scholarly journals Endotracheal Tubes Design: The Role of Tube Bending

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1503
Author(s):  
Talib Dbouk ◽  
Dimitris Drikakis

Endotracheal tubes (ETT) passed inside the human trachea witness tube bending at different angles, affecting the ocal fluid flow dynamics. This induces a variable mechanical ventilation performance across patients’ comfortability evels. Our understanding of the ocal fluid flow dynamics phenomena is thus crucial to enhance the maneuverability of ETT under operation. For the first time to our knowledge, we shed ight on ETT through computational fluid dynamics (CFD) to investigate the bending effect of ETT on the ocal airflow in volume-controlled mechanical ventilation. We considered an ETT with 180° arc bend configuration, including Murphy’s eye. We identified several flow phenomena associated with the bending, such as flow asymmetries, secondary flows, and vortex dynamics throughout the tube.

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ruining Liu ◽  
Gang Li ◽  
Haoli Ma ◽  
Xianlong Zhou ◽  
Pengcheng Wang ◽  
...  

Abstract Background Ventilator-induced diaphragmatic dysfunction (VIDD) is associated with weaning difficulties, intensive care unit hospitalization (ICU), infant mortality, and poor long-term clinical outcomes. The expression patterns of long noncoding RNAs (lncRNAs) and mRNAs in the diaphragm in a rat controlled mechanical ventilation (CMV) model, however, remain to be investigated. Results The diaphragms of five male Wistar rats in a CMV group and five control Wistar rats were used to explore lncRNA and mRNA expression profiles by RNA-sequencing (RNA-seq). Muscle force measurements and immunofluorescence (IF) staining were used to verify the successful establishment of the CMV model. A total of 906 differentially expressed (DE) lncRNAs and 2,139 DE mRNAs were found in the CMV group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine the biological functions or pathways of these DE mRNAs. Our results revealed that these DE mRNAs were related mainly related to complement and coagulation cascades, the PPAR signaling pathway, cholesterol metabolism, cytokine-cytokine receptor interaction, and the AMPK signaling pathway. Some DE lncRNAs and DE mRNAs determined by RNA-seq were validated by quantitative real-time polymerase chain reaction (qRT-PCR), which exhibited trends similar to those observed by RNA-sEq. Co-expression network analysis indicated that three selected muscle atrophy-related mRNAs (Myog, Trim63, and Fbxo32) were coexpressed with relatively newly discovered DE lncRNAs. Conclusions This study provides a novel perspective on the molecular mechanism of DE lncRNAs and mRNAs in a CMV model, and indicates that the inflammatory signaling pathway and lipid metabolism may play important roles in the pathophysiological mechanism and progression of VIDD.


2021 ◽  
Vol 33 (1) ◽  
pp. 111-119
Author(s):  
M. I. Alamayreh ◽  
A. Fenocchi ◽  
G. Petaccia ◽  
S. Sibilla ◽  
E. Persi

Author(s):  
Koji MORI ◽  
Yoshio TANI ◽  
Kazuhiro TADA ◽  
Kenji NAKAO ◽  
Hiroyuki TOSAKA
Keyword(s):  

Author(s):  
Manas Kumar Mondal ◽  
Govind Sharan Gupta ◽  
Shin-ya Kitamura ◽  
Nobuhiro Maruoka

Recently, the demand of the steel having superior chemical and physical properties has increased for which the content of carbon must be in ultra low range. There are many processes which can produce low carbon steel such as tank degasser and RH (Rheinstahl-Heraeus) processes. It has been claimed that using a new process, called REDA (Revolutionary Degassing Activator), one can achieve the carbon content below 10ppm in less time. REDA process, in terms of installment cost, is in between the tank degasser and RH processes. As such, REDA process has not been studied thoroughly. Fluid flow phenomena affect the decarburization rate the most besides the chemical reaction rate. Therefore, momentum balance equations along with k-? turbulent model have been solved for gas and liquid phases in two-dimension (2D) for REDA process. The fluid flow phenomena have been studied in details for this process by varying gas flow rate, depth of immersed snorkel in the steel, diameter of the snorkel and change in vacuum pressure. It is found that the design of the snorkel affects the melt circulation of the bath significantly.


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