Shell Modulation of Hollow Metal Sulfide Nanocomposite for Stable Potassium Storage at Room and High Temperature.

The large size of K-ion makes the pursuit of stable high-capacity anodes for K-ion batteries (KIBs) a formidable challenge, particularly for high temperature KIBs as the electrode instability becomes more aggravated with temperature climbing. Herein, we demonstrate that a hollow ZnS@C nanocomposite (h-ZnS@C) with a precise shell modulation can resist electrode disintegration to enable stable high-capacity potassium storage at room and high temperature. Based on a model electrode, we identify an interesting structure-function correlation of the h-ZnS@C: with an increase in the shell thickness, the cyclability increases while the rate and capacity decrease, shedding light on the design of high-performance h-ZnS@C anodes via engineering the shell thickness. Typically, the h-ZnS@C anode with a shell thickness of 60 nm can deliver an impressive comprehensive performance at room temperature; the h-ZnS@C with shell thickness increasing to 75 nm can achieve an extraordinary stability (88.6 % capacity retention over 450 cycles) with a high capacity (450 mAh g-1) and a superb rate even at an extreme temperature of 60 °C, which is much superior than those reported anodes. This contribution envisions new perspectives on rational design of functional metal sulfides composite toward high-performance KIBs with insights into the significant structure-function correlation.

Facile Fabrication of Hollow Nanoporous Carbon Architectures by Controlling MOF Crystalline Inhomogeneity for Ultra-Stable Na-Ion Storage.

Hollow nanoporous carbon architectures (HNCs) present significant utilitarian value for a wide variety of applications. Facile and efficient preparation of HNCs has long been pursued but still remains challenging. Herein, we for the first time demonstrate that single-component metal-organic frameworks (MOFs) crystals, rather than the widely reported hybrid ones which necessitate tedious operations for preparation, could enable the facile and versatile syntheses of functional HNCs. By controlling the growth kinetics, the MOFs crystals (STU-1) are readily engineered into different shapes with designated styles of crystalline inhomogeneity. A subsequent one-step pyrolysis of these MOFs with intraparticle difference can induce a simultaneous self-hollowing and carbonization process, thereby producing various functional HNCs including yolk-shell polyhedrons, hollow microspheres, mesoporous architectures, and superstructures. Superior to the existing methods, this synthetic strategy relies only on the complex nature of single-component MOFs crystals without involving tedious operations like coating, etching, or ligand exchange, making it convenient, efficient, and easy to scale up. An ultra-stable Na-ion battery anode is demonstrated by the HNCs with extraordinary cyclability (93 % capacity retention over 8000 cycles), highlighting a high level of functionality of the HNCs.

Multiple Accessible Redox-Active Sites in a Robust Covalent Organic Framework for High-Performance Potassium Storage.

Covalent organic framework (COF) materials with porous character and robust structure have significant applied implications for K-ion battery (KIB) anodes, but they are limited by the low reversible capacity and inferior rate capability. Here, based on theoretical calculations, we identified that a porous bulk COF featuring numerous pyrazines and carbonyls in the π-conjugated periodic skeleton could provide multiple accessible redox-active sites for high-performance potassium storage. Its porous structure with a surface-dominated storage mechanism enabled the fast and stable storage of K-ions. Its insolubility in organic electrolytes and small volumetric change after potassiation ensured a robust electrode for stable cycling. As a KIB anode, this bulk COF demonstrated an unprecedentedly outstanding combination of reversible capacity (423 mAh g-1 at 0.1 C), rate capability (185 mAh g-1 at 10 C), and cyclability. The theoretical simulation and comprehensive characterizations confirmed the active sites are contributed by C═O, C═N, and the cation-π effect.

Design, synthesis and identification of N, N-dibenzylcinnamamide (DBC) derivatives as novel ligands for α-synuclein fibrils by SPR evaluation system.

PET imaging of α-synuclein (α-syn) deposition in the brain will be an effective tool for earlier diagnosis of Parkinson's disease (PD) due to α-syn aggregation is the widely accepted biomarker for PD. However, the necessary PET radiotracer for imaging is clinically unavailable until now. The lead compound discovery is the first key step for the study. Herein, we initially established an efficient biologically evaluation system well in highthroughput based on SPR technology, and identified a novel class of N, N-dibenzylcinnamamide (DBC) compounds as α-syn ligands through the assay. These compounds were proved to have high affinities against α-syn aggregates (KD < 10 nM), which well met the requirement of binding activity for the PET probe. These DBC compounds were firstly reported as α-syn ligands herein and the preliminary obtained structure has been further modified into F-labeled ones. Among them, a high-affinity tracer (5-41) with 1.03 nM (KD) has been acquired, indicating its potential as a new lead compound for developing PET radiotracer.

Separation and identification of process-related substances and degradation products in mycophenolate mofetil by liquid chromatography coupled with quadrupole-time of flight mass spectrometry.

Mycophenolate mofetil is an antiproliferative immunosuppressive agent. Since its clinical efficacy and safety highly depend on the quality, the stability, and impurity profiles of mycophenolate mofetil are paid ever-increasing attention. However, there are few published studies reporting the complete characterization of both the process-related substances and degradation products in mycophenolate mofetil. In the present study, a highly specific and efficient liquid chromatography coupled with quadrupole-time of flight mass spectrometry method was developed for the separation and identification of all the potential impurities in mycophenolate mofetil. According to the ICH Q1A (R2) guideline, the forced degradation studies were conducted to elucidate the stability and degradation pathways of mycophenolate mofetil. A total of 15 related substances, including the process-related substances and stress degradation products were characterized by the established hyphenated method, 11 of them have not been reported before. In view of the synthetic route and degradation pathways of mycophenolate mofetil, the origins and formation mechanisms of these related substances were discussed. Based on the obtained stability and impurity profiles, key points of the manufacturing process were proposed to deliver mycophenolate mofetil with high purity.

[Independent external verification of the nomograms for predicting lymph node metastasis in penile cancer].

Objective: To evaluate the two newly established nomograms for predicting lymph node metastasis in penile cancer based on the clinical data on a large cohort of patients. METHODS: We retrospectively studied the clinical data on 93 patients with penile cancer treated in the Center for Tumor Prevention and Treatment. Using the two recently established nomograms (Bhagat nomogram and Zhu nomogram), we predicted lymph node metastasis in the patients, analyzed the differences between prediction and the results of postoperative pathology, and compared the accuracy of prediction between the two nomograms with the receiver operating characteristic (ROC) curve and the area under the curve (AUC). RESULTS: The median age of the patients was 55 (27－82) years. Positive lymph nodes were found in 31 cases (33.3%) postoperatively and in 9 (21.9%) of the 41 clinically negative cases. The AUC of the Bhagat nomogram was 0.739 and that of Zhu nomogram was 0.808, both of which were similar to the prediction accuracy of internal verification and manifested a medium predictive ability. CONCLUSIONS: The newly established Bhagat and Zhu nomograms can be used for predicting lymph node metastasis in penile cancer, but with a low precision, and therefore cannot be relied exclusively for the option of inguinal lymphadenectomy.

Alterations and correlations of the gut microbiome, metabolism and immunity in patients with primary biliary cirrhosis.

We selected 42 early-stage primary biliary cirrhosis (PBC) patients and 30 healthy controls (HC). Metagenomic sequencing of the 16S rRNA gene was used to characterize the fecal microbiome. UPLC-MS/MS assaying of small molecules was used to characterize the metabolomes of the serum, urine and feces. Liquid chip assaying of serum cytokines was used to characterize the immune profiles. The gut of PBC patients were depleted of some potentially beneficial bacteria, such as Acidobacteria, Lachnobacterium sp., Bacteroides eggerthii and Ruminococcus bromii, but were enriched in some bacterial taxa containing opportunistic pathogens, such as γ-Proteobacteria, Enterobacteriaceae, Neisseriaceae, Spirochaetaceae, Veillonella, Streptococcus, Klebsiella, Actinobacillus pleuropneumoniae, Anaeroglobus geminatus, Enterobacter asburiae, Haemophilus parainfluenzae, Megasphaera micronuciformis and Paraprevotella clara. Several altered gut bacterial taxa exhibited potential interactions with PBC through their associations with altered metabolism, immunity and liver function indicators, such as those of Klebsiella with IL-2A and Neisseriaceae with urinary indoleacrylate. Many gut bacteria, such as some members of Bacteroides, were altered in their associations with the immunity and metabolism of PBC patients, although their relative abundances were unchanged. Consequently, the gut microbiome is altered and may be critical for the onset or development of PBC by interacting with metabolism and immunity.

HipH Catalyzes the Hydroxylation of 4-Hydroxyisophthalate to Protocatechuate in 2,4-Xylenol Catabolism by Pseudomonas putida NCIMB 9866.

In addition to growing on p-cresol, Pseudomonas putida NCIMB 9866 is the only reported strain capable of aerobically growing on 2,4-xylenol, which is listed as a priority pollutant by the U.S. Environmental Protection Agency. Several enzymes involved in the oxidation of the para-methyl group, as well as the corresponding genes, have previously been reported. The enzyme catalyzing oxidation of the catabolic intermediate 4-hydroxyisophthalate to the ring cleavage substrate protocatechuate was also purified from strain NCIMB 9866, but its genetic determinant is still unavailable. In this study, the gene hipH, encoding 4-hydroxyisophthalate hydroxylase, from strain NCIMB 9866 was cloned by transposon mutagenesis. Purified recombinant HipH-His6 was found to be a dimer protein with a molecular mass of approximately 110 kDa. HipH-His6 catalyzed the hydroxylation of 4-hydroxyisophthalate to protocatechuate with a specific activity of 1.54 U mg(-1) and showed apparent Km values of 11.40 ± 3.05 µM for 4-hydroxyisophthalate with NADPH and 11.23 ± 2.43 µM with NADH and similar Km values for NADPH and NADH (64.31 ± 13.16 and 72.76 ± 12.06 µM, respectively). The identity of protocatechuate generated from 4-hydroxyisophthalate hydroxylation by HipH-His6 has also been confirmed by high-performance liquid chromatography and mass spectrometry. Gene transcriptional analysis, gene knockout, and complementation indicated that hipH is essential for 2,4-xylenol catabolism but not for p-cresol catabolism in this strain. This fills a gap in our understanding of the gene that encodes a critical step in 2,4-xylenol catabolism and also provides another example of biochemical and genetic diversity of microbial catabolism of structurally similar compounds.

The catabolism of 2,4-xylenol and p-cresol share the enzymes for the oxidation of para-methyl group in Pseudomonas putida NCIMB 9866.

Pseudomonas putida NCIMB 9866 utilizes p-cresol or 2,4-xylenol as a sole carbon and energy source. Enzymes catalyzing the oxidation of the para-methyl group of p-cresol have been studied in detail. However, those responsible for the oxidation of the para-methyl group in 2,4-xylenol catabolism are still not reported. In this study, real-time quantitative PCR analysis indicated pchC- and pchF-encoded p-cresol methylhydroxylase (PCMH) and pchA-encoded p-hydroxybenzaldehyde dehydrogenase (PHBDD) in p-cresol catabolism were also likely involved in the catabolism of 2,4-xylenol. Enzyme activity assays and intermediate identification indicated that the PCMH and PHBDD catalyzed the oxidations of 2,4-xylenol to 4-hydroxy-3-methylbenzaldehyde and 4-hydroxy-3-methylbenzaldehyde to 4-hydroxy-3-methylbenzoic acid, respectively. Furthermore, the PCMH-encoding gene pchF was found to be necessary for the catabolism of 2,4-xylenol, whereas the PHBDD-encoding gene pchA was not essential for the catabolism by gene knockout and complementation. Analyses of the maximum specific growth rate (µ m) and specific activity of the gene-knockout strain to different intermediates revealed the presence of other enzyme(s) with PHBDD activity in strain 9866. However, PHBDD played a major role in the catabolism of 2,4-xylenol in contrast to the other enzyme(s).

Unveiling per- and polyfluoroalkyl substance contamination in Chinese paper products and assessing their exposure risk.

The contamination characteristics, migration patterns and health risks of per- and polyfluoroalkyl substances (PFAS) were investigated in 66 Chinese paper products by using target and non-target screening methods. Among 57 target PFASs, 5 and 6 PFASs were found in the hygiene paper products (

Expression of SOCSs in human prostate cancer and their association in prognosis.

Suppressors of cytokine signaling (SOCS) proteins have been identified as negative feedback regulators of cytokine-mediated signaling in various tissues, and demonstrated to play critical roles in tumorigenesis and tumor development of different cancers. The involvement of SOCSs in human prostate cancer (PCa) has not been fully elucidated. Thus, the aim of this study is to investigate the expression patterns and the clinical significance of SOCSs in PCa. The expression changes of SOCSs at mRNA and protein levels in human PCa tissues compared with adjacent benign prostate tissues were, respectively, detected by using real-time quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) and immunohistochemistry analyses. The associations of SOCSs expression with clinicopathological features and clinical outcome of PCa patients were further statistically analyzed. Among SOCSs, both QRT-PCR and immunohistochemistry analyses found that SOCS2 expression was upregulated (at mRNA level: change ratio = 1.98, P = 0.031; at protein level: 5.12 ± 0.60 vs. 2.68 ± 0.37, P = 0.016) and SOCS6 expression was downregulated (at mRNA level: change ratio = -1.65, P = 0.008; at protein level: 3.03 ± 0.32 vs. 4.0.72 ± 0.39, P = 0.004) in PCa tissues compared with those in non-cancerous prostate tissues. In addition, the upregulation of SOCS2 in PCa tissues was correlated with the lower Gleason score (P < 0.001), the absence of metastasis (P < 0.001) and the negative PSA failure (P = 0.009); the downregulation of SOCS6 tended to be found in PCa tissues with the higher Gleason score (P = 0.016), the advanced pathological stage (P = 0.007), the positive metastasis (P = 0.020), and the positive PSA failure (P = 0.032). Furthermore, both univariate and multivariate analyses showed that the downregulation of SOCS2 was an independent predictor of shorter biochemical recurrence-free survival. Our data offer the convincing evidence for the first time that the dysregulation of SOCS2 and SOCS6 may be associated with the aggressive progression of PCa. SOCS2 may be potential markers for prognosis in PCa patients.

Down-regulation of the ErbB3 binding protein 1 in human bladder cancer promotes tumor progression and cell proliferation.

The ErbB3 binding protein 1 (Ebp1) represents a downstream effector of the ErbB signaling network and has been demonstrated to be a potent tumor suppressor in various human malignancies, however, its involvement in human bladder cancer is still unclear.To investigate the clinical significance and potential role of ErbB3 binding protein 1 (Ebp1) in bladder cancer. Ebp1 expression at protein and gene levels in 52 surgically removed bladder cancer specimens as well as 21 adjacent normal bladder specimens were respectively detected by immunohistochemistry and qRT-PCR. The association of Ebp1 protein expression with the clinicopathological features of bladder cancer was also statistically analyzed. Its roles in bladder cancer cell line were further evaluated. The expression level of Ebp1 protein and gene in bladder cancer tissues was significantly lower than that in adjacent normal bladder tissues (P < 0.01). When categorized into low vs. high expression, the down-regulation of Ebp1 protein was associated with the advanced pathologic stage (P = 0.036) and the high histologic grade (P = 0.001) of patients with bladder cancer. Moreover, following the transfection of Ebp1 in bladder cancer cells, not only cell proliferation and cell invasion decreased significantly, but also the cell cycle was blocked at G0/G1 stage. Our data suggest for the first time that the down-regulation of Ebp1 closely correlates with advanced clinicopathological characteristics of human bladder cancer. Furthermore, Ebp1 plays an important role in the bladder cancer cells' proliferation by regulating the cancer cell cycle from G0/G1 to S.

[Stenting of subtotal conclusion of internal carotid artery and comparing the cerebral embolic load of proximal balloon protection device with distal filter protection device].

OBJECTIVE: To study the safety, efficacy and perioperative complications of endovascular therapy in the treatment of subtotal conclusion of internal carotid artery(ICA) in patients. To compare the cerebral embolic load of proximal balloon protection device versus distal filter protection device during the operation. METHODS: Review all the operations of stenting for subtotal conclusion of ICA in Xuanwu hospital. New cerebral infarction after stenting was assessed by diffusion-weighted magnetic resonance imaging. Count the number of new ischemic lesions of every patient. RESULTS: 35 patients with subtotal conclusion of ICA received endovascular stenting. Proximal protective device was used for 21 patients. Distal protective device was used for 14 patients. All procedures succeeded. 32 patients received the cerebral MRI 1 week before and within 48 hours after the operation. Compared with filter protection(n = 14), proximal balloon device(n = 18) resulted in a significant reduction in the incidence of new cerebral infarction (6/18 vs 10/14, P = 0.03). The number of new cerebral ischemic lesions were significant reduced by proximal balloon device (1/18 vs 4/14, P = 0.0006) . There were no serious cardiovascular events in 35 patients during the operation and the following up 3 months. 3 patients had restenosis which was demonstrated by ultrasound of ICA at 3 months after stenting. CONCLUSIONS: Endovascular stenting may be a safe and valid method for the treatment of subtotal occlusion of ICA. For the stenting of subtotal occlusion of ICA, proximal balloon protection device as compared with filter protection may reduce the embolic load to the brain more effectively. The stenting of subtotal occlusion of ICA still needs the randomized trails to confirm the safety and validity.

[Investigation of disease spectrum in the PICU of Shengjing Hospital of China Medical University between 2005 and 2012].

OBJECTIVE: To summarize the spectrum of disease and common diseases that cause death in children admitted to the Pediatric Intensive Care Unit (PICU), Shengjing Hospital of China Medical University between 2005 and 2012. METHODS: A retrospective analysis was carried out on the clinical data of 4484 children admitted to the PICU of Shengjing Hospital between 2005 and 2012. RESULTS: Acute bronchopneumonia, which was found in 1099 (24.51%) of the 4484 cases, was the most common disease in the PICU between 2005 and 2012. The incidence of intracranial infection, sepsis, hand-foot-mouth disease and trauma showed an increasing trend from 2005 to 2012, but that of non-traumatic intracranial hemorrhage, epilepsy and congenital heart disease showed a decreasing trend. The mortality decreased from 11.5% in 2005 to 3.1% in 2012, and the overall mortality was significantly higher in 2005-2008 than in 2009-2012 (11.98% vs 4.41%; P<0.01). The main causes of death included severe acute bronchial pneumonia, severe sepsis, complex congenital heart disease, severe cerebral trauma, respiratory failure, severe hand-foot-mouth disease, acute poisoning and circulatory failure. CONCLUSIONS: Acute bronchopneumonia was the most common disease in the PICU of Shengjing Hospital between 2005 and 2012, but the spectrum of disease changed over time. The mortality showed a decreasing trend among the children in the PICU between 2005 and 2012, and the main causes of death included severe acute bronchial pneumonia and severe sepsis.

[Response of Organic Carbon Loss to Soil Erosion and Its Drivers: A Meta-analysis].

Soil erosion is the main driving force of soil organic carbon (SOC) loss and plays an important role in the global carbon cycle. It is helpful to understand the mechanism of SOC loss under soil erosion by evaluating the main driving factors of SOC loss under soil erosion and their influence degree. Therefore, based on 24 cases published in domestic and foreign journals from 2007 to 2021, this study investigated the effects of soil erosion on SOC loss in China under different climatic factors (climate types, rainfall, and rainfall intensity) and soil factors (soil types, bulk density, and aggregate size) by using Meta-analysis. The results showed that:① compared with that under no erosion disturbance, the SOC content under erosion decreased significantly (overall decreased 16.0%), showing obvious negative response characteristics. ② Under the erosion background, the negative response degree of SOC to different factors was as follows:rainfall intensity (65.0%)>mean annual rainfall (24.3%)>soil types (21.4%)>bulk density (20.2%)>aggregate size (16.5%)>climate types (9.1%). ③ Principal component analysis showed that climate was the dominant factor affecting SOC loss, and rainfall intensity was again shown to be the key factor. In this study, the characteristics and influencing factors of SOC loss under soil erosion in China were analyzed, which provided theoretical reference for the systematic understanding of the role of soil erosion in the carbon cycle.

[Effect of Human Bone Marrow Mesenchymal Stem Cells with Ectopic High OCT4 Expression on T Lymphocyte Function].

OBJECTIVE: To explore the effect of human bone marrow mesenchymal stem cells (MSCs) with ectopic high OCT4 expression on T-cell proliferation, activation and secretion in vitro. METHODS: Peripheral blood mononuclear cells were isolated from healthy children. Anti-CD3 and anti-CD28 monoclonal antibodies were used to activate T lymphocytes, which were stimulated by interleukin (IL)-2 for one week in vitro. Then MSCs with ectopic high OCT4 expression (MSC-OCT4) were co-cultured with activated T lymphocytes. After one week of co-culture, the supernatant was collected and the levels of Th1/Th2 cytokines [IL-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α and interferon (IFN)-γ] were determined by flow cytometry. The lymphocytes after one week of co-culture were collected and counted by Countstar software. After the proportions of activated/inactivated T cell subsets were determined by flow cytometry, the absolute lymphocyte counts were calculated and expressed as mean ± standard deviation. RESULTS: Compared with control T cell alone culture group, the proliferation of CD3+ T cells, CD3+CD4+ T cells, and CD3+CD8+ T cells were significantly inhibited in MSC group and MSC-OCT4 group. Compared with MSC, MSC-OCT4 could inhibit CD3+CD8+ T cell proliferation better (P =0.049), and mainly inhibited early T cell activation. Compared with control T cell alone culture group, the levels of IL-2 and INF-γ were significantly down-regulated both in MSC group and MSC-OCT4 group.After co-culture with T cells for one week, the level of IL-6 significantly increased in MSC group and MSC-OCT4 group compared with that before co-culture. Compared with control MSC group, MSC-OCT4 group had higher viable cell numbers after 1 week of co-culture (P =0.019), and could resist the inhibition of proliferation by higher concentration of mitomycin C. CONCLUSION: Both MSC and MSC-OCT4 can inhibit the proliferation and activation of IL-2-stimulated T cells in vitro. After overexpression of OCT4, MSC has better proliferation ability in vitro and can inhibit the proliferation of CD3+CD8+ T cells more effectively, which may have a better and more lasting immunosuppressive ability to regulate the balance of Th1/Th2.

Phenolic compounds and antioxidant properties of wheat fermented with Agaricus brasiliensis and Agaricus bisporus.

Solid-state fermentation with Agaricus brasiliensis and Agaricus bisporus on whole grain wheat was carried out. Phenolic compounds and antioxidant properties of fermented wheat were determined. The results showed that the maximum values of polyphenols contents in wheat fermented with A. brasiliensis and A. bisporus reached, respectively (3.16 ± 0.21) and (3.93 ± 0.23) mg GAE/g, which were 2.90 and 3.61 times of unfermented control. By employing ultra performance liquid chromatography coupled to mass spectrometry (UPLC-MS), 18 kinds of phenolic compounds were identified from fermented wheat. Compared with control, only 4-hydroxy-benzaldehyde was the same compound. It indicated that fermentation with the two fungi changed polyphenols contents and phenolic compounds composition in wheat to a great extent. Among these phenolic compounds, except for 4-hydroxy-benzaldehyde, 4-hydroxy-benzoic acid and ß-N-(γ-glutamyl)-4-formylphenylhydrazine, other 15 kinds of phenolic compounds were first identified from mushroom samples (including fruit bodies, mycelia and fermentation products). DPPH radical scavenging capacity, reducing power, ferrous ion chelating ability and inhibition of lipid peroxidation of fermented wheat were significantly stronger than control (P < 0.05).

[Finite element analysis on stress concentration improvement in patellofemoral joint by releasing lateral patellar retinaculum with stiletto needle based on the theory of Jinshugu()].

OBJECTIVE: To study mechanism of improvement of stress concentration on patellofemoral joint by stiletto needle releasing lateral patellar retinaculum guided by the theory of Jinshugu() and based on the finite element model of knee joint. and to elucidate the biomechanical mechanism of stiletto needle releasing changing patellar trajectory and reducing patellofemoral joint pressure. METHODS: CT data of knee joint from a normal male (aged 29, heighted 171 cm, weighted 58 kg) was selected. Starting with construction of three-dimensional model of knee joint by using finite element software, the finite element model of knee joint with complete tendonand bone structures were established through several steps, such as geometric reconstruction, reverse engineering, meshing, material assignment and loading analysis. The loading condition was set as 500 N load on knee joint, and the average tensile stress of quadriceps femoris tendon was about 200 N. To simulate the release of lateral patellar retinaculum by stiletto needle at 30 and 90 position of knee flexion in finite element model separately, and to compare the improvement of stress concentration of patellofemoral joint by stiletto needle intervention under different knee flexion conditions. RESULTS: The peak stress of patellofemoral joint and tibiofemoral joint decreased after stiletto needle releasing of patellofemoral lateral retinaculum compared with before intervention, which was(1) knee flexion at 30 degrees:patellar cartilage decreased by 0.498 MPa (decreased 9.06%), femoral trochlea decreased by 0.886 MPa(decreased 16.27%);(2) knee flexion at 90 degrees:patellar cartilage decreased by 0.558 MPa (decreased 8.6%), femoral trochlea decreasedby 0.607 MPa (decreased 9.94%). CONCLUSION: Releasing lateral patellofemoral retinaculum with stiletto needle could effectively alleviate the stress concentration of patellofemoral joint and reduce local stress peak value, which it is helpful to improve patellar trajectory and make stress distribution more uniform.

[Construction and simulation mechanical analysis of dynamic knee joint finite element model based on CT image].

OBJECTIVE: To construct a dynamic knee joint finite element model based on CT image data and verify the validity of the model. To provide a simulation model and basic data for biomechanical research of the knee joint by further finite element analysis. METHODS: The CT data of a healthy male knee joint was selected. With the help of Mimics 19.0 and Hypermesh 12.0 software, a high simulation finite element model of knee joint was established following steps, including geometric reconstruction, reverse engineering, meshing and material characterization. The dynamic knee flexion model was generated by determining the boundary conditions and torque loading, and the validity of themodel was confirmed. The biomechanical changes of the tibiofemoral and patellofemoral joints under different knee flexion angles were analyzed by applying the loads (500 N) to the finite element model during knee flexion. RESULTS: A finite element model of knee joint was established based on CT images and anatomical characteristics. The model included three-dimensional elements such as bone, ligament, cartilage, meniscus and patellar retinaculum. The different finite element models of knee flexion states were produced by applying different torques after establishing boundary conditions. According to equivalent conditions (knee flexion 30 degrees, quadriceps tendon under 200 N stretch), the peak stress value of patella was 2.209 MPa and the average Mises stress was 1.132 MPa; the peak stress value of femoral trochlear was 1.405 MPa and the average Mises stress was 0.936 MPa. The validity of the model was proved by the difference between the model and previous studies of 1% to 13.5%. Dynamic model loading showed that the Mises stressof tibiofemoral joint decreased with the increase of knee flexion angle, while the Mises stress of patellofemoral joint was positively correlated with knee flexion angle. The Mises stress of cartilage stress planes at different knee flexion angles was significantly different(P<0.05). CONCLUSION: The finite element model established in this study is more comprehensive and can effectively simulate the biomechanical characteristics of dynamic knee joint, which provides support for further simulation mechanics researches of the knee joint.