Artificial synapses based on HfOx/TiOymemristor devices for neuromorphic applications.

As a result of enormous progress in nanoscale electronics, interest in artificial intelligence (AI) supported systems has also increased greatly. These systems are typically designed to process computationally intensive data. Parallel processing neural network architectures are particularly noteworthy for their ability to process dense data at high speeds, making them suitable candidates for AI algorithms. Due to their ability to combine processing and memory functions in a single device, memristors offer a significant advantage over other electronic platforms in terms of area scaling efficiency and energy savings. In this study, single-layer and bilayer metal-oxide HfOxand TiOymemristor devices inspired by biological synapses were fabricated by pulsed laser and magnetron sputtering deposition techniques in high vacuum with different oxide thicknesses. The structural and electrical properties of the fabricated devices were analysed using x-ray reflectivity, x-ray photoelectron spectroscopy, and standard two-probe electrical characterization measurements. The stoichiometry and degree of oxidation of the elements in the oxide material for each thin film were determined. Moreover, the switching characteristics of the metal oxide upper layer in bilayer devices indicated its potential as a selective layer for synapse. The devices successfully maintained the previous conductivity values, and the conductivity increased after each pulse and reached its maximum value. Furthermore, the study successfully observed synaptic behaviours with long-term potentiation, long-term depression (LTD), paired-pulse facilitation, and spike-timing-dependent plasticity, showcasing potential of the devices for neuromorphic computing applications.

Comparison of clopidogrel vs. ticagrelor medication adherence in patients with acute coronary syndrome.

OBJECTIVE: Medication nonadherence to dual antiplatelet therapy increases major cardiovascular events. In this study, we investigated patients' post-acute coronary syndrome (ACS) medication adherence to clopidogrel and ticagrelor over a 12-month period. Furthermore, we also examined the factors that may affect medication adherence in this patient population. PATIENTS AND METHODS: This study included 509 patients who were scheduled for dual antiplatelet therapy for one year following ACS (October 2018-December 2019). A proportion of days covered (PDC) method, based on a pharmacy database system, was used to determine their medication adherence. Medication adherence was defined as > 80% PDC. RESULTS: No difference was found between clopidogrel and ticagrelor in terms of medication adherence (68.3% vs. 64.6%, p = 0.39). Moreover, higher education levels (B = 3.24, CI: 1.17-8.9, p = 0.023) and percutaneous coronary intervention (PCI) as a revascularization option (B = 0.35, CI: 0.17-0.71, p = 0.004) predicted medication adherence independently. CONCLUSIONS: In this research, medication adherence was found to be similar between the clopidogrel and ticagrelor groups. It was also predicted by higher education levels and revascularization with PCI.

Conformational Flexibility and Self-Association of Fibrinogen in Concentrated Solutions.

We studied the hydrodynamic behavior of fibrinogen, a blood plasma protein involved in blood clotting, in a broad 0.3-60 mg/mL range of concentration and 5-42 °C temperature using pulsed-field gradient 1H NMR-diffusometry. Arrhenius plots revealed the activation energy for fibrinogen diffusion Ed = 21.3 kJ/mol at 1.4 mg/mL and 28.4 kJ/mol at 38 mg/mL. We found a dramatic slowdown in fibrinogen self-diffusion with concentration beginning at 1.7-3.4 mg/mL, which deviated from the standard hard-particle behavior, suggesting a remarkable intermolecular entanglement. This concentration dependence was observed regardless of the absence or presence of the GPRP peptide (inhibitor of fibrin polymerization), and also in samples free of fibrin oligomers. By contrast, diffusivity of fibrinogen variant I-9 with truncated C-terminal portions of the Aα chains was much less concentration-dependent, indicating the importance of intermolecular linkages formed by the αC regions. Theoretical models combined with all-atom molecular dynamics simulations revealed partially bent fibrinogen solution conformations that interpolate between a flexible chain and a rigid rod observed in the crystal. The results obtained illuminate the important role of the αC regions in modulating the fibrinogen molecular shape through formation of weak intermolecular linkages that control the bulk properties of fibrinogen solutions.

Gelation of rhamnogalacturonan I is based on galactan side chain interaction and does not involve chemical modifications.

The article presents the structural principles of microwave-induced formation of new gel type from pectic rhamnogalacturonan I (RG-I). The backbone of gel-forming RG-I does not contain consecutive galacturonic residues and modifying groups that can be the cause of junction zone formation as it occurs in course of classical ways of pectin gelation. Microwave irradiation does not cause destruction and chemical modifications of RG-I. Removal of half of galactan chains from RG-I leads to loss of gelling capability pointing out on their leading role in this process. Rising of intensity of the bands attributed to galactose and glycosidic linkages in RG-I gel comparing to solution where this polymer exists as molecule associate indicates that the spatial organization of galactans in gel is changed. A model of the RG-I gelation is proposed: being destabilized at volumetric microwave heating RG-I associates are repacked forming network where RG-I molecules are entangled by galactan chains.

Structure of Scots pine defensin 1 by spectroscopic methods and computational modeling.

Defensins are part of the innate immune system in plants with activity against a broad range of pathogens, including bacteria, fungi and viruses. Several defensins from conifers, including Scots pine defensin 1 (Pinus sylvestris defensin 1, (PsDef1)) have shown a strong antifungal activity, however structural and physico-chemical properties of the family, needed for establishing the structure-dynamics-function relationships, remain poorly characterized. We use several spectroscopic and computational methods to characterize the structure, dynamics, and oligomeric state of PsDef1. The three-dimensional structure was modeled by comparative modeling using several programs (Geno3D, SWISS-MODEL, I-TASSER, Phyre(2), and FUGUE) and verified by circular dichroism (CD) and infrared (FTIR) spectroscopy. Furthermore, FTIR data indicates that the structure of PsDef1 is highly resistant to high temperatures. NMR diffusion experiments show that defensin exists in solution in the equilibrium between monomers and dimers. Four types of dimers were constructed using the HADDOCK program and compared to the known dimer structures of other plant defensins. Gaussian network model was used to characterize the internal dynamics of PsDef1 in monomer and dimer states. PsDef1 is a typical representative of P. sylvestris defensins and hence the results of this study are applicable to other members of the family.

Physicochemical properties of complex rhamnogalacturonan I from gelatinous cell walls of flax fibers.

The physicochemical properties of flax fiber cell wall rhamnogalacturonan I (RG-I) and its fragments, obtained after galactanase treatment (fraction G1), were characterized. RG-I retains its hydrodynamic volume after its molecular weight decreases by approximately half, as revealed by SEC. Two techniques, DLS and NMR, with different principles of diffusion experiment were used to establish the reasons for this property of RG-I. Three possible types of particles were revealed by DLS depending on the concentration of the RG-I and G1 solutions (2-2.5, 15-20, and 150-200 nm). It was determined by BPP-LED experiments that the backbone of the RG-I was 1.3-1.9-fold more mobile than the side chains. The obtained data suggest a novel type of pectin spatial organization-the formation of RG-I associates with the backbone at the periphery and the interaction between the side chains to form a core zone.

Novel biomimetic systems based on amphiphilic compounds with a diterpenoid fragment: role of counterions in self-assembly.

Novel biomimetic systems are designed based on cationic surfactants composed of an isosteviol moiety and different counterions, namely bromide (S1) and tosylate (S2). The counterion structure is shown to play a crucial role in the surfactant association. A number of methods used provide evidence that only one type of aggregate, i.e., micelles are observed in the S2 systems, while a concentration-dependent association occurs in the case of S1. The DLS and fluorescence anisotropy measurements reveal that the micelle-vesicle-micelle transitions probably occur with the S1 system. The occurrence of small aggregates near the critical micelle concentration with radii of 2.5 nm is supported by NMR self-diffusion data. The Orange OT solubilization results strongly support the idea of a second threshold in the S1 system around 0.025 mM and provide evidence that hydrophobic domains occur in the aggregates. The latter property and the capacity to integrate with the lipid bilayer make it possible to suggest the newly synthesized surfactants as effective nanocontainers for hydrophobic guests.

Blood and urine cadmium and bioelements profile in nickel-cadmium battery workers in Serbia.

Although cadmium (Cd) is extensively used for nickel-cadmium battery production, few recent reports are available on the effect of this toxic metal on the imbalance of biometals in occupational exposure. The current study was carried out to determine the Cd level and its effect on the content of bioelements: zinc, cooper, magnesium, and iron in blood and urine of workers exposed to Cd during nickel-cadmium battery production. beta(2)-microglobulins (beta(2)-MG), as indicators of kidney damage, were determined in urine.The study group comprised 32 male nickel-cadmium battery workers, and the control group had 15 male construction workers with no history of Cd exposure. Levels of Cd and bioelements were determined in blood and urine by atomic absorption spectrophotometry.Cd concentration in blood of exposed workers was around 10 microg/L and in urine ranged from 1.93 to 8.76 microg/g creatinine (cr). Urine Cd concentration was significantly higher in exposed workers than in the controls, although no statistical difference in beta(2)-MG content was observed in urine between the two groups. Blood Zn and Mg level were significantly reduced and urine Zn level was increased in Cd-exposed group when compared with controls.The mean Cd concentrations in blood and urine did not exceed the recommended reference values of 10 microg/L in blood and 10 microg/g cr in urine. Cd exposure resulted in disturbances of Zn in blood and urine and Mg in blood but had no effect on Cu and Fe content in biological fluids.