Application of lecture-and-team-based learning in stomatology: in-class and online.

BACKGROUND: This study aimed to evaluate stomatological students' learning efficacy and their attitude towards Lecture-Team-Based Learning (LTBL) on topics regarding the design of removable partial dentures via in-class, online, and both in combination. METHODS: Students from seven distinct grades participated in the course in their fourth academic year (Years 2015, 2016, 2017, 2018, 2019, 2020, and 2021). Students of Years 2015-2019 attended in-class LTBL, students of Year 2020 attended online LTBL, and students of Year 2021 attended the combination mode. The scores of three examinations were compared, namely, individual readiness assessment test, team readiness assurance test, and individual application test. Visual Analog Scales (VAS) were used for students to self-assess their mastery of prosthodontics knowledge before and after the course. Anonymous questionnaires were delivered to evaluate their satisfaction with LTBL via a Likert scale. RESULTS: In each academic year, the three exam scores were significantly improved as the course progressed and VAS-post scores were significantly higher than VAS-pre scores. The three examination and VAS scores of students in Year 2020 were significantly lower than those in Years 2019 and 2021. Students were highly satisfied with the LTBL course based on the three parameters of knowledge acquisition, teamwork, and classroom atmosphere. CONCLUSION: Students were highly satisfied with the LTBL course and their learning performance was improved as the course progressed both in-class and online. Online LTBL could be adopted when students have to study online, while in-class LTBL could perform better when combined with video records of an online LTBL course.

Comparative analysis of stress distribution in residual roots with different canal morphologies: evaluating CAD/CAM glass fiber and other post-core materials.

BACKGROUND: The selection of post-core material holds significant importance in endodontically treated teeth, influencing stress distribution in the dental structure after restoration. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) glass fiber post-core possesses a better adaptation for different root canal morphologies, but whether this results in a more favorable stress distribution has not been clearly established. MATERIALS AND METHODS: This study employed finite element analysis to establish three models of post-core crown restoration with normal, oversized, and dumbbell-shaped root canals. The three models were restored using three different materials: CAD/CAM glass fiber post-core (CGF), prefabricated glass fiber post and resin core (PGF), and cobalt-chromium integrated metal post-core (Co-Cr), followed by zirconia crown restoration. A static load was applied and the maximum equivalent von Mises stress, maximum principal stress, stress distribution plots, and the peak of maximum displacement were calculated for dentin, post-core, crown, and the cement acting as the interface between the post-core and the dentin. RESULTS: In dentin of three different root canal morphology, it was observed that PGF exhibited the lowest von Mises stresses, while Co-Cr exhibited the highest ones under a static load. CGF showed similar stress distribution to that of Co-Cr, but the stresses were more homogeneous and concentrated apically. In oversized and dumbbell-shaped root canal remnants, the equivalent von Mises stress in the cement layer using CGF was significantly lower than that of PGF. CONCLUSIONS: In oversized root canals and dumbbell-shaped root canals, CGF has shown good performance for restoration of endodontically treated teeth. CLINICAL RELEVANCE: This study provides a theoretical basis for clinicians to select post-core materials for residual roots with different root canal morphologies and should help to reduce the occurrence of complications such as root fracture and post-core debonding.

Critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages in periodontitis.

OBJECTIVE: To determine the critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages during periodontitis. BACKGROUND: Cathepsin S (CatS) is a cysteine protease and exerts important roles in the immune response. Elevated CatS has been found in the gingival tissues of periodontitis patients and is involved in alveolar bone destruction. However, the underlying mechanism of CatS-driven IL-6 production in periodontitis remains unclear. METHODS: Western blot was applied to measure mature cathepsin S(mCatS) and IL-6 expression in gingival tissues from periodontitis patients and RAW264.7 cells exposed to lipopolysaccharide from Porphyromonas gingivalis (P.g. LPS). Immunofluorescence was applied to confirm the localization of PU.1, and CatS in the gingival tissues of periodontitis patients. ELISA was performed to determine IL-6 production by the P.g. LPS-exposed RAW264.7 cells. Knockdown by shRNA was used to determine the effects of PU.1 on p38/ nuclear factor (NF)-κB activation, mCatS expression and IL-6 production in RAW264.7 cells. RESULTS: The expressions mCatS and IL-6 were significantly upregulated in gingival macrophages. In cultured RAW264.7 cells, increased mCatS and IL-6 protein paralleled the activation of p38 and NF-κB after exposure to P.g. LPS. CatS knockdown by shRNA significantly decreased P.g. LPS-induced IL-6 expression and p38/NF-κB activation. PU.1 was significantly increased in P.g. LPS-exposed RAW264.7 cells, and PU.1 knockdown dramatically abolished the P.g. LPS-induced upregulation of mCatS and IL-6 and the activation of p38 and NF-κB. Furthermore, PU.1 and CatS colocalized in macrophages within the gingival tissues of periodontitis patients. CONCLUSION: PU.1-dependent CatS drives IL-6 production in macrophages by activating p38 and NF-κB in periodontitis.

Effects of different custom-made mouthguard palatal extensions on the stress-state of dentoalveolar structures: a 3D-FEA.

OBJECTIVES: The present study aimed to simulate the influence of palatal extensions for custom-made mouthguards (MGs) on protecting dentoalveolar structures and to provide a theoretical basis for designing a comfortable MG. MATERIALS AND METHODS: Based on finite element analysis (3D-FEA), five groups of maxillary dentoalveolar models of wearing MGs were established: no MG on palatal side (NP), on palatal gingival margin (G0), 2 mm from the palatal gingival margin (G2), 4 mm from the palatal gingival margin (G4), 6 mm from the palatal gingival margin (G6), and 8 mm from the palatal gingival margin (G8). A cuboid was created to simulate the solid ground impacted in falls, a gradually increasing force was applied from 0 to 500 N on the vertical ground, and the distribution and peak values of the Critical modified von-Mises stress, maximum principal stress, and displacement of dentoalveolar models were calculated. RESULTS: Stress distribution range, stress, and deformation peak value of dentoalveolar models increased as the impact strength increased, at 500 N. Maximum critical modified von-Mises stress, peak maximum principal stress and maximum displacement of dentoalveolar models G4, G3, G2, G1, G0, and NP were 154.5 MPa, 154.5 MPa, 154.4 MPa, 154.7 MPa, 154.4 MPa, and 154.7 MPa; 191.65 MPa, 192.11 MPa, 191.62 MPa, 191.81 MPa, 191.56 MPa, and 191.62 MPa; and 88.78 µm, 88.57 µm, 88.19 µm, 88.67 µm, 88.43 µm, and 89.04 µ, respectively. However, the position of the MG palatal edge had little effect on stress distribution, stress, and deformation peak values of the dentoalveolar models. CONCLUSIONS: Different extension ranges of the MG palatal edge have little effect on the protective effects of MGs on maxillary teeth and maxilla. An MG with palatal extension on the gingival margin is more appropriate than other models and may help dentists to design a suitable MG and increase its usage. CLINICAL RELEVANCE: MGs with palatal extensions on the gingival margin may provide a more comfortable wearing experience for individuals involved in sports and encourage increased MG usage.

Biosynthesis of diverse α,ω-diol-derived polyhydroxyalkanoates by engineered Halomonas bluephagenesis.

Polyhydroxyalkanoates (PHA) are a family of biodegradable and biocompatible plastics with potential to replace petroleum based plastics. Diversity of PHA monomer structures provides flexibility in material properties to suit more applications. In this study, 5-hydroxyvalerate (5HV) synthesis pathway was established based on intrinsic alcohol/aldehyde dehydrogenases. The PHA polymerase cloned from Cupriavidus necator functions to polymerize 5HV into its copolymers in ratios ranging from 8% to 32%. Elastic copolymer P(85% 3HB-co-15% 5HV) was generated with an elongation at break and a Young's modulus of 1283% and 73.1 MPa, respectively. The recombinant H. bluephagenesis was able to convert various diols including 1, 3-propanediol, 1, 4-butanediol and 1, 5-pentanediol into PHA, leading to 13 PHA polymers including transparent P(53% 3HB-co-20% 4HB-co-27% 5HV) and sticky P(3HB-co-3HP-co-4HB-co-5HV). The engineered H. bluephagenesis was successfully grown in a 7-L bioreactor to produce the highly elastic P(85% 3HB-co-15% 5HV) and the sticky P(3HB-co-3HP-co-4HB-co-5HV), demonstrating their potential for industrial scale-up.

Rapid Quantification of Polyhydroxyalkanoates Accumulated in Living Cells Based on Green Fluorescence Protein-Labeled Phasins: The qPHA Method.

Polyhydroxyalkanoates (PHAs) are microbial polyesters that have the potential to replace nonbiodegradable petroplastics. A real-time in situ PHA quantification method has long been awaited to replace the traditional method, which is time- and labor-consuming. Quantification of PHA in living cells was finally developed from fluorescence intensities generated from the green fluorescence protein (GFP) fused with the Halomonas bluephagenesis phasin proteins. Phasins PhaP1 and PhaP2 were used to fuse with GFP, which reflected PHA accumulation with an R-square of over 0.9. Also, a standard correlation was established to calculate PHA contents based on the fluorescence and cell density recorded via a microplate reader with an R-square of over 0.95 when grown on various substrates. The PhaP2-GFP containing H. bluephagenesis was applied successfully to quantify PHA synthesis in a 7.5 L fermenter with high precision. Moreover, the method was found to be feasible in non-natural PHA producers such as Escherichia coli, demonstrating its broad applicability.

GSK3ß is involved in promoting Alzheimer's disease pathologies following chronic systemic exposure to Porphyromonas gingivalis lipopolysaccharide in amyloid precursor proteinNL-F/NL-F knock-in mice.

In line with the strong association between periodontitis and Alzheimer's disease (AD) clinically, preclinical studies have shown that systemic exposure to Porphyromonas gingivalis (Pg) initiates AD pathologies. However, the involvement of periodontitis in promoting AD pathologies is unclear. In the present study, we provided evidence that chronic systemic exposure to lipopolysaccharide derived from Pg (PgLPS, 1 mg/kg, daily, intraperitoneally) prompted neuroinflammation and tau hyperphosphorylation in 10-month-old of amyloid precursor protein (APP) knock-in mice, a model of AD, carrying the Swedish and Beyreuther/Iberian mutation (APPNL-F/NL-F). The learning and memory function were assessed using the passive avoidance test. The production of APP, Amyloid (A)ß1-42, cytokines, synaptic proteins and the activation of glycogen synthase kinase (GSK)-3ß as well as phosphorylation of tau were analyzed by immunohistochemistry, Western blotting or an enzyme-linked immunosorbent assay (ELISA) in the cortex of APPNL-F/NL-F mice. We found that systemic exposure of PgLPS for three consecutive weeks induced learning and memory deficits with significantly reduced postsynaptic density protein (PSD95). Increased hyperphosphorylation of tau in multiple residues, including Ser202, Thr231 and Ser396, but not the accumulation of Aß1-42 was detected in the neurons of APPNL-F/NL-F mice. Furthermore, PgLPS increased the GSK3ß activity by reducing its phosphorylation of the serine residue at position 9 (Ser9) and promoted neuroinflammation by increasing the expression of interleukin-1ß (IL-1ß) and tumor necrosis factor (TNF-α) while decreasing that of interleukin-10 (IL-10) and transforming growth factor (TGFß) in the cortex of APPNL-F/NL-F mice. Moreover, the PgLPS-increased GSK3ß activity was detected in both microglia and neurons, while the PgLPS-increased TNF-α expression was mainly detected in the microglia in the cortex of APPNL-F/NL-F mice. In in vitro studies, PgLPS (1 µg/ml) stimulation increased the mRNA and protein level of TNF-α in MG6 microglia, which were significantly inhibited by the GSK3ß-specific inhibitor TWS119. In contrast, the tau hyperphosphorylation and activation of GSK3ß in N2a neurons were enhanced after treatment with conditioned medium from PgLPS-stimulated microglia, which was attenuated after pre-treatment with TNF-α inhibitor. Taken together, these findings indicate that GSK3ß is involved in prompting microglia (TNF-α)-dependent tau hyperphosphorylation in neurons, resulting in learning and memory deficits in APPNL-F/NL-F mice without changes in the Aß expression during chronic systemic exposure to PgLPS. We propose that dampening GSK3ß activation may help delay the periodontitis-promoted pathological progression of AD.

Effects of 3 different residual root treatments after post-and-core restoration: An in vitro fracture resistance experiment and finite element analysis.

STATEMENT OF PROBLEM: Crown-lengthening procedures (CLPs) and orthodontic eruption procedures (OEPs) improve the biomechanical properties of residual root restoration. However, their use is limited by clinic time, cost, and crown-root ratio. An inner shoulder retention form (ISRF) overcomes these limits; however, whether ISRF meets the biomechanical requirements is unclear. PURPOSE: The purpose of this in vitro and finite element analysis (FEA) study was to evaluate the effects of 3 residual root treatments (ISRF, CLP, and OEP) on premolar fracture resistance and stress distribution after post-and-core restoration. MATERIAL AND METHODS: Thirty-two extracted mandibular second premolars were screened and randomly divided into 4 groups (n=8): a 2-mm ferrule restoration group (NPR2; control group) and 3 experimental groups (0.5×0.5-mm ISRF [ISRF0.5], 2-mm CLP [CLP2], and 2-mm OEP [OEP2]). After removal of the crown, endodontic treatment, and embedding and restoration, the specimens were loaded on a universal tester (crosshead speed of 0.1 mm per minute) at 30 degrees to the long axis of the tooth until fracture. Fracture resistance and pattern were analyzed. Four groups were added in FEA: 1-mm ferrule restoration group (NPR1), 1.0×1.0-mm ISRF (ISRF1), 1-mm CLP (CLP1), and 1-mm OEP (OEP1). The maximum principal stress peak (σmax), maximum displacement, and stress distribution were evaluated. RESULTS: Mean fracture load ±standard deviation was 796.23 ±155.61 N (NPR2), 650.32 ±150.43 N (ISRF0.5), 385.38 ±149.92 N (CLP2), and 542.93 ±79.34 N (OEP2); these differences were statistically significant (F=12.724; P<.001). The main fracture patterns were decementation from the lingual crown margin and oblique root fracture in ferrule restoration groups and post-and-core decementation and oblique fracture starting from the middle proximal surface in the ISRF groups without ferrules. In FEA, the results of NPR2, ISRF0.5, CLP2, and OEP2 were consistent with the in vitro experiments and provided stress distribution and displacement information. CONCLUSIONS: Teeth with crown dentin ferrules showed higher fracture resistance and lower stress concentration. For residual roots, ISRF and OEP showed no differences, but CLP had lower fracture resistance and higher stress concentration.

Ultrasensitive Fluorescence Lifetime Tuning in Patterned Polymer Composite Nanofibers with Plasmonic Nanostructures for Multiplexing.

Regulating fluorescence lifetime of lanthanide nanocomposites is highly desired for optical multiplexing applications, for instance, security printing, anticounterfeiting, and data storage. Herein, sensitive fluorescence lifetime tuning in nanocomposite fibers is reported which are composed of silica-coated gold nanorods assembled in Eu-polystyrene nanofibers. The prepared nanofibers possess unique properties of tunable fluorescence lifetime and distinct textured patterns together with superior flexibility and superhydrophobicity. In a single 612 nm emission channel, over ten different populations of fluorescence lifetime from the range of 322-551 µs are harvested. Thanks to the tunable fluorescence lifetime and different textured patterns, a security pattern to demonstrate optical multiplexing applications is designed. The security pattern hides the real information of "69" in a noticeable scene that shows fake information "8" under UV radiation or "13" by only watching their pattern structures.

Direct Cytosolic MicroRNA Detection Using Single-Layer Perfluorinated Tungsten Diselenide Nanoplatform.

Intracellular miRNA detection is vitally important for diagnosing severe diseases like cancer and for resolving the ensemble of gene products that orchestrate the living state of cells. Recent advances in the design, synthesis, and application of biocompatible nanomaterials as platforms for probing miRNAs have enabled widespread efforts to mobilize new compounds in biomedical research. Two-dimensional graphene-like nanomaterials exhibit desirable physical properties such as convenient quantum size and dynamic interface functionality. Because miRNAs regulate gene expression in the cytoplasm, it is imperative that nanomaterials targeting them are properly delivered. Unloading of nanomaterials into the cytosol using the cellular endocytic transport pathway is often hindered by an inability to cross the endosomal membrane. To address this challenge, we designed a strategy to deliver functionalized WSe2 nanosheets (FWNs) to the cytosol using perfluorinated surface functionalization. Perfluorinated compounds are both hydrophobic and lipophobic, exhibiting excellent phase-separation tendency in both polar and nonpolar environments. FWNs are ∼120 nm in diameter, feature low toxicity, and exhibit excellent stability in serum. The fluorinated nanostructure of FWNs enabled efficient cytosolic delivery from the endomembrane system. The fidelity of this approach was confirmed through intracellular delivery of two DNA probes (ssDNA-21 and ssDNA-210), which resulted in specific labeling of cytosolic miRNA and demonstrated the utility of this system for direct cytosolic biosensing.

Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: a three-dimensional finite element analysis.

OBJECTIVE: This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis. MATERIALS AND METHODS: Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. RESULTS: Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%. CONCLUSION: The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.

[Study on interface compatibility and fracture resistance of polyglycidyl methacrylate pre-impregnated quartz fiber reinforced polymethyl methacrylate denture base resin].

OBJECTIVE: To explore the reinforcement of polyglycidyl methacrylate (PGMA) pre-impregnated quartz fiber mesh in denture base materials by investigation of interface compatibility and fracture resistance. METHODS: 1-layer, 2-layer, 3-layer PGMA pre-impregnated quartz fiber meshes, electrolyzed cobalt-chromium alloy mesh and cobalt-chromium alloy mesh conditioned by metal primer were integrated in polymethyl methacrylate (PMMA) resin by sandwich embedding method. Block samples of 5 groups were prepared (40 mm×15 mm×2 mm). Fracture resistance was determined in a 3-point bending test at 2 mm/min. Scanning electron microscope (SEM), micrographs were taken from the fractured surfaces to analyze the bonding interface compatibility. RESULTS: The group of 3-layer PGMA pre-impregnated quartz fiber mesh presented the highest elastic modulus of 6 406 MPa and flexural strength of 227 MPa among the five groups, while the 1-layer and 2-layer expressed the similar elastic modulus and flexural strength to the pure PMMA group. The metal groups demonstrated better mechanical properties, while the metal surface conditioner played much better. The metal surface conditioner pre-impregnated cobalt-chromium alloy and PGMA pre-impregnated quartz fiber mesh showed compatible interface with PMMA. CONCLUSION: The mechanical properties were improved by the increasing of the fiber by adding the more meshed. Although the benign interface did help the compatibility, the quantity of the fibers played an important role in the strength.

Comparison of attitudes towards dental education among dental students in Japan and China.

The aim of this study was to identify and compare the attitudes of dental students towards dental education in Japan and China. Fifty-four dental students from the Stomatology School of China Medical University and 51 dental students from the Dental Faculty of Kyushu University, Japan, participated in this study. Information was derived from a self-answered questionnaire consisting of 11 items. Significant differences in the responses of the participants from the two countries were detected for 10 of the questionnaire items (P < 0.05). Nearly three-quarters of the Japanese students were satisfied with the teaching faculties of their schools, while only a quarter of the Chinese students indicated satisfaction. A total of 69% of Chinese students thought that learning a foreign language wasted too much time compared with none of the Japanese students. A student-oriented teaching mode was not well accepted by either of the groups, and 62% of Chinese students and 53% of Japanese students wanted to increase the duration of the clinical practice stage of education. The findings from this study enhance our understanding of differences and/or similarities among dental students in the two nations. This information may help to define strategies to improve the quality of dental education, and especially exchange programmes of international students.

Career choice and future design of dental students in China and Japan.

The purpose of this study was to compare career choice and future plans of dental students in China and Japan. Information was derived from a self-answered questionnaire. Significant differences were detected for eight items between the two countries. Regarding motivation towards career choice, 41% of Japanese students indicated positive motives related to helping others, achieving self-worth and health-care related interests, whereas Chinese students indicated that their choice was mainly for financial and prestige reasons, and for 32% of them, dentistry was a passive choice. More Chinese dental students (74%) wanted further education compared with Japanese students (22%). The majority of Japanese students (56.9%) planned to work as general dentists. Conversely, Chinese students were more likely to specialise (50%). More than 50% of Japanese students wanted to work in dental offices, but the majority of Chinese students (65%) preferred university hospital. We found it is strange that nearly one-fourth of the Chinese students did not want to be a clinical dentist mainly because of the poor health-care environment. This study provides a description of the perspectives of Japanese and Chinese dental students and enables a better understanding of career choices and future course design issues.

PHA is not just a bioplastic!

Polyhydroxyalkanoates (PHA) have evolved into versatile biopolymers, transcending their origins as mere bioplastics. This extensive review delves into the multifaceted landscape of PHA applications, shedding light on the diverse industries that have harnessed their potential. PHA has proven to be an invaluable eco-conscious option for packaging materials, finding use in films foams, paper coatings and even straws. In the textile industry, PHA offers a sustainable alternative, while its application as a carbon source for denitrification in wastewater treatment showcases its versatility in environmental remediation. In addition, PHA has made notable contributions to the medical and consumer sectors, with various roles ranging from 3D printing, tissue engineering implants, and cell growth matrices to drug delivery carriers, and cosmetic products. Through metabolic engineering efforts, PHA can be fine-tuned to align with the specific requirements of each industry, enabling the customization of material properties such as ductility, elasticity, thermal conductivity, and transparency. To unleash PHA's full potential, bridging the gap between research and commercial viability is paramount. Successful PHA production scale-up hinges on establishing direct supply chains to specific application domains, including packaging, food and beverage materials, medical devices, and agriculture. This review underscores that PHA's future rests on ongoing exploration across these industries and more, paving the way for PHA to supplant conventional plastics and foster a circular economy.

Bio(sensors) based on molecularly imprinted polymers and silica materials used for food safety and biomedical analysis: Recent trends and future prospects.

In recent decades, analytical techniques have increasingly focused on the precise quantification. Achieving this goal has been accomplished with conventional analytical approaches that typically require extensive pretreatment methods, significant reagent usage, and expensive instruments. The need for rapid, simple, and highly selective identification platforms has become increasingly pronounced. Molecularly imprinted polymer (MIP) has emerged as a promising avenue for developing advanced sensors that can potentially surpass the limitations of conventional detection methods. In recent years, the application of MIP-silica materials-based sensors has garnered significant attention owing to their distinctive characteristics. These types of probes hold a distinct advantage in their remarkable stability and durability, all of which provide a suitable sensing platform in severe environments. Moreover, the substrate composed of silica materials offers a vast surface area for binding, thereby facilitating the efficient detection of even minuscule concentrations of targets. As a result, sensors based on MIP-silica materials have the potential to be widely applied in various industries, including medical diagnosis, and food safety. In the present review, we have conducted an in-depth analysis of the latest research developments in the field of MIPs-silica materials based sensors, with a focus on succinctly summarizing and elucidating the most crucial findings. This is the first comprehensive review of integration MIPs with silica materials in electrochemical (EC) and optical probes for biomedical analysis and food safety.

Finite element analysis of endodontically treated premolars without ferrule restored with one-piece glass fiber post and core in combination with different inner shoulder retention form systems.

OBJECTIVE: The current study was performed to explore the impact of post materials as well as the inner shoulder retention form (ISRF) design on the biomechanical behavior of endodontically treated premolars without ferrule restoration using a method of mathematical three-dimensional (3D) finite element analysis (FEA). METHODS: Based on the tooth anatomy and our previous research, eight mandibular second premolar FEA models representing different restorative situations were built: teeth with (a) 2.0 mm height ferrule (DF), (b) no ferrule (NF), (c) 0.5 mm width and 0.5 mm depth ISRF (ISRFW0.5D0.5), (d) 0.5 mm width and 1.0 mm depth ISRF (ISRFW0.5D1.0), (e) 0.5 mm width and 1.5 mm depth ISRF (ISRFW0.5D1.5), (f) 1.0 mm width and 0.5 mm depth ISRF (ISRFW1.0D0.5), (g) 1.0 mm width and 1.0 mm depth ISRF (ISRFW1.0D1.0), (h) 1.0 mm width and 1.5 mm depth ISRF (ISRFW1.0D1.5). All groups were restored with prefabricated glass fiber post and resin composite core (PGF), one-piece glass fiber post-and-core (OGF) and cast Co-Cr alloy (Co-Cr) respectively, and the zirconia crown was restored. Load (180N) was subjected to the buccal cusp at 45° to the tooth's long axis. Stress pattern, maximum principal stress values (MPS), and maximum displacement values on root, post and core, cement layer were calculated for each model. RESULTS: Stress distributions were similar while the values were different among groups. Regardless of restorative approaches, roots restored with PGF showed the highest MPS values, followed by OGF and Co-Cr groups. Regardless of post materials, NF groups resulted in the highest MPS values and maximum displacement values, while ISRF and DF groups exhibited similar results. Compared with PGF groups in association with ISRF, except for OGF with ISRFW0.5D0.5, the remaining OGF groups with ISRF and all Co-Cr groups in association with ISRF presented lower values than that of DF groups. And among different ISRF systems, roots restored with ISRFW1.0D1.0 presented the lowest stress (PGF: 32.96 MPa, OGF: 31.69 MPa, Co-Cr: 29.66 MPa). CONCLUSIONS: For endodontically treated premolars without ferrule, restored with OGF in combination with ISRF preparation could effectively enhanced its load-bearing capacity. Furthermore, the ISRF with a depth and width of 1.0 mm is recommended.

Microchip gas chromatography column using magnetic beads coated with polydimethylsiloxane and metal organic frameworks.

Micro gas chromatography (µGC) using microfabricated silicon columns has been developed in response to the requirement for portable on-site gas analysis. Although different stationary phases have been developed, repeatable and reliable surface coatings in these rather small microcolumns remains a challenge. Herein, a new stationary phase coating strategy using magnetic beads (MBs) as carriers for micro column is presented. MBs modified with organopolysiloxane (MBs@OV-1) and a metal organic framework (MBs@HKUST-1) are deposited in on-chip microcolumns assisted with a magnetic field with an optimized modification process. MBs@OV-1 column showed a minimum HETP of 0.074 cm (1351 plates/m) of 62 cm/s. Mixtures of volatile organic compounds are successfully separated using MBs carried stationary phase which demonstrates that this technique has good chromatographic column efficiency. This method not only provides a novel coating process, washing and characterization of the stationary phases but also establishes a straightforward strategy for testing new absorbent materials for µGC systems.

Formation and characterization of konjac glucomannan/ethyl cellulose films by using ethanol and water as the solvents.

Hydrophilic konjac glucomannan (KGM)/hydrophobic ethyl cellulose (EC) film was prepared in the ethanol/water environment. The film-forming solution and film properties were both characterized to analyze the molecular interaction changes. Although higher ethanol usage enhanced the stability of the film-forming solution, it did not benefit the film property improvement. The SEM images showed some fibrous structure on the air surface of the films, consistent with the XRD results. The changing trend of mechanical properties and the FTIR results suggested that both ethanol content and ethanol evaporation impacted the molecular interaction during the film formation. The surface hydrophobicity results indicated that the ethanol content could cause significant EC aggregation changes on the film surface only with high EC contents. The water vapor permeability results suggested that higher ethanol usage decreased the compactness of the films. Considering all results, the 20 % ethanol content and the weight ratio of KGM: EC = 7:3 were suggested for the film preparation due to the superior properties in most properties. This study contributed to the understanding of polysaccharide interaction in the ethanol/water environment and offered an alternative biodegradable packaging film.

[Neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease : clinical features, MRI findings and follow-up study].

OBJECTIVE: To explore the clinical and magnetic resonance imaging (MRI) characteristics and the follow-up outcomes of neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease. METHODS: The clinical and MRI manifestations and follow-up outcomes in 35 children, at Second Affiliated Hospital, Wenzhou Medical College from August 2008 to November 2010, hospitalized with neurologic complications of enterovirus 71-infected hand-foot-mouth disease were retrospectively analyzed. RESULTS: Six children with aseptic meningitis presented the clinical symptoms and signs of meningitis. Five of them showed subdural effusion and ventriculomegaly, or both on MRI. At follow-ups, neurologic sequel could not be found. Among 24 cases with brainstem encephalitis, there were myoclonic jerks and tremor, ataxia, or both (grade I disease, n = 12), myoclonus and cranial-nerve involvement (grade II disease, n = 4), and cardiopulmonary failure after brain-stem infection (grade III disease, n = 8). In patients with brainstem encephalitis, lesions were predominantly located at the posterior portions of medulla and pons with hypointensity on T1WI and hyperintensity on T2WI. Cerebellar dentate nucleus, caudate nucleus and lenticular nucleus could also be involved. At follow-ups, the patients with mild symptoms had no neurologic sequel and the lesions within brain stem became small or vanished in most cases. While in the majority of serious patients, neurologic sequel could be found and the lesions located at brain stem became encephalomalacia. Fourteen cases with acute flaccid paralysis presented acute limb myasthenia with tendon reflex and muscular tension decreased. On spinal MRI, the lesions predominantly involved anterior horn regions of spinal cord with hypointensity on T1WI and hyperintensity on T2WI. Most patients improved their muscle strength and most lesions of spinal cord became smaller or vanished during follow-ups. CONCLUSION: MRI is the most effective modality of diagnosis and follow-up for neurologic complications in children with enterovirus 71-infected hand-foot-mouth disease. On MRI, the lesions mainly involve the anterior horn of spinal cord, medulla oblongata and pons. At follow-ups, most patients have no neurologic sequel and the visualized lesions will be absorbed after active treatment.