growth dynamic
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Author(s):  
Ana P. Loureiro ◽  
Thaís Brasil ◽  
Lucas Correia ◽  
Walter Lilenbaum

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
I M Magaton ◽  
A Helmer ◽  
M Vo. Wolff ◽  
P Stute ◽  
M C Roumet

Abstract Study question Is endometrial growth and endometrial thickness different in controlled ovarian stimulation (COS)-IVF compared to unstimulated cycles and does this have an effect on pregnancy rates? Summary answer Endometrial growth dynamic is different and endometrium is thicker in COS-IVF but this does not have a positive effect on pregnancy and live birth rates. What is known already Endometrial growth and endometrial thickness are a function of duration and concentration of estradiol (E2) stimulation. Endometrial thickness <8mm is related with lower pregnancy rates in IVF treatments. It is commonly assumed that an increase of endometrial thickness by increasing estrogen stimulation could have a positive effect on pregnancy rate. However, such a relationship has never been systematically analysed. Natural Cycle IVF (NC-IVF) is an ideal model to analyse the effect of high dose gonadotropin stimulation on several parameters such as thickness of endometrium and pregnancy rate. Study design, size, duration Retrospective single center, University based study including 235 COS-IVF and 616 NC-IVF cycles from 2015 to 2019. Polyfollicular COS-IVF cycles were only analysed until 09 2017 as embryo selection was introduced in Switzerland afterwards. Limiting the analysis to cycles without embryo selection enabled us to compare embryos derived from cIVF and NC-IVF. 1550 endometrial and 1068 E2 measurements were included in the analysis. Participants/materials, setting, methods Mean female age at the time when the cycles were performed was in NC-IVF 35.8±3.9y and in COS-IVF 34.9±4.2y (maximum 42y). Each woman performed on average 1.96±1.45 IVF cycles. Endometrial thickness and E2 serum concentrations were evaluated daily between day –4 and –2 (0=day of aspiration). Pregnancy and live birth rate were evaluated per transferred embryo. Statistically, student test and a repeated measure model and a logistic regression model both adjusted for age were used. Main results and the role of chance Endometrial thickness was different in COS-IVF and NC-IVF. At each time point endometrial thickness was found to be higher in COS-IVF compared to NC-IVF (p < 0.001 on days –4,–3, and –2). On day –2, the day when ovulation was triggered, mean endometrial thickness was 9.75 ±2.05mm in COS-IVF and 8.12 ±1.66mm in NC-IVF. Endometrial growth dynamic was also different in COS-IVF and NC-IVF. Endometrial thickness increased significantly faster in NC-IVF cycles (0.58mm/day [0.43,0.73]) than in cIVF cycles (0.22mm/day [–0.12, 0.55], Pval= 0.034). The increase of endometrial thickness per day was less pronounced if E2 concentrations were high (–0.19 [–0.34, 0.05]). Therefore it can be assumed that the observed differences in growth dynamics in both treatments are caused by differences in E2. Increased endometrial thickness in COS-IVF was not associated with higher success rate. There was no significant effect of endometrium thickness on pregnancy (Pval=0.318) and Live birth rate (Pval=0.461). Limitations, reasons for caution Pregnancy and live birth rates might be affected by more than just endometrial thickness. The study was only based on the thickness of the endometrium but not on its ultrasound pattern. Wider implications of the findings: Postponing the aspiration to allow endometrium to further proliferate has only a limited effect in COS-IVF. Increasing gonadotropin stimulation dosage just to increase endometrial thickness is not a feasible strategy to improve pregnancy rate. The need to apply high dosages of estrogen supplementation in thawing cycles need to be questioned. Trial registration number “not applicable”


Lethaia ◽  
2021 ◽  
Author(s):  
María L. Fernández Dumont ◽  
Maria E. Pereyra ◽  
Paula Bona ◽  
Sebastián Apesteguía
Keyword(s):  

2021 ◽  
Vol 13 (1) ◽  
pp. 47
Author(s):  
V. L. Stass

The aim of this research was to translate a reading of a growth model of pigs to the modelling of growth of humans. The growth of individuals in the studied species is both a species-specific and phenotype-dependant process. The process is known as ontogenesis and has been considered as a dynamic system. The method used in the study was mathematical modelling. A hybrid model of animal's growth was applied to the experimental evidence to produce a reading of the growth dynamic. In the study, an earlier formulated analytical model of pig growth was developed to analyse a possible translation to the growth of humans. The study implies that in animals, the growth trajectory is phenotype-dependant, nonlinear and discontinuous. In some aspects such as saltatory growth and longevity as well as the discontinuous dynamic of the growth trajectory the translation of the results for the modelling the growth of humans were discussed.


2021 ◽  
Vol 8 ◽  
Author(s):  
Lori K. Fenton ◽  
Simone Silvestro ◽  
Gary Kocurek

In Scandia Cavi on Mars, barchans migrating over a field of transverse aeolian ridges (TARs) leave behind distinctive trails (“wakes”) comprising both TARs undergoing exhumation and coarse-grained ripples being shed from the barchans. With distance upwind from the barchans, the combined pattern of these bedforms coarsens and defect density decreases, thus appearing to mature with exposure time. We present results of morphological analyses of the wake bedform crestlines using HiRISE images, seeking to determine how the wake pattern reflects TAR growth and pattern development. TARs interact with each other, exhibiting defect repulsions and possible lobe extensions, indicating that these bedforms have migrated in the past, despite the lack of identifiable change in overlapping images spanning 9.5 years. Mapping one wake in detail, we found that the TAR pattern is not affected by superposing ripples. However, the ripples undergo many interactions, first with one another, and later (with distance upwind) with the underlying TARs. Near the dune, many ripples laterally link, growing in length, and they preferentially form along TAR crests, resulting in small bedform repulsions and longer superposing ripples. Most of these ripples will be consumed by the TARs, an as-yet unreported growth dynamic for TARs that is consistent with the work of others, who have found a continuum between TARs and the meter-scale ripples that form on dunes. Constructing a DTM, orthorectifying HiRISE images, and measuring dune migration rates places the timescale of ripple absorption by TARs in a wake at several thousand years, with the first ∼1,000 years dominated by lateral linking of ripples. Assuming that TAR growth is accomplished entirely through dune burial and subsequent ripple consumption, we estimate a lower limit age of the TARs, and by extension, the dune field, to be ∼270 kyr.


Author(s):  
Chenyang Bao ◽  
Xiang Peng ◽  
Yang Mei ◽  
Leiying Ying ◽  
Bao-Ping Zhang ◽  
...  

Since the emerging development of CsPbBr3 perovskite, chemical vapor deposition (CVD) became one of the most promising fabrication techniques to deposit precise, uniform perovskite thin films. However, the growth dynamic...


2020 ◽  
Vol 9 (8) ◽  
pp. 419-427
Author(s):  
Nidal Al‐Huniti ◽  
Yan Feng ◽  
Jingyu (Jerry) Yu ◽  
Zheng Lu ◽  
Mario Nagase ◽  
...  

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