20,689 research outputs found
Tobacco use in the third trimester of pregnancy and its relationship to birth weight. A prospective study in Spain
Background Few studies have been carried out in Spain examining the use of tobacco amongst expectant mothers and its effect on birth weight. Aims To observe the proportion of expectant mothers who smoke during their pregnancy, and the impact of tobacco consumption on maternal and birth weight. We also aimed to identify the trimester of pregnancy in which tobacco use produced the greatest reduction in birth weight. Methods Prospective observational study in Spain. A random sampling strategy was used to select health centres and participant women. A total of 137 individuals were enrolled in the study. Exposure to tobacco was measured through a self-reported questionnaire. Regressions were performed to obtain a predictive model for birth weight related to smoking. Findings Overall, 35% of study participants were smokers during the pre-gestational period (27% in the first trimester, 21.9% in the second and 21.2% in the third). 38.7% of smoking cessation attempts took place in the third-trimester. Pregnant women who smoked up to the third trimester had a higher risk of giving birth to a baby under 3000 g, compared to non-smokers (OR = 5.94, CI 95%: 1.94–18.16). Each additional unit of tobacco consumed daily in the 3rd trimester led to a 32 g reduction in birth weight. Conclusion An important proportion of pregnant women in Spain smoke during pregnancy. Pregnant women exposed to tobacco have newborns with lower birth weight. Smoking during the 3rd trimester of pregnancy is associated with the greatest risk of lower birth weight
Interplay between the magnetic anisotropy contributions of Cobalt nanowires
We report on the magnetic properties and the crystallographic structure of
the cobalt nanowire arrays as a function of their nanoscale dimensions. X-ray
diffraction measurements show the appearance of an in-plane HCP-Co phase for
nanowires with 50 nm diameter, suggesting a partial reorientation of the
magnetocrystalline anisotropy axis along the membrane plane with increasing
pore diameter. No significant changes in the magnetic behavior of the nanowire
system are observed with decreasing temperature, indicating that the effective
magnetoelastic anisotropy does not play a dominant role in the remagnetization
processes of individual nanowires. An enhancement of the total magnetic
anisotropy is found at room temperature with a decreasing nanowire
diameter-to-length ratio (d/L), a result that is quantitatively analyzed on the
basis of a simplified shape anisotropy model.Comment: 8 pages, 4 figure
Disordered CYP11B2 Expression in Primary Aldosteronism
Primary aldosteronism is the most common type of secondary hypertension affecting 6-10% of patients with primary hypertension. PA is mainly caused by unilateral hyperaldosteronism due to an aldosterone-producing adenoma, unilateral hyperplasia with or without micronodules or bilateral zona glomerulosa hyperplasias with or without macro or micronodules. The development of antibodies against the terminal enzyme of aldosterone biosynthesis (CYP11B2) has permitted the further characterization of normal adrenals and resected adrenals from patients with primary aldosteronism. Normal adrenals exhibit two different patterns of cellular expression of CYP11B2: young individuals display a relatively uniform expression of the enzyme throughout the zona glomerulosa while the adrenals of older individuals have dispersed CYP11B2-expressing cells but have more groups of cells called aldosterone-producing cell clusters (APCC). APAs exhibit different patterns of CYP11B2 staining that vary from uniform to homogeneous. There are also a proportion of cells within the APA that co-express different enzymes that are not normally co-expressed in normal individuals. Approximately 30% of patients with unilateral hyperaldosteronism do not have an APA, but either have an increased number of CYP11B2 expressing micronodules or hyperplasia of the zona glomerulosa. In summary, the studies reported in this review are shedding new light on the pathophysiology of primary aldosteronism. The wide variation in histopathological features of the adenomas and concurrent presence of APCCs raises the possibility that most cases of unilateral production of aldosterone actually might represent bilateral asymmetric hyperplasia with nodules frequently due to the development of somatic aldosterone-driving mutations
Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association
We present the discovery of a companion near the deuterium burning mass limit
located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec
(projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very
young Upper Scorpius association. Optical and near-infrared photometry and
spectroscopy confirm the cool nature of both objects, with spectral types of M7
and M9.5, respectively, and that they are bona fide members of the association,
showing low gravity and features of youth. Their masses, estimated from the
comparison of their bolometric luminosities and theoretical models for the age
range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The
existence of this object around a brown dwarf at this wide orbit suggests that
the companion is unlikely to have formed in a disk based on current planet
formation models. Because this system is rather weakly bound, they did not
probably form through dynamical ejection of stellar embryos.Comment: 10 pages, including 4 figures and 2 table
Design of Allosteric Stimulators of the Hsp90 ATPase as New Anticancer Leads
Allosteric compounds that stimulate Hsp90 adenosine triphosphatase (ATPase) activity were rationally designed, showing anticancer potencies in the low micromolar to nanomolar range. In parallel, the mode of action of these compounds was clarified and a quantitative model that links the dynamic ligand-protein cross-talk to observed cellular and in vitro activities was developed. The results support the potential of using dynamics-based approaches to develop original mechanism-based cancer therapeutics
The origin of the Acheulean: the 1.7 million-year-old site of FLK West, Olduvai Gorge (Tanzania)
The appearance of the Acheulean is one of the hallmarks of human evolution. It represents the
emergence of a complex behavior, expressed in the recurrent manufacture of large-sized tools, with
standardized forms, implying more advance forethought and planning by hominins than those required
by the precedent Oldowan technology. The earliest known evidence of this technology dates back to
c. 1.7 Ma. and is limited to two sites (Kokiselei [Kenya] and Konso [Ethiopia]), both of which lack fauna.
The functionality of these earliest Acheulean assemblages remains unknown. Here we present the
discovery of another early Acheulean site also dating to c. 1.7 Ma from Olduvai Gorge. This site provides
evidence of the earliest steps in developing the Acheulean technology and is the oldest Acheulean site in
which stone tools occur spatially and functionally associated with the exploitation of fauna. Simple and
elaborate large-cutting tools (LCT) and handaxes co-exist at FLK West, showing that complex cognition
was present from the earliest stages of the Acheulean. Here we provide a detailed technological study
and evidence of the use of these tools on the butchery and consumption of fauna, probably by early
Homo erectus sensu lato
An improved model of the Earth's gravitational field: GEM-T1
Goddard Earth Model T1 (GEM-T1), which was developed from an analysis of direct satellite tracking observations, is the first in a new series of such models. GEM-T1 is complete to degree and order 36. It was developed using consistent reference parameters and extensive earth and ocean tidal models. It was simultaneously solved for gravitational and tidal terms, earth orientation parameters, and the orbital parameters of 580 individual satellite arcs. The solution used only satellite tracking data acquired on 17 different satellites and is predominantly based upon the precise laser data taken by third generation systems. In all, 800,000 observations were used. A major improvement in field accuracy was obtained. For marine geodetic applications, long wavelength geoidal modeling is twice as good as in earlier satellite-only GEM models. Orbit determination accuracy has also been substantially advanced over a wide range of satellites that have been tested
Mouse models of primary aldosteronism: from physiology to pathophysiology
Primary aldosteronism (PA) is a common form of endocrine hypertension that is characterized by the excessive production of aldosterone relative to suppressed plasma renin levels. PA is usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations have been identified in several genes that encode ion pumps and channels that may explain the aldosterone excess in over half of aldosterone-producing adenomas, whereas the pathophysiology of bilateral adrenal hyperplasia is largely unknown. A number of mouse models of hyperaldosteronism have been described that recreate some features of the human disorder although none replicate the genetic basis of human PA. Animal models that reproduce the genotype-phenotype associations of human PA are required to establish the functional mechanisms that underlie the endocrine autonomy and deregulated cell growth of the affected adrenal and for preclinical studies of novel therapeutics. Herein, we discuss the differences in adrenal physiology across species and describe the genetically-modified mouse models of PA that have been developed to date
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