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SUMMARY: The aim of this study was to determine the sensitivity of different methods of partialization, in terms of different body component indices in relation to indicators of strength and explosiveness. The research involved 187 subjects who were divided into two groups based on sex. This research consisted of measuring body composition characteristics by multichannel bioimpedance analysis (BIA) InBody 720, as well as contractile characteristics of different muscle groups with tenziometric Dinamometry method. Based on the results of the factor analysis we found that regardless of the sex the most sensitive variable for partialization of absolute body isometric strength variable (ABiS) is partialization by allometric scaling (0.964 for females and 0.947 for males explained factor variance). However, in the case of absolute body isometric explosiveness (ABiE), the results of this study have demonstrated that partialization relative to skeletal muscle mass according to the body longitudinality - skeletal muscle mass index (SMMI) is the methodological choice disregarding the sex (0.982 for females and 0.980 for males explained factor variance). The results of the study have shown that for the purpose of scaling the maximal strength relative to body composition, the allometric method can be considered as a choice, while for the partialization of maximal isometric explosiveness skeletal muscle mass index is the best choice insensitive of the sex.
El objetivo de este estudio fue determinar la sensibilidad de distintos métodos de parcialización, en términos de diferentes índices de componentes corporales en relación a los indicadores de fuerza y explosividad. En la investigación participaron 187 sujetos que se dividieron según el sexo en dos grupos. Esta investigación consistió en medir las características de composición corporal mediante análisis de bioimpedancia multicanal (BIA) InBody 720, así como las características contráctiles de diferentes grupos musculares con el método de Dinamometría tenciométrica. Con base en los resultados del análisis factorial, encontramos que, independientemente del sexo, la variable más sensible para la parcialización de la variable de fuerza isométrica corporal absoluta (ABiS) fue la parcialización mediante escala alométrica (0,964 para las mujeres y 0,947 para los hombres). Sin embargo, en el caso de la explosividad isométrica corporal absoluta (ABiE), los resultados de este estudio han demostrado que la parcialización relativa a la masa del músculo esquelético según la longitudinalidad del cuerpo - índice de masa del músculo esquelético (SMMI) es la opción metodológica sin tener en cuenta el sexo (0,982 para las mujeres y 0,980 para los hombres). Los resultados del estudio han demostrado que para escalar la fuerza máxima en relación con la composición corporal, el método alométrico puede considerarse como una opción, mientras que para la parcialización de la explosividad isométrica máxima, el índice de masa del músculo esquelético es la mejor opción independiente del sexo.
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Humans , Male , Female , Adult , Body Composition , Muscle Strength , Isometric Contraction , Body Mass Index , Factor Analysis, Statistical , Electric ImpedanceABSTRACT
ObjectiveTo investigate risk factors for postoperative sore throat in patients with double-lumen endotracheal intubation. MethodsThe data used in this post-hoc analysis were prospectively collected from a randomized， controlled trial. Age from 18 to 65 years old， ASAI-Ⅲ patients undergoing general anesthesia with a double-lumen endotracheal tube were enrolled. The perioperative data collected retrospectively were as follows： gender， age， smoking history， endotracheal tube diameter， duration of endotracheal tube， dose of Sufentanil， use of Flurbiprofen Axetil， cough after extubation， etc..Dynamometer was applied to assess extubation force. According to occurrence of postoperative sore throat， patients were divided into two groups： those who experienced sore throats and those who did not. Comparative analysis and multivariate logistic regression analysis were performed to screen the risk factors. ROC curve was used for predicting the predictive value of risk factors. ResultsAmong the 163 patients ， 74 （45.4%） had postoperative sore throat vs 89 （54.6%） not had. Multivariate logistic regression showed female ［OR95%CI=3.83（1.73， 8.50）， P=0.000 1］ and extubation force ［OR95%CI=1.78（1.45， 2.17）， P＜0.001］ were independent risk factors for postoperative sore throat. AUC value showed the extubation force was 0.773［95%CI（0.701， 0.846）， P＜0.001］. Youden index was 0.447， and the cut-off valve of extubation force was 13N. ConclusionFemale and extubation force were risk factors for sore throat in patients with double lumen endotracheal intubation.
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Objective The biomechanical model for the musculoskeletal system of a human knee joint was established using a numerical simulation method.The kinematic and dynamic information captured during jumping motion simulated by the human dynamic model was used as driven data of the knee biomechanical model,followed by further analysis of the stress field distribution characteristics of the meniscus under different thermal-force coupling knee brace conditions.Methods Based on computed tomography and magnetic resonance imaging of the subject,a realistic human knee model,including bone,articular cartilage,meniscus,ligaments and peripheral soft tissues of the knee joint,was constructed.Furthermore,two gaits,namely taking-off and landing-on,of jumping motion with an increased risk of meniscus injuries were selected according to mechanical features in full-cycle jumping motion.Subsequently,the stress field characteristics of the knee meniscus under four different thermal-force coupling knee braces were analyzed,the changes of the peak stress of the meniscus and its stress concentration area were discussed,and the protective efficacy and mechanical basis of meniscal injuries and wearing knee braces were explored.Results The anterior part of the medial knee meniscus was a vulnerable area under concentrated stress.Under the knee brace thermal-force coupling condition,the stress concentration area of the medial meniscus was transferred from its narrow and weak anterior part to its wide and thick middle part,and the peak stress was also significantly reduced.The peak stress on the medial meniscus and that on the lateral meniscus were similar,indicating that the two parts of the meniscus bore the external load evenly,and the meniscus stress concentration area decreased.Conclusions Thermal-force coupling knee braces have good protective effects against knee meniscus injury.The numerical simulation provides theoretical support and technical guidance for the design of multifunctional thermal knee braces.
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Objective To conduct a comparative analysis of the biomechanical characteristics of the lower limbs during stair descent in patients with hemiplegia using different method to provide theoretical references for reducing fall risk during stair descent.Methods Ten healthy subjects and 20 patients with hemiplegia were selected,and their kinematic and dynamic data during stair descent were collected using the Qualisys Motion capture system and the Kistler three-dimensional dynamometer.Their biomechanical characteristics and fall risks were also analyzed.Results Compared with that of healthy subjects and patients that step on the healthy side(SHS),the range of motion(ROM)of the affected side in the lower-limb joints of patients that step on the affected side(SAS)was smaller.SHS reduced the flexion and extension ranges of the healthy side of the knee joint,and the ROM of the affected side in the lower-limb joints of SHS patients was greater than that of SAS patients.The ground reaction force(GRF)curve changes of SAS patients in left and right directions during stair descent were relatively consistent with those of normal subjects.The maximum vertical GRF of the affected side in SAS patients at the moment of landing was 1.05 times the body weight,whereas that of the healthy side was 1.25 times the body weight,which was lower than that of normal subjects(1.5 times the body weight).The maximum vertical GRF of the healthy side in SHS patients at the moment of landing was 1.85 times the body weight,which was higher than that of SAS patients and normal subjects.Conclusions Compared with that of SAS patients,the affected limb side of SHS patients has a greater ROM and vertical GRF at the moment of landing during stair descent,making SHS difficult to master.SAS is most consistent with the biomechanical characteristics during stair descent of patients with hemiplegia.
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Objective A finite element simulation analysis of a bracketless orthodontic appliance was carried out to determine the correction amount under different working conditions.A design scheme for the bracketless orthodontic appliance was also formulated to create an orthodontic appliance formed by the fused deposition process with a personalized orthodontic effect.Methods Combined with the computed tomography data of the patient,a tooth model was reversely reconstructed.The correction amount of the tooth under tilting,twisting,and translation working conditions was established using the finite element method.Materials with different elastic moduli were chosen to make three-dimensional(3D)shaped bracketless orthodonitc appliance,and the orthodontic force was measured.Results Different correction amounts could be designed according to different working conditions so that the orthodontic appliance had a personalized treatment effect.The orthodontic force of the bracketless orthodontic appliance increased with elastic modulus and thickness.Under the given working conditions,the orthodontic force was minimal(90 mN)when the orthodontic material was at the minimum(90 mN).The orthodontic force reached its maximum value when the orthodontic material was at the maximum(61.66 N).Conclusions According to the patient's tooth condition and the size of the orthodontic force required for each step of correction in the whole correction process,the design should consider bracketless orthodontics with different elastic moduli and thicknesses to treat deformed teeth to realize the effect of staged orthodontic correction.
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Objective:To investigate the effect of a visual walking training based on wearable cueing devices on ground reaction force of Parkinson's disease patients with freezing of gait. Method:Twenty-three PD with FOG(PD+FOG)were selected and twenty healthy controls(HC)were tested in gait laboratory.The experimental group was trained with wearable walking guide devices for 20 minutes,twice a day for one week.The Vicon 3D gait analysis system was used to collect the spatiotemporal parame-ters and the ground reaction force parameters of the non-dominant side and the dominant side including front-back peak,medial-lateral peak and the first vertical peak)of the experimental group and the control group be-fore and after training. Result:①After the intervention,the bilateral step length and velocity of patients in the experimental group in-creased signi ficantly(P＜0.05),while cadence,double stance phase decreased significantly(P＜0.05).After train-ing,there was no significant difference in the dominant step length,cadence and double stance phase between experimental group and control group(P＞0.05).②After the training,bilateral parameters(landing angles of hip joints,the maximum angles of ankle dorsiflexion and plantar flexion,and the ranges of motion of lower limb joints)in the experimental group increased significantly,while the landing angles of knee joints de-creased,and the stage of the first peak of ankle joints was delayed,with statistical significance(P＜0.05).Af-ter the training,knee joint landing angle,maximum ankle dorsiflexion angle,the first peak stage of ankle joint,lower limb joint range of motion had no significant difference between the experimental group and the control group in both sides(P＞0.05).③After the intervention,the front-back peak value and the first vertical peak of the bilateral ground reaction force in the experimental group were significantly increased(P＜0.05),while the medial-lateral peak value of the ground reaction force was significantly decreased(P＜0.05).Compared with the control group,there was no significant difference in the backward peak,medial peak of non-domi-nant side and parameters of the dominant side(P＞0.05). Conclusion:The visual walking training based on wearable walking guide devices improve the stability and consistency of gait of PD+FOG.
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Aiming at the problem of large force tracking errors caused by environmental stiffness changes when dual-arm robot is assisting in opening soft tissues in head and neck surgery,an adaptive admittance control strategy based on radial basis function(RBF)neural network is proposed for reducing force tracking error and improving system response speed.By using RBF neural network to adjust admittance parameters online during surgery,the adaptability of the robotic arm to different contact conditions and operation requirements is improved,thereby realizing fast and accurate force tracking.The simulation experiment introduces the adaptive admittance control strategy based on RBF neural network into the dual-arm force synchronous admittance control system and compares it with the traditional fixed-parameter admittance control to prove its contact force control effect under the condition of variable contact environment parameters.The results demonstrate that the adaptive admittance control strategy based on RBF neural network can effectively improve the force tracking accuracy,response speed and anti-interference capability of dual-arm surgical robot.
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Objective To assess the clinical effect of the Yiqi Huoxue Huazhuo therapy(the therapy for replenishing qi,activating blood and resolving turbidity)for the treatment of hepatic fibrosis in Wilson's disease(WD,also known as hepatolenticular degeneration).Methods Using retrospective research method,52 patients with liver fibrosis in WD of qi deficiency and blood stasis type were divided into 24 cases in the control group and 28 cases in the treatment group according to the treatment method.The control group was treated with conventional decopper therapy with western medicines,and the treatment group was treated with Chinese herbal decoction based on Yiqi Huoxue Huazhuo therapy together with conventional decopper therapy.Both groups were treated for a total of 4 weeks.Before and after the treatment,the two groups were observed in the changes of traditional Chinese medicine(TCM)syndrome scores,Unified Wilson's Disease Rating Scale(UWDRS)hepatic symptom scores,serum levels of liver fibrosis indicators of pre-collagen typeⅢ(PCⅢ),hyaluronic acid(HA),collagenⅣ(CⅣ),and laminin(LN),C-X-C motif chemokine ligand 10(CXCL10)level,and the point shear-wave elastography(pSWE)values of hepatic ultrasound based on acoustic radiation force impulse imaging(ARFI).After treatment,the clinical efficacy of the two groups was evaluated.Results(1)After 4 weeks of treatment,the total effective rate of the treatment group was 85.71%(24/28),while that of the control group was 54.17%(13/24),and the intergroup comparison(tested by chi-square test)showed that the therapeutic efficacy of the treatment group was significantly superior to that of the control group(P＜0.05).(2)After treatment,the TCM syndrome scores in both groups were decreased compared with those before treatment(P＜0.01),and the decrease of TCM syndrome scores in the treatment group was significantly superior to that in the control group(P＜0.05).(3)After treatment,the UWDRS liver symptom scores in the two groups were decreased compared with those before treatment(P＜0.01),but the difference was not statistically significant when comparing between the two groups after treatment(P＞0.05).(4)After treatment,serum levels of liver fibrosis indicators of HA,LN,CⅣ and PCⅢ in the treatment group were all decreased compared with those before treatment(P＜0.01),while in the control group only serum LN and PCⅢlevels were decreased(P＜0.05).The intergroup comparison showed that the decrease of serum HA,LN,and PCⅢlevels in the treatment group was superior to that in the control group(P＜0.05 or P＜0.01),while the decrease of serum CⅣlevel tended to be superior to that in the control group,but the difference was not statistically significant(P＞0.05).(5)After treatment,the serum chemokine CXCL10 level in the treatment group was significantly decreased compared with that before treatment(P＜0.01),while the level tended to decrease in the control group,but the difference was not statistically significant(P＞0.05).The intergroup comparison showed that the reduction of serum CXCL10 level in the treatment group was significantly superior to that in the control group(P＜0.05).(6)After treatment,the pSWE values of hepatic ultrasound in the two groups were lower than those before treatment(P＜0.01),and the reduction of pSWE values in treatment group was significantly superior to that of the control group(P＜0.01).Conclusion Yiqi Huoxue Huazhuo therapy can effectively reduce the TCM syndrome scores of WD patients,improve the UWDRS hepatic symptom scores,down-regulate the liver fibrosis indicator level and serum CXCL10 expression level,reduce the pSWE values of hepatic ultrasound,and enhance the clinical efficacy.
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Objective To investigate the effect of dynamic monitoring of occlusal force on the final therapeutic effect and the change of periodontal supporting tissue during combined periodontal orthodontic treatment.Methods The periodontal clinical index of 20 patients with traditional periodontal orthodontic treatment and 20 patients with combined periodontal orthodontic treatment assisted by T-Scan Ⅲ and Anycheck digital occlusion analysis system were compared before,during and after treatment,as well as the changes of bite force,bite time and tooth mobility in the experimental group.Results The depth of periodontal pocket(PD),loss of attachment(AL),bleeding index(BI)and tooth looseness were significantly reduced after combined periodontal orthodontic treatment in both groups.In the control group,the percentage of anterior and posterior biting force changed obviously,and the occlusion force balance was improved.Conclusion The combined treatment of periodontitis and orthodontics can improve the periodontal tissue of patients with periodontitis,and T-Scan system can observe and guide the adjustment of occlusal and better achieve occlusion force balance.
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Objective To explore the application effect of new improved 3D printing individualized guidance(3D psi)in total knee arthroplasty(TKA)for knee osteoarthritis(KOA).Methods A total of 100 patients with KOA in 920th Hospital of Joint Logistics Support Force,PLA from January 2021 to January 2022 were selected,and were divided into 2 groups of 50 patients each using the randomized numerical table method.The control group was treated with conventional TKA,and the study group was treated with new improved 3D psi assisted TKA.The operation conditions,postoperative rehabilitation,complications,prosthesis component position deviation,knee range of motion(ROM),lower limb force line parameters[coronal distal femoral mechanical axis lateral angle(mldfa),lower limb mechanical axis angle(HKA)],gait parameters(percentage of support time,stride,pace),knee function(HSS score),quality of life(AIMS2 score)were observed.Results Com-pared with control group,the amount of intraoperative and postoperative blood loss and drainage volume 2 days after operation were less in the study group,and the operation time and hospital stay were shorter(P<0.05).The deviations of LTC Angle,FFC Angle,HKA Angle,LFC Angle and FTC Angle in the study group were smaller than those in the control group(P<0.05).At 3 months,6 months and 12 months after surgery,the percentage of knee ROM,supporting time,stride length and walking speed of the research group were higher than those of the control group,while the coronal-position mLDFA and HKA were lower than those of the control group(P<0.05).The proportion of WBC and PMN in joint fluid at 3 months,6 months and 12 months after surgery was lower than that in control group(P<0.05).The HSS score of the study group was higher than that of the control group at 3 months,6 months and 12 months after operation,and the AIMS2 score was lower than that of the control group(P<0.05).There was no statistically significant difference in the incidence of complications between the study group and the control group(P>0.05).Conclusion The new improved 3D PSI-assisted TKA treatment of KOA can optimize the surgical situation,improve operating accuracy,improve the patient's lower limb alignment,promote limb function recovery,help improve the quality of life,and has high safety.
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ObjectiveTo explore the scientific connotation of fried charcoal survivability of Lonicerae Japonicae Flos（LJF） by analyzing the correlation between the color change and the intrinsic components during the processing of LJF Carbonisata（LJFC）， and taking pH， charcoal adsorption and microscopic characteristics as indexes. MethodLJFC samples with different degrees of processing were prepared according to the stir-frying time of 0.0， 1.5， 3.0， 4.5， 6.0， 7.5， 9.0， 10.5 min（numbered S1-S8）， and the contents of gallic acid， chlorogenic acid， cryptochlorogenic acid， rutin， luteoloside， isochlorogenic acid A and isochlorogenic acid C were determined by high performance liquid chromatography（HPLC）， and the L*（brightness）， a*（red-greenness） and b*（yellow-blueness） of LJFC samples with different degrees of processing were determined by spectrophotometer， and the correlation analysis and principal component analysis（PCA） between the contents of seven representative components and the color of the samples were carried out by SPSS 26. 0 and SIMCA-P 14.1. Then pH， adsorption force and characteristic structure of different samples of LJFC were detected and the processing pattern of LJFC was analyzed. ResultThe results of quantitative analysis revealed that the contents of luteoloside， rutin， chlorogenic acid and isochlorogenic acid A gradually decreased， and the contents of cryptochlorogenic acid， isochlorogenic acid C and gallic acid firstly increased and then decreased. The L* and b* of the sample powders decreased， and a* showed a trend of increasing and then decreasing. The L* and b* were positively correlated with the contents of chlorogenic acid， rutin， luteoloside， isochlorogenic acid A， b* was positively correlated with the content of gallic acid， and a* was positively correlated with the contents of cryptochlorogenic acid and isochlorogenic acid C. PCA revealed that samples could be clearly divided into 3 groups， S1-S2 as one group， S3-S5 as one group， and S6-S8 as one group， with S3 having the highest score. The results of regression analysis showed that only isochlorogenic acid C could be used to predict the contents of components by colorimetric values combined with regression equations. Physicochemical analysis showed that pH of LJFC increased with the increase of degree of charcoal stir-frying， while adsorption force showed a tendency of increasing and then decreasing， with the highest adsorption force in the S5 sample， and the non-glandular hairs， calcium oxalate clusters and pollen grains had a varying degree of decreasing with the deepening of processing degree， and the microstructures of S6-S8 samples were obviously charred with pollen grains almost invisible. ConclusionThe changes in chemical composition and color characteristics of LJFC during the processing have certain correlations， combined with the changes in physicochemical properties， S5 sample is found to be the optimal processed products， which can provide a reference for the processing standardization and quality evaluation of LJFC， and enrich the scientific connotation of fried charcoal survivability of LJF.
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ObjectiveThe advent of atomic force microscope (AFM) provides a powerful tool for the studies of life sciences. Particularly, AFM-based indentation assay has become an important method for the detection of cellular mechanics, yielding numerous novel insights into the physiological and pathological activities from the single-cell level and considerably complementing traditional biochemical ensemble-averaged assays. However, current AFM indentation technology is mainly dependent on manual operation with low efficiency, seriously restricting its practical applications in the field of life sciences. Here, a method based on the combination of deep learning image recognition and AFM is developed for precisely and efficiently detecting the mechanical properties of single isolated cells and clustered cells. MethodsThe YOLO deep learning algorithm was used to recognize the central region of the cell in the optical image, the dual UNet neural network with an embedded vision transformer (ViT) module was used to recognize the peripheral regions of cell, and the template matching algorithm was used to recognize the tip of spherical probe. Based on the automatic determination of the positional relationships between the microsphere tip and the different parts of cell, the AFM tip was accurately moved to the central and peripheral regions of the target cell for rapid measurements of cell mechanical properties. Two types of cells, including HEK 293 cell (human embryonic kidney cell) and HGC-27 cell (human undifferentiated gastric cancer cell), were used for the experiments. The Hertz model was applied to analyze the force curves obtained on cells to obtain cellular Young’s modulus. ResultsAFM probe can be precisely moved to the different parts (central areas and peripheral areas) of cells to perform mechanical measurements under the guidance of deep learning-based optical image automatic recognition. The experimental results show that the proposed method is not only suitable for single isolated cells, but also suitable for clustered cells. ConclusionThe research demonstrates the great potential of deep learning image recognition to aid AFM in the precise and efficient detection of cellular mechanical properties mechanics, and combining deep learning-based image recognition with AFM will benefit the development of high-throughput AFM-based methodology to measure the mechanical properties of cells.
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Objective: Eye drops may contain certain preservatives, and there is concern in patients who use them on a daily basis for the treatment of diseases, including corneal epithelial disorder and glaucoma. PF eye drops (Rohto Nitten Co., Ltd.) are used widely; however, their usability may be difficult in patients prescribed these medications for the first time. Therefore, fact-finding was performed on the usability of PF eye drops, particularly the difficulty in squeezing out these eye drops. Methods: The squeezing forces for various eye drops in 11 different shapes were determined. A sensuality evaluation examination on “the easiness of pushing out the eye drops” was performed in addition to a questionnaire survey targeting patients who used eye drops at a community pharmacy. Results: The squeezing forces ranged from 2.0 to 17.1 N. This study showed that the squeezing force tended to increase as the drop got closer to the opening of the container. Significant differences in the sensuality examination scores were found: 3.09 points for Santen Pharmaceutical Co., Ltd.; 3.07 points for Senju Pharmaceutical Co., Ltd.; 2.47 points for Sawai Pharmaceutical Co., Ltd.; and 1.37 points for PF eye drops for any place other than Santen and Senju (p<0.001). Conclusion: When eye drops were prescribed for an elderly individual, the pharmacist considered it necessary to suggest an alternative agent to the doctor depending on body function. In addition, it is important to explain to the patient that an additional squeezing force is required to push out the drop as it gets closer to the opening of the container.
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BACKGROUND:In response to the limitations of traditional repair methods for bone defects,stem cells are widely used in the research of regenerative medicine.Chemical factors are the current research hotspots,but recent studies confirm that the application of physical factors to regulate stem cell differentiation at home and abroad has been intensifying,and physical factors combined with biological scaffolds in bone tissue engineering provide a new idea and method for solving the difficult problem of bone defect repair,with good development prospects. OBJECTIVE:To summarize the molecular mechanisms of physical factors such as electromagnetic fields and ultrasound on osteogenic differentiation of stem cells as well as the regulation of signaling pathways and the feasibility of their application in bone tissue engineering. METHODS:A computerized search of the CNKI and PubMed for the last 20 years was conducted.In the title and abstract,we used"stem cell,bone defect,osteogenic differentiation,electromagnetic fields,ultrasound,shock wave,low-level laser therapy,mechanical force,bone tissue engineering"in Chinese and"stem cell,osteoporosis,osteogenic differentiation,electromagnetic fields,ultrasound,bone tissue engineering"in English as search terms.A total of 94 relevant articles were included for review. RESULTS AND CONCLUSION:(1)As a non-invasive,non-contact adjuvant therapy,physical factors have a significant impact on bone tissue engineering,and have a positive effect on regulating osteogenic differentiation of stem cells,promoting cell proliferation and viability in bone engineering scaffolds.(2)In addition to activating signaling pathways and osteogenic gene transcription,physical factors can also improve vascularization,increase the volume,area and thickness of bone formed in the stent,promote osseointegration,and improve the success rate of bone scaffolds in regenerating healthy bone tissue.(3)However,the use of physical factors for bone tissue engineering uses different experimental conditions,such as scaffold type,cell type,and intervention conditions,and cannot be directly compared to determine the best parameter settings.There is also a lack of consistency in the effectiveness of these different interventions in promoting fracture healing in clinical use.Therefore,it is necessary to further determine the optimal parameters of physical factors for bone tissue engineering in the future.(4)In general,as an ideal adjuvant therapy,physical factors have great potential in combining with various biomaterials and applying them in bone tissue engineering.
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BACKGROUND:Bone is a remarkable natural material possessing piezoelectric properties.By harnessing the biomimetic piezoelectric effect,tissue engineering materials can be employed to effectively address bone tissue defects and facilitate their repair. OBJECTIVE:Using a solid-phase force chemistry technique,a piezoelectric scaffold with inherent osteogenic properties was meticulously fabricated.This unique scaffold was then assessed for its impact on osteoblast adhesion,proliferation,and osteogenic differentiation. METHODS:Polyvinylidene fluoride(PVDF)powders,along with commercially available NaCl(mass ratios are 60:40,50:50,40:60,and 30:70,respectively),were subjected to solid-phase shear milling technology,resulting in a homogenous mixture.Through a melting process,a substantial material was formed,and subsequent treatment with a pure water solution effectively eliminated the NaCl.Consequently,PVDF piezoelectric foam scaffolds with varying pore sizes were successfully prepared.These materials were categorized as PVDF-40,PVDF-50,PVDF-60,and PVDF-70,denoting the respective mass percentages of NaCl during preparation.The surface morphology,crystal phase composition,thermodynamic behavior,mechanical properties,and piezoelectric properties of each group were meticulously characterized.The four kinds of piezoelectric foam scaffolds were co-cultured with the MG63 osteoblast cell line to evaluate its biocompatibility and potential to promote bone differentiation. RESULTS AND CONCLUSION:(1)The scanning electron microscopy,four groups of scaffolds had multi-level pores.As the NaCl mass fraction in the mixed powder increased,the porosity of the scaffolds increased.X-ray energy dispersion spectrum,X-ray diffraction,Fourier transform infrared spectroscopy,and thermogravimetric analysis collectively revealed the scaffold predominantly comprised the α phase,which inherently lacked piezoelectric properties.However,the application of solid-phase force chemistry successfully stimulated the formation of the β phase,thereby enhancing the scaffold's piezoelectric properties.Notably,the PVDF-60 group exhibited the highest proportion of the β phase among all the tested groups.The results of cyclic compression testing and piezoelectric performance assessment demonstrated that the PVDF-60 group exhibited superior compressive strength and piezoelectric performance compared to the other groups.(2)The findings from scanning electron microscopy and laser confocal microscopy exhibited that MG63 cells adhered well to the surface of the four groups of scaffolds,with good morphology,extended more pseudopods,and secreted a large amount of extracellular matrix.CCK-8 assay revealed that the proliferative absorbance of PVDF-60 cells cultured for 4 days was higher than that of the other three groups(P<0.000 1).Alkaline phosphatase staining and alizarin red staining showed that the expression of alkaline phosphatase and the number of calcified nodules in the PVDF-60 group were higher than those in the other three groups(P<0.01,P<0.000 1).(3)The piezoelectric PVDF foam-based scaffolds demonstrated favorable cytocompatibility.Notably,the PVDF-60 group showed superior mechanical properties,piezoelectric performance,and bone-inducing capabilities.
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BACKGROUND:Human plantar pressure can reflect the health status of the lower limbs and even the whole body,which is an important basis for gait analysis,and body mass index is an important influencing factor. OBJECTIVE:To investigate the effect of body mass index on plantar pressure. METHODS:Twenty young college students from Xuzhou Medical University,including 10 males and 10 females aged 19-21 years,were selected as test subjects and divided into three groups according to the body mass index value:overweight group(body mass index>25 kg/m2,n=3),lean group(body mass index<18 kg/m2,n=4),and normal group(body mass index 18-25 kg/m2,n=13).A natural walking gait test was carried out on the three groups of subjects with a Zebris pressure distribution measurement plate to obtain the complete gait cycle parameters.The time proportion of support time phase,peak pressure,time to peak force,peak force and impulse volume were analyzed and the correlation between each parameter and the body mass index was analyzed by Person analysis. RESULTS AND CONCLUSION:(1)Compared with the other two groups,the time proportion of support time phase of subjects in the overweight group was relatively small,while the time proportion in the foot heel contact period and forefoot extension period was relatively large.There was a positive correlation of the time proportion of the foot heel contact period and forefoot extension period with body mass index,while there was a negative correlation between the time proportion of the arch support period and body mass index.(2)The peak pressure of the left arch and palm of the foot of the subjects of the overweight group was higher than that of the normal group,and the peak pressure of the left and right palm of the foot of the lean group was lower than that of the normal group.The peak pressure was positively correlated with the body mass index during the foot heel contact period.There was a significant positive correlation between the peak pressure of the left foot and body mass index during the arch support period as well as the peak pressure of both feet and body mass index during the forefoot extension period.(3)Plantar peak force time in the order of the gait cycle in increasing order:heel<arch<metatarsal<toe.In the foot heel contact period,the time of peak force was negatively correlated with body mass index,but they were positively correlated with each other in the forefoot extension period.In the arch support period,the time of peak force of the left arch was significantly positively correlated with body mass index.(4)Plantar peak force was mainly expressed as medial heel>toe/middle 2-4 metatarsal>lateral heel>medial and lateral metatarsal>arch;medial heel peak force was the largest,and the arch peak force was the smallest.Except for the toe of the left foot,there was a significant positive correlation between peak force and body mass index.(5)The maximum ground impulse of the lean group and the overweight group was in the foot heel contact stage,the minimum ground impulse was in the forefoot extension period,and the minimum ground impulse of the arch was in the normal group.There was a significant positive correlation between ground impulse and body mass index at different periods.(6)The results show that young people should control their body mass index,wear appropriate shoes,protect their feet and ankles,and prevent the occurrence of flat feet.
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BACKGROUND:Pressing massage applied to myofascial trigger points(MTrPs)has shown clear effect in relieving pain.However,further research is needed to investigate the effects of different levels of pressure applied during the massage. OBJECTIVE:To investigate the different strength of pressing on MTrPs in rats with chronic pain. METHODS:Sixty SPF-rated male Sprague-Dawley rats were randomly divided into a blank group of 10 rats not involved in MTrPs modeling and 50 rats involved in modeling.The MTrPs model was established in the left medial thigh muscle of rats by blunt strikes combined with centrifugal exercise and 40 rats that met the evaluation criteria after modeling were randomly divided into model group,light press group,medium press group and heavy press group,with 10 rats in each group.The rats in the blank group and the model group were not intervened,while the rats in the light press group,the medium press group and the heavy press group were intervened with a homemade press stimulator with light force(0.3 kg),medium force(0.5 kg)and heavy force(0.7 kg)to MTrPs.The intervention time was 7.5 minutes per session,with one session every other day,totaling seven sessions.Electromyogram,soft tissue tension and mechanical pain threshold were detected by electrophysiological instruments,soft tissue tension tester,and pressure painmeter,respectively.After the intervention,in the blank group,muscle tissue was taken from the inside of the left thigh,while in the other groups,MTrPs tissue was taken.The pathological morphology was observed by hematoxylin-eosin staining,while enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of cyclooxygenase-2,prostaglandin E2 and bradykinin. RESULTS AND CONCLUSION:Compared with the blank group,the model group had lower mechanical pain thresholds,higher soft tissue tone,higher amplitude frequency of spontaneous electrical activity,significant pathomorphological changes,and increased levels of cyclooxygenase-2,prostaglandin E2 and bradykinin(P<0.05).Compared with the model group,the medium press group and the heavy press group showed increased mechanical pain thresholds,decreased soft tissue tension,decreased spontaneous potential frequency amplitude,and decreased levels of cyclooxygenase-2,prostaglandin E2 and bradykinin(P<0.05),and significant recovery on pathomorphological changes.No significant changes in the above indicators were observed in the light press group(P>0.05).Compared with the medium press group,the heavy press group showed better improvement in the above indicators(P<0.05).To conclude,moderate to heavy pressing is often required to alleviate MTrPs pain.
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OBJECTIVE:The effect of post-activation potentiation on sports performance is characterized by increased muscle mobility and increased rate of muscle force generation.In this paper,Meta-analysis is used to quantitatively evaluate the effects of post-activation potentiation on sprint speed,jumping performance,and kinetic parameters(peak impulse,peak power,maximum ground reaction force,rate of force generation,etc.)after activation of relative strength levels in the lower limbs. METHODS:Electronic databases such as CNKI,WanFang,Web of Science,PubMed,and Medline were retrieved for randomized control,random crossover,or clear grouping according to the relative strength levels of the lower limbs(non-randomized controls)on the post-activation potentiation effect after activation induced by the relative strength level of the lower limbs.Free weight equipment and rapid telescopic compound exercises were used as main intervention methods in each group.The publication time of the literature was from the inception of each database until August 5,2023.Endnote software was used to manage the literature.Literature quality assessment was conducted using the PEDro scale for randomized controlled trials and ROBINS-I 2.0 standards for non-randomized controlled trials.Revman5.4 and Stata15.0 software were used to conduct publication bias evaluation,subgroup analysis and sensitivity analysis of the extracted data,and forest plots were produced for Meta-analysis. RESULTS:Eleven documents(seven randomized controlled trials and four non-randomized controlled trials)were finally included,including 216 subjects.Overall,the methodological quality of the literature was high.According to the grouping standard of 1-repetition maximum/body mass>2 for the strong group and 1-repetition maximum/body mass≤2 for the normal group,there were 99 subjects in the strong group and 117 subjects in the normal group,all of whom were male.The positive effect of post-activation potentiation on sprint performance in the strong group was significantly higher than that in the normal group[standardized mean difference(SMD)=-1.34,95%confidence interval(CI):-1.74 to-0.93,P<0.000 01];the positive effect of post-activation potentiation on vertical jump height showed no significant difference between the strong and normal group(SMD=0.30,95%CI:-0.07 to 0.66,P=0.11);the positive effect of post-activation potentiation showed no significant difference between the strong and normal groups in terms of peak impulse(SMD=-0.07,95%CI:-0.62 to 0.47,P=0.61],peak power(SMD=0.21,95%CI:-0.29 to 0.72,P=0.12),maximum ground reaction force(SMD=0.31,95%CI:-0.20 to 0.81,P=0.16)and force generation rate(SMD=0.36,95%CI:-0.11 to 0.82,P=0.39). CONCLUSION:The post-activation potentiation effect in the strong group can significantly increase the short-distance sprint speed.The potentiation effect after activation of the relative strength level of the lower limbs has similar effects on the kinematic and kinetic parameters,including explosive vertical jump height,peak impulse,peak power,maximum ground reaction force and force generation rate.
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BACKGROUND:The maximum muscle strength is typically used for evaluating the recovery of muscle function after anterior cruciate ligament reconstruction.Recent studies have suggested that neuromuscular function should also be considered,such as rate of force development,which measures the slope of the force time curve at different time intervals under conditions of isometric muscle contraction. OBJECTIVE:To elaborate on the current research status and shortcomings of muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction surgery,and analyze the degree of defects in quadriceps femoris and hamstring isometric rate of force development at different times after surgery;to analyze the effect of isometric rate of force development on postoperative functional performance,thereby providing important information for optimizing postoperative rehabilitation following anterior cruciate ligament reconstruction,reducing secondary injury to patients,and reducing the incidence of knee osteoarthritis. METHODS:Literature retrieval of CNKI,VIP,WanFang and PubMed was performed using"anterior cruciate ligament,rate of force development"as Chinese search terms and"anterior cruciate ligament,rate of force development,rate of torque development"as English search terms.Finally,69 articles were included according to inclusion and exclusion criteria. RESULTS AND CONCLUSION:Most studies have found defects in bilateral muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction within 6 months.Early isometric rate of force development of the bilateral hamstring muscles(i.e.the slope of the force time curve at any time interval during muscle contraction of 100 ms)showed significant improvement after 6 months.However,long-term defects in early isometric rate of force development of the bilateral quadriceps indicate long-term damage to the neuromuscular function of the quadriceps after surgery.There is limited research on late isometric rate of force development(the slope of the force time curve at any time interval after 100 ms of muscle contraction),and conclusions cannot be drawn.Regarding landing exercises(jumping to the ground,lateral cutting,etc.)and daily activities(walking,running),early isometric rate of force development of the quadriceps is more correlated with isometric peak torque.Abnormal biomechanical changes during exercise are considered an important risk factor for secondary injury and traumatic knee osteoarthritis in patients.Actively improving early isometric rate of force development of the quadriceps may reduce the incidence of secondary injury and traumatic knee osteoarthritis.Currently,there is limited evidence to suggest that whole-body vibration training can improve early isometric rate of force development of the quadriceps femoris in patients undergoing anterior cruciate ligament reconstruction.It is recommended to use neuromuscular electrical stimulation to intervene in the quadriceps and hamstring in the early postoperative stage and implement explosive force and high resistance training in the late postoperative stage,which may improve the isometric rate of force development in patients.Generating sufficient muscle strength in a short period of time is necessary to effectively protect the anterior cruciate ligament,while the relationship between isometric rate of force development in the hamstring muscle and functional performance is still unclear,which may provide information on preventing secondary injury in patients.It is recommended to use the isometric rate of force development as one of the evaluation indicators for guiding rehabilitation and restoring movement.In addition to focusing on improving symmetry and differences from normal individuals,the hamstring to quadriceps strength ratio should also be considered.An appropriate range of ratios can ensure the balance of muscles during rapid muscle exertion,which may reduce the occurrence of secondary injuries.However,the normal range of ratios is not yet clear.Future research should consider the effects of graft type and knee flexion angle on isometric rate of force development,in order to identify neuromuscular dysfunction in patients as much as possible and help them recover better.
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BACKGROUND:The abnormal gait of stroke patients seriously affects their propulsive force during walking,which subsequently reduces their walking speed,walking distance,and stability,increases their risk of falls,and seriously affects their quality of life. OBJECTIVE:To review the relevant research on propulsive force deficits in stroke patients with hemiplegia,to summarize the understanding of existing researchers on propulsive force deficits,to analyze the relationship between propulsive force and gait,and finally to explain and compare the latest rehabilitation technologies used to improve propulsive force deficits,providing reference for clinical treatment. METHODS:Relevant literature was retrieved from WanFang,CNKI,PubMed,and Web of Science Core Collection through computer search.The Chinese and English search terms were"propulsive force OR propulsive,stroke OR cerebral infarction OR hemiplegia,walk* OR gait."The search time limit was from 2003 to 2023,and 71 articles were finally included for review and analysis. RESULTS AND CONCLUSION:Training targeting the hip and ankle joints may be more effective for patients'walking function,especially training with the application of flexible exoskeleton robots,but more sufficient evidence is still needed to use propulsion as a prognostic indicator of walking function in stroke patients.Biomechanical variables related to propulsive force include:the hip joint extension angle at terminal stance,ankle joint dorsiflexion torque,and knee joint extension.Damage to the corticospinal tract,cerebellar-cortical pathways,and the reticulospinal tract in hemiplegic patients are associated with reduced propulsive force and gait asymmetry.Propulsive force is crucial for the stability of healthy gait,and a decrease in propulsive force is unfavorable for gait stability.Gait symmetry is correlated with propulsive force,stride length symmetry,trunk displacement,and lower limb swing ability,with propulsive force being a key factor.Propulsive force can serve as a quantitative indicator for assessing the gait of hemiplegic patients,and evaluation of gait using propulsive force is beneficial for the long-term development of walking ability.Main rehabilitation techniques for improving propulsive force include:lower limb exoskeleton robot walking training,treadmill training combined with functional electrical stimulation,adaptive speed treadmill training,biofeedback technology,and whole-body vibration training.Among them,whole-body vibration training and biofeedback technology are more effective.The specific contributions and mechanisms of the hip,knee,and ankle joints in improving propulsive force are still controversial,but it is expected that the contributions of the hip and ankle joints are greater.Focusing on the improvement of propulsive force as a rehabilitation goal may yield more sustainable advancements in walking function.However,several current challenges persist in this field:understanding the neurobiological basis of propulsive force deficits in stroke patients,assessing the long-term efficacy of current rehabilitation techniques for enhancing propulsive force,and determining the most suitable patient populations for the application of major rehabilitation techniques aiming at improving propulsive force.These areas require further exploration by subsequent researchers.