Südame areng ja kaasasündinud rikked. Biomehaaniline perspektiiv

Südamerikked ilmnevad umbes 1%-l elusalt sündinud lastest. Uuringud on näidanud, et kõigist kaasasündinud riketest esinevad kõige sagedamini südamerikked. Viimase aja uuringud on esile toonud mitmeid põhjusi, mis soodustavad kaasasündinud südamerikete kujunemist. Ühelt poolt võib sellel olla molekulaarbioloogiline põhjus – geenimutatsioon –, mis on tingitud nukleotiidide muutustest geenides (1). Teiselt poolt on mõjuteguriks emakasisene keskkond, mida võib mõjutada ema eluviis ja käitumine, näiteks alkoholitarbimine, suitsetamine, narkootikumide, ravimite tarvitamine (2, 3). Samuti võib embrüo areng olla häiritud mõningate toitainete puudusest emal, näiteks foolhappe puudus ja sellest tulenev homotsüsteiinisisalduse suurenemine veres (4). Kirjeldatud tegurid võivad mõjutada loote arengut väga varajases perioodis, kui ema veel ei teagi, et ta on rase. Harilikult tuvastab naine raseduse 5.–6. nädalal pärast viljastumist. Tuksuv süda ja vereringe kujuneb lootel juba 3. viljastumisjärgsel nädalal (16.–21. päeval). Seega võivad südame arengut mõjutavad tegurid toimida juba siis, kui naine ei olegi oma rasedusest teadlik. Südamerikete kujunemise põhjuste selgitamiseks on vaja uurida loote arengu väga varajasi perioode. Eesti Arst 2013; 92(2):80–8

Life prediction and constitutive models for engine hot section anisotropic materials program

This report presents the results of the first year of a program designed to develop life prediction and constitutive models for two coated single crystal alloys used in gas turbine airfoils. The two alloys are PWA 1480 and Alloy 185. The two oxidation resistant coatings are PWA 273, an aluminide coating, and PWA 286, an overlay NiCoCrAlY coating. To obtain constitutive and/or fatigue data, tests were conducted on coated and uncoated PWA 1480 specimens tensilely loaded in the 100 , 110 , 111 , and 123 directions. A literature survey of constitutive models was completed for both single crystal alloys and metallic coating materials; candidate models were selected. One constitutive model under consideration for single crystal alloys applies Walker's micromechanical viscoplastic formulation to all slip systems participating in the single crystal deformation. The constitutive models for the overlay coating correlate the viscoplastic data well. For the aluminide coating, a unique test method is under development. LCF and TMF tests are underway. The two coatings caused a significant drop in fatigue life, and each produced a much different failure mechanism

The Heart-Placenta Axis in the First Month of Pregnancy: Induction and Prevention of Cardiovascular Birth Defects

Extrapolating from animal studies to human pregnancy, our studies showed that folate (FA) deficiency as well as one-time exposure to environmental factors in the first two to three weeks of human gestation can result in severe congenital heart defects (CHDs). Considering that approximately 49% of pregnancies are unplanned, this period of pregnancy can be considered high-risk for cardiac, as well as for neural, birth defects, as the woman usually is not aware of her pregnancy and may not yet be taking precautionary actions to protect the developing embryo. Using avian and mouse vertebrate models, we demonstrated that FA supplementation prevents CHD induced by alcohol, lithium, or elevation of the metabolite homocysteine, a marker for FA deficiency. All three factors affected the important Wnt signaling pathway by suppressing Wnt-mediated gene expression in the heart fields, resulting in a delay of cardiomyocyte migration, cardiomyogenesis, and CHD. Optimal protection of cardiogenesis was observed to occur with FA supplementation provided upon morning after conception and at higher doses than the presently available in prenatal vitamin supplementation. Our studies demonstrate pathways and cell processes that are involved with protection of one-carbon metabolism during heart development

Learning Effects of the Flipped Classroom in a Principles of Microeconomics Course Running Header: Flipped Principles of Micro

The authors of this article estimate the learning effects of the flipped classroom format using data from 16 sections of principles of microeconomics over a 4-year period. The experimental design is unique in that two treatment and two control sections were taught during the fall semester in four consecutive years. Further, the instructor switched the time of day when the treatment and control sections were taught each year. Controlling for gender, ACT score, a normed high school GPA, Pell Grant award, time of day, and initial knowledge of economics, the authors find no evidence of increased learning using end-of-semester measures for students in the flipped classroom in comparison to sections with a moderate amount of active learning

Measuring Faculty Teaching Effectiveness Using Conditional Fixed Effects

Using a dataset of 48 faculty members and 88 courses over 26 semesters, the authors estimate Student Evaluation of Teaching (SET) ratings that are conditional on a multitude of course, faculty, and student attributes. They find that ratings are lower for required courses and those where students report a lower prior level of interest. Controlling for these variables substantially alters the SET ratings for many instructors. The average absolute value of the difference between the faculty ratings controlling just for time effects and fully conditional ratings is nearly one-half of a standard deviation in the students’ rating of how much they learned. This difference produces a change in quartile rank for over half the sample across two summary course evaluation measures

Could tariffs be pro-cyclical?

Conventional wisdom says that tariffs are counter-cyclical. We analyze the relationship between business cycles and applied MFN tariffs using a disaggregated product-level panel dataset covering 72 countries between 2000 and 2011. Strikingly, and counter to conventional wisdom, we find that tariffs are pro-cyclical. Further investigation reveals that this pro-cyclicality is driven by the tariff setting behavior of developing countries; tariffs are acyclical in developed countries. We present evidence that pro-cyclical market power drives the pro-cyclicality of tariffs in developing countries, providing further evidence of the importance of terms of trade motivations in explaining trade policy

Costly distribution and the non-equivalence of tariffs and quotas

When governments impose a quota or tariff on imports, it is well known that the resulting rents and revenues trigger costly rent-seeking and revenue-seeking activities, which are welfare-reducing and may be economically more significant than the efficiency losses resulting from the protectionist-induced resource misallocation. Repeated interaction among firms can eliminate wasteful rent- and revenue-seeking expenditures through cooperation. We show that while aggregate outcomes are equivalent under tariffs and quotas if cooperation arises, the conditions under which cooperation arises differ by policy. This difference arises because a firm must incur additional cost to physically import and distribute the goods associated with additional quota licenses, whereas there is no such cost when it comes to consuming additional tariff revenue. Thus, quotas and tariffs are non-equivalent. We provide a simple sufficient condition under which cooperative elimination of rent-seeking under quotas is easier than cooperative elimination of revenue-seeking under tariffs and therefore a quota is the preferred policy whenever the policy admits cooperation

Domestic political competition and pro-cyclical import protection

Governments, especially in developing countries, routinely practice binding overhang (i.e. setting applied tariffs below binding WTO commitments) and frequently move applied tariffs for given products up and down over the business cycle. Moreover, applied tariffs are pro-cyclical in developing countries. We explain this phenomenon using a dynamic theory of lobbying between domestic interest groups. Applied tariffs are pro-cyclical when high-tariff interests (e.g. import-competing industries) capture the government: these groups concede lower tariffs to low-tariff interest groups (e.g. exporting firms or firms using imported intermediate inputs) during recessions because recessions lower the opportunity cost of lobbying and thereby generate a stronger lobbying threat

Suggestions for Early Career Community-Engaged Scholars

This document was written specifically, though not exclusively, for early career faculty members doing (or would like to be doing) faculty work in collaboration with off-campus community partners. The document may also be helpful to faculty members at other career stages who are beginning to undertake community-engaged work and administrators seeking to support their faculty. This is the information we wish we had at the start of our careers. We, the five co-authors of this paper, are tenured community-engaged faculty members and seasoned higher education administrators specializing in civic and community-engaged academic practices. Based on our literature review and collective lived experiences, we have focused this paper on three topics we believe are critical for early career community-engaged faculty members to understand more deeply. These three topics include developing your identity statement, finding your mentors, and documenting your scholarship

Baicalin administration attenuates hyperglycemia-induced malformation of cardiovascular system

In this study, the effects of Baicalin on the hyperglycemia-induced cardiovascular malformation during embryo development were investigated. Using early chick embryos, an optimal concentration of Baicalin (6 μM), was identified which could prevent hyperglycemia-induced cardiovascular malformation of embryos. Hyperglycemia-enhanced cell apoptosis was reduced in embryos and HUVECs in the presence of Baicalin. Hyperglycemia-induced excessive ROS production was inhibited when Baicalin was administered. Analyses of SOD, GSH-Px, MAQE and GABAA suggested Baicalin plays an antioxidant role in chick embryos possibly through suppression of outwardly rectifying Cl(-) in the high-glucose microenvironment. In addition, hyperglycemia-enhanced autophagy fell in the presence of Baicalin, through affecting the ubiquitin of p62 and accelerating autophagy flux. Both Baicalin and Vitamin C could decrease apoptosis, but CQ did not, suggesting autophagy to be a protective function on the cell survival. In mice, Baicalin reduced the elevated blood glucose level caused by streptozotocin (STZ). Taken together, these data suggest that hyperglycemia-induced embryonic cardiovascular malformation can be attenuated by Baicalin administration through suppressing the excessive production of ROS and autophagy. Baicalin could be a potential candidate drug for women suffering from gestational diabetes mellitus