Controlled topological transitions in thin film phase separation

In this paper the evolution of a binary mixture in a thin-film geometry with a wall at the top and bottom is considered. By bringing the mixture into its miscibility gap so that no spinodal decomposition occurs in the bulk, a slight energetic bias of the walls towards each one of the constituents ensures the nucleation of thin boundary layers that grow until the constituents have moved into one of the two layers. These layers are separated by an interfacial region where the composition changes rapidly. Conditions that ensure the separation into two layers with a thin interfacial region are investigated based on a phase-field model. Using matched asymptotic expansions a corresponding sharp-interface problem for the location of the interface is established. It is then argued that this newly created two-layer system is not at its energetic minimum but destabilizes into a controlled self-replicating pattern of trapezoidal vertical stripes by minimizing the interfacial energy between the phases while conserving their area. A quantitative analysis of this mechanism is carried out via a thin-film model for the free interfaces, which is derived asymptotically from the sharp-interface model.Comment: Submitted 23/12/201

Systems Challenges for Hypersonic Vehicles

This paper examines the system challenges posed by fully reusable hypersonic cruise airplanes and access to space vehicles. Hydrocarbon and hydrogen fueled airplanes are considered with cruise speeds of Mach 5 and 10, respectively. The access to space matrix is examined. Airbreathing and rocket powered, single- and two-stage vehicles are considered. Reference vehicle architectures are presented. Major systems/subsystems challenges are described. Advanced, enhancing systems concepts as well as common system technologies are discussed

Performance characteristics of a rapid immunochromatographic assay for detection of pandemic influenza A (H1N1) virus in children

Rapid tests for diagnosis of influenza are valuable assets in the management of influenza in pediatric patients. However, test performance fluctuates with virus subtypes. We assessed the test characteristics of Influenzatop®, a rapid immunochromatographic influenza A and B test, in detecting pandemic 2009 influenza A (H1N1) in children up to 18years of age, using reverse transcriptase polymerase chain reaction (RT-PCR) as the gold standard. Three hundred and one pediatric outpatients with influenza-like illness were included into the study. Overall sensitivity of Influenzatop® was 64% (95% confidence interval (CI) 56-71%) but increased to 92% (95% CI, 80-97%) when performed between 24 and 48h after onset of symptoms. Positive Influenzatop® results among RT-PCR-positive patients were associated with higher viral load. No significant variation in test performance could be detected when analyzed by age and high versus low prevalence period. Overall test specificity was 99% (95% CI, 95-100%); positive and negative predictive values were 98% (95% CI, 93-99%) and 70% (95% CI, 63-76%), respectively. Conclusion: Influenzatop® rapid influenza test is a sound tool in the diagnosis of H1N1 in pediatric patients when employed 24-48h after onset of symptom

Performance characteristics of a rapid immunochromatographic assay for detection of pandemic influenza A (H1N1) virus in children.

UNLABELLED Rapid tests for diagnosis of influenza are valuable assets in the management of influenza in pediatric patients. However, test performance fluctuates with virus subtypes. We assessed the test characteristics of Influenzatop®, a rapid immunochromatographic influenza A and B test, in detecting pandemic 2009 influenza A (H1N1) in children up to 18 years of age, using reverse transcriptase polymerase chain reaction (RT-PCR) as the gold standard. Three hundred and one pediatric outpatients with influenza-like illness were included into the study. Overall sensitivity of Influenzatop® was 64% (95% confidence interval (CI) 56-71%) but increased to 92% (95% CI, 80-97%) when performed between 24 and 48 h after onset of symptoms. Positive Influenzatop® results among RT-PCR-positive patients were associated with higher viral load. No significant variation in test performance could be detected when analyzed by age and high versus low prevalence period. Overall test specificity was 99% (95% CI, 95-100%); positive and negative predictive values were 98% (95% CI, 93-99%) and 70% (95% CI, 63-76%), respectively. CONCLUSION Influenzatop® rapid influenza test is a sound tool in the diagnosis of H1N1 in pediatric patients when employed 24-48 h after onset of symptoms

Propagating topological transformations in thin immiscible bilayer films

A physical mechanism for the topological transformation of a two-layer system confined by two substrates is proposed. Initially the two horizontal layers, A and B, are on top of each other, but upon a sufficiently large disturbance, they can rearrange themselves through a spontaneously propagating sectioning to create a sequence of vertical alternating domains ABABAB. This generic topological transformation could be used to control the morphology of fabricated nanocomposites by first creating metastable layered structures and then triggering their transformation. The generality is underscored by formulating conditions for this topological transformation in terms of the interface energies between phases and substrates. The theoretical estimate for the width of the domains is confirmed by simulations of a phase-field model and its thin-film/sharp-interface approximation

Propagating topological transformations in thin immiscible bilayer films

A physical mechanism for the topological transformation of a two-layer system confined by two substrates is proposed. Initially the two horizontal layers, A and B, are on top of each other, but upon a sufficiently large disturbance, they can rearrange themselves through a spontaneously propagating sectioning to create a sequence of vertical alternating domains ABABAB. This generic topological transformation could be used to control the morphology of fabricated nanocomposites by first creating metastable layered structures and then triggering their transformation. The generality is underscored by formulating conditions for this topological transformation in terms of the interface energies between phases and substrates. The theoretical estimate for the width of the domains is confirmed by simulations of a phase-field model and its thin-film/sharp-interface approximation

Combination of intact, middle-up and bottom-up levels to characterize 7 therapeutic monoclonal antibodies by capillary electrophoresis – Mass spectrometry

Significant growth of biopharmaceuticals requires powerful analytical methods to better understand their structure by establishing a complete characterization. To this end, a combination of bottom-up, middle-up and intact molecule levels with a capillary electrophoresis-mass spectrometry coupling has been performed to have a comprehensive picture of monoclonal antibodies. In this study, 7 worldwide health authorities approved mAbs have been analyzed to get information about their charge heterogeneity, the identification of post translational modifications (PTMs), their location and relative quantitation. Intact mAbs isoforms have been partially separated in less than 12 minutes and enabled to have a global illustration of mAbs heterogeneity and high masses PTMs characterization notably major N-glycosylation forms. Particularly, 2X-glycosylated and 1X-glycosylated forms have been partially separated. To deepen characterize PTMs carried by the backbone structure, advanced investigations at a middle-up level have been performed. Limited IdeS proteolysis allowed to study independently Fc/2 and F(ab)’2 fragments. Following the same separation conditions, isoforms of these fragments have been separated and data interpretation allowed to disclose additional PTMs as K-clip, oxidations or deamidations. A second intermediate level has been examined by adding a reduction step to establish a more precise assessment of PTMs and isoforms from the F(ab)’2 fragment. This reduction step released the light chains from the Fd fragment to get only 25 kDa fragments to analyze. CE-ESI-MS coupling allowed to get more information particularly about low masses PTMs. The precise location and relative quantitation of each PTM has been investigated at the peptidic level induced by a tryptic digestion of the studied mAbs. The concordance of the results shows the efficiency of the CE-ESI-MS coupling to characterize mAbs and highlight the need of the multi-level combination to get a comprehensive characterization of biotherapeutics

Trust in medical organizations predicts pandemic (H1N1) 2009 vaccination behavior and perceived efficacy of protection measures in the Swiss public

Following the recent avian influenza and pandemic (H1N1) 2009 outbreaks, public trust in medical and political authorities is emerging as a new predictor of compliance with officially recommended protection measures. In a two-wave longitudinal survey of adults in French-speaking Switzerland, trust in medical organizations longitudinally predicted actual vaccination status 6months later, during the pandemic (H1N1) 2009 vaccination campaign. No other variables explained significant amounts of variance. Trust in medical organizations also predicted perceived efficacy of officially recommended protection measures (getting vaccinated, washing hands, wearing a mask, sneezing into the elbow), as did beliefs about health issues (perceived vulnerability to disease, threat perceptions). These findings show that in the case of emerging infectious diseases, actual behavior and perceived efficacy of protection measures may have different antecedents. Moreover, they suggest that public trust is a crucial determinant of vaccination behavior and underscore the practical importance of managing trust in disease prevention campaign

Developments and recent advancements in the field of endogenous amino acid selective bond forming reactions for bioconjugation.

Bioconjugation methodologies have proven to play a central enabling role in the recent development of biotherapeutics and chemical biology approaches. Recent endeavours in these fields shed light on unprecedented chemical challenges to attain bioselectivity, biocompatibility, and biostability required by modern applications. In this review the current developments in various techniques of selective bond forming reactions of proteins and peptides were highlighted. The utility of each endogenous amino acid-selective conjugation methodology in the fields of biology and protein science has been surveyed with emphasis on the most relevant among reported transformations; selectivity and practical use have been discussed.journal articleresearch support, non-u.s. gov'treview2015 Aug 072015 05 22importe

About thiol derivatization and resolution of basic proteins in two-dimensional electrophoresis.

web publisher www.interscience.wiley.comInternational audienceThe influence of thiol blocking on the resolution of basic proteins by two-dimensional electrophoresis was investigated. Cysteine blocking greatly increased resolution and decreased streaking, especially in the basic region of the gels. Two strategies for cysteine blocking were found to be efficient: classical alkylation with maleimide derivatives and mixed disulfide exchange with an excess of a low molecular weight disulfide. The effect on resolution was significant enough to allow correct resolution of basic proteins with in-gel rehydration on wide gradients (e.g. 3-10 and 4-12), but anodic cup-loading was still required for basic gradients (e.g. 6-12 or 8-12). These results demonstrate that thiol-related problems are not solely responsible for streaking of basic proteins on two-dimensional gels