Application of virtual reality and haptics system Simodont in Chinese dental education: A scoping review.

INTRODUCTION: Virtual reality (VR) and haptic simulation technology have been increasingly implemented in dental training. Since the first haptic VR dental simulator (Simodont) was introduced 10 years ago, it has been applied in more than 40 universities in mainland China. This scoping review aimed to review literature, showcasing the teaching reform of dental virtual simulation in mainland China to global dental education peers. METHODS: This scoping review was conducted using the PRISMA extension for scoping review guidelines. Seven electronic databases were searched, and two reviewers independently performed the selection and characterization of the studies. RESULTS: The final scoping review included 12 studies. Four studies focused on the G. V. Black class II cavity, three on manual dexterity skills training, two on full metal crown preparation, one on pulpal access and coronal cavity preparation, one on flipped classroom teaching, and one on 'doctor-patient communication' skills. DISCUSSION: The most critical scenarios, self-assessment, working posture, curriculum setting, training and cost are analysed and discussed. CONCLUSION: Haptic simulation technology is a valuable complementary tool to the phantom head in dental education. The combined utilization of these two training devices has been superior to either in isolation. However, there is a lack of research on the sequencing of the two systems, as well as the appropriate distribution of curriculum between them. It is necessary for educators to organize or engage in experience sharing, collaboration and knowledge dissemination. These actions are essential for promoting effective teaching within dental educational institutions.

Topotactic Growth of Free-Standing Two-Dimensional Perovskite Niobates with Low Symmetry Phase.

Here, we report a novel topotactic method to grow 2D free-standing perovskite using KNbO3 (KN) as a model system. Perovskite KN with monoclinic phase, distorted by as large as ∼6 degrees compared with orthorhombic KN, is obtained from 2D KNbO2 after oxygen-assisted annealing at relatively low temperature (530 °C). Piezoresponse force microscopy (PFM) measurements confirm that the 2D KN sheets show strong spontaneous polarization (Ps) along [101̅]pc direction and a weak in-plane polarization, which is consistent with theoretical predictions. Thickness-dependent stripe domains, with increased surface displacement and PFM phase changes, are observed along the monoclinic tilt direction, indicating the preserved strain in KN induces the variation of nanoscale ferroelectric properties. 2D perovskite KN with low symmetry phase stable at room temperature will provide new opportunities in the exploration of nanoscale information storage devices and better understanding of ferroelectric/ferroelastic phenomena in 2D perovskite oxides.

Interface Chelation Induced by Pyridine-Based Polymer for Efficient and Durable Air-Processed Perovskite Solar Cells.

Polymer doping is a significant approach to precisely control nucleation and crystal growth of perovskites and enhance electronic quality in perovskite solar cells (PSC) prepared in air. Here, a brand-new self-healing polysiloxane (SHP) with dynamic 2,6-pyridinedicarboxamide (PDCA) coordination units and plenty of hydrogen bonds was designed and incorporated into perovskite films. PDCA units, showing strong intermolecular Pb2+ -Namido , I- -Npyridyl , and Pb2+ -Oamido coordination interactions, were expected to enhance crystallinity and passivate the grain boundary. In addition, abundant hydrogen bonds in SHP afforded the self-healing of cracks at grain boundaries for fatigue PSCs. Significantly, the doped device demonstrated a champion efficiency of 19.50 % with inconspicuous hysteresis, almost rivaling those achieved in control atmosphere. This strategy of heterocyclic-based macromolecular doping in PSCs will pave a way for realizing efficient and durable crystalline semiconductors.

Nanographene with Multiple Embedded Heptagons: Cascade Radical Photocyclization.

Although heptagons are widely found in graphenic materials, the precise synthesis of nanocarbons containing heptagons remains a challenge, especially for the nanocarbons containing multiple-heptagons. Herein, we show that photo-induced radical cyclization (PIRC) can be used to synthesize multi-heptagon-embedded nanocarbons. Notably, a nanographene containing six heptagons (1) was obtained via a six-fold cascade PIRC reaction. The structure of 1 was clearly validated and showed a Monkey-saddle-shaped conformation. Experimental bond analysis and theoretical calculations indicated that the heptagons in 1 were non-aromatic, whereas the peripheral rings were highly aromatic. Compared to planar nanographene with the same number of π electrons, 1 had a similar optical gap due to a compromise between the decreased conjugation in the wrapped structure and enhanced electronic delocalization at the rim. Electrochemical studies showed that 1 had low-lying oxidation potentials, which was attributed to the nitrogen-doping.

Prognostic Significance of Pretreatment Prognostic Nutritional Index (PNI) in Patients with Nasopharyngeal Carcinoma: A Meta-Analysis.

OBJECTIVE: Previous studies have investigated the pretreatment prognostic nutritional index (PNI) as a prognostic factor in patients with nasopharyngeal carcinoma (NPC); however, the results remained inconsistent. We aimed to assess the prognostic value of PNI in patients with NPC through conducting meta-analysis. Methods: Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for low PNI of overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), loco-regional recurrence-free survival (LRFS), and cancer-specific survival (CSS). Results: Totally, eight studies involving 4299 patients were included in this meta-analysis. A low pretreatment PNI was associated with poor OS (HR = 1.86, 95% CI = 1.55-2.33, P < 0.001), DMFS (HR = 2.03, 95% CI = 1.69-2.44, P < 0.001), PFS (HR = 1.57, 95% CI = 1.31-1.90, P < 0.001), and CSS (HR = 2.29, 95% CI = 1.54-3.42, P < 0.001). The subgroup analysis showed that low PNI remained a significant factor for poor OS, DMFS, and PFS irrespective of treatment, country, and cutoff value of PNI. In addition, low PNI was correlated to female gender (OR = 1.35, 95% CI = 1.12-1.62, P = 0.002), older age (OR = 1.75, 95% CI = 1.17-2.62, P = 0.007), and T3-T4 stage (OR = 1.27, 95% CI = 1.06-1.53, P = 0.011). Conclusions: A low PNI was associated with poor survival outcomes in patients with NPC. Moreover, PNI could serve as an index to help guide clinical management for older patients.

In vitro single-cell dissection revealing the interior structure of cable bacteria.

Filamentous Desulfobulbaceae bacteria were recently discovered as long-range transporters of electrons from sulfide to oxygen in marine sediments. The long-range electron transfer through these cable bacteria has created considerable interests, but it has also raised many questions, such as what structural basis will be required to enable micrometer-sized cells to build into centimeter-long continuous filaments? Here we dissected cable bacteria cells in vitro by atomic force microscopy and further explored the interior, which is normally hidden behind the outer membrane. Using nanoscale topographical and mechanical maps, different types of bacterial cell-cell junctions and strings along the cable length were identified. More important, these strings were found to be continuous along the bacterial cells passing through the cell-cell junctions. This indicates that the strings serve an important function in maintaining integrity of individual cable bacteria cells as a united filament. Furthermore, ridges in the outer membrane are found to envelop the individual strings at cell-cell junctions, and they are proposed to strengthen the junctions. Finally, we propose a model for the division and growth of the cable bacteria, which illustrate the possible structural requirements for the formation of centimeter-length filaments in the recently discovered cable bacteria.

Surface Permeability of Membrane and Catalytic Performance Based on Redox-Responsive of Hybrid Hollow Polymeric Microcapsules.

"Smart" polymeric microcapsules with excellent permeability of membranes have drawn considerable attention in scientific and industrial research such as drug delivery carriers, microreactors, and artificial organelles. In this work, hybrid hollow polymeric microcapsules (HPs) containing redox-active gold-sulfide bond were prepared with bovine serum albumin, inorganic metal cluster (AuNCs), and poly(N-isopropylacrylamide) conjugates by using Pickering emulsion method. HPs were transferred from water-in-oil to water-in-water by adding PEGbis(N-succinimidylsuccinate). To achieve redox-responsive membrane, the Au-S bond units incorporated into the microcapsules' membranes, allowed us to explore the effects of a new stimuli, that is, the redox Au-S bond breaking on the microcapsules' membranes. The permeability of these hybrid hollow polymeric microcapsules could be sensitively tuned via adding environment-friendly hydrogen peroxide (H2O2), resulting from a fast fracture of Au-S bond. Meanwhile, AuNCs and conjugates could depart from the microcapsules, and enhance the permeability of the membrane. Based on the excellent permeability of the membrane, phosphatase was encapsuled into HPs and p-nitrophenyl phosphate as a substrate. After adding 1 × 10-2 and 1 × 10-4 M H2O2, the catalytic efficiency was nearly 4.06 and 2.22 times higher than that of HPs in the absence of H2O2, respectively. Hence, the unique redox-responsive HPs have potential applications in biocatalytic reaction, drug delivery, and materials as well as in bioscience.

Autonomic Behaviors in Lipase-Active Oil Droplets.

Developing self-fueled micro-reactor droplets with programmable autonomic behaviors provides a step towards smart liquid dispersions comprising motile microscale objects. Herein, we prepare aqueous suspensions of lipase-coated oil globules comprising a mixture of a triglyceride substrate (tributyrin, 1,2,3-tributylglycerol) and a low-density oil (polydimethylsiloxane, PDMS) and describe a range of active behaviors based on controlled enzyme-mediated consumption of individual droplets under non-equilibrium conditions. Encapsulation of the lipase-coated lipid/PDMS droplets into a model protocell as energy-rich sub-compartments is demonstrated as an internalized mechanism for activating protocell buoyancy. Taken together, our results highlight opportunities for the regulation of autonomic behavior in enzyme-powered oil droplets and provide a new platform for increasing the functionality and energization of synthetic protocells.

High-Contrast SEM Imaging of Supported Few-Layer Graphene for Differentiating Distinct Layers and Resolving Fine Features: There is Plenty of Room at the Bottom.

For supported graphene, reliable differentiation and clear visualization of distinct graphene layers and fine features such as wrinkles are essential for revealing the structure-property relationships for graphene and graphene-based devices. Scanning electron microscopy (SEM) has been frequently used for this purpose where high-quality image contrast is critical. However, it is surprising that the effect of key imaging parameters on the image contrast has been seriously undermined by the graphene community. Here, superior image contrast of secondary electron (SE) images for few-layer graphene supported on SiC and SiO2 /Si is realized through simultaneously tuning two key parameters-acceleration voltage (Vacc ) and working distance (WD). The overlooked role of WD in characterizing graphene is highlighted and clearly demonstrated. A unified model of Vacc and WD dependence of three types of SE collected by the standard side-attached Everhart-Thornley (E-T) SE detector is conceptually developed for mechanistically understanding the improved mass thickness contrast for supported few-layer graphene. The findings reported here will have important implications for effective characterizations of atomically thick 2D materials and devices.

Light triggered interfacial damage self-healing of poly(p-phenylene benzobisoxazole) fiber composites.

The interfacial microcracks in the resin matrix composites are difficult to be detected and repaired. However, the self-healing concept provides opportunities to fabricate composites with unusual properties. In the present study, photothermal conversion Ag-Cu2S nanoparticles were immobilized onto poly(p-phenylene benzobisoxazole) (PBO) fibers via a polydopamine chemistry. Benefitting from the photothermal effects of Ag-Cu2S, the obtained PBO fibers (Ag-Cu2S-PBO) efficiently converted the light energy into heat under Xenon lamp irradiation. Then, single PBO fiber composites were prepared using thermoplastic polyurethane as the matrix. It was found that the interfacial damage caused by single fiber pull-out was simply self-healed by Xe light irradiation. This wonderful interfacial damage self-healing property was mainly attributed to the in situ heating generation via photothermal effects of Ag-Cu2S in the composite interface. This paper reports a novel strategy to construct advanced composites with light-triggered self-healing properties, which will provide inspiration for preparing high performance composite materials.

Coordinated Membrane Fusion of Proteinosomes by Contact-Induced Hydrogel Self-Healing.

Controlled membrane fusion of proteinosome-based protocells is achieved via a hydrogel-mediated process involving dynamic covalent binding, self-healing, and membrane reconfiguration at the contact interface. The rate of proteinosome fusion is dependent on dynamic Schiff base covalent interchange, and is accelerated in the presence of encapsulated glucose oxidase and glucose, or inhibited with cinnamyl aldehyde due to enzyme-mediated decreases in pH or competitive covalent binding, respectively. The coordinated fusion of the proteinosomes leads to the concomitant transportation and redistribution of entrapped payloads such as DNA and dextran. Silica colloids with amino-functionalized surfaces undergo partial fusion with the proteinosomes via a similar dynamic hydrogel-mediated mechanism. Overall, the strategy provides opportunities for the development of interacting colloidal objects, control of collective behavior in soft matter microcompartmentalized systems, and increased complexity in synthetic protocell communities.

Laparoscopic surgery after neoadjuvant therapy in elderly patients with rectal cancer.

PURPOSE: The standard treatment for mid or low locally advanced rectal cancer is neoadjuvant therapy followed by surgical resection. Laparoscopic surgery has recently been applied for the treatment of rectal cancer. However, few studies have reported the outcomes of laparoscopic surgery for elderly patients with rectal cancer after neoadjuvant therapy. This study aimed to investigate the short- and long-term outcomes of laparoscopic surgery for elderly patients with rectal cancer after neoadjuvant therapy. METHODS: Patients received a total dose of 50.4 Gy over 5.5 weeks (45 Gy in 25 fractions to the pelvid and 5.4 Gy boost in 3 fractions to the primary tumor). Laparoscopic surgery for rectal cancer after neoadjuvant therapy was performed at our hospital on 89 elderly patients aged 75 years or older (the elderly group) from January 2008 to January 2016. Outcomes of the 89 patients were compared to those of 269 patients younger than 75 years enrolled during the same time period (the nonelderly group). RESULTS: Compared with the nonelderly group, the Charlson comorbidity index (CCI) and American Society of Anesthesiologists (ASA) scores were higher in the elderly group. For short-term outcomes, there were no statistically significant differences. Differences between the two groups in the 5-year overall survival (OS) rate and 5-year disease-free survival (DFS) rate were not statistically significant. CONCLUSION: Although the CCI was higher in elderly patients than in the nonelderly patients, laparoscopic surgery after neoadjuvant therapy was safe and effective in elderly patients with rectal cancer. Therefore, in the absence of any contraindications, laparoscopic surgery after neoadjuvant therapy is an appropriate treatment approach for elderly patients with rectal cancer.

Fabrication of light, flexible and multifunctional graphene nanoribbon fibers via a 3D solution printing method.

Graphene oxide nanoribbons (GONRs) are one of the most promising carbon based materials. The integration of 2D GONR sheets into macroscopic materials, such as continuous fibers or film, leads the way in translating the good properties of individual GONR sheets into macroscopic and ordered materials for future applications. In this study, we first report the fabrication of GONR fibers utilizing GONR sheets as the raw material without any supporting surfactant or polymer. The method of fabricating fibers is referred to as '3D solution printing'. GONR fibers exhibit good mechanical and electrical properties, whose tensile strength and electrical conductivity could reach up to 95 MPa and 680 S cm-1, respectively. Hence, the fabricated 3D integrated circuits are lighter and smaller compared to traditional metal circuits, and with high electrical properties. The 3D integrated circuits, therefore, have a bright future prospect.

Processing, characterization and hemostatic mechanism of a ultraporous collagen/ORC biodegradable composite with excellent biological effectiveness.

Collagen, one of the most biocompatible materials in nature, is widely used in wound healing and organ repair. However, the limited mechanical strength and biological effectiveness of collagen restrain its application as a hemostasis and filling material in medicine. To overcome these limitations, ultraporous collagen/oxidized regenerated cellulose (Col/ORC) composites were prepared. The results showed that the Col-0.25%ORC composite had optimal wettability, porosity, and water absorption. An MTT assay proved that the Col and Col/ORC composites possessed no cytotoxicity in living cells. Evaluation of the hemostatic time in vivo and the amount of bleeding in two injury models revealed that the Col-0.25%ORC composite has the most outstanding biological effectiveness and could be biodegraded completely without any inflammatory reaction after 3 weeks. The SEM micrographs showed that the fasciculate ORC fibers were evenly dispersed into the reticulate structure of the Col sponge. The FT-IR spectra of the Col-ORC composites were completely different from that of neat ORC, but similar to Col spectra. Moreover, a possible hemostasis mechanism was discussed based on ELISA analysis, coagulation function, and physicochemical properties.

Hierarchical Proteinosomes for Programmed Release of Multiple Components.

A facile route to hierarchically organized multicompartmentalized proteinosomes based on a recursive Pickering emulsion procedure using amphiphilic protein-polymer nanoconjugate building blocks is described. The number of incarcerated guest proteinosomes within a single host proteinosome is controlled, and enzymes and genetic polymers encapsulated within targeted subcompartments to produce chemically organized multi-tiered structures. Three types of spatiotemporal response-retarded concomitant release, synchronous release or hierarchical release of dextran and DNA-are demonstrated based on the sequential response of the host and guest membranes to attack by protease, or through variations in the positioning of disulfide-containing cross-links in either the host or guest proteinosomes integrated into the nested architectures. Overall, our studies provide a step towards the construction of hierarchically structured synthetic protocells with chemically and spatially integrated proto-organelles.

An overview of the magnetoresistance phenomenon in molecular systems.

In this review, the classification of magnetoresistance effects, the electrical conduction mechanisms without and with magnetic field, and the spintronics are briefly summarized. The magnetoresistance effect in the molecular systems including small organic molecules, carbon nanotubes, graphene, conductive polymers and their nanocomposites is critically reviewed. The four normally used models are elaborated to disclose the mechanisms of organic magnetoresistance (OMAR) in the organic systems. The most current applications of these molecular systems are also summarized. These molecular systems are envisioned to create next-generation spintronic and electronic devices for flexible applications.

Generation of a photothermally responsive antimicrobial, bioadhesive gelatin methacryloyl (GelMA) based hydrogel through 3D printing for infectious wound healing.

Recently, photothermal nanomaterials has attracted enormous interests owing to their enhanced therapeutic effects and less adverse effects in the treatment of infectious diseases. Herein, this work presents a photothermally responsive antimicrobial, bioadhesive hydrogel through three dimensions (3D) printing technology for treatment the wound infection. The hydrogel is based on a visible-light-activated naturally derived polymer (GelMA), GelMA grafted with dopamine (GelMA-DA) and the polydopamine coated reduced graphene oxide (rGO@PDA), which can provide the multifunctional such as photothermal antibacterial, antioxidant, conductivity, adhesion and hemostasis performance to accelerate wound healing. The developed hydrogel shown the excellent adhesion capability to adhere the in vitro physiological tissues and glass surface. Moreover, the fabricated hydrogel also exhibited excellent cytocompatibility to L929 cells which is a vital biofunction for efficiently promoting cell proliferation and migration in vitro. The hydrogel also showed remarkable photothermally responsive antimicrobial capability against two strains (99.3 % antibacterial ratio for E. coli and 98.6 % antibacterial ratio for S. aureus). Furthermore, it could support the wound repair and regeneration of S. aureus infected full-thickness wound defects in rats. Overall, the 3D printed hydrogel could be used as a photothermal platform for the development of more effective therapies against the infected wound.

Investigation of the Single-Particle Scale Structure-Activity Relationship Providing New Insights for the Development of High-Performance Batteries.

As electric vehicles, portable electronic devices, and tools have increasingly high requirements for battery energy density and power density, constantly improving battery performance is a research focus. Accurate measurement of the structure-activity relationship of active materials is key to advancing the research of high-performance batteries. However, conventional performance tests of active materials are based on the electrochemical measurement of porous composite electrodes containing active materials, polymer binders, and conductive carbon additives, which cannot establish an accurate structure-activity relationship with the physical characterization of microregions. In this review, in order to promote the accurate measurement and understanding of the structure-activity relationship of materials, the electrochemical measurement and physical characterization of energy storage materials at single-particle scale are reviewed. The potential problems and possible improvement schemes of the single particle electrochemical measurement and physical characterization are proposed. Their potential applications in single particle electrochemical simulation and machine learning are prospected. This review aims to promote the further application of single particle electrochemical measurement and physical characterization in energy storage materials, hoping to achieve 3D unified evaluation of physical characterization, electrochemical measurement, and theoretical simulation at the single particle scale to provide new inspiration for the development of high-performance batteries.

Accurate and rapid mercury susceptibility detection in aquatic samples using fluorescent probe integrated rhodamine with pyridyl isothiocyanate.

Mercury, one of the various harmful metals, is particularly significant in affecting aquatic organisms, currently gaining more attentions and sparking discussions. In response to the limitations of traditional detections, fluorescent probes have emerged as a promising solution with some advantages, such as weaker background interference, shorter processing time, higher accuracy. Thus, a novel fluorescent probe, FS-Hg-1, has been developed for assessing mercury ion (Hg2+) concentrations in aquatic products. This probe displays specific recognition of mercury ions in fluorescence spectra. Notably, FS-Hg-1 exhibits a distinct color change to pink when combined with Hg2+ (with a 948-fold increase in absorption at 568 nm) and a substantial fluorescence change towards Hg2+ (361-fold increase, excitation at 562 nm, emission at 594 nm) in N, N-dimethylformamide. The probe boasts a detection limit of 0.14 µM and rapid reaction with Hg2+ within 10 s, showing an excellent linear correlation with [Hg2+] in the range of 0 to 10 µM. Through thorough analysis using FS-Hg-1, the results align with those from the standard method (P > 0.05), with spiked recovery rates ranging from 108.4% to 113.2%. With its precise recognition, low detection limit, and remarkable sensitivity, this fluorescent assay proves effective in mercury concentration determination in aquatic samples without interference. The potential of FS-Hg-1 is promising for speedy detection of residual Hg2+ and holds significance in ensuring food safety.

Facilitating the mechanical properties of a high-performance pH-sensitive membrane by cross-linking graphene oxide and polyacrylic acid.

Graphene represents a two-dimensional material having extraordinary physical properties, which make it a prospective material for many applications. In particular, graphene oxide (GO), with abundant chemical functional groups, further extends the new functions of graphene-based materials. However, the preparation of GO materials through chemical reactions remains a challenge to materials science. Here, using suitable cross-linkable polymers, a GO-polyacrylic acid (PAA) composite membrane was prepared by a gel-desiccation approach. The fabricated membrane displays both well controlled mechanical characteristics and unique multiple pH response.