Research Progresses in Microstructure Designs of Flexible Pressure Sensors.

Flexible electronic technology is one of the research hotspots, and numerous wearable devices have been widely used in our daily life. As an important part of wearable devices, flexible sensors can effectively detect various stimuli related to specific environments or biological species, having a very bright development prospect. Therefore, there has been lots of studies devoted to developing high-performance flexible pressure sensors. In addition to developing a variety of materials with excellent performances, the microstructure designs of materials can also effectively improve the performances of sensors, which has brought new ideas to scientists and attracted their attention increasingly. This paper will summarize the flexible pressure sensors based on material microstructure designs in recent years. The paper will mainly discuss the processing methods and characteristics of various sensors with different microstructures, and compare the advantages, disadvantages, and application scenarios of them. At the same time, the main application fields of flexible pressure sensors based on microstructure designs will be listed, and their future development and challenges will be discussed.

[Clinical observation of homemade splint external fixation in the treatment of metacarpal fractures].

OBJECTIVE: To explore the clinical effect of manual reduction combined with homemade splint external fixation in the treatment of metacarpal fractures. METHODS: A retrospective analysis was performed in 126 patients with metacarpal fracture treated by manual reduction and homemade splint external fixation in the emergency department of our hospital from January 2018 to December 2018, including 102 male, 24 female, ranging in age from 9 to 73 year old, with an average of (33.2±14.3)years old. During the treatment, the X-ray was re-examined regularly, and the external fixation was continued or adjusted according to the X-ray situation. The X-ray showed callus growth. After the fracture was stable, the external fixation was removed to continue functional exercise. The TAM scoring standardwas used to evaluate the hand function, and the fracture healing and complications were summarized. RESULTS: Of the 126 patients, 6 patients were treated with operation because of fracture displacement during the treatment. The other 120 patients were treated with this method and all of them got bony healing. The healing time was (6.3±1.8) weeks. The follow up time ranged from 2 to 12 months, with a mean of (4.4±2.2) months. At the latest follow up, TAM score was used to evaluate the hand function:excellent in 105 cases, good in 13 cases, fair in 2 cases and poor in 0 case. Shortening deformity was found in 7 cases and angulation deformity in 3 cases. CONCLUSION: Manual reduction combined with homemade splint external fixation in the treatment of metacarpal fractures can achieve good clinical results. Homemade splint is easy to obtain materials and low cost, and it is an effective method worthy of clinical promotion.

Downregulation of dickkopf-1 enhances the proliferation and osteogenic potential of fibroblasts isolated from ankylosing spondylitis patients via the Wnt/ß-catenin signaling pathway in vitro.

BACKGROUND: Heterotopic ossification of the entheses is one of the most distinctive features in ankylosing spondylitis (AS). Fibroblasts are potential target cells for heterotopic ossification. The Wnt/ß-catenin pathway and its inhibitor dickkopf-1 (DKK-1) regulate bone formation. DKK-1 expression in human AS tissues has not been documented. OBJECTIVE: The purpose of the current study was to investigate the expression of DKK-1 in AS tissues and to elucidate its role in fibroblasts proliferation and osteogenesis in AS. METHODS: DKK-1 expression was assessed by western blotting, real time-polymerase chain reaction (RT-PCR), and immunohistochemistry analysis of hip synovial tissues obtained from AS and control patients. Fibroblasts were isolated, cultured, and transfected with lentiviral vectors for overexpressing human DKK-1 or an shRNA for silencing DKK-1. MTS [(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl) 2-(4-sulfophenyl)-2H-tetrazolium] and a 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay were used to detect AS fibroblasts proliferation after transfection. The expression levels of ß-catenin, phosphorylated ß-catenin, c-Myc, cyclin D1, and the osteogenesis markers alkaline phosphatase (ALP), osteocalcin (OCN), and Runt-related transcription factor 2 (Runx2) were then examined by western blot analysis. Alizarin red staining (ARS) was also used to observe biomineralization activity. RESULTS: DKK-1 was downregulated in hip synovial tissues from AS patients compared to that observed in controls. AS fibroblasts exhibited excessive proliferation, a higher growth rate, and a decreased apoptotic rate. EdU assay demonstrated that DKK-1 suppressed the growth of AS fibroblasts. Downregulation of DKK-1 decreased the phosphorylation of ß-catenin and upregulated the expression of ß-catenin, c-Myc, cyclin D1, and osteogenesis markers. Overexpression of DKK-1 had the opposite effect, resulting in the inhibition of the Wnt/ß-catenin pathway. ARS showed an increase in biomineralization activity after the inhibition of DKK-1. CONCLUSIONS: AS fibroblasts are characterized by an imbalance between proliferation and apoptosis. DKK-1 may play a role in switching to new bone formation in AS progression.

Attenuated synovial fluid ghrelin levels are linked with cartilage damage, meniscus injury, and clinical symptoms in patients with knee anterior cruciate ligament deficiency.

BACKGROUND: The meniscus injury and post-traumatic knee osteoarthritis (PTOA) following anterior cruciate ligament (ACL) lesions often cause great burdens to patients. Ghrelin, a recently identified 28-amino-acid peptide, has been shown to inhibit inflammation and perform as a growth factor for chondrocyte. OBJECTIVE: This study was aimed at investigating ghrelin concentration in synovial fluid and its association with the degree of meniscus injury, articular degeneration, and clinical severity in patients suffering from anterior cruciate ligament (ACL) deficiency. METHODS: 61 ACL deficiency patients admitted to our hospital were drafted in the current study. The Noyes scale and Mankin scores were used to assess articular cartilage damage arthroscopically and histopathologically, respectively. The Lysholm scores and International Knee Documentation Committee (IKDC) subjective scores were utilized to evaluate the clinical severity. The radiological severity of meniscus injury was assessed by MR imaging. Serum and synovial fluid ghrelin levels were determined using enzyme linked immunosorbent assay (ELISA). The cartilage degradation markers collagen type II C-telopeptide (CTX-II) and cartilage oligomeric matrix protein (COMP) in addition to inflammatory markers interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were also examined. Receiver operating characteristic (ROC) curve was performed and the area under curve (AUC) was calculated to assess the diagnostic value of ghrelin levels for the prediction of the MRI grading for meniscus injury by comparing with other biomarkers. RESULTS: SF ghrelin levels were positively related to Lysholm and IKDC scores. PTOA patients with grade 3 showed significantly decreased levels of ghrelin in SF compared with those with grade 2. The ghrelin levels in SF were negatively related to MRI signal grades for meniscus injury. SF ghrelin levels were also inversely associated with Noyes scale and Mankin scores, and levels of inflammation markers IL-6, TNF-α, and degradation biomarkers COMP and CTX-II. ROC analysis showed that ghrelin was more valuable for severe meniscus injury diagnosis by MRI imaging. CONCLUSIONS: Synovial fluid ghrelin levels demonstrated an independent and negative association with meniscus injury, cartilage damage, and clinical severity in patients with ACL deficiency. Ghrelin in SF might serve as a potential cartilage protective factor for PTOA. Local application of ghrelin as a potential adjuvant therapy for delaying cartilage degeneration following ACL injury deserves further study.

Correlation of fractalkine concentrations in serum and synovial fluid with the radiographic severity of knee osteoarthritis.

BACKGROUND: Fractalkine has been detected in synovial fluid (SF) from osteoarthritis (OA) patients. This study aims to examine the relation of fractalkine concentrations in serum and SF with the radiographic severity of OA. METHODS: Fractalkine concentrations of serum and SF were measured using an enzyme-linked immunosorbent assay method in 223 patients with knee OA and 165 healthy controls. The progression of OA was classified according to the Kellgren-Lawrence grading system. RESULTS: Elevated concentrations of fractalkine in serum were found in knee OA patients compared with healthy controls [all results median (interquartile range) 226.25 (183.19-259.91) vs. 127.42 (99.54-154.98) pg/mL, P < 0.001]. The case group included 71 knee OA patients with grade 2, 98 with grade 3, and 54 with grade 4. Knee OA patients with KL grade 4 had significantly higher fractalkine concentrations in serum and SF compared with those with KL grade 2 and 3 [serum: 247.68 (215.05-278.64) vs. 212.45 (169.19-247.96) pg/mL, P < 0.001, and 247.68 (215.05-278.64) vs. 222.00 (179.80-254.98) pg/mL, P = 0.005, respectively; SF: 94.95 (76.46-106.68) vs. 74.31 (63.64-84.79) pg/mL, P < 0.001, and 94.95 (76.46-106.68) vs. 80.34 (68.84-96.39) pg/mL, P = 0.001, respectively]. Knee OA patients with KL grade 3 showed significantly elevated concentrations of fractalkine in SF compared with those with KL grade 2 [80.34 (68.84-96.39) vs. 74.31 (63.64-84.79) pg/mL, P = 0.004]. Fractalkine concentrations in serum and SF of knee OA patients were both significantly associated with the disease severity evaluated by KL grading criteria (r = 0.261, P < 0.001 and r = 0.366, P < 0.001, respectively). CONCLUSION: The fractalkine concentrations in serum and SF may serve as an effective biomarker for the severity of OA.