On chirality of slime mould

© 2015 Elsevier Ireland Ltd. Left-right patterning and lateralised behaviour is an ubiquitous aspect of plants and animals. The mechanisms linking cellular chirality to the large-scale asymmetry of multicellular structures are incompletely understood, and it has been suggested that the chirality of living cells is hardwired in their cytoskeleton. We examined the question of biased asymmetry in a unique organism: the slime mould Physarum polycephalum, which is unicellular yet possesses macroscopic, complex structure and behaviour. In laboratory experiment using a T-shape, we found that Physarum turns right in more than 74% of trials. The results are in agreement with previously published studies on asymmetric movement of muscle cells, neutrophils, liver cells and growing neural filaments, and for the first time reveal the presence of consistently-biased laterality in the fungi kingdom. Exact mechanisms of the slime mould's direction preference remain unknown

Physarum Polycephalum changes polyaniline properties

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Nanogap structures for molecular nanoelectronics

This study is focused on the realization of nanodevices for nano and molecular electronics, based on molecular interactions in a metal-molecule-metal (M-M-M) structure. In an M-M-M system, the electronic function is a property of the structure and can be characterized through I/V measurements. The contact between the metals and the molecule was obtained by gold nanogaps (with a dimension of less than 10 nm), produced with the electromigration technique. The nanogap fabrication was controlled by a custom hardware and the related software system. The studies were carried out through experiments and simulations of organic molecules, in particular oligothiophenes

T cell phenotypes in COVID-19 - a living review

COVID-19 is characterized by profound lymphopenia in the peripheral blood, and the remaining T cells display altered phenotypes, characterized by a spectrum of activation and exhaustion. However, antigen-specific T cell responses are emerging as a crucial mechanism for both clearance of the virus and as the most likely route to long-lasting immune memory that would protect against re-infection. Therefore, T cell responses are also of considerable interest in vaccine development. Furthermore, persistent alterations in T cell subset composition and function post-infection have important implications for patients’ long-term immune function. In this review, we examine T cell phenotypes, including those of innate T cells, in both peripheral blood and lungs, and consider how key markers of activation and exhaustion correlate with, and may be able to predict, disease severity. We focus on SARS-CoV-2-specific T cells to elucidate markers that may indicate formation of antigen-specific T cell memory. We also examine peripheral T cell phenotypes in recovery and the likelihood of long-lasting immune disruption. Finally, we discuss T cell phenotypes in the lung as important drivers of both virus clearance and tissue damage. As our knowledge of the adaptive immune response to COVID-19 rapidly evolves, it has become clear that while some areas of the T cell response have been investigated in some detail, others, such as the T cell response in children remain largely unexplored. Therefore, this review will also highlight areas where T cell phenotypes require urgent characterisation

The role and uses of antibodies in COVID-19 infections: a living review

Coronavirus disease 2019 has generated a rapidly evolving field of research, with the global scientific community striving for solutions to the current pandemic. Characterizing humoral responses towards SARS-CoV-2, as well as closely related strains, will help determine whether antibodies are central to infection control, and aid the design of therapeutics and vaccine candidates. This review outlines the major aspects of SARS-CoV-2-specific antibody research to date, with a focus on the various prophylactic and therapeutic uses of antibodies to alleviate disease in addition to the potential of cross-reactive therapies and the implications of long-term immunity

Nanogap structures for molecular electronics and biosensing

Molecular transport characterization is an active part of the research field in nanotechnology. In this interesting branch the self-assembly approach is highly exploited; it consists in spontaneous formation of highly ordered monolayers on various substrate surfaces. Self-assembled monolayers (SAMs) have found their applications in various areas, such as nanoelectronics, surface engineering, biosensing, etc. An important area in biosensing is the electrochemical detection, that enables sensing of dierent biomarkers with an important role, for many dierent applications in biomedical diagnostics or in monitoring of biological systems. Various test structures have been developed in order to carry out characterizations of self-assembled molecules, and numerous reports have been published in the past several years on the transport characteristics. This thesis' purpose is the single protein biomolecular sensing, that could become the starting point for monitoring drugs, developing clean energy systems, realizing bio-opto-electronic transistors... The possibility to cover so many fields is related to the kind of proteins, molecules, bioelements that will be inserted inside sensors. Biomolecular sensing has to be thought in order to reach a result with the better compromise between instrumentation versatility and measurements precision. The main underlying idea is to use single molecules as active elements in nano-devices. As a consequence, the proper realization of a molecule-electrode contact is a crucial issue. What is needed by author is something versatile, precize, cheap, at single molecule level and able to record measurements in few time in order to do statistical characterizations. The final goal of this work is a platform system adapt for both industry and research field. Electrical nanogap devices are the main character of this work. They have proven good performances as element for detecting small quantities of biomolecules, allowing direct transduction of biomolecular signals into useful electrical ones such as resistance/impedance, capacitance/dielectric, or field effect. Nanogaps are now one of the most busy area of research in the nanotechnology world. Moreover, these structures do not require feedback to maintain the mutual arrangement (comparing with conducting tip AFM) and are less stochastic with respect to electrochemical cells. Several techniques can be applied to nanogap fabrication: mechanically broken or positioned junctions, nano-scale lithography by Synchrotron radiation sources, electrochemical deposition and etching, and electromigration. None of these techniques is presently able to give precise control as to thefinal gap size. In this thesis the electromigration approach has been choosen, because of several useful characteristics. It is cost eective, because of the relatively low complexity of the required equipment. It can be embedded into a lab-on-chip system, thus exploiting the possibility to tailor the gap formation process by means of a digital loop control system. To this end, it just requires a conventional microchip fabrication process. It allows the parallelization with a smart packaging through which it is possible to produce more probes at the same time and perform many measurements in contemporary. The employment of nanogaps, as an instrumentation for the molecular charac- terization, has also some issues that have to be considered in order to obtain useful measurements. To characterize molecules the leakedge must be not higher than some pA to avoid the noise overcome the signal. Nanogap platform is perfect for molecular electronics. The experiments have been developed in dry way, as a consequence the solutions were evaporated before the measurement starting. This brought several problems cause biochemical analysis requires liquid solution in order to avoid an untimely death of the bio-elements tha has to be characterized. Considering a future developement, an improvement is necessary in terms of a system able to work with salty solutions without damaging the microchip's probes. Therefore it is a necessary a set-up allowing the anchorage of a microfluidic part. At the same time it is necessary to keep in mind that the presence of a new system has to not overcome the molecule signal, maintaining the leakedge under some tens of pA

Hysteresis loop and cross-talk of organic memristive devices

Similarly to inorganic memristors, the organic memristive devices reveal a variation of the hysteresis loop upon the frequency of the applied bias voltage. The on/off ratio of the conductivity increases from 4 to 1000 times for the variation of time delay (equilibration after the application of the voltage increment) from 5 to 60 s. Being implemented in multi-element electrical circuits memristive devices provide a cross-talk, leading to an equilibration trend of the conductivity values. This effect is mainly related to the formation of stable signal pathways

A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC) slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device