Characterization, biodegradation and cytotoxicity of thermoplastic starch and ethylene-vinyl alcohol copolymer blends

Ethylene-vinyl alcohol samples containing 27 and 38 % ethylene were used to prepare blends containing 30 and 50 % thermoplastic starch (TPS) plasticized with glycerol. Their biodegradability and cytotoxicity were studied by different techniques (XRD, DSC, TGA, CA, ATR-FTIR, SEM). TPS presence significantly affected copolymer behavior, as confirmed by the appearance of O–H IR 1000–1170 cm− 1 bands and overall reduction of EVOH crystallinity, melting point, thermal stability and hydrophobicity. Biodegradation was more efficient in the presence of TPS and resulted in the formation of a robust biofilm by a consortium of three bacteria. A lower ethylene content facilitated biodegradation, making the material easier to metabolize. The mineralization percentages obtained after a 40-day bioassay at 45 ◦C were up to 66 % (EVOH-27/TPS 50:50). In vitro cytotoxicity assay demonstrated no cytotoxicity before and after biodegradation. EVOH/TPS blends are presented as a potential environmentally friendly alternative to pure synthetic polymersThe authors want to thank the Spanish Ministry of Science and Innovation for financial support (project PID2019-104812GB-I00) and FUAM, Universidad Autonoma de Madrid, Spain (project n◦ 820053

A Non-Commutative Extension of MELL

We extend multiplicative exponential linear logic (MELL) by a non-commutative, self-dual logical operator. The extended system, called NEL, is defined in the formalism of the calculus of structures, which is a generalisation of the sequent calculus and provides a more refined analysis of proofs. We should then be able to extend the range of applications of MELL, by modelling a broad notion of sequentiality and providing new properties of proofs. We show some proof theoretical results: decomposition and cut elimination. The new operator represents a significant challenge: to get our results we use here for the first time some novel techniques, which constitute a uniform and modular approach to cut elimination, contrary to what is possible in the sequent calculus

The Universal Declaration of Human Rights at 70: Putting Human Rights at the heart of the design, development and deployment of artificial intelligence

ESR

Enzyme-induced graft polymerization for preparation of hydrogels: synergetic effect of laccase-immobilized-cryogels for pollutants adsorption

The use of polyethylene oxide-polypropylene oxide-polyethylene oxide block-copolymers as a mediator in the laccase-induced graft polymerization of diacrylic derivate of polyethylene glycols resulted in the formation of PEG-g-F68 hydrogels. The proper oxygen content in the reaction medium to obtain reasonable polymerization conversions (i.e., on one hand, laccase needs oxygen as substrate whereas, on the other, oxygen is a strong inhibitor of radical polymerizations) was achieved by the use of an enzymatic scavenging system consisting of glucose oxidase and glucose. Eventually, laccase was immobilized within the resulting PEG-g-F68 hydrogel with full preservation of enzyme activity. Laccases have been used for bioremediation purposes because of their ability to degrade phenolic compounds. Thus, laccase-immobilized PEG-g-F68 hydrogels were submitted to the ISISA (ice segregation induced self-assembly) process for preparation of laccase-immobilized PEG-g-F68 cryogels which exhibited a macroporous structure where immobilized laccase preserved almost total activity (ca. 90%) for a period exceeding three months after preparation. Synergy between macroporous structure (deriving from the ISISA process), amphiphilic domains (deriving from graft copolymer) and activity of the immobilized enzyme provided outstanding adsorption capabilities to the cryogels (up to 235 mg g(-1))This work was supported by MICINN (MAT2009-10214, MAT2009-09671 and PET2008-0168-01) and CSIC (200660F011). M. N. and S. N. thank CSIC for a research contract and a PhD fellowship, respectively. C. A. thanks MICINN for a Ramon y Cajal contract. We thank F. Pinto for assistance with SEM.Peer reviewe

The role of bounded rationality and imperfect information in subgame perfect implementation - an empirical investigation

In this paper we conduct a laboratory experiment to test the extent to which Moore and Repullo’s subgame perfect implementation mechanism induces truth-telling, both in a setting with perfect information and in a setting where buyers and sellers face a small amount of uncertainty regarding the good’s value. We find that Moore–Repullo mechanisms fail to implement truth-telling in a substantial number of cases even under perfect information about the valuation of the good. Our data further suggests that a substantial proportion of these lies are made by subjects who hold pessimistic beliefs about the rationality of their trading partners. Although the mechanism should—in theory—provide incentives for truth-telling, many buyers in fact believe that they can increase their expected monetary payoff by lying. The deviations from truth-telling become significantly more frequent and more persistent when agents face small amounts of uncertainty regarding the good’s value. Our results thus suggest that both beliefs about irrational play and small amounts of uncertainty about valuations may constitute important reasons for the absence of Moore–Repullo mechanisms in practice

Structure of a bacterial type III secretion system in contact with a host membrane in situ

Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform– ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking ‘pump-action’ conformational changes that underpin effector injection

Oligothiophene Interlayer Effect on Photocurrent Generation for Hybrid TiO₂/P3HT Solar Cells

Planells M, Abate A, Snaith HJ, Robertson N. Oligothiophene Interlayer Effect on Photocurrent Generation for Hybrid TiO /P3HT Solar Cells. ACS Applied Materials & Interfaces. 2014;6(19):17226-17235.A series of conjugated 3-hexylthiophene derivatives with a cyanoacrylic acid group has been prepared with conjugation length from one up to five thiophene units (1T–5T). The UV–vis spectra, photoluminescence spectra, electrochemical data and DFT calculations show lowering of LUMO energies and red-shift of absorption into the visible as the thiophene chain length increases. TiO2/P3HT solar cells were prepared with prior functionalization of the TiO2 surface by 1T–5T and studies include cells using undoped P3HT and using P3HT doped with H-TFSI. Without H-TFSI doping, photocurrent generation occurs from both the oligothiophene and P3HT. Doping the P3HT with H-TFSI quenches photocurrent generation from excitation of P3HT, but enables very effective charge extraction upon excitation of the oligothiophene. In this case, photocurrent generation increases with the light harvesting ability of 1T–5T leading to a highest efficiency of 2.32% using 5T. Overall, we have shown that P3HT can act in either charge generation or in charge collection, but does not effectively perform both functions simultaneously, and this illustrates a central challenge in the further development of TiO2/P3HT solar cells

Contradictory reasoning network:an EEG and FMRI study

Contradiction is a cornerstone of human rationality, essential for everyday life and communication. We investigated electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) in separate recording sessions during contradictory judgments, using a logical structure based on categorical propositions of the Aristotelian Square of Opposition (ASoO). The use of ASoO propositions, while controlling for potential linguistic or semantic confounds, enabled us to observe the spatial temporal unfolding of this contradictory reasoning. The processing started with the inversion of the logical operators corresponding to right middle frontal gyrus (rMFG-BA11) activation, followed by identification of contradictory statement associated with in the right inferior frontal gyrus (rIFG-BA47) activation. Right medial frontal gyrus (rMeFG, BA10) and anterior cingulate cortex (ACC, BA32) contributed to the later stages of process. We observed a correlation between the delayed latency of rBA11 response and the reaction time delay during inductive vs. deductive reasoning. This supports the notion that rBA11 is crucial for manipulating the logical operators. Slower processing time and stronger brain responses for inductive logic suggested that examples are easier to process than general principles and are more likely to simplify communication. © 2014 Porcaro et al

Timing is everything: the regulation of type III secretion

Type Three Secretion Systems (T3SSs) are essential virulence determinants of many Gram-negative bacteria. The T3SS is an injection device that can transfer bacterial virulence proteins directly into host cells. The apparatus is made up of a basal body that spans both bacterial membranes and an extracellular needle that possesses a channel that is thought to act as a conduit for protein secretion. Contact with a host-cell membrane triggers the insertion of a pore into the target membrane, and effectors are translocated through this pore into the host cell. To assemble a functional T3SS, specific substrates must be targeted to the apparatus in the correct order. Recently, there have been many developments in our structural and functional understanding of the proteins involved in the regulation of secretion. Here we review the current understanding of protein components of the system thought to be involved in switching between different stages of secretion