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Trends in Microbiology Nov 2021The bacterial flagellar motor, a remarkable rotary machine, can rapidly switch between counterclockwise (CCW) and clockwise (CW) rotational directions to control the... (Review)
Review
The bacterial flagellar motor, a remarkable rotary machine, can rapidly switch between counterclockwise (CCW) and clockwise (CW) rotational directions to control the migration behavior of the bacterial cell. The flagellar motor consists of a bidirectional spinning rotor surrounded by torque-generating stator units. Recent high-resolution in vitro and in situ structural studies have revealed stunning details of the individual components of the flagellar motor and their interactions in both the CCW and CW senses. In this review, we discuss these structures and their implications for understanding the molecular mechanisms underlying flagellar rotation and switching.
Topics: Bacteria; Bacterial Proteins; Flagella; Molecular Motor Proteins; Rotation; Torque
PubMed: 33865677
DOI: 10.1016/j.tim.2021.03.009 -
Scientific Reports Nov 2023Many diseases, including cancer and covid, result in altered mechanical and electric properties of the affected cells. These changes were proposed as disease markers....
Many diseases, including cancer and covid, result in altered mechanical and electric properties of the affected cells. These changes were proposed as disease markers. Current methods to characterize such changes either provide very limited information on many cells or have extremely low throughput. We introduce electro-acoustic spinning (EAS). Cells were found to spin in combined non-rotating AC electric and acoustic fields. The rotation velocity in EAS depends critically on a cell's electrical and mechanical properties. In contrast to existing methods, the rotation is uniform in the field of view and hundreds of cells can be characterized simultaneously. We demonstrate that EAS can distinguish cells with only minor differences in electric and mechanical properties, including differences in age or the number of passages.
Topics: Electricity; Rotation; Acoustics; Acoustic Stimulation; Electric Stimulation; Cochlear Implants; Cochlear Implantation
PubMed: 37993513
DOI: 10.1038/s41598-023-46550-w -
BMJ Global Health Jul 2021Rotation work, characterised by travelling long distances to work in isolated areas where workers typically rotate consecutive days working and living on-site with...
INTRODUCTION
Rotation work, characterised by travelling long distances to work in isolated areas where workers typically rotate consecutive days working and living on-site with periods at home, is increasingly used in the resources and construction sectors globally. Such employment practices may have an impact on workers' health and well-being. This systematic review explores the impact rotation work has on mental and physical outcomes in rotation workers in the resources and construction sectors.
METHOD
The PubMed, Medline, EMBASE, CINAHL, PsycINFO, and Scopus databases were systematically searched on 1 May 2020 to identify quantitative, qualitative and mixed-method studies addressing the health of rotation workers published in peer-reviewed journals. Findings from the studies were summarised narratively.
RESULTS
Of 6268 studies retrieved, 90 studies were included in the review. Studies suggested higher prevalence of psychological distress in onshore rotation workers and higher overweight/obesity rates among rotation workers as compared with the general population. We found more sleep problems and higher levels of smoking during work periods compared with off-site days; and higher alcohol intake during off-site days compared with on-site days. Workers generally perceived their physical health status as good. High-perceived job demands (such as workload, repetitive work) were associated with mental distress and exhaustion, sleep problems and perceived poor physical health status, while high-perceived job resources (such as job clarity/control, support) were associated with low mental distress and exhaustion, less smoking and alcohol intake, and better sleep.
CONCLUSION
Rotation work is associated with several poorer health behaviours and outcomes, such as sleep problems, smoking, alcohol consumption and overweight/obesity. Interventions needed to improve rotation workers' health should include maximising available job resources and reducing job demands. Further longitudinal studies are needed to explore the long-term health effects of rotation work and the short-term contextual effects of the different aspects of rotation work.
Topics: Construction Industry; Humans; Occupational Health; Rotation; Workload
PubMed: 34301674
DOI: 10.1136/bmjgh-2021-005112 -
Nature Communications May 2022For many bacteria, motility stems from one or more flagella, each rotated by the bacterial flagellar motor, a powerful rotary molecular machine. The hook, a soft polymer...
For many bacteria, motility stems from one or more flagella, each rotated by the bacterial flagellar motor, a powerful rotary molecular machine. The hook, a soft polymer at the base of each flagellum, acts as a universal joint, coupling rotation between the rigid membrane-spanning rotor and rigid flagellum. In multi-flagellated species, where thrust arises from a hydrodynamically coordinated flagellar bundle, hook flexibility is crucial, as flagella rotate significantly off-axis. However, consequently, the thrust applies a significant bending moment. Therefore, the hook must simultaneously be compliant to enable bundle formation yet rigid to withstand large hydrodynamical forces. Here, via high-resolution measurements and analysis of hook fluctuations under dynamical conditions, we elucidate how it fulfills this double functionality: the hook shows a dynamic increase in bending stiffness under increasing torsional stress. Such strain-stiffening allows the system to be flexible when needed yet reduce deformation under high loads, enabling high speed motility.
Topics: Bacteria; Bacterial Proteins; Cell Membrane Structures; Flagella; Rotation
PubMed: 35614041
DOI: 10.1038/s41467-022-30295-7 -
Sensors (Basel, Switzerland) Mar 2022The requirement to estimate the six degree-of-freedom pose of a moving platform frequently arises in automation applications. It is common to estimate platform pose by...
The requirement to estimate the six degree-of-freedom pose of a moving platform frequently arises in automation applications. It is common to estimate platform pose by the fusion of global navigation satellite systems (GNSS) measurements and translational acceleration and rotational rate measurements from an inertial measurement unit (IMU). This paper considers a specific situation where two GNSS receivers and one IMU are used and gives the full formulation of a Kalman filter-based estimator to do this. A limitation in using this sensor set is the difficulty of obtaining accurate estimates of the degree of freedom corresponding to rotation about the line passing through the two GNSS receiver antenna centres. The GNSS-aided IMU formulation is extended to incorporate LiDAR measurements in both known and unknown environments to stabilise this degree of freedom. The performance of the pose estimator is established by comparing expected LiDAR range measurements with actual range measurements. Distributions of the terrain point-to-model error are shown to improve from 0.27m mean error to 0.06m when the GNSS-aided IMU estimator is augmented with LiDAR measurements. This precision is marginally degraded to 0.14m when the pose estimator is operated in an unknown environment.
Topics: Acceleration; Rotation
PubMed: 35336417
DOI: 10.3390/s22062248 -
Medicina (Kaunas, Lithuania) Jan 2021Sleeper stretching (SS) can improve the shoulder's range of motion (ROM) for pitchers with glenohumeral internal rotation deficit (GIRD). However, no evidence has proven...
Comparison of the Acute Effects of Kinesio Taping and Sleeper Stretching on the Shoulder Rotation Range of Motion, Manual Muscle Strength, and Sub-Acromial Space in Pitchers with Glenohumeral Internal Rotation Deficit.
BACKGROUND AND OBJECTIVES
Sleeper stretching (SS) can improve the shoulder's range of motion (ROM) for pitchers with glenohumeral internal rotation deficit (GIRD). However, no evidence has proven the effect of Kinesio taping (KT) on shoulder strength and ROM. Therefore, this study compared the effects of SS and KT on shoulder rotation ROM, muscle strength, and sub-acromial distance in pitchers with GIRD.
MATERIALS AND METHODS
Thirty-one pitchers with GIRD were allocated into control, KT, and SS groups. Shoulder rotation ROM, muscle strength, and sub-acromial space were measured before and after treatment with SS or KT.
RESULTS
The results revealed that KT and SS significantly enhanced shoulder rotation ROM in pitchers with GIRD. External rotator strength significantly increased following KT but significantly decreased after SS. KT and SS exerted no effects on the sub-acromial space.
CONCLUSIONS
KT and SS improve shoulder rotation ROM in pitchers with GIRD. In addition, KT improves shoulder external rotator strength, and SS reduces it.
Topics: Baseball; Humans; Muscle Strength; Range of Motion, Articular; Rotation; Shoulder; Shoulder Joint
PubMed: 33498704
DOI: 10.3390/medicina57020102 -
Bioinformatics (Oxford, England) Jul 2019Neural networks have been widely used to analyze high-throughput microscopy images. However, the performance of neural networks can be significantly improved by encoding...
MOTIVATION
Neural networks have been widely used to analyze high-throughput microscopy images. However, the performance of neural networks can be significantly improved by encoding known invariance for particular tasks. Highly relevant to the goal of automated cell phenotyping from microscopy image data is rotation invariance. Here we consider the application of two schemes for encoding rotation equivariance and invariance in a convolutional neural network, namely, the group-equivariant CNN (G-CNN), and a new architecture with simple, efficient conic convolution, for classifying microscopy images. We additionally integrate the 2D-discrete-Fourier transform (2D-DFT) as an effective means for encoding global rotational invariance. We call our new method the Conic Convolution and DFT Network (CFNet).
RESULTS
We evaluated the efficacy of CFNet and G-CNN as compared to a standard CNN for several different image classification tasks, including simulated and real microscopy images of subcellular protein localization, and demonstrated improved performance. We believe CFNet has the potential to improve many high-throughput microscopy image analysis applications.
AVAILABILITY AND IMPLEMENTATION
Source code of CFNet is available at: https://github.com/bchidest/CFNet.
SUPPLEMENTARY INFORMATION
Supplementary data are available at Bioinformatics online.
Topics: Microscopy; Neural Networks, Computer; Rotation; Software
PubMed: 31510662
DOI: 10.1093/bioinformatics/btz353 -
Biochimica Et Biophysica Acta Aug 2010Two proton pumps, the F-ATPase (ATP synthase, FoF1) and the V-ATPase (endomembrane proton pump), have different physiological functions, but are similar in subunit... (Review)
Review
Two proton pumps, the F-ATPase (ATP synthase, FoF1) and the V-ATPase (endomembrane proton pump), have different physiological functions, but are similar in subunit structure and mechanism. They are composed of a membrane extrinsic (F1 or V1) and a membrane intrinsic (Fo or Vo) sector, and couple catalysis of ATP synthesis or hydrolysis to proton transport by a rotational mechanism. The mechanism of rotation has been extensively studied by kinetic, thermodynamic and physiological approaches. Techniques for observing subunit rotation have been developed. Observations of micron-length actin filaments, or polystyrene or gold beads attached to rotor subunits have been highly informative of the rotational behavior of ATP hydrolysis-driven rotation. Single molecule FRET experiments between fluorescent probes attached to rotor and stator subunits have been used effectively in monitoring proton motive force-driven rotation in the ATP synthesis reaction. By using small gold beads with diameters of 40-60 nm, the E. coli F1 sector was found to rotate at surprisingly high speeds (>400 rps). This experimental system was used to assess the kinetics and thermodynamics of mutant enzymes. The results revealed that the enzymatic reaction steps and the timing of the domain interactions among the beta subunits, or between the beta and gamma subunits, are coordinated in a manner that lowers the activation energy for all steps and avoids deep energy wells through the rotationally-coupled steady-state reaction. In this review, we focus on the mechanism of steady-state F1-ATPase rotation, which maximizes the coupling efficiency between catalysis and rotation.
Topics: Adenosine Triphosphate; Animals; Catalysis; Humans; Proton-Translocating ATPases; Rotation; Thermodynamics; Vacuolar Proton-Translocating ATPases
PubMed: 20170625
DOI: 10.1016/j.bbabio.2010.02.014 -
Clinical Oral Investigations Mar 2022To three-dimensionally evaluate deviations of full-arch intraoral (IO) scans from reference desktop scans in terms of translations and rotations of individual teeth and...
OBJECTIVES
To three-dimensionally evaluate deviations of full-arch intraoral (IO) scans from reference desktop scans in terms of translations and rotations of individual teeth and different types of (mal)occlusion.
MATERIALS AND METHODS
Three resin model pairs reflecting different tooth (mal)positions were mounted in the phantom head of a dental simulation unit and scanned by three dentists and three non-graduate investigators using a confocal laser IO scanner (Trios 3®). The tooth-crown surfaces of the IO scans and reference scans were superimposed by means of best-fit alignment. A novel method comprising the measurement of individual tooth positions was used to determine the deviations of each tooth in the six degrees of freedom, i.e., in terms of 3D translation and rotation. Deviations between IO and reference scans, among tooth-(mal)position models, and between dentists and non-graduate investigators were analyzed using linear mixed-effects models.
RESULTS
The overall translational deviations of individual teeth on the IO scans were 76, 32, and 58 µm in the lingual, mesial, and intrusive directions, respectively, resulting in a total displacement of 114 µm. Corresponding rotational deviations were 0.58° buccal tipping, 0.04° mesial tipping, and 0.14° distorotation leading to a combined rotation of 0.78°. These deviations were the smallest for the dental arches with anterior crowding, followed by those with spacing and those with good alignment (p < 0.05). Results were independent of the operator's level of education.
CONCLUSIONS
Compared to reference desktop scans, individual teeth on full-arch IO scans showed high trueness with total translational and rotational deviations < 115 µm and < 0.80°, respectively.
CLINICAL RELEVANCE
Available confocal laser IO scanners appear sufficiently accurate for diagnostic and therapeutic orthodontic applications. Results indicate that full-arch IO scanning can be delegated to non-graduate dental staff members.
Topics: Computer-Aided Design; Dental Arch; Dental Impression Technique; Humans; Imaging, Three-Dimensional; Models, Dental; Orthodontic Appliance Design; Rotation
PubMed: 34837565
DOI: 10.1007/s00784-021-04309-5 -
Optics Express Oct 2008The optical cell rotator (OCR) is a modified dual-beam laser trap for the holding and controlled rotation of suspended dielectric microparticles, such as cells. In...
The optical cell rotator (OCR) is a modified dual-beam laser trap for the holding and controlled rotation of suspended dielectric microparticles, such as cells. In contrast to optical tweezers, OCR uses two counter-propagating divergent laser beams, which are shaped and delivered by optical fibers. The rotation of a trapped specimen is carried out by the rotation of a dual-mode fiber, emitting an asymmetric laser beam. Experiments were performed on human erythrocytes, promyelocytic leukemia cells (HL60), and cell clusters (MCF-7). Since OCR permits the rotation of cells around an axis perpendicular to the optical axis of any microscope and is fully decoupled from imaging optics, it could be a suitable and expedient tool for tomographic microscopy.
Topics: Cell Separation; Equipment Design; Equipment Failure Analysis; Micromanipulation; Optical Fibers; Optical Tweezers; Rotation
PubMed: 18852807
DOI: 10.1364/oe.16.016984