Axial Alignment Research Articles

Depressive symptoms and axial motor disorders in individuals with Parkinson's disease: a cross-sectional study.

Depression is an important nonmotor symptom of Parkinson's disease (PD) and has been associated with the motor symptoms in these individuals. To determine whether there are relationships between depressive symptoms and abnormalities in axial postural alignment and axial motor deficits, especially postural instability, and trunk rigidity in PD. In this cross-sectional study, 65 individuals were evaluated using the Beck Depression Inventory-II (BDI-II) for the analysis of depressive symptoms and underwent a postural assessment of head, trunk, and hip sagittal alignment through computerized photogrammetry. The MDS-UPDRS was used to assess clinical aspects of PD, the Trunk Mobility Scale was used to assess axial rigidity, and the MiniBESTest to assess balance. To determine the relationship between depressive symptoms and postural alignment, multiple linear regression analysis was performed. The participants with depressive symptoms had more severe motor deficits as well as greater trunk rigidity and worse postural instability (p < 0.05). When the postural angles were compared between men and women using Student's t-test, it was found that men had greater flexion angles of the head (p = 0.003) and trunk (p = 0.017). Using multiple linear regression analysis corrected for the age and sex of the participants, we verified that the anterior trunk inclination was significantly larger in the PD population with depressive symptoms (R2 = 0.453, β = 0.116, and p = 0.045). PD individuals with depressive symptoms have more severe flexed trunk posture, mainly in older men. Additionally, more severe depressive symptoms are associated with worsening postural instability, trunk rigidity and motor deficits in this population.

Quantitative explanation of the difference in AC magnetization curves between suspended and immobilized magnetic nanoparticles for biomedical application

We study the difference in AC magnetization (M−H) curves between suspended and immobilized magnetic nanoparticles (MNPs). We use three commercial MNP samples that are often used for biomedical application. First, we measure the hysteresis area of the AC M−H curve, A, when the amplitude of the excitation field, Hac, is changed. The A vs Hac curve is compared with previously obtained analytical results by taking account of the MNP size distribution in the sample. We show that they quantitatively agree for both suspended and immobilized samples. From the comparison, we clarify the mechanism that determines the AC M−H curve of a suspended sample. For high Hac, the Néel relaxation becomes dominant in the suspended sample, and alignment of easy axes caused by the AC field increases the hysteresis loss compared to the immobilized case. The effect of Brownian relaxation in the suspended sample increases with decreasing Hac and gives additional loss at low field. The portion of Néel-relaxation- and Brownian-relaxation-dominant MNPs in the sample is quantitatively evaluated. We also clarify the difference in harmonic signals between suspended and immobilized samples. Finally, we discuss the condition for the MNP parameters and excitation field that determines the dominant relaxation mechanism in a suspended sample.

Robot-assisted assessment of the effects of self-aligning mechanism on the wrist passive range of motion

Axis alignment between human and robot has been a research hotspot in wearable rehabilitation robots and has a significant effects on full natural ranges of motion (ROM) during robot-assisted training exercises. Self-alignment mechanism (SAM) has been extensively applied on the rehabilitation robots to adaptively compensate the axis misalignment between human anatomic and robot mechanical joints. However, the effects of the SAM on the wrist ROM have not been definitely assessed. In this study, we implemented a SAM on a wrist rehabilitation device (WReD II), and the SAM was specially designed to be locked or unlocked to achieve self-alignment function or not according to demands. To assess the effects of SAM on the wrist passive ROM of extension/flexion (E/F), passive training experiments involving 8 healthy participants were conducted by locking or unlocking the SAM respectively. Surface Electromyography (sEMG) was applied to monitor muscle activity during experiments. During the experiments, the wrist passive ROM were measured by applying the robot-assisted assessment technique. Preliminary results show that the means of the passive ROM have a maximum increase of 19.78° in the case with SAM unlocked when compared to the case with SAM locked. Statistical results indicated high test-retest reliability of the passive ROM measurements with intraclass correlation coefficient ICC (2,1) more than 0.82, and standard error of measurement (SEM) less than 3.2°. These findings suggest that the implement of SAM on the rehabilitation robots has great potentials due to its feasibility and reliability to obtain larger natural passive ROM.

Validating Foot Center Axis and Ankle Rotation using Weight-Bearing CT

Category: Ankle; Ankle Arthritis Introduction/Purpose: Even as its popularity increases, there remain many unanswered questions regarding total ankle arthroplasty. One debate considers the proper rotation of the talar component to restore native, non-osteoarthritic anatomy. The foot center axis is a unique anatomic concept that considers the position of the native foot relative to the ankle. The present pilot study sought to evaluate the reproducibility of axial alignment measurements, including the foot center on weight-bearing CT in patients without ankle osteoarthritis. Methods: Following IRB approval, charts were reviewed to identify patients without ankle osteoarthritis, trauma or other deformity who received a weightbearing CT scan. A pilot group of n=8 patients were included for a total of n=10 limbs. Average age was 50.1 +/- 14 and there were 38% female patients. All measurements were made on MPR (multiplanar reformation) axial reconstructions. Cobb angle measurements between the anatomic foot center, the second, the fourth metatarsal and the gutter bisector or medial gutter line were recorded by n=4 observers. Intraclass correlation (ICC) was produced using a two-way random effects model with absolute agreement and other statistical testing was performed by IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY. Results: The average gutter bisector angle was 6.2 deg +/- 2.0 and the average angle between the medial base of the 1st metatarsal head, lateral base of the 5th metatarsal head and the posterior calcaneus was 33.0 deg +/- 2.6. Amongst the observers, the ICC for these landmarks were 0.95 and 0.96 respectively. The average cobb angle measurement between the gutter bisector angle and the second metatarsal was 8.3 deg +/- 7.3, with a corresponding ICC of 0.96. The average cobb angle measurement between the gutter bisector angle and the anatomic foot center was 5.6 deg +/- 4.3 and the average cobb angle measurement between the medial gutter line and the anatomic foot center was 6.23 deg +/- 6. Amongst the observers, the ICC for these measurements were 0.81 and 0.81 respectively. Conclusion: In a small pilot study of patients without osteoarthritis who underwent weight-bearing CT scans there was good (ICC&gt;0.75-0.90) to excellent (ICC&gt;0.90) agreement amongst observers for measurements of foot center axis and ankle rotation. These findings validate the reproducibility and agreement of these manually constructed measurements for assessing the relationship between the foot center axis and ankle rotation. Future studies will expand upon the use of these measurements to define non-arthritic anatomy. The anatomic foot center may be a useful guide for establishing intra-operative foot orientation when performing total ankle arthroplasty.

Comparison of Foot Center Axis and Ankle Rotation using Weight-Bearing CT

Category: Ankle; Ankle Arthritis Introduction/Purpose: Even as its popularity increases, there remain many unanswered questions regarding total ankle arthroplasty. One debate considers how best to restore proper rotation of the talar component relative to native, non- osteoarthritic anatomy. At present, two common schools of thought are to parallel the talar component rotation with the medial gutter line or to choose a line that bisects the gutters. These axis' are then considered with respect to a chosen foot axis, often defined by the second metatarsal or second toe clinically. The present study sought to define the foot center axis relative to the ankle on weight-bearing CT in patients without ankle osteoarthritis to inform talar component positioning in total ankle arthroplasty. Methods: Following IRB approval, charts were reviewed to identify patients without ankle osteoarthritis, trauma or other deformity who received a weightbearing CT scan. A pilot group of n=34 patients were included for a total of n=50 limbs. Average age was 50.3 +/- 7 and there were = 54% female patients. All measurements were made on MPR (multiplanar reformation) axial reconstructions. Cobb angle measurements between the anatomic foot center, the second, the fourth metatarsal and the gutter bisector or medial gutter line were recorded. Statistical analysis was performed by IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY. Results: The mean gutter bisector angle was 5.7 deg +/- 2.0. The mean cobb angle between the anatomic foot center and the medial gutter line was 6.1 deg +/- 4.4 and between the anatomic foot center and gutter bisector was 6.3 deg +/- 4.8, there was no statistical difference between measurements (p=0.62, Table 1). The mean cobb angle between the second metatarsal and the gutter bisector was 9.9 deg +/- 6.8, whereas the mean cobb angle between the fourth metatarsal and the gutter bisector was 7.5 deg +/- 5.2, which was not statistically significant (p=0.053). There was no statistical difference between mean cobb angle measurements between the anatomic foot center and the gutter bisector and the fourth metatarsal and the gutter bisector (p=0.243), but there was statistical difference between mean cobb angle measurements of the second metatarsal and the gutter bisector and the anatomic foot center and the gutter bisector (p=0.003). Conclusion: The axial alignment of the foot center axis relative to the ankle in patients without deformity or osteoarthritis is most collinear with the medial gutter line. In general, the axial alignment of the ankle joint relative to the foot in patients without osteoarthritis tends towards &lt;10 degrees of difference on weight-bearing CT, regardless of method chosen. Due to both the consistency of measure and reproducibility of measure on pre-operative weight-bearing CT, the anatomic foot center may be a useful guide for establishing intra-operative foot orientation when performing total ankle arthroplasty.

Does a 1st Metatarsophalangeal Fusion in a Patient with Pes Planus Improve the Pes Planus Deformity? A Retrospective Case Series

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: A pes planus deformity is a pathology relating to the loss of normality of the complex interaction of the bones and joints of the foot resulting in a flattening of the medial longitudinal arch with or without abduction of the midfoot. The distal aspect of the medial longitudinal arch can be a feature of the deformity. The fusion of the 1st metatarsophalangeal joint (MTPJ) is a common operation. In patients with concomitant pes planus deformity, it is unknown if reducing and stabilising the distal aspect of the medial ray through a 1st MTPJ fusion can subsequently improve the pes planus deformity. We sought to analyse the pes planus deformity pre and post 1st MTPJ fusion with the null hypothesis that there was no difference. Methods: We identified patients who had undergone 1st MTPJ fusion using our electronic database from January 2011 to October 2021. To meet the inclusion criteria, cases required pre- and post-operative weightbearing plain radiographs, with a Meary's angle of &gt;4 degrees on pre-operative imaging. Routine pes planus measurements were undertaken by 2 independent observers. Pre- and post-operative measurements were tested for significant change using Wilcoxon Signed Rank Test or Paired T-Test depending on the normality testing of the data. Routine demographic data was also collected. Data was analysed using IBM SPSS v.27. Results: Following radiographic analysis, 25 feet fitted the inclusion criteria. The mean patient age was 63 years. There was no pre-operative correlation between Meary's angle and the hallux valgus angle (Kendall's tau p=.441). Pre-operatively, Meary's line broke at the talo-navicular and navicular-cuneiform joints in 12 cases each; the remaining case broke at the tarsal-metatarsal joint. A statistically significant improvement between the pre- and post-operative measurements was identified in Meary's angle, calcaneal pitch angle, talo-navicular coverage angle, intermetatarsal angle and talo-navicular angle (see table). Significant changes were also noted in the medial cuneiform height (mean increase of 2.74mm; p=.022). A post-operative Meary's angle of &lt;4°was only achieved in 4/25 (16%) of cases. Of the remaining 21 cases, the point at which Meary's line broke moved proximally one joint in 4 and distally one joint in 3 cases; it remained at the same joint in 14 cases. Conclusion: Our results suggest that 1st MTPJ fusion improves axial alignment of the foot as well as reducing Meary's angle by a statistically significant amount, although diagnostic criteria for pes planus remained in most cases.

Analysis of Corrective Distal Tibio-Fibular Osteotomy for Medial Compartment Osteoarthritis and Evaluation of Prognostic Factors: Consecutive 67 Cases in One Center

Category: Ankle Arthritis; Ankle; Arthroscopy Introduction/Purpose: A supramalleolar osteotomy is a joint-sparing procedure that can change the mechanical axis load on the ankle joint in the coronal-sagittal planes. Restoration of the axial alignment allows for redistribution of loads to the less affected area of articular cartilage, slowing down or even stopping further articular degeneration. It has been reported that supramalleolar osteotomy has a useful effect in asymmetric varus ankle and medial compartment osteoarthritis, but as far as we know there are not many papers conducted in one center for large cases based study. In our paper, we analyzed the results of multiple cases (67 cases) of supramalleolar osteotomy surgical procedure performed in our center and make insight about prognostic factors like high talar tilt and takakura stage. Methods: From August 2007 to May 2020, a retrospective study was conducted on 67 ankles which underwent distal tibio-fibular osteotomy due to medial compartment osteoarthritis and asymmetric varus ankle in our center. The articular cartilage was evaluated simultaneously with the distal tibio-fibular osteotomy through arthroscopy exam intraoperatively. The mean age was 58.6 years(range 37-73 years). American Orthopaedic Foot &amp; Ankle Society (AOFAS) ankle-hindfoot score, Visual analog scale (Vas) pain score, Range of motion (ROM) and patient satisfaction were used for functional evaluations. Ankle osteoarthritis was classified by Takakura stage, and the tibial anterior surface angle (TAS), tibial lateral surface angle (TLS) and talar tilt angle were measured for radiological evaluations. And, groups were divided according to the Takakura stage, and whether there were significant differences in the measured values was compared. Results: When Preop IIIB and Preop II, IIIA groups were compared, last fu AOFAS score and Pain vas score showed no significant difference. Talar tilt angle showed significant higher value in Preop IIIB group(p&lt;0.05). And TAS angle showed bigger correction in Preop IIIB group with borderline difference. (p=0.07) It seems that overcorrected TAS angle came out to maximize the effect of load transfer to laterally intra-operatively. And it is thought that the overcorrected TAS angle had a good effect on the clinical outcome. When Preop IIIB group were divided stage improved group with not improved group and compared each other, last fu AOFAS score and ROM showed worse results in Postop IIIB group significantly. (p&lt;0.05) Talar tilt showed higher value in Postop IIIB group on preop with borderline differences.(p=0.06) TAS angle showed no significant differences.(p=0.58) Conclusion: We performed SMO for stage IIIB medial ankle OA with significant TAS overcorrection, and achieved favorable clinical outcomes (AOFAS 85.1) when compared with preop stage IIIA group (AOFAS 85.6). Postop stage IIIB group showed higher preop talar tilt angles with poor AOFAS score when compared with postop takakura stage improved group (10.7 and 7.6). Many preop IIIB cases are found to be good candidate for SMO, but skillful selection for SMO is required for good results.

Influence of acousto-optic frequency shifter's thermal-induced birefringence on laser frequency-shifted feedback system

The acousto-optic frequency shifter (AOFS) is the key component of the laser frequency-shifted feedback (LFSF) system, and its thermal-induced birefringence (TIB) seriously affects the stability of the system. In this paper, the influence of the AOFS's TIB on LFSF system is analyzed, and the method of suppressing this influence is proposed. The theoretical model of LFSF considering the AOFS's TIB is established, and the influence on both amplitude and phase of frequency-shifted signal is analyzed. When the AOFS starts working, its TIB effect is obvious due to the accumulation of working heat, which makes the polarization state of its diffraction light change dynamically in most cases. The laser feedback imaging system and laser feedback displacement measurement system are built separately to evaluate the amplitude and phase stability. By principal axis alignment or quasi-common-path compensation, the amplitude variation, phase fluctuation, phase jump and phase temperature drift caused by the AOFS's TIB can be eliminated or suppressed. This study improves the startup stability and anti-ambient temperature interference ability of the LFSF system, which also has guiding significance to other heterodyne interference systems.

Numerical and experimental flow investigation using ultrasonic PIV for optimizing mechanically agitated lab-scale anaerobic digesters

In this article, a non-invasive ultrasonic flow field measurement method is studied to investigate its applicability to resolve fluid flow in bio- and chemical engineering reactors. In detail, the proposed flow field investigation method is applied to mechanically agitated lab-scale reactors for the validation of anaerobic digester mixing simulations. Two reactors with different geometries, which are cold models of real-life anaerobic digesters, are studied. Since conventional non-invasive flow field measurement techniques are not suitable for the investigated reactor geometries, the applicability of ultrasonic measurement is demonstrated. The experimental results are compared to Computational Fluid Dynamics (CFD) simulations using the Finite Volume Method with multiple reference frames to account for the stirrer-induced mixing. It is shown that ultrasonic measurement is an easily applicable non-invasive method for resolving flow fields of opaque fluids found in chemical, mechanical and biological engineering. The study highlights the benefits of the non-invasive measurement approach and also demonstrates the suitability of this flow measurement technique for further applications such as the optimization of the mixing time characteristics of paints and coatings or silicone production. The resolved flow fields are in accordance with numerical reference results with minor deviations of up to 9% for velocity measurements aligned with the main axis of the ultrasound probe. The validated CFD model can be used as a template for modelling similar chemical engineering processes where the mixing time characteristic is critical. It is further shown that the accuracy of this flow measurement method decreases with increased offsets from the main axis. In addition to the axis alignment, the impact of different fluid properties and reactor geometries is also discussed.

Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure

Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. Statement of significanceDamage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.

Residual elbow instability in children with posterior or postero-lateral elbow dislocation.

The purpose of this study is to evaluate the incidence and the severity of residual elbow instability in children treated for posterior (PED) or postero-lateral (PLED) elbow dislocation. This retrospective study included all children younger than 14 years of age with a confirmed diagnosis of acute post-traumatic elbow dislocation (ED). Subjective data such as perceived pain, stiffness and impact of daily activities, and objective data such as skin lesions, surgical-site infections, and range of motion were recorded. All patients underwent the milking test, the chair sign test (CST) and the Drawer test (DT). The functional status has been rated according to the Mayo Elbow Performance Score (MEPS) and the Roberts criteria (RC). Radiographs of the injured arm were performed at the last follow-up visit to evaluate axial alignment, growth disturbances, osteoarthrosis, heterotopic calcifications, and the presence of loose intra-articular bodies. Nineteen patients with a mean age of 9 years and 5 months at the time of injury were available for review. Six patients had PED (31.6%) and 13 PLED (68.4%); in five cases (26.3%) the dislocation was simple and in 14 cases (73.7%) it was complex. None of the patients complained of subjective symptoms of elbow instability, although 2 patients had positive CST, and one of them also had positive milking test. RC and MEPS ranged from good to excellent in all patients. Clinical examination with multiple stability tests is important to detect residual elbow instability in children treated for ED as functional scores alone may underestimate the clinical picture.

Functional alignment achieves a more balanced total knee arthroplasty than either mechanical alignment or kinematic alignment prior to soft tissue releases

PurposeTotal knee arthroplasty with functional alignment uses pre-resection balancing to determine component position within the soft tissue envelope to achieve balance and restoration of native joint obliquity. The purpose of this study was to assess the balance achievable with a mechanical axis alignment and kinematic axis alignment plan, and the subsequent balance achievable after adjustment of the component position to functional alignment.MethodsA prospective cohort of 300 knees undergoing cruciate retaining total knee arthroplasty were included in this study. Of these, 130 were initially planned with mechanical alignment (MA) and 170 with kinematic alignment (KA). Maximal stressed virtual gaps were collected using an optical tracking software system. The gaps were measured medially and laterally in flexion and extension. Following assessment of balance, implant position was adjusted to balance the soft tissues in functional alignment (FA) and the maximal gaps reassessed. Gaps were considered to be balanced when within 2 mm of equality. Incidence of balance within each cohort was compared to independent samples proportions test.ResultsFunctional alignment obtained significantly better balance in extension, medially and overall than both MA and KA alignment without soft tissue release (p < 0.001). Overall balance was observed in 97% of FA knees, 73% of KA knees and in 55% of MA knees. The difference between KA and MA was also significant (p = 0.002). Whilst there was no difference observed in balanced achieved or limb alignment when FA was planned with either MA or KA, the joint line obliquity was maintained with an initial KA plan.ConclusionFunctional alignment more consistently achieves a balanced total knee arthroplasty than either mechanical alignment or kinematic alignment prior to undertaking soft tissue release. Utilising an individualised KA plan allows FA to best achieve the stated goals of maintaining joint line plane and obliquity.Level of evidenceLevel III: retrospective cohort study.

EVALUATION OF FUNCTIONAL AND RADIOLOGICAL OUTCOMES OF ADULT DIAPHYSEAL FRACTURES OF BOTH BONE FOREARM OPERATED WITH PLATING OR NAILING

Background: Fractures of both radius and ulna are one of the most common fractures in adults in upper extremity .It is essential to regain length, apposition, axial alignment and normal rotational alignment while treating diaphyseal fractures of the radius and the ulna to gain good range of pronation and supination. Mal-union and nonunion occur more frequently because of the difculty in reducing and maintaining the reduction of two parallel bones in the presence of the pronating and supinating muscles that have angulating and rotational inuences). There lies a controversy with respect to choice of treatment as per chances of infection, duration of healing and the surgeon preferences. The present study is thus undertaken to compare functional outcome and radiological union using two different surgical modalities i.e. Dynamic Compression Plating and Intramedullary nailing. All adult patients(&gt;12years) with Materials And Methods: diaphyseal fractures of both bones of forearm presenting to A&amp;E department, requiring operative intervention were selected and were included in an interventional and comparative prospective cohort study.A total of 48 subjects fullling eligibility criteria were randomly divided into four groups A, B, C and D (12 each) using random number table. Most cases with Results: excellent to good functional outcome was seen in both bones plating group (100%) followed by hybrid techniques. Incidence of mal-union was seen in 2 cases each of both bone nailing and ulnar plating and radius nailing and in 1 case of radius plating and ulnar nailing. Among the four different xation methods for treating both bone diaphyseal forea Conclusion: rm fractures in adults, the method with both bone i.e. ulna and radius plate xation showed good stability in biomechanics, the lowest complication rate and best functional recovery outcomes

Enhancing Horizontal Ratio of Transition Dipole Moment in Homoleptic Ir Complexes for High Outcoupling Efficiency of Organic Light-Emitting Diodes.

The light-emitting dipole orientation (EDO) of a phosphorescent emitter is a key to improving the external quantum efficiency (EQE) of organic light-emitting diodes (OLEDs) without structural modification of the device. Here, four homoleptic Ir complexes as a phosphorescent emitter are systematically designed based on the molecular structure of tris(2-phenylpyridine)iridium(III) (Ir(ppy)3 ) to control the EDO. Trimethylsilane, methyl, 2-methylpropyl, and cyclopentylmethyl group substituted to pyridine ring of the ligand contribute to the improvement of the EDO from 76.5% for Ir(ppy)3 to 87.5%. A linear relationship between the EDO and the aspect ratio (geometric anisotropy factor) is founded, implying the importance of the effective area for the nonbonding force between host and dopant molecules. Also, it is investigated that the EDO enhancement mainly originates from the vertical alignment of the C3 axis of molecule in the substrate axis rather than the change in the direction of the transition dipole alignment in the molecular axis. The optical simulation reveals that the outcoupling efficiency of phosphorescent OLEDs adopting new dopants reaches 38.4%. The green OLEDs exhibiting 28.3% of EQE, 103.2cdA-1 of current efficiency, and 98.2lmW-1 of power efficiency are demonstrated, which is understood to have little electrical loss.

Tidal excitation of the obliquity of Earth-like planets in the habitable zone of M-dwarf stars

Close-in planets undergo strong tidal interactions with the parent star that modify their spins and orbits. In the two-body problem, the final stage for tidal evolution is the synchronisation of the rotation and orbital periods, and the alignment of the planet spin axis with the normal to the orbit (zero planet obliquity). The orbital eccentricity is also damped to zero, but over a much longer timescale, that may exceed the lifetime of the system. For non-zero eccentricities, the rotation rate can be trapped in spin–orbit resonances that delay the evolution towards the synchronous state. Here we show that capture in some spin–orbit resonances may also excite the obliquity to high values rather than damp it to zero. Depending on the system parameters, obliquities of 60º–80º can be maintained throughout the entire lifetime of the planet. This unexpected behaviour is particularly important for Earth-like planets in the habitable zone of M-dwarf stars, as it may help to sustain temperate environments and thus more favourable conditions for life.

Ultrafast electron diffraction from transiently aligned asymmetric top molecules: Rotational dynamics and structure retrieval.

Ultrafast electron diffraction (UED) from aligned molecules in the gas phase has successfully retrieved structures of both linear and symmetric top molecules. Alignment of asymmetric tops has been recorded with UED but no structural information was retrieved. We present here the extraction of two-dimensional structural information from simple transformations of experimental diffraction patterns of aligned molecules as a proof-of-principle for the recovery of the full structure. We align 4-fluorobenzotrifluoride with a linearly polarized laser and show that we can distinguish between atomic pairs with equal distances that are parallel and perpendicular to the aligned axis. We additionally show with numerical simulations that by cooling the molecules to a rotational temperature of 1 K, more distances and angles can be resolved through direct transformations.

Correlation between carpal rotational alignment and postoperative wrist range of motion following total wrist arthroplasty

BackgroundAlthough total wrist arthroplasty (TWA) has become a common treatment option for wrists with damage due to rheumatoid arthritis (RA), the optimal implant axial alignment for TWA has been inadequately studied. This study was performed to investigate the relationships between implant alignment and carpal rotational alignment and the wrist range of motion (ROM) following TWA.MethodsThis study included 18 patients who underwent TWA using a DARTS® Total Wrist System (Teijin Nakashima Medical, Okayama, Japan) for wrist RA. Pre- and 6-month postoperative computed tomography scans were performed, including the radial volar line (Rv), capitohamate axis (CH), and Rv-CH angle in axial scans. The wrist ROM was also measured. The relationship between the Rv-CH angle and ROM was examined.ResultsThe mean Rv-CH angle showed significant wrist pronation from 73.0° to 83.4° postoperatively. We observed a significant positive correlation (0.58) between the postoperative Rv-CH angle and extension and a significant negative correlation (− 0.56) between the postoperative Rv-CH angle and flexion.ConclusionsImplantation of the DARTS® TWA prosthesis resulted in pronation of the carpal axial alignment, which was correlated with postoperative wrist extension. The volar cortex of the distal radius can be a novel reference axis for adequate implant placement.

Analysis of spin directions of galaxies in the DESI Legacy Survey

ABSTRACT The DESI Legacy Survey is a digital sky survey with a large footprint compared to other Earth-based surveys, covering both the Northern and Southern hemispheres. This paper shows the distribution of the spin directions of spiral galaxies imaged by DESI Legacy Survey. A simple analysis of dividing nearly 1.3 × 106 spiral galaxies into two hemispheres shows a higher number of galaxies spinning counterclockwise in the Northern hemisphere, and a higher number of galaxies spinning clockwise in the Southern hemisphere. That distribution is consistent with previous observations, but uses a far larger number of galaxies and a larger footprint. The larger footprint allows a comprehensive analysis without the need to fit the distribution into an a priori model, making this study different from all previous analyses of this kind. Fitting the spin directions of the galaxies to cosine dependence shows a dipole axis alignment with probability of P &amp;lt; 10−5. The analysis is done with a trivial selection of the galaxies, as well as simple explainable annotation algorithm that does not make use of any form of machine learning, deep learning, or pattern recognition. While further work will be required, these results are aligned with previous studies suggesting the possibility of a large-scale alignment of galaxy angular momentum.

Influence of implantation of a total hip endoprosthesis on the ipsilateral leg alignment: the effect of sex and dysplasia of the hip

IntroductionDifferences in leg and hip morphology exist between sexes and developmental hip dysplasia is known to alter proximal femoral morphology. The purpose of this study was to determine whether existing differences in leg alignment due to sex or developmental hip dysplasia have an effect on changes in leg alignment after total hip arthroplasty.Materials and methods30 hip osteoarthritis patients underwent biplanar full-length radiography in the standing position preoperatively and 3 months after total hip arthroplasty. Differences in leg alignment between men and women and between patients with primary hip osteoarthritis and patients with developmental dysplasia before and after surgery were tested using a general linear model for repeated measures.ResultsImplantation of a hip prosthesis had no differential effect on ipsilateral leg alignment in patients with hip osteoarthritis due to dysplasia and in patients with primary hip osteoarthritis. However, patients with hip osteoarthritis due to dysplasia had a 2.1° higher valgus both before and after surgery. After total hip arthroplasty, women had a significantly greater increase in varus angle (1.6° vs. 0°) and femoral offset (10.5 vs. 4.6 mm) compared with men. Because the change in acetabular offset was smaller (2.2 vs. 6.2 mm), the global femoral offset was only increased in women. Femoral torsion was constant for men (15.0° and 16.5°), whereas femoral torsion was significantly reduced in women (19.9° and 13.2°).ConclusionsHip arthroplasty has a greater effect on leg axis in women than in men. The axial leg alignment of women could change from a natural valgus to a varus alignment. Therefore, surgeons should consider the effects of total hip arthroplasty on leg alignment in patients with hip osteoarthritis. Whether these changes in leg alignment are also clinically relevant and lead to premature medial or lateral knee osteoarthritis should be investigated in future work.Trial registrationThis study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018.

Online Instruction to Measure Axial Alignment with the Bonesetter App.

Background and objectives: Alignment of the lower extremity is important when treating congenital deformities, fractures, and joint replacement. During the COVID-19 pandemic, AO North America offered an online course on deformity measurement and planning. The Bonesetter app is a deformity planning tool that is freely available online. The purpose of this study was to see how effective an online course was in teaching axial alignment measurement and to assess that skill using an online digital planning tool, the Bonesetter app. Materials and Methods: An online module on axial alignment was provided during the AONA osteotomy course as well as a tutorial on how to use an online digital planning tool (Bonesetter app). The tools within the Bonesetter app allow users to draw digital lines directly on the CT images and measure the exact angle between two planes. Participants in this study were directed to perform these measurements in four different cases that tested different variations of deformity. Results: The measurements were completed correctly in case 1 = 56%, case 2 = 61%, case 3 = 84%, and case 4 = 76%. The standard deviation of angular digital measurements between individuals was ±4.26 degrees. Measuring the angle directly vs. drawing angles to a horizontal line had smaller standard deviations per case (p < 0.005) and less incidents outside 1 standard deviation for each measurement. Errors in adding and subtracting were the most common errors, particularly in relation to femoral anteversion or retroversion. Conclusions: The online course successfully instructed a group of orthopedic surgeons to measure alignment and malalignment of lower limb axial deformities. The Bonesetter app helped participants to learn this skill and identify errors in measurement. The inability to differentiate between anteversion and retroversion of the femur is a common source of error when it occurs and should be a focus of instruction.