40 research outputs found
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests.
OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs).
METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability.
RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli.
CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests.
OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs).
METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability.
RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli.
CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests. OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs). METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability. RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli. CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Electronic Properties of Vinylene-Linked Heterocyclic Conducting Polymers: Predictive Design and Rational Guidance from DFT Calculations
The band structure and electronic properties in a series of vinylene-linked
heterocyclic conducting polymers are investigated using density functional
theory (DFT). In order to accurately calculate electronic band gaps, we utilize
hybrid functionals with fully periodic boundary conditions to understand the
effect of chemical functionalization on the electronic structure of these
materials. The use of predictive first-principles calculations coupled with
simple chemical arguments highlights the critical role that aromaticity plays
in obtaining a low band gap polymer. Contrary to some approaches which
erroneously attempt to lower the band gap by increasing the aromaticity of the
polymer backbone, we show that being aromatic (or quinoidal) in itself does not
insure a low band gap. Rather, an iterative approach which destabilizes the
ground state of the parent polymer towards the aromatic \leftrightarrow
quinoidal level-crossing on the potential energy surface is a more effective
way of lowering the band gap in these conjugated systems. Our results highlight
the use of predictive calculations guided by rational chemical intuition for
designing low band gap polymers in photovoltaic materials.Comment: Accepted by the Journal of Physical Chemistry
Optoelectronic and Excitonic Properties of Oligoacenes: Substantial Improvements from Range-Separated Time-Dependent Density Functional Theory
The optoelectronic and excitonic properties in a series of linear acenes
(naphthalene up to heptacene) are investigated using range-separated methods
within time-dependent density functional theory (TDDFT). In these rather simple
systems, it is well-known that TDDFT methods using conventional hybrid
functionals surprisingly fail in describing the low-lying La and Lb valence
states, resulting in large, growing errors for the La state and an incorrect
energetic ordering as a function of molecular size. In this work, we
demonstrate that the range-separated formalism largely eliminates both of these
errors and also provides a consistent description of excitonic properties in
these systems. We further demonstrate that re-optimizing the percentage of
Hartree-Fock exchange in conventional hybrids to match wavefunction-based
benchmark calculations still yields serious errors, and a full 100%
Hartree-Fock range separation is essential for simultaneously describing both
of the La and Lb transitions. Based on an analysis of electron-hole transition
density matrices, we finally show that conventional hybrid functionals
overdelocalize excitons and underestimate quasiparticle energy gaps in the
acene systems. The results of our present study emphasize the importance of
both a range-separated and asymptotically-correct contribution of exchange in
TDDFT for investigating optoelectronic and excitonic properties, even for these
simple valence excitations.Comment: Accepted by the Journal of Chemical Theory and Computatio
The Northern Belt 100 years on : a revised model of the Ordovician tracts near Leadhills, Scotland
A new model for the provenance, depositional environment and tectonic setting of the Northern Belt of the Southern Uplands is presented. This turbiditic sandstone dominated sequence was deposited in a sand-rich submarine fan environment, overlying hemipelagic mudstones. The oldest sandstones are rich in juvenile ophiolitic material and record the first clastic input into the Southern Uplands basin. The bulk of the Northern Belt sedimentary sequence, however, is dominated by relatively quartzose sandstones derived from a Proterozoic continental/metamorphic source represented by the Midland Valley terrane of Scotland and Ireland. The quartzose dominated sequence was punctuated by the input of fresh volcanic detritus shed from a oceanic/continental island-arc situated to the W/NW of the Southern Uplands basin, with sediment dispersal turning to the NE along the axis of the basin in Scotland. The tectonic setting of the Southern Upland basin remains uncertain. The complex provenance of the sandstones and recognition of major olistostrome units within the Northern Belt succession suggest that it was tectonically active. The onset of clastic deposition within the Southern Uplands broadly corresponds to ophiolite obduction in both Scotland and Ireland, possibly in response to collision of a Cambrian-early Ordovician island-arc system with the Laurentian continental margin. If this interpretation is correct then the possibility arises that the Southern Uplands-Midland Valley terranes record the dismembering of this island-arc complex within an overall transpressional regime
Experimental and Chemoinformatics Study of Tautomerism in a Database of Commercially Available Screening Samples
We
investigated how many cases of the same chemical sold as different
products (at possibly different prices) occurred in a prototypical
large aggregated database and simultaneously tested the tautomerism
definitions in the chemoinformatics toolkit CACTVS. We applied the
standard CACTVS tautomeric transforms plus a set of recently developed
ringâchain transforms to the Aldrich Market Select (AMS) database
of 6 million screening samples and building blocks. In 30âŻ000
cases, two or more AMS products were found to be just different tautomeric
forms of the same compound. We purchased and analyzed 166 such tautomer
pairs and triplets by <sup>1</sup>H and <sup>13</sup>C NMR to determine
whether the CACTVS transforms accurately predicted what is the same
âstuff in the bottleâ. Essentially all prototropic transforms
with examples in the AMS were confirmed. Some of the ringâchain
transforms were found to be too âaggressiveâ, i.e. to
equate structures with one another that were different compounds
Exploring the influence of indololactone structure on selectivity for binding to the C1 domains of PKCα, PKCΔ, and RasGRP
C1 domain-containing proteins, such as protein kinase C (PKC), have a central role in cellular signal transduction. Their involvement in many diseases, including cancer, cardiovascular disease, and immunological and neurological disorders has been extensively demonstrated and has prompted a search for small molecules to modulate their activity. By employing a diacylglycerol (DAG)-lactone template, we have been able to develop ultra potent analogs of diacylglycerol with nanomolar binding affinities approaching those of complex natural products such as phorbol esters and bryostatins. One current challenge is the development of selective ligands capable of discriminating between different protein family members. Recently, structure-activity relationship studies have shown that the introduction of an indole ring as a DAG-lactone substituent yielded selective Ras guanine nucleotide-releasing protein (RasGRP1) activators when compared to PKCα and PKCΔ. In the present work, we examine the effects of ligand selectivity relative to the orientation of the indole ring and the nature of the DAG-lactone template itself. Our results show that the indole ring must be attached to the lactone moiety through the sn-2 position in order to achieve RasGRP1 selectivity.Fil: Elhalem, Eleonora. Instituto Nacional de TecnologĂa Industrial; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Gandolfi DonadĂo, LucĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Instituto Nacional de TecnologĂa Industrial; ArgentinaFil: Zhou, Xiaoling. National Cancer Institute; Estados UnidosFil: Lewin, Nancy E.. National Cancer Institute; Estados UnidosFil: Garcia, Lia Cynthia. Instituto Nacional de TecnologĂa Industrial; ArgentinaFil: Lai, Christopher C.. National Institutes of Health; Estados UnidosFil: Kelley, James A.. National Institutes of Health; Estados UnidosFil: Peach, Megan L.. National Institutes of Health; Estados UnidosFil: Blumberg, Peter M.. National Cancer Institute; Estados UnidosFil: Comin, Maria Julieta. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Instituto Nacional de TecnologĂa Industrial; Argentin