GABA
receptors (GABA
Rs) play a crucial role in mammalian adult brain inhibition. The dysfunction of GABAergic drive is related to such disorders as epilepsy, schizophrenia, and depression. ...Substantial progress has recently been made in describing the static structure of GABA
Rs, but the molecular mechanisms that underlie the activation process remain elusive. The C loop of the GABA
R structure shows the largest movement upon ligand binding to the orthosteric binding site, a phenomenon that is referred to as "capping." The C loop is known to be involved in agonist binding, but its role in the gating of Cys-loop receptors is still debated. Herein, we investigated this issue by analyzing the impact of a β
F200 residue mutation of the C loop on gating properties of α
β
γ
GABA
Rs. Extensive analyses and the modeling of current responses to saturating agonist application demonstrated that this mutation strongly affected preactivation, opening, closing and desensitization, i.e. all considered gating steps. Single-channel analysis revealed that the β
F200 mutation slowed all shut time components, and open times were shortened. Model fitting of these single-channel data further confirmed that the β
F200 mutation strongly affected all of the gating characteristics. We also found that this mutation altered receptor sensitivity to the benzodiazepine flurazepam, which was attributable to a change in preactivation kinetics. In silico analysis indicated that the β
F200 mutation resulted in distortion of the C loop structure, causing the movement of its tip from the binding site. Altogether, we provide the first evidence that C loop critically controls GABA
R gating.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study showed that a polylactide (PLA)-based composite filled with nanostructured hydroxyapatite (HAp) and a natural extract from the rhizome of Curcuma longa L. could provide an alternative to ...commonly used fossil-based plasticsfor food packaging. The incorporation of HAp into the PLA matrix had a positive effect on improving selected properties of the composites; the beneficial effect could be enhanced by introducing a green modifier in the form of an extract. Prior to the fabrication of the composite, the filler was characterized in terms of morphology and composition, and the composite was then fully characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman and Fourier transform infrared spectroscopy (FT-IR), and the mechanical, thermal, thermomechanical, and optical properties were investigated. The proposed material exhibits antioxidant properties against DPPH radicals and antibacterial performance against Escherichia coli (E. coli). The results showed that the nanocomposite has the highest antioxidant and antibacterial properties for 10 wt% HAp with an average diameter of rod-shaped structures below 100 nm. In addition, the introduction of turmeric extract had a positive effect on the tensile strength of the nanocomposites containing 1 and 5% HAp. As the resulting material adsorbs light in a specific wavelength range, it can be used in the medical sector, food-packaging, or coatings.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Developing highly efficient and cost‐effective electrocatalysts for oxygen reduction reaction (ORR) in aqueous media is crucial for energy conversion systems such as fuel cells or Zn‐air batteries. ...Electrode materials from spent devices such as lithium‐ion batteries (LiBs) are a serious environmental problem. One of the solutions is their reuse for other electrochemical processes. This work demonstrates the application of solid residues of carbon‐based powders left over from the hydrometallurgical recycling process of LIBs’ waste as efficient catalysts for ORR. Microscopic and spectroscopic studies of the residue disclosed their porous structure and various cobalt contents, depending on the recycling procedure. These battery wastes display ORR catalytic activity when deposited at the liquid‐liquid and solid electrode‐electrolyte interfaces. Scanning Electrochemical Microscopy (SECM) tests showed that assembling battery waste at the liquid‐liquid interface boosts the efficiency of H2O2 production by one to two orders of magnitude. The catalytic activity towards 2‐electron ORR strongly depends on waste powder compositions and structures, e.g., porosity, heteroatom presence, level of defects, and graphitization.
This paper demonstrates the utilization of Li‐ion battery waste as an efficient electrocatalyst for ORR. The studies show that the waste powder compositions and structures, e. g., porosity, heteroatom presence, level of defects, and graphitization, have a significant impact on its catalytic activity towards 2‐electron ORR.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The skin properties, structure, and performance can be influenced by many internal and external factors, such as age, gender, lifestyle, skin diseases, and a hydration level that can vary in relation ...to the environment. The aim of this work was to demonstrate the multifaceted influence of water on human skin through a combination of in vivo confocal Raman spectroscopy and images of volar-forearm skin captured with the laser scanning confocal microscopy. By means of this pilot study, the authors have both qualitatively and quantitatively studied the influence of changing the depth-dependent hydration level of the stratum corneum (SC) on the real contact area, surface roughness, and the dimensions of the primary lines and presented a new method for characterizing the contact area for different states of the skin. The hydration level of the skin and the thickness of the SC increased significantly due to uptake of moisture derived from liquid water or, to a much lesser extent, from humidity present in the environment. Hydrated skin was smoother and exhibited higher real contact area values. The highest rates of water uptake were observed for the upper few micrometers of skin and for short exposure times.
The present study of Knautia drymeia and K. macedonica is in line with the current trend of searching for new plant species that can potentially be used as medicinal herb materials. A comparative ...analysis of the morphological and anatomical structure of both species was performed together with the distribution of polyphenolic compounds, which was correlated with the tissue structure of plant organs. Quantitative phytochemical analyses were performed to supplement the biophysical analyses. Both species had a similar morphological, anatomical, and histological structure. Polyphenolic compounds were accumulated in the parenchyma tissue in an organ-specific mode, mainly in the leaves. The phytochemical analyses revealed organ- and species-dependent variations in the polyphenol content. Thus, the highest polyphenol amount was observed in the leaves, with equal levels of total polyphenols and phenolic acids in the leaves of K. macedonica and K. drymeia, respectively. The present study integrates morphological/histological analyses with investigations of the biotechnological/pharmaceutical potential of the studied plants and constitutes an innovative and holistic approach to the current research problem.
The marine microplastic (MMs) is an interdisciplinary problem. The polymer debris are ubiquitous (soil, hydrosphere, atmosphere) and the majority ends, transported by the freshwaters, in the global ...ocean system: from pelagial waters, surface gyres and benthos up to the animals at different trophic levels. Their quantitative, qualitative and eco-toxicological analyses, based on analytical, physical and chemical methods, are still a challenge due to the complex matrices, materials weathering, limited concentration, and size. Moreover, further fragmentation due to the waves and UV radiation leads to the constant increase of their surface. The aim of this article is to present the advantages, drawbacks and future perspectives of using SEM-EDX method in the analyses of marine polymer debris from macro to the nanoscale. Theoretical issues are presented in comparison to the commonly used approaches. The practical aspects will be discussed based on case studies. Examples of the results, high-resolution SEM pictures are included.
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•Article addresses the problem of characterisation of ubiquitous microplastic debris.•SEM-EDX method applicability to MMs discussed in comparison to other techniques•The efficient and simpler than the currently-used approach to MMs analysis by SEM-EDX•The introduction to the rising complex problem of nanoplastics•Practical conclusions from case studies
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The horticultural cultivars of
(daylily) have been used to treat diseases such as insomnia, inflammation and depression, and also as a vegetable in eastern Asia. Taking into consideration the fact, ...that the volatile compounds in
cultivars have not been investigated to date, we decided to study the composition of the essential oils (EOs) from the aerial parts of ten varieties collecting in Poland. EOs, obtained by hydrodistillation, were analyzed by GC/MS method that resulted in identification of 23-36 volatile compounds comprising 89.5%–96.3% of the total amount. The essential oils differed in their composition and they can be classified into three groups. The antibacterial and antioxidant activities of EOs were also evaluated. Gram-negative strains were most strongly inhibited by all tested oils. Two model systems have been used for the antioxidant efficacy, 2,2-diphenyl-1-picryl-hydrazyl (DPPH•) andβ-carotene bleaching assays. The essential oils with the high presence of oxygenated monoterpenes and monoterpene hydrocarbons showed higher antioxidant activity. The chemical composition of EOs of
cultivars and their biological activity is reported for the first time. Thus, the findings presented here suggest that the aerial parts of
cultivars may be candidates for the development of new phytomedicine.
In this work, we investigated the potential of pristine biochar (obtained from poultry manure by pyrolysis at 725°C in a laboratory pyrolysis reactor under N2 environment) as an efficient adsorbent ...for removing tetracycline (TC) and rhodamine 6G (R6G) from aqueous solutions. Microscopic and spectroscopic analyses demonstrated a developed surface of the investigated biochar free from toxic organic compounds that could form within the annealing. The removal of TC and R6G was analyzed with UV-vis spectrometry in the function of the pH, ionic strength, and adsorbent dosage. The maximal adsorption capacity for TC and R6G is 65 and 63 mg g–1, respectively, indicating that pristine biochar from poultry manure has an excellent adsorption ability for both compounds demonstrating its high potential for removing various compounds of this type from water media. The enhanced adsorption on the investigated biochar is mainly controlled by the strong π–π and n–π interactions between the surface of the biochar and the two contaminants. The investigated poultry manure derived biochar can be a promising “green”, sustainable and carbon-rich material for low-cost and facile environmental applications, including the removal of contaminants from municipal wastewater.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aimed to investigate changes in the elasticity of the median and ulnar nerves in cyclists.
The study included 30 cyclists and 2 non-biking reference groups that included 32 healthy ...volunteers and 32 individuals with ulnar nerve entrapment neuropathies. All participants underwent physical, ultrasonographic, and elastographic examinations including assessment of nerve cross-sectional area (CSA) and stiffness (SWE). The cyclists' group was tested before and after a 2-hour workout.
The values of ulnar nerve CSA and stiffness in Guyon's canal in resting cyclists were 5.30 ± 1.51 mm
and 49.05 ± 11.18 kPa, respectively. These values were significantly higher than in the healthy volunteers, but not higher than in the nerve entrapment group. Median nerve CSA and stiffness at rest were 9.10 ± 2.61 mm
and 38.54 ± 14.87 kPa, respectively. Both values were higher than respective values in the healthy group. Cycling induced an increase in all these parameters, although the increase in nerve stiffness was more noticeable than in CSA.
The elasticity of the median and ulnar nerve in cyclists remains within normal limits, questioning the belief that cyclists are at risk of nerve palsy in Guyon's canal. However, cycling workout does exert compression, resulting in transient oedema of both nerves. The dynamics of changes was more noticeable in SWE examination than in conventional ultrasound, which may depend on SWE sensitivity.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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