scholarly journals Severe loss of mechanical efficiency in COVID‐19 patients

2021 ◽  
Author(s):  
Eulogio Pleguezuelos ◽  
Amin Del Carmen ◽  
Gemma Llorensi ◽  
Jessica Carcole ◽  
Paula Casarramona ◽  
...  
Keyword(s):  
Mechanical Efficiency ◽  
Severe Loss

Retrieval of fractured Endodontic Instrument under dental operating microscope using ultrasonic tips : A Case Report

2020 ◽  
Vol 11 (3) ◽  
pp. 3316-3321
Author(s):  
Samrudhi Khatod ◽  
Anuja Ikhar ◽  
Pradnya Nikhade ◽  
Manoj chandak
Keyword(s):  
Case Report ◽  
Root Canal ◽  
Fracture Resistance ◽  
Root Canal Treatment ◽  
Operating Microscope ◽  
Severe Loss ◽  
Mechanical Procedure ◽  
Root Dentin ◽  
Fracture Level

A Patient came with the complaint of pain in the lower right back region of the jaw. Root canal treatment was planned. While preparing for the bio-mechanical procedure, the Hand pro taper fractured in the apical third. Iatrogenic occurred as a result of the fracture of the endodontic instrument. Retrieval of the fractured instrument was planned to complete the cleaning and shaping of the canal. The removal of the fractured instrument was planned to be done under the Dental Operating Microscope. The use of an operating microscope enhanced the illumination and the magnification of the instrument. This illumination and magnification helped in the precision of removal. The ultrasonic tip enabled to reach of the fractured instrument in the canal and loosen the dentin around the fractured instrument. It allowed easy retrieval of the fractured instrument. During the retrieval procedure, the fractured instrument was bypassed before the use of the ultrasonic tip. After the removal of the fractured instrument, cleaning and shaping were completed, followed by obturation, definitive restoration, and prosthesis. As the removal of the fractured instrument enabled complete cleaning and shaping, it improved the prognosis of the case. When the endodontic instrument gets fractured, it should be analyzed over the radiograph to assess the fracture level, the anatomy of the root canal, size of the fractured instrument, check accessibility, stage of fracture, etc. If all the above criteria are met with the removal of the instrument only then, replacement should be tried. Otherwise, it may lead to a severe loss of root dentin, decreasing fracture resistance of the root.

Application of Monoterpenoids and their Derivatives for Treatment of Neurodegenerative Disorders

2019 ◽  
Vol 25 (39) ◽  
pp. 5327-5346 ◽  
Author(s):  
Konstantin P. Volcho ◽  
Sergey S. Laev ◽  
Ghulam Md Ashraf ◽  
Gjumrakch Aliev ◽  
Nariman F. Salakhutdinov
Keyword(s):  
Alzheimer’S Disease ◽  
Clinical Trials ◽  
Huntington's Disease ◽  
Neurodegenerative Disorders ◽  
Heterogeneous Group ◽  
Neuroprotective Activity ◽  
Severe Loss ◽  
Neurotrophic Activity ◽  
Full Proof ◽  
Effective Treatments

Neurodegenerative disorders (NDDs) like Alzheimer's disease, Parkinson’s disease and Huntington’s disease are a heterogeneous group of disorders with the progressive and severe loss of neurons. There are no full proof cures for these diseases, and only medicines are available that can alleviate some of the symptoms. Developing effective treatments for the NDDs is a difficult but necessary task. Hence, the investigation of monoterpenoids which modulate targets applicable to many NDDs is highly relevant. Many monoterpenoids have demonstrated promising neuroprotective activity mediated by various systems. It can form the basis for elaboration of agents which will be useful both for the alleviation of symptoms of NDDs and for the treatment of diseases progression and also for prevention of neurodegeneration. The further developments including detections of monoterpenoids and their derivatives with high neuroprotective or neurotrophic activity as well as the results of qualified clinical trials are needed to draw solid conclusions regarding the efficacy of these agents.

scholarly journals Analytical Modeling and Simulation of S-Drive Piezoelectric Actuators

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 87
Author(s):  
Nicholas A. Jones ◽  
Jason Clark
Keyword(s):  
Element Model ◽  
Mechanical Efficiency ◽  
Compact Model ◽  
High Frequency Response ◽  
Macro Scale ◽  
Piezoelectric Structure ◽  
Modern Manufacturing ◽  
Manufacturing Techniques ◽  
Piezoelectric Structures ◽  
Improve Device

This paper presents a structural geometry for increasing piezoelectric deformation, which is suitable for both micro- and macro-scale applications. New and versatile microstructure geometries for actuators can improve device performance, and piezoelectric designs benefit from a high-frequency response, power density, and efficiency, making them a viable choice for a variety of applications. Previous works have presented piezoelectric structures capable of this amplification, but few are well-suited to planar manufacturing. In addition to this manufacturing difficulty, a large number of designs cannot be chained into longer elements, preventing them from operating at the macro-scale. By optimizing for both modern manufacturing techniques and composability, this structure excels as an option for a variety of macro- and micro-applications. This paper presents an analytical compact model of a novel dual-bimorph piezoelectric structure, and shows that this compact model is within 2% of a computer-distributed element model. Furthermore it compares the actuator’s theoretical performance to that of a modern actuator, showing that this actuator trades mechanical efficiency for compactness and weight savings.

scholarly journals Noninvasive Assessment of Neuromechanical Coupling and Mechanical Efficiency of Parasternal Intercostal Muscle during Inspiratory Threshold Loading

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1781
Author(s):  
Manuel Lozano-García ◽  
Luis Estrada-Petrocelli ◽  
Abel Torres ◽  
Gerrard F. Rafferty ◽  
John Moxham ◽  
...  
Keyword(s):  
Mechanical Efficiency ◽  
Intercostal Muscle ◽  
Wireless Devices ◽  
Clinical Value ◽  
Intercostal Muscles ◽  
Noninvasive Measurements ◽  
Standard Assessment ◽  
Mouth Pressure ◽  
Invasive Techniques ◽  
Increasing Load

This study aims to investigate noninvasive indices of neuromechanical coupling (NMC) and mechanical efficiency (MEff) of parasternal intercostal muscles. Gold standard assessment of diaphragm NMC requires using invasive techniques, limiting the utility of this procedure. Noninvasive NMC indices of parasternal intercostal muscles can be calculated using surface mechanomyography (sMMGpara) and electromyography (sEMGpara). However, the use of sMMGpara as an inspiratory muscle mechanical output measure, and the relationships between sMMGpara, sEMGpara, and simultaneous invasive and noninvasive pressure measurements have not previously been evaluated. sEMGpara, sMMGpara, and both invasive and noninvasive measurements of pressures were recorded in twelve healthy subjects during an inspiratory loading protocol. The ratios of sMMGpara to sEMGpara, which provided muscle-specific noninvasive NMC indices of parasternal intercostal muscles, showed nonsignificant changes with increasing load, since the relationships between sMMGpara and sEMGpara were linear (R2 = 0.85 (0.75–0.9)). The ratios of mouth pressure (Pmo) to sEMGpara and sMMGpara were also proposed as noninvasive indices of parasternal intercostal muscle NMC and MEff, respectively. These indices, similar to the analogous indices calculated using invasive transdiaphragmatic and esophageal pressures, showed nonsignificant changes during threshold loading, since the relationships between Pmo and both sEMGpara (R2 = 0.84 (0.77–0.93)) and sMMGpara (R2 = 0.89 (0.85–0.91)) were linear. The proposed noninvasive NMC and MEff indices of parasternal intercostal muscles may be of potential clinical value, particularly for the regular assessment of patients with disordered respiratory mechanics using noninvasive wearable and wireless devices.

Numerical simulation and experimental performance research of cylindrical vane pump

2021 ◽  
pp. 095440622110200
Author(s):  
Yiqi Cheng ◽  
Xinhua Wang ◽  
Waheed Ur Rehman ◽  
Tao Sun ◽  
Hasan Shahzad ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Rotational Velocity ◽  
Geometric Theory ◽  
Mechanical Efficiency ◽  
Operating Conditions ◽  
Experimental Results ◽  
Field Analysis ◽  
Total Efficiency ◽  
Three Dimensional Model ◽  
Vane Pump

This study presents a novel cylindrical vane pump based on the traditional working principle. The efficiency of the cylindrical vane pump was verified by experimental validation and numerical analysis. Numerical analysis, such as kinematics analysis, was performed in Pro/Mechanism and unsteady flow-field analysis was performed using ANSYS FLUENT. The stator surface equations were derived using the geometric theory of the applied spatial triangulation function. A three-dimensional model of the cylindrical vane pump was established with the help of MATLAB and Pro/E. The kinematic analysis helped in developing kinematic equations for cylindrical vane pumps and proved the effectiveness of the structural design. The maximum inaccuracy error of the computational fluid dynamics (CFD) model was 5.7% compared with the experimental results, and the CFD results show that the structure of the pump was reasonable. An experimental test bench was developed, and the results were in excellent agreement with the numerical results of CFD. The experimental results show that the cylindrical vane pump satisfied the three-element design of a positive-displacement pump and the trend of changes in efficiency was the same for all types of efficiency under different operating conditions. Furthermore, the volumetric efficiency presented a nonlinear positive correlation with increased rotational velocity, the mechanical efficiency showed a nonlinear negative correlation, and the total efficiency first increased and then decreased. When the rotational velocity was 1.33[Formula: see text] and the discharge pressure was 0.68[Formula: see text], the total efficiency reached its maximum value.

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