Namen raziskave je bil ugotoviti vpliv različnih tehnoloških postopkov predelave grozdja in pridelave vina na fizikalne in kemijske parametre vina ter njegovo senzorično kakovost. Za izvedbo poskusa ...smo izbrali vina sorte malvazija (letnik 2007), pridelana na območju Slovenske in Hrvaške Istre. Vina so pridelana po treh tehnoloških postopkih: klasičnem postopku, z maceracijo drozge in z zorenjem vina na drožeh. Pri nekaterih vzorcih je bila uporabljena kombinacija več postopkov (hladna maceracija in zorenje vina na drožeh). Pri vinih smo določili pH, vsebnost titrabilnih kislin, vsebnost hlapnih kislin, pufrno kapaciteto, sladkorja prostega ekstrakta, vsebnost alkohola, relativno gostoto, vsebnost reducirajočih sladkorjev, vsebnost prostega in skupnega SO2, vsebnost fenolov, taninskih fenolov, intenziteto barve ter vsebnost nekaterih hlapnih aromatičnih snovi. Poleg tega smo vina tudi senzorično ocenili in rezultate statistično izvrednotili. Ugotovili smo, da uporaba različnih tehnoloških postopkov predelave grozdja in pridelave vina značilno vpliva na vse fizikalne in kemijske parametre vina. Analiza korelacijskih koeficientov je pokazala številne pozitivne in negativne korelacije med izmerjenimi parametri. Analiza glavnih komponent je pokazala, da je večina variabilnosti med vzorci posledica različne intenzitete barve ter različnih koncentracij fenolov metanola, etil acetata in izoamil acetata. Pri senzorični analizi so najboljše ocenjena vina, pridelana po tehnologiji zorenja vina na drožeh.
Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of ...contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)
-Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)
-Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This promising concept of an electrochemical IoT sensor that is easy to operate, rapid, and affordable (it is considerably cheaper than any lab-grade potentiostat) could lead to the straightforward detection of HCHO in tap water.
In this work, we have applied the concept of α-hydrazino acid insertion in a peptide sequence as a means of structurally organizing a potential protein–protein interactions (PPI) inhibitor. Hydrazino ...peptides characterized by the incorporation of an α-hydrazino acid at specific positions introduce an additional nitrogen atom into their backbone. This modification leads to a change in the electrostatic properties of the peptide and induces the restructuring of its hydrogen bonding network, resulting in conformational changes toward more stable structural motifs. Despite the successful use of synthetic hydrazino oligomers in binding to nucleic acids, the structural changes due to the incorporation of α-hydrazino acid into short natural peptides in solution are still poorly understood. Based on NMR data, we report structural models of p53-derived hydrazino peptides with elements of localized peptide structuring in the form of an α-, β-, or γ-turn as a result of hydrazino modification in the peptide backbone. The modifications could potentially lead to the preorganization of a helical secondary peptide structure in a solution that is favorable for binding to a biological receptor. Spectroscopically, we observed that the ensemble averaged rapidly interconverting conformations, including isomerization of the E–Z hydrazide bond. This further increases the adaptability by expanding the conformational space of hydrazine peptides as potential protein–protein interaction antagonists.
Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of ...contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)sub.2-Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)sub.2-Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This promising concept of an electrochemical IoT sensor that is easy to operate, rapid, and affordable (it is considerably cheaper than any lab-grade potentiostat) could lead to the straightforward detection of HCHO in tap water.
Application of laboratory-based X-ray analytical techniques that are capable of a reliable characterization of the chemical state of sulfur within bulk battery cathode in parallel with ...electrochemical characterization is essential for further development of lithium–sulfur batteries. In this work, MeV proton-induced X-ray emission (XES) sulfur measurements were performed in ex situ mode on laboratory-synthesized sulfur standards and precycled battery cathodes. The average sulfur charge was determined from the energy shift of the Kα emission line and from the spectral shape of the Kβ emission spectrum. Finally, operando Kα XES measurements were performed to monitor reduction of sulfur within battery cathode during discharge. The experimental approach presented here provides an important step toward more routine laboratory analysis of sulfur-based battery systems and also other sulfur-neighboring low-Z bulk materials with emission energies in the tender X-ray range.
The use of screen-printed electrodes in different monitoring applications, e.g., polluted water, biotechnology, agriculture, industrial process control, and other applications, are continuously being ...developed. New cheap and open-source potentiostats have been recently emerging, in addition to the commercial and proprietary solutions on the market. In this study, paper-based, screen-printed electrodes were utilised as an alternative solution for ceramic-based electrodes and were tested with two potentiostats (proprietary and low-cost open-source running on wireless 64 bit Linux system installed on Raspberry Pi 3+). Unique paper substrates made from invasive plant papers and one commercial product were used for screen electrode printing. Ink layer thicknesses variations and mechanical grinding were applied, and cyclic voltammetry measurements were conducted. The variation in cyclic voltammetry measurements could be attributed to two sources: the potentiostats showed differences in their sensibility and signal values, and paper surface and structure also contributed to differences. Simultaneously, the additional processing steps, e.g., mechanical grinding, introduced additional measurement variations and differences in the measurement process.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Potato virus Y (PVY) is among the most economically important plant pathogens. Using cryoelectron microscopy, we determined the near-atomic structure of PVY's flexuous virions, revealing a previously ...unknown lumenal interplay between extended carboxyl-terminal regions of the coat protein units and viral RNA. RNA-coat protein interactions are crucial for the helical configuration and stability of the virion, as revealed by the unique near-atomic structure of RNA-free virus-like particles. The structures offer the first evidence for plasticity of the coat protein's amino- and carboxyl-terminal regions. Together with mutational analysis and in planta experiments, we show their crucial role in PVY infectivity and explain the ability of the coat protein to perform multiple biological tasks. Moreover, the high modularity of PVY virus-like particles suggests their potential as a new molecular scaffold for nanobiotechnological applications.
Potato virus Y (PVY), the type member of the genus
(family
), is the most widespread virus affecting potato and is included in the top five most economically detrimental plant viruses. Recently, the ...structure of the PVY virion has been determined by cryo-electron microscopy, which has opened the doors to functional studies that explore the involvement of selected amino acids in different stages of the viral cycle. The only way to functionally challenge
the role of particular amino acids in the coat protein of PVY, or in other viral proteins, is by using cDNA clones. The use and manipulation of PVY cDNA clones, unlike those of other potyviruses, has been traditionally impaired by the toxicity that certain sequences within the PVY genome pose to
. Here, we describe the use of a published PVY cDNA clone, which harbours introns that overcome the aforementioned toxicity, to explore the effects of different coat protein modifications on viral infection. The protocol includes manipulation of the cDNA clone in
, biolistic inoculation of plants with the constructed clones, observation of the biological effects on plants, quantification of cDNA clones by reverse transcription quantitative PCR, and confirmation of virion formation by transmission electron microscopy. Future possibilities involve the use of PVY cDNA clones tagged with fluorescent protein reporters to allow further insights into the effects of coat protein mutations on the cell-to-cell movement of PVY virions.
To examine the effect of acute sleep deprivation under light conditions on the expression of two key clock genes, hPer2 and hBmal1, in peripheral blood mononuclear cells (PBMC) and on plasma ...melatonin and cortisol levels.
Blood samples were drawn from 6 healthy individuals at 4-hour intervals for three consecutive nights, including a night of total sleep deprivation (second night). The study was conducted in April-June 2006 at the University Medical Centre Ljubljana.
We found a significant diurnal variation in hPer2 and hBmal1 expression levels under baseline (P<0.001, F=19.7, df=30 for hPer2 and P<0.001, F=17.6, df=30 for hBmal1) and sleep-deprived conditions (P<0.001, F=9.2, df=30 for hPer2 and P<0.001, F=13.2, df=30 for hBmal1). Statistical analysis with the single cosinor method revealed circadian variation of hPer2 under baseline and of hBmal1 under baseline and sleep-deprived conditions. The peak expression of hPer2 was at 13:55 ± 1:15 hours under baseline conditions and of hBmal1 at 16:08 ± 1:18 hours under baseline and at 17:13 ± 1:35 hours under sleep-deprived conditions. Individual cosinor analysis of hPer2 revealed a loss of circadian rhythm in 3 participants and a phase shift in 2 participants under sleep-deprived conditions. The plasma melatonin and cortisol rhythms confirmed a conventional alignment of the central circadian pacemaker to the habitual sleep/wake schedule.
Our results suggest that 40-hour acute sleep deprivation under light conditions may affect the expression of hPer2 in PBMCs..
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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