Effects of Strontium,Magnesium Addition,Temperature Gradient,and Growth Velocity on Al-Si Eutectic Growth in a Unidirectionally-solidified Al-13 wt%,Si Alloy

Al-Si eutectic growth mechanism was investigated in a directionally-solidified AI-1 3 wt% Si alloy with different strontium （Sr） and magnesium （Mg） additions, growth velocities and temperature gradients. Macro- and micro- scale metallographic analyses revealed that addition level of Sr and Mg, temperature gradient and growth velocity are important factors affecting stability of solidifying AI-Si eutectic front and the final morphology of eutectic grains in the solidified A1-13 wt% Si alloys. By varying （tailoring） these factors, a variety of eutectic grain structures and morphologies such as planar front, cellular structure, a mix of cellular and columnar, or equiaxed dendrites, can be obtained. Increasing temperature gradient, reducing growth velocity, or decreasing Sr and Mg contents is beneficial to stabilizing planar growth front of eutectic grains, which is qualitatively in accordance with constitutional supercooling criterion for binary eutectic growth. In contrast, adding more Sr and Mg, increasing growth velocity, or decreasing temperature gradient produces large constitutional supercooling, leading to columnar-equiaxed transition （CET） of eutectic structure, which can be interpreted on the basis of Hunt＇s Model. It is also found that both solute concentration and solidification variables have significant impact not only on eutectic growth, but also on gas porosity formation.

Growth-Promoting Effect of Recombinant Human Growth Hormone and Stanozolol in Girls with Turner Syndrome

Summary: Ten girls with Turner syndrome were treated with a combination therapy of recombinant human growth hormone (R hGH) and low dose stanozolol for a period of 8 to 36 months. The results showed that when compared with the growth rate before the treatment, the growth rates after treatment with R hGH and stanozolol showed a sustained increase, reaching 9.0±1.9 cm/year during the first year of treatment; the height age increase by 2.5±0.8 years while the bone age increase were 1.0±0.7 years; and the predicted final adult height at the end of the first year of the treatment increased to 149.4±6.1 cm compared to their original mean of 142.8±4.2 cm. We are led to conclude that therapy with R hGH in combination with stanozolol can increase the growth velocity and significantly increase the predicted adult height of children with Turner syndrome.

Comparative Analyses of Height Growth Velocities of School Boys in South Korea and Japan in the Past 50 Years

The paper compares the height growth velocities of male schoolchildren in South Korea and Japan over the period 1961-2018. Growth in height was measured with the same birth cohorts, not by comparing mean height of ascending ages in the same year. Starting from a lower economic base and mean height in the 1960s, high school males aged 17 in South Korea became 3 cm taller in mean height than their Japanese peers in the mid-2000s versus 2 - 3 cm shorter in the 1960s through 1970s. Children in Japan ceased to grow taller by the end of the 1980s, not because they quit taking more animal-sourced foods, meat and milk, but because they had drastically steered away from fruit and vegetables in their diets since the end of the 1970s. Having largely converged economically with Japan, South Korean children ceased to grow any taller in the mid-2000s. More importantly, it was discovered in this study that successive cohorts in South Korea started to fall gradually but steadily in height growth velocity from 1st graders in middle school, aged 12 years to 3rd graders in high school, and aged 17 years, to be once again 3 cm below their Japanese peers in the early-2010s. Analysis of Korea Household Expenditure Surveys classified by age groups of household head, decomposed by the author, revealed that children under 20 years of age in South Korea began to steer away from fruit and, particularly, vegetables in their at-home consumption in the mid-1990s, to average only 15% of the level of older adults in their 50s in the mid-2010s. These results lend supports to the importance of fruit and vegetables as determinants in height and its growth velocities in two genetically similar nations over time and stages of economic growth.

The Dutch, The World Tallest Are Shrinking in the Latest Decade or So: The Lessons from the Case of South Korea and Japan in North-East Asia

The Dutch have been the world tallest since the 1980s but plateaued in height for the past few decades. A century and a half ago, young men at 20 in the Netherlands were 165 cm in mean height, as tall as men in France and Portugal. They grew to 178 cm, as tall as Norwegian in 1960, and 183 cm in mean height in the 1990s and levelled off. It is most likely that the Dutch may have nearly attained genetic potential as a human being. The statue is a net measure that captures the supply of inputs to health. Based on the changes in per capita supply of protein from animal products, FAOSTAT, the Dutch seem to have reached the highest level in per capita supply of animal protein. Increases in the supply of protein, however, do not result in increasing human height, if consumption of other “essential nutrients” is insufficient (Blum, 2013;Mori, 2018)[1][2]. With the close case studies of Japan and South Korea in respect of food consumption specifically by children in growing ages, the author suspects that children in the Netherlands may have been insufficient in the supply of vegetables, “essential nutrients” on the top of animal products.

Review on second-harmonic generation of ultrasonic guided waves in solid media(Ⅰ): Theoretical analyses

Considering the high sensitivity of the nonlinear ultrasonic measurement technique and great advantages of the guided wave testing method, the use of nonlinear ultrasonic guided waves provides a promising means for evaluating and characterizing the hidden and/or inaccessible damage/degradation in solid media. Increasing attention on the development of the testing method based on nonlinear ultrasonic guided waves is largely attributed to the theoretical advances of nonlinear guided waves propagation in solid media. One of the typical acoustic nonlinear responses is the generation of second harmonics that can be used to effectively evaluate damage/degradation in materials/structures. In this paper, the theoretical progress of second-harmonic generation（SHG） of ultrasonic guided wave propagation in solid media is reviewed. The advances and developments of theoretical investigations on the effect of SHG of ultrasonic guided wave propagation in different structures are addressed. Some obscure understandings and the ideas in dispute are also discussed.

Effect of long-term Helicobacter pylori infection on growth of children:a cohort study

Background:The effects of Helicobacter pylori(H.pylori)infection on growth are a controversial issue.We investigated the effects of long-term H.pylori infection on height and weight in children.Methods:A total of 200 children of 7-18 years old suffering from dyspeptic complaints were classified into two groups:H.pylori positive and negative groups,respectively.Whether the infection was impoved was followed up while performing urea breath test,and according to exposure time to the infection,the children were further divided into group 1(≤1.5 months),group 2(>1.5-≤6 months)and group 3(>6 months).Antropometric measurements were obtained and repeated every six months.Results:Mean growth velocity scores in the H.pylori positive and negative groups were 0.49±3.85[95%confidence interval(CI):-0.21-1.18]and 1.98±4.42(95%CI:1-2.96),respectively.The difference between both groups was statistically significant(P=0.012).Mean growth velocity scores in groups 1,2 and 3 were 0.96±3.84,0.16±4.51 and-0.85±3.09,respectively.Mean growth velocity scores of group 3 were significantly lower than those of groups 0 and 1(P=0.005 and P=0.041).The mean weight scores in group 3 were similar to those in group 2,but the scores in group 3 were signifi cantly lower than those in group 1(-1.75±1.05,-1.21±1.37 and-0.88±1.49,respectively).Conclusion:As the duration of exposure is prolonged in children with H.pylori infection,the negative effect of the infection on both height and weight is evident.