Relationships between functional temporomandibular joint space and disc morphology, position, and condylar osseous condition in patients with temporomandibular disorder.

OBJECTIVE: To investigate the correlations between joint space and temporomandibular joint (TMJ) components and the compressive states of the disc and condyle subsequent to joint space changes. MATERIALS AND METHODS: A total of 240 TMJs were categorized according to disc morphology, disc position, and condylar osseous condition. The two-dimensional (2D) and three-dimensional (3D) measurements were compared. The functional joint space (FJS) and disc areas on closed- and open-mouth images (DA-C and DA-O) were also calculated, and the joint space was measured in five directions. Different groups of TMJ components were compared. A spring model was used to simulate the effect of condylar displacement on the disc and condyle. RESULTS: Disc morphology was strongly correlated with its position. The measurements were equivalent between 2D and 3D methods. DA-C and FJS differed significantly between groups. The DA-C to FJS ratio differed between the Class 2 and Class 3 groups and between disc displacement groups with and without reduction. Altered disc morphology and position were correlated with significant changes in joint space in the 60°, 90°, and 120° directions. Despite minor discrepancies among condylar osseous conditions, reduced joint space was correlated with bone destruction at the corresponding site. The spring model stimulation revealed that condylar displacement caused elevated stresses on the disc and condyle. CONCLUSIONS: Condylar displacement causes joint space alterations while exerting compressive pressure on both the disc and condyle. CLINICAL RELEVANCE: Proper condylar positioning within the fossa is recommended to ensure sufficient articular disc accommodation.

Three-dimensional theoretical model for effectively describing the effect of craniomaxillofacial structural factors on loading situation in the temporomandibular joint.

BACKGROUND: Temporomandibular joint (TMJ) overloading is considered a primary cause of temporomandibular joint disorders (TMD). Accordingly, craniomaxillofacial structural parameters affect the loading situation in the TMJ. However, no effective method exists for quantitatively measuring the loading variation in human TMJs. Clinical statistics, which draws from general rules from large amounts of clinical data, cannot entry for exploring the underlying biomechanical mechanism in craniomaxillofacial system. The finite element method (FEM) is an effective tool for analyze the stress and load on TMJs for several cases in a short period of time; however, it is difficult to generalize general patterns through calculations between different cases due to the different geometric characteristics and occlusal contacts between each case. METHODS: (1) This study included 88 subjects with 176 unilateral data to measure angle (α) of the distance to the plane of occlusion. The bone destruction score was evaluated for clinical statistics. To rule out effects of the potential factors and ensure the generality of the study, one participant with no obvious bone destruction was selected as the standard case for establishing the three-dimensional (3D) theoretical model and FEM. (2) Three groups of forces, including biting, muscles and joint reaction forces on mandible, were adopted to establish a 3D theoretical model. (3) By modifying the sagittal α and coronal three types of deviation angle (φ) of the original model, nine candidate models were obtained for the FEM studies. RESULTS: (1) The static equilibrium equations, were used to establish a 3D theoretical model for describing the loading of the TMJ. The theoretical model was validated by monotonously modifying the structural parameter in comparison to two-dimensional theoretical models reported previously; (2) The force on the TMJ gradually decreased with α, and this trend was validated by both clinic statistics and FEM results; (3) The effects of the three types of deviation angle were different. The results of the case where only rotating biting forces were considered was consistent with clinical statistics, indicating that the side with lower α experiences higher TMJ load. (4) Changing the unilateral proportionality coefficients of biting and muscle force produced opposite effects, wherein the effects of the muscle force were stronger than those of the biting forces. CONCLUSIONS: A negative correlation was observed between the joint load and α. Among the three types of asymmetric deformities, occlusal deviations were the primary factors leading to TMD. Unilateral occlusion can result in a greater load on the ipsilateral joint and should be avoided when using the side corresponding to the TMD. This study provides a theoretical basis for the biomechanical mechanism of TMD and also enables the targeted mitigation and treatment of TMD through structural modification.

Variation in stress distribution modified by mandibular material property: a 3D finite element analysis.

BACKGROUND: Temporomandibular joint disorder (TMD) is a common oral and maxillary facial disease. Finite element method (FEM) has been widely used in TMD studies. Material assignment significantly affects FEM results. The differences in the methods of material assignment used in previous studies have not been comprehensively assessed for further calculations. METHODS: The mandible material modelling approaches were of four types, namely: uniform modelling with (A) cortical bone; and (B) cancellous bone; (C) semi-uniform modelling with division of cortical and cancellous bone; and (D) non-uniform modelling with Computed tomography (CT) gray value related modulus. Meanwhile, the Young's modulus of values ranging from 20 to 300 GPa were considered for the teeth. Ten modellings were used to analyze and discuss the differences in contact pressure and contact force. RESULTS: (1) The increase in teeth elastic modulus increased the maximum contact pressure on the alveolar bone and contact force on teeth, but induced insignificant stress variation on the temporomandibular joint; (2) The location of the maximum contact pressure was steady for all four modelling approaches of the mandibular material. However, the maximum contact pressure and contact force exhibited an insignificant difference. CONCLUSIONS: Teeth with a higher elastic modulus significantly enhanced the stress concentration in the alveolar bone; in contrast, it induced minor variations in the temporomandibular joint stress states. The extreme stress regions predicted by the four mandibular models were consistent with the actual damaged regions. However, non-uniform modellings based on CT values could better describe the mechanical properties of the human bone, which should be primarily considered.

Borylative Cyclization of 1,6-Allenynes Driven by BCl3.

A metal-free intramolecular borylative cyclization of 1,6-allenynes driven by BCl3 was developed. This method provides a general and practical strategy to construct valuable pyrrolidines containing all-carbon quaternary centers or 3,5-dihydroazepine derivatives depending on the substituents of the allene, with conjugative and sterically hindered phenyl groups favoring the latter.

Surface-Enhanced Raman Scattering-Active Plasmonic Metal Nanoparticle-Persistent Luminescence Material Composite Films for Multiple Illegal Dye Detection.

Uniform two-dimensional plasmonic nanoparticle (NP)-semiconductor composite films could retard the attenuation of electromagnetic evanescent wave and show intensive Raman activity for the multiplex monitoring of hazards in a practical food matrix. Here, an efficient Raman platform is developed by employing a plasmonic nanoparticle (NP)-persistent luminescence material (PLM) composite film. PLM show upconversion photoluminescence (UCPL) properties. The emitted photons are absorbed by plasmonic NPs, which further boost the surface plasmon resonance for the generation of high polarizability and induce strong electromagnetic strength for surface-enhanced Raman scattering (SERS) enhancement. A UCPL-assisted SERS-enhanced mechanism is proposed and verified. A plasmonic NP-PLM film with superior SERS activity and detection capability becomes an alternative candidate for the sensitive and multiple detection of illegal addition of dyes in a food matrix. The proposed UCPL-assisted SERS-enhanced mechanism provides promising future directions to this end to design a next-generation SERS-active plasmonic NP-PLM composite film for the specific detection in complex samples.

Rational Design of Multisite Trielement Ru-Ni-Fe Alloy Nanocatalysts with Efficient and Durable Catalytic Hydrogenation Performances.

The co-decomposition of non-noble metals into Ru nanoparticles (NPs) would provide multiple active centers as well as synergistically alter the reaction pathway, enhancing the catalytic hydrogenation performance. Herein, a facile route for synthesizing trielement Ru-Ni-Fe alloy NPs was proposed. The catalytic hydrogenation performance of NPs was measured using p-nitrophenol as a model. The synergistic effect of these three elements (Ru, Ni, and Fe) and synergistic catalysis of multiple crystal faces greatly improved the catalytic hydrogenation performance of Ru44Ni28Fe28 alloy NPs. Ru with more vacant orbitals showed a strong coordination with BH4- for the generation of active H species. Ni played a major role in transporting electrons and active H species, increasing the accessibility of catalytically active sites. Fe could cooperate with BH4- to produce active H species and promote electrons transfer. Ru44Ni28Fe28 alloy NPs could be reused and applied for the fabrication of films at the oil-water (ethyl acetate-water) interface. The densely packed Ru44Ni28Fe28 NP films were good Raman substrates for monitoring the complete conversion of 4-nitrothiophenol into 4-aminothiophenol. The rational design of Ru44Ni28Fe28 will broaden the application range of Ru-based catalysts and provide new insights into the rational design of other multisite alloy catalysts.

Autoluminescence-Free Prostate-Specific Antigen Detection by Persistent Luminous Nanorods and Au@Ag@SiO2 Nanoparticles.

The sensitive detection of biomarker with high selectivity and accuracy is of remarkable significance for the early screening and clinical diagnosis of malignant cancer. Persistent phosphors play a role in illumination-free biosensing owing to their unparalleled optical properties, which produces long-lasting luminescence without the illumination to eliminate the interference of autofluorescence and scattering light from biological matrix. In this study, ZnGeO:Mo persistent luminescence nanorods (PLNRs) were prepared and showed tunable luminescence intensity and decay patterns. An excitation-free luminescent aptasensor was proposed for the detection of prostate specific antigen (PSA) by using ZnGeO:Mo PLNRs as probes and Au@Ag@SiO2 nanoparticles as quenchers. Under optimal conditions, the limit of detection for PSA was 9.2 pg mL-1. This work creates a possibility for the preparation of multiplex colored persistent luminescence nanomaterials with desired decay patterns for multiple bioassay and time-resolved fluoroimmunoassay.

Plasmonic Au-Ag Janus Nanoparticle Engineered Ratiometric Surface-Enhanced Raman Scattering Aptasensor for Ochratoxin A Detection.

Ochratoxin A (OTA), a toxic mycotoxin, poses severe risks to environment and human health. Herein, we develop a ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods for the sensitive and reproducible quantitative detection of OTA. Au-Ag Janus nanoparticles (NPs) are successfully synthesized under the guidance of 2-mercaptobenzoimidazole-5-carboxylic acid (MBIA), which possesses intrinsic Raman signals, thus no additional modification with a Raman reporter on NPs is required. In addition, Au-Ag Janus NPs exhibit amplified and stable SERS activity. MXenes nanosheets generate a unique and stable Raman signal, making them an ideal IS for quantitative Raman analysis. In principle, Au-Ag Janus NPs are assembled with MXenes nanosheets depending on hydrogen bond and the chelation interaction between MXenes nanosheets and OTA aptamers. In the presence of OTA, Au-Ag Janus NPs are dissociated from MXenes nanosheets due to the formation of aptamer/OTA complex, leading to the attenuation of Raman signal of Au-Ag Janus NPs, and meanwhile, the signal of MXenes nanosheets remain constant. Quantitatively, upon correction by the IS Raman signals, sensitive and quantitative detection can be achieved with the limit of detection (LOD) of 1.28 pM for OTA. Our results suggest that this ratiometric SERS aptasensor is a powerful tool which shows great promise for applications in complex systems.

Gap-Tethered Au@AgAu Raman Tags for the Ratiometric Detection of MC-LR.

Establishing a simple and accurate assay for detecting Microcystin-LR (MC-LR) is of significant important for the environment and human health. Herein, we develop a ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods for the sensitive and reproducible quantitative detection of MC-LR. Gap-tethered SERS-active Au@AgAu nanoparticles (NPs) are successfully prepared and the gap sizes are adjustable by simply adjusting the acidity. Gap-tethered Au@AgAu NPs exhibit gap-tunable amplified SERS activity and are served as SERS tags. The graphene oxide (GO)/Fe3O4 NPs demonstrate a unique and stable Raman band from the graphitic component, making them an ideal IS for quantitative Raman analysis. In principle, Au@gap@AgAu NPs are assembled with GO/Fe3O4 NPs depending on the π-π stacking interaction between GO and MC-LR aptamers. In the presence of MC-LR, Au@gap@AgAu NPs are dissociated from GO/Fe3O4 NPs due to the affinity of aptamer, leading to the changes of Raman intensity of SERS tags. Quantitatively, upon correction by the IS Raman signals, the limit of detection (LOD) is as low as 9.82 pM for MC-LR. The developed protocol provides a simple and rapid approach for the sensitive and quantitative detection of MC-LR and shows great promise for applications in complex systems.

Pt NPs catalyzed chemiluminescence method for Hg2+ detection based on a flow injection system.

Establishing a simple and accurate method for Hg2+ detection is of great importance for the environment and human health. In this work, platinum nanoparticles (Pt NPs) with different capped agents and morphologies were synthesized. It was found that Pt NPs exhibited peroxidase-like activity that can catalyze the chemiluminescence (CL) of the luminol system without H2 O2 . The most intensive CL signals were obtained by using PVP-capped Pt NPs as catalysis. Based on the fact that Hg2+ could further enhance the CL intensity in the Pt NPs-luminol CL system, a Pt NPs-catalyzed CL method based on a flow injection system is developed for the sensitive analysis of Hg2+ . When the concentration of Hg2+ in the system increases, the CL intensity would together increase, thereby achieving sensitive Hg2+ detection. The limit of detection (LOD) was calculated to be 8.6 nM. This developed method provides a simple and rapid approach for the sensitive detection of Hg2+ and shows great promise for applications in other complex systems.

Fluorometric nanoprobes for simultaneous aptamer-based detection of carcinoembryonic antigen and prostate specific antigen.

A "turn-on" fluorometric assay based on the combined effects of fluorescence resonance energy transfer (FRET) and internal filter effect (IFE) is described for the rapid and ultrasensitive detection of both carcinoembryonic antigen (CEA) and prostate specific antigen (PSA). Their unique porous structures and high specific surface enable mesoporous silica nanoparticles (MSNs) to load a large number of CdTe quantum dots (QDs). These amplify the fluorescence signal and provide a platform to fabricate more distinctly fluorescent MSNs (QD-MSNs). Two kinds of QD-MSNs with the maximum emission wavelengths at 590 nm (orange) and 731 nm (dark red) were fabricated and served as two types of fluorescent probes for the dual detection. Two aptamers were covalently connected to fluorescent MSNs as the recognition unit to warrant the selectivity of assay. The fluorescence of QD-MSNs can be quenched by molybdenum disulfide nanosheets (MoS2) due to FRET mechanism, IFE also contributed to the the reduction of fluorescence intensity. The fluorescence of QD-MSNs was further recovered in the presence of CEA and PSA attributing to the excellent specificity of aptamers. A "turn-on" fluorescent two-channel nanoprobe is introduced for simultaneous quantification of CEA and PSA. The respective limits of detection (at S/N = 3) are 0.7 fg•mL-1 for CEA and 0.9 fg•mL-1 for PSA. Graphical abstract Schematic presentation of the turn-on fluorescent nanoprobes for simultaneous detection of CEA and PSA.

Ag/CdO NP-Engineered Magnetic Electrochemical Aptasensor for Prostatic Specific Antigen Detection.

A simple magnetic electrochemical aptasensor was established for the detection of prostatic specific antigen (PSA). Ag/CdO nanoparticles (NPs) were fabricated and exhibited strong electroreduction peaks at -1.07 V, attributing to the electron transfer from Cd2+ to Cd0 and the superior electron transportation of Ag. Aptamer-modified Ag/CdO NPs were assembled on the surface of superparamagnetic Fe3O4/graphene oxide nanosheets (GO/Fe3O4 NSs) through the hydrophobic and π-π stacking interaction of aptamers and GO NSs. These assemblies possessed superior electroactive properties, efficient electron transfer, and superparamagnetic response and could serve as sensing units for PSA detection with the aid of a magnetic electrode. With increasing concentrations of PSA, the high affinity of aptamers to PSA enabled the dissociation of Ag/CdO NPs from GO/Fe3O4 NSs, decreasing the intensity of electroreduction peaks. The Ag/CdO NP-engineered magnetic electrochemical aptasensor achieved sensitive and accurate detection of PSA in the range of 50 pg/mL to 50 ng/mL. The limit of detection (LOD) was as low as 28 pg/mL. This developed protocol can be extended to a large set of strong electroactive labels for reliable tumor biomarker detection with high sensitivity and specificity.

Electroactive Au@Ag nanoparticles driven electrochemical sensor for endogenous H2S detection.

In this work, a novel and facile electrochemical sensor is reported for the highly selective and sensitive detection of dissolved hydrogen sulfide (H2S), attributing to the redox reaction between Au@Ag core-shell nanoparticles (Au@Ag NPs) and H2S. Electroactive Au@Ag NPs not only possess excellent conductivity, but exhibit great electrochemical reactivity at 0.26 V due to the electrochemical oxidation from Ag° to Ag+. In the presence of H2S, the Ag shell of Au@Ag NPs can be oxidized to Ag2S, resulting in the decrease of differential pulse voltammetry (DPV) peak at 0.26 V. The electrochemical sensor exhibits a wide linear response range from 0.1 nM to 500 nM. The limit of detection (LOD) for H2S is as low as 0.04 nM. The developed sensor shows significant prospects in the study of pathological processes related to the mechanism of H2S production.

Shell-encoded Au nanoparticles with tunable electroactivity for specific dual disease biomarkers detection.

The exploration of electroactive labelling with tailorable and strong differential pulse voltammetry (DPV) responses is of great importance in accurate and sensitive screening of a panel of biomarkers related to cancer. Herein, shell-encoded gold nanoparticles (Au NPs) are fabricated and give rise to shell species-dominated DPV peak potentials. Two independent DPV peaks appear at -0.08V for Au@Cu2O core-shell NPs and 0.26V for Au@Ag core-shell NPs. Shell-encoded Au NPs drastically exhibit shell thickness-tunable amplified peak currents. The non-interfering and amplified DPV responses enable shell-encoded Au NPs to be an alternative electrochemical signal amplifier for dual screening of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). The limits of detection (LODs) are calculated to be 1.8pg/mL for CEA and 0.3pg/mL for AFP. In comparison to the parallel single-analyte assays, shell-encoded Au NPs engineered electrochemical aptasensors offer multiplexing capability and show significant prospects in biomedical research and early diagnosis of diseases.