Cross-TCR Antagonism Revealed by Optogenetically Tuning the Half-Life of the TCR Ligand Binding

Activation of T cells by agonistic peptide-MHC can be inhibited by antagonistic ones. However, the exact mechanism remains elusive. We used Jurkat cells expressing two different TCRs and tested whether stimulation of the endogenous TCR by agonistic anti-Vβ8 antibodies can be modulated by ligand-binding to the second, optogenetic TCR. The latter TCR uses phytochrome B tetramers (PhyBt) as ligand, the binding half-life of which can be altered by light. We show that this half-life determined whether the PhyBt acted as a second agonist (long half-life), an antagonist (short half-life) or did not have any influence (very short half-life) on calcium influx. A mathematical model of this cross-antagonism shows that a mechanism based on an inhibitory signal generated by early recruitment of a phosphatase and an activating signal by later recruitment of a kinase explains the data.     

CaO–MgO–SiO2–P2O5- based multiphase bio-ceramics fabricated by directional solidification: Microstructure features and in vitro bioactivity studies

In vitro activity is important when considering the choice of a multiphasic bioceramic scaffold as phases can dissolve or transform at different rates. The aim of this study is focused on the synthesis and in vitro analysis of multiphasic ceramics obtained from the melt by directional solidification. Depending on the growth rate of the new composition different bioactive phases coexist in the same sample: akermanite, monticellite, tricalcium phosphate and Nurse's A phase, all of them with potential in the medical area as implant for bone or dental repair. With the knowledge of what and how phases dissolve first, it was possible to design materials to get porous scaffolds or more stable ceramics.     

Polymer Brushes on Hexagonal Boron Nitride

Direct covalent functionalization of large‐area single‐layer hexagonal boron nitride (hBN) with various polymer brushes under mild conditions is presented. The photopolymerization of vinyl monomers results in the formation of thick and homogeneous (micropatterned, gradient) polymer brushes covalently bound to hBN. The brush layer mechanically and chemically stabilizes the material and allows facile handling as well as long‐term use in water splitting hydrogen evolution reactions.     

Polymerization of methacrylate resins photoinitiated by camphorquinone and bulky amine-functionalized silsesquioxanes

Polyhedral oligomeric silsesquioxanes (SSQO) functionalized with bulky amino groups were prepared by a two-stage synthesis procedure. In a first stage, a modified organotrimethoxysilane was synthesized by reacting 1 mol of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane with 3 mol of 1,2-epoxy-3-phenoxypropane. The second stage consisted of the hydrolytic condensation of the modified silane catalyzed by formic acid. Methacrylate resins were activated for visible light polymerization by the addition of camphorquinone (CQ) in combination with different mass fractions of SSQO. The progress of monomer conversion versus irradiation time showed that the CQ/SSQO pair is an efficient photoinitiator system because a fast reaction and high conversion results from 60 s irradiation at 600 mW/cm². The SSQO were incorporated up to 22 wt% in the methacrylate resin without compromising the flexural or the compressive properties of the final material.     

Merging local patterns using an evolutionary approach

This paper describes a Decentralized Agent-based model for Theory Synthesis (DATS) implemented by MASETS, a Multi-Agent System for Evolutionary Theory Synthesis. The main contributions are the following: first, a method for the synthesis of a global theory from distributed local theories. Second, a conflict resolution mechanism, based on genetic algorithms, that deals with collision/contradictions in the knowledge discovered by different agents at their corresponding locations. Third, a system-level classification procedure that improves the results obtained from both: the monolithic classifier and the best local classifier. And fourth, a method for mining very large datasets that allows for divide-and-conquer mining followed by merging of discoveries. The model is validated with an experimental application run on 15 datasets. Results show that the global theory outperforms all the local theories, and the monolithic theory (obtained from mining the concatenation of all the available distributed data), in a statistically significant way.     

Global Assessment of Seawater Intrusion Problems (Status and Vulnerability)

In this research paper we propose a novel method to perform an integrated analysis of the status and vulnerability of coastal aquifers to seawater intrusion (SWI). The method is based on a conceptual approach of intrusion that allows to summarised results in a visual way at different spatial scales, moving from steady pictures (corresponding to instantaneous or mean values in a period) including maps and 2D conceptual cross-sections and temporal series of lumped indices. Our aim is to help in the identification of coastal groundwater bodies at risk of not achieving good chemical status according to the Water Framework Directive. The indices are obtained from available information about aquifer geometry and historical monitoring data (chloride concentration and hydraulic head data). This method may be applied even in cases where a reduced number of data are available. It does not require complex modelling and has been implemented in a GIS tool that encourages its use in other cases. Analysis of the evolution of historical time series of these indices can be used to assess resilience and trends with respect to SWI problems. This method can be also useful to compare intrusion problems in different aquifers and temporal periods.     

Graphite materials prepared by HTT of unburned carbon from coal combustion fly ashes: Performance as anodes in lithium-ion batteries

The behaviour as the potential negative electrode in lithium-ion batteries of graphite-like materials that were prepared by high temperature treatment of unburned carbon concentrates from coal combustion fly ashes was investigated by galvanostatic cycling. Emphasis was placed on the relation between the structural/morphological and electrochemical characteristics of the materials. In addition, since good electrode capacity retention on cycling is an important requirement for the manufacturing of the lithium-ion batteries, the reversible capacity provided by the materials prepared on prolonged cycling (50 cycles) was studied and the results were compared with those of petroleum-based graphite which is commercialized as anodic material for lithium-ion batteries. The graphite-like materials prepared lead to battery reversible capacities up to ∼310 mA hg⁻¹ after 50 cycles, these values were similar to those of the reference graphite. Moreover, they showed a remarkable stable capacity along cycling and low irreversible capacity. Apparently, both the high degree of crystallinity and the irregular particle shape with no flakes appear to contribute to the good anodic performance in lithium-ion batteries of these materials, thus making feasible their utilization to this end.     

驱动压电PVDF换能器的高频高电压放大器

压电换能器用于NDE（非破坏性评估）应用。PVDF（聚偏氟乙烯）换能器有很多优点．包括大带宽和高灵敏度。这些换能器需要高电压和大带宽的放大器。图1中的电路源于往期的一个设计实例（参考文献1）。电路的工作原理基本相同,但本设计可以在高至500kHz频率下驱动一个2．3nF的容性负载。