bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation in the patellar tendon moment arm identified with an improved measurement framework
Authors: Dandridge Oliver , Garner Amy , Amis Andrew A. , Cobb Justin P. , van Arkel Richard J. 
Published: July 2021

AbstractThe mechanical advantage of the knee extensor mechanism depends heavily on the patellar tendon moment arm (PTMA). Understanding which factors contribute to its variation may help improve functional outcomes following arthroplasty. This study optimized PTMA measurement, allowing us to quantify the contribution of different variables. The PTMA was calculated about the instantaneous helical axis of tibiofemoral rotation from optical tracked kinematics. A fabricated knee model facilitated calculation optimization, comparing four data smoothing techniques (raw, Butterworth filtering, generalized cross‐validated cubic spline‐interpolation and combined filtering/interpolation). The PTMA was then measured for 24 fresh‐frozen cadaveric knees, under physiologically based loading and extension rates. Combined filtering/interpolation enabled sub‐mm PTMA calculation accuracy throughout the range of motion (root‐mean‐squared error 0.2 mm, max error 0.4 mm), whereas large errors were measured for raw, filtered‐only and interpolated‐only techniques at terminal flexion/extension. Before scaling, the mean PTMA was 46 mm; PTMA magnitude was consistently larger in males (mean differences: 5 to 10 mm, p < .05) and was strongly related to knee size: larger knees have a larger PTMA. However, while scaling eliminated sex differences in PTMA magnitude, the peak PTMA occurred closer to terminal extension in females (female 15°, male 29°, p = .01). Knee size accounted for two‐thirds of the variation in PTMA magnitude, but not the flexion angle where peak PTMA occurred. This substantial variation in angle of peak PTMA has implications for the design of musculoskeletal models and morphotype‐specific arthroplasty. The developed calculation framework is applicable both in vivo and vitro for accurate PTMA measurement.
Interaction of loading and ligament injuries in subtalar joint instability quantified by 3D weightbearing computed tomography
Authors: Burssens Arne , Krähenbühl Nicola , Lenz Amy L. , Howell Kalebb , Zhang Chong , Sripanich Yantarat , Saltzman Charles L. , Barg Alexej 
Published: July 2021

AbstractDespite decades of research since its first description, subtalar joint instability remains a diagnostic enigma within the concept of hindfoot instability. This could be attributed to current imaging techniques, which are impeded by two‐dimensional measurements. Therefore, we used weightbearing computed tomography imaging to quantify three‐dimensional displacement associated with subtalar joint instability. Three‐dimensional models were generated in seven paired cadaver specimens to compute talocalcaneal displacement after different patterns of axial load (85 kg) combined with torque in internal and external rotation (10 Nm). Sequential imaging was repeated in the subtalar joint containing intact ligaments to determine reference displacement. Afterward, the interosseus talocalcaneal ligament (ITCL) or calcaneofibular ligament (CFL) was sectioned, then the ITCL with CFL and after the ITCL, CFL with the deltoid ligament (DL). The highest translation could be detected in the dorsal direction and the highest rotation occurred in the internal direction when external torque was applied to the foot without load. These displacements differed significantly from the condition containing intact ligaments, with a mean difference of 1.6 mm (95% CI, 1.3 to 1.9) for dorsal translation and a mean of 12.4° (95% CI, 10.1 to 14.8) for internal rotation. Clinical relevance: Our study provides a novel and noninvasive analysis to quantify subtalar joint instability based on three‐dimensional WBCT imaging. This approach overcomes former studies using trans‐osseous fixation to determine three‐dimensional subtalar joint displacement and implements an imaging device and software modalities that are readily available. Based on our findings, we recommend applying torque in external rotation to the foot to optimize the detection of subtalar joint instability.
MRI‐based synthetic CT shows equivalence to conventional CT for the morphological assessment of the hip joint
Authors: Florkow Mateusz C. , Willemsen Koen , Zijlstra Frank , Foppen Wouter , van der Wal Bart C. H. , van der Voort van Zyp Jochem R. N. , Viergever Max A. , Castelein René M. , Weinans Harrie , van Stralen Marijn , Sakkers Ralph J. B. , Seevinck Peter R. 
Published: July 2021

AbstractThis study evaluated the accuracy of synthetic computed tomography (sCT), as compared to CT, for the 3D assessment of the hip morphology. Thirty male patients with asymptomatic hips, referred for magnetic resonance (MR) imaging and CT, were included in this retrospective study. sCT images were generated from three‐dimensional radiofrequency‐spoiled T1‐weighted multi‐echo gradient‐echo MR images using a commercially available deep learning‐enabled software and were compared with CT images through mean error and surface distance computation and by means of eight clinical morphometric parameters relevant for hip care. Parameters included center‐edge angle (CEA), sharp angle, acetabular index, extrusion index, femoral head center‐to‐midline distance, acetabular version (AV), and anterior and posterior acetabular sector angles. They were measured by two senior orthopedic surgeons and a radiologist in‐training on CT and sCT images. The reliability and agreement of CT‐ and sCT‐based measurements were assessed using intraclass correlation coefficients (ICCs) for absolute agreement, Bland–Altman plots, and two one‐sided tests for equivalence. The surface distance between CT‐ and sCT‐based bone models were on average submillimeter. CT‐ and sCT‐based measurements showed moderate to excellent interobserver and intraobserver correlation (0.56 < ICC < 0.99). In particular, the inter/intraobserver agreements were good for AV (ICC > 0.75). For CEA, the intraobserver agreement was good (ICC > 0.75) and the interobserver agreement was moderate (ICC > 0.69). Limits of agreements were similar between intraobserver CT and intermodal measurements. All measurements were found statistically equivalent, with average intermodal differences within the intraobserver limits of agreement. In conclusion, sCT and CT were equivalent for the assessment of the hip joint bone morphology.
Optimizing outcomes of ACL surgery—Is autograft reconstruction the only reasonable option?
Authors: Murray Martha M. 
Published: July 2021

AbstractAnterior cruciate ligament (ACL) injuries occur at a high frequency in the United States with approximately 400,000 ACL reconstructions being performed each year. While ACL reconstruction is our current gold standard of treatment, it does not restore joint motion, or prevent the premature development of posttraumatic osteoarthritis (PTOA) in many patients. Thus, new treatments for an ACL injury, which are less invasive and minimize patient morbidity, including cartilage damage, are highly desirable. We have used a tissue‐engineered approach to stimulate ligament healing, to improve upon current treatment options. In this review, we describe and discuss our work moving a tissue engineering strategy from the concept to bench, preclinical, clinical trials and ultimately FDA 510(k) de Novo approval, providing clinicians and patients with a viable alternative to ACL reconstruction.
State of the mineralized tissue comprising the femoral ACL enthesis in young women with an ACL failure
Authors: Patton Daniella M. , Ochocki Danielle N. , Martin Colin T. , Casden Michael , Jepsen Karl J. , Ashton‐Miller James A. , Wojtys Edward M. , Schlecht Stephen H. 
Published: July 2021

AbstractDespite poor graft integration among some patients that undergo an anterior cruciate ligament (ACL) reconstruction, there has been little consideration of the bone quality into which the ACL femoral tunnel is drilled and the graft is placed. Bone mineral density of the knee decreases following ACL injury. However, trabecular and cortical architecture differences between injured and non‐injured femoral ACL entheses have not been reported. We hypothesize that injured femoral ACL entheses will show significantly less cortical and trabecular mass compared with non‐injured controls. Femoral ACL enthesis explants from 54 female patients (13–25 years) were collected during ACL reconstructive surgery. Control explants (n = 12) were collected from seven donors (18−36 years). Injured (I) femoral explants differed from those of non‐injured (NI) controls with significantly less (p ≤ 0.001) cortical volumetric bone mineral density (vBMD) (NI: 736.1–867.6 mg/cm3; I: 451.2–891.9 mg/cm3), relative bone volume (BV/TV) (NI: 0.674–0.867; I: 0.401–0.792) and porosity (Ct.Po) (NI: 0.133–0.326; I: 0.209–0.600). Injured explants showed significantly less trabecular vBMD (p = 0.013) but not trabecular BV/TV (p = 0.314), thickness (p = 0.412), or separation (p = 0.828). We found significantly less cortical bone within injured femoral entheses compared to NI controls. Lower cortical and trabecular bone mass within patient femoral ACL entheses may help explain poor ACL graft osseointegration outcomes in the young and may be a contributor to the osteolytic phenomenon that often occurs within the graft tunnel following ACL reconstruction.
Identifying alternative antibiotics that elute from calcium sulfate beads for treatment of orthopedic infections
Authors: Levack Ashley E. , Turajane Kathleen , Driscoll Daniel A. , Yang Xu , Miller Andy O. , Bostrom Mathias P. , Wellman David S. , Carli Alberto V. 
Published: July 2021

AbstractThere has been increasing interest in the use of a synthetic absorbable calcium sulfate (CaSO4) for local antibiotic delivery in orthopaedic infections. The purpose of this study was to quantify elution kinetics of six antibiotics (amikacin, meropenem, fosfomycin, minocycline, cefazolin, and dalbavancin) from a clinically relevant CaSO4 bead model and compare elution and antimicrobial activity to the current clinical gold standards: vancomycin and tobramycin. Antibiotic‐loaded synthetic CaSO4 beads were immersed in phosphate buffered saline and incubated at 37°C. Eluent was harvested at eight time points over 28 days. Antibiotic concentrations were measured by high performance liquid chromatography to quantify elution rates. CaSO4 beads demonstrated burst release kinetics. Dalbavancin, cefazolin, and minocycline all demonstrated similar elution profiles to vancomycin. Amikacin and meropenem demonstrated favorable elution profiles and durations of above‐minimum inhibitory concentration when compared to tobramycin.Clinical Significance: This study provides important novel data regarding the utility of amikacin, meropenem and dalbavancin as alternative choices to place in CaSO4 carriers when treating orthopaedic infections.
MRI‐­ and CT‐­based metrics for the quantification of arthroscopic bone resections in femoroacetabular impingement syndrome
Authors: Guidetti Martina , Malloy Philip , Alter Thomas D. , Newhouse Alexander C. , Espinoza Orías Alejandro A. , Inoue Nozomu , Nho Shane J. 
Published: July 2021

AbstractThe purpose of this in vitro study was to quantify the bone resected from the proximal femur during hip arthroscopy using metrics generated from magnetic resonance imaging (MRI) and computed tomography (CT) reconstructed three­dimensional (3D) bone models. Seven cadaveric hemi­pelvises underwent both a 1.5 T MRI and CT scan before and following an arthroscopic proximal femoral osteochondroplasty. The images from MRI and CT were segmented to generate 3D proximal femoral surface models. A validated 3D‐­3D registration method was used to compare surface‐­to­‐surface distances between the 3D models before and following surgery. The new metrics of maximum height, mean height, surface area and volume, were computed to quantify bone resected during osteochondroplasty. Stability of the metrics across imaging modalities was established through paired sample t‐­tests and bivariate correlation. Bivariate correlation analyses indicated strong correlations between all metrics (r = 0.728­–0.878) computed from MRI and CT derived models. There were no differences in the MRI‐ and CT‐based metrics used to quantify bone resected during femoral osteochondroplasty. Preoperative­ and postoperative MRI and CT derived 3D bone models can be used to quantify bone resected during femoral osteochondroplasty, without significant differences between the imaging modalities.
Meta‐regression methods to characterize evidence strength using meaningful‐effect percentages conditional on study characteristics
Authors: Mathur Maya B. , VanderWeele Tyler J. 
Published: July 2021

AbstractMeta‐regression analyses usually focus on estimating and testing differences in average effect sizes between individual levels of each meta‐regression covariate in turn. These metrics are useful but have limitations: they consider each covariate individually, rather than in combination, and they characterize only the mean of a potentially heterogeneous distribution of effects. We propose additional metrics that address both limitations. Given a chosen threshold representing a meaningfully strong effect size, these metrics address the questions: “For a given joint level of the covariates, what percentage of the population effects are meaningfully strong?” and “For any two joint levels of the covariates, what is the difference between these percentages of meaningfully strong effects?” We provide semiparametric methods for estimation and inference and assess their performance in a simulation study. We apply the proposed methods to meta‐regression analyses on memory consolidation and on dietary behavior interventions, illustrating how the methods can provide more information than standard reporting alone. To facilitate implementing the methods in practice, we provide reporting guidelines and simple R code.
The finite subsets and the permutations with finitely many non‐fixed points of a set
Authors: Nuntasri Jukkrid , Panasawatwong Supakun , Vejjajiva Pimpen 
Published: July 2021

AbstractWe write and for the cardinalities of the set of finite subsets and the set of permutations with finitely many non‐fixed points, respectively, of a set which is of cardinality . In this paper, we investigate relationships between and for an infinite cardinal in the absence of the Axiom of Choice. We give conditions that make and comparable as well as give related consistency results.
Impulse Control Disorders in Parkinson's Disease: Has COVID‐19 Related Lockdown Been a Trigger?
Authors: Rábano‐Suárez Pablo , Martínez‐Fernández Raúl , Natera‐Villalba Elena , Pareés Isabel , Martínez‐Castrillo Juan Carlos , Alonso‐Canovas Araceli 
Published: July 2021

ABSTRACTBackgroundParkinson's disease (PD) patients, especially those on dopamine agonists (DA), are at risk of impulse control disorders (ICD). Little attention has been paid to the influence of environmental factors.CasesRetrospective analysis of consecutive PD patients seen in our outpatient Movement Disorders Clinic during 2 months (September–November 2020) to explore the frequency of ICD during the preceding 2‐month lockdown period, and comparison with an equivalent control group (September–November 2019). Among 114 patients assessed, 15 (13%) presented ICD during the lockdown, versus 6 (4.5%, P 0.02) in the control group. When analyzing only patients on DA, ICD occurrence increased to 31% (vs. 9.6% pre‐lockdown, P 0.026). ICD during lockdown required drug regime adjustment in 80% (vs. 16.7% pre‐lockdown, P 0.014).ConclusionDuring COVID‐19 lockdown, the occurrence of ICD in PD patients taking DA was higher than expected, and with increased severity. Environmental stressors may play a role in ICD presentation in vulnerable patients.
Spot on: C‐H‐Aktivierung
Authors: van Gemmeren Manuel 
Published: July 2021

AbstractKohlenstoff‐Wasserstoff‐Bindungen mit Übergangsmetallen zu aktivieren ermöglicht, funktionelle Gruppen und Substituenten in ansonsten inerten Positionen eines Moleküls einzuführen. Dies eignet sich zur Naturstoffsynthese und zur Funktionalisierung in späten Synthesestadien. Dozentenpreisträger Manuel van Gemmeren entwickelt solche Methoden.
Hauptgruppenelementbasierte Lewis‐Supersäuren
Authors: Hanf Schirin 
Published: July 2021

AbstractLange haben Bor‐ und Aluminiumverbindungen die Chemie der Lewis‐Supersäuren dominiert. Inzwischen bearbeiten Forschungsgruppen auch Lewis‐Supersäuren aus den Elementen der Gruppen 13 bis 15. Eine Übersicht über deren Reaktivität und Anwendungsgebiete.
Vertical alignment of carbon fibers under magnetic field driving to enhance the thermal conductivity of silicone composites
Authors: Ma Haoqi , Gao Bin , Wang Meiyu , Feng Yakai 
Published: July 2021

AbstractThermal interface materials are expected to have efficient heat conduction pathways to achieve excellent thermal conductivity under the premise of low filler filling. It is a facile strategy to build thermal pathways through filler orientation technology under external force. Herein, iron oxide nanoparticles (Fe3O4) were immobilized onto the surface of carbon fiber (CF) to prepare magnetic CF by polydopamine technology, and the oriented CF/polydimethylsiloxane composites (OCF/PDMS) were prepared through the vertically oriented cure of magnetized CF under an external magnetic field. Importantly, the thermal conductivity of OCF/PDMS reached up to 1.51 W m−1 K−1 when filling 20 wt% of CF@Fe3O4, which is 1.16 times of carbon fiber/polydimethylsiloxane composites and 5.59 times of pure PDMS matrix. In addition, OCF/PDMS also exhibits excellent tensile strength, elastic modulus and elongation at break. This strategy provides a promising attempt for the construction of thermal interface materials with high thermal conductivity and excellent mechanical properties.
CyDisCo production of functional recombinant SARS‐CoV‐2 spike receptor binding domain
Authors: Prahlad Janani , Struble Lucas R. , Lutz William E. , Wallin Savanna A. , Khurana Surender , Schnaubelt Andy , Broadhurst Mara J. , Bayles Kenneth W. , Borgstahl Gloria E. O. 
Published: July 2021

AbstractThe COVID‐19 pandemic caused by SARS‐CoV‐2 has applied significant pressure on overtaxed healthcare around the world, underscoring the urgent need for rapid diagnosis and treatment. We have developed a bacterial strategy for the expression and purification of a SARS‐CoV‐2 spike protein receptor binding domain (RBD) that includes the SD1 domain. Bacterial cytoplasm is a reductive environment, which is problematic when the recombinant protein of interest requires complicated folding and/or processing. The use of the CyDisCo system (cytoplasmic disulfide bond formation in E. coli) bypasses this issue by pre‐expressing a sulfhydryl oxidase and a disulfide isomerase, allowing the recombinant protein to be correctly folded with disulfide bonds for protein integrity and functionality. We show that it is possible to quickly and inexpensively produce an active RBD in bacteria that is capable of recognizing and binding to the ACE2 (angiotensin‐converting enzyme) receptor as well as antibodies in COVID‐19 patient sera.
Opening a new era of investigating unreachable cliff flora using smart UAVs
Authors: Zhou Hui , Zhu Jiaxing , Li Jiaxiang , Xu Yongfu , Li Qian , Yan Enping , Zhao Shaohua , Xiong Yujiu , Mo Dengkui 
Published: July 2021

AbstractCliff ecosystems are considered the ‘Last Unknown’ because cliffs may host ancient and unique species that are located in extremely hostile environments and are difficult to reach. However, comprehensive and systematic information and databases of cliff flora are unavailable; and obtaining information on these undisturbed ecosystems and cliff flora is fundamental and is of high priority for botanists. We present the first systematically sampled expert‐verified checklist of cliff flora from the ground to the top of cliffs in these harsh environments based on high‐resolution visible imagery captured with close‐range photogrammetry by a smart remote‐controlled unmanned aerial system (UAS). Using approximately 9200 records retrieved from high‐resolution images of 197 cliffs in the Wulingyuan global cultural heritage area, a mid‐subtropical region in China, we identified 267 vascular plant species, 140 genera and 58 families, excluding herbaceous plants. The maximum diversity was attributable to a few dominant families and genera, and most of the genera and families were represented by only a few species. Our findings highlight the unique floristic patterns as well as morphology on these cliffs that warrant further study and the potential for the use of a smart UAS to investigate cliff flora at large and global scales.
Using camera traps to estimate ungulate abundance: a comparison of mark–resight methods
Authors: Taylor Jace C. , Bates Steven B. , Whiting Jericho C. , McMillan Brock R. , Larsen Randy T. 
Published: July 2021

AbstractMany global wildlife populations are experiencing unprecedented declines. Estimates of population abundance are needed to effectively manage common species and to conserve vulnerable species. Camera traps have advanced as wildlife monitoring tools for ungulates and can provide improved methods of estimating population abundance. Little is known, however, about how camera traps set for ungulates compare with traditional methods (e.g., ground and aerial surveys) used simultaneously. From 2012 to 2014, we captured and radio collared 34 female and 32 male bighorn sheep (Ovis canadensis) in a closed population in Utah, USA. Each collar had a unique letter and number combination. We then estimated number of young, females and yearlings, males and population abundance using multiple methods simultaneously: helicopter surveys, resight surveys performed from the ground, camera trap surveys using marked but not individually identifiable individuals and camera trap surveys using marked and individually identifiable animals. All methods estimated similar abundance. Across years, ages and sexes, however, camera trap surveys produced the most consistent and precise estimates of abundance for adult females and yearlings, lambs and the population. That method was less intrusive and safer than helicopter surveys. Our results indicate that camera trap surveys using photographs of marked animals in which the majority of the population visits a specific resource can produce precise estimates of abundance that are safer, as well as less intrusive and expensive than traditional methods. Using camera traps also creates a permanent record of photographs that can be archived and reanalyzed to answer future ecological and population questions. Finally, this method of estimating abundance can be used in other areas with ungulates that congregate around resources (e.g., watering sites or mineral licks).