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  • 1
    Online Resource
    Online Resource
    In Situ Measurements of the Chemical Stability of a Cast Aluminum Alloy Embedded in a Cement Paste with a High Amount of Supplementary Cementitious Material
    MDPI AG ; 2021
    In:  Metals Vol. 11, No. 9 ( 2021-09-11), p. 1441-
    Details
    In: Metals, MDPI AG, Vol. 11, No. 9 ( 2021-09-11), p. 1441-
    Abstract: In traditional reinforced concrete, the alkaline pore solution which passivates the steel rebars will get neutralized with time in an exposed environment. Therefore, to prevent corrosion initiation, the permeability of the concrete is reduced and extra-thick concrete covers the steel rebars. Aluminum is passive in the neutralized environment, but the calcium hydroxide formed during the cement hydration will dissolve the aluminum. By substituting 55% of the cement in traditional cement paste with fast reactive supplementary cementitious material (SCM), aluminum will be compatible over time. In the initial state however, before the SCM consumes the hydroxide formed during the rapid cement hydration by the pozzolanic reaction, aluminum may corrode. Hydrogen gas then develops, resulting in a porous cement region enclosing the rebars with potentially reduced bond strength. In the present work, the chemical stability of a sand-cast aluminum lattice embedded in a paste where cement is replaced by 55% calcined kaolinitic clay is investigated by gas chromatography and open-circuit potential during the cement hydration. The hydrogen gas development stagnated for all measurements, indicating that aluminum is compatible with the novel cement paste. Two stable potentials were observed for the non-heat-treated samples, indicating the formation of a metastable complex. Being able to use aluminum-reinforced concrete constructions would result in an extraordinary long service life with low cement consumption, which will potentially result in a substantial reduction in the third-largest CO2 emitting industry.
    Type of Medium: Online Resource
    ISSN: 2075-4701
    URL: Article
    DOI: 10.3390/met11091441
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662252-X
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  • 2
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    Online Resource
    Influence of Silica Specific Surface Area on the Viscoelastic and Fatigue Behaviors of Silica-Filled SBR Composites
    MDPI AG ; 2021
    In:  Polymers Vol. 13, No. 18 ( 2021-09-14), p. 3094-
    Details
    In: Polymers, MDPI AG, Vol. 13, No. 18 ( 2021-09-14), p. 3094-
    Abstract: This work aimed at studying the effect of a silica specific surface area (SSA), as determined by the nitrogen adsorption method, on the viscoelastic and fatigue behaviors of silica-filled styrene–butadiene rubber (SBR) composites. In particular, silica fillers with an SSA of 125 m2/g, 165 m2/g, and 200 m2/g were selected. Micro-computed X-ray tomography (µCT) was utilized to analyze the 3D morphology of the fillers within an SBR matrix prior to mechanical testing. It was found with this technique that the volume density of the agglomerates drastically decreased with decreasing silica SSA, indicating an increase in the silica dispersion state. The viscoelastic behavior was evaluated by dynamic mechanical analysis (DMA) and hysteresis loss experiments. The fatigue behavior was studied by cyclic tensile loading until rupture enabled the generation of Wöhler curves. Digital image correlation (DIC) was used to evaluate the volume strain upon deformation, whereas µCT was used to evaluate the volume fraction of the fatigue-induced cracks. Last, scanning electron microscopy (SEM) was used to characterize, in detail, crack mechanisms. The main results indicate that fatigue life increased with decreasing silica SSA, which was also accompanied by a decrease in hysteresis loss and storage modulus. SEM investigations showed that filler–matrix debonding and filler fracture were the mechanisms at the origin of crack initiation. Both the volume fraction of the cracks obtained by µCT and the volume strain acquired from the DIC increased with increasing SSA of silica. The results are discussed based on the prominent role of the filler network on the viscoelastic and fatigue damage behaviors of SBR composites.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    URL: Article
    DOI: 10.3390/polym13183094
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527146-5
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  • 3
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    Online Resource
    Amidochelocardin Overcomes Resistance Mechanisms Exerted on Tetracyclines and Natural Chelocardin
    MDPI AG ; 2020
    In:  Antibiotics Vol. 9, No. 9 ( 2020-09-18), p. 619-
    Details
    In: Antibiotics, MDPI AG, Vol. 9, No. 9 ( 2020-09-18), p. 619-
    Abstract: The reassessment of known but neglected natural compounds is a vital strategy for providing novel lead structures urgently needed to overcome antimicrobial resistance. Scaffolds with resistance-breaking properties represent the most promising candidates for a successful translation into future therapeutics. Our study focuses on chelocardin, a member of the atypical tetracyclines, and its bioengineered derivative amidochelocardin, both showing broad-spectrum antibacterial activity within the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) panel. Further lead development of chelocardins requires extensive biological and chemical profiling to achieve favorable pharmaceutical properties and efficacy. This study shows that both molecules possess resistance-breaking properties enabling the escape from most common tetracycline resistance mechanisms. Further, we show that these compounds are potent candidates for treatment of urinary tract infections due to their in vitro activity against a large panel of multidrug-resistant uropathogenic clinical isolates. In addition, the mechanism of resistance to natural chelocardin was identified as relying on efflux processes, both in the chelocardin producer Amycolatopsis sulphurea and in the pathogen Klebsiella pneumoniae. Resistance development in Klebsiella led primarily to mutations in ramR, causing increased expression of the acrAB-tolC efflux pump. Most importantly, amidochelocardin overcomes this resistance mechanism, revealing not only the improved activity profile but also superior resistance-breaking properties of this novel antibacterial compound.
    Type of Medium: Online Resource
    ISSN: 2079-6382
    URL: Article
    DOI: 10.3390/antibiotics9090619
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2681345-2
    SSG: 15,3
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  • 4
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    Online Resource
    Prognostic Value of Different Levels of Uric Acid in Patients with Coronary Chronic Total Occlusion Undergoing Percutaneous Coronary Intervention
    MDPI AG ; 2023
    In:  Journal of Clinical Medicine Vol. 12, No. 11 ( 2023-05-31), p. 3794-
    Details
    In: Journal of Clinical Medicine, MDPI AG, Vol. 12, No. 11 ( 2023-05-31), p. 3794-
    Abstract: Recent data suggest that uric acid (UA) might be an independent predictor of clinical outcomes following percutaneous coronary intervention (PCI). The predictive value of uric acid in patients undergoing PCI for chronic total occlusions (CTO) is unknown. We included patients with CTO who underwent PCI at our center in 2005 and 2012, with available uric acid levels before angiography. Subjects were divided into groups according to uric acid tertiles ( 〈 5.5 mg/dL, 5.6–6.9 mg/dL, and 〉 7.0 mg/dL), and outcomes were compared among the groups. Out of the 1963 patients (mean age 65.2 ± 11 years), 34.7% (n = 682) had uric acid concentrations in the first tertile, 34.3% (n = 673) in the second tertile, and 31% (n = 608) in the third tertile. Median follow-up was 3.0 years. Uric acid levels in the first tertile were associated with significantly lower all-cause mortality, as compared to the third tertile, with an adjusted hazard ratio (HR) of 0.67 (95% confidence interval (CI): 0.49 to 0.92; p = 0.012). No significant differences regarding all-cause mortality were found between patients in the first and second tertiles (HR: 0.96 [95% CI: 0.71 to 1.3; p = 0.78]). High levels of uric acid emerged as an independent predictor of all-cause mortality in patients with chronic total occlusion treated with PCI. Hence, uric acid levels should be incorporated into the risk assessment of patients with CTO.
    Type of Medium: Online Resource
    ISSN: 2077-0383
    URL: Article
    DOI: 10.3390/jcm12113794
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662592-1
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  • 5
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    Online Resource
    Incidence of COVID-19 Hospitalisation in Patients with Systemic Lupus Erythematosus: A Nationwide Cohort Study from Denmark
    MDPI AG ; 2021
    In:  Journal of Clinical Medicine Vol. 10, No. 17 ( 2021-08-27), p. 3842-
    Details
    In: Journal of Clinical Medicine, MDPI AG, Vol. 10, No. 17 ( 2021-08-27), p. 3842-
    Abstract: Background: Patients with systemic lupus erythematosus (SLE) have an increased risk of infections due to impaired immune functions, disease activity, and treatment. This study investigated the impact of having SLE on the incidence of hospitalisation with COVID-19 infection. Methods: This was a nationwide cohort study from Denmark between 1 March 2020 to 2 February 2021, based on the linkage of several nationwide registers. The adjusted incidence of COVID-19 hospitalisation was estimated for patients with SLE compared with the general population in Cox-regression models. Among SLE patients, the hazard ratio (HR) for hospitalisation was analysed as nested case-control study. Results: Sixteen of the 2533 SLE patients were hospitalised with COVID-19 infection. The age-sex adjusted rate per 1000 person years was 6.16 (95% CI 3.76–10.08) in SLE patients, and the corresponding hazard ratio was 2.54 (95% CI 1.55–4.16) compared with the matched general population group after adjustment for comorbidities. Among SLE patients, hydroxychloroquine treatment was associated with a HR for hospitalisation of 0.61 (95% CI 0.19–1.88), and 1.06 (95% CI 0.3–3.72) for glucocorticoid treatment. Conclusion: Patients with SLE were at increased risk of hospitalisation with COVID-19.
    Type of Medium: Online Resource
    ISSN: 2077-0383
    URL: Article
    DOI: 10.3390/jcm10173842
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662592-1
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  • 6
    Online Resource
    Online Resource
    Macrophage Migration Inhibitory Factor (MIF) Expression Increases during Myocardial Infarction and Supports Pro-Inflammatory Signaling in Cardiac Fibroblasts
    MDPI AG ; 2019
    In:  Biomolecules Vol. 9, No. 2 ( 2019-01-23), p. 38-
    Details
    In: Biomolecules, MDPI AG, Vol. 9, No. 2 ( 2019-01-23), p. 38-
    Abstract: Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine known to play a major role in inflammatory diseases such as myocardial infarction (MI), where its expression increases. Cardio protective functions of MIF during ischemia have been reported. Recently, the structurally related MIF-2 was identified and similar effects are assumed. We wanted to further investigate the role of MIF and MIF-2 on inflammatory processes during MI. Therefore, we subjected mice to experimentally induced MI by coronary occlusion for one and five days. During the acute phase of MI, the gene expression of Mif was upregulated in the infarct zone, whereas Mif-2 was downregulated, suggesting a minor role of MIF-2. Simulating ischemic conditions or mechanical stress in vitro, we demonstrated that Mif expression was induced in resident cardiac cells. To investigate possible auto /paracrine effects, cardiomyocytes and cardiac fibroblasts were individually treated with recombinant murine MIF, which in turn induced Mif expression and the expression of pro-inflammatory genes in cardiac fibroblasts. Cardiomyocytes did not respond to recombinant MIF with pro-inflammatory gene expression. While MIF stimulation alone did not change the expression of pro-fibrotic genes in cardiac fibroblasts, ischemia reduced their expression. Mimicking the increased MIF levels during MI, we exposed cardiac fibroblasts to simulated ischemia in the presence of MIF, which led to further reduced expression of pro-fibrotic genes. The presented data show that MIF was expressed by resident cardiac cells during MI. In vitro, Mif expression was induced by different external stimuli in cardiomyocytes and cardiac fibroblasts. Addition of recombinant MIF protein increased the expression of pro-inflammatory genes in cardiac fibroblasts including Mif expression itself. Thereby, cardiac fibroblasts may amplify Mif expression during ischemia promoting cardiomyocyte survival.
    Type of Medium: Online Resource
    ISSN: 2218-273X
    URL: Article
    DOI: 10.3390/biom9020038
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2701262-1
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  • 7
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    Online Resource
    Diagnostic Value of Soluble Urokinase-Type Plasminogen Activator Receptor in Addition to High-Sensitivity Troponin I in Early Diagnosis of Acute Myocardial Infarction
    MDPI AG ; 2019
    In:  Biomolecules Vol. 9, No. 3 ( 2019-03-18), p. 108-
    Details
    In: Biomolecules, MDPI AG, Vol. 9, No. 3 ( 2019-03-18), p. 108-
    Abstract: The soluble urokinase-type plasminogen activator receptor (suPAR) is a new marker for immune activation and inflammation and may provide diagnostic value on top of established biomarkers in patients with suspected acute myocardial infarction (AMI). Here, we evaluate the diagnostic potential of suPAR levels on top of high-sensitivity troponin I (hs-TnI) in a cohort of patients with suspected AMI. A total of 1220 patients presenting to the emergency department with suspected AMI were included, of whom 245 were diagnosed with AMI. Median suPAR levels at admission were elevated in subjects with AMI compared to non-AMI (3.8 ng/mL vs 3.3 ng/mL, p = 0.001). In C-statistics, the area under the curve (AUC) regarding the diagnosis of AMI was low (0.57 at an optimized cut-off of 3.7 ng/mL). Moreover, baseline suPAR levels on top of troponin values at admission and hour 1 reduced the number of patients who were correctly ruled-out as non-AMI, and who were correctly ruled-in as AMI. Our study shows that circulating levels of suPAR on top of high-sensitivity troponin I do not improve the early diagnosis of AMI.
    Type of Medium: Online Resource
    ISSN: 2218-273X
    URL: Article
    DOI: 10.3390/biom9030108
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2701262-1
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  • 8
    Online Resource
    Online Resource
    Transcriptional Active Parvovirus B19 Infection Predicts Adverse Long-Term Outcome in Patients with Non-Ischemic Cardiomyopathy
    MDPI AG ; 2021
    In:  Biomedicines Vol. 9, No. 12 ( 2021-12-14), p. 1898-
    Details
    In: Biomedicines, MDPI AG, Vol. 9, No. 12 ( 2021-12-14), p. 1898-
    Abstract: Parvovirus B19 (B19V) is the predominant cardiotropic virus currently found in endomyocardial biopsies (EMBs). However, direct evidence showing a causal relationship between B19V and progression of inflammatory cardiomyopathy are still missing. The aim of this study was to analyze the impact of transcriptionally active cardiotropic B19V infection determined by viral RNA expression upon long-term outcomes in a large cohort of adult patients with non-ischemic cardiomyopathy in a retrospective analysis from a prospective observational cohort. In total, the analyzed study group comprised 871 consecutive B19V-positive patients (mean age 50.0 ± 15.0 years) with non-ischemic cardiomyopathy who underwent EMB. B19V-positivity was ascertained by routine diagnosis of viral genomes in EMBs. Molecular analysis of EMB revealed positive B19V transcriptional activity in n = 165 patients (18.9%). Primary endpoint was all-cause mortality in the overall cohort. The patients were followed up to 60 months. On the Cox regression analysis, B19V transcriptional activity was predictive of a worse prognosis compared to those without actively replicating B19V (p = 0.01). Moreover, multivariable analysis revealed transcriptional active B19V combined with inflammation [hazard ratio 4.013, 95% confidence interval 1.515–10.629 (p = 0.005)] as the strongest predictor of impaired survival even after adjustment for age and baseline LVEF (p = 0.005) and independently of viral load. The study demonstrates for the first time the pathogenic clinical importance of B19V with transcriptional activity in a large cohort of patients. Transcriptionally active B19V infection is an unfavourable prognostic trigger of adverse outcome. Our findings are of high clinical relevance, indicating that advanced diagnostic differentiation of B19V positive patients is of high prognostic importance.
    Type of Medium: Online Resource
    ISSN: 2227-9059
    URL: Article
    DOI: 10.3390/biomedicines9121898
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2720867-9
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  • 9
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    Online Resource
    Design and Implementation of a Hierarchical Digital Twin for Power Systems Using Real-Time Simulation
    MDPI AG ; 2023
    In:  Electronics Vol. 12, No. 12 ( 2023-06-20), p. 2747-
    Details
    In: Electronics, MDPI AG, Vol. 12, No. 12 ( 2023-06-20), p. 2747-
    Abstract: This paper presents a hierarchical Digital Twin architecture and implementation that uses real-time simulation to emulate the physical grid and support grid planning and operation. With the demand for detailed grid information for automated grid operations and the ongoing transformation of energy systems, the Digital Twin can extend data acquisition by establishing a reliable real-time simulation. The system uses observer algorithms to process model information about the voltage dependencies of grid nodes, providing information about the dynamic behavior of the grid. The architecture implements multiple layers of data monitoring, processing, and simulation to create node-specific Digital Twins that are integrated into a real-time Hardware-in-the-Loop setup. The paper includes a simulation study that validates the accuracy of the Digital Twin, in terms of steady-state conditions, dynamic behavior, and required processing time. The results show that the proposed architecture can replicate the physical grid with high accuracy and corresponding dynamic behavior.
    Type of Medium: Online Resource
    ISSN: 2079-9292
    URL: Article
    DOI: 10.3390/electronics12122747
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662127-7
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  • 10
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    Online Resource
    Adverse Outcome Prediction of Iron Deficiency in Patients with Acute Coronary Syndrome
    MDPI AG ; 2018
    In:  Biomolecules Vol. 8, No. 3 ( 2018-07-20), p. 60-
    Details
    In: Biomolecules, MDPI AG, Vol. 8, No. 3 ( 2018-07-20), p. 60-
    Abstract: Acute myocardial infarction remains a leading cause of morbidity and mortality. While iron deficient heart failure patients are at increased risk of future cardiovascular events and see improvement with intravenous supplementation, the clinical relevance of iron deficiency in acute coronary syndrome remains unclear. We aimed to evaluate the prognostic value of iron deficiency in the acute coronary syndrome (ACS). Levels of ferritin, iron, and transferrin were measured at baseline in 836 patients with ACS. A total of 29.1% was categorized as iron deficient. The prevalence of iron deficiency was clearly higher in women (42.8%), and in patients with anemia (42.5%). During a median follow-up of 4.0 years, 111 subjects (13.3%) experienced non-fatal myocardial infarction (MI) and cardiovascular mortality as combined endpoint. Iron deficiency strongly predicted non-fatal MI and cardiovascular mortality with a hazard ratio (HR) of 1.52 (95% confidence interval (CI) 1.03-2.26; p = 0.037) adjusted for age, sex, hypertension, smoking status, diabetes, hyperlipidemia, body-mass-index (BMI) This association remained significant (HR 1.73 (95% CI 1.07–2.81; p = 0.026)) after an additional adjustment for surrogates of cardiac function and heart failure severity (N-terminal pro B-type natriuretic peptide, NT-proBNP), for the size of myocardial necrosis (troponin), and for anemia (hemoglobin). Survival analyses for cardiovascular mortality and MI provided further evidence for the prognostic relevance of iron deficiency (HR 1.50 (95% CI 1.02–2.20)). Our data showed that iron deficiency is strongly associated with adverse outcome in acute coronary syndrome.
    Type of Medium: Online Resource
    ISSN: 2218-273X
    URL: Article
    DOI: 10.3390/biom8030060
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2701262-1
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