Porous Poly(ionic Liquid) Membrane with Metal Nanoparticle Gradient: A Smart Actuator for Visualizing Chemical Reactions.

Poly(ionic liquid) (PIL)-based porous membranes are extensively investigated as soft polymer actuators. While PILs have shown significant advancements in membrane fabrication and stabilization of metal nanoparticles (MNPs), research on integrating MNPs into porous membranes to achieve actuation behavior under multiple stimuli is limited. Herein, this work presents a new paradigm for designing a porous PIL-polyacrylic acid (PAA) membrane with a distinct MNP gradient via a top-bottom diffusion approach involving a metal salt precursor solution and NaBH4 as a reducing agent. The strong binding sites provided by PILs, combined with the gradient distribution of -COO- groups across the membrane cross-section, play a significant role in controlling the MNPs' gradient distribution. Interestingly, the MNPs within the membrane display excellent catalytic activity in exothermic reactions such as H2O2 decomposition, dissipating uneven heat that quickly permeates the membrane network. This induces asymmetrical swelling of polymer chains, resulting in rapid membrane bending. Furthermore, such MNP-loaded membrane could serve as a portable test paper for visually monitoring H2O2. This advancement paves the way for the development of intricate smart actuation materials and expands their practical applications in various real-life scenarios.

Baicalin can enhance odonto/osteogenic differentiation of inflammatory dental pulp stem cells by inhibiting the NF-κB and ß-catenin/Wnt signaling pathways.

BACKGROUND: Scutellaria baicalensis Georgi is a famous traditional Chinese medicine, which is widely used in treating fever, upper respiratory tract infection and other diseases. Pharmacology study showed it can exhibit anti-bacterial, anti-inflammation and analgesic effects. In this study, we investigated the effect of baicalin on the odonto/osteogenic differentiation of inflammatory dental pulp stem cells (iDPSCs). METHODS AND RESULTS: iDPSCs were isolated from the inflamed pulps collected from pulpitis. The proliferation of iDPSCs was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2,5-tetrazolium bromide (MTT) assay and flow cytometry. Alkaline phosphatase (ALP) activity assay, alizarin red staining, Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assay were conducted to examine the differentiation potency along with the involvement of nuclear factor kappa B(NF-κB) and ß-catenin/Wnt signaling pathway. MTT assay and cell-cycle analysis demonstrated that baicalin had no influence on the proliferation of iDPSCs. ALP activity assay and alizarin red staining demonstrated that baicalin could obviously enhance ALP activity and calcified nodules formed in iDPSCs. RT-PCR and Western blot showed that the odonto/osteogenic markers were upregulated in baicalin-treated iDPSCs. Moreover, expression of cytoplastic phosphor-P65, nuclear P65, and ß-catenin in iDPSCs was significantly increased compared with DPSCs, but the expression in baicalin-treated iDPSCs was inhibited. In addition, 20 µM Baicalin could accelerate odonto/osteogenic differentiation of iDPSCs via inhibition of NF-κB and ß-catenin/Wnt signaling pathways. CONCLUSION: Baicalin can promote odonto/osteogenic differentiation of iDPSCs through inhibition of NF-κB and ß-catenin/Wnt pathways, thus providing direct evidence that baicalin may be effective in repairing pulp with early irreversible pulpitis.

Enhancing bacterial cellulose production with hypoxia-inducible factors.

Komagataeibacter xylinus is an aerobic strain that produces bacterial cellulose (BC). Oxygen levels play a critical role in regulating BC synthesis in K. xylinus, and an increase in oxygen tension generally means a decrease in BC production. Fumarate nitrate reduction protein (FNR) and aerobic respiration control protein A (ArcA) are hypoxia-inducible factors, which can signal whether oxygen is present in the environment. In this study, FNR and ArcA were used to enhance the efficiency of oxygen signaling in K. xylinus, and globally regulate the transcription of the genome to cope with hypoxic conditions, with the goal of improving growth and BC production. FNR and ArcA were individually overexpressed in K. xylinus, and the engineered strains were cultivated under different oxygen tensions to explore how their overexpression affects cellular metabolism and regulation. Although FNR overexpression did not improve BC production, ArcA overexpression increased BC production by 24.0% and 37.5% as compared to the control under oxygen tensions of 15% and 40%, respectively. Transcriptome analysis showed that FNR and ArcA overexpression changed the way K. xylinus coped with oxygen tension changes, and that both FNR and ArcA overexpression enhanced the BC synthesis pathway. The results of this study provide a new perspective on the effect of oxygen signaling on growth and BC production in K. xylinus and suggest a promising strategy for enhancing BC production through metabolic engineering. KEY POINTS: • K. xylinus BC production increased after overexpression of ArcA • The young's modulus is enhanced by the ArcA overexpression • ArcA and FNR overexpression changed how cells coped with changes in oxygen tension.

Intracellular mRNA phase separation induced by cationic polymers for tumor immunotherapy.

The formation of biomolecular condensates via liquid‒liquid phase separation (LLPS) is an advantageous strategy for cells to organize their subcellular compartments for diverse functions. Recent findings suggest that RNA or RNA-related LLPS techniques have potential for the development of new cellular regulation strategies. However, manipulating RNA LLPS in living cells has great challenges. Herein, we report that cationic polymers (CPs) have strong RNA LLPS-inducing activity. By introducing CPs into living cells or RNA solutions, significant RNA LLPS was verified through confocal imaging, turbidity assays, and fluorescence recovery after photobleaching (FRAP) tests. Among them, turbidity kinetics determinations indicated that the hydrophilic positively charged amino groups on the CPs play essential roles in RNA phase separation. Moreover, the LLPS induced by the cationic polymers dramatically changed the gene expression patterns in the cells. Interestingly, we found that TGFß1 mRNA was highly encapsulated in the RNA droplets, which lowered the immunosuppressive capability of the tumor cells and triggered marked antitumor reactions in a mouse breast cancer model. Thus, we present here the CP-based modulation of RNA LLPS as a novel transcriptional manipulation method with potential for cancer immunotherapy drug development.

AUXIN RESPONSE FACTOR17 Directly Regulates MYB108 for Anther Dehiscence.

The timely release of mature pollen following anther dehiscence is essential for reproduction in flowering plants. AUXIN RESPONSE FACTOR17 (ARF17) plays a crucial role in pollen wall pattern formation, tapetum development, and auxin signal transduction in anthers. Here, we showed that ARF17 is also involved in anther dehiscence. The Arabidopsis (Arabidopsis thaliana) arf17 mutant exhibits defective endothecium lignification, which leads to defects in anther dehiscence. The expression of MYB108, which encodes a transcription factor important for anther dehiscence, was dramatically down-regulated in the flower buds of arf17 Chromatin immunoprecipitation assays and electrophoretic mobility shift assays showed ARF17 directly binds to the MYB108 promoter. In an ARF17-GFP transgenic line, in which ARF17-GFP fully complements the arf17 phenotype, ARF17-GFP was observed in the endothecia at anther stage 11. The GUS signal driven by the MYB108 promoter was also detected in endothecia at late anther stages in transgenic plants expressing promoterMYB108::GUS Thus, the expression pattern of both ARF17 and MYB108 is consistent with the function of these genes in anther dehiscence. Furthermore, the expression of MYB108 driven by the ARF17 promoter successfully restored the defects in anther dehiscence of arf17 These results demonstrated that ARF17 regulates the expression of MYB108 for anther dehiscence. Together with its function in microcytes and tapeta, ARF17 likely coordinates the development of different sporophytic cell layers in anthers. The ARF17-MYB108 pathway involved in regulating anther dehiscence is also discussed.

Tailoring bacterial cellulose structure through CRISPR interference-mediated downregulation of galU in Komagataeibacter xylinus CGMCC 2955.

Diverse applications of bacterial cellulose (BC) have different requirements in terms of its structural characteristics. culturing Komagataeibacter xylinus CGMCC 2955, BC structure changes with alterations in oxygen tension. Here, the K. xylinus CGMCC 2955 transcriptome was analyzed under different oxygen tensions. Transcriptome and genome analysis indicated that BC structure is related to the rate of BC synthesis and cell growth, and galU is an essential gene that controls the carbon metabolic flux between the BC synthesis pathway and the pentose phosphate (PP) pathway. The CRISPR interference (CRISPRi) system was utilized in K. xylinus CGMCC 2955 to control the expression levels of galU. By overexpressing galU and interfering with different sites of galU sequences using CRISPRi, we obtained strains with varying expression levels of galU (3.20-3014.84%). By testing the characteristics of BC, we found that the porosity of BC (range: 62.99-90.66%) was negative with galU expression levels. However, the crystallinity of BC (range: 56.25-85.99%) was positive with galU expression levels; galU expression levels in engineered strains were lower than those in the control strains. Herein, we propose a new method for regulating the structure of BC to provide a theoretical basis for its application in different fields.

Probiotics protect against tenofovir-induced mandibular bone loss in mice by rescuing mandible-derived mesenchymal stem cell proliferation and osteogenic differentiation.

BACKGROUND: Tenofovir disoproxil fumarate (TDF), a primary antiretroviral agent used to treat AIDS, triggers systematic bone loss. However, the effect of TDF on osteopenia or osteoporosis in the jaw remains unclear. TDF-induced bone loss in the jaw, if any, likely involves mandible-derived mesenchymal stem cells (MMSCs), which play a key role in jawbone metabolism. Probiotics prevent long bone loss, and could prove efficacious in treating TDF-induced mandibular bone loss. OBJECTIVES: To determine whether TDF triggers mandibular bone loss, elucidate the underlying mechanisms, and study the effect of Lactobacillus rhamnosus GG (LGG) on TDF-induced bone loss in the jaw. METHODS: Tenofovir disoproxil fumarate was administered orally daily and LGG semiweekly from eight weeks to the end of the study (LGG group) to male C57BL6/J mice. The mice were sacrificed, and body weight (BW) and serum Ca and P were measured. Mandibular histomorphometry was evaluated by micro-CT. MMSCs and LGG culture supernatants were isolated, and MMSC proliferation and ALP production when treated with different concentrations of LGG supernatant and/or TDF were measured. Relative abundance of osteogenic markers was assessed by qPCR. RESULTS: Orally administered LGG protected against bone mass loss and deterioration of bone microarchitecture and increased serum P levels. The BW of the TDF group was highest among the study groups. TDF partially impaired osteogenesis and proliferation of MMSCs. LGG culture supernatant rescued MMSC osteogenesis and proliferation, and osteogenic gene expression. CONCLUSIONS: Lactobacillus rhamnosus GG protected against tenofovir-induced mandibular bone loss in mice by rescuing MMSC proliferation and osteogenesis.

Application of Antimicrobial Polymers in the Development of Dental Resin Composite.

Dental resin composites have been widely used in a variety of direct and indirect dental restorations due to their aesthetic properties compared to amalgams and similar metals. Despite the fact that dental resin composites can contribute similar mechanical properties, they are more likely to have microbial accumulations leading to secondary caries. Therefore, the effective and long-lasting antimicrobial properties of dental resin composites are of great significance to their clinical applications. The approaches of ascribing antimicrobial properties to the resin composites may be divided into two types: The filler-type and the resin-type. In this review, the resin-type approaches were highlighted. Focusing on the antimicrobial polymers used in dental resin composites, their chemical structures, mechanical properties, antimicrobial effectiveness, releasing profile, and biocompatibility were included, and challenges, as well as future perspectives, were also discussed.

Oral cavity contains distinct niches with dynamic microbial communities.

Microbes colonize human oral surfaces within hours after delivery. During postnatal development, physiological changes, such as the eruption of primary teeth and replacement of the primary dentition with permanent dentition, greatly alter the microbial habitats, which, in return, may lead to community composition shifts at different phases in people's lives. By profiling saliva, supragingival and mucosal plaque samples from healthy volunteers at different ages and dentition stages, we observed that the oral cavity is a highly heterogeneous ecological system containing distinct niches with significantly different microbial communities. More importantly, the phylogenetic microbial structure varies with ageing. In addition, only a few taxa were present across the whole populations, indicating a core oral microbiome should be defined based on age and oral niches.

[Application of molecularly imprinted technology for separation of PGG from Guizhi Fuling capsule].

1,2,3,4,6-penta-O-galloyl-D-glucose (PGG) is one of the main active compounds of Guizhi Fuling capsule. Molecularly imprinted polymers (MIP) have high affinity toward template molecules synthesized by molecularly imprinted technology for its specific combined sites, which can overcome the shortcoming of traditional separation methods, such as complex operation, low efficiency, using large quantity of solvent and environmental pollution. In this paper, surface molecularly imprinted polymer (SMIP) was prepared by surface imprinting with PGG as the template molecule. Its adsorption capacity was measured by the scatchard equation. The separation of PGG from Guizhi Fuling capsule at preparatived scale was achieved with molecularly imprinted polymer as stationary phase and the purity was 90.2% by HPLC. This method can be used to prepare PGG from Guizhi Fuling capsule with large capacity and is easy to operate. It provides a new method for efficient separation and purification for other natural products.

[Chemical constituents of Tamarix chinensis].

OBJECTIVE: To study the chemical consistuents of Tamarix chinensis. METHODS: The compounds were isolated and purified by column chromatography and their structures were elucidated through spectroscopic analysis. RESULTS: Nine compounds were isolated and identified as isotamarixen(1), matairesinol(2), tetepathine(3), kaempferol(4), 4'-methylkaempferol(5),4',7-dimethylkaempferol (6), hexacosyl-3-caffeate(7), ferulic acid(8) and 3-methoxyl methyl gallate(9). CONCLUSION: Compounds 1-3,7 and 8 are isolated from this plant for the first time, compounds 1-3,7 are isolated from Tamarix genus for the first time.

Healing of acute alveolar bone dehiscence following treatment with porous biphasic calcium phosphate in beagle dogs.

The purpose of the present study was to evaluate histologically in beagle dogs the healing in acute dehiscence type defects following treatment with open flap debridement (OFD) with or without porous biphasic calcium phosphate (PBCP). Alveolar bone dehiscence defects were surgically created bilaterally at the labial aspects of maxillary third incisors in 12 beagle dogs. After root conditioning with ethylenediaminetetraacetate, PBCP was filled in the defects and the contralaterals were cured with OFD. Two fluorochrome labelings were administered at the 7th and 11th weeks, respectively. Four dogs were killed at the 12, 16, and 24 weeks, respectively. Histological observations were processed through microcomputed tomographic imaging, fluorescence microscope, and light microscopy. The formation of new regenerated tissues was assessed histomorphometrically. The results revealed the healing after treatments with PBCP evidenced a new attachment apparatus and that with OFD supported periodontal repair. In PBCP groups, the amount of new bone varied from 1.15 to 3.86 mm (23-77.2% of the original defect size), while only 0.3 to 1.04 mm (6-20.8%) in OFD group. The amount of new cementum in PBCP varied from 1.18 to 4.16 mm (23.6-82.3%), while only 0.67 to 1.15 mm (13.4-23%) in OFD group. The amount of periodontal ligament in PBCP varied from 1.03 to 4.12 mm (20.6-82.4%), while only 0 to 0.93 mm (0-18.6%) in OFD group. There was significantly more regenerated tissue in PBCP groups compared to OFD procedures (p < 0.01). The present results indicate that PBCP may enhance periodontal regeneration in acute-type labial dehiscence defects.

Formulation and evaluation of celastrol-loaded liposomes.

The main purpose of this study was to evaluate the intestinal absorption and the antineoplastic effect of the poorly water-soluble drug celastrol when liposomes were used as oral drug delivery system. Liposomes were prepared by the ethanol-injection method. An optimized liposome formulation composed of phospholipid, cholesterol and Tween-80 resulted in favorable encapsulation efficiency at 98.06 ± 0.94%. Homogeneous and stable particle size of 89.6 ± 7.3 nm and zeta potential of -(87.7 ± 5.8) mV were determined by laser particle size analyzer. Subsequently, the four-site perfusion rat intestinal model revealed that celastrol-loaded liposomes had improved effective permeability compared to the free drug in four intestinal segments (p < 0.05). Moreover, celastrol-loaded liposomes could also inhibit the tumor growth in C57BL/6 mice. These results suggest that liposomes could be a promising perioral carrier for celastrol.

Rheological and Mechanical Properties of Resin-Based Materials Applied in Dental Restorations.

Resin-based materials have been prevalent for dental restorations over the past few decades and have been widely used for a variety of direct and indirect procedures. Typically, resin-based dental materials are required to be flowable or moldable before setting and can provide adequate mechanical strength after setting. The setting method may include, but is not limited to, light-curing, self-curing or heating. In this review, based on different indications of resin-based dental materials (e.g., dental filling composite, dental bonding agent, resin luting cement), their rheological and mechanical properties were reviewed. Viscous and flexible properties were focused on for materials before setting, while elastic properties and mechanical strength were focused on for materials after setting. At the same time, the factors that may affect their rheological and mechanical properties were discussed. It is anticipated that the insightful information and prospections of this study will be useful to the future development and fabrication of resin-based dental restorative materials.

Pullout strength of miniscrews placed in anterior mandibles of adult and adolescent dogs: a microcomputed tomographic analysis.

INTRODUCTION: Miniscrews often loosen during orthodontic treatment, especially in teenage patients. The purposes of this study were to explore the differences of the pullout strengths of miniscrews placed in the anterior mandibles of adolescent and adult dogs and the structural parameters of peri-miniscrew bone, and to analyze the correlation between the pullout strengths and the variables of the peri-miniscrew bone structure. METHODS: Eight adult beagles and 8 young beagles with early permanent dentitions were used as experimental subjects. Two miniscrews were symmetrically placed in the anterior mandible of each dog several minutes before death. The bone density, relative bone volume, and cortical bone thickness were evaluated by micro-computed tomography, and the pullout strength of the miniscrew was tested with a testing machine. Regression analyses were used to study the relationship between pullout strength and bone density, relative bone volume, and cortical bone thickness. RESULTS: The values of bone density, relative bone volume, cortical bone thickness, and pullout strength were 781.94 + or - 21.46 mg of hydroxyapatite per cubic centimeter, 0.62 + or - 0.33, 1.14 + or - 0.11 mm, and 218.40 + or - 24.50 N for the adult dogs; and 713.61 + or - 13.08 mg of hydroxyapatite per cubic centimeter, 0.57 + or - 0.20, 1.07 + or - 0.86 mm, and 130.82 + or - 2.20 N for the young dogs, respectively. All pairs of pullout force and bone structural parameters had significant correlation coefficients. The pullout force showed the strongest correlation with bone density and the weakest with cortical bone thickness. CONCLUSIONS: The values of bone density, relative bone volume, cortical bone thickness, and the pullout strength of the adult group were higher than those of the young group. Furthermore, bone density is more sensitive in terms of showing pullout force compared with relative bone volume and cortical bone thickness.

[Factors influencing clinical application of bulk-fill composite resin].

Bulk-fill composite resin are simple to operate, and they reduce polymerization shrinkage and microleakage compare to traditional resin-based composites. However, their clinical application could be affected by numerous factors, such as the material itself, light curing, placement techniques, storage condition, and preheating. This review aimed to summarize the definitions, classifications, indications, clinical properties, and influencing factors of the clinical application of bulk-fill resin-based composites and discuss the ways to improve their clinical effectiveness.

Macrophage phenotypic switch orchestrates the inflammation and repair/regeneration following acute pancreatitis injury.

BACKGROUND: Impaired or hyperactive pancreas regeneration after injury would cause exocrine insufficiency or recurrent / chronic pancreatitis and potentially carcinogenesis. Macrophages are the most abundant immune cells in the regenerative pancreas, however their phenotype and role remain poorly defined. METHOD: Using caerulein-induced acute pancreatitis (AP) model, we examined the dynamic landscape of pancreatic macrophages throughout the acute inflammation to regeneration phases by flow cytometric and RNA-seq analyses. Liposome depletion of macrophages, Il4ra-/- mice as well as inhibitors were used to elucidate the role and regulatory mechanism of macrophages during pancreatic regeneration. FINDINGS: We found that M1 macrophages dominated in the pro-inflammatory phase of AP, while M2-like macrophages dominated during pancreas repair/regeneration. Depletion of macrophages at early or late regenerative stage dramatically blocked the acinar-ductal metaplasia (ADM) or delayed inflammation resolution, respectively. Moreover, alternative activation of macrophages was partially dependent on IL-4RA signaling, and ECM/AKT activation in pancreatic macrophages facilitated inflammation resolution during tissue regeneration. INTERPRETATION: Our findings illustrate a dynamic phenotype and function of macrophages during AP repair/regeneration, helping us better understand the mechanism of pancreatic regeneration and providing clues for novel therapeutic strategy.

Phenylpropanoid Derivatives Are Essential Components of Sporopollenin in Vascular Plants.

The outer wall of pollen and spores, namely the exine, is composed of sporopollenin, which is highly resistant to chemical reagents and enzymes. In this study, we demonstrated that phenylpropanoid pathway derivatives are essential components of sporopollenin in seed plants. Spectral analyses showed that the autofluorescence of Lilium and Arabidopsis sporopollenin is similar to that of lignin. Thioacidolysis and NMR analyses of pollen from Lilium and Cryptomeria further revealed that the sporopollenin of seed plants contains phenylpropanoid derivatives, including p-hydroxybenzoate (p-BA), p-coumarate (p-CA), ferulate (FA), and lignin guaiacyl (G) units. The phenylpropanoid pathway is expressed in the tapetum in Arabidopsis, consistent with the fact that the sporopollenin precursor originates from the tapetum. Further germination and comet assays showed that this pathway plays an important role in protection of pollen against UV radiation. In the pteridophyte plant species Ophioglossum vulgatum and Lycopodium clavata, phenylpropanoid derivatives including p-BA and p-CA were also detected, but G units were not. Taken together, our results indicate that phenylpropanoid derivatives are essential for sporopollenin synthesis in vascular plants. In addition, sporopollenin autofluorescence spectra of bryophytes, such as Physcomitrella and Haplocladium, exhibit distinct characteristics compared with those of vascular plants, indicating the diversity of sporopollenin among land plants.

Laser ultrasonic surface wave dispersion technique for non-destructive evaluation of human dental enamel.

This paper describes a novel optical system for clinical diagnosis of dental enamel based on its elasticity. Current examination techniques are typically destructive, and frequently impractical for in-vivo inspection. This paper describes the first application of a laser ultrasonic non-destructive evaluation (NDE) method for clinical dental diagnosis. It performs remote elasticity evaluation on small dimension samples. A focused laser line-source generates broadband surface acoustic wave (SAW) impulses which are detected with a simplified optical fibre interferometer. The measured SAW velocity dispersion spectrum was in turn used to characterise the elasticity of the specimen. Different metal structures were measured to verify the system performance. The results agree well with theoretical values and confirm the reliability and accuracy of the laser NDE system. This technique was then applied to evaluate the surface of sound natural human dental enamel. The measured dispersion spectra match theoretical expectations and the influences of both the enamel and the underlying dentin on the surface wave propagation were observed. This is the first time, to the best of our knowledge, that a laser based SAW velocity dispersion technique has been successfully applied on human dental enamel. As a remote, non-destructive technique it is applicable in-vivo and opens the way for early diagnosis of dental caries.

[Effect of preheating on the properties of resin composite].

Resin composite, which is commonly used as a dental filling material, has some problems, such as poor wear resistance, polymerization shrinkage, and poor dentin marginal adaptability. Preheating of resin composite improves its pro-perties. This paper reviewed the effects of resin composite preheating on its monomer conversion, marginal microleakage, mechanical properties, and irritation on dental pulp.