38 research outputs found

    The influence of different prefermentative maceration processes and tartaric stabilization treatments on the color, cation content and other physico-chemical parameters of 'Băbească neagră' rosé wines

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    This study enhances knowledge in the physicochemical and color parameters of rosé wines produced by the prefermentative maceration of native Romanian 'Băbească neagră' (Vitis vinifera L.) grape varieties, both before and after tartaric stabilization treatments by the contact procedure in an MK70 ultra-refrigerator. One variety was prepared without maceration as a control sample and the other was subjected to the maceration process for one of the following seven periods of time: 3.5 hours, 7 hours, 10.5 hours, 14 hours, 17.5 hours, 21 hours and 24.5 hours. The prefermentative maceration process exerts a significant influence on the amount of volatile acids, on the pH, conductivity and the K+ cation. The phenolic compound content, the chromatic parameters and the cation content of wines are significantly influenced by both prefermentative maceration and tartaric stabilization. The multifactor ANOVA tests prove that there is an interaction for all parameters except for total acidity.

    FORMATION OF THE PEDIATRIC ELECTRORETINOGRAM DATABASE PARAMETERS FOR THE DEVELOPMENT OF DOCTOR’S DECISION-MAKING ALGORITHM

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    Electroretinography is a non-invasive electrophysiological method standardized by the International Society for Clinical Electrophysiology of Vision (ISCEV). Electroretinography has been used for the clinical application and standardization of electrophysiological protocols for diagnosing the retina since 1989. Electroretinography becomefundamentalophthalmologicalresearchmethodthatmayassessesthestate oftheretina. Totransferclinicalpracticeto patientstheestablishmentofstandardized protocols is an important step. It is important for monitoring successful molecular therapy in retinaldegeneration. Retinitis pigmentosa or achromatopsia and, consequently, affected cones or rods photoreceptors is corresponded to complete absent ofelectricalresponse. Thus, detection ofeven modestimprovements after therapeutic treatment is required. Standardized protocols allow the implementation of electroretinography under conditions of optimization of sensitivity and specificity during clinical trials. It should be noted that the literature on retinal diseases demonstrates clinical cases in which patients may have several retinal diseases at the same time. In such cases, it is necessary to detect a group of characteristics of electrophysiological signals withhigh accuracy to improve the application ofvarious diagnostic solutions. The classification of electroretinogram signals depends on the quality of labeled biomedical information or databases, in addition to this, the accuracy of the classification results obtained depends not only on computer technology, but also on the quality of the input data. To date, the analysis of electroretinogram signals is realized manually and largely depends on the experience of clinicians. The development of automated algorithms for analyzing electroretinogram signals may simplify routine processes and improve the quality of diagnosing eye diseases. This article describes the formation ofthe parameters of pediatric electroretinogram database parameters for the development of doctor’s decision-making algorithm. The signal parameters were obtainedby extracting the parameters from the wavelet scalogram of the electroretinogram signal using digital image processing and machine learning methods. © 2022 Scientific Research Institute — Ochapovsky Clinical Regional Hospital no. 1. All Rights Reserved

    Does Death Anxiety Inhibit Product Innovation? An Exploratory Study in Small Manufacturing Companies

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    The study analyzed the entrepreneurs’ choice for explorative and exploitative innovation and their effects on product innovation. Death anxiety, a psychological factor, is analyzed as it is assumed to be important in mediating the relationship between explorative or exploitative innovation and product innovation. A sample of 60 entrepreneurs from small manufacturing companies was analyzed in three waves over three consecutive years, while the data was analyzed using PLS-SEM. Empirical evidence supports the assumption that entrepreneurs’ fear of death partially mediates explorative and exploitative innovation influence on product innovation. The findings show that death anxiety is negatively affecting explorative innovation, with negative effects for radical innovation, and positively influencing exploitative innovation, supporting incremental innovation. The effects may be far reaching, only if considering the current SARS-COV-2 epidemics, which may radically change not only the social landscape, but also the way the entrepreneurs are substantiating their decisions

    Protein Nanopore-Based Discrimination between Selected Neutral Amino Acids from Polypeptides

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    Nanopore probing of biological polymers has the potential to achieve single-molecule sequencing at low cost, high throughput, portability, and minimal sample preparation and apparatus. In this article, we explore the possibility of discrimination between neutral amino acid residues from the primary structure of 30 amino acids long, engineered peptides, through the analysis of single-molecule ionic current fluctuations accompanying their slowed-down translocation across the wild type α-hemolysin (α-HL) nanopore, and molecular dynamics simulations. We found that the transient presence inside the α-HL of alanine or tryptophan residues from the primary sequence of engineered peptides results in distinct features of the ionic current fluctuation pattern associated with the peptide reversibly blocking the nanopore. We propose that α-HL sensitivity to the molecular exclusion at the most constricted region mediates ionic current blockade events correlated with the volumes that are occluded by at least three alanine or tryptophan residues, and provides the specificity needed to discriminate between groups of neutral amino acids. Further, we find that the pattern of current fluctuations depends on the orientation of the threaded amino acid residues, suggestive of a conformational anisotropy of the ensemble of conformations of the peptide on the restricted nanopore region, related to its relative axial orientation inside the nanopore

    The Role of Lys147 in the Interaction between MPSA-Gold Nanoparticles and the α‑Hemolysin Nanopore

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    Single channel recordings were used to determine the effect of direct electrostatic interactions between sulfonate-coated gold nanoparticles and the constriction of the Staphylococcus aureus α-hemolysin protein channel on the ionic current amplitude. We provide evidence that Lys147 of α-hemolysin can interact with the sulfonate groups at the nanoparticle surface, and these interactions can reversibly block 100% of the residual ionic current. Lys147 is normally involved in a salt bridge with Glu111. The capture of a nanoparticle leads to a partial current block at neutral pH values, but protonation of Glu111 at pH 2.8 results in a full current block when the nanoparticle is captured. At pH 2.8, we suggest that Lys147 is free to engage in electrostatic interactions with sulfonates at the nanoparticle surface. To verify our results, we engineered a mutation in the α-hemolysin protein, where Glu111 is substituted by Ala (E111A), thus removing Glu111–Lys147 interactions and facilitating Lys147–sulfonate electrostatic interactions. This mutation leads to a 100% current block at pH 2.8 and a 92% block at pH 8.0, showing that electrostatic interactions are formed between the nanopore and the nanoparticle surface. Besides demonstrating the effect of electrostatic interactions on cross channel ionic current, this work offers a novel approach to controlling open and closed states of the α-hemolysin nanopore as a function of external gears
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