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1.
J Chem Phys ; 157(22): 224901, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36546812

RESUMO

The generalized Langevin equation (GLE) provides an attractive theoretical framework for investigating the dynamics of conformational fluctuations of polymeric systems. While the memory kernel is a central function in the GLE, explicit analytical forms for this function have been challenging to obtain, even for the simple models of polymer dynamics. Here, we achieve an explicit analytical expression for the memory kernel in the GLE for the end-to-end vector of Rouse chains in the overdamped limit. Our derivation takes advantage of the finding that the dynamics of the end-to-end vector of Rouse chains with both free ends are equivalent to those of Rouse chains with one free end and the other fixed. For the latter model, we first show that the equations of motion of the Rouse modes as well as their statistical properties can be obtained under the boundary conditions where the free end is held fixed temporarily. We then analytically solve the terms associated with intrachain interactions in the GLE. By formally comparing these terms with the GLE based on the Rouse modes, we obtain an explicit expression for the memory kernel, along with analytical forms for the potential field and the random colored noise force. Our analytical memory kernel is confirmed by numerical calculations in the Laplace space and is shown to yield asymptotic behaviors that are consistent with previous studies. Finally, we utilize our analytical result to simulate the cyclization dynamics of Rouse chains and discuss the scaling of the cyclization time with chain length.


Assuntos
Polímeros , Conformação Molecular , Movimento (Física)
2.
BMC Public Health ; 21(1): 2285, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34911491

RESUMO

BACKGROUND: This study aimed to explore the trend and risk indicators for dental caries of children aged 12 years in China based on national oral health survey data in 2005 and 2015. METHODS: Research data were from the two latest national oral health surveys conducted in mainland China, including 30 and 31 provinces, autonomous regions, and municipalities in 2005 and 2015, respectively. Children aged 12 years were clinically examined for dental caries and dental fluorosis according to the World Health Organization criteria. Sociodemographic characteristics and oral health-related behaviours were collected using questionnaires. Multilevel zero-inflated negative binomial regression model was used to investigate the association between dental caries severity and dental fluorosis, sociodemographic characteristics, and oral health-related behaviours. RESULTS: The final analyses included 12,350 and 27,818 children surveyed in 2005 and 2015, respectively. The standardized prevalence of dental caries increased from 27.05% (95% confidence interval [CI], 24.25-28.85) in 2005 to 37.92% (95% CI, 34.94-40.90) in 2015, and the respective standardized mean decayed, missing, filled teeth (DMFT) index scores increased from 0.50 (standard deviation [SD], 1.04) to 0.83 (SD, 1.45) (P < 0.001). Fujian province had the highest increase in dental caries, followed by Liaoning, Heilongjiang, Hainan, and Yunnan. Results revealed that children who were girls, more frequently experienced dental pain, and had more recent dental visits, had significantly higher DMFT scores after adjusting for the survey year and other variables (all P < 0.05). CONCLUSIONS: Dental caries of 12-year-old children in China deteriorated from 2005 to 2015, particularly in the northeast and southwest regions. Dental caries was associated with sex, dental pain, and dental service utilization.


Assuntos
Cárie Dentária , Criança , China/epidemiologia , Estudos Transversais , Índice CPO , Cárie Dentária/epidemiologia , Feminino , Humanos , Análise Multinível , Prevalência
3.
BMC Oral Health ; 21(1): 229, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941169

RESUMO

BACKGROUND: The relationship between dental caries and periodontal disease is still controversial. The objective of this study was to explore the relationship between different types of caries and periodontal disease severity in middle-aged and elderly people in China. METHODS: The study population consisted of 4407 middle-aged and 4117 elderly subjects. Caries were divided into the following three types: type A, crown caries; type B, lesions involving both the crown and root, representing mixed-type caries; and type C, root caries. These three types together represent the overall caries situation, which we call type ABC. Caries were quantitated by decayed and filled teeth (DFT index). Periodontitis was evaluated by clinical attachment loss. RESULTS: Middle-aged people with periodontitis had a significant association with DFT type B (OR: 1.21, 95% CI 1.17-1.25) and type C (OR: 1.40, 95% CI 1.24-1.56). Elderly people with periodontitis had a significant association with DFT type C (OR: 1.28, 95% CI 1.21-1.35). CONCLUSIONS: In China, caries types B/C were positively correlated with periodontitis in the middle-aged group, and only caries type C was positively correlated with periodontitis in the elderly group.


Assuntos
Cárie Dentária , Doenças Periodontais , Idoso , China/epidemiologia , Índice CPO , Cárie Dentária/epidemiologia , Suscetibilidade à Cárie Dentária , Inquéritos de Saúde Bucal , Humanos , Pessoa de Meia-Idade , Saúde Bucal , Doenças Periodontais/complicações , Doenças Periodontais/epidemiologia
4.
J Virol ; 93(13)2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30996087

RESUMO

Enterovirus A71 (EV-A71) is a major pathogen that causes hand-foot-and-mouth disease (HFMD), which occasionally results in severe neurological complications. In this study, we developed four EV-A71 (rgEV-A71) strains by reverse genetics procedures as possible vaccine candidates. The four rgEV-A71 viruses contained various codon-deoptimized VP1 capsid proteins (VP1-CD) and showed replication rates and antigenicity similar to that of the wild-type virus, while a fifth virus, rg4643C4VP-CD, was unable to form plaques but was still able to be examined by median tissue culture infectious dose (TCID50) titers, which were similar to those of the others, indicating the effect of CD on plaque formation. However, the genome stability showed that there were some mutations which appeared during just one passage of the VP1-CD viruses. Thus, we further constructed VP1-CD rgEV-A71 containing high-fidelity determinants in 3D polymerase (CD-HF), and the number of mutations in CD-HF rgEV-A71 was shown to have decreased. The CD-HF viruses showed less virulence than the parental strain in a mouse infection model. After 14 days postimmunization, antibody titers had increased in mice infected with CD-HF viruses. The mouse antisera showed similar neutralizing antibody titers against various CD-HF viruses and different genotypes of EV-A71. The study demonstrates the proof of concept that VP1 codon deoptimization combined with high-fidelity 3D polymerase decreased EV-A71 mutations and virulence in mice but retained their antigenicity, indicating it is a good candidate for next-generation EV-A71 vaccine development.IMPORTANCE EV-A71 can cause severe neurological diseases with fatality in infants and young children, but there are still no effective drugs to date. Here, we developed a novel vaccine strategy with the combination of CD and HF substitutions to generate the genetically stable reverse genetics virus. We found that CD combined with HF polymerase decreased the virulence but maintained the antigenicity of the virus. This work demonstrated the simultaneous introduction of CD genome sequences and HF substitutions as a potential new strategy to develop attenuated vaccine seed virus. Our work provides insight into the development of a low-virulence candidate vaccine virus through a series of genetic editing of virus sequences while maintaining its antigenicity and genome stability, which will provide an additional strategy for next-generation vaccine development of EV-A71.


Assuntos
Proteínas do Capsídeo/imunologia , Códon , Infecções por Enterovirus/imunologia , Infecções por Enterovirus/prevenção & controle , Enterovirus/imunologia , Imunogenicidade da Vacina/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes , Antígenos Virais/genética , Antígenos Virais/imunologia , Sequência de Bases , Proteínas do Capsídeo/genética , Enterovirus/genética , Enterovirus/crescimento & desenvolvimento , Enterovirus Humano A/genética , Enterovirus Humano A/imunologia , Infecções por Enterovirus/virologia , Instabilidade Genômica , Doença de Mão, Pé e Boca/imunologia , Doença de Mão, Pé e Boca/prevenção & controle , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mutação , Virulência , Replicação Viral
5.
BMC Musculoskelet Disord ; 21(1): 331, 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32466749

RESUMO

BACKGROUND: Allografts and polyetheretherketone (PEEK) cages are the two most commonly used materials in anterior cervical discectomy and fusion (ACDF). However, their effectiveness in two-level ACDF remains controversial. The primary aim of this retrospective study was to compare the clinical and radiological outcomes of two-level ACDF with plate fixation using either a structural allograft or a PEEK cage. METHODS: From 2010 to 2015, 88 consecutive patients underwent two-level ACDF, of whom 53 received an allograft and 35 patients received a PEEK cage. All PEEK cages were filled with local autografts. All clinical outcomes were prospectively collected before and six months and two years after surgery. Clinical efficacy was evaluated using a visual analogue scale for neck pain and limb pain, the Neck Pain and Disability Score, the Neck Disability Index, the Neurogenic Symptom Score, and the Japanese Orthopedic Association score. Radiological outcomes were assessed preoperatively, immediately after surgery, and at the final follow-up. RESULTS: A preoperative comparison revealed no difference between the two patient groups in terms of age, sex, body mass index, smoking status, preoperative symptoms, operation level, or follow-up (mean = 42.8 months). No differences in the improvements in clinical outcomes were observed between the two groups. Both groups showed significant improvement in mean disc height, segmental height, and segmental lordosis postoperatively. The fusion rate for the PEEK cage was 100% at both levels, while the fusion rate for the allograft group was 98.1% at the cephalad level and 94.2% at the caudad level (p > 0.05). Subsidence at the cephalad level occurred in 22.9% (8/35) of segments in the PEEK group and 7.7% (4/52) of segments in the allograft group (p = 0.057). At the caudal level, a higher incidence of cage subsidence was noted in the PEEK group than in the allograft group [37.1% (13/35) versus 15.4% (8/52)] (p = 0.02). Overall, subsidence was noted in 30% (21/70) of the PEEK group and in 11% (12/104) of the allograft group (p <  0.05). CONCLUSION: The use of PEEK cages resulted in a higher rate of subsidence in two-level ACDF than the use of allografts. Two-level ACDF using either allografts or PEEK cages resulted in similar clinical outcomes, radiological improvements in alignment and fusion rates.


Assuntos
Aloenxertos/normas , Vértebras Cervicais/cirurgia , Discotomia/instrumentação , Cetonas/administração & dosagem , Polietilenoglicóis/administração & dosagem , Fusão Vertebral/instrumentação , Benzofenonas , Placas Ósseas , Vértebras Cervicais/diagnóstico por imagem , Avaliação da Deficiência , Discotomia/tendências , Feminino , Seguimentos , Humanos , Cetonas/normas , Lordose/diagnóstico por imagem , Lordose/etiologia , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis/normas , Polímeros , Radiografia , Estudos Retrospectivos , Fusão Vertebral/tendências , Transplante Homólogo , Resultado do Tratamento
6.
BMC Oral Health ; 20(1): 137, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393260

RESUMO

BACKGROUND: The financial burden of oral diseases is a growing concern as the medical expenses rise worldwide. The aim of this study was to investigate the dental expenditure, analyze its progressivity and horizontal inequality under the general health finance and insurance system, and identify the key social determinants of the inequality for Chinese adults. METHODS: A secondary analysis used the data of 13,464 adults from the 4th National Oral Health Epidemiological Survey (NOHES) in China was undertaken. The dental expenditure was collected and divided into out-of-pocket and health insurance payments. Horizontal inequality index and Kakwani index were used to analyze the horizontal inequality and progressivity, respectively. The decomposition model of the concentration index was set up to explore the associated socioeconomic determinants. RESULTS: The results showed that a mean dental expenditure per capita of Chinese adults was $20.55 (95% Confidence Interval-CI: 18.83,22.26). Among those who actually used dental service, the cost was $100.95 (95%CI: 93.22,108.68). Over 90% of dental spending was due to out-of-pocket expenses. For self-reported oral health, the horizontal inequality index was - 0.1391 and for the decayed tooth (DT), it was - 0.2252. For out-of-pocket payment, the Kakwani index was - 0.3154 and for health insurance payment it was - 0.1598. Income, residential location, educational attainment, oral hygiene practice, self-reported oral health, age difference were the main contributors to the inequality of dental expenditure. CONCLUSION: Dental expenditure for Chinese adults was at a lower level due to underutilization. The ratio of payments of dental expenditure and utilization was disproportional, whether it was out-of-pocket or insurance payment. Individuals who were more in need of oral care showed less demand for service or not required service in time. For future policy making on oral health, it is worth the effort to further promote the awareness of the importance of oral health and utilization of dental service.


Assuntos
Gastos em Saúde , Saúde Bucal/economia , Fatores Socioeconômicos , Adulto , China/epidemiologia , Feminino , Humanos , Masculino , Inquéritos e Questionários
7.
Pharm Res ; 36(1): 20, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30511187

RESUMO

PURPOSE: The pH-responsive copolymer micelles are widely used as carriers in drug delivery system, but there are few micro-level mechanistically explorations on the pH-triggered drug release. Here we elucidate the relationship between drug release behavior of four/six-arms star copolymer micelles and the copolymer structures. METHOD: The net cumulative drug release percentage (En) was taken as the dependent variables, block unit autocorrelation descriptors as independent variables. The quantitative structure-property relationship models of drug release from block copolymers were developed at pH 7.4 and 5.0 of two periods (stage I: 0~12 h, stage II: 12~96 h). RESULTS: The models built are of good fitting ability, internal predictive ability, stability and statistically significance. Drug diffusion is mainly influenced by the intra-block force, and micellar erosion by inter-block force. At pH 5.0, lowest unoccupied molecular orbital energy of copolymer unit is the main factor influencing the En. Stage I of drug release is affected by hydrophobic property and stage II by regional polar of copolymer molecules. CONCLUSION: The models present good performance, factors affecting drug release behavior at different pH conditions can offer guidance for the design of copolymer structures to control the drug release behavior of micelles in a targeted and quantitatively way.


Assuntos
Micelas , Polímeros/química , Portadores de Fármacos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Relação Quantitativa Estrutura-Atividade
8.
Int J Mol Sci ; 18(5)2017 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-28441355

RESUMO

Despite standard treatment, about 70% of ovarian cancer will recur. Cancer stem cells (CSCs) have been implicated in the drug-resistance mechanism. Several drug resistance mechanisms have been proposed, and among these, autophagy plays a crucial role for the maintenance and tumorigenicity of CSCs. Compared to their differentiated counterparts, CSCs have been demonstrated to display a significantly higher level of autophagy flux. Moreover, mitophagy, a specific type of autophagy that selectively degrades excessive or damaged mitochondria, is shown to contribute to cancer progression and recurrence in several types of tumors. Nanomedicine has been shown to tackle the CSCs problem by overcoming drug resistance. In this work, we developed a nanomedicine, 188Re-liposome, which was demonstrated to target autophagy and mitophagy in the tumor microenvironment. Of note, the inhibition of autophagy and mitophagy could lead to significant tumor inhibition in two xenograft animal models. Lastly, we presented two cases of recurrent ovarian cancer, both in drug resistance status that received a level I dose from a phase I clinical trial. Both cases developing drug resistance showed drug sensitivity to 188Re-liposome. These results suggest that inhibition of autophagy and mitophagy by a nanomedicine may be a novel strategy to overcome drug resistance in ovarian cancer.


Assuntos
Autofagia/efeitos dos fármacos , Lipossomos/química , Mitocôndrias/efeitos dos fármacos , Compostos Radiofarmacêuticos/toxicidade , Animais , Antígeno Ca-125/sangue , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Nanomedicina , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/radioterapia , Radioisótopos/química , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/uso terapêutico , Rênio/química , Transplante Heterólogo
9.
Eur J Orthod ; 37(3): 290-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25246607

RESUMO

OBJECTIVE: To investigate effects of mandibular advancement device (MAD) therapy for obstructive sleep apnoea hypopnea syndrome (OSAHS) on the genioglossus contractile properties and fibre-type distribution. MATERIALS AND METHODS: Thirty 6-month old male New Zealand white rabbits were randomised into three groups: OSAHS, MAD, and controls. Rabbits in Group OSAHS and Group MAD were established as OSAHS models by injection, at a dose of 2 ml hydrophilic polyacrylamide gel, via the submucous muscular layer of soft palate. Spiral computed tomography (CT) showed a significant reduced retropalatal upper airway, and apnoeas happened with an increase of Apnea Hypopnea Index (AHI) and a decrease of blood oxygen saturation during polysomnography (PSG), which indicated the OSAHS model developed successfully. OSAHS rabbits in Group MAD were fitted with a MAD made from self-curing composite resin, at 30 degrees to the upper incisors, and the mandible was guided forward 3 to 4mm. Further, spiral CT and PSG suggested MAD was effective. Rabbits in 3 groups were induced to sleep for 4-6 hours per day for 8 weeks, after which the genioglossus was removed, mounted in a tissue bath, and stimulated through platinum electrodes; maximal twitch tension, contraction time, half-relaxation time, force-frequency relationship, and fatigability were recorded. The percentage of Type I and Type II fibres was quantified. RESULTS: The fatigability and percentage of Type II fibres of genioglossus increased in Group OSAHS compared with controls; this abnormality was corrected by MAD. CONCLUSION: MAD therapy for OSAHS could prevent genioglossus fatigue and abnormal fibre-type distribution of genioglossus in OSAHS.


Assuntos
Avanço Mandibular/instrumentação , Aparelhos Ortodônticos , Apneia Obstrutiva do Sono/terapia , Língua/patologia , Resinas Acrílicas/administração & dosagem , Adenosina Trifosfatases/análise , Animais , Modelos Animais de Doenças , Estimulação Elétrica , Injeções , Masculino , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Fibras Musculares de Contração Rápida/patologia , Fibras Musculares de Contração Rápida/fisiologia , Tono Muscular/fisiologia , Oxigênio/sangue , Palato Mole/efeitos dos fármacos , Palato Mole/patologia , Polissonografia/métodos , Coelhos , Distribuição Aleatória , Tomografia Computadorizada Espiral/métodos , Língua/fisiopatologia
10.
Int J Biol Macromol ; 271(Pt 1): 132595, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38821803

RESUMO

Biomass chitosan has garnered considerable interest for alkaline anion exchange membranes (AEMs) due to its eco-friendly and sustainable characteristics, low reactant permeability and easily modifiable nature, but it still faces the trade-off between high hydroxide conductivity and sufficient mechanical properties. Herein, a novel functionalized attapulgite clay (f-ATP) with a unique ionic "chain-ball" surface structure was prepared and incorporated with quaternized chitosan (QCS)/polyvinyl alcohol (PVA) matrix to fabricate high-performance composite AEMs. Due to the strengthened interfacial bonding between f-ATP nanofillers and the QCS/PVA matrix, composite membranes are synergistically reinforced and toughened, achieving peak tensile strength and elongation at break of 24.62 MPa and 33.8 %. Meanwhile, abundant ion pairs on f-ATP surface facilitate ion transport in the composite AEMs, with the maximum OH- conductivity of 46 mS cm-1 at 80 °C and the highest residual IEC of 83 % after alkaline treatment for 120 h. Moreover, the assembled alkaline direct methanol fuel cell exhibits a remarkable power density of 49.3 mW cm-2 at 80 °C. This work provides a new strategy for fabricating high-performance anion exchange membranes.


Assuntos
Quitosana , Argila , Compostos de Magnésio , Membranas Artificiais , Álcool de Polivinil , Compostos de Silício , Quitosana/química , Álcool de Polivinil/química , Compostos de Magnésio/química , Compostos de Silício/química , Argila/química , Ânions/química , Troca Iônica , Resistência à Tração , Propriedades de Superfície
11.
Shanghai Kou Qiang Yi Xue ; 33(2): 180-185, 2024 Apr.
Artigo em Zh | MEDLINE | ID: mdl-39005096

RESUMO

PURPOSE: To investigate the efficacy of a modified maxillary protraction appliance in patients of skeletal Class Ⅲ with crowding. METHODS: Forty patients with skeletal Class Ⅲ malocclusion were divided into two groups, with 20 patients in each group. The experimental group had molar in a neutral or distal relationship and applied a modified maxillary protraction appliance, while the control group had molar mesial relationship and applied a conventional maxillary protraction appliance. Lateral cephalometric radiographs were taken before and after treatment in both groups for comparison. SPSS 22.0 software package was used for data analysis. RESULTS: The angle measurements taken before and after treatment showed a significant increase in SNA, ANB, SN-MP and U4-SN(P<0.01), while SNB decreased(P<0.01) in both groups. SN-OL changes were statistically different before and after treatment in the experimental group(P<0.05). The sagittal measurements before and after treatment in both groups showed significant alterations in all(P<0.05) but the length of the maxillary arch in both groups. For vertical measurements, U1-PP, L1-MP, U4-SN, U6-SN, and ANS-ME all increased (P<0.05), while the changes of U4-PP and U6-PP in the two groups before and after treatment were statistically different(P<0.05). Compared with the control group, the experimental group had a significantly increased maxillary arch length, a more remote location at U6, and a less variable molar relationship after treatment(P<0.01). The two groups showed a variable amount of cephalometric measurements before and after treatment: the experimental group had a significant increase in maxillary arch length, a more remote position at U6, and a smaller change in molar relationship compared to the control group(P<0.01). CONCLUSIONS: The modified maxillary protraction appliance showed good results for maxillary protraction and pushing the molar distally in patients with skeletal Class Ⅲ with crowding at neutral or distal molar relationship.


Assuntos
Cefalometria , Má Oclusão Classe III de Angle , Maxila , Humanos , Má Oclusão Classe III de Angle/terapia , Má Oclusão/terapia
12.
J Mech Behav Biomed Mater ; 151: 106361, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38176199

RESUMO

The use of all porcelain materials in dentistry has significantly increased in recent years. However, chipping has remained a common problem that affects bilayered zirconia restorations. Bonding between porcelain and the underlying zirconia framework is crucial to the success of the restoration. The bond strength may be affected by such factors as residual thermal stress and the veneering technique. This research focuses on investigating the potential and constraints of materials through an examination of the porcelain veneering technique, particularly hand-layering and heat-pressing. Forty-two cylindrical disc samples of zirconia (n = 7/group) were fabricated in the dimensions of 10 × 1.2 mm (diameter [D] × height [H]). The zirconia specimens were milled from IPS e.max® ZirCad [Z] block and Luxen Zr [L] block (n = 21/zirconia). The zirconia cores were layered with IPS e.max® Zirliner and heat-pressed with IPS e.max® ZirPress to produce a final veneer dimension of 5 × 3 mm (D × H). Conventional layering was performed for the rest of the zirconia cores using IPS e.max® Ceram and Shofu Vintage Zr. The final study groups were Luxen-Vintage (LV), Luxen-Ceram (LC), Luxen Zirpress (LP), ZirCad-Vintage (ZV), ZirCad-Ceram (ZC) and ZirCad-Zirpress (ZP). Five samples were subjected to shear bond testing (SBS) with a universal testing machine with a 5 kN load cell and 0.5 mm/min crosshead speed (n = 5/group). A sample underwent nanoindentation, and another was sectioned using Isomet machine to study the bonding interface. One-way ANOVA was used to run the statistical analyses of the SBS test. Statistical differences were found between ZV with LC and LP (p < 0.05). Residual stress is estimated to be higher in the middle of the porcelain compared with that on the surface and the interface. FESEM imaging reveals portions of visible bare zirconia on Luxen zirconia, whilst crack propagation occurred through voids in all hand-layered groups. Heat-pressed veneering showed comparable but not superior results to conventional hand-layered veneering. Heat-pressed veneering produced similar stress distribution profiles compared with hand-layered veneering.


Assuntos
Porcelana Dentária , Zircônio , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio/química , Materiais Dentários , Análise do Estresse Dentário , Facetas Dentárias , Cerâmica/química
13.
Biomed Tech (Berl) ; 67(1): 53-60, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35073618

RESUMO

The macro and micro design is essential to the biomechanical performance of a short implant. In this study, the implant thread parameters of short implants used in edentulous maxillae will be discussed. The aim of the study is to analyse biomechanical distinctions in different thread parameters over short implants by applying the vertical or oblique load of 130 N on dental prosthesis. A 6*5 mm implant will be used in posterior maxillae arch, where the molar region locates. The CAD model has been assembled by three parts, a crown, an implant system and a jaw. By applying the vertical or oblique load to the crown, the Von-Mises stresses of cortical bone and trabecular bone will be evaluated in pairs along the lines v1-v2 & a1-a2. The results showed that the reverse buttress thread would induce more stresses in cancellous bone whereas the buttress did the opposite. The trapezoidal thread (V-thread) is more favourable than the reverse buttress thread in accordance to the FEA result. The rectangle threads will induce more uneven stresses in cancellous bones.


Assuntos
Implantes Dentários , Software , Fenômenos Biomecânicos , Simulação por Computador , Planejamento de Prótese Dentária , Análise do Estresse Dentário , Análise de Elementos Finitos , Estresse Mecânico
14.
Carbohydr Res ; 522: 108675, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36182822

RESUMO

We propose a new approach for the synergistically catalytic conversion of cellulose to levulinic acid (LA) in water by SO3H-functionalized ionic liquid (SFIL) and lanthanide chloride (LnCl3). Compared with using 1-methyl-3-(3-sulfopropyl)imidazolium chloride ([MIMPS]Cl) only, the LA yield using [MIMPS]Cl and ErCl3 increased by 14.4% and 13.6% at 50 mol% of IL and 30 mol% of IL, respectively. Moreover, the combined [MIMPS]Cl and ErCl3 system can tolerate high concentrations of substrates and maintain high activity at eleven runs. We also investigated the effects of the cation structure of ionic liquids (alkyl chain length, hydroxyl groups on the side chains, and aromatic properties) on LA production. The observations can provide useful information for designing efficient ionic liquid catalysts for biomass utilization.


Assuntos
Líquidos Iônicos , Líquidos Iônicos/química , Celulose/química , Cloretos , Água/química , Catálise
15.
Community Dent Oral Epidemiol ; 50(4): 311-320, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-34213027

RESUMO

OBJECTIVE: The purpose of this study was to assess the associations between the self-reported oral health-related quality of life (OHRQoL) of older Chinese people and their socio-economic status and oral health using data collected in the 4th National Oral Health Survey. METHODS: After multistage stratified cluster sampling, 4332 adults aged 65-74 years participated in the study. After a clinical examination, the participants completed a structured questionnaire. A Mandarin version of the General Oral Health Assessment Index (GOHAI) was included in the questionnaire. Clinical examinations were carried out using the criteria recommended by the World Health Organization. Multivariate analysis was used to evaluate the associations of the clinical and socio-demographic variables with the GOHAI scores of the participants. RESULTS: The weighted mean (SE) GOHAI score was 51.6 (0.0). Female sex and having more than 10 missing teeth, unrestored tooth spaces, more than 10 decayed teeth and a periodontal pocket ≥6 mm were negatively associated with the GOHAI score, while having a higher education level and living in the Eastern region of China were positively associated with the GOHAI score. CONCLUSION: After adjustment for confounders, the OHRQoL of older Chinese individuals was mainly affected by untreated dental caries and the loss of teeth. Older Chinese individuals who were male, had a higher education level, were from the Eastern region, had no unrestored tooth spaces or deep periodontal pockets and had fewer decayed or missing teeth had higher GOHAI scores, indicating better OHRQoL.


Assuntos
Cárie Dentária , Perda de Dente , Adulto , Idoso , China/epidemiologia , Feminino , Humanos , Masculino , Saúde Bucal , Bolsa Periodontal , Qualidade de Vida , Inquéritos e Questionários
16.
Beijing Da Xue Xue Bao Yi Xue Ban ; 43(1): 112-6, 2011 Feb 18.
Artigo em Zh | MEDLINE | ID: mdl-21321633

RESUMO

OBJECTIVE: To evaluate the effectiveness of desensitizing toothpaste containing 5.53% potassium citrate on dentine hypersensitivity. METHODS: This was a randomized, double-blinded, controlled, clinical trial. Those, who satisfied the inclusion criteria, were recruited into the study and randomized allocated into test group and control group according to gender and age group. At baseline, 67 subjects (36 in test group, 31 in control group) were recruited into the study. The dentine hypersensitivity was evaluated by a subject self-perceived short, sharp pain in visual analogue scale (VAS) in response to a blast of cold air from a triple syringe administered to a tooth surface in 1 cm. Test toothpastes, containing 5.53% potassium citrate and 0.76% sodium monofluorophosphate, and control toothpastes, containing only 0.76% sodium monofluorophosphate were delivered to the study subjects in the test and control group respectively. The subjects were asked to brush their teeth twice a day, and at least one minute each time. During the 8-week study period, a subjective evaluation of changes in the individuals overall sensitivity to everyday stimuli was also scored in VAS. RESULTS: At the end of the trial data of 57 subjects (31 in test group, 26 in control group) was used for analysis. From baseline to 8-week evaluation, the mean VAS values to cold air and subjects' self-perceived VAS values of the subjects decreased both in the test and control groups. Furthermore, the reduction in mean VAS values to cold air from baseline to 4-week of the test subjects was statistically significant higher than that of the control (1.12 vs. 0.32, P<0.05). The reduction in mean subjects' self-perceived VAS values from baseline to 8-week of the test subjects was statistically significant higher than that of the control (1.59 vs. 0.24, P<0.05). CONCLUSION: RESULTS of the clinical trial showed that toothpastes containing 5.53% potassium citrate were effective in reducing dentine hypersensitivity.


Assuntos
Sensibilidade da Dentina/tratamento farmacológico , Citrato de Potássio/administração & dosagem , Cremes Dentais/química , Adolescente , Adulto , Método Duplo-Cego , Feminino , Fluoretos/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Fosfatos/administração & dosagem , Adulto Jovem
17.
Clin Nucl Med ; 46(1): e11-e12, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33156043

RESUMO

McCune-Albright syndrome is a rare condition consisting of triad of fibrous dysplasia, hyperfunctioning endocrinopathy, and café au lait macules of skin. A 31-year-old man was diagnosed with fibrous dysplasia 18 years before presenting with pathologic fracture. No workup for polyostotic fibrous dysplasia was performed at that time. He now presented with left facial swelling and skeletal features of acromegaly. MRI revealed a 15-cm enhancing tumor diagnosed histopathologically as high-grade osteosarcoma. Tc-methylene diphosphonate bone scintigraphy revealed decreased uptake at the tumor site contrary to the usual finding of avid uptake by the neoplastic bone forming tumor.


Assuntos
Neoplasias Ósseas/complicações , Neoplasias Ósseas/diagnóstico por imagem , Displasia Fibrosa Poliostótica/complicações , Mandíbula/diagnóstico por imagem , Osteossarcoma/complicações , Osteossarcoma/diagnóstico por imagem , Acromegalia/complicações , Adulto , Humanos , Imageamento por Ressonância Magnética , Masculino
18.
Chin J Dent Res ; 24(2): 105-112, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34219443

RESUMO

adolescents aged 12 to 15 years based on the 4th National Oral Health Survey and to explore its associated factors. METHODS: Students aged 12 to 15 years were recruited using to a multistage stratified random sampling method. All the subjects received oral examination and completed a questionnaire. Information relating to OHRQoL was collected through a Mandarin version of the child oral impacts on daily performances (Child-OIDP) questionnaire. The relationship between the Child-OIDP scores and independent variables was assessed using a Mann-Whitney U-test, Kruskal-Wallis test and a multivariate Poisson regression. RESULTS: A total of 89,582 subjects were included in the analysis, of whom 76.6% reported oral impacts in the last 6 months. Eating was the most affected daily performance. The results of the regression analysis showed that factors associated with adolescents' OHRQoL included sex, location of residence, region, only child status, parents' level of education, frequency of sugar consumption, self-perception of general/oral health, dental appointments in the past 12 months, oral health knowledge status, age, decayed, missing and filled teeth (DMFT) index and number of teeth with gingival bleeding. CONCLUSION: Oral impacts were common among Chinese adolescents, although most were not so severe. Eating was the most commonly affected performance. Sex, location of residence, region, only child status, parents' level of education, frequency of sugar consumption, selfperception of general/oral health status, dental appointments in the previous 12 months, oral health knowledge status, age, DMFT index and number of teeth with gingival bleeding were found to be associated with OHRQoL.


Assuntos
Cárie Dentária , Qualidade de Vida , Adolescente , China , Estudos Transversais , Inquéritos de Saúde Bucal , Humanos , Saúde Bucal , Inquéritos e Questionários
19.
Clin Nucl Med ; 45(2): e92-e93, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31876809

RESUMO

A 61-year-old woman with multiple hepatic metastases from uterus cervical cancer received Y radioembolization. The simultaneous time-of-flight (TOF) PET/MR clearly identified the untreated tumor parts on the posttherapeutic Y internal pair-production imaging. After another boosted Y injection, the metastatic hepatic tumors were well covered. The follow-up PET/MR revealed tumor shrinkage. The one-stop-shop TOF PET/MR provided useful follow-up information in patients receiving Y radioembolization.


Assuntos
Embolização Terapêutica , Neoplasias Hepáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Neoplasias do Colo do Útero/patologia , Radioisótopos de Ítrio/metabolismo , Radioisótopos de Ítrio/uso terapêutico , Feminino , Humanos , Cinética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Microesferas , Pessoa de Meia-Idade , Imagem Multimodal , Resinas Sintéticas/química , Radioisótopos de Ítrio/química
20.
Oral Health Prev Dent ; 7(3): 261-7, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19780433

RESUMO

PURPOSE: The aim of the present study was to evaluate the effect of providing outreach oral health care services on the oral health status and oral health-related quality of life to institutionalised elders in Hong Kong. MATERIALS AND METHODS: At baseline, 232 Chinese adults aged 65 to 80 years living in 14 elderly homes participated in a free oral health examination and completed a validated Chinese version of general oral health assessment index (GOHAI) in a face-to-face interview. Afterwards, free dental treatments, including extractions, scaling and fillings, were offered to the subjects every year according to their needs. On the third year, the subjects were examined and interviewed again at least 6 months after the last treatment. RESULTS: A total of 144 elders (62.1%) were examined and interviewed at the time of evaluation. Their oral health status had improved greatly compared with that found at baseline. They had fewer decayed teeth (1.3 versus 2.0, P < 0.001), and a lower proportion of the dentate subjects had periodontal pockets (60.9% versus 28.9%, P < 0.001). However, no significant change in their mean GOHAI score between baseline and the time of evaluation was detected. Despite this, a higher proportion of the elders were satisfied with their own oral health at the time of evaluation compared with baseline (66.2% versus 75.7%, P = 0.047). CONCLUSIONS: The provision of outreach oral health care services can lead to an improvement in both the assessed and the perceived oral health status of institutionalised elders.


Assuntos
Atenção à Saúde/métodos , Assistência Odontológica para Idosos/métodos , Nível de Saúde , Saúde Bucal , Qualidade de Vida/psicologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Relações Comunidade-Instituição , Assistência Odontológica para Idosos/psicologia , Inquéritos de Saúde Bucal , Feminino , Instituição de Longa Permanência para Idosos , Humanos , Institucionalização , Estudos Longitudinais , Masculino , Resultado do Tratamento
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