scholarly journals On the Role of Dilute Solute Additions on Growth Restriction in Binary Copper Alloys

2020 ◽  
Vol 9 (6) ◽  
pp. 825-832
Author(s):  
M. J. Balart ◽  
F. Gao ◽  
J. B. Patel ◽  
F. Miani
Keyword(s):  
Copper Alloys ◽  
Growth Restriction ◽  
Restriction Factor ◽  
Modeling Framework ◽  
Solute Content ◽  
Grain Length ◽  
Cu Alloys ◽  
Acta Mater ◽  
Columnar Grain

AbstractThe effect of dilute solute additions on growth restriction in binary Cu alloys has been assessed at different degrees of superheat. Columnar grain length values from Northcott’s work (Northcott in J Inst Metals 62:101-136, 1938) for binary Cu alloys were plotted against the corresponding undercooling parameter (P), the reciprocal of the conventional (Qconv.) and true (Qtrue) growth restriction factor (Schmid-Fetzer and Kozlov in Acta Mater 59(15):6133-6144, 2011) values. It was found that there was no correlation between the columnar grain length values and P, 1/Qconv. and 1/Qtrue values for different solutes and cast at the same degree of superheat. Unlike P, Qconv., and Qtrue values, the heuristic growth restriction parameter (β) (Fan et al. in Acta Mater 152, 248-257, 2018) modeling framework in conjunction with the critical solute content (C*) for growth restriction fitted well to binary Cu alloys.

scholarly journals Ultrasonic Vibration as a Primary Mixing Tool in Accelerating Aluminum–Copper Alloys Preparation from Their Pure Elements

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 781
Author(s):  
Abdulsalam Muhrat ◽  
Hélder Puga ◽  
Joaquim Barbosa
Keyword(s):  
Ultrasonic Vibration ◽  
Copper Alloys ◽  
Grain Refining ◽  
Alloying Element ◽  
Experimental Conditions ◽  
Melt Temperature ◽  
Cu Alloys ◽  
Aluminum Copper Alloys ◽  
Main Factor

In this study, ultrasonic vibration (USV) was evaluated in preparation of Al–8wt.%Cu alloys at a lab-scale. Moreover, the role of Ti–6Al–4V sonotrode erosion and its contribution in grain refining were analyzed. Based on the experimental conditions/parameters, it was found that the amount of impurities and the associated porosity were significantly reduced in USV treated alloys. Furthermore, USV reduced the time needed for dissolving the alloying element Cu, nevertheless, the best dissolving of Cu in this study was not possible without introducing further holding time. As a result of using a titanium-based sonotrode, a noticeable content of Ti was found in the ultrasonically treated alloys due to sonotrode erosion under USV. The dispersion of TiAl3 promoted, as a main factor, a grain refining effect at relatively constant and high melt temperature, other possible mechanisms of grain refining have been discussed.

scholarly journals Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

The Role of the Anti-Angiogenic Factor Endostatin in Intrauterine Growth Restriction

2005 ◽  
Vol 12 (3) ◽  
pp. 195-197 ◽  
Author(s):  
Ariadne Malamitsi-Puchner ◽  
Theodora Boutsikou ◽  
Emmanuel Economou ◽  
Evangelos Makrakis ◽  
Zoe Iliodromiti ◽  
...  
Keyword(s):  
Intrauterine Growth Restriction ◽  
Growth Restriction ◽  
Angiogenic Factor ◽  
Intrauterine Growth

scholarly journals The Role of HLAC and NK Cells in Fetal Growth Restriction

2017 ◽  
pp. 142
Author(s):  
Sri Sulistyawati ◽  
Didon M Trimulya ◽  
Supriyadi H Respati ◽  
Soetrisno Soetrisno
Keyword(s):  
Nk Cells ◽  
Fetal Growth ◽  
Fetal Growth Restriction ◽  
Nk Cell ◽  
Normal Pregnancy ◽  
Growth Restriction ◽  
Immunohistochemical Method ◽  
Cross Sectional ◽  
The Mean

Objective: To determine the role of HLA-C and NK cell expressions in fetal growth restriction (FGR). Methods: A cross sectional study design was used. This study was conducted at the Obstetrics and Gynecology Department of Dr. Moewardi General Hospital, Surakarta, its affiliated hospitals, and at the Pathological Anatomy Laboratory of the Faculty of Medicine, University of Sebelas Maret Surakarta. A total of 40 samples were included in this study. The samples consisted of 20 normal pregnancies and 20 pregnancies with FGR. HLA-C expression in the trophoblast and NK cells in decidua of the subjects who met the inclusion and exclusion criteria were examined using immunohistochemical method and statistical analysis with T test. Results: The mean expression of HLA-C in the trophoblast in the pregnant group with FGR was 9.021.30, normal pregnancy was 7.96 ± 0.97, p=0.01 (p<0.05). The mean expression of NK cells in decidua of pregnancy with FGR was 10.59 ± 2.11, normal pregnancy was 0.91 ± 8.18, with p=0.00 (p<0.05). Conclusion: The expressions of HLA-C in trophoblast and NK cells in decidua of pregnancy with FGR were higher compared with those of normal pregnancy. [Indones J Obstet Gynecol 2017; 5-3: 142-148] Keywords: fetal growth restriction, HLA-C, NK cells

The brain development of infants with intrauterine growth restriction: role of glucocorticoids

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Ying-xue Ding ◽  
Hong Cui
Keyword(s):  
Endothelial Cells ◽  
Brain Injury ◽  
Intrauterine Growth Restriction ◽  
Growth And Development ◽  
Growth Restriction ◽  
Microvascular Endothelial Cells ◽  
Intrauterine Growth ◽  
Growth Restrictions ◽  
The Brain

Abstract Brain injury is a serious complication of intrauterine growth restriction (IUGR), but the exact mechanism remains unclear. While glucocorticoids (GCs) play an important role in intrauterine growth and development, GCs also have a damaging effect on microvascular endothelial cells. Moreover, intrauterine adverse environments lead to fetal growth restriction and the hypothalamus-pituitary-adrenal (HPA) axis resetting. In addition, chronic stress can cause a decrease in the number and volume of astrocytes in the hippocampus and glial cells play an important role in neuronal differentiation. Therefore, it is speculated that the effect of GCs on cerebral neurovascular units under chronic intrauterine stimulation is an important mechanism leading to brain injury in infants with growth restrictions.

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