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Purposes: The magnesium alloy bionic cannulated screw (MABCS) was designed in a previous study promoting cortical-cancellous biphasic healing of femoral neck fractures. The main purpose was to analyze the bore diameters that satisfy the torsion standards and further analyze the optimal pore and implantation direction for stabilizing femoral neck fractures. Methods: The MABCS design with bionic holes with a screw diameter of less than 20% met the torsion standard for metal screws. The MABCS was utilized to repair the femoral neck fracture via Abaqus 6.14 software, which simulated the various stages of fracture healing to identify the optimal biomechanical environment for bionic hole size (5%, 10%, 15%, and 20%) and implantation direction (0°, 45°, 90°, and 135°). Results: The stress distribution of the MABCS fracture fixation model is significantly improved with an implantation orientation of 90°. The MABCS with a bionic hole and a screw diameter of 10% provides optimal stress distribution compared with the bionic cannulated screw with diameters of 5%, 15%, and 20%. In addition, the cannulated screw fixation model with a 10% bionic hole size has optimal bone stress distribution and better internal fixation than the MABCS fixation models with 5%, 15%, and 20% screw diameters. Conclusion: In summary, the MABCS with 10% screw diameter bionic holes has favorable biomechanical characteristics for stabilizing femoral neck fractures. This study provides a biomechanical foundation for further optimization of the bionic cannulated screw.

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Dangerous biological agents （DBAs） refer to microorganisms, toxins, and other biological substances that have the potential to cause significant harm to humans, animals, plants, and the environment. They are the primary target of the prevention and response in China's Biosafety Law, and it is of great importance to clarify the characteristics of DBAs in the Beijing suburban rivers for the insurance of the water safety in Beijing. The typical Beijing suburban rivers （Mangniu River, Chaohe River, and Baihe River） were selected, and the occurrence and distribution of DBAs concerning the molecular biology composition as the nucleic acid （antibiotic resistance genes, ARGs）, nucleic acid and proteins （viruses）, and intact cellular structures （pathogens） were determined based on the metagenomics. The results showed that there was a high abundance of multidrug-resistant ARGs in the water and substrates of the urban river； on average, they made up 74.11% ±6.82% of the total, and the abundance of aminoglycoside and MLS （macrolide-lincosamide-streptomycin）-resistant ARGs was the highest, but the predominant subtypes of ARGs were of low risk and had limited transmission potential. The viruses in the tributary mainly belonged to the phages, most of which were Kyanoviridae and Peduoviridae, with averages of 16.98% ±8.44% and 16.19% ±10.79%, respectively. Eukaryotic viral populations consisted mainly of members from the Mimiviridae and Phycodnaviridae families, with averages of 10.37% ±12.68% and 8.34% ±6.97%, respectively, whereas there were few viruses related to human and animal diseases. The pathogenic bacteria mainly contained Neisseria meningitidis, Brucella suis, Salmonella enterica, and Burkholderia pseudomalle, with averages of 19.17% ±3.63%, 12.76% ±2.88%, 11.22% ±1.95%, and 8.26% ±1.84%, respectively. The composition and abundance of pathogenic bacteria varied significantly among different tributaries and locations, possibly owing to water quality, pollution sources, environmental factors, and human activities. These findings can provide data support for the water safety management and biological risk control of Beijing suburban rivers.

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The dynamics of the composition and antibiotic resistance of the fecal coliform bacteria (FCB) in a typical wastewater treatment plant (WWTP) were investigated concerning the seasonal changes. Results showed that WWTP could remove the FCB concentration by 3∼5 logs within the effluent of 104∼105 CFU/L, but the antibiotic resistant rate of FCB species increased significantly after WWTP. The dominant FCB changed from Escherichia coli in the influent (∼73.0%) to Klebsiella pneumoniae in the effluent (∼53.3%) after WWTP, where the Escherichia coli was removed the most, while Klebsiella pneumoniae was the most persistent. The secondary tank removed the most of FCB (by 3∼4 logs) compared to other processes, but increased all the concerned antibiotic resistant rate. The potential super bugs of FCB community showing resistance to all the target antibiotics were selected in the biological treatment unit of WWTP. The FCB showed the highest multiple antibiotic resistance (92.9%) in total which even increased to 100% in the effluent. Klebsiella has the highest antibiotic resistant rate in FCB, with a multiple antibiotic resistance rate of 98.4%. These indicated that the Klebsiella pneumoniae not just Escherichia coli should be specially emphasized after WWTP concerning the health risk associated with FCB community.

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Purpose: Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed. Methods: In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement. Results: Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm). Conclusion: Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.

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Given the advancements in modern living standards and technological development, conventional smart devices have proven inadequate in meeting the demands for a high-quality lifestyle. Therefore, a revolution is necessary to overcome this impasse and facilitate the emergence of flexible electronics. Specifically, there is a growing focus on health detection, necessitating advanced flexible preparation technology for biosensor-based smart wearable devices. Nowadays, numerous flexible products are available on the market, such as electronic devices with flexible connections, bendable LED light arrays, and flexible radio frequency electronic tags for storing information. The manufacturing process of these devices is relatively straightforward, and their integration is uncomplicated. However, their functionality remains limited. Further research is necessary for the development of more intricate applications, such as intelligent wearables and energy storage systems. Taking smart wear as an example, it is worth noting that the current mainstream products on the market primarily consist of bracelet-type health testing equipment. They exhibit limited flexibility and can only be worn on the wrist for measurement purposes, which greatly limits their application diversity. Flexible energy storage and flexible display also face the same problem, so there is still a lot of room for development in the field of flexible electronics manufacturing. In this review, we provide a brief overview of the developmental history of flexible devices, systematically summarizing representative preparation methods and typical applications, identifying challenges, proposing solutions, and offering prospects for future development.

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PURPOSE: The study aimed to compare the perioperative complications, short-term clinical outcomes, patient-reported outcomes, and radiographic parameters of tibiofibular proximal osteotomy combined with absorbable spacer insertion (TPOASI) and open-wedge high tibial osteotomy (OWHTO) in a two year postoperative time period. METHODS: A total of 160 patients with Kellgren-Lawrence classification grade 3 medial compartmental knee OA were randomized to receive either TPOASI (n = 82) or OWHTO (n = 78). The primary and secondary outcomes were measured preoperatively, postoperatively, and at each follow-up examination. The primary outcomes were the between-group change in the Western Ontario and McMaster Universities Global score (WOMAC). Secondary measures included visual analog scale (VAS), radiographic parameters, American Knee Society Score (KSS), operation time, blood loss, length of incision, hospital stay, and relevant complications. Postoperative radiographic parameters, including the femorotibial angle (FTA), varus angle (VA), and joint line convergence angle (JLCA), were measured to evaluate the correction of varus deformity. RESULTS: No significant differences were found in the baseline data between the two groups. Both methods improved functional status and pain postoperatively. For primary outcomes of both groups, statistical difference was observed in WOMAC scores at the 6-month follow-up (P < 0.001). For secondary outcomes, no statistical difference was observed between the groups during the 2-year follow-up (P > 0.05). For TPOASI vs. OWHTO, the mean hospital stay (6.6 ± 1.3 days vs. 7.8 ± 2.1 days) was shorter (P < 0.001), and both blood loss (70.56 ± 35.58 vs. 174.00 ± 66.33 mL) and complication rate (3.7% vs. 12.8%) were significantly lower (P < 0.005 for both). CONCLUSIONS: Both approaches showed satisfactory functional outcomes and alleviated pain. However, TPOASI is a simple, feasible method with few complications, and it could be widely used.

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OBJECTIVE: To using finite element analysis to investigate the effects of the traditional titanium alloy Gamma nail and a biodegradable magnesium alloy bionic Gamma nail for treating intertrochanteric fractures. METHODS: Computed tomography images of an adult male volunteer of appropriate age and in good physical condition were used to establish a three-dimensional model of the proximal femur. Then, a model of a type 31A1 intertrochanteric fracture of the proximal femur was established, and the traditional titanium alloy Gamma nails and biodegradable magnesium alloy bionic Gamma nails were used for fixation, respectively. The von Mises stress, the maximum principal stress, and the minimum principal stress were calculated to evaluate the effect of bone ingrowth on stress distribution of the proximal femur after fixation. RESULTS: In the intact model, the maximum stress was 5.8 MPa, the minimum stress was -11.7 MPa, and the von Mises stress was 11.4 MPa. The maximum principal stress distribution of the cancellous bone in the intact model appears in a position consistent with the growth direction of the principal and secondary tensile zones. After traditional Gamma nail healing, the maximum stress was 32 MPa, the minimum stress was -23.5 MPa, and the von Mises stress was 31.3 MPa. The stress concentration was quite obvious compared with the intact model. It was assumed that the nail would biodegrade completely within 12 months postoperatively. The maximum stress was 18.7 MPa, the minimum stress was -12.6 MPa, and the von Mises stress was 14.0 MPa. For the minimum principal stress, the region of minimum stress value less than -10 MPa was significantly improved compared with the traditional titanium alloy Gamma nail models. Meanwhile, the stress distribution of the bionic Gamma nail model in the proximal femur was closer to that of the intact bone, which significantly reduced the stress concentration of the implant. CONCLUSION: The biodegradable magnesium alloy bionic Gamma nail implant can improve the stress distribution of fractured bone close to that of intact bone while reducing the risk of postoperative complications associated with traditional internal fixation techniques, and it has promising clinical value in the future.

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We apply a three-step sequential procedure to estimate the change-point of count time series. Under certain regularity conditions, the estimator of change-point converges in distribution to the location of the maxima of a two-sided random walk. We derive a closed-form approximating distribution for the maxima of the two-sided random walk based on the invariance principle for the strong mixing processes, so that the statistical inference for the true change-point can be carried out. It is for the first time that such properties are provided for integer-valued time series models. Moreover, we show that the proposed procedure is applicable for the integer-valued autoregressive conditional heteroskedastic (INARCH) models with Poisson or negative binomial conditional distribution. In simulation studies, the proposed procedure is shown to perform well in locating the change-point of INARCH models. And, the procedure is further illustrated with empirical data of weekly robbery counts in two neighborhoods of Baltimore City.

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Femoral shaft fracture is one of the most common types of fracture encountered in the clinic. For certain complex femoral shaft fractures, the traditional intramedullary nail may not provide sufficient stability. Therefore, novel intramedullary nail systems are required. The femur 3D model and the internal fixation model were designed using Mimics 17.0 (Materialise), Geomagic Studio 2012 (Raindrop) and Solidwork 2016 (Dassault) software. The validity of the models was verified through comparison with previous data in silico. To further simulate the comminuted femoral shaft fracture, the novel and traditional type of intramedullary nail system were included in the finite element analysis with the software. The displacement and stress distribution of the two internal fixations were compared using Abaqus 6.14 (Dassault) software. The effectiveness of the model was verified. The stress at the fixed end of the novel intramedullary nail system was greater than that at the fixed end of the traditional intramedullary nail system. However, the displacement of the novel intramedullary nail method was smaller than that of the traditional intramedullary nail. The novel intramedullary nail system features good stability and stress stimulation at the broken end, which is beneficial for bone healing. The present study may provide a theoretical basis for the selection of a means of internal fixation in the clinic.

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BACKGROUND: To compare the stability of sacroiliac joint disruption fixed with three kinds of internal fixation using both biomechanical test and finite element analysis. METHODS: Five embalmed specimens of an adult were used. The symphysis pubis rupture and left sacroiliac joint disruption were created. The symphysis pubis was stabilized with a five-hole plate. The sacroiliac joint disruption was fixed with three kinds of internal fixation in a randomized design. Displacements of the whole specimen and shifts in the gap were recorded. Three-dimensional finite element models of the pelvis, the pelvis with symphysis pubis rupture and left sacroiliac joint disruption, and three kinds of internal fixation techniques were created and analyzed. RESULTS: Under the vertical load, the displacements and shifts in the gap of the pelvis fixed with minimally invasive adjustable plate (MIAP) combined with one iliosacral (IS) screw were the smallest, and the average displacements of the pelvis fixed with an anterior plate were the largest one. The differences among them were significant. In finite element analysis and MIAP combined with one IS screw fixation showed relatively best fixation stability and lowest risks of implant failure than two IS screws fixation and anterior plate fixation. CONCLUSION: The stability of sacroiliac joint disruption fixed with MIAP combined with one IS screw is better than that fixed with two IS screws and anterior plate under vertical load.

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BACKGROUND Clinical studies indicate that in total ankle arthroplasty, postoperative implant subsidence and medial tilt become two significant concerns of the ankle replacement system, and which are associated with the contact between the bones and the talar component. Up to now, little attention has focused on the contact between the bones and the talar component. MATERIAL AND METHODS In order to address implant subsidence and medial tilt, one three-dimensional finite element model of contact between the bone and the talar components was built with the material properties of the cancellous bone interpolated from the experimental data, which represents variation of material properties through the cancellous bones. The finite element model was used to study the following: variation of the Young's modulus of the bones, stiffness of the talar component, loading direction, and loading magnitude with the implant subsidence. RESULTS The computational results reveal that a variety of Young's modulus of the cancellous bones causes the medial tilting of the talar component and that big plastic strains are associated with tilting. The implant subsidence increases from 0.169 mm to 0.269 mm when the loading changes from 272 kg to 408 kg. However, to the contrary, the implant subsidence decreases from 0.2676 mm to 0.1783 mm when Young's modulus of the bones increases 50%. However, the implant subsidence shows little change with a different Young's modulus of the talar component from 88 GPa to 132 GPa. CONCLUSIONS Our study indicates that a variety of different Young's modulus of the cancellous bones cause the medial tilting of the talar component. To solve subsidence and tilting, both the contact area and the variation of material properties should be taken into account.

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BACKGROUND: Unstable pelvic fractures are complex and serious injuries. Selection of a fixation method for these fractures remains a challenging problem for orthopedic surgeons. This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws and minimally invasive adjustable plate (MIAP) combined with one IS screw. METHODS: This study was a biomechanical experiment. Six embalmed specimens of the adult pelvis were used. The soft tissue was removed from the specimens, and the spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were made on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with two kinds of internal fixation in turn. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500 N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor. STATISTICAL ANALYSIS USED: Paired-samples t-test. RESULTS: Under the vertical load of 100, 200, 300, 400, and 500 N, the average displacement of the specimens fixed with MIAP combined with one IS screw was 0.46, 0.735, 1.377, 1.823, and 2.215 mm, respectively, which was significantly lower than that of specimens fixed with two IS screws under corresponding load (P < 0.05). Under the vertical load of 500 N, the shift in the fracture gap of specimens fixed with MIAP combined with one IS screw was 0.261 ± 0.095 mm, and that of specimens fixed with two IS screws was 0.809 ± 0.170 mm. The difference was significant (P < 0.05). CONCLUSION: The stability of Tile C pelvic fractures fixed with MIAP combined with one IS screw was better than that fixed with two IS screws.

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