Optimization of synergistic capturing platinum group metals by Fe-Sn and its mechanism.

Platinum group metals (PGMs) are strategic metals. Auto-exhaust catalysts are their main application fields. The recovery of PGMs from spent auto-exhaust catalysts has remarkable economic value and strategic significance. Aiming at the problems of ferrosilicon generation for Fe capturing and subsequent oxygen blowing to remove iron with high energy consumption and heat release, a technology of Fe-Sn synergistic capturing PGMs was proposed. Taking full the advantage of the lower melting point of Fe-Sn alloy (<1200 °C) and its unique affinity for PGMs, the PGMs were captured at approximate 1400 °C with Fe-Sn as the collector. In experiment, 500 g of spent auto-exhaust catalysts were employed to minimize error and approximate industrial production. The mechanism of Fe-Sn synergistic capturing PGMs was elucidated. The generation of Fe-Sn-PGMs alloy lowered the activity of [PGMs] in the system, accelerated the reduction of the PGMs oxides and promoted the alloying of [PGMs]. Therefore, Fe-Sn synergistic capturing PGMs was realized. The inability of Si to enter the alloy phase was confirmed by theoretical calculations, avoiding the generation of ferrosilicon. The effects of basicity, CaF2, m(Fe)/m(Sn) and the amount of collector on capturing PGMs were optimized. Under the optimized conditions (basicity R = 1.1, spent auto-exhaust catalysts 70 wt%, CaO 30 wt%, B2O3 10 wt%, CaF2 7 wt%, m(Fe)/m(Sn) = 1/1 and the collector 15 wt%), the content of PGMs in the slag phase was 2.46 g/t. It is feasible to remove Fe and Sn by oxidation to achieve the purpose of PGMs enrichment. This technology offers guidance on the safe, environmentally sound, and efficient disposal of spent auto-exhaust catalysts, promoting the sustainable development of PGMs.

Immediate implant placement in the posterior mandibular region was assisted by dynamic real-time navigation: a retrospective study.

BACKGROUND: Efficient utilization of residual bone volume and the prevention of inferior alveolar nerve injury are critical considerations in immediate implant placement (IIP) within the posterior mandibular region. Addressing these challenges, this study focuses on the clinical efficacy and implant accuracy of dynamic real-time navigation, an emerging technology designed to enhance precision in implantation procedures. METHODS: This study included 84 patients with 130 implants undergoing immediate placement in the posterior mandibular region. Stratified into dynamic navigation, static guide plate, and freehand implant groups, clinical indicators, including initial stability, distance to the inferior alveolar nerve canal, depth of implant placement, and various deviations, were systematically recorded. Statistical analysis, employing 1- or 2-way ANOVA and Student's t-test, allowed for a comprehensive evaluation of the efficacy of each technique. RESULTS: All 130 implants were successfully placed with an average torque of 22.53 ± 5.93 N.cm. In the navigation group, the distance to the inferior alveolar nerve and the depth of implant placement were significantly greater compared to the guide plate and freehand groups (P < 0.05). Implant deviation was significantly smaller in both the navigation and guide plate groups compared to the freehand group(P < 0.05). Additionally, the navigation group exhibited significantly reduced root and angle deviations compared to the guide plate group(P < 0.05), highlighting the superior precision of navigation-assisted immediate implant placement. CONCLUSIONS: It is more advantageous to use dynamic navigation rather than a static guide plate and free-hand implant insertion for immediate posterior mandibular implant implantation.

Application of Computer-Aided Design and Individualized Templates for Bilateral Zygomaticomaxillary Complex Fractures.

PURPOSE: Reduction of the bilateral zygomaticomaxillary complex (ZMC) fracture with individualized templates based on computer- aided surgical simulation system. To evaluate the practicality and accuracy of this approach in the treatment of bilateral ZMC fracture. METHODS: Sixteen patients with bilateral ZMC fractures were collected to create a study model. The authors reconstruct the ZMC on one side via the three-dimensional (3D) model, and then mirrored to the opposite side. Multiple individualized templates were made based on the 3D model, and used as intraoperative guidance to reduce fractures. After surgery, the facial symmetry and the position of zygoma were observed. The mouth opening, pupil level, and sensation of infraorbital nerve were evaluated. Some mark points on zygoma were measured and the postoperative horizontal asymmetry rate (H) was calculated. Besides, orbital height and width were measured. RESULTS: For all patients, the position of bilateral ZMC was basically restored. The patients with restriction of mouth opening all recovered to normal. The H values were less than 3.0% at all mark points. There was almost no difference in bilateral orbital width and height. Meanwhile, there was no significant difference between the preoperative measurements of the ideal virtual 3D model and the postoperative measurements of patients. CONCLUSIONS: The study proves that application of computer-aided design and individualized templates can accurately guide the reduction operation of ZMC fracture, restore the ideal shape of ZMC, and obtain good facial symmetry.

Impact of Hyperbaric Oxygen on the Healing of Teeth Extraction Sockets and Alveolar Ridge Preservation.

OBJECTIVES: The purpose of this study was to investigate the role of hyperbaric oxygen (HBO) in the healing of teeth extraction sockets and in alveolar ridge preservation. This may provide an experimental basis for the widespread application of HBO in oral implantation. METHODS: A total of 32 beagle dogs were included in the study and randomly divided equally between an HBO group treated with hyperbaric oxygen (100% O2, 2.4 atm, 90 min/day, 5 times/week, 6 weeks) and a normobaric oxygen (NBO) group treated with normal air in the same chamber. The lateral incisors of the maxillary and mandible of each dog were extracted, and the right upper and lower incisor extraction sockets (A2C2) were allowed to heal naturally, while left upper and lower incisor sockets (B2D2) received implants of a commercial bone substitute. At 4 and 8 weeks after surgery, clinical observation, cone-beam computerized tomography (CBCT), histomorphology observation, and expression levels of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) were analyzed to evaluate new bone formation, mineralization, and reconstruction. RESULTS: After 4 and 8 weeks, bone width and lip contour of the extraction socket in the NBO group were significantly reduced and collapsed in comparison with the HBO group. CBCT showed that the difference in vertical height between the alveolar crest of the labial tongue and palatal side of the extraction sockets was smaller in the HBO than NBO group. There was a significant difference in new bone formation (P < 0.05) and bone mineral density (P < 0.05) between the HBO and NBO groups, and the HBO group showed significantly greater new bone and bone reconstruction based on histology. Furthermore, the expression levels of VEGF and BMP-2 were higher in the HBO group. CONCLUSION: HBO reduced bone resorption and promoted early bone formation, bone mineralization, and reconstruction in the extraction sockets. HBO greatly reduced the healing time of the extraction sockets and promoted alveolar ridge preservation, thus showing promise for the clinic.

DNA-Inspired Strand-Exchange for Switchable PMMA-Based Supramolecular Morphologies.

Inspired by nanotechnologies based on DNA strand displacement, herein we demonstrate that synthetic helical strand exchange can be achieved through tuning of poly(methyl methacrylate) (PMMA) triple-helix stereocomplexes. To evaluate the utility and robustness of helical strand exchange, stereoregular PMMA/polyethylene glycol (PEG) block copolymers capable of undergoing crystallization driven self-assembly via stereocomplex formation were prepared. Micelles with spherical or wormlike morphologies were formed by varying the molecular weight composition of the assembling components. Significantly, PMMA strand exchange was demonstrated and utilized to reversibly switch the micelles between different morphologies. This concept of strand exchange with PMMA-based triple-helix stereocomplexes offers new opportunities to program dynamic behaviors of polymeric materials, leading to scalable synthesis of "smart" nanosystems.

Controlled Formation and Binding Selectivity of Discrete Oligo(methyl methacrylate) Stereocomplexes.

The triple-helix stereocomplex of poly(methyl methacrylate) (PMMA) is a unique example of a multistranded synthetic helix that has significant utility and promise in materials science and nanotechnology. To gain a fundamental understanding of the underlying assembly process, discrete stereoregular oligomer libraries were prepared by combining stereospecific polymerization techniques with automated flash chromatography purification. Stereocomplex assembly of these discrete building blocks enabled the identification of (1) the minimum degree of polymerization required for the stereocomplex formation and (2) the dependence of the helix crystallization mode on the length of assembling precursors. More significantly, our experiments resolved binding selectivity between helical strands with similar molecular weights. This presents new opportunities for the development of next-generation polymeric materials based on a triple-helix motif.

Star Polymers.

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

A Versatile and Scalable Strategy to Discrete Oligomers.

A versatile strategy is reported for the multigram synthesis of discrete oligomers from commercially available monomer families, e.g., acrylates, styrenics, and siloxanes. Central to this strategy is the identification of reproducible procedures for the separation of oligomer mixtures using automated flash chromatography systems with the effectiveness of this approach demonstrated through the multigram preparation of discrete oligomer libraries (D = 1.0). Synthetic availability, coupled with accurate structural control, allows these functional building blocks to be harnessed for both fundamental studies as well as targeted technological applications.

Aromaticity/Bulkiness of Surface Ligands to Promote the Interaction of Anionic Amphiphilic Gold Nanoparticles with Lipid Bilayers.

The presence of large hydrophobic aromatic residues in cell-penetrating peptides or proteins has been demonstrated to be advantageous for their cell penetration. This phenomenon has also been observed when AuNPs were modified with peptides containing aromatic amino acids. However, it is still not clear how the presence of hydrophobic and aromatic groups on the surface of anionic AuNPs affects their interaction with lipid bilayers. Here, we studied the interaction of a range of anionic amphiphilic AuNPs coated by different combinations of hydrophobic and anionic ligands with four different types of synthetic lipid vesicles. Our results demonstrated the important role of the surface aromatic or bulky groups, relative to the hydrocarbon chains, in the interaction of anionic AuNPs with lipid bilayers. Hydrophobic interaction itself arising from the insertion of aromatic/bulky ligands on the surface of AuNPs into lipid bilayers is sufficiently strong to cause overt disruption of lipid vesicles and cell membranes. Moreover, by comparing the results obtained from AuNPs coated with aromatic ligands and cyclohexyl ligands lacking aromaticity respectively, we demonstrated that the bulkiness of the terminal groups in hydrophobic ligands instead of the aromatic character might be more important to the interaction of AuNPs with lipid bilayers. Finally, we further correlated the observation on model liposomes with that on cell membranes, demonstrating that AuNPs that are more disruptive to the more negatively charged liposomes are also substantially more disruptive to cell membranes. In addition, our results revealed that certain cellular membrane domains that are more susceptible to disruption caused by hydrophobic interactions with nanoparticle surfaces might determine the threshold of AuNP-mediated cytotoxicity.

Effect of Food Emulsifiers on Aroma Release.

This study aimed to determine the influence of different emulsifiers or xanthan-emulsifier systems on the release of aroma compounds. Solid-phase microextraction (SPME) and GC-MS were used to study the effects of varying concentrations of xanthan gum, sucrose fatty acid ester, Tween 80 and soybean lecithin on the release of seven aroma compounds. The effects of the emulsifier systems supplemented with xanthan gum on aroma release were also studied in the same way. The results showed varying degrees of influence of sucrose fatty acid ester, soybean lecithin, Tween 80 and xanthan gum on the release of aroma compounds. Compared with other aroma compounds, ethyl acetate was more likely to be conserved in the solution system, while the amount of limonene released was the highest among these seven aroma compounds. In conclusion, different emulsifiers and complexes showed different surface properties that tend to interact with different aroma molecules. The present studies showed that the composition and structure of emulsifiers and specific interactions between emulsifiers and aroma molecules have significant effects on aroma release.

Biodegradable and multifunctional polymer micro-tubes for targeting photothermal therapy.

We describe an innovative form of polymer micro-tubes with diverse functions including biodegradation, magnetic manipulation, and photothermal effect that employs and activates photothermal therapy to target cancer cells. The micro-tube comprised soybean protein isolate, poly-l-glutamic acid, magnetite nanoparticles, plus gold nanoparticles. Through electrostatic force, these components, with opposite charges, formed pairs of layers in the pores of the template, various bilayers of soybean protein isolate and poly-l-glutamic acid served as the biodegradable building wall to each micro-tube. The layers of magnetite nanoparticle functionalized micro-tubes enabled the micro-tube manipulate to target the cancer cells by using an external magnetic field. The photo-thermal effect of the layer of gold nanoparticles on the outer surface of the micro-tubes, when under irradiation and when brought about by the near infrared radiation, elevated each sample's temperature. In addition, and when under the exposure of the near infrared radiation, the elevated temperature of the suspension of the micro-tubes, likewise with a concentration of 0.2 mg/mL, and similarly with a power of 2 W and as well maintained for 10 min, elevated the temperature of the suspension beyond 42 °C. Such temperatures induced apoptosis of target cancer cells through the effect of photothermal therapy. The findings assert that structured micro-tubes have a promising application as a photothermal agent. From this assertion, the implications are that this multifunctional agent will significantly improve the methodology for cancer diagnosis and therapy.

[Enhancers on the transmembrane transport of chlorogenic acid].

To investigate the influence of the difference enhancers on the transport mechanism of chlorogenic acid (CGA) across Caco-2 cells model, a RP-HPLC method was adopted to detect the concentrations of CGA. At the concentrations of 20 to 80 microg x mL(-1), the difference of absorption rate constants (K(a)) was not statistically significant. At the concentrations of 40 and 20 microg x mL(-1), the ratios of apparent permeability coefficients (P(app)) of the apical to basolateral and the basolateral to apical were 1.14 and 1.18, respectively. With the effect of enhancers K(a) and P(app) increased, the absorption half-life (T1/2) decreased. CGA passed through the Caco-2 cell membrane mainly by passive transport. It showed that monocarboxylic acid transporter (MCT) could be involved in the across membrane transport process of CGA. Borneol had no effect on the cell membrane transport processes. The order of increasing absorption of CGA caused by the enhancers was sodium lauryl sulphate > sodium taurocholate > carbomer.

Stereospecific cyclic poly(methyl methacrylate) and its topology- guided hierarchically controlled supramolecular assemblies.

In this study, the stereocomplexation between a novel stereospecific cyclic vinyl polymer, that is, cyclic syndiotactic poly(methyl methacrylate) (st-PMMA), with the complementary linear isotactic (it-) PMMA was investigated. Surprising new insight into the effects of the topology (i.e., end groups), size, and tacticity of the assembling components on stereocomplex formation was obtained. Characterization of the stereocomplexes revealed that the self-assembly of cyclic st-PMMAs and linear it-PMMAs resulted in the formation of an unprecedented "polypseudorotaxane-type" supramolecular assembly. This stereocomplex exhibited remarkably different physical properties as compared to the conventional PMMA triple-helix stereocomplex as a result of the restricted topology imposed by the cyclic st-PMMA assembling component.

Putative pathogenic factors underlying Streptococcus oralis opportunistic infections.

Streptococcus oralis, belonging to the viridans group streptococci (VGS), has been considered a component of the normal flora predominantly inhabiting the oral cavity. In recent years, a growing body of literature has revealed that dental procedures or daily tooth brushing activities can cause the spread of S. oralis from the oral cavity into various body sites leading to life-threatening opportunistic infections such as infective endocarditis (IE) and meningitis. However, very little is currently known about the pathogenicity of S. oralis. Thus, the aim of this review is to update the current understanding of the pathogenic potential of S. oralis to pave the way for the prevention and treatment of S. oralis opportunistic infections.

Enhanced drug resistance suppression by serum-stable micelles from multi-arm amphiphilic block copolymers and tocopheryl polyethylene glycol 1000 succinate.

Aim: To develop a robust drug-delivery system using multi-arm amphiphilic block copolymers for enhanced efficacy in cancer therapy. Materials & methods: Two series of amphiphilic polymer micelles, PEG-b-PCLm and PEG-b-PCLm/TPGS, were synthesized. Doxorubicin (DOX) loading into the micelles was achieved via solvent dialysis. Results: The micelles displayed excellent biocompatibility, narrow size distribution, and uniform morphology. DOX-loaded micelles exhibited enhanced antitumor efficacy and increased drug accumulation at tumor sites compared with free DOX. Additionally, 4A-PEG47-b-PCL21/TPGS micelles effectively suppressed drug-resistant MCF-7/ADR cells. Conclusion: This study introduces a novel micelle formulation with exceptional serum stability and efficacy against drug resistance, promising for cancer therapy. It highlights innovative strategies for refining clinical translation and ensuring sustained efficacy and safety in vivo.

[Box: see text].

Clinical study of dynamic real-time navigation assisted immediate implant without flapping in the esthetic zone.

OBJECTIVE: The purpose of this study is to investigate the clinical effect of Dynamic real-time navigation to assist immediate implant without flapping in the esthetic zone. METHODS: Eight patients who underwent immediate implantation in the aesthetic area were included. A total of 11 implants were implanted using dynamic real-time navigation system combined with non-flap technology. Clinical indicators including implant deviation, initial stability, alveolar bone absorption, implant success rate, pink esthetic score (PES), Papilla index score (PIS), and the thickness of labial side bone plate of the implant were recorded. RESULTS: The deviation between the actual implant position and the preoperative design was (0.76±0.08) mm at the top, (1.11±0.18) mm at the root, (0.90±0.16) mm at the depth, and (1.48±0.91)°at the Angle. ISO values of all implants were greater than 59. PES was greater than 8. PIS index was 2 or 3. The average alveolar bone absorption was (0.34±0.09) mm and the thickness of bone plate on the lip of implant was greater than 1.6 mm. The success rate of implantation was 100%. CONCLUSION: The use of dynamic real-time navigation assisted non-flap implantation in the aesthetic area can effectively reduce implant deviation and improve the aesthetic effect.

Novel molecularly imprinted phenolic resin-dispersive filter extraction for rapid determination of perfluorooctanoic acid and perfluorooctane sulfonate in milk.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are emerging pollutants that threaten food safety. Herein, a rapid, accurate, and selective method for determination of PFOA and PFOS in milk was established by using new molecularly imprinted phenolic resin (MIP-PR) as the adsorbent of dispersive filter extraction (DFE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). MIP-PR was synthesized at room-temperature using m-aminophenol, glutaraldehyde, and perfluorononanoic acid as the monomers, cross-linkers, and virtual templates, respectively, and exhibited rapid mass transfer (30 s), high selectivity (imprinted factors > 3.7), and large adsorption capacity (>54.6 mg/g). Compared with reported methods, the developed MIP-PR-DFE method is fast, selective, inexpensive, and shows good purification and enrichment efficiency. The proposed MIP-PR-DFE-LC-MS/MS exhibited low limits of detection (0.006-0.022 ng/mL), high recoveries (94.7-109 %), and good precision (RSDs ≤ 9.5 %). This study provides a new idea for the development of imprinted resin adsorbents for perfluorinated compound, and a new method for sample pretreatment for monitoring of PFOA and PFOS in food.

Transcriptome analysis of osteogenic differentiation of human maxillary sinus mesenchymal stem cells using RNA-Seq.

Recent studies have demonstrated that human maxillary sinus mesenchymal stem cells (hMSMSCs) have osteogenic potential and can be osteogenically induced. Here, we investigated pivotal molecular functions and candidates that contribute to the osteogenic differentiation of hMSMSCs. Human maxillary sinus membranes were harvested from 3 patients with jaw deformities. hMSMSCs from human maxillary sinus membranes were osteogenically induced for 0 or 21 days. Subsequently, their functional profiles were analysed by RNA sequencing and validated by quantitative PCR. Compared with control hMSMSCs, osteogenically induced hMSMSCs showed (1) osteogenic differentiation phenotype, as evidenced by the cell nodes, alizarin red staining, osteogenesis-related protein, and RNA expression; (2) accelerated osteogenic process of ossification and calcium signalling, as demonstrated by Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway; (3) enriched osteogenesis gene expression of SMOC2, OMD, IGF1, JUNB, BMP5, ADRA1A, and IGF2, which was validated by quantitative PCR. Based on by these results, we demonstrated that accelerated ossification process, calcium signalling, and upregulation of SMOC2, OMD, IGF1, JUNB, BMP5, ADRA1A and IGF2, may contribute to the osteogenic differentiation of hMSMSCs.

Regulation of endothelial cells on the osteogenic ability of bone marrow mesenchymal stem cells in peri-implantitis.

OBJECTIVES: The relationship between bone resorption and angiogenesis in peri-implantitis remains to be studied. We constructed a Beagle dog model of peri-implantitis, and extracted bone marrow mesenchymal stem cells (BMSCs) and endothelial cells (ECs) for culture. The osteogenic ability of BMSCs in the presence of ECs was investigated through an in vitro osteogenic induction model, and its mechanism was initially explored. SUBJECTS AND METHODS: The peri-implantitis model was verified by ligation, bone loss was observed by micro-CT, and cytokines were detected by ELISA. The isolated BMSCs and ECs were cultured to detect the expression of angiogenesis, osteogenesis-related proteins, and NF-κB signaling pathway-related proteins. RESULTS: 8 weeks after surgery, the peri-implant gums were swollen, and micro-CT showed bone resorption. Compared with the control group, IL-1ß, TNF-α, ANGII and VEGF were markedly increased in the peri-implantitis group. In vitro studies found that the osteogenic differentiation ability of BMSCs co-cultured with IECs was decreased, and the expression of NF-κB signaling pathway-related cytokines was increased. CONCLUSION: Endothelial cells inhibit the osteogenic differentiation of bone marrow mesenchymal stem cells through NF-κB signaling in the environment of peri-implantitis, which may become a new target for the treatment of peri-implantitis.

Conditioned media of deer antler stem cells accelerate regeneration of alveolar bone defects in rats.

The destruction of periodontal alveolar bone (AB) caused by periodontitis is regarded as one of the major reasons for tooth loss. The inhibition of bone resorption and regeneration of lost AB are the desirable outcomes in clinical practice but remain in challenge. The use of mesenchymal stem cells (MSCs) is one current approach for achieving true restoration of AB defects (ABD). Antler stem cells (AnSC) are capable of renewing a huge mammalian bony appendage, the deer antler, suggesting an unparalleled potential for bone regeneration. Herein, we investigated the effectiveness of deer AnSCs conditioned medium (CM, AnSC-CM) for repair of surgically-created ABD using a rat model and sought to define the underlying mechanisms. The results showed that AnSC-CM effectively induced regeneration of AB tissue; the outcome was significantly better than human bone marrow mesenchymal stem cell conditioned medium (hBMSC-CM). AnSC-CM treatment upregulated osteogenic factors and downregulated osteoclastic differentiation factors; stimulated proliferation, migration and differentiation of resident MSCs toward osteogenic lineage cells; modulated macrophage polarization toward the M2 phenotype and suppressed osteoclastogenesis. That AnSC-CM resulted in better outcomes than hBMSC-CM in treating ABD was attributed to the cell compatibility as both AnSCs and AB tissue are neural crest-derived. In conclusion, the effects of AnSC-CM on AB tissue regeneration were achieved through both promotion of osteogenesis and inhibition of osteoclastogenesis. We believe that AnSC-CM is a candidate for effective treatment of ABD in dental clinical practice but will require investment in further development.