5,655 research outputs found

    Self-assembly of Microcapsules via Colloidal Bond Hybridization and Anisotropy

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    Particles with directional interactions are promising building blocks for new functional materials and may serve as models for biological structures. Mutually attractive nanoparticles that are deformable due to flexible surface groups, for example, may spontaneously order themselves into strings, sheets and large vesicles. Furthermore, anisotropic colloids with attractive patches can self-assemble into open lattices and colloidal equivalents of molecules and micelles. However, model systems that combine mutual attraction, anisotropy, and deformability have---to the best of our knowledge---not been realized. Here, we synthesize colloidal particles that combine these three characteristics and obtain self-assembled microcapsules. We propose that mutual attraction and deformability induce directional interactions via colloidal bond hybridization. Our particles contain both mutually attractive and repulsive surface groups that are flexible. Analogous to the simplest chemical bond, where two isotropic orbitals hybridize into the molecular orbital of H2, these flexible groups redistribute upon binding. Via colloidal bond hybridization, isotropic spheres self-assemble into planar monolayers, while anisotropic snowman-like particles self-assemble into hollow monolayer microcapsules. A modest change of the building blocks thus results in a significant leap in the complexity of the self-assembled structures. In other words, these relatively simple building blocks self-assemble into dramatically more complex structures than similar particles that are isotropic or non-deformable

    MMS observations of electron-scale filamentary currents in the reconnection exhaust and near the X line

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    © 2016. American Geophysical Union. All Rights Reserved.We report Magnetospheric Multiscale observations of macroscopic and electron-scale current layers in asymmetric reconnection. By intercomparing plasma, magnetic, and electric field data at multiple crossings of a reconnecting magnetopause on 22 October 2015, when the average interspacecraft separation was ~10km, we demonstrate that the ion and electron moments are sufficiently accurate to provide reliable current density measurements at 30ms cadence. These measurements, which resolve current layers narrower than the interspacecraft separation, reveal electron-scale filamentary Hall currents and electron vorticity within the reconnection exhaust far downstream of the X line and even in the magnetosheath. Slightly downstream of the X line, intense (up to 3μA/m2) electron currents, a super-Alfvénic outflowing electron jet, and nongyrotropic crescent shape electron distributions were observed deep inside the ion-scale magnetopause current sheet and embedded in the ion diffusion region. These characteristics are similar to those attributed to the electron dissipation/diffusion region around the X line

    Characteristics and outcome of patients with newly diagnosed advanced or metastatic lung cancer admitted to intensive care units (ICUs)

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    BACKGROUND: Although patients with advanced or metastatic lung cancer have poor prognosis, admission to the ICU for management of life-threatening complications has increased over the years. Patients with newly diagnosed lung cancer appear as good candidates for ICU admission, but more robust information to assist decisions is lacking. The aim of our study was to evaluate the prognosis of newly diagnosed unresectable lung cancer patients. METHODS: A retrospective multicentric study analyzed the outcome of patients admitted to the ICU with a newly diagnosed lung cancer (diagnosis within the month) between 2010 and 2013. RESULTS: Out of the 100 patients, 30 had small cell lung cancer (SCLC) and 70 had non-small cell lung cancer. (Thirty patients had already been treated with oncologic treatments.) Mechanical ventilation (MV) was performed for 81 patients. Seventeen patients received emergency chemotherapy during their ICU stay. ICU, hospital, 3- and 6-month mortality were, respectively, 47, 60, 67 and 71%. Hospital mortality was 60% when invasive MV was used alone, 71% when MV and vasopressors were needed and 83% when MV, vasopressors and hemodialysis were required. In multivariate analysis, hospital mortality was associated with metastatic disease (OR 4.22 [1.4-12.4]; p = 0.008), need for invasive MV (OR 4.20 [1.11-16.2]; p = 0.030), while chemotherapy in ICU was associated with survival (OR 0.23, [0.07-0.81]; p = 0.020). CONCLUSION: This study shows that ICU management can be appropriate for selected newly diagnosed patients with advanced lung cancer, and chemotherapy might improve outcome for patients with SCLC admitted for cancer-related complications. Nevertheless, tumors' characteristics, numbers and types of organ dysfunction should be taken into account in the decisional process before admitting these patients in ICU.Peer reviewe

    Protective Effect of Ginseng Polysaccharides on Influenza Viral Infection

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    Ginseng polysaccharide has been known to have multiple immunomodulatory effects. In this study, we investigated whether Panax ginseng polysaccharide (GP) would have a preventive effect on influenza infection. Administration of mice with GP prior to infection was found to confer a survival benefit against infection with H1N1 (A/PR/8/34) and H3N2 (A/Philippines/82) influenza viruses. Mice infected with the 2009 H1N1 virus suspended in GP solution showed moderately enhanced survival rates and lower levels of lung viral titers and the inflammatory cytokine (IL-6). Daily treatment of vaccinated mice with GP improved their survival against heterosubtypic lethal challenge. This study demonstrates the first evidence that GP can be used as a remedy against influenza viral infection

    Variational Methods for Biomolecular Modeling

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    Structure, function and dynamics of many biomolecular systems can be characterized by the energetic variational principle and the corresponding systems of partial differential equations (PDEs). This principle allows us to focus on the identification of essential energetic components, the optimal parametrization of energies, and the efficient computational implementation of energy variation or minimization. Given the fact that complex biomolecular systems are structurally non-uniform and their interactions occur through contact interfaces, their free energies are associated with various interfaces as well, such as solute-solvent interface, molecular binding interface, lipid domain interface, and membrane surfaces. This fact motivates the inclusion of interface geometry, particular its curvatures, to the parametrization of free energies. Applications of such interface geometry based energetic variational principles are illustrated through three concrete topics: the multiscale modeling of biomolecular electrostatics and solvation that includes the curvature energy of the molecular surface, the formation of microdomains on lipid membrane due to the geometric and molecular mechanics at the lipid interface, and the mean curvature driven protein localization on membrane surfaces. By further implicitly representing the interface using a phase field function over the entire domain, one can simulate the dynamics of the interface and the corresponding energy variation by evolving the phase field function, achieving significant reduction of the number of degrees of freedom and computational complexity. Strategies for improving the efficiency of computational implementations and for extending applications to coarse-graining or multiscale molecular simulations are outlined.Comment: 36 page

    Analogue peptides for the immunotherapy of human acute myeloid leukemia

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    Accepted manuscript. The final publication is available at: http://link.springer.com/article/10.1007%2Fs00262-015-1762-9The use of peptide vaccines, enhanced by adjuvants, has shown some efficacy in clinical trials. However, responses are often short-lived and rarely induce notable memory responses. The reason is that self-antigens have already been presented to the immune system as the tumor develops, leading to tolerance or some degree of host tumor cell destruction. To try to break tolerance against self-antigens, one of the methods employed has been to modify peptides at the anchor residues to enhance their ability to bind major histocompatibility complex molecules, extending their exposure to the T-cell receptor. These modified or analogue peptides have been investigated as stimulators of the immune system in patients with different cancers with variable but sometimes notable success. In this review we describe the background and recent developments in the use of analogue peptides for the immunotherapy of acute myeloid leukemia describing knowledge useful for the application of analogue peptide treatments for other malignancies

    Determinants of formation of aflatoxin-albumin adducts: a seven-township study in Taiwan

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    Dietary exposure to aflatoxins is one of the major risk factors for hepatocellular carcinoma. Individual susceptibility to aflatoxin-induced hepatocarcinogenesis may be modulated by both genetic and environmental factors affecting metabolism. A cross-sectional study was performed to evaluate determinants of the formation of aflatoxin covalently bound to albumin (AFB1-albumin adducts). A total of 474 subjects who were free of liver cancer and cirrhosis and were initially selected as controls for previous case–control studies of aflatoxin-induced hepatocarcinogenesis in Taiwan, were employed in this study. Aflatoxin-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen and antibodies to hepatitis C virus by enzyme immunoassay, as well as genotypes of glutathione S-transferase M1-1 and T1-1 by polymerase chain reaction. The detection rate of AFB1-albumin adducts was significantly higher in males (42.5%) than in females (21.6%) (multivariate-adjusted odds ratio=2.6, 95% confidence interval=1.4–5.0). The formation of detectable albumin adducts was moderately higher in hepatitis B surface antigen carriers (42.8%) than in non-carriers (36.6%) (multivariate-adjusted odds ratio=1.4, 95% confidence interval=1.0–2.1). In addition, the detection rate of AFB1-albumin adducts tended to increase with the increasing number of null genotypes of glutathione S-transferase M1-1 and glutathione S-transferase T1-1. In conclusion, this cross-sectional study has assessed the relative contributions of environmental exposure and host susceptibility factors in the formation of AFB1-albumin adducts in a well characterised Chinese adult population. This study further emphasises the necessity to reduce aflatoxin exposure in people living in an area endemic for chronic hepatitis B virus infection

    Fabrication and photoluminescent properties of Tb3+ doped carbon nanodots

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    Abstract Carbon nanodots (CNDs) doped with Tb ions were synthesized using different synthetic routes: hydrothermal treatment of a solution containing carbon source (sodium dextran sulfate) and TbCl3; mixing of CNDs and TbCl3 solutions; freezing-induced loading of Tb and carbon-containing source into pores of CaCO3 microparticles followed by hydrothermal treatment. Binding of Tb ions to CNDs (Tb-CND coupling) was confirmed using size-exclusion chromatography and manifested itself through a decrease of the Tb photoluminescence lifetime signal. The shortest Tb photoluminescence lifetime was observed for samples obtained by hydrothermal synthesis of CaCO3 microparticles where Tb and carbon source were loaded into pores via the freezing-induced process. The same system displays an increase of Tb photoluminescence via energy transfer with excitation at 320–340 nm. Based on the obtained results, freezing-induced loading of cations into CNDs using porous CaCO3 microparticles as reactors is proposed to be a versatile route for the introduction of active components into CNDs. The obtained CNDs with long-lived emission may be used for time-resolved imaging and visualization in living biological samples where time-resolved and long-lived luminescence microscopy is required

    Peptide-MHC Cellular Microarray with Innovative Data Analysis System for Simultaneously Detecting Multiple CD4 T-Cell Responses

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    Peptide:MHC cellular microarrays have been proposed to simultaneously characterize multiple Ag-specific populations of T cells. The practice of studying immune responses to complicated pathogens with this tool demands extensive knowledge of T cell epitopes and the availability of peptide:MHC complexes for array fabrication as well as a specialized data analysis approach for result interpretation. T cell cultures. A novel statistical methodology was also developed to facilitate batch processing of raw array-like data into standardized endpoint scores, which linearly correlated with total Ag-specific T cell inputs. Applying these methods to analyze Influenza A viral antigen-specific T cell responses, we not only revealed the most prominent viral epitopes, but also demonstrated the heterogeneity of anti-viral cellular responses in healthy individuals. Applying these methods to examine the insulin producing beta-cell autoantigen specific T cell responses, we observed little difference between autoimmune diabetic patients and healthy individuals, suggesting a more subtle association between diabetes status and peripheral autoreactive T cells.The data analysis system is reliable for T cell specificity and functional testing. Peptide:MHC cellular microarrays can be used to obtain multi-parametric results using limited blood samples in a variety of translational settings
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