A functional polymeric material based on hybrid electrochemically controlled junctions

A thin film polymeric junction was fabricated which yields a molecular electronic device functionally able to learn, i.e. to respond coherently to an external training signal. The fabricated structure is based upon electrochemical control of electronic current in a conducting polymer in contact with a solid electrolyte polymer. This functional behavior bears some resemblance to simple cases of biological learning processes. We report a comprehensive electronic characterization of the device function. Additional study was performed in order to estimate the possibility of the integration of such kinds of devices in statistical adaptive networks.     

Confinement effects on the kinetics of formation of sequential semi-interpenetrating polymer networks

Summary Peculiarities of formation kinetics of sequential semi-interpenetrating polymer networks based on crosslinked polyurethane with different cross-linking density and linear polystyrene and polybutylmethacrylate have been studied. Polyurethane networks were synthesized differing in molecular mass M_c of the chains between cross-links. Monomeric styrene and butyl methacrylate were introduced into these networks by swelling them in monomers up to equilibrium. The kinetics of polymerization of monomers in swollen networks was investigated. The experimental data show the dependence of the kinetic parameters of polymerization on M_c, this dependence being different for various monomers. Sharp discrepancy in molecular mass distribution of polymers formed in various matrices has been observed. The differences in dependencies of reaction kinetics and molecular mass distribution are supposed to be connected to various dependence of the chain growth and termination of various monomers on the density of network, i.e. on the confinements imposed by the intranetwork space.     

A camera-joystick for sound-augmented non-visual navigation and target acquisition: a case study

This paper presents the results of a comparative study of user input with a camera-joystick and a manual joystick used in a target acquisition task when neither targets nor pointer could be perceived visually. The camera-joystick is an input technique in which each on-screen item is accessible from the center with a predefined vector of head motion. Absolute pointing was implemented with an acceleration factor of 1.7 and a moving average on 5 detected head positions. The underlying assumption was that, in order to provide a robust input for blind users, the interaction technique has to be based on perceptually well-discriminated human movements, which compose a basic framework of an accessible virtual workspace demanding minimum external auxiliary cues. The target spots, having a diameter of 35 mm and a distance between the centers of adjacent spots of 60 mm, were arranged in a rectangular grid of 5 rows by 5 columns. The targets were captured from a distance of 600 mm. The results have shown that the camera input is a promising technique for non-visual human–computer interaction. The subjects demonstrated, more than twice, better performance in the target acquisition task with the camera-joystick versus the manual joystick. All the participants reported that the camera-joystick was a robust and preferable input technique when visual information was not available. Blind interaction techniques could be significantly further improved allowing a user-dependent activation of the navigational cues to better coordinate feedbacks with exploratory behavior.     

Improved magnetic trapped field in thin-wall YBCO single-domain samples by high-pressure oxygen annealing

Oxygen high pressure (up to 16 MPa) has been introduced in the oxygen-annealing step necessary to make the YBa₂Cu₃O_x phase superconducting (change x from 6 to about 7). It enables a displacement in the equilibrium phase diagram towards higher temperatures, which means the possibility to achieve the same final oxygen content as the one at low temperature, but with the benefit of higher diffusion rates. Initial development made on thin bars (1.5–3 mm thick) has confirmed the interest of using a high pressure of oxygen. TEM observations have shown an increase of twin density associated with higher Jc. This is in agreement with other works claiming the possibility of higher Jc by twin engineering, and more precisely by twin refinement while annealing at high temperature. We report the successful application of this process without any adjustment to so-called thin-wall single-domain samples. These samples are obtained by growing a crystal on a pellet already shaped with an array of holes. The advantage is that, as far as diffusion processes are concerned, the typical length is not anymore the diameter of the sample, but the thickness of the walls between holes. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6 T vs. 0.3 T at 77 K) in a rather short annealing time (about 3 days). Microstructures as well as magneto-optical observations of plain and thin-wall samples evidenced a reduction of cracks in the thin-wall samples. Improved performances were confirmed by further characterizations performed from 77 down to 20 K using the pulse-field facilities of the LNCMP at Toulouse.     

A Novel Triple-Action Inhibitor Targeting B-Cell Receptor Signaling and BRD4 Demonstrates Preclinical Activity in Chronic Lymphocytic Leukemia

B-cell chronic lymphocytic leukemia (CLL) results from intrinsic genetic defects and complex microenvironment stimuli that fuel CLL cell growth through an array of survival signaling pathways. Novel small-molecule agents targeting the B-cell receptor pathway and anti-apoptotic proteins alone or in combination have revolutionized the management of CLL, yet combination therapy carries significant toxicity and CLL remains incurable due to residual disease and relapse. Single-molecule inhibitors that can target multiple disease-driving factors are thus an attractive approach to combat both drug resistance and combination-therapy-related toxicities. We demonstrate that SRX3305, a novel small-molecule BTK/PI3K/BRD4 inhibitor that targets three distinctive facets of CLL biology, attenuates CLL cell proliferation and promotes apoptosis in a dose-dependent fashion. SRX3305 also inhibits the activation-induced proliferation of primary CLL cells in vitro and effectively blocks microenvironment-mediated survival signals, including stromal cell contact. Furthermore, SRX3305 blocks CLL cell migration toward CXCL-12 and CXCL-13, which are major chemokines involved in CLL cell homing and retention in microenvironment niches. Importantly, SRX3305 maintains its anti-tumor effects in ibrutinib-resistant CLL cells. Collectively, this study establishes the preclinical efficacy of SRX3305 in CLL, providing significant rationale for its development as a therapeutic agent for CLL and related disorders.     

Migration of specific planar grain boundaries in bicrystals: application of magnetic fields and mechanical stresses

Recent research on the dynamics of planar grain boundaries is reviewed. Novel measuring techniques developed for in situ observation and recording of magnetically and stress driven grain boundary migration are presented. The results of migration measurements obtained on bismuth, zinc and aluminum bicrystals are addressed. The experiments revealed that the inclination of a 〈112〉 tilt boundary in Bi has a very strong influence on its mobility. The migration of planar 〈10$ \bar 1 $ \bar 1 0〉 tilt grain boundaries with different misorientation angles was measured in situ in bicrystals of high purity zinc. The results proved that there is a pronounced misorientation dependence of grain boundary mobility in the investigated angular range. The shear stress induced migration of planar symmetric 〈100〉 tilt boundaries in aluminum bicrystals was observed to be accompanied by a lateral translation of the adjacent grains. The coupling between boundary motion and shearing is not confined to low angle and some low Σ high angle boundaries, but occurs also for noncoincidence high angle 〈100〉 tilt boundaries. It has been found that also for stress induced grain boundary motion there is a misorientation dependence of the migration activation parameters. Lower values of the activation enthalpy and the pre-exponential mobility factor can be associated with boundaries with tilt angles close to low Σ CSL orientation relationships.     

Injection of Microporous Annealing Particle (MAP) Hydrogels in the Stroke Cavity Reduces Gliosis and Inflammation and Promotes NPC Migration to the Lesion

With the number of deaths due to stroke decreasing, more individuals are forced to live with crippling disability resulting from the stroke. To date, no therapeutics exist after the first 4.5 h after the stroke onset, aside from rest and physical therapy. Following stroke, a large influx of astrocytes and microglia releasing proinflammatory cytokines leads to dramatic inflammation and glial scar formation, affecting brain tissue's ability to repair itself. Pathological conditions, such as a stroke, trigger neural progenitor cells (NPCs) proliferation and migration toward the damaged site. However, these progenitors are often found far from the cavity or the peri‐infarct tissue. Poststroke tissue remodeling results in a compartmentalized cavity that can directly accept a therapeutic material injection. Here, this paper shows that the injection of a porous hyaluronic acid hydrogel into the stroke cavity significantly reduces the inflammatory response following stroke while increasing peri‐infarct vascularization compared to nonporous hydrogel controls and stroke only controls. In addition, it is shown that the injection of this material impacts NPCs proliferation and migration at the subventricular zone niche and results, for the first time, in NPC migration into the stroke site.     

Analysis of microstructure and microhardness of Zr-2.5Nb processed by High-Pressure Torsion (HPT)

Nanostructured materials have been widely studied due to the improvement of their mechanical properties comparing to those of coarse grain materials. The present work intended to analyze the microstructure and microhardness of Zr-2.5Nb processed by high-pressure torsion (HPT), one of the severe plastic deformation techniques. The deformations were carried out at room temperature using a pressure of 5?GPa and 5 anvil turns. Vickers indentation was used to evaluate the microhardness of the samples. Transmission electron microscopy and X-ray diffraction were used to analyze the microstructure. The results showed a significant refinement from the initial microstructure achieving nanometric grain size around 50?nm and phase transformation α?→?ω?+?β_I induced by shear. The Vickers microhardness values of the material submitted to HPT technique were significantly higher than those of non-deformed material. Also, HPT procedure resulted in a huge grain refinement of the material and in phase transformation.     

Fullerene: biomedical engineers get to revisit an old friend

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