RESUMO
BACKGROUND: Dental caries is one of the most preventable oral diseases among children in developing countries. This study aims to estimate the prevalence and severity of dental caries in the first permanent molar and analyze the related risk factors among sixth-grade students in São Tomé Island. METHODS: A cross-sectional study with a stratified cluster sampling method was conducted on 1855 sixth-grade school children, mainly aged 11 to 14 years old, from 10 schools in 6 regions of São Tomé Island, from April 17 to June 27, 2021. Dental caries examination was performed by using the CAST criteria (DMFT) index, and the self-administered questionnaires about family background, oral hygiene, and relevant behaviors were collected. Multivariable logistic regression was used to study risk factors related to dental caries ofâtheâfirstâpermanentâmolar, and all data analyses were done using SPSS version 25. RESULTS: The prevalence of dental caries inâtheâfirstâpermanentâmolarâwas 68.79%, without significant difference between gender, age, residence, and whetherâonly child or not. The mean Decayed, Missing, and Filled Teeth (DMFT) index and mean Decayed, Missing, and Filled Surface (DMFS) index were 1.751 ± 1.514 and 3.542 ± 3.941, respectively. The rate of filling teethâwas 5.50%, and Pit and Fissure Sealant (PFS) rate was 2.21%. The overall prevalence and DMFT index of dental caries of permanentâteeth was 76.01% and 2.753 ± 4.569, respectively. The results of logistic regression analysis indicated that the frequency of candy/chocolate consumption (OR = 1.095) and fair self-assessment of dental health (OR = 1.354) were significantly associated with dental caries (P < 0.05). CONCLUSIONS: The high prevalence of dental caries in the first permanent molar was a public health issue among sixth-grade school children in São Tomé Island. The prevalence of dental caries, mean DMFT and DMFS scores were higher, while the rate of filling and PFS teeth were lower than the average score of other African countries. Thus, oral health education,âimplement oral healthâpreachingâto school children and their parents is crucial to prevent dental caries.
Assuntos
Cárie Dentária , Adolescente , Criança , Estudos Transversais , Índice CPO , Cárie Dentária/epidemiologia , Humanos , Dente Molar , Prevalência , Fatores de Risco , EstudantesRESUMO
Enterovirus 71 (EV71) infection is generally associated with hand-foot-and-mouth disease (HFMD) and may cause severe neurological disorders and even death. An effective murine oral infection model for studying the pathogenesis of various clinical EV71 isolates is lacking. We developed a transgenic (Tg) mouse that expresses an EV71 receptor, that is, human scavenger receptor class B member 2 (hSCARB2), in a pattern highly similar to that of endogenous murine SCARB2 (mSCARB2) protein. A FLAG-tagged SCARB2 cDNA fragment composed of exons 3 to 12 was inserted into a murine Scarb2 gene-containing bacterial artificial chromosome (BAC) clone, and the resulting transgene was used for establishment of chimeric receptor-expressing Tg mice. Tg mice intragastrically (i.g.) infected with clinical isolates of EV71 showed neurological symptoms, such as ataxia and paralysis, and fatality. There was an age-dependent decrease in susceptibility to viral infection. Pathological characteristics of the infected Tg mice resembled those of encephalomyelitis in human patients. Viral infection was accompanied by microglial activation. Clodronate treatment of the brain slices from Tg mice enhanced viral replication, while lipopolysaccharide treatment significantly inhibited it, suggesting an antiviral role for microglia during EV71 infection. Taken together, this Tg mouse provides a model that closely mimics natural infection for studying EV71 pathogenesis and for evaluating the efficacy of vaccines or other antiviral drugs.IMPORTANCE The availability of a murine model of EV71 infection is beneficial for the understanding of pathogenic mechanisms and the development and assessment of vaccines and antiviral drugs. However, the lack of a murine oral infection model thwarted the study of pathogenesis induced by clinically relevant EV71 strains that are transmitted via the oral-oral or oral-fecal route. Our Tg mice could be intragastrically infected with clinically relevant EV71 strains in an efficient way and developed neurological symptoms and pathological changes strikingly resembling those of human infection. Moreover, these mice showed an age-dependent change in susceptibility that is similar to the human case. This Tg mouse, when combined with the use of other genetically modified mice, potentially contributes to studying the relationship between developmental changes in immunity and susceptibility to virus.
Assuntos
Antígenos CD36/metabolismo , Infecções por Enterovirus/genética , Proteínas de Membrana Lisossomal/metabolismo , Receptores Depuradores/metabolismo , Animais , Antígenos CD36/fisiologia , Linhagem Celular , Células Cultivadas , Modelos Animais de Doenças , Enterovirus/genética , Enterovirus/metabolismo , Enterovirus Humano A/genética , Infecções por Enterovirus/imunologia , Infecções por Enterovirus/virologia , Humanos , Proteínas de Membrana Lisossomal/fisiologia , Camundongos , Camundongos Transgênicos , Receptores Depuradores/genética , Receptores Depuradores/fisiologia , Receptores Virais/metabolismo , Replicação ViralRESUMO
We report a microfluidic paper based analytical device implementing ion concentration polarization (ICP) for rapid pre-concentration of Escherichia coli in water. The fabricated device consists of a paper channel with a Nafion® membrane and in-built micro wire electrodes to supply electric voltage to induce the ICP effect. E. coli cells were stained with SYTO 9 and fluorescence was used as a sensing method. The device achieved high concentration factor up to 2 × 105 within minutes. The effect of total ion concentration, on ICP and fluorescence intensity was studied. The reported device and method are suitable and effective for detection of E. coli during ballast water quality monitoring, coastal water quality monitoring where high salinity water is present.
Assuntos
Escherichia coli/isolamento & purificação , Técnicas Analíticas Microfluídicas , Microbiologia da Água , Eletrodos , Desenho de Equipamento , Polímeros de Fluorcarboneto/química , Íons/química , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Papel , Cloreto de Sódio/químicaRESUMO
An easy and objective way to evaluate mid-face sagging is marking straight lines between the nasal alar and the mandibular angle, one in the supine and the other in an upright position. The maximal distance between the two lines drawn is measured. Statistic analyses shows that this maximum distance demonstrates positive correlation with age and body mass index that reflects the level of mid-face sagging. This simple method may be utilised to evaluate the effect of anti-ageing treatment on the face in the context of mid-face sagging.
Assuntos
Antropometria/métodos , Bochecha/anatomia & histologia , Bochecha/fisiologia , Envelhecimento da Pele/fisiologia , Adulto , Idoso , Elasticidade/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Fenômenos Fisiológicos da Pele , Taiwan , Adulto JovemRESUMO
A controllable approach for preparing a portable colloidal photonic crystal (CPC) array chip is presented. The approach was inspired by the confinement effect of nanoparticle self-assembly on patterned surface. Hydrophobic polydimethylsiloxane substrate with reproducible micro-region array was fabricated by soft-lithography. The substrate was employed as the patterned template for self-assembly of monodisperse polystyrene nanoparticles. The CPC units can be prepared in several minutes, and exhibit consistent reflection wavelength. By adjusting the size of polystyrene nanoparticles and the shape of micro-regions, CPC units with multiple structure, colors and geometries were obtained. The CPC array chip features fluorescence enhancement owing to the optical modulation capability of the periodic nanostructure of the self-assembled CPC. With the reflection wavelength (523 nm) of green CPC units overlapping the emission wavelength (520 nm, with excitation wavelength of 490 nm) of 6-carboxyfluorescein-labeled DNA probe, the fluorescence intensity increased more than 10-fold. For signal-amplified assay of adenosine, the concentration range of linear response was 5.0 × 10-5 mol L-1 to 1.0 × 10-3 mol L-1, and the limit of detection was 1.3 × 10-6 mol L-1. Because of the enhancement effect of photonic crystal, the fluorescence images were more readable from the CPC array chip, compared with those from the planar substrate. The chip has potential applications in multiplex determination with high-throughput via encoding strategy based on the tunable structure, color or geometric shape. Graphical abstractSchematic diagram of signal-enhanced fluorescent detection of adenosine based on the colloidal photonic crystal array chip (PDMS, polydimethylsiloxane; PS NPs, polystyrene nanoparticles; CPC, colloidal photonic crystal; GO, graphene oxide; FAM, 6-carboxyfluorescein).
Assuntos
Adenosina/análise , Técnicas Biossensoriais/métodos , Fluoresceínas/química , Corantes Fluorescentes/química , Dispositivos Lab-On-A-Chip , Coloides , Cristalização , Sondas de DNA/química , Dimetilpolisiloxanos/química , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Fótons , Espectrometria de Fluorescência , Propriedades de SuperfícieRESUMO
The aim of this study is to explore the effects of Manganese addition and homogenization treatment on the microstructures and mechanical properties of the Al-7Mg-0.15Ti (B535.0) alloy. The optical microscopy, electrical conductivity measurements, transmission electron microscopy, scanning electron microscopy (SEM + EBSD), as well as Rockwell hardness and tensile tests, were exploited for this purpose. The main objectives are to refine the grain size, inhibit grain growth in the annealed state, and enhance the mechanical strength of the alloy. The results show that the addition of manganese to the Al-7Mg-0.15Ti alloys refined the as-cast and recrystallized grains of the alloys. During the homogenization process, Al4Mn high-temperature stable dispersoids were precipitated in the aluminum matrix. After annealing, the Al4Mn particles blocked the movement of grain boundaries during the growth of the recrystallized grains and inhibited grain growth. Consequently, the annealed alloys showed grain refinement and dispersion strengthening. The Al4Mn dispersoids of the alloys with manganese added were smaller and denser after a two-stage homogenization process compared to those that underwent a one-stage homogenization process. By contrast, for the alloys without the addition of manganese, the recrystallized grains showed normal growth after annealing, and different homogenization processes had no significantly different effects.
Assuntos
Ligas/química , Alumínio/química , Manganês/química , Titânio/química , Teste de Materiais , Estresse Mecânico , Propriedades de Superfície , Resistência à TraçãoRESUMO
BACKGROUND: RANKL and RANK play an important role in jaw resorption during the development of the ameloblastomas. Therefore, the aim of this study was to explore the effect of 99 Tc-MDP on OPG/RANKL/RANK system on RAW264.7 and MC3T3-E1 cell lines in vitro and provide the theoretical basis for the clinical treatment of the jaw ameloblastoma. METHODS: Different concentrations of 99 Tc-MDP were used to treat RAW264.7 and MC3T3-E1 cell lines. The cell proliferative inhibition rate was analyzed by CCK-8. Cell apoptosis and cell cycle were detected by flow cytometry. Western blot was used to detect the expression of OPG, RANKL, and RANK. RESULTS: Treatment of RAW264.7 cell lines with different concentrations of 99 Tc-MDP had inhibitory effects and decreased the expression of RANK protein. The cell proliferation of 99 Tc-MDP on MC3T3-E1 cell lines was stronger at 48 hours than at 24 hours except for 100 µg/mL concentration group. Compared with the concentration of 0.01 µg/mL, the treatment of MC3T3-E1 cells with 100 µg/mL 99 Tc-MDP showed that the cell proliferative effect decreased at 24 hours and 48 hours (P < 0.05). After treatment with 0.01 µg/mL 99 Tc-MDP, the expression of OPG in MC3T3-E1 cells was significantly increased (P < 0.05). Compared with 0.01 µg/mL, the expression of RANKL was decreased after treatment with 100 µg/mL 99 Tc-MDP (P < 0.05). CONCLUSION: 99 Tc-MDP can induce apoptosis of RAW264.7 cells and inhibit the expression of RANK protein. The effect of 0.01 µg/mL of low concentration of 99 Tc-MDP can promote the proliferation of MC3T3-E1 cells and increase the expression of OPG and RANKL protein. 99 Tc-MDP may have adjuvant therapeutic effects on the treatment of jaw ameloblastoma.
Assuntos
Ameloblastoma/genética , Ameloblastoma/patologia , Reabsorção Óssea/genética , Expressão Gênica/efeitos dos fármacos , Neoplasias Maxilomandibulares/genética , Neoplasias Maxilomandibulares/patologia , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligante RANK/genética , Ligante RANK/metabolismo , Compostos Radiofarmacêuticos/farmacologia , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Medronato de Tecnécio Tc 99m/farmacologia , Células 3T3 , Ameloblastoma/fisiopatologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular , Quimioterapia Adjuvante , Relação Dose-Resposta a Droga , Neoplasias Maxilomandibulares/fisiopatologia , Camundongos , Células RAW 264.7 , Compostos Radiofarmacêuticos/uso terapêutico , Medronato de Tecnécio Tc 99m/uso terapêuticoRESUMO
STATEMENT OF PROBLEM: The press-on-metal (PoM) technique has been used as an alternative fabrication method for metal-ceramic restorations. However, how the PoM technique compares with the conventional porcelain layering (CPL) technique under a variety of conditions is unclear. PURPOSE: The purpose of this in vitro study was to compare the bond strength of 3 alloy substrates with heat-pressed ceramics or conventionally layered porcelain before and after thermocycling. MATERIAL AND METHODS: Specimens (n=5) of Au, Pd, and Ni-Cr alloys were veneered with heat-pressed ceramics or conventionally layered porcelain. The 3-point bend test was conducted according to the International Organization for Standardization standard 9693-1 as bond strength before and after thermocycling. The metal-ceramic interfaces were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS). Two- and 3-way ANOVA followed by the Tukey honestly significant difference (HSD) test were used to analyze the data (α=.05). RESULTS: Significantly lower mean bond strength was recorded for the Au and Pd alloys of the PoM group than for those of the CPL group (P<.05). CPL-Au demonstrated the highest bond strength of 50.2 ±2.0 MPa, whereas PoM-Pd showed the lowest bond strength of 31.8 ±2.7 MPa; significant differences were found among all groups (P<.05). After 20 000 thermocycles, CPL-Au showed significantly reduced bond strength value (P<.05). A value of approximately 40 MPa was observed in all groups except for PoM-Pd (26.5 ±1.6 MPa, P<.05). The metal-ceramic interface resulting from the PoM technique revealed 2- to 20-µm pores, with more defects observed in the PoM-Pd group than in any of the other group. CONCLUSIONS: Defects and an oxide layer were formed at the metal-ceramic interface during the heat-pressing process, especially for the Pd alloy. After thermocycling, PoM-Pd had the lowest bond strength value, although it exceeded the minimum 25 MPa of the ISO 9693-1 standard. The Au and Ni-Cr alloys exhibited similar levels of porcelain bond strength with both techniques.
Assuntos
Ligas Dentárias , Colagem Dentária , Cerâmica , Ligas de Cromo , Porcelana Dentária , Temperatura Alta , Teste de Materiais , Ligas Metalo-Cerâmicas , Propriedades de SuperfícieRESUMO
This study demonstrated the application of transmasseteric anterior parotid approach for open reduction of mandibular subcondylar fractures depending on the basis of the anatomical study of the temporomandibular joint and parotid gland area. The anatomical study was performed on 5 Chinese adult cadavers fixed by 10% formalin. The temporomandibular joints and parotid regions were studied. In the clinical study, 26 patients with mandibular subcondylar fractures were recruited between July 2014 and December 2017. All 26 patients with mandibular subcondylar fractures received satisfactory occlusions and normal mouth opening: no postoperative facial paralysis occurred in these patients. It is crucial to know the anatomy of both temporomandibular joint and parotid region for reducing significantly the surgical trauma and complications. Transmasseteric anterior parotid approach is a feasible approach for the surgical treatment of the mandibular subcondylar fractures. This method can provide adequate exposure, minimal facial nerve injury, open reduction easily, and inconspicuous scarring.
Assuntos
Fixação Interna de Fraturas/métodos , Côndilo Mandibular/cirurgia , Fraturas Mandibulares/cirurgia , Adolescente , Adulto , Placas Ósseas , Feminino , Humanos , Masculino , Côndilo Mandibular/lesões , Adulto JovemRESUMO
Macroporous cryogels were prepared and used to deplete abundant proteins. It was accomplished based on the sample heterogeneity rather than any exogenous assistance. Human serum was added in monomer solutions to synthesize molecularly imprinted polymers; therein some abundant proteins were imprinted in the polyacrylamide cryogels. Meanwhile the rare components remained aqueous. Chromatography and electrophoresis showed that albumin, serotransferrin, and most globulins were depleted by columns packed with the molecularly imprinted polymers. After the depletion, lower abundance proteins were revealed by SDS-PAGE, peptide fingerprint analysis, and identified by MALDI-TOF-MS. This is an example that a "per se imprint" protocol enables to gradually dimidiate proteomes, simplify sample complexities, and facilitate further proteome profiling or biomarker discovery.
Assuntos
Proteínas Sanguíneas/química , Proteínas Sanguíneas/isolamento & purificação , Criogéis/química , Impressão Molecular/métodos , Polímeros/química , Soro/química , Eletroforese em Gel de Poliacrilamida , Humanos , Estrutura MolecularRESUMO
Enterovirus 71 (EV71) is the most virulent pathogen among enteroviruses that cause hand, foot and mouth disease in children but rarely in adults. The mechanisms that determine the age-dependent susceptibility remain largely unclear. Here, we found that the paucity of invariant natural killer T (iNKT) cells together with immaturity of the immune system was related to the susceptibility of neonatal mice to EV71 infection. iNKT cells were crucial antiviral effector cells to protect young mice from EV71 infection before their adaptive immune systems were fully mature. EV71 infection led to activation of iNKT cells depending on signaling through TLR3 but not other TLRs. Surprisingly, iNKT cell activation during EV71 infection required TLR3 signaling in macrophages, but not in dendritic cells (DCs). Mechanistically, interleukin (IL)-12 and endogenous CD1d-restricted antigens were both required for full activation of iNKT cells. Furthermore, CD1d-deficiency led to dramatically increased viral loads in central nervous system and more severe disease in EV71-infected mice. Altogether, our results suggest that iNKT cells may be involved in controlling EV71 infection in children when their adaptive immune systems are not fully developed, and also imply that iNKT cells might be an intervention target for treating EV71-infected patients.
Assuntos
Enterovirus Humano A/imunologia , Infecções por Enterovirus/imunologia , Imunidade Celular , Macrófagos/imunologia , Células T Matadoras Naturais/imunologia , Receptor 3 Toll-Like/fisiologia , Animais , Células Cultivadas , Infecções por Enterovirus/genética , Humanos , Imunidade Celular/genética , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Camundongos Knockout , Células T Matadoras Naturais/metabolismo , Transdução de Sinais/imunologiaRESUMO
The crystal structure of cellulose will directly affect the properties of bamboo fiber -reinforced composite, but the unit cell of native cellulose in bamboo has never been investigated. The most accepted model for the structure of native cellulose is Meyer-Misch model which provides a reference to understand the unit cell of native cellulose in bamboo. The native cellulose consists of two different crystal structures (â (α) and â (ß)) which exist in different plants with different proportions. Because of this situation, the crystal structure of bamboo cellulose should have a unique model. The moso bamboo (Phyllostachys edulis (Carr. ) H. de Lehaie)was selected. The crystal structure of cellulose of bamboo was investigated with two dimensional synchrotron radiation wide angle X-ray scattering (SR-WAXS). The values of the interplanar spacings of each peak were obtained from SR-WAXS patterns, and then crystal structure parameters were calculated according to monoclinic crystal system. The results show that the fibre axis of a bamboo cellulose unit cell with a monoclinic unit cell of a=8.35 Å, b (fiber axis)=10.38 Å, c=8.02 Å, ß=84.99°. This model has a two antiparallel arrangement for the chains in unit cell, with four glucose residues. Thus, the model may be used to provide a theoretical basis for high value-added bamboo fiber -reinforced composite.
Assuntos
Poaceae , Síncrotrons , Celulose , Radiografia , Espalhamento de Radiação , Raios XRESUMO
We investigated whether stem cells remember past physical signals and whether these can be exploited to dose cells mechanically. We found that the activation of the Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding domain (TAZ) as well as the pre-osteogenic transcription factor RUNX2 in human mesenchymal stem cells (hMSCs) cultured on soft poly(ethylene glycol) (PEG) hydrogels (Young's modulus E ~ 2 kPa) depended on previous culture time on stiff tissue culture polystyrene (TCPS; E ~ 3 GPa). In addition, mechanical dosing of hMSCs cultured on initially stiff (E ~ 10 kPa) and then soft (E ~ 2 kPa) phototunable PEG hydrogels resulted in either reversible or--above a threshold mechanical dose--irreversible activation of YAP/TAZ and RUNX2. We also found that increased mechanical dosing on supraphysiologically stiff TCPS biases hMSCs towards osteogenic differentiation. We conclude that stem cells possess mechanical memory--with YAP/TAZ acting as an intracellular mechanical rheostat--that stores information from past physical environments and influences the cells' fate.
Assuntos
Diferenciação Celular , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Osteogênese , Polietilenoglicóis/química , Aciltransferases , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Humanos , Células-Tronco Mesenquimais/citologia , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAPRESUMO
BACKGROUND: Xenobiotic chemicals with estrogenic activity (EA), such as bisphenol A (BPA), have been reported to have potential adverse health effects in mammals, including humans, especially in fetal and infant stages. Concerns about safety have caused many manufacturers to use alternatives to polycarbonate (PC) resins to make hard and clear, reusable, plastic products that do not leach BPA. However, no study has focused on whether such BPA-free PC-replacement products, chosen for their perceived higher safety, especially for babies, also release other chemicals that have EA. METHODS: We used two, well-established, mammalian cell-based, assays (MCF-7 and BG1Luc) to assess the EA of chemicals that leached into over 1000 saline or ethanol extracts of 50 unstressed or stressed (autoclaving, microwaving, and UV radiation) BPA-free PC-replacement products. An EA antagonist, ICI 182,780, was used to confirm that agonist activity in leachates was due to chemicals that activated the mammalian estrogen receptor. RESULTS: Many unstressed and stressed, PC-replacement-products made from acrylic, polystyrene, polyethersulfone, and Tritan™ resins leached chemicals with EA, including products made for use by babies. Exposure to various forms of UV radiation often increased the leaching of chemicals with EA. In contrast, some BPA-free PC-replacement products made from glycol-modified polyethylene terephthalate or cyclic olefin polymer or co-polymer resins did not release chemicals with detectable EA under any conditions tested. CONCLUSIONS: This hazard assessment survey showed that many BPA-free PC- replacement products still leached chemicals having significant levels of EA, as did BPA-containing PC counterparts they were meant to replace. That is, BPA-free did not mean EA-free. However, this study also showed that some PC-replacement products did not leach chemicals having significant levels of EA. That is, EA-free PC-replacement products could be made in commercial quantities at prices that compete with PC-replacement products that were not BPA-free. Since plastic products often have advantages (price, weight, shatter-resistance, etc.) compared to other materials such as steel or glass, it is not necessary to forgo those advantages to avoid release into foodstuffs or the environment of chemicals having EA that may have potential adverse effects on our health or the health of future generations.
Assuntos
Estrogênios/análise , Plásticos/química , Compostos Benzidrílicos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Estrogênios/química , Estrogênios/farmacologia , Etanol/química , Temperatura Alta , Humanos , Luciferases/metabolismo , Células MCF-7 , Micro-Ondas , Fenóis , Plásticos/efeitos da radiação , Receptores de Estrogênio/agonistas , Receptores de Estrogênio/metabolismo , Cloreto de Sódio/química , Raios UltravioletaRESUMO
BACKGROUND: Chemicals that have estrogenic activity (EA) can potentially cause adverse health effects in mammals including humans, sometimes at low doses in fetal through juvenile stages with effects detected in adults. Polycarbonate (PC) thermoplastic resins made from bisphenol A (BPA), a chemical that has EA, are now often avoided in products used by babies. Other BPA-free thermoplastic resins, some hypothesized or advertised to be EA-free, are replacing PC resins used to make reusable hard and clear thermoplastic products such as baby bottles. METHODS: We used two very sensitive and accurate in vitro assays (MCF-7 and BG1Luc human cell lines) to quantify the EA of chemicals leached into ethanol or water/saline extracts of fourteen unstressed or stressed (autoclaving, microwaving, UV radiation) thermoplastic resins. Estrogen receptor (ER)-dependent agonist responses were confirmed by their inhibition with the ER antagonist ICI 182,780. RESULTS: Our data showed that some (4/14) unstressed and stressed BPA-free thermoplastic resins leached chemicals having significant levels of EA, including one polystyrene (PS), and three Tritan™ resins, the latter reportedly EA-free. Exposure to UV radiation in natural sunlight resulted in an increased release of EA from Tritan™ resins. Triphenyl-phosphate (TPP), an additive used to manufacture some thermoplastic resins such as Tritan™, exhibited EA in both MCF-7 and BG1Luc assays. Ten unstressed or stressed glycol-modified polyethylene terephthalate (PETG), cyclic olefin polymer (COP) or copolymer (COC) thermoplastic resins did not release chemicals with detectable EA under any test condition. CONCLUSIONS: This hazard survey study assessed the release of chemicals exhibiting EA as detected by two sensitive, widely used and accepted, human cell line in vitro assays. Four PC replacement resins (Tritan™ and PS) released chemicals having EA. However, ten other PC-replacement resins did not leach chemicals having EA (EA-free-resins). These results indicate that PC-replacement plastic products could be made from EA-free resins (if appropriate EA-free additives are chosen) that maintain advantages of re-usable plastic items (price, weight, shatter resistance) without releasing chemicals having EA that potentially produce adverse health effects on current or future generations.
Assuntos
Proliferação de Células/efeitos dos fármacos , Estrogênios/toxicidade , Embalagem de Alimentos/normas , Expressão Gênica/efeitos dos fármacos , Plásticos/toxicidade , Polímeros/toxicidade , Bioensaio , Linhagem Celular , Humanos , Micro-Ondas , Pressão , Raios UltravioletaRESUMO
Background/purpose: Vertical root fracture (VRF) is a prevalent reason for tooth extraction following root canal treatment and even after crown placement. Predicting fractures is challenging due to multifactorial nature. The current study aimed to predict the likelihood of fracture following root canal treatment and crown placement by developing a deep learning (DL) model. Materials and methods: DL techniques were employed to analyze a dataset comprising 145 clinical cases consisting of 97 fractured teeth and 48 non-fractured teeth. This dataset spanned a five-year period and encompassed cases involving root canal therapy and crown installation. The analysis identified several root fracture-related parameters, which were incorporated into the DL system. The dataset consisted of 17 features presented in a mixed-type tabular format. Results: The deep neural network (DNN) model surpassed the support vector machine (SVM) model with a higher accuracy (80.7 % vs. 71.7 %) and F1-score value (0.857 vs. 0.817) for predicting root fracture. Furthermore, in determining root fracture occurrence, it was observed that 17 significant characteristics in the DNN model outperformed the 7 features by 11.7 % in accuracy and 10 % in F1-score. Conclusion: DL shows promise in predicting root fracture post root canal therapy and prosthesis, and it may have the potential to aid clinicians in assessing fracture risk and improving decision-making.
RESUMO
Nanocellulose-based biomaterials have gained significant attention in various fields, especially in medical and pharmaceutical areas, due to their unique properties, including non-toxicity, high specific surface area, biodegradability, biocompatibility, and abundant feasible and sophisticated strategies for functional modification. The biosafety of nanocellulose itself is a prerequisite to ensure the safe and effective application of biomaterials as they interact with living cells, tissues, and organs at the nanoscale. Potential residual endogenous impurities and exogenous contaminants could lead to the failure of the intended functionalities or even serious health complications if they are not adequately removed and assessed before use. This review summarizes the sources of impurities in nanocellulose that may pose potential hazards to their biosafety, including endogenous impurities that co-exist in the cellulosic raw materials themselves and exogenous contaminants caused by external exposure. Strategies to reduce or completely remove these impurities are outlined and classified as chemical, physical, biological, and combined methods. Additionally, key points that require careful consideration in the interpretation of the biosafety evaluation outcomes were discussed to ensure the safety and effectiveness of the nanocellulose-based biomaterials in medical applications.
Assuntos
Materiais Biocompatíveis , Contenção de Riscos BiológicosRESUMO
Nanocellulose (NC) is a promising biopolymer for various biomedical applications owing to its biocompatibility and low toxicity. However, it faces challenges in tissue engineering (TE) applications due to the inconsistency of the microenvironment within the NC-based scaffolds with target tissues, including anisotropy microstructure and biomechanics. To address this challenge, a facile swelling-induced nanofiber alignment and a novel in situ biomineralization reinforcement strategies were developed for the preparation of NC-based scaffolds with tunable anisotropic structure and mechanical strength for guiding the differentiation of bone marrow-derived mesenchymal stem cells for potential TE application. The bacterial cellulose (BC) and cellulose nanofibrils (CNFs) based scaffolds with tunable swelling anisotropic index in the range of 10-100 could be prepared by controlling the swelling medium. The in situ biomineralization efficiently reinforced the scaffolds with 2-4 times and 10-20 times modulus increasement for BC and CNFs, respectively. The scaffolds with higher mechanical strength were superior in supporting cell growth and proliferation, suggesting the potential application in TE application. This work demonstrated the feasibility of the proposed strategy in the preparation of scaffolds with mechanical anisotropy to induce cells-directed differentiation for TE applications.
Assuntos
Biomineralização , Diferenciação Celular , Celulose , Células-Tronco Mesenquimais , Nanofibras , Alicerces Teciduais , Celulose/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Alicerces Teciduais/química , Diferenciação Celular/efeitos dos fármacos , Anisotropia , Nanofibras/química , Engenharia Tecidual/métodos , Animais , Proliferação de Células/efeitos dos fármacos , Células da Medula Óssea/citologiaRESUMO
This is the first time when protein-imprinted polymers are prepared with "pending templates." The polymers were synthesized in the presence of a real sample (chicken egg white), rather than any known commercial proteins. Compared with a simultaneously synthesized nonimprinted control polymer, the polymers show higher adsorption capacity for abundant components (as "pending templates") in the original sample. Chromatography experiments indicated that the columns made of the imprinted polymers could retain abundant species (imprinted) and separate them from those not imprinted. Thus, the sample could be split into dimidiate subfractions with reduced complexities. "Pending template imprinting" suggests a new way to investigate molecular imprinting, especially to dissect, simplify, and analyze complicated samples through a series of polymers just imprinted by the samples per se.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Impressão Molecular/métodos , Polímeros/química , Proteínas/isolamento & purificação , Adsorção , Animais , Bovinos , Galinhas , Proteínas do Ovo/isolamento & purificação , Clara de Ovo/química , Hemoglobinas/isolamento & purificação , Muramidase/isolamento & purificação , Ovalbumina/isolamento & purificaçãoRESUMO
The adsorption method of Tenax-TA absorbent with GC-MS was used to analyze diurnal rhythms of volatiles from undamaged holly plants, Viburnum awabuki Kock (Dipsacales: Adoxaceae) holly infested by the white-striped longhorned beetle, Batocera lineolata Chevrolat (Coleoptera: Cerambycidae). Electroantennography and a Y-tube olfactometer were used to compare and analyze electroantennogram and behavioral responses of unmated male and female adults to the volatiles from V. awabuki (both undamaged and infested plants). The results of the GC-MS analysis showed that phytosterol and alkane are major volatiles for V. awabuki. The relative content of V. awabuki volatiles changed during the day. Electroantennogram and behavioral responses of unmated male and female adults to the volatiles from both undamaged and infested plants of V. awabuki were stronger between 08:00 and 10:00 and 16:00 and 18:00, which is consistent with early morning and evening feeding behaviors of adults in the field.