| | SLO | ENG | Piškotki in zasebnost

Večja pisava | Manjša pisava

Iskanje po katalogu digitalne knjižnice Pomoč

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


1 - 10 / 40
Na začetekNa prejšnjo stran1234Na naslednjo stranNa konec
1.
Microbiota in vitro modulated with polyphenols shows decreased colonization resistance against Clostridioides difficile but can neutralize cytotoxicity
Aleksander Mahnič, Jennifer Auchtung, Nataša Poklar Ulrih, Robert A. Britton, Maja Rupnik, 2020, izvirni znanstveni članek

Opis: While the knowledge on gut microbiota - C. difficile interactions has improved over the years, the understanding of the underlying mechanisms providing colonization resistance as well as preventative measures against the infection remain incomplete. In this study the antibiotic clindamycin and polyphenol extracts from pomegranate and blueberries were used individually and in combination to modulate fecal microbial communities in minibioreactor arrays (MBRA). Modulated communities were inoculated with C. difficile (ribotype 027). Subsequent 7-day periodical monitoring included evaluation of C. difficile growth and activity of toxins TcdA and TcdB as well as analysis of MBRA bacterial community structure (V3V4 16%S metagenomics). Polyphenols affected multiple commensal bacterial groups and showed different synergistic and antagonistic effects in combination with clindamycin. Exposure to either clindamycin or polyphenols led to the loss of colonization resistance against C. difficile. The successful growth of C. difficile was most significantly correlated with the decrease in Collinsella and Lachnospiraceae. Additionally, we demonstrated that Clostridium sporogenes decreased the activity of both C. difficile toxins TcdA and TcdB. The feature was shown to be common among distinct C. sporogenes strains and could potentially be applicable as a non-antibiotic agent for the alleviation of C. difficile infection.
Ključne besede: microbiota in vitro, Clostridioides difficile, resistance, cytotoxicity
Objavljeno v DKUM: 29.01.2025; Ogledov: 0; Prenosov: 2
.pdf Celotno besedilo (1,67 MB)
Gradivo ima več datotek! Več...

2.
The relation between project team conflict and user resistance in software projects
Simon Vrhovec, Blaž Markelj, 2021, izvirni znanstveni članek

Opis: This study aims to explore the relation between conflict in the project team and user resistance to change in software projects. Following a cross-sectional research design, a survey was conducted among 1,000 largest companies in Slovenia (N = 114). The results of PLSSEM analysis indicate that task and process conflicts in the project team are associated with user resistance. This study is among the first to associate conflict within the project team and user resistance in the implementing organization. It is also one of the first studies to investigate the relations between different types of conflict and user resistance. Project managers may invest resources into adequately managing conflicts within the project team related to tasks in which the project team interacts with users of developed software to lower user resistance. Project with poorly defined roles (e.g., agile and information security projects) may be more prone to user resistance than projects with clearly defined roles.
Ključne besede: project management, software project, relationship conflict, task conflict, process conflict, resistance to change
Objavljeno v DKUM: 11.12.2024; Ogledov: 0; Prenosov: 2
.pdf Celotno besedilo (589,11 KB)
Gradivo ima več datotek! Več...

3.
Reduced susceptibility and increased resistance of bacteria against disinfectants : a systematic review
Urška Rozman, Marko Pušnik, Sergej Kmetec, Darja Duh, Sonja Šostar-Turk, 2021, pregledni znanstveni članek

Opis: Disinfectants are used to reduce the concentration of pathogenic microorganisms to a safe level and help to prevent the transmission of infectious diseases. However, bacteria have a tremendous ability to respond to chemical stress caused by biocides, where overuse and improper use of disinfectants can be reflected in a reduced susceptibility of microorganisms. This review aims to describe whether mutations and thus decreased susceptibility to disinfectants occur in bacteria during disinfectant exposure. A systematic literature review following PRISMA guidelines was conducted with the databases PubMed, Science Direct and Web of Science. For the final analysis, 28 sources that remained of interest were included. Articles describing reduced susceptibility or the resistance of bacteria against seven different disinfectants were identified. The important deviation of the minimum inhibitory concentration was observed in multiple studies for disinfectants based on triclosan and chlorhexidine. A reduced susceptibility to disinfectants and potentially related problems with antibiotic resistance in clinically important bacterial strains are increasing. Since the use of disinfectants in the community is rising, it is clear that reasonable use of available and effective disinfectants is needed. It is necessary to develop and adopt strategies to control disinfectant resistance.
Ključne besede: antimicrobial resistance, susceptibility, disinfectants, bacteria
Objavljeno v DKUM: 09.12.2024; Ogledov: 0; Prenosov: 2
.pdf Celotno besedilo (585,04 KB)
Gradivo ima več datotek! Več...

4.
Experimental characterization and phase-field damage modeling of ductile fracture in AISI 316l
Vladimir Dunić, Nenad Gubeljak, Miroslav Živković, Vladimir Milovanović, Darko Jagarinec, Nenad Djordjevic, 2024, izvirni znanstveni članek

Opis: ) Modeling and characterization of ductile fracture in metals is still a challenging task in the field of computational mechanics. Experimental testing offers specific responses in the form of crack-mouth (CMOD) and crack-tip (CTOD) opening displacement related to applied force or crack growth. The main aim of this paper is to develop a phase-field-based Finite Element Method (FEM) implementation for modeling of ductile fracture in stainless steel. (2) A Phase-Field Damage Model (PFDM) was coupled with von Mises plasticity and a work-densities-based criterion was employed, with a threshold to propose a new relationship between critical fracture energy and critical total strain value. In addition, the threshold value of potential internal energy—which controls damage evolution—is defined from the critical fracture energy. (3) The material properties of AISI 316L steel are determined by a uniaxial tensile test and the Compact Tension (CT) specimen crack growth test. The PFDM model is validated against the experimental results obtained in the fracture toughness characterization test, with the simulation results being within 8% of the experimental measurements.
Ključne besede: phase-field damage modeling, ductile fracture, crack-tip opening displacement, crack growth, resistance curve, finite element method, simulations
Objavljeno v DKUM: 19.09.2024; Ogledov: 0; Prenosov: 8
.pdf Celotno besedilo (3,84 MB)
Gradivo ima več datotek! Več...

5.
Hemodynamic response to high- and low-load resistance exercise in patients with coronary artery disease : a randomized, crossover clinical trial
Tim Kambič, Vedran Hadžić, Mitja Lainščak, 2021, izvirni znanstveni članek

Opis: Low-load resistance exercise (LL-RE) is recommended as an adjunct therapy to aerobic exercise during cardiac rehabilitation in patients with coronary artery disease. The safety and hemodynamic response to high-load (HL) RE remain unknown. The aim of this study was to evaluate the hemodynamic response during both HL-RE and LL-RE prior to cardiac rehabilitation. Forty-three patients with coronary artery disease and/or percutaneous coronary intervention performed three sets of leg-press exercise using HL-RE (eight repetitions at the intensity of 80% of one repetition maximum (1-RM)) and LL-RE (16 repetitions at the intensity of 40% 1-RM) in a randomized crossover sequence. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and rating of perceived exertion were measured at baseline, after each set of RE and post-exercise. No clinically relevant changes in HR and BP or in patient-reported symptoms were recorded during HL-RE or LL-RE. Compared with baseline, HR and SBP increased during LL-RE (from 66 bpm to 86 bpm, time effect: p < 0.001; from 129 mmHg to 146 mmHg, time effect: p < 0.001) and HL-RE (from 68 bpm to 86 bpm, time effect: p < 0.001; from 130 mmHg to 146 mmHg, time effect: p < 0.001). Compared with HL-RE, the increase in HR was greater after the final set of LL-RE (32% vs. 28%, p = 0.015), without significant differences in SBP and DBP between LL-RE and HL-RE. Rating of perceived exertion was higher after the 1st set of HL-RE compared with LL-RE (median (interquartile range): 6 (5–7) vs. 6 (5–6), p = 0.010). In patients with coronary artery disease, both HL-RE and LL-RE were safe and well-tolerated. Hemodynamic changes were similar and within the physiological response to RE.
Ključne besede: sport, cardiac rehabilitation, resistance training, blood pressure, heart rate
Objavljeno v DKUM: 20.08.2024; Ogledov: 85; Prenosov: 10
.pdf Celotno besedilo (726,02 KB)
Gradivo ima več datotek! Več...

6.
Derivation of analytical expressions for fast calculation of resistance spot welding system currents
Robert Brezovnik, Jožef Ritonja, 2024, izvirni znanstveni članek

Opis: The paper deals with the dynamics of a resistance spot welding system. At the core of this system is a transformer, which is powered on the primary side by a pulse-width modulated inverter and has a full-wave output rectifier on the secondary side that provides a direct welding current. The entire system is nonlinear, due to magnetic hysteresis and electronics. The electronics prevent the current from flowing in all parts of the welding transformer at separate time intervals during the voltage supply period; therefore, not all the parameters affect the dynamic of currents and voltages all the time so the system is also time-variant. To design a high-performance welding system and to predict the maximum possible welding current at a specific load, it is necessary to know the welding and primary currents. The leakage inductances of the system can reduce the maximum welding current significantly at higher frequencies and the same load. There are several methods to determine these currents, each with its drawbacks. Measurements are time-consuming, using professional software is expensive and requires time to learn and free open-source software has many limitations and does not guarantee the correctness of the results. The article presents a new, fourth option—a theoretical derivation of analytical expressions that facilitate straightforward and rapid calculation of the welding and primary currents of the resistance spot welding system with symmetrical secondary branches. The derivation of the mathematical expressions is based on the equivalent circuits that describe the system in different operating states. The results of the numerical simulations confirmed the derived expressions completely.
Ključne besede: DC–DC converters, pulse width modulation (PWM), welding transformers, center-tapped transformers, full-wave rectifier, resistance spot welding (RSW), leakage inductance, analytical modeling, time-variant system, equivalent circuit
Objavljeno v DKUM: 08.08.2024; Ogledov: 77; Prenosov: 28
.pdf Celotno besedilo (6,72 MB)

7.
ǂThe ǂcorrosion resistance of dental Ti6Al4V with differing microstructures in oral environments
Mirjam Bajt Leban, Tadeja Kosec, Matjaž Finšgar, 2023, izvirni znanstveni članek

Opis: The impact of the microstructural properties of a Ti6Al4V alloy on its electrochemical properties, as well as the effect of the α- and β-phases present within it, is still unclear. With the introduction of new, emerging technologies, such as selective laser melting and post heat treatments, the effect of the microstructure on an alloy's corrosion properties has become increasingly interesting from a scientific perspective. When these alloys are produced through different methods, despite an identical chemical composition they have diverse microstructures, and consequently display varying resistance to corrosion. In the present research study, Ti–6Al–4V alloy specimens produced by three different processes, leading to the formation of three different microstructures were investigated: heat treated specimen fabricated by selective laser melting, wrought and cast specimens. The impact of the microstructure of these alloys when immersed in artificial saliva was studied through the use of various electrochemical techniques, by microscopical examinations, and time-of-flight secondary ion mass spectrometry. Corrosion properties were investigated by the measurement of open circuit potential, linear polarization, and potentiodynamic curve measurements followed by microscopical examinations, and time-of-flight secondary ion mass spectrometry examination was conducted to reveal spatial distribution of alloying species on oxide film. It was found that the difference between specimens containing an α+β microstructure was small and not dependent on the aspect ratio of the β-phase, alloy grain size, and vanadium partitioning coefficient, but rather on the size, shape, and content of this phase.
Ključne besede: Ti6Al4V, dental alloy, microstructure, corrosion resistance, heat treatment, ToF-SIMS
Objavljeno v DKUM: 07.05.2024; Ogledov: 198; Prenosov: 13
.pdf Celotno besedilo (8,12 MB)
Gradivo ima več datotek! Več...

8.
Human beta cell functional adaptation and dysfunction in insulin resistance and its reversibility
Maša Skelin, Jan Kopecky, Jurij Dolenšek, Andraž Stožer, 2023, drugi znanstveni članki

Opis: Background: Beta cells play a key role in the pathophysiology of diabetes since their functional adaptation is able to maintain euglycemia in the face of insulin resistance, and beta cell decompensation or dysfunction is a necessary condition for full-blown type 2 diabetes (T2D). The mechanisms behind compensation and decompensation are incompletely understood, especially for human beta cells, and even less is known about influences of chronic kidney disease (CKD) or immunosupressive therapy after transplantation on these processes and the development of posttransplant diabetes. Summary: During compensation, beta cell sensitivity to glucose becomes left-shifted, i.e., their sensitivity to stimulation increases, and this is accompanied by enhanced signals along the stimulus-secretion coupling cascade from membrane depolarization to intracellular calcium and the most distal insulin secretion dynamics. There is currently no clear evidence regarding changes in intercellular coupling during this stage of disease progression. During decompensation, intracellular stimulus-secretion coupling remains enhanced to some extent at low or basal glucose concentrations but seems to become unable to generate effective signals to stimulate insulin secretion at high or otherwise stimulatory glucose concentrations. Additionally, intercellular coupling becomes disrupted, lowering the number of cells that contribute to secretion. During progression of CKD, beta cells also seem to drift from a compensatory left-shift to failure, and immunosupressants can further impair beta cell function following kidney transplantation. Key Messages: Beta cell stimulus-secretion coupling is enhanced in compensated insulin resistance. With worsening insulin resistance, both intra- and intercellular coupling become disrupted. CKD can progressively disrupt beta cell function, but further studies are needed, especially regarding changes in intercellular coupling.
Ključne besede: human beta cell, functional adaptation, dysfunction, insulin resistance
Objavljeno v DKUM: 15.04.2024; Ogledov: 201; Prenosov: 28
.pdf Celotno besedilo (387,53 KB)
Gradivo ima več datotek! Več...

9.
10.
Numerical analysis of the racking behaviour of multi-storey timber-framed buildings considering load-bearing function of double-skin façade elements
Miroslav Premrov, Erika Kozem Šilih, 2023, izvirni znanstveni članek

Opis: The paper presents an innovative approach in the modelling of multi-storey timber-framed buildings, where double-skin façade elements (DSF) are additionally considered as load-bearing wall elements against a horizontal load impact. The mathematical model with a fictive diagonal element developed for timber-framed wall elements with classical oriented strand boards (OSB) or fibre–plaster sheathing boards (FPB) is upgraded for DSF elements. The diameter of the fictive diagonal is determined with either experimental results or numerically obtained results using the time-consuming FEM model with elastic spring elements, which simulates the bonding line between the timber frame and both glazing panes. In the second part of the study, the numerical analysis of a specially selected three-storey timber-framed building was performed using the developed mathematical model with fictive diagonal elements. Two alternative calculations were performed with the DSF elements as non-resisting and racking-resisting wall elements. It was demonstrated on the selected case that the racking resistance (R) of a building can essentially increase up to 35% if DSF elements are considered as resisting wall elements. As a secondary goal of the study, it is also important to point out that by using DSF elements as racking-resisting elements, the distortion in the first floor essentially decreased. It is demonstrated on the selected numerical example that this torsional influence decreased notably (by almost 18%) when the load-bearing DSF elements were used for seismic excitation in the X direction. Therefore, such an approach can open new perspectives in designing multi-storey timber-framed buildings with a more attractive and dynamic floor plan and structure.
Ključne besede: sustainability, timber, structures, multi-storey, numerical analysis, DSF, racking resistance
Objavljeno v DKUM: 19.03.2024; Ogledov: 225; Prenosov: 34
.pdf Celotno besedilo (4,93 MB)
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.26 sek.
Na vrh
Logotipi partnerjev Univerza v Mariboru Univerza v Ljubljani Univerza na Primorskem Univerza v Novi Gorici