Matched Stochastic Resonance Enhanced Underwater Passive Sonar Detection under Non-Gaussian Impulsive Background Noise.

Remote passive sonar detection with low-frequency band spectral lines has attracted much attention, while complex low-frequency non-Gaussian impulsive noisy environments would strongly affect the detection performance. This is a challenging problem in weak signal detection, especially for the high false alarm rate caused by heavy-tailed impulsive noise. In this paper, a novel matched stochastic resonance (MSR)-based weak signal detection model is established, and two MSR-based detectors named MSR-PED and MSR-PSNR are proposed based on a theoretical analysis of the MSR output response. Comprehensive detection performance analyses in both Gasussian and non-Gaussian impulsive noise conditions are presented, which revealed the superior performance of our proposed detector under non-Gasussian impulsive noise. Numerical analysis and application verification have revealed the superior detection performance with the proposed MSR-PSNR detector compared with energy-based detection methods, which can break through the high false alarm rate problem caused by heavy-tailed impulsive noise. For a typical non-Gasussian impulsive noise assumption with α=1.5, the proposed MSR-PED and MSR-PSNR can achieve approximately 16 dB and 22 dB improvements, respectively, in the detection performance compared to the classical PED method. For stronger, non-Gaussian impulsive noise conditions corresponding to α=1, the improvement in detection performance can be more significant. Our proposed MSR-PSNR methods can overcome the challenging problem of a high false alarm rate caused by heavy-tailed impulsive noise. This work can lay a solid foundation for breaking through the challenges of underwater passive sonar detection under non-Gaussian impulsive background noise, and can provide important guidance for future research work.

Decompression-first or direct enucleation: The choice of treatment for medium-sized odontogenic jaw cysts.

BACKGROUND: The treatment of medium-sized odontogenic jaw cysts is inconsistent at present. Two main treatments, namely decompression and enucleation, are used overlappingly. This retrospective analysis aims to provide useful references for technique selection for future management of medium-sized odontogenic jaw cysts. METHODS: Odontogenic cysts with lesion sizes ranging 2-4 cm were included. The clinical and radiological data of the patients were reviewed. Decompression-first and direct enucleation treatments were the two main surgical techniques. The preoperative parameters and postoperative outcomes were compared between the two groups. RESULTS: Out of 69 patients included, 40 (58 %) were in the decompression group and 29 (42 %) in direct enucleation group. The logistic regression analysis of preoperative parameters demonstrated that the maximum lesion size and the chief surgeon's preference could affect the selection of surgical techniques for medium-sized cysts (P < 0.05). Receiver operating characteristic curve analyses demonstrated that a lesion size >2.5 cm was the best cutoff value for predicting a decompression selection. Most postoperative outcomes differed significantly between the two groups (P < 0.05). Lower-risk anesthesia, shorter hospitalization, tooth function protection, and fewer neurosensory impairments were decompression-favoring outcomes. However, more follow-up visits, more postoperative X-rays, and longer postoperative care were outcomes against decompression. The recurrence rate was low and did not differ significantly between the two groups (P > 0.05). CONCLUSIONS: There is no apparent preference for treating medium-sized jaw cysts. The maximum lesion size is a moderate-impact factor for treatment selection. A tendency to prefer decompression-first with larger lesion size was found in medium-sized jaw cysts. The advantages of teeth preservation and low neurosensory impairment of decompression were verified in the medium-size jaw cysts. The burden of postoperative care should be considered when selecting decompression.

Application of a modified osteotomy and positioning integrative template system (MOPITS) based on a truncatable reconstruction model in the precise mandibular reconstruction with fibula free flap: a pilot clinical study.

BACKGROUND: Mandibular defects can greatly affect patients' appearance and functionality. The preferred method to address this issue is reconstructive surgery using a fibular flap. The current personalized guide plate can improve the accuracy of osteotomy and reconstruction, but there are still some problems such as complex design process and time-consuming. Therefore, we modified the conventional template to serve the dual purpose of guiding the mandible and fibula osteotomy and facilitating the placement of the pre-bent titanium. METHODS: The surgery was simulated preoperatively using Computer-Aided Design (CAD) technology. The template and truncatable reconstruction model were produced in the laboratory using 3D printing. After pre-bending the titanium plate according to the contour, the reconstruction model was truncated and the screw trajectory was transferred to form a modified osteotomy and positioning integrative template system (MOPITS). Next, the patient underwent a composite template-guided vascularized fibula flap reconstruction of the mandible. All cases were reviewed for the total operative time and accuracy of surgery. RESULTS: The procedures involved 2-4 fibular segments in 15 patients, averaging 3 fibular segments per procedure. The osteotomy error is 1.01 ± 1.02 mm, while the reconstruction angular error is 1.85 ± 1.69°. The preoperative and postoperative data were compared, and both p > 0.05. During the same operation, implant placement was performed on four patients, with an average operative time of 487.25 ± 60.84 min. The remaining malignant tumor patients had an average operative time of 397.18 ± 73.09 min. The average postoperative hospital stay was 12.95 ± 3.29 days. CONCLUSIONS: This study demonstrates the effectiveness of MOPITS in facilitating precise preoperative planning and intraoperative execution of fibula flap reconstruction. MOPITS represents a promising and reliable tool for reconstructive surgery, particularly for inexperienced surgeons navigating the challenges of mandible defect reconstruction.

Giant calcifying epithelial odontogenic tumor after I-125 seed implantation: A case report.

Calcifying Epithelial Odontogenic Tumor (CEOT), also known as Pindborg tumor, is a rare odontogenic benign tumor. It was first reported by Thoma and Goldman in 1946 and defined as an independent tumor by Pindborg in 1957. Herein, we reported a CEOT case involving most of the mandible after I-125 implantation in a 53-year-old man. We cooperated with governmental and hospital departments to resect the tumors, reconstruct the mandible with a fibular flap graft, and properly dispose of the radioactive particles.

Evaluation of Er:YAG laser energy transmitted through novel dental zirconia ceramics.

Erbium:yttrium-aluminum-garnet (Er:YAG) laser debonding is a promising removal method in prosthodontics. This study aimed to assess Er:YAG laser energy transmission through novel zirconia ceramics. Five types of ceramic samples: lithium disilicate ceramic (LDC), self-glazed zirconia (SGZ), 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), 4Y-TZP and 5Y-TZP with 5 thicknesses (0.5, 1.0, 1.5, 2.0, 2.5 mm) and 2 shades (A1, A3), 50 specimens total, were made. Fourier transformation infrared absorption spectra were obtained for each ceramic type, and Er:YAG laser energy transmission tests were conducted for each specimen. The novel zirconia ceramic (SGZ, 4Y-TZP, 5Y-TZP) transmission ranged from 40%-60%. The transmitted laser energy decreased with increasing ceramic thickness, and the differences between different shades were significant (p<0.05). The novel zirconias had a higher translucency than 3Y-TZP at any given thickness and shade, and when the thickness was >1.5 mm, the novel zirconias had a higher translucency than LDC.

Long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional analysis.

BACKGROUND: Decompression is an effective treatment for jaw cysts. Many studies have reported its effectiveness as a preliminary treatment followed by secondary enucleation. This study aimed to explore long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional (3D) analysis. METHODS: This was a retrospective study. The clinical and radiological data of patients with jaw cysts who underwent decompression and were followed up for two years or more at Peking Union Medical College Hospital between January 2015 and December 2020 were reviewed. The 3D radiological data before and after decompression were analyzed to study the long-term reduction in cysts, especially after one year of decompression. RESULTS: A total of 17 patients with jaw cysts were included in this study. The radiological data showed a mean reduction rate of 78% one year after decompression. At the final examination, which was 36.1 months after decompression on average, the mean reduction rate was 86%. The unossified lesions could still ossify slowly after one year of decompression. The recurrence rate was 5.9% (1/17). CONCLUSIONS: Bone remodeling continued for a long time after decompression. Definitive decompression could be an option for most patients with jaw cysts. Long-term follow-up is required.

Self-fused concatenation of interferon with enhanced bioactivity, pharmacokinetics and antitumor efficacy.

We report an easy but universal protein modification approach, self-fused concatenation (SEC), to biosynthesize a set of interferon (IFN) concatemers with improved in vitro bioactivity, in vivo pharmacokinetics and therapeutic efficacy over the monomeric IFN, and the results can be positively enhanced by the concatenated number of self-fused proteins.

A General Way to Fabricate Chain-like Ferrite with Ultralow Conductive Percolation Threshold and Wideband Absorbing Ability.

The magnetic nanochain-like material has been regards as one of the most promising electromagnetic (EM) absorbing material but remains a challenging. Herein, magnetic chain-like ferrite (included Fe3O4, CoFe2O4 and NiFe2O4) are successfully produced through a general solvothermal method, using PVP as the structural-liking agent. Experimental results confirm the ultimate sample possess a 3-dimensional chain-like structure which are constructed by numerous ferrite's nanoparticles with ~60 nm in diameter. Their electromagnetic parameters can be also manipulated by such a chain structure, especially the dielectric loss, where a sharply increases can be observed on within a lower filling ratio. It greatly benefits to the EM absorbing property. In this article, the electromagnetic absorption layer made with a lower content of ferrite possess the excellent electromagnetic absorption ability, where the optimized effective absorption band was nearly 6.4 GHz under a thickness of 1.8 mm. Moreover, the filling ratio is only 30 wt%. Our method for designing of chain-like magnetic material can be helpful for producing wideband electromagnetic absorption in a low filling ratio.

Genome-wide identification, evolutionary and functional analyses of KFB family members in potato.

BACKGROUND: Kelch repeat F-box (KFB) proteins play vital roles in the regulation of multitudinous biochemical and physiological processes in plants, including growth and development, stress response and secondary metabolism. Multiple KFBs have been characterized in various plant species, but the family members and functions have not been systematically identified and analyzed in potato. RESULTS: Genome and transcriptome analyses of StKFB gene family were conducted to dissect the structure, evolution and function of the StKFBs in Solanum tuberosum L. Totally, 44 StKFB members were identified and were classified into 5 groups. The chromosomal localization analysis showed that the 44 StKFB genes were located on 12 chromosomes of potato. Among these genes, two pairs of genes (StKFB15/16 and StKFB40/41) were predicted to be tandemly duplicated genes, and one pair of genes (StKFB15/29) was segmentally duplicated genes. The syntenic analysis showed that the KFBs in potato were closely related to the KFBs in tomato and pepper. Expression profiles of the StKFBs in 13 different tissues and in potato plants with different treatments uncovered distinct spatial expression patterns of these genes and their potential roles in response to various stresses, respectively. Multiple StKFB genes were differentially expressed in yellow- (cultivar 'Jin-16'), red- (cultivar 'Red rose-2') and purple-fleshed (cultivar 'Xisen-8') potato tubers, suggesting that they may play important roles in the regulation of anthocyanin biosynthesis in potato. CONCLUSIONS: This study reports the structure, evolution and expression characteristics of the KFB family in potato. These findings pave the way for further investigation of functional mechanisms of StKFBs, and also provide candidate genes for potato genetic improvement.

Effectiveness of case-based learning in Chinese dental education: a systematic review and meta-analysis.

OBJECTIVE: The application of case-based learning (CBL) pedagogy has been emerging as an improved and more practical learning method across the Chinese dental education system. This article provides a critical overview of CBL pedagogy and further assesses the effectiveness of this teaching model in Chinese dental education. DESIGN: A systematic review and meta-analysis. METHODS: Studies published up to December 2019 were searched in the following electronic databases: China National Knowledge Infrastructure, China Science Periodical Database, Chinese Biomedical documental database, Wanfang data, PubMed, EMBASE and Cochrane Central Register of Control Trials. All randomised controlled trials (RCTs) that compared the effectiveness of the CBL teaching model and the traditional lecture-based learning (LBL) model in all dental disciplines were included. The assessment of methodological quality was based on the guidelines described in the Cochrane Handbook for Systematic Reviews, and the meta-analysis was performed using the software RevMan V.5.3 RESULTS: A total of 30 RCTs were finally included, with a total sample size of 2356 dental students. The CBL pedagogy significantly increased knowledge scores (standardised mean difference (SMD)=1.58, 95% CI: 0.95 to 2.20, p<0.0001), skill scores (SMD=1.22, 95% CI: 0.34 to 2.11, p<0.0001), comprehensive ability scores (SMD=1.91, 95% CI: 1.74 to 4.07, p<0.0001) and teaching satisfaction (risk ratio=1.38; 95% CI: 1.15 to 1.65; p=0.01) compared with the LBL teaching model among the dental students. Additionally, a subgroup analysis showed significant differences in the effects of CBL on knowledge scores, skill scores and comprehensive ability scores when comparing theoretical and practical courses. CONCLUSIONS: The meta-analysis and systematic review of the eligible literature showed that the CBL pedagogy in Chinese dental education is an effective way to increase knowledge scores, skill scores, comprehensive ability scores and teaching satisfaction. Successful adaptation of this teaching model could solve the scarcity of highly skilled and professional dentists in dental schools and hospitals across China.

Enhancement of bioactivity, thermal stability and tumor retention by self-fused concatenation of green fluorescent protein.

The widespread application of protein and peptide therapeutics is hampered by their poor stability, strong immunogenicity and short half-life. However, the existing protein modification technologies require the introduction of exogenous macromolecules, resulting in inevitable immunogenicity and decreased bioactivity. Herein, we reported an easy but universal protein modification approach, self-fused concatenation (SEC), to enhance the in vitro thermal stability and in vivo tumor retention of proteins. In this proof of concept study, we successfully obtained a set of green fluorescence protein (GFP) concatemers, monomer (GFP 1), dimer (GFP 2) and trimer (GFP 3) of GFP, and systematically studied the effects of SEC on the biological activity and stability of GFP. Notably, GFP concatemers displayed remarkable improvement in in vitro bioactivity and thermal stability over the monomeric GFP. In a murine tumor model, GFP 2 and GFP 3 exhibited significantly prolonged duration, with increases of 220- and 381-fold relative to GFP 1 in tumor retention 4 h after administration. Furthermore, the biological activity, thermal stability and tumor retention can be enhanced by the concatenated number of self-fused proteins. These findings demonstrate that SEC may be a promising alternative to design advanced protein and peptide therapeutics with enhanced pharmaceutic profiles.

The Early Adhesion Effects of Human Gingival Fibroblasts on Bovine Serum Albumin Loaded Hydrogenated Titanium Nanotube Surface.

The soft tissue sealing at the transmucal portion of implants is vital for the long-term stability of implants. Hydrogenated titanium nanotubes (H2-TNTs) as implant surface treatments were proved to promote the adhesion of human gingival fibroblasts (HGFs) and have broad usage as drug delivery systems. Bovine serum albumin (BSA) as the most abundant albumin in body fluid was crucial for cell adhesion and was demonstrated as a normal loading protein. As the first protein arriving on the surface of the implant, albumin plays an important role in initial adhesion of soft tissue cells, it is also a common carrier, transferring and loading different endogenous and exogenous substances, ions, drugs, and other small molecules. The aim of the present work was to investigate whether BSA-loaded H2-TNTs could promote the early adhesion of HGFs; H2-TNTs were obtained by hydrogenated anodized titanium dioxide nanotubes (TNTs) in thermal treatment, and BSA was loaded in the nanotubes by vacuum drying; our results showed that the superhydrophilicity of H2-TNTs is conducive to the loading of BSA. In both hydrogenated titanium nanotubes and non-hydrogenated titanium nanotubes, a high rate of release was observed over the first hour, followed by a period of slow and sustained release; however, BSA-loading inhibits the early adhesion of human gingival fibroblasts, and H2-TNTs has the best promoting effect on cell adhesion. With the release of BSA after 4 h, the inhibitory effect of BSA on cell adhesion was weakened.

Associations of low level of fluoride exposure with dental fluorosis among U.S. children and adolescents, NHANES 2015-2016.

Drinking water fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride at the teeth forming years provided protection against dental decays. Numerous studies showed that high level exposure to fluoride could cause dental and skeleton fluorosis. However, there was limited study focusing on the fluorosis effect of low levels of exposure to fluoride. Therefore, our study aimed to examine whether the low level of fluoride exposure (measured in blood plasma and household tap water) was associated with the risk of dental fluorosis based on data of the National Health and Nutrition Examination Survey (NHANES) 2015-2016. We analyzed data in 2098 children and adolescents who had Dean's Index scores, and water and plasma fluoride measures. The Dean's Index score was measured by calibrated dental examiners using the modified Dean's fluorosis classification system. Fluoride was measured in plasma and household tap water. In this study, we found that the rate of fluoride concentration in water above the recommended level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. Binary logistic regression adjusted for covariates showed that higher water fluoride concentrations (0.31-0.50, 0.51-0.70, > 0.70 compared 0.00-0.30) were associated with higher odds of dental fluorosis (OR = 1.48, 95% CI: 1.13-1.96, p = 0.005; OR = 1.92, 95% CI: 1.44-2.58, p < 0.001, and OR = 2.30, 95% CI: 1.75-3.07, p < 0.001, respectively). The pattern of regression between plasma fluoride and dental fluorosis was similar. Inclusion, our study showed that even low level of water or plasma fluoride exposure was associated with increased the risk of dental fluorosis. The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.

Effects of laser debonding treatment on the optical and mechanical properties of all-ceramic restorations.

The objective of this study was to evaluate how erbium-doped yttrium aluminium garnet (Er:YAG) laser debonding treatment affects the optical and mechanical properties of dental ceramics. In total, 120 rectangular (22*5*1.2 mm) IPS E.max Press specimens were fabricated and divided into 4 groups: the control group, 3 W laser group, 4 W laser group, and 5 W laser group. For each group, 10 specimens were used for the colour test (colour difference (△E) and transparency parameter (TP)), 10 specimens were used for the flexural strength test, and 10 were used for the Vickers hardness test. One random sample from each colour test specimens was observed by scanning electron microscopy (SEM). The L*, a*, b*, △E, TP, flexural strength, and Vickers hardness values were measured and calculated. According to the Kruskal-Wallis test, the L*, a*, and b* values showed no significant variations (P > 0.05), except for the b* value in the 5 W laser group (P < 0.05). The △E, TP, flexural strength, and Vickers hardness values were analysed by one-way analysis of variance (ANOVA). The 5 W laser group exhibited a higher △E value, which exceeded the perceptible threshold and significantly lower TP values than the other groups (P < 0.05). The mean flexural strength and Vickers hardness values after Er:YAG laser debonding revealed no significant changes (P > 0.05). Microcracks were detected during the SEM analysis of the 5 W laser group. Er:YAG laser debonding treatment did not affect the mechanical properties, but changed the optical properties of dental ceramics.

The development of a magnetic iron/nitrogen-doped graphitized carbon composite with boosted microwave attenuation ability as the wideband microwave absorber.

Magnetic carbon-based composites have been attractive candidates for electromagnetic (EM) absorption due to their dual magnetic and dielectric loss ability. In this study, a novel magnetic carbon consisting of N-doped graphitized carbon and magnetic Fe nanoparticles was produced. First, the graphitized carbon doped with N has been demonstrated to be an efficient way to strengthen the conductivity loss ability. Based on the N-doped graphitized carbon (NGC), the magnetic Fe nanoparticles were further decorated on the NGC, which was not only favored the dielectric loss ability but also introduced the magnetic loss ability. The electromagnetic absorbing properties of the NGC-Fe nanoparticles were evaluated in the frequency range of 2-18 GHz, and as expected, the sample exhibited the excellent wideband EM absorbing ability, with an effective absorption region of 5.2 GHz under a thickness of 1.2 mm. Ulilization of element doping method consisted to modify magnetic carbon material can be a candidate for producing wideband EM absorbers but showing thin thickness.

Adaptive Intrawell Matched Stochastic Resonance with a Potential Constraint Aided Line Enhancer for Passive Sonars.

Remote passive sonar detection and classification are challenging problems that require the user to extract signatures under low signal-to-noise (SNR) ratio conditions. Adaptive line enhancers (ALEs) have been widely utilized in passive sonars for enhancing narrowband discrete components, but the performance is limited. In this paper, we propose an adaptive intrawell matched stochastic resonance (AIMSR) method, aiming to break through the limitation of the conventional ALE by nonlinear filtering effects. To make it practically applicable, we addressed two problems: (1) the parameterized implementation of stochastic resonance (SR) under the low sampling rate condition and (2) the feasibility of realization in an embedded system with low computational complexity. For the first problem, the framework of intrawell matched stochastic resonance with potential constraint is implemented with three distinct merits: (a) it can ease the insufficient time-scale matching constraint so as to weaken the uncertain affect on potential parameter tuning; (b) the inaccurate noise intensity estimation can be eased; (c) it can release the limitation on system response which allows a higher input frequency in breaking through the large sampling rate limitation. For the second problem, we assumed a particular case to ease the potential parameter a o p t = 1 . As a result, the computation complexity is greatly reduced, and the extremely large parameter limitation is relaxed simultaneously. Simulation analyses are conducted with a discrete line signature and harmonic related line signature that reflect the superior filtering performance with limited sampling rate conditions; without loss of generality of detection, we considered two circumstances corresponding to H 1 (periodic signal with noise) and H 0 (pure noise) hypotheses, respectively, which indicates the detection performance fairly well. Application verification was experimentally conducted in a reservoir with an autonomous underwater vehicle (AUV) to validate the feasibility and efficiency of the proposed method. The results indicate that the proposed method surpasses the conventional ALE method in lower frequency contexts, where there is about 10 dB improvement for the fundamental frequency in the sense of power spectrum density (PSD).

Addition of cholesterol loaded cyclodextrin prior to GV-phase vitrification improves the quality of mature porcine oocytes in vitro.

The purpose of this study was to determine whether the mitochondrial membrane potential, pro-apoptotic gene expression, and ubiquitylation status of zona pellucida proteins (ZP1, ZP2, and ZP3) of vitrified GV-stage mature oocytes could be protected by treatment with cholesterol-loaded methyl-ß-cyclodextrin (CLC) prior to vitrification. Porcine GV oocytes were treated with CLC prior to the vitrification process, and the effects on the mitochondrial membrane potential and ZP ubiquitylation status were determined by JC-1 single staining and western blot assays. We found that porcine GV-stage oocytes were treated with CLC at different concentrations (0.5, 5, and 10 mg/mL) prior to vitrification improved in vitro maturation of these oocytes (P < 0.05). The mitochondrial membrane potential of matured oocyte without vitrification or treated with 5 mg/mL CLC vitrification treatment was higher than that of the 0 mg/mL CLC group and other treatment groups (vitrified) (P < 0.05). The expression of Caspase 3, Caspase 8, and Caspase 9 genes in the high concentration CLC treatment groups (5 and 10 mg/mL) was significantly lower than that in the 0 (vitrified) mg/mL CLC group (P < 0.05). ZPs protein and ZP3 protein ubiquitylation were also higher in the non-vitrified controls, 5 and 10 mg/mL CLC-treated oocytes than in the 0 (vitrified) and 0.5 mg/mL vitrified groups (P < 0.05). Whereas the sperm-oocyte binding capacity was improved in the CLC treatment groups (P < 0.05) but the embryonic development rate was not improved. In conclusion, pretreatment with CLC can improve the survival rate and maturation rate of oocytes and protect their mitochondria and zona pellucida of porcine oocytes from cryodamage during the vitrification process.

[Follow-up study on autogenous osteochondral transplantation for cartilage defect of knee joint].

OBJECTIVE: To evaluate clinical effect of autologous osteochondral transplantation in treating localized knee cartilage defects. METHODS: Fifteen patients with knee cartilage defects were treated by autologous osteochondral transplantation from January 2007 to January 2008, including 8 females and 7 males, aged from 23 to 45 years old. Preoperative and postoperative KSS score at 10 years were compared. RESULTS: All patients were followed up for 10.0 to 10.7 years, with an average of(10.2±0.3) years. Clinical score of KSS was improved from 38.86±4.09 to 85.07±2.19 at 10 years after operation(P<0.05), functional score increased from 3.33±4.88 to 82.67±4.58 at 10 years after operation(P<0.05), KSS score was improved form 42.20±7.84 befor operation to 167.73±6.29 at 10 years after operation, and had statistical differences before and after operation. While there was no statistical difference in stability of knee joint(P>0.05). All patients had no other complications. CONCLUSIONS: Through long-term follow-up of patients with cartilage defect in knee treated by autologous bone cartilage transplantation showed that this method could effectively improve function of knee joint and alleviate pain. So it is an effective method for repair of osteochondral defect.

Evaluation of the degradation, biocompatibility and osteogenesis behavior of lithium-doped calcium polyphosphate for bone tissue engineering.

BACKGROUND: Calcium polyphosphate (CPP) is a commonly used biomaterial in bone tissue engineering, but CPP is insufficient in osteoinduction. This study aimed to fabricate lithium doped CPP (LiCPP) scaffolds and assess their characterization, degradation, biocompatibility and osteogenesis behavior for bone tissue engineering. METHODS: The novel scaffold was characterized by XRD, FTIR and SEM. The porosity, cell mediated degradation behavior and mechanical properties were also investigated. Meanwhile, cell proliferation activity and adhesion in vitro was exploited. Finally, osteogenesis the LiCPP scaffolds in vitro and in vivo was researched. RESULTS: The outcomes revealed that low-content Li doping had no significant influence on the structure of CPP. The results of cells mediated degradation experiments from the weight loss and the release of ions indicated that Li doped CPP improved biological degradation. The compressive strength of CPP with 66% porosity was improved to 7 MPa. Cells proliferation experiment and adhesion experiment demonstrated 2.0%LiCPP scaffold was most beneficial to cell growth and attachment. Furthermore, Li doped CPP up-regulated Wnt signal pathway when co-cultured with MG63 and increased osteogenic marker ALP expression and calcium phosphate deposition in vitro. At the same time, new bone formation in vivo was also enhanced by using LiCPP scaffolds and the 2.0%LiCPP scaffolds obtained best osteogenesis outcomes. CONCLUSION: The results obtained in our study suggest that 2.0%LiCPP scaffold could benefit from improving the osteogenesis behavior and is a promising biomaterial for bone repairing applications.