Effect of a powered drive on pushing and pulling forces when transporting bariatric hospital beds

2017 ◽  
Vol 58 ◽  
pp. 59-65 ◽  
Author(s):  
Neal Wiggermann
Keyword(s):  
Hospital Beds ◽  
Pulling Forces ◽  
Pushing And Pulling

scholarly journals Positioning of microtubule organizing centers by cortical pushing and pulling forces

2012 ◽  
Vol 14 (10) ◽  
pp. 105025 ◽  
Author(s):  
Nenad Pavin ◽  
Liedewij Laan ◽  
Rui Ma ◽  
Marileen Dogterom ◽  
Frank Jülicher
Keyword(s):  
Microtubule Organizing Centers ◽  
Pulling Forces ◽  
Pushing And Pulling

scholarly journals Measuring microtubule dynamics

2018 ◽  
Vol 62 (6) ◽  
pp. 725-735 ◽  
Author(s):  
Alexander James Zwetsloot ◽  
Gokhan Tut ◽  
Anne Straube
Keyword(s):  
Small Molecules ◽  
Dynamic Instability ◽  
Microtubule Dynamics ◽  
Regulatory Proteins ◽  
Microtubule Assembly ◽  
Cancer Chemotherapeutics ◽  
Pulling Forces ◽  
Inflammatory Drugs ◽  
And Function ◽  
Pushing And Pulling

Microtubules are key players in cellular self-organization, acting as structural scaffolds, cellular highways, force generators and signalling platforms. Microtubules are polar filaments that undergo dynamic instability, i.e. transition between phases of growth and shrinkage. This allows microtubules to explore the inner space of the cell, generate pushing and pulling forces and remodel themselves into arrays with different geometry and function such as the mitotic spindle. To do this, eukaryotic cells employ an arsenal of regulatory proteins to control microtubule dynamics spatially and temporally. Plants and microorganisms have developed secondary metabolites that perturb microtubule dynamics, many of which are in active use as cancer chemotherapeutics and anti-inflammatory drugs. Here, we summarize the methods used to visualize microtubules and to measure the parameters of dynamic instability to study both microtubule regulatory proteins and the action of small molecules interfering with microtubule assembly and/or disassembly.

scholarly journals Psychophysical basis for maximum pushing and pulling forces: A review and recommendations

2014 ◽  
Vol 44 (2) ◽  
pp. 281-291 ◽  
Author(s):  
Arun Garg ◽  
Thomas Waters ◽  
Jay Kapellusch ◽  
Waldemar Karwowski
Keyword(s):  
Pulling Forces ◽  
Pushing And Pulling

scholarly journals Assembly and Activity of the WASH Molecular Machine: Distinctive Features at the Crossroads of the Actin and Microtubule Cytoskeletons

2021 ◽  
Vol 9 ◽  
Author(s):  
Artem I. Fokin ◽  
Alexis M. Gautreau
Keyword(s):  
Cell Cortex ◽  
Membrane Remodeling ◽  
Distinctive Features ◽  
Actin Networks ◽  
Capping Protein ◽  
Endosomal Membrane ◽  
Pulling Forces ◽  
Endosomal Membranes ◽  
Privileged Site ◽  
Pushing And Pulling

The Arp2/3 complex generates branched actin networks at different locations of the cell. The WASH and WAVE Nucleation Promoting Factors (NPFs) activate the Arp2/3 complex at the surface of endosomes or at the cell cortex, respectively. In this review, we will discuss how these two NPFs are controlled within distinct, yet related, multiprotein complexes. These complexes are not spontaneously assembled around WASH and WAVE, but require cellular assembly factors. The centrosome, which nucleates microtubules and branched actin, appears to be a privileged site for WASH complex assembly. The actin and microtubule cytoskeletons are both responsible for endosome shape and membrane remodeling. Motors, such as dynein, pull endosomes and extend membrane tubules along microtubule tracks, whereas branched actin pushes onto the endosomal membrane. It was recently uncovered that WASH assembles a super complex with dynactin, the major dynein activator, where the Capping Protein (CP) is exchanged from dynactin to the WASH complex. This CP swap initiates the first actin filament that primes the autocatalytic nucleation of branched actin at the surface of endosomes. Possible coordination between pushing and pulling forces in the remodeling of endosomal membranes is discussed.

scholarly journals Development of a Motorized Hospital Bed with Swerve Drive Modules for Holonomic Mobility

2021 ◽  
Vol 11 (23) ◽  
pp. 11356
Author(s):  
Radon Dhelika ◽  
Ali Fajar Hadi ◽  
Prasandhya Astagiri Yusuf
Keyword(s):  
Trajectory Planning ◽  
Pid Control ◽  
Constant Velocity ◽  
Average Error ◽  
Physical Injury ◽  
Control Performance ◽  
Dc Motors ◽  
Hospital Beds ◽  
Hospital Bed ◽  
Pushing And Pulling

In hospitals; transferring patients using hospital beds is time consuming and inefficient. Additionally; the task of frequently pushing and pulling beds poses physical injury risks to nurses and caregivers. Motorized hospital beds with holonomic mobility have been previously proposed. However; most such beds come with complex drivetrain which makes them costly and hinders larger-scale adoption in hospitals. In this study; a motorized hospital bed that utilizes a swerve drive mechanism is proposed. The design takes into account simplicity which would allow for minimum modification of the existing beds. Two DC motors for steering and propulsion are used for a single swerve drive module. The control of the propulsion motor is achieved by a combination of trajectory planning based on quintic polynomials and PID control. Further; the control performance of the proposed bed was evaluated; and the holonomic mobility of its prototype was successfully demonstrated. An average error of less than 3% was obtained for motion with a constant velocity; however; larger values in the range of 15% were observed for other conditions, such as accelerating and decelerating.

scholarly journals Jumping without slipping: leafhoppers (Hemiptera: Cicadellidae) possess special tarsal structures for jumping from smooth surfaces

2017 ◽  
Vol 14 (130) ◽  
pp. 20170022 ◽  
Author(s):  
Christofer J. Clemente ◽  
Hanns Hagen Goetzke ◽  
James M. R. Bullock ◽  
Gregory P. Sutton ◽  
Malcolm Burrows ◽  
...  
Keyword(s):  
High Speed ◽  
Smooth Surfaces ◽  
Velocity Dependence ◽  
Force Measurements ◽  
Acceleration Phase ◽  
Friction Forces ◽  
Anisotropic Friction ◽  
Rapid Control ◽  
Pulling Forces ◽  
Pushing And Pulling

Many hemipteran bugs can jump explosively from plant substrates, which can be very smooth. We therefore analysed the jumping performance of froghoppers ( Philaenus spumarius, Aphrophoridae) and leafhoppers ( Aphrodes bicinctus/makarovi, Cicadellidae) taking off from smooth (glass) and rough (sandpaper, 30 µm asperity size) surfaces. On glass, the propulsive hind legs of Philaenus froghoppers slipped, resulting in uncontrolled jumps with a fast forward spin, a steeper angle and only a quarter of the velocity compared with jumps from rough surfaces. By contrast, Aphrodes leafhoppers took off without their propulsive hind legs slipping, and reached low take-off angles and high velocities on both substrates. This difference in jumping ability from smooth surfaces can be explained not only by the lower acceleration of the long-legged leafhoppers, but also by the presence of 2–9 soft pad-like structures (platellae) on their hind tarsi, which are absent in froghoppers. High-speed videos of jumping showed that platellae contact the surface briefly (approx. 3 ms) during the acceleration phase. Friction force measurements on individual hind tarsi on glass revealed that at low sliding speeds, both pushing and pulling forces were small, and insufficient to explain the recorded jumps. Only when the tarsi were pushed with higher velocities did the contact area of the platellae increase markedly, and high friction forces were produced, consistent with the observed jumps. Our findings show that leafhoppers have special adhesive footpads for jumping from smooth surfaces, which achieve firm grip and rapid control of attachment/detachment by combining anisotropic friction with velocity dependence.

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