Motion Measurements Research Articles

Analysis of sagittal plane cine magnetic resonance imaging for measurement of pancreatic tumor residual motion during breath hold and evaluation of gating margins used in radiotherapy treatment.

In pancreatic radiotherapy, residual tumor motion during treatment increases the risk of toxicity. Cine imaging acquired during magnetic resonance guided radiotherapy (MRgRT) enables real-time treatment gating in response to anatomical motion, which can reduce this risk; however, treatment gating can negatively impact the efficiency of treatment. This study aimed to quantify the extent of residual tumor motion during breath hold and evaluate the appropriateness of the treatment gating margins used in current clinical practice. Cine imaging acquired during pancreatic MRgRT of 11 patients on the ViewRay MRIdian was analyzed. The total duration of treatment analyzed was 12 h 13 min. Improved methods for processing and analyzing cine imaging were developed: breath holds were systematically separated with frequency analysis, residual motion was measured with consideration of both the tracking structure contour and centroid, and residual motion measurements were supported by phantom measurements of image scaling, resolution, and noise. Residual motion was measured at angles 0°, 45°, 90°, and 135° to the superior-inferior (SI) direction. Total residual motion was measured by combining directional measurements. The minimum tracking structure displacement resolvable through cine imaging was found to be 1.5mm; therefore, residual motion analysis was limited to 1.5mm spatial resolution. Total residual motion was contained within margins ±1.5, ±3, and ±4.5mm with mean percentage frequencies of 97.0%, 91.1%, and 67.8%. Most residual motion was observed in the SI direction, and significantly more residual motion was measured for the tracking structure contour than the centroid. The results demonstrate that patients are largely able to maintain breath hold positions to within a 3mm margin, thus provide evidence that supports the use of a 3mm gating margin in clinical practice. Residual motion frequently exceeded 1.5mm so a reduction in gating margin would have an undesirable impact on treatment efficiency.

Assessment of ADIS 16364 for the Examination of Ship Motions in the Free-Running Model

The ADIS 16364 instrument is frequently employed for direct measurement of ship motion on ships. However, the validation process for ADIS 16364, to assure its reliability in monitoring ship motion, has not yet been completed. The ship motion model test conducted at the hydrodynamics laboratory utilizes the free-running test technique in conjunction with the QUALISYS motion capture system and the ADIS 16364 device. The purpose of this assessment is to ascertain the instrument's appropriateness for performing ship motion testing. The ADIS device is composed of two components: an accelerometer and a gyroscope. These components are employed to quantify the acceleration of the ship's heave motion and the rotational velocity of its pitch and roll motions, respectively. Utilizing a motion capture system, the QUALISYS Motion Capture System records the motion of a ship model. The examination evaluates two discrete waves produced, comprising two cases of regular waves measuring 10 centimetres in height and 1.5 seconds in period and two cases of irregular waves measuring 16 centimetres in height and 1.75 seconds in period. The elevation motion data in the time domain is acquired from the measurements of the instrument via a wireless system. Following this, various numerical processing methods are implemented, including the moving average filter and cumulative trapezoidal numerical integration. As a result, the root mean square percentage error (RMSPE) discrepancies between the two measuring instruments for regular waves are restricted to a maximum of 5.7% for roll motion and fall below 4% for heave and pitch motions. In the results of the model test response, every movement in both the regular wave and irregular wave scenarios is the same because it does not have an RMSPE of more than 5%.

Equilibrium dynamical models in the inner region of the Large Magellanic Cloud based on Gaia DR3 kinematics

The Large Magellanic Cloud (LMC) contains complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depend on the stellar, gas, and dark matter mass distributions. Despite this complexity, simple physical models often provide valuable insights into the primary driving factors. We used Gaia Data Release 3 (DR3) to explore how well equilibrium dynamical models based on the Jeans equations and the Schwarzschild orbit superposition method are able to describe the LMC's five-dimensional phase-space distribution and line-of-sight (LOS) velocity distribution, respectively. In the Schwarzschild model, we incorporated a triaxial bar component for the first time and derived the LMC's bar pattern speed. We fit comprehensive Jeans dynamical models to all Gaia DR3 stars with proper motion and LOS velocity measurements found in the footprint of the VISTA near-infrared survey of the Magellanic System using a discrete maximum likelihood approach. These models are very efficient at discriminating genuine LMC member stars from Milky Way foreground stars and background galaxies. They constrain the shape, orientation, and enclosed mass of the galaxy under the assumption of axisymmetry. We used the Jeans model results as a stepping stone to more complex two-component Schwarzschild models, which include an axisymmetric disc and a co-centric triaxial bar, which we fit to the LMC Gaia DR3 LOS velocity field using a $ minimisation approach. The Jeans models describe the rotation and velocity dispersion of the LMC disc well, and we find an inclination angle of $ circ circ $, line of nodes orientation of $ circ circ $, and an intrinsic thickness of the disc of $q_0^d = b a (minor to major axis ratio). However, bound to axisymmetry, these models fail to properly describe the kinematics in the central region of the galaxy dominated by the LMC bar. We used the derived disc orientation and the Gaia DR3 density image of the LMC to obtain the intrinsic shape of the bar. Using these two components as input to our Schwarzschild models, we performed orbit integration and weighting in a rotating reference frame fixed to the bar, deriving an independent measurement of the LMC bar pattern speed of $ Both the Jeans and Schwarzschild models predict the same enclosed mass distribution within a radius of $6.2$\,kpc of $ Msun.

Physiologic Preoperative Knee Hyperextension Is Not Associated With Postoperative Laxity, Subjective Knee Function, or Revision Surgery After ACL Reconstruction With Hamstring Tendon Autografts.

There is concern that physiologic knee hyperextension may be associated with inferior outcomes after anterior cruciate ligament reconstruction (ACLR) using hamstring tendon (HT) autografts. To assess whether there is an association between contralateral passive preoperative knee hyperextension (≤-5°) and postoperative anterior knee laxity, subjective knee function, or revision surgery after ACLR using HT autografts. Cohort study; Level of evidence, 3. Patients without concomitant ligament injuries who underwent primary ACLR using an HT autograft at Capio Artro Clinic, Stockholm, Sweden, between January 1, 2005, and December 31, 2018, were identified. The cohort was dichotomized into the hyperextension group (≤-5°) and the no hyperextension group (>-5°) depending on preoperative contralateral passive knee extension degree. Anterior knee laxity (KT-1000 arthrometer; 134 N) was assessed preoperatively and at 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at 1, 2, and 5 years postoperatively. Patients who underwent revision ACLR at any institution in Sweden within 5 years of the primary surgery were identified in the Swedish National Knee Ligament Registry. A total of 6104 patients (53.5% male) for whom knee range of motion measurements were available were identified (hyperextension group [≤-5°]: 2350 [38.5%]; mean extension, -6.1°± 2.3° [range, -20° to -5°]; no hyperextension group [>-5°]: 3754 [61.5%]; mean extension, 0°± 1.4° [range, -4° to 15°]). There were no intergroup differences in anterior knee laxity preoperatively (hyperextension group, 3.6 ± 2.8 mm; no hyperextension group, 3.7 ± 2.7 mm; P = .24) or postoperatively (hyperextension group, 1.8 ± 2.3 mm; no hyperextension group, 1.8 ± 2.2 mm; P = .41). The only significant but nonclinically relevant intergroup differences were seen in the KOOS Symptoms subscale at the 1-year follow-up (hyperextension group, 81.4 ± 16.0; no hyperextension group, 80.3 ± 16.5; P = .03) and in the Sport and Recreation subscale at the 5-year follow-up (hyperextension group, 73.0 ± 25.6; no hyperextension group, 75.7 ± 24.3; P = .02). No other significant intergroup differences were noted preoperatively or at 1, 2, or 5 years postoperatively in any of the KOOS subscales. The overall revision ACLR rate at ≤5 years after the primary surgery was 4.9% (302 of 6104 patients). The hazard for revision ACLR in the no hyperextension group (4.5%; 170 of 3754 patients) was not significantly different from that in the hyperextension group (5.6%; 132 of 2350 patients) (hazard ratio, 0.89; 95% CI, 0.71 to -1.12; P = .34). A subsequent subanalysis showed that the hazard of revision ACLR in patients with no hyperextension was not significantly different from that of patients with ≤-10° of extension (5.8%; 27 of 467 patients) (hazard ratio, 0.91; 95% CI, 0.61 to 1.36; P = .65). Preoperative passive contralateral knee hyperextension (≤-5°) was not associated with postoperative anterior knee laxity, subjective knee function, or revision surgery ≤5 years after ACLR using HT autografts. Therefore, the presence of knee hyperextension alone should not be considered a contraindication per se for the use of HT autografts in ACLR.

Development of a 6-degrees-of-freedom measurement system using a robotic total station for a free-running model test

The measurement of a model ship's six degrees of freedom (6-DOF) using sensors such as Marvelmind beacons and robotic total stations (RTS) has previously demonstrated substantial error margins. To address these limitations, this study introduces a refined approach for accurate and reliable 6-DOF measurement through free-running model tests (FRMT). The tests were meticulously designed, with three RTS strategically positioned to meet the specific requirements of the measurement scenario. Given the potential constraints in an FRMT environment, we proposed feasible installation ranges for the RTS and prisms, ensuring the stable measurement of the model ship's 6-DOF. To achieve high-precision motion measurement, even in complex environments, we employed the prism queue algorithm, which identifies and processes overlapping or untracked prisms monitored by the RTS. The proposed methodology was validated through simulations and FRMT conducted in the ocean engineering basin of the Korea Research Institute of Ships and Ocean Engineering and by developing an actual implementation program. Comparative analysis using high-precision navigation equipment, such as fiber optic gyros, demonstrated that the method provided unbiased and stable data. Consequently, the proposed method shows significant promise as a viable alternative for precision navigation in real-world applications.

Involved-field high-dose chemoradiotherapy with respiratory motion management for esophageal squamous cell carcinoma.

We investigated the clinical outcomes of involved-field high-dose (≥66 Gy) chemoradiotherapy (CRT) combined with respiratory motion management for esophageal squamous cell carcinoma (ESCC). Patients who underwent definitive CRT for histologically confirmed ESCC in our department between 2012 and 2018 were retrospectively analyzed. Respiratory motion management strategies included breath-holding (63%) and mask immobilization (29%) based on individual measurements of respiratory tumor motion using radiographic fluoroscopy with endoscopically placed clip markers as landmarks. We evaluated patient characteristics, treatment efficacy, failure patterns, and toxicities. We enrolled 35 patients with a prescribed dose of 66-70 Gy in 33-35 fractions. The overall response rate within 6 months post-CRT was 94.3%; the median follow-up period for survivors was 43 months. The 2-year overall survival (OS), progression-free survival, and locoregional failure-free survival rates were 51.4%, 42.9%, and 42.9%, respectively. A significant difference in OS was observed between patients with and without esophageal fistulas after CRT (p = 0.002, log-rank test). Disease failure occurred in 16 patients (45.7%), including one (2.9%) with out-of-field regional nodal failure. Major grade 3 or higher toxicities included decreased white blood cell count (48.6%), neutrophil count (34.3%), and esophageal stenosis (31.4%). No grade 3 or higher cardiopulmonary toxicities were observed. Bronchial/tracheal tumor compression and a higher radiotherapy dose (70 Gy) were significantly correlated with esophageal fistulas. Involved-field high-dose CRT with respiratory motion management may be a feasible treatment option for ESCC. However, a comprehensive assessment of esophageal fistula risk is required to identify suitable candidates.

Probabilistic risk analysis of local verification of Load Model 1 in Eurocode for Soil-Steel Composite bridges in Sweden

Bridges must be designed to ensure safety for all users. At the same time, the design should be performed with an appropriate risk level. In Sweden, Soil-Steel Composite bridges (SSCB) are the most common bridge type. For SSCB, local verification of Load Model 1 in Eurocode is most often governing the design. The objective of this study was to investigate whether local verification of LM1 load case could be modified without decreasing the agreed risk level in Eurocode. Weight in motion measurements from real traffic were extrapolated with Rice formula. Monte Carlo simulations were used to simulate the 1000-year return period event to obtain the acceptable risk level as prescribed in Eurocode. The results show that the local verification of LM1 is conservative, considering the acceptable risk level in Eurocode. With a modified implementation of local verification, this paper shows that a potential saving of up to 14% in terms of economic cost and CO2-equivalents is possible. A modified implementation of local verification of LM1 in Eurocode for SSCB is proposed, which could reduce the climate impact by up to 14% associated to the construction of new SSCB in Sweden.

In-vivo left atrial surface motion and strain measurement using novel mesh regularized image block matching method with 4D-CTA

Atrial strain and motion play important roles in evaluation of stroke risks for patients with atrial fibrillation. While cardiac computed tomographic angiography (CTA) provides detailed left atrial morphology with unparallel image resolution, finding a suitable strain measurement method for CTA remains a considerable challenge. In this paper, for the first time, we introduced a mesh regularized image block matching method to estimate 3D left atrial (LA) surface strain with 4D CTA. A series of performance tests with ex-vivo phantom and in-vivo 4D-CTA data were deployed. In conclusion, our proposed method could provide reliable LA motion and strain data within limited time.

Outcomes of Arthroscopic Cortical-Button Latarjet Procedure with Minimum Five Year Follow-Up

IntroductionThe surgical treatment of anterior shoulder instability with arthroscopic cortical-button Latarjet procedure has been the subject of very few medium and long-term studies. The aim of this study was to analyze the clinical and radiological results of arthroscopic cortical-button Latarjet procedure with minimum 5 years follow-up. MethodThis is a monocentric retrospective study including 40 patients who have undergone shoulder stabilization with primary arthroscopic cortical-button Latarjet procedure and been reviewed with minimum 5 years follow-up. The average age at the time of surgery was 26.6 years (16 – 59; ± 10) and 92.5% were sporty individuals. The average ISI score was 6 points (2- 9; ± 1,6). The clinical evaluation involved active range of motion measurement, apprehension test, Rowe and Walch-Duplay scores, SSV and Net Promoter Score. Radiologically, evolution of the bone graft and degenerative arthritis of the shoulder joint were analyzed at the last follow-up. ResultsAt an average follow-up of 71 months (60 – 97; ± 12), 3 patients (7.5%) experienced recurrence as a dislocation or subluxation, which was responsible for revision in 1 case. Moreover, apprehension persisted in 6 (16%) patients. There were no significant restrictions in recovery of active ranges of motion, including external rotation. Return to sports was effective in 94.6% of cases. The average Rowe and Walch-Duplay scores were 87 points (15 - 100; ± 20) and 88 points (15 - 100; ± 19) respectively. SSV was 91% (10 – 100; ± 16) and NET Promoter Score was 9.3 points (5 – 10; ± 1,3). Radiologically, degenerative arthritis occurred in 18.7% of patients, mainly asymptomatic stage 1 (9.4%). Bone healing was acquired in 72% of cases and partial lysis of the bone block in 41%. ConclusionAt an average follow-up of 6 years, arthroscopic cortical-button Latarjet procedure effective, enabling return to sport in 95% of cases. Onset of asymptomatic arthritis seems similar to conventional techniques but justifies a more long-term follow-up.

The Magellanic Clouds Are Very Rare in the IllustrisTNG Simulations

The Large and Small Magellanic Clouds (LMC and SMC) form the closest interacting galactic system to the Milky Way, therewith providing a laboratory to test cosmological models in the local Universe. We quantify the likelihood for the Magellanic Clouds (MCs) to be observed within the ΛCDM model using hydrodynamical simulations of the IllustrisTNG project. The orbits of the MCs are constrained by proper motion measurements taken by the Hubble Space Telescope and Gaia. The MCs have a mutual separation of dMCs=24.5kpc and a relative velocity of vMCs=90.8kms−1, implying a specific phase-space density of fMCs,obs≡(dMCs·vMCs)−3=9.10×10−11km−3s3kpc−3. We select analogues to the MCs based on their stellar masses and distances in MW-like halos. None of the selected LMC analogues have a higher total mass and lower Galactocentric distance than the LMC, resulting in >3.75σ tension. We also find that the fMCs distribution in the highest resolution TNG50 simulation is in 3.95σ tension with observations. Thus, a hierarchical clustering of two massive satellites like the MCs in a narrow phase-space volume is unlikely in ΛCDM, presumably because of short merger timescales due to dynamical friction between the overlapping dark matter halos. We show that group infall led by an LMC analogue cannot populate the Galactic disc of satellites (DoS), implying that the DoS and the MCs formed in physically unrelated ways in ΛCDM. Since the 20∘ alignment of the LMC and DoS orbital poles has a likelihood of P=0.030 (2.17σ), adding this χ2 to that of fMCs gives a combined likelihood of P=3.90×10−5 (4.11σ).

Does the femoral component design modified in consideration of Asian anatomical characteristics fit better than the conventional design for Korean femora in reality?

We aimed to investigate the anatomical and clinical advantages of an Asian-specific femoral component design with a high femoral aspect ratio, compared with the conventional femoral component design. A retrospective analysis of the operation and outpatient clinic records of 239 knees operated on using an anatomically modified femoral component design (MFCD, Group A) and 153 knees operated on using a conventional femoral component design (CFCD, Group B) in Korean patients was performed. Three subgroups were created based on the mediolateral size of the two different femoral component designs. The geometric accommodation of each femoral component was assessed using intraoperatively measured femoral posterior condylar resection and posterior condylar trimming amounts. Clinical outcomes were assessed using a range of motion (ROM) and patient-reported outcome measurements. In the comparison between Groups A and B, the mean combined bilateral posterior condylar trimming (XPCT) was 2.91 [2SD: -4.12-9.94] and 1.45 [2SD: -5.89-8.80], and the median XPCT was 3 and 1.5. In the largest subgroup (subgroup 2), Groups A and B included 100 and 112 patients, all six posterior condylar resection and trimming parameters were significantly larger in Group A. Preoperative and postoperative ROM and Hospital for Special Surgery scores were similar between the two groups. Preoperative Western Ontario and McMaster Universities Arthritis Index (WOMAC) was higher in Group A. However, postoperative WOMAC was similar between the groups. Perioperative improvement in WOMAC index was significantly greater in Group B. The Asian-specific femoral component design resulted in more resection and trimming of the femoral posterior condyle than the conventional design despite it was not associated with different clinical outcomes. Surgeons should be aware of unexpected excessive posterior condylar resection and formation of large flexion gap when using femoral component design with high femoral aspect ratio.

Intrinsic Risk Factors for Noncontact Anterior Cruciate Ligament Injury in Young Female Soccer Players: A Prospective Cohort Study.

Previous studies have attempted to determine prognostic factors for predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. However, studies on risk factors for noncontact ACL injuries in Asian female soccer players are limited. To identify intrinsic risk factors for noncontact ACL injuries among young female Asian soccer players. Cohort study; Level of evidence, 2. This study evaluated 145 female Japanese soccer players for potential risk factors for noncontact ACL injury during the preseason medical assessment. In total, 25 variables were examined-including anthropometric data, joint range of motion, muscle flexibility, muscle strength, and balance measurements. Participants were monitored throughout a single season for noncontact ACL injuries diagnosed by physicians. Noncontact ACL injuries occurred in 13 knees of 13 players (9%). Lower hamstring-to-quadriceps ratio (0.44 ± 0.07 vs 0.50 ± 0.10; P = .04), greater knee extension muscle strength (3.2 ± 0.5 vs 2.7 ± 0.5 N·m/kg; P < .01), and longer playing experience (10.8 ± 3 vs 8.1 ± 4.2 years; P = .02) were significantly associated with new-onset noncontact ACL injuries in young female soccer players. No statistically significant between-group differences were found for any other variables. New-onset noncontact ACL injury in young female soccer players was significantly associated with lower hamstring-to-quadriceps ratio, greater knee extension muscle strength, and longer soccer experience. These findings will help develop strategies for preventing noncontact ACL injuries among female soccer players.

Agreement in Knee Flexion and Hip Extension Range of Motion Assessment between Digital Goniometer and Video-based Motion Tracking Technology

Precise range of motion (ROM) measurements are critical for diagnosing musculoskeletal impairments, planning treatment strategies and monitoring rehabilitation progress. This study compares the reliability and accuracy of ROM measurements using the EasyAngle electronic goniometer device and the Kemtai pose estimation video-based motion tracking software. Participants performed hip extension and knee flexion movements, with measurements taken by two examiners using both tools. The results show that both EasyAngle and Kemtai provide high inter-repetition reliability for knee flexion (ICC 0.93 and. 0.91) and hip extension (ICC 0.96 and 0.93). Kemtai generally overestimated ROM compared to EasyAngle, with relative agreement ranging from poor to good (ICC = 0.71 for knee flexion, ICC = 0.66 for hip extension). Future development and research should focus on refining digital tools like Kemtai to enhance their accuracy and reliability. Given its low cost and ease of use, Kemtai could be a useful tool for clinical practice.

Fetal and neonatal echocardiographic analysis of biomechanical alterations for the systemic right ventricle heart

Background The perinatal transition’s impact on systemic right ventricle (SRV) cardiac hemodynamics is not fully understood. Standard clinical image analysis tools fall short of capturing comprehensive diastolic and systolic measures of these hemodynamics. Objectives Compare standard and novel hemodynamic echocardiogram (echo) parameters to quantify perinatal changes in SRV and healthy controls. Methods We performed a retrospective study of 10 SRV patients with echocardiograms at 33-weeks gestation and at day of birth and 12 age-matched controls. We used in-house developed analysis algorithms to quantify ventricular biomechanics from four-chamber B-mode and color Doppler scans. Cardiac morphology, hemodynamics, tissue motion, deformation, and flow parameters were measured. Results Tissue motion, deformation, and index measurements did not reliably capture biomechanical changes. Stroke volume and cardiac output were nearly twice as large for the SRV compared to the control RV and left ventricle (LV) due to RV enlargement. The enlarged RV exhibited disordered flow with higher energy loss (EL) compared to prenatal control LV and postnatal control RV and LV. Furthermore, the enlarged RV demonstrated elevated vortex strength (VS) and kinetic energy (KE) compared to both the control RV and LV, prenatally and postnatally. The SRV showed reduced relaxation with increased early filling velocity (E) compared prenatally to the LV and postnatally to the control RV and LV. Furthermore, increased recovery pressure (ΔP) was observed between the SRV and control RV and LV, prenatally and postnatally. Conclusions The novel hydrodynamic parameters more reliably capture the SRV alterations than traditional parameters.

Campanacci Grade 2 or 3 Giant Cell Tumor of the Phalanges: En Bloc Resection and Matched Nonvascularized Toe Phalangeal Transfer

The goal of the study was to assess the result of en bloc resection and matched nonvascularized toe phalangeal transfer in Campanacci grade 2 or 3 giant cell tumors of the phalanges. Seven patients with Campanacci grade 2 and 3 phalangeal giant cell tumors were treated by en bloc resection and matched nonvascularized toe phalangeal transfer between June 2004 and May 2021. The patients were followed up by X-rays, Patient-Rated Hand and Wrist scores, Foot Function Index, Quick Disabilities of the Arm, Shoulder, and Hand questionnaire, and total active motion measurements. The minimum follow-up was 18 months (range: 18-230 months; mean: 110 ± 81). There were three males and four females, with age ranging from 13 to 48 years (mean: 24.14 ± 11.74). The right:left hand ratio was 3:4. The thumb was involved in one patient, the index finger in two, the middle finger in one, and the ring finger in three patients. The mean total active motion was 201.70 (range: 190°-240°). The mean patient-rated hand and wrist score was 15.2 (range: 10-35). The mean quick disabilities of the arm, shoulder and hand questionnaire score was 1.3 (range: 0-9). The mean foot function index on follow-up was 2.86 (range: 2-3). There was no tumor recurrence. One patient had a pathological fracture with resultant shortening of the finger on follow-up. In our series en bloc resection and matched nonvascularized toe phalangeal transfer resulted in a functional tumor-free digit with a low complication rate and no recurrences. Therapeutic V.

Overdose Detection Among High-Risk Opioid Users Via a Wearable Chest Sensor in a Supervised Injecting Facility: Protocol for an Observational Study.

Opioid overdose is a global health crisis, affecting over 27 million individuals worldwide, with more than 100,000 drug overdose deaths in the United States in 2022-2023. This protocol outlines the development of the PneumoWave chest biosensor, a wearable device being designed to detect respiratory depression in real time through chest motion measurement, intending to enhance early intervention and thereby reduce fatalities. The study aims to (1) differentiate opioid-induced respiratory depression (OIRD) from nonfatal opioid use patterns to develop and refine an overdose detection algorithm and (2) examine participants' acceptability of the chest biosensor. The study adopts an observational design over a 6-month period. The biosensor, a small device, will be worn by consenting participants during injecting events to capture chest motion data. Safe injecting facilities (SIF) in Melbourne, Victoria (site 1), and Sydney, New South Wales (site 2), which are legally sanctioned spaces where individuals can use preobtained illicit drugs under medical supervision. Each site is anticipated to recruit up to 100 participants who inject opioids and attend the SIF. Participants will wear the biosensor during supervised injecting events at both sites. The biosensor will attempt to capture data on an anticipated 40 adverse drug events. The biosensor's ability to detect OIRD will be compared to the staff-identified events that use standard protocols for managing overdoses. Measurements will include (1) chest wall movement measured by the biosensor, securely streamed to a cloud, and analyzed to refine an overdose detection algorithm and (2) acute events or potential overdose identified by site staff. Acceptability will be measured by a feedback questionnaire as many times as the participant is willing to throughout the study. As of April 2024, a total of 47 participants have been enrolled and data from 1145 injecting events have already been collected, including 10 overdose events. This consists of 17 females and 30 males with an average age of 45 years. Data analysis is ongoing. This protocol establishes a foundation for advancing wearable technology in opioid overdose prevention within SIFs. The study will provide chest wall movement data and associated overdose data that will be used to train an algorithm that allows the biosensor to detect an overdose. The study will contribute crucial insights into OIRD, emphasizing the biosensor's potential step forward in real-time intervention strategies. DERR1-10.2196/57367.

Sufficiency assessment of intensity measures for natural and spectral-matched ground motion records

A correct Intensity Measure (IM) selection is essential for Performance-Based Earthquake Engineering (PBEE) applications, as any probabilistic seismic demand model (PSDM) depends significantly on the IM. If a single IM can describe the complexity of the corresponding ground motion record, it can be defined as sufficient in an absolute sense. However, this is unlikely because a single number should be able to inform on the frequency content, the amplitude, the duration, the energy content, etc. For this reason, literature studies have defined sufficiency in a relative sense to investigate whether one IM is more sufficient (i.e., more informative) than another in predicting the structural response. This work explores the relative sufficiency of eight scalar IMs through Nonlinear Response History Analyses (NRHAs) using two sets of 20 pairs of ground motion records. Both sets are spectrum-compatible and consist of unscaled natural and spectral-matched records. Also, both Cloud and Incremental Dynamic Analysis procedures are used. This study demonstrates that Cloud analysis cannot be used in its conventional form to study sufficiency when spectral-matched accelerograms are used. When natural accelerograms are employed, the results clearly indicate the existence of a sufficient IM among those selected. Conversely, it is more difficult to define the relative sufficiency of the IMs for spectral-matched records because the operation of record adjusting leads to similar structural demands. This result could question either the validity of using spectral-matched accelerograms for PBEE due to the lack of aleatory variability in the structural demand or the necessity of having a sufficient IM when a PSDM is fitted in a PBEE analysis using spectral-matched accelerograms.

Effects of Tear-Associated Scapula Shape on the Stabilizing Potential of Glenohumeral Muscles

Glenohumeral muscles stabilize the humerus by providing compressive forces directed into the glenoid or by resisting opposing forces from larger muscles like the deltoid. Scapula shape is correlated to rotator cuff tear likelihood and previous research found that tear-associated shapes shift the supraspinatus’ line-of-action (LOA) anteriorly, potentially inhibiting its stabilizing potential. We predicted that the tear-associated scapula shape would cause an anterior shift in all glenohumeral muscles’ LOA. We expanded previous finite element models and computational scripts to compute the stability ratios of the teres major, teres minor, infraspinatus, supraspinatus and subscapularis on tear-associated and non-tear control scapulas. We identified insertion and attachment points for each muscle and created respective straight muscle meshes in Matlab. Then, we wrapped those meshes around the scapula and humerus surfaces and simulated an arm-raising motion in the open-source modelling package, Artisynth. In Matlab, we computed the muscle LOAs and their anterior-posterior (AP) and superior-inferior (SI) stability ratios, which describe how muscles tend to pull on the humerus relative to the glenoid. We found that the mean AP stability ratios of all five glenohumeral muscles were higher in the tear-associated scapula shape compared to the control shape, indicating an anterior shift in the muscles’ LOA. Aside from the teres minor, all other muscles exhibited slightly larger SI ratios for the tear-associated scapula shape, indicating a shift superiorly in their LOA. The tear-associated scapula shape may impact certain glenohumeral muscles’ ability to stabilize the humerus, placing higher demand on posterior fibres, subscapularis and teres major to maintain anterior stability. These findings indicate a potential injury mechanism caused by scapula shape and may help to inform rotator cuff tear prevention and rehabilitation. This method can also be applied to in vivo measurements of shoulder motions and bones to provide precise, patient-specific information on rotator cuff stabilizing potential.

Preoperative rotator cuff fatty infiltration and muscle atrophy do not negatively influence outcomes following anatomic total shoulder arthroplasty

BackgroundAnatomic total shoulder arthroplasty (TSA) is an effective surgical option for the treatment of primary glenohumeral osteoarthritis (GHOA) with an intact rotator cuff. While an intact rotator cuff is essential to the success of TSA, little is known about how preoperative rotator cuff muscle quality may impact clinical outcomes. In this study, we sought to determine the effects of rotator cuff fatty infiltration (FI) and muscle atrophy (MA) on clinical outcomes following TSA. MethodsA retrospective review of a prospectively maintained, single-surgeon registry was used to identify patients undergoing TSA for GHOA between April 2015 and March 2020. Patients were included if they had preoperative magnetic resonance imaging available, an intact rotator cuff, and complete preoperative and minimum 2-year postoperative patient-reported outcome measures (PROMs) and active range of motion (ROM) measurements. Preoperative MA and FI of the rotator cuff were assessed on magnetic resonance imaging by measuring muscle cross-sectional area and using the Goutallier classification system, respectively. Pearson’s correlation was used to determine any relationship between MA and clinical outcomes. Univariate analysis was used to compare clinical outcomes of patients with moderate-to-severe FI to those with minimal-to-mild FI. ResultsThere were 163 shoulders from 154 patients with a mean age of 62.5 (standard deviation = 7.4) and a mean follow-up of 2.9 years (standard deviation 1.2) that met inclusion criteria. Rotator cuff muscle area was not correlated with any preoperative or postoperative ROM or PROMs (P > .05). However, the ratio of infraspinatus and teres minor (posterior cuff) to subscapularis muscle area was minimally negatively correlated with change in Single Assessment Numerical Evaluation (r = −0.171, P = .029) and change in internal rotation (r = −0.207, P = .008), although the clinical relevance is unclear. No significant differences in preoperative ROM or PROMs were found between patients with minimal-to-mild and moderate-to-severe FI (P > .05). ConclusionPreoperative rotator cuff muscle volume and FI do not impact clinical outcomes following TSA in patients with GHOA and intact rotator cuffs. TSA remains a viable surgical treatment for individuals with GHOA and an intact rotator cuff, provided the MA and FI are not so severe that a patient may be indicated for another type of treatment.

Hubble Space Telescope proper motions of Large Magellanic Cloud star clusters

We present proper motion (PM) measurements for a sample of 23 massive star clusters within the Large Magellanic Cloud using multi-epoch data from the Hubble Space Telescope (HST). We combined archival data from the ACS/WFC and WFC3/UVIS instruments with observations from a dedicated HST programme, resulting in time baselines between 4.7 and 18.2 yr available for PM determinations. For bright well-measured stars, we achieved nominal PM precisions of 55 μas yr−1 down to 11 μas yr−1. To demonstrate the potential and limitations of our PM data set, we analysed the cluster NGC 1850 and showcase a selection of different science applications. The precision of the PM measurements allows us to disentangle the kinematics of the various stellar populations that are present in the HST field. The cluster has a centre-of-mass motion that is different from the surrounding old field stars and also differs from the mean motion of a close-by group of very young stars. We determined the velocity dispersion of field stars to be 0.128 ± 0.003 mas yr−1 (corresponding to 30.3 ± 0.7 km s−1). The velocity dispersion of the cluster inferred from the PM data set most probably overestimates the true value, suggesting that the precision of the measurements at this stage is not sufficient for a reliable analysis of the internal kinematics of extra-galactic star clusters. Finally, we exploit the PM-cleaned catalogue of likely cluster members to determine any radial segregation between fast and slowly-rotating stars, finding that the former are more centrally concentrated. With this paper, we also release the astro-photometric catalogues for each cluster.