We study the energy landscape of the negatively charged protein bovine serum albumin adsorbed on a negatively charged silica surface at pH 7. We use fully atomistic molecular dynamics (MD) and ...steered MD (SMD) to probe the energy of adsorption and the pathway for the surface diffusion of the protein and its associated activation energy. We find an adsorption energy ∼1.2 eV, which implies that adsorption is irreversible even on experimental time scales of hours. In contrast, the activation energy for surface diffusion is ∼0.4 eV so that it is observable on the MD simulation time scale of 100 ns. This analysis paves the way for a more detailed understanding of how a protein layer forms on biomaterial surfaces, even when the protein and surface share the same electrical polarity.
The numerus clausus of property rights indicates that a mandatory closed catalogue of property rights exists in a given legal system; the content (method of creation, conveyance, expiration) of a ...right falling within this closed list is strictly specified and cannot be changed by the parties. In this way, the state consciously limits the activity of the parties in this regard, indicating the socially and legally acceptable types of property rights they can use. An insightful look at the development and explanation of this principle over the centuries and now seems to be necessary with the advancing unification of private law in Europe. The present article discusses the dogmatic basis of the concept of numerus clausus and outlines its history and economic reasoning behind it. Then, the main models of the numerus clausus in European legal orders as well as the functioning of this principle in Polish property law are presented. Subsequently, the strengths and weaknesses of the numerus clausus are examined. This provides us with general conclusions concerning the harmonization of this area of private law.
Tremor is one of the motor symptoms of Parkinson’s disease (PD), present also in neuroleptic-induced parkinsonism. Tremulous Jaw Movements (TJMs) are suggested to be a well-validated rodent model of ...PD resting tremor. TJMs can be induced by typical antipsychotics and are known to be reduced by different drugs, including adenosine A2A receptor antagonists. The aim of the present study was to search for brain structures involved in the tremorolytic action of SCH58261, a selective A2A receptor antagonist, in TJMs induced by subchronic pimozide. Besides TJMs, we evaluated in the same animals the expression of zif-268 mRNA (neuronal responsiveness marker), and mRNA levels for glutamic acid decarboxylase 65-kDa isoform (GAD65) and vesicular glutamate transporters 1 and 2 (vGluT1/2) in selected brain structures, as markers of GABAergic and glutamatergic neurons, respectively. We found that SCH58261 reduced the pimozide-induced TJMs. Pimozide increased the zif-268 mRNA level in the striatum, nucleus accumbens (NAc) core, and substantia nigra pars reticulata (SNr). Additionally, it increased GAD65 mRNA in the striatum and SNr, and vGluT2 mRNA levels in the subthalamic nucleus (STN). A positive correlation between zif-268, GAD65 and vGluT2 mRNAs and TJMs was found. SCH58261 reversed the pimozide-increased zif-268 mRNA in the striatum and NAc core and GAD65 mRNA in the striatum and SNr. In contrast, SCH58261 did not influence vGluT2 mRNA in STN. The present study suggests an importance of the striato-subthalamo-nigro-thalamic circuit in neuroleptic-induced TJMs. The tremorolytic effect of A2A receptor blockade seems to involve this circuit bypassing, however, STN.
•Blockade of adenosine A2A receptors by SCH58261 inhibits pimozide-induced TJMs.•Pimozide-induced tremor involves the striatum, subthalamus and substantia nigra.•SCH58261 reduced pimozide-induced striatal zif-268 and GAD65, and nigral GAD65 mRNAs.•Tremorolytic effects of SCH58261 involve striatum and substantia nigra but bypass subthalamus.
The S-(4-pentylphenyl) 4-(pentyloxy)benzothioate, forming the nematic phase, is investigated by X-ray diffraction in temperatures between 263 K and 365 K, with the support of differential scanning ...calorimetry and polarizing optical microscopy. The microscopic observations show changes within the solid state, while X-ray diffraction does not indicate any transitions between the crystal phases. The Rietveld refinement shows that the crystal phase formed from the melt is the same monoclinic crystal phase with the P21/c space group as reported for a single crystal grown from an ethanol solution. The temperature dependence of the unit cell parameters in the 263–335 K range is determined and the coefficients of thermal expansion are obtained. The unit cell expands on heating along the longer ac-diagonal and b-axis while, along the shorter ac-diagonal, a very small shrinkage occurs. The diffraction patterns of the liquid crystalline nematic phase indicate the formation of dimers via hydrogen bonding. Density functional theory calculations (def2TZVPP basis set, B3LYP-D3(BJ) correlation-exchange functional) are applied for geometry optimization of an isolated molecule and selected dimers.
The nature of the SmA*-SmC* phase transition was studied in three chiral liquid crystal compounds, in two belonging to the same homologous series, ...(S)-1-methylheptyl-4-(4′-alkoxybiphenylthiocarboxy)-benzoates, (S)-MHPSBOn, where n = 7 and 8 is the number of carbon atoms in the alkyl chain and (S)-4-(4-{1-methylheptylcarboxyl} phenyl) carbonylthio phenyl-4′-decyloxy-1-benzenecarboxylate (10OPOSMH). Compounds (S)-MHPSBO7 and (S)-MHPSBO8 show different behavior in the SmA*-SmC* phase transition, in MHPSBO7 the SmA* phase is the de Vries phase, while in MHPSBO8 it is the classic SmA* phase. The aim of the study is to demonstrate the presence of the de Vries type SmA * phase in three chiral thiobenzoates. The electro-optical method and SAXS were used to analyze the SmA*-SmC* transition.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Energy self-sufficiency is a current trend in wastewater treatment plants. This effect can be achieved by increasing the production of electricity from biogas and by reducing energy consumption for ...technological processes. One idea, in line with the circular economy concept, is the use of waste rich in organic matter as co-substrates for the fermentation process. The aim of this study was to determine the effect of waste co-fermentation on biogas production and nitrogen concentration in the reject water. A co-fermentation process with flotate or flotate and vegetables increased biogas production compared to primary sludge by 162 and 180%, respectively. During the tests, there was no inhibition of the fermentation process. Hydrolysis of organic compounds contained in flotate and vegetables resulted in a significant increase in ammonium nitrogen (by 80–100%) and dissolved organic nitrogen concentration (by 170–180%). The biogas and methane production rate as well as the ammonium and total nitrogen release rate were calculated. An energy balance was made, which took into account the variable amount of electric energy production depending on the efficiency of the cogeneration systems and energy consumption for supplying oxygen necessary to remove nitrogen contained in the reject water. A positive energy balance was obtained for all analyses.
The growing demand for implants has seen increasing interest in the introduction of new technologies and surface modification methods of metal biomaterials. This research aimed to produce and ...characterize a porous layer grown on austenitic stainless steel 316L, obtained via the anodization process near the micro-arc oxidation, i.e., low voltage micro-arc oxidation (LVMAO). The discussed layer significantly influences the properties of metallic biomedical materials. The surface topography, layer thickness, surface roughness, pore diameter, elemental composition, crystal structure, and surface wettability were assessed for all anodized layers, together with the resultant corrosion resistance. Attention was paid to the influence of the process parameters that affect the specification of the produced layer. The obtained results showed surface development and different sized pores in the modified layers, as well as an increase in corrosion resistance in the Ringer's solution.
Molecular details of BSA adsorption on a silica surface are revealed by fully atomistic molecular dynamics (MD) simulations (with a 0.5 μs trajectory), supported by dynamic light scattering (DLS), ...zeta potential, multiparametric surface plasmon resonance (MP-SPR), and contact angle experiments. The experimental and theoretical methods complement one another and lead to a wider understanding of the mechanism of BSA adsorption across a range of pH 3–9. The MD results show how the negatively charged BSA at pH7 adsorbs to the negatively charged silica surface, and reveal a unique orientation with preserved secondary and tertiary structure. The experiments then show that the protein forms complete monolayers at ∼ pH6, just above the protein’s isoelectric point (pH5.1). The surface contact angle is maximum when it is completely coated with protein, and the hydrophobicity of the surface is understood in terms of the simulated protein conformation. The adsorption behavior at higher pH > 6 is also consistently interpreted using the MD picture; both the contact angle and the adsorbed protein mass density decrease with increasing pH, in line with the increasing magnitude of negative charge on both the protein and the surface. At lower pH < 5 the protein starts to unfold, and the adsorbed mass dramatically decreases. The comprehensive picture that emerges for the formation of oriented protein films with preserved native conformation will help guide efforts to create functional films for new technologies.
Fluorescent gold nanoclusters encapsulated by proteins have attracted considerable attention in recent years for their unique properties as new fluorescence probes for biological sensing and imaging. ...However, fundamental questions, such as the nucleation sites of gold nanoclusters within proteins and the fluorescence mechanism remain unsolved. Here we present a study of the location of gold nanoclusters within bovine serum albumin (BSA) combining both fully atomistic molecular dynamic (MD) simulations and fluorescence spectroscopic studies. The MD simulations show gold clusters growing close to a number of cysteine sites across all three domains of BSA, although just two major sites in domains IIB and IA were found to accommodate large clusters comprising more than 12 atoms. The dependence of the fluorescence on pH is found to be compatible with possible nucleation sites in domains IIB and IA. Furthermore, the energy transfer between tryptophan and gold nanoclusters reveals a separation of 29.7 Å, further indicating that gold nanoclusters were most likely located in the major nucleation site in domain IIB. The disclosure of the precise location of the gold nanoclusters and their surrounding amino acid residues should help better understanding of their fluorescence mechanism and aid their optimization as fluorescent nanoprobes.
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