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1.
Gastroenterology ; 162(4): 1183-1196, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34968454

RESUMO

BACKGROUND & AIMS: N6-methyladenosine (m6A) governs the fate of RNAs through m6A readers. Colorectal cancer (CRC) exhibits aberrant m6A modifications and expression of m6A regulators. However, how m6A readers interpret oncogenic m6A methylome to promote malignant transformation remains to be illustrated. METHODS: YTH N6-methyladenosine RNA binding protein 1 (Ythdf1) knockout mouse was generated to determine the effect of Ythdf1 in CRC tumorigenesis in vivo. Multiomic analysis of RNA-sequencing, m6A methylated RNA immunoprecipitation sequencing, YTHDF1 RNA immunoprecipitation sequencing, and proteomics were performed to unravel targets of YTHDF1 in CRC. The therapeutic potential of targeting YTHDF1-m6A-Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2) was evaluated using small interfering RNA (siRNA) encapsulated by lipid nanoparticles (LNP). RESULTS: DNA copy number gain of YTHDF1 is a frequent event in CRC and contributes to its overexpression. High expression of YTHDF1 is significantly associated with metastatic gene signature in patient tumors. Ythdf1 knockout in mice dampened tumor growth in an inflammatory CRC model. YTHDF1 promotes cell growth in CRC cell lines and primary organoids and lung and liver metastasis in vivo. Integrative multiomics analysis identified RhoA activator ARHGEF2 as a key downstream target of YTHDF1. YTHDF1 binds to m6A sites of ARHGEF2 messenger RNA, resulting in enhanced translation of ARHGEF2. Ectopic expression of ARHGEF2 restored impaired RhoA signaling, cell growth, and metastatic ability both in vitro and in vivo caused by YTHDF1 loss, verifying that ARHGEF2 is a key target of YTHDF1. Finally, ARHGEF2 siRNA delivered by LNP significantly suppressed tumor growth and metastasis in vivo. CONCLUSIONS: We identify a novel oncogenic epitranscriptome axis of YTHDF1-m6A-ARHGEF2, which regulates CRC tumorigenesis and metastasis. siRNA-delivering LNP drug validated the therapeutic potential of targeting this axis in CRC.


Assuntos
Neoplasias Colorretais , Regulação Neoplásica da Expressão Gênica , Adenosina/análogos & derivados , Adenosina/metabolismo , Animais , Carcinogênese/genética , Neoplasias Colorretais/patologia , Humanos , Lipossomos , Camundongos , Nanopartículas , RNA Interferente Pequeno , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Troca de Nucleotídeo Guanina Rho/genética , Fatores de Troca de Nucleotídeo Guanina Rho/metabolismo , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismo
2.
Chemistry ; 29(35): e202300629, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37057571

RESUMO

The development of low-cost and high-efficiency bifunctional catalysts is still a challenge for hydrogen production through overall water splitting. This paper reports the in-situ synthesis of C-doped MoS2 /CoP/MoO2 using bacterial cellulose (BC) as the reducing agent and the source of C and using BC (MoS2 /Co1.2 MoO4.2 ⋅ 1.2H2 O/BC) as the template. Heterogeneous structure for hydrogen evolution reaction (HER) and alkaline water electrolysis in a wide pH range. Due to the large number of defect sites caused by C doping and the synergy between these three active components (MoS2 , CoP and MoO2 ), the HER and oxygen evolution reaction (OER) activities of the catalyst have been greatly improved. Therefore, during HER, a small initial overpotential (27 mV) was achieved in 1.0 M KOH. In 0.5 M H2 SO4 , 0.1 M PBS and 1.0 M KOH, the current density reached 10 mA cm-2 at overpotentials of 123.4, 150, and 139 mV, respectively. For OER, an overpotential of 268 mV was required to achieve 10 mA cm-2 . The alkaline two-electrode device composed of C doped MoS2 /CoP/MoO2 delivers 10 mA cm-2 at a low potential of 1.51 V and can be easily driven by a single AA battery. This work provides a new design strategy of C doped ternary heterostructures for electrocatalysis and related energy applications.


Assuntos
Celulose , Molibdênio , Hidrogênio , Oxigênio , Proteínas Serina-Treonina Quinases , Água , Concentração de Íons de Hidrogênio
3.
Int J Mol Sci ; 24(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37108336

RESUMO

Nucleocapsid protein (N protein) is an appropriate target for early determination of viral antigen-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have found that ß-cyclodextrin polymer (ß-CDP) has shown a significant fluorescence enhancement effect for fluorophore pyrene via host-guest interaction. Herein, we developed a sensitive and selective N protein-sensing method that combined the host-guest interaction fluorescence enhancement strategy with high recognition of aptamer. The DNA aptamer of N protein modified with pyrene at its 3' terminal was designed as the sensing probe. The added exonuclease I (Exo I) could digest the probe, and the obtained free pyrene as a guest could easily enter into the hydrophobic cavity of host ß-CDP, thus inducing outstanding luminescent enhancement. While in the presence of N protein, the probe could combine with it to form a complex owing to the high affinity between the aptamer and the target, which prevented the digestion of Exo I. The steric hindrance of the complex prevented pyrene from entering the cavity of ß-CDP, resulting in a tiny fluorescence change. N protein has been selectively analyzed with a low detection limit (11.27 nM) through the detection of the fluorescence intensity. Moreover, the sensing of spiked N protein from human serum and throat swabs samples of three volunteers has been achieved. These results indicated that our proposed method has broad application prospects for early diagnosis of coronavirus disease 2019.


Assuntos
COVID-19 , Polímeros , Humanos , Polímeros/química , SARS-CoV-2 , Fluorescência , COVID-19/diagnóstico , Pirenos/química
4.
J Prosthet Dent ; 130(3): 288-294, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34887077

RESUMO

This technique report presents a novel method of digitally replicating a treatment denture and converting it into a definitive denture. The procedure accurately duplicates the appearance of the mucosal surface and border of the treatment dentures, mounts the jaw relation on a virtual articulator to arrange artificial teeth, and optimizes the occlusion based on recorded mandibular motion tracks. This technique uses personalized jaw relation transfer and dynamic occlusal adjustment to establish balanced occlusion, which accomplishes the digital duplication of the treatment denture with high accuracy and minimal effort.


Assuntos
Prótese Total , Ajuste Oclusal , Fluxo de Trabalho , Planejamento de Dentadura/métodos , Oclusão Dentária , Articuladores Dentários , Registro da Relação Maxilomandibular/métodos
5.
Compr Rev Food Sci Food Saf ; 20(2): 1910-1936, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33438299

RESUMO

As emerging membrane technologies, forward osmosis (FO) and membrane distillation (MD), which work with novel driving forces, show great potential for liquid food concentration, owing to their low fouling propensity and great driving force. In the last decades, they have attracted the attention of food industry scientists in global scope. However, discussions of the FO and MD in liquid food concentration advancement, membrane fouling, and economic assessment have been scant. This review aims to provide an up-to-date knowledge about liquid food concentration by FO and MD. First, we introduce the principle and applications of FO and MD in liquid food concentration, and highlight the effect of process on liquid food composition, membrane fouling mechanism, and strategies for fouling mitigation. Besides, economic assessment of FO and MD processes is reviewed. Moreover, the challenges as well as future prospects of FO and MD applied in liquid food concentration are proposed and discussed. Comparing with conventional membrane-based or thermal-based technologies, FO and MD show outstanding advantages in high concentration rate, good concentrate quality, low fouling propensity, and low cost. Future efforts for liquid food concentration by FO and MD include (1) development of novel FO draw solution (DS); (2) understanding the effects of liquid food complex compositions on membrane fouling in FO and MD concentration process; and (3) fabrication of novel membranes and innovation of membrane module and process configuration for liquid food processing.


Assuntos
Destilação , Purificação da Água , Membranas Artificiais , Osmose
6.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(4): 369-372, 2021 Apr 10.
Artigo em Zh | MEDLINE | ID: mdl-33834468

RESUMO

OBJECTIVE: To explore the genetic basis for a neonate with Pierre-Robin sequence. METHODS: The child was subjected to chromosomal karyotyping, single nucleotide polymorphism array (SNP-array)-based comparative genomic hybridization and fluorescence in situ hybridization (FISH) analysis. RESULTS: The child has featured microgthnia, glossoptosis, upper airway obstruction, mandible dehiscence and short neck. He was found to have a karyotype of 46,XY,der(4)add(4)(q34). Her mother's karyotype was determined as 46,XX,t(1;4)(q43;q34), while his father was 46,XY. SNP-array analysis suggested the child to be arr [hg19] 1q42.2q44 (232 527 958-249 202 755)× 3; 4q34.3q35.2 (168 236 901-190 880 409)× 1. The result of SNP-array for both parents was normal. FISH analysis confirmed that his mother has carried a balanced t(1;4)(q42;34) translocation. The aberrant chromosome 4 in the child has derived from his mother's translocation, which gave rise to partial 1q trisomy and 4q monosomy. CONCLUSION: The 1q42.2q44 duplication and 4q34.3q35.2 deletion of the child probably underlay his abnormal phenotype of Pierre-Robin sequence.


Assuntos
Síndrome de Pierre Robin , Trissomia , Criança , Hibridização Genômica Comparativa , Feminino , Humanos , Hibridização in Situ Fluorescente , Recém-Nascido , Masculino , Monossomia , Síndrome de Pierre Robin/genética , Translocação Genética , Trissomia/genética
7.
Nano Lett ; 19(3): 2128-2137, 2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30799620

RESUMO

Gallium and gallium-based alloys, typical types of liquid metals with unique physiochemical properties, are emerging as a next generation of functional materials in versatile biomedical applications. However, the exploration of their biomedical performance is currently insufficient, and their intrinsic low oxidative resistance is a key factor blocking their further clinical translation. Herein, we report on the surface engineering of liquid metal-based nanoplatforms by an inorganic silica nanoshell based on a novel but facile sonochemical synthesis for highly efficient, targeted, and near-infrared (NIR)-triggered photothermal tumor hyperthermia in the NIR-II biowindow. The inorganic silica-shell engineering of liquid metal significantly enhances the photothermal performance of the liquid metal core as reflected by enhanced NIR absorption, improved photothermal stability by oxidation protection, and abundant surface chemistry for surface-targeted engineering to achieve enhanced tumor accumulation. Systematic in vitro cell-level evaluation and in vivo tumor xenograft assessment demonstrate that (Arg-Gly-Asp) RGD-targeted and silica-coated nanoscale liquid metal substantially induces phototriggered cancer-cell death and photothermal tumor eradication, accompanied by high in vivo biocompatibility and easy excretion out of the body. This work provides the first paradigm for surface-inorganic engineering of liquid metal-based nanoplatforms for achieving multiple desirable therapeutic performances, especially for combating cancer.


Assuntos
Hipertermia Induzida/métodos , Nanoconchas/química , Neoplasias/terapia , Estresse Oxidativo/efeitos dos fármacos , Ligas/síntese química , Ligas/química , Ligas/farmacologia , Gálio/química , Gálio/farmacologia , Humanos , Compostos Inorgânicos/química , Líquidos Iônicos/química , Líquidos Iônicos/uso terapêutico , Nanoconchas/uso terapêutico , Dióxido de Silício/química
8.
Environ Sci Technol ; 53(8): 4371-4379, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30888808

RESUMO

This study reports a novel intrabridging strategy to improve the antifouling performance of a thin-film composite (TFC) membrane. We demonstrate that the addition of Ca2+ during the interfacial polymerization reaction led to the formation of stable Ca2+-carboxyl complexes within the polyamide rejection layer. This intrabridging of carboxyl groups by Ca2+ effectively sequestrated them, reducing their availability for binding divalent metal ions in the aqueous solution and for forming foulant-metal-membrane interbridges. Membrane fouling and cleaning experiments confirmed improved flux stability and fouling reversibility for the Ca2+ modified membranes. The greatly enhanced antifouling performance of these membranes, together with their better surface hydrophilicity and greater water permeability, makes the intrabridging approach highly attractive in overcoming the classical permeability-selectivity-antifouling trade-off. Our findings pave a new direction for synthesizing high-performance TFC membranes.


Assuntos
Cálcio , Membranas Artificiais , Nylons , Osmose , Polimerização
9.
Small ; 14(35): e1800708, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30070076

RESUMO

Inorganic nanocarriers have shown their high performance in disease theranostics in preclinical animal models and further great prospects for clinical translation. However, their dissatisfactory biodegradability and pre-drug leakage with nonspecificity to lesion sites significantly hinders the possible clinical translation. To solve these two critical issues, a framework-engineering strategy is introduced to simultaneously achieve enhanced biodegradability and controllable drug releasing, based on the mostly explored mesoporous silica-based nanosystems. The framework of mesoporous silica is engineered by direct Mg doping via a generic dissolution and regrowth approach, and it can transform into the easy biodegradation of magnesium silicate nanocarriers with simultaneous on-demand drug release. Such magnesium silicate nanocarriers can respond to the mild acidic environment of tumor tissue, causing the fast breaking up and biodegradation of the silica framework. More interesting, the released Mg2+ can further activate Mg2+ -dependent DNAzyme on the surface of hollow mesoporous magnesium silicate nanoparticles (HMMSNs) to cleave the RNA-based gatekeeper, which further accelerates the release of loaded anticancer drugs. Therefore, enhanced anticancer efficiency of chemotherapeutic drugs assisted by the biodegradable intelligent HMMSNs is achieved. The high biocompatibility of nanocarriers and biodegradation products is demonstrated and can be easily excreted via feces and urine guaranteeing their further clinical translation.


Assuntos
DNA Catalítico/metabolismo , Tratamento Farmacológico , Magnésio/química , Dióxido de Silício/química , Animais , Antineoplásicos/farmacologia , Soluções Tampão , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Camundongos Endogâmicos BALB C , Camundongos Nus , Nanopartículas/química , Nanopartículas/ultraestrutura , Polietilenoglicóis/química , Porosidade , Soluções
10.
J Am Chem Soc ; 139(45): 16235-16247, 2017 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-29063760

RESUMO

Conventionally, ceramics-based materials, fabricated by high-temperature solid-phase reaction and sintering, are preferred as bone scaffolds in hard-tissue engineering because of their tunable biocompatibility and mechanical properties. However, their possible biomedical applications have rarely been considered, especially the cancer phototherapeutic applications in both the first and second near-infrared light (NIR-I and NIR-II) biowindows. In this work, we explore, for the first time as far as we know, a novel kind of 2D niobium carbide (Nb2C), MXene, with highly efficient in vivo photothermal ablation of mouse tumor xenografts in both NIR-I and NIR-II windows. The 2D Nb2C nanosheets (NSs) were fabricated by a facile and scalable two-step liquid exfoliation method combining stepwise delamination and intercalation procedures. The ultrathin, lateral-nanosized Nb2C NSs exhibited extraordinarily high photothermal conversion efficiency (36.4% at NIR-I and 45.65% at NIR-II), as well as high photothermal stability. The Nb2C NSs intrinsically feature unique enzyme-responsive biodegradability to human myeloperoxidase, low phototoxicity, and high biocompatibility. Especially, these surface-engineered Nb2C NSs present highly efficient in vivo photothermal ablation and eradication of tumor in both NIR-I and NIR-II biowindows. This work significantly broadens the application prospects of 2D MXenes by rationally designing their compositions and exploring related physiochemical properties, especially on phototherapy of cancer.


Assuntos
Materiais Biocompatíveis/uso terapêutico , Hipertermia Induzida/métodos , Neoplasias/terapia , Nióbio/uso terapêutico , Fototerapia/métodos , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Raios Infravermelhos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Nanoestruturas/uso terapêutico , Nanoestruturas/ultraestrutura , Neoplasias/patologia
11.
Clin Oral Investig ; 20(9): 2379-2386, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26809432

RESUMO

OBJECTIVES: The objective of this study was to evaluate the effect of gamma irradiation on the wear behavior of human tooth dentin in terms of possible alterations in crystallinity, grain size, and composition. MATERIALS AND METHODS: Human premolars (n = 19) were collected to obtain the perpendicular or parallel to the direction of the dentin tubule specimens. Each specimen was subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The nanoscratch tests were conducted. The scratch traces were observed via scanning electron microscope (SEM) and surface profilometer. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to investigate the alteration of crystallography and chemical composition of dentin after irradiation. The change of surface microhardness (SMH) was also evaluated. RESULTS: The nanoscratch results showed that the friction coefficient of dentin after irradiation became higher, and the depths and widths of scratch were greater than that of dentin before irradiation. Additionally, irradiation decreased the crystallinity of dentin and induced the formation of bigger crystals. The carbonate/mineral ratio was increased. Furthermore, a significant reduction in microhardness after irradiation was observed. The main damage mechanisms consisted of the formation of delamination and crack in both the specimens cut perpendicular and parallel to tubule dentin after irradiation. CONCLUSION: Irradiation affected directly the wear behavior of tooth dentin, accompanied by the alterations in crystallography, chemical composition, and surface microhardness of dentin. CLINICAL RELEVANCE: This would help extend understanding the influence of irradiation on dentin and provide suggestions for selecting more suitable materials for irradiated tooth.


Assuntos
Dente Pré-Molar/efeitos da radiação , Dentina/efeitos da radiação , Raios gama , Desgaste dos Dentes/etiologia , Adolescente , Cristalização , Dentina/química , Dureza , Humanos , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X , Adulto Jovem
12.
Bioresour Technol ; 393: 130013, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37956947

RESUMO

Currently, severe membrane fouling and inefficient nitrogen removal were two main issues that hindered the sustainable operation and further application of membrane bioreactor (MBR). This study aimed to simultaneously alleviate membrane fouling and improve nitrogen removal by applying high sludge concentration in MBR. Results showed that high sludge concentration (12000 mg/L) enhanced total nitrogen removal efficiency (78 %) and reduced transmembrane pressure development rate. Microbial community analysis revealed that high sludge concentration enriched functional bacteria associated with nitrogen removal, increased filamentous bacteria fraction in bio-cake and inhibited Thiothrix overgrowth in bulk sludge. From molecular level, the key genes involved in nitrogen metabolism, electron donor/adenosine triphosphate production and amino acid degradation were up-regulated under high sludge concentration. Overall, high sludge concentration improved microbial assembly and functional gene abundance, which not only enhanced nitrogen removal but also alleviated membrane fouling. This study provided an effective strategy for sustainable operation of MBR.


Assuntos
Incrustação Biológica , Esgotos , Esgotos/microbiologia , Nitrificação , Incrustação Biológica/prevenção & controle , Desnitrificação , Metagenoma , Reatores Biológicos/microbiologia , Nitrogênio , Membranas Artificiais
13.
Heliyon ; 10(1): e23283, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38205291

RESUMO

Objectives: To investigate the effect of different designs of movable parts and prosthetic materials on the stress distribution of supporting tissues in mandibular free end dentition defects using three-dimensional finite element analysis of digital Roach attachments. Material and methods: A 3D model of a patient with Kennedy class I mandibular edentulous conditions was generated, and twelve prosthesis models were applied, combining two designs of removable parts and six types of CAD/CAM restorative materials with different elastic modulus (conventional zirconia, ultra-translucent zirconia, Polyetheretherketone (PEEK), Lithium disilicate, Nanoceramic resin, and resin composite (Paradigm MZ100, 3 M ESPE)). The stress distribution of abutment periodontal ligament, edentulousmucosa, and junction of attachment were analyzed using finite element analysis. Results: The stress value of the buccal neck of the periodontal ligament and the maximum compressive stress of the distal periodontal ligament of the design with clasp arms were higher than those without clasp arms, while the stress on the junction of attachment and the displacement of the mucosa in the edentulous area were smaller. Restorative materials with high elastic modulus, such as conventional zirconia and ultra-translucent zirconia, are recommended to be used as the fixed part of Roach attachment. Conclusion: CAD/CAM Roach attachments with clasp arms are recommended for the protection of mucosal soft tissue. Restorative materials with high elastic modulus, such as conventional zirconia and ultra-translucent zirconia, are recommended as the fixed part of Roach attachment for patients with free end defect of mandibular dentition. Clinical significance: This study provides references for the design with clasp arms and the selection of clinical fixed-movable prosthetic materials. Clinicians should consider the design of attachments and selection of appropriate manufacturing materials carefully to avoid negative impacts on patients' periodontal support tissues.

14.
Carbohydr Polym ; 334: 122066, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38553206

RESUMO

Most current flexible electronic devices are based on petroleum materials that are difficult to degrade. The exploration of sustainable and eco-friendly materials has become a major focus in both the scientific and industrial communities. In this study, BC-Zn-BIM (bacterial cellulose-Zn-benzimidazole), a novel composite electrode material based on biodegradable BC was developed. Here, BC acted as a conductive medium involved in the conductive behavior of the composite material. We've explored the charge transport mechanisms of BC-Zn-BIM by density functional theory (DFT) calculations, and applied it in the electrochemical detection of Bisphenol A (BPA). The results indicated that the oxygen-containing groups in BC and the nitrogen-containing heterocycles in BIM have a tendency to lose electrons, whereas zinc ions actively acquire electrons from these groups. This process promoted charge transfer within BC-Zn-BIM and endowed it with semiconductor-like properties, enhancing the electrocatalytic reaction of BPA. The detection limit of the electrochemical biosensor was 12 nM, and the sample recovery was 95.1%105.6%. This study clarified the mechanism of the higher electrical properties achieved in Zn-BIM complex grown in-situ on dielectric BC. This will further promote the development of low-cost, environmentally friendly flexible electronic devices.


Assuntos
Celulose , Zinco , Celulose/química , Bactérias
15.
Dent Mater ; 39(1): 25-40, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36456379

RESUMO

OBJECTIVES: To compare the impact-sliding wear of different CAD/CAM resin-ceramic materials and tooth enamel, and explore the corresponding wear damage mechanism. METHODS: Human tooth enamel (EN), Vita ENAMIC (Vita, VE), Lava Ultimate (3 M, LU), and GC CERASMART (GC, CS) were used in this study. The hardness, elastic modulus, and roughness values of the samples were measured. Further, impact-sliding wear tests were performed in a ball-on-flat configuration with spherical zirconia antagonists and the coefficients of friction (CoF) were recorded simultaneously. Additionally, a white light interferometer was used to determine the volume losses and scanning electron microscopy was used to observe the wear morphology of the wear scars and the damage feature in the vertical sections to clarify the damage mechanism during the impact-sliding wear test. RESULTS: EN exhibited the highest elastic modulus and CoF, followed by VE, LU, and CS. The hardness and roughness of EN and VE were similar and were higher than those of LU and CS. Throughout the wear tests, VE exhibited the highest volume loss, whereas CS exhibited the lowest. The wear damage characteristics of VE were similar to those of EN, displaying brittle fractures of inorganic substances and plastic deformation of organic substances in the impact part, exhibiting plough marks in the sliding parts. In the case of LU and CS, the entire wear areas displayed plastic deformation of the resin matrix, exfoliation of the filler particles, and plough marks. SIGNIFICANCE: Enamel and polymer-infiltrated ceramic network materials exhibit similar wear damage modes. Additionally, the high-density nanocomposite resin material is the most resistant to impact-sliding wear from a tribological perspective.


Assuntos
Cerâmica , Resinas Compostas , Humanos , Dureza , Desenho Assistido por Computador , Plásticos , Esmalte Dentário , Teste de Materiais , Propriedades de Superfície , Porcelana Dentária , Materiais Dentários
16.
Artigo em Inglês | MEDLINE | ID: mdl-36901568

RESUMO

Ceramic membrane has emerged as a promising material to address the membrane fouling issue in membrane bioreactors (MBR). In order to optimize the structural property of ceramic membrane, four corundum ceramic membranes with the mean pore size of 0.50, 0.63, 0.80, and 1.02 µm were prepared, which were designated as C5, C7, C13, and C20, respectively. Long-term MBR experiments showed that the C7 membrane with medium pore size experienced the lowest trans-membrane pressure development rate. Both the decrease and increase of membrane pore size would lead to more severe membrane fouling in the MBR. It was also interesting that with the increase of membrane pore size, the relative proportion of cake layer resistance in total fouling resistance was gradually increased. The content of dissolved organic foulants (i.e., protein, polysaccharide and DOC) on the surface of C7 was quantified as the lowest among the different ceramic membranes. Microbial community analysis also revealed the C7 had a lower relative abundance of membrane fouling associated bacteria in its cake layer. The results clearly demonstrated that ceramic membrane fouling in MBR could be effectively alleviated through optimizing the membrane pore size, which was a key structural factor for preparation of ceramic membrane.


Assuntos
Membranas Artificiais , Microbiota , Cerâmica , Reatores Biológicos/microbiologia , Bactérias , Esgotos
17.
Water Res ; 222: 118928, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35933819

RESUMO

Catalytic membrane can achieve sieving separation and advanced oxidation simultaneously, which can improve the effluent water quality while reducing membrane fouling. In this study, the catalytic membranes (M2+Al@AM) were fabricated by loading different binary layered metal oxides (M2+Al-LMO: MnAl-LMO, CuAl-LMO and CoAl-LMO) on alumina ceramic substrate membranes (AM) via vacuum filtration followed by calcination process. The performance of the catalytic membranes was investigated by filtering actual surface water. It was found that the presence of peroxymonosulfate (PMS) could mitigate membrane fouling effectively, as evidenced by the increase of normalized flux from 0.28 to 0.62 in CoAl@AM/PMS system, from 0.25 to 0.52 in CuAl@AM/PMS system, and from 0.22 to 0.31 in MnAl@AM/PMS system, respectively. Correspondingly, the CoAl@AM exhibited the highest removal for UV254, TOC and fluorescent components in the surface water, followed by CuAl@AM and MnAl@AM. Quenching effect of phenol and furfuryl alcohol proposed the surface-bound radicals and singlet oxygen were the major reactive oxygen species in the M2+Al@AM/PMS systems. Interface free energy calculations confirmed the in-situ PMS activation could enhance the repulsive interactions between NOM and the membranes, thus mitigating membrane fouling. This work provides an original but simple strategy for catalytic ceramic membrane preparation and new insights into the mechanism of membrane fouling mitigation in catalytic membrane system.


Assuntos
Purificação da Água , Cerâmica , Carvão Mineral , Membranas Artificiais , Óxidos , Peróxidos
18.
J Adhes Dent ; 24(1): 125-136, 2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35322950

RESUMO

PURPOSE: To evaluate the effects of different hydrofluoric acid (HF) concentrations and etching times on the surface topography, roughness, and resin bond strength to ceramic-coated zirconia (CC), and to compare them with the effects of alumina air-abrasion combined with 10-MDP (AA). MATERIALS AND METHODS: AA and CC specimens were divided into 12 groups (N = 10). The CC groups were etched with HF at different concentrations (5% or 9.5%) for various durations (0 min, 1 min, 2 min, 3 min, 5 min or 10 min). The surface morphology was analyzed using SEM. Energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) were performed for chemical and crystalline-phase analyses. Surface roughness (Ra) and shear bond strength (SBS) were recorded and statistically analyzed. RESULTS: The SBS of CC groups initially increased, but then decreased with etching time for both HF acid concentrations. The 9.5% HF group displayed more marked topographical changes and higher Ra compared with the 5% HF group for the same etching period. Mean SBS was lower in the AA group compared with the CC groups etched with 5% HF for 2-10 min and 9.5% HF for 1-3 min (p < 0.05). CONCLUSIONS: Different HF concentrations and etching times influenced the surface topography, roughness, and resin bond strength of/to ceramic-coated zirconia. Etching with 5% HF for 5 min and with 9.5% HF for 2 min, respectively, provided the highest SBS.


Assuntos
Colagem Dentária , Ácido Fluorídrico , Cerâmica , Colagem Dentária/métodos , Ácido Fluorídrico/química , Teste de Materiais , Propriedades de Superfície , Zircônio
19.
Eur Cell Mater ; 22: 12-25, 2011 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-21732279

RESUMO

Although in vivo studies have shown that low-magnitude, high-frequency (LMHF) vibration (LM: < 1 ×g; HF: 20-90 Hz) exhibits anabolic effects on skeletal homeostasis, the underlying cellular/molecular regulation involved in bone adaptation to LMHF vibration is little known. In this report, we tested the effects of microvibration (magnitude: 0.3 ×g, frequency: 40 Hz, amplitude: ± 50 µm, 30 min/12 h) on proliferation and osteodifferentiation of bone marrow-derived mesenchymal stromal cells (BMSCs) seeded on human bone-derived scaffolds. The scaffolds were prepared by partial demineralisation and deproteinisation. BMSCs were allowed to attach to the scaffolds for 3 days. Morphological study showed that spindle-shaped BMSCs almost completely covered the surface of bone-derived scaffold and these cells expressed higher ALP activity than those cultured on plates. After microvibration treatment, BMSC proliferation was decreased on day 7 and 10; however, numbers of genes and proteins expressed during osteogenesis, including Cbfa1, ALP, collagen I and osteocalcin were greatly increased. ERK1/2 activation was involved in microvibration-induced BMSC osteogenesis. Taken together, this study suggests that bone-derived scaffolds have good biocompatibility and show osteoinductive properties. By increasing the osteogenic lineage commitment of BMSCs and enhancing osteogenic gene expressions, microvibration promotes BMSC differentiation and increase bone formation of BMSCs seeded on bone-derived scaffolds. Moreover, ERK1/2 pathway plays an important role in microvibration-induced osteogenesis in BMSC cellular scaffolds.


Assuntos
Células-Tronco Mesenquimais/citologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/fisiologia , Osteogênese , Engenharia Tecidual/métodos , Vibração , Materiais Biocompatíveis , Células da Medula Óssea , Osso e Ossos , Diferenciação Celular , Ativação Enzimática , Perfilação da Expressão Gênica , Humanos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas/análise , Alicerces Teciduais , Vibração/uso terapêutico
20.
J Adhes Dent ; 23(5): 437-446, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34549927

RESUMO

PURPOSE: To evaluate the effects of airborne-particle abrasion and MDP (methacryloyloxydecyl dihydrogen phosphate)-based primer treatment on the strength of resin bonds to highly translucent zirconia. MATERIALS AND METHODS: Eight groups (n = 20 per group) of specimens were prepared with airborne-particle abrasion treatments (0.1-, 0.3-, or 0.6-MPa pressure) or not (untreated control) and MDP-based primer (treated) or not (untreated). Shear bond strength (SBS) tests were performed on the composite-to-ceramic bonded specimens either with or without thermocycling. After airborne-particle abrasion, the surface topography was evaluated by white light interferometry, and a phase analysis was conducted with x-ray diffraction (XRD). Surface roughness (Ra), surface energy (SE), and SBS measurements were statistically analyzed using either Tukey's HSD or the Kruskal-Wallis test, based on applicability. Lastly, the failure mode was observed by optical microscope and scanning electron microscope. RESULTS: Airborne-particle abrasion resulted in significantly larger Ra (p < 0.05), especially with higher treatment pressures. Treatment with MDP-based primer caused significantly higher SE and SBS than airborne-particle abrasion alone (p < 0.05), both with and without aging. CONCLUSION: MDP-based primer can enhance the bond strength and reduce hydrolytic aging of the bonded interface for highly translucent zirconia, exceeding the effects of airborne-particle abrasion. It is recommended that MDP-based primer treatment be applied with a composite cement containing adhesive phosphate monomer.


Assuntos
Colagem Dentária , Cimentos de Resina , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
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