Gamma Phase Research Articles

Metal‐Free, Light‐Catalyzed ATRP For the Synthesis of Functional PVDF‐Based Block Copolymers and Their Characterization

AbstractThe synthesis and characterization of poly(vinylidene fluoride) (PVDF)‐based block copolymers using a metal‐free light‐catalyzed atom transfer radical polymerization (ATRP) approach are described. A PVDF macroinitiator with C─Br bonds at both ends of the chain is synthesized, and an organic photoredox catalyst (OPRC) is used to control the process. The metal‐free process expands the possibilities for the synthesis and application of PVDF‐based block copolymers, as it allows the use of monomers that is previously incompatible with classical ATRP due to their interaction with metal catalysts. The synthesized block copolymers are characterized structurally and thermally as powder materials and in thin films. Fourier‐transform infrared spectroscopy (FT‐IR) analysis revealed that the crystalline phase of PVDF changes when thin films are formed. Specifically, the disappearance of the FT‐IR peaks related to the gamma phase and the presence of characteristic peaks related to the alpha and beta phases indicate that film formation rearranged the PVDF chains, leading to changes in their crystalline phases. These PVDF‐based block copolymers have unique properties, including high thermal stability, chemical resistance, and piezoelectricity, making them potential candidates for use in various fields, such as biomedical engineering, energy storage, and electronic devices.

Dissociation of attentional state and behavioral outcome using local field potentials.

Successful behavior depends on attentional state and other factors related to decision-making, which may modulate neuronal activity differently. Here, we investigated whether attentional state and behavioral outcome (i.e., whether a target is detected or missed) are distinguishable using the power and phase of local field potential (LFP) recorded bilaterally from area V4 of two male rhesus monkeys performing a cued visual attention task. To link each trial's outcome to pairwise measures of attention that are typically averaged across trials, we used several methods to obtain single-trial estimates of spike count correlation and phase consistency. Surprisingly, while attentional location was best discriminated using gamma and high-gamma power, behavioral outcome was best discriminated by alpha power and steady-state visually evoked potential. Power outperformed absolute phase in attentional/behavioral discriminability, although single-trial gamma phase consistency provided reasonably high attentional discriminability. Our results suggest a dissociation between the neuronal mechanisms that regulate attentional focus and behavioral outcome.Significance statement Targets appearing at the attended location are detected more accurately than those at the unattended location. However, attention may not be the only factor regulating the behavioral outcome. We investigated whether the effects of behavioral outcome and attentional state could be differentiated using the local field potentials recorded from macaque visual area V4. We used various methods to obtain single-trial estimates of trial-wise measures like correlations and phase consistency. Remarkably, we found that while attentional location was most effectively discerned through gamma and high-gamma power, behavioral outcomes were better distinguished by alpha power and steady-state visually evoked potentials. These results suggest distinct mechanisms underlying attention and behavioral outcome, thus emphasizing the roles of additional factors in modulating the behavioral outcome.

Mechanical and microstructural profiling of additively manufactured cobalt–nickel functional gradient structure

In this study, a functional gradient material (FGM) structure composed of a nickel alloy (IN718), and a cobalt alloy (CoCrMo) was additively manufactured using a co-axial powder-fed laser-directed energy deposition (L-DED) system. The high manufacturing flexibility of L-DED enabled the seamless deposition of IN718-CoCrMo FGM structure through interfacial bonding driven by thermal gradient and cool-down mechanisms. Microscopic analysis confirmed the absence of cracks or delamination in the CoCrMo-IN718 interfacial bonding region. The SEM-EBSD microstructural analysis and micro-hardness testing were performed on the as-printed CoCrMo-IN718 FGM primarily to correlate the hardness properties-microstructural grain phase morphology between the parent alloys and their interfacial bonding region. It was observed that the average hardness of the CoCrMo-IN718 interface zone (322.83 HV1) fell between IN718 (268.67 HV1) and CoCrMo (359.75 HV1) regions. The EBSD analysis reports indicated that along the build direction of CoCrMo-IN718 FGM, the preferential grain orientation aligned in [100] with grain structure transitioning from equiaxed → columnar → elongated columnar dendrites → equiaxed grain, predominantly comprised of face-centered cubic (FCC)-gamma (γ) phase crystal structures. Relatively, coarser grain structures were observed in the interface bonding region, attributed to the analogous crystallography space groups, and prolonged localized thermal gradients.

Theory and application of robust linear phase-shift algorithm for phase-shift deflectometry method

Based on the polynomial theory, the error propagation characteristics of the widely used N-step discrete Fourier transform (N-DFT) phase-shift algorithm were analyzed via theoretical analysis, under the effect of Gamma distortion and phase detuning. The results showed that the N-DFT algorithm could not simultaneously suppress both types of error. A robust linear phase-shift (RLPS) algorithm was designed, the performance of the RLPS and 8-DFT algorithms in terms of spectral response, detuning robustness, and GS/N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${G}_{S/N}$$\\end{document} was briefly analysis by Manuel Servin method. The Simulation analysis and comparison of the results show that the RLPS algorithm could suppress both types of error simultaneously, which exhibited better stability and accuracy than N-DFT and exponential algorithms, particularly in gradient measurement stability, peak-to-valley (PV) and root-mean-square (RMS) error suppression. Moreover, a physical experiment apparatus was built to test unidirectionally inclined plane mirror and concave mirror using the RLPS, N-DFT, and exponential algorithms. The results showed that the RLPS algorithm could significantly improve the measurement stability and accuracy in the presence of detuning and without screen Gamma calibration.

Neurophysiological, structural, and molecular alterations in the prefrontal and auditory cortices following noise-induced hearing loss

It is well established that hearing loss can lead to widespread plasticity within the central auditory pathway, which is thought to contribute to the pathophysiology of audiological conditions such as tinnitus and hyperacusis. Emerging evidence suggests that hearing loss can also result in plasticity within brain regions involved in higher-level cognitive functioning like the prefrontal cortex; findings which may underlie the association between hearing loss and cognitive impairment documented in epidemiological studies. Using the 40-Hz auditory steady state response to assess sound-evoked gamma oscillations, we previously showed that noise-induced hearing loss results in impaired gamma phase coherence within the prefrontal but not the auditory cortex. To determine whether region-specific structural or molecular changes accompany this differential plasticity following hearing loss, in the present study we utilized Golgi-Cox staining to assess dendritic organization and synaptic density, as well as Western blotting to measure changes in synaptic signaling proteins in these cortical regions. We show that following noise exposure, impaired gamma phase coherence within the prefrontal cortex is accompanied by alterations in pyramidal cell dendritic morphology and decreased expression of proteins involved in GABAergic (GAD65) and glutamatergic (NR2B) neurotransmission; findings that were not observed in the auditory cortex, where gamma phase coherence remained unchanged post-noise exposure. In contrast to the noise-induced effects we observed in the prefrontal cortex, plasticity in the auditory cortex was characterized by an increase in NR2B suggesting increased excitability, as well as increases in the synaptic proteins PSD95 and synaptophysin within the auditory cortex. Overall, our results highlight the disparate effect of noise-induced hearing loss on auditory and higher-level brain regions as well as potential structural and molecular mechanisms by which hearing loss may contribute to impaired cognitive and sensory functions mediated by the prefrontal and auditory cortices.

Comparative study of pure and mixed phase sulfurized‐carbon black in battery cathodes for lithium sulfur batteries

AbstractLithium‐sulfur battery (LSB) chemistry is regarded as one of the most promising contenders for powering next‐generation electronics, including electric vehicles. This is due to its high theoretical capacity, the use of inexpensive and environmentally friendly materials, and its alignment with climate‐smart manufacturing principles. Sulfur, the electroactive element in LSBs, undergoes lithiation to form a series of polysulfides, each contributing to the battery's energy density. However, this chemistry encounters several challenges, particularly concerning the stability of sulfur. Recent studies have shown that the presence of a full gamma phase of sulfur in an LSB cathode significantly enhances the capacity and overall cell performance. However, despite the advantages of cathodes with gamma sulfur, the characteristics of LSBs with mixed crystal phases of sulfur (alpha, beta, and gamma) have not been extensively studied. In this context, we developed a simple and cost‐effective synthesis method to produce both single‐phase (alpha) and mixed‐phase sulfur (primarily a mixture of alpha and gamma, with a trace of beta) and conducted their detailed physical and electrochemical characterization for use as electroactive cathode materials in LSBs. The cells fabricated using sulfur‐carbon black as the cathode delivered a specific capacity of approximately 640 mAh/g at a current density of 275 mA/g, demonstrating excellent cyclic stability over 50 cycles with a capacity retention of around 97%. This performance is superior to that of the sulfur‐baked carbon black composite cathode, which achieved 440 mAh/g at the same current density.

Impact of intermetallics on strength-ductility synergy in friction stir welded WE43 -AA7075 dissimilar joints

The present study used underwater friction stir welding (FSW) to join WE43 alloy and AA-7075 alloy, offering better thermal control than conventional FSW. This technique resulted in grain refinement and the formation of dual phases with a more uniform distribution of beta (ß) and gamma (γ) phases. These microstructural improvements enhanced the tensile strength and ductility in the stir zone (SZ). Specifically, in Air-FSW, the strength was 51 MPa with 35 % joint efficiency, whereas in Water-FSW, it increased to 103 MPa with 64.3 % joint efficiency. The transverse Water-FSW joint exhibited a 7.36 % increase in elongation. The reduction in residual stress in Water-FSW enhanced ductility compared to traditional joints. The evenly distributed hard intermetallic compounds also contributed to the improvements in strength and elongation.

Dissociation of attentional state and behavioral outcome using local field potentials.

Successful behavior depends on attentional state and other factors related to decision-making, which may modulate neuronal activity differently. Here, we investigated whether attentional state and behavioral outcome (i.e., whether a target is detected or missed) are distinguishable using the power and phase of local field potential (LFP) recorded bilaterally from area V4 of monkeys performing a cued visual attention task. To link each trial's outcome to pairwise measures of attention that are typically averaged across trials, we used several methods to obtain single-trial estimates of spike count correlation and phase consistency. Surprisingly, while attentional location was best discriminated using gamma and high-gamma power, behavioral outcome was best discriminated by alpha power and steady-state visually evoked potential. Power outperformed absolute phase in attentional/behavioral discriminability, although single-trial gamma phase consistency provided reasonably high attentional discriminability. Our results suggest a dissociation between the neuronal mechanisms that regulate attentional focus and behavioral outcome.

Frontal Cortex Hyperactivation and Gamma Desynchrony in Fragile X Syndrome: Correlates of Auditory Hypersensitivity.

Fragile X syndrome (FXS) is an X-linked disorder that often leads to intellectual disability, anxiety, and sensory hypersensitivity. While sound sensitivity (hyperacusis) is a distressing symptom in FXS, its neural basis is not well understood. It is postulated that hyperacusis may stem from temporal lobe hyperexcitability or dysregulation in top-down modulation. Studying the neural mechanisms underlying sound sensitivity in FXS using scalp electroencephalography (EEG) is challenging because the temporal and frontal regions have overlapping neural projections that are difficult to differentiate. To overcome this challenge, we conducted EEG source analysis on a group of 36 individuals with FXS and 39 matched healthy controls. Our goal was to characterize the spatial and temporal properties of the response to an auditory chirp stimulus. Our results showed that males with FXS exhibit excessive activation in the frontal cortex in response to the stimulus onset, which may reflect changes in top-down modulation of auditory processing. Additionally, during the chirp stimulus, individuals with FXS demonstrated a reduction in typical gamma phase synchrony, along with an increase in asynchronous gamma power, across multiple regions, most strongly in temporal cortex. Consistent with these findings, we observed a decrease in the signal-to-noise ratio, estimated by the ratio of synchronous to asynchronous gamma activity, in individuals with FXS. Furthermore, this ratio was highly correlated with performance in an auditory attention task. Compared to controls, males with FXS demonstrated elevated bidirectional frontotemporal information flow at chirp onset. The evidence indicates that both temporal lobe hyperexcitability and disruptions in top-down regulation play a role in auditory sensitivity disturbances in FXS. These findings have the potential to guide the development of therapeutic targets and back-translation strategies.

Performance of AI-Based Phase Picking and Event Association Methods after the Large 2023 Mw 7.8 and 7.6 Türkiye Doublet

ABSTRACT On 6 February 2023, a devastating earthquake doublet consisting of Mw 7.8 and 7.6 events separated by about 9 hr struck the southeastern part of Türkiye. The developing aftershock sequence contained thousands of events during the first few days and overwhelmed the routine algorithms handling their detection and location. In addition, several stations temporarily lost real-time contact and came online again later. At the same time the Omori decay of the aftershock event rate reduced the event frequency and allowed for inclusion of progressively smaller-magnitude events with time. One possibility to help deal with such a complex situation is the use of machine learning (ML) methods to generate earthquake catalogs with a substantially higher number of events. Here, we present high-resolution earthquake catalogs derived with two ML association methods for the first five days of the aftershock sequence of this doublet. In terms of the number of reliably located events, the event catalog created from PhaseNet picks and the GENIE phase association method outperforms both the routine regional catalog and the second ML-derived catalog obtained from the GaMMA phase association method. Although both GaMMA and GENIE catalogs detect about 6 times more events than the routine catalog, GENIE associates on average about double the phases to a single event than GaMMA, which results in better constrained event locations. The spatiotemporal evolution of the event rates is sensitive to changes in the network geometry due to variable station availability. During the first few days, no decay of the event rate in the enhanced catalog is observed due to the inclusion of progressively smaller-magnitude events with time and increased station availability. This study indicates that ML-derived earthquake catalogs for challenging time periods like the early aftershock sequences of large earthquakes have the potential to significantly improve routine event catalogs.

Control of working memory by phase–amplitude coupling of human hippocampal neurons

Retaining information in working memory is a demanding process that relies on cognitive control to protect memoranda-specific persistent activity from interference1,2. However, how cognitive control regulates working memory storage is unclear. Here we show that interactions of frontal control and hippocampal persistent activity are coordinated by theta–gamma phase–amplitude coupling (TG-PAC). We recorded single neurons in the human medial temporal and frontal lobe while patients maintained multiple items in their working memory. In the hippocampus, TG-PAC was indicative of working memory load and quality. We identified cells that selectively spiked during nonlinear interactions of theta phase and gamma amplitude. The spike timing of these PAC neurons was coordinated with frontal theta activity when cognitive control demand was high. By introducing noise correlations with persistently active neurons in the hippocampus, PAC neurons shaped the geometry of the population code. This led to higher-fidelity representations of working memory content that were associated with improved behaviour. Our results support a multicomponent architecture of working memory1,2, with frontal control managing maintenance of working memory content in storage-related areas3–5. Within this framework, hippocampal TG-PAC integrates cognitive control and working memory storage across brain areas, thereby suggesting a potential mechanism for top-down control over sensory-driven processes.

Unravelling the role of poly(methyl methacrylate) (PMMA) molecular weight in poly(vinylidene fluoride) (PVDF)/PMMA/expanded graphite (ExGr) blend nanocomposites: Insights into morphology, thermal behavior, electrical conductivity, and wetting property

Poly(vinylidene fluoride) (PVDF) based conducting polymer composites with carbon nanomaterials can be used for mechanical energy harvesting through piezoelectric or triboelectric effect. This study aims to investigate the influence of PMMA molecular weight on the electrical, thermal, and wetting properties of PVDF/40 wt.% PMMA blend nanocomposites reinforced with expanded graphite (ExGr). The blend nanocomposites with 40 wt.% PMMA have been prepared by solution blending method by using two different molecular weights of PMMA whose melt flow indices are 2 g/10 min and 2.3 g/10 min. The coexistence of the electroactive gamma and non-polar alpha phases of PVDF in the blend nanocomposites has been confirmed by X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry analyses. While overall crystallinity (%) of low molecular weight PMMA employed blend nanocomposites is lower than that of high molecular weight PMMA blended nanocomposites, the electroactive gamma phase has been found to increase in the former blend nanocomposites. The dispersion of graphite nanosheets has been observed to be better in high molecular weight PMMA employed blend nanocomposites which results in higher electrical conductivity. Impedance analysis of PVDF-40 wt.% PMMA-2 wt.% ExGr blend nanocomposite with high molecular weight PMMA results in enhanced interjunction capacitance (74.5 pF) in comparison to low molecular weight PMMA mixed blend nanocomposites (68 pF). Water contact angle (WCA) increases with molecular weight of PMMA and ExGr loading level. Thermogravimetric analysis has shown that the char content (above 500°C) is slightly higher for the blend with low molecular weight PMMA than with high molecular weight PMMA.

Effect of Flash Calcined Powders on the Properties of Spherical Alumina Granules

Three types of flash calcined powders with different specific surfaces and phases were selected to make alumina granules. The granulation was performed in a pan granulator as the spherical form. The hydrothermal and calcination conditions were applied to the granules. Physical, chemical and microstructural studies were applied to the hydrated and calcined granules. This study focussed on the thermal historical effects of the initial powders derived from bauxite on the granules. The least physical changes and the highest specific surface area were obtained for the granules prepared with flash calcined powder at 650°C. The hydrated granules can have boehmite, gamma and bayerite phases with rod, porous and plate morphologies, respectively. The presence of rod boehmite phase increases the strength of hydrated granules and plays an important role in the final strength. In the calcination stage, the phases transformed into the transition alumina and gamma phases with the growth of nanometer-sized crystals.

Eleven competing phases in the Heisenberg-Gamma ( JΓ ) ladder

The spin-orbit generated Γ interaction is known to induce strong frustration and to be significant in realistic models of materials. To gain an understanding of the possible phases that can arise from this interaction, it is of considerable interest to focus on a limited part of parameter space in a quasi one-dimensional model where high precision numerical results can be obtained. Here we study the Heisenberg–Gamma ( JΓ ) ladder, determining the complete zero temperature phase diagram by analyzing the entanglement spectrum (ES) and energy susceptibility. A total of 11 different phases can be identified, among them the well known rung-singlet (RS) phase and 5 other phases, FM, FM-Z, FM-XY, AF and AF-Z, with conventional long-range magnetic order. The 3 ferromagnetic phases, FM, FM-Z and FM-XY simultaneously have non-zero scalar chirality. Two other phases, the antiferromagnetic Gamma (AΓ) and ferromagnetic Gamma (FΓ) phases, have previously been observed in the Kitaev–Gamma ladder, demonstrating that the AΓ-phase is a symmetry protected topological phase (SPT) protected by TR ×Rb symmetry, the product of time-reversal (TR) and π rotation around the b-axis ( Rb ), while the FΓ-phase is related to the RS phase through a local unitary transformation. The 3 remaining phases, ϒ, Ω and δ show no conventional order, a doubling of the ES and for the ϒ and Ω-phases a gap is clearly present. The δ-phase has a significantly smaller gap and displays incommensurate correlations, with a peak in the static structure factor, S(k) continuously shifting from k/π=2/3 to k=π . In the Ω-phase we find pronounced edge-states consistent with a SPT phase protected by the same TR ×Rb symmetry as the AΓ-phase. The precise nature of the ϒ and δ-phases is less clear.

Cyclic and Isothermal Oxidation Behavior of a Directionally Solidified Ni-Al-Ti-Co-Cr Superalloy

Nickel based superalloys are widely used in such applications as gas turbine blades due to their excellent mechanical properties at elevated temperatures. Oxidation is one of the life limiting factors at such temperatures since it accelerates failure mechanisms, e.g. fatigue and creep. In this project, oxidation behavior of Ni-3Al-4.8Ti-9.5Co-14Cr (wt.%) superalloy was investigated under various testing conditions. The alloy was investment-cast with preferential crystal growth direction [100]. Isothermal oxidation tests were carried out at 800°C for 150h. Cyclic oxidation tests were then conducted between 100-800°C for 150 one-hour cycles. An additional one-hour cycle was tested to replicate real-life working condition of the alloy, which consisted of heating the samples up to 800°C followed by slow cooling to 400°C. During the testing, samples were periodically taken from the furnace and weighted with an accuracy of 10-4 g to calculate the weight gain and to analyze the microstructure of formed oxide. Scanning electron microscopy (SEM) combined with energy-dispersive spectroscopy (EDS) and X-ray diffraction were used to study the microstructure of oxidation products. The results reveal that the highest amount of weight gain is obtained in isothermal testing, while the lowest in cyclic. Diffusion of Ti and Ni to the free surface results in the early-stage formation of needle-shaped oxide phases followed by severe oxidation of Cr and Al. The layer of chromium oxide is continuous while aluminum oxide is blocky at the deepest position from the free surface. Cracks form at the interface of carbide particles and gamma phase near the free surface of cyclic oxidation samples due to concentration gradient of Ni and Al. Precipitate-free zone are observed near the free surface of all the samples at the end of the tests, but internal oxidation does not occur significantly in all the samples. It is found that temperature fluctuation increases oxide spallation, which causes crack formation. At the same time, in isothermal testing, dense, crack-free layer of oxide form on the surface of superalloy.

Supercritical CO2 mediated construction of aluminium waste recovered γ-Al2O3 impregnated Dracaena trifasciata biomass-derived carbon composite: A robust electrocatalyst for mutagenic pollutant detection

Inspired by the waste-to-wealth concept, we have recovered the gamma phase aluminium oxide nanoparticles (γ-Al2O3 NPs) from waste aluminium (Al) foils and fabricated a composite with Dracaena trifasciata biomass-derived activated carbon matrix (DT-AC) using supercritical carbon-di-oxide (SC-CO2) pathway. The prepared samples are characterized altogether by various micro- and spectroscopic analyses. Based on the results, the recovered γ-Al2O3 NPs are well impregnated in the DT-AC surface by the action of the microbubble effect from the SC-CO2. The higher D-band and ID/IG value of 1.07 in the Al2O3/DT-AC nanocomposite indicate increased defects and the amorphous nature of the carbon materials. The effect of scan rate (ν) demonstrated greater linearity in ν1/2 vs peak current in the electrochemical detection study of the mutagenic pollutant 4-(methylamino) phenol hemi sulfate, showing a quasi-reversible electron transfer process undergoing diffusion-controlled kinetics. Furthermore, the limit of detection is determined to be 3.2 nM L–1 with an extensive linear range, spanning from 0.05 to 618.25 µM/L. The incredible sensitivity of 2.117 μA μM−1 cm−2, along with excellent selectivity, repeatability, and stability, is observed. Further, the respectable recovery percentage of 98.61 % in the environmental water sample is perceived. The observed outcomes suggest that the prepared Al2O3/DT-AC composite performs as an excellent electrocatalyst material, and the processing techniques used are thought to be sustainable in nature.

Effect of Polyvinylpyrrolidone on the Structure Development, Electrical, Thermal, and Wetting Properties of Polyvinylidene Fluoride-Expanded Graphite Nanocomposites.

Polyvinylidene fluoride (PVDF)-expanded graphite (ExGr) nanocomposites have been prepared by solution blending and melt processing methods. In the presence of polyvinylpyrrolidone (PVP), enhanced dispersion of graphite nanosheets (GNSs) in the PVDF matrix, as suggested by field emission scanning electron microscopy analysis, results in very low electrical percolation threshold (0.3 wt % ExGr). X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry (DSC) analyses confirm the coexistence of electroactive gamma and nonpolar alpha phases. Wrapping of PVP chains around GNSs reduces the crystallinity in PVDF-ExGr nanocomposites in comparison to that in neat PVDF films, as evidenced by DSC analysis. Thermogravimetric analysis confirms enhanced thermal stability of PVDF-ExGr nanocomposites above 500 °C mainly attributed to the PVP-assisted dispersion of GNSs. The water contact angle of solution-blended PVDF-ExGr nanocomposite films increases with and without PVP in comparison to that of the neat PVDF film. Compression-molded PVDF-ExGr nanocomposites also exhibit electroactive gamma and nonpolar alpha phases of PVDF with reduction in electrical conductivity compared to solvent-cast films.

PREDICTION OF DEPTH OF NITRIDE LAYER IN IRON DURING GAS NITRIDING USING NEURAL NETWORK

Surface engineering of materials can add economic value to the material. Gas nitriding in iron is a typical thermochemical surface engineering process at eutectoid temperatures, where nitrogen diffuses to the surface to form nitride layers in the form of gamma phase and epsilon phase. In this study, a computational approach will be taken to predict the formation of the nitriding layer. In the prediction, a backpropagation neural network is used with input parameters of temperature, nitriding potential and time with an output of nitriding layer depth. This prediction does not distinguish the phase formed in the nitriding layer. The best results were obtained in the model of single hidden layer with 5 neurons and two hidden layers with the formation starting with 6 neurons followed by 5 neurons. The mean square error of the training data for the single hidden layer is 0.0027. While for two hidden layers the value is higher at 0.0032. The results obtained for the absolute mean error and root mean square values for the single hidden layer model are 0.6117 and 0.9670. For the two hidden layers model, the absolute error and root mean square values are 0.5894 and 1.0472. It can be seen from the correlation coefficient that both models can only predict well at depths of more than 10 μm.

How Do Event‐Related Gamma Oscillations Differ in Alzheimer’s Disease From Other Types of Dementia ?

AbstractBackgroundAlthough recent studies showed that gamma frequency entrainment might have therapeutic effects on Alzheimer’s Disease (AD) (Iaccarino et al. 2016), the gamma band abnormalities in AD patients are still poorly understood, while some studies presented increased gamma responses in AD, others showed reduced gamma responses (Güntekin et al., 2022). The differentiation of gamma responses between different dementia types is also not known. The present study aims to analyze the event‐related gamma responses in AD patients and to find out how the event‐related gamma responses differentiate between AD, Parkinson’s disease dementia (PDD), and Lewy Body dementia (DLB).MethodEEG of 17 DLB, 19 PDD, 20 AD patients, and 20 healthy controls was recorded with a 32‐channel EEG device. Subjects had performed visual oddball paradigm during EEG recordings. Event‐related phase locking and Event‐related power were analyzed in three gamma frequency bands (25‐30 Hz, 30‐35 Hz, 35‐48 Hz) in three different time windows (0 200 ms, 200 400 ms, 400‐600 ms) for target and non‐target stimuli. Repeated measures of ANOVA were used with the between‐subjects and within‐subjects factors.ResultTarget responses elicited higher gamma phase locking than the non‐target responses (p<0.05). Healthy subjects had higher gamma phase locking than AD, PDD, and DLB patients (p<0.05). The healthy control group had increased gamma power in the 0‐200 ms time window at frontal and central locations (p<0.05); however, patient groups did not have this early time window increase of gamma responses. Furthermore, although it was non‐significant, gamma phase locking values of PDD and DLB patients were worse than AD.ConclusionThe present study showed that AD, PDD, and DLB patients had reduced event‐related gamma phase locking and power in the early time window compared to healthy elderly controls. The gamma phase locking values of PDD and DLB patients were worse than those of AD patients. The present study showed that similar to AD patients and other dementia types could also have deficits in the gamma frequency band. Since the PDD and DLB patients had even more abnormal gamma band activities, the gamma entrainment could also have positive effects in these groups of patients.

Effect of silver and heat treatment on properties of 03Kh17N10M2 austenitic steel wire

The article examines the influence of various heat treatments, their temperature, as well as silver alloying on mechanical properties, phase composition and structure of steel wire from chromium-nickel-molybdenum austenitic stainless steel 03Kh17N10M2. Choice of the amount of silver alloying was based on previous studies of the antibacterial effect of modifying medical steels with silver. Since the antibacterial effect was confirmed on several bacterial strains, for the most efficient operation of alloys, it is necessary to determine the best temperature mode for working with them. Steel for the study was smelted and then transformed into wire through rolling, forging and drawing operations. On the obtained wire samples of different diameters with a silver content (0; 0.2 and 0.5 wt. %) mechanical tests were carried out to determine the elongation, yield strength and tensile strength. Various modes and temperatures of heat treatment were tested on wire of different diameters to study their effect on mechanical properties and structure. Microstructure of the wire samples subjected to heat treatment and obtained after drawing was investigated. A phase analysis was also carried out to determine the effect of silver in various quantities on austenitic steel. According to the results of the phase composition analysis, it was concluded that silver reduces the amount of gamma phase in steel, and this effect increases in proportion to the increase in silver amount. This change correlates with a slight drop in the metal ductility. At the same time, there are no significant changes in the strength characteristics and microstructure from the presence of silver.