Direct Observation of the Dynamics of Latex Particles Confined inside Thinning Water-Air Films

The dynamics of micrometer-size polystyrene latex particles confined in thinning foam films was investigated by microscopic interferometric observation. The behavior of the entrapped particles depends on the mobility of the film surfaces, the particle concentration, hydrophobicity, and rate of film formation. When the films were stabilized by sodium dodecyl sulfate, no entrapment of particles between the surfaces was possible. When protein was used as a stabilizer, a limited number of particles were caught inside the film area due to the decreased mobility of the interfaces. In this case, extraordinary long-ranged (>100 Ìm) capillary attraction leads to two-dimensional (2D) particle aggregation. A major change occurs when the microspheres are partially hydrophobized by the presence of cationic surfactant. After the foam films are opened and closed a few times, a layer of particles simultaneously adsorbed to the two interfaces is formed, which sterically inhibits any further film opening and thinning. The particles within this layer show an excellent 2D hexagonal ordering. The experimental data are relevant to the dynamics of defects in coating films, Pickering emulsions, and particle assembly into 2D arrays

A boosting method for maximizing the partial area under the ROC curve

<p>Abstract</p> <p>Background</p> <p>The receiver operating characteristic (ROC) curve is a fundamental tool to assess the discriminant performance for not only a single marker but also a score function combining multiple markers. The area under the ROC curve (AUC) for a score function measures the intrinsic ability for the score function to discriminate between the controls and cases. Recently, the partial AUC (pAUC) has been paid more attention than the AUC, because a suitable range of the false positive rate can be focused according to various clinical situations. However, existing pAUC-based methods only handle a few markers and do not take nonlinear combination of markers into consideration.</p> <p>Results</p> <p>We have developed a new statistical method that focuses on the pAUC based on a boosting technique. The markers are combined componentially for maximizing the pAUC in the boosting algorithm using natural cubic splines or decision stumps (single-level decision trees), according to the values of markers (continuous or discrete). We show that the resulting score plots are useful for understanding how each marker is associated with the outcome variable. We compare the performance of the proposed boosting method with those of other existing methods, and demonstrate the utility using real data sets. As a result, we have much better discrimination performances in the sense of the pAUC in both simulation studies and real data analysis.</p> <p>Conclusions</p> <p>The proposed method addresses how to combine the markers after a pAUC-based filtering procedure in high dimensional setting. Hence, it provides a consistent way of analyzing data based on the pAUC from maker selection to marker combination for discrimination problems. The method can capture not only linear but also nonlinear association between the outcome variable and the markers, about which the nonlinearity is known to be necessary in general for the maximization of the pAUC. The method also puts importance on the accuracy of classification performance as well as interpretability of the association, by offering simple and smooth resultant score plots for each marker.</p

Queimaduras autoinfligidas: tentativa de suicídio

OBJETIVO: Analisar a incidência, características, conduta e taxa de mortalidade de pacientes com autolesão por queimaduras internados no Centro de Queimaduras de Brasília, Distrito Federal, Brasil. MÉTODOS: Os pacientes do estudo consistiram das vítimas de queimaduras consecutivamente internadas na Unidade de Queimados do Hospital Regional da Asa Norte, Brasília, Distrito Federal, Brasil, durante o período de fevereiro de 2008 e fevereiro de 2009. Os dados foram obtidos na admissão e foram registrados prospectivamente durante a internação. Os pacientes foram seguidos até a alta ou o óbito. RESULTADOS: No período do estudo, foram admitidos 15 casos de autolesão por queimaduras na Unidade de Queimados. A média de idade foi 38,0 ± 20,6 anos; 66,7% dos casos de autolesão por queimadura eram mulheres. Na maioria dos casos eram casadas, provedoras do lar, e pobres. O maior motivo foi conflito conjugal. A taxa de mortalidade foi 40%. A área média de superfície corporal queimada foi 38,7 ± 26,1%. O álcool foi usado por 66,7% dos pacientes como causa das queimaduras. A média de duração do tratamento foi 20,1 ± 14,8 dias. Pacientes com autoinjúria por queimadura apresentaram lesões mais extensas, permaneceram mais tempo no hospital e pior prognóstico. CONCLUSÃO: Pacientes com autolesão por queimaduras apresentaram média de idade mais elevada, maior superfície corporal queimada, maior período de internação, mais complicações infecciosas e maior taxa de letalidade do que os pacientes com queimaduras acidentais. Esses pacientes precisam de constante suporte psiquiátrico, o qual pode ser útil na prevenção de futuros episódios de autoagressão

Wound Microbiology and Associated Approaches to Wound Management

The majority of dermal wounds are colonized with aerobic and anaerobic microorganisms that originate predominantly from mucosal surfaces such as those of the oral cavity and gut. The role and significance of microorganisms in wound healing has been debated for many years. While some experts consider the microbial density to be critical in predicting wound healing and infection, others consider the types of microorganisms to be of greater importance. However, these and other factors such as microbial synergy, the host immune response, and the quality of tissue must be considered collectively in assessing the probability of infection. Debate also exists regarding the value of wound sampling, the types of wounds that should be sampled, and the sampling technique required to generate the most meaningful data. In the laboratory, consideration must be given to the relevance of culturing polymicrobial specimens, the value in identifying one or more microorganisms, and the microorganisms that should be assayed for antibiotic susceptibility. Although appropriate systemic antibiotics are essential for the treatment of deteriorating, clinically infected wounds, debate exists regarding the relevance and use of antibiotics (systemic or topical) and antiseptics (topical) in the treatment of nonhealing wounds that have no clinical signs of infection. In providing a detailed analysis of wound microbiology, together with current opinion and controversies regarding wound assessment and treatment, this review has attempted to capture and address microbiological aspects that are critical to the successful management of microorganisms in wounds