scholarly journals Polydisperse Aerosol Transport and Deposition in Upper Airways of Age-Specific Lung

Author(s):  
Mohammad S. Islam ◽  
Puchanee Larpruenrudee ◽  
Sheikh I. Hossain ◽  
Mohammad Rahimi-Gorji ◽  
Yuantong Gu ◽  
...  

A comprehensive understanding of airflow characteristics and particle transport in the human lung can be useful in modelling to inform clinical diagnosis, treatment, and management, including prescription medication and risk assessment for rehabilitation. One of the difficulties in clinical treatment of lung disorders lies in the patients’ variable physical lung characteristics caused by age, amongst other factors, such as different lung sizes. A precise understanding of the comparison between different age groups with various flow rates is missing in the literature, and this study aims to analyse the airflow and aerosol transport within the age-specific lung. ANSYS Fluent solver and the large-eddy simulation (LES) model were employed for the numerical simulation. The numerical model was validated with the available literature and the computational results showed airway size-reduction significantly affected airflow and particle transport in the upper airways. This study reports higher deposition at the mouth-throat region for larger diameter particles. The overall deposition efficiency (DE) increased with airway size reduction and flow rate. Lung aging effected the pressure distribution and a higher pressure drop was reported for the aged lung as compared to the younger lung. These findings could inform medical management through individualised simulation of drug-aerosol delivery processes for the patient-specific lung.

Author(s):  
Parth Singh ◽  
Vishnu Raghav ◽  
Vignesh Padhmashali ◽  
Gunther Paul ◽  
Mohammad S. Islam ◽  
...  

Airflow and particle transport in the human lung system is influenced by biological and other factors such as breathing pattern, particle properties, and deposition mechanisms. Most of the studies to date have analyzed airflow characterization and aerosol transport in idealized and realistic models. Precise airflow characterization for airway stenosis in a digital reference model is lacking in the literature. This study presents a numerical simulation of airflow and particle transport through a stenosis section of the airway. A realistic CT-scan-based mouth–throat and upper airway model was used for the numerical calculations. Three different models of a healthy lung and of airway stenosis of the left and right lung were used for the calculations. The ANSYS FLUENT solver, based on the finite volume discretization technique, was used as a numerical tool. Proper grid refinement and validation were performed. The numerical results show a complex-velocity flow field for airway stenosis, where airflow velocity magnitude at the stenosis section was found to be higher than that in healthy airways. Pressure drops at the mouth–throat and in the upper airways show a nonlinear trend. Comprehensive pressure analysis of stenosis airways would increase our knowledge of the safe mechanical ventilation of the lung. The turbulence intensities at the stenosis sections of the right and left lung were found to be different. Deposition efficiency (DE) increased with flow rate and particle size. The findings of the present study increase our understanding of airflow patterns in airway stenosis under various disease conditions. More comprehensive stenosis analysis is required to further improve knowledge of the field.


Author(s):  
Jim S. Chen ◽  
Jinho Kim

The hazard caused by inhaled particles depends on the site at which they deposit within the respiratory system. Knowledge of respiratory aerosol deposition rates and locations is necessary to (1) evaluate potential health effects and establish critical exposure limits and (2) design effective inhaled medications that target specific lung regions. Particles smaller than 10 μm in diameter can be breathed into lungs and are known as inhalable particles, while most of larger particles settle in mouth and nose. Inhalable particles settle in different regions of the lungs and the settling regions depends on the particle size. The motion of a particle is mainly affected by the inertia of the particle and by the particle’s aerodynamic drag. The most important dimensionless parameters in the prediction of particle motion are the flow Reynolds number and the Stoke number, which combines the effects of particle diameter, particle density, shape factor and slip factor. The purpose of this study is to investigate the airflows in human respiratory airways. The influence of particle size on transport and deposition patterns in the 3-D lung model of the human airways is the primary concern of this research. The lung model developed for this research extends from the trachea to the segmental bronchi and it is based on Weibel’s model. The velocity field of air is studied and particle transport and deposition are compared for particles in the diameter range of 1 μm – 100 μm (G0 to G2) and 0.1 μm – 10 μm (G3 to G5) at airflow rates of 6.0, 16.7, and 30.0 L/min, which represent breathing at rest, light activity, and heavy activity, respectively. The investigation is carried out by computational fluid dynamics (CFD) using the software Fluent 6.2. Three-dimensional, steady, incompressible, laminar flow is simulated to obtain the flow field. The discrete phase model (DPM) is then employed to predict the particle trajectories and the deposition efficiency by considering drag and gravity forces. In the present study, the Reynolds number in the range of 200 – 2000 and the Stoke number in the range of 10−5 – 0.12 are investigated. For particle size over 10 μm, deposition mainly occurs by inertial impaction, where deposition generally increases with increases in particle size and flow rate. Most of the larger micron sized particles are captured at the bifurcations, while submicron sized particles flow with the fluid into the lung lower airways. The trajectories of submicron sized particles are strongly influenced by the secondary flow in daughter branches. The present results of particle deposition efficiency in the human upper airways compared well with data in the literature.


Author(s):  
Tatyana A. Brusentseva ◽  
◽  
Vladislav S. Shikalov ◽  
Sergei M. Lavruk ◽  
Vasily M. Fomin

The work is devoted to the deposition of composite powder materials by cold spray method. As a spraying material, a thermoplastic compound «WAY» for marking the roadway was used. An asphalt concrete was used as a substrate. As a result of experimental studies, the dependence of the deposition efficiency on the stagnation temperature of the working air in the ejector nozzle was obtained. The ANSYS Fluent package was used for evaluative modeling of the cold spraying process. Gas flow patterns were obtained in the computational domain without particles and taking into account the interaction of the flow with particles. The trajectory of the particles was calculated for various spraying parameters


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 1-1
Author(s):  
Dawood Findakly

Leukemia cutis (LC) is a rare cutaneous infiltration of extramedullary neoplastic hematopoietic cells with a paucity of data on their management, given that most cases are from individual case reports or case series, which further impact outcomes. This review aims to investigate the clinical characteristics of LC and highlight our cytogenetic findings that could contribute to our growing understanding and help reshape the prognosis of this rare but deadly condition. Patients and methods PubMed, Medline, ScienceDirect, and Scopus databases searched for "Leukemia Cutis" case reports from January 2000 to July 2020 pooled with a case from our institution. Results We included 184 biopsy-proven LC cases. Male: female ratio was 1.49:1. Mean age at diagnosis (± SD) was 48.9 (±25.9) years. Regarding age groups, 17 (9.2%), 16 (8.7%), 14 (7.6%), 12 (6.5%), 16 (8.7%), 29 (15.8%), and 80 (43.5%) patients were noted in the age groups of <1, 1-19, 19-30, 31-40, 41-50, 51-60, and >60 years, respectively. The demographics and clinical features of LC are summarized in Table 1. The presenting finding was LC in 66 (35.8%) cases, with an average time-to-leukemia diagnosis of 8.1 months (range, five days-72 months), and aleukemic LC (ALC) in 17 (9.2%) cases. Mean leukemia-to-LC diagnosis interval was 25.6 (range, 0-180 months). Acute myeloblastic leukemia (AML) was the most common type, found in 82 (44.5%) cases, out of which, M5, M4, and M2 variants were predominant at 21.9%, 9.7%, and 9.7%, respectively. Sixteen (8.7%) cases were secondary to acute lymphocytic leukemia (ALL), out of which 56.2% were B-cell lineage. Eleven (5.9%) cases were secondary to chronic lymphocytic leukemia (CLL). Other less common types were chronic myelomonocytic leukemia (CMML), myelodysplastic syndromes (MDS), chronic myeloid leukemia (CML), and acute promyelocytic leukemia (APL) in 9 (4.9%), 7 (3.8%), 5 (2.7%), and 5 (2.7%), respectively. The most common treatment modality was chemotherapy in 109/133 (81.9%) cases with the available data, out of which, 80 (73.4%) had chemotherapy alone, 16 (14.7%) had chemotherapy plus stem cell transplantation (SCT), 8 (7.3%) had chemotherapy plus radiotherapy, 3 (2.8%) had chemotherapy plus surgery and radiotherapy, 1 (0.9%) had chemotherapy plus radiation and SCT, and 1 (0.9%) had chemotherapy plus surgery. Mean duration of follow-up was 11 months (range, 1 day-100 months). In terms of outcomes, 61 (33.15%) patients were alive upon follow-up, out of which, 19 (31.1%) in remission, 18 (29.5%) disease-free, 17 (27.9%) with persistent disease, 2 (3.3%) had a recurrence, and 5 (8.2%) outcome not mentioned. Moreover, 91 (49.46%) patients died from disease. For the reported data, the average interval from leukemia diagnosis to death was 4.4 months (range, 3 days-15 months) for AML and 7.6 months (range, four days-25 months) for ALL (Table 2). Interestingly, at the time of our patient's LC diagnosis in our institution, cytogenic analysis revealed a novel inv(11)(p15q23) chromosomal aberration that herald MDS-to-AML transformation. Discussion In this review, several findings are noteworthy. First, males were more commonly affected. Second, 109 (59.2%) patients were older than 50 years of age. Third, LC noted as the initial presentation of systemic disease in more than a third of patients, whereas ALC was the initial presentation in only around 9% of patients. Fourth, multiple cutaneous lesions were more prevalent, with nodules being the most common presentation. Fifth, AML was the most predominant type overall, found in almost 45% of cases, followed by ALL, CLL, CMML, and other less common types. Sixth, chemotherapy was the most common treatment modality overall in more than 80% of patients with reported data. Seventh, almost half of patients died from the disease or complications related to it. Distinctly, very few studies in the literature reported this unique AML association with chromosome 11 aberrations. Conclusion LC is relatively rare and has a dismal prognosis. It most likely presents as the initial manifestation of leukemia, and physicians could easily misdiagnose this condition if managed without a biopsy. In this study, we intend to promote early recognition among physicians and highlight our unique cytogenetic findings. This could support future endeavors and develop novel patient-specific therapeutic strategies that exploit chromosomal aberrations amidst possible leukemogenic mechanisms. Disclosures No relevant conflicts of interest to declare.


CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S106-S107
Author(s):  
L. Siddiqi ◽  
K. Van Aarsen ◽  
A. Iansavitchene ◽  
J. W. Yan

Introduction: Hyperglycemia is a significant cause of morbidity and mortality, often resulting in adverse outcomes such as recurrent ED visits, hospitalization or death. The objective of this study was to perform a systematic review to identify predictors of these adverse outcomes among patients who present to the ED with hyperglycemia. Methods: Electronic searches of Medline and EMBASE were conducted for studies published in English between the years 1946 and June 2017. Studies with patients presenting to the ED with hyperglycemia were eligible for inclusion. Both adult and pediatric populations were included, as were diabetic and non-diabetic patients. Two reviewers independently screened all titles and abstracts for relevance to the research question. If consensus could not be reached, full-length manuscripts were reviewed. For any discrepancy, a third reviewer was consulted, and disagreement was resolved through discussion. Study quality was assessed using the Newcastle-Ottawa Quality Assessment Scale. Study- and patient-specific data were then extracted and presented descriptively in the systematic review. Results: Thirteen observational studies were included, with a combined total of 664,829 patients. The studies scored between 5 to 8 on the Quality Assessment Scale out of a possible total of 8. Predictors of adverse outcomes included patients in both older and younger (< 25) age groups, history of diabetes, multiple comorbidities, patients requiring insulin, sepsis and hyperlactatemia, access to a family physician, a sentinel hyperglycemia visit in the past month, and triage glucose level > 20 mmol/L. Protective factors included no admissions in the past year, care from a diabetes team while in hospital, systolic blood pressure between 90-150 mmHg and heart rate > 110 bpm. Conclusion: This systematic review found eight predictors and four protective factors for adverse outcomes in patients presenting to the ED with hyperglycemia. These factors should be considered for easier identification of higher-risk patients for adverse outcomes in order to guide management and follow-up.


Author(s):  
Marco Recenti ◽  
Carlo Ricciardi ◽  
Kyle Edmunds ◽  
Deborah Jacob ◽  
Monica Gambacorta ◽  
...  

Aging well is directly associated to a healthy lifestyle. The focus of this paper is to relate individual wellness with medical image features. Non-linear trimodal regression analysis (NTRA) is a novel method that models the radiodensitometric distributions of x-ray computed tomography (CT) cross-sections. It generates 11 patient-specific parameters that describe the quality and quantity of muscle, fat, and connective tissues. In this research, the relationship of these 11 NTRA parameters with age, physical activity, and lifestyle is investigated in the 3,157 elderly volunteers AGES-I dataset. First, univariate statistical analyses were performed, and subjects were grouped by age and self-reported past (youth–midlife) and present (within 12 months of the survey) physical activity to ascertain which parameters were the most influential. Then, machine learning (ML) analyses were conducted to classify patients using NTRA parameters as input features for three ML algorithms. ML is also used to classify a Lifestyle index using the age groups. This classification analysis yielded robust results with the lifestyle index underlying the relevant differences of the soft tissues between age groups, especially in fat and connective tissue. Univariate statistical models suggested that NTRA parameters may be susceptible to age and differences between past and present physical activity levels. Moreover, for both age and physical activity, lean muscle parameters expressed more significant variation than fat and connective tissues.


2019 ◽  
Vol 8 (2) ◽  
pp. 6047-6052

Wind Energy is turning into a big supply of renewable energy throughout the globe. This ever increasing field can probably reach the limit of accessibility and utility with the wind energy facility sites and size of the turbine itself. Therefore, it's needed to develop wind capturing devices that may produce energy within the locations wherever typical horizontal axis wind turbines (HAWTs) are too unrealistic to put in and operate. A diffuser augmented wind turbine (DAWT) is one such invention. DAWTs increase the ability output of the rotor by increasing the wind speed into the rotor employing a duct. The main objective of the project is to analyze the flow through the diffuser by placing it in wind tunnel and further the results are compared with the computational results. The purpose of investigating the flow through, the diffuser is to find out the behavior of wind flow at the throat region of the diffuser. Numerical analysis of diffuser is performed using the tool ANSYS FLUENT 15 and then by experimentation in wind tunnel. Experiments were carried out for investigating the flow pattern inside the circular profile diffuser of radius 60mm, Throat diameter of 200mm, inlet and outlet diameter of diffuser is 320mm. Pitot tubes are inserted on the rake and then mount on the throat region of diffuser for flow measurement in that region. Differential pressure transducers which gives voltage output are used for sensing the pressures from Pitot tubes, static tubes which is mount on surface of test section of tunnel and PS tube which is used for reference velocity. Further obtained pressure will be converted to velocity and get the required result. After completion of computational and experimental work comparable results were obtained.


2019 ◽  
Vol 21 (4) ◽  
pp. 276-282
Author(s):  
Apar Pokharel

Foreign bodies are frequently encountered otorhinolaryngology emergency. The objective of this research paper is to analyze different foreign bodies in terms of type, site, age, and gender distribution and methods of removal. A retrospective study was performed from March, 2018 to March, 2019 in a tertiary care hospital in the central part of Nepal. The information was obtained from hospital record books. A total of 315 patients visited the hospital with a foreign body in either of their ear, nose or throat. It comprised of approximately 12% of all the ENT emergencies in the hospital in the last one year of study. Foreign bodies in ear, nose and throat region were found in all age groups, although it was more prevalent among children of age group less than 10 years.


1988 ◽  
Vol 22 (12) ◽  
pp. 999-1002 ◽  
Author(s):  
Joseph O. Olubadewo ◽  
Ann Ikponmwamba

This retrospective study describes the prescription medication profile in an outpatient pediatric population (n = 510) retrieved from a hospital pharmacy computer file. The survey covers a three-month period. The study population included 281 male and 229 female patients divided according to age into three groups: infant (age 0–12 months); children (age 1–12 years); and adolescents (age 13–18 years). Medications prescribed were classified according to their pharmacotherapeutic properties as described in the American Hospital Formulary Service Drug Information 87. The findings pointed out that three pharmacotherapeutic categories (the antiinfective/chemotherapeutic, central nervous system (CNS), and respiratory agents) constituted 78.1 percent of the 1402 prescribed medications. The most frequently prescribed agents in each of these categories were, respectively, amoxicillin, aminophylline, and acetaminophen. These agents represent recent advances in drug usage because they became most frequently used only within the past ten years. The age-dependent medication profile indicated that there was a higher prescription rate of antiinfectives and respiratory disorder agents in the younger age groups; in the adolescent group CNS agents were more often prescribed.


Author(s):  
Oshri Wasserzug ◽  
Gadi Fishman ◽  
Narin Carmel-Neiderman ◽  
Yael Oestreicher-Kedem ◽  
Maher Saada ◽  
...  

Abstract Background Preoperative planning of open laryngotracheal surgery is important for achieving good results. This study examines the surgeon’s perception of the importance of using life size 3D printed models of the pediatric airway on surgical decision making. Methods Life-size three-dimensional models of the upper airway were created based on CT images of children scheduled for laryngotracheal-reconstruction and cricotracheal resection with anastomosis. Five pediatric airway surgeons evaluated the three-dimensional models for determining the surgical approach, incision location and length, graft length, and need for single or double-stage surgery of seven children (median age 4.4 years, M:F ratio 4:3). They rated the importance of the three-dimensional model findings compared to the direct laryngoscopy videos and CT findings for each domain on a validated Likert scale of 1–5. Results The mean rating for all domains was 3.6 ± 0.63 (“moderately important” to “very important”), and the median rating was 4 (“very important”). There was full agreement between raters for length of incision and length of graft. The between-rater agreement was 0.608 (“good”) for surgical approach, 0.585 (“moderate”) for incision location, and 0.429 (“moderate”) for need for single- or two-stage surgery. Conclusion Patient-specific three-dimensional printed models of children’s upper airways were scored by pediatric airway surgeons as being moderately to very important for preoperative planning of open laryngotracheal surgery. Large–scale, objective outcome studies are warranted to establish the reliability and efficiency of these models. Graphical abstract


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