Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 181
Filtrar
1.
Sci Rep ; 11(1): 3560, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33574395

RESUMO

The PolariX TDS (Polarizable X-Band Transverse Deflection Structure) is an innovative TDS-design operating in the X-band frequency-range. The design gives full control of the streaking plane, which can be tuned in order to characterize the projections of the beam distribution onto arbitrary transverse axes. This novel feature opens up new opportunities for detailed characterization of the electron beam. In this paper we present first measurements of the Polarix TDS at the FLASHForward beamline at DESY, including three-dimensional reconstruction of the charge-density distribution of the bunch and slice emittance measurements in both transverse directions. The experimental results open the path toward novel and more extensive beam characterization in the direction of multi-dimensional-beam-phase-space reconstruction.

2.
Phys Rev Lett ; 127(26): 266802, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029471

RESUMO

Microscopic insight into interactions is a key for understanding the properties of heterogenous interfaces. We analyze local attraction in noncovalently bonded Xe-Cs^{+} aggregates and monolayers on Cu(111) as well as repulsion upon electron transfer. Using two-photon photoemission spectroscopy, scanning tunneling microscopy, and coupled cluster calculations combined with an image-charge model, we explain the intricate impact Xe has on Cs^{+}/Cu(111). We find that attraction between Cs^{+} and Xe counterbalances the screened Coulomb repulsion between Cs^{+} ions on Cu(111). Furthermore, we observe that the Cs 6s electron is repelled from Cu(111) due to xenon's electron density. Together, this yields a dual, i.e., attractive or repulsive, response of Xe depending on the positive or negative charge of the respective counterparticle, which emphasizes the importance of the Coulomb interaction in these systems.

3.
Orthod Craniofac Res ; 18 Suppl 1: 146-55, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25865543

RESUMO

OBJECTIVE: To determine differences in masticatory muscle usage between temporomandibular joint disorders diagnostic groups. SETTING AND SAMPLE POPULATION: Seventy-one informed and consented subjects (27 men; 44 women) participated at the University at Buffalo. MATERIAL AND METHODS: Research diagnostic criteria and imaging data were used to categorize subjects according to the presence/absence +/- of TMJ disc placement (DD) and chronic pain (P) (+DD+P, n=18; +DD-P, n=14; -DD-P, n=39). Electromyographic (EMG)/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20 N bite-force (T20N , µV). Over 3 days and nights, subjects collected EMG recordings. Duty factors (DFs, % of recording time) were determined based on threshold intervals (5-9, 10-24, 25-49, 50-79, ≥80% T20N ). anova and Tukey-Kramer post hoc tests identified 1) diagnostic group differences in T20N and 2) the effects of diagnostic group, gender, time and interval on muscle DFs. RESULTS: Mean (±SE) temporalis T20N in +DD+P subjects was significantly higher (71.4±8.8 µV) than masseter T20N in these subjects (19.6±8.8 µV; p=0.001) and in -DD-P subjects (25.3±6.0 µV, p=0.0007). Masseter DFs at 5-9% T20N were significantly higher in +DD-P women (3.48%) than +DD-P men (0.85%) and women and men in both other diagnostic groups (all p<0.03), and in +DD+P women (2.00%) compared to -DD-P men (0.83%; p=0.029). Night-time DFs at 5-9% T20N in +DD-P women (1.97%) were significantly higher than in -DD-P men (0.47%) and women (0.24%; all p<0.01). CONCLUSIONS: Between-group differences were found in masticatory muscle activities in both laboratory and natural environmental settings.


Assuntos
Eletromiografia/métodos , Músculo Masseter/fisiopatologia , Monitorização Ambulatorial/métodos , Músculo Temporal/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Adulto , Força de Mordida , Dor Crônica/fisiopatologia , Dor Facial/fisiopatologia , Feminino , Humanos , Luxações Articulares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Tono Muscular/fisiologia , Projetos Piloto , Fatores Sexuais , Sono/fisiologia , Disco da Articulação Temporomandibular/patologia , Transtornos da Articulação Temporomandibular/classificação , Síndrome da Disfunção da Articulação Temporomandibular/fisiopatologia , Adulto Jovem
4.
Orthod Craniofac Res ; 18 Suppl 1: 164-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25865545

RESUMO

OBJECTIVES: Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm³) in TMJs of three diagnostic groups. SETTING AND SAMPLE POPULATION: Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD). MATERIAL AND METHODS: Subjects (+P+DD, n=16; -P+DD, n=16; and -P-DD, n=36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q (W=work done or mechanical energy input=tractional force×distance of stress-field translation, Q=volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences. RESULTS: Mean±standard error energy density for the +P+DD group was 12.7±1.5 mJ/mm³ and significantly greater (all adjusted p<0.04) when compared to -P+DD (7.4±1.4 mJ/mm³) and -P-DD (5.8±0.9 mJ/mm³) groups. Energy densities in -P+DD and -P-DD groups were not significantly different. CONCLUSION: Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.


Assuntos
Cartilagem Articular/fisiopatologia , Transtornos da Articulação Temporomandibular/classificação , Adulto , Artralgia/fisiopatologia , Fenômenos Biomecânicos , Simulação por Computador , Tomografia Computadorizada de Feixe Cônico/métodos , Dor Facial/fisiopatologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Luxações Articulares/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Masculino , Modelos Biológicos , Amplitude de Movimento Articular/fisiologia , Estresse Mecânico , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Síndrome da Disfunção da Articulação Temporomandibular/fisiopatologia , Trabalho/fisiologia
5.
Orthod Craniofac Res ; 18 Suppl 1: 170-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25865546

RESUMO

OBJECTIVES: Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. SETTING AND SAMPLE POPULATION: School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). MATERIAL AND METHODS: Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations. RESULTS: +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p<0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8). CONCLUSION: Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.


Assuntos
Músculos da Mastigação/fisiopatologia , Modelos Biológicos , Transtornos da Articulação Temporomandibular/fisiopatologia , Fenômenos Biomecânicos , Força de Mordida , Simulação por Computador , Feminino , Humanos , Incisivo/fisiopatologia , Luxações Articulares/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Masculino , Músculo Masseter/fisiopatologia , Dente Molar/fisiopatologia , Músculos Pterigoides/fisiopatologia , Estresse Mecânico , Músculo Temporal/fisiopatologia , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/classificação , Síndrome da Disfunção da Articulação Temporomandibular/fisiopatologia , Tomografia Computadorizada por Raios X/métodos
6.
J Environ Manage ; 120: 138-47, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23524327

RESUMO

Can markets assist by providing support for ecological restoration, and if so, under what conditions? The first step in addressing this question is to develop a consistent methodology for economic evaluation of ecological restoration projects. A risk analysis process was followed in which a system dynamics model was constructed for eight diverse case study sites where ecological restoration is currently being pursued. Restoration costs vary across each of these sites, as do the benefits associated with restored ecosystem functioning. The system dynamics model simulates the ecological, hydrological and economic benefits of ecological restoration and informs a portfolio mapping exercise where payoffs are matched against the likelihood of success of a project, as well as a number of other factors (such as project costs and risk measures). This is the first known application that couples ecological restoration with system dynamics and portfolio mapping. The results suggest an approach that is able to move beyond traditional indicators of project success, since the effect of discounting is virtually eliminated. We conclude that systems dynamic modelling with portfolio mapping can guide decisions on when markets for restoration activities may be feasible.


Assuntos
Conservação dos Recursos Naturais/métodos , Monitoramento Ambiental/métodos , Modelos Teóricos , Medição de Risco , África do Sul
7.
J Periodontal Res ; 48(5): 541-8, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23278592

RESUMO

BACKGROUND AND OBJECTIVE: Local host-modulation therapy is an emerging approach to prevent disease progression in sites with moderate periodontitis. The combination of simvastatin and alendronate would be an intriguing host-modulatory strategy because of the bone-anabolic properties of simvastatin and the antiresorptive/bone-targeting characteristics of alendronate. The objective of this study was to evaluate the effects of local administration of a simvastatin-alendronate-ß-cyclodextrin (SIM-ALN-CD) conjugate for preventing experimental periodontitis bone loss. MATERIAL AND METHODS: Twenty-four mature female Sprague-Dawley rats were treated with three, 12 µL injections, administered one week apart, bilaterally into the palatal/interproximal gingiva. The injections contained: (i) a conjugate of 0.5 mg of SIM and 3.75 mg of ALN-CD in H2 O; (ii) H2 O alone; or (iii) no treatment. One week later, the same sites were subjected to induction of experimental periodontitis by three injections (i.e. one injection administered every other day for five d) of 0.01 mg of Escherichia coli endotoxin [lipopolysaccharide (LPS)] in phosphate-buffered saline (PBS) or PBS alone. After an additional week, the rats were killed, the palates were harvested and interproximal bone volume and adjacent thickness were calculated using microcomputed tomography. Subsequently, specimens were decalcified, and interproximal histologic sections were stained with hematoxylin and eosin for evaluation of alveolar crest osteoclasts and surrounding inflammation. Values were compared among treatment groups using analysis of variance and the Kruskal-Wallis test. RESULTS: Interproximal bone volume was reduced by LPS injections (p ≤ 0.04), yet when experimental periodontitis was preceded by treatment with SIM-ALN-CD, more bone was preserved than after treatment with carrier alone (p = 0.007). While LPS caused a significant loss in bone thickness over the palatal roots (p ≤ 0.04), the injection protocol (PBS) also caused a significant loss of palatal bone thickness (p ≤ 0.03). However, prophylactic SIM-ALN-CD injections resulted in no further loss of bone thickness during experimental periodontitis. LPS injections gave histologic evidence of increased osteoclasts and subsulcular inflammation, both of which were reduced when preceded by treatment with SIM-ALN-CD (p ≤ 0.0002). CONCLUSION: The primary conclusion of this study was that locally applied SIM-ALN-CD has the potential to prevent episodes of periodontitis bone loss.


Assuntos
Alendronato/administração & dosagem , Perda do Osso Alveolar/prevenção & controle , Conservadores da Densidade Óssea/administração & dosagem , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Periodontite/prevenção & controle , Sinvastatina/administração & dosagem , Perda do Osso Alveolar/microbiologia , Animais , Combinação de Medicamentos , Endotoxinas/farmacologia , Escherichia coli , Feminino , Imageamento Tridimensional/métodos , Injeções , Lipopolissacarídeos/farmacologia , Doenças Maxilares/microbiologia , Doenças Maxilares/prevenção & controle , Dente Molar/microbiologia , Dente Molar/patologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/patologia , Palato/microbiologia , Palato/patologia , Periodontite/microbiologia , Pré-Medicação , Ratos , Ratos Sprague-Dawley , Sequestrantes/administração & dosagem , Microtomografia por Raio-X/métodos , beta-Ciclodextrinas/administração & dosagem
8.
J Dent Res ; 91(6): 568-73, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22522774

RESUMO

Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. Evaluations of diagnostic group and gender effects on choice of best-fit model were by analysis of variance (ANOVA) and Tukey-Kramer post hoc tests, evaluations of right-left symmetry were by Chi-square and Fisher's exact statistics, and evaluations of model accuracy were by within-subject linear regressions. MME was the best-fit during left molar biting in +DD individuals and incisor biting in men (all p < 0.03). Incisor biting symmetry in muscle organization was significantly higher (p < 0.03) in healthy individuals compared with those with TMD. Within-subject regressions showed that best-fit model errors were similar among groups: 8 to 15% (0.68 ≤ R(2) ≤ 0.74). These computer-assisted models predicted muscle organization during static biting in humans with and without TMDs.


Assuntos
Força de Mordida , Simulação por Computador , Dor Facial/fisiopatologia , Músculos da Mastigação/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Adulto , Fenômenos Biomecânicos , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , Análise do Estresse Dentário , Eletromiografia , Feminino , Humanos , Luxações Articulares , Modelos Lineares , Masculino , Músculos da Mastigação/fisiologia , Pessoa de Meia-Idade , Modelos Biológicos , Adulto Jovem
9.
J Biomed Biotechnol ; 2011: 761593, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21274404

RESUMO

The aim of this study was assess the effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Second-degree burn wounds were performed in forty-five Wistar rats, assigned into nine groups: COL-animals treated with collagen-based films; PHO-animals treated with collagen films containing empty liposomes; UAL-animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14, and 21 days the animals were euthanized. On 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltration. On the 21st day, there was reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of the usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats.


Assuntos
Benzofuranos/administração & dosagem , Curativos Biológicos , Queimaduras/terapia , Colágeno/administração & dosagem , Lipossomos/administração & dosagem , Cicatrização/efeitos dos fármacos , Actinas/metabolismo , Animais , Queimaduras/metabolismo , Queimaduras/patologia , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Imuno-Histoquímica , Inflamação/patologia , Inflamação/prevenção & controle , Masculino , Miofibroblastos/metabolismo , Ratos , Ratos Wistar
10.
J Dent Res ; 89(7): 722-7, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20554892

RESUMO

Analysis of previous data suggested the hypothesis that temporomandibular joint (TMJ) eminence shapes develop ideally to minimize joint loads. Hence, we tested this hypothesis in nine females and eight males in each of two groups, with and without TMJ disc displacement. Participants provided anatomical data used in a joint load minimization numerical model to predict, and jaw-tracking data used to measure, eminence shapes. Coordinate data (x,y) of shapes were fit to third-order polynomials for two sessions, sides, and methods (predicted, measured) for each participant. Inter-session data were reliable and averaged. Those with, compared with those without, disc displacement had higher measured shape range (5:1) and left-right asymmetry prevalence (4:1). In 29 symmetrical individuals, ANCOVA and Bonferroni tests compared vertical dimensions (y) at 11 postero-anterior points (x), 0.5 mm apart. Model-predicted and measured shapes were significantly different (P < or = 0.01) near the eminence crest, but joint load minimization was consistent with eminence shape for x < 3.0 mm.


Assuntos
Luxações Articulares/patologia , Côndilo Mandibular/patologia , Disco da Articulação Temporomandibular/patologia , Transtornos da Articulação Temporomandibular/patologia , Suporte de Carga/fisiologia , Adulto , Fenômenos Biomecânicos , Estudos Transversais , Oclusão Dentária , Assimetria Facial/patologia , Assimetria Facial/fisiopatologia , Feminino , Humanos , Luxações Articulares/fisiopatologia , Masculino , Côndilo Mandibular/fisiopatologia , Músculos da Mastigação/patologia , Músculos da Mastigação/fisiopatologia , Pessoa de Meia-Idade , Modelos Biológicos , Amplitude de Movimento Articular/fisiologia , Estresse Mecânico , Articulação Temporomandibular/patologia , Articulação Temporomandibular/fisiopatologia , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Dimensão Vertical , Adulto Jovem
11.
J Dent Res ; 88(8): 736-40, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19734461

RESUMO

Tractional forces on the temporomandibular joint (TMJ) disc predispose tissue fatigue. This study tested the hypotheses that tractional forces: (1) increased with stress-field velocity (V) and aspect ratio (AR, contact area diameter/cartilage thickness), and compressive strain (epsilon); and (2) varied depending on cartilage thickness. Porcine TMJ discs (n = 187) received a 10-N vertical static load via an acrylic indenter for 1, 5, 10, 30, or 60 sec, followed by movement. Physical data were recorded and analyzed by quadratic regression relations and a likelihood ratio test. Results showed non-linear increases in tractional forces that were positively correlated with increased V, AR, and epsilon when the stress-field moved onto relatively thicker (R(2) = 0.83) and thinner cartilage (R(2) = 0.86). When V was > 27 mm/sec and AR.epsilon(3), was > 0.09, tractional forces were significantly higher (< or = 12% of peak) when the stress-field moved onto thicker cartilage. Stress-field dynamic mechanics and cartilage thickness significantly affected TMJ disc tractional forces.


Assuntos
Disco da Articulação Temporomandibular/fisiopatologia , Algoritmos , Animais , Fenômenos Biomecânicos , Cartilagem Articular/patologia , Cartilagem Articular/fisiopatologia , Rotação , Estresse Mecânico , Suínos , Disco da Articulação Temporomandibular/patologia , Tração
12.
Orthod Craniofac Res ; 12(3): 159-67, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19627517

RESUMO

OBJECTIVES - To determine the combined effects 1) of stress-field aspect ratio and velocity and compressive strain and 2) joint load, on temporomandibular joint (TMJ) disc mechanics. SETTING AND SAMPLE POPULATION - Fifty-two subjects (30 female; 22 male) participated in the TMJ load experiments. MATERIAL AND METHODS - In the absence of human tissue, pig TMJ discs were used to determine the effects of variables 1) on surface plowing forces, and to build a biphasic finite element model (bFEM) to test the effect of human joint loads and 2) on tissue stresses. In the laboratory, discs received a 7.6 N static load via an acrylic indenter before cyclic movement. Data were recorded and analysed using anova. To determine human joint loads, Research Diagnostic Criteria calibrated investigators classified subjects based on signs of disc displacement (DD) and pain (+DD/+pain, n = 18; +DD/-pain, n = 17; -DD/-pain, n = 17). Three-dimensional geometries were produced for each subject and used in a computer model to calculate joint loads. RESULTS - The combined effects of compressive strain, and aspect ratio and velocity of stress-field translation correlated with plowing forces (R(2) = 0.85). +DD/-pain subjects produced 60% higher joint loads (ANOVA, p < 0.05), which increased bFEM-calculated compressive strain and peak total normal stress. CONCLUSIONS - Static and dynamic variables of the stress-field and subject-dependent joint load significantly affect disc mechanics.


Assuntos
Disco da Articulação Temporomandibular/fisiologia , Adulto , Animais , Fenômenos Biomecânicos , Força de Mordida , Simulação por Computador , Módulo de Elasticidade , Dor Facial/fisiopatologia , Feminino , Análise de Elementos Finitos , Humanos , Luxações Articulares/fisiopatologia , Masculino , Músculo Masseter/fisiopatologia , Fenômenos Mecânicos , Pessoa de Meia-Idade , Modelos Animais , Músculos do Pescoço/fisiopatologia , Permeabilidade , Músculos Pterigoides/fisiopatologia , Estresse Mecânico , Suínos , Músculo Temporal/fisiopatologia , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Suporte de Carga/fisiologia , Adulto Jovem
13.
Orthod Craniofac Res ; 12(2): 129-40, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19419456

RESUMO

OBJECTIVES: To investigate genetic, biologic, and mechanical factors that affect speed of human tooth movement. Setting and Sample Population - Sixty-six maxillary canines in 33 subjects were translated distally for 84 days. MATERIAL AND METHODS: Distal compressive stresses of 4, 13, 26, 52, or 78 kPa were applied to maxillary canines via segmental mechanics. Dental casts and gingival crevicular fluid (GCF) samples were collected nine to 10 times/subject over 84 days at 1- to 14-day intervals. Three-dimensional tooth movements were measured using a microscope and each subject's series of dental casts. GCF samples were analyzed for total protein, interleukin-1beta (IL-1beta), and interleukin-1 receptor antagonist (IL-1RA). Cheek-wipe samples from 18 subjects were typed for IL-1 gene cluster polymorphisms. RESULTS: Average speeds of distal translation were 0.028 +/- 0.012, 0.043 +/- 0.019, 0.057 +/- 0.024, 0.062 +/- 0.015, and 0.067 +/- 0.024 mm/day for 4, 13, 26, 52, and 78 kPa, respectively. Most teeth moved showed no lag phase (63/66). Three factors significantly affected speed (p = 0.0391) and provided the best predictive model (R(2) = 0.691): Activity index [AI = experimental (IL-1beta/IL-1RA)/control (IL-1beta/IL-1RA)], IL-1RA in GCF, and genotype at IL-1B. CONCLUSIONS: Increased AI and decreased IL-1RA in GCF plus having > or =1 copy of allele 2 at IL-1B(+3954) were associated with faster tooth movement in humans.


Assuntos
Líquido do Sulco Gengival/imunologia , Interleucina-1/genética , Polimorfismo Genético/genética , Técnicas de Movimentação Dentária , Adolescente , Adulto , Alelos , Pareamento de Bases/genética , Criança , Dente Canino/patologia , Feminino , Genótipo , Líquido do Sulco Gengival/metabolismo , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Proteína Antagonista do Receptor de Interleucina 1/análise , Interleucina-1alfa/análise , Interleucina-1beta/análise , Masculino , Repetições Minissatélites/genética , Proteínas/análise , Rotação , Estresse Mecânico , Fatores de Tempo , Coroa do Dente/patologia , Torque , Adulto Jovem
14.
J Chem Phys ; 130(14): 144703, 2009 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-19368461

RESUMO

The adsorption of CO on the rutile TiO(2)(110) surface was investigated using He atom scattering (HAS), high resolution electron energy loss spectroscopy (HREELS), thermal desorption spectroscopy (TDS), and different types of ab initio electronic structure calculations. The experimental and theoretical results allow to put forward a consistent picture for this rather complicated adsorbate system. At 70 K a (2x1) adlayer with a glide symmetry plane is formed, containing two molecules per unit cell which are tilted in alternate directions by about 20 degrees relative to the surface normal. For this high density phase, the theoretical calculations reveal a substantial repulsion between CO molecules on neighboring lattice sites, in accord with the results of a detailed analysis of the experimental TDS data. The CO binding energy depends strongly on coverage and varies between 0.20 eV for the saturated monolayer and 0.36 eV for isolated molecules. The CO-CO repulsion leads to the desorption of about half of the CO molecules above 70 K and the formation of low density phases. HAS gave no indication of ordered adlayers at these lower coverages. For the internal stretching vibration of the CO molecules a value of 273 meV was determined by HREELS, in very good agreement with the theoretical calculations.

15.
Arch Oral Biol ; 53(2): 199-205, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18031712

RESUMO

Static mechanical analyses of the masticatory apparatus often assume that jaw muscle activity, as measured using electromyography (EMG), is linearly and constantly related to magnitude of bite force during biting, regardless of bite force-induced tooth-tipping moments. The objective of this study was to test the hypothesis that the relationship between EMG of the jaw muscles and bite force varies with the magnitude and sign of tooth-tipping moments. Seven healthy male subjects produced unilateral static occlusal forces at five biting positions, resulting in sequential changes from buccal (+) to lingual (-) tipping moments on the mandibular first molar. Jaw muscle activities were recorded bilaterally using surface (for temporalis and masseter muscles) and indwelling (for lateral pterygoid muscles) electrodes. Bite forces were recorded and controlled using custom devices. EMG versus bite force data were plotted and regression relationships were calculated for each subject, muscle and biting position. Linear regression analysis, analysis of variance and Bonferroni adjusted least significant difference tests were used to determine the effects of muscle, side (ipsilateral, contralateral) and biting position within subjects. It was found that the relationship between EMG and bite force for different tipping moments differed significantly within a subject and muscle. This was most common in the lateral pterygoid and temporalis muscles (all P25:1. In the masseter muscle, the EMG:bite force relationship for different tipping moments differed significantly in one subject (P<0.008); slopes varied up to 4.6:1. In conclusion, the relationship between EMG and bite force was linear. However, the slopes of the relationship changed significantly depending on sign (+, -) and magnitude of tipping moments acting on the molars.


Assuntos
Oclusão Dentária , Arcada Osseodentária/fisiologia , Músculos da Mastigação/fisiologia , Dente , Adulto , Análise de Variância , Fenômenos Biomecânicos/métodos , Força de Mordida , Eletromiografia/métodos , Humanos , Arcada Osseodentária/patologia , Masculino , Músculos da Mastigação/patologia
16.
J Periodontal Res ; 42(3): 267-73, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17451547

RESUMO

BACKGROUND AND OBJECTIVE: Simvastatin, a cholesterol-lowering drug, also stimulates oral bone growth when applied topically, without systemic side-effects. However, the mechanisms involved in vivo are not known. We hypothesized that bone morphogenetic protein-2, nitric oxide synthase, and cyclooxygenase-2 are involved, based on prior in vitro evidence. MATERIAL AND METHODS: A rat bilateral mandible model, where 0.5 mg of simvastatin in methylcellulose gel was placed on one side and gel alone on the other, was used to quantify nitric oxide, cyclooxygenase-2 and bone morphogenetic protein-2 (via tissue extraction, enzyme activity or immunoassay), and to analyze the bone formation rate (via undecalcified histomorphometry). Cyclooxygenase-2 and nitric oxide synthase inhibitors (NS-398 and L-NAME, respectively) were administered intraperitoneally. RESULTS: Simvastatin was found to stimulate local bone morphogenetic protein-2, nitric oxide and the regional bone formation rate (p < 0.05), whereas NS-398 inhibited bone morphogenetic protein-2 and reduced the bone formation rate (p < 0.05). CONCLUSION: These data suggest an association between simvastatin-induced bone morphogenetic protein-2 and bone formation in the mandibular microenvironment, and the negative effect of cyclooxygenase-2 inhibitors on bone growth.


Assuntos
Anticolesterolemiantes/farmacologia , Proteínas Morfogenéticas Ósseas/metabolismo , Inibidores de Ciclo-Oxigenase 2/efeitos adversos , Osteogênese/efeitos dos fármacos , Sinvastatina/farmacologia , Animais , Proteínas Morfogenéticas Ósseas/efeitos dos fármacos , Ciclo-Oxigenase 2/efeitos dos fármacos , Ciclo-Oxigenase 2/metabolismo , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , NG-Nitroarginina Metil Éster/administração & dosagem , NG-Nitroarginina Metil Éster/efeitos adversos , Óxido Nítrico Sintase/análise , Óxido Nítrico Sintase/efeitos dos fármacos , Nitrobenzenos/administração & dosagem , Nitrobenzenos/efeitos adversos , Ratos , Sulfonamidas/administração & dosagem , Sulfonamidas/efeitos adversos
17.
Clin Exp Rheumatol ; 25(6): 890-5, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18173927

RESUMO

An asymptomatic thirty-eight-year-old female developed recurrent DVT at the latter end of her first pregnancy and in the puerperium. Blood tests revealed a moderately elevated ANF (1:640) with a speckled pattern, hyperglobulinemia, and antibodies to thyroid tissues. Two months postpartum, following neurological disturbances she was found to have a patent foramen ovale and had developed paradoxical emboli to the brain causing multiple arterial occlusions. However, she also had cerebral venous occlusions as well as deep venous thromboses and pulmonary emboli, indicating a generalised prothrombotic state. Abdominal ultrasound examination revealed the presence of tumour which, on surgical removal, proved to be an ovarian carcinoma. The only antiphospholipid antibodies detectable were antibodies to mitochondria Type M5 in moderately elevated titres.


Assuntos
Síndrome Antifosfolipídica/complicações , Autoanticorpos/sangue , Cistadenocarcinoma Papilar/complicações , Cistadenocarcinoma Seroso/complicações , Mitocôndrias/imunologia , Neoplasias Ovarianas/complicações , Trombose Venosa/complicações , Adulto , Feminino , Humanos , Embolia Intracraniana/complicações , Gravidez , Complicações na Gravidez , Recidiva
18.
J Dent Res ; 85(9): 809-13, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16931862

RESUMO

UNLABELLED: Mechanical fatigue-related degeneration of the temporomandibular joint (TMJ) disc may be promoted by tractional forces. This study tested the hypotheses that tractional forces following static loading of the TMJ disc: (1) increase with compressive strain at the start of movement, and (2) are velocity-dependent during movement. Sixty-four porcine discs received a 10-N static load via an acrylic indenter for 1 or 30 sec before cyclic movement. Physical data were recorded and analyzed by ANOVA. The results showed that compressive strain and tractional forces were largest for the start of movement following 30 sec of static loading (p

Assuntos
Cartilagem Articular/fisiologia , Análise do Estresse Dentário , Disco da Articulação Temporomandibular/fisiologia , Análise de Variância , Animais , Força Compressiva , Fricção , Mastigação/fisiologia , Músculos da Mastigação/fisiologia , Movimento , Contração Muscular , Suínos , Tração
19.
Fortschr Neurol Psychiatr ; 74(10): 582-90, 2006 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-16586259

RESUMO

BACKGROUND: Running amok is considered a rare but dangerous act of violence which has been investigated predominantly on a case by case basis. German-wide data on amok cases covering the decades 1980 - 1989 and 1991 - 2000 were used to perform the first epidemiological study world-wide on the stability of socio-demographic, criminological and psychiatric variables of amok behaviour. METHODS: A content analysis study on nation-wide press reports of amok cases included a total of 104 subjects who were identified by combined homicidal-suicidal acts of violence and fulfilled structured criteria originally defined according to former Malayan amok events. RESULTS: Amok cases in both decades were comparable except for the significant increase of weapon use, especially of firearms. Total prevalence showed a tendency to decline from 1 : 5.5 million to 1 : 8.5 million men per year, females were involved in rare single cases only. The male offenders showed a bimodal age distribution with a mean of 35 years. They were professionally well qualified, but had a 5 - 7fold higher risk of unemployment than the normal population. Motives and reasons for running amok were serious but not unusual, they varied widely and addressed all areas of daily life. Most offenders were characterized by abnormal personality patterns such as passive, aggressive, impulsive and paranoid and were in possession of firearms and previously convicted. Psychiatric diseases such as psychosis, paranoia, depression or personality disorders were present in more than 50 % of cases; further 20 % were intoxicated. The presence of psychiatric disorders influenced patterns of violent behaviour in individual subjects. Victims were predominantly unknown to the offenders. Close to one third of the amok runners committed suicide or were killed by legal authorities. CONCLUSION: Amok represents a temporarily stable syndrome of extreme violent behaviour even in modern industrialized societies. Subjects exhibit a complex combination of serious causative motives, social burden and psychiatric diseases which do not explain common causes of amok rather than the origin of amok behaviour in individual cases. Amok joins the wide spectrum of human homicidal-suicidal acts which show similarities in many aspects.


Assuntos
Violência/psicologia , Adulto , Intoxicação Alcoólica/psicologia , Feminino , Armas de Fogo , Alemanha , Homicídio/psicologia , Homicídio/estatística & dados numéricos , Humanos , Malásia , Masculino , Transtornos Mentais/psicologia , Personalidade , Suicídio/psicologia , Suicídio/estatística & dados numéricos , Síndrome , Desemprego , Violência/estatística & dados numéricos
20.
Poult Sci ; 85(2): 306-11, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16523631

RESUMO

A study was conducted to assess the effects of varying cage spaces on a commercial laying hen strain fed differing levels of dietary metabolizable energy (ME) for 15 wk. Four cage space allowances (342, 413, 516, and 690 cm2/hen) were combined with 3 levels of dietary ME (2,800, 2,850, and 2,900 kcal of ME/kg) in a 4 x 3 factorial arrangement. Each treatment was assigned to 6 replicate cages for a total of 72 cages in randomized complete block design. Feed intake and metabolizable energy intake were significantly (P < 0.01) greater for hens housed at 690 cm2/hen compared with those housed at 413 and 342 cm2/hen, but not those housed at 516 cm2/hen, across all dietary ME levels. Egg production and egg mass were significantly (P < 0.001) improved for hens housed at 690 cm2/ hen in contrast to other cage spaces and across all energy levels. There were no interaction effects of ME levels on laying hen performance at varying cage space except for body weight change. Hens housed at 516 cm2/ hen and fed 2,800 kcal of ME/kg exhibited the greatest weight change, which was significantly (P < 0.05) greater than those fed other levels of ME at the same cage space. Hens housed at 690 cm2/hen had significantly (P < 0.05) greater ME efficiency of egg production than hens housed at other cage spaces. Hens fed the diet with 2,900 kcal of ME/kg had significantly (P < 0.001) greater ME digestibility compared with those fed 2,800 or 2,580 kcal of ME/ kg with differences of 107 and 118 kcal of ME/kg, respectively. There were no significant effects of ME levels observed except ME digestibility, and no significant effects of cage space allowance on egg weight, hen weight, bone ash, or maintenance energy intake. It is evident that decreasing the number of birds per cage and increasing cage space allowance per hen had an overall positive effect on performance.


Assuntos
Galinhas/fisiologia , Dieta/veterinária , Ingestão de Energia , Abrigo para Animais , Oviposição , Fenômenos Fisiológicos da Nutrição Animal , Animais , Feminino , Minerais/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...