Influence of opacifiers on dimensional stability and detail reproduction of maxillofacial silicone elastomer

<p>Abstract</p> <p>Background</p> <p>We evaluated the influence of chemical disinfection and accelerated aging on the dimensional stability and detail reproduction of a silicone elastomer containing one of two opacifiers.</p> <p>Methods</p> <p>A total of 90 samples were fabricated from Silastic MDX 4-4210 silicone and divided into groups (n = 10) according to opacifier content (barium sulfate or titanium dioxide) and disinfectant solution (neutral soap, Efferdent, or 4% chlorhexidine). The specimens were disinfected 3 times per week during 60 days and then subjected to accelerated aging for 1008 hours. Dimensional stability and detail reproduction tests were performed after specimens' fabrication (baseline), chemical disinfection and periodically during accelerated aging (252, 504, and 1008 hours). The results were analyzed using 3-way repeated-measures ANOVA and the Tukey HSD test (α = 0.05).</p> <p>Results</p> <p>All groups exhibited dimensional changes over time. The opacifier (p = .314), period (p < .0001) and their interactions (p = .0041) affected the dimensional stability of the silicone. Statistical significant dimensional differences occurred between groups with (0.071) and without opacifiers (0.053). Accelerated aging influenced the dimensional stability of the samples. All groups scored 2 in the detail reproduction tests, which represents the fully reproducing of three test grooves with accurate angles.</p> <p>Conclusions</p> <p>Incorporation of opacifiers alters the dimensional stability of silicones used in facial prosthetics, but seems to have no influence on detail reproduction. Accelerated aging is responsible for most of the dimensional changes in Silastic MDX4 4210, but all dimensional changes measured in this study remained within the limits of stability necessary for this application.</p

Antibacterial and antibiofilm activities of quercetin against clinical isolates of Staphyloccocus aureus and Staphylococcus saprophyticus with resistance profile

The aim of this study was to determine the antibacterial and antibiofilm properties of quercetin against clinical isolates of Staphyloccocus aureus and Staphylococcus saprophyticus with resistance profile. The antibacterial activity of quercetin was performed by the determination of the minimum inhibitory concentration (MIC) through the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The percentage of inhibition of Staphylococcus spp. biofilm, after treatment with sub-inhibitory concentrations of quercetin (MIC/2 and MIC/4), was evaluated by the violet crystal assay. Quercetin showed an antimicrobial activity against clinical isolates of methicillin-susceptible S. aureus (MSSA) (MIC = 250 µg/ml), methicillin-resistant S. aureus (MRSA) (MIC = 500 µg/ml), vancomycin-intermediate S. aureus (VISA) (MIC = 125 and 150 µg/ml), S. saprophyticus resistant to oxacillin (MIC = 62.5 to 125 µg/ml), vancomycin-resistant S. aureus (VRSA) and S. saprophyticus resistant to oxacillin and vancomycin (MIC = 500 to 1000 µg/ml). At MIC/2 and MIC/4 the quercetin inhibit 46.5 ± 2.7% and 39.4 ± 4.3% of the S. aureus biofilm, respectively, and 51.7 ± 5.5% and 46.9 ± 5.5% of the S. saprophyticus biofilm, respectively. According to the results of this study, it was noticed that the quercetin presented an antibacterial activity against strains of Staphylococcus spp. with resistance profile and also inhibited the bacterial biofilm production even in sub-inhibitory concentrations

Size- And temperature-dependent magnetization of iron nanoclusters

The magnetic behavior of bcc iron nanoclusters, with diameters between 2 and 8 nm, is investigated by means of spin dynamics simulations coupled to molecular dynamics, using a distance-dependent exchange interaction. Finite-size effects in the total magnetization as well as the influence of the free surface and the surface/core proportion of the nanoclusters are analyzed in detail for a wide temperature range, going beyond the cluster and bulk Curie temperatures. Comparison is made with experimental data and with theoretical models based on the mean-field Ising model adapted to small clusters, and taking into account the influence of low coordinated spins at free surfaces. Our results for the temperature dependence of the average magnetization per atom MT, including the thermalization of the transnational lattice degrees of freedom, are in very good agreement with available experimental measurements on small Fe nanoclusters. In contrast, significant discrepancies with experiment are observed if the translational degrees of freedom are artificially frozen. The finite-size effects on MT are found to be particularly important near the cluster Curie temperature. Simulated magnetization above the Curie temperature scales with cluster size as predicted by models assuming short-range magnetic ordering. Analytical approximations to the magnetization as a function of temperature and size are proposed.Fil: Dos Santos Mendez, Gonzalo Joaquín. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Aparicio, Romina Marcela. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Linares, D.. Universidad Nacional de San Luis. Facultad de Ciencias Físico- Matemáticas y Naturales; ArgentinaFil: Miranda, Enrique Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Tranchida, J.. Sandia National Laboratory; Estados UnidosFil: Pastor, G. M.. University Of Kasel; AlemaniaFil: Bringa, Eduardo Marcial. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Mayor; Chil

Evaluación de la fertilización fosfórica foliar y edáfica sobre el rendimiento de la variedad de papa ‘diacol capiro’ (solanum tuberosum l.)

En cuatro localidades se evaluó el efecto de la fertilización fosfórica edáfica y foliar sobre el rendimiento y la gravedad específica en la variedad de papa ‘Diacol Capiro’. La evaluación comprendió 20 tratamientos correspondientes a la combinación de dos factores: P edáfico (0, 100, 200, 300 y 400 kg· ha-1 de P2O5) y P foliar (0, 5, 10 y 15 kg· ha-1 de P2O5), junto con un tratamiento testigo de fertilización comercial. No se encontraron diferencias para la variable gravedad específica en ninguno de los tratamientos evaluados, por lo que se deduce que la variación en los niveles de P no afecta esta variable. En el rendimiento de tubérculo se encontraron diferencias para el factor P edáfico, mientras que no hubo diferencias para el factor P foliar. Dentro del  factor P edáfico, en la categoría primera, segunda y rendimiento total de tubérculo se observó que la variedad ‘Diacol Capiro’ presentó respuesta positiva sólo hasta la dosis de 200 kg· ha-1 de P2O5

Extraction and purification of violacein from Yarrowia lipolytica cells using aqueous solutions of surfactants

BACKGROUND: L-Asparaginase (ASNase) is an important biopharmaceutical for the treatment of acute lymphoblastic leukemia (ALL); however, with some restrictions due to its high manufacturing costs. Aqueous biphasic systems (ABS) have been suggested as more economical platforms for the separation/purification of proteins, but a full understanding of the mechanisms behind the ASNase partition is still a major challenge. Polymer/salt-based ABS with different driving-forces (salting-out and hydrophilicity/hydrophobicity effects) were herein applied to control the partition of commercial ASNase. RESULTS: The main results showed the ASNase partition to the salt- or polymer-rich phase depending on the ABS studied, with extraction efficiencies higher than 95%. For systems composed of inorganic salts, the ASNase partition was controlled by the polyethylene glycol (PEG) molecular weight used. Cholinium-salts-based ABS were able to promote a preferential ASNase partition to the polymer-rich phase using PEG-600 and to the salt-rich phase using a more hydrophobic polypropylene glycol (PPG)-400 polymer. It was possible to select the ABS composed of PEG-2000 + potassium phosphate buffer as the most efficient to separate the ASNase from the main contaminant proteins (purification factor = 2.4 ± 0.2), while it was able to maintain the enzyme activity for posterior application as part of a therapeutic. CONCLUSION: Polymer/salt ABS can be used to control the partition of ASNase and adjust its purification yields, demonstrating the ABS potential as more economic platform for the selective recovery of therapeutic enzymes from complex broths.publishe

Free 2-propen-1-amine derivative and inclusion complexes with beta-cyclodextrin: scanning electron microscopy, dissolution, cytotoxicity and antimycobacterial activity

Inclusion complexes and physical mixtures of isomeric mixture of E/Z (50:50) of 3-(4'-bromo-[1,1'-biphenyl]-4-yl)-3-(4-bromophenyl)-N,N-dimethyl-2-propen-1-amine (BBAP) and beta-cyclodextrin (beta-CD) in the molar proportion of 1:1 and 1:2 were analyzed by scanning electron microscopy. The dissolution behavior of BBAP and of the inclusion complexes were also evaluated for six hours. By scanning electron microscopy (SEM), it was possible to observe an inclusion complex formed between BBAP and beta-CD by co-evaporation, either in the molar proportion of 1:1 or 1:2. In the physical mixtures, no complex was observed as previously detected by physicochemical analysis. The dissolution studies showed that the inclusion complexes BBAP/beta-CD 1:1 and 1:2 released respectively 49.07 &plusmn; 1.48 and 40.26 &plusmn; 3.90% of BBAP during six hours. Free BBAP was less soluble than the inclusion complex and reached 9.00 &plusmn; 0.75% of dissolution. Biological assays, such as cytotoxicity to J774 macrophages and to a permanent lung fibroblast cell line (V79), indicated that the BBAP does not exhibit any additional toxic effect with the beta-CD complexes. However, the complexes were less cytotoxic to V79 cells than the free form. The BBAP/beta-CD inclusion complexes were more effective (MIC) than the free compound on several mycobacteria strains. Similar behavior was observed for BBAP/beta-CD complexes and rifampicin, a front-line antitubercular drug, on M. tuberculosis H37Rv growing inside J774 macrophages.Complexos de inclusões e misturas físicas contendo mistura isomérica E/Z (50:50) de 3-(4'-bromo-[1,1'-bifenil]-4-il)-3-(4-bromofenil)-N,N-dimetil-2-propen-1-amina (BBAP) e beta-ciclodextrina (b-CD) nas proporções molares de 1:1 e 1:2 foram analisados por microscopia eletrônica de varredura (SEM). O perfil de dissolução do BBAP e dos complexos de inclusões foram também avaliados durante 6 horas. Por microscopia eletrônica de varredura foi possível observar os complexos de inclusões formados entre BBAP e beta-CD por co-evaporação nas proporções molares de 1:1 e 1:2. Como previamente detectado pela caracterização físico-química, na mistura física não se observou a presença de complexo de inclusão. Os estudos de dissolução mostraram que os complexos de inclusões 1:1 e 1:2 liberaram, respectivamente 49.07 &plusmn; 1.48 e 40.26 &plusmn; 3.90% de BBAP durante 6 horas. BBAP na forma livre foi menos solúvel que os complexos de inclusões e atingiu 9.00 &plusmn; 0.75% de dissolução. Os ensaios de citotoxicidade em macrófagos J774 e em uma linhagem de células fibroblásticas de pulmão (V79) indicaram que o BBAP não exibiu efeito tóxico adicional quando complexado com beta-CD. Entretanto, os complexos de inclusões foram menos tóxicos para células V79 que BBAP na forma livre. Os complexos de inclusões BBAP/beta-CD foram mais efetivos (CIM) que o composto livre em várias cepas de micobactérias. Resultados semelhantes foram observados sobre M. tuberculosis H37Rv intracelular para os complexos de inclusões BBAP/b-CD e rifampicina, uma droga anti-tuberculose de primeira linha.682689Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Ictiose Arlequim: Caso Clínico

Harlequin ichthyosis is a rare autosomal recessive congenital disease in which neonates present generalized hyperkeratotic plaques and deep fissures, ectropion, eclabium, malformation of the auricular pavilion and typical facies. Although several complications related to the skin restriction may occur, support in intensive care and early introduction of systemic retinoids, such as acitretin, have significantly contributed to patients' survival and improved prognosis. The purpose of this report is to present a rare case of harlequin ichthyosis and to discuss strategies for early diagnosis and first supportive care.Ictiose arlequim é uma doença congênita autossómica recessiva rara, na qual os recém-nascidos apresentam placas de hiperqueratose generalizadas e fissuras profundas, ectrópio, eclábio, malformação do pavilhão auricular e fácies típicas. Embora várias complicações relacionadas à restrição cutânea possam ocorrer, o suporte em terapia intensiva e a introdução precoce de retinóides sistémicos, como a acitretina, têm contribuído significativamente para a melhoria da sobrevida e do prognóstico dos doentes. O objetivo deste relato é apresentar um raro caso de ictiose arlequim e discutir estratégias para o diagnóstico precoce e o primeiro tratamento de suporte

Evidence for a contribution of the APOE (but not the ACE) gene to the sleep profile of non-demented elderly adults

This study aims to investigate alleles of the human apolipoprotein E (APOE) and of the angiotensin-converting enzyme (ACE) genes as risk factors for poor quality of sleep in elderly individuals with no major cognitive decline. This cross-sectional, analytical study was conducted with 163 participants aged 75 years in average and 85% female. Sociodemographic, anthropometric and clinical data were gathered, and sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth scale, with patient followed for years prior to these evaluations to rule out onset of major mental disorders. Genotyping of classic polymorphic sites for the ApoE (rs429358 and rs7412) and the ACE (rs4646994) genes used peripheral DNA. A total of 63% of the subjects reported poor quality of sleep assessed by the PSQI whereas 54 (33%) reported daytime sleepiness through the Epworth scale. A significant correlation was observed between APOE and PSQI, with a greater frequency of the poor nighttime sleep quality phenotype among ε2 carriers, whereas no correlation was found among any of the sleep scores and the ACE genotypes. Thus, we suggest a correlation between APOE alleles and scale-assessed sleep quality scores in older adults, with no implications for ACE alleles, in a context devoid of cognitive impairment