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Background and Purpose: With the growing interest in total neoadjuvant treatment for locally advanced rectal adenocarcinoma (LARC) there is an urgent unmet need to identify predictive markers of response to long-course neoadjuvant concurrent chemoradiotherapy (LCRT). O6-Methylguanine (O6-MG)-DNA-methyltransferase (MGMT) gene methylation has been associated in some malignancies with response to concurrent chemoradiotherapy. We attempted to find if pathologic response to LCRT was associated with MGMT promoter hypermethylation (MGMTh). Materials and Methods: Patients were identified with LARC, available pre-treatment biopsy specimens, and at least 1 year of follow-up who received LCRT followed by surgical resection within 6 months. Biopsies were tested for MGMTh using a Qiagen pyrosequencing kit (Catalog number 970061). The primary outcome of LCRT responsiveness was based on tumor regression grade (TRG), with grades of 0-1 considered to have excellent response and grades of 2-3 considered to be non-responders. Secondary outcomes included overall survival (OS) and recurrence free survival (RFS). Results: Of 96 patients who met inclusion criteria, 76 had samples which produced reliable assay results. MGMTh corresponded with higher grade and age of the biopsy specimen. The percentage of responders to LCRT was higher amongst the MGMTh patients than the MGMTn patients (60.0% vs 27.5%, p value = 0.0061). MGMTh was not significantly associated with improved OS (2-year OS of 96.0% vs 98.0%, p = 0.8102) but there was a trend for improved RFS (2-year RFS of 87.6% vs 74.2%, p = 0.0903). Conclusion: Significantly greater tumor regression following LCRT was seen in MGMTh LARC. Methylation status may help identify good candidates for close observation without surgery following LCRT.
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INTRODUCTION: Paracetamol pharmacokinetics (PK) is highly variable in older fit adults after intravenous administration. Frailty and oral administration likely result in additional variability. The aim was to determine oral paracetamol PK and variability in geriatric inpatients. METHODS: A population PK analysis, using NONMEM 7.2, was performed on 245 paracetamol samples in 40 geriatric inpatients (median age 87 [range 80-95] years, bodyweight 66.4 [49.3-110] kg, 92.5% frail [Edmonton Frail Scale]). All subjects received paracetamol 1000 mg as tablet (72.5%) or granulate (27.5%) three times daily. Simulations of dosing regimens (1000 mg every 6 hours [q6h] or q8h) were performed to determine target attainment, using mean steady-state concentration (Css-mean) of 10 mg/L as target. RESULTS: A one-compartment model with first order absorption and lag time best described the data. The inter-individual variability was high, with absorption rate constant containing the highest variability. The inter-individual variability could not be explained by covariates. Simulations of 1000 mg q6h and q8h resulted in a Css-mean of 10.8 [25-75th percentiles 8.2-12.7] and 8.13 [6.3-9.6] mg/L, respectively, for the average geriatric inpatient. The majority of the population remained off-target (22.2% [q6h] and 52.2% [q8h] <8 mg/L; 31.3 [q6h] and 7.6% [q8h] >12 mg/L). CONCLUSION: A population of average geriatric inpatients achieved target Css-mean with paracetamol 1000 mg q6h, while q8h resulted in underexposure for the majority of them. Due to high unexplained variability, a relevant proportion remained either above or below the target concentration of 10 mg/L. Research focusing on PK, efficacy and safety is needed to recommend dosing regimens.
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Acetaminofen , Idoso Fragilizado , Idoso , Idoso de 80 Anos ou mais , Antibacterianos , Peso Corporal , Humanos , Infusões IntravenosasRESUMO
PURPOSE: Despite the rapidly expanding knowledge in the field of Geriatric Emergency Medicine in Europe, widespread implementation of change is still lacking. Many opportunities in everyday clinical care are missed to improve care for this susceptible and growing patient group. The aim was to develop expert clinical recommendations on Geriatric Emergency Medicine to be disseminated across Europe. METHODS: A group of multi-disciplinary experts in the field of Geriatric Emergency Medicine in Europe was assembled. Using a modified Delphi procedure, a prioritized list of topics related to Geriatric Emergency Medicine was created. Next, a multi-disciplinary group of nurses, geriatricians and emergency physicians performed a review of recent guidelines and literature to create recommendations. These recommendations were voted upon by a group of experts and placed on visually attractive posters. The expert group identified the following eight subject areas to develop expert recommendations on: Comprehensive Geriatric Assessment in the Emergency Department (ED), age/frailty adjusted risk stratification, delirium and cognitive impairment, medication reviews in the ED for older adults, family involvement, ED environment, silver trauma, end of life care in the acute setting. RESULTS: Eight posters with expert clinical recommendations on the most important topics in Geriatric Emergency Medicine are now available through https://posters.geriemeurope.eu/ . CONCLUSION: Expert clinical recommendations for Geriatric Emergency Medicine may help to improve care for older patients in the Emergency Department and are ready for dissemination across Europe.
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Medicina de Emergência , Fragilidade , Geriatria , Idoso , Serviço Hospitalar de Emergência , Avaliação Geriátrica , HumanosRESUMO
The objective of this study was to investigate the effects of a gel formulation from the association of Plectranthus neochilus and Cnidoscolus quercifolius on tissue repair in cutaneous wounds in rats. A surgical wound was induced in 35 Wistar rats and treated according to group: G1 - commercial phytotherapeutic gel; G2 - Carbopol gel 1%; G3, 4, 5 - gel formulation from Boldo-gambá and Favela (FGBF) at 2.5%, 5%, and 10%, respectively. 1ml of the product was applied topically daily, for 14 days. Macroscopic evaluation of the wound showed inflammation, granulation, and epithelization in all groups. The FGBF 2.5% group showed greater angiogenic potential. There was a significant difference between the surgical area of the wounds treated with FGBF 2.5%, 5%, or 10% compared to the group with the commercial phytotherapeutic gel. On histomorphometry of the skin, there were reepithelization of the epidermis and superficial dermis, longitudinal collagen fibers, fibroblasts, and blood vessels, and in the deeper dermis, fibroblasts, transverse and longitudinal collagen fibers, blood vessels, and inflammatory cells. The 2.5% formulation had the greatest increase in fibroblast proliferation and most intense collagenization on day 14 of treatment.(AU)
Este trabalho objetivou investigar os efeitos de uma formulação em gel da associação da Plectranthus neochilus e da Cnidoscolus quercifolius no processo de reparação tecidual em feridas cutâneas de ratos. Foi induzida uma ferida cirúrgica em 35 ratos Wistar, sendo tratadas de acordo com os grupos: G1 - fitoterápico comercial; G2 - gel de carbopol 1%; G3, G4 e G5 - formulação gel boldo-gambá mais favela (FGBF) 2,5%, 5% e 10%, respectivamente. Aplicou-se 1mL do produto, via tópica, diariamente, durante 14 dias. Na avaliação macroscópica das feridas, verificou-se inflamação, granulação e epitelização em todos os grupos. O grupo FGBF 2,5% apresentou maior potencial angiogênico. Houve diferença significativa entre as áreas cirúrgicas das feridas tratadas com os FGBF 2,5%, 5% ou 10%, comparados ao grupo com o gel fitoterápico comercial. Na histomorfometria da pele, observou-se reepitelização da epiderme e da derme superficial, fibras colágenas longitudinais, fibroblastos e vasos sanguíneos e, na derme profunda, fibroblastos, fibras colágenas transversais e longitudinais, vasos sanguíneos e células inflamatórias. A formulação a 2,5% teve o maior aumento na proliferação de fibroblastos e mais intensa colagenização no dia 14 de tratamento.(AU)
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Animais , Ratos , Cicatrização , Ferimentos e Lesões/terapia , Jatropha/química , Plectranthus/química , Plantas Medicinais , Ferimentos e Lesões/veterinária , Ratos Wistar/fisiologia , Fitoterapia/veterináriaAssuntos
Portador Sadio/prevenção & controle , Infecção Hospitalar/prevenção & controle , Transmissão de Doença Infecciosa/prevenção & controle , Enterococcus faecium/isolamento & purificação , Infecções por Bactérias Gram-Positivas/prevenção & controle , Isolamento de Pacientes/métodos , Enterococos Resistentes à Vancomicina/isolamento & purificação , Portador Sadio/transmissão , Infecção Hospitalar/transmissão , Infecções por Bactérias Gram-Positivas/transmissão , Humanos , Estudos Retrospectivos , Fatores de TempoRESUMO
Rhinoviruses (RVs) are frequently detected respiratory viruses that cause mild common cold symptoms, but may also lead to more severe respiratory tract infections. The large number of RV types, classified into species A, B and C, hampers clear insights into the epidemiology and clinical significance of each RV type. The aim of this study was to map the circulation of RV types in the Amsterdam area. RV-positive nasopharyngeal and oropharyngeal samples, collected from 2007 to 2012 in the Academic Medical Centre (Amsterdam, the Netherlands), were typed based on the sequence of the region coding for capsid proteins VP4 and VP2. RV-A, RV-B and RV-C were found in proportions of of 52.4% (334/637), 11.3% (72/637), and 36.2% (231/637), respectively. We detected 129 of the 167 currently classified types. RVs circulated throughout the entire year with a peak in the autumn and a decline in the summer. Some RV types were observed throughout the entire sampling period and others had a more seasonal pattern. Nine RV-A and four RV-B novel provisionally assigned types were identified. This study provides an insight into the molecular epidemiology of RVs in the Amsterdam area. The RVs circulating are diverse and include several provisionally new types.
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Proteínas do Capsídeo/genética , Resfriado Comum/epidemiologia , Rhinovirus/genética , Rhinovirus/isolamento & purificação , Resfriado Comum/virologia , Técnicas de Genotipagem , Humanos , Epidemiologia Molecular , Nasofaringe/virologia , Países Baixos/epidemiologia , RNA Viral/isolamento & purificação , Rhinovirus/classificação , Estações do Ano , Análise de Sequência de DNARESUMO
Irritable bowel syndrome (IBS) is a common functional gastro-intestinal disorder, characterized by abdominal pain and altered intestinal motility. Visceral hypersensitivity is an important hallmark feature of IBS and is believed to underlie abdominal pain in patients with IBS. The two main risk factors associated with the development of IBS are gastrointestinal inflammation and psychological distress. On a peripheral level, visceral sensitivity seems to be modulated by several mechanisms. Immune cells in the mucosal wall, such as mast cells, and enterochromaffin cells may sensitize afferent nerves by release of their mediators. Furthermore, increased mucosal permeability, altered intestinal microflora and dietary habits may contribute to this feature. On a central level, an increased prevalence of psychiatric comorbidities is demonstrated in IBS patients, alongside alterations in the hormonal brain-gut axis, increased vigilance towards intestinal stimuli and functional and structural changes in the brain. The pathogenesis of IBS is complicated and multifactorial and the treatment remains clinically challenging. Dietary measures and symptomatic control are the cornerstones for IBS treatment and may be sufficient for patients experiencing mild symptoms, alongside education, reassurance and an effective therapeutic physician-patient relationship. New pharmacological therapies are aimed at interfering with mediator release and/or blockade of the relevant receptors within the gut wall, while modulation of the intestinal flora and diet may also be of therapeutic benefit. Tricyclic anti-depressants and serotonin reuptake inhibitors act both on a central and peripheral level by modulating pain signalling pathways.
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Dor Abdominal/imunologia , Encéfalo/fisiopatologia , Hiperalgesia/imunologia , Hiperestesia/imunologia , Intestinos/imunologia , Síndrome do Intestino Irritável/imunologia , Estresse Psicológico/fisiopatologia , Dor Abdominal/fisiopatologia , Dor Abdominal/psicologia , Humanos , Hiperalgesia/fisiopatologia , Hiperalgesia/psicologia , Hiperestesia/fisiopatologia , Hiperestesia/psicologia , Intestinos/inervação , Intestinos/fisiopatologia , Síndrome do Intestino Irritável/fisiopatologia , Síndrome do Intestino Irritável/psicologia , Estresse Psicológico/psicologiaRESUMO
The selection of topics for the special issue on peace psychology (October 2013) probably gave readers the impression that peace psychology should be defined as the study of conflict and peace at intergroup, societal, and global levels.
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Conflito Psicológico , Psicologia , Guerra , Humanos , Relações InterpessoaisRESUMO
Global change factors affect plant carbon uptake in concert. In order to investigate the response directions and potential interactive effects, and to understand the underlying mechanisms, multifactor experiments are needed. The focus of this study was on the photosynthetic response to elevated CO(2) [CO2; free air CO(2) enrichment (FACE)], drought (D; water-excluding curtains), and night-time warming (T; infrared-reflective curtains) in a temperate heath. A/C(i) curves were measured, allowing analysis of light-saturated net photosynthesis (P(n)), light- and CO(2)-saturated net photosynthesis (P(max)), stomatal conductance (g(s)), the maximal rate of Rubisco carboxylation (V(cmax)), and the maximal rate of ribulose bisphosphate (RuBP) regeneration (J(max)) along with leaf δ(13)C, and carbon and nitrogen concentration on a monthly basis in the grass Deschampsia flexuosa. Seasonal drought reduced P(n) via g(s), but severe (experimental) drought decreased P(n) via a reduction in photosynthetic capacity (P(max), J(max), and V(cmax)). The effects were completely reversed by rewetting and stimulated P(n) via photosynthetic capacity stimulation. Warming increased early and late season P(n) via higher P(max) and J(max). Elevated CO(2) did not decrease g(s), but stimulated P(n) via increased C(i). The T×CO2 synergistically increased plant carbon uptake via photosynthetic capacity up-regulation in early season and by better access to water after rewetting. The effects of the combination of drought and elevated CO(2) depended on soil water availability, with additive effects when the soil water content was low and D×CO2 synergistic stimulation of P(n) after rewetting. The photosynthetic responses appeared to be highly influenced by growth pattern. The grass has opportunistic water consumption, and a biphasic growth pattern allowing for leaf dieback at low soil water availability followed by rapid re-growth of active leaves when rewetted and possibly a large resource allocation capability mediated by the rhizome. This growth characteristic allowed for the photosynthetic capacity up-regulations that mediated the T×CO2 and D×CO2 synergistic effects on photosynthesis. These are clearly advantageous characteristics when exposed to climate changes. In conclusion, after 1 year of experimentation, the limitations by low soil water availability and stimulation in early and late season by warming clearly structure and interact with the photosynthetic response to elevated CO(2) in this grassland species.
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Dióxido de Carbono/farmacologia , Secas , Ecossistema , Fotossíntese/efeitos dos fármacos , Poaceae/efeitos dos fármacos , Poaceae/fisiologia , Temperatura , Carbono/metabolismo , Isótopos de Carbono , Luz , Nitrogênio/metabolismo , Fotossíntese/efeitos da radiação , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Estômatos de Plantas/efeitos da radiação , Poaceae/efeitos da radiação , Chuva , Análise de Regressão , Estações do Ano , Solo/química , ÁguaRESUMO
The impact of elevated CO2, periodic drought and warming on photosynthesis and leaf characteristics of the evergreen dwarf shrub Calluna vulgaris in a temperate heath ecosystem was investigated. Photosynthesis was reduced by drought in midsummer and increased by elevated CO2 throughout the growing season, whereas warming only stimulated photosynthesis early in the year. At the beginning and end of the growing season, a T × CO2 interaction synergistically stimulated plant carbon uptake in the combination of warming and elevated CO2. At peak drought, the D × CO2 interaction antagonistically down-regulated photosynthesis, suggesting a limited ability of elevated CO2 to counteract the negative effect of drought. The response of photosynthesis in the full factorial combination (TDCO2) could be explained by the main effect of experimental treatments (T, D, CO2) and the two-factor interactions (D × CO2, T × CO2). The interactive responses in the experimental treatments including elevated CO2 seemed to be linked to the realized range of treatment variability, for example with negative effects following experimental drought or positive effects following the relatively higher impact of night-time warming during cold periods early and late in the year. Longer-term experiments are needed to evaluate whether photosynthetic down-regulation will dampen the stimulation of photosynthesis under prolonged exposure to elevated CO2.
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Calluna/fisiologia , Dióxido de Carbono/metabolismo , Carbono/metabolismo , Secas , Temperatura Alta , Água/metabolismo , Aclimatação , Calluna/metabolismo , Isótopos de Carbono/análise , Mudança Climática , Regulação para Baixo , Ecossistema , Luz , Nitrogênio/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Brotos de Planta/fisiologia , Estômatos de Plantas/fisiologia , Solo/químicaRESUMO
OBJECTIVES: Patients with rheumatoid arthritis (RA) and clinicians have different views about benefits from treatments. More knowledge is needed about how patients assess outcomes in order to update current measurements. METHODS: Focus group interviews were performed at four Swedish rheumatology clinics. A total of 25 patients with RA were included, representing a wide range of ages and disease duration. Predetermined topics relating to important outcomes from and satisfaction/dissatisfaction with RA treatments were discussed. RESULTS: The participants' initial outcome assessments included physical and psychosocial items, which comprised overall treatment goals such as impairment in social roles, fatigue, daily activities and self-confidence. The identified themes were 'Normal life', 'Physical capacity', 'Independence' and 'Well-being'. Satisfaction with treatment was associated with the quality of communication between staff and the patient. The participants assumed this as a prerequisite for a treatment to work. Patients wanted to be accepted as experts on their own bodies, and expected all clinicians to be experts on RA. This made it possible for patients to 'take charge' of their life situation. Good resources for and access to rheumatology care were desired. CONCLUSIONS: Suggesting a holistic approach to rheumatology care, the study results indicate that the illness and outcomes have to be evaluated within an individual RA patient's total life situation, described in the identified themes: 'Normal life', 'Physical capacity', 'Independence' and 'Well-being'. Development and validation of measurements covering these issues is suggested. More research is needed about communication and how patients experience their roles in the rheumatology clinic.
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Artrite Reumatoide/psicologia , Artrite Reumatoide/reabilitação , Satisfação do Paciente , Atividades Cotidianas , Adulto , Idoso , Artrite Reumatoide/tratamento farmacológico , Comunicação , Feminino , Grupos Focais , Acessibilidade aos Serviços de Saúde , Humanos , Controle Interno-Externo , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Relações Profissional-Paciente , Qualidade de Vida , Resultado do TratamentoRESUMO
Promotion of uptake of essential metabolites is a possible reason for the general stimulation of gonococcal metabolism which is caused by lactate (1 mM) in a defined medium containing glucose (5 mM). However, although uptake of(14)C adenine by gonococci [strain BS4(agar)] held for 4 or 7 min at 37 degrees C in Hanks balanced salt solution was increased for lactate treated gonococci compared with control organisms, uptake of(14)C glucose and(14)C proline under these conditions was unaffected. Hence, there is no evidence that lactate produces general stimulation of metabolite uptake. Unlike the other metabolites, cytidine 5'-monophospho-(14)CN-acetyl neuraminic acid (CMP-(14)CNANA), the substrate for sialylation of gonococcal lipopolysaccharide (LPS), was adsorbed in substantial quantities by gonococci held on ice for 6 min. Also, the increase in uptake of CMP-(14)CNANA at 37 degrees C over that adsorbed at 0 degrees C was much smaller (less than two-fold) than for the other compounds (4-30-fold). The substantial adsorption at 0 degrees C suggested a surface receptor for CMP-(14)CNANA. It is probably the sialyltransferase because a sialyltransferase deficient mutant, JB1, did not absorb CMP-(14)CNANA at 0 degrees C or take it up at 37 degrees C, in contrast to its parent strain, F62, which behaved similarly to strain BS4 (agar). This supports previous evidence for a surface location of the sialyltransferase. There was a small increase in adsorption of CMP-(14)CNANA in lactate treated gonococci indicating a slight increase in the surface enzyme. This could enhance LPS sialylation and hence affect pathogenicity.
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Glucose/metabolismo , Ácido Láctico/metabolismo , Neisseria gonorrhoeae/metabolismo , Sialiltransferases/metabolismo , Adenina/metabolismo , Adsorção , Meios de Cultura , Ácido N-Acetilneuramínico do Monofosfato de Citidina/metabolismo , Neisseria gonorrhoeae/enzimologia , Prolina/metabolismo , Receptores de Superfície Celular/metabolismo , TemperaturaRESUMO
PURPOSE: An important determinant of the clinical success of ceramic restorations is the bond strength of the luting agent to the seating surface and the prepared tooth structures. Manufacturers of ceramic systems frequently specify both the luting agent and preluting treatment of the seating surface of the crown. Procera AllCeram is an all-ceramic crown comprising a porcelain-veneered coping of densely sintered, high-purity aluminum oxide. This study evaluated the shear bond strength of 4 luting agents: zinc-phosphate, glass-ionomer, resin-modified glass-ionomer, and resin cement (dual cured) to Procera aluminum oxide coping material. The luting agents were subjected to different surface treatments: untreated, sandblasted, or silica coated by the Rocatec system. MATERIALS AND METHODS: Cylindric and cubic specimens of the coping material were luted together, and the shear force necessary to separate the cylinder from the cube was measured with a universal testing machine. The surfaces of the specimens were also analyzed. RESULTS: No significant differences were recorded for the shear bond strengths of the luting agents to the untreated aluminum oxide. Glass-ionomer and the resin-modified glass-ionomer cements had the highest values (4.2 +/- 2.5 MPa and 4.3 +/- 1.9 MPa, respectively), and the lowest were 3.3 +/- 2.3 MPa for the resin cement and 3.2 +/- 1.0 MPa for the zinc-phosphate cement. Similar results were recorded for the sandblasted aluminum oxide surfaces, except with the glass-ionomer, which was significantly higher (12.9 +/- 2.4 MPa). For all 4 luting agents, the highest shear bond strength values were recorded for the silica-coated specimens; the highest was for the resin cement, at 36.2 +/- 7.8 MPa. CONCLUSION: The bond strengths between resin cement and aluminum oxide specimens treated by the Rocatec system were significantly higher than those of the other materials and surface treatments evaluated.
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Óxido de Alumínio/química , Cerâmica/química , Colagem Dentária , Cimentos Dentários/química , Silanos/química , Dióxido de Silício/química , Análise de Variância , Coroas , Porcelana Dentária/química , Análise do Estresse Dentário/instrumentação , Cimentos de Ionômeros de Vidro/química , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Cimentos de Resina/química , Estresse Mecânico , Propriedades de Superfície , Cimento de Fosfato de Zinco/químicaAssuntos
Broncodilatadores/farmacologia , Neuropeptídeos/farmacologia , Vasodilatadores/farmacologia , Agonistas Adrenérgicos beta/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Broncoconstrição , Humanos , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , Músculo Liso Vascular/efeitos dos fármacos , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Artéria Pulmonar/efeitos dos fármacos , Peptídeo Intestinal Vasoativo/farmacologiaRESUMO
Highly cross-linked networks have been obtained by photoinitiated camphorquinone-amine polymerization of tris[2-(acryloyloxy)ethyl]isocyanurate alone and/or with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol triacrylate or pentaerythritol triacrylate, which can be considered a new class of dental restorative resins. The most effective coinitiators in this system are amines such as ethyl-4-dimethylaminobenzoate, N,N-dimethyl-benzylamine, and 2,4,6-tris(dimethylaminomethyl)phenol. The volume shrinkages of polymerized samples were 8%-13%. The hardness of photocured resins in the presence of an inorganic filler (aluminum/fluoro/silicate glass, Ketac-Fil was slightly less than that of a restorative composite material (Z100 MP).
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Resinas Compostas/química , Terpenos/química , Triazinas/química , Acrilatos/química , Varredura Diferencial de Calorimetria , Reagentes de Ligações Cruzadas , Dureza , Luz , Polímeros/química , Propilenoglicóis/químicaAssuntos
Pessoas com Deficiência , Prioridades em Saúde , Recursos em Saúde , Transtornos da Audição , Distúrbios da Fala , Auxiliares de Comunicação para Pessoas com Deficiência , Barreiras de Comunicação , Pessoas com Deficiência/psicologia , Pessoas com Deficiência/reabilitação , Transtornos da Audição/diagnóstico , Transtornos da Audição/psicologia , Transtornos da Audição/terapia , Humanos , Distúrbios da Fala/diagnóstico , Distúrbios da Fala/psicologia , Distúrbios da Fala/terapia , SuéciaRESUMO
RATIONALE AND OBJECTIVES: The authors developed an analytic software package for the objective and reproducible assessment of a single leg separation (SLS) in the outlet strut of Björk-Shiley convexoconcave (BSCC) prosthetic heart valves. METHODS: The radiographic cinefilm recordings of 18 phantom valves (12 intact and 6 SLS) and of 43 patient valves were acquired. After digitization of regions of interest in a cineframe, several processing steps were carried out to obtain a one-dimensional corrected and averaged density profile along the central axis of each strut leg. To characterize the degree of possible separation, two quantitative measures were introduced: the normalized pit depth (NPD) and the depth-sigma ratio (DSR). The group of 43 patient studies was divided into a learning set (25 patients) and a test set (18 patients). RESULTS: All phantom valves with an SLS were detected (sensitivity, 100%) at a specificity of 100%. The threshold values for the NPD and the DSR to decide whether a fracture was present or not were 3.6 and 2.5, respectively. On the basis of the visual interpretations of the 25 patient studies (learning set) by an expert panel, it was concluded that none of the patients had an SLS. To achieve a 100% specificity by quantitative analysis, the threshold values for the NPD and the DSR were set at 5.8 and 2.5, respectively, for the patient data. Based on these threshold values, the analysis of patient data from the test set resulted in one false-negative detection and three false-positive detections. CONCLUSIONS: An analytic software package for the detection of an SLS was developed. Phantom data showed excellent sensitivity (100%) and specificity (100%). Further research and software development is needed to increase the sensitivity and specificity for patient data.
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Próteses Valvulares Cardíacas , Intensificação de Imagem Radiográfica/métodos , Adulto , Idoso , Processamento Eletrônico de Dados , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Falha de Prótese , Sensibilidade e EspecificidadeRESUMO
STATEMENT OF PROBLEM: The mechanical weakness of implant systems is a problem in the clinical situation. PURPOSE: This study experimentally evaluated how joint design influences the strength and failure mode of dental implant systems. MATERIAL AND METHODS: The strength tests focused on the systems as a whole. Seven implant systems with different joint design were evaluated. RESULTS: Strength and failure mode varied significantly between the implant systems and deep joints, in contrast to shallow joints, favored resistance to bending moments. The mean failure force ranged between 138 to 693 Newtons for the various implant systems. CONCLUSION: In construction of implant systems, joint depth should be taken into consideration.