Effect of a dynamic navigation device on the accuracy of implant placement in the completely edentulous mandible: An in vitro study.

STATEMENT OF PROBLEM: A less invasive and more convenient workflow is needed for dynamic navigation-guided implant surgery for the edentulous arch. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of a novel dynamic navigation device developed for the completely edentulous mandible. MATERIAL AND METHODS: Two temporary 1-piece mini-implants were placed in the anterior region of a completely edentulous mandibular model for fixation of the navigation device. A total of 40 implants were inserted in 10 completely edentulous mandibular models with the aid of the dynamic navigation device. The accuracy of placement was determined by overlapping the preoperative plan with the postoperative cone beam computed tomography (CBCT) scans. The difference in the accuracy at different implant positions was compared by MANOVA and Bonferroni-corrected ANOVAs. The difference in accuracy between implants #1-20 and #21-40 was assessed for learning progression. RESULTS: The deviation of the implants (mean ±standard deviation) was 1.14 ±0.50 mm at the entry point and 1.29 ±0.48 mm at the apex. The mean ±standard deviation angular deviation was 3.02 ±1.32 degrees. No significant difference was seen between the planned and the placed deviation among the 4 implant positions. After repeated placement with this dynamic approach, implant accuracy at the entry (P=.001) and apex (P=.017) improved significantly. CONCLUSIONS: The navigation device achieved acceptable implant placement accuracy in the edentulous mandible. Deviations between the planned and placed locations were not affected by different implant positions. After repeated operations with this dynamic approach, accuracy at the entry and apex improved significantly.

Comparison of the accuracy of immediate implant placement using static and dynamic computer-assisted implant system in the esthetic zone of the maxilla: a prospective study.

PURPOSE: This study aimed to compare the accuracy of fully guided between dynamic and static computer-assisted implant surgery (CAIS) systems for immediate implant placement in the esthetic zone. METHODS: A total of 40 qualified patients requiring immediate implant placement in the esthetic zone were randomly and equally assigned to either static CAIS group (n = 20) or dynamic CAIS groups (n = 20). Global deviations at entry, apex, and angular deviation between placed and planned implant position were measured and compared as primary outcomes. Secondary outcomes were the deviation of implant placement at mesial-distal, labial-palatal, and coronal-apical directions. RESULTS: For the immediate implant placement, the mean global entry deviations in static and dynamic CAIS groups were 0.99 ± 0.63 mm and 1.06 ± 0.55 mm (p = 0.659), while the mean global apex deviations were 1.50 ± 0.75 mm and 1.18 ± 0.53 mm (p = 0.231), respectively. The angular deviation in the static and dynamic CAIS group was 3.07 ± 2.18 degrees and 3.23 ± 1.67 degrees (p = 0.547). No significant differences were observed for the accuracy parameters of immediate implant placement between static and dynamic CAIS systems, except the deviation of the implant at entry in the labial-palatal direction in the dynamic CAIS group was significantly more labial than of the static CAIS (p = 0.005). CONCLUSIONS: This study demonstrated that clinically acceptable accuracy of immediate implant placement could be achieved using static and dynamic CAIS systems. Trial registration ChiCTR, ChiCTR2200056321. Registered 3 February 2022, http://www.chictr.org.cn/showproj.aspx?proj=151348.

Atomically Intimate Solid Electrolyte/Electrode Contact Capable of Surviving Long-Term Cycling with Repeated Phase Transitions.

The electrode-electrolyte contact issue within the composite electrode layer is a grand challenge for all-solid-state Li batteries. In order to achieve cycling performances comparable to Li-ion batteries based on liquid electrolyte, the aforementioned solid-solid contact not only needs to be sufficiently thorough but also must tolerate repeated cycling. Simultaneously meeting both requirements is rather challenging. Here, we discover that epitaxy may effectively overcome such bottlenecks even when the electrode undergoes repeated phase transitions during cycling. Through epitaxial growth, the perovskite Li0.33La0.56TiO3 solid electrolyte was found capable of forming atomically intimate contact with both the spinel Li4Ti5O12 and rock-salt Li7Ti5O12. In contrast to conventional expectations, such epitaxial interfaces can also survive repeated spinel-to-rock-salt phase transitions. Consequently, the Li4Ti5O12-Li0.33La0.56TiO3 composite electrode based on epitaxial solid-solid contact delivers not only a rate capability comparable to that of the surry-cast one with solid-liquid contact but also an excellent long-term cycling stability.

P2-Type Layered Na0.75Ni1/3Ru1/6Mn1/2O2 Cathode Material with Excellent Rate Performance for Sodium-Ion Batteries.

Layered oxides acting as sodium hosts have attracted extensive attention due to their structural flexibility and large theoretical capacity. However, the diffusion of Na ions always presents sluggish kinetics due to the larger ionic radius sand mass of Na compared to Li. Herein, we report a P2-type layered cathode material, namely, Na0.75Ni1/3Ru1/6Mn1/2O2 with superfast ion transport, where the Na+ diffusion coefficient is calculated mainly in the region of 10-10 to 10-11 cm2 s-1 during the charge and discharge process. The electrochemical tests also show that this cathode material exhibits a high capacity of 161.5 mAh g-1, excellent rate performance (when the rate increases from 0.2C-10C, the capacity retention is 74%), and outstanding cyclic performance (maintaining 79.5% for 500 cycles even at a high rate of 10C). Our findings provide new insights for the design of the open framework for fast transport of Na and promote the high-power performance of sodium-ion batteries (SIBs).

Electrochemical and Structural Analysis in All-Solid-State Lithium Batteries by Analytical Electron Microscopy: Progress and Perspectives.

Advanced scanning transmission electron microscopy (STEM) and its associated instruments have made significant contributions to the characterization of all-solid-state (ASS) Li batteries, as these tools provide localized information on the structure, morphology, chemistry, and electronic state of electrodes, electrolytes, and their interfaces at the nano- and atomic scale. Furthermore, the rapid development of in situ techniques has enabled a deep understanding of interfacial dynamic behavior and heterogeneous characteristics during the cycling process. However, due to the beam-sensitive nature of light elements in the interphases, e.g., Li and O, thorough and reliable studies of the interfacial structure and chemistry at an ultrahigh spatial resolution without beam damage is still a formidable challenge. Herein, the following points are discussed: (1) the recent contributions of advanced STEM to the study of ASS Li batteries; (2) current challenges associated with using this method; and (3) potential opportunities for combining cryo-electron microscopy and the STEM phase contrast imaging techniques.

Strong optical response and light emission from a monolayer molecular crystal.

Excitons in two-dimensional (2D) materials are tightly bound and exhibit rich physics. So far, the optical excitations in 2D semiconductors are dominated by Wannier-Mott excitons, but molecular systems can host Frenkel excitons (FE) with unique properties. Here, we report a strong optical response in a class of monolayer molecular J-aggregates. The exciton exhibits giant oscillator strength and absorption (over 30% for monolayer) at resonance, as well as photoluminescence quantum yield in the range of 60-100%. We observe evidence of superradiance (including increased oscillator strength, bathochromic shift, reduced linewidth and lifetime) at room-temperature and more progressively towards low temperature. These unique properties only exist in monolayer owing to the large unscreened dipole interactions and suppression of charge-transfer processes. Finally, we demonstrate light-emitting devices with the monolayer J-aggregate. The intrinsic device speed could be beyond 30 GHz, which is promising for next-generation ultrafast on-chip optical communications.

Dandelion-like Mn/Ni Co-doped CoO/C Hollow Microspheres with Oxygen Vacancies for Advanced Lithium Storage.

Hollow structures have attracted great attention based on the advantage to accommodate volume expansion. However, template removal usually results in structure destruction. Herein, dandelion-like Mn/Ni co-doped CoO/C hollow microspheres (CMNC-10h) are synthesized via an Ostwald ripening process without templates. The high-angle annular dark field mapping images at the atomic level indicate the successful doping of Mn and Ni into CoO. Via an annular bright field image, oxygen vacancies induced by doping can be clearly observed. The residual two electrons in the oxygen vacancy site are highly delocalized, as confirmed by density functional theory calculations, effectively improving electrical conductivity. According to electron holography analysis, the dielectric polarization field in superficial regions of primary nanoparticles can facilitate insertion of Li+ ions into nanoparticles and thus enhance electrochemical kinetics. Combining those advantages, CMNC-10h demonstrates a high capacity of 1126 mAh g-1 at 1 A g-1 after 1000 cycles as anode material for a lithium-ion battery. Additionally, based on the strong adsorption toward polysulfide, the porous structure to accommodate sulfer/polysulfide, and the effects of oxygen vacancies to immobilize and catalyze polysulfide, CMNC-10h-S as cathode material for a lithium-sulfur battery also displays a high capacity of 642 mAh g-1 after 500 cycles at 1 C.

Understanding the role of aluminium in determining the surface structure and electrochemical performance of layered cathodes.

The electrochemical properties of layered cathodes can be enhanced by doping with aluminium. However, understanding of the underlying mechanism of Al ion behaviour is deficient, which obstructs its further application. Herein, we adjusted the aluminium content in model LiNi0.85-xCo0.15AlxO2 (LNCA) materials; the sample with the optimum aluminium content (x = 0.05) exhibited excellent electrochemical performance (98.6% capacity retention at 275 mA g-1). Meanwhile, for the samples with excessive aluminium (x = 0.15, 0.30), fast decay of the cycling stability could be observed. Meanwhile, their reversible capacities in the initial cycles were also greatly inferior to the theoretical values. These abnormal phenomena can be attributed to structure cracking and the impedance of Li-ion migration in samples with higher aluminium content. According to the microstructure observations, an unexpected beneficial heterostructure was found to cover the samples with optimum aluminium content, while in the samples with higher aluminium content, this heterostructure was not present. Furthermore, as confirmed by activation barrier calculations, Al ions were found to prefer to thermodynamically occupy the tetrahedral interstices instead of the octahedral sites in Li layers in a high delithiation state. Due to this selective occupancy, proper aluminium content can improve the stability of layered cathodes during cycling. However, excessive aluminium content instead impedes the formation of beneficial surface heterogeneity during synthesis and deeply affects Li-ion migration during cycling. Therefore, the electrochemical performance of the samples with higher aluminium content suffered severe decay. These results and discoveries significantly advance the guidance of microstructural design for next-generation layered cathode materials.

A Flexible Film toward High-Performance Lithium Storage: Designing Nanosheet-Assembled Hollow Single-Hole Ni-Co-Mn-O Spheres with Oxygen Vacancy Embedded in 3D Carbon Nanotube/Graphene Network.

Ternary transition metal oxides (TMOs) are highly potential electrode materials for lithium ion batteries (LIBs) due to abundant defects and synergistic effects with various metal elements in a single structure. However, low electronic/ionic conductivity and severe volume change hamper their practical application for lithium storage. Herein, nanosheet-assembled hollow single-hole Ni-Co-Mn oxide (NHSNCM) spheres with oxygen vacancies can be obtained through a facile hydrothermal reaction, which makes both ends of each nanosheet exposed to sufficient free space for volume variation, electrolyte for extra active surface area, and dual ion diffusion paths compared with airtight hollow structures. Furthermore, oxygen vacancies could improve ion/electronic transport and ion insertion/extraction process of NHSNCM spheres. Thus, oxygen-vacancy-rich NHSNCM spheres embedded into a 3D porous carbon nanotube/graphene network as the anode film ensure efficient electrolyte infiltration into both the exterior and interior of porous and open spheres for a high utilization of the active material, showing an excellent electrochemical performance for LIBs (1595 mAh g-1 over 300 cycles at 2 A g-1 , 441.6 mAh g-1 over 4000 cycles at 10 A g-1 ). Besides, this straightforward synthetic method opens an efficacious avenue for the construction of various nanosheet-assembled hollow single-hole TMO spheres for potential applications.

Cyclic tensile stress promotes osteogenic differentiation of adipose stem cells via ERK and p38 pathways.

The present study aimed to elucidate whether extracellular signal-regulated kinases 1/2 (ERK1/2) and p38 mitogen-activated protein kinases pathways participate in the transduction of mechanical stretch exerted on adipose stem cells (ASCs) into intracellular osteogenic signals, and if so whether both pathways have time-dependent feature. Rat ASCs were cultured in osteogenic medium for 72 h and assigned into three sets, namely ERK1/2 inhibitor treated set, p38 inhibitor treated set, and the control set. After inhibitor treatment, all cells were subjected to cyclic stretch(2000 µÎµ, 1 Hz) on a four-point bending mechanical loading device. Protein and mRNA samples were acquired at six time points: 0, 15 min, 30 min, 1 h, 2 h and 6 h. Western blot showed phosphorylation level of ERK1/2 was elevated by cyclic tensile stress at all time points, while p38 at 15 min, 30 min and 1 h, and the elevation can be completely blocked by corresponding inhibitors. The treatment by ERK1/2 inhibitor was shown to antagonize the up-regulation of osteogenic genes bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (Runx2) by mechanical stretch at 15 min and 6 h, whereas p38 inhibitor took effect at 15 min only. The results suggested both ERK and p38 could be positive mediators of stretch-induced osteogenic differentiation of ASCs, and ERK stimulate the stretch-induced osteogenic differentiation at both early and late stages while p38 responds to mechanical stretch in a more rapid fashion.

Superior-capacity binder-free anode electrode for lithium-ion batteries: CoxMnyNizO nanosheets with metal/oxygen vacancies directly formed on Cu foil.

Recently, transition metal oxides have attracted great attention as anode materials for lithium-ion batteries due to their high theoretical capacities. However, their poor electrical conductivity, unstable cycling performance and unclear additional capacity are still great challenges. Herein, CoxMnyNizO (x : y : z = 8 : 0.92 : 0.71) nanosheets corresponding to the cubic CoO phase directly formed on a Cu foil (CMN-CH) were fabricated and directly tested as binder-free anode electrodes for lithium-ion batteries. The unique preparation of the electrode without a binder effectively accelerated the transfer of Li+ ions and electrons. Additionally, much more active sites were exposed to the electrolyte in the absence of additives (binder and conductive carbon). Metal vacancies and oxygen vacancies could be clearly observed in the crystal lattices, which were induced by doping Mn and Ni atoms in the CoO crystal lattices. The prepared CMN-CH electrode demonstrated superior capacities of 1501 mA h g-1 at 5 A g-1 after 1500 cycles and 823 mA h g-1 at 10 A g-1 after 1500 cycles, which are far beyond the theoretical capacity of CoO (716 mA h g-1) and surpass that of most CoO-based composites with carbon materials reported in the literature. The reversible conversion between Co2+ and Co3+ during the cycling process contributed greatly to the reversible capacity. Based on the obtained excellent electrochemical capacities, the prepared CMN-CH has great potential to be used as an anode electrode for lithium-ion batteries.

Magnetic Semiconductor Gd-Doping CuS Nanoparticles as Activatable Nanoprobes for Bimodal Imaging and Targeted Photothermal Therapy of Gastric Tumors.

Targeted delivery of enzyme-activatable probes into cancer cells to facilitate accurate imaging and on-demand photothermal therapy (PTT) of cancers with high spatiotemporal precision promises to advance cancer diagnosis and therapy. Here, we report a tumor-targeted and matrix metalloprotease-2 (MMP-2)-activatable nanoprobe (T-MAN) formed by covalent modification of Gd-doping CuS micellar nanoparticles with cRGD and an MMP-2-cleavable fluorescent substrate. T-MAN displays a high r1 relaxivity (∼60.0 mM-1 s-1 per Gd3+ at 1 T) and a large near-infrared (NIR) fluorescence turn-on ratio (∼185-fold) in response to MMP-2, allowing high-spatial-resolution magnetic resonance imaging (MRI) and low-background fluorescence imaging of gastric tumors as well as lymph node (LN) metastasis in living mice. Moreover, T-MAN has a high photothermal conversion efficiency (PCE, ∼70.1%) under 808 nm laser irradiation, endowing it with the ability to efficiently generate heat to kill tumor cells. We demonstrate that T-MAN can accumulate preferentially in gastric tumors (∼23.4% ID%/g at 12 h) after intravenous injection into mice, creating opportunities for fluorescence/MR bimodal imaging-guided PTT of subcutaneous and metastatic gastric tumors. For the first time, accurate detection and laser irradiation-initiated photothermal ablation of orthotopic gastric tumors in intraoperative mice was also achieved. This study highlights the versatility of using a combination of dual biomarker recognition (i.e., αvß3 and MMP-2) and dual modality imaging (i.e., MRI and NIR fluorescence) to design tumor-targeting and activatable nanoprobes with improved selectivity for cancer theranostics in vivo.

Enhancing the Structural Stability of Ni-Rich Layered Oxide Cathodes with a Preformed Zr-Concentrated Defective Nanolayer.

Nickel-rich layered oxides (NLOs) exhibit great potential to meet the ever-growing demand for further increases in the energy density of Li-ion batteries because of their high specific capacities. However, NLOs usually suffer from severe structural degradation and undesired side reactions when cycled above 4.3 V. These effects are strongly correlated with the surface structure and chemistry of the active NLO materials. Herein, we demonstrate a preformed cation-mixed ( Fm3̅ m) surface nanolayer (∼5 nm) that shares a consistent oxygen framework with the layered lattice through Zr modification, in which Ni cations reside in Li slabs and play the role of a "pillar". This preformed nanolayer alleviates the detrimental phase transformations upon electrochemical cycling, effectively enhancing the structural stability. As a result, the Zr-modified Li(Ni0.8Co0.1Mn0.1)0.985Zr0.015O2 material exhibits a high reversible discharge capacity of ∼210 mA h/g at 0.1 C (1 C = 200 mA/g) and outstanding cycling stability with a capacity retention of 93.2% after 100 cycles between 2.8 and 4.5 V. This strategy may be further extended to design and prepare other high-performance layered oxide cathode materials.