Torque force in the kinesin stroke drives coupled yaw axis and orbital rotations of kinesin coated gold nanorods

Kinesin motor domains generate impulses of force and movement that have both translational and rotational components, raising the question of how the rotational component contributes to motor function. We used a new assay in which kinesin-coated gold nanorods (kinesin-GNRs) move on suspended microtubules, for three plus-end-directed kinesins: single-headed KIF1A, dimeric ZEN-4 and single-headed kinesin-1. Polarization of the light scattered by all three types of kinesin-GNRs periodically oscillated as they orbited the microtubule along a left-handed helical trajectory. Our analyses revealed that each kinesin-GNR unidirectionally rotates about its yaw axis as it translocates, and that the period of this yaw-axis rotation corresponds to two periods of its left-handed helical orbit around the microtubule axis. Stochastic simulations suggest that the yaw-axis rotation enhances biased lateral displacement of the kinesin team. Our study reveals biaxial rotation as a new mode of motility in kinesin teams that helps the team to sidestep obstacles.

Anterior Inferior Hip Dislocation: Report of Three Cases and Review of Literature

Introduction: Inferior dislocation of the hip, also called luxatio erecta femoris, is the rarest type of hip dislocation with a poorly understood mechanism of injury. We came across three such cases resulting from high-energy trauma with various other associated injuries. Case Report: The first patient, a 25-year-old man, presented with the right hip pain, hip and knee joint in flexion without rotational component, after motor vehicle collision. The second patient, a 42-year-old man, presented with the left hip pain, hip and knee joint in flexion with rotational component, following fall from 20 ft height. The third patient, a 29-year-old lady, presented with the left hip pain, hip and knee joint in flexion with rotational component, after motor vehicle collision. All three patients were diagnosed by radiograph and were managed by closed reduction under short general anesthesia, within 3 h, 9 h, and 6 h, respectively. Thomas splint was used to immobilize the limb in all for 1 month and weight-bearing was started after 2 months from injury. Two of them were followed up to 6 months and one was lost to follow up. No evidence of avascular necrosis of femoral head or other complication related to hip dislocation was noted. Conclusion: Luxatio erecta femoris is a rare type of hip dislocation and with limited publication. The position of limb on presentation should raise the suspicion of same and diagnosis confirmed through radiological investigations. Usually, this type of dislocation can be managed with closed reduction. If closed reduction is unsuccessful, then a fracture femur or bone chip in the joint could be the cause of the difficulty. Keywords: Hip, dislocation, inferior, luxatio erecta femoris.

The interobserver reliability of first metatarsal rotational component of axial sesamoid radiographs in hallux valgus

Objective: Hallux valgus is a progressive triplanar deformity of the forefoot with an important rotational component (RC) in the first metatarsal, which has been associated with recurrence. There is controversy about using weight-bearing vs. non-weight-bearing radiographs in RC measurement. This study aims to assess interobserver reliability for RC of the first metatarsal using a non-weight-bearing sesamoid view, as well as to correlate the hallux valgus angle, intermetatarsal angle, distal metatarsal articular angle (DMAA) and sesamoid position regarding RC. Methods: An observational, cross-sectional and descriptive study was conducted with 81 feet from 48 patients (66.6% female). RC was evaluated regarding the first metatarsal proximal shaft in non-weight-bearing axial metatarsal radiographs and weight-bearing anteroposterior radiographs. Measurements were taken independently by two foot and ankle subspecialists and an orthopedic resident, all of whom were blinded. Results: Statistically significant intraclass correlations (p = 0.02) were obtained for first metatarsal RC assessment among the three observers (95%CI 0.01–0.65; Cronbach’s α =0.41) in non-weight-bearing axial metatarsal views. Significant correlations (Spearman ρ) were also found for hallux valgus angle (p = 0.04) and DMAA (p = 0.01), and non-significant correlations were found for intermetatarsal angle and sesamoid position (p > 0.05). Conclusion: The significant correlations between hallux valgus angle and DMAA for RC suggest that RC is isolated from the first metatarsal bone structure. This practical assessment method may isolate the first metatarsal head RC regarding the proximal metatarsal in the metaphyseal region and could be useful in centers where weight-bearing CT scans are not available. Level of Evidence IV; Therapeutic Studies; Case Series.

Near-Field Measurement of Six Degrees of Freedom Mining-Induced Tremors in Lower Silesian Copper Basin

The impact of seismicity on structures is one of the key problems of civil engineering. According to recent knowledge, the reliable analysis should be based on both rotational and translational components of the seismic wave. To determine the six degrees of freedom (6-DoF) characteristic of mining-induced seismicity, two sets of seismic posts were installed in the Lower Silesian Copper Basin, Poland. Long-term continuous 6-DoF measurements were conducted with the use of the R-1 rotational seismometer and EP-300 translational seismometer. In result data collection, the waveforms generated by 39 high-energy seismic events were recorded. The characteristic of the rotational component of the seismic waves were described in terms of their amplitude and frequency characteristics and were compared with translational measurements. The analysis indicated that the characteristic of the rotational component of the seismic wave differs significantly in comparison to translational ones, both in terms of their amplitude and frequency distribution. Also, attenuation of rotational and translational components was qualitatively compared. Finally, the empirical formulas for seismic rotation prediction in the Lower Silesian Copper Basin were developed and validated.

Time Scales of Submesoscale Flow Inferred from a Mooring Array

While the distribution of kinetic energy across spatial scales in the submesoscale range (1–100 km) has been estimated from observations, the associated time scales are largely unconstrained. These time scales can provide important insight into the dynamics of submesoscale turbulence because they help quantify to what degree the flow is subinertial and thus constrained by Earth’s rotation. Here a mooring array is used to estimate these time scales in the northeast Atlantic. Frequency-resolved structure functions indicate that energetic wintertime submesoscale turbulence at spatial scales around 10 km evolves on time scales of about 1 day. While these time scales are comparable to the inertial period, the observed flow also displays characteristics of subinertial flow that is geostrophically balanced to leading order. An approximate Helmholtz decomposition shows the order 10-km flow to be dominated by its rotational component, and the root-mean-square Rossby number at these scales is estimated to be 0.3. This rotational dominance and Rossby numbers below one persist down to 2.6 km, the smallest spatial scale accessible by the mooring array, despite substantially superinertial Eulerian evolution. This indicates that the Lagrangian evolution of submesoscale turbulence is slower than the Eulerian time scale estimated from the moorings. The observations therefore suggest that, on average, submesoscale turbulence largely follows subinertial dynamics in the 1–100-km range, even if Doppler shifting produces superinertial Eulerian evolution. Ageostrophic motions become increasingly important for the evolution of submesoscale turbulence as the scale is reduced—the root-mean-square Rossby number reaches 0.5 at a spatial scale of 2.6 km.

Influence of Earthquake Rotational Components on the Seismic Safety of Steel Structures

In this work a seismic analysis of structure associated with the complete description of ground motion components is performed. All earthquake excitation components corresponding to the six degrees of freedom, translational and rotational ones need to be taken into account for a realistic simulation of structural performance. The impact of the rotational components of an earthquake to the overall response of a steel structure is examined. Typically, in response to the history analyses, the seismic input is descripted by its translational component only, while the rotational components are ignored. This is because the rotational component requires special devices to be recorded in adequate detail. This is one of the reasons why this component is often ignored. With the currently available technology, such an instrument can be constructed and provide detailed records that can be used for the response history analysis of structures. The applicable design codes using a simplified response spectrum analysis accounting for rotational components is proposed and elastic design response spectra are introduced. Another reason why the rotational component was not taken into account in structural analysis is that it does not have significant effect on low-rise buildings. In this work, the analysis results in terms of response and internal forces when accounting for the rotational component is demonstrated. A case study on the response history analysis of symmetrical and non-symmetrical steel structures subjected to earthquake excitation with and without the rotational component of the excitation was performed. Numerical results show that the influence of the rotational component on the structural behaviour is important and should be taken into account in the design process.

The globular cluster population of NGC 1052-DF2: evidence for rotation

ABSTRACT Based upon the kinematics of 10 globular clusters, it has recently been claimed that the ultra-diffuse galaxy, NGC 1052-DF2, lacks a significant quantity of dark matter. Dynamical analyses have generally assumed that this galaxy is pressure supported, with the relatively small velocity dispersion of the globular cluster population indicating the deficit of dark matter. However, the presence of a significant rotation of the globular cluster population could substantially modify this conclusion. Here, we present the discovery of such a signature of rotation in the kinematics of NGC 1052-DF2’s globular clusters, with a velocity amplitude of ${\sim}12.44^{+4.40}_{-5.16}$ km s−1, which, through Bayesian model comparison, represents a marginally better fit to the available kinematic data; note that this rotation is distinct from, and approximately perpendicular to, the recently identified rotation of the stellar component of NGC 1052-DF2. Assuming this truly represents an underlying rotation, it is shown that the determined mass depends upon the inclination of the rotational component and, with a moderate inclination, the resultant mass-to-light ratio can exceed M/L ∼ 10.