Predicting 30-day unplanned hospital readmission after revision total knee arthroplasty: machine learning model analysis of a national patient cohort.

Revision total knee arthroplasty (TKA) is associated with a higher risk of readmission than primary TKA. Identifying individual patients predisposed to readmission can facilitate proactive optimization and increase care efficiency. This study developed machine learning (ML) models to predict unplanned readmission following revision TKA using a national-scale patient dataset. A total of 17,443 revision TKA cases (2013-2020) were acquired from the ACS NSQIP database. Four ML models (artificial neural networks, random forest, histogram-based gradient boosting, and k-nearest neighbor) were developed on relevant patient variables to predict readmission following revision TKA. The length of stay, operation time, body mass index (BMI), and laboratory test results were the strongest predictors of readmission. Histogram-based gradient boosting was the best performer in distinguishing readmission (AUC: 0.95) and estimating the readmission probability for individual patients (calibration slope: 1.13; calibration intercept: -0.00; Brier score: 0.064). All models produced higher net benefit than the default strategies of treating all or no patients, supporting the clinical utility of the models. ML demonstrated excellent performance for the prediction of readmission following revision TKA. Optimization of important predictors highlighted by our model may decrease preventable hospital readmission following surgery, thereby leading to reduced financial burden and improved patient satisfaction.

Custom orthotic design by integrating 3D scanning and subject-specific FE modelling workflow.

The finite element (FE) foot model can help estimate pathomechanics and improve the customized foot orthoses design. However, the procedure of developing FE models can be time-consuming and costly. This study aimed to develop a subject-specific scaled foot modelling workflow for the foot orthoses design based on the scanned foot surface data. Six participants (twelve feet) were collected for the foot finite element modelling. The subject-specific surface-based finite element model (SFEM) was established by incorporating the scanned foot surface and scaled foot bone geometries. The geometric deviations between the scaled and the scanned foot surfaces were calculated. The SFEM model was adopted to predict barefoot and foot-orthosis interface pressures. The averaged distances between the scaled and scanned foot surfaces were 0.23 ± 0.09 mm. There was no significant difference for the hallux, medial forefoot, middle forefoot, midfoot, medial hindfoot, and lateral hindfoot, except for the lateral forefoot region (p = 0.045). The SFEM model evaluated slightly higher foot-orthoses interface pressure values than measured, with a maximum deviation of 7.1%. These results indicated that the SFEM technique could predict the barefoot and foot-orthoses interface pressure, which has the potential to expedite the process of orthotic design and optimization.

The effects of alteration in muscle activation on the iliotibial band during an exhaustive run.

PURPOSE: Long exhausted running causes pain at the lateral femoral epicondyle for some runners. The pain has been revealed to be related to the behavior of the iliotibial band (ITB) during running. The purpose of this study is to examine the effects of in-series musculature on the behavior of the ITB in healthy participants during an exhaustive run. METHODS: Twenty-five healthy participants (15 males, 10 females) were recruited in the current study. All participants performed a 30-minute exhaustive run at a self-selected speed with laboratory-provided footwear. Muscle activities of ITB-related muscles including tensor fascia latae (TFL), gluteus maximus (Gmax), gluteus medius (Gmed), biceps femoris (BF), and vastus lateralis (VL) were recorded using surface electromyography (EMG). RESULTS: Maximum amplitudes at the initial stage (the first minute), the mid stage (the 15-minute), and the end stage (the 30-minute) were compared during the exhaustive running. Significant decreases (p < 0.05) were observed in the maximum amplitudes of the TFL, Gmax, Gmed, and BF at the mid (decreased by ~ 15%) and end (decreased by ~ 30%) stages compared to the initial stage. The onset and the offset remained unaltered during the running (p ≥ 0.05). CONCLUSION: The behavior of the healthy ITB might be altered due to the activities of the in-series musculature. Excessive compression forces might be applied to the lateral femoral epicondyle from the ITB to provide stability for the knee joint during an exhaustive run. The findings could provide a basic understanding of the behavior of healthy ITB.

Effects of Attrition Shoes on Balance Control Ability and Postural Stability Following a Single-Leg Drop Jump Landing.

The purpose of the study is to determine the influence of lateral-heel-worn shoes (LHWS) on balance control ability through the single-leg drop jump test. The results could be beneficial by preventing lower limb injuries. Eighteen healthy participants performed the single-leg drop jump test. Times to stabilization for ground reaction forces (TTSG) in the anterior/posterior, medial/lateral, and vertical directions were calculated to quantify dynamic balance control ability. Outcome variables of the center of pressure (COP) were used to examine the main effect of LHWS during the static phase. The postural control ability was assessed through time to stabilization for the center of mass (TTSC) in the three directions. TTSG and TTSC for the LHWS group were found to be longer than those for the new shoes (NS) group in the M/L direction (p < 0.05). An increase in the TTS revealed an increased risk of falls during physical activities. However, no significant effects for both TTSG and TTSC were found in the other two directions between LHWS and NS groups. A static phase was cropped using TTSG for each trial, which indicated a phase after participants obtained balance. Outcome measures derived from COP showed no significant effects in the static phase. In conclusion, LHWS weakened balance control ability and postural stability in the M/L direction when compared to the NS group. During the static phase, no significant differences were found between the LHWS group and the NS group in balance control ability and postural stability. Consequently, lateral-worn shoes might increase the risk of fall injuries. The results could serve as an evaluation of shoe degradation for individuals with the aim of avoiding the risk of falls.

Effects of prolonged brisk walking induced lower limb muscle fatigue on the changes of gait parameters in older adults.

BACKGROUND: Lower extremity muscle fatigue affects gait stability and increases the probability of injuries in the elderly. RESEARCH QUESTION: How does prolonged walking-induced fatigue affect lower limb muscle activity, plantar pressure distribution, and tripping risk? METHODS: Eighteen elderly adults walked fast on a treadmill for 60 minutes at a fixed speed. The plantar pressure was measured with an in-shoe monitoring system, eight lower limb muscles were monitored using surface electromyography, and foot movements were tracked by a motion capture analysis system. The above data and participants' subjective fatigue level feedback were collected every 5 minutes. Statistical analysis used the Friedman one-way repeated measures analysis of variance by ranks test followed by Wilcoxon signed-ranks test with Benjamini-Hochberg stepwise correction. RESULTS: The subjective reported fatigue on the Borg scale increased gradually from 1 to 6 (p = 0.001) during the 60 minutes, while the EMG amplitude of vastus medialis significant decreased (p = 0.013). The results of plantar pressure demonstrated that the distribution of load and impulse shifted medially in both the heel and arch regions while shifted laterally in both the toes and metatarsal regions. The significantly increased contact area supports this shift at the medial arch (p = 0.036, increased by 6.94%, the 60th minute vs. the baseline). The symmetry of medial-lateral plantar force increased at the toes, metatarsal, and arch regions. The significantly increased parameters also include the swing time and contact time. The minimum foot clearance was reduced, increasing tripping probability, not significantly, though. SIGNIFICANCE: This study facilitates a better understanding of changes in lower limb muscle activity and gait parameters during prolonged fast walking. Besides, this study has good guiding significance for developing smart devices based on plantar force, inertial measurement units, and EMG sensors to monitor changes in muscle activation in real-time and prevent tripping.

Architecture of the cytoplasmic face of the nuclear pore.

INTRODUCTION The subcellular compartmentalization of eukaryotic cells requires selective transport of folded proteins and protein-nucleic acid complexes. Embedded in nuclear envelope pores, which are generated by the circumscribed fusion of the inner and outer nuclear membranes, nuclear pore complexes (NPCs) are the sole bidirectional gateways for nucleocytoplasmic transport. The ~110-MDa human NPC is an ~1000-protein assembly that comprises multiple copies of ~34 different proteins, collectively termed nucleoporins. The symmetric core of the NPC is composed of an inner ring encircling the central transport channel and outer rings formed by Y­shaped coat nucleoporin complexes (CNCs) anchored atop both sides of the nuclear envelope. The outer rings are decorated with compartment­specific asymmetric nuclear basket and cytoplasmic filament nucleoporins, which establish transport directionality and provide docking sites for transport factors and the small guanosine triphosphatase Ran. The cytoplasmic filament nucleoporins also play an essential role in the irreversible remodeling of messenger ribonucleoprotein particles (mRNPs) as they exit the central transport channel. Unsurprisingly, the NPC's cytoplasmic face represents a hotspot for disease­associated mutations and is commonly targeted by viral virulence factors. RATIONALE Previous studies established a near-atomic composite structure of the human NPC's symmetric core by combining (i) biochemical reconstitution to elucidate the interaction network between symmetric nucleoporins, (ii) crystal and single-particle cryo-electron microscopy structure determination of nucleoporins and nucleoporin complexes to reveal their three-dimensional shape and the molecular details of their interactions, (iii) quantitative docking in cryo-electron tomography (cryo-ET) maps of the intact human NPC to uncover nucleoporin stoichiometry and positioning, and (iv) cell­based assays to validate the physiological relevance of the biochemical and structural findings. In this work, we extended our approach to the cytoplasmic filament nucleoporins to reveal the near-atomic architecture of the cytoplasmic face of the human NPC. RESULTS Using biochemical reconstitution, we elucidated the protein-protein and protein-RNA interaction networks of the human and Chaetomium thermophilum cytoplasmic filament nucleoporins, establishing an evolutionarily conserved heterohexameric cytoplasmic filament nucleoporin complex (CFNC) held together by a central heterotrimeric coiled­coil hub that tethers two separate mRNP­remodeling complexes. Further biochemical analysis and determination of a series of crystal structures revealed that the metazoan­specific cytoplasmic filament nucleoporin NUP358 is composed of 16 distinct domains, including an N­terminal S­shaped α­helical solenoid followed by a coiled­coil oligomerization element, numerous Ran­interacting domains, an E3 ligase domain, and a C­terminal prolyl­isomerase domain. Physiologically validated quantitative docking into cryo-ET maps of the intact human NPC revealed that pentameric NUP358 bundles, conjoined by the oligomerization element, are anchored through their N­terminal domains to the central stalk regions of the CNC, projecting flexibly attached domains as far as ~600 Å into the cytoplasm. Using cell­based assays, we demonstrated that NUP358 is dispensable for the architectural integrity of the assembled interphase NPC and RNA export but is required for efficient translation. After NUP358 assignment, the remaining 4-shaped cryo­ET density matched the dimensions of the CFNC coiled­coil hub, in close proximity to an outer-ring NUP93. Whereas the N-terminal NUP93 assembly sensor motif anchors the properly assembled related coiled­coil channel nucleoporin heterotrimer to the inner ring, biochemical reconstitution confirmed that the NUP93 assembly sensor is reused in anchoring the CFNC to the cytoplasmic face of the human NPC. By contrast, two C. thermophilum CFNCs are anchored by a divergent mechanism that involves assembly sensors located in unstructured portions of two CNC nucleoporins. Whereas unassigned cryo­ET density occupies the NUP358 and CFNC binding sites on the nuclear face, docking of the nuclear basket component ELYS established that the equivalent position on the cytoplasmic face is unoccupied, suggesting that mechanisms other than steric competition promote asymmetric distribution of nucleoporins. CONCLUSION We have substantially advanced the biochemical and structural characterization of the asymmetric nucleoporins' architecture and attachment at the cytoplasmic and nuclear faces of the NPC. Our near­atomic composite structure of the human NPC's cytoplasmic face provides a biochemical and structural framework for elucidating the molecular basis of mRNP remodeling, viral virulence factor interference with NPC function, and the underlying mechanisms of nucleoporin diseases at the cytoplasmic face of the NPC. [Figure: see text].

Different Design Feature Combinations of Flatfoot Orthosis on Plantar Fascia Strain and Plantar Pressure: A Muscle-Driven Finite Element Analysis With Taguchi Method.

Customized foot orthosis is commonly used to modify foot posture and relieve foot pain for adult acquired flexible flatfoot. However, systematic investigation of the influence of foot orthotic design parameter combination on the internal foot mechanics remains scarce. This study aimed to investigate the biomechanical effects of different combinations of foot orthoses design features through a muscle-driven flatfoot finite element model. A flatfoot-orthosis finite element model was constructed by considering the three-dimensional geometry of plantar fascia. The plantar fascia model accounted for the interaction with the bulk soft tissue. The Taguchi approach was adopted to analyze the significance of four design factors combination (arch support height, medial posting inclination, heel cup height, and material stiffness). Predicted plantar pressure and plantar fascia strains in different design combinations at the midstance instant were reported. The results indicated that the foot orthosis with higher arch support (45.7%) and medial inclination angle (25.5%) effectively reduced peak plantar pressure. For the proximal plantar fascia strain, arch support (41.8%) and material stiffness (37%) were strong influencing factors. Specifically, higher arch support and softer material decreased the peak plantar fascia strain. The plantar pressure and plantar fascia loading were sensitive to the arch support feature. The proposed statistics-based finite element flatfoot model could assist the insole optimization and evaluation for individuals with flatfoot.

Effects of Attrition Shoes on Kinematics and Kinetics of Lower Limb Joints During Walking.

Shoe attrition is inevitable as wearing time increases, which may produce diverse influences on kinematics and kinetics of lower limb joints. Excessive attrition may change support alignment and lead to deleterious impacts on the joints. The study identifies the biomechanical influences of aging shoes on lower limb joints. The shoes in the experiment were manually worn in the lateral heel. Nineteen healthy participants, including thirteen males and six females, were recruited to conduct walking experiments wearing attrition shoes (AS) and new shoes (NS) with a random order. A Vicon motion analysis system was used to collect kinematic data and ground reaction force. Kinematic and kinetic parameters of the hip, knee, and ankle joints were calculated using the Anybody Musculoskeletal Model and compared between the two conditions, AS and NS. The results showed that wearing an attrition shoe decreased the plantarflexion angle and plantarflexion moment of the ankle joint, while significantly increasing the magnitude of the first peak of the knee adduction moment and hip abduction moment and hip internal rotation moment (p < .05). The results of the study implied that wearing attrition shoes is not recommended for those people with knee problems due to increase in medial loading.

Association of RanGAP to nuclear pore complex component, RanBP2/Nup358, is required for pupal development in Drosophila.

Ran's GTPase-activating protein (RanGAP) is tethered to the nuclear envelope (NE) in multicellular organisms. We investigated the consequences of RanGAP localization in human tissue culture cells and Drosophila. In tissue culture cells, disruption of RanGAP1 NE localization surprisingly has neither obvious impacts on viability nor nucleocytoplasmic transport of a model substrate. In Drosophila, we identified a region within nucleoporin dmRanBP2 required for direct tethering of dmRanGAP to the NE. A dmRanBP2 mutant lacking this region shows no apparent growth defects during larval stages but arrests at the early pupal stage. A direct fusion of dmRanGAP to the dmRanBP2 mutant rescues this arrest, indicating that dmRanGAP recruitment to dmRanBP2 per se is necessary for the pupal ecdysis sequence. Our results indicate that while the NE localization of RanGAP is widely conserved in multicellular organisms, the targeting mechanisms are not. Further, we find a requirement for this localization during pupal development.

Distinct roles of nuclear basket proteins in directing the passage of mRNA through the nuclear pore.

The in vivo characterization of the exact copy number and the specific function of each composite protein within the nuclear pore complex (NPC) remains both desirable and challenging. Through the implementation of live-cell high-speed super-resolution single-molecule microscopy, we first quantified the native copies of nuclear basket (BSK) proteins (Nup153, Nup50, and Tpr) prior to knocking them down in a highly specific manner via an auxin-inducible degron strategy. Second, we determined the specific roles that BSK proteins play in the nuclear export kinetics of model messenger RNA (mRNA) substrates. Finally, the three-dimensional (3D) nuclear export routes of these mRNA substrates through native NPCs in the absence of specific BSK proteins were obtained and further validated via postlocalization computational simulations. We found that these BSK proteins possess the stoichiometric ratio of 1:1:1 and play distinct roles in the nuclear export of mRNAs within live cells. The absence of Tpr from the NPC predominantly reduces the probability of nuclear mRNAs entering the NPC for export. Complete depletion of Nup153 and Nup50 results in an mRNA nuclear export efficiency decrease of approximately four folds. mRNAs can gain their maximum successful export efficiency as the copy number of Nup153 increased from zero to only half the full complement natively within the NPC. Lastly, the absence of Tpr or Nup153 seems to alter the 3D export routes of mRNAs as they pass through the NPC. However, the removal of Nup50 alone has almost no impact upon mRNA export route and kinetics.

Suc Khoe là Hanh Phúc (Health is Happiness): promoting mammography and pap test adherence among Vietnamese nail salon workers.

Vietnamese nail salon workers have low cancer screening rates and confront multiple socioeconomic disparities as immigrants to the US. The Suc Khoe là Hanh Phúc (Vietnamese for "Health is Happiness") program was adapted to the cultural and work needs of this population and implemented at nail salons to increase cancer screening adherence. A total of 186 study participants were recruited from 59 nail salons in a neighborhood with mostly Asian population. After being pretested, workers were enrolled in a cancer education session delivered by Vietnamese lay health workers. Non-adherent cases were offered navigation to cancer screening services to a local federally qualified health center. Participants completed a posttest survey five months, on average. At posttest, navigated non-adherent participants were more likely to report a recent Pap test compared to cases not navigated (83.8% vs. 50.0%), an effect not observed for mammography uptake (77.3% vs. 71.4%). Time in the US, marital status, insurance status, having a primary care provider and/or a gynecologist were significantly associated with cancer screening adherence. Low rates of adherence to cancer screening among Vietnamese nail salons workers can be improved by community based programs addressing cultural and work-related barriers confronted by this population.

Nucleoporin TPR is an integral component of the TREX-2 mRNA export pathway.

Nuclear pore complexes (NPCs) are important for cellular functions beyond nucleocytoplasmic trafficking, including genome organization and gene expression. This multi-faceted nature and the slow turnover of NPC components complicates investigations of how individual nucleoporins act in these diverse processes. To address this question, we apply an Auxin-Induced Degron (AID) system to distinguish roles of basket nucleoporins NUP153, NUP50 and TPR. Acute depletion of TPR causes rapid and pronounced changes in transcriptomic profiles. These changes are dissimilar to shifts observed after loss of NUP153 or NUP50, but closely related to changes caused by depletion of mRNA export receptor NXF1 or the GANP subunit of the TRanscription-EXport-2 (TREX-2) mRNA export complex. Moreover, TPR depletion disrupts association of TREX-2 subunits (GANP, PCID2, ENY2) to NPCs and results in abnormal RNA transcription and export. Our findings demonstrate a unique and pivotal role of TPR in gene expression through TREX-2- and/or NXF1-dependent mRNA turnover.

RanBP1 controls the Ran pathway in mammalian cells through regulation of mitotic RCC1 dynamics.

The Ran GTPase plays critical roles in multiple cellular processes including interphase nucleocytoplasmic transport and mitotic spindle assembly. During mitosis in mammalian cells, GTP-bound Ran (Ran-GTP) is concentrated near mitotic chromatin while GDP-bound Ran (Ran-GDP) is more abundant distal to chromosomes. This pattern spatially controls spindle formation because Ran-GTP locally releases spindle assembly factors (SAFs), such as Hepatoma Up-Regulated Protein (HURP), from inhibitory interactions near chromosomes. Regulator of Chromatin Condensation 1 (RCC1) is Ran's chromatin-bound exchange factor, and RanBP1 is a conserved Ran-GTP-binding protein that has been implicated as a mitotic regulator of RCC1 in embryonic systems. Here, we show that RanBP1 controls mitotic RCC1 dynamics in human somatic tissue culture cells. In addition, we observed the re-localization of HURP in metaphase cells after RanBP1 degradation, consistent with the idea that altered RCC1 dynamics functionally modulate SAF activities. Together, our findings reveal an important mitotic role for RanBP1 in human somatic cells, controlling the spatial distribution and magnitude of mitotic Ran-GTP production and thereby ensuring the accurate execution of Ran-dependent mitotic events. ABBREVIATIONS: AID: Auxin-induced degron; FLIP: Fluorescence loss in photobleaching; FRAP: Fluorescence recovery after photobleaching; GDP: guanosine diphosphate; GTP: guanosine triphosphate; HURP: Hepatoma Up-Regulated Protein; NE: nuclear envelope; NEBD: Nuclear Envelope Breakdown; RanBP1: Ran-binding protein 1; RanGAP1: Ran GTPase-Activating Protein 1; RCC1: Regulator of Chromatin Condensation 1; RRR complex: RCC1/Ran/RanBP1 heterotrimeric complex; SAF: Spindle Assembly Factor; TIR1: Transport Inhibitor Response 1 protein; XEE: Xenopus egg extract.

Enhanced oxygen sensing properties of Pt(II) complex and dye entrapped core-shell silica nanoparticles embedded in sol-gel matrix.

This paper presents a highly sensitive oxygen sensor that comprises an optical fiber coated at one end with platinum(II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) and PtTFPP entrapped core-shell silica nanoparticles embedded in an n-octyltriethoxysilane (Octyl-triEOS)/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio I(0)/I(100), where I(0) and I(100) represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results show that the oxygen sensor has a sensitivity (I(0)/I(100)) of 166. The response time was 1.3s when switching from pure nitrogen to pure oxygen, and 18.6s when switching in the reverse direction. The experimental results show that compared to oxygen sensors based on PtTFPP, PtOEP, or Ru(dpp)(3)(2+) dyes, the proposed optical fiber oxygen sensor has the highest sensitivity. In addition to the increased surface area per unit mass of the sensing surface, the dye entrapped in the core of silica nanoparticles also increases the sensitivity because a substantial number of aerial oxygen molecules penetrate the porous silica shell. The dye entrapped core-shell nanoparticles is more prone to oxygen quenching.