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1.
Mem Cognit ; 51(5): 1249-1263, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36581728

RESUMO

Previous research has demonstrated that the ease or difficulty of processing complex semantic expressions depends on sentence structure: Processing difficulty emerges when the constituents that create the complex meaning appear in the same clause, whereas difficulty is reduced when the constituents appear in separate clauses. The goal of the current eye-tracking-while-reading experiments was to determine how changes to sentence structure affect the processing of lexical repetition, as this manipulation enabled us to isolate processes involved in word recognition (repetition priming) from those involved in sentence interpretation (felicity of the repetition). When repetition of the target word was felicitous (Experiment 1), we observed robust effects of repetition priming with some evidence that these effects were weaker when repetition occurred within a clause versus across a clause boundary. In contrast, when repetition of the target word was infelicitous (Experiment 2), readers experienced an immediate repetition cost when repetition occurred within a clause, but this cost was eliminated entirely when repetition occurred across clause boundaries. The results have implications for word recognition during reading, processes of semantic integration, and the role of sentence structure in guiding these linguistic representations.


Assuntos
Idioma , Leitura , Humanos , Semântica , Priming de Repetição
2.
Sensors (Basel) ; 23(5)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36904607

RESUMO

Condition-Based Maintenance (CBM), based on sensors, can only be reliable if the data used to extract information are also reliable. Industrial metrology plays a major role in ensuring the quality of the data collected by the sensors. To guarantee that the values collected by the sensors are reliable, it is necessary to have metrological traceability made by successive calibrations from higher standards to the sensors used in the factories. To ensure the reliability of the data, a calibration strategy must be put in place. Usually, sensors are only calibrated on a periodic basis; so, they often go for calibration without it being necessary or collect data inaccurately. In addition, the sensors are checked often, increasing the need for manpower, and sensor errors are frequently overlooked when the redundant sensor has a drift in the same direction. It is necessary to acquire a calibration strategy based on the sensor condition. Through online monitoring of sensor calibration status (OLM), it is possible to perform calibrations only when it is really necessary. To reach this end, this paper aims to provide a strategy to classify the health status of the production equipment and of the reading equipment that uses the same dataset. A measurement signal from four sensors was simulated, for which Artificial Intelligence and Machine Learning with unsupervised algorithms were used. This paper demonstrates how, through the same dataset, it is possible to obtain distinct information. Because of this, we have a very important feature creation process, followed by Principal Component Analysis (PCA), K-means clustering, and classification based on Hidden Markov Models (HMM). Through three hidden states of the HMM, which represent the health states of the production equipment, we will first detect, through correlations, the features of its status. After that, an HMM filter is used to eliminate those errors from the original signal. Next, an equal methodology is conducted for each sensor individually and using statistical features in the time domain where we can obtain, through HMM, the failures of each sensor.

3.
Sensors (Basel) ; 23(18)2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37766042

RESUMO

Induction motors (IMs) are widely used in industrial applications due to their advantages over other motor types. However, the efficiency and lifespan of IMs can be significantly impacted by operating conditions, especially Unbalanced Supply Voltages (USV), which are common in industrial plants. Detecting and accurately assessing the severity of USV in real-time is crucial to prevent major breakdowns and enhance reliability and safety in industrial facilities. This paper presented a reliable method for precise online detection of USV by monitoring a relevant indicator, denominated by negative voltage factor (NVF), which, in turn, is obtained using the voltage symmetrical components. On the other hand, impedance estimation proves to be fundamental to understand the behavior of motors and identify possible problems. IM impedance affects its performance, namely torque, power factor and efficiency. Furthermore, as the presence of faults or abnormalities is manifested by the modification of the IM impedance, its estimation is particularly useful in this context. This paper proposed two machine learning (ML) models, the first one estimated the IM stator phase impedance, and the second one detected USV conditions. Therefore, the first ML model was capable of estimating the IM phases impedances using just the phase currents with no need for extra sensors, as the currents were used to control the IM. The second ML model required both phase currents and voltages to estimate NVF. The proposed approach used a combination of a Regressor Decision Tree (DTR) model with the Short Time Least Squares Prony (STLSP) technique. The STLSP algorithm was used to create the datasets that will be used in the training and testing phase of the DTR model, being crucial in the creation of both features and targets. After the training phase, the STLSP technique was again used on completely new data to obtain the DTR model inputs, from which the ML models can estimate desired physical quantities (phases impedance or NVF).

4.
Sensors (Basel) ; 22(21)2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36365855

RESUMO

Multiphase machines have recently been promoted as a viable alternative to traditional three-phase machines. Most experts are looking for strategies to estimate the rotation speed of such complex systems, since speed data are required for high-performance control purposes. Traditionally, electromechanical sensors were used to detect the rotor speed of electric motors. These devices are extremely accurate, but they are also delicate and costly to deploy. New speed estimating algorithms must be created for these situations. This paper looks at how to estimate rotor speed in symmetrical six-phase induction motors (IMs) using a novel strategy for rotor speed estimation based on the Short Time Fourier Transform (STFT) method. The technique is based on tracking the frequencies of the rotor slot harmonics (RSH) seen in most squirrel-cage IM stator currents, thus assuring a broad range of applications. To monitor the RSH, the STFT employs a sliding window to perform the discrete Fourier transform technique, making it more suitable for online use with noisy and nonstationary signals. Experimental tests demonstrate the effectiveness of the suggested approach.


Assuntos
Algoritmos , Eletricidade , Análise de Fourier , Rotação
5.
Biofouling ; 37(2): 246-256, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33730946

RESUMO

Microfouling, ie biofilm formation on surfaces, can have an economic impact and requires costly maintenance in water-powered energy generation systems. In this study, the microbiota of a cooling system (filter and heat exchanger) in the Irapé hydroelectric power plant in Brazil was examined. The goal was to identify bacteria that could be targeted to more efficiently reduce biofilm formation. Two sampling campaigns were made corresponding to two well-defined seasons of the Brazilian Cerrado biome: the dry (campaign 1) and the wet (campaign 2). Microfouling communities varied considerably over time in samples obtained at different times after the last clearance of the heat exchanger. The thermophilic bacteria Meiothermus, Thermomonas and Symbiobacterium were exclusive and abundant in the microfouling of the heat exchanger in campaign 2, while methanotrophs and iron-reducing bacteria were abundant only in filter sediments. These findings could help to guide strategies for ecofriendly measures to reduce biofilm fouling in hydroelectric power plants, minimizing environmental and economic losses.


Assuntos
Bactérias , Água , Archaea , Bactérias/genética , Biofilmes , Brasil
6.
Mem Inst Oswaldo Cruz ; 115: e190338, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32130368

RESUMO

Oropouche virus (OROV) is an arthropod-borne virus of the Peribunyaviridae family, transmitted to humans primarily by Culicoides paraensis. It is one of the main arboviruses infecting humans in Brazil, primarily in the Amazon Region. Here, we report the detection of OROV in the saliva and urine of a patient whose samples were collected five days after the onset of symptoms. Nucleotide sequencing and phylogenetic analysis further confirmed the results. To our knowledge, this is the first study reporting the detection of OROV in the saliva and urine of an infected patient. In addition, the results of our study expand the current knowledge pertaining to the natural history of Oropouche fever.


Assuntos
Infecções por Bunyaviridae/diagnóstico , Orthobunyavirus/genética , Orthobunyavirus/isolamento & purificação , Saliva/virologia , Urina/virologia , Sequência de Aminoácidos , Sequência de Bases , Feminino , Humanos , Pessoa de Meia-Idade , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
7.
Eur J Appl Physiol ; 119(4): 921-932, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30689099

RESUMO

PURPOSE: The elite athlete is fine-tuned all around to deliver favorable results in sporting events. In this study, we address the question of whether basic movements-such as reflexes-and heterogeneous attentional modulation components-such as sensorimotor gating mechanisms-are also tuned up to maximize the results of middle-distance runners in physical conditioning tests. METHODS: We selected an array of professional middle-distance runners and healthy counterparts that were submitted to measurement of (1) physical conditioning parameters, including somatotype, jump, strength, and flexibility tests; and (2) sensorimotor gating mechanisms, including acoustic startle reflex, prepulse inhibition, and habituation. RESULTS: Our results showed athletes scored better on the athletic tests compared to controls, as expected. They also exhibited a lower startle amplitude, while maintaining higher prepulse inhibition values. They reacted faster to the acoustic stimuli, and sex-related differences-found in controls-were not present in athletes. Our data also pointed out to substantial correlations between sensorimotor gating and physical conditioning parameters. CONCLUSIONS: All in all, these data may point to physical conditioning-driven neural plasticity of brain sensorimotor gating circuits in charge of triggering involuntary movements to harness control and efficiency over reflexed muscle activity.


Assuntos
Desempenho Atlético/fisiologia , Exercício Físico/fisiologia , Inibição Neural/fisiologia , Filtro Sensorial/fisiologia , Estimulação Acústica/métodos , Adulto , Atenção/fisiologia , Feminino , Humanos , Masculino , Inibição Pré-Pulso/fisiologia , Reflexo de Sobressalto/fisiologia , Caracteres Sexuais , Adulto Jovem
8.
Bull Tokyo Dent Coll ; 58(1): 49-56, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28381734

RESUMO

Ectodermal dysplasia (ED) is an anomaly determined by genetic factors that alter ectodermal structures such as skin, hair, nails, glands, and teeth. Children affected by this condition require extensive, comprehensive, and multidisciplinary treatment. An 8-year-old female patient visited the Dentistry Clinic of the Federal University of Santa Catarina with the chief complaint of multiple missing teeth. The mother reported that the patient had ED. Clinical and radiographic examination revealed the congenital absence of several primary and permanent teeth and tooth germs. Subsequent oral rehabilitation comprised the application of a maxillary denture and mandibular implant-supported fixed prosthesis. The child was also supplied with a wig for further enhancement of esthetics aimed at improving her emotional wellbeing. Psychological follow-up and speech therapy were also provided. After 4 years of follow-up, implant-supported oral rehabilitation has proved to be a satisfactory treatment option, allowing restoration of masticatory, phonetic, and esthetic function, as well as an improvement in the patient's self-esteem and social wellbeing.


Assuntos
Implantes Dentários , Displasia Ectodérmica , Anodontia , Criança , Prótese Dentária Fixada por Implante , Displasia Ectodérmica/terapia , Seguimentos , Humanos , Mandíbula , Maxila
9.
J Prosthodont ; 25(5): 407-10, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26216490

RESUMO

The subject of occlusion has been deemphasized by academia over the last 30 years. This marginalization in turn has negatively impacted recent graduates who are largely unfamiliar with the use of occlusal adjustment by selective reshaping as a treatment modality. Use of proper occlusal therapy enables clinicians to more effectively help patients recover from parafunctional wear of the anterior and posterior teeth. In addition, familiarity with this field enhances the correction of progressive posterior and anterior reverse articulations. This article aims to highlight the importance of occlusal principles in treatment planning. In addition, we illustrate the benefits of occlusal adjustment by using a conservative technique, selective reshaping, as an option to correct anterior reverse articulation in a 20-year-old patient. The knowledge of occlusal principles enhances diagnosis of malocclusion in the development of a treatment plan. When properly employed, the technique of occlusal adjustment by selective reshaping may be used to correct an adaptive anterior reverse articulation with a high degree of predictability for select patients.


Assuntos
Oclusão Dentária , Ajuste Oclusal , Humanos , Má Oclusão , Dente
10.
J Prosthodont ; 24(1): 78-82, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24889364

RESUMO

To treat a patient with anterior crossbite, the clinician should first assess if it is a genuine class III or a pseudo-class III malocclusion. Cephalometric analysis is important; however, registering a patient's centric relation (CR) is simple, quick, and costless and can play a decisive role in a differential diagnosis for this type of patient profile. This clinical report depicts a patient clinically diagnosed as class III. After mandible manipulation in CR, it was noted that the patient in question was a pseudo-class III. The treatment was based on the pseudo-class III diagnosis. Therefore, the patient was rehabilitated by occlusal adjustments and conventional and implant-supported prostheses and without the need for invasive orthognathic surgery.


Assuntos
Relação Central , Má Oclusão Classe III de Angle/diagnóstico , Má Oclusão/diagnóstico , Cefalometria , Humanos , Masculino , Má Oclusão/fisiopatologia , Má Oclusão/reabilitação , Má Oclusão Classe III de Angle/fisiopatologia , Má Oclusão Classe III de Angle/reabilitação , Mandíbula/fisiopatologia , Maxila/fisiopatologia , Pessoa de Meia-Idade
11.
Eur J Prosthodont Restor Dent ; 22(4): 153-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26466439

RESUMO

The objective of this study was to evaluate the ability of dental specialists to distinguish lateral incisor metal-free from porcelain-fused-to-metal implant supported crowns in the anterior region. Five single-tooth implants in the maxillary lateral incisor region were restored with two types of implant-supported crowns (porcelain-fused-to-metal and metal-free). Photographs were presented to 20 evaluators. The evaluators had to answer whether the crown was: metal-free, porcelain-fused-to-metal or they could not tell the difference. The results showed that groups 1 (all participants), 3 (Restorative & Prosthodontic specialists), 4 (graduated 10 years) and 5 (graduated > 10 years) failed to respond correctly (P > 0.05) to which type of crown was presented to them. Group 2 (Periodontology & Implantology specialists) showed an accuracy rate of 35.6% (P = 0.009), in relation to metal-free crowns, 5.6 which is below the random index. The authors concluded that the evaluators from the 5 groups studied were unable to significantly distinguish which type of crown was used in the 10 presented situations.


Assuntos
Coroas , Implantes Dentários para Um Único Dente , Materiais Dentários/química , Porcelana Dentária/química , Prótese Dentária Fixada por Implante , Odontólogos , Ligas Metalo-Cerâmicas/química , Especialidades Odontológicas , Zircônio/química , Ligas de Cromo/química , Tomada de Decisões , Implantação Dentária , Planejamento de Prótese Dentária , Dentística Operatória , Humanos , Incisivo , Maxila , Periodontia , Fotografia Dentária , Prostodontia
12.
Cureus ; 16(3): e55838, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38590492

RESUMO

Biliothorax is the presence of bile in the pleural cavity. This condition is rare, and it usually results as a complication of hepatobiliary procedures. The authors present a case of an 87-year-old female who was admitted to the emergency department with the acute onset of severe dyspnea. A chest X-ray and CT revealed a large right-lung pleural effusion that, after thoracentesis, confirmed the presence of biliothorax. It is important to consider this entity when confronted with an effusion liquid of a dark greenish color, as a delay in diagnosis and management may be life-threatening.

13.
Braz J Microbiol ; 55(1): 639-646, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38214875

RESUMO

Iron (Fe) is the fourth most abundant element on the planet, and iron-oxidising bacteria (FeOB) play an important role in the biogeochemical cycle of this metal in nature. FeOB stands out as Fe oxidisers in microaerophilic environments, and new members of this group have been increasingly discussed in the literature, even though their isolation can still be challenging. Among these bacteria is the Gallionellaceae family, mainly composed of neutrophilic FeOB, highlighting Gallionella ferruginea, and nitrite-oxidiser genera. In the previous metagenomic study of the biofilm and sediments of the cooling system from the Irapé hydroelectric power plant (HPP-Irapé), 5% of the total bacteria sequences were related to Gallionellaceae, being 99% unclassified at genus level. Thus, in the present study, a phylogenetic tree based on this family was constructed, in order to search for shared and unique Gallionellaceae signatures in a deep phylogenetic level affiliation and correlated them with geomorphologic characteristics. The results revealed that Gallionella and Ferrigenium were ubiquitous reflecting their ability to adapt to various locations in the power plant. The cave was considered a hotspot for neutrophilic FeOB since it harboured most of the Gallionellaceae diversity. Microscopic biosignatures were detected only in the CS1 sample, which presented abundance of the stalk-forming Ferriphaselus and of the sheath-forming Crenothrix. Further studies are required to provide more detailed insights on Gallionellaceae distribution and diversity patterns in hydroelectric power plants, particularly its biotechnological potential in this industry.


Assuntos
Gallionellaceae , Gallionellaceae/genética , Filogenia , Ferro , Metais , Metagenômica , Oxirredução
14.
PLoS One ; 19(6): e0300445, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38924000

RESUMO

The study investigates the efficacy of a bioinspired Particle Swarm Optimization (PSO) approach for PID controller tuning in Radiofrequency Ablation (RFA) for liver tumors. Ex-vivo experiments were conducted, yielding a 9th order continuous-time transfer function. PSO was applied to optimize PID parameters, achieving outstanding simulation results: 0.605% overshoot, 0.314 seconds rise time, and 2.87 seconds settling time for a unit step input. Statistical analysis of 19 simulations revealed PID gains: Kp (mean: 5.86, variance: 4.22, standard deviation: 2.05), Ki (mean: 9.89, variance: 0.048, standard deviation: 0.22), Kd (mean: 0.57, variance: 0.021, standard deviation: 0.14) and ANOVA analysis for the 19 experiments yielded a p-value ≪ 0.05. The bioinspired PSO-based PID controller demonstrated remarkable potential in mitigating roll-off effects during RFA, reducing the risk of incomplete tumor ablation. These findings have significant implications for improving clinical outcomes in hepatocellular carcinoma management, including reduced recurrence rates and minimized collateral damage. The PSO-based PID tuning strategy offers a practical solution to enhance RFA effectiveness, contributing to the advancement of radiofrequency ablation techniques.


Assuntos
Neoplasias Hepáticas , Ablação por Radiofrequência , Neoplasias Hepáticas/cirurgia , Ablação por Radiofrequência/métodos , Humanos , Carcinoma Hepatocelular/cirurgia , Animais , Algoritmos , Simulação por Computador , Ablação por Cateter/métodos
15.
Braz J Microbiol ; 54(3): 1547-1557, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37301793

RESUMO

Microfouling can have significant economic impacts for hydroelectric power plants. However, knowledge concerning the composition and metabolism of microbial biofilm in cooling systems remains scarce. We examined the metagenome present in a cooling system, comprising a filter (F) and heat exchanger (HE), in the Nova Ponte hydroelectric power plant in Brazil, to identify bacteria and pathways that could be targeted to monitor and control biofilm formation. Our data revealed that the microfouling sample from heat exchanger 1 (HEM1), with porous consistency, presented enriched bacterial members not frequently described as biofilm formers in cooling systems, besides it has been shown to be an autoinducer repression pathway. Furthermore, the microfouling sample from heat exchanger 2 (HEM2), with gelatinous consistency, seemed to be an established biofilm, containing enriched bacterial groups such as Desulfotomaculum and Crenothrix and autoinducers, with biotechnological relevance in industrial biofilms. The results demonstrate that biofilm composition will vary depending on different abiotic conditions and the antifouling strategy used, including type of compound, concentration, and frequency of use. Therefore, all these variables must be evaluated when a power plant is affected by microbial slime in the cooling system. Our findings could help to define strategies for efficient and ecofriendly measures to contain microfouling in power plants.


Assuntos
Incrustação Biológica , Incrustação Biológica/prevenção & controle , Biofilmes , Bactérias/genética , Brasil , Percepção de Quorum
16.
Psicol Reflex Crit ; 36(1): 12, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37195397

RESUMO

PURPOSE: To test the feasibility, reliability, and validity of the Satisfaction with Life Scale (SWLS) in an online format in university students from a low-income region. METHODS: This was a psychometric study, involving a study of reliability (n = 117) and validity (n = 195) in university students from a region with a Gini index of 0.56. The scale was applied at two time points with an interval of 2 weeks. This scale measures satisfaction with life based on five statements and responses ranging from 1 to 7 (strongly disagree to strongly agree). We conducted the reliability assessment using temporal stability and internal consistency and construct validity assessment by internal structure solution. RESULTS: All SWLS items showed acceptable (rho > 0.30) and significant (p < 0.05) temporal stability and acceptable internal consistency (alpha > 0.70). In construct validity (internal structure), we identified a factor with an explained variance of 59.0% in the exploratory factor analysis. Additionally, in the confirmatory factor analysis, we identified a one-factor structure solution for SWLS with an acceptable model fitting (chi-square/degrees of freedom [X2/df] = 6.53; Tucker-Lewis Index [TLI] = 0.991; Comparative Fit Index [CFI] = 0.996; root mean square error of approximation [RMSEA] = 0.040; standardized root mean-squared residual [SRMR] = 0.026). CONCLUSION: The Satisfaction with Life Scale, in the online format, is a reliable and valid tool for university students in a low-income context.

17.
Animals (Basel) ; 13(20)2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37893982

RESUMO

Limnoperna fortunei, the golden mussel, is a bivalve mollusk considered an invader in South America. This species is responsible for ecological and economic damages due to its voluminous fouling capability. Chemical biocides such as MXD-100™ and sodium dichloroisocyanurate (NaDCC) are often used to control L. fortunei infestations in hydraulic systems. Thus, we proposed to investigate the effects of different periods (24, 48 and 72 h) of exposure to MXD-100™ (0.56 mg L-1) and NaDCC (1.5 mg L-1) on the gills of L. fortunei through morphological and molecular analyses. NaDCC promoted progressive morphological changes during the analyzed periods and only an upregulation of SOD and HSP70 expression during the first 24 h of exposure. MXD-100™ led to severe morphological changes from the first period of exposure, in addition to an upregulation of SOD, CAT, HSP70 and CYP expression during the first 24 h. In contrast, MXD-100™ led to a downregulation of CAT transcription between 24 and 48 h. In static conditions, NaDCC causes lethal damage after 72 h of exposure, and that exposure needs to be continuous to achieve the control of the species. Meanwhile, the MXD-100™ treatment presented several effects during the first 24 h, showing acute toxicity in a shorter period of time.

18.
Clin Oral Implants Res ; 23(12): 1360-8, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22117899

RESUMO

OBJECTIVES: This study assessed the fatigue resistance and failure mode of porcelain and composite resin crowns and onlays bonded to premolar custom zirconia implant abutments. MATERIALS AND METHODS: Sixty standardized zirconia implant abutments were milled (NeoShape) according to two different restoration designs (onlay or crown). Using Cerec 3, the corresponding onlays and crowns were fabricated either in ceramic (Paradigm C) or composite resin (Paradigm MZ100), resulting in four experimental groups (n = 15). The fitting surfaces of the abutments were airborne-particle abraded and cleaned. The intaglio surfaces of the restorations were HF-etched and silanated (Paradigm C) or airborne-particle abraded and silanated (Paradigm MZ100). Following insertion of the abutments into a Morse taper implant (Titamax CM), all restorations were bonded with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL), and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 50N (5000×), followed by stages of 200N, 400N, 600N, 800N, 1000N, 1200N, and 1400N (25,000× each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using the life table survival analysis (Logrank test at P = 0.05). RESULTS: All composite resin onlays and crowns survived (100% survival rate), while ceramic ones fractured at an average load of 1347N and 1280N, respectively, (survival rate of 46.7% and 20%) with a significant difference in survival probability (P < 0.0001). Fractures consisted in partial or total failure of the restoration only (no abutment failure, no screw loosening). CONCLUSIONS: Composite resin onlays and crowns bonded to custom zirconia implant abutments presented a significant higher survival rate when compared to ceramic onlays and crowns.


Assuntos
Resinas Compostas/química , Coroas , Dente Suporte , Porcelana Dentária/química , Falha de Restauração Dentária , Restaurações Intracoronárias , Zircônio/química , Condicionamento Ácido do Dente , Cerâmica/química , Desenho Assistido por Computador , Colagem Dentária , Planejamento de Prótese Dentária , Análise do Estresse Dentário , Cimentos de Resina/química
19.
J Esthet Restor Dent ; 24(2): 135-46, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22524722

RESUMO

STATEMENT OF PROBLEM: Cracked teeth may traditionally require the use of complete coverage crowns. Alternative conservative treatments involve the use of adhesive inlays/onlays with the possibility of including a fiber patch to reinforce the cracked cusp. PURPOSE: The purpose of this study was to evaluate the fatigue strength of compromised molars restored with computer-aided-design/computer-assisted-manufactured (CAD/CAM) composite resin inlays/onlays with and without fiber-reinforced immediate dentin sealing (IDS). METHODS AND MATERIALS: Large mesio-occluso-distal preparations with cracked/undermined palatal cusps were simulated on 40 extracted maxillary molars. All teeth received IDS (Optibond FL, Kerr, Orange, CA, USA), and composite resin (Paradigm MZ100, 3M-ESPE, St. Paul, MN, USA) inlays (N = 20) and onlays (N = 20). A fiber patch (Ribbond, Ribbond Inc., Seattle, WA, USA) was applied in half of the preparations. Restorations were adhesively luted with pre-heated composite resin (Z100, 3-M ESPE) and submitted to cyclic isometric loading at 5 Hz, starting with a load of 50 N (5,000 cycles), followed by stages of 150, 300, 450, 600, 750, 900, and 1,050 N at a maximum of 25,000 cycles each. Specimens were loaded until fracture or to a maximum of 180,000 cycles. Groups were compared using the life table survival analysis. RESULTS: Differences in survival probability were found (p = 0.04). The inlay group with fiber patch failed at an average load of 870 N, and none of the specimens withstood all 180,000 load cycles; survival rates of inlays and onlays without fibers, and onlays with fibers were 10, 30, and 50%, respectively. CONCLUSIONS: Onlays (with or without fibers) increased the fatigue resistance of compromised molars in this in vitro study.


Assuntos
Desenho Assistido por Computador , Síndrome de Dente Quebrado/terapia , Planejamento de Prótese Dentária , Restaurações Intracoronárias , Cimentos de Resina/uso terapêutico , Coroa do Dente/lesões , Resinas Compostas/química , Falha de Restauração Dentária , Análise do Estresse Dentário , Humanos , Dente Molar/lesões , Polietilenos , Análise de Sobrevida
20.
Molecules ; 17(5): 4904-14, 2012 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-22543505

RESUMO

This study investigated the potential of Rhizopus arrhizus UCP 402 for producing chitosan using corn steep liquor and honey as agroindustrial nitrogen and carbon sources. A complete factorial design was used to assess the improved biomass and chitosan production. The results were evaluated using Pareto charts (Statistica 7.0 software). The chitosan obtained was characterized by X-ray diffraction. The cristallinity index (I(C)), and infrared spectroscopy (FTIR) were used to evaluate the degree of deacetylation (DD %). The morphological aspects of the R. arrhizus were evaluated by measuring the diameter of the colonies by light microscopy. The results obtained showed higher biomass and chitosan yields (20.61 g/L and 29.3 mg/g), respectively, in the selected assays. The characterization of the macromolecular arrangement of chitosan showed a crystallinity index compatible with the literature, and the infrared peaks confirmed a degree of 86%. The experimental data obtained suggest that adding honey to corn steep liquor is a promising way to improve microbiological chitosan production.


Assuntos
Quitosana/metabolismo , Produtos Agrícolas/metabolismo , Rhizopus/metabolismo , Biomassa , Carbono , Cristalização , Mel , Microscopia , Nitrogênio , Rhizopus/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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