Biomass-derived cellulose nanocrystals modified nZVI for enhanced tetrabromobisphenol A (TBBPA) removal.

Nano zero-valent iron (nZVI) is an advanced environmental functional material for the degradation of tetrabromobisphenol A (TBBPA). However, high surface energy, self-agglomeration and low electron selectivity limit degradation rate and complete debromination of bare nZVI. Herein, we presented biomass-derived cellulose nanocrystals (CNC) modified nZVI (CNC/nZVI) for enhanced TBBPA removal. The effects of raw material (straw, filter paper and cotton), process (time, type and concentration of acid hydrolysis) and synthesis methods (in-situ and ex-situ) on fabrication of CNC/nZVI were systematically evaluated based on TBBPA removal performance. The optimized CNC-S/nZVI(in) was prepared via in-situ liquid-phase reduction using straw as raw material of CNC and processing through 44 % H2SO4 for 165 min. Characterizations illustrated nZVI was anchored to the active sites at CNC interface through electrostatic interactions, hydrogen bonds and FeO coordinations. The batch experiments showed 0.5 g/L CNC-S/nZVI(in) achieved 96.5 % removal efficiency at pH = 7 for 10 mg/L initial TBBPA. The enhanced TBBPA dehalogenation by CNC-S/nZVI(in), involving in initial adsorption, reduction process and partial detachment of debrominated products, were possibly attributed to elevated pre-adsorption capacity and high-efficiency delivery of electrons synergistically. This study indicated that fine-tuned fabrication of CNC/nZVI could potentially be a promising alternative for remediation of TBBPA-contaminated aquatic environments.

Cellulose nanocrystals intercalated clay biocomposite for rapid Cr(VI) removal.

The application of bentonite (Bt) as an adsorbent for heavy metals has been limited due to its hydrophobicity and insufficient surface area. Herein, we present cellulose nanocrystal (CNC) modified Bt composite (CNC@Bt) with enhanced efficiency for Cr(VI) removal. CNC@Bt exhibited an increased specific surface area and a porous structure, while maintaining the original crystal structure of Bt. This was achieved through a synergistic function of ion exchange, hydrogen bonding, electrostatic interactions, and steric hindrance. The adsorption of Cr(VI) by CNC@Bt followed the pseudo-second-order kinetic and Langmuir isotherm adsorption model. Moreover, the process was endothermic and spontaneous. At an initial Cr(VI) concentration of 20 mg/L and pH = 4.0, 10 g/L CNC@Bt achieved a removal rate of 92.7%, and the adsorption capacity was 1.85 mg/g, significantly higher than bare Bt (37.9% and 0.76 mg/g). The removal efficiency remained consistently above 80% over a wide pH range, indicating the potential practical applicability of CNC@Bt. With its fast adsorption rate, pH adaptability, and stable performance, CNC@Bt presents promising prospects for the rapid treatment of Cr-contaminated wastewater.

Compliant Grasping Control for a Tactile Self-Sensing Soft Gripper.

Soft grippers with good passive compliance can effectively adapt to the shape of a target object and have better safe grasping performance than rigid grippers. However, for soft or fragile objects, passive compliance is insufficient to prevent grippers from crushing the target. Thus, to complete nondestructive grasping tasks, precision force sensing and control are immensely important for soft grippers. In this article, we proposed an online learning self-tuning nonlinearity impedance controller for a tactile self-sensing two-finger soft gripper so that its grasping force can be controlled accurately. For the soft gripper, its grasping force is sensed by a liquid lens-based optical tactile sensing unit that contains a self-sensing fingertip and a liquid lens module and has many advantages of a rapid response time (about 0.04 s), stable output, good sensitivity (>0.4985 V/N), resolution (0.03 N), linearity (R2 > 0.96), and low cost (power consumption: 5 mW, preparation cost

TEMPO oxidized cellulose nanocrystal (TOCNC) scaffolded nanoscale zero-valent iron (nZVI) for enhanced chromium removal.

The conventional carboxymethyl cellulose (CMC) stabilization hampered available active sites of adsorption and reduction, due to irregular shape of nanoscale zero-valent iron (nZVI) particles with augmented average size and passivated surface, leading to insufficient removal and poor resistance against complex environmental conditions. Herein, we presented (2,2,6,6-Tetramethylpiperidine-1-oxyl)-mediated (TEMPO-mediated) oxidation of cellulose nanocrystal (TOCNC) scaffolded nZVI (nZVI@TOCNC) with enhanced efficiency for chromium removal in comparison with CMC stabilized nZVI (nZVI@CMC). The anchoring of nZVI at the functional sites of TOCNC was initiated by liquid-phase chemical reduction method. The nZVI@TOCNC showed improved nZVI distribution with uniform particle size and thinner shell (∼1 nm). Characterizations using FT-IR, XPS and XRD demonstrated that bindings between TOCNC and nZVI were through hydrogen bonds, electrostatic attractions, coordination-covalent bonds and bidentate chelation. TOCNC with shorter branch-chain (-COC-) surrounding the nZVI could potentially form a porous and compact "mesh" to rigidly encapsulate nZVI, while CMC wrapped around nZVI in the way of traditional polymeric stabilizers. Thus, 0.5 g/L nZVI@TOCNC achieved 99.96% Cr (Ⅵ) removal efficiency (20 mg/L) at pH = 7 and the removal capacity were up to 55.86 mg/g. The nZVI@TOCNC consistently presented higher removal efficiency than nZVI@CMC under wide pH range (3-7). Cr (Ⅵ) was reduced to Cr (Ⅲ) by nZVI@TOCNC with deposition of CrxFe1-x (OH)3 and Cr2O3. The predominant mechanisms of removal probably consisted of electrostatic attractions, reduction, co-precipitation and surface complexation. The pseudo-second-order kinetic model well-fitted the sorption kinetic, indicating TOCNC scaffold stabilized nZVI for efficient reduction of Cr (Ⅵ) through multi-layer adsorption. As a template and delivery carrier, TOCNC shows promising potential to further improve the capability and practice of nZVI for in situ treatment of industrial waste water with heavy metal pollution.

Research on a Super-Resolution and Low-Complexity Positioning Algorithm Using FMCW Radar Based on OMP and FFT in 2D Driving Scene.

Multitarget positioning technology, such as FMCW millimeter-wave radar, has broad application prospects in autonomous driving and related mobile scenarios. However, it is difficult for existing correlation algorithms to balance high resolution and low complexity, and it is also difficult to ensure the robustness of the positioning algorithm using an aging antenna. This paper proposes a super-resolution and low-complexity positioning algorithm based on the orthogonal matching pursuit algorithm that can achieve more accurate distance and angle estimation for multiple objects in a low-SNR environment. The algorithm proposed in this paper improves the resolving power by two and one orders of magnitude, respectively, compared to the classical FFT and MUSIC algorithms in the same signal-to-noise environment, and the complexity of the algorithm can be reduced by about 25-30%, with the same resolving power as the OMP algorithm. Based on the positioning algorithm proposed in our paper, we use the PSO algorithm to optimize the arrangement of an aging antenna array so that its angle estimation accuracy is equivalent to that observed when the antenna is intact, improving the positioning algorithm's robustness. This paper also further realizes the use of the proposed algorithm and a single-frame intermediate frequency signal to estimate the position angle information of the object and obtain its motion trajectory and velocity, verifying the proposed algorithm's estimation ability when it comes to these qualities in a moving scene. Furthermore, this paper designs and carries out simulations and experiments. The experimental results verify that the positioning algorithm proposed in this paper can achieve accuracy, robustness, and real-time performance in autonomous driving scenarios.

Formulation and stabilization of high internal phase emulsions: Stabilization by cellulose nanocrystals and gelatinized soluble starch.

In this work, high internal phase emulsions (HIPEs) stabilized by naturally derived cellulose nanocrystals (CNC) and gelatinized soluble starch (GSS) were fabricated to stabilize oregano essential oil (OEO) in the absence of surfactant. The physical properties, microstructures, rheological properties, and storage stability of HIPEs were investigated by adjusting CNC contents (0.2, 0.3, 0.4 and 0.5 wt%) and starch concentration (4.5 wt%). The results revealed that CNC-GSS stabilized HIPEs exhibited good storage stability within one month and the smallest droplets size at a CNC concentration of 0.4 wt%. The emulsion volume fractions of 0.2, 0.3, 0.4 and 0.5 wt% CNC-GSS stabilized HIPEs after centrifugation reached 77.58, 82.05, 94.22, and 91.41 %, respectively. The effect of native CNC and GSS were analyzed to understand the stability mechanisms of HIPEs. The results revealed that CNC could be used as an effective stabilizer and emulsifier to fabricate the stable and gel-like HIPEs with tunable microstructure and rheological properties.

Role of Enterococcus faecalis in refractory apical periodontitis: from pathogenicity to host cell response.

BACKGROUND: Refractory apical periodontitis (RAP) is an oral infectious disease characterised by persistent inflammation, progressive alveolar bone destruction, and delayed bone healing. RAP has received increasing attention, because it cannot be cured after repeated root canal therapies. The aetiology of RAP is related to the complex interplay between the pathogen and its host. However, the exact pathogenesis of RAP remains unclarified and includes several factors, such as microorganism immunogenicity, host immunity and inflammation, and tissue destruction and repair. Enterococcus faecalis is the dominant pathogen involved in RAP, and has evolved multiple strategies to ensure survival, which cause persistent intraradicular and extraradicular infections. OBJECTIVE: To review the crucial role of E. faecalis in the pathogenesis of RAP, and open new avenues for prevention and treatment of RAP. METHODS: The PubMed and Web of Science databases were searched for pertinent publications, employing the search terms "Enterococcus faecalis", "refractory apical periodontitis", "persistent periapical periodontitis", "pathogenicity", "virulence", "biofilm formation", "dentine tubule", "immune cell", "macrophage", and "osteoblast". RESULTS AND CONCLUSION: Besides its high pathogenicity due to various virulence mechanisms, E. faecalis modulates the macrophage and osteoblast responses, including regulated cell death, cell polarisation, cell differentiation, and inflammatory response. An in-depth understanding of the multifaceted host cell responses modulated by E. faecalis will help to design potential future therapeutic strategies and overcome the challenges of sustained infection and delayed tissue healing in RAP.

Electrochemical monitoring of 4-chlorophenol as a water pollutant via carbon paste electrode amplified with Fe3O4 incorporated cellulose nanofibers (CNF).

A crucial problem that needs to be resolved is the sensitive and selective monitoring of chlorophenol compounds, especifically 4-chlorophenol (4-CP), one of the most frequently used organic industrial chemicals. In light of this, the goal of this study was to synthesize Fe3O4 incorporated cellulose nanofiber composite (Fe3O4/CNF) as an amplifier in the development of a modified carbon paste electrode (CPE) for 4-CP detection. Transmission electron microscopy (TEM) was used to evaluate the morphology of the synthesized nanocatalyst, while differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) techniques were implemented to illuminate the electrochemical characteristics of the fabricated sensor. The ultimate electrochemical sensor (Fe3O4/CNF/CPE) was used as a potent electrochemical sensor for monitoring 4-CP in the concentration range of 1.0 nM-170 µM with a limit of detection value of 0.5 nM. As a result of optimization studies, 8.0 mg Fe3O4/CNF was found to be the ideal catalyst concentration, whereas pH = 6.0 was chosen as the ideal pH. The 4-CP's oxidation current was found to be over 1.67 times greater at ideal operating conditions than it was at the surface of bare CPE, and its oxidation potential decreased by about 120 mV. By using the standard addition procedure on samples of drinking water and wastewater, the suggested capability of Fe3O4/CNF/CPE to detect 4-CP was further investigated. The recovery range was found to be 98.52-103.66%. This study paves the way for the customization of advanced nanostructure for the application in electrochemical sensors resulting in beneficial environmental impact and enhancing human health.

Value of nuclide scintigraphy in the diagnosis and prognosis of cardiac amyloidosis. / æ ¸ç´ æ˜¾åƒåœ¨å¿ƒè„æ·€ç²‰æ ·å˜è¯Šæ–­åŠé¢„åŽè¯„ä¼°ä¸­çš„ä»·å€¼.

Amyloidosis is a local or systemic disease caused by the deposition of misfolded proteins outside the cell, with rapid progression, and dire prognosis. Common types of cardiac amyloidosis are monoclonal immunoglobulin light chain amyloidosis (AL-CA) and transthyretin cardiac amyloidosis (ATTR-CA). Nuclear medicine examinations can be accurate, rapid, and non-invasive to help diagnose diseases and can effectively predict the prognosis of patients with CA. Technetium (99Tcm)-labeled bisphosphonate imaging has been included in the consensus of experts and has become the first-line imaging method for the diagnosis of ATTR-CA. 123I-metaiodoenzylguanidine (MIBG) as a norepinephrine analogue can effectively assess cardiac sympathetic innervation in patients with CA. Aß- amyloid imaging agents such as 11C-pittsburgh compound B and 18F-flubetaben are expected to be new techniques for diagnosing AL-CA and incorporating them into cardiac staging systems for AL-CA patients in the future. New imaging agents such as 18F-NaF has been widely used in the diagnosis, treatment response monitoring, and prognosis assessment of CA. Summarizing the research value of nuclide imaging in CA may provide new ideas for clinical realization of early detection of CA and accurate assessment of disease prognosis.

Preparation, Characterization and Antibacterial Property Analysis of Cellulose Nanocrystals (CNC) and Chitosan Nanoparticles Fine-Tuned Starch Film.

To improve the mechanical and antibacterial properties of traditional starch-based film, herein, cellulose nanocrystals (CNCs) and chitosan nanoparticles (CS NPs) were introduced to potato starch (PS, film-forming matrix) for the preparation of nanocomposite film without incorporation of additional antibacterial agents. CNCs with varied concentrations were added to PS and CS NPs composite system to evaluate the optimal film performance. The results showed that tensile strength (TS) of nanocomposite film with 0, 0.01, 0.05, and 0.1% (w/w) CNCs incorporation were 41, 46, 47 and 41 MPa, respectively. The elongation at break (EAB) reached 12.5, 10.2, 7.1 and 13.3%, respectively. Due to the reinforcing effect of CNCs, surface morphology and structural properties of nanocomposite film were altered. TGA analysis confirmed the existence of hydrogen bondings and electrostatic attractions between components in the film-forming matrix. The prepared nanocomposite films showed good antibacterial properties against both E. coli and S. aureus. The nanocomposite film, consist of three most abundant biodegradable polymers, could potentially serve as antibacterial packaging films with strong mechanical properties for food and allied industries.

Electrochemical sensor amplified with cellulose nanofibers/Fe3O4 composite to the monitoring of hydrazine as a pollutant in water and wastewater samples.

A quite swift and sensitive analytical instrument was designed in this work to detect and monitor hydrazine in various water and wastewater samples. The glassy carbon electrode (GCE) was amplified using cellulose nanofibers/Fe3O4 composite (CNF-Fe3O4/NC) for monitoring hydrazine in the concentration range of 0.001 - 140 M with a superior detection limit of 0.5 nM. Results showed a diffusion control process for the oxidation of hydrazine at the surface of CNF-Fe3O4/NC/GCE. Under the optimum condition (pH=8.0), the oxidation current of hydrazine was improved by about 2.3 times and the oxidation potential was reduced by about 60 mV at the surface of CNF-Fe3O4/NC/GCE compare to unmodified GCE. A standard addition method was employed to assess CNF-Fe3O4/NC/GCE's capability for the detection of hydrazine in water and wastewater samples, and a recovery range of 97.6 % to 104.9 % was noted.

Nanocellulose fine-tuned poly(acrylic acid) hydrogel for enhanced diclofenac removal.

Hydrogel was recognized as one of the most promising materials for adsorption of pharmaceuticals and personal care products (PPCPs). The highly efficient bio-based nanocelluloses fine-tuned poly(acrylic acid) hydrogel (PAA/NC) adsorbent was constructed by adjusting aspect ratio, surface charge and crystallinity of NC. The cross-linked networks were fabricated through a single-step free-radical polymerization via steric effect and hydrogen bonds. The uniform three-dimensional structures with abundant macropores and mesopores were in-situ visualized by the cryogenic-scanning electron microscopy (Cryo-SEM). The diclofenac adsorption capacity of TEMPO oxidized cellulose nanofibers (TCNF) incorporated PAA hydrogel (PAA/TCNF, 559.8 mg·g-1) was circa 2.1 times higher than pristine PAA (293.5 mg·g-1) due to the elevated specific surface area, favorable spatial structure with unimpeded channels and abundant surface-charged carboxylic groups. Moreover, PAA/NC hydrogel exhibited a wide-pH applicability and high salinity tolerance. The adsorption was predominantly determined by hydrogen bonds, validated by XPS and FT-IR analysis. It was demonstrated developed PAA/NC hydrogel with unique porous structure significantly enhanced adsorption capacity for potential application in the purification of refractory organic pollutants-containing wastewater.

Enterococcus faecalis-Induced Macrophage Necroptosis Promotes Refractory Apical Periodontitis.

The persistence of residual bacteria, particularly Enterococcus faecalis, contributes to refractory periapical periodontitis, which still lacks effective therapy. The role of receptor-interacting protein kinase 3 (RIPK3)- and mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis, a highly proinflammatory form of regulated cell death, has recently drawn much attention. However, the role of necroptosis in the pathogenesis of refractory periapical periodontitis remains unclear. We investigated whether the RIPK3/MLKL signaling pathway was activated in periapical lesion specimens obtained from patients diagnosed with refractory periapical periodontitis. RIPK3-deficient mice were then used to determine the role of necroptosis under this condition in vivo. We found that the phosphorylation levels of RIPK3 and MLKL were elevated in periapical lesion specimens of patients with refractory periapical periodontitis. In addition, necroptosis was induced in an E. faecalis-infected refractory periapical periodontitis mouse model, in which inhibition of necroptosis by RIPK3 deficiency could markedly alleviate inflammation and bone destruction. Moreover, double-labeling immunofluorescence suggested that macrophage necroptosis may be involved in the development of refractory periapical periodontitis. Then, we established an in vitro macrophage infection model with E. faecalis. E. faecalis infection was found to induce necroptotic cell death in macrophages through the RIPK3/MLKL signaling pathway, which was markedly alleviated by the RIPK3- or MLKL-specific inhibitor. Our study revealed that RIPK3/MLKL-mediated macrophage necroptosis contributes to the development of refractory periapical periodontitis and suggests that inhibitors or treatments targeting necroptosis represent a plausible strategy for the management of refractory periapical periodontitis. IMPORTANCE Oral infectious diseases represent a major neglected global population health challenge, imposing an increasing burden on public health and economy. Refractory apical periodontitis (RAP), mainly caused by Enterococcus faecalis, is a representative oral infectious disease with considerable therapeutic challenges. The interplay between E. faecalis and the host often leads to the activation of programmed cell death. This study identifies an important role of macrophage necroptosis induced by E. faecalis in the pathogenesis of RAP. Manipulating RIPK3/MLKL-mediated necroptosis may represent novel therapeutic targets, not only for RAP but also for other E. faecalis-associated infectious diseases.

Storage Quality Variation of Mushrooms (Flammulina velutipes) after Cold Plasma Treatment.

Flammulina velutipes is susceptible to mechanical damage, water loss, microbial growth, and other factors that lead to postharvest deterioration, thereby shortening the storage period. The purpose of this study was to analyze the effects of cold plasma treatment on the physicochemical properties and antioxidant capacity of F. velutipes during storage at 4 °C for 21 days. Compared to the control group, cold plasma cold sterilization (CPCS) treatment (150 Hz, 95 kV for 150 s) effectively inhibited the growth and multiplication of microorganisms on the surface of F. velutipes, with no significant effect on the fresh weight change and the superoxide anion generation rate, but with a higher postharvest 1,1-dephenyl-2-picrylhydrzyl (DPPH) clearance rate. Moreover, CPCS increased antioxidant enzyme activities, delayed both malondialdehyde (MDA) accumulation and vitamin C loss, inhibited the browning reaction and polyphenol oxidases (PPO) activity and protected F. velutipes cell membrane from disruption. In general, CPCS not only achieved bacteriostatic effects on F. velutipes during storage, but also reduced cell damage from free radical oxidation, resulting in better postharvest quality and longer shelf life.

Effects of N-cadherin silencing on the proliferation and migration of human dental pulp stem cells / 口腔疾病防治

Objective @#To investigate the effects of N-cadherin silencing on the proliferation and migration of human dental pulp stem cells (DPSCs) and to provide experimental evidence for DPSCs-based dental pulp regeneration.@* Methods@# DPSCs were transfected with N-cadherin shRNA lentivirus, and the knockdown efficiency of N-cadherin at both the mRNA and protein levels was confirmed by qRT-PCR and Western blot. The experiment included a negative control group (shRNA -NC) and an N-cadherin shRNA silencing group. Cell proliferation was detected by the CCK-8 method. Cell cycle and apoptosis were assessed by flow cytometry, and cell migration was detected using the Transwell method.@*Results@#N-cadherin shRNA significantly reduced the expression levels of N-cadherin mRNA and protein in DPSCs (P<0.001). The proliferation activity of the N-cadherin shRNA group was significantly greater than that of the shRNA-NC group on the 3rd and 4th days after cell inoculation and lower than that of the shRNA-NC group from the 6th to 8th days (P<0.05). On the 3rd day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.05). On the 6th day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was lower than that in the shRNA-NC group (P<0.05), and the proportion of apoptotic cells in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.01). Low densities cells and high densities cells were inoculated into Transwell upper chamber for 20 h, the number of cells passing through the membrane pores of upper chamber in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.001).@*Conclusion@#Silencing N-cadherin expression can promote the early proliferation and migration of DPSCs.

PANoptosis: A New Insight Into Oral Infectious Diseases.

The oral microbiome, one of the most complex and intensive microbial ecosystems in the human body, comprises bacteria, archaea, fungi, protozoa, and viruses. Dysbiosis of the oral microbiome is the initiating factor that leads to oral infectious diseases. Infection is a sophisticated biological process involving interplay between the pathogen and the host, which often leads to activation of programmed cell death. Studies suggest that pyroptosis, apoptosis, and necroptosis are involved in multiple oral infectious diseases. Further understanding of crosstalk between cell death pathways has led to pyroptosis, apoptosis, and necroptosis being integrated into a single term: PANoptosis. PANoptosis is a multifaceted agent of the immune response that has important pathophysiological relevance to infectious diseases, autoimmunity, and cancer. As such, it plays an important role in innate immune cells that detect and eliminate intracellular pathogens. In addition to the classical model of influenza virus-infected and Yersinia-infected macrophages, other studies have expanded the scope of PANoptosis to include other microorganisms, as well as potential roles in cell types other than macrophages. In this review, we will summarize the pathophysiological mechanisms underlying inflammation and tissue destruction caused by oral pathogens. We present an overview of different pathogens that may induce activation of PANoptosis, along with the functional consequences of PANoptosis in the context of oral infectious diseases. To advance our understanding of immunology, we also explore the strategies used by microbes that enable immune evasion and replication within host cells. Improved understanding of the interplay between the host and pathogen through PANoptosis will direct development of therapeutic strategies that target oral infectious diseases.

Microflora and umami alterations of different packaging material preserved mushroom (Flammulina filiformis) during cold storage.

In order to clarify the effect of nanocomposite-based packaging (NP) on umami and microflora characteristics of F. filiformis during cold storage, the contents of umami amino acids and 5'-nucleotides, equivalent umami concentration (EUC), and microflora succession were investigated. Results showed that NP could delay the degradation of umami components and inhibit bacterial growth in F. filiformis. At the initial stage, the dominant bacteria were Lactobacillus, Thermus and Acinetobacter. After 15 days of storage, the bacteria count in NP reached 7.63 lg cfu/g, which was significantly (P < 0.05) lower than that in control, and the major bacterial communities of packaged F. filiformis were Ewingella, Serratia and Pseudomonas. Moreover, the correlation analysis showed that Lactobacillus, Brevibacillus and Okibacterium were negatively correlated with AMP and IMP 5-nucleotides. Present work suggested that NP could enhance the umami flavor formation and improve the microbial community structure of F. filiformis, resulting in a better commercial quality. The results provided theoretical basis for large-scale applications of NP.

Efficacy of i-PRF in regenerative endodontics therapy for mature permanent teeth with pulp necrosis: study protocol for a multicentre randomised controlled trial.

BACKGROUND: Dental pulp necrosis, a common health problem, is traditionally treated with root canal therapy; however, it fails in restoring the vitality of damaged pulp. Most studies regarding regenerative endodontic therapy (RET) are limited to the treatment of immature necrotic teeth. Given that injectable platelet-rich fibrin (i-PRF) has shown great potential in regenerative medicine as a novel platelet concentration, this study is designed to explore whether i-PRF can serve as a biological scaffold, extending the indications for RET and improving the clinical feasibility of RET in mature permanent teeth with pulp necrosis. METHODS: This is a randomised, double-blind, controlled, multicentre clinical trial designed to evaluate the clinical feasibility of RET for mature permanent teeth with pulp necrosis and to compare the efficacy of i-PRF and blood clots as scaffolds in RET. A total of 346 patients will be recruited from three centres and randomised at an allocation ratio of 1:1 to receive RET with either a blood clot or i-PRF. The changes in subjective symptoms, clinical examinations, and imaging examinations will be tracked longitudinally for a period of 24 months. The primary outcome is the success rate of RET after 24 months. The secondary outcome is the change in pulp vitality measured via thermal and electric pulp tests. In addition, the incidence of adverse events such as discolouration, reinfection, and root resorption will be recorded for a safety evaluation. DISCUSSION: This study will evaluate the clinical feasibility of RET in mature permanent teeth with pulp necrosis, providing information regarding the efficacy, benefits, and safety of RET with i-PRF. These results may contribute to changes in the treatment of pulp necrosis in mature permanent teeth and reveal the potential of i-PRF as a novel biological scaffold for RET. TRIAL REGISTRATION: ClinicalTrials.gov NCT04313010 . Registered on 19 March 2020.

Necroptosis in Macrophage Foam Cells Promotes Fat Graft Fibrosis in Mice.

Background: Fibrosis is a major grafting-related complication that leads to fat tissue dysfunction. Macrophage-induced inflammation is related to the development of fat tissue fibrosis. Necroptosis is a recently discovered pathway of programmed cell necrosis that results in severe inflammation and subsequent tissue fibrosis. Thus, in this study, we investigated the role of macrophage necroptosis in fat graft fibrosis and the underlying mechanisms. Methods: Fibrosis and necroptosis were investigated in mouse fat tissue before and after grafting. An in vitro "crown-like" structure (CLS) cell culture model was developed by co-culturing RAW 264.7 macrophages with apoptotic adipocytes to reproduce in vivo CLS macrophage-adipocyte interactions. Lipid uptake and necroptosis in CLS macrophages were analyzed using Oil-Red-O staining, western blotting, and immunofluorescence. RAW264.7 macrophages were cultured alone or with apoptotic adipocytes and treated with a necroptosis inhibitor (Nec-1 or GSK872) to explore the paracrine effect of necroptotic CLS macrophages on collagen synthesis in fibroblasts in vitro. Mice were treated with Nec-1 to analyze the effect of blocking necroptosis on fat graft fibrosis. Results: Fibrosis was increased after grafting in fat grafts of mice. Macrophages clustered around apoptotic adipocytes or large oil droplets to form a typical CLS in fibrotic depots. This was accompanied by formation and necroptosis of macrophage foam cells (MFCs) in CLSs. RAW 264.7 macrophages co-cultured with apoptotic adipocytes induced CLS formation in vitro, and lipid accumulation in CLS macrophages resulted in the formation and necroptosis of MFCs. Necroptosis of MFCs altered the expression of collagen I and VI in fibroblasts via a paracrine mechanism involving inflammatory cytokines/chemokines, which was reversed by GSK872 or Nec-1 treatment. Furthermore, treatment with Nec-1 ameliorated fat graft fibrosis in mice. Conclusion: Apoptotic adipocytes induced necroptosis of MFCs, and necroptosis of these cells activated collagen synthesis in fibroblasts via a paracrine mechanism. Inhibition of necroptosis in macrophages is a potential approach to prevent fibrosis in fat grafts.

N-Cadherin Regulates the Odontogenic Differentiation of Dental Pulp Stem Cells via ß-Catenin Activity.

Dental pulp stem cell (DPSC) transplantation has shown new prospects in dental pulp regeneration, and is of great significance in the treatment of pulpitis and pulp necrosis. The fate and regenerative potential of stem cells are dependent, to a great extent, on their microenvironment, which is composed of various tissue components, cell populations, and soluble factors. N-cadherin-mediated cell-cell interaction has been implicated as an important factor in controlling the cell-fate commitment of mesenchymal stem cells. In this study, the effect of N-cadherin on odontogenic differentiation of DPSCs and the potential underlying mechanisms, both in vitro and in vivo, was investigated using a cell culture model and a subcutaneous transplantation mouse model. It was found that the expression of N-cadherin was reversely related to the expression of odontogenic markers (dentin sialophosphoprotein, DSPP, and runt-related transcription factor 2, Runx2) during the differentiation process of DPSCs. Specific shRNA-mediated knockdown of N-cadherin expression in DPSCs significantly increased the expression of DSPP and Runx2, alkaline phosphatase (ALP) activity, and the formation of mineralized nodules. Notably, N-cadherin silencing promoted nucleus translocation and accumulation of ß-catenin. Inhibition of ß-catenin by a specific inhibitor XAV939, reversed the facilitating effects of N-cadherin downregulation on odontogenic differentiation of DPSCs. In addition, knockdown of N-cadherin promoted the formation of odontoblast-like cells and collagenous matrix in ß-tricalcium phosphate/DPSCs composites transplanted into mice. In conclusion, N-cadherin acted as a negative regulator via regulating ß-catenin activity during odontogenic differentiation of DPSCs. These data may help to guide DPSC behavior by tuning the N-cadherin-mediated cell-cell interactions, with implications for pulp regeneration.