Search Results (278)

One major challenge in cellular neuroscience is to elucidate how the accurate alignment of presynaptic release sites with postsynaptic densely clustered ligand-gated ion channels at chemical synapses is achieved upon synapse assembly. The clustering of neurotransmitter receptors at postsynaptic sites is a key moment of synaptogenesis and determinant for effective synaptic transmission. The number of the ionotropic neurotransmitter receptors at these postsynaptic sites of both excitatory and inhibitory synapses is variable and is regulated by different mechanisms, thus allowing the modulation of synaptic strength, which is essential to tune neuronal network activity. Several well-regulated processes seem to be involved, including lateral diffusion within the plasma membrane and local anchoring as well as receptor endocytosis and recycling. The molecular mechanisms implicated are numerous and were reviewed recently in great detail. The role of pre-synaptically released neurotransmitters within the complex regulatory apparatus organizing the postsynaptic site underneath presynaptic terminals is not completely understood, even less for inhibitory synapses. In this mini review article, we focus on this aspect of synapse formation, summarizing and contrasting findings on the functional role of the neurotransmitters glycine and γ-aminobutyric acid (GABA) for initiation of postsynaptic receptor clustering and regulation of Cl⁻ channel receptor numbers at inhibitory synapses gathered over the last two decades. Full article

Anoplophora glabripennis, is one of the most devastating wood borers of many broad leaf trees. Our previous results indicated that antennae of A. glabripennis showed electroantennogram (EAG) responses to several host plant volatiles. However, the quantities of active compounds necessary to trigger an EAG response remains unclear. To relate EAG responses with quantities of active molecules, we quantified the level of molecular triggering in the EAG response of A. glabripennis by a series of procedures. First, we used the EAG apparatus to measure EAG responses of A. glabripennis to five concentrations of eight chemicals and obtained dose–response curves. Second, volatiles released after blowing air over filter paper loaded with volatiles for different numbers of times (purging) were collected by solid-phase microextraction (SPME) and quantified by gas chromatography (GC), so we obtained the quantity of chemical released from each purge; the minimum number of molecules in each purge in the EAG was calculated by the molar mass for different compounds. For instance, the number of molecules of (Z)-3-hexenol reaching the female antennal segment in EAG was 8.68 × 10⁸ at 0.01 ng/μL concentration, and 1.39 × 10⁵ at 0.01 mV potential value. Finally, by comparing sensilla numbers on tested antennal segments with the entire antennae, the minimum number of molecules, or molecular flow, of tested compounds required to elicit an electrophysiological response from two antennae of ALB could be estimated either at a minimum concentration (2.49 × 10⁸ at 0.01 ng/μL concentration of (Z)-3-Hexenol, for female) or at a minimum potentiometric response value (3.99 × 10⁴ at 0.01 mV potential value). Full article

The vast majority of viruses causing human and animal diseases are enveloped—their virions contain an outer lipid bilayer originating from a host cell. Small molecule antivirals targeting the lipid bilayer cover the broadest spectrum of viruses. In this context, we consider the chemical nature and mechanisms of action of membrane-targeting antivirals. They can affect virions by (1) physically modulating membrane properties to inhibit fusion of the viral envelope with the cell membrane, (2) physically affecting envelope lipids and proteins leading to membrane damage, pore formation and lysis, (3) causing photochemical damage of unsaturated membrane lipids resulting in integrity loss and fusion arrest. Other membrane-active compounds can target host cell membranes involved in virion’s maturation, coating, and egress (endoplasmic reticulum, Golgi apparatus, and outer membrane) affecting these last stages of viral reproduction. Both virion- and host-targeting membrane-active molecules are promising concepts for broad-spectrum antivirals. A panel of approved antivirals would be a superior weapon to respond to and control emerging disease outbreaks caused by new viral strains and variants. Full article

This work presents a comparative analysis of the results of silicon carbide synthesis through the carbonization of Si (001) and Si (111) substrates in the temperature range 1130–1140 °C. The synthesis involved chemical vapor deposition utilizing thermally stimulated methane reduction in a hydrogen gas stream. The experiments employed an Oxford Nanofab Plasmalab System 100 apparatus on substrates from which the native oxide was removed according to established protocols. To minimize random experimental variations (e.g., deviations from set parameters), short synthesis durations of 3 and 5 min were analyzed. The resultant thin films underwent evaluations through several techniques, including X-ray photoelectron spectroscopy, X-ray diffractometry, optical emission spectroscopy with glow discharge, and transmission electron microscopy. A comparison and analysis were conducted between the results from both substrate orientations. Full article

Tocopherols, due to their antioxidant properties, are valuable compounds in the food and pharmaceutical industries. The present study compares the glyceride oil content and tocopherol profile of seeds of 49 plant species from 39 families of Bulgarian wild flora to identify their potential industrial and nutritional applications. The oils were extracted using the Soxhlet apparatus, and the tocopherol and tocotrienol composition was established by high-performance liquid chromatography (HPLC). Hierarchical cluster analysis was performed to group the plants based on their tocopherol profile. The results show high variability in the content of glyceride oils (ranging from 0.5% to 40.6%) and tocopherol profiles among species, even among plants within the same family. Four clusters were identified, each of which was characterized by the dominance of one of the tocopherol or tocotrienol isomers, i.e., α-tocopherol or γ-tocopherol, and reflected the chemical diversity of the examined plants. The statistical analysis confirmed that tocopherols and tocotrienols are significant factors influencing cluster grouping. The results reflect natural variability among species grown under field conditions, influenced by both genetic and environmental factors. This study provides valuable preliminary information for identifying wild species with promising tocopherol profiles for future functional research. Full article

Magnetic field (MF) priming provides a chemical-free alternative to conventional methods; however, static exposure approaches are often limited by spatial heterogeneity in field–seed interaction caused by fixed seed positioning, undermining both treatment uniformity and reproducibility. To address this, the present study investigated the effects of dynamic MF exposure on the germination and early growth of Khao Dawk Mali 105 (KDML 105) rice seeds. A novel MF testing apparatus was developed using a 150 mT permanent magnet and a vortex-based air injection system designed to continuously rotate and redistribute seeds, ensuring uniform exposure. Seeds were treated for 0, 5, 10, 15, and 20 min to evaluate effects on vigor, germination, and seedling growth. The results showed that 5 and 10 min exposures significantly enhanced seed vigor (93.00% and 94.67%, respectively) compared to the control (83.33%), with 10 min yielding the highest improvement (p < 0.05, DMRT). Shoot and root growth also increased by 14.21% and 99.59%, respectively. These findings suggest that moderate-duration dynamic MF exposure is an efficient, eco-friendly priming technique for improving seed vigor and early growth. Future research should explore long-term agronomic impacts, economic feasibility, and varietal responses. The apparatus’s scalable design supports integration into industrial seed processing lines, advancing sustainable rice production. Full article

This study presents a comparative analysis of the water droplet erosion resistance of three compressor wheels coated with Ni-P and Si-P layers. The tests were conducted using a custom-developed experimental apparatus in accordance with the ASTM G73-10 standard. The degree of erosion was monitored through continuous precision mass measurements, and structural changes on the surfaces of both the base materials and the coatings were examined using a Zeiss Crossbeam 350 scanning electron microscope (SEM). Hardness values were determined using a Vickers KB 30 hardness tester, while the chemical composition was analysed using a WAS Foundry Master optical emission spectrometer. Significant differences in erosion resistance were observed among the various compressor wheels, which can be attributed to differences in coating hardness values, as well as to the detachment of the Ni-P layer from the base material under continuous erosion. In all cases, water droplet erosion led to a reduction in the isentropic efficiency of the compressor—measured using a hot gas turbocharger testbench—with the extent of efficiency loss depending upon the type of coating applied. Although blade protection technologies for turbocharger compressor impellers used in the automotive industry have been the subject of only a limited number of studies, modern technologies, such as the application of certain alternative fuels and exhaust gas recirculation, have increased water droplet formation, thereby accelerating the erosion rate of the impeller. The aim of this study is to evaluate the resistance of three different coating layers to water droplet erosion through standardized tests conducted using a custom-designed experimental apparatus. Full article

Background/Objectives: A material incompatibility has been established between self-etching adhesives and amine-containing dual-cure resin composite materials used for core buildups. This study aims to compare the dentin bond strength of several amine-containing and amine-free core materials using self-etching adhesives with different pHs. Methods: Extracted human molars were mounted in acrylic and ground flat with 320-grit silicon carbide paper. Next, 520 specimens (n = 10/group) were assigned to a dual-cure core buildup material group (10 amine-containing, 2 amine-free, and 1 reference light-cure only bulk fill flowable composite) and assigned to a self-etching adhesive subgroup (pH levels of approximately 1.0, 3.0, and 4.0). Within 4 h of surface preparation, the adhesive corresponding to the specimen’s subgroup was applied and light-cured. Composite buttons for the assigned dual-cure core material of each group were placed using a bonding clamp apparatus, allowed to self-cure for 2 h at 37 °C, and then unclamped. An additional group with one adhesive (pH = 3.0) was prepared in which the dual-cure core materials were light-cured. The bonded specimens were stored in water at 37 °C for 24 h. The specimens were mounted on a testing clamp and de-bonded in a universal testing machine with a load applied to a circular notched-edge blade at a crosshead speed of 1 mm/min until bond failure. The maximum load divided by the area of the button was recorded as the shear bond strength. The data was analyzed via 2-way ANOVA. Results: The analysis of bond strength via 2-way ANOVA determined statistically significant differences between the adhesives, the core materials, and their interaction (p < 0.01). There was a general trend in shear bond strength for the adhesives, where pH 4.0 > 3.0 > 1.0. The amine-free core materials consistently demonstrated higher shear bond strengths as compared to the other core materials when chemically cured only. Light-curing improved bond strength for some materials with perceived incompatibility. Conclusions: The results of this study suggest that an incompatibility can exist between self-etching adhesives and dual-cure resin composite core materials. A decrease in the pH of the utilized adhesive corresponded to a decrease in the bond strength of dual-cure core materials when self-curing. This incompatibility may be minimized with the use of core materials formulated with amine-free chemistry. Alternatively, the dual-cure core materials may be light-cured. Full article

The objective of this study is to explore the high-temperature rheological properties and microscopic interaction mechanisms of styrene–butadiene–styrene (SBS) composite-modified asphalt with hydroxylated multi-walled carbon nanotubes (MWCNT-OH). SBS-modified asphalt, MWCNT-modified asphalt and MWCNT/SBS composite-modified asphalt were prepared with high-speed shearing apparatus and machine mixer. Physical property tests, dynamic shear rheological (DSR) tests, multiple stress creep recovery (MSCR) tests, X-ray diffraction (XRD) and Raman spectroscopy analyses were carried out to systematically compare the differences in macroscopic performance and changes in microscopic structure of different types of asphalts. According to the results of physical property tests, DSR tests and MSCR tests, the composite-modified asphalt was superior to the single-component-modified asphalt in terms of complex modulus (G*) and rutting factor (G*/sin δ). Its creep recovery rate (R) and unrecoverable compliance (Jnr) exhibited better anti-deformation ability under high temperatures, verifying the synergistic effect of SBS and MWCNTs-OH. XRD analysis showed that composite modification reduced the disorder degree of the crystalline phase of asphalt. Raman spectroscopy confirmed that there were changes in the vibration of chemical bonds between the modifier and asphalt, indicating that the modifier and asphalt acted on the asphalt system through physical dispersion and chemical cross-linking. Full article

Cellular stressors have been demonstrated to exert a substantial influence on the functionality of organelles, thereby impacting cellular homeostasis and contributing to the development of disease pathogenesis. This review aims to examine the impact of diverse stressors, including environmental, chemical, biological, and physical factors, on critical organelles such as the cell membrane, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and membrane-less organelles. The intricate molecular mechanisms underlying cellular stress responses, encompassing oxidative stress, protein misfolding, and metabolic reprogramming, have the capacity to elicit adaptive responses or culminate in pathological conditions. The interplay between these stressors and organelle dysfunction has been implicated in a myriad of diseases, including neurodegenerative disorders, cancer, metabolic disorders, and immune-related pathologies. A comprehensive understanding of the mechanisms by which organelles respond to stress can offer valuable insights into the development of therapeutic strategies aimed at mitigating cellular damage. Full article

The increasing demand for high-performance materials has led to an increase in the use of carbon fibre-reinforced plastics (CFRPs) in recent decades, increasing the waste from end-of-life materials and off-cuts. The recycling of CFRPs, especially when thermosetting matrices are used, still remains an open challenge for academia and industry, with chemical, thermal and mechanical strategies being explored. Among them, mechanical methods have garnered growing interest since they do not require high specific energy consumption or expensive apparatus. However, from the literature it was observed that when using these methods, traces of old matrix remain on the fibre’s surface, compromising the fibre–matrix adhesion efficiency and limiting their use in recycled composites. On the other hand, solvothermal methods are known for their high matrix dissolution efficiency that in turn improves the fibre–matrix adhesion. Therefore, in this paper, end-of-life CFRPs from the aeronautic sector were machined using a milling-based mechanical recycling method, while to remove the residual matrix from the fibre surface, the recovered chips were chemically treated with a two-step treatment at low temperature. Then, two types of recycled composite laminates were manufactured using the compression moulding technique: the first using recycled fibres only from the mechanical recycled method, and the second one using recycled fibres deriving from both recycling methods. The feasibility of the process was analysed observing that the additional chemical treatment led to a mass loss of almost 24% in the recycled fibres. FTIR analysis revealed the complete matrix dissolution since no spectra of epoxy resin groups were detected. Finally, the flexural behaviour of the recycled composites was investigated, revealing an increase in the flexural strength and modulus of the second sample typology, respectively, of almost 42% and 76% thanks to the improved fibre–matrix adhesion as a consequence of the solvothermal treatment. Full article

Enhancing the growth and productivity of ornamental and horticultural plants is a major function of plant extracts and macronutrient elements. The growth properties of Artemisia abrotanum plants were evaluated in two successive seasons as affected by the magnesium (Mg) fertilizer added to the soil in the form of magnesium sulfate at four concentrations of 0 (as a control), 4, 6, and 8 g/L as well as Tropaeolum majus aqueous leaf extract (ALE) at concentrations of 0 (as a control), 4, 6, and 8 g/L as a foliar application. The chemical components of A. abrotanum essential oils (EOs) were analyzed using the gas chromatography–mass spectrometry (GC-MS) apparatus. The studied parameters, including plant height, total fresh weight, number of branches/plant, EO percentages, chlorophyll-a content, chlorophyll-b content, and carotenoid content, were enhanced by the application of Mg or T. majus ALE or their combinations. The highest plant heights, 48.83 cm, and 48.5 cm, were observed in the plants treated with Mg (8 g/L)+T. majus ALE (8 g/L) and Mg (6 g/L)+T. majus ALE (4 g/L), in both seasons, respectively. The highest values of total fresh weight, 54.80 and 60.59 g, were recorded in plants treated with Mg (8 g/L)+T. majus ALE (4 g/L) and Mg (8 g/L)+T. majus ALE (4 g/L), in both seasons, respectively. The highest number of branches/plant, 60.33 and 73.33, were measured in plants treated with Mg (8 g/L)+T. majus LAE (8 g/L), in both seasons, respectively. The highest EO percentages, 0.477% and 0.64%, were measured in plants treated with Mg (8 g/L)+T. majus ALE (8 g/L), in both seasons, respectively. The total fresh weight in both seasons (r = 0.96), the number of branches/plant in both seasons (r = 0.97), the number of branches/plant in the first season, and the number of branches/plant in both seasons (r = 0.96), the total fresh weight in the second season and the number of branches/plant in the first season (r = 0.95) and the second season (r = 0.94), and the number of branches/plant and the carotenoids in the first season (r = 0.90) were all found to be significantly and positively correlated. The major compounds in the EOs were 7-methoxy-4-methylcoumarin (4-methylherniarin), cedrol, endo-borneol, and 7-epi-silphiperfol-5-ene. The antibacterial activity of the EOs was evaluated against the growth of Pectobacterium atrosepticum and Pectobacterium carotovorum subsp. carotovorum, which causes soft rot of potato tubers. The EOs were found to be effective against P. carotovorum subsp. carotovorum with the inhibition zones ranging from 1 to 5 mm at the concentration of 100 μg/mL, and no inhibitions were found against P. atrosepticum at the studied concentrations. The minimum inhibitory concentration against P. carotovorum subsp. carotovorum was found at 75 μg/mL. In conclusion, using the combination treatments of Mg and T. majus ALE is highly suggested to enhance the growth of A. abrotanum plants. Full article

Sensory signals generated by peripheral nociceptors are transmitted by peptidergic and nonpeptidergic nociceptive primary afferents to the superficial spinal dorsal horn, where their central axon terminals establish synaptic contacts with secondary sensory spinal neurons. In the case of suprathreshold activation, the axon terminals release glutamate into the synaptic cleft and stimulate postsynaptic spinal neurons by activating glutamate receptors located on the postsynaptic membrane. When overexcitation is evoked by peripheral inflammation, neuropathy or pruritogens, peptidergic nociceptive axon terminals may corelease various neuropeptides, neurotrophins and endomorphin, together with glutamate. However, in contrast to glutamate, neuropeptides, neurotrophins and endomorphin are released extrasynaptically. They diffuse from the site of release and modulate the function of spinal neurons via volume transmission, activating specific extrasynaptic receptors. Thus, the released neuropeptides, neurotrophins and endomorphin may evoke excitation, disinhibition or inhibition in various spinal neuronal populations, and together with glutamate, induce overall overexcitation, called central sensitization. In addition, the synaptic and extrasynaptic release of neurotransmitters is subjected to strong retrograde control mediated by various retrogradely acting transmitters, messengers, and their presynaptic receptors. Moreover, the composition of this complex chemical apparatus is heavily dependent on the actual patterns of nociceptive primary afferent activation in the periphery. This review provides an overview of the complexity of this signaling apparatus, how nociceptive primary afferents can activate secondary sensory spinal neurons via synaptic and volume transmission in the superficial spinal dorsal horn, and how these events can be controlled by presynaptic mechanisms. Full article

Iron-based oxygen carriers (OCs) have received much attention due to their low costs, high mechanical strengths and high-temperature stabilities in the chemical looping gasification (CLG) of biomass, but their chemical reactivity is very ordinary. Converter steel slags (CSSs) are steelmaking wastes and rich in Fe₂O₃, CaO and MgO, which have good oxidative ability and good stability as well as catalytic effects on biomass gasification. Therefore, the composite OCs prepared by mechanically mixing CSSs with iron-based OCs are expected to be used to increase the hydrogen production in the CLG of biomass. In this study, the catalytic performance of CSS/Fe₂O₃ composite OCs prepared by mechanically mixing CSSs with iron-based OCs on the gasification of brewers’ spent grains (BSGs) were investigated in a tubular furnace experimental apparatus. The results showed that when the weight ratio of the CSSs in composite OCs was 0.5, the relative volume fraction of hydrogen reached the maximum value of 49.1%, the product gas yield was 0.85 Nm³/kg and the gasification efficiency was 64.05%. It could be found by X-ray diffraction patterns and scanning electron microscope characterizations that the addition of CSSs helped to form MgFe₂O₄, which are efficient catalysts for H₂ production. Owing to the large and widely distributed surface pores of CSSs, mixing them with iron-based OCs was beneficial for catalytic steam reforming to produce hydrogen. Full article

This study focused on Atlas pistachio (Pistacia atlantica subsp. atlantica), an endangered species from the Moroccan Middle Atlas, analyzing its leaves to assess their antioxidant and antimicrobial activity. Essential oils (EOPA) were extracted by distillation using a Clevenger apparatus, and their phytochemical compounds were identified by gas chromatography–mass spectrometry (GC/MS). Antioxidant activity tests were carried out using the DPPH and FRAP methods. In addition, antimicrobial activity was tested against Candida albicans to determine its antifungal effect, and against two Gram-positive strains (Staphylococcus aureus and Bacillus subtilis) and three Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) to determine the antibacterial effect. The results show that the essential oils contained between 23 and 49 compounds, depending on the extraction area, with (-)-germacrene D as the main compound. Antioxidant activity varied by study area, with IC₅₀ ranging from 0.414 mg/mL (Amghas) to 1.520 mg/mL (Ait Naamane), and EC₅₀ from 2.132 mg/mL to 5.4 mg/mL. In terms of antimicrobial activity, Afourgah essential oils showed the best results, with significant inhibition diameters against bacteria and low MIC. In particular, Amghas essential oils inhibited Staphylococcus aureus well, while Ait Naamane essential oils were less effective. This variability in phytochemical composition, as well as antioxidant and antimicrobial activities, may be attributed to climatic differences specific to the distribution zones of the Atlas pistachio tree. This study contributes to a better understanding of the botanical and chemical characterization of the Pistacia genus, and highlights its potential as a source of bioactive agents. Full article