MDPI - Publisher of Open Access Journals

17 pages, 4350 KB

Open AccessArticle

Influence of Deep Cryogenic Treatment on the Mechanical Properties and Corrosion Resistance of Nickel–Aluminum Bronze

by Carmen M. Abreu, Iria Feijoo, Gloria Pena and M. Consuelo Pérez

Corros. Mater. Degrad. 2024, 5(4), 624-640; https://doi.org/10.3390/cmd5040030 - 19 Dec 2024

Viewed by 1246

The objective of this research is to enhance the mechanical and corrosion resistance properties of a cast Ni-Al bronze (NAB). To achieve this, the effect of deep cryogenic treatment (DCT), a process that has shown promise in other alloys, is initially investigated. It is demonstrated that, in the case of NAB, DCT induces only minor microstructural changes, which do not lead to any significant improvement in its properties. Consequently, it is proposed that a combined treatment be employed, involving annealing either before or after DCT. The results indicate that annealing at 675 °C for 2 h following cryogenic treatment at −180 °C increases the yield strength by approximately 11%. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in simulated seawater further confirm that this combination results in the formation of oxide layers with enhanced protective capacity. These improvements are attributed to the significant refinement and homogenization of the microstructure, including the globularization of the kI, kII, and, particularly, kIII phases, and an increase in the precipitation of the kIV phase in a finer and more homogeneous form within the alpha phase. Full article

(This article belongs to the Special Issue Effects of Cryogenic Treatment on the Corrosion and Materials Degradation)

► Show Figures

Figure 1

15 pages, 1748 KB

Open AccessArticle

Comprehensive Analysis of the Genetic Variation in the LPA Gene from Short-Read Sequencing

by Raphael O. Betschart, Georgios Koliopanos, Paras Garg, Linlin Guo, Massimiliano Rossi, Sebastian Schönherr, Stefan Blankenberg, Raphael Twerenbold, Tanja Zeller and Andreas Ziegler

BioMed 2024, 4(2), 156-170; https://doi.org/10.3390/biomed4020013 - 4 Jun 2024

Viewed by 2477

Abstract

Lipoprotein (a) (Lp(a)) is a risk factor for cardiovascular diseases and mainly regulated by the complex LPA gene. We investigated the types of variation in the LPA gene and their predictive performance on Lp(a) concentration. We determined the Kringle IV-type 2 (KIV-2) copy number (CN) using the DRAGEN LPA Caller (DLC) and a read depth-based CN estimator in 8351 short-read whole genome sequencing samples from the GENESIS-HD study. The pentanucleotide repeat in the promoter region was genotyped with GangSTR and ExpansionHunter. Lp(a) concentration was available in 4861 population-based subjects. Predictive performance on Lp(a) concentration was investigated using random forests. The agreement of the KIV-2 CN between the two specialized callers was high (r = 0.9966; 95% confidence interval [CI] 0.9965–0.9968). Allele-specific KIV-2 CN could be determined in 47.0% of the subjects using the DLC. Lp(a) concentration can be better predicted from allele-specific KIV-2 CN than total KIV-2 CN. Two single nucleotide variants, 4925G>A and rs41272114C>T, further improved prediction. The genetically complex LPA gene can be analyzed with excellent agreement between different callers. The allele-specific KIV-2 CN is more important for predicting Lp(a) concentration than the total KIV-2 CN. Full article

► Show Figures

Figure 1

14 pages, 2380 KB

Open AccessArticle

Haplotype of the Lipoprotein(a) Gene Variants rs10455872 and rs3798220 Is Associated with Parameters of Coagulation, Fibrinolysis, and Inflammation in Patients after Myocardial Infarction and Highly Elevated Lipoprotein(a) Values

by Sabina Ugovšek, Andreja Rehberger Likozar, Tina Levstek, Katarina Trebušak Podkrajšek, Janja Zupan and Miran Šebeštjen

Int. J. Mol. Sci. 2024, 25(2), 736; https://doi.org/10.3390/ijms25020736 - 6 Jan 2024

Cited by 2 | Viewed by 3447

Abstract

Lipoprotein(a) (Lp(a)) is an independent risk factor for future coronary events. Variants rs10455872 and rs3798220 in the gene encoding Lp(a) are associated with an increased Lp(a) concentration and risk of coronary artery disease. We aimed to determine whether in high-risk coronary artery disease patients these two genetic variants and the kringle IV type 2 (KIV-2) repeats are associated with impairment of inflammatory and hemostatic parameters. Patients after myocardial infarction with elevated Lp(a) levels were included. Blood samples underwent biochemical and genetic analyses. In carriers of the AC haplotype, the concentrations of tumor necrosis factor (TNF)-α (4.46 vs. 3.91 ng/L, p = 0.046) and plasminogen activator inhibitor-1 (PAI-1) (p = 0.026) were significantly higher compared to non-carriers. The number of KIV-2 repeats was significantly associated with the concentration of high-sensitivity C-reactive protein (ρ = 0.251, p = 0.038) and overall fibrinolytic potential (r = −0.253, p = 0.038). In our patients, a direct association between the AC haplotype and both TNF-α and PAI-1 levels was observed. Our study shows that the number of KIV-2 repeats not only affects proatherosclerotic and proinflammatory effects of Lp(a) but is also associated with its antifibrinolytic properties. Full article

(This article belongs to the Special Issue Molecular Mechanisms and Pathophysiology of Atherosclerosis 2.0)

► Show Figures

Figure 1

14 pages, 882 KB

Open AccessReview

Assessment of Apolipoprotein(a) Isoform Size Using Phenotypic and Genotypic Methods

by Federica Fogacci, Valentina Di Micoli, Ashot Avagimyan, Marina Giovannini, Egidio Imbalzano and Arrigo F. G. Cicero

Int. J. Mol. Sci. 2023, 24(18), 13886; https://doi.org/10.3390/ijms241813886 - 9 Sep 2023

Cited by 14 | Viewed by 2694

Abstract

Apolipoprotein(a) (apo(a)) is the protein component that defines lipoprotein(a) (Lp(a)) particles and is encoded by the LPA gene. The apo(a) is extremely heterogeneous in size due to the copy number variations in the kringle-IV type 2 (KIV2) domains. In this review, we aim to discuss the role of genetics in establishing Lp(a) as a risk factor for coronary heart disease (CHD) by examining a series of molecular biology techniques aimed at identifying the best strategy for a possible application in clinical research and practice, according to the current gold standard. Full article

(This article belongs to the Special Issue Lipoprotein Metabolism in Health and Disease)

► Show Figures

Figure 1

13 pages, 1582 KB

Open AccessArticle

Effectiveness of Prenyl Group on Flavonoids from Epimedium koreanum Nakai on Bacterial Neuraminidase Inhibition

by Hong Min Choi, Jeong Yoon Kim, Zuo Peng Li, Janar Jenis, Yeong Jun Ban, Aizhamal Baiseitova and Ki Hun Park

Molecules 2019, 24(2), 317; https://doi.org/10.3390/molecules24020317 - 16 Jan 2019

Cited by 35 | Viewed by 4527

Abstract

In this study, the inhibitory potential of bacterial neuraminidase (NA) was observed on the leaves of Epimedium koreanum Nakai, which is a popular ingredient in traditional herbal medicine. This study attempted to isolate the relevant, responsible metabolites and elucidate their inhibition mechanism. The methanol extraction process yielded eight flavonoids (1–8), of which compounds 7 and 8 were new compounds named koreanoside F and koreanoside G, respectively. All the compounds (1–8) showed a significant inhibition to bacterial NA with IC₅₀ values of 0.17–106.3 µM. In particular, the prenyl group on the flavonoids played a critical role in bacterial NA inhibition. Epimedokoreanin B (compound 1, IC₅₀ = 0.17 µM) with two prenyl groups on C8 and C5′ of luteolin was 500 times more effective than luteolin (IC₅₀ = 85.6 µM). A similar trend was observed on compound 2 (IC₅₀ = 0.68 µM) versus dihydrokaempferol (IC₅₀ = 500.4 µM) and compound 3 (IC₅₀ = 12.6 µM) versus apigenin (IC₅₀ = 107.5 µM). Kinetic parameters (K_m, V_max, and K_ik/K_iv) evaluated that all the compounds apart from compound 5 showed noncompetitive inhibition. Compound 5 was proven to be a mixed type inhibitor. In an enzyme binding affinity experiment using fluorescence, affinity constants (K_SV) were tightly related to inhibitory activities. Full article

(This article belongs to the Special Issue Trends in the Development of Enzyme Inhibitors)

► Show Figures

Figure 1

Search Results (5)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (5)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI