Bone cement distribution may significantly affect the efficacy of percutaneous vertebroplasty in treating symptomatic Schmorl's nodes.

PURPOSE: Percutaneous vertebroplasty(PVP) has been widely used in treating symptomatic Schmorl's nodes(SNs). However, there were still some patients with poor pain relief. At present, there is a lack of research to analyze the reasons for poor efficacy. METHODS: Review the SNs patients treated with PVP in our hospital from November 2019 to June 2022, collect their baseline data. Reverse reconstruction software was used to calculate the filling rate of bone edema ring(Rf). NRS score was used to evaluate pain and ODI to evaluate function. The patients were divided into remission group(RG) and non remission group(n-RG) according to symptom. In addition, according to the Rf, they were divided into excellent, good and poor groups. Differences between groups were investigated. RESULTS: A total of 26 vertebrae were included in 24 patients. When grouped according to symptoms, patients in n-RG were older, and surgical segments were tend to locate in lower lumbar spine. The proportion of Poor distribution was significantly higher. When grouped according to the cement distribution, the preoperative NRS and ODI of the three groups were comparable, but the NRS and ODI of Poor group were significantly worse than the Excellent and Good groups postoperatively and at the last follow-up. CONCLUSIONS: The cement distribution may significantly affect the efficacy of PVP in treating symptomatic SNs. We suggest that the bone edema ring should be filled as fully as possible to ensure the efficacy. In addition, advanced age and low lumbar lesions are also adverse factors for clinical outcomes.

Mercapto-functionalized ordered mesoporous silica-modified PVDF membrane for efficiently scavenging Cd2+ from water.

In this study, (3-mercaptopropyl) triethoxysilane (MPTMS)-modified ordered mesoporous silica (OMS) materials were prepared using a post-grifting method, with MPTMS as the organic functionalized reagent. The OMS materials were analyzed by FT-IR spectra, N2 sorption, and small angle X-ray scattering to evaluate their potential for scavenging Cd2+ from water. Moreover, a (3-mercaptopropyl) triethoxysilane-functionalized ordered mesoporous silica modified polyvinylidene fluoride (MPTMS-OMS/PVDF) membrane was synthesized using the solvent phase inversion method to remediate wastewater containing heavy metal ions. The MPTMS-OMS was characterized by a maximum specific surface area of 422 m2/g, high surface hydrophilicity, and high pure water flux. The MPTMS-OMS/PVDF exhibited a dynamic adsorption capacity for Cd2+ in water. At an MPTMS-OMS content of 5 wt%, the Cd2+ removal efficiency was 90%, whereas the pure PVDF showed no Cd2+ adsorption capacity. These results highlight the potential of the MPTMS-OMS/PVDF membrane to eliminate Cd2+ during the decontamination of aqueous streams containing low-concentrations of contaminants.

Facile On-Site Aqueous Pollutant Monitoring Using a Flexible, Ultralight, and Robust Surface-Enhanced Raman Spectroscopy Substrate: Interface Self-Assembly of Au@Ag Nanocubes on a Polyvinyl Chloride Template.

Aquatic ecosystems and human health have been seriously threatened by illegal discharge of wastewater, while simple and effective monitoring methods are still sparse. Here, we propose a facile method for on-site pollutant monitoring by surface-enhanced Raman spectroscopy with a novel substrate. This substrate is fabricated by interface self-assembly of Au@Ag nanocubes (NCs) on a simultaneously formed polyvinyl chloride (PVC) template, followed by coating with a thin Au film. The Au@Ag@Au-NCs/PVC film is flexible, ultralight, and robust and could float on the surface of water and firmly contact with water even under harsh environmental conditions. Moreover, the Au@Ag@Au-NCs/PVC film is translucent, allowing penetration of laser beams and enhancement of Raman signals. When thiram was used as a model contaminant in aqueous solution, a good linear relationship ( R2 = 0.972) was obtained over the range of 0.1-50 ppb with a detection limit of 0.1 ppb. Raman signals of thiram can be instantly and consecutively detected with the enhancement of the film in the simulated experiments, suggesting its possible use in the long run. Furthermore, the film can be easily regenerated by NaBH4 solution washing, which could reduce the operating cost. In summary, the Au@Ag@Au-NCs/PVC film has great potential in on-site pollutant monitoring in aqueous environments with a portable Raman spectrometer.

Programmable co-delivery of the immune checkpoint inhibitor NLG919 and chemotherapeutic doxorubicin via a redox-responsive immunostimulatory polymeric prodrug carrier.

To achieve synergistic therapeutic efficacy and prevent cancer relapse, chemotherapy and immunotherapy have been combined as a new modality for tumor treatment. In this work, we designed a redox-responsive immunostimulatory polymeric prodrug carrier, PSSN10, for programmable co-delivery of an immune checkpoint inhibitor NLG919 (NLG) and a chemotherapeutic doxorubicin (DOX). NLG-containing PSSN10 prodrug polymers were self-assembled into nano-sized micelles that served as a carrier to load DOX (DOX/PSSN10 micelles). DOX/PSSN10 micelles displayed spherical morphology with a size of ∼170 nm. DOX was effectively loaded into PSSN10 micelles with a loading efficiency of 84.0%. In vitro DOX release studies showed that rapid drug release could be achieved in the highly redox environment after intracellular uptake by tumor cells. In 4T1.2 tumor-bearing mice, DOX/PSSN10 micelles exhibited greater accumulation of DOX and NLG in the tumor tissues compared with other organs. The PSSN10 carrier dose-dependently enhanced T-cell immune responses in the lymphocyte-Panc02 co-culture experiments, and significantly inhibited tumor growth in vivo. DOX/PSSN10 micelles showed potent cytotoxicity in vitro against 4T1.2 mouse breast cancer cells and PC-3 human prostate cancer cells comparable to that of DOX. In 4T1.2 tumor-bearing mice, DOX/PSSN10 mixed micelles (5 mg DOX/kg, iv) was more effective than DOXIL (a clinical formulation of liposomal DOX) or free DOX in inhibiting the tumor growth and prolonging the survival of the treated mice. In addition, a more immunoactive tumor microenvironment was observed in the mice treated with PSSN10 or DOX/PSSN10 micelles compared with the other treatment groups. In conclusion, systemic delivery of DOX via PSSN10 nanocarrier results in synergistic anti-tumor activity.

Self-assembly of Au nanoparticles on PMMA template as flexible, transparent, and highly active SERS substrates.

We report a simple and rapid method for fabricating a surface-enhanced Raman scattering (SERS) substrate, which offers good flexibility, excellent optical transparency, and high SERS activity. Specifically, the SERS substrate (AuNPs/PMMA film) was obtained through self-assembly of gold nanoparticles (AuNPs) on newborn poly(methyl methacrylate) (PMMA) template. The UV-vis spectroscopy analysis and scanning electron microscopy observation revealed that the gold nanoparticles were closely assembled on the flexible and transparent PMMA template. The fabricated AuNPs/PMMA film SERS substrate allowed detection of model molecule, malachite green isothiocyanate, at a concentration as low as 0.1 nM, and exhibited good reproducibility in the SERS measurement. The Raman enhancement factor (EF) of the AuNPs/PMMA film was found to be as high as (2.4 ± 0.3) × 10(7). In addition, measure of residual malachite green on fish surface was carried out, and the result indicated that the AuNPs/PMMA film had great potential in the in situ ultrasensitive detection of analyte on irregular objects.

[Study of rapid prediction of wood surface glossiness by near infrared spectroscopy].

Surface glossiness is one of the important visual appearance parameters of natural polymer material (wood) and its related products. To realize the fast measurement of natural polymer material surface glossiness is of great significance to the online quality control and assessment of its surface. In order to broaden the application of near infrared (NIR) spectroscopy in the field of polymer material surface quality control and realize the feasibility of NIR as a fast measurement of surface glossiness, the NIR combined with partial least squares (PLS) analysis were used to analyse the correlations of natural polymer material wood surface glossiness between the NIR predicted and lab measured, and then to investigate the feasibility of NIR to rapidly predict the surface glossiness of natural polymer material wood. The results showed that the wood NIR diffuse reflectance spectroscopy regularly varied with the different wood surface glossiness, from which we can concluded that the NIR spectrums reflected the information of wood surface glossiness. The correlation coefficients of surface glossiness between the PLS models predicted and lab measured were up to 0.90. Additionally, by changing the degree between the fiber and sample surface, we collected the different wood NIR spectrums, the accuracy of NIR surface glossiness models based on these NIR spectrums had not significantly improved, and models based on the NIR spectrums collected by the 90 degree between the fiber and sample surface performed better.

Lignin: A multi-faceted role/function in 3D printing inks.

3D printing technology demonstrates significant potential for the rapid fabrication of tailored geometric structures. Nevertheless, the prevalent use of fossil-derived compositions in printable inks within the realm of 3D printing results in considerable environmental pollution and ecological consequences. Lignin, the second most abundant biomass source on earth, possesses attributes such as cost-effectiveness, renewability, biodegradability, and non-toxicity. Enriched with active functional groups including hydroxyl, carbonyl, carboxyl, and methyl, coupled with its rigid aromatic ring structure and inherent anti-oxidative and thermoplastic properties, lignin emerges as a promising candidate for formulating printable inks. This comprehensive review presents the utilization of lignin, either in conjunction with functional materials or through the modification of lignin derivatives, as the primary constituent (≥50 wt%) for formulating printable inks across photo-curing-based (SLA/DLP) and extrusion-based (DIW/FDM) printing technologies. Furthermore, lignin as an additive with multi-faceted roles/functions in 3D printing inks is explored. The effects of lignin on the properties of printing inks and printed objects are evaluated. Finally, this review outlines future perspectives, emphasizing key obstacles and potential opportunities for facilitating the high-value utilization of lignin in the realm of 3D printing.

Comprehensive repair of the alveolar cleft using cortical and cancellous bone layers: A retrospective study.

To retrospectively review the clinical effect of comprehensive treatment of alveolar cleft (CTAC) using the mandible as the bone source. Patients with alveolar clefts who met the inclusion criteria were subjected to a CTAC protocol that included the following: (1) preoperative orthodontic treatment for creating good soft-tissue conditions; (2) 'area-like grafting' with subperiosteal osteogenic chin bone instead of cartilaginous osteogenic iliac bone; (3) simulation of normal bone anatomy via a sandwich-like bone graft consisting of 'cortical bone + cancellous bone + cortical bone'; and (4) strong internal fixation to ensure initial bone block stability. At 6 months postoperatively, the titanium plate was removed and cone-beam computed tomography was performed to evaluate the surgical results. A total of 54 patients underwent treatment with the CTAC protocol. The average age at the initial operation was 10.3 ± 2.1 years, and the average hospital stay was 2.8 ± 0.6 days. At 6 months postoperatively, 49 patients (90.7%) showed good clinical results. The transplanted bone block formed a 'cortical bone + cancellous bone + cortical bone' structure similar to that of the normal jawbone. A mature bone bridge formed, and the impacted permanent teeth continued to erupt and enter the bone graft area. CTAC is a comprehensive restorative solution for alveolar cleft repair that integrates multiple concepts, including orthodontics, embryology, anatomy, and improvements to surgical methods. The method is easy to perform, causes little surgical trauma, and shows a stable success rate, and is thus worth promoting.

[Rapid prediction of surface roughness of natural polymer material by visible/near infrared spectroscopy as a non-contact measurement method].

In order to investigate the feasibility of visible/Near Infrared(Vis-NIR)spectroscopy to predict the surface roughness of natural polymer material(wood) as a non-contact measurement method, the correlations between Vis-NIR spectroscopy and surface roughness measured by contact(stylus) instruments from three different sections of wood samples were analyzed. The results showed that the surface roughness parameters, arithmetical mean deviation of profile (Ra), ten-point height of irregularities (Rz) and the maximum height of profile (Ry), of wood samples were successfully predicted by using Vis-NIR (400-2,500 nm) models from the three sections of the samples. The correlations between values measured by the stylus instruments and the values predicted by the models were good. The correlation coefficients of Rz reached up to 0.92. Compared to the models based on the Vis-NIR from the radial section and tangential section of the samples, the predictive effect of the model based on cross section was the best. The correlation coefficients between the values measured by the stylus instruments and the values predicted by the models based on different spectrum wavelength range, 400-780, 780-1,100, 1,100-2 500, 780-2,500 and 400-2,500 nm, were generally above 0.80. The prediction results of the model based on spectrum wavelength range 400-2,500 nm was better than the models based on the other spectrum wavelength ranges. The results showed that the predictive effect was not improved by pretreatment of the spectrum. It is proposed to use the original spectrum to predict the surface roughness of natural polymer material.

MFN1 augmentation prevents retinal degeneration in a Charcot-Marie-Tooth type 2A mouse model.

Charcot-Marie-Tooth disease type 2A (CMT2A), the most common inherited peripheral axonal neuropathy, is associated with more than 100 dominant mutations, including R94Q as the most abundant mutation in the Mitofusin2 (MFN2) gene. CMT2A is characterized by progressive motor and sensory loss, color-vision defects, and progressive loss of visual acuity. We used a well-established transgenic mouse model of CMT2A with R94Q mutation on MFN2 gene (MFN2 R94Q ) to investigate the functional and morphological changes in retina. We documented extensive vision loss due to photoreceptor degeneration, retinal ganglion cell and their axonal loss, retinal secondary neuronal and synaptic alternation, and Müller cell gliosis in the retina of MFN2 R94Q mice. Imbalanced MFN1/MFN2 ratio and dysregulated mitochondrial fusion/fission result in retinal degeneration via P62/LC3B-mediated mitophagy/autophagy in MFN2 R94Q mice. Finally, transgenic MFN1 augmentation (MFN2 R94Q :MFN1) rescued vision and retinal morphology to wild-type level via restoring homeostasis in mitochondrial MFN1/MFN2 ratio, fusion/fission cycle, and PINK1-dependent, Parkin-independent mitophagy.

Polydopamine modified cellulose nanocrystals (CNC) for efficient cellulase immobilization towards advanced bamboo fiber flexibility and tissue softness.

Herein, a green facile approach to improve the flexibility of unbleached bamboo kraft pulp (UBKP) via an immobilized enzyme technology is proposed. Polydopamine (PDA) acts as versatile modification and coating materials of cellulose nanocrystals (CNC) for assembling versatile bio-carriers (PDA@CNC). Cellulase biomacromolecules are efficiently immobilized on PDA@CNC to form cellulase@PDA@CNC nanocomposites. The relative enzyme activity, temperature/pH tolerance, and storage stability of cellulase were significantly improved after immobilization. The degree of polymerization treated UBKP decreased by 5.42 % (25 U/g pulp) compared to the control sample. The flexibility of treated fibers was 6.61 × 1014/(N·m2), which was 96.93 % higher (25 U/g) compared to the control and 3.88 times higher than that of the blank fibers. Cellulase@PDA@CNC performs excellent accessibility to fiber structure and induces high degree of fibrillation and hydrolysis of UBKP fibers, which contributes high softness of obtained tissue handsheets. The bio-carrier PDA@CNC within paper framework may further enhance tissue tensile strength. This study proposes a practical and environmentally friendly immobilization approach of cellulase@PDA@CNC for improving the hydrolysis efficiency and flexibility of UBKP fibers, which provides the possibility to maintain the strength of tissue paper while improving its softness, thus broadening the high-value application of immobilized enzyme technology in tissue production.

Adsorption of typical natural organic matter on microplastics in aqueous solution: Kinetics, isotherm, influence factors and mechanism.

With rapid urbanization, microplastics and natural organic matters (NOMs) are ubiquitous in aquatic environment, and microplastics could act as carriers for organic matters in the aqueous solution and may pose a potential risk. In this study, the adsorption behaviors and mechanism of typical NOM, humic acid (HA), on polyvinyl chloride (PVC) and polystyrene (PS) microplastics were investigated. Various influence factors such as solution pH, ions species and concentrations, particle size, and coexisting surfactants were studied. The results suggested that HA adsorption onto PVC and PS was low pH-dependent, and ion species and concentrations have a significant impact on the adsorption capacity. In addition, the particle size of PVC and PS microplastics exhibited a significant correlation with HA adsorption, and the adsorption process was influenced by the surfactant species and concentrations. Moreover, the adsorption behaviors of HA in different real water environments were tested, and UV aging exhibited the opposite effects on adsorption capacity of PVC and PS. Furthermore, the adsorption mechanisms of HA onto PVC and PS were explored, indicating halogen bonding, hydrogen bonding, and π-π interaction play important roles in the adsorption process.

Clinical application of 3D-printed PEEK implants for repairing mandibular defects.

The aim of this study was to investigate and discuss the efficacy of 3D-printed PEEK implants in personalized reconstruction of mandibular segmental defects. This study was a single-center case series. Six patients who underwent mandibular reconstruction with a custom-made 3D-printed PEEK implant were enrolled. Patient demographics, photographs, computed tomography (CT), and other clinical data were collected and analyzed pre- and postoperatively. The average patient age was 60.0 ± 15.09 years. The mean operative time was 213.33 ± 30.77 min, and the postoperative follow-up time ranged from 10 to 24 months. Mandibular segmental defects ranged from the symphysis to the condyle. Five patients did not have any postoperative complications and were satisfied with the cosmetic and functional results. One patient had to undergo removal of the PEEK implant because of implant exposure at 10 months after surgery. PEEK implants can repair different forms of defect in the mandible, maintaining the original shape of the mandible, whilst not affecting mandible functions, such as mastication and temporomandibular joint movement. However, PEEK implantation requires the strict selection of appropriate indications, especially with regard to the evaluation of soft-tissue conditions in the implanted area.

Biomechanical comparison of vertebral augmentation and cement discoplasty for the treatment of symptomatic Schmorl's node: a finite element analysis.

Percutaneous vertebral augmentation (PVA) and percutaneous cement discoplasty (PCD) are two relatively new minimally invasive surgeries for symptomatic Schmorl's reported in recent decade. However, the clinical evidence for the effectiveness of these two surgeries is insufficient. The purpose of this study was to compare the biomechanical benefits and risks of the two surgeries in order to analyze their biomechanical differences and effectiveness. We reconstructed Five lumbar finite element models via computed tomography data, including control model, PVA-ideal model, PVA-nonideal model, PCD-ideal model, and PCD-nonideal model. The stress and strain of Schmorl's nodes, bone marrow edema zone (BMEZ), affected endplate, and the overall stability of segment were analyzed and compared. The validity of our models was confirmed. As a result, the PVA-ideal model can significantly reduce the stress of Schmorl's node and the strain of BMEZ, while this effect is inappreciable in PVA-nonideal model. The PCD-ideal model significantly reduced the strain of Schmorl's nodes and BMEZ, and significantly improve segmental stability, but also resulted in a significant increase in the stress of Schmorl's nodes, BMEZ and endplates. The PCD-nonideal model not only lacks blocking effect, but also sharply increases the strain of Schmorl's nodes and BMEZ. Thus, We recommend that both PVA and PCD surgeries in ideal distribution facilitated a more stable paranodular biomechanical microenvironment. However, due to the possibility of poor biomechanical outcomes caused by the non-ideal cement distribution, the non-ideal distribution of bone cement needs to be remedied in practice.

Evaluation of an osteostimulative putty in the sheep spine.

The objective of this study is to evaluate local response to a bioactive glass based composite putty (NovaBone Putty) in a vertebral body defect model in sheep, as compared to NovaBone, a bioactive glass particulate. Two time periods were used for the study, 6 and 12 weeks. Empty defects were also used as a control. In comparing the three test groups, the relative amount of new bone for both grafted defects was substantially greater than for the empty controls (P < 0.05). At 6 weeks, the bone formation was 42% for NovaBone Putty, 27% for NovaBone and 1.2% for the ungrafted empty defect. At 12 weeks, the bone formation was 51.4% for NovaBone Putty, 47.3% for NovaBone and 5.1% for the empty defect. NovaBone Putty, the test material, had greater bone content than the NovaBone, both of which were significantly greater than the empty control.

In vitro measurement of the chemical changes occurring within ß-tricalcium phosphate bone graft substitutes.

Several mechanisms proposed to explain the osteoinductive potential of calcium phosphates involve surface mineralization ("bioactivity") and mention the occurrence of concentration gradients between the inner and the outer part of the implanted material. Determining the evolution of the local chemical environment occurring inside the pores of an implanted bone graft substitute (BGS) is therefore highly relevant. A quantitative and fast method was developed to measure the chemical changes occurring within the pores of ß-Tricalcium Phosphate (ß-TCP) granules incubated in a simulated body fluid. A factorial design of experiment was used to test the effect of particle size, specific surface area, microporosity, and purity of the ß-TCP granules. Large pH, calcium and phosphate concentration changes were observed inside the BGS and lasted for several days. The kinetics and magnitude of these changes (up to 2 pH units) largely depended on the processing and properties of the granules. Interestingly, processing parameters that increased the kinetics and magnitude of the local chemical changes are parameters considered to favor calcium phosphate osteoinduction, suggesting that the model might be useful to predict the osteoinductive potential of BGSs. STATEMENT OF SIGNIFICANCE: Recent results suggest that in situ mineralization of biomaterials (polymers, ceramics, metals) might be key in their ability to trigger ectopic bone formation. This is the reason why the effect on in situ mineralization of various synthesis parameters of ß-tricalcium phosphate granules was studied (size, microporosity, specific surface area, and Ca/P molar ratio). To the best of our knowledge, this is the first article devoted to the chemical changes occurring within the pores of a bone graft substitute. We believe that the manuscript will prove to be highly important in the design and mechanistic understanding of drug-free osteoinductive biomaterials.

3D-Printed Titanium Cage with PVA-Vancomycin Coating Prevents Surgical Site Infections (SSIs).

Many coating materials have been studied to prevent surgical site infections (SSIs). However, antibacterial coating on surfaces show weak adhesion using the traditional titanium (Ti) cage, resulting in low efficacy for preventing SSIs after spinal surgery. Herein, a 3D-printed Ti cage combined with a drug-releasing system is developed for in situ drug release and bacteria killing, leading to prevention of SSIs in vitro and in vivo. First, a 3D-printed Ti cage is designed and prepared by the Electron Beam Melting (EBM) method. Second, polyvinyl alcohol (PVA) containing hydrophilic vancomycin hydrochloride (VH) is scattered across the surface of 3D-printed porous Ti (Ti-VH@PVA) cages. Ti-VH@PVA cages show an efficient drug-releasing profile and excellent bactericidal effect for three common bacteria after more than seven days in vitro. In addition, Ti-VH@PVA cages exhibit reliable inhibition of inflammation associated with Staphylococcus aureus and effective bone regeneration capacity in a rabbit model of SSIs. The results indicate that Ti-VH@PVA cages have potential advantages for preventing SSIs after spinal surgery.

Down-regulation of osteopontin suppresses growth and metastasis of hepatocellular carcinoma via induction of apoptosis.

BACKGROUND & AIMS: Expression of osteopontin correlates with tumor progression and metastasis. The mechanisms by which osteopontin promotes tumor cell survival remain unclear. Here we used short-hairpin RNA-mediated gene silencing to investigate the antitumor effects by osteopontin depletion in hepatocellular carcinoma (HCC). METHODS: We applied polyethylenimine nanoparticles to deliver a short-hairpin RNA for depletion of osteopontin expression in HCC cells. Tumorigenicity and metastatic potentials of HCC cells were studied in vitro and in nude mice. Nuclear factor-kappaB (NF-kappaB) activation was analyzed by gel shift assay and luciferase analysis. The expressions of integrins were examined by real-time reverse-transcription polymerase chain reaction. Apoptosis was examined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay and mitochondrial membrane potential analysis. RESULTS: Down-regulation of osteopontin inhibited HCC cell growth, anchorage-independent growth, adhesion with fibronectin and invasion through extracellular matrix in vitro, and suppressed tumorigenicity and lung metastasis in nude mice. Osteopontin silencing resulted in suppression of alphav, beta1, and beta3 integrin expressions, blockade of NF-kappaB activation, inhibition of Bcl-2/Bcl-xL and XIAP expressions, increase of Bax expression, and induction of a mitochondria-mediated apoptosis. Furthermore, down-regulation of osteopontin inhibited drug-induced NF-kappaB activation and sensitized HCC cells to chemotherapeutic agents in vitro, which led to complete regression of HCC xenografts in nude mice. CONCLUSIONS: Osteopontin may facilitate tumorigenesis and metastasis through prevention of tumor cells from apoptosis. RNA interference-mediated depletion of osteopontin may be a promising strategy for the treatment of HCC by sensitizing the chemotherapeutic drugs.

Selective molecularly imprinted stationary phases for bisphenol A analysis prepared by modified precipitation polymerization.

Bisphenol A (BPA)-imprinted polymeric microspheres were synthesized by modified precipitation polymerization (MPP) method. Influences of cross-linker, monomer, porogen volume, and agitation on polymerization were investigated. Proper amount of cross-linker ethyleneglycol-dimethacrylate (EGDMA) was critical to achieve narrowly dispersed microspheres. For template BPA, monomer 4-vinylpyridine (4-VP) was better than MAA to get the best imprinted effects. The optimum template/monomer ratio was 1:6. Increasing porogen volume increased size dispersity and decreased binding characters. Agitation increased coagulation and resulted in irregular particles. Microspheres with the best binding characters were used as selective stationary phase of chromatographic column to detect BPA in milk, pig urine, and chicken meat. Under optimal chromatographic conditions, the calibration graph was linear with R2 = 0.9994 in the range of 3-50 micromol/L. The LOD and LOQ were 1 and 3 micromol/L, respectively. When large amounts (20 mL or 20 g) of samples were analyzed, the recoveries ranged from 70.2 to 87.3% with RSD less than 4.85% in all samples spiked with 0.05-0.2 micromol/L BPA. The intra-day and inter-day RSD were less than 1.83 and 3.96%, respectively. Microspheres prepared by MPP are successfully used in molecularly imprinted polymer (MIP)-based analytical column to detect trace BPA in different biologic samples with acceptable accuracy and repeatability.

Artificial atlanto-odontoid joint replacement through a transoral approach.

Resection of the odontoid process and anterior arch of the atlas results in atlantoaxial instability, which if left uncorrected may lead to severe neurological complications. Currently, such atlantoaxial instability is corrected by anterior and/or posterior C1-C2 fusion. However, this results in considerable loss of rotation function of the atlantoaxial complex. From the viewpoint of retaining the rotation function and providing stability, we designed an artificial atlanto-odontoid joint based on anatomical measurements of 50 pairs of dry atlantoaxial specimens by digital calipers and 10 fresh cadaveric specimens by microsurgical techniques. The metal-on-metal titanium alloy joint has an arc-shaped atlas component, and a hollow cylindrical bushing into which fits a rotation axle of an inverted v-shaped axis component and is implanted through a transoral approach. After the joint was implanted onto specimens with anterior decompression, biomechanical tests were performed to compare the stability parameters in the intact state, after decompression, after artificial joint replacement, and after fatigue test. Compared to the intact state, artificial joint replacement resulted in a significant decrease in the range of motion (ROM) and neutral zone (NZ) during flexion, extension, and lateral bending (P < 0.001); however, with regard to axial rotation, there was no significant difference in ROM (P = 0.405), a significant increase in NZ (P = 0.008), and a significant decrease in stiffness (P = 0.003). Compared to the decompressed state, artificial joint replacement resulted in a significantly decreased ROM (P B 0.021) and NZ (P B 0.002) and a significantly increased stiffness (P \ 0.001) in all directions. Following artificial joint replacement, there was no significant difference in ROM (P C 0.719), NZ (P C 0.580), and stiffness (P C 0.602) in all directions before and after the fatigue test. The artificial joint showed no signs of wear and tear after the fatigue test. This artificial atlanto-odontoid joint may be useful in cases of odontoid resection due to malunion or nonunion of odontoid fracture, atraumatic odontoid fracture, irreducible atlas dislocation, posterior atlantoaxial subluxation, or congenital skull base abnormalities.