the atmospheric surface layer and the snowpack itself, where snowmelt and snow evaporation are calculated. The results indicate a strong dependence of surface temperatures, especially at night, on the bursts of turbulence which result from the frictional damping of surface-layer winds during periods of high stability, as described by Businger (1973). The model also shows the cooling and drying effect of the snow on the atmosphere, which may be the mechanism for air mass transformation in sub-Arctic regions.

Characteristics of the Martian atmosphere surface layer

NASA Technical Reports Server (NTRS)

Clow, G. D.; Haberle, R. M.

1991-01-01

Researchers extend elements of various terrestrial boundary layer models to Mars in order to estimate sensible heat, latent heat, and momentum fluxes within the Martian atmospheric surface layer. To estimate the molecular viscosity and thermal conductivity of a CO2-H2O gas mixture under Martian conditions, parameterizations were developed. Parameterizations for specific heat and and binary diffusivity were also determined. The Prandtl and Schmidt numbers derived from these thermophysical properties were found to range from 0.78 - 1.0 and 0.47 - 0.70, respectively, for Mars. Brutsaert's model for sensible and latent heat transport within the interfacial sublayer for both aerodynamically smooth and rough airflow was experimentally tested under similar conditions, validating its application to Martian conditions. For the surface sublayer, the researchers modified the definition of the Monin-Obukhov length to properly account for the buoyancy forces arising from water vapor gradients in the Martian atmospheric boundary layer. This length scale was then utilized with similarity theory turbulent flux profiles with the same form as those used by Businger et al. and others. It was found that under most Martian conditions, the interfacial and surface sublayers offer roughly comparable resistance to sensible heat and water vapor transport and are thus both important in determining the associated fluxes.

[A surface reacted layer study of titanium-zirconium alloy after dental casting].

PubMed

Zhang, Y; Guo, T; Li, Z; Li, C

2000-10-01

To investigate the influence of the mold temperature on the surface reacted layer of Ti-Zr alloy castings. Ti-Zr alloy was casted into a mold which was made of a zircon (ZrO2.SiO2) for inner coating and a phosphate-bonded material for outer investing with a casting machine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300 degrees C, 600 degrees C) the Ti-Zr alloy was casted separately. The surface roughness of the castings was calculated by instrument of smooth finish (China). From the surface to the inner part the Knoop hardness and thickness in reacted layer of Ti-Zr alloy casting was measured. The structure of the surface reacted layer was analysed by SEM. Elemental analyses of the interfacial zone of the casting was made by element line scanning observation. The surface roughness of the castings was increased significantly with the mold temperature increasing. At a higher mold temperature the Knoop hardness of the reactive layer was increased. At the three mold temperature the outmost surface was very hard, and microhardness data decreased rapidly where they reached constant values. The thickness was about 85 microns for castings at room temperature and 300 degrees C, 105 microns for castings at 600 degrees C. From the SEM micrograph of the Ti-Zr alloy casting, the surface reacted layer could be divided into three different layers. The first layer was called non-structure layer, which thickness was about 10 microns for room temperature group, 20 microns for 300 degrees C and 25 microns for 600 degrees C. The second layer was characterized by coarse-grained acicular crystal, which thickness was about 50 microns for three mold temperatures. The third layer was Ti-Zr alloy. The element line scanning showed non-structure layer with higher level of element of O, Al, Si and Zr, The higher the mold temperature during casting, the deeper the Si permeating and in the second layer the element Si could also be found

`Surface-Layer' momentum fluxes in nocturnal slope flows over steep terrain

NASA Astrophysics Data System (ADS)

Oldroyd, H. J.; Pardyjak, E.; Higgins, C. W.; Parlange, M. B.

2017-12-01

A common working definition for the `surface layer' is the lowest 10% of the atmospheric boundary layer (ABL) where the turbulent fluxes are essentially constant. The latter part of this definition is a critical assumption that must hold for accurate flux estimations from land-surface models, wall models, similarity theory, flux-gradient relations and bulk transfer methods. We present cases from observed momentum fluxes in nocturnal slope flows over steep (35.5 degree), alpine terrain in Val Ferret, Switzerland that satisfy the classical definitions of the surface layer and other cases where no traditional surface layer is observed. These cases broadly fall into two distinct flow regimes occurring under clear-sky conditions: (1) buoyancy-driven, `katabatic flow', characterized by an elevated velocity maximum (katabatic jet peak) and (2) `downslope winds', for which larger-scale forcing prevents formation of a katabatic jet. Velocity profiles in downslope wind cases are quite similar to logarithmic profiles typically observed over horizontal and homogeneous terrain, and the corresponding momentum fluxes roughly resemble a constant-flux surface-layer. Contrastingly, velocity profiles in the katabatic regime exhibit a jet-like shape. This jet strongly modulates the corresponding momentum fluxes, which exhibit strong gradients over the shallow katabatic layer and usually change sign near the jet peak, where the velocity gradients also change sign. However, a counter-gradient momentum flux is frequently observed near the jet peak (and sometimes at higher levels), suggesting strong non-local turbulent transport within the katabatic jet layer. We compare our observations with katabatic flow theories and observational studies over shallow-angle slopes and use co-spectral analyses to better identify and understand the non-local transport dynamics. Finally, we show that because of the counter-gradient momentum fluxes, surface layer stability and even local stability can be

A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes.

PubMed

He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

2016-08-26

Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them.

A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes

PubMed Central

He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

2016-01-01

Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them. PMID:27561546

Amorphous surface layers in Ti-implanted Fe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knapp, J.A.; Follstaedt, D.M.; Picraux, S.T.

1979-01-01

Implanting Ti into high-purity Fe results in an amorphous surface layer which is composed of not only Fe and Ti, but also C. Implantations were carried out at room temperature over the energy range 90 to 190 keV and fluence range 1 to 2 x 10/sup 16/ at/cm/sup 2/. The Ti-implanted Fe system has been characterized using transmission electron microscopy (TEM), ion backscattering and channeling analysis, and (d,p) nuclear reaction analysis. The amorphous layer was observed to form at the surface and grow inward with increasing Ti fluence. For an implant of 1 x 10/sup 17/ Ti/cm/sup 2/ at 180more » keV the layer thickness was 150 A, while the measured range of the implanted Ti was approx. 550 A. This difference is due to the incorporation of C into the amorphous alloy by C being deposited on the surface during implantation and subsequently diffusing into the solid. Our results indicate that C is an essential constituent of the amorphous phase for Ti concentrations less than or equal to 10 at. %. For the 1 x 10/sup 17/ Ti/cm/sup 2/ implant, the concentration of C in the amorphous phase was approx. 25 at. %, while that of Ti was only approx. 3 at. %. A higher fluence implant of 2 x 10/sup 17/ Ti/cm/sup 2/ produced an amorphous layer with a lower C concentration of approx. 10 at. % and a Ti concentration of approx. 20 at. %.« less

Automated airway evaluation system for multi-slice computed tomography using airway lumen diameter, airway wall thickness and broncho-arterial ratio

NASA Astrophysics Data System (ADS)

Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.; Lerallut, Jean-Francois

2006-03-01

Pulmonary diseases such as bronchiectasis, asthma, and emphysema are characterized by abnormalities in airway dimensions. Multi-slice computed tomography (MSCT) has become one of the primary means to depict these abnormalities, as the availability of high-resolution near-isotropic data makes it possible to evaluate airways at oblique angles to the scanner plane. However, currently, clinical evaluation of airways is typically limited to subjective visual inspection only: systematic evaluation of the airways to take advantage of high-resolution data has not proved practical without automation. We present an automated method to quantitatively evaluate airway lumen diameter, wall thickness and broncho-arterial ratios. In addition, our method provides 3D visualization of these values, graphically illustrating the location and extent of disease. Our algorithm begins by automatic airway segmentation to extract paths to the distal airways, and to create a map of airway diameters. Normally, airway diameters decrease as paths progress distally; failure to taper indicates abnormal dilatation. Our approach monitors airway lumen diameters along each airway path in order to detect abnormal profiles, allowing even subtle degrees of pathologic dilatation to be identified. Our method also systematically computes the broncho-arterial ratio at every terminal branch of the tree model, as a ratio above 1 indicates potentially abnormal bronchial dilatation. Finally, the airway wall thickness is computed at corresponding locations. These measurements are used to highlight abnormal branches for closer inspection, and can be summed to compute a quantitative global score for the entire airway tree, allowing reproducible longitudinal assessment of disease severity. Preliminary tests on patients diagnosed with bronchiectasis demonstrated rapid identification of lack of tapering, which also was confirmed by corresponding demonstration of elevated broncho-arterial ratios.

Steady Boundary Layer Disturbances Created By Two-Dimensional Surface Ripples

NASA Astrophysics Data System (ADS)

Kuester, Matthew

2017-11-01

Multiple experiments have shown that surface roughness can enhance the growth of Tollmien-Schlichting (T-S) waves in a laminar boundary layer. One of the common observations from these studies is a ``wall displacement'' effect, where the boundary layer profile shape remains relatively unchanged, but the origin of the profile pushes away from the wall. The objective of this work is to calculate the steady velocity field (including this wall displacement) of a laminar boundary layer over a surface with small, 2D surface ripples. The velocity field is a combination of a Blasius boundary layer and multiple disturbance modes, calculated using the linearized Navier-Stokes equations. The method of multiple scales is used to include non-parallel boundary layer effects of O (Rδ- 1) ; the non-parallel terms are necessary, because a wall displacement is mathematically inconsistent with a parallel boundary layer assumption. This technique is used to calculate the steady velocity field over ripples of varying height and wavelength, including cases where a separation bubble forms on the leeward side of the ripple. In future work, the steady velocity field will be the input for stability calculations, which will quantify the growth of T-S waves over rough surfaces. The author would like to acknowledge the support of the Kevin T. Crofton Aerospace & Ocean Engineering Department at Virginia Tech.

Surface morphological evolution of epitaxial CrN(001) layers

NASA Astrophysics Data System (ADS)

Frederick, J. R.; Gall, D.

2005-09-01

CrN layers, 57 and 230 nm thick, were grown on MgO(001) at Ts=600-800 °C by ultrahigh-vacuum magnetron sputter deposition in pure N2 discharges from an oblique deposition angle α=80°. Layers grown at 600 °C nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. The surface morphology of epitaxial CrN(001) grown at 700 °C is characterized by dendritic ridge patterns extending along the orthogonal <110> directions superposed by square-shaped super mounds with <100> edges. The ridge patterns are attributed to a Bales-Zangwill instability while the supermounds form due to atomic shadowing which leads to the formation of epitaxial inverted pyramids that are separated from the surrounding layer by tilted nanovoids. Growth at 800 °C yields complete single crystals with smooth surfaces. The root-mean-square surface roughness for 230-nm-thick layers decreases from 18.8 to 9.3 to 1.1 nm as Ts is raised from 600 to 700 to 800 °C. This steep decrease is due to a transition in the roughening mechanism from atomic shadowing to kinetic roughening. Atomic shadowing is dominant at 600 and 700 °C, where misoriented grains and supermounds, respectively, capture a larger fraction of the oblique deposition flux in comparison to the surrounding epitaxial matrix, resulting in a high roughening rate that is described by a power law with an exponent β>0.5. In contrast, kinetic roughening controls the surface morphology for Ts=800 °C, as well as the epitaxial fraction of the layers grown at 600 and 700 °C, yielding relatively smooth surfaces and β<=0.27.

An experimental investigation of turbulent boundary layers along curved surfaces

NASA Technical Reports Server (NTRS)

So, R. M. C.; Mellor, G. L.

1972-01-01

A curved wall tunnel was designed, and an equilibrium turbulent boundary layer was set up on the straight section preceding the curved test section. Turbulent boundary layer flows with uniform and adverse pressure distributions along convex and concave walls were investigated. Hot-wire measurements along the convex surface indicated that turbulent mixing between fluid layers was very much reduced. However, the law of the wall held and the skin friction, thus determined, correlated well with other measurements. Hot-wire measurements along the concave test wall revealed a system of longitudinal vortices inside the boundary layer and confirmed that concave curvature enhances mixing. A self-consistent set of turbulent boundary layer equations for flows along curved surfaces was derived together with a modified eddy viscosity. Solution of these equations together with the modified eddy viscosity gave results that correlated well with the present data on flows along the convex surface with arbitrary pressure distribution. However, it could only be used to predict the mean characteristics of the flow along concave walls because of the existence of the system of longitudinal vortices inside the boundary layer.

Enhanced magneto-optical imaging of internal stresses in the removed surface layer

NASA Astrophysics Data System (ADS)

Agalidi, Yuriy; Kozhukhar, Pavlo; Levyi, Sergii; Turbin, Dmitriy

2015-10-01

The paper describes a software method of reconstructing the state of the removed surface layer by visualising internal stresses in the underlying layers of the sample. Such a problem typically needs to be solved as part of forensic investigation that aims to reveal original marking of a sample with removed surface layer. For example, one may be interested in serial numbers of weapons or vehicles that had the surface layer of metal removed from the number plate. Experimental results of studying gradient internal stress fields in ferromagnetic sample using the NDI method of magneto-optical imaging (MOI) are presented. Numerical modelling results of internal stresses enclosed in the surface marking region are analysed and compared to the experimental results of magneto-optical imaging (MOI). MOI correction algorithm intended for reconstructing internal stress fields in the removed surface layer by extracting stresses retained by the underlying layers is described. Limiting ratios between parameters of a marking font are defined for the considered correction algorithm. Enhanced recognition properties for hidden stresses left by marking symbols are experimentally verified and confirmed.

Protective effects of valproic acid against airway hyperresponsiveness and airway remodeling in a mouse model of allergic airways disease.

PubMed

Royce, Simon G; Dang, William; Ververis, Katherine; De Sampayo, Nishika; El-Osta, Assam; Tang, Mimi L K; Karagiannis, Tom C

2011-12-01

Airway remodeling and airway hyperresponsiveness are major aspects of asthma pathology that are not targeted optimally by existing anti-inflammatory drugs. Histone deacetylase inhibitors have a wide range of effects that may potentially abrogate aspects of remodeling. One such histone deacetylase inhibitor is valproic acid (2-propylvaleric acid). Valproic acid is used clinically as an anti-epileptic drug and is a potent inhibitor of class I histone deacetylases but also inhibits class II histone deacetylases. We used valproic acid as a molecular model of histone deacetylase inhibition in vivo in chronic allergic airways disease mice with airway remodeling and airway hyperresponsiveness. Wild-type Balb/c mice with allergic airways disease were treated with valproic acid or vehicle control. Airway inflammation was assessed by bronchoalveolar lavage fluid cell counts and examination of lung tissue sections. Remodeling was assessed by morphometric analysis of histochemically stained slides and lung function was assessed by invasive plethysmography measurement of airway resistance. Valproic acid treatment did not affect inflammation parameters; however, valproic acid treatment resulted in reduced epithelial thickness as compared to vehicle treated mice (p < 0.01), reduced subepithelial collagen deposition (p < 0.05) and attenuated airway hyperresponsiveness (p < 0.05 and p < 0.01 for the two highest doses of methacholine, respectively). These findings show that treatment with valproic acid can reduce structural airway remodeling changes and hyperresponsiveness, providing further evidence for the potential use of histone deacetylase inhibitors for the treatment of asthma.

Computer graphic visualization of orbiter lower surface boundary-layer transition

NASA Technical Reports Server (NTRS)

Throckmorton, D. A.; Hartung, L. C.

1984-01-01

Computer graphic techniques are applied to the processing of Shuttle Orbiter flight data in order to create a visual presentation of the extent and movement of the boundary-layer transition front over the orbiter lower surface during entry. Flight-measured surface temperature-time histories define the onset and completion of the boundary-layer transition process at any measurement location. The locus of points which define the spatial position of the boundary-layer transition front on the orbiter planform is plotted at each discrete time for which flight data are available. Displaying these images sequentially in real-time results in an animated simulation of the in-flight boundary-layer transition process.

ZMappTM Reinforces the Airway Mucosal Barrier Against Ebola Virus.

PubMed

Yang, Bing; Schaefer, Alison; Wang, Ying-Ying; McCallen, Justin; Lee, Phoebe; Newby, Jay M; Arora, Harendra; Kumar, Priya A; Zeitlin, Larry; Whaley, Kevin J; McKinley, Scott A; Fischer, William A; Harit, Dimple; Lai, Samuel K

2018-04-24

Filoviruses, including Ebola, have the potential to be transmitted via virus-laden droplets deposited onto mucus membranes. Protecting against such emerging pathogens will require understanding how they may transmit at mucosal surfaces and developing strategies to reinforce the airway mucus barrier.Here, we prepared Ebola pseudovirus (with Zaire strain glycoproteins) and employed high resolution multiple particle tracking to track the motions of hundreds of individual pseudoviruses in fresh and undiluted human airway mucus isolated from extubated endotracheal tubes.We found that Ebola pseudovirus readily penetrate human airway mucus. Addition of ZMappTM, a cocktail of Ebola-binding IgG antibodies, effectively reduced mobility of Ebola pseudovirus in the same mucus secretions. Topical delivery of ZMappTM to the mouse airways also facilitated rapid elimination of Ebola pseudovirus.Our work demonstrates that antibodies can immobilize virions in airway mucus and reduce access to the airway epithelium, highlighting topical delivery of pathogen-specific antibodies to the lungs as a potential prophylactic or therapeutic approach against emerging viruses or biowarfare agents.

Airway stents

PubMed Central

Keyes, Colleen

2018-01-01

Stents and tubes to maintain the patency of the airways are commonly used for malignant obstruction and are occasionally employed in benign disease. Malignant airway obstruction usually results from direct involvement of bronchogenic carcinoma, or by extension of carcinomas occurring in the esophagus or the thyroid. External compression from lymph nodes or metastatic disease from other organs can also cause central airway obstruction. Most malignant airway lesions are surgically inoperable due to advanced disease stage and require multimodality palliation, including stent placement. As with any other medical device, stents have significantly evolved over the last 50 years and deserve an in-depth understanding of their true capabilities and complications. Not every silicone stent is created equal and the same holds for metallic stents. Herein, we present an overview of the topic as well as some of the more practical and controversial issues surrounding airway stents. We also try to dispel the myths surrounding stent removal and their supposed use only in central airways. At the end, we come to the long-held conclusion that stents should not be used as first line treatment of choice, but after ruling out the possibility of curative surgical resection or repair. PMID:29707506

Generation Mechanism of Work Hardened Surface Layer in Metal Cutting

NASA Astrophysics Data System (ADS)

Hikiji, Rikio; Kondo, Eiji; Kawagoishi, Norio; Arai, Minoru

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

Surface rheology of saponin adsorption layers.

PubMed

Stanimirova, R; Marinova, K; Tcholakova, S; Denkov, N D; Stoyanov, S; Pelan, E

2011-10-18

Extracts of the Quillaja saponaria tree contain natural surfactant molecules called saponins that very efficiently stabilize foams and emulsions. Therefore, such extracts are widely used in several technologies. In addition, saponins have demonstrated nontrivial bioactivity and are currently used as essential ingredients in vaccines, food supplements, and other health products. Previous preliminary studies showed that saponins have some peculiar surface properties, such as a very high surface modulus, that may have an important impact on the mechanisms of foam and emulsion stabilization. Here we present a detailed characterization of the main surface properties of highly purified aqueous extracts of Quillaja saponins. Surface tension isotherms showed that the purified Quillaja saponins behave as nonionic surfactants with a relatively high cmc (0.025 wt %). The saponin adsorption isotherm is described well by the Volmer equation, with an area per molecule of close to 1 nm(2). By comparing this area to the molecular dimensions, we deduce that the hydrophobic triterpenoid rings of the saponin molecules lie parallel to the air-water interface, with the hydrophilic glucoside tails protruding into the aqueous phase. Upon small deformation, the saponin adsorption layers exhibit a very high surface dilatational elasticity (280 ± 30 mN/m), a much lower shear elasticity (26 ± 15 mN/m), and a negligible true dilatational surface viscosity. The measured dilatational elasticity is in very good agreement with the theoretical predictions of the Volmer adsorption model (260 mN/m). The measured characteristic adsorption time of the saponin molecules is 4 to 5 orders of magnitude longer than that predicted theoretically for diffusion-controlled adsorption, which means that the saponin adsorption is barrier-controlled around and above the cmc. The perturbed saponin layers relax toward equilibrium in a complex manner, with several relaxation times, the longest of them being around 3

Layer-by-Layer Heparinization of the Cell Surface by Using Heparin-Binding Peptide Functionalized Human Serum Albumin.

PubMed

Song, Guowei; Hu, Yaning; Liu, Yusheng; Jiang, Rui

2018-05-20

Layer-by-layer heparinization of therapeutic cells prior to transplantation is an effective way to inhibit the instant blood-mediated inflammatory reactions (IBMIRs), which are the major cause of early cell graft loss during post-transplantation. Here, a conjugate of heparin-binding peptide (HBP) and human serum albumin (HSA), HBP-HSA, was synthesized by using heterobifunctional crosslinker. After the first heparin layer was coated on human umbilical vein endothelial cells (HUVECs) by means of the HBP-polyethylene glycol-phospholipid conjugate, HBP-HSA and heparin were then applied to the cell surface sequentially to form multiple layers. The immobilization and retention of heparin were analyzed by confocal microscopy and flow cytometry, respectively, and the cytotoxity of HBP-HSA was further evaluated by cell viability assay. Results indicated that heparin was successfully introduced to the cell surface in a layer-by-layer way and retained for at least 24 h, while the cytotoxity of HBP-HSA was negligible at the working concentration. Accordingly, this conjugate provides a promising method for co-immobilization of heparin and HSA to the cell surface under physiological conditions with improved biocompatibility.

Non-linear boundary-layer receptivity due to distributed surface roughness

NASA Technical Reports Server (NTRS)

Amer, Tahani Reffet

1995-01-01

The process by which a laminar boundary layer internalizes the external disturbances in the form of instability waves is known as boundary-layer receptivity. The objective of the present research was to determine the effect of acoustic excitation on boundary-layer receptivity for a flat plate with distributed variable-amplitude surface roughness through measurements with a hot-wire probe. Tollmien-Schlichting mode shapes due to surface roughness receptivity have also been determined, analyzed, and shown to be in agreement with theory and other experimental work. It has been shown that there is a linear relationship between the surface roughness and receptivity for certain roughness configurations with constant roughness wavelength. In addition, strong non-linear receptivity effects exist for certain surface roughness configurations over a band where the surface roughness and T-S wavelength are matched. The results from the present experiment follow the trends predicted by theory and other experimental work for linear receptivity. In addition, the results show the existence of non-linear receptivity effects for certain combinations of surface roughness elements.

Local small airway epithelial injury induces global smooth muscle contraction and airway constriction.

PubMed

Zhou, Jian; Alvarez-Elizondo, Martha B; Botvinick, Elliot; George, Steven C

2012-02-01

Small airway epithelial cells form a continuous sheet lining the conducting airways, which serves many functions including a physical barrier to protect the underlying tissue. In asthma, injury to epithelial cells can occur during bronchoconstriction, which may exacerbate airway hyperreactivity. To investigate the role of epithelial cell rupture in airway constriction, laser ablation was used to precisely rupture individual airway epithelial cells of small airways (<300-μm diameter) in rat lung slices (∼250-μm thick). Laser ablation of single epithelial cells using a femtosecond laser reproducibly induced airway contraction to ∼70% of the original cross-sectional area within several seconds, and the contraction lasted for up to 40 s. The airway constriction could be mimicked by mechanical rupture of a single epithelial cell using a sharp glass micropipette but not with a blunt glass pipette. These results suggest that soluble mediators released from the wounded epithelial cell induce global airway contraction. To confirm this hypothesis, the lysate of primary human small airway epithelial cells stimulated a similar airway contraction. Laser ablation of single epithelial cells triggered a single instantaneous Ca(2+) wave in the epithelium, and multiple Ca(2+) waves in smooth muscle cells, which were delayed by several seconds. Removal of extracellular Ca(2+) or decreasing intracellular Ca(2+) both blocked laser-induced airway contraction. We conclude that local epithelial cell rupture induces rapid and global airway constriction through release of soluble mediators and subsequent Ca(2+)-dependent smooth muscle shortening.

Virtual ellipsometry on layered micro-facet surfaces.

PubMed

Wang, Chi; Wilkie, Alexander; Harcuba, Petr; Novosad, Lukas

2017-09-18

Microfacet-based BRDF models are a common tool to describe light scattering from glossy surfaces. Apart from their wide-ranging applications in optics, such models also play a significant role in computer graphics for photorealistic rendering purposes. In this paper, we mainly investigate the computer graphics aspect of this technology, and present a polarisation-aware brute force simulation of light interaction with both single and multiple layered micro-facet surfaces. Such surface models are commonly used in computer graphics, but the resulting BRDF is ultimately often only approximated. Recently, there has been work to try to make these approximations more accurate, and to better understand the behaviour of existing analytical models. However, these brute force verification attempts still emitted the polarisation state of light and, as we found out, this renders them prone to mis-estimating the shape of the resulting BRDF lobe for some particular material types, such as smooth layered dielectric surfaces. For these materials, non-polarising computations can mis-estimate some areas of the resulting BRDF shape by up to 23%. But we also identified some other material types, such as dielectric layers over rough conductors, for which the difference turned out to be almost negligible. The main contribution of our work is to clearly demonstrate that the effect of polarisation is important for accurate simulation of certain material types, and that there are also other common materials for which it can apparently be ignored. As this required a BRDF simulator that we could rely on, a secondary contribution is that we went to considerable lengths to validate our software. We compare it against a state-of-art model from graphics, a library from optics, and also against ellipsometric measurements of real surface samples.

Atopic asthmatic immune phenotypes associated with airway microbiota and airway obstruction.

PubMed

Turturice, Benjamin A; McGee, Halvor S; Oliver, Brian; Baraket, Melissa; Nguyen, Brian T; Ascoli, Christian; Ranjan, Ravi; Rani, Asha; Perkins, David L; Finn, Patricia W

2017-01-01

Differences in asthma severity may be related to inflammation in the airways. The lower airway microbiota has been associated with clinical features such as airway obstruction, symptom control, and response to corticosteroids. To assess the relationship between local airway inflammation, severity of disease, and the lower airway microbiota in atopic asthmatics. A cohort of young adult, atopic asthmatics with intermittent or mild/moderate persistent symptoms (n = 13) were assessed via bronchoscopy, lavage, and spirometry. These individuals were compared to age matched non-asthmatic controls (n = 6) and to themselves after six weeks of treatment with fluticasone propionate (FP). Inflammation of the airways was assessed via a cytokine and chemokine panel. Lower airway microbiota composition was determined by metagenomic shotgun sequencing. Unsupervised clustering of cytokines and chemokines prior to treatment with FP identified two asthmatic phenotypes (AP), termed AP1 and AP2, with distinct bronchoalveolar lavage inflammatory profiles. AP2 was associated with more obstruction, compared to AP1. After treatment with FP reduced MIP-1β and TNF-α and increased IL-2 was observed. A module of highly correlated cytokines that include MIP-1β and TNF-α was identified that negatively correlated with pulmonary function. Independently, IL-2 was positively correlated with pulmonary function. The airway microbiome composition correlated with asthmatic phenotypes. AP2, prior to FP treatment, was enriched with Streptococcus pneumoniae. Unique associations between IL-2 or the cytokine module and the microbiota composition of the airways were observed in asthmatics subjects prior to treatment but not after or in controls. The underlying inflammation in atopic asthma is related to the composition of microbiota and is associated with severity of airway obstruction. Treatment with inhaled corticosteroids was associated with changes in the airway inflammatory response to microbiota.

Stormwater infiltration and surface runoff pollution reduction performance of permeable pavement layers.

PubMed

Niu, Zhi-Guang; Lv, Zhi-Wei; Zhang, Ying; Cui, Zhen-Zhen

2016-02-01

In this paper, the laboratory-scale permeable pavement layers, including a surface permeable brick layer, coarse sand bedding layers (thicknesses = 2, 3.5, and 5 cm), and single-graded gravel sub-base layers (thicknesses = 15, 20, 25, and 30 cm), were built to evaluate stormwater infiltration and surface runoff pollution reduction performance. And, the infiltration rate (I) and concentrations of suspended solids (SS), total phosphorus (TP), chemical oxygen demand (COD), ammonia nitrogen, and total nitrogen (TN) were measured under the simulated rainfall intensity of 72.4 mm/h over duration of 60 min. The results indicate that the thickness factor primarily influences the infiltration rate and pollutant removal rate. The highest steady infiltration rate was for surface brick layer 51.0 mm/h, for 5-cm sand bedding layer 32.3 mm/h, and for 30-cm gravel sub-base layer 42.3 mm/h, respectively. The SS average removal rate was relative higher (79.8 ∼ 98.6 %) for all layers due to the interception and filtration. The average removal rates of TP and COD were for surface layer 71.2 and 24.1 %, for 5-cm bedding layer 54.8 and 9.0 %, and for 20-cm sub-base layer 72.2 and 26.1 %. Ammonia nitrogen and TN cannot steadily be removed by layers according to the experiment results. The optimal thickness of bedding sands was 5 cm, and that of sub-base gravels was 20 ∼ 30 cm.

Magnetomechanical effect in silicon (Cz-Si) surface layers

NASA Astrophysics Data System (ADS)

Koplak, O. V.; Dmitriev, A. I.; Morgunov, R. B.

2012-07-01

The mechanical properties of near-surface layers of Czochralski-grown silicon crystals Cz- n-Si(111) have been found to undergo changes in response to an external constant magnetic field ( B ˜ 0.1 T). A magnetically induced variation in the microhardness, Young's modulus, and coefficient of plasticity of silicon crystals correlates with the change in the lattice parameter and internal stresses of the sample. The growth of an oxide film under exposure to a magnetic field plays the principal role in the magnetomechanical effect due to a decrease in the concentration of oxygen complexes in the near-surface layers of the sample. In microstructured silicon, where the surface is considerably more developed, the magnetic field induces more profound changes in the internal stresses as compared to single crystals.

Displacement energy of the surface layers of tungsten

NASA Astrophysics Data System (ADS)

Han, Longtao; Krstic, Predrag

2015-11-01

A molecular dynamics study with BOP potential is used to calculate the threshold displacement energy (ED) of primary knock-on atoms in the surface layers of the tungsten bcc crystal lattice at 300 K and at various crystallographic directions. Depending on the direction, ED is 10% to 75% smaller from the bulk value at the first layer, interfacing vacuum, while it reaches close to the bulk value already at the third tungsten layer. Supported by IACS of SBU and LDRD of PPPL.

Near Surface Vapor Bubble Layers in Buoyant Low Stretch Burning of Polymethylmethacrylate

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Tien, J. S.

1999-01-01

Large-scale buoyant low stretch stagnation point diffusion flames over solid fuel (polymethylmethacrylate) were studied for a range of aerodynamic stretch rates of 2-12/ sec which are of the same order as spacecraft ventilation-induced stretch in a microgravity environment. An extensive layer of polymer material above the glass transition temperature is observed. Unique phenomena associated with this extensive glass layer included substantial swelling of the burning surface, in-depth bubble formation, and migration and/or elongation of the bubbles normal to the hot surface. The bubble layer acted to insulate the polymer surface by reducing the effective conductivity of the solid. The reduced in-depth conduction stabilized the flame for longer than expected from theory neglecting the bubble layer. While buoyancy acts to move the bubbles deeper into the molten polymer, thermocapillary forces and surface regression both act to bring the bubbles to the burning surface. Bubble layers may thus be very important in low gravity (low stretch) burning of materials. As bubbles reached the burning surface, monomer fuel vapors jetted from the surface, enhancing burning by entraining ambient air flow. Popping of these bubbles at the surface can expel burning droplets of the molten material, which may increase the fire propagation hazards at low stretch rates.

The effects of spatial inhomogeneities on flow through the endothelial surface layer.

PubMed

Leiderman, Karin M; Miller, Laura A; Fogelson, Aaron L

2008-05-21

Flow through the endothelial surface layer (the glycocalyx and adsorbed plasma proteins) plays an important but poorly understood role in cell signaling through a process known as mechanotransduction. Characterizing the flow rates and shear stresses throughout this layer is critical for understanding how flow-induced ionic currents, deformations of transmembrane proteins, and the convection of extracellular molecules signal biochemical events within the cell, including cytoskeletal rearrangements, gene activation, and the release of vasodilators. Previous mathematical models of flow through the endothelial surface layer are based upon the assumptions that the layer is of constant hydraulic permeability and constant height. These models also assume that the layer is continuous across the endothelium and that the layer extends into only a small portion of the vessel lumen. Results of these models predict that fluid shear stress is dissipated through the surface layer and is thus negligible near endothelial cell membranes. In this paper, such assumptions are removed, and the resultant flow rates and shear stresses through the layer are described. The endothelial surface layer is modeled as clumps of a Brinkman medium immersed in a Newtonian fluid. The width and spacing of each clump, hydraulic permeability, and fraction of the vessel lumen occupied by the layer are varied. The two-dimensional Navier-Stokes equations with an additional Brinkman resistance term are solved using a projection method. Several fluid shear stress transitions in which the stress at the membrane shifts from low to high values are described. These transitions could be significant to cell signaling since the endothelial surface layer is likely dynamic in its composition, density, and height.

Degrees of reality: airway anatomy of high-fidelity human patient simulators and airway trainers.

PubMed

Schebesta, Karl; Hüpfl, Michael; Rössler, Bernhard; Ringl, Helmut; Müller, Michael P; Kimberger, Oliver

2012-06-01

Human patient simulators and airway training manikins are widely used to train airway management skills to medical professionals. Furthermore, these patient simulators are employed as standardized "patients" to evaluate airway devices. However, little is known about how realistic these patient simulators and airway-training manikins really are. This trial aimed to evaluate the upper airway anatomy of four high-fidelity patient simulators and two airway trainers in comparison with actual patients by means of radiographic measurements. The volume of the pharyngeal airspace was the primary outcome parameter. Computed tomography scans of 20 adult trauma patients without head or neck injuries were compared with computed tomography scans of four high-fidelity patient simulators and two airway trainers. By using 14 predefined distances, two cross-sectional areas and three volume parameters of the upper airway, the manikins' similarity to a human patient was assessed. The pharyngeal airspace of all manikins differed significantly from the patients' pharyngeal airspace. The HPS Human Patient Simulator (METI®, Sarasota, FL) was the most realistic high-fidelity patient simulator (6/19 [32%] of all parameters were within the 95% CI of human airway measurements). The airway anatomy of four high-fidelity patient simulators and two airway trainers does not reflect the upper airway anatomy of actual patients. This finding may impact airway training and confound comparative airway device studies.

Local small airway epithelial injury induces global smooth muscle contraction and airway constriction

PubMed Central

Zhou, Jian; Alvarez-Elizondo, Martha B.; Botvinick, Elliot

2012-01-01

Small airway epithelial cells form a continuous sheet lining the conducting airways, which serves many functions including a physical barrier to protect the underlying tissue. In asthma, injury to epithelial cells can occur during bronchoconstriction, which may exacerbate airway hyperreactivity. To investigate the role of epithelial cell rupture in airway constriction, laser ablation was used to precisely rupture individual airway epithelial cells of small airways (<300-μm diameter) in rat lung slices (∼250-μm thick). Laser ablation of single epithelial cells using a femtosecond laser reproducibly induced airway contraction to ∼70% of the original cross-sectional area within several seconds, and the contraction lasted for up to 40 s. The airway constriction could be mimicked by mechanical rupture of a single epithelial cell using a sharp glass micropipette but not with a blunt glass pipette. These results suggest that soluble mediators released from the wounded epithelial cell induce global airway contraction. To confirm this hypothesis, the lysate of primary human small airway epithelial cells stimulated a similar airway contraction. Laser ablation of single epithelial cells triggered a single instantaneous Ca2+ wave in the epithelium, and multiple Ca2+ waves in smooth muscle cells, which were delayed by several seconds. Removal of extracellular Ca2+ or decreasing intracellular Ca2+ both blocked laser-induced airway contraction. We conclude that local epithelial cell rupture induces rapid and global airway constriction through release of soluble mediators and subsequent Ca2+-dependent smooth muscle shortening. PMID:22114176

Airway reopening: Steadily propagating bubbles in buckled elastic tubes

NASA Astrophysics Data System (ADS)

Heil, Matthias; Hazel, Andrew L.

2001-11-01

Many pulmonary diseases result in the collapse and occlusion of parts of the lung by viscous fluid. The subsequent airway reopening is generally assumed to occur via the propagation of an air finger into the collapsed, fluid-filled part of the airway. The problem has some similarity to the scenario of the `first breath' when air has to enter the fluid-filled lungs of a newborn baby for the first time. We have developed the first three-dimensional computational model of airway reopening, based on a finite-element solution of the free-surface Stokes equations, fully coupled to the equations of large-displacement shell theory. Following a brief discussion of the numerical method, we will present results that illustrate the 3D flow field by which the steadily propagating air finger reopens the non-axisymmetrically collapsed airway. Finally, we will contrast the system's behaviour to predictions from earlier two-dimensional models.

Structural features of the adsorption layer of pentacene on the graphite surface and the PMMA/graphite hybrid surface

NASA Astrophysics Data System (ADS)

Fadeeva, A. I.; Gorbunov, V. A.; Litunenko, T. A.

2017-08-01

Using the molecular dynamics and the Monte Carlo methods, we have studied the structural features and growth mechanism of the pentacene film on graphite and polymethylmethacrylate /graphite surfaces. Monolayer capacity and molecular area, optimal angles between the pentacene molecules and graphite and PMMA/graphite surfaces as well as the characteristic angles between the neighboring pentacene molecules in the adsorption layer were estimated. It is shown that the orientation of the pentacene molecules in the film is determined by a number of factors, including the surface concentration of the molecules, relief of the surface, presence or absence of the polymer layer and its thickness. The pentacene molecules adsorbed on the graphite surface keep a horizontal position relative to the long axis at any surface coverage/thickness of the film. In the presence of the PMMA layer on the graphite, the increase of the number of pentacene molecules as well as the thickness of the PMMA layer induce the change of molecular orientation from predominantly horizontal to vertical one. The reason for such behavior is supposed to be the roughness of the PMMA surface.

Elastic layer under axisymmetric indentation and surface energy effects

NASA Astrophysics Data System (ADS)

Intarit, Pong-in; Senjuntichai, Teerapong; Rungamornrat, Jaroon

2018-04-01

In this paper, a continuum-based approach is adopted to investigate the contact problem of an elastic layer with finite thickness and rigid base subjected to axisymmetric indentation with the consideration of surface energy effects. A complete Gurtin-Murdoch surface elasticity is employed to consider the influence of surface stresses. The indentation problem of a rigid frictionless punch with arbitrary axisymmetric profiles is formulated by employing the displacement Green's functions, derived with the aid of Hankel integral transform technique. The problem is solved by assuming the contact pressure distribution in terms of a linear combination of admissible functions and undetermined coefficients. Those coefficients are then obtained by employing a collocation technique and an efficient numerical quadrature scheme. The accuracy of proposed solution technique is verified by comparing with existing solutions for rigid indentation on an elastic half-space. Selected numerical results for the indenters with flat-ended cylindrical and paraboloidal punch profiles are presented to portray the influence of surface energy effects on elastic fields of the finite layer. It is found that the presence of surface stresses renders the layer stiffer, and the size-dependent behavior of elastic fields is observed in the present solutions. In addition, the surface energy effects become more pronounced with smaller contact area; thus, the influence of surface energy cannot be ignored in the analysis of indentation problem especially when the indenter size is very small such as in the case of nanoindentation.

Parasympathetic Control of Airway Submucosal Glands: Central Reflexes and the Airway Intrinsic Nervous System

PubMed Central

Wine, Jeffrey J.

2007-01-01

Airway submucosal glands produce the mucus that lines the upper airways to protect them against insults. This review summarizes evidence for two forms of gland secretion, and hypothesizes that each is mediated by different but partially overlapping neural pathways. Airway innate defense comprises low level gland secretion, mucociliary clearance and surveillance by airway-resident phagocytes to keep the airways sterile in spite of nearly continuous inhalation of low levels of pathogens. Gland secretion serving innate defense is hypothesized to be under the control of intrinsic (peripheral) airway neurons and local reflexes, and these may depend disproportionately on non-cholinergic mechanisms, with most secretion being produced by VIP and tachykinins. In the genetic disease cystic fibrosis, airway glands no longer secrete in response to VIP alone and fail to show the synergy between VIP, tachykinins and ACh that is observed in normal glands. The consequent crippling of the submucosal gland contribution to innate defense may be one reason that cystic fibrosis airways are infected by mucus-resident bacteria and fungi that are routinely cleared from normal airways. By contrast, the acute (emergency) airway defense reflex is centrally mediated by vagal pathways, is primarily cholinergic, and stimulates copious volumes of gland mucus in response to acute, intense challenges to the airways, such as those produced by very vigorous exercise or aspiration of foreign material. In cystic fibrosis, the acute airway defense reflex can still stimulate the glands to secrete large amounts of mucus, although its properties are altered. Importantly, treatments that recruit components of the acute reflex, such as inhalation of hypertonic saline, are beneficial in treating cystic fibrosis airway disease. The situation for recipients of lung transplants is the reverse; transplanted airways retain the airway intrinsic nervous system but lose centrally mediated reflexes. The consequences

Compositions of surface layers formed on amalgams in air, water, and saline.

PubMed

Hanawa, T; Gnade, B E; Ferracane, J L; Okabe, T; Watari, F

1993-12-01

The surface layers formed on both a zinc-free and a zinc-containing dental amalgam after polishing and aging in air, water, or saline, were characterized using x-ray photoelectron spectroscopy (XPS) to determine the compositions of the surface layers which might govern the release of mercury from amalgam. The XPS data revealed that the formation of the surface layer on the zinc-containing amalgam was affected by the environment in which the amalgam was polished and aged, whereas that on the zinc-free amalgam was not affected. In addition, among the elements contained in amalgam, zinc was the most reactive with the environment, and was preferentially dissolved from amalgam into water or saline. Mercury atoms existed in the metallic state in the surface layer.

Thermocapillary convection in two immiscible liquid layers with free surface

NASA Technical Reports Server (NTRS)

Doi, Takao; Koster, Jean N.

1993-01-01

Thermocapillary convection is studied in two immiscible liquid layers with one free surface, one liquid/liquid interface, and differential heating applied parallel to the interfaces. An analytical solution is introduced for infinite horizontal layers. The defining parameter for the flow pattern is lambda, the ratio of the temperature coefficient of the interfacial tension to that of the surface tension. Four different flow patterns exist under zero gravity conditions. 'Halt' conditions which halt the fluid motion in the lower encapsulated liquid layer have been found. A numerical experiment is carried out to study effects of vertical end walls on the double layer convection in a 2D cavity. The halt condition obtained from the analytical study is found to be valid in the limit of small Reynolds numbers. The flow in the encapsulated liquid layer can be suppressed substantially.

Airway mucus, inflammation and remodeling: emerging links in the pathogenesis of chronic lung diseases.

PubMed

Zhou-Suckow, Zhe; Duerr, Julia; Hagner, Matthias; Agrawal, Raman; Mall, Marcus A

2017-03-01

Airway mucus obstruction is a hallmark of many chronic lung diseases including rare genetic disorders such as cystic fibrosis (CF) and primary ciliary dyskinesia, as well as common lung diseases such as asthma and chronic obstructive pulmonary disease (COPD), which have emerged as a leading cause of morbidity and mortality worldwide. However, the role of excess airway mucus in the in vivo pathogenesis of these diseases remains poorly understood. The generation of mice with airway-specific overexpression of epithelial Na + channels (ENaC), exhibiting airway surface dehydration (mucus hyperconcentration), impaired mucociliary clearance (MCC) and mucus plugging, led to a model of muco-obstructive lung disease that shares key features of CF and COPD. In this review, we summarize recent progress in the understanding of causes of impaired MCC and in vivo consequences of airway mucus obstruction that can be inferred from studies in βENaC-overexpressing mice. These studies confirm that mucus hyperconcentration on airway surfaces plays a critical role in the pathophysiology of impaired MCC, mucus adhesion and airway plugging that cause airflow obstruction and provide a nidus for bacterial infection. In addition, these studies support the emerging concept that excess airway mucus per se, probably via several mechanisms including hypoxic epithelial necrosis, retention of inhaled irritants or allergens, and potential immunomodulatory effects, is a potent trigger of chronic airway inflammation and associated lung damage, even in the absence of bacterial infection. Finally, these studies suggest that improvement of mucus clearance may be a promising therapeutic strategy for a spectrum of muco-obstructive lung diseases.

Surface passivation investigation on ultra-thin atomic layer deposited aluminum oxide layers for their potential application to form tunnel layer passivated contacts

NASA Astrophysics Data System (ADS)

Xin, Zheng; Ling, Zhi Peng; Nandakumar, Naomi; Kaur, Gurleen; Ke, Cangming; Liao, Baochen; Aberle, Armin G.; Stangl, Rolf

2017-08-01

The surface passivation performance of atomic layer deposited ultra-thin aluminium oxide layers with different thickness in the tunnel layer regime, i.e., ranging from one atomic cycle (∼0.13 nm) to 11 atomic cycles (∼1.5 nm) on n-type silicon wafers is studied. The effect of thickness and thermal activation on passivation performance is investigated with corona-voltage metrology to measure the interface defect density D it(E) and the total interface charge Q tot. Furthermore, the bonding configuration variation of the AlO x films under various post-deposition thermal activation conditions is analyzed by Fourier transform infrared spectroscopy. Additionally, poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) is used as capping layer on ultra-thin AlO x tunneling layers to further reduce the surface recombination current density to values as low as 42 fA/cm2. This work is a useful reference for using ultra-thin ALD AlO x layers as tunnel layers in order to form hole selective passivated contacts for silicon solar cells.

Sensory neuropeptides and the human lower airways: present state and future directions.

PubMed

Joos, G F; Germonpre, P R; Kips, J C; Peleman, R A; Pauwels, R A

1994-06-01

The sensory neuropeptides, substance P and neurokinin A, are present in human airway nerves, beneath and within the epithelium, around blood vessels and submucosal glands, and within the bronchial smooth muscle layer. Studies on autopsy tissue, bronchoalveolar lavage and sputum suggest that in asthma the substance P content of the airways may be increased. Neurokinin A is a more potent bronchoconstrictor than substance P. Asthmatics are hyperresponsive to neurokinin A and substance P. The neuropeptide degrading enzyme, neutral endopeptidase is present in the airways and is involved in the degradation of endogenously released and exogenously administered substance P and neurokinin A, both in normal and asthmatic subjects. As for other indirect bronchoconstrictor stimuli, the effect of neurokinin A on airway calibre in asthmatics can be inhibited by pretreatment with nedocromil sodium. Evidence is accumulating, not only from studies in animals but also from experiments on human airways, that tachykinins may also cause mucus secretion and plasma extravasation. They also have important proinflammatory effects, such as the chemoattraction of eosinophils and neutrophils, the adhesion of neutrophils, and the stimulation of lymphocytes, macrophages and mast cells. The tachykinins interact with the targets on the airways by specific tachykinin receptors. The NK1 and the NK2 receptor have been characterized in human airways, both pharmacologically and by cloning. The NK2 receptor is responsible for the in vitro contraction of normal airways, whilst the NK1 receptor is responsible for most of the other airway effects. Because of their presence in the airways and because of their ability to mimic the various pathophysiological features of asthma, substance P and neurokinin A are presently considered as possible mediators of asthma. The present development of potent and selective tachykinin antagonists will allow us to further define the role of tachykinins in the pathogenesis

Ventilation heterogeneity is a major determinant of airway hyperresponsiveness in asthma, independent of airway inflammation

PubMed Central

Downie, Sue R; Salome, Cheryl M; Verbanck, Sylvia; Thompson, Bruce; Berend, Norbert; King, Gregory G

2007-01-01

Background Airway hyperresponsiveness is the ability of airways to narrow excessively in response to inhaled stimuli and is a key feature of asthma. Airway inflammation and ventilation heterogeneity have been separately shown to be associated with airway hyperresponsiveness. A study was undertaken to establish whether ventilation heterogeneity is associated with airway hyperresponsiveness independently of airway inflammation in subjects with asthma and to determine the effect of inhaled corticosteroids on this relationship. Methods Airway inflammation was measured in 40 subjects with asthma by exhaled nitric oxide, ventilation heterogeneity by multiple breath nitrogen washout and airway hyperresponsiveness by methacholine challenge. In 18 of these subjects with uncontrolled symptoms, measurements were repeated after 3 months of treatment with inhaled beclomethasone dipropionate. Results At baseline, airway hyperresponsiveness was independently predicted by airway inflammation (partial r2 = 0.20, p<0.001) and ventilation heterogeneity (partial r2 = 0.39, p<0.001). Inhaled corticosteroid treatment decreased airway inflammation (p = 0.002), ventilation heterogeneity (p = 0.009) and airway hyperresponsiveness (p<0.001). After treatment, ventilation heterogeneity was the sole predictor of airway hyperresponsiveness (r2 = 0.64, p<0.001). Conclusions Baseline ventilation heterogeneity is a strong predictor of airway hyperresponsiveness, independent of airway inflammation in subjects with asthma. Its persistent relationship with airway hyperresponsiveness following anti‐inflammatory treatment suggests that it is an important independent determinant of airway hyperresponsiveness. Normalisation of ventilation heterogeneity is therefore a potential goal of treatment that may lead to improved long‐term outcomes. PMID:17311839

Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO2.

PubMed

Gasvoda, Ryan J; van de Steeg, Alex W; Bhowmick, Ranadeep; Hudson, Eric A; Agarwal, Sumit

2017-09-13

Surface phenomena during atomic layer etching (ALE) of SiO 2 were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF x ) film deposition and Ar plasma activation of the CF x film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF x deposition half-cycle from a C 4 F 8 /Ar plasma show that an atomically thin mixing layer is formed between the deposited CF x layer and the underlying SiO 2 film. Etching during the Ar plasma cycle is activated by Ar + bombardment of the CF x layer, which results in the simultaneous removal of surface CF x and the underlying SiO 2 film. The interfacial mixing layer in ALE is atomically thin due to the low ion energy during CF x deposition, which combined with an ultrathin CF x layer ensures an etch rate of a few monolayers per cycle. In situ ellipsometry shows that for a ∼4 Å thick CF x film, ∼3-4 Å of SiO 2 was etched per cycle. However, during the Ar plasma half-cycle, etching proceeds beyond complete removal of the surface CF x layer as F-containing radicals are slowly released into the plasma from the reactor walls. Buildup of CF x on reactor walls leads to a gradual increase in the etch per cycle.

Layer Protecting the Surface of Zirconium Used in Nuclear Reactors.

PubMed

Ashcheulov, Petr; Skoda, Radek; Skarohlíd, Jan; Taylor, Andrew; Fendrych, Frantisek; Kratochvílová, Irena

2016-01-01

Zirconium alloys have very useful properties for nuclear facilities applications having low absorption cross-section of thermal electrons, high ductility, hardness and corrosion resistance. However, there is also a significant disadvantage: it reacts with water steam and during this (oxidative) reaction it releases hydrogen gas, which partly diffuses into the alloy forming zirconium hydrides. A new strategy for surface protection of zirconium alloys against undesirable oxidation in nuclear reactors by polycrystalline diamond film has been patented- Czech patent 305059: Layer protecting the surface of zirconium alloys used in nuclear reactors and PCT patent: Layer for protecting surface of zirconium alloys (Patent Number: WO2015039636-A1). The zirconium alloy surface was covered by polycrystalline diamond layer grown in plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. Substantial progress in the description and understanding of the polycrystalline diamond/ zirconium alloys interface and material properties under standard and nuclear reactors conditions (irradiation, hot steam oxidation experiments and heating-quenching cycles) was made. In addition, process technology for the deposition of protective polycrystalline diamond films onto the surface of zirconium alloys was optimized. Zircaloy2 nuclear fuel pins were covered by 300 nm thick protective polycrystalline diamond layer (PCD) using plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. The polycrystalline diamond layer protects the zirconium alloy surface against undesirable oxidation and consolidates its chemical stability while preserving its functionality. PCD covered Zircaloy2 and standard Zircaloy2 pins were for 30 min. oxidized in 1100°C hot steam. Under these conditions α phase of zirconium changes to β phase (more opened for oxygen/hydrogen diffusion). PCD anticorrosion protection of Zircaloy nuclear fuel assemblies can

Optical transparency of graphene layers grown on metal surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rut’kov, E. V.; Lavrovskaya, N. P.; Sheshenya, E. S., E-mail: sheshenayket@gmail.ru

It is shown that, in contradiction with the fundamental results obtained for free graphene, graphene films grown on the Rh(111) surface to thicknesses from one to ~(12–15) single layers do not absorb visible electromagnetic radiation emitted from the surface and influence neither the brightness nor true temperature of the sample. At larger thicknesses, such absorption occurs. This effect is observed for the surfaces of other metals, specifically, Pt(111), Re(1010), and Ni(111) and, thus, can be considered as being universal. It is thought that the effect is due to changes in the electronic properties of thin graphene layers because of electronmore » transfer between graphene and the metal substrate.« less

A hybrid method for airway segmentation and automated measurement of bronchial wall thickness on CT.

PubMed

Xu, Ziyue; Bagci, Ulas; Foster, Brent; Mansoor, Awais; Udupa, Jayaram K; Mollura, Daniel J

2015-08-01

Inflammatory and infectious lung diseases commonly involve bronchial airway structures and morphology, and these abnormalities are often analyzed non-invasively through high resolution computed tomography (CT) scans. Assessing airway wall surfaces and the lumen are of great importance for diagnosing pulmonary diseases. However, obtaining high accuracy from a complete 3-D airway tree structure can be quite challenging. The airway tree structure has spiculated shapes with multiple branches and bifurcation points as opposed to solid single organ or tumor segmentation tasks in other applications, hence, it is complex for manual segmentation as compared with other tasks. For computerized methods, a fundamental challenge in airway tree segmentation is the highly variable intensity levels in the lumen area, which often causes a segmentation method to leak into adjacent lung parenchyma through blurred airway walls or soft boundaries. Moreover, outer wall definition can be difficult due to similar intensities of the airway walls and nearby structures such as vessels. In this paper, we propose a computational framework to accurately quantify airways through (i) a novel hybrid approach for precise segmentation of the lumen, and (ii) two novel methods (a spatially constrained Markov random walk method (pseudo 3-D) and a relative fuzzy connectedness method (3-D)) to estimate the airway wall thickness. We evaluate the performance of our proposed methods in comparison with mostly used algorithms using human chest CT images. Our results demonstrate that, on publicly available data sets and using standard evaluation criteria, the proposed airway segmentation method is accurate and efficient as compared with the state-of-the-art methods, and the airway wall estimation algorithms identified the inner and outer airway surfaces more accurately than the most widely applied methods, namely full width at half maximum and phase congruency. Copyright © 2015. Published by Elsevier B.V.

Evidence of a Transition Layer between the Free Surface and the Bulk.

PubMed

Ogieglo, Wojciech; Tempelman, Kristianne; Napolitano, Simone; Benes, Nieck E

2018-03-15

The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

Thermocouple Rakes for Measuring Boundary Layer Flows Extremely Close to Surface

NASA Technical Reports Server (NTRS)

Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Blaha, Charles A.

2001-01-01

Of vital interest to aerodynamic researchers is precise knowledge of the flow velocity profile next to the surface. This information is needed for turbulence model development and the calculation of viscous shear force. Though many instruments can determine the flow velocity profile near the surface, none of them can make measurements closer than approximately 0.01 in. from the surface. The thermocouple boundary-layer rake can measure much closer to the surface than conventional instruments can, such as a total pressure boundary layer rake, hot wire, or hot film. By embedding the sensors (thermocouples) in the region where the velocity is equivalent to the velocity ahead of a constant thickness strut, the boundary-layer flow profile can be obtained. The present device fabricated at the NASA Glenn Research Center microsystem clean room has a heater made of platinum and thermocouples made of platinum and gold. Equal numbers of thermocouples are placed both upstream and downstream of the heater, so that the voltage generated by each pair at the same distance from the surface is indicative of the difference in temperature between the upstream and downstream thermocouple locations. This voltage differential is a function of the flow velocity, and like the conventional total pressure rake, it can provide the velocity profile. In order to measure flow extremely close to the surface, the strut is made of fused quartz with extremely low heat conductivity. A large size thermocouple boundary layer rake is shown in the following photo. The latest medium size sensors already provide smooth velocity profiles well into the boundary layer, as close as 0.0025 in. from the surface. This is about 4 times closer to the surface than the previously used total pressure rakes. This device also has the advantage of providing the flow profile of separated flow and also it is possible to measure simultaneous turbulence levels within the boundary layer.

Extending the Diffuse Layer Model of Surface Acidity Constant Behavior: IV. Diffuse Layer Charge/Potential Relationships

EPA Science Inventory

Most current electrostatic surface complexation models describing ionic binding at the particle/water interface rely on the use of Poisson - Boltzmann (PB) theory for relating diffuse layer charge densities to diffuse layer electrostatic potentials. PB theory is known to contain ...

Parasympathetic control of airway submucosal glands: central reflexes and the airway intrinsic nervous system.

PubMed

Wine, Jeffrey J

2007-04-30

Airway submucosal glands produce the mucus that lines the upper airways to protect them against insults. This review summarizes evidence for two forms of gland secretion, and hypothesizes that each is mediated by different but partially overlapping neural pathways. Airway innate defense comprises low level gland secretion, mucociliary clearance and surveillance by airway-resident phagocytes to keep the airways sterile in spite of nearly continuous inhalation of low levels of pathogens. Gland secretion serving innate defense is hypothesized to be under the control of intrinsic (peripheral) airway neurons and local reflexes, and these may depend disproportionately on non-cholinergic mechanisms, with most secretion being produced by VIP and tachykinins. In the genetic disease cystic fibrosis, airway glands no longer secrete in response to VIP alone and fail to show the synergy between VIP, tachykinins and ACh that is observed in normal glands. The consequent crippling of the submucosal gland contribution to innate defense may be one reason that cystic fibrosis airways are infected by mucus-resident bacteria and fungi that are routinely cleared from normal airways. By contrast, the acute (emergency) airway defense reflex is centrally mediated by vagal pathways, is primarily cholinergic, and stimulates copious volumes of gland mucus in response to acute, intense challenges to the airways, such as those produced by very vigorous exercise or aspiration of foreign material. In cystic fibrosis, the acute airway defense reflex can still stimulate the glands to secrete large amounts of mucus, although its properties are altered. Importantly, treatments that recruit components of the acute reflex, such as inhalation of hypertonic saline, are beneficial in treating cystic fibrosis airway disease. The situation for recipients of lung transplants is the reverse; transplanted airways retain the airway intrinsic nervous system but lose centrally mediated reflexes. The consequences

Measurements of surface layer of the articular cartilage using microscopic techniques

NASA Astrophysics Data System (ADS)

Ryniewicz, A. M.; Ryniewicz, A.; Ryniewicz, W.; Gaska, A.

2010-07-01

The articular cartilage is the structure that directly cooperates tribologically in biobearing. It belongs to the connective tissues and in the joints it assumes two basic forms: hyaline cartilage that builds joint surfaces and fibrocartilage which may create joint surfaces. From this fibrocartilage are built semilunar cartilage and joint disc are built as well. The research of articular cartilage have been done in macro, micro and nano scale. In all these measurement areas characteristic features occur which can identify biobearing tribology. The aim of the research was the identification of surface layer of articular cartilage by means of scanning electron microscopy (SEM) and atom force microscopy (AFM) and the analysis of topography of these layers. The material used in the research of surface layer was the animal articular cartilage: hyaline cartilage and fibrocartilage.

Study on dynamic deformation synchronized measurement technology of double-layer liquid surfaces

NASA Astrophysics Data System (ADS)

Tang, Huiying; Dong, Huimin; Liu, Zhanwei

2017-11-01

Accurate measurement of the dynamic deformation of double-layer liquid surfaces plays an important role in many fields, such as fluid mechanics, biomechanics, petrochemical industry and aerospace engineering. It is difficult to measure dynamic deformation of double-layer liquid surfaces synchronously for traditional methods. In this paper, a novel and effective method for full-field static and dynamic deformation measurement of double-layer liquid surfaces has been developed, that is wavefront distortion of double-wavelength transmission light with geometric phase analysis (GPA) method. Double wavelength lattice patterns used here are produced by two techniques, one is by double wavelength laser, and the other is by liquid crystal display (LCD). The techniques combine the characteristics such as high transparency, low reflectivity and fluidity of liquid. Two color lattice patterns produced by laser and LCD were adjusted at a certain angle through the tested double-layer liquid surfaces simultaneously. On the basis of the refractive indexes difference of two transmitted lights, the double-layer liquid surfaces were decoupled with GPA method. Combined with the derived relationship between phase variation of transmission-lattice patterns and out-of plane heights of two surfaces, as well as considering the height curves of the liquid level, the double-layer liquid surfaces can be reconstructed successfully. Compared with the traditional measurement method, the developed method not only has the common advantages of the optical measurement methods, such as high-precision, full-field and non-contact, but also simple, low cost and easy to set up.

Inversion of Surface-wave Dispersion Curves due to Low-velocity-layer Models

NASA Astrophysics Data System (ADS)

Shen, C.; Xia, J.; Mi, B.

2016-12-01

A successful inversion relies on exact forward modeling methods. It is a key step to accurately calculate multi-mode dispersion curves of a given model in high-frequency surface-wave (Rayleigh wave and Love wave) methods. For normal models (shear (S)-wave velocity increasing with depth), their theoretical dispersion curves completely match the dispersion spectrum that is generated based on wave equation. For models containing a low-velocity-layer, however, phase velocities calculated by existing forward-modeling algorithms (e.g. Thomson-Haskell algorithm, Knopoff algorithm, fast vector-transfer algorithm and so on) fail to be consistent with the dispersion spectrum at a high frequency range. They will approach a value that close to the surface-wave velocity of the low-velocity-layer under the surface layer, rather than that of the surface layer when their corresponding wavelengths are short enough. This phenomenon conflicts with the characteristics of surface waves, which results in an erroneous inverted model. By comparing the theoretical dispersion curves with simulated dispersion energy, we proposed a direct and essential solution to accurately compute surface-wave phase velocities due to low-velocity-layer models. Based on the proposed forward modeling technique, we can achieve correct inversion for these types of models. Several synthetic data proved the effectiveness of our method.

A stable lithium-rich surface structure for lithium-rich layered cathode materials

PubMed Central

Kim, Sangryun; Cho, Woosuk; Zhang, Xiaobin; Oshima, Yoshifumi; Choi, Jang Wook

2016-01-01

Lithium ion batteries are encountering ever-growing demand for further increases in energy density. Li-rich layered oxides are considered a feasible solution to meet this demand because their specific capacities often surpass 200 mAh g−1 due to the additional lithium occupation in the transition metal layers. However, this lithium arrangement, in turn, triggers cation mixing with the transition metals, causing phase transitions during cycling and loss of reversible capacity. Here we report a Li-rich layered surface bearing a consistent framework with the host, in which nickel is regularly arranged between the transition metal layers. This surface structure mitigates unwanted phase transitions, improving the cycling stability. This surface modification enables a reversible capacity of 218.3 mAh g−1 at 1C (250 mA g−1) with improved cycle retention (94.1% after 100 cycles). The present surface design can be applied to various battery electrodes that suffer from structural degradations propagating from the surface. PMID:27886178

Improvement of Surface Layer Characteristics by Shot Lining

NASA Astrophysics Data System (ADS)

Harada, Yasunori

In the present study, lining of the metal with foils using shot peening was investigated to improve the surface layer characteristics. In the shot peening experiment, the foils set on the metal are pelted with hard particles traveling at a high velocity. The foils are bonded to the metal surface due to plastic deformation induced by the collision of the particles. The foils and the metal are heated to heighten the bondability because of the reduction of flow stress. Lining the metal with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a centrifugal shot peening machine wite an electrical heater was employed. The metals are commercially aluminium alloys and magnesium alloys, and the foils are commercially aluminum, titanium and nickel. The effects of shot speed and the heating temperature on the bondability were examined. Wear resistance was also evaluated by grinding. The foils were successfully bonded to the metal surface. It was found that the present method is effective in improving of surface layer characteristics.

Host-microbe interactions in distal airways: relevance to chronic airway diseases.

PubMed

Martin, Clémence; Burgel, Pierre-Régis; Lepage, Patricia; Andréjak, Claire; de Blic, Jacques; Bourdin, Arnaud; Brouard, Jacques; Chanez, Pascal; Dalphin, Jean-Charles; Deslée, Gaetan; Deschildre, Antoine; Gosset, Philippe; Touqui, Lhousseine; Dusser, Daniel

2015-03-01

This article is the summary of a workshop, which took place in November 2013, on the roles of microorganisms in chronic respiratory diseases. Until recently, it was assumed that lower airways were sterile in healthy individuals. However, it has long been acknowledged that microorganisms could be identified in distal airway secretions from patients with various respiratory diseases, including cystic fibrosis (CF) and non-CF bronchiectasis, chronic obstructive pulmonary disease, asthma and other chronic airway diseases (e.g. post-transplantation bronchiolitis obliterans). These microorganisms were sometimes considered as infectious agents that triggered host immune responses and contributed to disease onset and/or progression; alternatively, microorganisms were often considered as colonisers, which were considered unlikely to play roles in disease pathophysiology. These concepts were developed at a time when the identification of microorganisms relied on culture-based methods. Importantly, the majority of microorganisms cannot be cultured using conventional methods, and the use of novel culture-independent methods that rely on the identification of microorganism genomes has revealed that healthy distal airways display a complex flora called the airway microbiota. The present article reviews some aspects of current literature on host-microbe (mostly bacteria and viruses) interactions in healthy and diseased airways, with a special focus on distal airways. Copyright ©ERS 2015.

Effect of surface wave propagation in a four-layered oceanic crust model

NASA Astrophysics Data System (ADS)

Paul, Pasupati; Kundu, Santimoy; Mandal, Dinbandhu

2017-12-01

Dispersion of Rayleigh type surface wave propagation has been discussed in four-layered oceanic crust. It includes a sandy layer over a crystalline elastic half-space and over it there are two more layers—on the top inhomogeneous liquid layer and under it a liquid-saturated porous layer. Frequency equation is obtained in the form of determinant. The effects of the width of different layers as well as the inhomogeneity of liquid layer, sandiness of sandy layer on surface waves are depicted and shown graphically by considering all possible case of the particular model. Some special cases have been deduced, few special cases give the dispersion equation of Scholte wave and Stoneley wave, some of which have already been discussed elsewhere.

The New Perilaryngeal Airway (CobraPLA™)1 Is as Efficient as the Laryngeal Mask Airway (LMA™)2, But Provides Better Airway Sealing Pressures

PubMed Central

Akça, Ozan; Wadhwa, Anupama; Sengupta, Papiya; Durrani, Jaleel; Hanni, Keith; Wenke, Mary; Yücel, Yüksel; Lenhardt, Rainer; Doufas, Anthony G.; Sessler, Daniel I.

2006-01-01

The Laryngeal Mask Airway (LMA) is a frequently-used efficient airway device, yet it sometimes seals poorly, thus reducing the efficacy of positive-pressure ventilation. The Perilaryngeal Airway (CobraPLA) is a novel airway device with a larger pharyngeal cuff (when inflated). We tested the hypothesis that the CobraPLA was superior to LMA with regard to insertion time and airway sealing pressure and comparable to LMA in airway adequacy and recovery characteristics. After midazolam and fentanyl, 81 ASA I-II outpatients having elective surgery were randomized to receive an LMA or CobraPLA. Anesthesia was induced with propofol (2.5 mg/kg, IV), and the airway inserted. We measured 1) insertion time; 2) adequacy of the airway (no leak at 15-cm-H2O peak pressure or tidal volume of 5 ml/kg); 3) airway sealing pressure; 4) number of repositioning attempts; and 5) sealing quality (no leak at tidal volume of 8 ml/kg). At the end of surgery, gastric insufflation, postoperative sore throat, dysphonia, and dysphagia were evaluated. Data were compared with unpaired t-tests, chi-square tests, or Fisher’s Exact tests; P<0.05 was significant. Patient characteristics, insertion times, airway adequacy, number of repositioning attempts, and recovery were similar in each group. Airway sealing pressure was significantly greater with CobraPLA (23±6 cm H2O) than LMA (18±5 cm H2O, P<0.001). The CobraPLA has insertion characteristics similar to LMA, but better airway sealing capabilities. PMID:15281543

Nucleation and Early Stages of Layer-by-Layer Growth of Metal Organic Frameworks on Surfaces

PubMed Central

2015-01-01

High resolution atomic force microscopy (AFM) is used to resolve the evolution of crystallites of a metal organic framework (HKUST-1) grown on Au(111) using a liquid-phase layer-by-layer methodology. The nucleation and faceting of individual crystallites is followed by repeatedly imaging the same submicron region after each cycle of growth and we find that the growing surface is terminated by {111} facets leading to the formation of pyramidal nanostructures for [100] oriented crystallites, and triangular [111] islands with typical lateral dimensions of tens of nanometres. AFM images reveal that crystallites can grow by 5–10 layers in each cycle. The growth rate depends on crystallographic orientation and the morphology of the gold substrate, and we demonstrate that under these conditions the growth is nanocrystalline with a morphology determined by the minimum energy surface. PMID:26709359

Cystic Fibrosis Transmembrane Conductance Regulator in Sarcoplasmic Reticulum of Airway Smooth Muscle. Implications for Airway Contractility

PubMed Central

Cook, Daniel P.; Rector, Michael V.; Bouzek, Drake C.; Michalski, Andrew S.; Gansemer, Nicholas D.; Reznikov, Leah R.; Li, Xiaopeng; Stroik, Mallory R.; Ostedgaard, Lynda S.; Abou Alaiwa, Mahmoud H.; Thompson, Michael A.; Prakash, Y. S.; Krishnan, Ramaswamy; Meyerholz, David K.; Seow, Chun Y.

2016-01-01

Rationale: An asthma-like airway phenotype has been described in people with cystic fibrosis (CF). Whether these findings are directly caused by loss of CF transmembrane conductance regulator (CFTR) function or secondary to chronic airway infection and/or inflammation has been difficult to determine. Objectives: Airway contractility is primarily determined by airway smooth muscle. We tested the hypothesis that CFTR is expressed in airway smooth muscle and directly affects airway smooth muscle contractility. Methods: Newborn pigs, both wild type and with CF (before the onset of airway infection and inflammation), were used in this study. High-resolution immunofluorescence was used to identify the subcellular localization of CFTR in airway smooth muscle. Airway smooth muscle function was determined with tissue myography, intracellular calcium measurements, and regulatory myosin light chain phosphorylation status. Precision-cut lung slices were used to investigate the therapeutic potential of CFTR modulation on airway reactivity. Measurements and Main Results: We found that CFTR localizes to the sarcoplasmic reticulum compartment of airway smooth muscle and regulates airway smooth muscle tone. Loss of CFTR function led to delayed calcium reuptake following cholinergic stimulation and increased myosin light chain phosphorylation. CFTR potentiation with ivacaftor decreased airway reactivity in precision-cut lung slices following cholinergic stimulation. Conclusions: Loss of CFTR alters porcine airway smooth muscle function and may contribute to the airflow obstruction phenotype observed in human CF. Airway smooth muscle CFTR may represent a therapeutic target in CF and other diseases of airway narrowing. PMID:26488271

INDUCED SPUTUM DERIVES FROM THE CENTRAL AIRWAYS: CONFIRMATION USING A RADIOLABELED AEROSOL BOLUS DELIVERY TECHNIQUE

EPA Science Inventory

Indirect evidence suggests that induced sputum derives from the surfaces of the bronchial airways. To confirm this experimentally, we employed a radiolabeled aerosol bolus delivery technique that preferentially deposits aerosol in the central airways in humans. We hypothesized th...

Surface-Layer (S-Layer) Proteins Sap and EA1 Govern the Binding of the S-Layer-Associated Protein BslO at the Cell Septa of Bacillus anthracis

PubMed Central

Kern, Valerie J.; Kern, Justin W.; Theriot, Julie A.; Schneewind, Olaf

2012-01-01

The Gram-positive pathogen Bacillus anthracis contains 24 genes whose products harbor the structurally conserved surface-layer (S-layer) homology (SLH) domain. Proteins endowed with the SLH domain associate with the secondary cell wall polysaccharide (SCWP) following secretion. Two such proteins, Sap and EA1, have the unique ability to self-assemble into a paracrystalline layer on the surface of bacilli and form S layers. Other SLH domain proteins can also be found within the S layer and have been designated Bacillus S-layer-associated protein (BSLs). While both S-layer proteins and BSLs bind the same SCWP, their deposition on the cell surface is not random. For example, BslO is targeted to septal peptidoglycan zones, where it catalyzes the separation of daughter cells. Here we show that an insertional lesion in the sap structural gene results in elongated chains of bacilli, as observed with a bslO mutant. The chain length of the sap mutant can be reduced by the addition of purified BslO in the culture medium. This complementation in trans can be explained by an increased deposition of BslO onto the surface of sap mutant bacilli that extends beyond chain septa. Using fluorescence microscopy, we observed that the Sap S layer does not overlap the EA1 S layer and slowly yields to the EA1 S layer in a growth-phase-dependent manner. Although present all over bacilli, Sap S-layer patches are not observed at septa. Thus, we propose that the dynamic Sap/EA1 S-layer coverage of the envelope restricts the deposition of BslO to the SCWP at septal rings. PMID:22609927

Surface Ages and Resurfacing Rates of the Polar Layered Deposits on Mars

USGS Publications Warehouse

Herkenhoff, K. E.; Plaut, J.J.

2000-01-01

Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 images. No craters have been found in the north polar layered terrain, but the surface of most of the south polar layered deposits appears to have been stable for many of the orbital/axial cycles that are thought to have induced global climate changes on Mars. The inferred surface age of the south polar layered deposits (about 10 Ma) is two orders of magnitude greater than the surface age of the north polar layered deposits and residual cap (at most 100 ka). Similarly, modeled resurfacing rates are at least 20 times greater in the north than in the south. These results are consistent with the hypotheses that polar layered deposit resurfacing rates are highest in areas covered by perennial ice and that the differences in polar resurfacing rates result from the 6.4 km difference in elevation between the polar regions. Deposition on the portion of the south polar layered deposits that is not covered by the perennial ice cap may have ceased about 5 million years ago when the obliquity of Mars no longer exceeded 40??. ?? 2000 Academic Press.

Airway smooth muscle in airway reactivity and remodeling: what have we learned?

PubMed Central

2013-01-01

It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca2+]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM “activity” result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. PMID:24142517

Difficult airway response team: a novel quality improvement program for managing hospital-wide airway emergencies.

PubMed

Mark, Lynette J; Herzer, Kurt R; Cover, Renee; Pandian, Vinciya; Bhatti, Nasir I; Berkow, Lauren C; Haut, Elliott R; Hillel, Alexander T; Miller, Christina R; Feller-Kopman, David J; Schiavi, Adam J; Xie, Yanjun J; Lim, Christine; Holzmueller, Christine; Ahmad, Mueen; Thomas, Pradeep; Flint, Paul W; Mirski, Marek A

2015-07-01

Difficult airway cases can quickly become emergencies, increasing the risk of life-threatening complications or death. Emergency airway management outside the operating room is particularly challenging. We developed a quality improvement program-the Difficult Airway Response Team (DART)-to improve emergency airway management outside the operating room. DART was implemented by a team of anesthesiologists, otolaryngologists, trauma surgeons, emergency medicine physicians, and risk managers in 2005 at The Johns Hopkins Hospital in Baltimore, Maryland. The DART program had 3 core components: operations, safety, and education. The operations component focused on developing a multidisciplinary difficult airway response team, standardizing the emergency response process, and deploying difficult airway equipment carts throughout the hospital. The safety component focused on real-time monitoring of DART activations and learning from past DART events to continuously improve system-level performance. This objective entailed monitoring the paging system, reporting difficult airway events and DART activations to a Web-based registry, and using in situ simulations to identify and mitigate defects in the emergency airway management process. The educational component included development of a multispecialty difficult airway curriculum encompassing case-based lectures, simulation, and team building/communication to ensure consistency of care. Educational materials were also developed for non-DART staff and patients to inform them about the needs of patients with difficult airways and ensure continuity of care with other providers after discharge. Between July 2008 and June 2013, DART managed 360 adult difficult airway events comprising 8% of all code activations. Predisposing patient factors included body mass index >40, history of head and neck tumor, prior difficult intubation, cervical spine injury, airway edema, airway bleeding, and previous or current tracheostomy. Twenty

Difficult Airway Response Team: A Novel Quality Improvement Program for Managing Hospital-Wide Airway Emergencies

PubMed Central

Mark, Lynette J.; Herzer, Kurt R.; Cover, Renee; Pandian, Vinciya; Bhatti, Nasir I.; Berkow, Lauren C.; Haut, Elliott R.; Hillel, Alexander T.; Miller, Christina R.; Feller-Kopman, David J.; Schiavi, Adam J.; Xie, Yanjun J.; Lim, Christine; Holzmueller, Christine; Ahmad, Mueen; Thomas, Pradeep; Flint, Paul W.; Mirski, Marek A.

2015-01-01

Background Difficult airway cases can quickly become emergencies, increasing the risk of life-threatening complications or death. Emergency airway management outside the operating room is particularly challenging. Methods We developed a quality improvement program—the Difficult Airway Response Team (DART)—to improve emergency airway management outside the operating room. DART was implemented by a team of anesthesiologists, otolaryngologists, trauma surgeons, emergency medicine physicians, and risk managers in 2005 at The Johns Hopkins Hospital in Baltimore, Maryland. The DART program had three core components: operations, safety, and education. The operations component focused on developing a multidisciplinary difficult airway response team, standardizing the emergency response process, and deploying difficult airway equipment carts throughout the hospital. The safety component focused on real-time monitoring of DART activations and learning from past DART events to continuously improve system-level performance. This objective entailed monitoring the paging system, reporting difficult airway events and DART activations to a web-based registry, and using in situ simulations to identify and mitigate defects in the emergency airway management process. The educational component included development of a multispecialty difficult airway curriculum encompassing case-based lectures, simulation, and team building/communication to ensure consistency of care. Educational materials were also developed for non-DART staff and patients to inform them about the needs of patients with difficult airways and ensure continuity of care with other providers after discharge. Results Between July 2008 and June 2013, DART managed 360 adult difficult airway events comprising 8% of all code activations. Predisposing patient factors included body mass index > 40, history of head and neck tumor, prior difficult intubation, cervical spine injury, airway edema, airway bleeding, and previous

Blood sinuses in the submucosa of the large airways of the sheep.

PubMed Central

Hill, P; Goulding, D; Webber, S E; Widdicombe, J G

1989-01-01

We have studied the airway vasculature in sheep using light and transmission electron microscopy, as well as arterial and venous (retrograde) injections of anatomical corrosion compound and latex. Vascular casts were viewed by scanning electron microscopy. There is a complex network of blood sinuses of large diameter (up to 500 microns) in the submucosa of the large airways. The vessels have thin walls formed by a single layer of flattened endothelium with tight junctions and without pericytes or smooth muscle cells. Characteristically the sinuses lie between the cartilage and lamina propria of the trachea or between cartilage and smooth muscle in the bronchi. Sinuses of greater than 50 microns transverse diameter are not found in airways less than 1.0 mm across. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 7 PMID:2808119

Two-Layer Variable Infiltration Capacity Land Surface Representation for General Circulation Models

NASA Technical Reports Server (NTRS)

Xu, L.

1994-01-01

A simple two-layer variable infiltration capacity (VIC-2L) land surface model suitable for incorporation in general circulation models (GCMs) is described. The model consists of a two-layer characterization of the soil within a GCM grid cell, and uses an aerodynamic representation of latent and sensible heat fluxes at the land surface. The effects of GCM spatial subgrid variability of soil moisture and a hydrologically realistic runoff mechanism are represented in the soil layers. The model was tested using long-term hydrologic and climatalogical data for Kings Creek, Kansas to estimate and validate the hydrological parameters. Surface flux data from three First International Satellite Land Surface Climatology Project Field Experiments (FIFE) intensive field compaigns in the summer and fall of 1987 in central Kansas, and from the Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) in Brazil were used to validate the mode-simulated surface energy fluxes and surface temperature.

Airway Tree Segmentation in Serial Block-Face Cryomicrotome Images of Rat Lungs

PubMed Central

Bauer, Christian; Krueger, Melissa A.; Lamm, Wayne J.; Smith, Brian J.; Glenny, Robb W.; Beichel, Reinhard R.

2014-01-01

A highly-automated method for the segmentation of airways in serial block-face cryomicrotome images of rat lungs is presented. First, a point inside of the trachea is manually specified. Then, a set of candidate airway centerline points is automatically identified. By utilizing a novel path extraction method, a centerline path between the root of the airway tree and each point in the set of candidate centerline points is obtained. Local disturbances are robustly handled by a novel path extraction approach, which avoids the shortcut problem of standard minimum cost path algorithms. The union of all centerline paths is utilized to generate an initial airway tree structure, and a pruning algorithm is applied to automatically remove erroneous subtrees or branches. Finally, a surface segmentation method is used to obtain the airway lumen. The method was validated on five image volumes of Sprague-Dawley rats. Based on an expert-generated independent standard, an assessment of airway identification and lumen segmentation performance was conducted. The average of airway detection sensitivity was 87.4% with a 95% confidence interval (CI) of (84.9, 88.6)%. A plot of sensitivity as a function of airway radius is provided. The combined estimate of airway detection specificity was 100% with a 95% CI of (99.4, 100)%. The average number and diameter of terminal airway branches was 1179 and 159 μm, respectively. Segmentation results include airways up to 31 generations. The regression intercept and slope of airway radius measurements derived from final segmentations were estimated to be 7.22 μm and 1.005, respectively. The developed approach enables quantitative studies of physiology and lung diseases in rats, requiring detailed geometric airway models. PMID:23955692

Laryngeal mask airway for airway control during percutaneous dilatational tracheostomy.

PubMed

Pratt, T; Bromilow, J

2011-11-01

Percutaneous dilatational tracheostomy is a common bedside procedure in critical care for patients requiring prolonged mechanical ventilation. The traditional technique requires withdrawal of the endotracheal tube to a proximal position to facilitate tracheostomy insertion, but this carries the risk of inadvertent extubation and does not prevent cuff rupture. Use of a supraglottic airway such as the laryngeal mask airway may avoid these risks and could provide a safe alternative to the endotracheal tube. We present an appraisal of the literature to date. We found reasonable evidence to show improved ventilation and bronchoscopic visualisation with the laryngeal mask airway, but this has not been translated into improved outcome. There is currently insufficient evidence to draw conclusions about the safety of the laryngeal mask airway during percutaneous dilatational tracheostomy.

Diurnal ocean surface layer model validation

NASA Technical Reports Server (NTRS)

Hawkins, Jeffrey D.; May, Douglas A.; Abell, Fred, Jr.

1990-01-01

The diurnal ocean surface layer (DOSL) model at the Fleet Numerical Oceanography Center forecasts the 24-hour change in a global sea surface temperatures (SST). Validating the DOSL model is a difficult task due to the huge areas involved and the lack of in situ measurements. Therefore, this report details the use of satellite infrared multichannel SST imagery to provide day and night SSTs that can be directly compared to DOSL products. This water-vapor-corrected imagery has the advantages of high thermal sensitivity (0.12 C), large synoptic coverage (nearly 3000 km across), and high spatial resolution that enables diurnal heating events to be readily located and mapped. Several case studies in the subtropical North Atlantic readily show that DOSL results during extreme heating periods agree very well with satellite-imagery-derived values in terms of the pattern of diurnal warming. The low wind and cloud-free conditions necessary for these events to occur lend themselves well to observation via infrared imagery. Thus, the normally cloud-limited aspects of satellite imagery do not come into play for these particular environmental conditions. The fact that the DOSL model does well in extreme events is beneficial from the standpoint that these cases can be associated with the destruction of the surface acoustic duct. This so-called afternoon effect happens as the afternoon warming of the mixed layer disrupts the sound channel and the propagation of acoustic energy.

Inflammation Promotes Airway Epithelial ATP Release via Calcium-Dependent Vesicular Pathways

PubMed Central

Okada, Seiko F.; Ribeiro, Carla M. P.; Sesma, Juliana I.; Seminario-Vidal, Lucia; Abdullah, Lubna H.; van Heusden, Catharina; Lazarowski, Eduardo R.

2013-01-01

ATP in airway surface liquid (ASL) controls mucociliary clearance functions via the activation of airway epithelial purinergic receptors. However, abnormally elevated ATP levels have been reported in inflamed airways, suggesting that excessive ATP in ASL contributes to airway inflammation. Despite these observations, little is known about the mechanisms of ATP accumulation in the ASL covering inflamed airways. In this study, links between cystic fibrosis (CF)–associated airway inflammation and airway epithelial ATP release were investigated. Primary human bronchial epithelial (HBE) cells isolated from CF lungs exhibited enhanced IL-8 secretion after 6 to 11 days, but not 28 to 35 days, in culture, compared with normal HBE cells. Hypotonic cell swelling–promoted ATP release was increased in 6- to 11-day-old CF HBE cells compared with non-CF HBE cells, but returned to normal values after 28 to 35 days in culture. The exposure of non-CF HBE cells to airway secretions isolated from CF lungs, namely, sterile supernatants of mucopurulent material (SMM), also caused enhanced IL-8 secretion and increased ATP release. The SMM-induced increase in ATP release was sensitive to Ca2+ chelation and vesicle trafficking/exocytosis inhibitors, but not to pannexin inhibition. Transcript levels of the vesicular nucleotide transporter, but not pannexin 1, were up-regulated after SMM exposure. SMM-treated cultures displayed increased basal mucin secretion, but mucin secretion was not enhanced in response to hypotonic challenge after the exposure of cells to either vehicle or SMM. We propose that CF airway inflammation up-regulates the capacity of airway epithelia to release ATP via Ca2+-dependent vesicular mechanisms not associated with mucin granule secretion. PMID:23763446

Surface influence upon vertical profiles in the nocturnal boundary layer

NASA Astrophysics Data System (ADS)

Garratt, J. R.

1983-05-01

Near-surface wind profiles in the nocturnal boundary layer, depth h, above relatively flat, tree-covered terrain are described in the context of the analysis of Garratt (1980) for the unstable atmospheric boundary layer. The observations at two sites imply a surface-based transition layer, of depth z *, within which the observed non-dimensional profiles Φ M 0 are a modified form of the inertial sub-layer relation Φ _M ( {{z L}} = ( {{{1 + 5_Z } L}} ) according to Φ _M^{{0}} ˜eq ( {{{1 + 5z} L}} )exp [ { - 0.7( {{{1 - z} z}_ * } )] , where z is height above the zero-plane displacement and L is the Monin-Obukhov length. At both sites the depth z * is significantly smaller than the appropriate neutral value ( z * N ) found from the previous analysis, as might be expected in the presence of a buoyant sink for turbulent kinetic energy.

Use of a Novel Airway Kit and Simulation in Resident Training on Emergent Pediatric Airways.

PubMed

Melzer, Jonathan M; Hamersley, Erin R S; Gallagher, Thomas Q

2017-06-01

Objective Development of a novel pediatric airway kit and implementation with simulation to improve resident response to emergencies with the goal of improving patient safety. Methods Prospective study with 9 otolaryngology residents (postgraduate years 1-5) from our tertiary care institution. Nine simulated pediatric emergency airway drills were carried out with the existing system and a novel portable airway kit. Response times and time to successful airway control were noted with both the extant airway system and the new handheld kit. Results were analyzed to ensure parametric data and compared with t tests. A Bonferroni adjustment indicated that an alpha of 0.025 was needed for significance. Results Use of the airway kit significantly reduced the mean time of resident arrival by 47% ( P = .013) and mean time of successful intubation by 50% ( P = .007). Survey data indicated 100% improved resident comfort with emergent airway scenarios with use of the kit. Discussion Times to response and meaningful intervention were significantly reduced with implementation of the handheld airway kit. Use of simulation training to implement the new kit improved residents' comfort and airway skills. This study describes an affordable novel mobile airway kit and demonstrates its ability to improve response times. Implications for Practice The low cost of this airway kit makes it a tenable option even for smaller hospitals. Simulation provides a safe and effective way to familiarize oneself with novel equipment, and, when possible, realistic emergent airway simulations should be used to improve provider performance.

The microstructure of the surface layer of magnesium laser alloyed with aluminum and silicon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dziadoń, Andrzej

2016-08-15

The surface layer under analysis was formed as a result of diffusion bonding of a thin AlSi20 plate to a magnesium substrate followed by laser melting. Depending on the process parameters, the laser beam melted the AlSi20 plate only or the AlSi20 plate and a layer of the magnesium surface adjacent to it. Two types of microstructure of the remelted layer were thus analyzed. If the melting zone was limited to the AlSi20 plate, the microstructure of the surface layer was typical of a rapidly solidified hypereutectic Al–Si alloy. Since, however, the liquid AlSi20 reacted with the magnesium substrate, themore » following intermetallic phases formed: Al{sub 3}Mg{sub 2}, Mg{sub 17}Al{sub 12} and Mg{sub 2}Si. The microstructure of the modified surface layer of magnesium was examined using optical, scanning electron and transmission electron microscopy. The analysis of the surface properties of the laser modified magnesium revealed that the thin layer has a microstructure of a rapidly solidified Al–Si alloy offering good protection against corrosion. By contrast, the surface layer containing particles of intermetallic phases was more resistant to abrasion but had lower corrosion resistance than the silumin type layer. - Highlights: •A CO{sub 2} laser was used for surface alloying of Mg with AlSi20. •Before alloying, an AlSi20 plate was diffusion bonded with the Mg substrate. •The process parameters affected the alloyed layer microstructure and properties. •With melting limited to AlSi20, the layer had a structure of rapidly solidified AlSi20. •Mg–Al and Mg–Si phases were present when both the substrate and the plate were melted.« less

Efficacy of Surgical Airway Plasty for Benign Airway Stenosis.

PubMed

Tsukioka, Takuma; Takahama, Makoto; Nakajima, Ryu; Kimura, Michitaka; Inoue, Hidetoshi; Yamamoto, Ryoji

2016-01-01

Long-term patency is required during treatment for benign airway stenosis. This study investigated the effectiveness of surgical airway plasty for benign airway stenosis. Clinical courses of 20 patients, who were treated with surgical plasty for their benign airway stenosis, were retrospectively investigated. Causes of stenosis were tracheobronchial tuberculosis in 12 patients, post-intubation stenosis in five patients, malacia in two patients, and others in one patient. 28 interventional pulmonology procedures and 20 surgical plasty were performed. Five patients with post-intubation stenosis and four patients with tuberculous stenosis were treated with tracheoplasty. Eight patients with tuberculous stenosis were treated with bronchoplasty, and two patients with malacia were treated with stabilization of the membranous portion. Anastomotic stenosis was observed in four patients, and one to four additional treatments were required. Performance status, Hugh-Jones classification, and ventilatory functions were improved after surgical plasty. Outcomes were fair in patients with tuberculous stenosis and malacia. However, efficacy of surgical plasty for post-intubation stenosis was not observed. Surgical airway plasty may be an acceptable treatment for tuberculous stenosis. Patients with malacia recover well after surgical plasty. There may be untreated patients with malacia who have the potential to benefit from surgical plasty.

Efficacy of Surgical Airway Plasty for Benign Airway Stenosis

PubMed Central

Takahama, Makoto; Nakajima, Ryu; Kimura, Michitaka; Inoue, Hidetoshi; Yamamoto, Ryoji

2015-01-01

Background: Long-term patency is required during treatment for benign airway stenosis. This study investigated the effectiveness of surgical airway plasty for benign airway stenosis. Methods: Clinical courses of 20 patients, who were treated with surgical plasty for their benign airway stenosis, were retrospectively investigated. Results: Causes of stenosis were tracheobronchial tuberculosis in 12 patients, post-intubation stenosis in five patients, malacia in two patients, and others in one patient. 28 interventional pulmonology procedures and 20 surgical plasty were performed. Five patients with post-intubation stenosis and four patients with tuberculous stenosis were treated with tracheoplasty. Eight patients with tuberculous stenosis were treated with bronchoplasty, and two patients with malacia were treated with stabilization of the membranous portion. Anastomotic stenosis was observed in four patients, and one to four additional treatments were required. Performance status, Hugh–Jones classification, and ventilatory functions were improved after surgical plasty. Outcomes were fair in patients with tuberculous stenosis and malacia. However, efficacy of surgical plasty for post-intubation stenosis was not observed. Conclusion: Surgical airway plasty may be an acceptable treatment for tuberculous stenosis. Patients with malacia recover well after surgical plasty. There may be untreated patients with malacia who have the potential to benefit from surgical plasty. PMID:26567879

Manufacture of silicon-based devices having disordered sulfur-doped surface layers

DOEpatents

Carey, III; Edward, James [Newton, MA; Mazur, Eric [Concord, MA

2008-04-08

The present invention provides methods of fabricating a radiation-absorbing semiconductor wafer by irradiating at least one surface location of a silicon substrate, e.g., an n-doped crystalline silicon, by a plurality of temporally short laser pulses, e.g., femtosecond pulses, while exposing that location to a substance, e.g., SF.sub.6, having an electron-donating constituent so as to generate a substantially disordered surface layer (i.e., a microstructured layer) that incorporates a concentration of that electron-donating constituent, e.g., sulfur. The substrate is also annealed at an elevated temperature and for a duration selected to enhance the charge carrier density in the surface layer. For example, the substrate can be annealed at a temperature in a range of about 700 K to about 900 K.

An automatic generation of non-uniform mesh for CFD analyses of image-based multiscale human airway models

NASA Astrophysics Data System (ADS)

Miyawaki, Shinjiro; Tawhai, Merryn H.; Hoffman, Eric A.; Lin, Ching-Long

2014-11-01

The authors have developed a method to automatically generate non-uniform CFD mesh for image-based human airway models. The sizes of generated tetrahedral elements vary in both radial and longitudinal directions to account for boundary layer and multiscale nature of pulmonary airflow. The proposed method takes advantage of our previously developed centerline-based geometry reconstruction method. In order to generate the mesh branch by branch in parallel, we used the open-source programs Gmsh and TetGen for surface and volume meshes, respectively. Both programs can specify element sizes by means of background mesh. The size of an arbitrary element in the domain is a function of wall distance, element size on the wall, and element size at the center of airway lumen. The element sizes on the wall are computed based on local flow rate and airway diameter. The total number of elements in the non-uniform mesh (10 M) was about half of that in the uniform mesh, although the computational time for the non-uniform mesh was about twice longer (170 min). The proposed method generates CFD meshes with fine elements near the wall and smooth variation of element size in longitudinal direction, which are required, e.g., for simulations with high flow rate. NIH Grants R01-HL094315, U01-HL114494, and S10-RR022421. Computer time provided by XSEDE.

Surfactant-associated bacteria in the near-surface layer of the ocean.

PubMed

Kurata, Naoko; Vella, Kate; Hamilton, Bryan; Shivji, Mahmood; Soloviev, Alexander; Matt, Silvia; Tartar, Aurélien; Perrie, William

2016-01-12

Certain marine bacteria found in the near-surface layer of the ocean are expected to play important roles in the production and decay of surface active materials; however, the details of these processes are still unclear. Here we provide evidence supporting connection between the presence of surfactant-associated bacteria in the near-surface layer of the ocean, slicks on the sea surface, and a distinctive feature in the synthetic aperture radar (SAR) imagery of the sea surface. From DNA analyses of the in situ samples using pyrosequencing technology, we found the highest abundance of surfactant-associated bacterial taxa in the near-surface layer below the slick. Our study suggests that production of surfactants by marine bacteria takes place in the organic-rich areas of the water column. Produced surfactants can then be transported to the sea surface and form slicks when certain physical conditions are met. This finding has potential applications in monitoring organic materials in the water column using remote sensing techniques. Identifying a connection between marine bacteria and production of natural surfactants may provide a better understanding of the global picture of biophysical processes at the boundary between the ocean and atmosphere, air-sea exchange of greenhouse gases, and production of climate-active marine aerosols.

Surfactant-associated bacteria in the near-surface layer of the ocean

PubMed Central

Kurata, Naoko; Vella, Kate; Hamilton, Bryan; Shivji, Mahmood; Soloviev, Alexander; Matt, Silvia; Tartar, Aurélien; Perrie, William

2016-01-01

Certain marine bacteria found in the near-surface layer of the ocean are expected to play important roles in the production and decay of surface active materials; however, the details of these processes are still unclear. Here we provide evidence supporting connection between the presence of surfactant-associated bacteria in the near-surface layer of the ocean, slicks on the sea surface, and a distinctive feature in the synthetic aperture radar (SAR) imagery of the sea surface. From DNA analyses of the in situ samples using pyrosequencing technology, we found the highest abundance of surfactant-associated bacterial taxa in the near-surface layer below the slick. Our study suggests that production of surfactants by marine bacteria takes place in the organic-rich areas of the water column. Produced surfactants can then be transported to the sea surface and form slicks when certain physical conditions are met. This finding has potential applications in monitoring organic materials in the water column using remote sensing techniques. Identifying a connection between marine bacteria and production of natural surfactants may provide a better understanding of the global picture of biophysical processes at the boundary between the ocean and atmosphere, air-sea exchange of greenhouse gases, and production of climate-active marine aerosols. PMID:26753514

Using Ground Measurements to Examine the Surface Layer Parameterization Scheme in NCEP GFS

NASA Astrophysics Data System (ADS)

Zheng, W.; Ek, M. B.; Mitchell, K.

2017-12-01

Understanding the behavior and the limitation of the surface layer parameneterization scheme is important for parameterization of surface-atmosphere exchange processes in atmospheric models, accurate prediction of near-surface temperature and identifying the role of different physical processes in contributing to errors. In this study, we examine the surface layer paramerization scheme in the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) using the ground flux measurements including the FLUXNET data. The model simulated surface fluxes, surface temperature and vertical profiles of temperature and wind speed are compared against the observations. The limits of applicability of the Monin-Obukhov similarity theory (MOST), which describes the vertical behavior of nondimensionalized mean flow and turbulence properties within the surface layer, are quantified in daytime and nighttime using the data. Results from unstable regimes and stable regimes are discussed.

Airflow, transport and regional deposition of aerosol particles during chronic bronchitis of human central airways.

PubMed

Farkhadnia, Fouad; Gorji, Tahereh B; Gorji-Bandpy, Mofid

2016-03-01

In the present study, the effects of airway blockage in chronic bronchitis disease on the flow patterns and transport/deposition of micro-particles in a human symmetric triple bifurcation lung airway model, i.e., Weibel's generations G3-G6 was investigated. A computational fluid and particle dynamics model was implemented, validated and applied in order to evaluate the airflow and particle transport/deposition in central airways. Three breathing patterns, i.e., resting, light activity and moderate exercise, were considered. Using Lagrangian approach for particle tracking and random particle injection, an unsteady particle tracking method was performed to simulate the transport and deposition of micron-sized aerosol particles in human central airways. Assuming laminar, quasi-steady, three-dimensional air flow and spherical non-interacting particles in sequentially bifurcating rigid airways, airflow patterns and particle transport/deposition in healthy and chronic bronchitis (CB) affected airways were evaluated and compared. Comparison of deposition efficiency (DE) of aerosols in healthy and occluded airways showed that at the same flow rates DE values are typically larger in occluded airways. While in healthy airways, particles deposit mainly around the carinal ridges and flow dividers--due to direct inertial impaction, in CB affected airways they deposit mainly on the tubular surfaces of blocked airways because of gravitational sedimentation.

Observations of near-surface fresh layers during SPURS-2

NASA Astrophysics Data System (ADS)

Drushka, Kyla; E Asher, William; Thompson, Elizabeth; Jessup, Andrew T.; Clark, Dan

2017-04-01

One of the primary objectives of the ongoing SPURS-2 program is to understand the fate of rainfall deposited on the sea surface. Rain produces stable near-surface fresh layers that persist for O(1-10) hours. The depth, strength, and lifetime of surface fresh layers are known to be related to the local rain and wind conditions, but available observational data are too sparse to allow definitive quantification of cause-and-effect relationships. In this paper, the formation and evolution of rain-formed fresh layers are examined using observations of near-surface salinity made during the 2016 SPURS-2 field experiment, which took place in the Intertropical Convergence Zone of the eastern tropical Pacific Ocean in August-September 2016. During 2016 SPURS-2, over 30 rain events were captured with the Surface Salinity Profiler (SSP), a towed platform that measures salinity and temperature at five discrete depths in the upper meter of the ocean. Differences in salinity measured by the SSP at depths of 0.02 m and at 1 m are correlated with local meteorological conditions. The field results show that the salinity difference increases linearly with rain rate, a result that is consistent with calculations done with a one-dimensional ocean turbulence model. The field data also demonstrate that there is an inverse correlation between wind speed and the vertical salinity difference, which is also consistent with numerical models. The implications of these results are discussed in the context of satellite salinity observations and the representation of rainfall events in climate models.

Surface Morphology Transformation Under High-Temperature Annealing of Ge Layers Deposited on Si(100).

PubMed

Shklyaev, A A; Latyshev, A V

2016-12-01

We study the surface morphology and chemical composition of SiGe layers after their formation under high-temperature annealing at 800-1100 °C of 30-150 nm Ge layers deposited on Si(100) at 400-500 °C. It is found that the annealing leads to the appearance of the SiGe layers of two types, i.e., porous and continuous. The continuous layers have a smoothened surface morphology and a high concentration of threading dislocations. The porous and continuous layers can coexist. Their formation conditions and the ratio between their areas on the surface depend on the thickness of deposited Ge layers, as well as on the temperature and the annealing time. The data obtained suggest that the porous SiGe layers are formed due to melting of the strained Ge layers and their solidification in the conditions of SiGe dewetting on Si. The porous and dislocation-rich SiGe layers may have properties interesting for applications.

Role of humidity in reducing the friction of graphene layers on textured surfaces

NASA Astrophysics Data System (ADS)

Li, Zheng-yang; Yang, Wen-jing; Wu, Yan-ping; Wu, Song-bo; Cai, Zhen-bing

2017-05-01

A multiple-layer graphene was prepared on steel surface to reduce friction and wear. A graphene-containing ethanol solution was dripped on the steel surface, and several layers of graphene flakes were deposited on the surface after ethanol evaporated. Tribological performance of graphene-contained surface (GCS) was induced by reciprocating ball against plate contact in different RH (0% (dry nitrogen), 30%, 60%, and 90%). Morphology and wear scar were analyzed by OM, 2D profile, SEM, Raman spectroscopy, and XPS. Results show that GCS can substantially reduce the wear and coefficient of friction (COF) in 60% relative humidity (RH). Low COF occurs due to graphene layer providing a small shear stress on the friction interface. Meanwhile, conditions of high RH and textured surface could make the low COF persist for a longer time. High moisture content can stabilize and protect the graphene C-network from damage due to water dissociative chemisorption with carbon dangling bonds, and the textured surface was attributed to release graphene layer stored in the dimple.

On the Effects of Surface Roughness on Boundary Layer Transition

NASA Technical Reports Server (NTRS)

Choudhari, Meelan M.; Li, Fei; Chang, Chau-Lyan; Edwards, Jack

2009-01-01

Surface roughness can influence laminar-turbulent transition in many different ways. This paper outlines selected analyses performed at the NASA Langley Research Center, ranging in speed from subsonic to hypersonic Mach numbers and highlighting the beneficial as well as adverse roles of the surface roughness in technological applications. The first theme pertains to boundary-layer tripping on the forebody of a hypersonic airbreathing configuration via a spanwise periodic array of trip elements, with the goal of understanding the physical mechanisms underlying roughness-induced transition in a high-speed boundary layer. The effect of an isolated, finite amplitude roughness element on a supersonic boundary layer is considered next. The other set of flow configurations examined herein corresponds to roughness based laminar flow control in subsonic and supersonic swept wing boundary layers. A common theme to all of the above configurations is the need to apply higher fidelity, physics based techniques to develop reliable predictions of roughness effects on laminar-turbulent transition.

Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

NASA Astrophysics Data System (ADS)

Brown, Matthew A.; Abbas, Zareen; Kleibert, Armin; Green, Richard G.; Goel, Alok; May, Sylvio; Squires, Todd M.

2016-01-01

The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li+ , Na+ , K+ , and Cs+ ) in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

Heat transfer and phase transitions of water in multi-layer cryolithozone-surface systems

NASA Astrophysics Data System (ADS)

Khabibullin, I. L.; Nigametyanova, G. A.; Nazmutdinov, F. F.

2018-01-01

A mathematical model for calculating the distribution of temperature and the dynamics of the phase transfor-mations of water in multilayer systems on permafrost-zone surface is proposed. The model allows one to perform calculations in the annual cycle, taking into account the distribution of temperature on the surface in warm and cold seasons. A system involving four layers, a snow or land cover, a top layer of soil, a layer of thermal-insulation materi-al, and a mineral soil, is analyzed. The calculations by the model allow one to choose the optimal thickness and com-position of the layers which would ensure the stability of structures built on the permafrost-zone surface.

Turbulent dusty boundary layer in an ANFO surface-burst explosion

NASA Astrophysics Data System (ADS)

Kuhl, A. L.; Ferguson, R. E.; Chien, K. Y.; Collins, J. P.

1992-01-01

This paper describes the results of numerical simulations of the dusty, turbulent boundary layer created by a surface burst explosion. The blast wave was generated by the detonation of a 600-T hemisphere of ANFO, similar to those used in large-scale field tests. The surface was assumed to be ideally noncratering but contained an initial loose layer of dust. The dust-air mixture in this fluidized bed was modeled as a dense gas (i.e., an equilibrium model, valid for very small-diameter dust particles). The evolution of the flow was calculated by a high-order Godunov code that solves the nonsteady conservation laws. Shock interactions with dense layer generated vorticity near the wall, a result that is similar to viscous, no-slip effects found in clean flows. The resulting wall shear layer was unstable, and rolled up into large-scale rotational structures. These structures entrained dense material from the wall layer and created a chaotically striated flow. The boundary layer grew due to merging of the large-scale structures and due to local entrainment of the dense material from the fluidized bed. The chaotic flow was averaged along similarity lines (i.e., lines of constant values of x = r/Rs and y = z/Rs where R(sub s) = ct(exp alpha)) to establish the mean-flow profiles and the r.m.s. fluctuating-flow profiles of the boundary layer.

Hierarchical Composite Membranes with Robust Omniphobic Surface Using Layer-By-Layer Assembly Technique.

PubMed

Woo, Yun Chul; Kim, Youngjin; Yao, Minwei; Tijing, Leonard D; Choi, June-Seok; Lee, Sangho; Kim, Seung-Hyun; Shon, Ho Kyong

2018-02-20

In this study, composite membranes were fabricated via layer-by-layer (LBL) assembly of negatively charged silica aerogel (SiA) and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FTCS) on a polyvinylidene fluoride phase inversion membrane and interconnecting them with positively charged poly(diallyldimethylammonium chloride) (PDDA) via electrostatic interaction. The results showed that the PDDA-SiA-FTCS coated membrane had significantly enhanced the membrane structure and properties. New trifluoromethyl and tetrafluoroethylene bonds appeared at the surface of the coated membrane, which led to lower surface free energy of the composite membrane. Additionally, the LBL membrane showed increased surface roughness. The improved structure and property gave the LBL membrane an omniphobic property, as indicated by its good wetting resistance. The membrane performed a stable air gap membrane distillation (AGMD) flux of 11.22 L/m 2 h with very high salt rejection using reverse osmosis brine from coal seam gas produced water as feed with the addition of up to 0.5 mM SDS solution. This performance was much better compared to those of the neat membrane. The present study suggests that the enhanced membrane properties with good omniphobicity via LBL assembly make the porous membranes suitable for long-term AGMD operation with stable permeation flux when treating challenging saline wastewater containing low surface tension organic contaminants.

Cockroach protease allergen induces allergic airway inflammation via epithelial cell activation

PubMed Central

Kale, Sagar L.; Agrawal, Komal; Gaur, Shailendra Nath; Arora, Naveen

2017-01-01

Protease allergens are known to enhance allergic inflammation but their exact role in initiation of allergic reactions at mucosal surfaces still remains elusive. This study was aimed at deciphering the role of serine protease activity of Per a 10, a major cockroach allergen in initiation of allergic inflammation at mucosal surfaces. We demonstrate that Per a 10 increases epithelial permeability by disruption of tight junction proteins, ZO-1 and occludin, and enhances the migration of Monocyte derived dendritic cell precursors towards epithelial layer as exhibited by trans-well studies. Per a 10 exposure also leads to secretion of IL-33, TSLP and intracellular Ca2+ dependent increase in ATP levels. Further, in vivo experiments revealed that Per a 10 administration in mice elevated allergic inflammatory parameters along with high levels of IL-33, TSLP, IL-1α and uric acid in the mice lungs. We next demonstrated that Per a 10 cleaves CD23 (low affinity IgE receptor) from the surface of PBMCs and purified B cells and CD25 (IL-2 receptor) from the surface of PBMCs and purified T cells in an activity dependent manner, which might favour Th2 responses. In conclusion, protease activity of Per a 10 plays a significant role in initiation of allergic airway inflammation at the mucosal surfaces. PMID:28198394

Resistivity scaling due to electron surface scattering in thin metal layers

NASA Astrophysics Data System (ADS)

Zhou, Tianji; Gall, Daniel

2018-04-01

The effect of electron surface scattering on the thickness-dependent electrical resistivity ρ of thin metal layers is investigated using nonequilibrium Green's function density functional transport simulations. Cu(001) thin films with thickness d =1 -2 nm are used as a model system, employing a random one-monolayer-high surface roughness and frozen phonons to cause surface and bulk scattering, respectively. The zero-temperature resistivity increases from 9.7 ±1.0 μ Ω cm at d =1.99 nm to 18.7 ±2.6 μ Ω cm at d =0.9 0 nm, contradicting the asymptotic T =0 prediction from the classical Fuchs-Sondheimer model. At T =9 00 K, ρ =5.8 ±0.1 μ Ω cm for bulk Cu and ρ =13.4 ±1.1 and 22.5 ±2.4 μ Ω cm for layers with d =1.99 and 0.90 nm, respectively, indicating an approximately additive phonon contribution which, however, is smaller than for bulk Cu or atomically smooth layers. The overall data indicate that the resistivity contribution from surface scattering is temperature-independent and proportional to 1 /d , suggesting that it can be described using a surface-scattering mean-free path λs for 2D transport which is channel-independent and proportional to d . Data fitting indicates λs=4 ×d for the particular simulated Cu(001) surfaces with a one-monolayer-high surface roughness. The 1 /d dependence deviates considerably from previous 1 /d2 predictions from quantum models, indicating that the small-roughness approximation in these models is not applicable to very thin (<2 nm) layers, where the surface roughness is a considerable fraction of d .

Airway management in neuroanesthesiology.

PubMed

Aziz, Michael

2012-06-01

Airway management for neuroanesthesiology brings together some key principles that are shared throughout neuroanesthesiology. This article appropriately targets the cervical spine with associated injury and the challenges surrounding airway management. The primary focus of this article is on the unique airway management obstacles encountered with cervical spine injury or cervical spine surgery, and unique considerations regarding functional neurosurgery are addressed. Furthermore, topics related to difficult airway management for those with rheumatoid arthritis or pituitary surgery are reviewed. Copyright © 2012 Elsevier Inc. All rights reserved.

[The research on the airway hyperresponsiveness and IOS airway resistance index of industrial area resident].

PubMed

Xu, Jin; Wang, Zhen; Sun, Hongcun

2015-09-01

To study airway reactivity and impulse oscillation (IOS)-measured airway resistance indicators of residents of Zhenhai industrial area in Ningbo city. In the form of follow-up, both. airway reactivity and respiratory functions of populations in Zhenhai industrial zone (n = 215) and urban (n = 203) were measured, comparing difference degree between different regions. Ninty-five of 215 cases in industrial area were identified as suspected airway hyperresponsiveness, but only 43 of 203 cases were in urban areas. Forty-seven of 95 cases (49.5%) in industrial zone were positive, while only 14 cases (32.6%) in urban. The proportions of people in the two regions on different types of airway hyperresponsiveness were significantly different (P < 0.01). All airway resistance indexes of urban populations were significantly lower than that of industrial zone (P < 0.05). The prevalence of airway hyperresponsiveness and IOS airway resistance aspects of industrial area residents was higher than that of urban residents. Monitoring and evaluating the airway diseases, inflammatory lesions and respiratory function in the region were good for understanding the severe pollution in the local area in certain significance.

Surface acoustic waves in one-dimensional piezoelectric-metallic phononic crystal: Effect of a cap layer.

PubMed

Alami, M; El Boudouti, E H; Djafari-Rouhani, B; El Hassouani, Y; Talbi, A

2018-06-18

We study the propagation of transverse acoustic waves associated with the surface of a semi-infinite superlattice (SL) composed of piezoelectric-metallic layers and capped with a piezoelectric layer. We present closed-form expressions for localized surface waves, the so-called Bleustein-Gulyaev (BG) waves depending on whether the cap layer is open-circuited or short-circuited. These expressions are obtained by means of the Green's function method which enables to deduce also the densities of states. These theoretical results are illustrated by a few numerical applications to SLs made of piezoelectric layers of hexagonal symmetry belonging to the 6 mm class such as PZT4 and ZnO in contact with metallic layers such as Fe, Al, Au, Cu and boron-doped-diamond. We demonstrate a rule about the existence of surface modes when considering two complementary semi-infinite SLs obtained by the cleavage of an infinite SL along a plane parallel to the piezoelectric layers. Indeed, when the surface layers are open-circuited, one obtains one surface mode per gap, this mode is associated with one of the two complementary SLs. However, when the surface layers are short-circuited, this rule is not fulfilled and one can obtain zero, one or two modes inside each gap of the two complementary SLs depending on the position of the plane where the cleavage is produced. We show that in addition to the BG surface waves localized at the surface of the cap layer, there may exist true guided waves and pseudo-guided waves (i.e. leaky waves) induced by the cap layer either inside the gaps or inside the bands of the SL respectively. Also, we highlight the possibility of existence of interface modes between the SL and a cap layer as well as an interaction between these modes and the BG surface mode when both modes fall in the same band gaps of the SL. The strength of the interaction depends on the width of the cap layer. Finally, we show that the electromechanical coupling coefficient (ECC) is very

Calcium-activated chloride channel TMEM16A modulates mucin secretion and airway smooth muscle contraction.

PubMed

Huang, Fen; Zhang, Hongkang; Wu, Meng; Yang, Huanghe; Kudo, Makoto; Peters, Christian J; Woodruff, Prescott G; Solberg, Owen D; Donne, Matthew L; Huang, Xiaozhu; Sheppard, Dean; Fahy, John V; Wolters, Paul J; Hogan, Brigid L M; Finkbeiner, Walter E; Li, Min; Jan, Yuh-Nung; Jan, Lily Yeh; Rock, Jason R

2012-10-02

Mucous cell hyperplasia and airway smooth muscle (ASM) hyperresponsiveness are hallmark features of inflammatory airway diseases, including asthma. Here, we show that the recently identified calcium-activated chloride channel (CaCC) TMEM16A is expressed in the adult airway surface epithelium and ASM. The epithelial expression is increased in asthmatics, particularly in secretory cells. Based on this and the proposed functions of CaCC, we hypothesized that TMEM16A inhibitors would negatively regulate both epithelial mucin secretion and ASM contraction. We used a high-throughput screen to identify small-molecule blockers of TMEM16A-CaCC channels. We show that inhibition of TMEM16A-CaCC significantly impairs mucus secretion in primary human airway surface epithelial cells. Furthermore, inhibition of TMEM16A-CaCC significantly reduces mouse and human ASM contraction in response to cholinergic agonists. TMEM16A-CaCC blockers, including those identified here, may positively impact multiple causes of asthma symptoms.

Emergency airway puncture

MedlinePlus

... support for only a very short period of time. Alternative Names Needle cricothyrotomy Images Emergency airway puncture Cricoid cartilage Emergency airway puncture - series References Hebert RB, Bose S, Mace SE. Cricothyrotomy and ...

Recycling inflow method for simulations of spatially evolving turbulent boundary layers over rough surfaces

NASA Astrophysics Data System (ADS)

Yang, Xiang I. A.; Meneveau, Charles

2016-01-01

The technique by Lund et al. to generate turbulent inflow for simulations of developing boundary layers over smooth flat plates is extended to the case of surfaces with roughness elements. In the Lund et al. method, turbulent velocities on a sampling plane are rescaled and recycled back to the inlet as inflow boundary condition. To rescale mean and fluctuating velocities, appropriate length scales need be identified and for smooth surfaces, the viscous scale lν = ν/uτ (where ν is the kinematic viscosity and uτ is the friction velocity) is employed for the inner layer. Different from smooth surfaces, in rough wall boundary layers the length scale of the inner layer, i.e. the roughness sub-layer scale ld, must be determined by the geometric details of the surface roughness elements and the flow around them. In the proposed approach, it is determined by diagnosing dispersive stresses that quantify the spatial inhomogeneity caused by the roughness elements in the flow. The scale ld is used for rescaling in the inner layer, and the boundary layer thickness δ is used in the outer region. Both parts are then combined for recycling using a blending function. Unlike the blending function proposed by Lund et al. which transitions from the inner layer to the outer layer at approximately 0.2δ, here the location of blending is shifted upwards to enable simulations of very rough surfaces in which the roughness length may exceed the height of 0.2δ assumed in the traditional method. The extended rescaling-recycling method is tested in large eddy simulation of flow over surfaces with various types of roughness element shapes.

Effects of Surface Roughness and Mechanical Properties of Cover-Layer on Near-Field Optical Recording

NASA Astrophysics Data System (ADS)

Kim, Jin-Hong; Lee, Jun-Seok; Lim, Jungshik; Seo, Jung-Kyo

2009-03-01

Narrow gap distance in cover-layer incident near-field recording (NFR) configuration causes a collision problem in the interface between a solid immersion lens and a disk surface. A polymer cover-layer with smooth surface results in a stable gap servo while a nanocomposite cover-layer with high refractive index shows a collision problem during the gap servo test. Even though a dielectric cover-layer, in which the surface is rougher than the polymer, supplements the mechanical properties, an unclear eye pattern due to an unstable gap servo can be obtained after a chemical mechanical polishing. Not only smooth surface but also good mechanical properties of cover-layer are required for the stable gap servo in the NFR.

The dynamic deformation of a layered viscoelastic medium under surface excitation

NASA Astrophysics Data System (ADS)

Aglyamov, Salavat R.; Wang, Shang; Karpiouk, Andrei B.; Li, Jiasong; Twa, Michael; Emelianov, Stanislav Y.; Larin, Kirill V.

2015-06-01

In this study the dynamic behavior of a layered viscoelastic medium in response to the harmonic and impulsive acoustic radiation force applied to its surface was investigated both theoretically and experimentally. An analytical solution for a layered viscoelastic compressible medium in frequency and time domains was obtained using the Hankel transform. A special incompressible case was considered to model soft biological tissues. To verify our theoretical model, experiments were performed using tissue-like gel-based phantoms with varying mechanical properties. A 3.5 MHz single-element focused ultrasound transducer was used to apply the radiation force at the surface of the phantoms. A phase-sensitive optical coherence tomography system was used to track the displacements of the phantom surface. Theoretically predicted displacements were compared with experimental measurements. The role of the depth dependence of the elastic properties of a medium in its response to an acoustic pulse at the surface was studied. It was shown that the low-frequency vibrations at the surface are more sensitive to the deep layers than high-frequency ones. Therefore, the proposed model in combination with spectral analysis can be used to evaluate depth-dependent distribution of the mechanical properties based on the measurements of the surface deformation.

Allergic Sensitization through the Airway Primes Th17-dependent Neutrophilia and Airway Hyperresponsiveness

PubMed Central

Wilson, Rhonda H.; Whitehead, Gregory S.; Nakano, Hideki; Free, Meghan E.; Kolls, Jay K.; Cook, Donald N.

2009-01-01

Rationale: In humans, immune responses to inhaled aeroallergens develop in the lung and draining lymph nodes. Many animal models of asthma bypass this route and instead use intraperitoneal injections of allergen using aluminum hydroxide as an adjuvant. Objectives: We investigated whether allergic sensitization through the airway elicits immune responses qualitatively different than those arising in the peritoneum. Methods: Mice were sensitized to allergen through the airway using low-dose LPS as an adjuvant, or through the peritoneum using aluminum hydroxide as an adjuvant. After a single allergen challenge, ELISA and flow cytometry were used to measure cytokines and leukocyte subsets. Invasive measurements of airway resistance were used to measure allergen-induced airway hyperreactivity (AHR). Measurements and Main Results: Sensitization through the peritoneum primed strong Th2 responses and eosinophilia, but not AHR, after a single allergen challenge. By contrast, allergic sensitization through the airway primed only modest Th2 responses, but strong Th17 responses. Th17 cells homed to the lung and released IL-17 into the airway on subsequent encounter with inhaled allergen. As a result, these mice developed IL-17–dependent airway neutrophilia and AHR. This AHR was neutrophil-dependent because it was abrogated in CXCR2-deficient mice and also in wild-type mice receiving a neutrophil-depleting antibody. Individually, neither IL-17 nor ongoing Th2 responses were sufficient to confer AHR, but together they acted synergistically to promote neutrophil recruitment, eosinophil recruitment and AHR. Conclusions: Allergic sensitization through the airway primes modest Th2 responses but strong Th17 responses that promote airway neutrophilia and acute AHR. These findings support a causal role for neutrophils in severe asthma. PMID:19661246

Careers in Airway Science.

ERIC Educational Resources Information Center

Federal Aviation Administration (DOT), Washington, DC.

The Federal Aviation Administration (FAA) has initiated the Airway Science curriculum as a method of preparing the next generation of aviation technicians and managers. This document: (1) discusses the FAA's role in the Airway Science program; (2) describes some of the career fields that FAA offers to Airway Science graduates (air traffic control…

Evaluation of parameterization for turbulent fluxes of momentum and heat in stably stratified surface layers

NASA Astrophysics Data System (ADS)

Sodemann, H.; Foken, Th.

2003-04-01

General Circulation Models calculate the energy exchange between surface and atmosphere by means of parameterisations for turbulent fluxes of momentum and heat in the surface layer. However, currently implemented parameterisations after Louis (1979) create large discrepancies between predictions and observational data, especially in stably stratified surface layers. This work evaluates a new surface layer parameterisation proposed by Zilitinkevich et al. (2002), which was specifically developed to improve energy flux predictions in stable stratification. The evaluation comprises a detailed study of important surface layer characteristics, a sensitivity study of the parameterisation, and a direct comparison to observational data from Antarctica and predictions by the Louis (1979) parameterisation. The stability structure of the stable surface layer was found to be very complex, and strongly influenced fluxes in the surface layer. The sensitivity study revealed that the new parameterisation depends strongly on the ratio between roughness length and roughness temperature, which were both observed to be very variable parameters. The comparison between predictions and measurements showed good agreement for momentum fluxes, but large discrepancies for heat fluxes. A stability dependent evaluation of selected data showed better agreement for the new parameterisation of Zilitinkevich et al. (2002) than for the Louis (1979) scheme. Nevertheless, this comparison underlines the need for more detailed and physically sound concepts for parameterisations of heat fluxes in stably stratified surface layers. Zilitinkevich, S. S., V. Perov and J. C. King (2002). "Near-surface turbulent fluxes in stable stratification: Calculation techniques for use in General Circulation Models." Q. J. R. Meteorol. Soc. 128(583): 1571--1587. Louis, J. F. (1979). "A Parametric Model of Vertical Eddy Fluxes in the Atmosphere." Bound.-Layer Meteor. 17(2): 187--202.

Polyethylene imine/graphene oxide layer-by-layer surface functionalization for significantly improved limit of detection and binding kinetics of immunoassays on acrylate surfaces.

PubMed

Miyazaki, Celina M; Mishra, Rohit; Kinahan, David J; Ferreira, Marystela; Ducrée, Jens

2017-10-01

Antibody immobilization on polymeric substrates is a key manufacturing step for microfluidic devices that implement sample-to-answer automation of immunoassays. In this work, a simple and versatile method to bio-functionalize poly(methylmethacrylate) (PMMA), a common material of such "Lab-on-a-Chip" systems, is proposed; using the Layer-by-Layer (LbL) technique, we assemble nanostructured thin films of poly(ethylene imine) (PEI) and graphene oxide (GO). The wettability of PMMA surfaces was significantly augmented by the surface treatment with (PEI/GO) 5 film, with an 81% reduction of the contact angle, while the surface roughness increased by 600%, thus clearly enhancing wettability and antibody binding capacity. When applied to enzyme-linked immunosorbent assays (ELISAs), the limit of detection of PMMA surface was notably improved from 340pgmL -1 on commercial grade polystyrene (PS) and 230pgmL -1 on plain PMMA surfaces to 130pgmL -1 on (PEI/GO) 5 treated PMMA. Furthermore, the accelerated antibody adsorption kinetics on the LbL films of GO allowed to substantially shorten incubation times, e.g. for anti-rat IgG adsorption from 2h down to 15min on conventional and treated surfaces, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Critical CuI buffer layer surface density for organic molecular crystal orientation change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Kwangseok; Kim, Jong Beom; Lee, Dong Ryeol, E-mail: drlee@ssu.ac.kr

We have determined the critical surface density of the CuI buffer layer inserted to change the preferred orientation of copper phthalocyanine (CuPc) crystals grown on the buffer layer. X-ray reflectivity measurements were performed to obtain the density profiles of the buffer layers and out-of-plane and 2D grazing-incidence X-ray diffraction measurements were performed to determine the preferred orientations of the molecular crystals. Remarkably, it was found that the preferred orientation of the CuPc film is completely changed from edge-on (1 0 0) to face-on (1 1 −2) by a CuI buffer layer with a very low surface density, so low thatmore » a large proportion of the substrate surface is bare.« less

Cloud layer thicknesses from a combination of surface and upper-air observations

NASA Technical Reports Server (NTRS)

Poore, Kirk D.; Wang, Junhong; Rossow, William B.

1995-01-01

Cloud layer thicknesses are derived from base and top altitudes by combining 14 years (1975-1988) of surface and upper-air observations at 63 sites in the Northern Hemisphere. Rawinsonde observations are employed to determine the locations of cloud-layer top and base by testing for dewpoint temperature depressions below some threshold value. Surface observations serve as quality checks on the rawinsonde-determined cloud properties and provide cloud amount and cloud-type information. The dataset provides layer-cloud amount, cloud type, high, middle, or low height classes, cloud-top heights, base heights and layer thicknesses, covering a range of latitudes from 0 deg to 80 deg N. All data comes from land sites: 34 are located in continental interiors, 14 are near coasts, and 15 are on islands. The uncertainties in the derived cloud properties are discussed. For clouds classified by low-, mid-, and high-top altitudes, there are strong latitudinal and seasonal variations in the layer thickness only for high clouds. High-cloud layer thickness increases with latitude and exhibits different seasonal variations in different latitude zones: in summer, high-cloud layer thickness is a maximum in the Tropics but a minimum at high latitudes. For clouds classified into three types by base altitude or into six standard morphological types, latitudinal and seasonal variations in layer thickness are very small. The thickness of the clear surface layer decreases with latitude and reaches a summer minimum in the Tropics and summer maximum at higher latitudes over land, but does not vary much over the ocean. Tropical clouds occur in three base-altitude groups and the layer thickness of each group increases linearly with top altitude. Extratropical clouds exhibit two groups, one with layer thickness proportional to their cloud-top altitude and one with small (less than or equal to 1000 m) layer thickness independent of cloud-top altitude.

Surface passivation of InP solar cells with InAlAs layers

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Flood, Dennis J.; Landis, Geoffrey A.

1993-01-01

The efficiency of indium phosphide solar cells is limited by high values of surface recombination. The effect of a lattice-matched In(0.52)Al(0.48)As window layer material for InP solar cells, using the numerical code PC-1D is investigated. It was found that the use of InAlAs layer significantly enhances the p(+)n cell efficiency, while no appreciable improvement is seen for n(+)p cells. The conduction band energy discontinuity at the heterojunction helps in improving the surface recombination. An optimally designed InP cell efficiency improves from 15.4 percent to 23 percent AMO for a 10 nm thick InAlAs layer. The efficiency improvement reduces with increase in InAlAs layer thickness, due to light absorption in the window layer.

Investigation of pulmonary acoustic simulation: comparing airway model generation techniques

NASA Astrophysics Data System (ADS)

Henry, Brian; Dai, Zoujun; Peng, Ying; Mansy, Hansen A.; Sandler, Richard H.; Royston, Thomas

2014-03-01

Alterations in the structure and function of the pulmonary system that occur in disease or injury often give rise to measurable spectral, spatial and/or temporal changes in lung sound production and transmission. These changes, if properly quantified, might provide additional information about the etiology, severity and location of trauma, injury, or pathology. With this in mind, the authors are developing a comprehensive computer simulation model of pulmonary acoustics, known as The Audible Human Project™. Its purpose is to improve our understanding of pulmonary acoustics and to aid in interpreting measurements of sound and vibration in the lungs generated by airway insonification, natural breath sounds, and external stimuli on the chest surface, such as that used in elastography. As a part of this development process, finite element (FE) models were constructed of an excised pig lung that also underwent experimental studies. Within these models, the complex airway structure was created via two methods: x-ray CT image segmentation and through an algorithmic means called Constrained Constructive Optimization (CCO). CCO was implemented to expedite the segmentation process, as airway segments can be grown digitally. These two approaches were used in FE simulations of the surface motion on the lung as a result of sound input into the trachea. Simulation results were compared to experimental measurements. By testing how close these models are to experimental measurements, we are evaluating whether CCO can be used as a means to efficiently construct physiologically relevant airway trees.

Simvastatin inhibits smoke-induced airway epithelial injury: implications for COPD therapy.

PubMed

Davis, Benjamin B; Zeki, Amir A; Bratt, Jennifer M; Wang, Lei; Filosto, Simone; Walby, William F; Kenyon, Nicholas J; Goldkorn, Tzipora; Schelegle, Edward S; Pinkerton, Kent E

2013-08-01

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death. The statin drugs may have therapeutic potential in respiratory diseases such as COPD, but whether they prevent bronchial epithelial injury is unknown. We hypothesised that simvastatin attenuates acute tobacco smoke-induced neutrophilic lung inflammation and airway epithelial injury. Spontaneously hypertensive rats were given simvastatin (20 mg·kg(-1) i.p.) daily for either 7 days prior to tobacco smoke exposure and during 3 days of smoke exposure, or only during tobacco smoke exposure. Pretreatment with simvastatin prior to and continued throughout smoke exposure reduced the total influx of leukocytes, neutrophils and macrophages into the lung and airways. Simvastatin attenuated tobacco smoke-induced cellular infiltration into lung parenchymal and airway subepithelial and interstitial spaces. 1 week of simvastatin pretreatment almost completely prevented smoke-induced denudation of the airway epithelial layer, while simvastatin given only concurrently with the smoke exposure had no effect. Simvastatin may be a novel adjunctive therapy for smoke-induced lung diseases, such as COPD. Given the need for statin pretreatment there may be a critical process of conditioning that is necessary for statins' anti-inflammatory effects. Future work is needed to elucidate the mechanisms of this statin protective effect.

Modification of surface oxide layers of titanium targets for increasing lifetime of neutron tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zakharov, A. M., E-mail: zam@plasma.mephi.ru; Dvoichenkova, O. A.; Evsin, A. E.

The peculiarities of interaction of hydrogen ions with a titanium target and its surface oxide layer were studied. Two ways of modification of the surface oxide layers of titanium targets for increasing the lifetime of neutron tubes were proposed: (1) deposition of an yttrium oxide barrier layer on the target surface; (2) implementation of neutron tube work regime in which the target is irradiated with ions with energies lower than 1000 eV between high-energy ion irradiation pulses.

Aspergillus fumigatus Infection-Induced Neutrophil Recruitment and Location in the Conducting Airway of Immunocompetent, Neutropenic, and Immunosuppressed Mice.

PubMed

Shevchenko, Marina A; Bogorodskiy, Andrey O; Troyanova, Natalia I; Servuli, Ekaterina A; Bolkhovitina, Elena L; Büldt, Georg; Fahlke, Christoph; Gordeliy, Valentin I; Gensch, Thomas; Borshchevskiy, Valentin I; Sapozhnikov, Alexander M

2018-01-01

Susceptibility to fungal infection is commonly associated with impaired neutrophil responses. To study the mechanisms underlying this association, we investigated neutrophil recruitment to the conducting airway wall after Aspergillus fumigatus conidium inhalation in mouse models of drug-induced immunosuppression and antibody-mediated neutrophil depletion (neutropenia) by performing three-dimensional confocal laser-scanning microscopy of whole-mount primary bronchus specimens. Actin staining enabled visualization of the epithelial and smooth muscle layers that mark the airway wall. Gr-1 + or Ly6G + neutrophils located between the epithelium and smooth muscles were considered airway wall neutrophils. The number of airway wall neutrophils for immunocompetent, immunosuppressed, and neutropenic mice before and 6 h after A. fumigatus infection were analyzed and compared. Our results show that the number of conducting airway wall neutrophils in immunocompetent mice significantly increased upon inflammation, while a dramatic reduction in this number was observed following immunosuppression and neutropenia. Interestingly, a slight increase in the infiltration of neutrophils into the airway wall was detected as a result of infection, even in immunosuppressed and neutropenic mice. Taken together, these data indicate that neutrophils are present in intact conducting airway walls and the number elevates upon A. fumigatus infection. Conducting airway wall neutrophils are affected by both neutropenia and immunosuppression.

Aspergillus fumigatus Infection-Induced Neutrophil Recruitment and Location in the Conducting Airway of Immunocompetent, Neutropenic, and Immunosuppressed Mice

PubMed Central

Bogorodskiy, Andrey O.; Troyanova, Natalia I.; Servuli, Ekaterina A.; Bolkhovitina, Elena L.; Büldt, Georg; Fahlke, Christoph; Gordeliy, Valentin I.; Gensch, Thomas; Sapozhnikov, Alexander M.

2018-01-01

Susceptibility to fungal infection is commonly associated with impaired neutrophil responses. To study the mechanisms underlying this association, we investigated neutrophil recruitment to the conducting airway wall after Aspergillus fumigatus conidium inhalation in mouse models of drug-induced immunosuppression and antibody-mediated neutrophil depletion (neutropenia) by performing three-dimensional confocal laser-scanning microscopy of whole-mount primary bronchus specimens. Actin staining enabled visualization of the epithelial and smooth muscle layers that mark the airway wall. Gr-1+ or Ly6G+ neutrophils located between the epithelium and smooth muscles were considered airway wall neutrophils. The number of airway wall neutrophils for immunocompetent, immunosuppressed, and neutropenic mice before and 6 h after A. fumigatus infection were analyzed and compared. Our results show that the number of conducting airway wall neutrophils in immunocompetent mice significantly increased upon inflammation, while a dramatic reduction in this number was observed following immunosuppression and neutropenia. Interestingly, a slight increase in the infiltration of neutrophils into the airway wall was detected as a result of infection, even in immunosuppressed and neutropenic mice. Taken together, these data indicate that neutrophils are present in intact conducting airway walls and the number elevates upon A. fumigatus infection. Conducting airway wall neutrophils are affected by both neutropenia and immunosuppression. PMID:29577051

Tuning plasmons layer-by-layer for quantitative colloidal sensing with surface-enhanced Raman spectroscopy.

PubMed

Anderson, William J; Nowinska, Kamila; Hutter, Tanya; Mahajan, Sumeet; Fischlechner, Martin

2018-04-19

Surface-enhanced Raman spectroscopy (SERS) is well known for its high sensitivity that emerges due to the plasmonic enhancement of electric fields typically on gold and silver nanostructures. However, difficulties associated with the preparation of nanostructured substrates with uniform and reproducible features limit reliability and quantitation using SERS measurements. In this work we use layer-by-layer (LbL) self-assembly to incorporate multiple functional building blocks of collaborative assemblies of nanoparticles on colloidal spheres to fabricate SERS sensors. Gold nanoparticles (AuNPs) are packaged in discrete layers, effectively 'freezing nano-gaps', on spherical colloidal cores to achieve multifunctionality and reproducible sensing. Coupling between layers tunes the plasmon resonance for optimum SERS signal generation to achieve a 10 nM limit of detection. Significantly, using the layer-by-layer construction, SERS-active AuNP layers are spaced out and thus optically isolated. This uniquely allows the creation of an internal standard within each colloidal sensor to enable highly reproducible self-calibrated sensing. By using 4-mercaptobenzoic acid (4-MBA) as the internal standard adenine concentrations are quantified to an accuracy of 92.6-99.5%. Our versatile approach paves the way for rationally designed yet quantitative colloidal SERS sensors and their use in a variety of sensing applications.

Microtubules Enable the Planar Cell Polarity of Airway Cilia

PubMed Central

Vladar, Eszter K.; Bayly, Roy D.; Sangoram, Ashvin; Scott, Matthew P.; Axelrod, Jeffrey D.

2012-01-01

Summary Background Airway cilia must be physically oriented along the longitudinal tissue axis for concerted, directional motility that is essential for proper mucociliary clearance. Results We show that Planar Cell Polarity (PCP) signaling specifies directionality and orients respiratory cilia. Within all airway epithelial cells a conserved set of PCP proteins shows interdependent, asymmetric junctional localization; non-autonomous signaling coordinates polarization between cells; and a polarized microtubule (MT) network is likely required for asymmetric PCP protein localization. We find that basal bodies dock after polarity of PCP proteins is established, are polarized nearly simultaneously, and refinement of basal body/cilium orientation continues during airway epithelial development. Unique to mature multiciliated cells, we identify PCP-regulated, planar polarized MTs that originate from basal bodies and interact, via their plus ends, with membrane domains associated with the PCP proteins Frizzled and Dishevelled. Disruption of MTs leads to misoriented cilia. Conclusions A conserved PCP pathway orients airway cilia by communicating polarity information from asymmetric membrane domains at the apical junctions, through MTs, to orient the MT and actin based network of ciliary basal bodies below the apical surface. PMID:23122850

Mechanics of airway and alveolar collapse in human breath-hold diving.

PubMed

Fitz-Clarke, John R

2007-11-15

A computational model of the human respiratory tract was developed to study airway and alveolar compression and re-expansion during deep breath-hold dives. The model incorporates the chest wall, supraglottic airway, trachea, branched airway tree, and elastic alveoli assigned time-dependent surfactant properties. Total lung collapse with degassing of all alveoli is predicted to occur around 235 m, much deeper than estimates for aquatic mammals. Hysteresis of the pressure-volume loop increases with maximum diving depth due to progressive alveolar collapse. Reopening of alveoli occurs stochastically as airway pressure overcomes adhesive and compressive forces on ascent. Surface area for gas exchange vanishes at collapse depth, implying that the risk of decompression sickness should reach a plateau beyond this depth. Pulmonary capillary transmural stresses cannot increase after local alveolar collapse. Consolidation of lung parenchyma might provide protection from capillary injury or leakage caused by vascular engorgement due to outward chest wall recoil at extreme depths.

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1992-01-01

A microporous structure with layered interstitial surface treatments, and the method and apparatus for its preparation are disclosed. The structure is prepared by sequentially subjecting a uniformly surface treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1994-01-01

A microporous structure with layered interstitial surface treatments, and method and apparatus for preparation thereof is presented. The structure is prepared by sequentially subjecting a uniformly surface-treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Relapsing polychondritis and airway involvement.

PubMed

Ernst, Armin; Rafeq, Samaan; Boiselle, Phillip; Sung, Arthur; Reddy, Chakravarthy; Michaud, Gaetane; Majid, Adnan; Herth, Felix J F; Trentham, David

2009-04-01

To assess the prevalence and characteristics of airway involvement in relapsing polychondritis (RP). Retrospective chart review and data analysis of RP patients seen in the Rheumatology Clinic and the Complex Airway Center at Beth Israel Deaconess Medical Center from January 2004 through February 2008. RP was diagnosed in 145 patients. Thirty-one patients had airway involvement, a prevalence of 21%. Twenty-two patients were women (70%), and they were between 11 and 61 years of age (median age, 42 years) at the time of first symptoms. Airway symptoms were the first manifestation of disease in 17 patients (54%). Dyspnea was the most common symptom in 20 patients (64%), followed by cough, stridor, and hoarseness. Airway problems included the following: subglottic stenosis (n = 8; 26%); focal and diffuse malacia (n = 15; 48%); and focal stenosis in different areas of the bronchial tree in the rest of the patients. Twelve patients (40%) required and underwent intervention including balloon dilatation, stent placement, tracheotomy, or a combination of the above with good success. The majority of patients experienced improvement in airway symptoms after intervention. One patient died during the follow-up period from the progression of airway disease. The rest of the patients continue to undergo periodic evaluation and intervention. In this largest cohort described in the English language literature, we found symptomatic airway involvement in RP to be common and at times severe. The nature of airway problems is diverse, with tracheomalacia being the most common. Airway intervention is frequently required and in experienced hands results in symptom improvement.

Airway recovery after face transplantation.

PubMed

Fischer, Sebastian; Wallins, Joe S; Bueno, Ericka M; Kueckelhaus, Maximilian; Chandawarkar, Akash; Diaz-Siso, J Rodrigo; Larson, Allison; Murphy, George F; Annino, Donald J; Caterson, Edward J; Pomahac, Bohdan

2014-12-01

Severe facial injuries can compromise the upper airway by reducing airway volume, obstructing or obliterating the nasal passage, and interfering with oral airflow. Besides the significant impact on quality of life, upper airway impairments can have life-threatening or life-altering consequences. The authors evaluated improvements in functional airway after face transplantation. Between 2009 and 2011, four patients underwent face transplantation at the authors' institution, the Brigham and Women's Hospital. Patients were examined preoperatively and postoperatively and their records reviewed for upper airway infections and sleeping disorders. The nasal mucosa was biopsied after face transplantation and analyzed using scanning electron microscopy. Volumetric imaging software was used to evaluate computed tomographic scans of the upper airway and assess airway volume changes before and after transplantation. Before transplantation, two patients presented an exposed naked nasal cavity and two suffered from occlusion of the nasal passage. Two patients required tracheostomy tubes and one had a prosthetic nose. Sleeping disorders were seen in three patients, and chronic cough was diagnosed in one. After transplantation, there was no significant improvement in sleeping disorders. The incidence of sinusitis increased because of mechanical interference of the donor septum and disappeared after surgical correction. All patients were decannulated after transplantation and were capable of nose breathing. Scanning electron micrographs of the respiratory mucosa revealed viable tissue capable of mucin production. Airway volume significantly increased in all patients. Face transplantation successfully restored the upper airway in four patients. Unhindered nasal breathing, viable respiratory mucosa, and a significant increase in airway volume contributed to tracheostomy decannulation.

High Reynolds number rough wall turbulent boundary layer experiments using Braille surfaces

NASA Astrophysics Data System (ADS)

Harris, Michael; Monty, Jason; Nova, Todd; Allen, James; Chong, Min

2007-11-01

This paper details smooth, transitional and fully rough turbulent boundary layer experiments in the New Mexico State high Reynolds number rough wall wind tunnel. The initial surface tested was generated with a Braille printer and consisted of an uniform array of Braille points. The average point height being 0.5mm, the spacing between the points in the span was 0.5mm and the surface consisted of span wise rows separated by 4mm. The wavelength to peak ratio was 8:1. The boundary layer thickness at the measurement location was 190mm giving a large separation of roughness height to layer thickness. The maximum friction velocity was uτ=1.5m/s at Rex=3.8 x10^7. Results for the skin friction co-efficient show that this surface follows a Nikuradse type inflectional curve and that Townsends outer layer similarity hypothesis is valid for rough wall flows with a large separation of scales. Mean flow and turbulence statistics will be presented.

Muc5b is required for airway defence

NASA Astrophysics Data System (ADS)

Roy, Michelle G.; Livraghi-Butrico, Alessandra; Fletcher, Ashley A.; McElwee, Melissa M.; Evans, Scott E.; Boerner, Ryan M.; Alexander, Samantha N.; Bellinghausen, Lindsey K.; Song, Alfred S.; Petrova, Youlia M.; Tuvim, Michael J.; Adachi, Roberto; Romo, Irlanda; Bordt, Andrea S.; Bowden, M. Gabriela; Sisson, Joseph H.; Woodruff, Prescott G.; Thornton, David J.; Rousseau, Karine; de La Garza, Maria M.; Moghaddam, Seyed J.; Karmouty-Quintana, Harry; Blackburn, Michael R.; Drouin, Scott M.; Davis, C. William; Terrell, Kristy A.; Grubb, Barbara R.; O'Neal, Wanda K.; Flores, Sonia C.; Cota-Gomez, Adela; Lozupone, Catherine A.; Donnelly, Jody M.; Watson, Alan M.; Hennessy, Corinne E.; Keith, Rebecca C.; Yang, Ivana V.; Barthel, Lea; Henson, Peter M.; Janssen, William J.; Schwartz, David A.; Boucher, Richard C.; Dickey, Burton F.; Evans, Christopher M.

2014-01-01

Respiratory surfaces are exposed to billions of particulates and pathogens daily. A protective mucus barrier traps and eliminates them through mucociliary clearance (MCC). However, excessive mucus contributes to transient respiratory infections and to the pathogenesis of numerous respiratory diseases. MUC5AC and MUC5B are evolutionarily conserved genes that encode structurally related mucin glycoproteins, the principal macromolecules in airway mucus. Genetic variants are linked to diverse lung diseases, but specific roles for MUC5AC and MUC5B in MCC, and the lasting effects of their inhibition, are unknown. Here we show that mouse Muc5b (but not Muc5ac) is required for MCC, for controlling infections in the airways and middle ear, and for maintaining immune homeostasis in mouse lungs, whereas Muc5ac is dispensable. Muc5b deficiency caused materials to accumulate in upper and lower airways. This defect led to chronic infection by multiple bacterial species, including Staphylococcus aureus, and to inflammation that failed to resolve normally. Apoptotic macrophages accumulated, phagocytosis was impaired, and interleukin-23 (IL-23) production was reduced in Muc5b-/- mice. By contrast, in mice that transgenically overexpress Muc5b, macrophage functions improved. Existing dogma defines mucous phenotypes in asthma and chronic obstructive pulmonary disease (COPD) as driven by increased MUC5AC, with MUC5B levels either unaffected or increased in expectorated sputum. However, in many patients, MUC5B production at airway surfaces decreases by as much as 90%. By distinguishing a specific role for Muc5b in MCC, and by determining its impact on bacterial infections and inflammation in mice, our results provide a refined framework for designing targeted therapies to control mucin secretion and restore MCC.

Surface modification of upconverting nanoparticles by layer-by-layer assembled polyelectrolytes and metal ions.

PubMed

Palo, Emilia; Salomäki, Mikko; Lastusaari, Mika

2017-12-15

Modificating and protecting the upconversion luminescence nanoparticles is important for their potential in various applications. In this work we demonstrate successful coating of the nanoparticles by a simple layer-by-layer method using negatively charged polyelectrolytes and neodymium ions. The layer fabrication conditions such as number of the bilayers, solution concentrations and selected polyelectrolytes were studied to find the most suitable conditions for the process. The bilayers were characterized and the presence of the desired components was studied and confirmed by various methods. In addition, the upconversion luminescence of the bilayered nanoparticles was studied to see the effect of the surface modification on the overall intensity. It was observed that with selected deposition concentrations the bilayer successfully shielded the particle resulting in stronger upconversion luminescence. The layer-by-layer method offers multiple possibilities to control the bilayer growth even further and thus gives promises that the use of upconverting nanoparticles in applications could become even easier with less modification steps in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Experimental and computational studies of sound transmission in a branching airway network embedded in a compliant viscoelastic medium

NASA Astrophysics Data System (ADS)

Dai, Zoujun; Peng, Ying; Mansy, Hansen A.; Sandler, Richard H.; Royston, Thomas J.

2015-03-01

Breath sounds are often used to aid in the diagnosis of pulmonary disease. Mechanical and numerical models could be used to enhance our understanding of relevant sound transmission phenomena. Sound transmission in an airway mimicking phantom was investigated using a mechanical model with a branching airway network embedded in a compliant viscoelastic medium. The Horsfield self-consistent model for the bronchial tree was adopted to topologically couple the individual airway segments into the branching airway network. The acoustics of the bifurcating airway segments were measured by microphones and calculated analytically. Airway phantom surface motion was measured using scanning laser Doppler vibrometry. Finite element simulations of sound transmission in the airway phantom were performed. Good agreement was achieved between experiments and simulations. The validated computational approach can provide insight into sound transmission simulations in real lungs.

Nanoscale surface modification of Li-rich layered oxides for high-capacity cathodes in Li-ion batteries

NASA Astrophysics Data System (ADS)

Lan, Xiwei; Xin, Yue; Wang, Libin; Hu, Xianluo

2018-03-01

Li-rich layered oxides (LLOs) have been developed as a high-capacity cathode material for Li-ion batteries, but the structural complexity and unique initial charging behavior lead to several problems including large initial capacity loss, capacity and voltage fading, poor cyclability, and inferior rate capability. Since the surface conditions are critical to electrochemical performance and the drawbacks, nanoscale surface modification for improving LLO's properties is a general strategy. This review mainly summarizes the surface modification of LLOs and classifies them into three types of surface pre-treatment, surface gradient doping, and surface coating. Surface pre-treatment usually introduces removal of Li2O for lower irreversible capacity while surface doping is aimed to stabilize the structure during electrochemical cycling. Surface coating layers with different properties, protective layers to suppress the interface side reaction, coating layers related to structural transformation, and electronic/ionic conductive layers for better rate capability, can avoid the shortcomings of LLOs. In addition to surface modification for performance enhancement, other strategies can also be investigated to achieve high-performance LLO-based cathode materials.

The nanostructure and microstructure of SiC surface layers deposited by MWCVD and ECRCVD

NASA Astrophysics Data System (ADS)

Dul, K.; Jonas, S.; Handke, B.

2017-12-01

Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) have been used to investigate ex-situ the surface topography of SiC layers deposited on Si(100) by Microwave Chemical Vapour Deposition (MWCVD) -S1,S2 layers and Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) - layers S3,S4, using silane, methane, and hydrogen. The effects of sample temperature and gas flow on the nanostructure and microstructure have been investigated. The nanostructure was described by three-dimensional surface roughness analysis based on digital image processing, which gives a tool to quantify different aspects of surface features. A total of 13 different numerical parameters used to describe the surface topography were used. The scanning electron image (SEM) of the microstructure of layers S1, S2, and S4 was similar, however, layer S3 was completely different; appearing like grains. Nonetheless, it can be seen that no grain boundary structure is present in the AFM images.

COMPUTER SIMULATIONS OF LUNG AIRWAY STRUCTURES USING DATA-DRIVEN SURFACE MODELING TECHNIQUES

EPA Science Inventory

ABSTRACT

Knowledge of human lung morphology is a subject critical to many areas of medicine. The visualization of lung structures naturally lends itself to computer graphics modeling due to the large number of airways involved and the complexities of the branching systems...

[Quality assurance in airway management: education and training for difficult airway management].

PubMed

Kaminoh, Yoshiroh

2006-01-01

Respiratory problem is one of the main causes of death or severe brain damage in perioperative period. Three major factors of respiratory problem are esophageal intubation, inadequate ventilation, and difficult airway. The wide spread of pulse oximeter and capnograph reduced the incidences of esophageal intubation and inadequate ventilation, but the difficult airway still occupies the large portion in the causes of adverse events during anesthesia. "Practice guideline for management of the difficult airway" was proposed by American Society of Anesthesiologists (ASA) in 1992 and 2002. Improvement of knowledge, technical skills, and cognitive skills are necessary for the education and training of the difficult airway management. "The practical seminar of difficult airway management (DAM practical seminar)" has been cosponsored by the Japanese Association of Medical Simulation (JAMS) in the 51 st and 52 nd annual meetings of Japanese Society of Anesthesiologists and the 24th annual meeting of Japanese Society for Clinical Anesthesia. The DAM practical seminar is composed of the lecture session for ASA difficult airway algorithm, the hands-on training session for technical skills, and the scenario-based training session for cognitive skills. Ninty six Japanese anesthesiologists have completed the DAM practical seminar in one year. "The DAM instructor course" should be immediately prepared to organize the seminar more frequently.

Highly improved passivation of c-Si surfaces using a gradient i a-Si:H layer

NASA Astrophysics Data System (ADS)

Lee, Soonil; Ahn, Jaehyun; Mathew, Leo; Rao, Rajesh; Zhang, Zhongjian; Kim, Jae Hyun; Banerjee, Sanjay K.; Yu, Edward T.

2018-04-01

Surface passivation using intrinsic a-Si:H (i a-Si:H) films plays a key role in high efficiency c-Si heterojunction solar cells. In this study, we demonstrate improved passivation quality using i a-Si:H films with a gradient-layered structure consisting of interfacial, transition, and capping layers deposited on c-Si surfaces. The H2 dilution ratio (R) during deposition was optimized individually for the interfacial and capping layers, which were separated by a transition layer for which R changed gradually between its values for the interfacial and capping layers. This approach yielded a significant reduction in surface carrier recombination, resulting in improvement of the minority carrier lifetime from 1480 μs for mono-layered i a-Si:H passivation to 2550 μs for the gradient-layered passivation approach.

Iron layer-dependent surface-enhanced raman scattering of hierarchical nanocap arrays

NASA Astrophysics Data System (ADS)

Chen, Lei; Sun, Huanhuan; Zhao, Yue; Gao, Renxian; Wang, Yaxin; Liu, Yang; Zhang, Yongjun; Hua, Zhong; Yang, Jinghai

2017-11-01

In this report, we fabricated the multi-layer Ag/Fe/Ag sandwich cap-shaped films on monolayer non-closed packed (ncp) polystyrene colloidal particle (PSCP) templates through a layer-by-layer (LBL) depositing method. This research focused on the surface-enhanced Raman scattering (SERS) effect of the thickness of the deposited Fe film which was controlled by the sputtering time. The SERS intensities were increased firstly, and then decreased as the thickness of Fe layer grows gradually, which is attributed to the charge transition from the Fermi level of the Ag NPs to Fe layer. The use of multi-layer Ag/Fe/Ag sandwich cap-shaped films enables us to evaluate the contribution of surface plasmon resonance and charge distribution between Ag and Fe to SERS enhancement. Our work introduced a novel system (Ag/Fe/Ag) for high performance SERS and extended the SERS application of Fe. Furthermore, we have designed the Ag/Fe/Ag SERS-active substrate as the immunoassay chip for quantitative determination of AFP-L3 which is the biomarker of hepatocellular carcinoma (HCC). The proposed research demonstrates that the SERS substrates with Ag/Fe/Ag sandwich cap-shaped arrays have a high sensitivity for bioassay.

Sound transmission in porcine thorax through airway insonification

PubMed Central

Dai, Zoujun; Mansy, Hansen A.; Henry, Brian M.; Sandler, Richard H.; Balk, Robert A.; Royston, Thomas J.

2015-01-01

Many pulmonary injuries and pathologies may lead to structural and functional changes in the lungs resulting in measurable sound transmission changes on the chest surface. Additionally, noninvasive imaging of externally driven mechanical wave motion in the chest (e.g., using magnetic resonance elastography) can provide information about lung structural property changes and, hence, may be of diagnostic value. In the present study, a comprehensive computational simulation (in silico) model was developed to simulate sound wave propagation in the airways, lung, and chest wall under normal and pneumothorax conditions. Experiments were carried out to validate the model. Here, sound waves with frequency content from 50 to 700 Hz were introduced into airways of five porcine subjects via an endotracheal tube, and transmitted waves were measured by scanning laser Doppler vibrometry at the chest wall surface. The computational model predictions of decreased sound transmission with pneumothorax were consistent with experimental measurements. The in silico model can also be used to visualize wave propagation inside and on the chest wall surface for other pulmonary pathologies, which may help in developing and interpreting diagnostic procedures that utilize sound and vibration. PMID:26280512

Sound transmission in porcine thorax through airway insonification.

PubMed

Peng, Ying; Dai, Zoujun; Mansy, Hansen A; Henry, Brian M; Sandler, Richard H; Balk, Robert A; Royston, Thomas J

2016-04-01

Many pulmonary injuries and pathologies may lead to structural and functional changes in the lungs resulting in measurable sound transmission changes on the chest surface. Additionally, noninvasive imaging of externally driven mechanical wave motion in the chest (e.g., using magnetic resonance elastography) can provide information about lung structural property changes and, hence, may be of diagnostic value. In the present study, a comprehensive computational simulation (in silico) model was developed to simulate sound wave propagation in the airways, lung, and chest wall under normal and pneumothorax conditions. Experiments were carried out to validate the model. Here, sound waves with frequency content from 50 to 700 Hz were introduced into airways of five porcine subjects via an endotracheal tube, and transmitted waves were measured by scanning laser Doppler vibrometry at the chest wall surface. The computational model predictions of decreased sound transmission with pneumothorax were consistent with experimental measurements. The in silico model can also be used to visualize wave propagation inside and on the chest wall surface for other pulmonary pathologies, which may help in developing and interpreting diagnostic procedures that utilize sound and vibration.

Airway malacia in children with achondroplasia.

PubMed

Dessoffy, Kimberly E; Modaff, Peggy; Pauli, Richard M

2014-02-01

This study was undertaken to assess the frequency of airway malacia in infants and young children with achondroplasia, a population well known to be at risk for a variety of respiratory problems. We also wished to evaluate what, if any, contribution airway malacia makes to the complex respiratory issues that may be present in those with achondroplasia. Retrospective chart review of all infants and young children with achondroplasia who were assessed through the Midwest Regional Bone Dysplasia Clinics from 1985 through 2012 (n = 236) was completed. Records of comprehensive clinical examinations, polysomnographic assessments, and airway visualization were reviewed and abstracted using a data collection form. Analyses were completed comparing the group with and those without evidence for airway malacia. Thirteen of 236 patients (5.5%) were found to have airway malacia. Most of those affected had lower airway involvement (9/13). The presence of airway malacia was correlated with an increased occurrence of obstructive sleep apnea as well as need for oxygen supplementation, airway surgeries and tracheostomy placement. Although estimates of the frequency of airway malacia in the general population are limited, its frequency in children with achondroplasia appears to be much higher than any published general population estimate. The presence of airway malacia appears to confound other breathing abnormalities in this population and results in the need for more invasive airway treatments. © 2013 Wiley Periodicals, Inc.

Extraglottic airway devices: technology update.

PubMed

Sharma, Bimla; Sahai, Chand; Sood, Jayashree

2017-01-01

Extraglottic airway devices (EADs) have revolutionized the field of airway management. The invention of the laryngeal mask airway was a game changer, and since then, there have been several innovations to improve the EADs in design, functionality, safety and construction material. These have ranged from changes in the shape of the mask, number of cuffs and material used, like rubber, polyvinylchloride and latex. Phthalates, which were added to the construction material in order to increase device flexibility, were later omitted when this chemical was found to have serious adverse reproductive outcomes. The various designs brought out by numerous companies manufacturing EADs resulted in the addition of several devices to the airway market. These airway devices were put to use, many of them with inadequate or no evidence base regarding their efficacy and safety. To reduce the possibility of compromising the safety of the patient, the Difficult Airway Society (DAS) formed the Airway Device Evaluation Project Team (ADEPT) to strengthen the evidence base for airway equipment and vet the new extraglottic devices. A preuse careful analysis of the design and structure may help in better understanding of the functionality of a particular device. In the meantime, the search for the ideal EAD continues.

Layer uniformity in glucose oxidase immobilization on SiO 2 surfaces

NASA Astrophysics Data System (ADS)

Libertino, Sebania; Scandurra, Antonino; Aiello, Venera; Giannazzo, Filippo; Sinatra, Fulvia; Renis, Marcella; Fichera, Manuela

2007-09-01

The goal of this work was the characterization, step by step, of the enzyme glucose oxidase (GOx) immobilization on silicon oxide surfaces, mainly by means of X-Ray photoelectron spectroscopy (XPS). The immobilization protocol consists of four steps: oxide activation, silanization, linker molecule deposition and GOx immobilization. The linker molecule, glutaraldehyde (GA) in this study, must be able to form a uniform layer on the sample surface in order to maximize the sites available for enzyme bonding and achieve the best enzyme deposition. Using a thin SiO 2 layer grown on Si wafers and following the XPS Si2p signal of the Si substrate during the immobilization steps, we demonstrated both the glutaraldehyde layer uniformity and the possibility to use XPS to monitor thin layer uniformity. In fact, the XPS substrate signal, not shielded by the oxide, is suppressed only when a uniform layer is deposited. The enzyme correct immobilization was monitored using the XPS C1s and N1s signals. Atomic force microscopy (AFM) measurements carried out on the same samples confirmed the results.

Atomic Layer-Deposited TiO2 Coatings on NiTi Surface

NASA Astrophysics Data System (ADS)

Vokoun, D.; Racek, J.; Kadeřávek, L.; Kei, C. C.; Yu, Y. S.; Klimša, L.; Šittner, P.

2018-02-01

NiTi shape-memory alloys may release poisonous Ni ions at the alloys' surface. In an attempt to prepare a well-performing surface layer on an NiTi sample, the thermally grown TiO2 layer, which formed during the heat treatment of NiTi, was removed and replaced with a new TiO2 layer prepared using the atomic layer deposition (ALD) method. Using x-ray photoelectron spectroscopy, it was found that the ALD layer prepared at as low a temperature as 100 °C contained Ti in oxidation states + 4 and + 3. As for static corrosion properties of the ALD-coated NiTi samples, they further improved compared to those covered by thermally grown oxide. The corrosion rate of samples with thermally grown oxide was 1.05 × 10-5 mm/year, whereas the corrosion rate of the ALD-coated samples turned out to be about five times lower. However, cracking of the ALD coating occurred at about 1.5% strain during the superelastic mechanical loading in tension taking place via the propagation of a localized martensite band.

Formation of pentacene wetting layer on the SiO2 surface and charge trap in the wetting layer.

PubMed

Kim, Chaeho; Jeon, D

2008-09-01

We studied the early-stage growth of vacuum-evaporated pentacene film on a native SiO(2) surface using atomic force microscopy and in-situ spectroscopic ellipsometry. Pentacene deposition prompted an immediate change in the ellipsometry spectra, but atomic force microscopy images of the early stage films did not show a pentacene-related morphology other than the decrease in the surface roughness. This suggested that a thin pentacene wetting layer was formed by pentacene molecules lying on the surface before the crystalline islands nucleated. Growth simulation based on the in situ spectroscopic ellipsometry spectra supported this conclusion. Scanning capacitance microscopy measurement indicated the existence of trapped charges in the SiO(2) and pentacene wetting layer.

Self-Assembled Layering of Magnetic Nanoparticles in a Ferrofluid on Silicon Surfaces.

PubMed

Theis-Bröhl, Katharina; Vreeland, Erika C; Gomez, Andrew; Huber, Dale L; Saini, Apurve; Wolff, Max; Maranville, Brian B; Brok, Erik; Krycka, Kathryn L; Dura, Joseph A; Borchers, Julie A

2018-02-07

This article describes the three-dimensional self-assembly of monodisperse colloidal magnetite nanoparticles (NPs) from a dilute water-based ferrofluid onto a silicon surface and the dependence of the resultant magnetic structure on the applied field. The NPs assemble into close-packed layers on the surface followed by more loosely packed ones. The magnetic field-dependent magnetization of the individual NP layers depends on both the rotational freedom of the layer and the magnetization of the adjacent layers. For layers in which the NPs are more free to rotate, the easy axis of the NP can readily orient along the field direction. In more dense packing, free rotation of the NPs is hampered, and the NP ensembles likely build up quasi-domain states to minimize energy, which leads to lower magnetization in those layers. Detailed analysis of polarized neutron reflectometry data together with model calculations of the arrangement of the NPs within the layers and input from small-angle scattering measurements provide full characterization of the core/shell NP dimensions, degree of chaining, arrangement of the NPs within the different layers, and magnetization depth profile.

Airway Protective Mechanisms

PubMed Central

Pitts, Teresa

2014-01-01

Cough and swallow are highly coordinated reflex behaviors whose common purpose is to protect the airway. The pharynx is the common tube for air and food/liquid movement from the mouth into the thorax, has been largely overlooked, and is potentially seen as just a passive space. The thyropharyngeus muscle responds to cough inducing stimuli to prepare a transient holding area for material that has been removed from the subglottic airway. The cricopharyngeus muscle participates with the larynx to ensure regulation of pressure when a bolus/air is moving from the upper airway through to the thorax (i.e inspiration or swallow) or the reverse (i.e expiration reflex or vomiting).These vital mechanisms have not been evaluated in clinical conditions, but could be impaired in many neurodegenerative diseases leading to aspiration pneumonia. These newly described airway protective mechanisms need further study, especially in healthy and pathologic human populations. PMID:24297325

Air Entrainment and Surface Ripples in a Turbulent Ship Hull Boundary Layer

NASA Astrophysics Data System (ADS)

Masnadi, Naeem; Erinin, Martin; Duncan, James H.

2017-11-01

The air entrainment and free-surface fluctuations caused by the interaction of a free surface and the turbulent boundary layer of a vertical surface-piercing plate is studied experimentally. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes. This belt device is mounted inside a large water tank with the water level set just below the top edge of the belt. The belt, rollers, and supporting frame are contained within a sheet metal box to keep the device dry except for one 6-meter-long straight test section. The belt is accelerated suddenly from rest until reaching constant speed in order to create a temporally evolving boundary layer analogous to the spatially evolving boundary layer that would exist along a surface-piercing towed flat plate. Surface ripples are measured using a cinematic laser-induced fluorescence technique with the laser sheet oriented parallel or normal to the belt surface. Air entrainment events and bubble motions are recorded from underneath the water surface using a stereo imaging system. Measurements of small bubbles, that tend to stay submerged for a longer time, are planned via a high-speed digital in-line holographic system. The support of the Office of Naval Research is gratefully acknowledged.

Single Layer Surface-Grafted PMMA as a Negative-Tone e-Beam Resist.

PubMed

Yamada, Hirotaka; Aydinoglu, Ferhat; Liu, Yaoze; Dey, Ripon K; Cui, Bo

2017-12-05

One of the important challenges in electron beam lithography is nanofabrication on nonflat or irregular surfaces. Although spin coating is the most popular technique for resist coating, it is not suitable for nonflat, irregular substrates because a uniform film cannot be achieved on those surfaces. Here, it is demonstrated that single layer surface-grafted PMMA can be used as a negative-tone e-beam resist, and it can be applied to nonflat, irregular surfaces as well as flat, conventional surfaces. Although it is well known that heavily exposed PMMA undergoes cross-linking and works as a negative-tone e-beam resist when developed by solvent, solvent does not work as a developer for negative-tone single-layer surface-grafted PMMA. Instead, thermal treatment at 360 °C for 1 min is used to develop PMMA.

The effect of body weight on distal airway function and airway inflammation.

PubMed

van de Kant, Kim D G; Paredi, Paolo; Meah, Sally; Kalsi, Harpal S; Barnes, Peter J; Usmani, Omar S

Obesity is a global health problem that adversely influences the respiratory system. We assessed the effects of body mass index (BMI) on distal airway function and airway inflammation. Impulse oscillometry (IOS) as a measure of distal airway function, together with spirometry, were assessed in adults with a range of different BMIs. Airway inflammation was assessed with the fraction of exhaled nitric oxide (FeNO) and participants exhaled at various exhalation flows to determine alveolar and bronchial NO. In total 34 subjects were enrolled in the study; 19 subjects had a normal BMI (18.50-24.99), whilst 15 subjects were overweight (BMI 25.00-29.99), or obese (BMI ≥30). All subjects had normal spirometry. However, IOS measures of airway resistance (R) at 5Hz, 20Hz and frequency dependence (R 5-20 ) were elevated in overweight/obese individuals, compared to subjects with a normal BMI (median (interquartile range)); 5Hz: 0.41 (0.37, 0.45) vs. 0.32 (0.30, 0.37)kPa/l/s; 20Hz: 0.34 (0.30, 0.37) vs. 0.30 (0.26, 0.33)kPa/l/s; R 5-20 : 0.06 (0.04, 0.11) vs. 0.03 (0.01, 0.05)kPa/l/s; p<0.05), whereas airway reactance at 20Hz was decreased in overweight/obese individuals (20Hz: 0.07 (0.03, 0.09) vs. 0.10 (0.07, 0.13)kPa/l/s, p=0.009; 5Hz: -0.12 (-0.15, -0.10) vs. -0.10 (-0.13, -0.09)kPa/l/s, p=0.07). In contrast, within-breath IOS measures (a sign of expiratory flow limitation) and FeNO inflammatory measures, did not differ between groups (p>0.05). Being overweight has significant effects on distal and central airway function as determined by IOS, which is not detected by spirometry. Obesity does not influence airway inflammation as measured by FeNO. IOS is a reliable technique to identify airway abnormalities in the presence of normal spirometry in overweight people. Copyright © 2015 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

Surface Modification of Dental Titanium Implant by Layer-by-Layer Electrostatic Self-Assembly

PubMed Central

Shi, Quan; Qian, Zhiyong; Liu, Donghua; Liu, Hongchen

2017-01-01

In vivo implants that are composed of titanium and titanium alloys as raw materials are widely used in the fields of biology and medicine. In the field of dental medicine, titanium is considered to be an ideal dental implant material. Good osseointegration and soft tissue closure are the foundation for the success of dental implants. Therefore, the enhancement of the osseointegration and antibacterial abilities of titanium and its alloys has been the focus of much research. With its many advantages, layer-by-layer (LbL) assembly is a self-assembly technique that is used to develop multilayer films based on complementary interactions between differently charged polyelectrolytes. The LbL approach provides new methods and applications for the surface modification of dental titanium implant. In this review, the application of the LbL technique to surface modification of titanium including promoting osteogenesis and osseointegration, promoting the formation and healing of soft tissues, improving the antibacterial properties of titanium implant, achieving local drug delivery and sustained release is summarized. PMID:28824462

On the sensitivity of mesoscale models to surface-layer parameterization constants

NASA Astrophysics Data System (ADS)

Garratt, J. R.; Pielke, R. A.

1989-09-01

The Colorado State University standard mesoscale model is used to evaluate the sensitivity of one-dimensional (1D) and two-dimensional (2D) fields to differences in surface-layer parameterization “constants”. Such differences reflect the range in the published values of the von Karman constant, Monin-Obukhov stability functions and the temperature roughness length at the surface. The sensitivity of 1D boundary-layer structure, and 2D sea-breeze intensity, is generally less than that found in published comparisons related to turbulence closure schemes generally.

Thickness-dependent surface energies of few-layered arsenene and antimonene films in α and β phases

NASA Astrophysics Data System (ADS)

Zhao, N.; Zhu, Y. F.; Jiang, Q.

2018-07-01

Group V elemental few-layered materials with semiconducting electronic properties are emerging as promising 2D layered materials. Since the layered configurations need substrate for device fabrications, their surface energy values could decide their properties. Here, we have performed a systematic density functional theory (DFT) investigation on the surface energies of arsenene and antimonene films as the function of thickness. The results show that the surface energy of β phase increases with increased layered numbers and converges to a constant value at about five layers, while the surface energy of α phase is size-independent. Since the surface energies of both α and β phase are similar, there is the existence possibility of α phase. Those could give references for future manufacture of arsenene and antimonene nano-devices.

Experimental visualization of the cathode layer in AC surface dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Kim, Sang-You; Lho, Taihyeop; Chung, Kyu-Sun

2018-06-01

A narrow etched polyimide line at the bottom edge of a biased electrode (BE) and a non-etched dielectric surface near the biased electrode were observed in an atmospheric AC flexible surface dielectric barrier discharge of polyimide dielectric. These findings are attributed to the bombardment of positive oxygen ions on the bottom edge of the BE and the electron breakdown trajectory not contacting the polyimide surface following the electric field lines formed between the BE edge and the surface charge layer on the dielectric. The length of the non-etched dielectric surface during the first micro-discharge was observed as 22 μm. This occurred, regardless of three different operating durations, which is in good agreement with the length of the cathode layer according to Paschen's law.

Experimental and Computational Studies of Sound Transmission in a Branching Airway Network Embedded in a Compliant Viscoelastic Medium

PubMed Central

Dai, Zoujun; Peng, Ying; Mansy, Hansen A.; Sandler, Richard H.; Royston, Thomas J.

2015-01-01

Breath sounds are often used to aid in the diagnosis of pulmonary disease. Mechanical and numerical models could be used to enhance our understanding of relevant sound transmission phenomena. Sound transmission in an airway mimicking phantom was investigated using a mechanical model with a branching airway network embedded in a compliant viscoelastic medium. The Horsfield self-consistent model for the bronchial tree was adopted to topologically couple the individual airway segments into the branching airway network. The acoustics of the bifurcating airway segments were measured by microphones and calculated analytically. Airway phantom surface motion was measured using scanning laser Doppler vibrometry. Finite element simulations of sound transmission in the airway phantom were performed. Good agreement was achieved between experiments and simulations. The validated computational approach can provide insight into sound transmission simulations in real lungs. PMID:26097256

Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma patients.

PubMed

Hernandez, Matthew C; Aho, Johnathon M; Zielinski, Martin D; Zietlow, Scott P; Kim, Brian D; Morris, David S

2018-01-01

Prehospital airway management increasingly involves supraglottic airway insertion and a paucity of data evaluates outcomes in trauma populations. We aim to describe definitive airway management in traumatically injured patients who necessitated prehospital supraglottic airway insertion. We performed a single institution retrospective review of multisystem injured patients (≥15years) that received prehospital supraglottic airway insertion during 2009 to 2016. Baseline demographics, number and type of: supraglottic airway insertion attempts, definitive airway and complications were recorded. Primary outcome was need for tracheostomy. Univariate and multivariable statistics were performed. 56 patients met inclusion criteria and were reviewed, 78% were male. Median age [IQR] was 36 [24-56] years. Injuries comprised blunt (94%), penetrating (4%) and burns (2%). Median ISS was 26 [22-41]. Median number of prehospital endotracheal intubation (PETI) attempts was 2 [1-3]. Definitive airway management included: (n=20, 36%, tracheostomy), (n=10, 18%, direct laryngoscopy), (n=6, 11%, bougie), (n=9, 15%, Glidescope), (n=11, 20%, bronchoscopic assistance). 24-hour mortality was 41%. Increasing number of PETI was associated with increasing facial injury. On regression, increasing cervical and facial injury patterns as well as number of PETI were associated with definitive airway control via surgical tracheostomy. After supraglottic airway insertion, operative or non-operative approaches can be utilized to obtain a definitive airway. Patients with increased craniofacial injuries have an increased risk for airway complications and need for tracheostomy. We used these factors to generate an evidence based algorithm that requires prospective validation. Level IV - Retrospective study. Retrospective single institution study. Copyright © 2017 Elsevier Inc. All rights reserved.

Airway compliance and dynamics explain the apparent discrepancy in length adaptation between intact airways and smooth muscle strips.

PubMed

Dowie, Jackson; Ansell, Thomas K; Noble, Peter B; Donovan, Graham M

2016-01-01

Length adaptation is a phenomenon observed in airway smooth muscle (ASM) wherein over time there is a shift in the length-tension curve. There is potential for length adaptation to play an important role in airway constriction and airway hyper-responsiveness in asthma. Recent results by Ansell et al., 2015 (JAP 2014 10.1152/japplphysiol.00724.2014) have cast doubt on this role by testing for length adaptation using an intact airway preparation, rather than strips of ASM. Using this technique they found no evidence for length adaptation in intact airways. Here we attempt to resolve this apparent discrepancy by constructing a minimal mathematical model of the intact airway, including ASM which follows the classic length-tension curve and undergoes length adaptation. This allows us to show that (1) no evidence of length adaptation should be expected in large, cartilaginous, intact airways; (2) even in highly compliant peripheral airways, or at more compliant regions of the pressure-volume curve of large airways, the effect of length adaptation would be modest and at best marginally detectable in intact airways; (3) the key parameters which control the appearance of length adaptation in intact airways are airway compliance and the relaxation timescale. The results of this mathematical simulation suggest that length adaptation observed at the level of the isolated ASM may not clearly manifest in the normal intact airway. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal characteristics of the lunar surface layer.

NASA Technical Reports Server (NTRS)

Cremers, C. J.; Birkebak, R. C.; White, J. E.

1972-01-01

The thermophysical properties of the fines from the Apollo 12 landing site have been determined as a function of their relevant parameters. These properties include the thermal conductivity, thermal diffusivity, directional reflectance and emittance. The density used was the same as that observed from the returned core-tube samples and so should be close to the true density of the surface layer at the Apollo 12 site. The measured properties are used to calculate the diurnal temperature variation of the moon's surface as well as for several depths below the surface. The maximum surface of 389 K is obtained at lunar noon while the minimum temperature of 86.1 K is obtained at sunrise. It is shown that the most significant effects on temperature, as compared with previous calculations, are caused by using the directional reflectance which controls the amount of solar energy absorption during the day in place of a constant hemispherical reflectance. The results are compared with previous analyses and remote measurements.

Surface photovoltage studies of p-type AlGaN layers after reactive-ion etching

NASA Astrophysics Data System (ADS)

McNamara, J. D.; Phumisithikul, K. L.; Baski, A. A.; Marini, J.; Shahedipour-Sandvik, F.; Das, S.; Reshchikov, M. A.

2016-10-01

The surface photovoltage (SPV) technique was used to study the surface and electrical properties of Mg-doped, p-type AlxGa1-xN (0.06 < x < 0.17) layers. SPV measurements reveal significant deviation from previous SPV studies on p-GaN:Mg thin films and from the predictions of a thermionic model for the SPV behavior. In particular, the SPV of the p-AlGaN:Mg layers exhibited slower-than-expected transients under ultraviolet illumination and delayed restoration to the initial dark value. The slow transients and delayed restorations can be attributed to a defective surface region which interferes with normal thermionic processes. The top 45 nm of the p-AlGaN:Mg layer was etched using a reactive-ion etch which caused the SPV behavior to be substantially different. From this study, it can be concluded that a defective, near-surface region is inhibiting the change in positive surface charge by allowing tunneling or hopping conductivity of holes from the bulk to the surface, or by the trapping of electrons traveling to the surface by a high concentration of defects in the near-surface region. Etching removes the defective layer and reveals a region of presumably higher quality, as evidenced by substantial changes in the SPV behavior.

Identification of extracellular surface-layer associated proteins in Lactobacillus acidophilus NCFM

PubMed Central

Johnson, Brant; Selle, Kurt; O’Flaherty, Sarah; Goh, Yong Jun

2013-01-01

Bacterial surface (S-) layers are crystalline arrays of self-assembling, proteinaceous subunits called S-layer proteins (Slps), with molecular masses ranging from 40 to 200 kDa. The S-layer-forming bacterium Lactobacillus acidophilus NCFM expresses three major Slps: SlpA (46 kDa), SlpB (47 kDa) and SlpX (51 kDa). SlpA has a demonstrated role in adhesion to Caco-2 intestinal epithelial cells in vitro, and has been shown to modulate dendritic cell (DC) and T-cell functionalities with murine DCs. In this study, a modification of a standard lithium chloride S-layer extraction revealed 37 proteins were solubilized from the S-layer wash fraction. Of these, 30 have predicted cleavage sites for secretion, 24 are predicted to be extracellular, six are lipid-anchored, three have N-terminal hydrophobic membrane spanning regions and four are intracellular, potentially moonlighting proteins. Some of these proteins, designated S-layer associated proteins (SLAPs), may be loosely associated with or embedded within the bacterial S-layer complex. Lba-1029, a putative SLAP gene, was deleted from the chromosome of L. acidophilus. Phenotypic characterization of the deletion mutant demonstrated that the SLAP LBA1029 contributes to a pro-inflammatory TNF-α response from murine DCs. This study identified extracellular proteins and putative SLAPs of L. acidophilus NCFM using LC-MS/MS. SLAPs appear to impart important surface display features and immunological properties to microbes that are coated by S-layers. PMID:24002751

Receptivity of the Boundary Layer to Vibrations of the Wing Surface

NASA Astrophysics Data System (ADS)

Bernots, Tomass; Ruban, Anatoly; Pryce, David; Laminar Flow Control UK Group Team

2014-11-01

In this work we study generation of Tollmien-Schlichting (T-S) waves in the boundary layer due to elastic vibrations of the wing surface. The flow is investigated based on the asymptotic analysis of the Navier-Stokes equations at large values of the Reynolds number. It is assumed that in the spectrum of the wing vibrations there is a harmonic which comes in resonance with the T-S wave on the lower branch of the stability curve. It was found that the vibrations of the wing surface produce pressure perturbations in the flow outside the boundary layer which can be calculated with the help of the piston theory. As the pressure perturbations penetrate into the boundary layer, a Stokes layer forms on the wing surface which appears to be influenced significantly by the compressibility of the flow, and is incapable of producing the T-S waves. The situation changes when the Stokes layer encounters an roughness; near which the flow is described using the triple-deck theory. The solution of the triple-deck problem can be found in an analytic form. Our main concern is with the flow behaviour downstream of the roughness and, in particular, with the amplitude of the generated Tollmien-Schlichting waves. This research was performed in the Laminar Flow Control Centre (LFC-UK) at Imperial College London. The centre is supported by EPSRC, Airbus UK and EADS Innovation Works.

The impact of conventional surface data upon VAS regression retrievals in the lower troposphere

NASA Technical Reports Server (NTRS)

Lee, T. H.; Chesters, D.; Mostek, A.

1983-01-01

Surface temperature and dewpoint reports are added to the infrared radiances from the VISSR Atmospheric Sounder (VAS) in order to improve the retrieval of temperature and moisture profiles in the lower troposphere. The conventional (airways) surface data are combined with the twelve VAS channels as additional predictors in a ridge regression retrieval scheme, with the aim of using all available data to make high resolution space-time interpolations of the radiosonde network. For one day of VAS observations, retrievals using only VAS radiances are compared with retrievals using VAS radiances plus surface data. Temperature retrieval accuracy evaluated at coincident radiosonde sites shows a significant impact within the boundary layer. Dewpoint retrieval accuracy shows a broader improvement within the lowest tropospheric layers. The most dramatic impact of surface data is observed in the improved relative spatial and temporal continuity of low-level fields retrieved over the Midwestern United States.

Critical Airway Team: A Retrospective Study of an Airway Response System in a Pediatric Hospital.

PubMed

Sterrett, Emily C; Myer, Charles M; Oehler, Jennifer; Das, Bobby; Kerrey, Benjamin T

2017-12-01

Objective Study the performance of a pediatric critical airway response team. Study Design Case series with chart review. Setting Freestanding academic children's hospital. Subjects and Methods A structured review of the electronic medical record was conducted for all activations of the critical airway team. Characteristics of the activations and patients are reported using descriptive statistics. Activation of the critical airway team occurred 196 times in 46 months (March 2012 to December 2015); complete data were available for 162 activations (83%). For 49 activations (30%), patients had diagnoses associated with difficult intubation; 45 (28%) had a history of difficult laryngoscopy. Results Activation occurred at least 4 times per month on average (vs 3 per month for hospital-wide codes). The most common reasons for team activation were anticipated difficult intubation (45%) or failed intubation attempt (20%). For 79% of activations, the team performed an airway procedure, most commonly direct laryngoscopy and tracheal intubation. Bronchoscopy was performed in 47% of activations. Surgical airway rescue was attempted 4 times. Cardiopulmonary resuscitation occurred in 41 activations (25%). Twenty-nine patients died during or following team activation (18%), including 10 deaths associated with the critical airway event. Conclusion Critical airway team activation occurred at least once per week on average. Direct laryngoscopy, tracheal intubation, and bronchoscopic procedures were performed frequently; surgical airway rescue was rare. Most patients had existing risk factors for difficult intubation. Given our rate of serious morbidity and mortality, primary prevention of critical airway events will be a focus of future efforts.

Self-surface charge exfoliation and electrostatically coordinated 2D hetero-layered hybrids

PubMed Central

Yang, Min-Quan; Xu, Yi-Jun; Lu, Wanheng; Zeng, Kaiyang; Zhu, Hai; Xu, Qing-Hua; Ho, Ghim Wei

2017-01-01

At present, the technological groundwork of atomically thin two-dimensional (2D) hetero-layered structures realized by successive thin film epitaxial growth is in principle constrained by lattice matching prerequisite as well as low yield and expensive production. Here, we artificially coordinate ultrathin 2D hetero-layered metal chalcogenides via a highly scalable self-surface charge exfoliation and electrostatic coupling approach. Specifically, bulk metal chalcogenides are spontaneously exfoliated into ultrathin layers in a surfactant/intercalator-free medium, followed by unconstrained electrostatic coupling with a dissimilar transition metal dichalcogenide, MoSe2, into scalable hetero-layered hybrids. Accordingly, surface and interfacial-dominated photocatalysis reactivity is used as an ideal testbed to verify the reliability of diverse 2D ultrathin hetero-layered materials that reveal high visible-light photoreactivity, efficient charge transfer and intimate contact interface for stable cycling and storage purposes. Such a synthetic approach renders independent thickness and composition control anticipated to advance the development of ‘design-and-build' 2D layered heterojunctions for large-scale exploration and applications. PMID:28146147

A 4-Week Model of House Dust Mite (HDM) Induced Allergic Airways Inflammation with Airway Remodeling.

PubMed

Woo, L N; Guo, W Y; Wang, X; Young, A; Salehi, S; Hin, A; Zhang, Y; Scott, J A; Chow, C W

2018-05-02

Animal models of allergic airways inflammation are useful tools in studying the pathogenesis of asthma and potential therapeutic interventions. The different allergic airways inflammation models available to date employ varying doses, frequency, duration and types of allergen, which lead to the development of different features of asthma; showing varying degrees of airways inflammation and hyper-responsiveness (AHR) and airways remodeling. Models that also exhibit airway remodeling, a key feature of asthma, in addition to AHR and airway inflammation typically require 5-12 weeks to develop. In this report, we describe a 4-week mouse model of house dust mite (HDM)-induced allergic airways inflammation, and compare the phenotypic features of two different doses of HDM exposures (10 µg and 25 µg) for 5 days/week with a well-characterized 8-week chronic HDM model. We found that 4 weeks of intranasal HDM (25 µg in 35 µl saline; 5 days/week) resulted in AHR, airway inflammation and airway remodeling that were comparable to the 8-week model. We conclude that this new 4-week HDM model is another useful tool in studies of human asthma that offers advantages of shorter duration for development and decreased costs when compared to other models that require longer durations of exposure (5-12 weeks) to develop.

Spatial distribution of airway wall displacements during breathing and bronchoconstriction measured by ultrasound elastography using finite element image registration.

PubMed

Harvey, Brian C; Lutchen, Kenneth R; Barbone, Paul E

2017-03-01

With every breath, the airways within the lungs are strained. This periodic stretching is thought to play an important role in determining airway caliber in health and disease. Particularly, deep breaths can mitigate excessive airway narrowing in healthy subjects, but this beneficial effect is absent in asthmatics, perhaps due to an inability to stretch the airway smooth muscle (ASM) embedded within an airway wall. The heterogeneous composition throughout an airway wall likely modulates the strain felt by the ASM but the magnitude of ASM strain is difficult to measure directly. In this study, we optimized a finite element image registration method to measure the spatial distribution of displacements and strains throughout an airway wall during pressure inflation within the physiological breathing range before and after induced narrowing with acetylcholine (ACh). The method was shown to be repeatable, and displacements estimated from different image sequences of the same deformation agreed to within 5.3μm (0.77%). We found the magnitude and spatial distribution of displacements were radially and longitudinally heterogeneous. The region in the middle layer of the airway experienced the largest radial strain due to a transmural pressure (Ptm) increase simulating tidal breathing and a deep inspiration (DI), while the region containing the ASM (i.e., closest to the lumen) strained least. During induced narrowing with ACh, we observed temporal longitudinal heterogeneity of the airway wall. After constriction, the displacements and strain are much smaller than the relaxed airway and the pattern of strains changed, suggesting the airway stiffened heterogeneously. Copyright © 2016 Elsevier B.V. All rights reserved.

Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete

PubMed Central

Liu, Jun; Qiu, Qiwen; Xing, Feng; Pan, Dong

2014-01-01

This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP) test and the scanning electron microscopy (SEM) images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days. PMID:28788677

Operative endoscopy of the airway

PubMed Central

Walters, Dustin M.

2016-01-01

Airway endoscopy has long been an important and useful tool in the management of thoracic diseases. As thoracic specialists have gained experience with both flexible and rigid bronchoscopic techniques, the technology has continued to evolve so that bronchoscopy is currently the foundation for diagnosis and treatment of many thoracic ailments. Airway endoscopy plays a significant role in the biopsy of tumors within the airways, mediastinum, and lung parenchyma. Endoscopic methods have been developed to treat benign and malignant airway stenoses and tracheomalacia. And more recently, techniques have been conceived to treat end-stage emphysema and prolonged air leaks in select patients. This review describes the abundant uses of airway endoscopy, as well as technical considerations and limitations of the current technologies. PMID:26981263

Electrical properties of surface and interface layers of the N- and In-polar undoped and Mg-doped InN layers grown by PA MBE

NASA Astrophysics Data System (ADS)

Komissarova, T. A.; Kampert, E.; Law, J.; Jmerik, V. N.; Paturi, P.; Wang, X.; Yoshikawa, A.; Ivanov, S. V.

2018-01-01

Electrical properties of N-polar undoped and Mg-doped InN layers and In-polar undoped InN layers grown by plasma-assisted molecular beam epitaxy (PA MBE) were studied. Transport parameters of the surface and interface layers were determined from the measurements of the Hall coefficient and resistivity as well as the Shubnikov-de Haas oscillations at magnetic fields up to 60 T. Contributions of the 2D surface, 3D near-interface, and 2D interface layers to the total conductivity of the InN films were defined and discussed to be dependent on InN surface polarity, Mg doping, and PA MBE growth conditions.

Investigation of Selective Laser Melting Surface Alloyed Aluminium Metal Matrix Dispersive Reinforced Layers

NASA Astrophysics Data System (ADS)

Kamburov, V. V.; Dimitrova, R. B.; Kandeva, M. K.; Sofronov, Y. P.

2018-01-01

The aim of the paper is to investigate the improvement of mechanical properties and in particular wear resistance of laser surface alloyed dispersive reinforced thin layers produced by selective laser melting (SLM) technology. The wear resistance investigation of aluminium matrix composite layers in the conditions of dry friction surface with abrasive particles and nanoindentation tests were carried out. The process parameters (as scan speed) and their impact on the wear resistant layers have been evaluated. The alloyed layers containing metalized SiC particles were studied by Optical and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray microanalysis (EDX). The obtained experimental results of the laser alloyed thin layers show significant development of their wear resistance and nanohardness due to the incorporated reinforced phase of electroless nickel coated SiC particles.

Insights on persistent airway infection by non-typeable Haemophilus influenzae in chronic obstructive pulmonary disease

PubMed Central

Ahearn, Christian P.; Gallo, Mary C.

2017-01-01

Abstract Non-typeable Haemophilus influenzae (NTHi) is the most common bacterial cause of infection of the lower airways in adults with chronic obstructive pulmonary disease (COPD). Infection of the COPD airways causes acute exacerbations, resulting in substantial morbidity and mortality. NTHi has evolved multiple mechanisms to establish infection in the hostile environment of the COPD airways, allowing the pathogen to persist in the airways for months to years. Persistent infection of the COPD airways contributes to chronic airway inflammation that increases symptoms and accelerates the progressive loss of pulmonary function, which is a hallmark of the disease. Persistence mechanisms of NTHi include the expression of multiple redundant adhesins that mediate binding to host cellular and extracellular matrix components. NTHi evades host immune recognition and clearance by invading host epithelial cells, forming biofilms, altering gene expression and displaying surface antigenic variation. NTHi also binds host serum factors that confer serum resistance. Here we discuss the burden of COPD and the role of NTHi infections in the course of the disease. We provide an overview of NTHi mechanisms of persistence that allow the pathogen to establish a niche in the hostile COPD airways. PMID:28449098

Some physicochemical properties of surface layer soils shelterbelts in agricultural landscape

NASA Astrophysics Data System (ADS)

Jaskulska, R.; Szajdak, L.

2009-04-01

Shelterbelts belong to very efficient biogeochemical barriers. They decrease the migration of chemical compounds between ecosystems. The investigations were carried out in the Chlapowski's Agroecological Park in Turew situated 40 km South-West of Poznań, Poland. This area is located on loamy soils, which contains 70% cultivated fields and 14% shelterbelts and small afforestations. The shelterbelts represent different ages and the content of plants as well as humus quantity in surface layer. The first one is 100-year-old shelterbelt, where predominant species is Crataegus monogyna Jacq., Quercus rober L., and Fraxinus excelsior (L.) and is characterized by a well-developed humus level. The other one is 14-year-old shelterbelt. It includes 13 species of trees and revealed a small amount of humus. The soil under both shelterbelts is mineral, grey-brown podzolic in surface layer compound from light loamy sands and weakly loamy sands. The soil samples were taken from surface layer (0-20 cm). pH 1N KCl, hydrolytic acidity, cation-exchange capacity, total proper area, total organic carbon and dissociation constants were determined in soils. The study showed that the soil under shelterbelts revealed acidic properties. It was observed that soils of 100-year-old shelterbelt characterizing lowest values pH = 4.2 revealed highest values of hydrolytic acidity equaled to 7.8 cmol(+)ṡkg-1. The physicochemical properties of investigated soils shoved specific surface areas (22.8 m2ṡg-1), cationic sorptive capacity (12.9 cmol(+)ṡkg-1). TOC (1.6%) 100-year-old shelterbelt was higher than in 14-year-old shelterbelt. The dissociation constants were determined by potentiometric titration. This investigation revealed that the pK value was the highest in the humus of 100-year-old shelterbelt (pKa = 3.1). However, soils of 14-year-old shelterbelt characterized by the lovest pK equaled to 2.8. The surface layer soils shelterbelts in agricultural landscape with good humus development

Endogenous gamma-aminobutyric acid modulates tonic guinea pig airway tone and propofol-induced airway smooth muscle relaxation.

PubMed

Gallos, George; Gleason, Neil R; Virag, Laszlo; Zhang, Yi; Mizuta, Kentaro; Whittington, Robert A; Emala, Charles W

2009-04-01

Emerging evidence indicates that an endogenous autocrine/paracrine system involving gamma-aminobutyric acid (GABA) is present in airways. GABAA channels, GABAB receptors, and the enzyme that synthesizes GABA have been identified in airway epithelium and smooth muscle. However, the endogenous ligand itself, GABA, has not been measured in airway tissues. The authors sought to demonstrate that GABA is released in response to contractile agonists and tonically contributes a prorelaxant component to contracted airway smooth muscle. The amount and cellular localization of GABA in upper guinea pig airways under resting and contracted tone was determined by high pressure liquid chromatography and immunohistochemistry, respectively. The contribution that endogenous GABA imparts on the maintenance of airway smooth muscle acetylcholine-induced contraction was assessed in intact guinea pig airway tracheal rings using selective GABAA antagonism (gabazine) under resting or acetylcholine-contracted conditions. The ability of an allosteric agent (propofol) to relax a substance P-induced relaxation in an endogenous GABA-dependent manner was assessed. GABA levels increased and localized to airway smooth muscle after contractile stimuli in guinea pig upper airways. Acetylcholine-contracted guinea pig tracheal rings exhibited an increase in contracted force upon addition of the GABAA antagonist gabazine that was subsequently reversed by the addition of the GABAA agonist muscimol. Propofol dose-dependently relaxed a substance P contraction that was blocked by gabazine. These studies demonstrate that GABA is endogenously present and increases after contractile stimuli in guinea pig upper airways and that endogenous GABA contributes a tonic prorelaxant component in the maintenance of airway smooth muscle tone.

Endogenous γ-aminobutyric Acid Modulates Tonic Guinea Pig Airway Tone and Propofol-induced Airway Smooth Muscle Relaxation

PubMed Central

Gallos, George; Gleason, Neil R.; Virag, Laszlo; Zhang, Yi; Mizuta, Kentauro; Whittington, Robert A.; Emala, Charles W.

2009-01-01

Background Emerging evidence indicates that an endogenous autocrine/paracrine system involving γ-aminobutyric acid (GABA) is present in airways. GABAA channels, GABAB receptors and the enzyme that synthesizes GABA have been identified in airway epithelium and smooth muscle. However, the endogenous ligand itself, GABA, has not been measured in airway tissues. We sought to demonstrate that GABA is released in response to contractile agonists and tonically contributes a pro-relaxant component to contracted airway smooth muscle. Methods The amount and cellular localization of GABA in upper guinea pig airways under resting and contracted tone was determined by high pressure liquid chromatography and immunohistochemistry, respectively. The contribution that endogenous GABA imparts on the maintenance of airway smooth muscle acetylcholine-induced contraction was assessed in intact guinea pig airway tracheal rings using selective GABAA antagonism (gabazine) under resting or acetylcholine-contracted conditions. The ability of an allosteric agent (propofol) to relax a substance P-induced relaxation in an endogenous GABA-dependent manner was assessed. Results GABA levels increased and localized to airway smooth muscle following contractile stimuli in guinea pig upper airways. Acetylcholine-contracted guinea pig tracheal rings exhibited an increase in contracted force upon addition of the GABAA antagonist gabazine which was subsequently reversed by the addition of the GABAA agonist muscimol. Propofol dose-dependently relaxed a substance P contraction that was blocked by gabazine. Conclusion These studies demonstrate that GABA is endogenously present and increases following contractile stimuli in guinea pig upper airways and that endogenous GABA contributes a tonic pro-relaxant component in the maintenance of airway smooth muscle tone. PMID:19322939

Neurokinin-1 receptor mediates stress-exacerbated allergic airway inflammation and airway hyperresponsiveness in mice.

PubMed

Joachim, Ricarda A; Sagach, Viktoriya; Quarcoo, David; Dinh, Q Thai; Arck, Petra C; Klapp, Burghard F

2004-01-01

A wealth of clinical observation has suggested that stress and asthma morbidity are associated. We have previously established a mouse model of stress-exacerbated allergic airway inflammation, which reflects major clinical findings. The aim of the current study was to investigate the role of the neurokinin- (NK-)1 receptor in the mediation of stress effects in allergic airway inflammation. BALB/c mice were systemically sensitized with ovalbumin (OVA) on assay days 1, 14, and 21 and repeatedly challenged with OVA aerosol on days 26 and 27. Sound stress was applied to the animals for 24 hours, starting with the first airway challenge. Additionally, one group of stressed and one group of nonstressed mice received the highly specific NK-1 receptor antagonist RP 67580. Bronchoalveolar lavage fluid was obtained, and cell numbers and differentiation were determined. Airway hyperreactivity was measured in vitro by electrical field stimulation of tracheal smooth-muscle elements. Application of stress in sensitized and challenged animals resulted in a significant increase in leukocyte number in the bronchoalveolar lavage fluid. Furthermore, stressed animals showed enhanced airway reactivity. The increase of inflammatory cells and airway reactivity was blocked by treatment of animals with the NK-1 receptor antagonist. These data indicate that the NK-1 receptor plays an important role in mediating stress effects in allergen-induced airway inflammation.

The Human Airway Epithelial Basal Cell Transcriptome

PubMed Central

Wang, Rui; Zwick, Rachel K.; Ferris, Barbara; Witover, Bradley; Salit, Jacqueline; Crystal, Ronald G.

2011-01-01

Background The human airway epithelium consists of 4 major cell types: ciliated, secretory, columnar and basal cells. During natural turnover and in response to injury, the airway basal cells function as stem/progenitor cells for the other airway cell types. The objective of this study is to better understand human airway epithelial basal cell biology by defining the gene expression signature of this cell population. Methodology/Principal Findings Bronchial brushing was used to obtain airway epithelium from healthy nonsmokers. Microarrays were used to assess the transcriptome of basal cells purified from the airway epithelium in comparison to the transcriptome of the differentiated airway epithelium. This analysis identified the “human airway basal cell signature” as 1,161 unique genes with >5-fold higher expression level in basal cells compared to differentiated epithelium. The basal cell signature was suppressed when the basal cells differentiated into a ciliated airway epithelium in vitro. The basal cell signature displayed overlap with genes expressed in basal-like cells from other human tissues and with that of murine airway basal cells. Consistent with self-modulation as well as signaling to other airway cell types, the human airway basal cell signature was characterized by genes encoding extracellular matrix components, growth factors and growth factor receptors, including genes related to the EGF and VEGF pathways. Interestingly, while the basal cell signature overlaps that of basal-like cells of other organs, the human airway basal cell signature has features not previously associated with this cell type, including a unique pattern of genes encoding extracellular matrix components, G protein-coupled receptors, neuroactive ligands and receptors, and ion channels. Conclusion/Significance The human airway epithelial basal cell signature identified in the present study provides novel insights into the molecular phenotype and biology of the stem

Optimal graph based segmentation using flow lines with application to airway wall segmentation.

PubMed

Petersen, Jens; Nielsen, Mads; Lo, Pechin; Saghir, Zaigham; Dirksen, Asger; de Bruijne, Marleen

2011-01-01

This paper introduces a novel optimal graph construction method that is applicable to multi-dimensional, multi-surface segmentation problems. Such problems are often solved by refining an initial coarse surface within the space given by graph columns. Conventional columns are not well suited for surfaces with high curvature or complex shapes but the proposed columns, based on properly generated flow lines, which are non-intersecting, guarantee solutions that do not self-intersect and are better able to handle such surfaces. The method is applied to segment human airway walls in computed tomography images. Comparison with manual annotations on 649 cross-sectional images from 15 different subjects shows significantly smaller contour distances and larger area of overlap than are obtained with recently published graph based methods. Airway abnormality measurements obtained with the method on 480 scan pairs from a lung cancer screening trial are reproducible and correlate significantly with lung function.

Analyzing surface features on icy satellites using a new two-layer analogue model

NASA Astrophysics Data System (ADS)

Morales, K. M.; Leonard, E. J.; Pappalardo, R. T.; Yin, A.

2017-12-01

The appearance of similar surface morphologies across many icy satellites suggests potentially unified formation mechanisms. Constraining the processes that shape the surfaces of these icy worlds is fundamental to understanding their rheology and thermal evolution—factors that have implications for potential habitability. Analogue models have proven useful for investigating and quantifying surface structure formation on Earth, but have only been sparsely applied to icy bodies. In this study, we employ an innovative two-layer analogue model that simulates a warm, ductile ice layer overlain by brittle surface ice on satellites such as Europa and Enceladus. The top, brittle layer is composed of fine-grained sand while the ductile, lower viscosity layer is made of putty. These materials were chosen because they scale up reasonably to the conditions on Europa and Enceladus. Using this analogue model, we investigate the role of the ductile layer in forming contractional structures (e.g. folds) that would compensate for the over-abundance of extensional features observed on icy satellites. We do this by simulating different compressional scenarios in the analogue model and analyzing whether the resulting features resemble those on icy bodies. If the resulting structures are similar, then the model can be used to quantify the deformation by calculating strain. These values can then be scaled up to Europa or Enceladus and used to quantity the observed surface morphologies and the amount of extensional strain accommodated by certain features. This presentation will focus on the resulting surface morphologies and the calculated strain values from several analogue experiments. The methods and findings from this work can then be expanded and used to study other icy bodies, such as Triton, Miranda, Ariel, and Pluto.

CWEX: Crop/wind-energy experiment: Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

USDA-ARS?s Scientific Manuscript database

Large wind turbines perturb mean and turbulent wind characteristics, which modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could create significant changes in surface fluxes of heat, momentum, moisture, and CO2 over hundreds ...

Crop/Wind-energy Experiment (CWEX): Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

USDA-ARS?s Scientific Manuscript database

Perturbations of mean and turbulent wind characteristics by large wind turbines modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could significantly change surface fluxes of heat, momentum, moisture, and CO2 over hundreds of s...

Three-dimensional airways reconstruction in syndromic pedriatric patients following mandibular distraction osteogenesis.

PubMed

Spinelli, Giuseppe; Agostini, Tommaso; Arcuri, Francesco; Conti, Marco; Raffaini, Mirco

2015-05-01

Airway obstruction, associated with mandibular hypoplasia, is a frequent complication in syndromic pediatric patients. The clinical signs of airway obstruction change from mild positional obstruction to severe respiratory distress with cyanosis. The young age of the patients makes medical management extremely complex. The purpose was to evaluate the success of surgery, evaluating the expansion of the respiratory volumes measured by computer tomography analyzed through a software (SimPlant Pro 15). Twelve patients with mandibular hypoplasia and respiratory distress were treated between December 2010 and December 2013. Eleven of them had tracheostomy in the preoperative period. The goal of surgery was to prevent permanent tracheostomy or to remove it, if present. Volume and surface area increased by an average of 279.2% and 89.4%, respectively. Tracheostomy was avoided in 1 patient who underwent surgery precociously, and it was removed in 10 patients. Only 1 case failed in volume airway augmentation, and tracheostomy was not removed. Computer tomography can calculate the cross-sectional areas of the airway in 3 planes of space: coronal, sagittal, and axial. In most patients, changes in airways have been accompanied by improvements in sleep and breathing, allowing for the removal of tracheostomy with an improved quality of life. Three-dimensional reconstruction of airways revealed a useful tool to better understand the success of surgery. IV.

Surface layer modification of ion bombarded HDPE

NASA Astrophysics Data System (ADS)

Bielinski, D.; Lipinski, P.; Slusarski, L.; Grams, J.; Paryjczak, T.; Jagielski, J.; Turos, A.; Madi, N. K.

2004-08-01

Press-moulded, high density polyethylene (HDPE) samples were subjected to ion bombardment and effects of the modification studied. He + ions of energy 100 keV or Ar + ions of energy 130 keV were applied in the range of dose 1-30 × 10 15/cm 2 or 1-100 × 10 14/cm 2, respectively. This paper has been focused on structural changes of the surface layer. The consequences of the modification were studied with TOF-SIMS and FTIR-IRS techniques. The results point on two mechanisms taking place simultaneously: ionization of polymer macromolecules and chain scission--resulting in creation of macroradicals. Both of them produce oxidation and lead to significant release of hydrogen. The former diminishes for the highest ion doses, however, creation of molecular oxygen cannot be excluded. The latter in the case of Ar + ion bombardment is reflected by prevailing degradation of the surface layer of HDPE. Contrary to the effect of heavy ions, He + ion bombardment was found to produce significant increase of the material hardness, which was explained by crosslinking of polyethylene. A mechanism of polyacetylene formation, proceeding finally to cross-polymerization of the polymer was proposed. Apart from structural changes, the modification revealed additionally a possibility to improve the wettability of the polymer.

NMR of thin layers using a meanderline surface coil

DOEpatents

Cowgill, Donald F.

2001-01-01

A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

Physical principle of airway design in human lungs

NASA Astrophysics Data System (ADS)

Park, Keunhwan; Son, Taeho; Kim, Wonjung; Kim, Ho-Young

2014-11-01

From an engineering perspective, lungs are natural microfluidic devices that extract oxygen from air. In the bronchial tree, airways branch by dichotomy with a systematic reduction of their diameters. It is generally accepted that in conducting airways, which air passes on the way to the acinar airways from the atmosphere, the reduction ratio of diameter is closely related to the minimization of viscous dissipation. Such a principle is formulated as the Hess-Murray law. However, in acinar airways, where oxygen transfer to alveolae occurs, the diameter reduction with progressive generations is more moderate than in conducting airways. Noting that the dominant transfer mechanism in acinar airways is diffusion rather than advection, unlike conducting airways, we construct a mathematical model for oxygen transfer through a series of acinar airways. Our model allows us to predict the optimal airway reduction ratio that maximizes the oxygen transfer in a finite airway volume, thereby rationalizing the observed airway reduction ratio in acinar airways.

Airway management in cervical spine injury

PubMed Central

Austin, Naola; Krishnamoorthy, Vijay; Dagal, Arman

2014-01-01

To minimize risk of spinal cord injury, airway management providers must understand the anatomic and functional relationship between the airway, cervical column, and spinal cord. Patients with known or suspected cervical spine injury may require emergent intubation for airway protection and ventilatory support or elective intubation for surgery with or without rigid neck stabilization (i.e., halo). To provide safe and efficient care in these patients, practitioners must identify high-risk patients, be comfortable with available methods of airway adjuncts, and know how airway maneuvers, neck stabilization, and positioning affect the cervical spine. This review discusses the risks and benefits of various airway management strategies as well as specific concerns that affect patients with known or suspected cervical spine injury. PMID:24741498

Relationships between equine airway reactivity measured by flowmetric plethysmography and specific indicators of airway inflammation in horses with suspected inflammatory airway disease.

PubMed

Wichtel, M; Gomez, D; Burton, S; Wichtel, J; Hoffman, A

2016-07-01

Agreement between airway reactivity measured by flowmetric plethysmography and histamine bronchoprovocation, and lower airway inflammation measured by bronchoalveolar lavage (BAL) cytology, has not been studied in horses with suspected inflammatory airway disease (IAD). We tested the hypothesis that airway reactivity is associated with BAL cytology in horses presenting for unexplained poor performance and/or chronic cough. Prospective clinical study. Forty-five horses, predominantly young Standardbred racehorses, presenting for unexplained poor performance or chronic cough, underwent endoscopic evaluation, tracheal wash, flowmetric plethysmography with histamine bronchoprovocation and BAL. Histamine response was measured by calculating PC35, the concentration of nebulised histamine eliciting an increase in Δflow of 35%. In this population, there was no significant correlation between histamine response and cell populations in BAL cytology. When airway hyperreactivity (AHR) was defined as ≥35% increase in Δflow at a histamine concentration of <6 mg/ml, 24 of the 45 horses (53%) were determined to have AHR. Thirty-three (73%) had either abnormal BAL cytology or AHR, and were diagnosed with IAD on this basis. Of horses diagnosed with IAD, 9 (27%) had an abnormal BAL, 11 (33%) had AHR and 13 (39%) had both. Airway reactivity and BAL cytology did not show concordance in this population of horses presenting for unexplained poor performance and/or chronic cough. Failure to include tests of airway reactivity may lead to underdiagnosis of IAD in young Standardbred racehorses that present with clinical signs suggestive of IAD. © 2015 EVJ Ltd.

Anatomic Optical Coherence Tomography of Upper Airways

NASA Astrophysics Data System (ADS)

Chin Loy, Anthony; Jing, Joseph; Zhang, Jun; Wang, Yong; Elghobashi, Said; Chen, Zhongping; Wong, Brian J. F.

The upper airway is a complex and intricate system responsible for respiration, phonation, and deglutition. Obstruction of the upper airways afflicts an estimated 12-18 million Americans. Pharyngeal size and shape are important factors in the pathogenesis of airway obstructions. In addition, nocturnal loss in pharyngeal muscular tone combined with high pharyngeal resistance can lead to collapse of the airway and periodic partial or complete upper airway obstruction. Anatomical optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images of the airway lumen without the use of ionizing radiation. In this chapter we describe the methods behind endoscopic OCT imaging and processing to generate full three dimensional anatomical models of the human airway which can be used in conjunction with numerical simulation methods to assess areas of airway obstruction. Combining this structural information with flow dynamic simulations, we can better estimate the site and causes of airway obstruction and better select and design surgery for patients with obstructive sleep apnea.

Radiology-guided forceps biopsy and airway stenting in severe airway stenosis.

PubMed

Li, Zong Ming; Wu, Gang; Han, Xin Wei; Ren, Ke Wei; Zhu, Ming

2014-01-01

We aimed to determine the feasibility, safety, and effectiveness of radiology-guided forceps biopsy and airway stenting in patients with severe airway stenosis. This study involved 28 patients with severe airway stenosis who underwent forceps biopsy between October 2006 and September 2011. Chest multislice computed tomography was used to determine the location and extent of stenosis. Sixteen patients had tracheal stenosis, two patients had stenosis of the tracheal carina, six patients had stenosis of the left main bronchus, and four patients had stenosis of the right main bronchus. Forceps biopsy and stenting of the stenosed area were performed under fluoroscopic guidance in digital subtraction angiography and the biopsy specimens were analyzed histopathologically. We contacted the patients via phone call and utilized a standardized questionnaire to determine their medical condition during a postoperative three-month follow-up. The technical success rate of radiology-guided forceps biopsy was 100%. Biopsy specimens were obtained in all patients. Dyspnea was relieved immediately after stent placement. No serious complications, such as tracheal hemorrhage or perforation, mediastinal emphysema, or asphyxia, occurred. Radiology-guided forceps biopsy and airway stenting can be used for the emergency treatment of severe airway stenosis. This method appears to be safe and effective, and it may be an alternative therapeutic option in patients who cannot tolerate fiberoptic bronchoscopy.

Radiology-guided forceps biopsy and airway stenting in severe airway stenosis

PubMed Central

Li, Zong-Ming; Wu, Gang; Han, Xin-Wei; Ren, Ke-Wei; Zhu, Ming

2014-01-01

PURPOSE We aimed to determine the feasibility, safety, and effectiveness of radiology-guided forceps biopsy and airway stenting in patients with severe airway stenosis. MATERIALS AND METHODS This study involved 28 patients with severe airway stenosis who underwent forceps biopsy between October 2006 and September 2011. Chest multislice computed tomography was used to determine the location and extent of stenosis. Sixteen patients had tracheal stenosis, two patients had stenosis of the tracheal carina, six patients had stenosis of the left main bronchus, and four patients had stenosis of the right main bronchus. Forceps biopsy and stenting of the stenosed area were performed under fluoroscopic guidance in digital subtraction angiography and the biopsy specimens were analyzed histopathologically. We contacted the patients via phone call and utilized a standardized questionnaire to determine their medical condition during a postoperative three-month follow-up. RESULTS The technical success rate of radiology-guided forceps biopsy was 100%. Biopsy specimens were obtained in all patients. Dyspnea was relieved immediately after stent placement. No serious complications, such as tracheal hemorrhage or perforation, mediastinal emphysema, or asphyxia, occurred. CONCLUSION Radiology-guided forceps biopsy and airway stenting can be used for the emergency treatment of severe airway stenosis. This method appears to be safe and effective, and it may be an alternative therapeutic option in patients who cannot tolerate fiberoptic bronchoscopy. PMID:24808434

Metal Surface Modification for Obtaining Nano- and Sub-Nanostructured Protective Layers.

PubMed

Ledovskykh, Volodymyr; Vyshnevska, Yuliya; Brazhnyk, Igor; Levchenko, Sergiy

2017-12-01

Regularities of the phase protective layer formation in multicomponent systems involving inhibitors with different mechanism of protective action have been investigated. It was shown that optimization of the composition of the inhibition mixture allows to obtain higher protective efficiency owing to improved microstructure of the phase layer. It was found that mechanism of the film formation in the presence of NaNO 2 -PHMG is due to deposition of slightly soluble PHMG-Fe complexes on the metal surface. On the basis of the proposed mechanism, the advanced surface engineering methods for obtaining nanoscaled and sub-nanostructured functional coatings may be developed.

Metal Surface Modification for Obtaining Nano- and Sub-Nanostructured Protective Layers

NASA Astrophysics Data System (ADS)

Ledovskykh, Volodymyr; Vyshnevska, Yuliya; Brazhnyk, Igor; Levchenko, Sergiy

2017-03-01

Regularities of the phase protective layer formation in multicomponent systems involving inhibitors with different mechanism of protective action have been investigated. It was shown that optimization of the composition of the inhibition mixture allows to obtain higher protective efficiency owing to improved microstructure of the phase layer. It was found that mechanism of the film formation in the presence of NaNO2-PHMG is due to deposition of slightly soluble PHMG-Fe complexes on the metal surface. On the basis of the proposed mechanism, the advanced surface engineering methods for obtaining nanoscaled and sub-nanostructured functional coatings may be developed.

Effect of inversion layer at iron pyrite surface on photovoltaic device

NASA Astrophysics Data System (ADS)

Uchiyama, Shunsuke; Ishikawa, Yasuaki; Uraoka, Yukiharu

2018-03-01

Iron pyrite has great potential as a thin-film solar cell material because it has high optical absorption, low cost, and is earth-abundant. However, previously reported iron pyrite solar cells showed poor photovoltaic characteristics. Here, we have numerically simulated its photovoltaic characteristics and band structures by utilizing a two-dimensional (2D) device simulator, ATLAS, to evaluate the effects of an inversion layer at the surface and a high density of deep donor defect states in the bulk. We found that previous device structures did not consider the inversion layer at the surface region of iron pyrite, which made it difficult to obtain the conversion efficiency. Therefore, we remodeled the device structure and suggested that removing the inversion layer and reducing the density of deep donor defect states would lead to a high conversion efficiency of iron pyrite solar cells.

Method for producing functionally graded nanocrystalline layer on metal surface

DOEpatents

Ajayi, Oyelayo O.; Hershberger, Jeffrey G.

2010-03-23

An improved process for the creation or formation of nanocrystalline layers on substrates' surfaces is provided. The process involves "prescuffing" the surface of a substrate such as a metal by allowing friction to occur on the surface by a load-bearing entity making rubbing contact and moving along and on the substrate's surface. The "prescuffing" action is terminated when the coefficient of friction between the surface and the noise is rising significantly. Often, the significant rise in the coefficient of friction is signaled by a change in pitch of the scuffing action sound emanating from the buffeted surface. The "prescuffing" gives rise to a harder and smoother surface which withstands better any inadequate lubrication that may take place when the "prescuffed" surface is contacted by other surfaces.

Changes of electrical conductivity of the metal surface layer by the laser alloying with foreign elements

NASA Astrophysics Data System (ADS)

Kostrubiec, Franciszek; Pawlak, Ryszard; Raczynski, Tomasz; Walczak, Maria

1994-09-01

Laser treatment of the surface of materials is of major importance for many fields technology. One of the latest and most significant methods of this treatment is laser alloying consisting of introducing foreign atoms into the metal surface layer during the reaction of laser radiation with the surface. This opens up vast possibilities for the modification of properties of such a layer (obtaining layers of increased microhardness, increased resistance to electroerosion in an electric arc, etc.). Conductivity of the material is a very important parameter in case of conductive materials used for electrical contacts. The paper presents the results of studies on change in electrical conductivity of the surface layer of metals alloyed with a laser. A comparative analysis of conductivity of base metal surface layers prior to and following laser treatment has been performed. Depending on the base metal and the alloying element, optical treatment parameters allowing a required change in the surface layer conductivity have been selected. A very important property of the contact material is its resistance to plastic strain. It affects the real value of contact surface coming into contact and, along with the material conductivity, determines contact resistance and the amount of heat generated in place of contact. These quantities are directly related to the initiation and the course of an arc discharge, hence they also affect resistance to electroerosion. The parameter that reflects plastic properties with loads concentrated on a small surface, as is the case with a reciprocal contact force of two real surfaces with their irregularities being in contact, is microhardness. In the paper, the results of investigations into microhardness of modified surface layers compared with base metal microhardness have been presented.

An Optimal Estimation Method to Obtain Surface Layer Turbulent Fluxes from Profile Measurements

NASA Astrophysics Data System (ADS)

Kang, D.

2015-12-01

In the absence of direct turbulence measurements, the turbulence characteristics of the atmospheric surface layer are often derived from measurements of the surface layer mean properties based on Monin-Obukhov Similarity Theory (MOST). This approach requires two levels of the ensemble mean wind, temperature, and water vapor, from which the fluxes of momentum, sensible heat, and water vapor can be obtained. When only one measurement level is available, the roughness heights and the assumed properties of the corresponding variables at the respective roughness heights are used. In practice, the temporal mean with large number of samples are used in place of the ensemble mean. However, in many situations the samples of data are taken from multiple levels. It is thus desirable to derive the boundary layer flux properties using all measurements. In this study, we used an optimal estimation approach to derive surface layer properties based on all available measurements. This approach assumes that the samples are taken from a population whose ensemble mean profile follows the MOST. An optimized estimate is obtained when the results yield a minimum cost function defined as a weighted summation of all error variance at each sample altitude. The weights are based one sample data variance and the altitude of the measurements. This method was applied to measurements in the marine atmospheric surface layer from a small boat using radiosonde on a tethered balloon where temperature and relative humidity profiles in the lowest 50 m were made repeatedly in about 30 minutes. We will present the resultant fluxes and the derived MOST mean profiles using different sets of measurements. The advantage of this method over the 'traditional' methods will be illustrated. Some limitations of this optimization method will also be discussed. Its application to quantify the effects of marine surface layer environment on radar and communication signal propagation will be shown as well.

An ocean large-eddy simulation of Langmuir circulations and convection in the surface mixed layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skyllingstad, E.D.; Denbo, D.W.

Numerical experiments were performed using a three-dimensional large-eddy simulation model of the ocean surface mixed layer that includes the Craik-Leibovich vortex force to parameterize the interaction of surface waves with mean currents. Results from the experiments show that the vortex force generates Langmuir circulations that can dominate vertical mixing. The simulated vertical velocity fields show linear, small-scale, coherent structures near the surface that extend downwind across the model domain. In the interior of the mixed layer, scales of motion increase to eddy sizes that are roughly equivalent to the mixed-layer depth. Cases with the vortex force have stronger circulations nearmore » the surface in contrast to cases with only heat flux and wind stress, particularly when the heat flux is positive. Calculations of the velocity variance and turbulence dissipation rates for cases with and without the vortex force, surface cooling, and wind stress indicate that wave-current interactions are a dominant mixing process in the upper mixed layer. Heat flux calculations show that the entrainment rate at the mixed-layer base can be up to two times greater when the vortex force is included. In a case with reduced wind stress, turbulence dissipation rates remained high near the surface because of the vortex force interaction with preexisting inertial currents. In deep mixed layers ({approximately}250 m) the simulations show that Langmuir circulations can vertically transport water 145 m during conditions of surface heating. Observations of turbulence dissipation rates and the vertical temperature structure support the model results. 42 refs., 20 figs., 21 tabs.« less

Shear-induced surface alignment of polymer dispersed liquid crystal microdroplets on the boundary layer

NASA Technical Reports Server (NTRS)

Parmar, D. S.; Singh, J. J.

1993-01-01

Polymer dispersed liquid crystal thin films have been deposited on a glass substrate, utilizing the processes of polymerization and solvent evaporation induced phase separation. Liquid crystal microdroplets trapped on the upper surface of the thin film respond to the shear stress due to air or gas flow on the surface layer. Response to an applied step shear stress input on the surface layer has been measured by measuring the time response of the transmitted light intensity. Initial results on the measurements of the light transmission as a function of the air flow differential pressure indicate that these systems offer features suitable for boundary layer and gas flow sensors.

Creation of deuterium protective layer below the tungsten surface

NASA Astrophysics Data System (ADS)

Krstic, Predrag; Kaganovich, Igor; Startsev, Edward

2014-10-01

By cumulative irradiation of both pre-damaged and virgin surfaces of monocrystal tungsten by deuterium atoms of impact energy of few tens of eV, we simulate by classical molecular dynamics the creation of a deuterium protective layer. The depth and width of the layer depend on the deuterium impact energy and the diffusion rate of deuterium in tungsten, the latter being influenced by the tungsten temperature and damage. Found simulation results are in concert with the experimental results, found recently in DIFFER. Support of the PPPL LDRD project acknowledged.

Interaction of Mycobacterium leprae with Human Airway Epithelial Cells: Adherence, Entry, Survival, and Identification of Potential Adhesins by Surface Proteome Analysis

PubMed Central

Silva, Carlos A. M.; Danelishvili, Lia; McNamara, Michael; Berredo-Pinho, Márcia; Bildfell, Robert; Biet, Franck; Rodrigues, Luciana S.; Oliveira, Albanita V.

2013-01-01

This study examined the in vitro interaction between Mycobacterium leprae, the causative agent of leprosy, and human alveolar and nasal epithelial cells, demonstrating that M. leprae can enter both cell types and that both are capable of sustaining bacterial survival. Moreover, delivery of M. leprae to the nasal septum of mice resulted in macrophage and epithelial cell infection in the lung tissue, sustaining the idea that the airways constitute an important M. leprae entry route into the human body. Since critical aspects in understanding the mechanisms of infection are the identification and characterization of the adhesins involved in pathogen-host cell interaction, the nude mouse-derived M. leprae cell surface-exposed proteome was studied to uncover potentially relevant adhesin candidates. A total of 279 cell surface-exposed proteins were identified based on selective biotinylation, streptavidin-affinity purification, and shotgun mass spectrometry; 11 of those proteins have been previously described as potential adhesins. In vitro assays with the recombinant forms of the histone-like protein (Hlp) and the heparin-binding hemagglutinin (HBHA), considered to be major mycobacterial adhesins, confirmed their capacity to promote bacterial attachment to epithelial cells. Taking our data together, they suggest that the airway epithelium may act as a reservoir and/or portal of entry for M. leprae in humans. Moreover, our report sheds light on the potentially critical adhesins involved in M. leprae-epithelial cell interaction that may be useful in designing more effective tools for leprosy control. PMID:23670556

Interaction of Mycobacterium leprae with human airway epithelial cells: adherence, entry, survival, and identification of potential adhesins by surface proteome analysis.

PubMed

Silva, Carlos A M; Danelishvili, Lia; McNamara, Michael; Berredo-Pinho, Márcia; Bildfell, Robert; Biet, Franck; Rodrigues, Luciana S; Oliveira, Albanita V; Bermudez, Luiz E; Pessolani, Maria C V

2013-07-01

This study examined the in vitro interaction between Mycobacterium leprae, the causative agent of leprosy, and human alveolar and nasal epithelial cells, demonstrating that M. leprae can enter both cell types and that both are capable of sustaining bacterial survival. Moreover, delivery of M. leprae to the nasal septum of mice resulted in macrophage and epithelial cell infection in the lung tissue, sustaining the idea that the airways constitute an important M. leprae entry route into the human body. Since critical aspects in understanding the mechanisms of infection are the identification and characterization of the adhesins involved in pathogen-host cell interaction, the nude mouse-derived M. leprae cell surface-exposed proteome was studied to uncover potentially relevant adhesin candidates. A total of 279 cell surface-exposed proteins were identified based on selective biotinylation, streptavidin-affinity purification, and shotgun mass spectrometry; 11 of those proteins have been previously described as potential adhesins. In vitro assays with the recombinant forms of the histone-like protein (Hlp) and the heparin-binding hemagglutinin (HBHA), considered to be major mycobacterial adhesins, confirmed their capacity to promote bacterial attachment to epithelial cells. Taking our data together, they suggest that the airway epithelium may act as a reservoir and/or portal of entry for M. leprae in humans. Moreover, our report sheds light on the potentially critical adhesins involved in M. leprae-epithelial cell interaction that may be useful in designing more effective tools for leprosy control.

Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength.

PubMed

Bijelic-Donova, Jasmina; Garoushi, Sufyan; Lassila, Lippo V J; Vallittu, Pekka K

2015-02-01

An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short-fiber-reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical-shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000-grit silicon-carbide (SiC) abrasive paper, or treatment with ethanol or with water-spray. The inhibition depth was lowest (11.6 μm) for water-sprayed Silorane and greatest (22.9 μm) for the water-sprayed short-fiber-reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water-sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite. Thus, more durable adhesion with short-fiber-reinforced composite is expected. © 2014 Eur J Oral Sci.

Inflammatory bowel disease and airway diseases.

PubMed

Vutcovici, Maria; Brassard, Paul; Bitton, Alain

2016-09-14

Airway diseases are the most commonly described lung manifestations of inflammatory bowel disease (IBD). However, the similarities in disease pathogenesis and the sharing of important environmental risk factors and genetic susceptibility suggest that there is a complex interplay between IBD and airway diseases. Recent evidence of IBD occurrence among patients with airway diseases and the higher than estimated prevalence of subclinical airway injuries among IBD patients support the hypothesis of a two-way association. Future research efforts should be directed toward further exploration of this association, as airway diseases are highly prevalent conditions with a substantial public health impact.

Administration of SIN-1 induces guinea pig airway hyperresponsiveness through inactivation of airway neutral endopeptidase.

PubMed

Kanazawa, H; Hirata, K; Yoshikawa, J

1999-12-01

Peroxynitrite plays an important role in the pathogenesis of airway inflammation. We have already found that peroxynitrite may contribute to decreased beta(2)-adrenoceptor responses in airway smooth muscle. However, it is not known whether peroxynitrite can alter neutral endopeptidase (EC 3.4.24.11; NEP) activity in the airways. This study was designed to determine whether peroxynitrite induces airway hyperresponsiveness to substance P (SP) and endothelin-1 (ET-1) through the inactivation of airway NEP. We examined whether the administration of S-morpholinosydnonimine (SIN-1), a compound that releases peroxynitrite, increased bronchoconstrictor responses to SP and ET-1 in anesthetized guinea pigs. In addition, we assayed NEP activity in the airways of SIN-1-exposed guinea pigs. Though SIN-1 (10(-7) M) alone had no effect on pulmonary resistance, pretreatment with SIN-1 significantly enhanced SP- and ET-1-induced bronchoconstriction. Pretreatment with phosphoramidon, an NEP inhibitor, also enhanced SP- and ET-1-induced bronchoconstriction. However, simultaneous administration of phosphoramidon and SIN-1 had no additive effect on SP- and ET-1-induced bronchoconstriction. Peroxynitrite formation by SIN-1 was completely inhibited by N-acetylcysteine (NAC) and glutathione (GSH) in vitro, and pretreatment with NAC and GSH significantly reversed the potentiation by SIN-1 of SP-induced bronchoconstriction. In addition, the NEP activity of the trachea after SIN-1 exposure was significantly reduced compared to the level in control guinea pigs (solvent for SIN-1: 30.0+/-4.2 fmol.min(-1).mg tissue(-1); 10(-7) M SIN-1; 15.5+/-4.5 fmol.min(-1).mg tissue(-1), p<0.05). These findings suggest that peroxynitrite induces airway hyperresponsiveness to SP and ET-1 through the inactivation of airway NEP, and that peroxynitrite is an important mediator of the alterations in airway functions.

Influence of substrate preparation on the shaping of the topography of the surface of nanoceramic oxide layers

NASA Astrophysics Data System (ADS)

Bara, Marek; Kubica, Marek

2014-02-01

The paper discusses the shaping mechanism and changes occurring in the structure and topography of the surface of nanoceramic oxide layers during their formation. The paper presents the influence of substrate preparation on the surface topography of oxide layers. The layers were produced via hard anodizing on the EN AW-5251 aluminum alloy. The layers obtained were subjected to microscope examinations, image and chemical composition analyses, and stereometric examinations. Heredity of substrate properties in the topography of the surface of nanoceramic oxide layers formed as a result of electrochemical oxidation has been shown.

RAGE: a new frontier in chronic airways disease

PubMed Central

Sukkar, Maria B; Ullah, Md Ashik; Gan, Wan Jun; Wark, Peter AB; Chung, Kian Fan; Hughes, J Margaret; Armour, Carol L; Phipps, Simon

2012-01-01

Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous inflammatory disorders of the respiratory tract characterized by airflow obstruction. It is now clear that the environmental factors that drive airway pathology in asthma and COPD, including allergens, viruses, ozone and cigarette smoke, activate innate immune receptors known as pattern-recognition receptors, either directly or indirectly by causing the release of endogenous ligands. Thus, there is now intense research activity focused around understanding the mechanisms by which pattern-recognition receptors sustain the airway inflammatory response, and how these mechanisms might be targeted therapeutically. One pattern-recognition receptor that has recently come to attention in chronic airways disease is the receptor for advanced glycation end products (RAGE). RAGE is a member of the immunoglobulin superfamily of cell surface receptors that recognizes pathogen- and host-derived endogenous ligands to initiate the immune response to tissue injury, infection and inflammation. Although the role of RAGE in lung physiology and pathophysiology is not well understood, recent genome-wide association studies have linked RAGE gene polymorphisms with airflow obstruction. In addition, accumulating data from animal and clinical investigations reveal increased expression of RAGE and its ligands, together with reduced expression of soluble RAGE, an endogenous inhibitor of RAGE signalling, in chronic airways disease. In this review, we discuss recent studies of the ligand–RAGE axis in asthma and COPD, highlight important areas for future research and discuss how this axis might potentially be harnessed for therapeutic benefit in these conditions. PMID:22506507

Airway extravasation induced by increasing airway temperature in ovalbumin-sensitized rats

PubMed Central

Hsu, Chun-Chun; Tapia, Reyno J.; Lee, Lu-Yuan

2015-01-01

This study was carried out to determine whether hyperventilation of humidified warm air (HWA) induced airway extravasation in ovalbumin (Ova)-sensitized rats. Our results showed: 1) After isocapnic hyperventilation with HWA for 2 min, tracheal temperature (Ttr) was increased to 40.3°C, and the Evans blue contents in major airways and lung tissue were elevated to 651% and 707%, respectively, of that after hyperventilation with humidified room air in Ova-sensitized rats; this striking effect of HWA was absent in control rats. 2) The HWA-induced increase in Evans blue content in sensitized rats was completely prevented by a pretreatment with either L-732138, a selective antagonist of neurokinin type 1 (NK-1) receptor, or formoterol, a selective agonist of β2 adrenoceptor. This study demonstrated that an increase in airway temperature induced protein extravasation in the major airways and lung tissue of sensitized rats, and an activation of the NK-1 receptor by tachykinins released from bronchopulmonary C-fiber nerve endings was primarily responsible. PMID:25864799

Are atmospheric surface layer flows ergodic?

NASA Astrophysics Data System (ADS)

Higgins, Chad W.; Katul, Gabriel G.; Froidevaux, Martin; Simeonov, Valentin; Parlange, Marc B.

2013-06-01

The transposition of atmospheric turbulence statistics from the time domain, as conventionally sampled in field experiments, is explained by the so-called ergodic hypothesis. In micrometeorology, this hypothesis assumes that the time average of a measured flow variable represents an ensemble of independent realizations from similar meteorological states and boundary conditions. That is, the averaging duration must be sufficiently long to include a large number of independent realizations of the sampled flow variable so as to represent the ensemble. While the validity of the ergodic hypothesis for turbulence has been confirmed in laboratory experiments, and numerical simulations for idealized conditions, evidence for its validity in the atmospheric surface layer (ASL), especially for nonideal conditions, continues to defy experimental efforts. There is some urgency to make progress on this problem given the proliferation of tall tower scalar concentration networks aimed at constraining climate models yet are impacted by nonideal conditions at the land surface. Recent advancements in water vapor concentration lidar measurements that simultaneously sample spatial and temporal series in the ASL are used to investigate the validity of the ergodic hypothesis for the first time. It is shown that ergodicity is valid in a strict sense above uniform surfaces away from abrupt surface transitions. Surprisingly, ergodicity may be used to infer the ensemble concentration statistics of a composite grass-lake system using only water vapor concentration measurements collected above the sharp transition delineating the lake from the grass surface.

The Pivotal Role of Airway Smooth Muscle in Asthma Pathophysiology

PubMed Central

Ozier, Annaïg; Allard, Benoit; Bara, Imane; Girodet, Pierre-Olivier; Trian, Thomas; Marthan, Roger; Berger, Patrick

2011-01-01

Asthma is characterized by the association of airway hyperresponsiveness (AHR), inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM) in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/load coupling. Beyond its contractile function, ASM is also involved in bronchial inflammation and remodelling. Whereas ASM is a target of the inflammatory process, it can also display proinflammatory and immunomodulatory functions, through its synthetic properties and the expression of a wide range of cell surface molecules. ASM remodelling represents a key feature of asthmatic bronchial remodelling. ASM also plays a role in promoting complementary airway structural alterations, in particular by its synthetic function. PMID:22220184

Experimental data and model for the turbulent boundary layer on a convex, curved surface

NASA Technical Reports Server (NTRS)

Gillis, J. C.; Johnson, J. P.; Moffat, R. J.; Kays, W. M.

1981-01-01

Experiments were performed to determine how boundary layer turbulence is affected by strong convex curvature. The data gathered on the behavior of the Reynolds stress suggested the formulation of a simple turbulence model. Data were taken on two separate facilities. Both rigs had flow from a flat surface, over a convex surface with 90 deg of turning and then onto a flat recovery surface. The geometry was adjusted so that, for both rigs, the pressure gradient along the test surface was zero. Two experiments were performed at delta/R approximately 0.10, and one at weaker curvature with delta/R approximately 0.05. Results show that after a sudden introduction of curvature the shear stress in the outer part of the boundary layer is sharply diminished and is even slightly negative near the edge. The wall shear also drops off quickly downstream. When the surface suddenly becomes flat again, the wall shear and shear stress profiles recover very slowly towards flat wall conditions. A simple turbulence model, which was based on the theory that the Prandtl mixing length in the outer layer should scale on the velocity gradient layer, was shown to account for the slow recovery.

Surface plasmon dispersion engineering via double-metallic AU/AG layers for nitride light-emitting diodes

DOEpatents

Tansu, Nelson; Zhao, Hongping; Zhang, Jing; Liu, Guangyu

2014-04-01

A double-metallic deposition process is used whereby adjacent layers of different metals are deposited on a substrate. The surface plasmon frequency of a base layer of a first metal is tuned by the surface plasmon frequency of a second layer of a second metal formed thereon. The amount of tuning is dependent upon the thickness of the metallic layers, and thus tuning can be achieved by varying the thicknesses of one or both of the metallic layers. In a preferred embodiment directed to enhanced LED technology in the green spectrum regime, a double-metallic Au/Ag layer comprising a base layer of gold (Au) followed by a second layer of silver (Ag) formed thereon is deposited on top of InGaN/GaN quantum wells (QWs) on a sapphire/GaN substrate.

Regulation of Cl^- Channels in Normal and Cystic Fibrosis Airway Epithelial Cells by Extracellular ATP

NASA Astrophysics Data System (ADS)

Stutts, M. J.; Chinet, T. C.; Mason, S. J.; Fullton, J. M.; Clarke, L. L.; Boucher, R. C.

1992-03-01

The rate of Cl^- secretion by human airway epithelium is determined, in part, by apical cell membrane Cl^- conductance. In cystic fibrosis airway epithelia, defective regulation of Cl^- conductance decreases the capability to secrete Cl^-. Here we report that extracytosolic ATP in the luminal bath of cultured human airway epithelia increased transepithelial Cl^- secretion and apical membrane Cl^- permeability. Single-channel studies in excised membrane patches revealed that ATP increased the open probability of outward rectifying Cl^- channels. The latter effect occurs through a receptor mechanism that requires no identified soluble second messengers and is insensitive to probes of G protein function. These results demonstrate a mode of regulation of anion channels by binding ATP at the extracellular surface. Regulation of Cl^- conductance by external ATP is preserved in cystic fibrosis airway epithelia.

Paraneurons in the gills and airways of fishes.

PubMed

Zaccone, G; Fasulo, S; Ainis, L; Licata, A

1997-04-01

This chapter describes the distributional patterns of the neuroendocrine cells in the respiratory surfaces of fishes and their bioactive secretions which are compared with similar elements in higher vertebrates. The neuroendocrine cells in the airways of fishes differentiate as solitary and clustered cells, but the clusters are not converted into neuroepithelial bodies which are reported in terrestrial vertebrates. The dipnoan fish Protopterus has innervated neuroendocrine cells in the pneumatic duct region. In Polypterus and Amia the lungs have neuroendocrine cells that are apparently not innervated. Two types of neuroendocrine cells are found in the gill of teleost fishes. These cells are very different by their location, structure and immunohistochemistry. Advanced studies on functional morphology of neuroendocrine cells in fish airways are still necessary to increase our understanding of their multifunctional role in the gill area.

Boundary layer transition observations on a body of revolution with surface heating and cooling in water

NASA Astrophysics Data System (ADS)

Arakeri, V. H.

1980-04-01

Boundary layer flow visualization in water with surface heat transfer was carried out on a body of revolution which had the predicted possibility of laminar separation under isothermal conditions. Flow visualization was by in-line holographic technique. Boundary layer stabilization, including elimination of laminar separation, was observed to take place on surface heating. Conversely, boundary layer destabilization was observed on surface cooling. These findings are consistent with the theoretical predictions of Wazzan et al. (1970).

Functionalised nanoscale coatings using layer-by-layer assembly for imparting antibacterial properties to polylactide-co-glycolide surfaces.

PubMed

Gentile, Piergiorgio; Frongia, Maria E; Cardellach, Mar; Miller, Cheryl A; Stafford, Graham P; Leggett, Graham J; Hatton, Paul V

2015-07-01

In order to achieve high local biological activity and reduce the risk of side effects of antibiotics in the treatment of periodontal and bone infections, a localised and temporally controlled delivery system is desirable. The aim of this research was to develop a functionalised and resorbable surface to contact soft tissues to improve the antibacterial behaviour during the first week after its implantation in the treatment of periodontal and bone infections. Solvent-cast poly(d,l-lactide-co-glycolide acid) (PLGA) films were aminolysed and then modified by Layer-by-Layer technique to obtain a nano-layered coating using poly(sodium4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) as polyelectrolytes. The water-soluble antibiotic, metronidazole (MET), was incorporated from the ninth layer. Infrared spectroscopy showed that the PSS and PAH absorption bands increased with the layer number. The contact angle values had a regular alternate behaviour from the ninth layer. X-ray Photoelectron Spectroscopy evidenced two distinct peaks, N1s and S2p, indicating PAH and PSS had been introduced. Atomic Force Microscopy showed the presence of polyelectrolytes on the surface with a measured roughness about 10nm after 20 layers' deposition. The drug release was monitored by Ultraviolet-visible spectroscopy showing 80% loaded-drug delivery in 14 days. Finally, the biocompatibility was evaluated in vitro with L929 mouse fibroblasts and the antibacterial properties were demonstrated successfully against the keystone periodontal bacteria Porphyromonas gingivalis, which has an influence on implant failure, without compromising in vitro biocompatibility. In this study, PLGA was successfully modified to obtain a localised and temporally controlled drug delivery system, demonstrating the potential value of LbL as a coating technology for the manufacture of medical devices with advanced functional properties. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd

Effect of tethering on the surface dynamics of a thin polymer melt layer

DOE PAGES

Uğur, Gökçe; Akgun, Bulent; Jiang, Zhang; ...

2016-05-13

The surface height fluctuations of a layer of low molecular weight (2.2k) untethered perdeuterated polystyrene (dPS) chains adjacent to a densely grafted polystyrene brush are slowed dramatically. Due to the interpenetration of the brush with the layer of “untethered chains” a hydrodynamic continuum theory can only describe the fluctuations when the effective thickness of the film is taken to be that which remains above the swollen brush. Furthermore, the portion of the film of initially untethered chains that interpenetrates with the brush becomes so viscous as to effectively play the role of a rigid substrate. They provide a route formore » tailoring polymer layer surface properties such as wetting, adhesion and friction, since these hybrid samples contain a covalently tethered layer at the bottom, does not readily dewet, and are more robust than thin layers of untethered short chains on rigid substrates.« less

Effect of tethering on the surface dynamics of a thin polymer melt layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uğur, Gökçe; Akgun, Bulent; Jiang, Zhang

The surface height fluctuations of a layer of low molecular weight (2.2k) untethered perdeuterated polystyrene (dPS) chains adjacent to a densely grafted polystyrene brush are slowed dramatically. Due to the interpenetration of the brush with the layer of “untethered chains” a hydrodynamic continuum theory can only describe the fluctuations when the effective thickness of the film is taken to be that which remains above the swollen brush. Furthermore, the portion of the film of initially untethered chains that interpenetrates with the brush becomes so viscous as to effectively play the role of a rigid substrate. They provide a route formore » tailoring polymer layer surface properties such as wetting, adhesion and friction, since these hybrid samples contain a covalently tethered layer at the bottom, does not readily dewet, and are more robust than thin layers of untethered short chains on rigid substrates.« less

Microstructures of tribologically modified surface layers in two-phase alloys

NASA Astrophysics Data System (ADS)

Figueroa, C. G.; Ortega, I.; Jacobo, V. H.; Ortiz, A.; Bravo, A. E.; Schouwenaars, R.

2014-08-01

When ductile alloys are subject to sliding wear, small increments of plastic strain accumulate into severe plastic deformation and mechanical alloying of the surface layer. The authors constructed a simple coaxial tribometer, which was used to study this phenomenon in wrought Al-Sn and cast Cu-Mg-Sn alloys. The first class of materials is ductile and consists of two immiscible phases. Tribological modification is observed in the form of a transition zone from virgin material to severely deformed grains. At the surface, mechanical mixing of both phases competes with diffusional unmixing. Vortex flow patterns are typically observed. The experimental Cu-Mg-Sn alloys are ductile for Mg-contents up to 2 wt% and consist of a- dendrites with a eutectic consisting of a brittle Cu2Mg-matrix with α-particles. In these, the observations are similar to the Al-Sn Alloys. Alloys with 5 wt% Mg are brittle due to the contiguity of the eutectic compound. Nonetheless, under sliding contact, this compound behaves in a ductile manner, showing mechanical mixing of a and Cu2Mg in the top layers and a remarkable transition from a eutectic to cellular microstructure just below, due to severe shear deformation. AFM-observations allow identifying the mechanically homogenized surface layers as a nanocrystalline material with a cell structure associated to the sliding direction.

Interleukin-1beta-induced airway hyperresponsiveness enhances substance P in intrinsic neurons of ferret airway.

PubMed

Wu, Z-X; Satterfield, B E; Fedan, J S; Dey, R D

2002-11-01

Interleukin (IL)-1beta causes airway inflammation, enhances airway smooth muscle responsiveness, and alters neurotransmitter expression in sensory, sympathetic, and myenteric neurons. This study examines the role of intrinsic airway neurons in airway hyperresponsiveness (AHR) induced by IL-1beta. Ferrets were instilled intratracheally with IL-1beta (0.3 microg/0.3 ml) or saline (0.3 ml) once daily for 5 days. Tracheal smooth muscle contractility in vitro and substance P (SP) expression in tracheal neurons were assessed. Tracheal smooth muscle reactivity to acetylcholine (ACh) and methacholine (MCh) and smooth muscle contractions to electric field stimulation (EFS) both increased after IL-1beta. The IL-1beta-induced AHR was maintained in tracheal segments cultured for 24 h, a procedure that depletes SP from sensory nerves while maintaining viability of intrinsic airway neurons. Pretreatment with CP-99994, an antagonist of neurokinin 1 receptor, attenuated the IL-1beta-induced hyperreactivity to ACh and MCh and to EFS in cultured tracheal segments. SP-containing neurons in longitudinal trunk, SP innervation of superficial muscular plexus neurons, and SP nerve fiber density in tracheal smooth muscle all increased after treatment with IL-1beta. These results show that IL-1beta-enhanced cholinergic airway smooth muscle contractile responses are mediated by the actions of SP released from intrinsic airway neurons.

Effect of a Dusty Layer on Surface-Wave Produced Plasmas

NASA Astrophysics Data System (ADS)

Ostrikov, Kostyantyn; Yu, Ming; Xu, Shuyan

2000-10-01

The effect of near-sheath dusts on the RF power loss in a surface-wave sustained gas discharge is studied. The planar plasma is bounded by a dielectric and consists of an inhomogeneous near-wall transition layer (sheath), a dusty plasma layer, and the outer dust-free plasma. The discharge is maintained by high-frequency axially-symmetric surface waves. The surface-wave power loss from the most relevant dissipative mechanisms in typical discharge plasmas is analyzed. Our model allows one to consider the main effects of dust particles on surface-wave produced discharge plasmas. We demonstrate that the dusts released in the discharge can strongly modify the plasma conductivity and lead to a significant redistribution of the total charge. They affect the electron quasi-momenta, but do not absorb the energy transmitted to the plasma through elastic collisions, and therefore they remain cold at the room temperature. It is shown that the improvement of the efficiency of energy transfer from the wave source to the plasma can be achieved by selecting operation regimes when the efficiency of the power loss in the plasma through electron-neutral collisions is higher than that through electron-dust interactions.

Control of Alq3 wetting layer thickness via substrate surface functionalization.

PubMed

Tsoi, Shufen; Szeto, Bryan; Fleischauer, Michael D; Veinot, Jonathan G C; Brett, Michael J

2007-06-05

The effects of substrate surface energy and vapor deposition rate on the initial growth of porous columnar tris(8-hydroxyquinoline)aluminum (Alq3) nanostructures were investigated. Alq3 nanostructures thermally evaporated onto as-supplied Si substrates bearing an oxide were observed to form a solid wetting layer, likely caused by an interfacial energy mismatch between the substrate and Alq3. Wetting layer thickness control is important for potential optoelectronic applications. A dramatic decrease in wetting layer thickness was achieved by depositing Alq3 onto alkyltrichlorosilane-derivatized Si/oxide substrates. Similar effects were noted with increasing deposition rates. These two effects enable tailoring of the wetting layer thickness.

Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

NASA Technical Reports Server (NTRS)

Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.;

Effect of the Parameters of Gas-Powder Laser Surfacing on the Structural Characteristics of Reconditioned Surface Layer of Corrosion-Resistant Steels

NASA Astrophysics Data System (ADS)

Krylova, S. E.; Oplesnin, S. P.; Manakov, N. A.; Yasakov, A. S.; Strizhov, A. O.

2018-01-01

Results of the developed commercial process for reconditioning the surface of corrosion-resistant steels by the method of laser surfacing are presented. A comparative analysis of the microstructures of the deposited wear-resistant layer, of the zone of fusion with the matrix material and of the diffusion zone after different variants of surfacing is performed. The hardness of the deposited layer is measured and a nondestructive inspection of the latter for the presence of flaws is performed.

Critical role of actin-associated proteins in smooth muscle contraction, cell proliferation, airway hyperresponsiveness and airway remodeling.

PubMed

Tang, Dale D

2015-10-30

Asthma is characterized by airway hyperresponsiveness and airway remodeling, which are largely attributed to increased airway smooth muscle contractility and cell proliferation. It is known that both chemical and mechanical stimulation regulates smooth muscle contraction. Recent studies suggest that contractile activation and mechanical stretch induce actin cytoskeletal remodeling in smooth muscle. However, the mechanisms that control actin cytoskeletal reorganization are not completely elucidated. This review summarizes our current understanding regarding how actin-associated proteins may regulate remodeling of the actin cytoskeleton in airway smooth muscle. In particular, there is accumulating evidence to suggest that Abelson tyrosine kinase (Abl) plays a critical role in regulating airway smooth muscle contraction and cell proliferation in vitro, and airway hyperresponsiveness and remodeling in vivo. These studies indicate that Abl may be a novel target for the development of new therapy to treat asthma.

Repurposing tromethamine as inhaled therapy to treat CF airway disease

PubMed Central

Alaiwa, Mahmoud H. Abou; Launspach, Janice L.; Sheets, Kelsey A.; Rivera, Jade A.; Gansemer, Nicholas D.; Taft, Peter J.; Thorne, Peter S.; Welsh, Michael J.; Stoltz, David A.

2016-01-01

In cystic fibrosis (CF), loss of CF transmembrane conductance regulator (CFTR) anion channel activity causes airway surface liquid (ASL) pH to become acidic, which impairs airway host defenses. One potential therapeutic approach is to correct the acidic pH in CF airways by aerosolizing HCO3– and/or nonbicarbonate pH buffers. Here, we show that raising ASL pH with inhaled HCO3– increased pH. However, the effect was transient, and pH returned to baseline values within 30 minutes. Tromethamine (Tham) is a buffer with a long serum half-life used as an i.v. formulation to treat metabolic acidosis. We found that Tham aerosols increased ASL pH in vivo for at least 2 hours and enhanced bacterial killing. Inhaled hypertonic saline (7% NaCl) is delivered to people with CF in an attempt to promote mucus clearance. Because an increased ionic strength inhibits ASL antimicrobial factors, we added Tham to hypertonic saline and applied it to CF sputum. We found that Tham alone and in combination with hypertonic saline increased pH and enhanced bacterial killing. These findings suggest that aerosolizing the HCO3–-independent buffer Tham, either alone or in combination with hypertonic saline, might be of therapeutic benefit in CF airway disease. PMID:27390778

A 'Good' muscle in a 'Bad' environment: the importance of airway smooth muscle force adaptation to airway hyperresponsiveness.

PubMed

Bossé, Ynuk; Chapman, David G; Paré, Peter D; King, Gregory G; Salome, Cheryl M

2011-12-15

Asthma is characterized by airway inflammation, with a consequent increase in spasmogens, and exaggerated airway narrowing in response to stimuli, termed airway hyperresponsiveness (AHR). The nature of any relationship between inflammation and AHR is less clear. Recent ex vivo data has suggested a novel mechanism by which inflammation may lead to AHR, in which increased basal ASM-tone, due to the presence of spasmogens in the airways, may "strengthen" the ASM and ultimately lead to exaggerated airway narrowing. This phenomenon was termed "force adaptation" [Bossé, Y., Chin, L.Y., Paré, P.D., Seow, C.Y., 2009. Adaptation of airway smooth muscle to basal tone: relevance to airway hyperresponsiveness. Am. J. Respir. Cell Mol. Biol. 40, 13-18]. However, it is unknown whether the magnitude of the effect of force adaptation ex vivo could contribute to exaggerated airway narrowing in vivo. Our aim was to utilize a computational model of ASM shortening in order to quantify the potential effect of force adaptation on airway narrowing when all other mechanical factors were kept constant. The shortening in the model is dictated by a balance between physiological loads and ASM force-generating capacity at different lengths. The results suggest that the magnitude of the effect of force adaptation on ASM shortening would lead to substantially more airway narrowing during bronchial challenge at any given airway generation. We speculate that the increased basal ASM-tone in asthma, due to the presence of inflammation-derived spasmogens, produces an increase in the force-generating capacity of ASM, predisposing to AHR during subsequent challenge. Copyright © 2011 Elsevier B.V. All rights reserved.

Thickened boundary layer theory for air film drag reduction on a van body surface

NASA Astrophysics Data System (ADS)

Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

2018-05-01

To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

Mechanotransduction, asthma, and airway smooth muscle

PubMed Central

Fabry, Ben; Fredberg, Jeffrey J.

2008-01-01

Excessive force generation by airway smooth muscle is the main culprit in excessive airway narrowing during an asthma attack. The maximum force the airway smooth muscle can generate is exquisitely sensitive to muscle length fluctuations during breathing, and is governed by complex mechanotransduction events that can best be studied by a hybrid approach in which the airway wall is modeled in silico so as to set a dynamic muscle load comparable to that experienced in vivo. PMID:18836522

Purification and characterization of Campylobacter rectus surface layer proteins.

PubMed Central

Nitta, H; Holt, S C; Ebersole, J L

1997-01-01

Campylobacter rectus is a putative periodontopathogen which expresses a proteinaceous surface layer (S-layer) external to the outer membrane. S-layers are considered to play a protective role for the microorganism in hostile environments. The S-layer proteins from six different C. rectus strains (five human isolates and a nonhuman primate [NHP] isolate) were isolated, purified, and characterized. The S-layer proteins of these strains varied in molecular mass (ca. 150 to 166 kDa) as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. They all reacted with monospecific rabbit antiserum to the purified S-layer of C. rectus 314, but a quantitative enzyme-linked immunosorbent assay demonstrated a strong antigenic relationship among the five human strains, while the NHP strain, 6250, showed weaker reactivity. Amino acid composition analysis showed that the S-layers of four C. rectus strains contained large proportions of acidic amino acids (13 to 27%) and that >34% of the amino acid residues were hydrophobic. Amino acid sequence analysis of six S-layer proteins revealed that the first 15 amino-terminal amino acids were identical and showed seven residues of identity with the amino-terminal sequence of the Campylobacter fetus S-layer protein SapA1. CNBr peptide profiles of the S-layer proteins from C. rectus 314, ATCC 33238, and 6250 confirmed that the S-layer proteins from the human strains were similar to each other and somewhat different from that of the NHP isolate (strain 6250). However, the S-layer proteins from the two human isolates do show some structural heterogeneity. For example, there was a 17-kDa fragment unique to the C. rectus 314 S-layer. The amino-terminal sequence of this peptide had homology with the C. rectus 51-kDa porin and was composed of nearly 50% hydrophobic residues. Thus, the S-layer protein from C. rectus has structural heterogeneity among different human strains and immunoheterogeneity with the NHP strain. PMID:9009300

Cardiovascular causes of airway compression.

PubMed

Kussman, Barry D; Geva, Tal; McGowan, Francis X

2004-01-01

Compression of the paediatric airway is a relatively common and often unrecognized complication of congenital cardiac and aortic arch anomalies. Airway obstruction may be the result of an anomalous relationship between the tracheobronchial tree and vascular structures (producing a vascular ring) or the result of extrinsic compression caused by dilated pulmonary arteries, left atrial enlargement, massive cardiomegaly, or intraluminal bronchial obstruction. A high index of suspicion of mechanical airway compression should be maintained in infants and children with recurrent respiratory difficulties, stridor, wheezing, dysphagia, or apnoea unexplained by other causes. Prompt diagnosis is required to avoid death and minimize airway damage. In addition to plain chest radiography and echocardiography, diagnostic investigations may consist of barium oesophagography, magnetic resonance imaging (MRI), computed tomography, cardiac catheterization and bronchoscopy. The most important recent advance is MRI, which can produce high quality three-dimensional reconstruction of all anatomic elements allowing for precise anatomic delineation and improved surgical planning. Anaesthetic technique will depend on the type of vascular ring and the presence of any congenital heart disease or intrinsic lesions of the tracheobronchial tree. Vascular rings may be repaired through a conventional posterolateral thoracotomy, or utilizing video-assisted thoracoscopic surgery (VATS) or robotic endoscopic surgery. Persistent airway obstruction following surgical repair may be due to residual compression, secondary airway wall instability (malacia), or intrinsic lesions of the airway. Simultaneous repair of cardiac defects and vascular tracheobronchial compression carries a higher risk of morbidity and mortality.

Properties of Surface-Modification Layer Generated by Atomic Hydrogen Annealing on Poly(ethylene naphthalate) Substrate

NASA Astrophysics Data System (ADS)

Heya, Akira; Matsuo, Naoto

2008-01-01

The surface of a poly(ethylene naphthalate) (PEN) substrate was modified by atomic hydrogen annealing (AHA). In this method, a PEN substrate was exposed to atomic hydrogen generated by cracking hydrogen molecules on heated tungsten wire. The properties of the surface-modification layer by AHA were evaluated by spectroscopic ellipsometry. It is found that the thickness of the modified layer was 5 nm and that the modification layer has a low refractive index compared with the PEN substrate. The modification layer relates to the reduction reaction of the PEN substrate by AHA.

21 CFR 868.2600 - Airway pressure monitor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper airway...

Surface acoustic waves in acoustic superlattice lithium niobate coated with a waveguide layer

NASA Astrophysics Data System (ADS)

Yang, G. Y.; Du, J. K.; Huang, B.; Jin, Y. A.; Xu, M. H.

2017-04-01

The effects of the waveguide layer on the band structure of Rayleigh waves are studied in this work based on a one-dimensional acoustic superlattice lithium niobate substrate coated with a waveguide layer. The present phononic structure is formed by the periodic domain-inverted single crystal that is the Z-cut lithium niobate substrate with a waveguide layer on the upper surface. The plane wave expansion method (PWE) is adopted to determine the band gap behavior of the phononic structure and validated by the finite element method (FEM). The FEM is also used to investigate the transmission of Rayleigh waves in the phononic structure with the interdigital transducers by means of the commercial package COMSOL. The results show that, although there is a homogeneous waveguide layer on the surface, the band gap of Rayleigh waves still exist. It is also found that increasing the thickness of the waveguide layer, the band width narrows and the band structure shifts to lower frequency. The present approach can be taken as an efficient tool in designing of phononic structures with waveguide layer.

Surface-enhanced Raman spectroscopy on coupled two-layer nanorings

NASA Astrophysics Data System (ADS)

Hou, Yumin; Xu, Jun; Wang, Pengwei; Yu, Dapeng

2010-05-01

A reproducible quasi-three-dimensional structure, composed of top and bottom concentric nanorings with same periodicity but different widths and no overlapping at the perpendicular direction, is built up by a separation-layer method, which results in huge enhancement of surface-enhanced Raman spectroscopy (SERS) due to the coupling of plasmons. Simulations show plasmonic focusing with "hot arcs" of electromagnetic enhancement meeting the need of quantitative SERS with extremely high sensitivities. In addition, the separation-layer method opens a simple and effective way to adjust the coupling of plasmons among nanostructures which is essential for the fabrication of SERS-based sensors.

Surface Properties of PEMFC Gas Diffusion Layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

WoodIII, David L; Rulison, Christopher; Borup, Rodney

2010-01-01

The wetting properties of PEMFC Gas Diffusion Layers (GDLs) were quantified by surface characterization measurements and modeling of material properties. Single-fiber contact-angle and surface energy (both Zisman and Owens-Wendt) data of a wide spectrum of GDL types is presented to delineate the effects of hydrophobic post-processing treatments. Modeling of the basic sessile-drop contact angle demonstrates that this value only gives a fraction of the total picture of interfacial wetting physics. Polar forces are shown to contribute 10-20 less than dispersive forces to the composite wetting of GDLs. Internal water contact angles obtained from Owens-Wendt analysis were measured at 13-19 highermore » than their single-fiber counterparts. An inverse relationship was found between internal contact angle and both Owens-Wendt surface energy and % polarity of the GDL. The most sophisticated PEMFC mathematical models use either experimentally measured capillary pressures or the standard Young-Laplace capillary-pressure equation. Based on the results of the Owens-Wendt analysis, an advancement to the Young-Laplace equation is proposed for use in these mathematical models, which utilizes only solid surface energies and fractional surface coverage of fluoropolymer. Capillary constants for the spectrum of analyzed GDLs are presented for the same purpose.« less

Awake Craniotomy: A New Airway Approach.

PubMed

Sivasankar, Chitra; Schlichter, Rolf A; Baranov, Dimitry; Kofke, W Andrew

2016-02-01

Awake craniotomies have been performed regularly at the University of Pennsylvania since 2004. Varying approaches to airway management are described for this procedure, including intubation with an endotracheal tube and use of a laryngeal mask airway, simple facemask, or nasal cannula. In this case series, we describe the successful use (i.e., no need for endotracheal intubation related to inadequate gas exchange) of bilateral nasopharyngeal airways in 90 patients undergoing awake craniotomies. The use of nasopharyngeal airways can ease the transition between the asleep and awake phases of the craniotomy without the need to stimulate the airway. Our purpose was to describe our experience and report adverse events related to this technique.

Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity

PubMed Central

Mezger, Markus; Ocko, Benjamin M.; Reichert, Harald; Deutsch, Moshe

2013-01-01

The molecular-scale structure of the ionic liquid [C18mim]+[FAP]− near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing. PMID:23431181

Airway structure and function in Eisenmenger's syndrome.

PubMed

McKay, K O; Johnson, P R; Black, J L; Glanville, A R; Armour, C L

1998-10-01

The responsiveness of airways from patients with Eisenmenger's syndrome (n = 5) was compared with that in airways from organ donors (n = 10). Enhanced contractile responses to cholinergic stimulation were found in airways from patients with Eisenmenger's syndrome. The maximal responses to acetylcholine, carbachol, and parasympathetic nerve stimulation in airway tissue from these patients were 221%, 139%, and 152%, respectively, of the maximal responses obtained in donor tissue. Further, relaxation responses to isoproterenol and levocromakalim were absent (n = 2) or markedly impaired (n = 3) in airways from patients with Eisenmenger's syndrome. This attenuated relaxation response was nonspecific in that it was also absent after vasoactive intestinal peptide, sodium nitroprusside, papaverine, and electrical field application. These observations can most likely be explained by a decrease in intrinsic smooth muscle tone, as precontraction of airways revealed relaxation responses that were equivalent to those obtained in donor tissues. Morphometric analysis of tissues used for the functional studies revealed no differences in the airway dimensions (internal perimeter) or airway wall components (e.g., smooth muscle, cartilage) or total area to explain these observations. Although the mechanism for this observed decrease in intrinsic airway smooth muscle tone is not certain, it may be due to alteration in the substructure of the airway wall or, alternatively, may result from the continued release of depressant factors in the vicinity of the smooth muscle which permanently alters smooth muscle responsiveness.

Rough SERS substrate based on gold coated porous silicon layer prepared on the silicon backside surface

NASA Astrophysics Data System (ADS)

Dridi, H.; Haji, L.; Moadhen, A.

2017-04-01

We report in this paper a novel method to elaborate rough Surface Enhanced Raman Scattering (SERS) substrate. A single layer of porous silicon was formed on the silicon backside surface. Morphological characteristics of the porous silicon layer before and after gold deposition were influenced by the rough character (gold size). The reflectance measurements showed a dependence of the gold nano-grains size on the surface nature, through the Localized Surface Plasmon (LSP) band properties. SERS signal of Rhodamine 6G used as a model analyte, adsorbed on the rough porous silicon layer revealed a marked enhancement of its vibrational modes intensities.

A meta-analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates.

PubMed

Hubble, Michael W; Wilfong, Denise A; Brown, Lawrence H; Hertelendy, Attila; Benner, Randall W

2010-01-01

Airway management is a key component of prehospital care for seriously ill and injured patients. Oral endotracheal intubation (OETI) is the definitive airway of choice in most emergency medical services (EMS) systems. However, OETI may not be an approved skill for some clinicians or may prove problematic in certain patients because of anatomic abnormalities, trauma, or inadequate relaxation. In these situations alternative airways are frequently employed. However, the reported success rates for these devices vary widely, and established benchmarks are lacking. We sought to determine pooled estimates of the success rates of alternative airway devices (AADs) and needle cricothyrotomy (NCRIC) and surgical cricothyrotomy (SCRIC) placement through a meta-analysis of the literature. We performed a systematic literature search for all English-language articles reporting success rates for AADs, SCRIC, and NCRIC. Studies of field procedures performed by prehospital personnel from any nation were included. All titles were reviewed independently by two authors using prespecified inclusion criteria. Pooled estimates of success rates for each airway technique were calculated using a random-effects meta-analysis model. Of 2,005 prehospital airway titles identified, 35 unique studies were retained for analysis of AAD success rates, encompassing a total of 10,172 prehospital patients. The success rates for SCRIC and NCRIC were analyzed across an additional 21 studies totaling 512 patients. The pooled estimates (and 95% confidence intervals [CIs]) for intervention success across all clinicians and patients were as follows: esophageal obturator airway-esophageal gastric tube airway (EOA-EGTA) 92.6% (90.1%-94.5%); pharyngeotracheal lumen airway (PTLA) 82.1% (74.0%-88.0%); esophageal-tracheal Combitube (ETC) 85.4% (77.3%-91.0%); laryngeal mask airway (LMA) 87.4% (79.0%-92.8%); King Laryngeal Tube airway (King LT) 96.5% (71.2%-99.7%); NCRIC 65.8% (42.3%-83.59%); and SCRIC 90.5% (84

Observations of the Evolution of Turbulent Dissipation within the Ocean Surface Boundary Layer: an OSMOSIS study

NASA Astrophysics Data System (ADS)

Lucas, N. S.; Allen, J.; Belcher, S. E.; Boyd, T.; Brannigan, L.; Inall, M.; Palmer, M.; Polton, J.; Rippeth, T. P.

2016-02-01

This study presents a new 9.5 day dataset showing the evolution of the Ocean Surface Boundary Layer (OSBL) and dissipation of turbulence kinetic energy (TKE), carried out as part of OSMOSIS[i], at a location in the North East Atlantic Ocean in September 2012. The TKE dissipation measurements were made using three methods; (i) repeated profiling between 100m and the surface by an Ocean Microstructure glider, (ii) three series of profiles made using a loosely tethered velocity microstructure glider and (iii) a moored pulse-pulse coherent high frequency ADCP. Supporting measurements show the evolution of the water column structure, including surface wave measurements from a TRIAXYS wave buoy. This data shows two distinct regimes; the first, spanning 4 days with relatively low winds, displays a distinct diurnal cycle with the deepening of the active mixing layer during the night which shoaled during the day. The second spanned a significant storm, (with maximum winds speeds reaching 20 m s-1 and significant wave heights reaching 6 m), during which, rather than a deepening of the mixed layer as predicted by classical theory, the primary effect was a broadening of the transition layer, similar to that found by Dohan and Davies (2011). During the storm, significant dissipation was observed throughout the surface mixed layer and into the transition layer, driving fluxes of heat downwards through the base of the surface mixed layer. [i] Ocean Surface Mixing and Submesoscale Interaction Study Dohan, K. & Davis, R.E., 2011. Mixing in the Transition Layer during Two Storm Events. Journal of Physical Oceanography. 41 (1). pp. 42-66.

The development of self-expanding peripheral stent with ion-modified surface layer

NASA Astrophysics Data System (ADS)

Lotkov, Alexander I.; Kashin, Oleg A.; Kudryashov, Andrey N.; Krukovskii, Konstantin V.; Kuznetsov, Vladimir M.; Borisov, Dmitry P.; Kretov, Evgenii I.

2016-11-01

In work researches of chemical composition of surface layers of self-expanding stents of nickel-titanium (NiTi) and their functional and mechanical properties after plasma immersion processing by ions of silicon (Si). It is established that in the treatment in the inner and outer surfaces of stents formed doped silicon layer with a thickness of 80 nm. The formation of the doped layer does not impair the functional properties of the stent. At human body temperature, the stent is fully restore its shape after removing the deforming load. The resulting graph of loading of stents during their compression between parallel plates. The research results allow the conclusion that Si-doped stents are promising for treatment of peripheral vascular disease. However, related studies on laboratory animals are required.

Investigating the geometry of pig airways using computed tomography

NASA Astrophysics Data System (ADS)

Mansy, Hansen A.; Azad, Md Khurshidul; McMurray, Brandon; Henry, Brian; Royston, Thomas J.; Sandler, Richard H.

2015-03-01

Numerical modeling of sound propagation in the airways requires accurate knowledge of the airway geometry. These models are often validated using human and animal experiments. While many studies documented the geometric details of the human airways, information about the geometry of pig airways is scarcer. In addition, the morphology of animal airways can be significantly different from that of humans. The objective of this study is to measure the airway diameter, length and bifurcation angles in domestic pigs using computed tomography. After imaging the lungs of 3 pigs, segmentation software tools were used to extract the geometry of the airway lumen. The airway dimensions were then measured from the resulting 3 D models for the first 10 airway generations. Results showed that the size and morphology of the airways of different animals were similar. The measured airway dimensions were compared with those of the human airways. While the trachea diameter was found to be comparable to the adult human, the diameter, length and branching angles of other airways were noticeably different from that of humans. For example, pigs consistently had an early airway branching from the trachea that feeds the superior (top) right lung lobe proximal to the carina. This branch is absent in the human airways. These results suggested that the human geometry may not be a good approximation of the pig airways and may contribute to increasing the errors when the human airway geometric values are used in computational models of the pig chest.

Effect of airway acidosis and alkalosis on airway vascular smooth muscle responsiveness to albuterol.

PubMed

Cancado, Jose E; Mendes, Eliana S; Arana, Johana; Horvath, Gabor; Monzon, Maria E; Salathe, Matthias; Wanner, Adam

2015-04-02

In vitro and animal experiments have shown that the transport and signaling of β2-adrenergic agonists are pH-sensitive. Inhaled albuterol, a hydrophilic β2-adrenergic agonist, is widely used for the treatment of obstructive airway diseases. Acute exacerbations of obstructive airway diseases can be associated with changes in ventilation leading to either respiratory acidosis or alkalosis thereby affecting albuterol responsiveness in the airway. The purpose of this study was to determine if airway pH has an effect on albuterol-induced vasodilation in the airway. Ten healthy volunteers performed the following respiratory maneuvers: quiet breathing, hypocapnic hyperventilation, hypercapnic hyperventilation, and eucapnic hyperventilation (to dissociate the effect of pH from the effect of ventilation). During these breathing maneuvers, exhaled breath condensate (EBC) pH and airway blood flow response to inhaled albuterol (ΔQ̇aw) were assessed. Mean ± SE EBC pH (units) and ΔQ̇aw (μl.min(-1).mL(-1)) were 6.4 ± 0.1 and 16.8 ± 1.9 during quiet breathing, 6.3 ± 0.1 and 14.5 ± 2.4 during eucapnic hyperventilation, 6.6 ± 0.2 and -0.2 ± 1.8 during hypocapnic hyperventilation (p = 0.02 and <0.01 vs. quiet breathing), and 5.9 ± 0.1 and 2.0 ± 1.5 during hypercapnic hyperventilation (p = 0.02 and <0.02 vs quiet breathing). Albuterol responsiveness in the airway as assessed by ΔQ̇aw is pH sensitive. The breathing maneuver associated with decreased and increased EBC pH both resulted in a decreased responsiveness independent of the level of ventilation. These findings suggest an attenuated response to hydrophilic β2-adrenergic agonists during airway disease exacerbations associated with changes in pH. Registered at clinicaltrials.gov: NCT01216748 .

Motorcycle exhaust particles induce airway inflammation and airway hyperresponsiveness in BALB/C mice.

PubMed

Lee, Chen-Chen; Liao, Jiunn-Wang; Kang, Jaw-Jou

2004-06-01

A number of large studies have reported that environmental pollutants from fossil fuel combustion can cause deleterious effects to the immune system, resulting in an allergic reaction leading to respiratory tract damage. In this study, we investigated the effect of motorcycle exhaust particles (MEP), a major pollutant in the Taiwan urban area, on airway inflammation and airway hyperresponsiveness in laboratory animals. BALB/c mice were instilled intratracheally (i.t.) with 1.2 mg/kg and 12 mg/kg of MEP, which was collected from two-stroke motorcycle engines. The mice were exposed 3 times i.t. with MEP, and various parameters for airway inflammation and hyperresponsiveness were sequentially analyzed. We found that MEP would induce airway and pulmonary inflammation characterized by infiltration of eosinophils, neutrophils, lymphocytes, and macrophages in bronchoalveolar lavage fluid (BALF) and inflammatory cell infiltration in lung. In addition, MEP treatment enhanced BALF interleukin-4 (IL-4), IL-5, and interferon-gamma (IFN-gamma) cytokine levels and serum IgE production. Bronchial response measured by unrestrained plethysmography with methacholine challenge showed that MEP treatment induced airway hyperresponsiveness (AHR) in BALB/c mice. The chemical components in MEP were further fractionated with organic solvents, and we found that the benzene-extracted fraction exerts a similar biological effect as seen with MEP, including airway inflammation, increased BALF IL-4, serum IgE production, and induction of AHR. In conclusion, we present evidence showing that the filter-trapped particles emitted from the unleaded-gasoline-fueled two-stroke motorcycle engine may induce proinflammatory and proallergic response profiles in the absence of exposure to allergen.

In situ evaluation of density, viscosity, and thickness of adsorbed soft layers by combined surface acoustic wave and surface plasmon resonance.

PubMed

Francis, Laurent A; Friedt, Jean-Michel; Zhou, Cheng; Bertrand, Patrick

2006-06-15

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity, and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold-coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is monitored simultaneously in a single setup for the real-time and label-free measurement of the parameters of adsorbed soft layers, which means for layers with a predominant viscous behavior. A general mathematical modeling in equivalent viscoelastic transmission lines is presented to determine the correlation between experimental SAW signal shifts and the waveguide structure including the presence of the adsorbed layer and the supporting liquid from which it segregates. A methodology is presented to identify from SAW and SPR simulations the parameters representatives of the soft layer. During the absorption of a soft layer, thickness or viscosity changes are observed in the experimental ratio of the SAW signal attenuation to the SAW signal phase and are correlated with the theoretical model. As application example, the simulation method is applied to study the thermal behavior of physisorbed PNIPAAm, a polymer whose conformation is sensitive to temperature, under a cycling variation of temperature between 20 and 40 degrees C. Under the assumption of the bulk density and the bulk refractive index of PNIPAAm, thickness and viscosity of the film are obtained from simulations; the viscosity is correlated to the solvent content of the physisorbed layer.

The alveolar surface network: a new anatomy and its physiological significance.

PubMed

Scarpelli, E M

1998-08-01

It is generally held that the terminal lung unit (TLU) is an agglomeration of alveoli that opens into the branching air spaces of respiratory bronchioles, alveolar ducts, and alveolar sacs and that these structures are covered by a continuous thin liquid layer bearing a monomolecular film of surfactants at the open gas-liquid interface. The inherent structural and functional instability given TLUs by a broad liquid surface layer of this nature has been mitigated by the discovery that the TLU surface is in fact an agglomeration of bubbles, a foam (the alveolar surface network) that fills the TLU space and forms ultrathin foam films that 1) impart infrastructural stability to sustain aeration, 2) modulate circulation of surface liquid, both in series and in parallel, throughout the TLU and between TLUs and the liquid surface of conducting airways, 3) modulate surface liquid volume and exchange with interstitial liquid, and 4) sustain gas transfer between conducting airways and pulmonary capillaries throughout the respiratory cycle. The experimental evidence, from discovery to the present, is addressed in this report. Lungs were examined in thorax by stereomicroscopy immediately from the in vivo state at volumes ranging from functional residual capacity to maximal volume (Vmax). Lungs were then excised; bubble topography of all anterior and anterolateral surfaces was reaffirmed and also confirmed for all posterior and posterolateral surfaces. The following additional criteria verify the ubiquitous presence of normal intraalveolar bubbles. 1) Bubbles are absent in conducting airways. 2) Bubbles are stable and stationary in TLUs but can be moved individually by gentle microprobe pressure. 3) Adjoining bubbles move into the external medium through subpleural microincisions; there is no free gas, and vacated spaces are rendered airless. Adjacent bubbles may shift position in situ, while more distal bubbles remain stationary. 4) The position and movement of "large" bubbles

Brain-Derived Neurotrophic Factor in the Airways

PubMed Central

Prakash, Y.S.; Martin, Richard J.

2014-01-01

In addition to their well-known roles in the nervous system, there is increasing recognition that neurotrophins such as brain derived neurotrophic factor (BDNF) as well as their receptors are expressed in peripheral tissues including the lung, and can thus potentially contribute to both normal physiology and pathophysiology of several diseases. The relevance of this family of growth factors lies in emerging clinical data indicating altered neurotrophin levels and function in a range of diseases including neonatal and adult asthma, sinusitis, influenza, and lung cancer. The current review focuses on 1) the importance of BDNF expression and signaling mechanisms in early airway and lung development, critical to both normal neonatal lung function and also its disruption in prematurity and insults such as inflammation and infection; 2) how BDNF, potentially derived from airway nerves modulate neurogenic control of airway tone, a key aspect of airway reflexes as well as dysfunctional responses to allergic inflammation; 3) the emerging idea that local BDNF production by resident airway cells such as epithelium and airway smooth muscle can contribute to normal airway structure and function, and to airway hyperreactivity and remodeling in diseases such as asthma. Furthermore, given its pleiotropic effects in the airway, BDNF may be a novel and appealing therapeutic target. PMID:24560686

Sequential Stenting for Extensive Malignant Airway Stenosis

PubMed Central

Takahama, Makoto; Nakajima, Ryu; Kimura, Michitaka; Tei, Keiko; Yamamoto, Ryoji

2014-01-01

Purpose: Malignant airway stenosis extending from the bronchial bifurcation to the lower lobar orifice was treated with airway stenting. We herein examine the effectiveness of airway stenting for extensive malignant airway stenosis. Methods: Twelve patients with extensive malignant airway stenosis underwent placement of a silicone Dumon Y stent (Novatech, La Ciotat, France) at the tracheal bifurcation and a metallic Spiral Z-stent (Medico’s Hirata, Osaka, Japan) at either distal side of the Y stent. We retrospectively analyzed the therapeutic efficacy of the sequential placement of these silicone and metallic stents in these 12 patients. Results: The primary disease was lung cancer in eight patients, breast cancer in two patients, tracheal cancer in one patient, and thyroid cancer in one patient. The median survival period after airway stent placement was 46 days. The Hugh–Jones classification and performance status improved in nine patients after airway stenting. One patient had prolonged hemoptysis and died of respiratory tract hemorrhage 15 days after the treatment. Conclusion: Because the initial disease was advanced and aggressive, the prognosis after sequential airway stent placement was significantly poor. However, because respiratory distress decreased after the treatment in most patients, this treatment may be acceptable for selected patients with extensive malignant airway stenosis. PMID:25273272

Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varault, S.; Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9; Gabard, B.

We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiationmore » pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide.« less

Malignant central airway obstruction

PubMed Central

Mudambi, Lakshmi; Miller, Russell

2017-01-01

This review comprehensively describes recent advances in the management of malignant central airway obstruction (CAO). Malignant CAO can be a dramatic and devastating manifestation of primary lung cancer or metastatic disease. A variety of diagnostic modalities are available to provide valuable information to plan a therapeutic intervention. Clinical heterogeneity in the presentation of malignant CAO provides opportunities to adapt and utilize endoscopic technology and tools in many ways. Mechanical debulking, thermal tools, cryotherapy and airway stents are methods and instruments used to rapidly restore airway patency. Delayed bronchoscopic methods, such as photodynamic therapy (PDT) and brachytherapy can also be utilized in specific non-emergent situations to establish airway patency. Although data regarding the success and complications of therapeutic interventions are retrospective and characterized by clinical and outcome measure variability, the symptoms of malignant CAO can often be successfully palliated. Assessment of risks and benefits of interventions in each individual patient during the decision-making process forms the critical foundation of the management of malignant CAO. PMID:29214067

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismail, R., E-mail: rifky-mec@yahoo.com; Tauviqirrahman, M., E-mail: rifky-mec@yahoo.com; Laboratory for Surface Technology and Tribology, Faculty of Engineering Technology, University of Twente, Enschede

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boronmore » nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio‐degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser‐print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running‐in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.« less

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

NASA Astrophysics Data System (ADS)

Ismail, R.; Tauviqirrahman, M.; Jamari, Jamari; Schipper, D. J.

2009-09-01

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio-degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser-print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running-in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

Numerical simulation of soft palate movement and airflow in human upper airway by fluid-structure interaction method

NASA Astrophysics Data System (ADS)

Sun, Xiuzhen; Yu, Chi; Wang, Yuefang; Liu, Yingxi

2007-08-01

In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed three-dimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosing diseases related to anatomical structure and function of the upper airway.

Postnatal airway growth in cystic fibrosis piglets.

PubMed

Adam, Ryan J; Abou Alaiwa, Mahmoud H; Bouzek, Drake C; Cook, Daniel P; Gansemer, Nicholas D; Taft, Peter J; Powers, Linda S; Stroik, Mallory R; Hoegger, Mark J; McMenimen, James D; Hoffman, Eric A; Zabner, Joseph; Welsh, Michael J; Meyerholz, David K; Stoltz, David A

2017-09-01

Mutations in the gene encoding the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) anion channel cause CF. The leading cause of death in the CF population is lung disease. Increasing evidence suggests that in utero airway development is CFTR-dependent and that developmental abnormalities may contribute to CF lung disease. However, relatively little is known about postnatal CF airway growth, largely because such studies are limited in humans. Therefore, we examined airway growth and lung volume in a porcine model of CF. We hypothesized that CF pigs would have abnormal postnatal airway growth. To test this hypothesis, we performed CT-based airway and lung volume measurements in 3-wk-old non-CF and CF pigs. We found that 3-wk-old CF pigs had tracheas of reduced caliber and irregular shape. Their bronchial lumens were reduced in size proximally but not distally, were irregularly shaped, and had reduced distensibility. Our data suggest that lack of CFTR results in aberrant postnatal airway growth and development, which could contribute to CF lung disease pathogenesis. NEW & NOTEWORTHY This CT scan-based study of airway morphometry in the cystic fibrosis (CF) postnatal period is unique, as analogous studies in humans are greatly limited for ethical and technical reasons. Findings such as reduced airway lumen area and irregular caliber suggest that airway growth and development are CF transmembrane conductance regulator-dependent and that airway growth defects may contribute to CF lung disease pathogenesis. Copyright © 2017 the American Physiological Society.

Exploring the context of the lung proteome within the airway mucosa following allergen challenge.

PubMed

Fehniger, Thomas E; Sato-Folatre, José-Gabriel; Malmström, Johan; Berglund, Magnus; Lindberg, Claes; Brange, Charlotte; Lindberg, Henrik; Marko-Varga, György

2004-01-01

The lung proteome is a dynamic collection of specialized proteins related to pulmonary function. Many cells of different derivations, activation states, and levels of maturity contribute to the changing environment, which produces the lung proteome. Inflammatory cells reacting to environmental challenge, for example from allergens, produce and secrete proteins which have profound effects on both resident and nonresident cells located in airways, alveoli, and the vascular tree which provides blood cells to the parenchyma alveolar bed for gas exchange. In an experimental model of allergic airway inflammation, we have compared control and allergen challenged lung compartments to determine global protein expression patterns using 2D-gel electrophoresis and subsequent spot identification by MS/MS mass spectrometry. We have then specifically isolated the epithelial mucosal layer, which lines conducting airways, from control and allergen challenged lungs, using laser capture technology and performed proteome identification on these selected cell samples. A central component of our investigations has been to contextually relate the histological features of the dynamic pulmonary environment to the changes in protein expression observed following challenge. Our results provide new information of the complexity of the submucosa/epithelium interface and the mechanisms behind the transformation of airway epithelium from normal steady states to functionally activated states.

Surface properties of Mars' polar layered deposits and polar landing sites

USGS Publications Warehouse

Vasavada, Ashwin R.; Williams, Jean-Pierre; Paige, David A.; Herkenhoff, Ken E.; Bridges, Nathan T.; Greeley, Ronald; Murray, Bruce C.; Bass, Deborah S.; McBride, Karen S.

2000-01-01

On December 3, 1999, the Mars Polar Lander and Mars Microprobes will land on the planet's south polar layered deposits near (76°S, 195°W) and conduct the first in situ studies of the planet's polar regions. The scientific goals of these missions address several poorly understood and globally significant issues, such as polar meteorology, the composition and volatile content of the layered deposits, the erosional state and mass balance of their surface, their possible relationship to climate cycles, and the nature of bright and dark aeolian material. Derived thermal inertias of the southern layered deposits are very low (50-100 J m-2 s-1/2 K-1), suggesting that the surface down to a depth of a few centimeters is generally fine grained or porous and free of an appreciable amount of rock or ice. The landing site region is smoother than typical cratered terrain on ∼1 km pixel-1 Viking Orbiter images but contains low-relief texture on ∼5 to 100 m pixel-1 Mariner 9 and Mars Global Surveyor images. The surface of the southern deposits is older than that of the northern deposits and appears to be modified by aeolian erosion or ablation of ground ice.

Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification.

PubMed

Lassnig, R; Hollerer, M; Striedinger, B; Fian, A; Stadlober, B; Winkler, A

2015-11-01

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p ++ -silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification

PubMed Central

Lassnig, R.; Hollerer, M.; Striedinger, B.; Fian, A.; Stadlober, B.; Winkler, A.

2015-01-01

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p++-silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3–4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact–channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility. PMID:26543442

Deformation characteristics of the near-surface layers of zirconia ceramics implanted with aluminum ions

NASA Astrophysics Data System (ADS)

Ghyngazov, S. A.; Vasiliev, I. P.; Frangulyan, T. S.; Chernyavski, A. V.

2015-10-01

The effect of ion treatment on the phase composition and mechanical properties of the near-surface layers of zirconium ceramic composition 97 ZrO2-3Y2O3 (mol%) was studied. Irradiation of the samples was carried out by accelerated ions of aluminum with using vacuum-arc source Mevva 5-Ru. Ion beam had the following parameters: the energy of the accelerated ions E = 78 keV, the pulse current density Ji = 4mA / cm2, current pulse duration equal τ = 250 mcs, pulse repetition frequency f = 5 Hz. Exposure doses (fluence) were 1016 и 1017 ion/cm2. The depth distribution implanted ions was studied by SIMS method. It is shown that the maximum projected range of the implanted ions is equal to 250 nm. Near-surface layers were investigated by X-ray diffraction (XRD) at fixed glancing incidence angle. It is shown that implantation of aluminum ions into the ceramics does not lead to a change in the phase composition of the near-surface layer. The influence of implanted ions on mechanical properties of ceramic near-surface layers was studied by the method of dynamic nanoindentation using small loads on the indenter P=300 mN. It is shown that in ion- implanted ceramic layer the processes of material recovery in the deformed region in the unloading mode proceeds with higher efficiency as compared with the initial material state. The deformation characteristics of samples before and after ion treatment have been determined from interpretation of the resulting P-h curves within the loading and unloading sections by the technique proposed by Oliver and Pharr. It was found that implantation of aluminum ions in the near-surface layer of zirconia ceramics increases nanohardness and reduces the Young's modulus.

Surface Layer turbulence profiling with the SL-SLODAR and LUSCI at ESO Paranal Observatory

NASA Astrophysics Data System (ADS)

Lombardi, G.; Sarazin, M.; Char, F.; González Ávila, C.; Navarrete, J.; Tokovinin, A.; Wilson, R. W.; Butterley, T.

2014-10-01

In the context of the Surface Layer investigation at ESO Paranal Observatory, a Surface Layer Slope Detection And Ranging (SL-SLODAR) instrument prototype has been used at Paranal during 2012, while Lunar Scintillometer (LuSci) measurements campaigns are being carried out since 2008. Simultaneous Surface Layer profiling data from the two instruments are analysed in order to compare the two instruments to enforce their reliability and finely characterize the Paranal Surface Layer profile. BETA is the slope of the turbulence power spectrum delivered by the SL-SLODAR. It is intended purely as a diagnostic tool to indicate whether the Cn2 profile can be trusted. When BETA is significantly less than 3.667 (Kolmogorov law value) this generally indicates that the wind speed is low and the data sets are too short to fully sample the low frequency components of the turbulence. Around the Kolmogorov value, the integrals form the SL-SLODAR and LuSci are pretty much the same. This is valid also in the first 20 m above ground only (SL). Both instruments agree very well when the wind speed on the Paranal platform is higher than 3 m/s. This last result suggests that wind speed higher than 3 m/s allow to have more reliable turbulence profile measurements from both instruments for further analyses of the Surface Layer. Furthermore, the disagreement of the two instruments in connection with wind speed lower than 3 m/s also suggests that the wind speed is a critical parameter to be taken into account before the treatment of the data.

Growing season boundary layer climate and surface exchanges in a subarctic lichen woodland

NASA Technical Reports Server (NTRS)

Fitzjarrald, David R.; Moore, Kathleen E.

1994-01-01

Between June and August 1990, observations were made at two surface micrometeorological towers near Schefferville Quebec (54 deg 52 min N, 66 deg 40.5 min W), one in a fen and one in the subarctic lichen woodland, and at four surface climatological stations. Data from these surface stations were supplemented by regular radiosonde launches. Supporting measurements of radiative components and soil temperatures allowed heat and moisture balances to be obtained at two sites. The overall surface meteorological experiment design and results of micrometeorological observations made on a 30-m tower in the lichen woodland are presented here. Seasonal variation in the heat and water vapor transport characteristics illustrate the marked effect of the late summer climatological shift in air mass type. During the first half of the summer, average valley sidewalls only 100 m high are sufficient to channel winds along the valley in the entire convective boundary layer. Channeling effects at the surface, known for some time at the long-term climate station in Schefferville, are observed both at ridge top and in the valley, possibly the response of the flow to the NW-SE orientation of valleys in the region. Diurnal surface temperature amplitude at ridge top (approximately equal to 10 C) was found to be half that observed in the valley. Relatively large differences in precipitation among these stations and the climatological station at Schefferville airport were observed and attributed to the local topography. Eddy correlation observations of the heat, moisture and momentum transports were obtained from a 30-m tower above a sparse (approximately equal to 616 stems/ha) black spruce lichen woodland. Properties of the turbulent surface boundary layer agree well with previous wind tunnel studies over idealized rough surfaces. Daytime Bowen ratios of 2.5-3 are larger than those reported in previous studies. Surface layer flux data quality was assessed by looking at the surface layer heat

Intrathoracic airway measurement: ex-vivo validation

NASA Astrophysics Data System (ADS)

Reinhardt, Joseph M.; Raab, Stephen A.; D'Souza, Neil D.; Hoffman, Eric A.

1997-05-01

High-resolution x-ray CT (HRCT) provides detailed images of the lungs and bronchial tree. HRCT-based imaging and quantitation of peripheral bronchial airway geometry provides a valuable tool for assessing regional airway physiology. Such measurements have been sued to address physiological questions related to the mechanics of airway collapse in sleep apnea, the measurement of airway response to broncho-constriction agents, and to evaluate and track the progression of disease affecting the airways, such as asthma and cystic fibrosis. Significant attention has been paid to the measurements of extra- and intra-thoracic airways in 2D sections from volumetric x-ray CT. A variety of manual and semi-automatic techniques have been proposed for airway geometry measurement, including the use of standardized display window and level settings for caliper measurements, methods based on manual or semi-automatic border tracing, and more objective, quantitative approaches such as the use of the 'half-max' criteria. A recently proposed measurements technique uses a model-based deconvolution to estimate the location of the inner and outer airway walls. Validation using a plexiglass phantom indicates that the model-based method is more accurate than the half-max approach for thin-walled structures. In vivo validation of these airway measurement techniques is difficult because of the problems in identifying a reliable measurement 'gold standard.' In this paper we report on ex vivo validation of the half-max and model-based methods using an excised pig lung. The lung is sliced into thin sections of tissue and scanned using an electron beam CT scanner. Airways of interest are measured from the CT images, and also measured with using a microscope and micrometer to obtain a measurement gold standard. The result show no significant difference between the model-based measurements and the gold standard; while the half-max estimates exhibited a measurement bias and were significantly

In vivo measurement of skin surface strain and sub-surface layer deformation induced by natural tissue stretching.

PubMed

Maiti, Raman; Gerhardt, Lutz-Christian; Lee, Zing S; Byers, Robert A; Woods, Daniel; Sanz-Herrera, José A; Franklin, Steve E; Lewis, Roger; Matcher, Stephen J; Carré, Matthew J

2016-09-01

Stratum corneum and epidermal layers change in terms of thickness and roughness with gender, age and anatomical site. Knowledge of the mechanical and tribological properties of skin associated with these structural changes are needed to aid in the design of exoskeletons, prostheses, orthotics, body mounted sensors used for kinematics measurements and in optimum use of wearable on-body devices. In this case study, optical coherence tomography (OCT) and digital image correlation (DIC) were combined to determine skin surface strain and sub-surface deformation behaviour of the volar forearm due to natural tissue stretching. The thickness of the epidermis together with geometry changes of the dermal-epidermal junction boundary were calculated during change in the arm angle, from flexion (90°) to full extension (180°). This posture change caused an increase in skin surface Lagrange strain, typically by 25% which induced considerable morphological changes in the upper skin layers evidenced by reduction of epidermal layer thickness (20%), flattening of the dermal-epidermal junction undulation (45-50% reduction of flatness being expressed as Ra and Rz roughness profile height change) and reduction of skin surface roughness Ra and Rz (40-50%). The newly developed method, DIC combined with OCT imaging, is a powerful, fast and non-invasive methodology to study structural skin changes in real time and the tissue response provoked by mechanical loading or stretching. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Development and Application of Airway Devices in China

PubMed Central

Chen, Xiangdong; Ma, Wuhua; Liu, Renyu; Yao, Shanglong

2017-01-01

Airway management is one of the most important tasks for anesthesiologists. Anesthesiologists are experts in airway management and have made tremendous contribution to the development of the airway devices. Chinese anesthesiologists have made significant contribution in introducing advanced airway management and developing innovative techniques and devices for airway management in China. This article overviews the development and application of airway devices in China as well as the dedication and contribution of Chinese experts in the development of novel airway devices. With the development of science and technology accompanied by the advanced knowledge in airway management, more effective and safe artificial airways will be developed for clinical practice. The authors believe that Chinese experts will continue their outstanding contribution to the development of innovative airway devices, systems and knowledge. PMID:28191485

Airway smooth muscle responsiveness from dogs with airway hyperresponsiveness after O/sub 3/ inhalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, G.L.; O'Byrne, P.M.; Pashley, M.

1988-07-01

Airway hyperresponsiveness occurs after inhalation of O3 in dogs. The purpose of this study was to examine the responsiveness of trachealis smooth muscle in vitro to electrical field stimulation, exogenous acetylcholine, and potassium chloride from dogs with airway hyperresponsiveness after inhaled O3 in vivo and to compare this with the responsiveness of trachealis muscle from control dogs. In addition, excitatory junction potentials were measured with the use of single and double sucrose gap techniques in both groups of dogs to determine whether inhaled O3 affects the release of acetylcholine from parasympathetic nerves in trachealis muscle. Airway hyperresponsiveness developed in allmore » dogs after inhaled O3 (3 ppm for 30 min). The acetylcholine provocative concentration decreased from 4.11 mg/ml before O3 inhalation to 0.66 mg/ml after O3 (P less than 0.0001). The acetylcholine provocative concentration increased slightly after control inhalation of dry room air. Airway smooth muscle showed increased responses to both electrical field stimulation and exogenous acetylcholine but not to potassium chloride in preparations from dogs with airway hyperresponsiveness in vivo. The increased response to electrical field stimulation was not associated with a change in excitatory junctional potentials. These results suggest that a postjunctional alteration in trachealis muscle function occurs after inhaled O3 in dogs, which may account for airway hyperresponsiveness after O3 in vivo.« less

Alcohol and Airways Function in Health and Disease

PubMed Central

Sisson, Joseph H.

2007-01-01

The volatility of alcohol promotes the movement of alcohol from the bronchial circulation across the airway epithelium and into the conducting airways of the lung. The exposure of the airways through this route likely accounts for many of the biologic effects of alcohol on lung airway functions. The impact of alcohol on lung airway functions is dependent on the concentration, duration and route of exposure. Brief exposure to mild concentrations of alcohol may enhance mucociliary clearance, stimulates bronchodilation and probably attenuates the airway inflammation and injury observed in asthma and COPD. Prolonged and heavy exposure to alcohol impairs mucociliary clearance, may complicate asthma management and likely worsens outcomes including lung function and mortality in COPD patients. Non-alcohol congeners and alcohol metabolites act as triggers for airway disease exacerbations especially in atopic asthmatics and in Asian populations who have a reduced capacity to metabolize alcohol. Research focused on the mechanisms of alcohol-mediated changes in airway functions has identified specific mechanisms that mediate alcohol effects within the lung airways. These include prominent roles for the second messengers calcium and nitric oxide, regulatory kinases including PKG and PKA, alcohol and acetaldehyde-metabolizing enzymes such as aldehyde dehydrogenase type 2 (ALDH2). The role alcohol may play in the pathobiology of airway mucus, bronchial blood flow, airway smooth muscle regulation and the interaction with other airway exposure agents, such as cigarette smoke, represent opportunities for future investigation. PMID:17764883

Alcohol and airways function in health and disease.

PubMed

Sisson, Joseph H

2007-08-01

The volatility of alcohol promotes the movement of alcohol from the bronchial circulation across the airway epithelium and into the conducting airways of the lung. The exposure of the airways through this route likely accounts for many of the biologic effects of alcohol on lung airway functions. The effect of alcohol on lung airway functions is dependent on the concentration, duration, and route of exposure. Brief exposure to mild concentrations of alcohol may enhance mucociliary clearance, stimulates bronchodilation, and probably attenuates the airway inflammation and injury observed in asthma and chronic obstructive pulmonary disease (COPD). Prolonged and heavy exposure to alcohol impairs mucociliary clearance, may complicate asthma management, and likely worsens outcomes including lung function and mortality in COPD patients. Nonalcohol congeners and alcohol metabolites act as triggers for airway disease exacerbations especially in atopic asthmatics and in Asian populations who have a reduced capacity to metabolize alcohol. Research focused on the mechanisms of alcohol-mediated changes in airway functions has identified specific mechanisms that mediate alcohol effects within the lung airways. These include prominent roles for the second messengers calcium and nitric oxide, regulatory kinases including PKG and PKA, alcohol- and acetaldehyde-metabolizing enzymes such as aldehyde dehydrogenase 2. The role alcohol may play in the pathobiology of airway mucus, bronchial blood flow, airway smooth muscle regulation, and the interaction with other airway exposure agents, such as cigarette smoke, represents opportunities for future investigation.

Surface morphology and structure of Ge layer on Si(111) after solid phase epitaxy

NASA Astrophysics Data System (ADS)

Yoshida, Ryoma; Tosaka, Aki; Shigeta, Yukichi

2018-05-01

The surface morphology change of a Ge layer on a Si(111) surface formed by solid phase epitaxy has been investigated with a scanning tunneling microscope (STM). The Ge film was deposited at room temperature and annealed at 400 °C or 600 °C. The STM images of the sample surface after annealing at 400 °C show a flat wetting layer (WL) with small three-dimensional islands on the WL. After annealing at 600 °C, the STM images show a surface roughening with large islands. From the relation between the average height of the roughness and the deposited layer thickness, it is confirmed that the diffusion of Ge atoms becomes very active at 600 °C. The Si crystal at the interface is reconstructed and the intermixing occurs over 600 °C. However, the intermixing is fairly restricted in the solid phase epitaxy growth at 400 °C. The surface morphology changes with the crystallization at 400 °C are discussed by the shape of the islands formed on the WL surface. It is shown that the diffusion of the Ge atoms in the amorphous phase is active even at 400 °C.

Electrokinetic flow in a capillary with a charge-regulating surface polymer layer.

PubMed

Keh, Huan J; Ding, Jau M

2003-07-15

An analytical study of the steady electrokinetic flow in a long uniform capillary tube or slit is presented. The inside wall of the capillary is covered by a layer of adsorbed or covalently bound charge-regulating polymer in equilibrium with the ambient electrolyte solution. In this solvent-permeable and ion-penetrable surface polyelectrolyte layer, ionogenic functional groups and frictional segments are assumed to distribute at uniform densities. The electrical potential and space charge density distributions in the cross section of the capillary are obtained by solving the linearized Poisson-Boltzmann equation. The fluid velocity profile due to the application of an electric field and a pressure gradient through the capillary is obtained from the analytical solution of a modified Navier-Stokes/Brinkman equation. Explicit formulas for the electroosmotic velocity, the average fluid velocity and electric current density on the cross section, and the streaming potential in the capillary are also derived. The results demonstrate that the direction of the electroosmotic flow and the magnitudes of the fluid velocity and electric current density are dominated by the fixed charge density inside the surface polymer layer, which is determined by the regulation characteristics such as the dissociation equilibrium constants of the ionogenic functional groups in the surface layer and the concentration of the potential-determining ions in the bulk solution.

Enhancing the mechanical and biological performance of a metallic biomaterial for orthopedic applications through changes in the surface oxide layer by nanocrystalline surface modification.

PubMed

Bahl, Sumit; Shreyas, P; Trishul, M A; Suwas, Satyam; Chatterjee, Kaushik

2015-05-07

Nanostructured metals are a promising class of biomaterials for application in orthopedics to improve the mechanical performance and biological response for increasing the life of biomedical implants. Surface mechanical attrition treatment (SMAT) is an efficient way of engineering nanocrystalline surfaces on metal substrates. In this work, 316L stainless steel (SS), a widely used orthopedic biomaterial, was subjected to SMAT to generate a nanocrystalline surface. Surface nanocrystallization modified the nature of the oxide layer present on the surface. It increased the corrosion-fatigue strength in saline by 50%. This increase in strength is attributed to a thicker oxide layer, residual compressive stresses, high strength of the surface layer, and lower propensity for intergranular corrosion in the nanocrystalline layer. Nanocrystallization also enhanced osteoblast attachment and proliferation. Intriguingly, wettability and surface roughness, the key parameters widely acknowledged for controlling the cellular response remained unchanged after nanocrystallization. The observed cellular behavior is explained in terms of the changes in electronic properties of the semiconducting passive oxide film present on the surface of 316L SS. Nanocrystallization increased the charge carrier density of the n-type oxide film likely preventing denaturation of the adsorbed cell-adhesive proteins such as fibronectin. In addition, a net positive charge developed on the otherwise neutral oxide layer, which is known to facilitate cellular adhesion. The role of changes in the electronic properties of the oxide films on metal substrates is thus highlighted in this work. This study demonstrates the advantages of nanocrystalline surface modification by SMAT for processing metallic biomaterials used in orthopedic implants.

Formation of porous surface layers in reaction bonded silicon nitride during processing

NASA Technical Reports Server (NTRS)

Shaw, N. J.; Glasgow, T. K.

1979-01-01

An effort was undertaken to determine if the formation of the generally observed layer of large porosity adjacent to the as-nitride surfaces of reaction bonded silicon nitrides could be prevented during processing. Isostatically pressed test bars were prepared from wet vibratory milled Si powder. Sintering and nitriding were each done under three different conditions:(1) bars directly exposed to the furnance atmosphere; (2) bars packed in Si powder; (3) bars packed in Si3N4 powder. Packing the bars in either Si of Si3N4 powder during sintering retarded formation of the layer of large porosity. Only packing the bars in Si prevented formation of the layer during nitridation. The strongest bars (316 MPa) were those sintered in Si and nitrided in Si3N4 despite their having a layer of large surface porosity; failure initiated at very large pores and inclusions. The alpha/beta ratio was found to be directly proportional to the oxygen content; a possible explanation for this relationship is discussed.

Double layer of platinum electrodes: Non-monotonic surface charging phenomena and negative double layer capacitance

NASA Astrophysics Data System (ADS)

Huang, Jun; Zhou, Tao; Zhang, Jianbo; Eikerling, Michael

2018-01-01

In this study, a refined double layer model of platinum electrodes accounting for chemisorbed oxygen species, oriented interfacial water molecules, and ion size effects in solution is presented. It results in a non-monotonic surface charging relation and a peculiar capacitance vs. potential curve with a maximum and possibly negative values in the potential regime of oxide-formation.

LDV measurement of boundary layer on rotating blade surface in wind tunnel

NASA Astrophysics Data System (ADS)

Maeda, Takao; Kamada, Yasunari; Murata, Junsuke; Suzuki, Daiki; Kaga, Norimitsu; Kagisaki, Yosuke

2014-12-01

Wind turbines generate electricity due to extracting energy from the wind. The rotor aerodynamics strongly depends on the flow around blade. The surface flow on the rotating blade affects the sectional performance. The wind turbine surface flow has span-wise component due to span-wise change of airfoil section, chord length, twisted angle of blade and centrifugal force on the flow. These span-wise flow changes the boundary layer on the rotating blade and the sectional performance. Hence, the thorough understanding of blade surface flow is important to improve the rotor performance. For the purpose of clarification of the flow behaviour around the rotor blade, the velocity in the boundary layer on rotating blade surface of an experimental HAWT was measured in a wind tunnel. The velocity measurement on the blade surface was carried out by a laser Doppler velocimeter (LDV). As the results of the measurement, characteristics of surface flow are clarified. In optimum tip speed operation, the surface flow on leading edge and r/R=0.3 have large span-wise velocity which reaches 20% of sectional inflow velocity. The surface flow inboard have three dimensional flow patterns. On the other hand, the flow outboard is almost two dimensional in cross sectional plane.

EFFECTS OF TITANIUM DIOXIDE NANOPARTICLE EXPOSURE ON NEUROIMMUNE RESPONSES IN RAT AIRWAYS

PubMed Central

Scuri, Mario; Chen, Bean T.; Castranova, Vincent; Reynolds, Jeffrey S.; Johnson, Victor J.; Samsell, Lennie; Walton, Cheryl; Piedimonte, Giovanni

2013-01-01

Exposure to ambient nanoparticles (defined as particulate matter [PM] having one dimension < 100 nm) is associated with increased risk of childhood and adult asthma. Nanomaterials feature a smaller aerodynamic diameter and a higher surface area per unit mass ratio compared to fine or coarse-sized particles, resulting in greater lung deposition efficiency and an increased potential for biological interaction. The neurotrophins nerve growth factor and brain-derived neurotrophic factor are key regulatory elements of neuronal development and responsiveness of airway sensory neurons. Changes in their expression are associated with bronchoconstriction, airway hyperresponsiveness, and airway inflammation. The neurogenic-mediated control of airway responses is a key pathophysiological mechanism of childhood asthma. However, the effects of nanoparticle exposure on neurotrophin-driven airway responses and their potential role as a predisposing factor for developing asthma have not been clearly elucidated. In this study, in vivo inhalation exposure to titanium dioxide nanoparticles (12 mg/m13; 5.6 h/d for 3 d) produced upregulation of lung neurotrophins in weanling (2-wk-old) and newborn (2-d-old) rats but not in adult (12-wk-old) animals compared to controls. This effect was associated with increased airway responsiveness and upregulation of growth-related oncogene/keratine-derived chemokine (GRO/KC; CXCL1, rat equivalent of human interleukin [IL]-8) in bronchoalveolar lavage fluid. These data show for the first time that exposure to nanoparticulate upregulates the expression of lung neurotrophins in an age-dependent fashion and that this effect is associated with airway hyperresponsiveness and inflammation. These results suggest the presence of a critical window of vulnerability in earlier stages of lung development, which may lead to a higher risk of developing asthma. PMID:20818535

Surface modification of silk fibroin fabric using layer-by-layer polyelectrolyte deposition and heparin immobilization for small-diameter vascular prostheses.

PubMed

Elahi, M Fazley; Guan, Guoping; Wang, Lu; Zhao, Xinzhe; Wang, Fujun; King, Martin W

2015-03-03

There is an urgent need to develop a biologically active implantable small-diameter vascular prosthesis with long-term patency. Silk-fibroin-based small-diameter vascular prosthesis is a promising candidate having higher patency rate; however, the surface modification is indeed required to improve its further hemocompatibility. In this study, silk fibroin fabric was modified by a two-stage process. First, the surface of silk fibroin fabric was coated using a layer-by-layer polyelectrolyte deposition technique by stepwise dipping the silk fibroin fabric into a solution of cationic poly(allylamine hydrochloride) (PAH) and anionic poly(acrylic acid) (PAA) solution. The dipping procedure was repeated to obtain the PAH/PAA multilayers deposited on the silk fibroin fabrics. Second, the polyelectrolyte-deposited silk fibroin fabrics were treated in EDC/NHS-activated low-molecular-weight heparin (LMWH) solution at 4 °C for 24 h, resulting in immobilization of LMWH on the silk fibroin fabrics surface. Scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray data revealed the accomplishment of LMWH immobilization on the polyelectrolyte-deposited silk fibroin fabric surface. The higher the number of PAH/PAA coating layers on the silk fibroin fabric, the more surface hydrophilicity could be obtained, resulting in a higher fetal bovine serum protein and platelets adhesion resistance properties when tested in vitro. In addition, compared with untreated sample, the surface-modified silk fibroin fabrics showed negligible loss of bursting strength and thus reveal the acceptability of polyelectrolytes deposition and heparin immobilization approach for silk-fibroin-based small-diameter vascular prostheses modification.

Anatomic and physiopathologic changes affecting the airway of the elderly patient: implications for geriatric-focused airway management

PubMed Central

Johnson, Kathleen N; Botros, Daniel B; Groban, Leanne; Bryan, Yvon F

2015-01-01

There are many anatomical, physiopathological, and cognitive changes that occur in the elderly that affect different components of airway management: intubation, ventilation, oxygenation, and risk of aspiration. Anatomical changes occur in different areas of the airway from the oral cavity to the larynx. Common changes to the airway include tooth decay, oropharyngeal tumors, and significant decreases in neck range of motion. These changes may make intubation challenging by making it difficult to visualize the vocal cords and/or place the endotracheal tube. Also, some of these changes, including but not limited to, atrophy of the muscles around the lips and an edentulous mouth, affect bag mask ventilation due to a difficult face-mask seal. Physiopathologic changes may impact airway management as well. Common pulmonary issues in the elderly (eg, obstructive sleep apnea and COPD) increase the risk of an oxygen desaturation event, while gastrointestinal issues (eg, achalasia and gastroesophageal reflux disease) increase the risk of aspiration. Finally, cognitive changes (eg, dementia) not often seen as related to airway management may affect patient cooperation, especially if an awake intubation is required. Overall, degradation of the airway along with other physiopathologic and cognitive changes makes the elderly population more prone to complications related to airway management. When deciding which airway devices and techniques to use for intubation, the clinician should also consider the difficulty associated with ventilating the patient, the patient’s risk of oxygen desaturation, and/or aspiration. For patients who may be difficult to bag mask ventilate or who have a risk of aspiration, a specialized supralaryngeal device may be preferable over bag mask for ventilation. Patients with tumors or decreased neck range of motion may require a device with more finesse and maneuverability, such as a flexible fiberoptic broncho-scope. Overall, geriatric-focused airway

The Difficult Airway Society 'ADEPT' guidance on selecting airway devices: the basis of a strategy for equipment evaluation.

PubMed

Pandit, J J; Popat, M T; Cook, T M; Wilkes, A R; Groom, P; Cooke, H; Kapila, A; O'Sullivan, E

2011-08-01

Faced with the concern that an increasing number of airway management devices were being introduced into clinical practice with little or no prior evidence of their clinical efficacy or safety, the Difficult Airway Society formed a working party (Airway Device Evaluation Project Team) to establish a process by which the airway management community within the profession could itself lead a process of formal device/equipment evaluation. Although there are several national and international regulations governing which products can come on to the market and be legitimately sold, there has hitherto been no formal professional guidance relating to how products should be selected (i.e. purchased). The Airway Device Evaluation Project Team's first task was to formulate such advice, emphasising evidence-based principles. Team discussions led to a definition of the minimum level of evidence needed to make a pragmatic decision about the purchase or selection of an airway device. The Team concluded that this definition should form the basis of a professional standard, guiding those with responsibility for selecting airway devices. We describe how widespread adoption of this professional standard can act as a driver to create an infrastructure in which the required evidence can be obtained. Essential elements are that: (i) the Difficult Airway Society facilitates a coherent national network of research-active units; and (ii) individual anaesthetists in hospital trusts play a more active role in local purchasing decisions, applying the relevant evidence and communicating their purchasing decisions to the Difficult Airway Society. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

Magnetic field-related heating instabilities in the surface layers of the sun and stars

NASA Technical Reports Server (NTRS)

Ferrari, A.; Rosner, R.; Vaiana, G. S.

1982-01-01

The stability of a magnetized low-density plasma to current-driven filamentation instabilities is investigated and the results are applied to the surface layers of stars. Unlike previous studies, the initial (i.e., precoronal) state of the stellar surface atmosphere is taken to be a low-density, optically thin magnetized plasma in radiative equilibrium. The linear analysis shows that the surface layers of main-sequence stars (including the sun) which are threaded by magnetic fields are unstable; the instabilities considered lead to structuring perpendicular to the ambient magnetic fields. These results suggest that relatively modest surface motions, in conjunction with the presence of magnetic fields, suffice to account for the presence of inhomogeneous chromospheric and coronal plasma overlying a star's surface.

Lesion dehydration rate changes with the surface layer thickness during enamel remineralization

NASA Astrophysics Data System (ADS)

Chang, Nai-Yuan N.; Jew, Jamison M.; Fried, Daniel

2018-02-01

A transparent highly mineralized outer surface zone is formed on caries lesions during remineralization that reduces the permeability to water and plaque generated acids. However, it has not been established how thick the surface zone should be to inhibit the penetration of these fluids. Near-IR (NIR) reflectance coupled with dehydration can be used to measure changes in the fluid permeability of lesions in enamel and dentin. Based on our previous studies, we postulate that there is a strong correlation between the surface layer thickness and the rate of dehydration. In this study, the rates of dehydration for simulated lesions in enamel with varying remineralization durations were measured. Reflectance imaging at NIR wavelengths from 1400-2300 nm, which coincides with higher water absorption and manifests the greatest sensitivity to contrast changes during dehydration measurements, was used to image simulated enamel lesions. The results suggest that the relationship between surface zone thickness and lesion permeability is highly non-linear, and that a small increase in the surface layer thickness may lead to a significant decrease in permeability.

Intercomparison of 7 Planetary Boundary-Layer/Surface-Layer Physics Schemes over Complex Terrain for Battlefield Situational Awareness

DTIC Science & Technology

This study considers the performance of 7 of the Weather Research and Forecast model boundary-layer (BL) parameterization schemes in a complex...schemes performed best. The surface parameters, planetary BL structure, and vertical profiles are important for US Army Research Laboratory

Use of optical coherence tomography in delineating airways microstructure: comparison of OCT images to histopathological sections