Deterministic and robust room-temperature exchange coupling in monodomain multiferroic BiFeO3 heterostructures.

Exploiting multiferroic BiFeO3 thin films in spintronic devices requires deterministic and robust control of both internal magnetoelectric coupling in BiFeO3, as well as exchange coupling of its antiferromagnetic order to a ferromagnetic overlayer. Previous reports utilized approaches based on multi-step ferroelectric switching with multiple ferroelectric domains. Because domain walls can be responsible for fatigue, contain localized charges intrinsically or via defects, and present problems for device reproducibility and scaling, an alternative approach using a monodomain magnetoelectric state with single-step switching is desirable. Here we demonstrate room temperature, deterministic and robust, exchange coupling between monodomain BiFeO3 films and Co overlayer that is intrinsic (i.e., not dependent on domain walls). Direct coupling between BiFeO3 antiferromagnetic order and Co magnetization is observed, with ~ 90° in-plane Co moment rotation upon single-step switching that is reproducible for hundreds of cycles. This has important consequences for practical, low power non-volatile magnetoelectric devices utilizing BiFeO3.

Transgenerational effects of prenatal exposure to the 1944-45 Dutch famine.

OBJECTIVE: We previously showed that maternal under-nutrition during gestation is associated with increased metabolic and cardiovascular disease in the offspring. Also, we found increased neonatal adiposity among the grandchildren of women who had been undernourished during pregnancy. In the present study we investigated whether these transgenerational effects have led to altered body composition and poorer health in adulthood in the grandchildren. DESIGN: Historical cohort study. SETTING: Web-based questionnaire. POPULATION: The adult offspring (F2) of a cohort of men and women (F1) born around the time of the 1944-45 Dutch famine. METHODS: We approached the F2 adults through their parents. Participating F2 adults (n = 360, mean age 37 years) completed an online questionnaire. MAIN OUTCOME MEASURES: Weight, body mass index (BMI), and health in F2 adults, according to F1 prenatal famine exposure. RESULTS: Adult offspring (F2) of prenatally exposed F1 fathers had higher weights and BMIs than offspring of prenatally unexposed F1 fathers (+4.9 kg, P = 0.03; +1.6 kg/m(2), P = 0.006). No such effect was found for the F2 offspring of prenatally exposed F1 mothers. We observed no differences in adult health between the F2 generation groups. CONCLUSIONS: Offspring of prenatally undernourished fathers, but not mothers, were heavier and more obese than offspring of fathers and mothers who had not been undernourished prenatally. We found no evidence of transgenerational effects of grandmaternal under-nutrition during gestation on the health of this relatively young group, but the increased adiposity in the offspring of prenatally undernourished fathers may lead to increased chronic disease rates in the future.

Prenatal famine exposure, health in later life and promoter methylation of four candidate genes.

Poor nutrition during fetal development can permanently alter growth, cardiovascular physiology and metabolic function. Animal studies have shown that prenatal undernutrition followed by balanced postnatal nutrition alters deoxyribonucleic acid (DNA) methylation of gene promoter regions of candidate metabolic control genes in the liver. The aim of this study was to investigate whether methylation status of the proximal promoter regions of four candidate genes differed between individuals exposed to the Dutch famine in utero. In addition, we determined whether methylation status of these genes was associated with markers of metabolic and cardiovascular disease and adult lifestyle. Methylation status of the GR1-C (glucocorticoid receptor), PPARγ (peroxisome proliferator-activated receptor gamma), lipoprotein lipase and phosphatidylinositol 3 kinase p85 proximal promoters was investigated in DNA isolated from peripheral blood samples of 759 58-year-old subjects born around the time of the 1944-45 Dutch famine. We observed no differences in methylation levels of the promoters between exposed and unexposed men and women. Methylation status of PPARγ was associated with levels of high-density lipoprotein cholesterol and triglycerides as well as with exercise and smoking. Hypomethylation of the GR promoter was associated with adverse adult lifestyle factors, including higher body mass index, less exercise and more smoking. The previously reported increased risk of cardiovascular and metabolic disease after prenatal famine exposure was not associated with differences in methylation status across the promoter regions of these candidate genes measured in peripheral blood. The adult environment seems to affect GR and PPARγ promoter methylation.

The sex-specific effects of famine on the association between placental size and later hypertension.

BACKGROUND: People who had low birth weight are at increased risk of hypertension. This may reflect fetal programming by undernutrition. Placental size is also associated with hypertension. Maternal undernutrition during the Dutch famine reduced placental surface area. We examined whether maternal undernutrition altered the relationship between placental size and later hypertension. METHODS: Retrospective cohort study among 860 subjects born in Amsterdam during 1943-47. 216 subjects were taking anti-hypertensive medication. Birth records included placental length and breadth from which we calculated its area. RESULTS: Among men who were not in utero during the famine hypertension was associated with a small placental surface area due to a small placental breadth, and with an oval-shaped surface. The OR for hypertension was 0.83 (95% CI 0.70 to 1.00) for a 40 cm(2) increase in surface area. Among men who were in utero during the famine hypertension was associated with a large placental surface area due to a large placental breadth, and with a round-shaped surface. The OR for hypertension was 1.34 (95% CI 0.99 to 1.80) for a 40 cm(2) increase in surface area. The associations between placental size and hypertension in men who were and were not in utero during the famine were significantly different (p values for interaction = 0.008 for placental surface area, 0.001 for the breadth and 0.01 for the difference in the two diameters). Among women hypertension was not associated with placental size. CONCLUSIONS: Our study provides the first direct evidence that changes in maternal diet during pregnancy alter the relationship between placental size and later hypertension among men but not women. We suggest that among men who were not in utero during the famine, hypertension was related to impaired implantation, whereas among men who were in utero during the famine it was related to compensatory expansion of the placental surface.

Consequences of hyperemesis gravidarum for offspring: a systematic review and meta-analysis.

BACKGROUND: There is evidence that hyperemesis gravidarum (HG) is associated with a predominance of female fetuses, lower birthweights and shorter gestational ages at birth. As the adverse effects of prematurity and low birthweight on disease risk in later life have become increasingly clear, the repercussions of HG might not be limited to adverse perinatal outcomes. OBJECTIVES: To summarise the evidence on short- and long-term outcomes of pregnancies with HG. SEARCH STRATEGY: A literature search was conducted in the electronic databases Medline and Embase. SELECTION CRITERIA: Studies were included that reported on the fetal, neonatal and long-term outcome of pregnancies complicated by HG. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies and extracted data. Meta-analysis was performed using review manager. MAIN RESULTS: Women with HG during pregnancy were more likely to have a female child (OR 1.27; 95% CI 1.21-1.34). They were also more likely to have a baby with low birthweight (LBW, <2500 kg; OR 1.42; 95% CI 1.27-1.58) that was small for gestational age (SGA; OR 1.28; 95% CI 1.02-1.60), and to deliver prematurely (OR 1.32; 95% CI 1.04-1.68). There was no association with Apgar scores, congenital anomalies or perinatal death. One study described an association between HG and testicular cancer in the offspring. AUTHOR'S CONCLUSIONS: There is evidence that HG is associated with a higher female/male ratio of offspring and a higher incidence of LBW, SGA and premature babies. Little is known about the long-term health effects of babies born to mothers whose pregnancies were complicated by HG.

Effects of famine on placental size and efficiency.

BACKGROUND: Placental growth responds to maternal influences including diet. We have examined placental size, shape and efficiency among babies born around the time of the 5-month wartime famine in Holland 1944-1945. METHODS: We examined the birth records of 2414 term singleton babies born in Amsterdam during 1943-1947. The records included the size of the baby and the thickness of the placental surface, together with its length and breadth which we used to calculate its area and volume. RESULTS: Compared to babies born before the famine babies who were in utero during the famine had smaller placental areas. Babies whose mothers conceived after the famine ended also had smaller placental areas. Famine was associated with a 19 cm(2) decrease in area. Babies who were in mid-late gestation during the famine were 160 g lighter than would have been predicted from their placental area (p < 0.001). Babies who were in early gestation during the famine, or who were conceived after it had ended were 102 g heavier than would have been predicted from their placental area (p < 0.001). These latter babies were either longer or had larger head circumferences depending on when the mother experienced the famine. Among babies who were in early gestation during the famine the reduction in placental area was greater in boys than girls (p for interaction 0.03). CONCLUSION: Famine impaired the normal processes of placentation, even among babies who were conceived after it had ended. In babies who were in mid-late gestation during the famine, the placenta was less efficient. In babies who were in early gestation during the famine, or who were conceived after it had ended, the placenta was more efficient. The placentas of boys and girls responded differently to famine.