Shortening Rate Research Articles

Elevated tissue status of omega-3 fatty acids protects against age-related telomere attrition in fat-1 transgenic mice

Leukocyte telomere length (LTL) is a biomarker of aging that may be influenced by dietary factors. Omega-3 fatty acids (n-3 FA) have been suggested to affect LTL. However, research on this effect has been inconclusive. The aim of the study was to test the hypothesis about the positive effect of n-3 FA on LTL. Fat-1 transgenic mice, which can convert omega-6 fatty acids (n-6 FA) to n-3 FA and have elevated levels of endogenous n-3 FA in their tissues, were used to study the effects of n-3 FA on LTL at different ages. Blood samples from 10-month-old wild-type (WT) mice (n=10) and fat-1 mice (n=10) and 3-month-old WT mice (n=5) and fat-1 mice (n=5) were used to measure relative and absolute LTL. The levels of proteins critical for telomere maintenance were examined by Western blot analysis. Fat-1 transgenic mice had longer leukocyte telomeres than their WT siblings, suggesting a slower rate of age-related telomere shortening in fat-1 mice. In animals aged 10 months, the LTL was significantly longer in fat-1 than in WT mice (mean±SEM; relative LTL: WT=1.00±0.09 vs. fat-1: 1.25±0.05, P=0.031; absolute LTL: WT=64.41±6.50 vs. fat-1: 78.53±3.86, P=0.048). The difference in LTL observed in three-month-old mice was insignificant, however the mean LTL was still longer in fat-1 mice than in the WT mice. Fat-1 mice also had abundant levels of two shelterin proteins: TRF1 (27%, P=0.028) and TRF2 (47%, P=0.040) (telomeric repeat binding factor 1 and 2) compared to WT animals. This study, for the first time in a unique animal model free of dietary confounders, has demonstrated that increased levels of n-3 FA in tissues can reduce telomere attrition. The data presented indicate the possibility of using omega-3 fatty acids to reduce accelerated telomere attrition and, consequently, counteract premature aging and reduce the risk of age-related diseases.

Aging Reduces Cardiac Contractility by Altering Cardiac Regulatory and Contractile Proteins

Aging is associated with an increased incidence of cardiac dysfunction. We hypothesized that aging associated changes in cardiac regulatory and contractile proteins produce contractile dysfunction. We assessed regulatory and contractile protein expression as well as contractility in left ventricular cardiac muscle from Fischer F-344 rats at 6-, 18-, and 24-month of age. Age-related changes in the expression of β-MHC as well as the expression and phosphorylation of troponin I (TnI) and cardiac myosin binding C protein (MyBP-C) were assessed by Western blot. Aging was associated with an increase in the expression of β-MHC and the phosphorylation of both TnI at Ser23/24 and MyBP-C. Mechanical properties were assessed in Triton-X permeabilized anterior papillary muscle from the left ventricle from both 6- and 24-month old rats. In papillary muscle of 24-month old rats, there was a decrease in maximum Ca2+ activated force, Ca2+ sensitivity of force and the rate constant for force recovery after quick release (ktr). Additionally, cardiomyocytes were isolated from the left ventricle at 6-, 18-, and 24-month of age using a modified Langendorff system. Cardiomyocytes were then loaded with fura-2 AM to measure cytosolic calcium ([Ca2+]cyt) responses to electrical field stimulation (0.5 Hz). [Ca2+]cyt and contractile (sarcomere length shortening) responses to stimulation were simultaneously measured using an IonOptix system. In older cardiomyocytes, the amplitude of evoked [Ca2+]cyt responses was reduced while there was no difference in the kinetics of the [Ca2+]cyt transient. The extent of sarcomere length shortening as well as the rates of both shortening and relaxation were reduced. These results demonstrate that aging is associated with changes in the expression and phosphorylation of contractile and regulatory proteins, which produce changes in cardiac contractility. Supported by a Mayo CV Prospective Grant (FVB). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The present-day kinematics of the Tianshan orogenic belt constrained by GPS velocities

Since the late Cenozoic, the reactivated Tianshan orogenic belt has accommodated crustal shortening exceeding 200 km, primarily due to the far-field effects of the India-Eurasia plate collision. However, the details of the strain partitioning in the Tianshan Mountain range remain elusive. We interpret a new compilation of GPS velocities covering the whole Tianshan range with a classic elastic block model. Compared to previous studies with a block modeling approach, the Tianshan orogenic belt is further subdivided into several blocks based on geological fault traces and a clustering analysis approach. In addition to obvious crustal shortening on the bounding thrust faults of the Tianshan, our inverted fault slip rates also reveal that faults within the Tianshan orogenic belt, such as the Nalati Fault and the southern margin of the Issyk-Kul Lake Fault, which plays a crucial role in accommodating the tectonic crustal shortening. In the 72°E−78°E region, the internal shortening rate within the mountain is approximately 5–7 mm/yr. Besides crustal shortening, strike-slip motion occurs on faults in the interior of the mountain range as well as in the foreland fold-and-thrust belts, especially in the southern margin of the Tianshan. These findings suggest that the crustal deformation in the Tianshan Mountain range is more complex than previously thought, and the oblique convergence between the Tarim Basin and the Tianshan probably results in both strike-slip and thrust motion.

Reconstructing the Evolution of Foreland Fold‐And‐Thrust Belts Using U‐Pb Calcite Dating: An Integrated Case‐Study From the Easternmost Jura Mountains (Switzerland)

AbstractThis case‐study from the Jura Mountains in the foreland of the European Alps demonstrates how the coupling of subsurface analysis and U‐Pb carbonate dating can provide absolute timing constraints and shortening rate estimates of fold‐and‐thrust belts. It is confirmed that the initial Late Cenozoic foreland deformation driving the formation of the easternmost Jura Mountains in Switzerland was predominately thin‐skinned with contractional deformation largely restricted to the Mesozoic succession above a sub‐horizontal basal décollement. Thereby, the localization and structural style of related deformation structures was strongly guided by the characteristics of underlying Late Paleozoic half grabens. The main thin‐skinned thrust front formed at ∼12 Ma, followed by further deformation in the hinterland and locally continued foreland‐directed thrust propagation. The major deformation zones exposed at surface were established at ∼8 Ma but shortening continued until at least ∼4 Ma. Thick‐skinned contraction associated with the inversion of basement structures only played a subordinate role during the latest deformation phase after 8 Ma. Based on cumulative shortening values derived from balanced cross sections, our U‐Pb ages of syn‐tectonic calcite slickenfibres allow to estimate thin‐skinned deformation rates for the easternmost Jura Mountains between ∼0.9 and ∼0.1 mm/year, decreasing toward the eastern tip of the arcuate belt. Moreover, deformation rates seemingly decreased over time with rates of initial thin‐skinned thrusting being significantly higher than the later deformation north of the main thrust front. These new findings from a classical foreland setting highlight the potential of integrating U‐Pb dating in regional fold‐and‐thrust belt investigations elsewhere.

Teneligliptin mitigates diabetic cardiomyopathy by inhibiting activation of the NLRP3 inflammasome

BACKGROUND Diabetic cardiomyopathy (DCM), which is a complication of diabetes, poses a great threat to public health. Recent studies have confirmed the role of NLRP3 (NOD-like receptor protein 3) activation in DCM development through the inflammatory response. Teneligliptin is an oral hypoglycemic dipeptidyl peptidase-IV inhibitor used to treat diabetes. Teneligliptin has recently been reported to have anti-inflammatory and protective effects on myocardial cells. AIM To examine the therapeutic effects of teneligliptin on DCM in diabetic mice. METHODS Streptozotocin was administered to induce diabetes in mice, followed by treatment with 30 mg/kg teneligliptin. RESULTS Marked increases in cardiomyocyte area and cardiac hypertrophy indicator heart weight/tibia length reductions in fractional shortening, ejection fraction, and heart rate; increases in creatine kinase-MB (CK-MB), aspartate transaminase (AST), and lactate dehydrogenase (LDH) levels; and upregulated NADPH oxidase 4 were observed in diabetic mice, all of which were significantly reversed by teneligliptin. Moreover, NLRP3 inflammasome activation and increased release of interleukin-1β in diabetic mice were inhibited by teneligliptin. Primary mouse cardiomyocytes were treated with high glucose (30 mmol/L) with or without teneligliptin (2.5 or 5 µM) for 24 h. NLRP3 inflammasome activation. Increases in CK-MB, AST, and LDH levels in glucose-stimulated cardiomyocytes were markedly inhibited by teneligliptin, and AMP (p-adenosine 5‘-monophosphate)-p-AMPK (activated protein kinase) levels were increased. Furthermore, the beneficial effects of teneligliptin on hyperglycaemia-induced cardiomyocytes were abolished by the AMPK signaling inhibitor compound C. CONCLUSION Overall, teneligliptin mitigated DCM by mitigating activation of the NLRP3 inflammasome.

Disagreements in Geodetically Inferred Strain Rates in the Western US With Stress Orientations and Geologic Moment Rates

AbstractI employ an elasticity‐based method to invert a geodetically derived surface velocity field in the western US using for present‐day surface strain rate fields with uncertainties. The method uses distributed body forces in a thin elastic sheet and allows for discontinuities in velocity across creeping faults using the solution for dislocations in a thin elastic plate. I compare the strain rate fields with previously published stress orientations and moment rates from geological slip rate data and previous geodetic studies. Geologic and geodetic moment rates are calculated using slip rate and off‐fault strain rates from the 2023 US National Seismic Hazard Model (NSHM) deformation models. I find that computed total geodetic moment rates are higher than NSHM summed moment rates on faults for all regions of the western US except the highest deforming rate regions including the Western Transverse Ranges and the northern and southern San Andreas Fault (SAF) system in California. Computed geodetic moment rates are comparable to the moment rates derived from the geodetically based NSHM deformation models in all regions. I find systematic differences in orientations of maximum horizontal shortening rate and maximum horizontal compressive stress in the Pacific Northwest region and along much of the SAF system. In the Pacific Northwest, the maximum horizontal stress orientations are rotated counterclockwise 40–90° relative to the maximum horizontal strain rate directions. Along the SAF system, the maximum horizontal stresses are rotated systematically 25–40° clockwise (closer to fault normal) relative to the strain rates.

Kinematic modeling of neotectonic thrusts at the Andean orogenic front (southern Precordillera, Argentina)

The south-central Andes located between 32°-33° S are considered to be a transitional zone between the flat-lying and the normal subduction zones of the Nazca Plate. The active mountain-building processes are mainly concentrated between the Andean eastern foothills and the adjacent broken foreland, as highlighted by crustal seismicity, historic destructive earthquakes, and Quaternary-active contractional structures. Between 32° 10′ and 32° 40′ S, the Andean orogenic front is exposed at the Las Peñas-Las Higueras range, where east- and west-verging thrusts interact, resulting in an antithetic linkage transfer zone. We built kinematically-balanced structural sections through the integration of surface and subsurface data (2D seismic lines) to achieve a 3D characterization of the Quaternary-active thrusts and to estimate shortening rates of ∼1.8–3.4 mm/a during the last ∼8.5 Ma, thus extending the spatial and temporal penetration achieved by surface geology data. Our results indicate that the main east-verging thrusts detach at a depth of ∼10 km within Paleozoic basement rocks. This outcome implies larger potential rupture areas than if rooted at Neogene layers. West-verging thrusts present detachment levels at ∼5 km, also linked to Paleozoic basement rocks. The analysis of 2D seismic lines has also contributed to the recognition of blind thrusts without a morphologic signature, which could be regarded as relevant seismogenic structures.

Kinematic reconstruction of active tectonic and halokinetic structures in the 2021 NW Palagruža earthquake area (Central Adriatic)

In March 2021, a compressional earthquake sequence (mainshock Mw 5.2) occurred in the Central Adriatic Sea, offshore Croatia. The struck area is characterized by a complex tectonic settings due to due interaction between tectonic and halokinetic structures. Former studies in this region, mostly based on geophysical and seismological data, do not provide a comprehensive description of the geological complexities of the area, caused by the presence of different types of active structures. Following the interpretation and depth conversion of a set of seismic reflection profiles, we present a kinematic restoration to obtain the shortening rates for the last 6 Myr. We highlight the presence of three main types of active structures: i) shallow thrusts and related folds deforming the seafloor, ii) deep thrusts promoting large-scale deformation, iii) halokinetic structures deforming, at least, the Messinian. We highlight how the structural setting of the area is more complex than previously interpreted, with a possible decoupling of shallow and deep structures and an interaction between tectonic and halokinetic structures. This work opens new perspectives about the role of halokinetic processes in active seismogenic areas.

Dimethyl phthalate induced cardiovascular developmental toxicity in zebrafish embryos by regulating MAPK and calcium signaling pathways

Dimethyl phthalate (DMP), the lowest-molecular-weight phthalate ester (PAE), is one of the most commonly detected persistent organic pollutants in the environment, but its toxic effects, especially cardiovascular developmental toxicity, are largely unknown. In this study, zebrafish embryos were exposed to sublethal concentrations of DMP from 4 to 96 hpf. Our results showed that DMP treatment induced yolk retention, pericardial edema, and swim bladder deficiency, as well as increased SV-BA distance and decreased heart rate, stroke volume, ventricular axis shortening rate and ejection fraction. In addition, oxidative stress and apoptosis were found to be highly involved in this process. The results of transcriptome sequencing and mRNA expression of related genes indicated that MAPK and calcium signaling pathways were perturbed by DMP. These findings have the potential to provide new insights into the potential developmental toxicity and cardiovascular disease risk of DMP.

Pleistocene deformation of the Malargüe fold–thrust belt from structural modelling and geochronology of syntectonic sedimentation

We report uplift and shortening rates from a late Neogene–Pleistocene deformation stage of the frontal fold–thrust belt and adjacent wedge-top in the Principal Cordillera of the southern Central Andes (latitude 33–39°S). A structural model is presented based on integration of surface field data and subsurface 2D seismic sections. Shortening, uplift and sedimentation rates were calculated from different steps of kinematic modelling. Our structural interpretations and modelling are integrated with new detrital zircon U–Pb geochronology to define a previously overlooked Pleistocene period of orogenic shortening and syntectonic sedimentation in the Malargüe basin. This task was possible as a result of the dating of three samples yielding ages between ∼12 and 1 Ma obtained from a 900 m deep well located in the foreland. From stratigraphic correlations, our data record an active Plio-Pleistocene wedge-top depozone coeval with retreat of the volcanism, and the emplacement of retroarc basalts. Structural modelling, together with detrital zircon U–Pb provenance data, registers shortening producing a foredeep to wedge-top Plio-Pleistocene transition, adjusting and completing the knowledge of the frontal fold–thrust belt and foreland basin in the southern Central Andes. Supplementary material: Supplementary tables are available at https://doi.org/10.6084/m9.figshare.c.7033425

Combining geomorphological and kinematic models to analyze tectonic deformation rates: A case study of the Bayin anticline in the eastern Tian Shan Mountains

Quantitatively characterizing the geometry, kinematics, and deformation rate of fold-thrust belts in intermontane basins is the key to understanding strain partitioning within the Tian Shan range. This work focuses on the Bayin anticline in the Youludusi Basin, a typical intermontane basin located within the eastern Tian Shan. The Kaidu River cuts through the Bayin anticline and has developed three levels of terraces (T1–T3) across the structure. By using cosmogenic nuclide and optically stimulated luminescence dating methods, the formation ages of terraces T1 and T3 are constrained to 11.54 ± 0.55 ka and 42 + 7.0/−7.1 ka, respectively. When applying a listric thrust fault model to the Bayin anticline and using terraces as references, the vertical displacements are estimated to be 16.45 + 6.46/−3.19 m (T1), 32.08 + 12.85/−6.19 m (T2), and 95.93 + 38.94/−18.6 m (T3), and the shortening amounts are 10.56 + 8.33/−5.04 m (T1), 20.46 + 16.68/−9.64 m (T2), and 61.24 + 50.22/−28.93 m (T3). Based on this listric thrust fault model and terrace T1–T3 ages, the rate of fault slip controlling the growth of the Bayin anticline is determined to be 1.6 ± 1.0 mm/yr, and the crustal shortening rate of the anticline is 1.0 + 0.7/−0.6 mm/yr. The estimated crustal shortening deformation of the Bayin anticline accounts for ∼12 % of the total deformation in the Youludusi Basin. In terms of the entire orogenic belt, the crustal shortening absorbed in the southern, central, and northern parts accounts for 24 %–56 %, 46 %–71 %, and 19 %–74 %, respectively, of the total strain across the eastern Tian Shan. Therefore, we believe that the Eastern Tianshan undergoes uniform deformation.

Seismogenic depth and seismic coupling estimation in the transition zone between Alps, Dinarides and Pannonian Basin for the new Slovenian seismic hazard model

Abstract. Seismogenic depth and seismic coupling are important inputs into seismic hazard estimates. Although the importance of seismic coupling is often overlooked, it significantly impacts seismic hazard results. We present an estimation of upper and lower seismogenic depth and expected hypocentral depth and seismic coupling in the transition zone between the Alps, Dinarides and Pannonian Basin, characterized by a complex deformation pattern, highly variable crustal thickness, and moderate seismic hazard, supporting the development of the 2021 seismic hazard model of Slovenia. The hazard model was based on three seismic source models: area source model, fault source model and smoothed seismicity (point) source model. We estimated the lower seismogenic depth using seismological and geological data and compared them. The seismological estimate was based on two regional earthquake catalogues prepared for this study. In the area source model, estimates of lower seismogenic depth from seismological data are deeper or equal to the ones derived from geological data, except in one case. In the fault source model, we analysed each fault individually and chose seismological lower depth estimates in 12 among 89 faults as more representative. The seismogenic thickness for each individual fault source was determined for seismic coupling determination. The seismic coupling was assessed by two approaches, i.e. we chose the most trusted value from the literature, and the value determined for each fault individually by using the approach based on the updated regional fault and earthquake data sets. The final estimate of seismic coupling ranges from 0.77 to 0.38. We compared the tectonic moment rate based on long-term slip rate using different values of seismic coupling with the seismic moment rate obtained from the earthquake catalogue. The analysis is done for the whole area, as well as for the individual area zones. The analysis of N–S components of estimated slip for the largest faults in the area of west Slovenia shows that the regional geological and geodetic shortening rates are comparable. The total activity rate of three global seismic source models is compared, which gives up to a 10 % difference. Our results contribute to a better understanding of the seismic activity in the region. The presented approach for seismic coupling estimation can be applied in cases where the total slip rate is given instead of its seismic part and can be used at regional or national level. The approach is also suitable for the cross-border harmonization of the European seismic hazard modelling data.

A comparative study on the deformation behavior and mechanical properties of new lower extremity arterial stents

Background and ObjectiveThe lower extremity movement involves a complex and large amplitude extremity movement process, and arterial stents implanted in the lower extremity are prone to complex mechanical deformation behavior. Hence, the lower extremity arterial stent is required to have favorable comprehensive mechanical properties. MethodsIn this study, a new lower extremity arterial stent (New) was proposed, and its deformation behavior and mechanical properties were analyzed by numerical simulations under different deformation modes, such as radial compression, axial compression/tension, bending, and torsion. Stents with different diameters were modeled to compare the effect of diameter size on their biomechanical properties. Additionally, a comparative analysis was conducted between this new stent and seven commercially available stents. ResultsThe results demonstrated that the stent diameter exerted a significant effect on its deformation behavior and mechanical properties. Specifically, with the increase of the stent diameter, the radial expansion rate, radial shrinkage rate, radial support stiffness, axial compression stiffness, and axial tensile stiffness tended to decrease, and the expansion inhomogeneity, stenosis rate, bending stiffness, and torsional stiffness tended to increase. In contrast, the stent diameter exerted a small effect on the stent axial shortening rate and ellipticity. The new lower extremity arterial stent was validated to outperform other stents in terms of most performance indicators. Especially, the radial expansion rate and ellipticity of the New stent were better than those of all commercially available stents. Moreover, the New stent presented favorable mechanical properties and flexibility under the premise of ensuring the support performance. ConclusionsBased on these findings, this lower extremity arterial stent may play a better therapeutic effect in clinical application. Furthermore, these analysis results may provide reference for the clinical application and selection of the stent.

A Multi-strategy Enhanced Arithmetic Optimization Algorithm and Its Application in Path Planning of Mobile Robots

A multi-strategy enhanced arithmetic optimization algorithm called MSEAOA is proposed to address the issues of low population diversity, imbalanced exploration and exploitation capabilities, and low accuracy of optimal solution in the Arithmetic Optimization Algorithm. Firstly, using the good point set strategy for population initialization to improve population diversity and thus accelerate convergence speed. Secondly, we integrate the exploration and exploition capabilities of differential self-learning strategy, best example learning strategy, and second-order differential perturbation strategy balancing algorithm. Finally, the introduction of somersault foraging strategy improves the accuracy of the optimal solution. We select 14 classical benchmark test functions and the CEC2019 function test set to test the optimization ability of MSEAOA, and apply MSEAOA to the path planning problem of mobile robots. MSEAOA is compared with other meta-heuristic optimization algorithms, and the experimental results are statistically analyzed by the Wilcoxon rank-sum test. The simulation experimental results show that MSEAOA performs the best among 14 benchmark functions, but for 10 CEC2019 functions, MSEAOA has the best optimization performance among 5 of them (50%). In the path optimization problem of mobile robots, the path obtained by MSEAOA is also the best among all algorithms, its path shortening rate exceeds 8.8% in 83% of environments. The results indicate that MSEAOA is a reliable algorithm suitable for function optimization and practical optimization problems.

Structural Interactions Between Deep Mesozoic Strike‐Slip Faults and Shallow Cenozoic Contractional Folds in the Northern Tianshan Foreland Basin (NW China)

AbstractIn the rejuvenated mountain front, preexisting basement structures are often reactivated and interact with the subsequent thin‐skinned deformation. How the deep structures affect the shallower ones is key to establishing the processes and mechanisms for the foreland fold‐and‐thrust system. We presented an exceptional case study on the structural inheritance between the deep Mesozoic strike‐slip faults and the shallow Cenozoic contractional folds from the Northern Tianshan foreland basin, Northwest China, using high‐resolution 2‐D and 3‐D seismic data. Based on the interpretation of seismic data and progressive restoration, our study illustrated the NW‐trending Ai‐Ka strike‐slip faults controlled a dextral shear zone, which initiated the Gaoquan restraining bend in the basement during Jurassic. Later, these strike‐slip structures, close to the mountain front, were reactivated during the N‐S Mio‐Pliocene contraction, and folded the upper décollements that characterized the localization of thin‐skinned deformation. In contrast, in the further foreland, nonreactive strike‐slip faults controlled basal décollement pinch‐out, which localizes the thin‐skinned deformation, resulting in en échelon folds that trace the strike of the deep strike‐slip faults. The onset time of each anticline shows that the thin‐skinned deformation first extended laterally and then propagated further north, resulting in ca. 7 km shortening along the whole foreland. Moreover, the shortening rate decreased eastward from 0.90 to 1.46 mm/yr along the Gaoquan‐Kayindike structural line to 0.24–0.37 mm/yr along the Dunan structural line as the Sikeshu depression, constrained by the NW‐trending Ai‐Ka strike‐slip fault, narrowed eastward. This feature implies that the width of the depression may control the amount of displacement propagation.

Femoral neck system versus dynamic hip screw for fixation of femoral neck fracture in the adult: a meta-analysis.

To determine the efficacy of femoral neck system compared to dynamic hip screws in treating femoral neck fractures. The systematic review was conducted from January to March 2023, and comprised literature search on PubMed, Embase, Scopus, Ovid, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure and Wanfang databases for relevant studies published up to March 1, 2023. Study data as well as demographic and outcome parameters related to the patients were extracted, and the methodological index for non-randomised studies was used to assess the risk of bias. Review Manager software was used to conduct metaanalysis. Of the 567 studies initially found, 6(1%) were included, with the publication date ranging from August 2021 to February 2023. There were 5(83.3%) studies published in English and 1(16.7%) in Chinese. Of the 577 patients with femoral neck fractures, 287(49.7%) were treated with femoral neck system and 290(50.3%) with dynamic hip screws. Significant differences were shown between the two groups regarding operation duration, blood loss, internal fixation failure rate and Harris hip score (p=<0.05). There was no significant differences between the groups regarding time from injury to surgery, hospitalisation, complication rate and femoral neck shortening rate (p>0.05). The novel femoral neck system could optimise surgical procedures, with shorter operation times and lesser blood loss. The femoral neck system and dynamic hip screws were comparable in terms of complication rates and postoperative hip function.

Treatment of Severely Shortened or Comminuted Clavicular Fractures in Older Adolescent Athletes

Background: Recent evidence suggests that for completely displaced midshaft clavicular fractures, surgery offers no clear benefit over nonoperative treatment in a general adolescent population from 10 to 18 years of age. However, the comparative outcomes of comminuted and/or severely shortened clavicular fractures specifically in older adolescent athletes have not been explored in a focused, methodologically rigorous fashion. Hypothesis: The study hypothesis was that outcomes would be superior in older adolescent athletes who underwent operative treatment compared with nonoperative treatment for comminuted and/or severely shortened clavicular fractures. Study Design: Cohort study; Level of evidence, 2. Methods: A level 2, multicenter, prospective cohort study investigating the outcomes of midshaft fractures in adolescents between 2013 and 2017 was filtered to analyze the subcohorts of athletes 14 to 18 years of age with either fracture comminution or fracture shortening of ≥25 mm or both. Patient characteristics, injury mechanisms, fracture characteristics, and treatments were compared. Complications, rates, timing of return to sports (RTS), and patient-reported outcomes (PROs) were analyzed. Results: The 2 treatment groups, which included 136 older adolescent athletes (69 nonoperative, 67 operative), showed similar distributions of primary sport type, competition level, comminution, shortening, and 2-year PRO response rate (n = 99; 73%). The operative group demonstrated 3 mm–greater mean superior displacement, which was therefore statistically controlled for as a confounder in the comparative PRO analysis. No 2-year differences in nonunion, delayed union, symptomatic malunion, refracture, clinically significant complications, or rates of RTS were detected between treatment groups. The difference in timing of RTS (operative, 10.3 weeks; nonoperative, 13.5 weeks) was statistically significant. After controlling for the minor difference in superior displacement, regression analysis and matched comparison cohorts demonstrated no differences between the nonoperative and operative groups in mean or dichotomized PRO scores. Conclusion: In this prospective, multicenter cohort study investigating older adolescent athletes with comminuted and/or severely shortened clavicular fractures, contrary to the study hypothesis, there were no differences in complications, RTS, or PROs between nonoperatively and operatively treated patients at 2 years. Comparably excellent outcomes of severe clavicular fractures in adolescent athletes can be achieved with nonoperative treatment.

The shape of the Himalayan “Arc”: An ellipse pinned by syntaxial strike-slip fault tips

Trans-Himalayan geodetic data show that, between both syntaxes, India/Asia convergence is steadily oriented ≈ N20°E. However, surface faulting near both syntaxes, along the 2005 and 1950 earthquake ruptures, imply long-term thrusting directed ≈ 130° apart, and post-LGM (last Glacial Maximum) shortening rates of ≈ 5 to 6 mm/y, ≈ 2 to 3 times slower than in Nepal (≈ 15 to 20 mm/y). Syntaxial earthquakes' return-time are also ≈ 3 times longer (>2,000 y) than in Nepal (≈ 700 y). In a structural frame centered halfway between the syntaxial cusps, the tectonic features of the range show remarkable symmetry. In map view, the overall shapes of the Main Front Thrust (MFT) and the Main Central Thrust (MCT) closely fit ellipses, with major-to-minor axis ratios of ≈ 2.5 to 3. This suggests that the range growth atop subducting India is "pinned" by the strike-slip faults that bound it to the east and west. Discrete Element Modeling corroborates a late-Tertiary elliptical range growth. This accounts for the ≈ 65° angles and twofold to threefold decrease in active thrusting between Nepal and the syntaxes, for the maximum Himalayan heights (≥8,000 m), larger magnitudes (≥8), and shorter return-time (≈ 700 y) of great earthquakes in Nepal, for the existence of two 500- to 600 km-long, south-concave mountain ranges north of both syntaxes and for the ≈ 9 mm/y, N100 to 110°E extension across southern Tibet. It also suggests that predictions of impending or frequent great earthquakes in the eastern- and westernmost Himalayas may be overstated.

Morphological and functional changes of the geniohyoid muscle in elderly patients after hip fracture surgery: Comparison of ultrasound images with a focus on swallowing function.

The purpose of this study was to clarify, using ultrasound imaging, (1) whether the area and contraction of GH change in elderly patients after hip fracture surgery and (2) whether the changes in the area and contraction of GH are related to decline in swallowing function. The participants were 21 female patients over 65 years of age who underwent hip fracture surgery. The patients were divided into two groups based on the results of swallowing assessment by water drinking: One with normal swallowing function (NSF) and the other with suspected decline in swallowing function (DSF). Sagittal cross-sectional area (SA) of GH at rest and the shortening rate (SR) of GH upon contraction during swallowing were compared at two time points: immediately and 2 weeks after surgery. Wilcoxon signed-rank test was used for intra-group comparisons, and Mann-Whitney U-test was used for between-group comparisons. SA of GH decreased significantly at 2 weeks after surgery in both groups, regardless of their swallowing function. In the intra-group comparison, SR significantly decreased (worsened) only in DSF group. SR at 2 weeks after surgery was significantly higher in NSF than in the DSF. In the inter-group comparison, DSF showed a significantly smaller (worse) change of SR than NSF in 2 weeks after surgery. Decrease in muscle mass, or atrophy, of GH observed in both NSF and DSF, did not coincide with the post-operative change in GH contraction of the two groups. The results suggest the importance of continuous swallowing assessment in the elderly individuals during their perioperative period.

Long-Term Axial Length Shortening in Myopic Orthokeratology: Incident Probability, Time Course, and Influencing Factors.

Long-term axial length (AL) shortening in myopia is uncommon but noteworthy. Current understanding on the condition is limited due to difficulties in case collection. The study reported percentage, probability, and time course of long-term AL shortening in myopic orthokeratology based on a large database. This study reviewed 142,091 medical records from 29,825 subjects in a single-hospital orthokeratology database that were collected over 10years. Long-term AL shortening was defined as a change in AL of -0.1mm or less at any follow-up beyond 1year. Incident probability was calculated based on multivariate logistic regression. Time course was estimated using mixed-effect regression model. A total of 10,093 subjects (mean initial age, 11.70 ± 2.52years; 58.8% female) with 80,778 visits were included. The number of subjects experienced long-term AL shortening was 1,662 (16.47%; 95% confidence interval, 15.75%-17.21%). Initial age showed significant impact on the incident occurrence (OR, 1.37; 95% confidence interval, 1.34-1.40; P < 0.001). The estimated probability of AL shortening was approximately 2% for subjects with initial age of 6years and 50% for those aged 18. Among the 1662 AL shortening cases, the median magnitude of the maximum AL reduction was 0.19mm. The shortening process mostly occurred within the initial 2years. Subject characteristics had limited associations with the shortening rate. Long-term AL shortening is possible in subjects receiving myopic orthokeratology. Although age notably affect the incident probability, the time course seems to not vary significantly.